Update ZFS from version 6 to 13 and bring some FreeBSD-specific changes.

This bring huge amount of changes, I'll enumerate only user-visible changes:

- Delegated Administration

	Allows regular users to perform ZFS operations, like file system
	creation, snapshot creation, etc.

- L2ARC

	Level 2 cache for ZFS - allows to use additional disks for cache.
	Huge performance improvements mostly for random read of mostly
	static content.

- slog

	Allow to use additional disks for ZFS Intent Log to speed up
	operations like fsync(2).

- vfs.zfs.super_owner

	Allows regular users to perform privileged operations on files stored
	on ZFS file systems owned by him. Very careful with this one.

- chflags(2)

	Not all the flags are supported. This still needs work.

- ZFSBoot

	Support to boot off of ZFS pool. Not finished, AFAIK.

	Submitted by:	dfr

- Snapshot properties

- New failure modes

	Before if write requested failed, system paniced. Now one
	can select from one of three failure modes:
	- panic - panic on write error
	- wait - wait for disk to reappear
	- continue - serve read requests if possible, block write requests

- Refquota, refreservation properties

	Just quota and reservation properties, but don't count space consumed
	by children file systems, clones and snapshots.

- Sparse volumes

	ZVOLs that don't reserve space in the pool.

- External attributes

	Compatible with extattr(2).

- NFSv4-ACLs

	Not sure about the status, might not be complete yet.

	Submitted by:	trasz

- Creation-time properties

- Regression tests for zpool(8) command.

Obtained from:	OpenSolaris

161 files changed, 70855 insertions, 10363 deletions

diff --git a/sys/cddl/contrib/opensolaris/common/acl/acl_common.c b/sys/cddl/contrib/opensolaris/common/acl/acl_common.c
index 2f32e7a8a78a..e6b678079635 100644
--- a/sys/cddl/contrib/opensolaris/common/acl/acl_common.c
+++ b/sys/cddl/contrib/opensolaris/common/acl/acl_common.c
@@ -2,9 +2,8 @@
  * CDDL HEADER START
  *
  * The contents of this file are subject to the terms of the
- * Common Development and Distribution License, Version 1.0 only
- * (the "License").  You may not use this file except in compliance
- * with the License.
+ * Common Development and Distribution License (the "License").
+ * You may not use this file except in compliance with the License.
  *
  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
  * or http://www.opensolaris.org/os/licensing.
@@ -20,100 +19,245 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
 #pragma ident	"%Z%%M%	%I%	%E% SMI"
 
 #include <sys/types.h>
-#include <sys/acl.h>
 #include <sys/stat.h>
+#include <sys/avl.h>
+#include <sys/misc.h>
 #if defined(_KERNEL)
+#include <sys/kmem.h>
 #include <sys/systm.h>
+#include <sys/sysmacros.h>
+#include <acl/acl_common.h>
 #include <sys/debug.h>
 #else
 #include <errno.h>
 #include <stdlib.h>
+#include <stddef.h>
 #include <strings.h>
+#include <unistd.h>
 #include <assert.h>
+#include <grp.h>
+#include <pwd.h>
+#include <acl_common.h>
 #define	ASSERT	assert
 #endif
 
+#define	ACE_POSIX_SUPPORTED_BITS (ACE_READ_DATA | \
+    ACE_WRITE_DATA | ACE_APPEND_DATA | ACE_EXECUTE | \
+    ACE_READ_ATTRIBUTES | ACE_READ_ACL | ACE_WRITE_ACL)
+
+
+#define	ACL_SYNCHRONIZE_SET_DENY		0x0000001
+#define	ACL_SYNCHRONIZE_SET_ALLOW		0x0000002
+#define	ACL_SYNCHRONIZE_ERR_DENY		0x0000004
+#define	ACL_SYNCHRONIZE_ERR_ALLOW		0x0000008
+
+#define	ACL_WRITE_OWNER_SET_DENY		0x0000010
+#define	ACL_WRITE_OWNER_SET_ALLOW		0x0000020
+#define	ACL_WRITE_OWNER_ERR_DENY		0x0000040
+#define	ACL_WRITE_OWNER_ERR_ALLOW		0x0000080
+
+#define	ACL_DELETE_SET_DENY			0x0000100
+#define	ACL_DELETE_SET_ALLOW			0x0000200
+#define	ACL_DELETE_ERR_DENY			0x0000400
+#define	ACL_DELETE_ERR_ALLOW			0x0000800
+
+#define	ACL_WRITE_ATTRS_OWNER_SET_DENY		0x0001000
+#define	ACL_WRITE_ATTRS_OWNER_SET_ALLOW		0x0002000
+#define	ACL_WRITE_ATTRS_OWNER_ERR_DENY		0x0004000
+#define	ACL_WRITE_ATTRS_OWNER_ERR_ALLOW		0x0008000
+
+#define	ACL_WRITE_ATTRS_WRITER_SET_DENY		0x0010000
+#define	ACL_WRITE_ATTRS_WRITER_SET_ALLOW	0x0020000
+#define	ACL_WRITE_ATTRS_WRITER_ERR_DENY		0x0040000
+#define	ACL_WRITE_ATTRS_WRITER_ERR_ALLOW	0x0080000
+
+#define	ACL_WRITE_NAMED_WRITER_SET_DENY		0x0100000
+#define	ACL_WRITE_NAMED_WRITER_SET_ALLOW	0x0200000
+#define	ACL_WRITE_NAMED_WRITER_ERR_DENY		0x0400000
+#define	ACL_WRITE_NAMED_WRITER_ERR_ALLOW	0x0800000
+
+#define	ACL_READ_NAMED_READER_SET_DENY		0x1000000
+#define	ACL_READ_NAMED_READER_SET_ALLOW		0x2000000
+#define	ACL_READ_NAMED_READER_ERR_DENY		0x4000000
+#define	ACL_READ_NAMED_READER_ERR_ALLOW		0x8000000
+
+
+#define	ACE_VALID_MASK_BITS (\
+    ACE_READ_DATA | \
+    ACE_LIST_DIRECTORY | \
+    ACE_WRITE_DATA | \
+    ACE_ADD_FILE | \
+    ACE_APPEND_DATA | \
+    ACE_ADD_SUBDIRECTORY | \
+    ACE_READ_NAMED_ATTRS | \
+    ACE_WRITE_NAMED_ATTRS | \
+    ACE_EXECUTE | \
+    ACE_DELETE_CHILD | \
+    ACE_READ_ATTRIBUTES | \
+    ACE_WRITE_ATTRIBUTES | \
+    ACE_DELETE | \
+    ACE_READ_ACL | \
+    ACE_WRITE_ACL | \
+    ACE_WRITE_OWNER | \
+    ACE_SYNCHRONIZE)
+
+#define	ACE_MASK_UNDEFINED			0x80000000
+
+#define	ACE_VALID_FLAG_BITS (ACE_FILE_INHERIT_ACE | \
+    ACE_DIRECTORY_INHERIT_ACE | \
+    ACE_NO_PROPAGATE_INHERIT_ACE | ACE_INHERIT_ONLY_ACE | \
+    ACE_SUCCESSFUL_ACCESS_ACE_FLAG | ACE_FAILED_ACCESS_ACE_FLAG | \
+    ACE_IDENTIFIER_GROUP | ACE_OWNER | ACE_GROUP | ACE_EVERYONE)
+
+/*
+ * ACL conversion helpers
+ */
+
+typedef enum {
+	ace_unused,
+	ace_user_obj,
+	ace_user,
+	ace_group, /* includes GROUP and GROUP_OBJ */
+	ace_other_obj
+} ace_to_aent_state_t;
+
+typedef struct acevals {
+	uid_t key;
+	avl_node_t avl;
+	uint32_t mask;
+	uint32_t allowed;
+	uint32_t denied;
+	int aent_type;
+} acevals_t;
+
+typedef struct ace_list {
+	acevals_t user_obj;
+	avl_tree_t user;
+	int numusers;
+	acevals_t group_obj;
+	avl_tree_t group;
+	int numgroups;
+	acevals_t other_obj;
+	uint32_t acl_mask;
+	int hasmask;
+	int dfacl_flag;
+	ace_to_aent_state_t state;
+	int seen; /* bitmask of all aclent_t a_type values seen */
+} ace_list_t;
 
 ace_t trivial_acl[] = {
-	{-1, 0, ACE_OWNER, ACE_ACCESS_DENIED_ACE_TYPE},
-	{-1, ACE_WRITE_ACL|ACE_WRITE_OWNER|ACE_WRITE_ATTRIBUTES|
+	{(uid_t)-1, 0, ACE_OWNER, ACE_ACCESS_DENIED_ACE_TYPE},
+	{(uid_t)-1, ACE_WRITE_ACL|ACE_WRITE_OWNER|ACE_WRITE_ATTRIBUTES|
 	    ACE_WRITE_NAMED_ATTRS, ACE_OWNER, ACE_ACCESS_ALLOWED_ACE_TYPE},
-	{-1, 0, ACE_GROUP|ACE_IDENTIFIER_GROUP, ACE_ACCESS_DENIED_ACE_TYPE},
-	{-1, 0, ACE_GROUP|ACE_IDENTIFIER_GROUP, ACE_ACCESS_ALLOWED_ACE_TYPE},
-	{-1, ACE_WRITE_ACL|ACE_WRITE_OWNER| ACE_WRITE_ATTRIBUTES|
+	{(uid_t)-1, 0, ACE_GROUP|ACE_IDENTIFIER_GROUP,
+	    ACE_ACCESS_DENIED_ACE_TYPE},
+	{(uid_t)-1, 0, ACE_GROUP|ACE_IDENTIFIER_GROUP,
+	    ACE_ACCESS_ALLOWED_ACE_TYPE},
+	{(uid_t)-1, ACE_WRITE_ACL|ACE_WRITE_OWNER| ACE_WRITE_ATTRIBUTES|
 	    ACE_WRITE_NAMED_ATTRS, ACE_EVERYONE, ACE_ACCESS_DENIED_ACE_TYPE},
-	{-1, ACE_READ_ACL|ACE_READ_ATTRIBUTES|ACE_READ_NAMED_ATTRS|
+	{(uid_t)-1, ACE_READ_ACL|ACE_READ_ATTRIBUTES|ACE_READ_NAMED_ATTRS|
 	    ACE_SYNCHRONIZE, ACE_EVERYONE, ACE_ACCESS_ALLOWED_ACE_TYPE}
 };
 
 
 void
-adjust_ace_pair(ace_t *pair, mode_t mode)
+adjust_ace_pair_common(void *pair, size_t access_off,
+    size_t pairsize, mode_t mode)
 {
+	char *datap = (char *)pair;
+	uint32_t *amask0 = (uint32_t *)(uintptr_t)(datap + access_off);
+	uint32_t *amask1 = (uint32_t *)(uintptr_t)(datap + pairsize +
+	    access_off);
 	if (mode & S_IROTH)
-		pair[1].a_access_mask |= ACE_READ_DATA;
+		*amask1 |= ACE_READ_DATA;
 	else
-		pair[0].a_access_mask |= ACE_READ_DATA;
+		*amask0 |= ACE_READ_DATA;
 	if (mode & S_IWOTH)
-		pair[1].a_access_mask |=
-		    ACE_WRITE_DATA|ACE_APPEND_DATA;
+		*amask1 |= ACE_WRITE_DATA|ACE_APPEND_DATA;
 	else
-		pair[0].a_access_mask |=
-		    ACE_WRITE_DATA|ACE_APPEND_DATA;
+		*amask0 |= ACE_WRITE_DATA|ACE_APPEND_DATA;
 	if (mode & S_IXOTH)
-		pair[1].a_access_mask |= ACE_EXECUTE;
+		*amask1 |= ACE_EXECUTE;
 	else
-		pair[0].a_access_mask |= ACE_EXECUTE;
+		*amask0 |= ACE_EXECUTE;
+}
+
+void
+adjust_ace_pair(ace_t *pair, mode_t mode)
+{
+	adjust_ace_pair_common(pair, offsetof(ace_t, a_access_mask),
+	    sizeof (ace_t), mode);
+}
+
+static void
+ace_allow_deny_helper(uint16_t type, boolean_t *allow, boolean_t *deny)
+{
+	if (type == ACE_ACCESS_ALLOWED_ACE_TYPE)
+		*allow = B_TRUE;
+	else if (type == ACE_ACCESS_DENIED_ACE_TYPE)
+		*deny = B_TRUE;
 }
 
 /*
  * ace_trivial:
  * determine whether an ace_t acl is trivial
  *
- * Trivialness implys that the acl is composed of only
+ * Trivialness implies that the acl is composed of only
  * owner, group, everyone entries.  ACL can't
  * have read_acl denied, and write_owner/write_acl/write_attributes
  * can only be owner@ entry.
  */
 int
-ace_trivial(ace_t *acep, int aclcnt)
+ace_trivial_common(void *acep, int aclcnt,
+    uint64_t (*walk)(void *, uint64_t, int aclcnt,
+    uint16_t *, uint16_t *, uint32_t *))
 {
-	int i;
-	int owner_seen = 0;
-	int group_seen = 0;
-	int everyone_seen = 0;
+	boolean_t owner_allow = B_FALSE;
+	boolean_t group_allow = B_FALSE;
+	boolean_t everyone_allow = B_FALSE;
+	boolean_t owner_deny = B_FALSE;
+	boolean_t group_deny = B_FALSE;
+	boolean_t everyone_deny = B_FALSE;
+	uint16_t flags;
+	uint32_t mask;
+	uint16_t type;
+	uint64_t cookie = 0;
 
-	for (i = 0; i != aclcnt; i++) {
-		switch (acep[i].a_flags & 0xf040) {
+	while (cookie = walk(acep, cookie, aclcnt, &flags, &type, &mask)) {
+		switch (flags & ACE_TYPE_FLAGS) {
 		case ACE_OWNER:
-			if (group_seen || everyone_seen)
+			if (group_allow || group_deny || everyone_allow ||
+			    everyone_deny)
 				return (1);
-			owner_seen++;
+			ace_allow_deny_helper(type, &owner_allow, &owner_deny);
 			break;
 		case ACE_GROUP|ACE_IDENTIFIER_GROUP:
-			if (everyone_seen || owner_seen == 0)
+			if (everyone_allow || everyone_deny &&
+			    (!owner_allow && !owner_deny))
 				return (1);
-			group_seen++;
+			ace_allow_deny_helper(type, &group_allow, &group_deny);
 			break;
 
 		case ACE_EVERYONE:
-			if (owner_seen == 0 || group_seen == 0)
+			if (!owner_allow && !owner_deny &&
+			    !group_allow && !group_deny)
 				return (1);
-			everyone_seen++;
+			ace_allow_deny_helper(type,
+			    &everyone_allow, &everyone_deny);
 			break;
 		default:
 			return (1);
 
 		}
 
-		if (acep[i].a_flags & (ACE_FILE_INHERIT_ACE|
+		if (flags & (ACE_FILE_INHERIT_ACE|
 		    ACE_DIRECTORY_INHERIT_ACE|ACE_NO_PROPAGATE_INHERIT_ACE|
 		    ACE_INHERIT_ONLY_ACE))
 			return (1);
@@ -124,27 +268,49 @@ ace_trivial(ace_t *acep, int aclcnt)
 		 * Don't allow anybody to deny reading basic
 		 * attributes or a files ACL.
 		 */
-		if ((acep[i].a_access_mask &
-		    (ACE_READ_ACL|ACE_READ_ATTRIBUTES)) &&
-		    (acep[i].a_type == ACE_ACCESS_DENIED_ACE_TYPE))
+		if ((mask & (ACE_READ_ACL|ACE_READ_ATTRIBUTES)) &&
+		    (type == ACE_ACCESS_DENIED_ACE_TYPE))
 			return (1);
 
 		/*
 		 * Allow on owner@ to allow
 		 * write_acl/write_owner/write_attributes
 		 */
-		if (acep[i].a_type == ACE_ACCESS_ALLOWED_ACE_TYPE &&
-		    (!(acep[i].a_flags & ACE_OWNER) && (acep[i].a_access_mask &
+		if (type == ACE_ACCESS_ALLOWED_ACE_TYPE &&
+		    (!(flags & ACE_OWNER) && (mask &
 		    (ACE_WRITE_OWNER|ACE_WRITE_ACL|ACE_WRITE_ATTRIBUTES))))
 			return (1);
+
 	}
 
-	if ((owner_seen == 0) || (group_seen == 0) || (everyone_seen == 0))
-	    return (1);
+	if (!owner_allow || !owner_deny || !group_allow || !group_deny ||
+	    !everyone_allow || !everyone_deny)
+		return (1);
 
 	return (0);
 }
 
+uint64_t
+ace_walk(void *datap, uint64_t cookie, int aclcnt, uint16_t *flags,
+    uint16_t *type, uint32_t *mask)
+{
+	ace_t *acep = datap;
+
+	if (cookie >= aclcnt)
+		return (0);
+
+	*flags = acep[cookie].a_flags;
+	*type = acep[cookie].a_type;
+	*mask = acep[cookie++].a_access_mask;
+
+	return (cookie);
+}
+
+int
+ace_trivial(ace_t *acep, int aclcnt)
+{
+	return (ace_trivial_common(acep, aclcnt, ace_walk));
+}
 
 /*
  * Generic shellsort, from K&R (1st ed, p 58.), somewhat modified.
@@ -171,8 +337,8 @@ ksort(caddr_t v, int n, int s, int (*f)())
 	for (g = n / 2; g > 0; g /= 2) {
 		for (i = g; i < n; i++) {
 			for (j = i - g; j >= 0 &&
-				(*f)(v + j * s, v + (j + g) * s) == 1;
-					j -= g) {
+			    (*f)(v + j * s, v + (j + g) * s) == 1;
+			    j -= g) {
 				p1 = (void *)(v + j * s);
 				p2 = (void *)(v + (j + g) * s);
 				for (ii = 0; ii < s / 4; ii++) {
@@ -215,3 +381,1347 @@ cmp2acls(void *a, void *b)
 	/* Totally equal */
 	return (0);
 }
+
+/*ARGSUSED*/
+static void *
+cacl_realloc(void *ptr, size_t size, size_t new_size)
+{
+#if defined(_KERNEL)
+	void *tmp;
+
+	tmp = kmem_alloc(new_size, KM_SLEEP);
+	(void) memcpy(tmp, ptr, (size < new_size) ? size : new_size);
+	kmem_free(ptr, size);
+	return (tmp);
+#else
+	return (realloc(ptr, new_size));
+#endif
+}
+
+static int
+cacl_malloc(void **ptr, size_t size)
+{
+#if defined(_KERNEL)
+	*ptr = kmem_zalloc(size, KM_SLEEP);
+	return (0);
+#else
+	*ptr = calloc(1, size);
+	if (*ptr == NULL)
+		return (errno);
+
+	return (0);
+#endif
+}
+
+/*ARGSUSED*/
+static void
+cacl_free(void *ptr, size_t size)
+{
+#if defined(_KERNEL)
+	kmem_free(ptr, size);
+#else
+	free(ptr);
+#endif
+}
+
+acl_t *
+acl_alloc(enum acl_type type)
+{
+	acl_t *aclp;
+
+	if (cacl_malloc((void **)&aclp, sizeof (acl_t)) != 0)
+		return (NULL);
+
+	aclp->acl_aclp = NULL;
+	aclp->acl_cnt = 0;
+
+	switch (type) {
+	case ACE_T:
+		aclp->acl_type = ACE_T;
+		aclp->acl_entry_size = sizeof (ace_t);
+		break;
+	case ACLENT_T:
+		aclp->acl_type = ACLENT_T;
+		aclp->acl_entry_size = sizeof (aclent_t);
+		break;
+	default:
+		acl_free(aclp);
+		aclp = NULL;
+	}
+	return (aclp);
+}
+
+/*
+ * Free acl_t structure
+ */
+void
+acl_free(acl_t *aclp)
+{
+	int acl_size;
+
+	if (aclp == NULL)
+		return;
+
+	if (aclp->acl_aclp) {
+		acl_size = aclp->acl_cnt * aclp->acl_entry_size;
+		cacl_free(aclp->acl_aclp, acl_size);
+	}
+
+	cacl_free(aclp, sizeof (acl_t));
+}
+
+static uint32_t
+access_mask_set(int haswriteperm, int hasreadperm, int isowner, int isallow)
+{
+	uint32_t access_mask = 0;
+	int acl_produce;
+	int synchronize_set = 0, write_owner_set = 0;
+	int delete_set = 0, write_attrs_set = 0;
+	int read_named_set = 0, write_named_set = 0;
+
+	acl_produce = (ACL_SYNCHRONIZE_SET_ALLOW |
+	    ACL_WRITE_ATTRS_OWNER_SET_ALLOW |
+	    ACL_WRITE_ATTRS_WRITER_SET_DENY);
+
+	if (isallow) {
+		synchronize_set = ACL_SYNCHRONIZE_SET_ALLOW;
+		write_owner_set = ACL_WRITE_OWNER_SET_ALLOW;
+		delete_set = ACL_DELETE_SET_ALLOW;
+		if (hasreadperm)
+			read_named_set = ACL_READ_NAMED_READER_SET_ALLOW;
+		if (haswriteperm)
+			write_named_set = ACL_WRITE_NAMED_WRITER_SET_ALLOW;
+		if (isowner)
+			write_attrs_set = ACL_WRITE_ATTRS_OWNER_SET_ALLOW;
+		else if (haswriteperm)
+			write_attrs_set = ACL_WRITE_ATTRS_WRITER_SET_ALLOW;
+	} else {
+
+		synchronize_set = ACL_SYNCHRONIZE_SET_DENY;
+		write_owner_set = ACL_WRITE_OWNER_SET_DENY;
+		delete_set = ACL_DELETE_SET_DENY;
+		if (hasreadperm)
+			read_named_set = ACL_READ_NAMED_READER_SET_DENY;
+		if (haswriteperm)
+			write_named_set = ACL_WRITE_NAMED_WRITER_SET_DENY;
+		if (isowner)
+			write_attrs_set = ACL_WRITE_ATTRS_OWNER_SET_DENY;
+		else if (haswriteperm)
+			write_attrs_set = ACL_WRITE_ATTRS_WRITER_SET_DENY;
+		else
+			/*
+			 * If the entity is not the owner and does not
+			 * have write permissions ACE_WRITE_ATTRIBUTES will
+			 * always go in the DENY ACE.
+			 */
+			access_mask |= ACE_WRITE_ATTRIBUTES;
+	}
+
+	if (acl_produce & synchronize_set)
+		access_mask |= ACE_SYNCHRONIZE;
+	if (acl_produce & write_owner_set)
+		access_mask |= ACE_WRITE_OWNER;
+	if (acl_produce & delete_set)
+		access_mask |= ACE_DELETE;
+	if (acl_produce & write_attrs_set)
+		access_mask |= ACE_WRITE_ATTRIBUTES;
+	if (acl_produce & read_named_set)
+		access_mask |= ACE_READ_NAMED_ATTRS;
+	if (acl_produce & write_named_set)
+		access_mask |= ACE_WRITE_NAMED_ATTRS;
+
+	return (access_mask);
+}
+
+/*
+ * Given an mode_t, convert it into an access_mask as used
+ * by nfsace, assuming aclent_t -> nfsace semantics.
+ */
+static uint32_t
+mode_to_ace_access(mode_t mode, int isdir, int isowner, int isallow)
+{
+	uint32_t access = 0;
+	int haswriteperm = 0;
+	int hasreadperm = 0;
+
+	if (isallow) {
+		haswriteperm = (mode & S_IWOTH);
+		hasreadperm = (mode & S_IROTH);
+	} else {
+		haswriteperm = !(mode & S_IWOTH);
+		hasreadperm = !(mode & S_IROTH);
+	}
+
+	/*
+	 * The following call takes care of correctly setting the following
+	 * mask bits in the access_mask:
+	 * ACE_SYNCHRONIZE, ACE_WRITE_OWNER, ACE_DELETE,
+	 * ACE_WRITE_ATTRIBUTES, ACE_WRITE_NAMED_ATTRS, ACE_READ_NAMED_ATTRS
+	 */
+	access = access_mask_set(haswriteperm, hasreadperm, isowner, isallow);
+
+	if (isallow) {
+		access |= ACE_READ_ACL | ACE_READ_ATTRIBUTES;
+		if (isowner)
+			access |= ACE_WRITE_ACL;
+	} else {
+		if (! isowner)
+			access |= ACE_WRITE_ACL;
+	}
+
+	/* read */
+	if (mode & S_IROTH) {
+		access |= ACE_READ_DATA;
+	}
+	/* write */
+	if (mode & S_IWOTH) {
+		access |= ACE_WRITE_DATA |
+		    ACE_APPEND_DATA;
+		if (isdir)
+			access |= ACE_DELETE_CHILD;
+	}
+	/* exec */
+	if (mode & 01) {
+		access |= ACE_EXECUTE;
+	}
+
+	return (access);
+}
+
+/*
+ * Given an nfsace (presumably an ALLOW entry), make a
+ * corresponding DENY entry at the address given.
+ */
+static void
+ace_make_deny(ace_t *allow, ace_t *deny, int isdir, int isowner)
+{
+	(void) memcpy(deny, allow, sizeof (ace_t));
+
+	deny->a_who = allow->a_who;
+
+	deny->a_type = ACE_ACCESS_DENIED_ACE_TYPE;
+	deny->a_access_mask ^= ACE_POSIX_SUPPORTED_BITS;
+	if (isdir)
+		deny->a_access_mask ^= ACE_DELETE_CHILD;
+
+	deny->a_access_mask &= ~(ACE_SYNCHRONIZE | ACE_WRITE_OWNER |
+	    ACE_DELETE | ACE_WRITE_ATTRIBUTES | ACE_READ_NAMED_ATTRS |
+	    ACE_WRITE_NAMED_ATTRS);
+	deny->a_access_mask |= access_mask_set((allow->a_access_mask &
+	    ACE_WRITE_DATA), (allow->a_access_mask & ACE_READ_DATA), isowner,
+	    B_FALSE);
+}
+/*
+ * Make an initial pass over an array of aclent_t's.  Gather
+ * information such as an ACL_MASK (if any), number of users,
+ * number of groups, and whether the array needs to be sorted.
+ */
+static int
+ln_aent_preprocess(aclent_t *aclent, int n,
+    int *hasmask, mode_t *mask,
+    int *numuser, int *numgroup, int *needsort)
+{
+	int error = 0;
+	int i;
+	int curtype = 0;
+
+	*hasmask = 0;
+	*mask = 07;
+	*needsort = 0;
+	*numuser = 0;
+	*numgroup = 0;
+
+	for (i = 0; i < n; i++) {
+		if (aclent[i].a_type < curtype)
+			*needsort = 1;
+		else if (aclent[i].a_type > curtype)
+			curtype = aclent[i].a_type;
+		if (aclent[i].a_type & USER)
+			(*numuser)++;
+		if (aclent[i].a_type & (GROUP | GROUP_OBJ))
+			(*numgroup)++;
+		if (aclent[i].a_type & CLASS_OBJ) {
+			if (*hasmask) {
+				error = EINVAL;
+				goto out;
+			} else {
+				*hasmask = 1;
+				*mask = aclent[i].a_perm;
+			}
+		}
+	}
+
+	if ((! *hasmask) && (*numuser + *numgroup > 1)) {
+		error = EINVAL;
+		goto out;
+	}
+
+out:
+	return (error);
+}
+
+/*
+ * Convert an array of aclent_t into an array of nfsace entries,
+ * following POSIX draft -> nfsv4 conversion semantics as outlined in
+ * the IETF draft.
+ */
+static int
+ln_aent_to_ace(aclent_t *aclent, int n, ace_t **acepp, int *rescount, int isdir)
+{
+	int error = 0;
+	mode_t mask;
+	int numuser, numgroup, needsort;
+	int resultsize = 0;
+	int i, groupi = 0, skip;
+	ace_t *acep, *result = NULL;
+	int hasmask;
+
+	error = ln_aent_preprocess(aclent, n, &hasmask, &mask,
+	    &numuser, &numgroup, &needsort);
+	if (error != 0)
+		goto out;
+
+	/* allow + deny for each aclent */
+	resultsize = n * 2;
+	if (hasmask) {
+		/*
+		 * stick extra deny on the group_obj and on each
+		 * user|group for the mask (the group_obj was added
+		 * into the count for numgroup)
+		 */
+		resultsize += numuser + numgroup;
+		/* ... and don't count the mask itself */
+		resultsize -= 2;
+	}
+
+	/* sort the source if necessary */
+	if (needsort)
+		ksort((caddr_t)aclent, n, sizeof (aclent_t), cmp2acls);
+
+	if (cacl_malloc((void **)&result, resultsize * sizeof (ace_t)) != 0)
+		goto out;
+
+	acep = result;
+
+	for (i = 0; i < n; i++) {
+		/*
+		 * don't process CLASS_OBJ (mask); mask was grabbed in
+		 * ln_aent_preprocess()
+		 */
+		if (aclent[i].a_type & CLASS_OBJ)
+			continue;
+
+		/* If we need an ACL_MASK emulator, prepend it now */
+		if ((hasmask) &&
+		    (aclent[i].a_type & (USER | GROUP | GROUP_OBJ))) {
+			acep->a_type = ACE_ACCESS_DENIED_ACE_TYPE;
+			acep->a_flags = 0;
+			if (aclent[i].a_type & GROUP_OBJ) {
+				acep->a_who = (uid_t)-1;
+				acep->a_flags |=
+				    (ACE_IDENTIFIER_GROUP|ACE_GROUP);
+			} else if (aclent[i].a_type & USER) {
+				acep->a_who = aclent[i].a_id;
+			} else {
+				acep->a_who = aclent[i].a_id;
+				acep->a_flags |= ACE_IDENTIFIER_GROUP;
+			}
+			if (aclent[i].a_type & ACL_DEFAULT) {
+				acep->a_flags |= ACE_INHERIT_ONLY_ACE |
+				    ACE_FILE_INHERIT_ACE |
+				    ACE_DIRECTORY_INHERIT_ACE;
+			}
+			/*
+			 * Set the access mask for the prepended deny
+			 * ace.  To do this, we invert the mask (found
+			 * in ln_aent_preprocess()) then convert it to an
+			 * DENY ace access_mask.
+			 */
+			acep->a_access_mask = mode_to_ace_access((mask ^ 07),
+			    isdir, 0, 0);
+			acep += 1;
+		}
+
+		/* handle a_perm -> access_mask */
+		acep->a_access_mask = mode_to_ace_access(aclent[i].a_perm,
+		    isdir, aclent[i].a_type & USER_OBJ, 1);
+
+		/* emulate a default aclent */
+		if (aclent[i].a_type & ACL_DEFAULT) {
+			acep->a_flags |= ACE_INHERIT_ONLY_ACE |
+			    ACE_FILE_INHERIT_ACE |
+			    ACE_DIRECTORY_INHERIT_ACE;
+		}
+
+		/*
+		 * handle a_perm and a_id
+		 *
+		 * this must be done last, since it involves the
+		 * corresponding deny aces, which are handled
+		 * differently for each different a_type.
+		 */
+		if (aclent[i].a_type & USER_OBJ) {
+			acep->a_who = (uid_t)-1;
+			acep->a_flags |= ACE_OWNER;
+			ace_make_deny(acep, acep + 1, isdir, B_TRUE);
+			acep += 2;
+		} else if (aclent[i].a_type & USER) {
+			acep->a_who = aclent[i].a_id;
+			ace_make_deny(acep, acep + 1, isdir, B_FALSE);
+			acep += 2;
+		} else if (aclent[i].a_type & (GROUP_OBJ | GROUP)) {
+			if (aclent[i].a_type & GROUP_OBJ) {
+				acep->a_who = (uid_t)-1;
+				acep->a_flags |= ACE_GROUP;
+			} else {
+				acep->a_who = aclent[i].a_id;
+			}
+			acep->a_flags |= ACE_IDENTIFIER_GROUP;
+			/*
+			 * Set the corresponding deny for the group ace.
+			 *
+			 * The deny aces go after all of the groups, unlike
+			 * everything else, where they immediately follow
+			 * the allow ace.
+			 *
+			 * We calculate "skip", the number of slots to
+			 * skip ahead for the deny ace, here.
+			 *
+			 * The pattern is:
+			 * MD1 A1 MD2 A2 MD3 A3 D1 D2 D3
+			 * thus, skip is
+			 * (2 * numgroup) - 1 - groupi
+			 * (2 * numgroup) to account for MD + A
+			 * - 1 to account for the fact that we're on the
+			 * access (A), not the mask (MD)
+			 * - groupi to account for the fact that we have
+			 * passed up groupi number of MD's.
+			 */
+			skip = (2 * numgroup) - 1 - groupi;
+			ace_make_deny(acep, acep + skip, isdir, B_FALSE);
+			/*
+			 * If we just did the last group, skip acep past
+			 * all of the denies; else, just move ahead one.
+			 */
+			if (++groupi >= numgroup)
+				acep += numgroup + 1;
+			else
+				acep += 1;
+		} else if (aclent[i].a_type & OTHER_OBJ) {
+			acep->a_who = (uid_t)-1;
+			acep->a_flags |= ACE_EVERYONE;
+			ace_make_deny(acep, acep + 1, isdir, B_FALSE);
+			acep += 2;
+		} else {
+			error = EINVAL;
+			goto out;
+		}
+	}
+
+	*acepp = result;
+	*rescount = resultsize;
+
+out:
+	if (error != 0) {
+		if ((result != NULL) && (resultsize > 0)) {
+			cacl_free(result, resultsize * sizeof (ace_t));
+		}
+	}
+
+	return (error);
+}
+
+static int
+convert_aent_to_ace(aclent_t *aclentp, int aclcnt, int isdir,
+    ace_t **retacep, int *retacecnt)
+{
+	ace_t *acep;
+	ace_t *dfacep;
+	int acecnt = 0;
+	int dfacecnt = 0;
+	int dfaclstart = 0;
+	int dfaclcnt = 0;
+	aclent_t *aclp;
+	int i;
+	int error;
+	int acesz, dfacesz;
+
+	ksort((caddr_t)aclentp, aclcnt, sizeof (aclent_t), cmp2acls);
+
+	for (i = 0, aclp = aclentp; i < aclcnt; aclp++, i++) {
+		if (aclp->a_type & ACL_DEFAULT)
+			break;
+	}
+
+	if (i < aclcnt) {
+		dfaclstart = i;
+		dfaclcnt = aclcnt - i;
+	}
+
+	if (dfaclcnt && isdir == 0) {
+		return (EINVAL);
+	}
+
+	error = ln_aent_to_ace(aclentp, i,  &acep, &acecnt, isdir);
+	if (error)
+		return (error);
+
+	if (dfaclcnt) {
+		error = ln_aent_to_ace(&aclentp[dfaclstart], dfaclcnt,
+		    &dfacep, &dfacecnt, isdir);
+		if (error) {
+			if (acep) {
+				cacl_free(acep, acecnt * sizeof (ace_t));
+			}
+			return (error);
+		}
+	}
+
+	if (dfacecnt != 0) {
+		acesz = sizeof (ace_t) * acecnt;
+		dfacesz = sizeof (ace_t) * dfacecnt;
+		acep = cacl_realloc(acep, acesz, acesz + dfacesz);
+		if (acep == NULL)
+			return (ENOMEM);
+		if (dfaclcnt) {
+			(void) memcpy(acep + acecnt, dfacep, dfacesz);
+		}
+	}
+	if (dfaclcnt)
+		cacl_free(dfacep, dfacecnt * sizeof (ace_t));
+
+	*retacecnt = acecnt + dfacecnt;
+	*retacep = acep;
+	return (0);
+}
+
+static int
+ace_mask_to_mode(uint32_t  mask, o_mode_t *modep, int isdir)
+{
+	int error = 0;
+	o_mode_t mode = 0;
+	uint32_t bits, wantbits;
+
+	/* read */
+	if (mask & ACE_READ_DATA)
+		mode |= S_IROTH;
+
+	/* write */
+	wantbits = (ACE_WRITE_DATA | ACE_APPEND_DATA);
+	if (isdir)
+		wantbits |= ACE_DELETE_CHILD;
+	bits = mask & wantbits;
+	if (bits != 0) {
+		if (bits != wantbits) {
+			error = ENOTSUP;
+			goto out;
+		}
+		mode |= S_IWOTH;
+	}
+
+	/* exec */
+	if (mask & ACE_EXECUTE) {
+		mode |= S_IXOTH;
+	}
+
+	*modep = mode;
+
+out:
+	return (error);
+}
+
+static void
+acevals_init(acevals_t *vals, uid_t key)
+{
+	bzero(vals, sizeof (*vals));
+	vals->allowed = ACE_MASK_UNDEFINED;
+	vals->denied = ACE_MASK_UNDEFINED;
+	vals->mask = ACE_MASK_UNDEFINED;
+	vals->key = key;
+}
+
+static void
+ace_list_init(ace_list_t *al, int dfacl_flag)
+{
+	acevals_init(&al->user_obj, 0);
+	acevals_init(&al->group_obj, 0);
+	acevals_init(&al->other_obj, 0);
+	al->numusers = 0;
+	al->numgroups = 0;
+	al->acl_mask = 0;
+	al->hasmask = 0;
+	al->state = ace_unused;
+	al->seen = 0;
+	al->dfacl_flag = dfacl_flag;
+}
+
+/*
+ * Find or create an acevals holder for a given id and avl tree.
+ *
+ * Note that only one thread will ever touch these avl trees, so
+ * there is no need for locking.
+ */
+static acevals_t *
+acevals_find(ace_t *ace, avl_tree_t *avl, int *num)
+{
+	acevals_t key, *rc;
+	avl_index_t where;
+
+	key.key = ace->a_who;
+	rc = avl_find(avl, &key, &where);
+	if (rc != NULL)
+		return (rc);
+
+	/* this memory is freed by ln_ace_to_aent()->ace_list_free() */
+	if (cacl_malloc((void **)&rc, sizeof (acevals_t)) != 0)
+		return (NULL);
+
+	acevals_init(rc, ace->a_who);
+	avl_insert(avl, rc, where);
+	(*num)++;
+
+	return (rc);
+}
+
+static int
+access_mask_check(ace_t *acep, int mask_bit, int isowner)
+{
+	int set_deny, err_deny;
+	int set_allow, err_allow;
+	int acl_consume;
+	int haswriteperm, hasreadperm;
+
+	if (acep->a_type == ACE_ACCESS_DENIED_ACE_TYPE) {
+		haswriteperm = (acep->a_access_mask & ACE_WRITE_DATA) ? 0 : 1;
+		hasreadperm = (acep->a_access_mask & ACE_READ_DATA) ? 0 : 1;
+	} else {
+		haswriteperm = (acep->a_access_mask & ACE_WRITE_DATA) ? 1 : 0;
+		hasreadperm = (acep->a_access_mask & ACE_READ_DATA) ? 1 : 0;
+	}
+
+	acl_consume = (ACL_SYNCHRONIZE_ERR_DENY |
+	    ACL_DELETE_ERR_DENY |
+	    ACL_WRITE_OWNER_ERR_DENY |
+	    ACL_WRITE_OWNER_ERR_ALLOW |
+	    ACL_WRITE_ATTRS_OWNER_SET_ALLOW |
+	    ACL_WRITE_ATTRS_OWNER_ERR_DENY |
+	    ACL_WRITE_ATTRS_WRITER_SET_DENY |
+	    ACL_WRITE_ATTRS_WRITER_ERR_ALLOW |
+	    ACL_WRITE_NAMED_WRITER_ERR_DENY |
+	    ACL_READ_NAMED_READER_ERR_DENY);
+
+	if (mask_bit == ACE_SYNCHRONIZE) {
+		set_deny = ACL_SYNCHRONIZE_SET_DENY;
+		err_deny =  ACL_SYNCHRONIZE_ERR_DENY;
+		set_allow = ACL_SYNCHRONIZE_SET_ALLOW;
+		err_allow = ACL_SYNCHRONIZE_ERR_ALLOW;
+	} else if (mask_bit == ACE_WRITE_OWNER) {
+		set_deny = ACL_WRITE_OWNER_SET_DENY;
+		err_deny =  ACL_WRITE_OWNER_ERR_DENY;
+		set_allow = ACL_WRITE_OWNER_SET_ALLOW;
+		err_allow = ACL_WRITE_OWNER_ERR_ALLOW;
+	} else if (mask_bit == ACE_DELETE) {
+		set_deny = ACL_DELETE_SET_DENY;
+		err_deny =  ACL_DELETE_ERR_DENY;
+		set_allow = ACL_DELETE_SET_ALLOW;
+		err_allow = ACL_DELETE_ERR_ALLOW;
+	} else if (mask_bit == ACE_WRITE_ATTRIBUTES) {
+		if (isowner) {
+			set_deny = ACL_WRITE_ATTRS_OWNER_SET_DENY;
+			err_deny =  ACL_WRITE_ATTRS_OWNER_ERR_DENY;
+			set_allow = ACL_WRITE_ATTRS_OWNER_SET_ALLOW;
+			err_allow = ACL_WRITE_ATTRS_OWNER_ERR_ALLOW;
+		} else if (haswriteperm) {
+			set_deny = ACL_WRITE_ATTRS_WRITER_SET_DENY;
+			err_deny =  ACL_WRITE_ATTRS_WRITER_ERR_DENY;
+			set_allow = ACL_WRITE_ATTRS_WRITER_SET_ALLOW;
+			err_allow = ACL_WRITE_ATTRS_WRITER_ERR_ALLOW;
+		} else {
+			if ((acep->a_access_mask & mask_bit) &&
+			    (acep->a_type & ACE_ACCESS_ALLOWED_ACE_TYPE)) {
+				return (ENOTSUP);
+			}
+			return (0);
+		}
+	} else if (mask_bit == ACE_READ_NAMED_ATTRS) {
+		if (!hasreadperm)
+			return (0);
+
+		set_deny = ACL_READ_NAMED_READER_SET_DENY;
+		err_deny = ACL_READ_NAMED_READER_ERR_DENY;
+		set_allow = ACL_READ_NAMED_READER_SET_ALLOW;
+		err_allow = ACL_READ_NAMED_READER_ERR_ALLOW;
+	} else if (mask_bit == ACE_WRITE_NAMED_ATTRS) {
+		if (!haswriteperm)
+			return (0);
+
+		set_deny = ACL_WRITE_NAMED_WRITER_SET_DENY;
+		err_deny = ACL_WRITE_NAMED_WRITER_ERR_DENY;
+		set_allow = ACL_WRITE_NAMED_WRITER_SET_ALLOW;
+		err_allow = ACL_WRITE_NAMED_WRITER_ERR_ALLOW;
+	} else {
+		return (EINVAL);
+	}
+
+	if (acep->a_type == ACE_ACCESS_DENIED_ACE_TYPE) {
+		if (acl_consume & set_deny) {
+			if (!(acep->a_access_mask & mask_bit)) {
+				return (ENOTSUP);
+			}
+		} else if (acl_consume & err_deny) {
+			if (acep->a_access_mask & mask_bit) {
+				return (ENOTSUP);
+			}
+		}
+	} else {
+		/* ACE_ACCESS_ALLOWED_ACE_TYPE */
+		if (acl_consume & set_allow) {
+			if (!(acep->a_access_mask & mask_bit)) {
+				return (ENOTSUP);
+			}
+		} else if (acl_consume & err_allow) {
+			if (acep->a_access_mask & mask_bit) {
+				return (ENOTSUP);
+			}
+		}
+	}
+	return (0);
+}
+
+static int
+ace_to_aent_legal(ace_t *acep)
+{
+	int error = 0;
+	int isowner;
+
+	/* only ALLOW or DENY */
+	if ((acep->a_type != ACE_ACCESS_ALLOWED_ACE_TYPE) &&
+	    (acep->a_type != ACE_ACCESS_DENIED_ACE_TYPE)) {
+		error = ENOTSUP;
+		goto out;
+	}
+
+	/* check for invalid flags */
+	if (acep->a_flags & ~(ACE_VALID_FLAG_BITS)) {
+		error = EINVAL;
+		goto out;
+	}
+
+	/* some flags are illegal */
+	if (acep->a_flags & (ACE_SUCCESSFUL_ACCESS_ACE_FLAG |
+	    ACE_FAILED_ACCESS_ACE_FLAG |
+	    ACE_NO_PROPAGATE_INHERIT_ACE)) {
+		error = ENOTSUP;
+		goto out;
+	}
+
+	/* check for invalid masks */
+	if (acep->a_access_mask & ~(ACE_VALID_MASK_BITS)) {
+		error = EINVAL;
+		goto out;
+	}
+
+	if ((acep->a_flags & ACE_OWNER)) {
+		isowner = 1;
+	} else {
+		isowner = 0;
+	}
+
+	error = access_mask_check(acep, ACE_SYNCHRONIZE, isowner);
+	if (error)
+		goto out;
+
+	error = access_mask_check(acep, ACE_WRITE_OWNER, isowner);
+	if (error)
+		goto out;
+
+	error = access_mask_check(acep, ACE_DELETE, isowner);
+	if (error)
+		goto out;
+
+	error = access_mask_check(acep, ACE_WRITE_ATTRIBUTES, isowner);
+	if (error)
+		goto out;
+
+	error = access_mask_check(acep, ACE_READ_NAMED_ATTRS, isowner);
+	if (error)
+		goto out;
+
+	error = access_mask_check(acep, ACE_WRITE_NAMED_ATTRS, isowner);
+	if (error)
+		goto out;
+
+	/* more detailed checking of masks */
+	if (acep->a_type == ACE_ACCESS_ALLOWED_ACE_TYPE) {
+		if (! (acep->a_access_mask & ACE_READ_ATTRIBUTES)) {
+			error = ENOTSUP;
+			goto out;
+		}
+		if ((acep->a_access_mask & ACE_WRITE_DATA) &&
+		    (! (acep->a_access_mask & ACE_APPEND_DATA))) {
+			error = ENOTSUP;
+			goto out;
+		}
+		if ((! (acep->a_access_mask & ACE_WRITE_DATA)) &&
+		    (acep->a_access_mask & ACE_APPEND_DATA)) {
+			error = ENOTSUP;
+			goto out;
+		}
+	}
+
+	/* ACL enforcement */
+	if ((acep->a_access_mask & ACE_READ_ACL) &&
+	    (acep->a_type != ACE_ACCESS_ALLOWED_ACE_TYPE)) {
+		error = ENOTSUP;
+		goto out;
+	}
+	if (acep->a_access_mask & ACE_WRITE_ACL) {
+		if ((acep->a_type == ACE_ACCESS_DENIED_ACE_TYPE) &&
+		    (isowner)) {
+			error = ENOTSUP;
+			goto out;
+		}
+		if ((acep->a_type == ACE_ACCESS_ALLOWED_ACE_TYPE) &&
+		    (! isowner)) {
+			error = ENOTSUP;
+			goto out;
+		}
+	}
+
+out:
+	return (error);
+}
+
+static int
+ace_allow_to_mode(uint32_t mask, o_mode_t *modep, int isdir)
+{
+	/* ACE_READ_ACL and ACE_READ_ATTRIBUTES must both be set */
+	if ((mask & (ACE_READ_ACL | ACE_READ_ATTRIBUTES)) !=
+	    (ACE_READ_ACL | ACE_READ_ATTRIBUTES)) {
+		return (ENOTSUP);
+	}
+
+	return (ace_mask_to_mode(mask, modep, isdir));
+}
+
+static int
+acevals_to_aent(acevals_t *vals, aclent_t *dest, ace_list_t *list,
+    uid_t owner, gid_t group, int isdir)
+{
+	int error;
+	uint32_t  flips = ACE_POSIX_SUPPORTED_BITS;
+
+	if (isdir)
+		flips |= ACE_DELETE_CHILD;
+	if (vals->allowed != (vals->denied ^ flips)) {
+		error = ENOTSUP;
+		goto out;
+	}
+	if ((list->hasmask) && (list->acl_mask != vals->mask) &&
+	    (vals->aent_type & (USER | GROUP | GROUP_OBJ))) {
+		error = ENOTSUP;
+		goto out;
+	}
+	error = ace_allow_to_mode(vals->allowed, &dest->a_perm, isdir);
+	if (error != 0)
+		goto out;
+	dest->a_type = vals->aent_type;
+	if (dest->a_type & (USER | GROUP)) {
+		dest->a_id = vals->key;
+	} else if (dest->a_type & USER_OBJ) {
+		dest->a_id = owner;
+	} else if (dest->a_type & GROUP_OBJ) {
+		dest->a_id = group;
+	} else if (dest->a_type & OTHER_OBJ) {
+		dest->a_id = 0;
+	} else {
+		error = EINVAL;
+		goto out;
+	}
+
+out:
+	return (error);
+}
+
+
+static int
+ace_list_to_aent(ace_list_t *list, aclent_t **aclentp, int *aclcnt,
+    uid_t owner, gid_t group, int isdir)
+{
+	int error = 0;
+	aclent_t *aent, *result = NULL;
+	acevals_t *vals;
+	int resultcount;
+
+	if ((list->seen & (USER_OBJ | GROUP_OBJ | OTHER_OBJ)) !=
+	    (USER_OBJ | GROUP_OBJ | OTHER_OBJ)) {
+		error = ENOTSUP;
+		goto out;
+	}
+	if ((! list->hasmask) && (list->numusers + list->numgroups > 0)) {
+		error = ENOTSUP;
+		goto out;
+	}
+
+	resultcount = 3 + list->numusers + list->numgroups;
+	/*
+	 * This must be the same condition as below, when we add the CLASS_OBJ
+	 * (aka ACL mask)
+	 */
+	if ((list->hasmask) || (! list->dfacl_flag))
+		resultcount += 1;
+
+	if (cacl_malloc((void **)&result,
+	    resultcount * sizeof (aclent_t)) != 0) {
+		error = ENOMEM;
+		goto out;
+	}
+	aent = result;
+
+	/* USER_OBJ */
+	if (!(list->user_obj.aent_type & USER_OBJ)) {
+		error = EINVAL;
+		goto out;
+	}
+
+	error = acevals_to_aent(&list->user_obj, aent, list, owner, group,
+	    isdir);
+
+	if (error != 0)
+		goto out;
+	++aent;
+	/* USER */
+	vals = NULL;
+	for (vals = avl_first(&list->user); vals != NULL;
+	    vals = AVL_NEXT(&list->user, vals)) {
+		if (!(vals->aent_type & USER)) {
+			error = EINVAL;
+			goto out;
+		}
+		error = acevals_to_aent(vals, aent, list, owner, group,
+		    isdir);
+		if (error != 0)
+			goto out;
+		++aent;
+	}
+	/* GROUP_OBJ */
+	if (!(list->group_obj.aent_type & GROUP_OBJ)) {
+		error = EINVAL;
+		goto out;
+	}
+	error = acevals_to_aent(&list->group_obj, aent, list, owner, group,
+	    isdir);
+	if (error != 0)
+		goto out;
+	++aent;
+	/* GROUP */
+	vals = NULL;
+	for (vals = avl_first(&list->group); vals != NULL;
+	    vals = AVL_NEXT(&list->group, vals)) {
+		if (!(vals->aent_type & GROUP)) {
+			error = EINVAL;
+			goto out;
+		}
+		error = acevals_to_aent(vals, aent, list, owner, group,
+		    isdir);
+		if (error != 0)
+			goto out;
+		++aent;
+	}
+	/*
+	 * CLASS_OBJ (aka ACL_MASK)
+	 *
+	 * An ACL_MASK is not fabricated if the ACL is a default ACL.
+	 * This is to follow UFS's behavior.
+	 */
+	if ((list->hasmask) || (! list->dfacl_flag)) {
+		if (list->hasmask) {
+			uint32_t flips = ACE_POSIX_SUPPORTED_BITS;
+			if (isdir)
+				flips |= ACE_DELETE_CHILD;
+			error = ace_mask_to_mode(list->acl_mask ^ flips,
+			    &aent->a_perm, isdir);
+			if (error != 0)
+				goto out;
+		} else {
+			/* fabricate the ACL_MASK from the group permissions */
+			error = ace_mask_to_mode(list->group_obj.allowed,
+			    &aent->a_perm, isdir);
+			if (error != 0)
+				goto out;
+		}
+		aent->a_id = 0;
+		aent->a_type = CLASS_OBJ | list->dfacl_flag;
+		++aent;
+	}
+	/* OTHER_OBJ */
+	if (!(list->other_obj.aent_type & OTHER_OBJ)) {
+		error = EINVAL;
+		goto out;
+	}
+	error = acevals_to_aent(&list->other_obj, aent, list, owner, group,
+	    isdir);
+	if (error != 0)
+		goto out;
+	++aent;
+
+	*aclentp = result;
+	*aclcnt = resultcount;
+
+out:
+	if (error != 0) {
+		if (result != NULL)
+			cacl_free(result, resultcount * sizeof (aclent_t));
+	}
+
+	return (error);
+}
+
+
+/*
+ * free all data associated with an ace_list
+ */
+static void
+ace_list_free(ace_list_t *al)
+{
+	acevals_t *node;
+	void *cookie;
+
+	if (al == NULL)
+		return;
+
+	cookie = NULL;
+	while ((node = avl_destroy_nodes(&al->user, &cookie)) != NULL)
+		cacl_free(node, sizeof (acevals_t));
+	cookie = NULL;
+	while ((node = avl_destroy_nodes(&al->group, &cookie)) != NULL)
+		cacl_free(node, sizeof (acevals_t));
+
+	avl_destroy(&al->user);
+	avl_destroy(&al->group);
+
+	/* free the container itself */
+	cacl_free(al, sizeof (ace_list_t));
+}
+
+static int
+acevals_compare(const void *va, const void *vb)
+{
+	const acevals_t *a = va, *b = vb;
+
+	if (a->key == b->key)
+		return (0);
+
+	if (a->key > b->key)
+		return (1);
+
+	else
+		return (-1);
+}
+
+/*
+ * Convert a list of ace_t entries to equivalent regular and default
+ * aclent_t lists.  Return error (ENOTSUP) when conversion is not possible.
+ */
+static int
+ln_ace_to_aent(ace_t *ace, int n, uid_t owner, gid_t group,
+    aclent_t **aclentp, int *aclcnt, aclent_t **dfaclentp, int *dfaclcnt,
+    int isdir)
+{
+	int error = 0;
+	ace_t *acep;
+	uint32_t bits;
+	int i;
+	ace_list_t *normacl = NULL, *dfacl = NULL, *acl;
+	acevals_t *vals;
+
+	*aclentp = NULL;
+	*aclcnt = 0;
+	*dfaclentp = NULL;
+	*dfaclcnt = 0;
+
+	/* we need at least user_obj, group_obj, and other_obj */
+	if (n < 6) {
+		error = ENOTSUP;
+		goto out;
+	}
+	if (ace == NULL) {
+		error = EINVAL;
+		goto out;
+	}
+
+	error = cacl_malloc((void **)&normacl, sizeof (ace_list_t));
+	if (error != 0)
+		goto out;
+
+	avl_create(&normacl->user, acevals_compare, sizeof (acevals_t),
+	    offsetof(acevals_t, avl));
+	avl_create(&normacl->group, acevals_compare, sizeof (acevals_t),
+	    offsetof(acevals_t, avl));
+
+	ace_list_init(normacl, 0);
+
+	error = cacl_malloc((void **)&dfacl, sizeof (ace_list_t));
+	if (error != 0)
+		goto out;
+
+	avl_create(&dfacl->user, acevals_compare, sizeof (acevals_t),
+	    offsetof(acevals_t, avl));
+	avl_create(&dfacl->group, acevals_compare, sizeof (acevals_t),
+	    offsetof(acevals_t, avl));
+	ace_list_init(dfacl, ACL_DEFAULT);
+
+	/* process every ace_t... */
+	for (i = 0; i < n; i++) {
+		acep = &ace[i];
+
+		/* rule out certain cases quickly */
+		error = ace_to_aent_legal(acep);
+		if (error != 0)
+			goto out;
+
+		/*
+		 * Turn off these bits in order to not have to worry about
+		 * them when doing the checks for compliments.
+		 */
+		acep->a_access_mask &= ~(ACE_WRITE_OWNER | ACE_DELETE |
+		    ACE_SYNCHRONIZE | ACE_WRITE_ATTRIBUTES |
+		    ACE_READ_NAMED_ATTRS | ACE_WRITE_NAMED_ATTRS);
+
+		/* see if this should be a regular or default acl */
+		bits = acep->a_flags &
+		    (ACE_INHERIT_ONLY_ACE |
+		    ACE_FILE_INHERIT_ACE |
+		    ACE_DIRECTORY_INHERIT_ACE);
+		if (bits != 0) {
+			/* all or nothing on these inherit bits */
+			if (bits != (ACE_INHERIT_ONLY_ACE |
+			    ACE_FILE_INHERIT_ACE |
+			    ACE_DIRECTORY_INHERIT_ACE)) {
+				error = ENOTSUP;
+				goto out;
+			}
+			acl = dfacl;
+		} else {
+			acl = normacl;
+		}
+
+		if ((acep->a_flags & ACE_OWNER)) {
+			if (acl->state > ace_user_obj) {
+				error = ENOTSUP;
+				goto out;
+			}
+			acl->state = ace_user_obj;
+			acl->seen |= USER_OBJ;
+			vals = &acl->user_obj;
+			vals->aent_type = USER_OBJ | acl->dfacl_flag;
+		} else if ((acep->a_flags & ACE_EVERYONE)) {
+			acl->state = ace_other_obj;
+			acl->seen |= OTHER_OBJ;
+			vals = &acl->other_obj;
+			vals->aent_type = OTHER_OBJ | acl->dfacl_flag;
+		} else if (acep->a_flags & ACE_IDENTIFIER_GROUP) {
+			if (acl->state > ace_group) {
+				error = ENOTSUP;
+				goto out;
+			}
+			if ((acep->a_flags & ACE_GROUP)) {
+				acl->seen |= GROUP_OBJ;
+				vals = &acl->group_obj;
+				vals->aent_type = GROUP_OBJ | acl->dfacl_flag;
+			} else {
+				acl->seen |= GROUP;
+				vals = acevals_find(acep, &acl->group,
+				    &acl->numgroups);
+				if (vals == NULL) {
+					error = ENOMEM;
+					goto out;
+				}
+				vals->aent_type = GROUP | acl->dfacl_flag;
+			}
+			acl->state = ace_group;
+		} else {
+			if (acl->state > ace_user) {
+				error = ENOTSUP;
+				goto out;
+			}
+			acl->state = ace_user;
+			acl->seen |= USER;
+			vals = acevals_find(acep, &acl->user,
+			    &acl->numusers);
+			if (vals == NULL) {
+				error = ENOMEM;
+				goto out;
+			}
+			vals->aent_type = USER | acl->dfacl_flag;
+		}
+
+		if (!(acl->state > ace_unused)) {
+			error = EINVAL;
+			goto out;
+		}
+
+		if (acep->a_type == ACE_ACCESS_ALLOWED_ACE_TYPE) {
+			/* no more than one allowed per aclent_t */
+			if (vals->allowed != ACE_MASK_UNDEFINED) {
+				error = ENOTSUP;
+				goto out;
+			}
+			vals->allowed = acep->a_access_mask;
+		} else {
+			/*
+			 * it's a DENY; if there was a previous DENY, it
+			 * must have been an ACL_MASK.
+			 */
+			if (vals->denied != ACE_MASK_UNDEFINED) {
+				/* ACL_MASK is for USER and GROUP only */
+				if ((acl->state != ace_user) &&
+				    (acl->state != ace_group)) {
+					error = ENOTSUP;
+					goto out;
+				}
+
+				if (! acl->hasmask) {
+					acl->hasmask = 1;
+					acl->acl_mask = vals->denied;
+				/* check for mismatched ACL_MASK emulations */
+				} else if (acl->acl_mask != vals->denied) {
+					error = ENOTSUP;
+					goto out;
+				}
+				vals->mask = vals->denied;
+			}
+			vals->denied = acep->a_access_mask;
+		}
+	}
+
+	/* done collating; produce the aclent_t lists */
+	if (normacl->state != ace_unused) {
+		error = ace_list_to_aent(normacl, aclentp, aclcnt,
+		    owner, group, isdir);
+		if (error != 0) {
+			goto out;
+		}
+	}
+	if (dfacl->state != ace_unused) {
+		error = ace_list_to_aent(dfacl, dfaclentp, dfaclcnt,
+		    owner, group, isdir);
+		if (error != 0) {
+			goto out;
+		}
+	}
+
+out:
+	if (normacl != NULL)
+		ace_list_free(normacl);
+	if (dfacl != NULL)
+		ace_list_free(dfacl);
+
+	return (error);
+}
+
+static int
+convert_ace_to_aent(ace_t *acebufp, int acecnt, int isdir,
+    uid_t owner, gid_t group, aclent_t **retaclentp, int *retaclcnt)
+{
+	int error = 0;
+	aclent_t *aclentp, *dfaclentp;
+	int aclcnt, dfaclcnt;
+	int aclsz, dfaclsz;
+
+	error = ln_ace_to_aent(acebufp, acecnt, owner, group,
+	    &aclentp, &aclcnt, &dfaclentp, &dfaclcnt, isdir);
+
+	if (error)
+		return (error);
+
+
+	if (dfaclcnt != 0) {
+		/*
+		 * Slap aclentp and dfaclentp into a single array.
+		 */
+		aclsz = sizeof (aclent_t) * aclcnt;
+		dfaclsz = sizeof (aclent_t) * dfaclcnt;
+		aclentp = cacl_realloc(aclentp, aclsz, aclsz + dfaclsz);
+		if (aclentp != NULL) {
+			(void) memcpy(aclentp + aclcnt, dfaclentp, dfaclsz);
+		} else {
+			error = ENOMEM;
+		}
+	}
+
+	if (aclentp) {
+		*retaclentp = aclentp;
+		*retaclcnt = aclcnt + dfaclcnt;
+	}
+
+	if (dfaclentp)
+		cacl_free(dfaclentp, dfaclsz);
+
+	return (error);
+}
+
+
+int
+acl_translate(acl_t *aclp, int target_flavor, int isdir, uid_t owner,
+    gid_t group)
+{
+	int aclcnt;
+	void *acldata;
+	int error;
+
+	/*
+	 * See if we need to translate
+	 */
+	if ((target_flavor == _ACL_ACE_ENABLED && aclp->acl_type == ACE_T) ||
+	    (target_flavor == _ACL_ACLENT_ENABLED &&
+	    aclp->acl_type == ACLENT_T))
+		return (0);
+
+	if (target_flavor == -1) {
+		error = EINVAL;
+		goto out;
+	}
+
+	if (target_flavor ==  _ACL_ACE_ENABLED &&
+	    aclp->acl_type == ACLENT_T) {
+		error = convert_aent_to_ace(aclp->acl_aclp,
+		    aclp->acl_cnt, isdir, (ace_t **)&acldata, &aclcnt);
+		if (error)
+			goto out;
+
+	} else if (target_flavor == _ACL_ACLENT_ENABLED &&
+	    aclp->acl_type == ACE_T) {
+		error = convert_ace_to_aent(aclp->acl_aclp, aclp->acl_cnt,
+		    isdir, owner, group, (aclent_t **)&acldata, &aclcnt);
+		if (error)
+			goto out;
+	} else {
+		error = ENOTSUP;
+		goto out;
+	}
+
+	/*
+	 * replace old acl with newly translated acl
+	 */
+	cacl_free(aclp->acl_aclp, aclp->acl_cnt * aclp->acl_entry_size);
+	aclp->acl_aclp = acldata;
+	aclp->acl_cnt = aclcnt;
+	if (target_flavor == _ACL_ACE_ENABLED) {
+		aclp->acl_type = ACE_T;
+		aclp->acl_entry_size = sizeof (ace_t);
+	} else {
+		aclp->acl_type = ACLENT_T;
+		aclp->acl_entry_size = sizeof (aclent_t);
+	}
+	return (0);
+
+out:
+
+#if !defined(_KERNEL)
+	errno = error;
+	return (-1);
+#else
+	return (error);
+#endif
+}
diff --git a/sys/cddl/contrib/opensolaris/common/acl/acl_common.h b/sys/cddl/contrib/opensolaris/common/acl/acl_common.h
index 2227ad77ea93..84bd04f52fd6 100644
--- a/sys/cddl/contrib/opensolaris/common/acl/acl_common.h
+++ b/sys/cddl/contrib/opensolaris/common/acl/acl_common.h
@@ -2,9 +2,8 @@
  * CDDL HEADER START
  *
  * The contents of this file are subject to the terms of the
- * Common Development and Distribution License, Version 1.0 only
- * (the "License").  You may not use this file except in compliance
- * with the License.
+ * Common Development and Distribution License (the "License").
+ * You may not use this file except in compliance with the License.
  *
  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
  * or http://www.opensolaris.org/os/licensing.
@@ -20,12 +19,12 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
-#ifndef	_ACL_ACL_UTILS_H
-#define	_ACL_ACL_UTILS_H
+#ifndef	_ACL_COMMON_H
+#define	_ACL_COMMON_H
 
 #pragma ident	"%Z%%M%	%I%	%E% SMI"
 
@@ -34,7 +33,7 @@
 #include <sys/acl.h>
 #include <sys/stat.h>
 
-#ifdef  __cplusplus
+#ifdef	__cplusplus
 extern "C" {
 #endif
 
@@ -42,15 +41,21 @@ extern ace_t trivial_acl[6];
 
 extern int acltrivial(const char *);
 extern void adjust_ace_pair(ace_t *pair, mode_t mode);
+extern void adjust_ace_pair_common(void *, size_t, size_t, mode_t);
 extern int ace_trivial(ace_t *acep, int aclcnt);
+extern int ace_trivial_common(void *, int,
+    uint64_t (*walk)(void *, uint64_t, int aclcnt, uint16_t *, uint16_t *,
+    uint32_t *mask));
+extern acl_t *acl_alloc(acl_type_t);
+extern void acl_free(acl_t *aclp);
+extern int acl_translate(acl_t *aclp, int target_flavor,
+    int isdir, uid_t owner, gid_t group);
 void ksort(caddr_t v, int n, int s, int (*f)());
 int cmp2acls(void *a, void *b);
 
 
-
-
-#ifdef  __cplusplus
+#ifdef	__cplusplus
 }
 #endif
 
-#endif /* _ACL_ACL_UTILS_H */
+#endif /* _ACL_COMMON_H */
diff --git a/sys/cddl/contrib/opensolaris/common/atomic/amd64/atomic.S b/sys/cddl/contrib/opensolaris/common/atomic/amd64/atomic.S
index 2e62aa420d91..6851086c1f96 100644
--- a/sys/cddl/contrib/opensolaris/common/atomic/amd64/atomic.S
+++ b/sys/cddl/contrib/opensolaris/common/atomic/amd64/atomic.S
@@ -2,9 +2,8 @@
  * CDDL HEADER START
  *
  * The contents of this file are subject to the terms of the
- * Common Development and Distribution License, Version 1.0 only
- * (the "License").  You may not use this file except in compliance
- * with the License.
+ * Common Development and Distribution License (the "License").
+ * You may not use this file except in compliance with the License.
  *
  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
  * or http://www.opensolaris.org/os/licensing.
@@ -19,14 +18,13 @@
  *
  * CDDL HEADER END
  */
+
 /*
- * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
-	.ident	"%Z%%M%	%I%	%E% SMI"
-
-	.file	"%M%"
+	.file	"atomic.s"
 
 #define	_ASM
 #include <sys/asm_linkage.h>
diff --git a/sys/cddl/contrib/opensolaris/common/atomic/i386/atomic.S b/sys/cddl/contrib/opensolaris/common/atomic/i386/atomic.S
index bc7f22acc8d4..57f7d0a47b53 100644
--- a/sys/cddl/contrib/opensolaris/common/atomic/i386/atomic.S
+++ b/sys/cddl/contrib/opensolaris/common/atomic/i386/atomic.S
@@ -2,9 +2,8 @@
  * CDDL HEADER START
  *
  * The contents of this file are subject to the terms of the
- * Common Development and Distribution License, Version 1.0 only
- * (the "License").  You may not use this file except in compliance
- * with the License.
+ * Common Development and Distribution License (the "License").
+ * You may not use this file except in compliance with the License.
  *
  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
  * or http://www.opensolaris.org/os/licensing.
@@ -19,18 +18,54 @@
  *
  * CDDL HEADER END
  */
+
 /*
- * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
-	.ident	"%Z%%M%	%I%	%E% SMI"
-
-	.file	"%M%"
+	.file	"atomic.s"
 
 #define	_ASM
 #include <sys/asm_linkage.h>
 
+	/*
+	 * NOTE: If atomic_dec_64 and atomic_dec_64_nv are ever
+	 * separated, it is important to edit the libc i386 platform
+	 * specific mapfile and remove the NODYNSORT attribute
+	 * from atomic_dec_64_nv.
+	 */
+	ENTRY(atomic_dec_64)
+	ALTENTRY(atomic_dec_64_nv)
+	pushl	%edi
+	pushl	%ebx
+	movl	12(%esp), %edi	// %edi = target address
+	movl	(%edi), %eax
+	movl	4(%edi), %edx	// %edx:%eax = old value
+1:
+	xorl	%ebx, %ebx
+	xorl	%ecx, %ecx
+	not	%ecx
+	not	%ebx		// %ecx:%ebx = -1
+	addl	%eax, %ebx
+	adcl	%edx, %ecx	// add in the carry from inc
+	lock
+	cmpxchg8b (%edi)	// try to stick it in
+	jne	1b
+	movl	%ebx, %eax
+	movl	%ecx, %edx	// return new value
+	popl	%ebx
+	popl	%edi
+	ret
+	SET_SIZE(atomic_dec_64_nv)
+	SET_SIZE(atomic_dec_64)
+
+	/*
+	 * NOTE: If atomic_add_64 and atomic_add_64_nv are ever
+	 * separated, it is important to edit the libc i386 platform
+	 * specific mapfile and remove the NODYNSORT attribute
+	 * from atomic_add_64_nv.
+	 */
 	ENTRY(atomic_add_64)
 	ALTENTRY(atomic_add_64_nv)
 	pushl	%edi
diff --git a/sys/cddl/contrib/opensolaris/common/avl/avl.c b/sys/cddl/contrib/opensolaris/common/avl/avl.c
index 1fa2236607bf..01aa3cb2fa9d 100644
--- a/sys/cddl/contrib/opensolaris/common/avl/avl.c
+++ b/sys/cddl/contrib/opensolaris/common/avl/avl.c
@@ -19,7 +19,7 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
@@ -808,6 +808,64 @@ avl_remove(avl_tree_t *tree, void *data)
 	} while (parent != NULL);
 }
 
+#define	AVL_REINSERT(tree, obj)		\
+	avl_remove((tree), (obj));	\
+	avl_add((tree), (obj))
+
+boolean_t
+avl_update_lt(avl_tree_t *t, void *obj)
+{
+	void *neighbor;
+
+	ASSERT(((neighbor = AVL_NEXT(t, obj)) == NULL) ||
+	    (t->avl_compar(obj, neighbor) <= 0));
+
+	neighbor = AVL_PREV(t, obj);
+	if ((neighbor != NULL) && (t->avl_compar(obj, neighbor) < 0)) {
+		AVL_REINSERT(t, obj);
+		return (B_TRUE);
+	}
+
+	return (B_FALSE);
+}
+
+boolean_t
+avl_update_gt(avl_tree_t *t, void *obj)
+{
+	void *neighbor;
+
+	ASSERT(((neighbor = AVL_PREV(t, obj)) == NULL) ||
+	    (t->avl_compar(obj, neighbor) >= 0));
+
+	neighbor = AVL_NEXT(t, obj);
+	if ((neighbor != NULL) && (t->avl_compar(obj, neighbor) > 0)) {
+		AVL_REINSERT(t, obj);
+		return (B_TRUE);
+	}
+
+	return (B_FALSE);
+}
+
+boolean_t
+avl_update(avl_tree_t *t, void *obj)
+{
+	void *neighbor;
+
+	neighbor = AVL_PREV(t, obj);
+	if ((neighbor != NULL) && (t->avl_compar(obj, neighbor) < 0)) {
+		AVL_REINSERT(t, obj);
+		return (B_TRUE);
+	}
+
+	neighbor = AVL_NEXT(t, obj);
+	if ((neighbor != NULL) && (t->avl_compar(obj, neighbor) > 0)) {
+		AVL_REINSERT(t, obj);
+		return (B_TRUE);
+	}
+
+	return (B_FALSE);
+}
+
 /*
  * initialize a new AVL tree
  */
@@ -853,6 +911,12 @@ avl_numnodes(avl_tree_t *tree)
 	return (tree->avl_numnodes);
 }
 
+boolean_t
+avl_is_empty(avl_tree_t *tree)
+{
+	ASSERT(tree);
+	return (tree->avl_numnodes == 0);
+}
 
 #define	CHILDBIT	(1L)
 
diff --git a/sys/cddl/contrib/opensolaris/common/nvpair/nvpair.c b/sys/cddl/contrib/opensolaris/common/nvpair/nvpair.c
index d3d5bed525ab..9cdc534ffc1b 100644
--- a/sys/cddl/contrib/opensolaris/common/nvpair/nvpair.c
+++ b/sys/cddl/contrib/opensolaris/common/nvpair/nvpair.c
@@ -20,7 +20,7 @@
  */
 
 /*
- * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
@@ -34,15 +34,17 @@
 
 #if defined(_KERNEL) && !defined(_BOOT)
 #include <sys/varargs.h>
+#include <sys/sunddi.h>
 #else
 #include <stdarg.h>
-#include <strings.h>
+#include <stdlib.h>
+#include <string.h>
 #endif
 
 #ifndef	offsetof
-#define	offsetof(s, m)	((size_t)(&(((s *)0)->m)))
+#define	offsetof(s, m)		((size_t)(&(((s *)0)->m)))
 #endif
-
+#define	skip_whitespace(p)	while ((*(p) == ' ') || (*(p) == '\t')) p++
 
 /*
  * nvpair.c - Provides kernel & userland interfaces for manipulating
@@ -201,7 +203,7 @@ nv_mem_free(nvpriv_t *nvp, void *buf, size_t size)
 static void
 nv_priv_init(nvpriv_t *priv, nv_alloc_t *nva, uint32_t stat)
 {
-	bzero(priv, sizeof (priv));
+	bzero(priv, sizeof (nvpriv_t));
 
 	priv->nvp_nva = nva;
 	priv->nvp_stat = stat;
@@ -395,6 +397,9 @@ i_validate_type_nelem(data_type_t type, uint_t nelem)
 	case DATA_TYPE_STRING:
 	case DATA_TYPE_HRTIME:
 	case DATA_TYPE_NVLIST:
+#if !defined(_KERNEL)
+	case DATA_TYPE_DOUBLE:
+#endif
 		if (nelem != 1)
 			return (EINVAL);
 		break;
@@ -733,6 +738,11 @@ i_get_value_size(data_type_t type, const void *data, uint_t nelem)
 	case DATA_TYPE_UINT64:
 		value_sz = sizeof (uint64_t);
 		break;
+#if !defined(_KERNEL)
+	case DATA_TYPE_DOUBLE:
+		value_sz = sizeof (double);
+		break;
+#endif
 	case DATA_TYPE_STRING:
 		if (data == NULL)
 			value_sz = 0;
@@ -1017,6 +1027,14 @@ nvlist_add_uint64(nvlist_t *nvl, const char *name, uint64_t val)
 	return (nvlist_add_common(nvl, name, DATA_TYPE_UINT64, 1, &val));
 }
 
+#if !defined(_KERNEL)
+int
+nvlist_add_double(nvlist_t *nvl, const char *name, double val)
+{
+	return (nvlist_add_common(nvl, name, DATA_TYPE_DOUBLE, 1, &val));
+}
+#endif
+
 int
 nvlist_add_string(nvlist_t *nvl, const char *name, const char *val)
 {
@@ -1123,13 +1141,15 @@ nvlist_next_nvpair(nvlist_t *nvl, nvpair_t *nvp)
 	curr = NVPAIR2I_NVP(nvp);
 
 	/*
-	 * Ensure that nvp is an valid pointer.
+	 * Ensure that nvp is a valid nvpair on this nvlist.
+	 * NB: nvp_curr is used only as a hint so that we don't always
+	 * have to walk the list to determine if nvp is still on the list.
 	 */
 	if (nvp == NULL)
 		curr = priv->nvp_list;
-	else if (priv->nvp_curr == curr)
+	else if (priv->nvp_curr == curr || nvlist_contains_nvp(nvl, nvp))
 		curr = curr->nvi_next;
-	else if (nvlist_contains_nvp(nvl, nvp) == 0)
+	else
 		curr = NULL;
 
 	priv->nvp_curr = curr;
@@ -1149,6 +1169,27 @@ nvpair_type(nvpair_t *nvp)
 	return (NVP_TYPE(nvp));
 }
 
+int
+nvpair_type_is_array(nvpair_t *nvp)
+{
+	data_type_t type = NVP_TYPE(nvp);
+
+	if ((type == DATA_TYPE_BYTE_ARRAY) ||
+	    (type == DATA_TYPE_UINT8_ARRAY) ||
+	    (type == DATA_TYPE_INT16_ARRAY) ||
+	    (type == DATA_TYPE_UINT16_ARRAY) ||
+	    (type == DATA_TYPE_INT32_ARRAY) ||
+	    (type == DATA_TYPE_UINT32_ARRAY) ||
+	    (type == DATA_TYPE_INT64_ARRAY) ||
+	    (type == DATA_TYPE_UINT64_ARRAY) ||
+	    (type == DATA_TYPE_BOOLEAN_ARRAY) ||
+	    (type == DATA_TYPE_STRING_ARRAY) ||
+	    (type == DATA_TYPE_NVLIST_ARRAY))
+		return (1);
+	return (0);
+
+}
+
 static int
 nvpair_value_common(nvpair_t *nvp, data_type_t type, uint_t *nelem, void *data)
 {
@@ -1176,6 +1217,9 @@ nvpair_value_common(nvpair_t *nvp, data_type_t type, uint_t *nelem, void *data)
 	case DATA_TYPE_INT64:
 	case DATA_TYPE_UINT64:
 	case DATA_TYPE_HRTIME:
+#if !defined(_KERNEL)
+	case DATA_TYPE_DOUBLE:
+#endif
 		if (data == NULL)
 			return (EINVAL);
 		bcopy(NVP_VALUE(nvp), data,
@@ -1312,6 +1356,14 @@ nvlist_lookup_uint64(nvlist_t *nvl, const char *name, uint64_t *val)
 	return (nvlist_lookup_common(nvl, name, DATA_TYPE_UINT64, NULL, val));
 }
 
+#if !defined(_KERNEL)
+int
+nvlist_lookup_double(nvlist_t *nvl, const char *name, double *val)
+{
+	return (nvlist_lookup_common(nvl, name, DATA_TYPE_DOUBLE, NULL, val));
+}
+#endif
+
 int
 nvlist_lookup_string(nvlist_t *nvl, const char *name, char **val)
 {
@@ -1446,6 +1498,9 @@ nvlist_lookup_pairs(nvlist_t *nvl, int flag, ...)
 		case DATA_TYPE_HRTIME:
 		case DATA_TYPE_STRING:
 		case DATA_TYPE_NVLIST:
+#if !defined(_KERNEL)
+		case DATA_TYPE_DOUBLE:
+#endif
 			val = va_arg(ap, void *);
 			ret = nvlist_lookup_common(nvl, name, type, NULL, val);
 			break;
@@ -1479,6 +1534,224 @@ nvlist_lookup_pairs(nvlist_t *nvl, int flag, ...)
 	return (ret);
 }
 
+/*
+ * Find the 'name'ed nvpair in the nvlist 'nvl'. If 'name' found, the function
+ * returns zero and a pointer to the matching nvpair is returned in '*ret'
+ * (given 'ret' is non-NULL). If 'sep' is specified then 'name' will penitrate
+ * multiple levels of embedded nvlists, with 'sep' as the separator. As an
+ * example, if sep is '.', name might look like: "a" or "a.b" or "a.c[3]" or
+ * "a.d[3].e[1]".  This matches the C syntax for array embed (for convience,
+ * code also supports "a.d[3]e[1]" syntax).
+ *
+ * If 'ip' is non-NULL and the last name component is an array, return the
+ * value of the "...[index]" array index in *ip. For an array reference that
+ * is not indexed, *ip will be returned as -1. If there is a syntax error in
+ * 'name', and 'ep' is non-NULL then *ep will be set to point to the location
+ * inside the 'name' string where the syntax error was detected.
+ */
+static int
+nvlist_lookup_nvpair_ei_sep(nvlist_t *nvl, const char *name, const char sep,
+    nvpair_t **ret, int *ip, char **ep)
+{
+	nvpair_t	*nvp;
+	const char	*np;
+	char		*sepp;
+	char		*idxp, *idxep;
+	nvlist_t	**nva;
+	long		idx;
+	int		n;
+
+	if (ip)
+		*ip = -1;			/* not indexed */
+	if (ep)
+		*ep = NULL;
+
+	if ((nvl == NULL) || (name == NULL))
+		return (EINVAL);
+
+	/* step through components of name */
+	for (np = name; np && *np; np = sepp) {
+		/* ensure unique names */
+		if (!(nvl->nvl_nvflag & NV_UNIQUE_NAME))
+			return (ENOTSUP);
+
+		/* skip white space */
+		skip_whitespace(np);
+		if (*np == 0)
+			break;
+
+		/* set 'sepp' to end of current component 'np' */
+		if (sep)
+			sepp = strchr(np, sep);
+		else
+			sepp = NULL;
+
+		/* find start of next "[ index ]..." */
+		idxp = strchr(np, '[');
+
+		/* if sepp comes first, set idxp to NULL */
+		if (sepp && idxp && (sepp < idxp))
+			idxp = NULL;
+
+		/*
+		 * At this point 'idxp' is set if there is an index
+		 * expected for the current component.
+		 */
+		if (idxp) {
+			/* set 'n' to length of current 'np' name component */
+			n = idxp++ - np;
+
+			/* keep sepp up to date for *ep use as we advance */
+			skip_whitespace(idxp);
+			sepp = idxp;
+
+			/* determine the index value */
+#if defined(_KERNEL) && !defined(_BOOT)
+			if (ddi_strtol(idxp, &idxep, 0, &idx))
+				goto fail;
+#else
+			idx = strtol(idxp, &idxep, 0);
+#endif
+			if (idxep == idxp)
+				goto fail;
+
+			/* keep sepp up to date for *ep use as we advance */
+			sepp = idxep;
+
+			/* skip white space index value and check for ']' */
+			skip_whitespace(sepp);
+			if (*sepp++ != ']')
+				goto fail;
+
+			/* for embedded arrays, support C syntax: "a[1].b" */
+			skip_whitespace(sepp);
+			if (sep && (*sepp == sep))
+				sepp++;
+		} else if (sepp) {
+			n = sepp++ - np;
+		} else {
+			n = strlen(np);
+		}
+
+		/* trim trailing whitespace by reducing length of 'np' */
+		if (n == 0)
+			goto fail;
+		for (n--; (np[n] == ' ') || (np[n] == '\t'); n--)
+			;
+		n++;
+
+		/* skip whitespace, and set sepp to NULL if complete */
+		if (sepp) {
+			skip_whitespace(sepp);
+			if (*sepp == 0)
+				sepp = NULL;
+		}
+
+		/*
+		 * At this point:
+		 * o  'n' is the length of current 'np' component.
+		 * o  'idxp' is set if there was an index, and value 'idx'.
+		 * o  'sepp' is set to the beginning of the next component,
+		 *    and set to NULL if we have no more components.
+		 *
+		 * Search for nvpair with matching component name.
+		 */
+		for (nvp = nvlist_next_nvpair(nvl, NULL); nvp != NULL;
+		    nvp = nvlist_next_nvpair(nvl, nvp)) {
+
+			/* continue if no match on name */
+			if (strncmp(np, nvpair_name(nvp), n) ||
+			    (strlen(nvpair_name(nvp)) != n))
+				continue;
+
+			/* if indexed, verify type is array oriented */
+			if (idxp && !nvpair_type_is_array(nvp))
+				goto fail;
+
+			/*
+			 * Full match found, return nvp and idx if this
+			 * was the last component.
+			 */
+			if (sepp == NULL) {
+				if (ret)
+					*ret = nvp;
+				if (ip && idxp)
+					*ip = (int)idx;	/* return index */
+				return (0);		/* found */
+			}
+
+			/*
+			 * More components: current match must be
+			 * of DATA_TYPE_NVLIST or DATA_TYPE_NVLIST_ARRAY
+			 * to support going deeper.
+			 */
+			if (nvpair_type(nvp) == DATA_TYPE_NVLIST) {
+				nvl = EMBEDDED_NVL(nvp);
+				break;
+			} else if (nvpair_type(nvp) == DATA_TYPE_NVLIST_ARRAY) {
+				(void) nvpair_value_nvlist_array(nvp,
+				    &nva, (uint_t *)&n);
+				if ((n < 0) || (idx >= n))
+					goto fail;
+				nvl = nva[idx];
+				break;
+			}
+
+			/* type does not support more levels */
+			goto fail;
+		}
+		if (nvp == NULL)
+			goto fail;		/* 'name' not found */
+
+		/* search for match of next component in embedded 'nvl' list */
+	}
+
+fail:	if (ep && sepp)
+		*ep = sepp;
+	return (EINVAL);
+}
+
+/*
+ * Return pointer to nvpair with specified 'name'.
+ */
+int
+nvlist_lookup_nvpair(nvlist_t *nvl, const char *name, nvpair_t **ret)
+{
+	return (nvlist_lookup_nvpair_ei_sep(nvl, name, 0, ret, NULL, NULL));
+}
+
+/*
+ * Determine if named nvpair exists in nvlist (use embedded separator of '.'
+ * and return array index).  See nvlist_lookup_nvpair_ei_sep for more detailed
+ * description.
+ */
+int nvlist_lookup_nvpair_embedded_index(nvlist_t *nvl,
+    const char *name, nvpair_t **ret, int *ip, char **ep)
+{
+	return (nvlist_lookup_nvpair_ei_sep(nvl, name, '.', ret, ip, ep));
+}
+
+boolean_t
+nvlist_exists(nvlist_t *nvl, const char *name)
+{
+	nvpriv_t *priv;
+	nvpair_t *nvp;
+	i_nvp_t *curr;
+
+	if (name == NULL || nvl == NULL ||
+	    (priv = (nvpriv_t *)(uintptr_t)nvl->nvl_priv) == NULL)
+		return (B_FALSE);
+
+	for (curr = priv->nvp_list; curr != NULL; curr = curr->nvi_next) {
+		nvp = &curr->nvi_nvp;
+
+		if (strcmp(name, NVP_NAME(nvp)) == 0)
+			return (B_TRUE);
+	}
+
+	return (B_FALSE);
+}
+
 int
 nvpair_value_boolean_value(nvpair_t *nvp, boolean_t *val)
 {
@@ -1539,6 +1812,14 @@ nvpair_value_uint64(nvpair_t *nvp, uint64_t *val)
 	return (nvpair_value_common(nvp, DATA_TYPE_UINT64, NULL, val));
 }
 
+#if !defined(_KERNEL)
+int
+nvpair_value_double(nvpair_t *nvp, double *val)
+{
+	return (nvpair_value_common(nvp, DATA_TYPE_DOUBLE, NULL, val));
+}
+#endif
+
 int
 nvpair_value_string(nvpair_t *nvp, char **val)
 {
@@ -2676,7 +2957,11 @@ nvs_xdr_nvp_op(nvstream_t *nvs, nvpair_t *nvp)
 		 */
 		ret = xdr_longlong_t(xdr, (void *)buf);
 		break;
-
+#if !defined(_KERNEL)
+	case DATA_TYPE_DOUBLE:
+		ret = xdr_double(xdr, (void *)buf);
+		break;
+#endif
 	case DATA_TYPE_STRING:
 		ret = xdr_string(xdr, &buf, buflen - 1);
 		break;
@@ -2782,6 +3067,9 @@ nvs_xdr_nvp_size(nvstream_t *nvs, nvpair_t *nvp, size_t *size)
 	case DATA_TYPE_INT64:
 	case DATA_TYPE_UINT64:
 	case DATA_TYPE_HRTIME:
+#if !defined(_KERNEL)
+	case DATA_TYPE_DOUBLE:
+#endif
 		nvp_sz += 8;
 		break;
 
diff --git a/sys/cddl/contrib/opensolaris/common/unicode/u8_textprep.c b/sys/cddl/contrib/opensolaris/common/unicode/u8_textprep.c
new file mode 100644
index 000000000000..73cf74a4d159
--- /dev/null
+++ b/sys/cddl/contrib/opensolaris/common/unicode/u8_textprep.c
@@ -0,0 +1,2130 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License (the "License").
+ * You may not use this file except in compliance with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or http://www.opensolaris.org/os/licensing.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+/*
+ * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+ * Use is subject to license terms.
+ */
+
+#pragma ident	"%Z%%M%	%I%	%E% SMI"
+
+
+/*
+ * UTF-8 text preparation functions (PSARC/2007/149, PSARC/2007/458).
+ *
+ * Man pages: u8_textprep_open(9F), u8_textprep_buf(9F), u8_textprep_close(9F),
+ * u8_textprep_str(9F), u8_strcmp(9F), and u8_validate(9F). See also
+ * the section 3C man pages.
+ * Interface stability: Committed.
+ */
+
+#include <sys/types.h>
+#ifdef	_KERNEL
+#include <sys/param.h>
+#include <sys/sysmacros.h>
+#include <sys/systm.h>
+#include <sys/debug.h>
+#include <sys/kmem.h>
+#else
+#include <strings.h>
+#endif	/* _KERNEL */
+#include <sys/byteorder.h>
+#include <sys/errno.h>
+#include <sys/u8_textprep.h>
+#include <sys/u8_textprep_data.h>
+
+
+/* The maximum possible number of bytes in a UTF-8 character. */
+#define	U8_MB_CUR_MAX			(4)
+
+/*
+ * The maximum number of bytes needed for a UTF-8 character to cover
+ * U+0000 - U+FFFF, i.e., the coding space of now deprecated UCS-2.
+ */
+#define	U8_MAX_BYTES_UCS2		(3)
+
+/* The maximum possible number of bytes in a Stream-Safe Text. */
+#define	U8_STREAM_SAFE_TEXT_MAX		(128)
+
+/*
+ * The maximum number of characters in a combining/conjoining sequence and
+ * the actual upperbound limit of a combining/conjoining sequence.
+ */
+#define	U8_MAX_CHARS_A_SEQ		(32)
+#define	U8_UPPER_LIMIT_IN_A_SEQ		(31)
+
+/* The combining class value for Starter. */
+#define	U8_COMBINING_CLASS_STARTER	(0)
+
+/*
+ * Some Hangul related macros at below.
+ *
+ * The first and the last of Hangul syllables, Hangul Jamo Leading consonants,
+ * Vowels, and optional Trailing consonants in Unicode scalar values.
+ *
+ * Please be noted that the U8_HANGUL_JAMO_T_FIRST is 0x11A7 at below not
+ * the actual U+11A8. This is due to that the trailing consonant is optional
+ * and thus we are doing a pre-calculation of subtracting one.
+ *
+ * Each of 19 modern leading consonants has total 588 possible syllables since
+ * Hangul has 21 modern vowels and 27 modern trailing consonants plus 1 for
+ * no trailing consonant case, i.e., 21 x 28 = 588.
+ *
+ * We also have bunch of Hangul related macros at below. Please bear in mind
+ * that the U8_HANGUL_JAMO_1ST_BYTE can be used to check whether it is
+ * a Hangul Jamo or not but the value does not guarantee that it is a Hangul
+ * Jamo; it just guarantee that it will be most likely.
+ */
+#define	U8_HANGUL_SYL_FIRST		(0xAC00U)
+#define	U8_HANGUL_SYL_LAST		(0xD7A3U)
+
+#define	U8_HANGUL_JAMO_L_FIRST		(0x1100U)
+#define	U8_HANGUL_JAMO_L_LAST		(0x1112U)
+#define	U8_HANGUL_JAMO_V_FIRST		(0x1161U)
+#define	U8_HANGUL_JAMO_V_LAST		(0x1175U)
+#define	U8_HANGUL_JAMO_T_FIRST		(0x11A7U)
+#define	U8_HANGUL_JAMO_T_LAST		(0x11C2U)
+
+#define	U8_HANGUL_V_COUNT		(21)
+#define	U8_HANGUL_VT_COUNT		(588)
+#define	U8_HANGUL_T_COUNT		(28)
+
+#define	U8_HANGUL_JAMO_1ST_BYTE		(0xE1U)
+
+#define	U8_SAVE_HANGUL_AS_UTF8(s, i, j, k, b) \
+	(s)[(i)] = (uchar_t)(0xE0U | ((uint32_t)(b) & 0xF000U) >> 12); \
+	(s)[(j)] = (uchar_t)(0x80U | ((uint32_t)(b) & 0x0FC0U) >> 6); \
+	(s)[(k)] = (uchar_t)(0x80U | ((uint32_t)(b) & 0x003FU));
+
+#define	U8_HANGUL_JAMO_L(u) \
+	((u) >= U8_HANGUL_JAMO_L_FIRST && (u) <= U8_HANGUL_JAMO_L_LAST)
+
+#define	U8_HANGUL_JAMO_V(u) \
+	((u) >= U8_HANGUL_JAMO_V_FIRST && (u) <= U8_HANGUL_JAMO_V_LAST)
+
+#define	U8_HANGUL_JAMO_T(u) \
+	((u) > U8_HANGUL_JAMO_T_FIRST && (u) <= U8_HANGUL_JAMO_T_LAST)
+
+#define	U8_HANGUL_JAMO(u) \
+	((u) >= U8_HANGUL_JAMO_L_FIRST && (u) <= U8_HANGUL_JAMO_T_LAST)
+
+#define	U8_HANGUL_SYLLABLE(u) \
+	((u) >= U8_HANGUL_SYL_FIRST && (u) <= U8_HANGUL_SYL_LAST)
+
+#define	U8_HANGUL_COMPOSABLE_L_V(s, u) \
+	((s) == U8_STATE_HANGUL_L && U8_HANGUL_JAMO_V((u)))
+
+#define	U8_HANGUL_COMPOSABLE_LV_T(s, u) \
+	((s) == U8_STATE_HANGUL_LV && U8_HANGUL_JAMO_T((u)))
+
+/* The types of decomposition mappings. */
+#define	U8_DECOMP_BOTH			(0xF5U)
+#define	U8_DECOMP_CANONICAL		(0xF6U)
+
+/* The indicator for 16-bit table. */
+#define	U8_16BIT_TABLE_INDICATOR	(0x8000U)
+
+/* The following are some convenience macros. */
+#define	U8_PUT_3BYTES_INTO_UTF32(u, b1, b2, b3) \
+	(u) = ((uint32_t)(b1) & 0x0F) << 12 | ((uint32_t)(b2) & 0x3F) << 6 | \
+		(uint32_t)(b3) & 0x3F;
+
+#define	U8_SIMPLE_SWAP(a, b, t) \
+	(t) = (a); \
+	(a) = (b); \
+	(b) = (t);
+
+#define	U8_ASCII_TOUPPER(c) \
+	(((c) >= 'a' && (c) <= 'z') ? (c) - 'a' + 'A' : (c))
+
+#define	U8_ASCII_TOLOWER(c) \
+	(((c) >= 'A' && (c) <= 'Z') ? (c) - 'A' + 'a' : (c))
+
+#define	U8_ISASCII(c)			(((uchar_t)(c)) < 0x80U)
+/*
+ * The following macro assumes that the two characters that are to be
+ * swapped are adjacent to each other and 'a' comes before 'b'.
+ *
+ * If the assumptions are not met, then, the macro will fail.
+ */
+#define	U8_SWAP_COMB_MARKS(a, b) \
+	for (k = 0; k < disp[(a)]; k++) \
+		u8t[k] = u8s[start[(a)] + k]; \
+	for (k = 0; k < disp[(b)]; k++) \
+		u8s[start[(a)] + k] = u8s[start[(b)] + k]; \
+	start[(b)] = start[(a)] + disp[(b)]; \
+	for (k = 0; k < disp[(a)]; k++) \
+		u8s[start[(b)] + k] = u8t[k]; \
+	U8_SIMPLE_SWAP(comb_class[(a)], comb_class[(b)], tc); \
+	U8_SIMPLE_SWAP(disp[(a)], disp[(b)], tc);
+
+/* The possible states during normalization. */
+typedef enum {
+	U8_STATE_START = 0,
+	U8_STATE_HANGUL_L = 1,
+	U8_STATE_HANGUL_LV = 2,
+	U8_STATE_HANGUL_LVT = 3,
+	U8_STATE_HANGUL_V = 4,
+	U8_STATE_HANGUL_T = 5,
+	U8_STATE_COMBINING_MARK = 6
+} u8_normalization_states_t;
+
+/*
+ * The three vectors at below are used to check bytes of a given UTF-8
+ * character are valid and not containing any malformed byte values.
+ *
+ * We used to have a quite relaxed UTF-8 binary representation but then there
+ * was some security related issues and so the Unicode Consortium defined
+ * and announced the UTF-8 Corrigendum at Unicode 3.1 and then refined it
+ * one more time at the Unicode 3.2. The following three tables are based on
+ * that.
+ */
+
+#define	U8_ILLEGAL_NEXT_BYTE_COMMON(c)	((c) < 0x80 || (c) > 0xBF)
+
+#define	I_				U8_ILLEGAL_CHAR
+#define	O_				U8_OUT_OF_RANGE_CHAR
+
+const int8_t u8_number_of_bytes[0x100] = {
+	1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,
+	1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,
+	1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,
+	1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,
+	1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,
+	1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,
+	1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,
+	1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,
+
+/*	80  81  82  83  84  85  86  87  88  89  8A  8B  8C  8D  8E  8F  */
+	I_, I_, I_, I_, I_, I_, I_, I_, I_, I_, I_, I_, I_, I_, I_, I_,
+
+/*  	90  91  92  93  94  95  96  97  98  99  9A  9B  9C  9D  9E  9F  */
+	I_, I_, I_, I_, I_, I_, I_, I_, I_, I_, I_, I_, I_, I_, I_, I_,
+
+/*  	A0  A1  A2  A3  A4  A5  A6  A7  A8  A9  AA  AB  AC  AD  AE  AF  */
+	I_, I_, I_, I_, I_, I_, I_, I_, I_, I_, I_, I_, I_, I_, I_, I_,
+
+/*	B0  B1  B2  B3  B4  B5  B6  B7  B8  B9  BA  BB  BC  BD  BE  BF  */
+	I_, I_, I_, I_, I_, I_, I_, I_, I_, I_, I_, I_, I_, I_, I_, I_,
+
+/*	C0  C1  C2  C3  C4  C5  C6  C7  C8  C9  CA  CB  CC  CD  CE  CF  */
+	I_, I_, 2,  2,  2,  2,  2,  2,  2,  2,  2,  2,  2,  2,  2,  2,
+
+/*	D0  D1  D2  D3  D4  D5  D6  D7  D8  D9  DA  DB  DC  DD  DE  DF  */
+	2,  2,  2,  2,  2,  2,  2,  2,  2,  2,  2,  2,  2,  2,  2,  2,
+
+/*	E0  E1  E2  E3  E4  E5  E6  E7  E8  E9  EA  EB  EC  ED  EE  EF  */
+	3,  3,  3,  3,  3,  3,  3,  3,  3,  3,  3,  3,  3,  3,  3,  3,
+
+/*	F0  F1  F2  F3  F4  F5  F6  F7  F8  F9  FA  FB  FC  FD  FE  FF  */
+	4,  4,  4,  4,  4,  O_, O_, O_, O_, O_, O_, O_, O_, O_, O_, O_,
+};
+
+#undef	I_
+#undef	O_
+
+const uint8_t u8_valid_min_2nd_byte[0x100] = {
+	0,    0,    0,    0,    0,    0,    0,    0,
+	0,    0,    0,    0,    0,    0,    0,    0,
+	0,    0,    0,    0,    0,    0,    0,    0,
+	0,    0,    0,    0,    0,    0,    0,    0,
+	0,    0,    0,    0,    0,    0,    0,    0,
+	0,    0,    0,    0,    0,    0,    0,    0,
+	0,    0,    0,    0,    0,    0,    0,    0,
+	0,    0,    0,    0,    0,    0,    0,    0,
+	0,    0,    0,    0,    0,    0,    0,    0,
+	0,    0,    0,    0,    0,    0,    0,    0,
+	0,    0,    0,    0,    0,    0,    0,    0,
+	0,    0,    0,    0,    0,    0,    0,    0,
+	0,    0,    0,    0,    0,    0,    0,    0,
+	0,    0,    0,    0,    0,    0,    0,    0,
+	0,    0,    0,    0,    0,    0,    0,    0,
+	0,    0,    0,    0,    0,    0,    0,    0,
+	0,    0,    0,    0,    0,    0,    0,    0,
+	0,    0,    0,    0,    0,    0,    0,    0,
+	0,    0,    0,    0,    0,    0,    0,    0,
+	0,    0,    0,    0,    0,    0,    0,    0,
+	0,    0,    0,    0,    0,    0,    0,    0,
+	0,    0,    0,    0,    0,    0,    0,    0,
+	0,    0,    0,    0,    0,    0,    0,    0,
+	0,    0,    0,    0,    0,    0,    0,    0,
+/*	C0    C1    C2    C3    C4    C5    C6    C7    */
+	0,    0,    0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
+/*	C8    C9    CA    CB    CC    CD    CE    CF    */
+	0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
+/*	D0    D1    D2    D3    D4    D5    D6    D7    */
+	0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
+/*	D8    D9    DA    DB    DC    DD    DE    DF    */
+	0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
+/*	E0    E1    E2    E3    E4    E5    E6    E7    */
+	0xa0, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
+/*	E8    E9    EA    EB    EC    ED    EE    EF    */
+	0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
+/*	F0    F1    F2    F3    F4    F5    F6    F7    */
+	0x90, 0x80, 0x80, 0x80, 0x80, 0,    0,    0,
+	0,    0,    0,    0,    0,    0,    0,    0,
+};
+
+const uint8_t u8_valid_max_2nd_byte[0x100] = {
+	0,    0,    0,    0,    0,    0,    0,    0,
+	0,    0,    0,    0,    0,    0,    0,    0,
+	0,    0,    0,    0,    0,    0,    0,    0,
+	0,    0,    0,    0,    0,    0,    0,    0,
+	0,    0,    0,    0,    0,    0,    0,    0,
+	0,    0,    0,    0,    0,    0,    0,    0,
+	0,    0,    0,    0,    0,    0,    0,    0,
+	0,    0,    0,    0,    0,    0,    0,    0,
+	0,    0,    0,    0,    0,    0,    0,    0,
+	0,    0,    0,    0,    0,    0,    0,    0,
+	0,    0,    0,    0,    0,    0,    0,    0,
+	0,    0,    0,    0,    0,    0,    0,    0,
+	0,    0,    0,    0,    0,    0,    0,    0,
+	0,    0,    0,    0,    0,    0,    0,    0,
+	0,    0,    0,    0,    0,    0,    0,    0,
+	0,    0,    0,    0,    0,    0,    0,    0,
+	0,    0,    0,    0,    0,    0,    0,    0,
+	0,    0,    0,    0,    0,    0,    0,    0,
+	0,    0,    0,    0,    0,    0,    0,    0,
+	0,    0,    0,    0,    0,    0,    0,    0,
+	0,    0,    0,    0,    0,    0,    0,    0,
+	0,    0,    0,    0,    0,    0,    0,    0,
+	0,    0,    0,    0,    0,    0,    0,    0,
+	0,    0,    0,    0,    0,    0,    0,    0,
+/*	C0    C1    C2    C3    C4    C5    C6    C7    */
+	0,    0,    0xbf, 0xbf, 0xbf, 0xbf, 0xbf, 0xbf,
+/*	C8    C9    CA    CB    CC    CD    CE    CF    */
+	0xbf, 0xbf, 0xbf, 0xbf, 0xbf, 0xbf, 0xbf, 0xbf,
+/*	D0    D1    D2    D3    D4    D5    D6    D7    */
+	0xbf, 0xbf, 0xbf, 0xbf, 0xbf, 0xbf, 0xbf, 0xbf,
+/*	D8    D9    DA    DB    DC    DD    DE    DF    */
+	0xbf, 0xbf, 0xbf, 0xbf, 0xbf, 0xbf, 0xbf, 0xbf,
+/*	E0    E1    E2    E3    E4    E5    E6    E7    */
+	0xbf, 0xbf, 0xbf, 0xbf, 0xbf, 0xbf, 0xbf, 0xbf,
+/*	E8    E9    EA    EB    EC    ED    EE    EF    */
+	0xbf, 0xbf, 0xbf, 0xbf, 0xbf, 0x9f, 0xbf, 0xbf,
+/*	F0    F1    F2    F3    F4    F5    F6    F7    */
+	0xbf, 0xbf, 0xbf, 0xbf, 0x8f, 0,    0,    0,
+	0,    0,    0,    0,    0,    0,    0,    0,
+};
+
+
+/*
+ * The u8_validate() validates on the given UTF-8 character string and
+ * calculate the byte length. It is quite similar to mblen(3C) except that
+ * this will validate against the list of characters if required and
+ * specific to UTF-8 and Unicode.
+ */
+int
+u8_validate(char *u8str, size_t n, char **list, int flag, int *errnum)
+{
+	uchar_t *ib;
+	uchar_t *ibtail;
+	uchar_t **p;
+	uchar_t *s1;
+	uchar_t *s2;
+	uchar_t f;
+	int sz;
+	size_t i;
+	int ret_val;
+	boolean_t second;
+	boolean_t no_need_to_validate_entire;
+	boolean_t check_additional;
+	boolean_t validate_ucs2_range_only;
+
+	if (! u8str)
+		return (0);
+
+	ib = (uchar_t *)u8str;
+	ibtail = ib + n;
+
+	ret_val = 0;
+
+	no_need_to_validate_entire = ! (flag & U8_VALIDATE_ENTIRE);
+	check_additional = flag & U8_VALIDATE_CHECK_ADDITIONAL;
+	validate_ucs2_range_only = flag & U8_VALIDATE_UCS2_RANGE;
+
+	while (ib < ibtail) {
+		/*
+		 * The first byte of a UTF-8 character tells how many
+		 * bytes will follow for the character. If the first byte
+		 * is an illegal byte value or out of range value, we just
+		 * return -1 with an appropriate error number.
+		 */
+		sz = u8_number_of_bytes[*ib];
+		if (sz == U8_ILLEGAL_CHAR) {
+			*errnum = EILSEQ;
+			return (-1);
+		}
+
+		if (sz == U8_OUT_OF_RANGE_CHAR ||
+		    (validate_ucs2_range_only && sz > U8_MAX_BYTES_UCS2)) {
+			*errnum = ERANGE;
+			return (-1);
+		}
+
+		/*
+		 * If we don't have enough bytes to check on, that's also
+		 * an error. As you can see, we give illegal byte sequence
+		 * checking higher priority then EINVAL cases.
+		 */
+		if ((ibtail - ib) < sz) {
+			*errnum = EINVAL;
+			return (-1);
+		}
+
+		if (sz == 1) {
+			ib++;
+			ret_val++;
+		} else {
+			/*
+			 * Check on the multi-byte UTF-8 character. For more
+			 * details on this, see comment added for the used
+			 * data structures at the beginning of the file.
+			 */
+			f = *ib++;
+			ret_val++;
+			second = B_TRUE;
+			for (i = 1; i < sz; i++) {
+				if (second) {
+					if (*ib < u8_valid_min_2nd_byte[f] ||
+					    *ib > u8_valid_max_2nd_byte[f]) {
+						*errnum = EILSEQ;
+						return (-1);
+					}
+					second = B_FALSE;
+				} else if (U8_ILLEGAL_NEXT_BYTE_COMMON(*ib)) {
+					*errnum = EILSEQ;
+					return (-1);
+				}
+				ib++;
+				ret_val++;
+			}
+		}
+
+		if (check_additional) {
+			for (p = (uchar_t **)list, i = 0; p[i]; i++) {
+				s1 = ib - sz;
+				s2 = p[i];
+				while (s1 < ib) {
+					if (*s1 != *s2 || *s2 == '\0')
+						break;
+					s1++;
+					s2++;
+				}
+
+				if (s1 >= ib && *s2 == '\0') {
+					*errnum = EBADF;
+					return (-1);
+				}
+			}
+		}
+
+		if (no_need_to_validate_entire)
+			break;
+	}
+
+	return (ret_val);
+}
+
+/*
+ * The do_case_conv() looks at the mapping tables and returns found
+ * bytes if any. If not found, the input bytes are returned. The function
+ * always terminate the return bytes with a null character assuming that
+ * there are plenty of room to do so.
+ *
+ * The case conversions are simple case conversions mapping a character to
+ * another character as specified in the Unicode data. The byte size of
+ * the mapped character could be different from that of the input character.
+ *
+ * The return value is the byte length of the returned character excluding
+ * the terminating null byte.
+ */
+static size_t
+do_case_conv(int uv, uchar_t *u8s, uchar_t *s, int sz, boolean_t is_it_toupper)
+{
+	size_t i;
+	uint16_t b1 = 0;
+	uint16_t b2 = 0;
+	uint16_t b3 = 0;
+	uint16_t b3_tbl;
+	uint16_t b3_base;
+	uint16_t b4 = 0;
+	size_t start_id;
+	size_t end_id;
+
+	/*
+	 * At this point, the only possible values for sz are 2, 3, and 4.
+	 * The u8s should point to a vector that is well beyond the size of
+	 * 5 bytes.
+	 */
+	if (sz == 2) {
+		b3 = u8s[0] = s[0];
+		b4 = u8s[1] = s[1];
+	} else if (sz == 3) {
+		b2 = u8s[0] = s[0];
+		b3 = u8s[1] = s[1];
+		b4 = u8s[2] = s[2];
+	} else if (sz == 4) {
+		b1 = u8s[0] = s[0];
+		b2 = u8s[1] = s[1];
+		b3 = u8s[2] = s[2];
+		b4 = u8s[3] = s[3];
+	} else {
+		/* This is not possible but just in case as a fallback. */
+		if (is_it_toupper)
+			*u8s = U8_ASCII_TOUPPER(*s);
+		else
+			*u8s = U8_ASCII_TOLOWER(*s);
+		u8s[1] = '\0';
+
+		return (1);
+	}
+	u8s[sz] = '\0';
+
+	/*
+	 * Let's find out if we have a corresponding character.
+	 */
+	b1 = u8_common_b1_tbl[uv][b1];
+	if (b1 == U8_TBL_ELEMENT_NOT_DEF)
+		return ((size_t)sz);
+
+	b2 = u8_case_common_b2_tbl[uv][b1][b2];
+	if (b2 == U8_TBL_ELEMENT_NOT_DEF)
+		return ((size_t)sz);
+
+	if (is_it_toupper) {
+		b3_tbl = u8_toupper_b3_tbl[uv][b2][b3].tbl_id;
+		if (b3_tbl == U8_TBL_ELEMENT_NOT_DEF)
+			return ((size_t)sz);
+
+		start_id = u8_toupper_b4_tbl[uv][b3_tbl][b4];
+		end_id = u8_toupper_b4_tbl[uv][b3_tbl][b4 + 1];
+
+		/* Either there is no match or an error at the table. */
+		if (start_id >= end_id || (end_id - start_id) > U8_MB_CUR_MAX)
+			return ((size_t)sz);
+
+		b3_base = u8_toupper_b3_tbl[uv][b2][b3].base;
+
+		for (i = 0; start_id < end_id; start_id++)
+			u8s[i++] = u8_toupper_final_tbl[uv][b3_base + start_id];
+	} else {
+		b3_tbl = u8_tolower_b3_tbl[uv][b2][b3].tbl_id;
+		if (b3_tbl == U8_TBL_ELEMENT_NOT_DEF)
+			return ((size_t)sz);
+
+		start_id = u8_tolower_b4_tbl[uv][b3_tbl][b4];
+		end_id = u8_tolower_b4_tbl[uv][b3_tbl][b4 + 1];
+
+		if (start_id >= end_id || (end_id - start_id) > U8_MB_CUR_MAX)
+			return ((size_t)sz);
+
+		b3_base = u8_tolower_b3_tbl[uv][b2][b3].base;
+
+		for (i = 0; start_id < end_id; start_id++)
+			u8s[i++] = u8_tolower_final_tbl[uv][b3_base + start_id];
+	}
+
+	/*
+	 * If i is still zero, that means there is no corresponding character.
+	 */
+	if (i == 0)
+		return ((size_t)sz);
+
+	u8s[i] = '\0';
+
+	return (i);
+}
+
+/*
+ * The do_case_compare() function compares the two input strings, s1 and s2,
+ * one character at a time doing case conversions if applicable and return
+ * the comparison result as like strcmp().
+ *
+ * Since, in empirical sense, most of text data are 7-bit ASCII characters,
+ * we treat the 7-bit ASCII characters as a special case trying to yield
+ * faster processing time.
+ */
+static int
+do_case_compare(size_t uv, uchar_t *s1, uchar_t *s2, size_t n1,
+	size_t n2, boolean_t is_it_toupper, int *errnum)
+{
+	int f;
+	int sz1;
+	int sz2;
+	size_t j;
+	size_t i1;
+	size_t i2;
+	uchar_t u8s1[U8_MB_CUR_MAX + 1];
+	uchar_t u8s2[U8_MB_CUR_MAX + 1];
+
+	i1 = i2 = 0;
+	while (i1 < n1 && i2 < n2) {
+		/*
+		 * Find out what would be the byte length for this UTF-8
+		 * character at string s1 and also find out if this is
+		 * an illegal start byte or not and if so, issue a proper
+		 * error number and yet treat this byte as a character.
+		 */
+		sz1 = u8_number_of_bytes[*s1];
+		if (sz1 < 0) {
+			*errnum = EILSEQ;
+			sz1 = 1;
+		}
+
+		/*
+		 * For 7-bit ASCII characters mainly, we do a quick case
+		 * conversion right at here.
+		 *
+		 * If we don't have enough bytes for this character, issue
+		 * an EINVAL error and use what are available.
+		 *
+		 * If we have enough bytes, find out if there is
+		 * a corresponding uppercase character and if so, copy over
+		 * the bytes for a comparison later. If there is no
+		 * corresponding uppercase character, then, use what we have
+		 * for the comparison.
+		 */
+		if (sz1 == 1) {
+			if (is_it_toupper)
+				u8s1[0] = U8_ASCII_TOUPPER(*s1);
+			else
+				u8s1[0] = U8_ASCII_TOLOWER(*s1);
+			s1++;
+			u8s1[1] = '\0';
+		} else if ((i1 + sz1) > n1) {
+			*errnum = EINVAL;
+			for (j = 0; (i1 + j) < n1; )
+				u8s1[j++] = *s1++;
+			u8s1[j] = '\0';
+		} else {
+			(void) do_case_conv(uv, u8s1, s1, sz1, is_it_toupper);
+			s1 += sz1;
+		}
+
+		/* Do the same for the string s2. */
+		sz2 = u8_number_of_bytes[*s2];
+		if (sz2 < 0) {
+			*errnum = EILSEQ;
+			sz2 = 1;
+		}
+
+		if (sz2 == 1) {
+			if (is_it_toupper)
+				u8s2[0] = U8_ASCII_TOUPPER(*s2);
+			else
+				u8s2[0] = U8_ASCII_TOLOWER(*s2);
+			s2++;
+			u8s2[1] = '\0';
+		} else if ((i2 + sz2) > n2) {
+			*errnum = EINVAL;
+			for (j = 0; (i2 + j) < n2; )
+				u8s2[j++] = *s2++;
+			u8s2[j] = '\0';
+		} else {
+			(void) do_case_conv(uv, u8s2, s2, sz2, is_it_toupper);
+			s2 += sz2;
+		}
+
+		/* Now compare the two characters. */
+		if (sz1 == 1 && sz2 == 1) {
+			if (*u8s1 > *u8s2)
+				return (1);
+			if (*u8s1 < *u8s2)
+				return (-1);
+		} else {
+			f = strcmp((const char *)u8s1, (const char *)u8s2);
+			if (f != 0)
+				return (f);
+		}
+
+		/*
+		 * They were the same. Let's move on to the next
+		 * characters then.
+		 */
+		i1 += sz1;
+		i2 += sz2;
+	}
+
+	/*
+	 * We compared until the end of either or both strings.
+	 *
+	 * If we reached to or went over the ends for the both, that means
+	 * they are the same.
+	 *
+	 * If we reached only one of the two ends, that means the other string
+	 * has something which then the fact can be used to determine
+	 * the return value.
+	 */
+	if (i1 >= n1) {
+		if (i2 >= n2)
+			return (0);
+		return (-1);
+	}
+	return (1);
+}
+
+/*
+ * The combining_class() function checks on the given bytes and find out
+ * the corresponding Unicode combining class value. The return value 0 means
+ * it is a Starter. Any illegal UTF-8 character will also be treated as
+ * a Starter.
+ */
+static uchar_t
+combining_class(size_t uv, uchar_t *s, size_t sz)
+{
+	uint16_t b1 = 0;
+	uint16_t b2 = 0;
+	uint16_t b3 = 0;
+	uint16_t b4 = 0;
+
+	if (sz == 1 || sz > 4)
+		return (0);
+
+	if (sz == 2) {
+		b3 = s[0];
+		b4 = s[1];
+	} else if (sz == 3) {
+		b2 = s[0];
+		b3 = s[1];
+		b4 = s[2];
+	} else if (sz == 4) {
+		b1 = s[0];
+		b2 = s[1];
+		b3 = s[2];
+		b4 = s[3];
+	}
+
+	b1 = u8_common_b1_tbl[uv][b1];
+	if (b1 == U8_TBL_ELEMENT_NOT_DEF)
+		return (0);
+
+	b2 = u8_combining_class_b2_tbl[uv][b1][b2];
+	if (b2 == U8_TBL_ELEMENT_NOT_DEF)
+		return (0);
+
+	b3 = u8_combining_class_b3_tbl[uv][b2][b3];
+	if (b3 == U8_TBL_ELEMENT_NOT_DEF)
+		return (0);
+
+	return (u8_combining_class_b4_tbl[uv][b3][b4]);
+}
+
+/*
+ * The do_decomp() function finds out a matching decomposition if any
+ * and return. If there is no match, the input bytes are copied and returned.
+ * The function also checks if there is a Hangul, decomposes it if necessary
+ * and returns.
+ *
+ * To save time, a single byte 7-bit ASCII character should be handled by
+ * the caller.
+ *
+ * The function returns the number of bytes returned sans always terminating
+ * the null byte. It will also return a state that will tell if there was
+ * a Hangul character decomposed which then will be used by the caller.
+ */
+static size_t
+do_decomp(size_t uv, uchar_t *u8s, uchar_t *s, int sz,
+	boolean_t canonical_decomposition, u8_normalization_states_t *state)
+{
+	uint16_t b1 = 0;
+	uint16_t b2 = 0;
+	uint16_t b3 = 0;
+	uint16_t b3_tbl;
+	uint16_t b3_base;
+	uint16_t b4 = 0;
+	size_t start_id;
+	size_t end_id;
+	size_t i;
+	uint32_t u1;
+
+	if (sz == 2) {
+		b3 = u8s[0] = s[0];
+		b4 = u8s[1] = s[1];
+		u8s[2] = '\0';
+	} else if (sz == 3) {
+		/* Convert it to a Unicode scalar value. */
+		U8_PUT_3BYTES_INTO_UTF32(u1, s[0], s[1], s[2]);
+
+		/*
+		 * If this is a Hangul syllable, we decompose it into
+		 * a leading consonant, a vowel, and an optional trailing
+		 * consonant and then return.
+		 */
+		if (U8_HANGUL_SYLLABLE(u1)) {
+			u1 -= U8_HANGUL_SYL_FIRST;
+
+			b1 = U8_HANGUL_JAMO_L_FIRST + u1 / U8_HANGUL_VT_COUNT;
+			b2 = U8_HANGUL_JAMO_V_FIRST + (u1 % U8_HANGUL_VT_COUNT)
+			    / U8_HANGUL_T_COUNT;
+			b3 = u1 % U8_HANGUL_T_COUNT;
+
+			U8_SAVE_HANGUL_AS_UTF8(u8s, 0, 1, 2, b1);
+			U8_SAVE_HANGUL_AS_UTF8(u8s, 3, 4, 5, b2);
+			if (b3) {
+				b3 += U8_HANGUL_JAMO_T_FIRST;
+				U8_SAVE_HANGUL_AS_UTF8(u8s, 6, 7, 8, b3);
+
+				u8s[9] = '\0';
+				*state = U8_STATE_HANGUL_LVT;
+				return (9);
+			}
+
+			u8s[6] = '\0';
+			*state = U8_STATE_HANGUL_LV;
+			return (6);
+		}
+
+		b2 = u8s[0] = s[0];
+		b3 = u8s[1] = s[1];
+		b4 = u8s[2] = s[2];
+		u8s[3] = '\0';
+
+		/*
+		 * If this is a Hangul Jamo, we know there is nothing
+		 * further that we can decompose.
+		 */
+		if (U8_HANGUL_JAMO_L(u1)) {
+			*state = U8_STATE_HANGUL_L;
+			return (3);
+		}
+
+		if (U8_HANGUL_JAMO_V(u1)) {
+			if (*state == U8_STATE_HANGUL_L)
+				*state = U8_STATE_HANGUL_LV;
+			else
+				*state = U8_STATE_HANGUL_V;
+			return (3);
+		}
+
+		if (U8_HANGUL_JAMO_T(u1)) {
+			if (*state == U8_STATE_HANGUL_LV)
+				*state = U8_STATE_HANGUL_LVT;
+			else
+				*state = U8_STATE_HANGUL_T;
+			return (3);
+		}
+	} else if (sz == 4) {
+		b1 = u8s[0] = s[0];
+		b2 = u8s[1] = s[1];
+		b3 = u8s[2] = s[2];
+		b4 = u8s[3] = s[3];
+		u8s[4] = '\0';
+	} else {
+		/*
+		 * This is a fallback and should not happen if the function
+		 * was called properly.
+		 */
+		u8s[0] = s[0];
+		u8s[1] = '\0';
+		*state = U8_STATE_START;
+		return (1);
+	}
+
+	/*
+	 * At this point, this rountine does not know what it would get.
+	 * The caller should sort it out if the state isn't a Hangul one.
+	 */
+	*state = U8_STATE_START;
+
+	/* Try to find matching decomposition mapping byte sequence. */
+	b1 = u8_common_b1_tbl[uv][b1];
+	if (b1 == U8_TBL_ELEMENT_NOT_DEF)
+		return ((size_t)sz);
+
+	b2 = u8_decomp_b2_tbl[uv][b1][b2];
+	if (b2 == U8_TBL_ELEMENT_NOT_DEF)
+		return ((size_t)sz);
+
+	b3_tbl = u8_decomp_b3_tbl[uv][b2][b3].tbl_id;
+	if (b3_tbl == U8_TBL_ELEMENT_NOT_DEF)
+		return ((size_t)sz);
+
+	/*
+	 * If b3_tbl is bigger than or equal to U8_16BIT_TABLE_INDICATOR
+	 * which is 0x8000, this means we couldn't fit the mappings into
+	 * the cardinality of a unsigned byte.
+	 */
+	if (b3_tbl >= U8_16BIT_TABLE_INDICATOR) {
+		b3_tbl -= U8_16BIT_TABLE_INDICATOR;
+		start_id = u8_decomp_b4_16bit_tbl[uv][b3_tbl][b4];
+		end_id = u8_decomp_b4_16bit_tbl[uv][b3_tbl][b4 + 1];
+	} else {
+		start_id = u8_decomp_b4_tbl[uv][b3_tbl][b4];
+		end_id = u8_decomp_b4_tbl[uv][b3_tbl][b4 + 1];
+	}
+
+	/* This also means there wasn't any matching decomposition. */
+	if (start_id >= end_id)
+		return ((size_t)sz);
+
+	/*
+	 * The final table for decomposition mappings has three types of
+	 * byte sequences depending on whether a mapping is for compatibility
+	 * decomposition, canonical decomposition, or both like the following:
+	 *
+	 * (1) Compatibility decomposition mappings:
+	 *
+	 *	+---+---+-...-+---+
+	 *	| B0| B1| ... | Bm|
+	 *	+---+---+-...-+---+
+	 *
+	 *	The first byte, B0, is always less then 0xF5 (U8_DECOMP_BOTH).
+	 *
+	 * (2) Canonical decomposition mappings:
+	 *
+	 *	+---+---+---+-...-+---+
+	 *	| T | b0| b1| ... | bn|
+	 *	+---+---+---+-...-+---+
+	 *
+	 *	where the first byte, T, is 0xF6 (U8_DECOMP_CANONICAL).
+	 *
+	 * (3) Both mappings:
+	 *
+	 *	+---+---+---+---+-...-+---+---+---+-...-+---+
+	 *	| T | D | b0| b1| ... | bn| B0| B1| ... | Bm|
+	 *	+---+---+---+---+-...-+---+---+---+-...-+---+
+	 *
+	 *	where T is 0xF5 (U8_DECOMP_BOTH) and D is a displacement
+	 *	byte, b0 to bn are canonical mapping bytes and B0 to Bm are
+	 *	compatibility mapping bytes.
+	 *
+	 * Note that compatibility decomposition means doing recursive
+	 * decompositions using both compatibility decomposition mappings and
+	 * canonical decomposition mappings. On the other hand, canonical
+	 * decomposition means doing recursive decompositions using only
+	 * canonical decomposition mappings. Since the table we have has gone
+	 * through the recursions already, we do not need to do so during
+	 * runtime, i.e., the table has been completely flattened out
+	 * already.
+	 */
+
+	b3_base = u8_decomp_b3_tbl[uv][b2][b3].base;
+
+	/* Get the type, T, of the byte sequence. */
+	b1 = u8_decomp_final_tbl[uv][b3_base + start_id];
+
+	/*
+	 * If necessary, adjust start_id, end_id, or both. Note that if
+	 * this is compatibility decomposition mapping, there is no
+	 * adjustment.
+	 */
+	if (canonical_decomposition) {
+		/* Is the mapping only for compatibility decomposition? */
+		if (b1 < U8_DECOMP_BOTH)
+			return ((size_t)sz);
+
+		start_id++;
+
+		if (b1 == U8_DECOMP_BOTH) {
+			end_id = start_id +
+			    u8_decomp_final_tbl[uv][b3_base + start_id];
+			start_id++;
+		}
+	} else {
+		/*
+		 * Unless this is a compatibility decomposition mapping,
+		 * we adjust the start_id.
+		 */
+		if (b1 == U8_DECOMP_BOTH) {
+			start_id++;
+			start_id += u8_decomp_final_tbl[uv][b3_base + start_id];
+		} else if (b1 == U8_DECOMP_CANONICAL) {
+			start_id++;
+		}
+	}
+
+	for (i = 0; start_id < end_id; start_id++)
+		u8s[i++] = u8_decomp_final_tbl[uv][b3_base + start_id];
+	u8s[i] = '\0';
+
+	return (i);
+}
+
+/*
+ * The find_composition_start() function uses the character bytes given and
+ * find out the matching composition mappings if any and return the address
+ * to the composition mappings as explained in the do_composition().
+ */
+static uchar_t *
+find_composition_start(size_t uv, uchar_t *s, size_t sz)
+{
+	uint16_t b1 = 0;
+	uint16_t b2 = 0;
+	uint16_t b3 = 0;
+	uint16_t b3_tbl;
+	uint16_t b3_base;
+	uint16_t b4 = 0;
+	size_t start_id;
+	size_t end_id;
+
+	if (sz == 1) {
+		b4 = s[0];
+	} else if (sz == 2) {
+		b3 = s[0];
+		b4 = s[1];
+	} else if (sz == 3) {
+		b2 = s[0];
+		b3 = s[1];
+		b4 = s[2];
+	} else if (sz == 4) {
+		b1 = s[0];
+		b2 = s[1];
+		b3 = s[2];
+		b4 = s[3];
+	} else {
+		/*
+		 * This is a fallback and should not happen if the function
+		 * was called properly.
+		 */
+		return (NULL);
+	}
+
+	b1 = u8_composition_b1_tbl[uv][b1];
+	if (b1 == U8_TBL_ELEMENT_NOT_DEF)
+		return (NULL);
+
+	b2 = u8_composition_b2_tbl[uv][b1][b2];
+	if (b2 == U8_TBL_ELEMENT_NOT_DEF)
+		return (NULL);
+
+	b3_tbl = u8_composition_b3_tbl[uv][b2][b3].tbl_id;
+	if (b3_tbl == U8_TBL_ELEMENT_NOT_DEF)
+		return (NULL);
+
+	if (b3_tbl >= U8_16BIT_TABLE_INDICATOR) {
+		b3_tbl -= U8_16BIT_TABLE_INDICATOR;
+		start_id = u8_composition_b4_16bit_tbl[uv][b3_tbl][b4];
+		end_id = u8_composition_b4_16bit_tbl[uv][b3_tbl][b4 + 1];
+	} else {
+		start_id = u8_composition_b4_tbl[uv][b3_tbl][b4];
+		end_id = u8_composition_b4_tbl[uv][b3_tbl][b4 + 1];
+	}
+
+	if (start_id >= end_id)
+		return (NULL);
+
+	b3_base = u8_composition_b3_tbl[uv][b2][b3].base;
+
+	return ((uchar_t *)&(u8_composition_final_tbl[uv][b3_base + start_id]));
+}
+
+/*
+ * The blocked() function checks on the combining class values of previous
+ * characters in this sequence and return whether it is blocked or not.
+ */
+static boolean_t
+blocked(uchar_t *comb_class, size_t last)
+{
+	uchar_t my_comb_class;
+	size_t i;
+
+	my_comb_class = comb_class[last];
+	for (i = 1; i < last; i++)
+		if (comb_class[i] >= my_comb_class ||
+		    comb_class[i] == U8_COMBINING_CLASS_STARTER)
+			return (B_TRUE);
+
+	return (B_FALSE);
+}
+
+/*
+ * The do_composition() reads the character string pointed by 's' and
+ * do necessary canonical composition and then copy over the result back to
+ * the 's'.
+ *
+ * The input argument 's' cannot contain more than 32 characters.
+ */
+static size_t
+do_composition(size_t uv, uchar_t *s, uchar_t *comb_class, uchar_t *start,
+	uchar_t *disp, size_t last, uchar_t **os, uchar_t *oslast)
+{
+	uchar_t t[U8_STREAM_SAFE_TEXT_MAX + 1];
+	uchar_t tc[U8_MB_CUR_MAX];
+	uint8_t saved_marks[U8_MAX_CHARS_A_SEQ];
+	size_t saved_marks_count;
+	uchar_t *p;
+	uchar_t *saved_p;
+	uchar_t *q;
+	size_t i;
+	size_t saved_i;
+	size_t j;
+	size_t k;
+	size_t l;
+	size_t C;
+	size_t saved_l;
+	size_t size;
+	uint32_t u1;
+	uint32_t u2;
+	boolean_t match_not_found = B_TRUE;
+
+	/*
+	 * This should never happen unless the callers are doing some strange
+	 * and unexpected things.
+	 *
+	 * The "last" is the index pointing to the last character not last + 1.
+	 */
+	if (last >= U8_MAX_CHARS_A_SEQ)
+		last = U8_UPPER_LIMIT_IN_A_SEQ;
+
+	for (i = l = 0; i <= last; i++) {
+		/*
+		 * The last or any non-Starters at the beginning, we don't
+		 * have any chance to do composition and so we just copy them
+		 * to the temporary buffer.
+		 */
+		if (i >= last || comb_class[i] != U8_COMBINING_CLASS_STARTER) {
+SAVE_THE_CHAR:
+			p = s + start[i];
+			size = disp[i];
+			for (k = 0; k < size; k++)
+				t[l++] = *p++;
+			continue;
+		}
+
+		/*
+		 * If this could be a start of Hangul Jamos, then, we try to
+		 * conjoin them.
+		 */
+		if (s[start[i]] == U8_HANGUL_JAMO_1ST_BYTE) {
+			U8_PUT_3BYTES_INTO_UTF32(u1, s[start[i]],
+			    s[start[i] + 1], s[start[i] + 2]);
+			U8_PUT_3BYTES_INTO_UTF32(u2, s[start[i] + 3],
+			    s[start[i] + 4], s[start[i] + 5]);
+
+			if (U8_HANGUL_JAMO_L(u1) && U8_HANGUL_JAMO_V(u2)) {
+				u1 -= U8_HANGUL_JAMO_L_FIRST;
+				u2 -= U8_HANGUL_JAMO_V_FIRST;
+				u1 = U8_HANGUL_SYL_FIRST +
+				    (u1 * U8_HANGUL_V_COUNT + u2) *
+				    U8_HANGUL_T_COUNT;
+
+				i += 2;
+				if (i <= last) {
+					U8_PUT_3BYTES_INTO_UTF32(u2,
+					    s[start[i]], s[start[i] + 1],
+					    s[start[i] + 2]);
+
+					if (U8_HANGUL_JAMO_T(u2)) {
+						u1 += u2 -
+						    U8_HANGUL_JAMO_T_FIRST;
+						i++;
+					}
+				}
+
+				U8_SAVE_HANGUL_AS_UTF8(t + l, 0, 1, 2, u1);
+				i--;
+				l += 3;
+				continue;
+			}
+		}
+
+		/*
+		 * Let's then find out if this Starter has composition
+		 * mapping.
+		 */
+		p = find_composition_start(uv, s + start[i], disp[i]);
+		if (p == NULL)
+			goto SAVE_THE_CHAR;
+
+		/*
+		 * We have a Starter with composition mapping and the next
+		 * character is a non-Starter. Let's try to find out if
+		 * we can do composition.
+		 */
+
+		saved_p = p;
+		saved_i = i;
+		saved_l = l;
+		saved_marks_count = 0;
+
+TRY_THE_NEXT_MARK:
+		q = s + start[++i];
+		size = disp[i];
+
+		/*
+		 * The next for() loop compares the non-Starter pointed by
+		 * 'q' with the possible (joinable) characters pointed by 'p'.
+		 *
+		 * The composition final table entry pointed by the 'p'
+		 * looks like the following:
+		 *
+		 * +---+---+---+-...-+---+---+---+---+-...-+---+---+
+		 * | C | b0| b2| ... | bn| F | B0| B1| ... | Bm| F |
+		 * +---+---+---+-...-+---+---+---+---+-...-+---+---+
+		 *
+		 * where C is the count byte indicating the number of
+		 * mapping pairs where each pair would be look like
+		 * (b0-bn F, B0-Bm F). The b0-bn are the bytes of the second
+		 * character of a canonical decomposition and the B0-Bm are
+		 * the bytes of a matching composite character. The F is
+		 * a filler byte after each character as the separator.
+		 */
+
+		match_not_found = B_TRUE;
+
+		for (C = *p++; C > 0; C--) {
+			for (k = 0; k < size; p++, k++)
+				if (*p != q[k])
+					break;
+
+			/* Have we found it? */
+			if (k >= size && *p == U8_TBL_ELEMENT_FILLER) {
+				match_not_found = B_FALSE;
+
+				l = saved_l;
+
+				while (*++p != U8_TBL_ELEMENT_FILLER)
+					t[l++] = *p;
+
+				break;
+			}
+
+			/* We didn't find; skip to the next pair. */
+			if (*p != U8_TBL_ELEMENT_FILLER)
+				while (*++p != U8_TBL_ELEMENT_FILLER)
+					;
+			while (*++p != U8_TBL_ELEMENT_FILLER)
+				;
+			p++;
+		}
+
+		/*
+		 * If there was no match, we will need to save the combining
+		 * mark for later appending. After that, if the next one
+		 * is a non-Starter and not blocked, then, we try once
+		 * again to do composition with the next non-Starter.
+		 *
+		 * If there was no match and this was a Starter, then,
+		 * this is a new start.
+		 *
+		 * If there was a match and a composition done and we have
+		 * more to check on, then, we retrieve a new composition final
+		 * table entry for the composite and then try to do the
+		 * composition again.
+		 */
+
+		if (match_not_found) {
+			if (comb_class[i] == U8_COMBINING_CLASS_STARTER) {
+				i--;
+				goto SAVE_THE_CHAR;
+			}
+
+			saved_marks[saved_marks_count++] = i;
+		}
+
+		if (saved_l == l) {
+			while (i < last) {
+				if (blocked(comb_class, i + 1))
+					saved_marks[saved_marks_count++] = ++i;
+				else
+					break;
+			}
+			if (i < last) {
+				p = saved_p;
+				goto TRY_THE_NEXT_MARK;
+			}
+		} else if (i < last) {
+			p = find_composition_start(uv, t + saved_l,
+			    l - saved_l);
+			if (p != NULL) {
+				saved_p = p;
+				goto TRY_THE_NEXT_MARK;
+			}
+		}
+
+		/*
+		 * There is no more composition possible.
+		 *
+		 * If there was no composition what so ever then we copy
+		 * over the original Starter and then append any non-Starters
+		 * remaining at the target string sequentially after that.
+		 */
+
+		if (saved_l == l) {
+			p = s + start[saved_i];
+			size = disp[saved_i];
+			for (j = 0; j < size; j++)
+				t[l++] = *p++;
+		}
+
+		for (k = 0; k < saved_marks_count; k++) {
+			p = s + start[saved_marks[k]];
+			size = disp[saved_marks[k]];
+			for (j = 0; j < size; j++)
+				t[l++] = *p++;
+		}
+	}
+
+	/*
+	 * If the last character is a Starter and if we have a character
+	 * (possibly another Starter) that can be turned into a composite,
+	 * we do so and we do so until there is no more of composition
+	 * possible.
+	 */
+	if (comb_class[last] == U8_COMBINING_CLASS_STARTER) {
+		p = *os;
+		saved_l = l - disp[last];
+
+		while (p < oslast) {
+			size = u8_number_of_bytes[*p];
+			if (size <= 1 || (p + size) > oslast)
+				break;
+
+			saved_p = p;
+
+			for (i = 0; i < size; i++)
+				tc[i] = *p++;
+
+			q = find_composition_start(uv, t + saved_l,
+			    l - saved_l);
+			if (q == NULL) {
+				p = saved_p;
+				break;
+			}
+
+			match_not_found = B_TRUE;
+
+			for (C = *q++; C > 0; C--) {
+				for (k = 0; k < size; q++, k++)
+					if (*q != tc[k])
+						break;
+
+				if (k >= size && *q == U8_TBL_ELEMENT_FILLER) {
+					match_not_found = B_FALSE;
+
+					l = saved_l;
+
+					while (*++q != U8_TBL_ELEMENT_FILLER) {
+						/*
+						 * This is practically
+						 * impossible but we don't
+						 * want to take any chances.
+						 */
+						if (l >=
+						    U8_STREAM_SAFE_TEXT_MAX) {
+							p = saved_p;
+							goto SAFE_RETURN;
+						}
+						t[l++] = *q;
+					}
+
+					break;
+				}
+
+				if (*q != U8_TBL_ELEMENT_FILLER)
+					while (*++q != U8_TBL_ELEMENT_FILLER)
+						;
+				while (*++q != U8_TBL_ELEMENT_FILLER)
+					;
+				q++;
+			}
+
+			if (match_not_found) {
+				p = saved_p;
+				break;
+			}
+		}
+SAFE_RETURN:
+		*os = p;
+	}
+
+	/*
+	 * Now we copy over the temporary string to the target string.
+	 * Since composition always reduces the number of characters or
+	 * the number of characters stay, we don't need to worry about
+	 * the buffer overflow here.
+	 */
+	for (i = 0; i < l; i++)
+		s[i] = t[i];
+	s[l] = '\0';
+
+	return (l);
+}
+
+/*
+ * The collect_a_seq() function checks on the given string s, collect
+ * a sequence of characters at u8s, and return the sequence. While it collects
+ * a sequence, it also applies case conversion, canonical or compatibility
+ * decomposition, canonical decomposition, or some or all of them and
+ * in that order.
+ *
+ * The collected sequence cannot be bigger than 32 characters since if
+ * it is having more than 31 characters, the sequence will be terminated
+ * with a U+034F COMBINING GRAPHEME JOINER (CGJ) character and turned into
+ * a Stream-Safe Text. The collected sequence is always terminated with
+ * a null byte and the return value is the byte length of the sequence
+ * including 0. The return value does not include the terminating
+ * null byte.
+ */
+static size_t
+collect_a_seq(size_t uv, uchar_t *u8s, uchar_t **source, uchar_t *slast,
+	boolean_t is_it_toupper,
+	boolean_t is_it_tolower,
+	boolean_t canonical_decomposition,
+	boolean_t compatibility_decomposition,
+	boolean_t canonical_composition,
+	int *errnum, u8_normalization_states_t *state)
+{
+	uchar_t *s;
+	int sz;
+	int saved_sz;
+	size_t i;
+	size_t j;
+	size_t k;
+	size_t l;
+	uchar_t comb_class[U8_MAX_CHARS_A_SEQ];
+	uchar_t disp[U8_MAX_CHARS_A_SEQ];
+	uchar_t start[U8_MAX_CHARS_A_SEQ];
+	uchar_t u8t[U8_MB_CUR_MAX];
+	uchar_t uts[U8_STREAM_SAFE_TEXT_MAX + 1];
+	uchar_t tc;
+	size_t last;
+	size_t saved_last;
+	uint32_t u1;
+
+	/*
+	 * Save the source string pointer which we will return a changed
+	 * pointer if we do processing.
+	 */
+	s = *source;
+
+	/*
+	 * The following is a fallback for just in case callers are not
+	 * checking the string boundaries before the calling.
+	 */
+	if (s >= slast) {
+		u8s[0] = '\0';
+
+		return (0);
+	}
+
+	/*
+	 * As the first thing, let's collect a character and do case
+	 * conversion if necessary.
+	 */
+
+	sz = u8_number_of_bytes[*s];
+
+	if (sz < 0) {
+		*errnum = EILSEQ;
+
+		u8s[0] = *s++;
+		u8s[1] = '\0';
+
+		*source = s;
+
+		return (1);
+	}
+
+	if (sz == 1) {
+		if (is_it_toupper)
+			u8s[0] = U8_ASCII_TOUPPER(*s);
+		else if (is_it_tolower)
+			u8s[0] = U8_ASCII_TOLOWER(*s);
+		else
+			u8s[0] = *s;
+		s++;
+		u8s[1] = '\0';
+	} else if ((s + sz) > slast) {
+		*errnum = EINVAL;
+
+		for (i = 0; s < slast; )
+			u8s[i++] = *s++;
+		u8s[i] = '\0';
+
+		*source = s;
+
+		return (i);
+	} else {
+		if (is_it_toupper || is_it_tolower) {
+			i = do_case_conv(uv, u8s, s, sz, is_it_toupper);
+			s += sz;
+			sz = i;
+		} else {
+			for (i = 0; i < sz; )
+				u8s[i++] = *s++;
+			u8s[i] = '\0';
+		}
+	}
+
+	/*
+	 * And then canonical/compatibility decomposition followed by
+	 * an optional canonical composition. Please be noted that
+	 * canonical composition is done only when a decomposition is
+	 * done.
+	 */
+	if (canonical_decomposition || compatibility_decomposition) {
+		if (sz == 1) {
+			*state = U8_STATE_START;
+
+			saved_sz = 1;
+
+			comb_class[0] = 0;
+			start[0] = 0;
+			disp[0] = 1;
+
+			last = 1;
+		} else {
+			saved_sz = do_decomp(uv, u8s, u8s, sz,
+			    canonical_decomposition, state);
+
+			last = 0;
+
+			for (i = 0; i < saved_sz; ) {
+				sz = u8_number_of_bytes[u8s[i]];
+
+				comb_class[last] = combining_class(uv,
+				    u8s + i, sz);
+				start[last] = i;
+				disp[last] = sz;
+
+				last++;
+				i += sz;
+			}
+
+			/*
+			 * Decomposition yields various Hangul related
+			 * states but not on combining marks. We need to
+			 * find out at here by checking on the last
+			 * character.
+			 */
+			if (*state == U8_STATE_START) {
+				if (comb_class[last - 1])
+					*state = U8_STATE_COMBINING_MARK;
+			}
+		}
+
+		saved_last = last;
+
+		while (s < slast) {
+			sz = u8_number_of_bytes[*s];
+
+			/*
+			 * If this is an illegal character, an incomplete
+			 * character, or an 7-bit ASCII Starter character,
+			 * then we have collected a sequence; break and let
+			 * the next call deal with the two cases.
+			 *
+			 * Note that this is okay only if you are using this
+			 * function with a fixed length string, not on
+			 * a buffer with multiple calls of one chunk at a time.
+			 */
+			if (sz <= 1) {
+				break;
+			} else if ((s + sz) > slast) {
+				break;
+			} else {
+				/*
+				 * If the previous character was a Hangul Jamo
+				 * and this character is a Hangul Jamo that
+				 * can be conjoined, we collect the Jamo.
+				 */
+				if (*s == U8_HANGUL_JAMO_1ST_BYTE) {
+					U8_PUT_3BYTES_INTO_UTF32(u1,
+					    *s, *(s + 1), *(s + 2));
+
+					if (U8_HANGUL_COMPOSABLE_L_V(*state,
+					    u1)) {
+						i = 0;
+						*state = U8_STATE_HANGUL_LV;
+						goto COLLECT_A_HANGUL;
+					}
+
+					if (U8_HANGUL_COMPOSABLE_LV_T(*state,
+					    u1)) {
+						i = 0;
+						*state = U8_STATE_HANGUL_LVT;
+						goto COLLECT_A_HANGUL;
+					}
+				}
+
+				/*
+				 * Regardless of whatever it was, if this is
+				 * a Starter, we don't collect the character
+				 * since that's a new start and we will deal
+				 * with it at the next time.
+				 */
+				i = combining_class(uv, s, sz);
+				if (i == U8_COMBINING_CLASS_STARTER)
+					break;
+
+				/*
+				 * We know the current character is a combining
+				 * mark. If the previous character wasn't
+				 * a Starter (not Hangul) or a combining mark,
+				 * then, we don't collect this combining mark.
+				 */
+				if (*state != U8_STATE_START &&
+				    *state != U8_STATE_COMBINING_MARK)
+					break;
+
+				*state = U8_STATE_COMBINING_MARK;
+COLLECT_A_HANGUL:
+				/*
+				 * If we collected a Starter and combining
+				 * marks up to 30, i.e., total 31 characters,
+				 * then, we terminate this degenerately long
+				 * combining sequence with a U+034F COMBINING
+				 * GRAPHEME JOINER (CGJ) which is 0xCD 0x8F in
+				 * UTF-8 and turn this into a Stream-Safe
+				 * Text. This will be extremely rare but
+				 * possible.
+				 *
+				 * The following will also guarantee that
+				 * we are not writing more than 32 characters
+				 * plus a NULL at u8s[].
+				 */
+				if (last >= U8_UPPER_LIMIT_IN_A_SEQ) {
+TURN_STREAM_SAFE:
+					*state = U8_STATE_START;
+					comb_class[last] = 0;
+					start[last] = saved_sz;
+					disp[last] = 2;
+					last++;
+
+					u8s[saved_sz++] = 0xCD;
+					u8s[saved_sz++] = 0x8F;
+
+					break;
+				}
+
+				/*
+				 * Some combining marks also do decompose into
+				 * another combining mark or marks.
+				 */
+				if (*state == U8_STATE_COMBINING_MARK) {
+					k = last;
+					l = sz;
+					i = do_decomp(uv, uts, s, sz,
+					    canonical_decomposition, state);
+					for (j = 0; j < i; ) {
+						sz = u8_number_of_bytes[uts[j]];
+
+						comb_class[last] =
+						    combining_class(uv,
+						    uts + j, sz);
+						start[last] = saved_sz + j;
+						disp[last] = sz;
+
+						last++;
+						if (last >=
+						    U8_UPPER_LIMIT_IN_A_SEQ) {
+							last = k;
+							goto TURN_STREAM_SAFE;
+						}
+						j += sz;
+					}
+
+					*state = U8_STATE_COMBINING_MARK;
+					sz = i;
+					s += l;
+
+					for (i = 0; i < sz; i++)
+						u8s[saved_sz++] = uts[i];
+				} else {
+					comb_class[last] = i;
+					start[last] = saved_sz;
+					disp[last] = sz;
+					last++;
+
+					for (i = 0; i < sz; i++)
+						u8s[saved_sz++] = *s++;
+				}
+
+				/*
+				 * If this is U+0345 COMBINING GREEK
+				 * YPOGEGRAMMENI (0xCD 0x85 in UTF-8), a.k.a.,
+				 * iota subscript, and need to be converted to
+				 * uppercase letter, convert it to U+0399 GREEK
+				 * CAPITAL LETTER IOTA (0xCE 0x99 in UTF-8),
+				 * i.e., convert to capital adscript form as
+				 * specified in the Unicode standard.
+				 *
+				 * This is the only special case of (ambiguous)
+				 * case conversion at combining marks and
+				 * probably the standard will never have
+				 * anything similar like this in future.
+				 */
+				if (is_it_toupper && sz >= 2 &&
+				    u8s[saved_sz - 2] == 0xCD &&
+				    u8s[saved_sz - 1] == 0x85) {
+					u8s[saved_sz - 2] = 0xCE;
+					u8s[saved_sz - 1] = 0x99;
+				}
+			}
+		}
+
+		/*
+		 * Let's try to ensure a canonical ordering for the collected
+		 * combining marks. We do this only if we have collected
+		 * at least one more non-Starter. (The decomposition mapping
+		 * data tables have fully (and recursively) expanded and
+		 * canonically ordered decompositions.)
+		 *
+		 * The U8_SWAP_COMB_MARKS() convenience macro has some
+		 * assumptions and we are meeting the assumptions.
+		 */
+		last--;
+		if (last >= saved_last) {
+			for (i = 0; i < last; i++)
+				for (j = last; j > i; j--)
+					if (comb_class[j] &&
+					    comb_class[j - 1] > comb_class[j]) {
+						U8_SWAP_COMB_MARKS(j - 1, j);
+					}
+		}
+
+		*source = s;
+
+		if (! canonical_composition) {
+			u8s[saved_sz] = '\0';
+			return (saved_sz);
+		}
+
+		/*
+		 * Now do the canonical composition. Note that we do this
+		 * only after a canonical or compatibility decomposition to
+		 * finish up NFC or NFKC.
+		 */
+		sz = do_composition(uv, u8s, comb_class, start, disp, last,
+		    &s, slast);
+	}
+
+	*source = s;
+
+	return ((size_t)sz);
+}
+
+/*
+ * The do_norm_compare() function does string comparion based on Unicode
+ * simple case mappings and Unicode Normalization definitions.
+ *
+ * It does so by collecting a sequence of character at a time and comparing
+ * the collected sequences from the strings.
+ *
+ * The meanings on the return values are the same as the usual strcmp().
+ */
+static int
+do_norm_compare(size_t uv, uchar_t *s1, uchar_t *s2, size_t n1, size_t n2,
+	int flag, int *errnum)
+{
+	int result;
+	size_t sz1;
+	size_t sz2;
+	uchar_t u8s1[U8_STREAM_SAFE_TEXT_MAX + 1];
+	uchar_t u8s2[U8_STREAM_SAFE_TEXT_MAX + 1];
+	uchar_t *s1last;
+	uchar_t *s2last;
+	boolean_t is_it_toupper;
+	boolean_t is_it_tolower;
+	boolean_t canonical_decomposition;
+	boolean_t compatibility_decomposition;
+	boolean_t canonical_composition;
+	u8_normalization_states_t state;
+
+	s1last = s1 + n1;
+	s2last = s2 + n2;
+
+	is_it_toupper = flag & U8_TEXTPREP_TOUPPER;
+	is_it_tolower = flag & U8_TEXTPREP_TOLOWER;
+	canonical_decomposition = flag & U8_CANON_DECOMP;
+	compatibility_decomposition = flag & U8_COMPAT_DECOMP;
+	canonical_composition = flag & U8_CANON_COMP;
+
+	while (s1 < s1last && s2 < s2last) {
+		/*
+		 * If the current character is a 7-bit ASCII and the last
+		 * character, or, if the current character and the next
+		 * character are both some 7-bit ASCII characters then
+		 * we treat the current character as a sequence.
+		 *
+		 * In any other cases, we need to call collect_a_seq().
+		 */
+
+		if (U8_ISASCII(*s1) && ((s1 + 1) >= s1last ||
+		    ((s1 + 1) < s1last && U8_ISASCII(*(s1 + 1))))) {
+			if (is_it_toupper)
+				u8s1[0] = U8_ASCII_TOUPPER(*s1);
+			else if (is_it_tolower)
+				u8s1[0] = U8_ASCII_TOLOWER(*s1);
+			else
+				u8s1[0] = *s1;
+			u8s1[1] = '\0';
+			sz1 = 1;
+			s1++;
+		} else {
+			state = U8_STATE_START;
+			sz1 = collect_a_seq(uv, u8s1, &s1, s1last,
+			    is_it_toupper, is_it_tolower,
+			    canonical_decomposition,
+			    compatibility_decomposition,
+			    canonical_composition, errnum, &state);
+		}
+
+		if (U8_ISASCII(*s2) && ((s2 + 1) >= s2last ||
+		    ((s2 + 1) < s2last && U8_ISASCII(*(s2 + 1))))) {
+			if (is_it_toupper)
+				u8s2[0] = U8_ASCII_TOUPPER(*s2);
+			else if (is_it_tolower)
+				u8s2[0] = U8_ASCII_TOLOWER(*s2);
+			else
+				u8s2[0] = *s2;
+			u8s2[1] = '\0';
+			sz2 = 1;
+			s2++;
+		} else {
+			state = U8_STATE_START;
+			sz2 = collect_a_seq(uv, u8s2, &s2, s2last,
+			    is_it_toupper, is_it_tolower,
+			    canonical_decomposition,
+			    compatibility_decomposition,
+			    canonical_composition, errnum, &state);
+		}
+
+		/*
+		 * Now compare the two characters. If they are the same,
+		 * we move on to the next character sequences.
+		 */
+		if (sz1 == 1 && sz2 == 1) {
+			if (*u8s1 > *u8s2)
+				return (1);
+			if (*u8s1 < *u8s2)
+				return (-1);
+		} else {
+			result = strcmp((const char *)u8s1, (const char *)u8s2);
+			if (result != 0)
+				return (result);
+		}
+	}
+
+	/*
+	 * We compared until the end of either or both strings.
+	 *
+	 * If we reached to or went over the ends for the both, that means
+	 * they are the same.
+	 *
+	 * If we reached only one end, that means the other string has
+	 * something which then can be used to determine the return value.
+	 */
+	if (s1 >= s1last) {
+		if (s2 >= s2last)
+			return (0);
+		return (-1);
+	}
+	return (1);
+}
+
+/*
+ * The u8_strcmp() function compares two UTF-8 strings quite similar to
+ * the strcmp(). For the comparison, however, Unicode Normalization specific
+ * equivalency and Unicode simple case conversion mappings based equivalency
+ * can be requested and checked against.
+ */
+int
+u8_strcmp(const char *s1, const char *s2, size_t n, int flag, size_t uv,
+		int *errnum)
+{
+	int f;
+	size_t n1;
+	size_t n2;
+
+	*errnum = 0;
+
+	/*
+	 * Check on the requested Unicode version, case conversion, and
+	 * normalization flag values.
+	 */
+
+	if (uv > U8_UNICODE_LATEST) {
+		*errnum = ERANGE;
+		uv = U8_UNICODE_LATEST;
+	}
+
+	if (flag == 0) {
+		flag = U8_STRCMP_CS;
+	} else {
+		f = flag & (U8_STRCMP_CS | U8_STRCMP_CI_UPPER |
+		    U8_STRCMP_CI_LOWER);
+		if (f == 0) {
+			flag |= U8_STRCMP_CS;
+		} else if (f != U8_STRCMP_CS && f != U8_STRCMP_CI_UPPER &&
+		    f != U8_STRCMP_CI_LOWER) {
+			*errnum = EBADF;
+			flag = U8_STRCMP_CS;
+		}
+
+		f = flag & (U8_CANON_DECOMP | U8_COMPAT_DECOMP | U8_CANON_COMP);
+		if (f && f != U8_STRCMP_NFD && f != U8_STRCMP_NFC &&
+		    f != U8_STRCMP_NFKD && f != U8_STRCMP_NFKC) {
+			*errnum = EBADF;
+			flag = U8_STRCMP_CS;
+		}
+	}
+
+	if (flag == U8_STRCMP_CS) {
+		return (n == 0 ? strcmp(s1, s2) : strncmp(s1, s2, n));
+	}
+
+	n1 = strlen(s1);
+	n2 = strlen(s2);
+	if (n != 0) {
+		if (n < n1)
+			n1 = n;
+		if (n < n2)
+			n2 = n;
+	}
+
+	/*
+	 * Simple case conversion can be done much faster and so we do
+	 * them separately here.
+	 */
+	if (flag == U8_STRCMP_CI_UPPER) {
+		return (do_case_compare(uv, (uchar_t *)s1, (uchar_t *)s2,
+		    n1, n2, B_TRUE, errnum));
+	} else if (flag == U8_STRCMP_CI_LOWER) {
+		return (do_case_compare(uv, (uchar_t *)s1, (uchar_t *)s2,
+		    n1, n2, B_FALSE, errnum));
+	}
+
+	return (do_norm_compare(uv, (uchar_t *)s1, (uchar_t *)s2, n1, n2,
+	    flag, errnum));
+}
+
+size_t
+u8_textprep_str(char *inarray, size_t *inlen, char *outarray, size_t *outlen,
+	int flag, size_t unicode_version, int *errnum)
+{
+	int f;
+	int sz;
+	uchar_t *ib;
+	uchar_t *ibtail;
+	uchar_t *ob;
+	uchar_t *obtail;
+	boolean_t do_not_ignore_null;
+	boolean_t do_not_ignore_invalid;
+	boolean_t is_it_toupper;
+	boolean_t is_it_tolower;
+	boolean_t canonical_decomposition;
+	boolean_t compatibility_decomposition;
+	boolean_t canonical_composition;
+	size_t ret_val;
+	size_t i;
+	size_t j;
+	uchar_t u8s[U8_STREAM_SAFE_TEXT_MAX + 1];
+	u8_normalization_states_t state;
+
+	if (unicode_version > U8_UNICODE_LATEST) {
+		*errnum = ERANGE;
+		return ((size_t)-1);
+	}
+
+	f = flag & (U8_TEXTPREP_TOUPPER | U8_TEXTPREP_TOLOWER);
+	if (f == (U8_TEXTPREP_TOUPPER | U8_TEXTPREP_TOLOWER)) {
+		*errnum = EBADF;
+		return ((size_t)-1);
+	}
+
+	f = flag & (U8_CANON_DECOMP | U8_COMPAT_DECOMP | U8_CANON_COMP);
+	if (f && f != U8_TEXTPREP_NFD && f != U8_TEXTPREP_NFC &&
+	    f != U8_TEXTPREP_NFKD && f != U8_TEXTPREP_NFKC) {
+		*errnum = EBADF;
+		return ((size_t)-1);
+	}
+
+	if (inarray == NULL || *inlen == 0)
+		return (0);
+
+	if (outarray == NULL) {
+		*errnum = E2BIG;
+		return ((size_t)-1);
+	}
+
+	ib = (uchar_t *)inarray;
+	ob = (uchar_t *)outarray;
+	ibtail = ib + *inlen;
+	obtail = ob + *outlen;
+
+	do_not_ignore_null = !(flag & U8_TEXTPREP_IGNORE_NULL);
+	do_not_ignore_invalid = !(flag & U8_TEXTPREP_IGNORE_INVALID);
+	is_it_toupper = flag & U8_TEXTPREP_TOUPPER;
+	is_it_tolower = flag & U8_TEXTPREP_TOLOWER;
+
+	ret_val = 0;
+
+	/*
+	 * If we don't have a normalization flag set, we do the simple case
+	 * conversion based text preparation separately below. Text
+	 * preparation involving Normalization will be done in the false task
+	 * block, again, separately since it will take much more time and
+	 * resource than doing simple case conversions.
+	 */
+	if (f == 0) {
+		while (ib < ibtail) {
+			if (*ib == '\0' && do_not_ignore_null)
+				break;
+
+			sz = u8_number_of_bytes[*ib];
+
+			if (sz < 0) {
+				if (do_not_ignore_invalid) {
+					*errnum = EILSEQ;
+					ret_val = (size_t)-1;
+					break;
+				}
+
+				sz = 1;
+				ret_val++;
+			}
+
+			if (sz == 1) {
+				if (ob >= obtail) {
+					*errnum = E2BIG;
+					ret_val = (size_t)-1;
+					break;
+				}
+
+				if (is_it_toupper)
+					*ob = U8_ASCII_TOUPPER(*ib);
+				else if (is_it_tolower)
+					*ob = U8_ASCII_TOLOWER(*ib);
+				else
+					*ob = *ib;
+				ib++;
+				ob++;
+			} else if ((ib + sz) > ibtail) {
+				if (do_not_ignore_invalid) {
+					*errnum = EINVAL;
+					ret_val = (size_t)-1;
+					break;
+				}
+
+				if ((obtail - ob) < (ibtail - ib)) {
+					*errnum = E2BIG;
+					ret_val = (size_t)-1;
+					break;
+				}
+
+				/*
+				 * We treat the remaining incomplete character
+				 * bytes as a character.
+				 */
+				ret_val++;
+
+				while (ib < ibtail)
+					*ob++ = *ib++;
+			} else {
+				if (is_it_toupper || is_it_tolower) {
+					i = do_case_conv(unicode_version, u8s,
+					    ib, sz, is_it_toupper);
+
+					if ((obtail - ob) < i) {
+						*errnum = E2BIG;
+						ret_val = (size_t)-1;
+						break;
+					}
+
+					ib += sz;
+
+					for (sz = 0; sz < i; sz++)
+						*ob++ = u8s[sz];
+				} else {
+					if ((obtail - ob) < sz) {
+						*errnum = E2BIG;
+						ret_val = (size_t)-1;
+						break;
+					}
+
+					for (i = 0; i < sz; i++)
+						*ob++ = *ib++;
+				}
+			}
+		}
+	} else {
+		canonical_decomposition = flag & U8_CANON_DECOMP;
+		compatibility_decomposition = flag & U8_COMPAT_DECOMP;
+		canonical_composition = flag & U8_CANON_COMP;
+
+		while (ib < ibtail) {
+			if (*ib == '\0' && do_not_ignore_null)
+				break;
+
+			/*
+			 * If the current character is a 7-bit ASCII
+			 * character and it is the last character, or,
+			 * if the current character is a 7-bit ASCII
+			 * character and the next character is also a 7-bit
+			 * ASCII character, then, we copy over this
+			 * character without going through collect_a_seq().
+			 *
+			 * In any other cases, we need to look further with
+			 * the collect_a_seq() function.
+			 */
+			if (U8_ISASCII(*ib) && ((ib + 1) >= ibtail ||
+			    ((ib + 1) < ibtail && U8_ISASCII(*(ib + 1))))) {
+				if (ob >= obtail) {
+					*errnum = E2BIG;
+					ret_val = (size_t)-1;
+					break;
+				}
+
+				if (is_it_toupper)
+					*ob = U8_ASCII_TOUPPER(*ib);
+				else if (is_it_tolower)
+					*ob = U8_ASCII_TOLOWER(*ib);
+				else
+					*ob = *ib;
+				ib++;
+				ob++;
+			} else {
+				*errnum = 0;
+				state = U8_STATE_START;
+
+				j = collect_a_seq(unicode_version, u8s,
+				    &ib, ibtail,
+				    is_it_toupper,
+				    is_it_tolower,
+				    canonical_decomposition,
+				    compatibility_decomposition,
+				    canonical_composition,
+				    errnum, &state);
+
+				if (*errnum && do_not_ignore_invalid) {
+					ret_val = (size_t)-1;
+					break;
+				}
+
+				if ((obtail - ob) < j) {
+					*errnum = E2BIG;
+					ret_val = (size_t)-1;
+					break;
+				}
+
+				for (i = 0; i < j; i++)
+					*ob++ = u8s[i];
+			}
+		}
+	}
+
+	*inlen = ibtail - ib;
+	*outlen = obtail - ob;
+
+	return (ret_val);
+}
diff --git a/sys/cddl/contrib/opensolaris/common/zfs/zfs_comutil.c b/sys/cddl/contrib/opensolaris/common/zfs/zfs_comutil.c
new file mode 100644
index 000000000000..74517a3f6920
--- /dev/null
+++ b/sys/cddl/contrib/opensolaris/common/zfs/zfs_comutil.c
@@ -0,0 +1,65 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License (the "License").
+ * You may not use this file except in compliance with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or http://www.opensolaris.org/os/licensing.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+/*
+ * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+ * Use is subject to license terms.
+ */
+
+#pragma ident	"%Z%%M%	%I%	%E% SMI"
+
+/*
+ * This file is intended for functions that ought to be common between user
+ * land (libzfs) and the kernel. When many common routines need to be shared
+ * then a separate file should to be created.
+ */
+
+#if defined(_KERNEL)
+#include <sys/systm.h>
+#endif
+
+#include <sys/types.h>
+#include <sys/fs/zfs.h>
+#include <sys/nvpair.h>
+
+/*
+ * Are there allocatable vdevs?
+ */
+boolean_t
+zfs_allocatable_devs(nvlist_t *nv)
+{
+	uint64_t is_log;
+	uint_t c;
+	nvlist_t **child;
+	uint_t children;
+
+	if (nvlist_lookup_nvlist_array(nv, ZPOOL_CONFIG_CHILDREN,
+	    &child, &children) != 0) {
+		return (B_FALSE);
+	}
+	for (c = 0; c < children; c++) {
+		is_log = 0;
+		(void) nvlist_lookup_uint64(child[c], ZPOOL_CONFIG_IS_LOG,
+		    &is_log);
+		if (!is_log)
+			return (B_TRUE);
+	}
+	return (B_FALSE);
+}
diff --git a/sys/cddl/contrib/opensolaris/common/zfs/zfs_comutil.h b/sys/cddl/contrib/opensolaris/common/zfs/zfs_comutil.h
new file mode 100644
index 000000000000..f517044a80a0
--- /dev/null
+++ b/sys/cddl/contrib/opensolaris/common/zfs/zfs_comutil.h
@@ -0,0 +1,44 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License (the "License").
+ * You may not use this file except in compliance with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or http://www.opensolaris.org/os/licensing.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+/*
+ * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+ * Use is subject to license terms.
+ */
+
+#ifndef	_ZFS_COMUTIL_H
+#define	_ZFS_COMUTIL_H
+
+#pragma ident	"%Z%%M%	%I%	%E% SMI"
+
+#include <sys/fs/zfs.h>
+#include <sys/types.h>
+
+#ifdef	__cplusplus
+extern "C" {
+#endif
+
+extern boolean_t zfs_allocatable_devs(nvlist_t *nv);
+
+#ifdef	__cplusplus
+}
+#endif
+
+#endif	/* _ZFS_COMUTIL_H */
diff --git a/sys/cddl/contrib/opensolaris/common/zfs/zfs_deleg.c b/sys/cddl/contrib/opensolaris/common/zfs/zfs_deleg.c
new file mode 100644
index 000000000000..0fd5800a84dc
--- /dev/null
+++ b/sys/cddl/contrib/opensolaris/common/zfs/zfs_deleg.c
@@ -0,0 +1,234 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License (the "License").
+ * You may not use this file except in compliance with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or http://www.opensolaris.org/os/licensing.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+/*
+ * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+ * Use is subject to license terms.
+ */
+
+
+#pragma ident	"%Z%%M%	%I%	%E% SMI"
+
+#if defined(_KERNEL)
+#include <sys/systm.h>
+#include <sys/sunddi.h>
+#include <sys/ctype.h>
+#else
+#include <stdio.h>
+#include <unistd.h>
+#include <strings.h>
+#include <libnvpair.h>
+#include <ctype.h>
+#endif
+/* XXX includes zfs_context.h, so why bother with the above? */
+#include <sys/dsl_deleg.h>
+#include "zfs_prop.h"
+#include "zfs_deleg.h"
+#include "zfs_namecheck.h"
+
+/*
+ * permission table
+ *
+ * Keep this table in sorted order
+ *
+ * This table is used for displaying all permissions for
+ * zfs allow
+ */
+
+zfs_deleg_perm_tab_t zfs_deleg_perm_tab[] = {
+	{ZFS_DELEG_PERM_ALLOW, ZFS_DELEG_NOTE_ALLOW},
+	{ZFS_DELEG_PERM_CLONE, ZFS_DELEG_NOTE_CLONE },
+	{ZFS_DELEG_PERM_CREATE, ZFS_DELEG_NOTE_CREATE },
+	{ZFS_DELEG_PERM_DESTROY, ZFS_DELEG_NOTE_DESTROY },
+	{ZFS_DELEG_PERM_MOUNT, ZFS_DELEG_NOTE_MOUNT },
+	{ZFS_DELEG_PERM_PROMOTE, ZFS_DELEG_NOTE_PROMOTE },
+	{ZFS_DELEG_PERM_RECEIVE, ZFS_DELEG_NOTE_RECEIVE },
+	{ZFS_DELEG_PERM_RENAME, ZFS_DELEG_NOTE_RENAME },
+	{ZFS_DELEG_PERM_ROLLBACK, ZFS_DELEG_NOTE_ROLLBACK },
+	{ZFS_DELEG_PERM_SNAPSHOT, ZFS_DELEG_NOTE_SNAPSHOT },
+	{ZFS_DELEG_PERM_SHARE, ZFS_DELEG_NOTE_SHARE },
+	{ZFS_DELEG_PERM_SEND, ZFS_DELEG_NOTE_NONE },
+	{ZFS_DELEG_PERM_USERPROP, ZFS_DELEG_NOTE_USERPROP },
+	{NULL, ZFS_DELEG_NOTE_NONE }
+};
+
+static int
+zfs_valid_permission_name(const char *perm)
+{
+	if (zfs_deleg_canonicalize_perm(perm))
+		return (0);
+
+	return (permset_namecheck(perm, NULL, NULL));
+}
+
+const char *
+zfs_deleg_canonicalize_perm(const char *perm)
+{
+	int i;
+	zfs_prop_t prop;
+
+	for (i = 0; zfs_deleg_perm_tab[i].z_perm != NULL; i++) {
+		if (strcmp(perm, zfs_deleg_perm_tab[i].z_perm) == 0)
+			return (perm);
+	}
+
+	prop = zfs_name_to_prop(perm);
+	if (prop != ZPROP_INVAL && zfs_prop_delegatable(prop))
+		return (zfs_prop_to_name(prop));
+	return (NULL);
+
+}
+
+static int
+zfs_validate_who(char *who)
+{
+	char *p;
+
+	if (who[2] != ZFS_DELEG_FIELD_SEP_CHR)
+		return (-1);
+
+	switch (who[0]) {
+	case ZFS_DELEG_USER:
+	case ZFS_DELEG_GROUP:
+	case ZFS_DELEG_USER_SETS:
+	case ZFS_DELEG_GROUP_SETS:
+		if (who[1] != ZFS_DELEG_LOCAL && who[1] != ZFS_DELEG_DESCENDENT)
+			return (-1);
+		for (p = &who[3]; *p; p++)
+			if (!isdigit(*p))
+				return (-1);
+		break;
+
+	case ZFS_DELEG_NAMED_SET:
+	case ZFS_DELEG_NAMED_SET_SETS:
+		if (who[1] != ZFS_DELEG_NA)
+			return (-1);
+		return (permset_namecheck(&who[3], NULL, NULL));
+
+	case ZFS_DELEG_CREATE:
+	case ZFS_DELEG_CREATE_SETS:
+		if (who[1] != ZFS_DELEG_NA)
+			return (-1);
+		if (who[3] != '\0')
+			return (-1);
+		break;
+
+	case ZFS_DELEG_EVERYONE:
+	case ZFS_DELEG_EVERYONE_SETS:
+		if (who[1] != ZFS_DELEG_LOCAL && who[1] != ZFS_DELEG_DESCENDENT)
+			return (-1);
+		if (who[3] != '\0')
+			return (-1);
+		break;
+
+	default:
+		return (-1);
+	}
+
+	return (0);
+}
+
+int
+zfs_deleg_verify_nvlist(nvlist_t *nvp)
+{
+	nvpair_t *who, *perm_name;
+	nvlist_t *perms;
+	int error;
+
+	if (nvp == NULL)
+		return (-1);
+
+	who = nvlist_next_nvpair(nvp, NULL);
+	if (who == NULL)
+		return (-1);
+
+	do {
+		if (zfs_validate_who(nvpair_name(who)))
+			return (-1);
+
+		error = nvlist_lookup_nvlist(nvp, nvpair_name(who), &perms);
+
+		if (error && error != ENOENT)
+			return (-1);
+		if (error == ENOENT)
+			continue;
+
+		perm_name = nvlist_next_nvpair(perms, NULL);
+		if (perm_name == NULL) {
+			return (-1);
+		}
+		do {
+			error = zfs_valid_permission_name(
+			    nvpair_name(perm_name));
+			if (error)
+				return (-1);
+		} while (perm_name = nvlist_next_nvpair(perms, perm_name));
+	} while (who = nvlist_next_nvpair(nvp, who));
+	return (0);
+}
+
+/*
+ * Construct the base attribute name.  The base attribute names
+ * are the "key" to locate the jump objects which contain the actual
+ * permissions.  The base attribute names are encoded based on
+ * type of entry and whether it is a local or descendent permission.
+ *
+ * Arguments:
+ * attr - attribute name return string, attribute is assumed to be
+ *        ZFS_MAX_DELEG_NAME long.
+ * type - type of entry to construct
+ * inheritchr - inheritance type (local,descendent, or NA for create and
+ *                               permission set definitions
+ * data - is either a permission set name or a 64 bit uid/gid.
+ */
+void
+zfs_deleg_whokey(char *attr, zfs_deleg_who_type_t type,
+    char inheritchr, void *data)
+{
+	int len = ZFS_MAX_DELEG_NAME;
+	uint64_t *id = data;
+
+	switch (type) {
+	case ZFS_DELEG_USER:
+	case ZFS_DELEG_GROUP:
+	case ZFS_DELEG_USER_SETS:
+	case ZFS_DELEG_GROUP_SETS:
+		(void) snprintf(attr, len, "%c%c%c%lld", type, inheritchr,
+		    ZFS_DELEG_FIELD_SEP_CHR, (longlong_t)*id);
+		break;
+	case ZFS_DELEG_NAMED_SET_SETS:
+	case ZFS_DELEG_NAMED_SET:
+		(void) snprintf(attr, len, "%c-%c%s", type,
+		    ZFS_DELEG_FIELD_SEP_CHR, (char *)data);
+		break;
+	case ZFS_DELEG_CREATE:
+	case ZFS_DELEG_CREATE_SETS:
+		(void) snprintf(attr, len, "%c-%c", type,
+		    ZFS_DELEG_FIELD_SEP_CHR);
+		break;
+	case ZFS_DELEG_EVERYONE:
+	case ZFS_DELEG_EVERYONE_SETS:
+		(void) snprintf(attr, len, "%c%c%c", type, inheritchr,
+		    ZFS_DELEG_FIELD_SEP_CHR);
+		break;
+	default:
+		ASSERT(!"bad zfs_deleg_who_type_t");
+	}
+}
diff --git a/sys/cddl/contrib/opensolaris/common/zfs/zfs_deleg.h b/sys/cddl/contrib/opensolaris/common/zfs/zfs_deleg.h
new file mode 100644
index 000000000000..561b73e63df4
--- /dev/null
+++ b/sys/cddl/contrib/opensolaris/common/zfs/zfs_deleg.h
@@ -0,0 +1,81 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License (the "License").
+ * You may not use this file except in compliance with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or http://www.opensolaris.org/os/licensing.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+/*
+ * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+ * Use is subject to license terms.
+ */
+
+#ifndef	_ZFS_DELEG_H
+#define	_ZFS_DELEG_H
+
+#pragma ident	"%Z%%M%	%I%	%E% SMI"
+
+#include <sys/fs/zfs.h>
+
+#ifdef	__cplusplus
+extern "C" {
+#endif
+
+#define	ZFS_DELEG_SET_NAME_CHR		'@'		/* set name lead char */
+#define	ZFS_DELEG_FIELD_SEP_CHR		'$'		/* field separator */
+
+/*
+ * Max name length for a delegation attribute
+ */
+#define	ZFS_MAX_DELEG_NAME	128
+
+#define	ZFS_DELEG_LOCAL		'l'
+#define	ZFS_DELEG_DESCENDENT	'd'
+#define	ZFS_DELEG_NA		'-'
+
+typedef enum {
+	ZFS_DELEG_NOTE_CREATE,
+	ZFS_DELEG_NOTE_DESTROY,
+	ZFS_DELEG_NOTE_SNAPSHOT,
+	ZFS_DELEG_NOTE_ROLLBACK,
+	ZFS_DELEG_NOTE_CLONE,
+	ZFS_DELEG_NOTE_PROMOTE,
+	ZFS_DELEG_NOTE_RENAME,
+	ZFS_DELEG_NOTE_RECEIVE,
+	ZFS_DELEG_NOTE_ALLOW,
+	ZFS_DELEG_NOTE_USERPROP,
+	ZFS_DELEG_NOTE_MOUNT,
+	ZFS_DELEG_NOTE_SHARE,
+	ZFS_DELEG_NOTE_NONE
+} zfs_deleg_note_t;
+
+typedef struct zfs_deleg_perm_tab {
+	char *z_perm;
+	zfs_deleg_note_t z_note;
+} zfs_deleg_perm_tab_t;
+
+extern zfs_deleg_perm_tab_t zfs_deleg_perm_tab[];
+
+int zfs_deleg_verify_nvlist(nvlist_t *nvlist);
+void zfs_deleg_whokey(char *attr, zfs_deleg_who_type_t type,
+    char checkflag, void *data);
+const char *zfs_deleg_canonicalize_perm(const char *perm);
+
+#ifdef	__cplusplus
+}
+#endif
+
+#endif	/* _ZFS_DELEG_H */
diff --git a/sys/cddl/contrib/opensolaris/common/zfs/zfs_namecheck.c b/sys/cddl/contrib/opensolaris/common/zfs/zfs_namecheck.c
index 2004d860d329..a9d109be20ab 100644
--- a/sys/cddl/contrib/opensolaris/common/zfs/zfs_namecheck.c
+++ b/sys/cddl/contrib/opensolaris/common/zfs/zfs_namecheck.c
@@ -19,7 +19,7 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
@@ -44,7 +44,9 @@
 #endif
 
 #include <sys/param.h>
+#include <sys/nvpair.h>
 #include "zfs_namecheck.h"
+#include "zfs_deleg.h"
 
 static int
 valid_char(char c)
@@ -52,7 +54,7 @@ valid_char(char c)
 	return ((c >= 'a' && c <= 'z') ||
 	    (c >= 'A' && c <= 'Z') ||
 	    (c >= '0' && c <= '9') ||
-	    c == '-' || c == '_' || c == '.' || c == ':');
+	    c == '-' || c == '_' || c == '.' || c == ':' || c == ' ');
 }
 
 /*
@@ -90,6 +92,32 @@ snapshot_namecheck(const char *path, namecheck_err_t *why, char *what)
 	return (0);
 }
 
+
+/*
+ * Permissions set name must start with the letter '@' followed by the
+ * same character restrictions as snapshot names, except that the name
+ * cannot exceed 64 characters.
+ */
+int
+permset_namecheck(const char *path, namecheck_err_t *why, char *what)
+{
+	if (strlen(path) >= ZFS_PERMSET_MAXLEN) {
+		if (why)
+			*why = NAME_ERR_TOOLONG;
+		return (-1);
+	}
+
+	if (path[0] != '@') {
+		if (why) {
+			*why = NAME_ERR_NO_AT;
+			*what = path[0];
+		}
+		return (-1);
+	}
+
+	return (snapshot_namecheck(&path[1], why, what));
+}
+
 /*
  * Dataset names must be of the following form:
  *
@@ -98,7 +126,10 @@ snapshot_namecheck(const char *path, namecheck_err_t *why, char *what)
  * Where each component is made up of alphanumeric characters plus the following
  * characters:
  *
- * 	[-_.:]
+ * 	[-_.:%]
+ *
+ * We allow '%' here as we use that character internally to create unique
+ * names for temporary clones (for online recv).
  */
 int
 dataset_namecheck(const char *path, namecheck_err_t *why, char *what)
@@ -114,6 +145,7 @@ dataset_namecheck(const char *path, namecheck_err_t *why, char *what)
 	 * If ZFS_MAXNAMELEN value is changed, make sure to cleanup all
 	 * places using MAXNAMELEN.
 	 */
+
 	if (strlen(path) >= MAXNAMELEN) {
 		if (why)
 			*why = NAME_ERR_TOOLONG;
@@ -167,7 +199,7 @@ dataset_namecheck(const char *path, namecheck_err_t *why, char *what)
 
 		/* Validate the contents of this component */
 		while (loc != end) {
-			if (!valid_char(*loc)) {
+			if (!valid_char(*loc) && *loc != '%') {
 				if (why) {
 					*why = NAME_ERR_INVALCHAR;
 					*what = *loc;
@@ -211,6 +243,50 @@ dataset_namecheck(const char *path, namecheck_err_t *why, char *what)
 	}
 }
 
+
+/*
+ * mountpoint names must be of the following form:
+ *
+ *	/[component][/]*[component][/]
+ */
+int
+mountpoint_namecheck(const char *path, namecheck_err_t *why)
+{
+	const char *start, *end;
+
+	/*
+	 * Make sure none of the mountpoint component names are too long.
+	 * If a component name is too long then the mkdir of the mountpoint
+	 * will fail but then the mountpoint property will be set to a value
+	 * that can never be mounted.  Better to fail before setting the prop.
+	 * Extra slashes are OK, they will be tossed by the mountpoint mkdir.
+	 */
+
+	if (path == NULL || *path != '/') {
+		if (why)
+			*why = NAME_ERR_LEADING_SLASH;
+		return (-1);
+	}
+
+	/* Skip leading slash  */
+	start = &path[1];
+	do {
+		end = start;
+		while (*end != '/' && *end != '\0')
+			end++;
+
+		if (end - start >= MAXNAMELEN) {
+			if (why)
+				*why = NAME_ERR_TOOLONG;
+			return (-1);
+		}
+		start = end + 1;
+
+	} while (*end != '\0');
+
+	return (0);
+}
+
 /*
  * For pool names, we have the same set of valid characters as described in
  * dataset names, with the additional restriction that the pool name must begin
diff --git a/sys/cddl/contrib/opensolaris/common/zfs/zfs_namecheck.h b/sys/cddl/contrib/opensolaris/common/zfs/zfs_namecheck.h
index 7e0cda974cc6..ec85e62f72e8 100644
--- a/sys/cddl/contrib/opensolaris/common/zfs/zfs_namecheck.h
+++ b/sys/cddl/contrib/opensolaris/common/zfs/zfs_namecheck.h
@@ -19,7 +19,7 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
@@ -42,12 +42,17 @@ typedef enum {
 	NAME_ERR_RESERVED,		/* entire name is reserved */
 	NAME_ERR_DISKLIKE,		/* reserved disk name (c[0-9].*) */
 	NAME_ERR_TOOLONG,		/* name is too long */
+	NAME_ERR_NO_AT,			/* permission set is missing '@' */
 } namecheck_err_t;
 
+#define	ZFS_PERMSET_MAXLEN	64
+
 int pool_namecheck(const char *, namecheck_err_t *, char *);
 int dataset_namecheck(const char *, namecheck_err_t *, char *);
+int mountpoint_namecheck(const char *, namecheck_err_t *);
 int dataset_name_hidden(const char *);
 int snapshot_namecheck(const char *, namecheck_err_t *, char *);
+int permset_namecheck(const char *, namecheck_err_t *, char *);
 
 #ifdef	__cplusplus
 }
diff --git a/sys/cddl/contrib/opensolaris/common/zfs/zfs_prop.c b/sys/cddl/contrib/opensolaris/common/zfs/zfs_prop.c
index 71256192c092..27a6f2e3dd00 100644
--- a/sys/cddl/contrib/opensolaris/common/zfs/zfs_prop.c
+++ b/sys/cddl/contrib/opensolaris/common/zfs/zfs_prop.c
@@ -19,40 +19,19 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
-#pragma ident	"%Z%%M%	%I%	%E% SMI"
-
-/*
- * Master property table.
- *
- * This table keeps track of all the properties supported by ZFS, and their
- * various attributes.  Not all of these are needed by the kernel, and several
- * are only used by a single libzfs client.  But having them here centralizes
- * all property information in one location.
- *
- * 	name		The human-readable string representing this property
- * 	proptype	Basic type (string, boolean, number)
- * 	default		Default value for the property.  Sadly, C only allows
- * 			you to initialize the first member of a union, so we
- * 			have two default members for each property.
- * 	attr		Attributes (readonly, inheritable) for the property
- * 	types		Valid dataset types to which this applies
- * 	values		String describing acceptable values for the property
- * 	colname		The column header for 'zfs list'
- *	colfmt		The column formatting for 'zfs list'
- *
- * This table must match the order of property types in libzfs.h.
- */
-
 #include <sys/zio.h>
 #include <sys/spa.h>
+#include <sys/u8_textprep.h>
 #include <sys/zfs_acl.h>
 #include <sys/zfs_ioctl.h>
+#include <sys/zfs_znode.h>
 
 #include "zfs_prop.h"
+#include "zfs_deleg.h"
 
 #if defined(_KERNEL)
 #include <sys/systm.h>
@@ -62,244 +41,283 @@
 #include <ctype.h>
 #endif
 
-typedef enum {
-	prop_default,
-	prop_readonly,
-	prop_inherit
-} prop_attr_t;
-
-typedef struct {
-	const char	*pd_name;
-	zfs_proptype_t	pd_proptype;
-	uint64_t	pd_numdefault;
-	const char	*pd_strdefault;
-	prop_attr_t	pd_attr;
-	int		pd_types;
-	const char	*pd_values;
-	const char	*pd_colname;
-	boolean_t	pd_rightalign;
-	boolean_t	pd_visible;
-} prop_desc_t;
-
-static prop_desc_t zfs_prop_table[] = {
-	{ "type",	prop_type_string,	0,	NULL,	prop_readonly,
-	    ZFS_TYPE_ANY, "filesystem | volume | snapshot", "TYPE", B_TRUE,
-	    B_TRUE },
-	{ "creation",	prop_type_number,	0,	NULL,	prop_readonly,
-	    ZFS_TYPE_ANY, "<date>", "CREATION", B_FALSE, B_TRUE },
-	{ "used",	prop_type_number,	0,	NULL,	prop_readonly,
-	    ZFS_TYPE_ANY, "<size>",	"USED", B_TRUE, B_TRUE },
-	{ "available",	prop_type_number,	0,	NULL,	prop_readonly,
-	    ZFS_TYPE_FILESYSTEM | ZFS_TYPE_VOLUME, "<size>", "AVAIL", B_TRUE,
-	    B_TRUE },
-	{ "referenced",	prop_type_number,	0,	NULL,	prop_readonly,
-	    ZFS_TYPE_ANY,
-	    "<size>", "REFER", B_TRUE, B_TRUE },
-	{ "compressratio", prop_type_number,	0,	NULL,	prop_readonly,
-	    ZFS_TYPE_ANY, "<1.00x or higher if compressed>", "RATIO", B_TRUE,
-	    B_TRUE },
-	{ "mounted",	prop_type_boolean,	0,	NULL,	prop_readonly,
-	    ZFS_TYPE_FILESYSTEM, "yes | no | -", "MOUNTED", B_TRUE, B_TRUE },
-	{ "origin",	prop_type_string,	0,	NULL,	prop_readonly,
-	    ZFS_TYPE_FILESYSTEM | ZFS_TYPE_VOLUME, "<snapshot>", "ORIGIN",
-	    B_FALSE, B_TRUE },
-	{ "quota",	prop_type_number,	0,	NULL,	prop_default,
-	    ZFS_TYPE_FILESYSTEM, "<size> | none", "QUOTA", B_TRUE, B_TRUE },
-	{ "reservation", prop_type_number,	0,	NULL,	prop_default,
-	    ZFS_TYPE_FILESYSTEM | ZFS_TYPE_VOLUME,
-	    "<size> | none", "RESERV", B_TRUE, B_TRUE },
-	{ "volsize",	prop_type_number,	0,	NULL,	prop_default,
-	    ZFS_TYPE_VOLUME, "<size>", "VOLSIZE", B_TRUE, B_TRUE },
-	{ "volblocksize", prop_type_number,	8192,	NULL,	prop_readonly,
-	    ZFS_TYPE_VOLUME, "512 to 128k, power of 2",	"VOLBLOCK", B_TRUE,
-	    B_TRUE },
-	{ "recordsize",	prop_type_number,	SPA_MAXBLOCKSIZE,	NULL,
-	    prop_inherit,
-	    ZFS_TYPE_FILESYSTEM,
-	    "512 to 128k, power of 2", "RECSIZE", B_TRUE, B_TRUE },
-	{ "mountpoint",	prop_type_string,	0,	"/",	prop_inherit,
-	    ZFS_TYPE_FILESYSTEM,
-	    "<path> | legacy | none", "MOUNTPOINT", B_FALSE, B_TRUE },
-	{ "sharenfs",	prop_type_string,	0,	"off",	prop_inherit,
-	    ZFS_TYPE_FILESYSTEM,
-	    "on | off | exports(5) options", "SHARENFS", B_FALSE, B_TRUE },
-	{ "checksum",	prop_type_index,	ZIO_CHECKSUM_DEFAULT,	"on",
-	    prop_inherit,	ZFS_TYPE_FILESYSTEM | ZFS_TYPE_VOLUME,
-	    "on | off | fletcher2 | fletcher4 | sha256", "CHECKSUM", B_TRUE,
-	    B_TRUE },
-	{ "compression", prop_type_index,	ZIO_COMPRESS_DEFAULT,	"off",
-	    prop_inherit,	ZFS_TYPE_FILESYSTEM | ZFS_TYPE_VOLUME,
-	    "on | off | lzjb | gzip | gzip-[1-9]", "COMPRESS", B_TRUE, B_TRUE },
-	{ "atime",	prop_type_boolean,	1,	NULL,	prop_inherit,
-	    ZFS_TYPE_FILESYSTEM,
-	    "on | off", "ATIME", B_TRUE, B_TRUE },
-	{ "devices",	prop_type_boolean,	1,	NULL,	prop_inherit,
-	    ZFS_TYPE_FILESYSTEM | ZFS_TYPE_SNAPSHOT,
-	    "on | off", "DEVICES", B_TRUE, B_TRUE },
-	{ "exec",	prop_type_boolean,	1,	NULL,	prop_inherit,
-	    ZFS_TYPE_FILESYSTEM | ZFS_TYPE_SNAPSHOT,
-	    "on | off", "EXEC", B_TRUE, B_TRUE },
-	{ "setuid",	prop_type_boolean,	1,	NULL,	prop_inherit,
-	    ZFS_TYPE_FILESYSTEM | ZFS_TYPE_SNAPSHOT, "on | off", "SETUID",
-	    B_TRUE, B_TRUE },
-	{ "readonly",	prop_type_boolean,	0,	NULL,	prop_inherit,
-	    ZFS_TYPE_FILESYSTEM | ZFS_TYPE_VOLUME,
-	    "on | off", "RDONLY", B_TRUE, B_TRUE },
-	{ "jailed",	prop_type_boolean,	0,	NULL,	prop_inherit,
-	    ZFS_TYPE_FILESYSTEM,
-	    "on | off", "JAILED", B_TRUE, B_TRUE },
-	{ "snapdir",	prop_type_index,	ZFS_SNAPDIR_HIDDEN, "hidden",
-	    prop_inherit,
-	    ZFS_TYPE_FILESYSTEM,
-	    "hidden | visible", "SNAPDIR", B_TRUE, B_TRUE },
-	{ "aclmode", prop_type_index,	ZFS_ACL_GROUPMASK, "groupmask",
-	    prop_inherit, ZFS_TYPE_FILESYSTEM,
-	    "discard | groupmask | passthrough", "ACLMODE", B_TRUE, B_TRUE },
-	{ "aclinherit", prop_type_index,	ZFS_ACL_SECURE,	"secure",
-	    prop_inherit, ZFS_TYPE_FILESYSTEM,
-	    "discard | noallow | secure | passthrough", "ACLINHERIT", B_TRUE,
-	    B_TRUE },
-	{ "createtxg",	prop_type_number,	0,	NULL,	prop_readonly,
-	    ZFS_TYPE_ANY, NULL, NULL, B_FALSE, B_FALSE },
-	{ "name",	prop_type_string,	0,	NULL,	prop_readonly,
-	    ZFS_TYPE_ANY, NULL, "NAME", B_FALSE, B_FALSE },
-	{ "canmount",	prop_type_boolean,	1,	NULL,	prop_default,
-	    ZFS_TYPE_FILESYSTEM,
-	    "on | off", "CANMOUNT", B_TRUE, B_TRUE },
-	{ "shareiscsi",	prop_type_string,	0,	"off",	prop_inherit,
-	    ZFS_TYPE_ANY,
-	    "on | off | type=<type>", "SHAREISCSI", B_FALSE, B_TRUE },
-	{ "iscsioptions", prop_type_string,	0,	NULL,	prop_inherit,
-	    ZFS_TYPE_VOLUME, NULL, "ISCSIOPTIONS", B_FALSE, B_FALSE },
-	{ "xattr",	prop_type_boolean,	1,	NULL,	prop_inherit,
-	    ZFS_TYPE_FILESYSTEM | ZFS_TYPE_SNAPSHOT,
-	    "on | off", "XATTR", B_TRUE, B_TRUE },
-	{ "numclones", prop_type_number,	0,	NULL,	prop_readonly,
-	    ZFS_TYPE_SNAPSHOT, NULL, NULL, B_FALSE, B_FALSE },
-	{ "copies",	prop_type_index,	1,	"1",	prop_inherit,
-	    ZFS_TYPE_FILESYSTEM | ZFS_TYPE_VOLUME,
-	    "1 | 2 | 3", "COPIES", B_TRUE, B_TRUE },
-	{ "bootfs", prop_type_string,	0,	NULL,	prop_default,
-	    ZFS_TYPE_POOL, "<filesystem>", "BOOTFS", B_FALSE, B_TRUE },
-};
-
-#define	ZFS_PROP_COUNT	((sizeof (zfs_prop_table))/(sizeof (prop_desc_t)))
-
-/*
- * Returns TRUE if the property applies to the given dataset types.
- */
-int
-zfs_prop_valid_for_type(zfs_prop_t prop, int types)
-{
-	return ((zfs_prop_table[prop].pd_types & types) != 0);
-}
-
-/*
- * Determine if the specified property is visible or not.
- */
-boolean_t
-zfs_prop_is_visible(zfs_prop_t prop)
-{
-	if (prop < 0)
-		return (B_FALSE);
-
-	return (zfs_prop_table[prop].pd_visible);
-}
-
-/*
- * Iterate over all properties, calling back into the specified function
- * for each property. We will continue to iterate until we either
- * reach the end or the callback function something other than
- * ZFS_PROP_CONT.
- */
-zfs_prop_t
-zfs_prop_iter_common(zfs_prop_f func, void *cb, zfs_type_t type,
-    boolean_t show_all)
-{
-	int i;
-
-	for (i = 0; i < ZFS_PROP_COUNT; i++) {
-		if (zfs_prop_valid_for_type(i, type) &&
-		    (zfs_prop_is_visible(i) || show_all)) {
-			if (func(i, cb) != ZFS_PROP_CONT)
-				return (i);
-		}
-	}
-	return (ZFS_PROP_CONT);
-}
+static zprop_desc_t zfs_prop_table[ZFS_NUM_PROPS];
 
-zfs_prop_t
-zfs_prop_iter(zfs_prop_f func, void *cb, boolean_t show_all)
+zprop_desc_t *
+zfs_prop_get_table(void)
 {
-	return (zfs_prop_iter_common(func, cb, ZFS_TYPE_ANY, show_all));
+	return (zfs_prop_table);
 }
 
-zpool_prop_t
-zpool_prop_iter(zpool_prop_f func, void *cb, boolean_t show_all)
+void
+zfs_prop_init(void)
 {
-	return (zfs_prop_iter_common(func, cb, ZFS_TYPE_POOL, show_all));
-}
+	static zprop_index_t checksum_table[] = {
+		{ "on",		ZIO_CHECKSUM_ON },
+		{ "off",	ZIO_CHECKSUM_OFF },
+		{ "fletcher2",	ZIO_CHECKSUM_FLETCHER_2 },
+		{ "fletcher4",	ZIO_CHECKSUM_FLETCHER_4 },
+		{ "sha256",	ZIO_CHECKSUM_SHA256 },
+		{ NULL }
+	};
+
+	static zprop_index_t compress_table[] = {
+		{ "on",		ZIO_COMPRESS_ON },
+		{ "off",	ZIO_COMPRESS_OFF },
+		{ "lzjb",	ZIO_COMPRESS_LZJB },
+		{ "gzip",	ZIO_COMPRESS_GZIP_6 },	/* gzip default */
+		{ "gzip-1",	ZIO_COMPRESS_GZIP_1 },
+		{ "gzip-2",	ZIO_COMPRESS_GZIP_2 },
+		{ "gzip-3",	ZIO_COMPRESS_GZIP_3 },
+		{ "gzip-4",	ZIO_COMPRESS_GZIP_4 },
+		{ "gzip-5",	ZIO_COMPRESS_GZIP_5 },
+		{ "gzip-6",	ZIO_COMPRESS_GZIP_6 },
+		{ "gzip-7",	ZIO_COMPRESS_GZIP_7 },
+		{ "gzip-8",	ZIO_COMPRESS_GZIP_8 },
+		{ "gzip-9",	ZIO_COMPRESS_GZIP_9 },
+		{ NULL }
+	};
+
+	static zprop_index_t snapdir_table[] = {
+		{ "hidden",	ZFS_SNAPDIR_HIDDEN },
+		{ "visible",	ZFS_SNAPDIR_VISIBLE },
+		{ NULL }
+	};
+
+	static zprop_index_t acl_mode_table[] = {
+		{ "discard",	ZFS_ACL_DISCARD },
+		{ "groupmask",	ZFS_ACL_GROUPMASK },
+		{ "passthrough", ZFS_ACL_PASSTHROUGH },
+		{ NULL }
+	};
+
+	static zprop_index_t acl_inherit_table[] = {
+		{ "discard",	ZFS_ACL_DISCARD },
+		{ "noallow",	ZFS_ACL_NOALLOW },
+		{ "restricted",	ZFS_ACL_RESTRICTED },
+		{ "passthrough", ZFS_ACL_PASSTHROUGH },
+		{ "secure",	ZFS_ACL_RESTRICTED }, /* bkwrd compatability */
+		{ NULL }
+	};
+
+	static zprop_index_t case_table[] = {
+		{ "sensitive",		ZFS_CASE_SENSITIVE },
+		{ "insensitive",	ZFS_CASE_INSENSITIVE },
+		{ "mixed",		ZFS_CASE_MIXED },
+		{ NULL }
+	};
+
+	static zprop_index_t copies_table[] = {
+		{ "1",		1 },
+		{ "2",		2 },
+		{ "3",		3 },
+		{ NULL }
+	};
 
-zfs_proptype_t
-zfs_prop_get_type(zfs_prop_t prop)
-{
-	return (zfs_prop_table[prop].pd_proptype);
-}
-
-static boolean_t
-propname_match(const char *p, zfs_prop_t prop, size_t len)
-{
-	const char *propname = zfs_prop_table[prop].pd_name;
-#ifndef _KERNEL
-	const char *colname = zfs_prop_table[prop].pd_colname;
-	int c;
-#endif
-
-#ifndef _KERNEL
-	if (colname == NULL)
-		return (B_FALSE);
-#endif
-
-	if (len == strlen(propname) &&
-	    strncmp(p, propname, len) == 0)
-		return (B_TRUE);
-
-#ifndef _KERNEL
-	if (len != strlen(colname))
-		return (B_FALSE);
-
-	for (c = 0; c < len; c++)
-		if (p[c] != tolower(colname[c]))
-			break;
-
-	return (colname[c] == '\0');
-#else
-	return (B_FALSE);
-#endif
-}
-
-zfs_prop_t
-zfs_name_to_prop_cb(zfs_prop_t prop, void *cb_data)
-{
-	const char *propname = cb_data;
-
-	if (propname_match(propname, prop, strlen(propname)))
-		return (prop);
-
-	return (ZFS_PROP_CONT);
+	/*
+	 * Use the unique flags we have to send to u8_strcmp() and/or
+	 * u8_textprep() to represent the various normalization property
+	 * values.
+	 */
+	static zprop_index_t normalize_table[] = {
+		{ "none",	0 },
+		{ "formD",	U8_TEXTPREP_NFD },
+		{ "formKC",	U8_TEXTPREP_NFKC },
+		{ "formC",	U8_TEXTPREP_NFC },
+		{ "formKD",	U8_TEXTPREP_NFKD },
+		{ NULL }
+	};
+
+	static zprop_index_t version_table[] = {
+		{ "1",		1 },
+		{ "2",		2 },
+		{ "3",		3 },
+		{ "current",	ZPL_VERSION },
+		{ NULL }
+	};
+
+	static zprop_index_t boolean_table[] = {
+		{ "off",	0 },
+		{ "on",		1 },
+		{ NULL }
+	};
+
+	static zprop_index_t canmount_table[] = {
+		{ "off",	ZFS_CANMOUNT_OFF },
+		{ "on",		ZFS_CANMOUNT_ON },
+		{ "noauto",	ZFS_CANMOUNT_NOAUTO },
+		{ NULL }
+	};
+
+	static zprop_index_t cache_table[] = {
+		{ "none",	ZFS_CACHE_NONE },
+		{ "metadata",	ZFS_CACHE_METADATA },
+		{ "all",	ZFS_CACHE_ALL },
+		{ NULL }
+	};
+
+	/* inherit index properties */
+	register_index(ZFS_PROP_CHECKSUM, "checksum", ZIO_CHECKSUM_DEFAULT,
+	    PROP_INHERIT, ZFS_TYPE_FILESYSTEM | ZFS_TYPE_VOLUME,
+	    "on | off | fletcher2 | fletcher4 | sha256", "CHECKSUM",
+	    checksum_table);
+	register_index(ZFS_PROP_COMPRESSION, "compression",
+	    ZIO_COMPRESS_DEFAULT, PROP_INHERIT,
+	    ZFS_TYPE_FILESYSTEM | ZFS_TYPE_VOLUME,
+	    "on | off | lzjb | gzip | gzip-[1-9]", "COMPRESS", compress_table);
+	register_index(ZFS_PROP_SNAPDIR, "snapdir", ZFS_SNAPDIR_HIDDEN,
+	    PROP_INHERIT, ZFS_TYPE_FILESYSTEM,
+	    "hidden | visible", "SNAPDIR", snapdir_table);
+	register_index(ZFS_PROP_ACLMODE, "aclmode", ZFS_ACL_GROUPMASK,
+	    PROP_INHERIT, ZFS_TYPE_FILESYSTEM,
+	    "discard | groupmask | passthrough", "ACLMODE", acl_mode_table);
+	register_index(ZFS_PROP_ACLINHERIT, "aclinherit", ZFS_ACL_RESTRICTED,
+	    PROP_INHERIT, ZFS_TYPE_FILESYSTEM,
+	    "discard | noallow | restricted | passthrough",
+	    "ACLINHERIT", acl_inherit_table);
+	register_index(ZFS_PROP_COPIES, "copies", 1,
+	    PROP_INHERIT, ZFS_TYPE_FILESYSTEM | ZFS_TYPE_VOLUME,
+	    "1 | 2 | 3", "COPIES", copies_table);
+	register_index(ZFS_PROP_PRIMARYCACHE, "primarycache",
+	    ZFS_CACHE_ALL, PROP_INHERIT,
+	    ZFS_TYPE_FILESYSTEM | ZFS_TYPE_SNAPSHOT | ZFS_TYPE_VOLUME,
+	    "all | none | metadata", "PRIMARYCACHE", cache_table);
+	register_index(ZFS_PROP_SECONDARYCACHE, "secondarycache",
+	    ZFS_CACHE_ALL, PROP_INHERIT,
+	    ZFS_TYPE_FILESYSTEM | ZFS_TYPE_SNAPSHOT | ZFS_TYPE_VOLUME,
+	    "all | none | metadata", "SECONDARYCACHE", cache_table);
+
+	/* inherit index (boolean) properties */
+	register_index(ZFS_PROP_ATIME, "atime", 1, PROP_INHERIT,
+	    ZFS_TYPE_FILESYSTEM, "on | off", "ATIME", boolean_table);
+	register_index(ZFS_PROP_DEVICES, "devices", 1, PROP_INHERIT,
+	    ZFS_TYPE_FILESYSTEM | ZFS_TYPE_SNAPSHOT, "on | off", "DEVICES",
+	    boolean_table);
+	register_index(ZFS_PROP_EXEC, "exec", 1, PROP_INHERIT,
+	    ZFS_TYPE_FILESYSTEM | ZFS_TYPE_SNAPSHOT, "on | off", "EXEC",
+	    boolean_table);
+	register_index(ZFS_PROP_SETUID, "setuid", 1, PROP_INHERIT,
+	    ZFS_TYPE_FILESYSTEM | ZFS_TYPE_SNAPSHOT, "on | off", "SETUID",
+	    boolean_table);
+	register_index(ZFS_PROP_READONLY, "readonly", 0, PROP_INHERIT,
+	    ZFS_TYPE_FILESYSTEM | ZFS_TYPE_VOLUME, "on | off", "RDONLY",
+	    boolean_table);
+	register_index(ZFS_PROP_ZONED, "jailed", 0, PROP_INHERIT,
+	    ZFS_TYPE_FILESYSTEM, "on | off", "JAILED", boolean_table);
+	register_index(ZFS_PROP_XATTR, "xattr", 1, PROP_INHERIT,
+	    ZFS_TYPE_FILESYSTEM | ZFS_TYPE_SNAPSHOT, "on | off", "XATTR",
+	    boolean_table);
+	register_index(ZFS_PROP_VSCAN, "vscan", 0, PROP_INHERIT,
+	    ZFS_TYPE_FILESYSTEM, "on | off", "VSCAN",
+	    boolean_table);
+	register_index(ZFS_PROP_NBMAND, "nbmand", 0, PROP_INHERIT,
+	    ZFS_TYPE_FILESYSTEM | ZFS_TYPE_SNAPSHOT, "on | off", "NBMAND",
+	    boolean_table);
+
+	/* default index properties */
+	register_index(ZFS_PROP_VERSION, "version", 0, PROP_DEFAULT,
+	    ZFS_TYPE_FILESYSTEM | ZFS_TYPE_SNAPSHOT,
+	    "1 | 2 | 3 | current", "VERSION", version_table);
+	register_index(ZFS_PROP_CANMOUNT, "canmount", ZFS_CANMOUNT_ON,
+	    PROP_DEFAULT, ZFS_TYPE_FILESYSTEM, "on | off | noauto",
+	    "CANMOUNT", canmount_table);
+
+	/* readonly index (boolean) properties */
+	register_index(ZFS_PROP_MOUNTED, "mounted", 0, PROP_READONLY,
+	    ZFS_TYPE_FILESYSTEM, "yes | no", "MOUNTED", boolean_table);
+
+	/* set once index properties */
+	register_index(ZFS_PROP_NORMALIZE, "normalization", 0,
+	    PROP_ONETIME, ZFS_TYPE_FILESYSTEM | ZFS_TYPE_SNAPSHOT,
+	    "none | formC | formD | formKC | formKD", "NORMALIZATION",
+	    normalize_table);
+	register_index(ZFS_PROP_CASE, "casesensitivity", ZFS_CASE_SENSITIVE,
+	    PROP_ONETIME, ZFS_TYPE_FILESYSTEM | ZFS_TYPE_SNAPSHOT,
+	    "sensitive | insensitive | mixed", "CASE", case_table);
+
+	/* set once index (boolean) properties */
+	register_index(ZFS_PROP_UTF8ONLY, "utf8only", 0, PROP_ONETIME,
+	    ZFS_TYPE_FILESYSTEM | ZFS_TYPE_SNAPSHOT,
+	    "on | off", "UTF8ONLY", boolean_table);
+
+	/* string properties */
+	register_string(ZFS_PROP_ORIGIN, "origin", NULL, PROP_READONLY,
+	    ZFS_TYPE_FILESYSTEM | ZFS_TYPE_VOLUME, "<snapshot>", "ORIGIN");
+	register_string(ZFS_PROP_MOUNTPOINT, "mountpoint", "/", PROP_INHERIT,
+	    ZFS_TYPE_FILESYSTEM, "<path> | legacy | none", "MOUNTPOINT");
+	register_string(ZFS_PROP_SHARENFS, "sharenfs", "off", PROP_INHERIT,
+	    ZFS_TYPE_FILESYSTEM, "on | off | share(1M) options", "SHARENFS");
+	register_string(ZFS_PROP_SHAREISCSI, "shareiscsi", "off", PROP_INHERIT,
+	    ZFS_TYPE_DATASET, "on | off | type=<type>", "SHAREISCSI");
+	register_string(ZFS_PROP_TYPE, "type", NULL, PROP_READONLY,
+	    ZFS_TYPE_DATASET, "filesystem | volume | snapshot", "TYPE");
+	register_string(ZFS_PROP_SHARESMB, "sharesmb", "off", PROP_INHERIT,
+	    ZFS_TYPE_FILESYSTEM, "on | off | sharemgr(1M) options", "SHARESMB");
+
+	/* readonly number properties */
+	register_number(ZFS_PROP_USED, "used", 0, PROP_READONLY,
+	    ZFS_TYPE_DATASET, "<size>", "USED");
+	register_number(ZFS_PROP_AVAILABLE, "available", 0, PROP_READONLY,
+	    ZFS_TYPE_FILESYSTEM | ZFS_TYPE_VOLUME, "<size>", "AVAIL");
+	register_number(ZFS_PROP_REFERENCED, "referenced", 0, PROP_READONLY,
+	    ZFS_TYPE_DATASET, "<size>", "REFER");
+	register_number(ZFS_PROP_COMPRESSRATIO, "compressratio", 0,
+	    PROP_READONLY, ZFS_TYPE_DATASET,
+	    "<1.00x or higher if compressed>", "RATIO");
+	register_number(ZFS_PROP_VOLBLOCKSIZE, "volblocksize", 8192,
+	    PROP_ONETIME,
+	    ZFS_TYPE_VOLUME, "512 to 128k, power of 2",	"VOLBLOCK");
+	register_number(ZFS_PROP_USEDSNAP, "usedbysnapshots", 0, PROP_READONLY,
+	    ZFS_TYPE_FILESYSTEM | ZFS_TYPE_VOLUME, "<size>", "USEDSNAP");
+	register_number(ZFS_PROP_USEDDS, "usedbydataset", 0, PROP_READONLY,
+	    ZFS_TYPE_FILESYSTEM | ZFS_TYPE_VOLUME, "<size>", "USEDDS");
+	register_number(ZFS_PROP_USEDCHILD, "usedbychildren", 0, PROP_READONLY,
+	    ZFS_TYPE_FILESYSTEM | ZFS_TYPE_VOLUME, "<size>", "USEDCHILD");
+	register_number(ZFS_PROP_USEDREFRESERV, "usedbyrefreservation", 0,
+	    PROP_READONLY,
+	    ZFS_TYPE_FILESYSTEM | ZFS_TYPE_VOLUME, "<size>", "USEDREFRESERV");
+
+	/* default number properties */
+	register_number(ZFS_PROP_QUOTA, "quota", 0, PROP_DEFAULT,
+	    ZFS_TYPE_FILESYSTEM, "<size> | none", "QUOTA");
+	register_number(ZFS_PROP_RESERVATION, "reservation", 0, PROP_DEFAULT,
+	    ZFS_TYPE_FILESYSTEM | ZFS_TYPE_VOLUME, "<size> | none", "RESERV");
+	register_number(ZFS_PROP_VOLSIZE, "volsize", 0, PROP_DEFAULT,
+	    ZFS_TYPE_VOLUME, "<size>", "VOLSIZE");
+	register_number(ZFS_PROP_REFQUOTA, "refquota", 0, PROP_DEFAULT,
+	    ZFS_TYPE_FILESYSTEM, "<size> | none", "REFQUOTA");
+	register_number(ZFS_PROP_REFRESERVATION, "refreservation", 0,
+	    PROP_DEFAULT, ZFS_TYPE_FILESYSTEM | ZFS_TYPE_VOLUME,
+	    "<size> | none", "REFRESERV");
+
+	/* inherit number properties */
+	register_number(ZFS_PROP_RECORDSIZE, "recordsize", SPA_MAXBLOCKSIZE,
+	    PROP_INHERIT,
+	    ZFS_TYPE_FILESYSTEM, "512 to 128k, power of 2", "RECSIZE");
+
+	/* hidden properties */
+	register_hidden(ZFS_PROP_CREATETXG, "createtxg", PROP_TYPE_NUMBER,
+	    PROP_READONLY, ZFS_TYPE_DATASET, NULL);
+	register_hidden(ZFS_PROP_NUMCLONES, "numclones", PROP_TYPE_NUMBER,
+	    PROP_READONLY, ZFS_TYPE_SNAPSHOT, NULL);
+	register_hidden(ZFS_PROP_NAME, "name", PROP_TYPE_STRING,
+	    PROP_READONLY, ZFS_TYPE_DATASET, "NAME");
+	register_hidden(ZFS_PROP_ISCSIOPTIONS, "iscsioptions", PROP_TYPE_STRING,
+	    PROP_INHERIT, ZFS_TYPE_VOLUME, "ISCSIOPTIONS");
+	register_hidden(ZFS_PROP_GUID, "guid", PROP_TYPE_NUMBER, PROP_READONLY,
+	    ZFS_TYPE_DATASET, "GUID");
+
+	/* oddball properties */
+	register_impl(ZFS_PROP_CREATION, "creation", PROP_TYPE_NUMBER, 0, NULL,
+	    PROP_READONLY, ZFS_TYPE_DATASET,
+	    "<date>", "CREATION", B_FALSE, B_TRUE, NULL);
 }
 
-/*
- * Given a property name and its type, returns the corresponding property ID.
- */
-zfs_prop_t
-zfs_name_to_prop_common(const char *propname, zfs_type_t type)
+boolean_t
+zfs_prop_delegatable(zfs_prop_t prop)
 {
-	zfs_prop_t prop;
-
-	prop = zfs_prop_iter_common(zfs_name_to_prop_cb, (void *)propname,
-	    type, B_TRUE);
-	return (prop == ZFS_PROP_CONT ? ZFS_PROP_INVAL : prop);
+	zprop_desc_t *pd = &zfs_prop_table[prop];
+	return (pd->pd_attr != PROP_READONLY);
 }
 
 /*
@@ -308,17 +326,9 @@ zfs_name_to_prop_common(const char *propname, zfs_type_t type)
 zfs_prop_t
 zfs_name_to_prop(const char *propname)
 {
-	return (zfs_name_to_prop_common(propname, ZFS_TYPE_ANY));
+	return (zprop_name_to_prop(propname, ZFS_TYPE_DATASET));
 }
 
-/*
- * Given a pool property name, returns the corresponding property ID.
- */
-zpool_prop_t
-zpool_name_to_prop(const char *propname)
-{
-	return (zfs_name_to_prop_common(propname, ZFS_TYPE_POOL));
-}
 
 /*
  * For user property names, we allow all lowercase alphanumeric characters, plus
@@ -357,179 +367,85 @@ zfs_prop_user(const char *name)
 }
 
 /*
- * Return the default value for the given property.
+ * Tables of index types, plus functions to convert between the user view
+ * (strings) and internal representation (uint64_t).
  */
-const char *
-zfs_prop_default_string(zfs_prop_t prop)
+int
+zfs_prop_string_to_index(zfs_prop_t prop, const char *string, uint64_t *index)
 {
-	return (zfs_prop_table[prop].pd_strdefault);
+	return (zprop_string_to_index(prop, string, index, ZFS_TYPE_DATASET));
 }
 
-uint64_t
-zfs_prop_default_numeric(zfs_prop_t prop)
+int
+zfs_prop_index_to_string(zfs_prop_t prop, uint64_t index, const char **string)
 {
-	return (zfs_prop_table[prop].pd_numdefault);
+	return (zprop_index_to_string(prop, index, string, ZFS_TYPE_DATASET));
 }
 
 /*
- * Returns TRUE if the property is readonly.
+ * Returns TRUE if the property applies to any of the given dataset types.
  */
-int
-zfs_prop_readonly(zfs_prop_t prop)
+boolean_t
+zfs_prop_valid_for_type(int prop, zfs_type_t types)
 {
-	return (zfs_prop_table[prop].pd_attr == prop_readonly);
+	return (zprop_valid_for_type(prop, types));
 }
 
-/*
- * Given a dataset property ID, returns the corresponding name.
- * Assuming the zfs dataset propety ID is valid.
- */
-const char *
-zfs_prop_to_name(zfs_prop_t prop)
+zprop_type_t
+zfs_prop_get_type(zfs_prop_t prop)
 {
-	return (zfs_prop_table[prop].pd_name);
+	return (zfs_prop_table[prop].pd_proptype);
 }
 
 /*
- * Given a pool property ID, returns the corresponding name.
- * Assuming the pool propety ID is valid.
+ * Returns TRUE if the property is readonly.
  */
-const char *
-zpool_prop_to_name(zpool_prop_t prop)
+boolean_t
+zfs_prop_readonly(zfs_prop_t prop)
 {
-	return (zfs_prop_table[prop].pd_name);
+	return (zfs_prop_table[prop].pd_attr == PROP_READONLY ||
+	    zfs_prop_table[prop].pd_attr == PROP_ONETIME);
 }
 
 /*
- * Returns TRUE if the property is inheritable.
+ * Returns TRUE if the property is only allowed to be set once.
  */
-int
-zfs_prop_inheritable(zfs_prop_t prop)
+boolean_t
+zfs_prop_setonce(zfs_prop_t prop)
 {
-	return (zfs_prop_table[prop].pd_attr == prop_inherit);
+	return (zfs_prop_table[prop].pd_attr == PROP_ONETIME);
 }
 
-typedef struct zfs_index {
-	const char *name;
-	uint64_t index;
-} zfs_index_t;
-
-static zfs_index_t checksum_table[] = {
-	{ "on",		ZIO_CHECKSUM_ON },
-	{ "off",	ZIO_CHECKSUM_OFF },
-	{ "fletcher2",	ZIO_CHECKSUM_FLETCHER_2 },
-	{ "fletcher4",	ZIO_CHECKSUM_FLETCHER_4 },
-	{ "sha256",	ZIO_CHECKSUM_SHA256 },
-	{ NULL }
-};
-
-static zfs_index_t compress_table[] = {
-	{ "on",		ZIO_COMPRESS_ON },
-	{ "off",	ZIO_COMPRESS_OFF },
-	{ "lzjb",	ZIO_COMPRESS_LZJB },
-	{ "gzip",	ZIO_COMPRESS_GZIP_6 },	/* the default gzip level */
-	{ "gzip-1",	ZIO_COMPRESS_GZIP_1 },
-	{ "gzip-2",	ZIO_COMPRESS_GZIP_2 },
-	{ "gzip-3",	ZIO_COMPRESS_GZIP_3 },
-	{ "gzip-4",	ZIO_COMPRESS_GZIP_4 },
-	{ "gzip-5",	ZIO_COMPRESS_GZIP_5 },
-	{ "gzip-6",	ZIO_COMPRESS_GZIP_6 },
-	{ "gzip-7",	ZIO_COMPRESS_GZIP_7 },
-	{ "gzip-8",	ZIO_COMPRESS_GZIP_8 },
-	{ "gzip-9",	ZIO_COMPRESS_GZIP_9 },
-	{ NULL }
-};
-
-static zfs_index_t snapdir_table[] = {
-	{ "hidden",	ZFS_SNAPDIR_HIDDEN },
-	{ "visible",	ZFS_SNAPDIR_VISIBLE },
-	{ NULL }
-};
-
-static zfs_index_t acl_mode_table[] = {
-	{ "discard",	ZFS_ACL_DISCARD },
-	{ "groupmask",	ZFS_ACL_GROUPMASK },
-	{ "passthrough", ZFS_ACL_PASSTHROUGH },
-	{ NULL }
-};
-
-static zfs_index_t acl_inherit_table[] = {
-	{ "discard",	ZFS_ACL_DISCARD },
-	{ "noallow",	ZFS_ACL_NOALLOW },
-	{ "secure",	ZFS_ACL_SECURE },
-	{ "passthrough", ZFS_ACL_PASSTHROUGH },
-	{ NULL }
-};
-
-static zfs_index_t copies_table[] = {
-	{ "1",	1 },
-	{ "2",	2 },
-	{ "3",	3 },
-	{ NULL }
-};
-
-static zfs_index_t *
-zfs_prop_index_table(zfs_prop_t prop)
+const char *
+zfs_prop_default_string(zfs_prop_t prop)
 {
-	switch (prop) {
-	case ZFS_PROP_CHECKSUM:
-		return (checksum_table);
-	case ZFS_PROP_COMPRESSION:
-		return (compress_table);
-	case ZFS_PROP_SNAPDIR:
-		return (snapdir_table);
-	case ZFS_PROP_ACLMODE:
-		return (acl_mode_table);
-	case ZFS_PROP_ACLINHERIT:
-		return (acl_inherit_table);
-	case ZFS_PROP_COPIES:
-		return (copies_table);
-	default:
-		return (NULL);
-	}
+	return (zfs_prop_table[prop].pd_strdefault);
 }
 
+uint64_t
+zfs_prop_default_numeric(zfs_prop_t prop)
+{
+	return (zfs_prop_table[prop].pd_numdefault);
+}
 
 /*
- * Tables of index types, plus functions to convert between the user view
- * (strings) and internal representation (uint64_t).
+ * Given a dataset property ID, returns the corresponding name.
+ * Assuming the zfs dataset property ID is valid.
  */
-int
-zfs_prop_string_to_index(zfs_prop_t prop, const char *string, uint64_t *index)
+const char *
+zfs_prop_to_name(zfs_prop_t prop)
 {
-	zfs_index_t *table;
-	int i;
-
-	if ((table = zfs_prop_index_table(prop)) == NULL)
-		return (-1);
-
-	for (i = 0; table[i].name != NULL; i++) {
-		if (strcmp(string, table[i].name) == 0) {
-			*index = table[i].index;
-			return (0);
-		}
-	}
-
-	return (-1);
+	return (zfs_prop_table[prop].pd_name);
 }
 
-int
-zfs_prop_index_to_string(zfs_prop_t prop, uint64_t index, const char **string)
+/*
+ * Returns TRUE if the property is inheritable.
+ */
+boolean_t
+zfs_prop_inheritable(zfs_prop_t prop)
 {
-	zfs_index_t *table;
-	int i;
-
-	if ((table = zfs_prop_index_table(prop)) == NULL)
-		return (-1);
-
-	for (i = 0; table[i].name != NULL; i++) {
-		if (table[i].index == index) {
-			*string = table[i].name;
-			return (0);
-		}
-	}
-
-	return (-1);
+	return (zfs_prop_table[prop].pd_attr == PROP_INHERIT ||
+	    zfs_prop_table[prop].pd_attr == PROP_ONETIME);
 }
 
 #ifndef _KERNEL
@@ -541,22 +457,6 @@ zfs_prop_index_to_string(zfs_prop_t prop, uint64_t index, const char **string)
 const char *
 zfs_prop_values(zfs_prop_t prop)
 {
-	if (zfs_prop_table[prop].pd_types == ZFS_TYPE_POOL)
-		return (NULL);
-
-	return (zfs_prop_table[prop].pd_values);
-}
-
-/*
- * Returns a string describing the set of acceptable values for the given
- * zpool property, or NULL if it cannot be set.
- */
-const char *
-zpool_prop_values(zfs_prop_t prop)
-{
-	if (zfs_prop_table[prop].pd_types != ZFS_TYPE_POOL)
-		return (NULL);
-
 	return (zfs_prop_table[prop].pd_values);
 }
 
@@ -568,8 +468,8 @@ zpool_prop_values(zfs_prop_t prop)
 int
 zfs_prop_is_string(zfs_prop_t prop)
 {
-	return (zfs_prop_table[prop].pd_proptype == prop_type_string ||
-	    zfs_prop_table[prop].pd_proptype == prop_type_index);
+	return (zfs_prop_table[prop].pd_proptype == PROP_TYPE_STRING ||
+	    zfs_prop_table[prop].pd_proptype == PROP_TYPE_INDEX);
 }
 
 /*
@@ -592,66 +492,4 @@ zfs_prop_align_right(zfs_prop_t prop)
 	return (zfs_prop_table[prop].pd_rightalign);
 }
 
-/*
- * Determines the minimum width for the column, and indicates whether it's fixed
- * or not.  Only string columns are non-fixed.
- */
-size_t
-zfs_prop_width(zfs_prop_t prop, boolean_t *fixed)
-{
-	prop_desc_t *pd = &zfs_prop_table[prop];
-	zfs_index_t *idx;
-	size_t ret;
-	int i;
-
-	*fixed = B_TRUE;
-
-	/*
-	 * Start with the width of the column name.
-	 */
-	ret = strlen(pd->pd_colname);
-
-	/*
-	 * For fixed-width values, make sure the width is large enough to hold
-	 * any possible value.
-	 */
-	switch (pd->pd_proptype) {
-	case prop_type_number:
-		/*
-		 * The maximum length of a human-readable number is 5 characters
-		 * ("20.4M", for example).
-		 */
-		if (ret < 5)
-			ret = 5;
-		/*
-		 * 'creation' is handled specially because it's a number
-		 * internally, but displayed as a date string.
-		 */
-		if (prop == ZFS_PROP_CREATION)
-			*fixed = B_FALSE;
-		break;
-	case prop_type_boolean:
-		/*
-		 * The maximum length of a boolean value is 3 characters, for
-		 * "off".
-		 */
-		if (ret < 3)
-			ret = 3;
-		break;
-	case prop_type_index:
-		idx = zfs_prop_index_table(prop);
-		for (i = 0; idx[i].name != NULL; i++) {
-			if (strlen(idx[i].name) > ret)
-				ret = strlen(idx[i].name);
-		}
-		break;
-
-	case prop_type_string:
-		*fixed = B_FALSE;
-		break;
-	}
-
-	return (ret);
-}
-
 #endif
diff --git a/sys/cddl/contrib/opensolaris/common/zfs/zfs_prop.h b/sys/cddl/contrib/opensolaris/common/zfs/zfs_prop.h
index 133e740ce6bc..da5ae43093e5 100644
--- a/sys/cddl/contrib/opensolaris/common/zfs/zfs_prop.h
+++ b/sys/cddl/contrib/opensolaris/common/zfs/zfs_prop.h
@@ -19,7 +19,7 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
@@ -40,14 +40,87 @@ extern "C" {
  * in the kernel, but the string value in userland.
  */
 typedef enum {
-	prop_type_number,	/* numeric value */
-	prop_type_string,	/* string value */
-	prop_type_boolean,	/* boolean value */
-	prop_type_index		/* numeric value indexed by string */
-} zfs_proptype_t;
-
-zfs_proptype_t zfs_prop_get_type(zfs_prop_t);
-size_t zfs_prop_width(zfs_prop_t, boolean_t *);
+	PROP_TYPE_NUMBER,	/* numeric value */
+	PROP_TYPE_STRING,	/* string value */
+	PROP_TYPE_INDEX		/* numeric value indexed by string */
+} zprop_type_t;
+
+typedef enum {
+	PROP_DEFAULT,
+	PROP_READONLY,
+	PROP_INHERIT,
+	/*
+	 * ONETIME properties are a sort of conglomeration of READONLY
+	 * and INHERIT.  They can be set only during object creation,
+	 * after that they are READONLY.  If not explicitly set during
+	 * creation, they can be inherited.
+	 */
+	PROP_ONETIME
+} zprop_attr_t;
+
+typedef struct zfs_index {
+	const char *pi_name;
+	uint64_t pi_value;
+} zprop_index_t;
+
+typedef struct {
+	const char *pd_name;		/* human-readable property name */
+	int pd_propnum;			/* property number */
+	zprop_type_t pd_proptype;	/* string, boolean, index, number */
+	const char *pd_strdefault;	/* default for strings */
+	uint64_t pd_numdefault;		/* for boolean / index / number */
+	zprop_attr_t pd_attr;		/* default, readonly, inherit */
+	int pd_types;			/* bitfield of valid dataset types */
+					/* fs | vol | snap; or pool */
+	const char *pd_values;		/* string telling acceptable values */
+	const char *pd_colname;		/* column header for "zfs list" */
+	boolean_t pd_rightalign;	/* column alignment for "zfs list" */
+	boolean_t pd_visible;		/* do we list this property with the */
+					/* "zfs get" help message */
+	const zprop_index_t *pd_table;	/* for index properties, a table */
+					/* defining the possible values */
+} zprop_desc_t;
+
+/*
+ * zfs dataset property functions
+ */
+void zfs_prop_init(void);
+zprop_type_t zfs_prop_get_type(zfs_prop_t);
+boolean_t zfs_prop_delegatable(zfs_prop_t prop);
+zprop_desc_t *zfs_prop_get_table(void);
+
+/*
+ * zpool property functions
+ */
+void zpool_prop_init(void);
+zprop_type_t zpool_prop_get_type(zpool_prop_t);
+zprop_desc_t *zpool_prop_get_table(void);
+
+/*
+ * Common routines to initialize property tables
+ */
+void register_impl(int, const char *, zprop_type_t, uint64_t,
+    const char *, zprop_attr_t, int, const char *, const char *,
+    boolean_t, boolean_t, const zprop_index_t *);
+void register_string(int, const char *, const char *, zprop_attr_t attr,
+    int, const char *, const char *);
+void register_number(int, const char *, uint64_t, zprop_attr_t, int,
+    const char *, const char *);
+void register_index(int, const char *, uint64_t, zprop_attr_t, int,
+    const char *, const char *, const zprop_index_t *);
+void register_hidden(int, const char *, zprop_type_t, zprop_attr_t,
+    int, const char *);
+
+/*
+ * Common routines for zfs and zpool property management
+ */
+int zprop_iter_common(zprop_func, void *, boolean_t, boolean_t, zfs_type_t);
+int zprop_name_to_prop(const char *, zfs_type_t);
+int zprop_string_to_index(int, const char *, uint64_t *, zfs_type_t);
+int zprop_index_to_string(int, uint64_t, const char **, zfs_type_t);
+const char *zprop_values(int, zfs_type_t);
+size_t zprop_width(int, boolean_t *, zfs_type_t);
+boolean_t zprop_valid_for_type(int, zfs_type_t);
 
 #ifdef	__cplusplus
 }
diff --git a/sys/cddl/contrib/opensolaris/common/zfs/zpool_prop.c b/sys/cddl/contrib/opensolaris/common/zfs/zpool_prop.c
new file mode 100644
index 000000000000..f5efe18d248b
--- /dev/null
+++ b/sys/cddl/contrib/opensolaris/common/zfs/zpool_prop.c
@@ -0,0 +1,186 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License (the "License").
+ * You may not use this file except in compliance with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or http://www.opensolaris.org/os/licensing.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+/*
+ * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+ * Use is subject to license terms.
+ */
+
+#include <sys/zio.h>
+#include <sys/spa.h>
+#include <sys/zfs_acl.h>
+#include <sys/zfs_ioctl.h>
+#include <sys/fs/zfs.h>
+
+#include "zfs_prop.h"
+
+#if defined(_KERNEL)
+#include <sys/systm.h>
+#else
+#include <stdlib.h>
+#include <string.h>
+#include <ctype.h>
+#endif
+
+static zprop_desc_t zpool_prop_table[ZPOOL_NUM_PROPS];
+
+zprop_desc_t *
+zpool_prop_get_table(void)
+{
+	return (zpool_prop_table);
+}
+
+void
+zpool_prop_init(void)
+{
+	static zprop_index_t boolean_table[] = {
+		{ "off",	0},
+		{ "on",		1},
+		{ NULL }
+	};
+
+	static zprop_index_t failuremode_table[] = {
+		{ "wait",	ZIO_FAILURE_MODE_WAIT },
+		{ "continue",	ZIO_FAILURE_MODE_CONTINUE },
+		{ "panic",	ZIO_FAILURE_MODE_PANIC },
+		{ NULL }
+	};
+
+	/* string properties */
+	register_string(ZPOOL_PROP_ALTROOT, "altroot", NULL, PROP_DEFAULT,
+	    ZFS_TYPE_POOL, "<path>", "ALTROOT");
+	register_string(ZPOOL_PROP_BOOTFS, "bootfs", NULL, PROP_DEFAULT,
+	    ZFS_TYPE_POOL, "<filesystem>", "BOOTFS");
+	register_string(ZPOOL_PROP_CACHEFILE, "cachefile", NULL, PROP_DEFAULT,
+	    ZFS_TYPE_POOL, "<file> | none", "CACHEFILE");
+
+	/* readonly number properties */
+	register_number(ZPOOL_PROP_SIZE, "size", 0, PROP_READONLY,
+	    ZFS_TYPE_POOL, "<size>", "SIZE");
+	register_number(ZPOOL_PROP_USED, "used", 0, PROP_READONLY,
+	    ZFS_TYPE_POOL, "<size>", "USED");
+	register_number(ZPOOL_PROP_AVAILABLE, "available", 0, PROP_READONLY,
+	    ZFS_TYPE_POOL, "<size>", "AVAIL");
+	register_number(ZPOOL_PROP_CAPACITY, "capacity", 0, PROP_READONLY,
+	    ZFS_TYPE_POOL, "<size>", "CAP");
+	register_number(ZPOOL_PROP_GUID, "guid", 0, PROP_READONLY,
+	    ZFS_TYPE_POOL, "<guid>", "GUID");
+	register_number(ZPOOL_PROP_HEALTH, "health", 0, PROP_READONLY,
+	    ZFS_TYPE_POOL, "<state>", "HEALTH");
+
+	/* default number properties */
+	register_number(ZPOOL_PROP_VERSION, "version", SPA_VERSION,
+	    PROP_DEFAULT, ZFS_TYPE_POOL, "<version>", "VERSION");
+
+	/* default index (boolean) properties */
+	register_index(ZPOOL_PROP_DELEGATION, "delegation", 1, PROP_DEFAULT,
+	    ZFS_TYPE_POOL, "on | off", "DELEGATION", boolean_table);
+	register_index(ZPOOL_PROP_AUTOREPLACE, "autoreplace", 0, PROP_DEFAULT,
+	    ZFS_TYPE_POOL, "on | off", "REPLACE", boolean_table);
+	register_index(ZPOOL_PROP_LISTSNAPS, "listsnapshots", 0, PROP_DEFAULT,
+	    ZFS_TYPE_POOL, "on | off", "LISTSNAPS", boolean_table);
+
+	/* default index properties */
+	register_index(ZPOOL_PROP_FAILUREMODE, "failmode",
+	    ZIO_FAILURE_MODE_WAIT, PROP_DEFAULT, ZFS_TYPE_POOL,
+	    "wait | continue | panic", "FAILMODE", failuremode_table);
+
+	/* hidden properties */
+	register_hidden(ZPOOL_PROP_NAME, "name", PROP_TYPE_STRING,
+	    PROP_READONLY, ZFS_TYPE_POOL, "NAME");
+}
+
+/*
+ * Given a property name and its type, returns the corresponding property ID.
+ */
+zpool_prop_t
+zpool_name_to_prop(const char *propname)
+{
+	return (zprop_name_to_prop(propname, ZFS_TYPE_POOL));
+}
+
+/*
+ * Given a pool property ID, returns the corresponding name.
+ * Assuming the pool propety ID is valid.
+ */
+const char *
+zpool_prop_to_name(zpool_prop_t prop)
+{
+	return (zpool_prop_table[prop].pd_name);
+}
+
+zprop_type_t
+zpool_prop_get_type(zpool_prop_t prop)
+{
+	return (zpool_prop_table[prop].pd_proptype);
+}
+
+boolean_t
+zpool_prop_readonly(zpool_prop_t prop)
+{
+	return (zpool_prop_table[prop].pd_attr == PROP_READONLY);
+}
+
+const char *
+zpool_prop_default_string(zpool_prop_t prop)
+{
+	return (zpool_prop_table[prop].pd_strdefault);
+}
+
+uint64_t
+zpool_prop_default_numeric(zpool_prop_t prop)
+{
+	return (zpool_prop_table[prop].pd_numdefault);
+}
+
+int
+zpool_prop_string_to_index(zpool_prop_t prop, const char *string,
+    uint64_t *index)
+{
+	return (zprop_string_to_index(prop, string, index, ZFS_TYPE_POOL));
+}
+
+int
+zpool_prop_index_to_string(zpool_prop_t prop, uint64_t index,
+    const char **string)
+{
+	return (zprop_index_to_string(prop, index, string, ZFS_TYPE_POOL));
+}
+
+#ifndef _KERNEL
+
+const char *
+zpool_prop_values(zpool_prop_t prop)
+{
+	return (zpool_prop_table[prop].pd_values);
+}
+
+const char *
+zpool_prop_column_name(zpool_prop_t prop)
+{
+	return (zpool_prop_table[prop].pd_colname);
+}
+
+boolean_t
+zpool_prop_align_right(zpool_prop_t prop)
+{
+	return (zpool_prop_table[prop].pd_rightalign);
+}
+#endif
diff --git a/sys/cddl/contrib/opensolaris/common/zfs/zprop_common.c b/sys/cddl/contrib/opensolaris/common/zfs/zprop_common.c
new file mode 100644
index 000000000000..87619e1cbf07
--- /dev/null
+++ b/sys/cddl/contrib/opensolaris/common/zfs/zprop_common.c
@@ -0,0 +1,406 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License (the "License").
+ * You may not use this file except in compliance with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or http://www.opensolaris.org/os/licensing.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+/*
+ * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+ * Use is subject to license terms.
+ */
+
+#pragma ident	"%Z%%M%	%I%	%E% SMI"
+
+/*
+ * Common routines used by zfs and zpool property management.
+ */
+
+#include <sys/zio.h>
+#include <sys/spa.h>
+#include <sys/zfs_acl.h>
+#include <sys/zfs_ioctl.h>
+#include <sys/zfs_znode.h>
+#include <sys/fs/zfs.h>
+
+#include "zfs_prop.h"
+#include "zfs_deleg.h"
+
+#if defined(_KERNEL)
+#include <sys/systm.h>
+#include <sys/libkern.h>
+#else
+#include <stdlib.h>
+#include <string.h>
+#include <ctype.h>
+#endif
+
+static zprop_desc_t *
+zprop_get_proptable(zfs_type_t type)
+{
+	if (type == ZFS_TYPE_POOL)
+		return (zpool_prop_get_table());
+	else
+		return (zfs_prop_get_table());
+}
+
+static int
+zprop_get_numprops(zfs_type_t type)
+{
+	if (type == ZFS_TYPE_POOL)
+		return (ZPOOL_NUM_PROPS);
+	else
+		return (ZFS_NUM_PROPS);
+}
+
+void
+register_impl(int prop, const char *name, zprop_type_t type,
+    uint64_t numdefault, const char *strdefault, zprop_attr_t attr,
+    int objset_types, const char *values, const char *colname,
+    boolean_t rightalign, boolean_t visible, const zprop_index_t *idx_tbl)
+{
+	zprop_desc_t *prop_tbl = zprop_get_proptable(objset_types);
+	zprop_desc_t *pd;
+
+	pd = &prop_tbl[prop];
+
+	ASSERT(pd->pd_name == NULL || pd->pd_name == name);
+
+	pd->pd_name = name;
+	pd->pd_propnum = prop;
+	pd->pd_proptype = type;
+	pd->pd_numdefault = numdefault;
+	pd->pd_strdefault = strdefault;
+	pd->pd_attr = attr;
+	pd->pd_types = objset_types;
+	pd->pd_values = values;
+	pd->pd_colname = colname;
+	pd->pd_rightalign = rightalign;
+	pd->pd_visible = visible;
+	pd->pd_table = idx_tbl;
+}
+
+void
+register_string(int prop, const char *name, const char *def,
+    zprop_attr_t attr, int objset_types, const char *values,
+    const char *colname)
+{
+	register_impl(prop, name, PROP_TYPE_STRING, 0, def, attr,
+	    objset_types, values, colname, B_FALSE, B_TRUE, NULL);
+
+}
+
+void
+register_number(int prop, const char *name, uint64_t def, zprop_attr_t attr,
+    int objset_types, const char *values, const char *colname)
+{
+	register_impl(prop, name, PROP_TYPE_NUMBER, def, NULL, attr,
+	    objset_types, values, colname, B_TRUE, B_TRUE, NULL);
+}
+
+void
+register_index(int prop, const char *name, uint64_t def, zprop_attr_t attr,
+    int objset_types, const char *values, const char *colname,
+    const zprop_index_t *idx_tbl)
+{
+	register_impl(prop, name, PROP_TYPE_INDEX, def, NULL, attr,
+	    objset_types, values, colname, B_TRUE, B_TRUE, idx_tbl);
+}
+
+void
+register_hidden(int prop, const char *name, zprop_type_t type,
+    zprop_attr_t attr, int objset_types, const char *colname)
+{
+	register_impl(prop, name, type, 0, NULL, attr,
+	    objset_types, NULL, colname, B_FALSE, B_FALSE, NULL);
+}
+
+
+/*
+ * A comparison function we can use to order indexes into property tables.
+ */
+static int
+zprop_compare(const void *arg1, const void *arg2)
+{
+	const zprop_desc_t *p1 = *((zprop_desc_t **)arg1);
+	const zprop_desc_t *p2 = *((zprop_desc_t **)arg2);
+	boolean_t p1ro, p2ro;
+
+	p1ro = (p1->pd_attr == PROP_READONLY);
+	p2ro = (p2->pd_attr == PROP_READONLY);
+
+	if (p1ro == p2ro)
+		return (strcmp(p1->pd_name, p2->pd_name));
+
+	return (p1ro ? -1 : 1);
+}
+
+/*
+ * Iterate over all properties in the given property table, calling back
+ * into the specified function for each property. We will continue to
+ * iterate until we either reach the end or the callback function returns
+ * something other than ZPROP_CONT.
+ */
+int
+zprop_iter_common(zprop_func func, void *cb, boolean_t show_all,
+    boolean_t ordered, zfs_type_t type)
+{
+	int i, j, num_props, size, prop;
+	zprop_desc_t *prop_tbl;
+	zprop_desc_t **order;
+
+	prop_tbl = zprop_get_proptable(type);
+	num_props = zprop_get_numprops(type);
+	size = num_props * sizeof (zprop_desc_t *);
+
+#if defined(_KERNEL)
+	order = kmem_alloc(size, KM_SLEEP);
+#else
+	if ((order = malloc(size)) == NULL)
+		return (ZPROP_CONT);
+#endif
+
+	for (j = 0; j < num_props; j++)
+		order[j] = &prop_tbl[j];
+
+	if (ordered) {
+		qsort((void *)order, num_props, sizeof (zprop_desc_t *),
+		    zprop_compare);
+	}
+
+	prop = ZPROP_CONT;
+	for (i = 0; i < num_props; i++) {
+		if ((order[i]->pd_visible || show_all) &&
+		    (func(order[i]->pd_propnum, cb) != ZPROP_CONT)) {
+			prop = order[i]->pd_propnum;
+			break;
+		}
+	}
+
+#if defined(_KERNEL)
+	kmem_free(order, size);
+#else
+	free(order);
+#endif
+	return (prop);
+}
+
+static boolean_t
+propname_match(const char *p, size_t len, zprop_desc_t *prop_entry)
+{
+	const char *propname = prop_entry->pd_name;
+#ifndef _KERNEL
+	const char *colname = prop_entry->pd_colname;
+	int c;
+
+	if (colname == NULL)
+		return (B_FALSE);
+#endif
+
+	if (len == strlen(propname) &&
+	    strncmp(p, propname, len) == 0)
+		return (B_TRUE);
+
+#ifndef _KERNEL
+	if (len != strlen(colname))
+		return (B_FALSE);
+
+	for (c = 0; c < len; c++)
+		if (p[c] != tolower(colname[c]))
+			break;
+
+	return (colname[c] == '\0');
+#else
+	return (B_FALSE);
+#endif
+}
+
+typedef struct name_to_prop_cb {
+	const char *propname;
+	zprop_desc_t *prop_tbl;
+} name_to_prop_cb_t;
+
+static int
+zprop_name_to_prop_cb(int prop, void *cb_data)
+{
+	name_to_prop_cb_t *data = cb_data;
+
+	if (propname_match(data->propname, strlen(data->propname),
+	    &data->prop_tbl[prop]))
+		return (prop);
+
+	return (ZPROP_CONT);
+}
+
+int
+zprop_name_to_prop(const char *propname, zfs_type_t type)
+{
+	int prop;
+	name_to_prop_cb_t cb_data;
+
+	cb_data.propname = propname;
+	cb_data.prop_tbl = zprop_get_proptable(type);
+
+	prop = zprop_iter_common(zprop_name_to_prop_cb, &cb_data,
+	    B_TRUE, B_FALSE, type);
+
+	return (prop == ZPROP_CONT ? ZPROP_INVAL : prop);
+}
+
+int
+zprop_string_to_index(int prop, const char *string, uint64_t *index,
+    zfs_type_t type)
+{
+	zprop_desc_t *prop_tbl;
+	const zprop_index_t *idx_tbl;
+	int i;
+
+	if (prop == ZPROP_INVAL || prop == ZPROP_CONT)
+		return (-1);
+
+	ASSERT(prop < zprop_get_numprops(type));
+	prop_tbl = zprop_get_proptable(type);
+	if ((idx_tbl = prop_tbl[prop].pd_table) == NULL)
+		return (-1);
+
+	for (i = 0; idx_tbl[i].pi_name != NULL; i++) {
+		if (strcmp(string, idx_tbl[i].pi_name) == 0) {
+			*index = idx_tbl[i].pi_value;
+			return (0);
+		}
+	}
+
+	return (-1);
+}
+
+int
+zprop_index_to_string(int prop, uint64_t index, const char **string,
+    zfs_type_t type)
+{
+	zprop_desc_t *prop_tbl;
+	const zprop_index_t *idx_tbl;
+	int i;
+
+	if (prop == ZPROP_INVAL || prop == ZPROP_CONT)
+		return (-1);
+
+	ASSERT(prop < zprop_get_numprops(type));
+	prop_tbl = zprop_get_proptable(type);
+	if ((idx_tbl = prop_tbl[prop].pd_table) == NULL)
+		return (-1);
+
+	for (i = 0; idx_tbl[i].pi_name != NULL; i++) {
+		if (idx_tbl[i].pi_value == index) {
+			*string = idx_tbl[i].pi_name;
+			return (0);
+		}
+	}
+
+	return (-1);
+}
+
+const char *
+zprop_values(int prop, zfs_type_t type)
+{
+	zprop_desc_t *prop_tbl;
+
+	ASSERT(prop != ZPROP_INVAL && prop != ZPROP_CONT);
+	ASSERT(prop < zprop_get_numprops(type));
+
+	prop_tbl = zprop_get_proptable(type);
+
+	return (prop_tbl[prop].pd_values);
+}
+
+/*
+ * Returns TRUE if the property applies to any of the given dataset types.
+ */
+boolean_t
+zprop_valid_for_type(int prop, zfs_type_t type)
+{
+	zprop_desc_t *prop_tbl;
+
+	if (prop == ZPROP_INVAL || prop == ZPROP_CONT)
+		return (B_FALSE);
+
+	ASSERT(prop < zprop_get_numprops(type));
+	prop_tbl = zprop_get_proptable(type);
+	return ((prop_tbl[prop].pd_types & type) != 0);
+}
+
+#ifndef _KERNEL
+
+/*
+ * Determines the minimum width for the column, and indicates whether it's fixed
+ * or not.  Only string columns are non-fixed.
+ */
+size_t
+zprop_width(int prop, boolean_t *fixed, zfs_type_t type)
+{
+	zprop_desc_t *prop_tbl, *pd;
+	const zprop_index_t *idx;
+	size_t ret;
+	int i;
+
+	ASSERT(prop != ZPROP_INVAL && prop != ZPROP_CONT);
+	ASSERT(prop < zprop_get_numprops(type));
+
+	prop_tbl = zprop_get_proptable(type);
+	pd = &prop_tbl[prop];
+
+	*fixed = B_TRUE;
+
+	/*
+	 * Start with the width of the column name.
+	 */
+	ret = strlen(pd->pd_colname);
+
+	/*
+	 * For fixed-width values, make sure the width is large enough to hold
+	 * any possible value.
+	 */
+	switch (pd->pd_proptype) {
+	case PROP_TYPE_NUMBER:
+		/*
+		 * The maximum length of a human-readable number is 5 characters
+		 * ("20.4M", for example).
+		 */
+		if (ret < 5)
+			ret = 5;
+		/*
+		 * 'creation' is handled specially because it's a number
+		 * internally, but displayed as a date string.
+		 */
+		if (prop == ZFS_PROP_CREATION)
+			*fixed = B_FALSE;
+		break;
+	case PROP_TYPE_INDEX:
+		idx = prop_tbl[prop].pd_table;
+		for (i = 0; idx[i].pi_name != NULL; i++) {
+			if (strlen(idx[i].pi_name) > ret)
+				ret = strlen(idx[i].pi_name);
+		}
+		break;
+
+	case PROP_TYPE_STRING:
+		*fixed = B_FALSE;
+		break;
+	}
+
+	return (ret);
+}
+
+#endif
diff --git a/sys/cddl/contrib/opensolaris/uts/common/Makefile.files b/sys/cddl/contrib/opensolaris/uts/common/Makefile.files
index 1800e792fa1e..cf49c78a5b0e 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/Makefile.files
+++ b/sys/cddl/contrib/opensolaris/uts/common/Makefile.files
@@ -20,11 +20,9 @@
 #
 
 #
-# Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
+# Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
 # Use is subject to license terms.
 #
-# ident	"%Z%%M%	%I%	%E% SMI"
-#
 # This Makefile defines all file modules for the directory uts/common
 # and its children. These are the source files which may be considered
 # common to all SunOS systems.
@@ -46,7 +44,9 @@ ZFS_COMMON_OBJS +=		\
 	dsl_pool.o		\
 	dsl_synctask.o		\
 	dmu_zfetch.o		\
+	dsl_deleg.o		\
 	dsl_prop.o		\
+	dsl_scrub.o		\
 	fletcher.o		\
 	gzip.o			\
 	lzjb.o			\
@@ -64,6 +64,7 @@ ZFS_COMMON_OBJS +=		\
 	unique.o		\
 	vdev.o			\
 	vdev_cache.o		\
+	vdev_file.o		\
 	vdev_label.o		\
 	vdev_mirror.o		\
 	vdev_missing.o		\
@@ -75,6 +76,7 @@ ZFS_COMMON_OBJS +=		\
 	zap_micro.o		\
 	zfs_byteswap.o		\
 	zfs_fm.o		\
+	zfs_fuid.o		\
 	zfs_znode.o		\
 	zil.o			\
 	zio.o			\
@@ -84,7 +86,11 @@ ZFS_COMMON_OBJS +=		\
 
 ZFS_SHARED_OBJS +=		\
 	zfs_namecheck.o		\
-	zfs_prop.o
+	zfs_deleg.o		\
+	zfs_prop.o		\
+	zfs_comutil.o		\
+	zpool_prop.o		\
+	zprop_common.o
 
 ZFS_OBJS +=			\
 	$(ZFS_COMMON_OBJS)	\
@@ -96,6 +102,7 @@ ZFS_OBJS +=			\
 	zfs_log.o		\
 	zfs_replay.o		\
 	zfs_rlock.o		\
+	rrwlock.o		\
 	zfs_vfsops.o		\
 	zfs_vnops.o		\
 	zvol.o
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/gfs.c b/sys/cddl/contrib/opensolaris/uts/common/fs/gfs.c
index dd2aa82304ab..d9eb88a40202 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/gfs.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/gfs.c
@@ -20,7 +20,7 @@
  */
 /* Portions Copyright 2007 Shivakumar GN */
 /*
- * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
@@ -35,6 +35,7 @@
 #include <sys/mutex.h>
 #include <sys/sysmacros.h>
 #include <sys/systm.h>
+#include <sys/sunddi.h>
 #include <sys/uio.h>
 #include <sys/vfs.h>
 #include <sys/vnode.h>
@@ -60,7 +61,7 @@
  *
  *    These routines are designed to play a support role for existing
  *    pseudo-filesystems (such as procfs).  They simplify common tasks,
- *    without enforcing the filesystem to hand over management to GFS.  The
+ *    without forcing the filesystem to hand over management to GFS.  The
  *    routines covered are:
  *
  *	gfs_readdir_init()
@@ -116,6 +117,42 @@
  */
 
 /*
+ * gfs_get_parent_ino: used to obtain a parent inode number and the
+ * inode number of the given vnode in preparation for calling gfs_readdir_init.
+ */
+int
+gfs_get_parent_ino(vnode_t *dvp, cred_t *cr, caller_context_t *ct,
+    ino64_t *pino, ino64_t *ino)
+{
+	vnode_t *parent;
+	gfs_dir_t *dp = dvp->v_data;
+	int error;
+
+	*ino = dp->gfsd_file.gfs_ino;
+	parent = dp->gfsd_file.gfs_parent;
+
+	if (parent == NULL) {
+		*pino = *ino;		/* root of filesystem */
+	} else if (dvp->v_flag & V_XATTRDIR) {
+#ifdef TODO
+		vattr_t va;
+
+		va.va_mask = AT_NODEID;
+		error = VOP_GETATTR(parent, &va, 0, cr, ct);
+		if (error)
+			return (error);
+		*pino = va.va_nodeid;
+#else
+		panic("%s:%u: not implemented", __func__, __LINE__);
+#endif
+	} else {
+		*pino = ((gfs_file_t *)(parent->v_data))->gfs_ino;
+	}
+
+	return (0);
+}
+
+/*
  * gfs_readdir_init: initiate a generic readdir
  *   st		- a pointer to an uninitialized gfs_readdir_state_t structure
  *   name_max	- the directory's maximum file name length
@@ -123,6 +160,7 @@
  *   uiop	- the uiop passed to readdir
  *   parent	- the parent directory's inode
  *   self	- this directory's inode
+ *   flags	- flags from VOP_READDIR
  *
  * Returns 0 or a non-zero errno.
  *
@@ -153,8 +191,10 @@
  */
 int
 gfs_readdir_init(gfs_readdir_state_t *st, int name_max, int ureclen,
-    uio_t *uiop, ino64_t parent, ino64_t self)
+    uio_t *uiop, ino64_t parent, ino64_t self, int flags)
 {
+	size_t dirent_size;
+
 	if (uiop->uio_loffset < 0 || uiop->uio_resid <= 0 ||
 	    (uiop->uio_loffset % ureclen) != 0)
 		return (EINVAL);
@@ -162,9 +202,14 @@ gfs_readdir_init(gfs_readdir_state_t *st, int name_max, int ureclen,
 	st->grd_ureclen = ureclen;
 	st->grd_oresid = uiop->uio_resid;
 	st->grd_namlen = name_max;
-	st->grd_dirent = kmem_zalloc(DIRENT64_RECLEN(st->grd_namlen), KM_SLEEP);
+	if (flags & V_RDDIR_ENTFLAGS)
+		dirent_size = EDIRENT_RECLEN(st->grd_namlen);
+	else
+		dirent_size = DIRENT64_RECLEN(st->grd_namlen);
+	st->grd_dirent = kmem_zalloc(dirent_size, KM_SLEEP);
 	st->grd_parent = parent;
 	st->grd_self = self;
+	st->grd_flags = flags;
 
 	return (0);
 }
@@ -172,8 +217,8 @@ gfs_readdir_init(gfs_readdir_state_t *st, int name_max, int ureclen,
 /*
  * gfs_readdir_emit_int: internal routine to emit directory entry
  *
- *   st		- the current readdir state, which must have d_ino and d_name
- *                set
+ *   st		- the current readdir state, which must have d_ino/ed_ino
+ *		  and d_name/ed_name set
  *   uiop	- caller-supplied uio pointer
  *   next	- the offset of the next entry
  */
@@ -182,9 +227,18 @@ gfs_readdir_emit_int(gfs_readdir_state_t *st, uio_t *uiop, offset_t next,
     int *ncookies, u_long **cookies)
 {
 	int reclen, namlen;
+	dirent64_t *dp;
+	edirent_t *edp;
 
-	namlen = strlen(st->grd_dirent->d_name);
-	reclen = DIRENT64_RECLEN(namlen);
+	if (st->grd_flags & V_RDDIR_ENTFLAGS) {
+		edp = st->grd_dirent;
+		namlen = strlen(edp->ed_name);
+		reclen = EDIRENT_RECLEN(namlen);
+	} else {
+		dp = st->grd_dirent;
+		namlen = strlen(dp->d_name);
+		reclen = DIRENT64_RECLEN(namlen);
+	}
 
 	if (reclen > uiop->uio_resid) {
 		/*
@@ -195,10 +249,15 @@ gfs_readdir_emit_int(gfs_readdir_state_t *st, uio_t *uiop, offset_t next,
 		return (-1);
 	}
 
-	/* XXX: This can change in the future. */
-	st->grd_dirent->d_type = DT_DIR;
-	st->grd_dirent->d_reclen = (ushort_t)reclen;
-	st->grd_dirent->d_namlen = namlen;
+	if (st->grd_flags & V_RDDIR_ENTFLAGS) {
+		edp->ed_off = next;
+		edp->ed_reclen = (ushort_t)reclen;
+	} else {
+		/* XXX: This can change in the future. */
+		dp->d_reclen = (ushort_t)reclen;
+		dp->d_type = DT_DIR;
+		dp->d_namlen = namlen;
+	}
 
 	if (uiomove((caddr_t)st->grd_dirent, reclen, UIO_READ, uiop))
 		return (EFAULT);
@@ -219,6 +278,7 @@ gfs_readdir_emit_int(gfs_readdir_state_t *st, uio_t *uiop, offset_t next,
  *   voff       - the virtual offset (obtained from gfs_readdir_pred)
  *   ino        - the entry's inode
  *   name       - the entry's name
+ *   eflags	- value for ed_eflags (if processing edirent_t)
  *
  * Returns a 0 on success, a non-zero errno on failure, or -1 if the
  * readdir loop should terminate.  A non-zero result (either errno or
@@ -227,12 +287,22 @@ gfs_readdir_emit_int(gfs_readdir_state_t *st, uio_t *uiop, offset_t next,
  */
 int
 gfs_readdir_emit(gfs_readdir_state_t *st, uio_t *uiop, offset_t voff,
-    ino64_t ino, const char *name, int *ncookies, u_long **cookies)
+    ino64_t ino, const char *name, int eflags, int *ncookies, u_long **cookies)
 {
 	offset_t off = (voff + 2) * st->grd_ureclen;
 
-	st->grd_dirent->d_ino = ino;
-	(void) strncpy(st->grd_dirent->d_name, name, st->grd_namlen);
+	if (st->grd_flags & V_RDDIR_ENTFLAGS) {
+		edirent_t *edp = st->grd_dirent;
+
+		edp->ed_ino = ino;
+		(void) strncpy(edp->ed_name, name, st->grd_namlen);
+		edp->ed_eflags = eflags;
+	} else {
+		dirent64_t *dp = st->grd_dirent;
+
+		dp->d_ino = ino;
+		(void) strncpy(dp->d_name, name, st->grd_namlen);
+	}
 
 	/*
 	 * Inter-entry offsets are invalid, so we assume a record size of
@@ -266,11 +336,11 @@ top:
 	voff = off - 2;
 	if (off == 0) {
 		if ((error = gfs_readdir_emit(st, uiop, voff, st->grd_self,
-		    ".", ncookies, cookies)) == 0)
+		    ".", 0, ncookies, cookies)) == 0)
 			goto top;
 	} else if (off == 1) {
 		if ((error = gfs_readdir_emit(st, uiop, voff, st->grd_parent,
-		    "..", ncookies, cookies)) == 0)
+		    "..", 0, ncookies, cookies)) == 0)
 			goto top;
 	} else {
 		*voffp = voff;
@@ -292,7 +362,13 @@ top:
 int
 gfs_readdir_fini(gfs_readdir_state_t *st, int error, int *eofp, int eof)
 {
-	kmem_free(st->grd_dirent, DIRENT64_RECLEN(st->grd_namlen));
+	size_t dirent_size;
+
+	if (st->grd_flags & V_RDDIR_ENTFLAGS)
+		dirent_size = EDIRENT_RECLEN(st->grd_namlen);
+	else
+		dirent_size = DIRENT64_RECLEN(st->grd_namlen);
+	kmem_free(st->grd_dirent, dirent_size);
 	if (error > 0)
 		return (error);
 	if (eofp)
@@ -485,7 +561,7 @@ gfs_file_inactive(vnode_t *vp)
 	gfs_dir_t *dp = NULL;
 	void *data;
 
-	if (fp->gfs_parent == NULL)
+	if (fp->gfs_parent == NULL || (vp->v_flag & V_XATTRDIR))
 		goto found;
 
 	dp = fp->gfs_parent->v_data;
@@ -511,6 +587,8 @@ gfs_file_inactive(vnode_t *vp)
 	ge = NULL;
 
 found:
+	if (vp->v_flag & V_XATTRDIR)
+		VI_LOCK(fp->gfs_parent);
 	VI_LOCK(vp);
 	ASSERT(vp->v_count < 2);
 	/*
@@ -535,7 +613,8 @@ found:
 	 * Free vnode and release parent
 	 */
 	if (fp->gfs_parent) {
-		gfs_dir_unlock(dp);
+		if (dp)
+			gfs_dir_unlock(dp);
 		VI_LOCK(fp->gfs_parent);
 		fp->gfs_parent->v_usecount--;
 		VI_UNLOCK(fp->gfs_parent);
@@ -543,6 +622,8 @@ found:
 		ASSERT(vp->v_vfsp != NULL);
 		VFS_RELE(vp->v_vfsp);
 	}
+	if (vp->v_flag & V_XATTRDIR)
+		VI_UNLOCK(fp->gfs_parent);
 
 	return (data);
 }
@@ -570,55 +651,119 @@ gfs_dir_inactive(vnode_t *vp)
 }
 
 /*
- * gfs_dir_lookup()
+ * gfs_dir_lookup_dynamic()
  *
- * Looks up the given name in the directory and returns the corresponding vnode,
- * if found.
+ * This routine looks up the provided name amongst the dynamic entries
+ * in the gfs directory and returns the corresponding vnode, if found.
  *
- * First, we search statically defined entries, if any.  If a match is found,
- * and GFS_CACHE_VNODE is set and the vnode exists, we simply return the
- * existing vnode.  Otherwise, we call the static entry's callback routine,
- * caching the result if necessary.
+ * The gfs directory is expected to be locked by the caller prior to
+ * calling this function.  The directory will be unlocked during the
+ * execution of this function, but will be locked upon return from the
+ * function.  This function returns 0 on success, non-zero on error.
  *
- * If no static entry is found, we invoke the lookup callback, if any.  The
- * arguments to this callback are:
+ * The dynamic lookups are performed by invoking the lookup
+ * callback, which is passed to this function as the first argument.
+ * The arguments to the callback are:
  *
- *	int gfs_lookup_cb(vnode_t *pvp, const char *nm, vnode_t **vpp);
+ * int gfs_lookup_cb(vnode_t *pvp, const char *nm, vnode_t **vpp, cred_t *cr,
+ *     int flags, int *deflgs, pathname_t *rpnp);
  *
  *	pvp	- parent vnode
  *	nm	- name of entry
  *	vpp	- pointer to resulting vnode
+ *	cr	- pointer to cred
+ *	flags	- flags value from lookup request
+ *		ignored here; currently only used to request
+ *		insensitive lookups
+ *	direntflgs - output parameter, directory entry flags
+ *		ignored here; currently only used to indicate a lookup
+ *		has more than one possible match when case is not considered
+ *	realpnp	- output parameter, real pathname
+ *		ignored here; when lookup was performed case-insensitively,
+ *		this field contains the "real" name of the file.
  *
  * 	Returns 0 on success, non-zero on error.
  */
-int
-gfs_dir_lookup(vnode_t *dvp, const char *nm, vnode_t **vpp)
+static int
+gfs_dir_lookup_dynamic(gfs_lookup_cb callback, gfs_dir_t *dp,
+    const char *nm, vnode_t *dvp, vnode_t **vpp, cred_t *cr, int flags,
+    int *direntflags, pathname_t *realpnp)
 {
-	int i;
-	gfs_dirent_t *ge;
-	vnode_t *vp;
-	gfs_dir_t *dp = dvp->v_data;
-	int ret = 0;
-
-	ASSERT(dvp->v_type == VDIR);
+	gfs_file_t *fp;
+	ino64_t ino;
+	int ret;
 
-	if (gfs_lookup_dot(vpp, dvp, dp->gfsd_file.gfs_parent, nm) == 0)
-		return (0);
+	ASSERT(GFS_DIR_LOCKED(dp));
 
+	/*
+	 * Drop the directory lock, as the lookup routine
+	 * will need to allocate memory, or otherwise deadlock on this
+	 * directory.
+	 */
+	gfs_dir_unlock(dp);
+	ret = callback(dvp, nm, vpp, &ino, cr, flags, direntflags, realpnp);
 	gfs_dir_lock(dp);
 
 	/*
+	 * The callback for extended attributes returns a vnode
+	 * with v_data from an underlying fs.
+	 */
+	if (ret == 0 && !IS_XATTRDIR(dvp)) {
+		fp = (gfs_file_t *)((*vpp)->v_data);
+		fp->gfs_index = -1;
+		fp->gfs_ino = ino;
+	}
+
+	return (ret);
+}
+
+/*
+ * gfs_dir_lookup_static()
+ *
+ * This routine looks up the provided name amongst the static entries
+ * in the gfs directory and returns the corresponding vnode, if found.
+ * The first argument to the function is a pointer to the comparison
+ * function this function should use to decide if names are a match.
+ *
+ * If a match is found, and GFS_CACHE_VNODE is set and the vnode
+ * exists, we simply return the existing vnode.  Otherwise, we call
+ * the static entry's callback routine, caching the result if
+ * necessary.  If the idx pointer argument is non-NULL, we use it to
+ * return the index of the matching static entry.
+ *
+ * The gfs directory is expected to be locked by the caller prior to calling
+ * this function.  The directory may be unlocked during the execution of
+ * this function, but will be locked upon return from the function.
+ *
+ * This function returns 0 if a match is found, ENOENT if not.
+ */
+static int
+gfs_dir_lookup_static(int (*compare)(const char *, const char *),
+    gfs_dir_t *dp, const char *nm, vnode_t *dvp, int *idx,
+    vnode_t **vpp, pathname_t *rpnp)
+{
+	gfs_dirent_t *ge;
+	vnode_t *vp = NULL;
+	int i;
+
+	ASSERT(GFS_DIR_LOCKED(dp));
+
+	/*
 	 * Search static entries.
 	 */
 	for (i = 0; i < dp->gfsd_nstatic; i++) {
 		ge = &dp->gfsd_static[i];
 
-		if (strcmp(ge->gfse_name, nm) == 0) {
+		if (compare(ge->gfse_name, nm) == 0) {
+			if (rpnp)
+				(void) strlcpy(rpnp->pn_buf, ge->gfse_name,
+				    rpnp->pn_bufsize);
+
 			if (ge->gfse_vnode) {
 				ASSERT(ge->gfse_flags & GFS_CACHE_VNODE);
 				vp = ge->gfse_vnode;
 				VN_HOLD(vp);
-				goto out;
+				break;
 			}
 
 			/*
@@ -626,8 +771,8 @@ gfs_dir_lookup(vnode_t *dvp, const char *nm, vnode_t **vpp)
 			 * need to do KM_SLEEP allocations.  If we return from
 			 * the constructor only to find that a parallel
 			 * operation has completed, and GFS_CACHE_VNODE is set
-			 * for this entry, we discard the result in favor of the
-			 * cached vnode.
+			 * for this entry, we discard the result in favor of
+			 * the cached vnode.
 			 */
 			gfs_dir_unlock(dp);
 			vp = ge->gfse_ctor(dvp);
@@ -660,49 +805,94 @@ gfs_dir_lookup(vnode_t *dvp, const char *nm, vnode_t **vpp)
 					gfs_dir_lock(dp);
 				}
 			}
-
-			goto out;
+			break;
 		}
 	}
 
-	/*
-	 * See if there is a dynamic constructor.
-	 */
-	if (dp->gfsd_lookup) {
-		ino64_t ino;
-		gfs_file_t *fp;
+	if (vp == NULL)
+		return (ENOENT);
+	else if (idx)
+		*idx = i;
+	*vpp = vp;
+	return (0);
+}
 
-		/*
-		 * Once again, drop the directory lock, as the lookup routine
-		 * will need to allocate memory, or otherwise deadlock on this
-		 * directory.
-		 */
-		gfs_dir_unlock(dp);
-		ret = dp->gfsd_lookup(dvp, nm, &vp, &ino);
-		gfs_dir_lock(dp);
-		if (ret != 0)
-			goto out;
+/*
+ * gfs_dir_lookup()
+ *
+ * Looks up the given name in the directory and returns the corresponding
+ * vnode, if found.
+ *
+ * First, we search statically defined entries, if any, with a call to
+ * gfs_dir_lookup_static().  If no static entry is found, and we have
+ * a callback function we try a dynamic lookup via gfs_dir_lookup_dynamic().
+ *
+ * This function returns 0 on success, non-zero on error.
+ */
+int
+gfs_dir_lookup(vnode_t *dvp, const char *nm, vnode_t **vpp, cred_t *cr,
+    int flags, int *direntflags, pathname_t *realpnp)
+{
+	gfs_dir_t *dp = dvp->v_data;
+	boolean_t casecheck;
+	vnode_t *dynvp = NULL;
+	vnode_t *vp = NULL;
+	int (*compare)(const char *, const char *);
+	int error, idx;
 
-		fp = (gfs_file_t *)vp->v_data;
-		fp->gfs_index = -1;
-		fp->gfs_ino = ino;
-	} else {
-		/*
-		 * No static entry found, and there is no lookup callback, so
-		 * return ENOENT.
-		 */
-		ret = ENOENT;
+	ASSERT(dvp->v_type == VDIR);
+
+	if (gfs_lookup_dot(vpp, dvp, dp->gfsd_file.gfs_parent, nm) == 0)
+		return (0);
+
+	casecheck = (flags & FIGNORECASE) != 0 && direntflags != NULL;
+	if (vfs_has_feature(dvp->v_vfsp, VFSFT_NOCASESENSITIVE) ||
+	    (flags & FIGNORECASE))
+		compare = strcasecmp;
+	else
+		compare = strcmp;
+
+	gfs_dir_lock(dp);
+
+	error = gfs_dir_lookup_static(compare, dp, nm, dvp, &idx, &vp, realpnp);
+
+	if (vp && casecheck) {
+		gfs_dirent_t *ge;
+		int i;
+
+		for (i = idx + 1; i < dp->gfsd_nstatic; i++) {
+			ge = &dp->gfsd_static[i];
+
+			if (strcasecmp(ge->gfse_name, nm) == 0) {
+				*direntflags |= ED_CASE_CONFLICT;
+				goto out;
+			}
+		}
+	}
+
+	if ((error || casecheck) && dp->gfsd_lookup)
+		error = gfs_dir_lookup_dynamic(dp->gfsd_lookup, dp, nm, dvp,
+		    &dynvp, cr, flags, direntflags, vp ? NULL : realpnp);
+
+	if (vp && dynvp) {
+		/* static and dynamic entries are case-insensitive conflict */
+		ASSERT(casecheck);
+		*direntflags |= ED_CASE_CONFLICT;
+		VN_RELE(dynvp);
+	} else if (vp == NULL) {
+		vp = dynvp;
+	} else if (error == ENOENT) {
+		error = 0;
+	} else if (error) {
+		VN_RELE(vp);
+		vp = NULL;
 	}
 
 out:
 	gfs_dir_unlock(dp);
 
-	if (ret == 0)
-		*vpp = vp;
-	else
-		*vpp = NULL;
-
-	return (ret);
+	*vpp = vp;
+	return (error);
 }
 
 /*
@@ -731,13 +921,15 @@ out:
  * This is significantly more complex, thanks to the particulars of
  * VOP_READDIR().
  *
- *	int gfs_readdir_cb(vnode_t *vp, struct dirent64 *dp, int *eofp,
- *	    offset_t *off, offset_t *nextoff, void *data)
+ *	int gfs_readdir_cb(vnode_t *vp, void *dp, int *eofp,
+ *	    offset_t *off, offset_t *nextoff, void *data, int flags)
  *
  *	vp	- directory vnode
  *	dp	- directory entry, sized according to maxlen given to
  *		  gfs_dir_create().  callback must fill in d_name and
- *		  d_ino.
+ *		  d_ino (if a dirent64_t), or ed_name, ed_ino, and ed_eflags
+ *		  (if an edirent_t). edirent_t is used if V_RDDIR_ENTFLAGS
+ *		  is set in 'flags'.
  *	eofp	- callback must set to 1 when EOF has been reached
  *	off	- on entry, the last offset read from the directory.  Callback
  *		  must set to the offset of the current entry, typically left
@@ -745,12 +937,13 @@ out:
  *	nextoff	- callback must set to offset of next entry.  Typically
  *		  (off + 1)
  *	data	- caller-supplied data
+ *	flags	- VOP_READDIR flags
  *
  *	Return 0 on success, or error on failure.
  */
 int
 gfs_dir_readdir(vnode_t *dvp, uio_t *uiop, int *eofp, int *ncookies,
-    u_long **cookies, void *data)
+    u_long **cookies, void *data, cred_t *cr, int flags)
 {
 	gfs_readdir_state_t gstate;
 	int error, eof = 0;
@@ -758,16 +951,12 @@ gfs_dir_readdir(vnode_t *dvp, uio_t *uiop, int *eofp, int *ncookies,
 	offset_t off, next;
 	gfs_dir_t *dp = dvp->v_data;
 
-	ino = dp->gfsd_file.gfs_ino;
-
-	if (dp->gfsd_file.gfs_parent == NULL)
-		pino = ino;		/* root of filesystem */
-	else
-		pino = ((gfs_file_t *)
-		    (dp->gfsd_file.gfs_parent->v_data))->gfs_ino;
+	error = gfs_get_parent_ino(dvp, cr, NULL, &pino, &ino);
+	if (error)
+		return (error);
 
 	if ((error = gfs_readdir_init(&gstate, dp->gfsd_maxlen, 1, uiop,
-	    pino, ino)) != 0)
+	    pino, ino, flags)) != 0)
 		return (error);
 
 	while ((error = gfs_readdir_pred(&gstate, uiop, &off, ncookies,
@@ -777,8 +966,8 @@ gfs_dir_readdir(vnode_t *dvp, uio_t *uiop, int *eofp, int *ncookies,
 			ino = dp->gfsd_inode(dvp, off);
 
 			if ((error = gfs_readdir_emit(&gstate, uiop,
-			    off, ino, dp->gfsd_static[off].gfse_name, ncookies,
-			    cookies)) != 0)
+			    off, ino, dp->gfsd_static[off].gfse_name, 0,
+			    ncookies, cookies)) != 0)
 				break;
 
 		} else if (dp->gfsd_readdir) {
@@ -786,7 +975,7 @@ gfs_dir_readdir(vnode_t *dvp, uio_t *uiop, int *eofp, int *ncookies,
 
 			if ((error = dp->gfsd_readdir(dvp,
 			    gstate.grd_dirent, &eof, &off, &next,
-			    data)) != 0 || eof)
+			    data, flags)) != 0 || eof)
 				break;
 
 			off += dp->gfsd_nstatic + 2;
@@ -808,6 +997,21 @@ gfs_dir_readdir(vnode_t *dvp, uio_t *uiop, int *eofp, int *ncookies,
 }
 
 /*
+ * gfs_vop_lookup: VOP_LOOKUP() entry point
+ *
+ * For use directly in vnode ops table.  Given a GFS directory, calls
+ * gfs_dir_lookup() as necessary.
+ */
+/* ARGSUSED */
+int
+gfs_vop_lookup(vnode_t *dvp, char *nm, vnode_t **vpp, pathname_t *pnp,
+    int flags, vnode_t *rdir, cred_t *cr, caller_context_t *ct,
+    int *direntflags, pathname_t *realpnp)
+{
+	return (gfs_dir_lookup(dvp, nm, vpp, cr, flags, direntflags, realpnp));
+}
+
+/*
  * gfs_vop_readdir: VOP_READDIR() entry point
  *
  * For use directly in vnode ops table.  Given a GFS directory, calls
@@ -827,6 +1031,7 @@ gfs_vop_readdir(ap)
 {
 	vnode_t *vp = ap->a_vp;
 	uio_t *uiop = ap->a_uio;
+	cred_t *cr = ap->a_cred;
 	int *eofp = ap->a_eofflag;
 	int ncookies = 0;
 	u_long *cookies = NULL;
@@ -842,7 +1047,8 @@ gfs_vop_readdir(ap)
 		*ap->a_ncookies = ncookies;
 	}
 
-	error = gfs_dir_readdir(vp, uiop, eofp, &ncookies, &cookies, NULL);
+	error = gfs_dir_readdir(vp, uiop, eofp, &ncookies, &cookies, NULL,
+	    cr, 0);
 
 	if (error == 0) {
 		/* Subtract unused cookies */
@@ -882,6 +1088,9 @@ gfs_vop_inactive(ap)
 
 	if (data != NULL)
 		kmem_free(data, fp->gfs_size);
+
+	VI_LOCK(vp);
 	vp->v_data = NULL;
+	VI_UNLOCK(vp);
 	return (0);
 }
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/vnode.c b/sys/cddl/contrib/opensolaris/uts/common/fs/vnode.c
new file mode 100644
index 000000000000..00a10aae8ec9
--- /dev/null
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/vnode.c
@@ -0,0 +1,74 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License (the "License").
+ * You may not use this file except in compliance with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or http://www.opensolaris.org/os/licensing.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+/*
+ * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+ * Use is subject to license terms.
+ */
+
+/*	Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T	*/
+/*	  All Rights Reserved  	*/
+
+/*
+ * University Copyright- Copyright (c) 1982, 1986, 1988
+ * The Regents of the University of California
+ * All Rights Reserved
+ *
+ * University Acknowledgment- Portions of this document are derived from
+ * software developed by the University of California, Berkeley, and its
+ * contributors.
+ */
+
+
+#pragma ident	"%Z%%M%	%I%	%E% SMI"
+
+#include <sys/types.h>
+#include <sys/param.h>
+#include <sys/vnode.h>
+
+/* Extensible attribute (xva) routines. */
+
+/*
+ * Zero out the structure, set the size of the requested/returned bitmaps,
+ * set AT_XVATTR in the embedded vattr_t's va_mask, and set up the pointer
+ * to the returned attributes array.
+ */
+void
+xva_init(xvattr_t *xvap)
+{
+	bzero(xvap, sizeof (xvattr_t));
+	xvap->xva_mapsize = XVA_MAPSIZE;
+	xvap->xva_magic = XVA_MAGIC;
+	xvap->xva_vattr.va_mask = AT_XVATTR;
+	xvap->xva_rtnattrmapp = &(xvap->xva_rtnattrmap)[0];
+}
+
+/*
+ * If AT_XVATTR is set, returns a pointer to the embedded xoptattr_t
+ * structure.  Otherwise, returns NULL.
+ */
+xoptattr_t *
+xva_getxoptattr(xvattr_t *xvap)
+{
+	xoptattr_t *xoap = NULL;
+	if (xvap->xva_vattr.va_mask & AT_XVATTR)
+		xoap = &xvap->xva_xoptattrs;
+	return (xoap);
+}
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c
index 420f802f360d..7ca528033c4f 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c
@@ -19,12 +19,10 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
-#pragma ident	"%Z%%M%	%I%	%E% SMI"
-
 /*
  * DVA-based Adjustable Replacement Cache
  *
@@ -47,13 +45,13 @@
  * There are times when it is not possible to evict the requested
  * space.  In these circumstances we are unable to adjust the cache
  * size.  To prevent the cache growing unbounded at these times we
- * implement a "cache throttle" that slowes the flow of new data
- * into the cache until we can make space avaiable.
+ * implement a "cache throttle" that slows the flow of new data
+ * into the cache until we can make space available.
  *
  * 2. The Megiddo and Modha model assumes a fixed cache size.
  * Pages are evicted when the cache is full and there is a cache
  * miss.  Our model has a variable sized cache.  It grows with
- * high use, but also tries to react to memory preasure from the
+ * high use, but also tries to react to memory pressure from the
  * operating system: decreasing its size when system memory is
  * tight.
  *
@@ -75,7 +73,7 @@
  *
  * A new reference to a cache buffer can be obtained in two
  * ways: 1) via a hash table lookup using the DVA as a key,
- * or 2) via one of the ARC lists.  The arc_read() inerface
+ * or 2) via one of the ARC lists.  The arc_read() interface
  * uses method 1, while the internal arc algorithms for
  * adjusting the cache use method 2.  We therefor provide two
  * types of locks: 1) the hash table lock array, and 2) the
@@ -109,6 +107,14 @@
  *
  * Note that the majority of the performance stats are manipulated
  * with atomic operations.
+ *
+ * The L2ARC uses the l2arc_buflist_mtx global mutex for the following:
+ *
+ *	- L2ARC buflist creation
+ *	- L2ARC buflist eviction
+ *	- L2ARC write completion, which walks L2ARC buflists
+ *	- ARC header destruction, as it removes from L2ARC buflists
+ *	- ARC header release, as it removes from L2ARC buflists
  */
 
 #include <sys/spa.h>
@@ -117,6 +123,7 @@
 #include <sys/zfs_context.h>
 #include <sys/arc.h>
 #include <sys/refcount.h>
+#include <sys/vdev.h>
 #ifdef _KERNEL
 #include <sys/dnlc.h>
 #endif
@@ -128,6 +135,10 @@ static kmutex_t		arc_reclaim_thr_lock;
 static kcondvar_t	arc_reclaim_thr_cv;	/* used to signal reclaim thr */
 static uint8_t		arc_thread_exit;
 
+extern int zfs_write_limit_shift;
+extern uint64_t zfs_write_limit_max;
+extern kmutex_t zfs_write_limit_lock;
+
 #define	ARC_REDUCE_DNLC_PERCENT	3
 uint_t arc_reduce_dnlc_percent = ARC_REDUCE_DNLC_PERCENT;
 
@@ -148,28 +159,45 @@ static int		arc_min_prefetch_lifespan;
 static int arc_dead;
 
 /*
+ * The arc has filled available memory and has now warmed up.
+ */
+static boolean_t arc_warm;
+
+/*
  * These tunables are for performance analysis.
  */
-u_long zfs_arc_max;
-u_long zfs_arc_min;
-TUNABLE_ULONG("vfs.zfs.arc_max", &zfs_arc_max);
-TUNABLE_ULONG("vfs.zfs.arc_min", &zfs_arc_min);
+uint64_t zfs_arc_max;
+uint64_t zfs_arc_min;
+uint64_t zfs_arc_meta_limit = 0;
+int zfs_mdcomp_disable = 0;
+
+TUNABLE_QUAD("vfs.zfs.arc_max", &zfs_arc_max);
+TUNABLE_QUAD("vfs.zfs.arc_min", &zfs_arc_min);
+TUNABLE_QUAD("vfs.zfs.arc_meta_limit", &zfs_arc_meta_limit);
+TUNABLE_INT("vfs.zfs.mdcomp_disable", &zfs_mdcomp_disable);
 SYSCTL_DECL(_vfs_zfs);
-SYSCTL_ULONG(_vfs_zfs, OID_AUTO, arc_max, CTLFLAG_RDTUN, &zfs_arc_max, 0,
+SYSCTL_QUAD(_vfs_zfs, OID_AUTO, arc_max, CTLFLAG_RDTUN, &zfs_arc_max, 0,
     "Maximum ARC size");
-SYSCTL_ULONG(_vfs_zfs, OID_AUTO, arc_min, CTLFLAG_RDTUN, &zfs_arc_min, 0,
+SYSCTL_QUAD(_vfs_zfs, OID_AUTO, arc_min, CTLFLAG_RDTUN, &zfs_arc_min, 0,
     "Minimum ARC size");
+SYSCTL_INT(_vfs_zfs, OID_AUTO, mdcomp_disable, CTLFLAG_RDTUN,
+    &zfs_mdcomp_disable, 0, "Disable metadata compression");
 
 /*
- * Note that buffers can be on one of 5 states:
+ * Note that buffers can be in one of 6 states:
  *	ARC_anon	- anonymous (discussed below)
  *	ARC_mru		- recently used, currently cached
  *	ARC_mru_ghost	- recentely used, no longer in cache
  *	ARC_mfu		- frequently used, currently cached
  *	ARC_mfu_ghost	- frequently used, no longer in cache
- * When there are no active references to the buffer, they
- * are linked onto one of the lists in arc.  These are the
- * only buffers that can be evicted or deleted.
+ *	ARC_l2c_only	- exists in L2ARC but not other states
+ * When there are no active references to the buffer, they are
+ * are linked onto a list in one of these arc states.  These are
+ * the only buffers that can be evicted or deleted.  Within each
+ * state there are multiple lists, one for meta-data and one for
+ * non-meta-data.  Meta-data (indirect blocks, blocks of dnodes,
+ * etc.) is tracked separately so that it can be managed more
+ * explicitly: favored over data, limited explicitly.
  *
  * Anonymous buffers are buffers that are not associated with
  * a DVA.  These are buffers that hold dirty block copies
@@ -177,21 +205,30 @@ SYSCTL_ULONG(_vfs_zfs, OID_AUTO, arc_min, CTLFLAG_RDTUN, &zfs_arc_min, 0,
  * they are "ref'd" and are considered part of arc_mru
  * that cannot be freed.  Generally, they will aquire a DVA
  * as they are written and migrate onto the arc_mru list.
+ *
+ * The ARC_l2c_only state is for buffers that are in the second
+ * level ARC but no longer in any of the ARC_m* lists.  The second
+ * level ARC itself may also contain buffers that are in any of
+ * the ARC_m* states - meaning that a buffer can exist in two
+ * places.  The reason for the ARC_l2c_only state is to keep the
+ * buffer header in the hash table, so that reads that hit the
+ * second level ARC benefit from these fast lookups.
  */
 
 typedef struct arc_state {
-	list_t	arcs_list;	/* linked list of evictable buffer in state */
-	uint64_t arcs_lsize;	/* total size of buffers in the linked list */
-	uint64_t arcs_size;	/* total size of all buffers in this state */
+	list_t	arcs_list[ARC_BUFC_NUMTYPES];	/* list of evictable buffers */
+	uint64_t arcs_lsize[ARC_BUFC_NUMTYPES];	/* amount of evictable data */
+	uint64_t arcs_size;	/* total amount of data in this state */
 	kmutex_t arcs_mtx;
 } arc_state_t;
 
-/* The 5 states: */
+/* The 6 states: */
 static arc_state_t ARC_anon;
 static arc_state_t ARC_mru;
 static arc_state_t ARC_mru_ghost;
 static arc_state_t ARC_mfu;
 static arc_state_t ARC_mfu_ghost;
+static arc_state_t ARC_l2c_only;
 
 typedef struct arc_stats {
 	kstat_named_t arcstat_hits;
@@ -222,6 +259,24 @@ typedef struct arc_stats {
 	kstat_named_t arcstat_c_min;
 	kstat_named_t arcstat_c_max;
 	kstat_named_t arcstat_size;
+	kstat_named_t arcstat_hdr_size;
+	kstat_named_t arcstat_l2_hits;
+	kstat_named_t arcstat_l2_misses;
+	kstat_named_t arcstat_l2_feeds;
+	kstat_named_t arcstat_l2_rw_clash;
+	kstat_named_t arcstat_l2_writes_sent;
+	kstat_named_t arcstat_l2_writes_done;
+	kstat_named_t arcstat_l2_writes_error;
+	kstat_named_t arcstat_l2_writes_hdr_miss;
+	kstat_named_t arcstat_l2_evict_lock_retry;
+	kstat_named_t arcstat_l2_evict_reading;
+	kstat_named_t arcstat_l2_free_on_write;
+	kstat_named_t arcstat_l2_abort_lowmem;
+	kstat_named_t arcstat_l2_cksum_bad;
+	kstat_named_t arcstat_l2_io_error;
+	kstat_named_t arcstat_l2_size;
+	kstat_named_t arcstat_l2_hdr_size;
+	kstat_named_t arcstat_memory_throttle_count;
 } arc_stats_t;
 
 static arc_stats_t arc_stats = {
@@ -252,7 +307,25 @@ static arc_stats_t arc_stats = {
 	{ "c",				KSTAT_DATA_UINT64 },
 	{ "c_min",			KSTAT_DATA_UINT64 },
 	{ "c_max",			KSTAT_DATA_UINT64 },
-	{ "size",			KSTAT_DATA_UINT64 }
+	{ "size",			KSTAT_DATA_UINT64 },
+	{ "hdr_size",			KSTAT_DATA_UINT64 },
+	{ "l2_hits",			KSTAT_DATA_UINT64 },
+	{ "l2_misses",			KSTAT_DATA_UINT64 },
+	{ "l2_feeds",			KSTAT_DATA_UINT64 },
+	{ "l2_rw_clash",		KSTAT_DATA_UINT64 },
+	{ "l2_writes_sent",		KSTAT_DATA_UINT64 },
+	{ "l2_writes_done",		KSTAT_DATA_UINT64 },
+	{ "l2_writes_error",		KSTAT_DATA_UINT64 },
+	{ "l2_writes_hdr_miss",		KSTAT_DATA_UINT64 },
+	{ "l2_evict_lock_retry",	KSTAT_DATA_UINT64 },
+	{ "l2_evict_reading",		KSTAT_DATA_UINT64 },
+	{ "l2_free_on_write",		KSTAT_DATA_UINT64 },
+	{ "l2_abort_lowmem",		KSTAT_DATA_UINT64 },
+	{ "l2_cksum_bad",		KSTAT_DATA_UINT64 },
+	{ "l2_io_error",		KSTAT_DATA_UINT64 },
+	{ "l2_size",			KSTAT_DATA_UINT64 },
+	{ "l2_hdr_size",		KSTAT_DATA_UINT64 },
+	{ "memory_throttle_count",	KSTAT_DATA_UINT64 }
 };
 
 #define	ARCSTAT(stat)	(arc_stats.stat.value.ui64)
@@ -299,6 +372,7 @@ static arc_state_t	*arc_mru;
 static arc_state_t	*arc_mru_ghost;
 static arc_state_t	*arc_mfu;
 static arc_state_t	*arc_mfu_ghost;
+static arc_state_t	*arc_l2c_only;
 
 /*
  * There are several ARC variables that are critical to export as kstats --
@@ -316,13 +390,21 @@ static arc_state_t	*arc_mfu_ghost;
 
 static int		arc_no_grow;	/* Don't try to grow cache size */
 static uint64_t		arc_tempreserve;
+static uint64_t		arc_meta_used;
+static uint64_t		arc_meta_limit;
+static uint64_t		arc_meta_max = 0;
+SYSCTL_QUAD(_vfs_zfs, OID_AUTO, arc_meta_used, CTLFLAG_RDTUN,
+    &arc_meta_used, 0, "ARC metadata used");
+SYSCTL_QUAD(_vfs_zfs, OID_AUTO, arc_meta_limit, CTLFLAG_RDTUN,
+    &arc_meta_limit, 0, "ARC metadata limit");
+
+typedef struct l2arc_buf_hdr l2arc_buf_hdr_t;
 
 typedef struct arc_callback arc_callback_t;
 
 struct arc_callback {
 	void			*acb_private;
 	arc_done_func_t		*acb_done;
-	arc_byteswap_func_t	*acb_byteswap;
 	arc_buf_t		*acb_buf;
 	zio_t			*acb_zio_dummy;
 	arc_callback_t		*acb_next;
@@ -368,6 +450,9 @@ struct arc_buf_hdr {
 
 	/* self protecting */
 	refcount_t		b_refcnt;
+
+	l2arc_buf_hdr_t		*b_l2hdr;
+	list_node_t		b_l2node;
 };
 
 static arc_buf_t *arc_eviction_list;
@@ -375,9 +460,12 @@ static kmutex_t arc_eviction_mtx;
 static arc_buf_hdr_t arc_eviction_hdr;
 static void arc_get_data_buf(arc_buf_t *buf);
 static void arc_access(arc_buf_hdr_t *buf, kmutex_t *hash_lock);
+static int arc_evict_needed(arc_buf_contents_t type);
+static void arc_evict_ghost(arc_state_t *state, spa_t *spa, int64_t bytes);
 
 #define	GHOST_STATE(state)	\
-	((state) == arc_mru_ghost || (state) == arc_mfu_ghost)
+	((state) == arc_mru_ghost || (state) == arc_mfu_ghost ||	\
+	(state) == arc_l2c_only)
 
 /*
  * Private ARC flags.  These flags are private ARC only flags that will show up
@@ -393,12 +481,31 @@ static void arc_access(arc_buf_hdr_t *buf, kmutex_t *hash_lock);
 #define	ARC_FREED_IN_READ	(1 << 12)	/* buf freed while in read */
 #define	ARC_BUF_AVAILABLE	(1 << 13)	/* block not in active use */
 #define	ARC_INDIRECT		(1 << 14)	/* this is an indirect block */
+#define	ARC_FREE_IN_PROGRESS	(1 << 15)	/* hdr about to be freed */
+#define	ARC_L2_WRITING		(1 << 16)	/* L2ARC write in progress */
+#define	ARC_L2_EVICTED		(1 << 17)	/* evicted during I/O */
+#define	ARC_L2_WRITE_HEAD	(1 << 18)	/* head of write list */
+#define	ARC_STORED		(1 << 19)	/* has been store()d to */
 
 #define	HDR_IN_HASH_TABLE(hdr)	((hdr)->b_flags & ARC_IN_HASH_TABLE)
 #define	HDR_IO_IN_PROGRESS(hdr)	((hdr)->b_flags & ARC_IO_IN_PROGRESS)
 #define	HDR_IO_ERROR(hdr)	((hdr)->b_flags & ARC_IO_ERROR)
 #define	HDR_FREED_IN_READ(hdr)	((hdr)->b_flags & ARC_FREED_IN_READ)
 #define	HDR_BUF_AVAILABLE(hdr)	((hdr)->b_flags & ARC_BUF_AVAILABLE)
+#define	HDR_FREE_IN_PROGRESS(hdr)	((hdr)->b_flags & ARC_FREE_IN_PROGRESS)
+#define	HDR_L2CACHE(hdr)	((hdr)->b_flags & ARC_L2CACHE)
+#define	HDR_L2_READING(hdr)	((hdr)->b_flags & ARC_IO_IN_PROGRESS &&	\
+				    (hdr)->b_l2hdr != NULL)
+#define	HDR_L2_WRITING(hdr)	((hdr)->b_flags & ARC_L2_WRITING)
+#define	HDR_L2_EVICTED(hdr)	((hdr)->b_flags & ARC_L2_EVICTED)
+#define	HDR_L2_WRITE_HEAD(hdr)	((hdr)->b_flags & ARC_L2_WRITE_HEAD)
+
+/*
+ * Other sizes
+ */
+
+#define	HDR_SIZE ((int64_t)sizeof (arc_buf_hdr_t))
+#define	L2HDR_SIZE ((int64_t)sizeof (l2arc_buf_hdr_t))
 
 /*
  * Hash table routines
@@ -431,8 +538,90 @@ static buf_hash_table_t buf_hash_table;
 
 uint64_t zfs_crc64_table[256];
 
+/*
+ * Level 2 ARC
+ */
+
+#define	L2ARC_WRITE_SIZE	(8 * 1024 * 1024)	/* initial write max */
+#define	L2ARC_HEADROOM		4		/* num of writes */
+#define	L2ARC_FEED_SECS		1		/* caching interval */
+
+#define	l2arc_writes_sent	ARCSTAT(arcstat_l2_writes_sent)
+#define	l2arc_writes_done	ARCSTAT(arcstat_l2_writes_done)
+
+/*
+ * L2ARC Performance Tunables
+ */
+uint64_t l2arc_write_max = L2ARC_WRITE_SIZE;	/* default max write size */
+uint64_t l2arc_write_boost = L2ARC_WRITE_SIZE;	/* extra write during warmup */
+uint64_t l2arc_headroom = L2ARC_HEADROOM;	/* number of dev writes */
+uint64_t l2arc_feed_secs = L2ARC_FEED_SECS;	/* interval seconds */
+boolean_t l2arc_noprefetch = B_TRUE;		/* don't cache prefetch bufs */
+
+/*
+ * L2ARC Internals
+ */
+typedef struct l2arc_dev {
+	vdev_t			*l2ad_vdev;	/* vdev */
+	spa_t			*l2ad_spa;	/* spa */
+	uint64_t		l2ad_hand;	/* next write location */
+	uint64_t		l2ad_write;	/* desired write size, bytes */
+	uint64_t		l2ad_boost;	/* warmup write boost, bytes */
+	uint64_t		l2ad_start;	/* first addr on device */
+	uint64_t		l2ad_end;	/* last addr on device */
+	uint64_t		l2ad_evict;	/* last addr eviction reached */
+	boolean_t		l2ad_first;	/* first sweep through */
+	list_t			*l2ad_buflist;	/* buffer list */
+	list_node_t		l2ad_node;	/* device list node */
+} l2arc_dev_t;
+
+static list_t L2ARC_dev_list;			/* device list */
+static list_t *l2arc_dev_list;			/* device list pointer */
+static kmutex_t l2arc_dev_mtx;			/* device list mutex */
+static l2arc_dev_t *l2arc_dev_last;		/* last device used */
+static kmutex_t l2arc_buflist_mtx;		/* mutex for all buflists */
+static list_t L2ARC_free_on_write;		/* free after write buf list */
+static list_t *l2arc_free_on_write;		/* free after write list ptr */
+static kmutex_t l2arc_free_on_write_mtx;	/* mutex for list */
+static uint64_t l2arc_ndev;			/* number of devices */
+
+typedef struct l2arc_read_callback {
+	arc_buf_t	*l2rcb_buf;		/* read buffer */
+	spa_t		*l2rcb_spa;		/* spa */
+	blkptr_t	l2rcb_bp;		/* original blkptr */
+	zbookmark_t	l2rcb_zb;		/* original bookmark */
+	int		l2rcb_flags;		/* original flags */
+} l2arc_read_callback_t;
+
+typedef struct l2arc_write_callback {
+	l2arc_dev_t	*l2wcb_dev;		/* device info */
+	arc_buf_hdr_t	*l2wcb_head;		/* head of write buflist */
+} l2arc_write_callback_t;
+
+struct l2arc_buf_hdr {
+	/* protected by arc_buf_hdr  mutex */
+	l2arc_dev_t	*b_dev;			/* L2ARC device */
+	daddr_t		b_daddr;		/* disk address, offset byte */
+};
+
+typedef struct l2arc_data_free {
+	/* protected by l2arc_free_on_write_mtx */
+	void		*l2df_data;
+	size_t		l2df_size;
+	void		(*l2df_func)(void *, size_t);
+	list_node_t	l2df_list_node;
+} l2arc_data_free_t;
+
+static kmutex_t l2arc_feed_thr_lock;
+static kcondvar_t l2arc_feed_thr_cv;
+static uint8_t l2arc_thread_exit;
+
+static void l2arc_read_done(zio_t *zio);
+static void l2arc_hdr_stat_add(void);
+static void l2arc_hdr_stat_remove(void);
+
 static uint64_t
-buf_hash(spa_t *spa, dva_t *dva, uint64_t birth)
+buf_hash(spa_t *spa, const dva_t *dva, uint64_t birth)
 {
 	uintptr_t spav = (uintptr_t)spa;
 	uint8_t *vdva = (uint8_t *)dva;
@@ -460,7 +649,7 @@ buf_hash(spa_t *spa, dva_t *dva, uint64_t birth)
 	((buf)->b_birth == birth) && ((buf)->b_spa == spa)
 
 static arc_buf_hdr_t *
-buf_hash_find(spa_t *spa, dva_t *dva, uint64_t birth, kmutex_t **lockp)
+buf_hash_find(spa_t *spa, const dva_t *dva, uint64_t birth, kmutex_t **lockp)
 {
 	uint64_t idx = BUF_HASH_INDEX(spa, dva, birth);
 	kmutex_t *hash_lock = BUF_HASH_LOCK(idx);
@@ -579,6 +768,20 @@ hdr_cons(void *vbuf, void *unused, int kmflag)
 	bzero(buf, sizeof (arc_buf_hdr_t));
 	refcount_create(&buf->b_refcnt);
 	cv_init(&buf->b_cv, NULL, CV_DEFAULT, NULL);
+	mutex_init(&buf->b_freeze_lock, NULL, MUTEX_DEFAULT, NULL);
+
+	ARCSTAT_INCR(arcstat_hdr_size, HDR_SIZE);
+	return (0);
+}
+
+/* ARGSUSED */
+static int
+buf_cons(void *vbuf, void *unused, int kmflag)
+{
+	arc_buf_t *buf = vbuf;
+
+	bzero(buf, sizeof (arc_buf_t));
+	rw_init(&buf->b_lock, NULL, RW_DEFAULT, NULL);
 	return (0);
 }
 
@@ -594,6 +797,18 @@ hdr_dest(void *vbuf, void *unused)
 
 	refcount_destroy(&buf->b_refcnt);
 	cv_destroy(&buf->b_cv);
+	mutex_destroy(&buf->b_freeze_lock);
+
+	ARCSTAT_INCR(arcstat_hdr_size, -HDR_SIZE);
+}
+
+/* ARGSUSED */
+static void
+buf_dest(void *vbuf, void *unused)
+{
+	arc_buf_t *buf = vbuf;
+
+	rw_destroy(&buf->b_lock);
 }
 
 /*
@@ -639,7 +854,7 @@ retry:
 	hdr_cache = kmem_cache_create("arc_buf_hdr_t", sizeof (arc_buf_hdr_t),
 	    0, hdr_cons, hdr_dest, hdr_recl, NULL, NULL, 0);
 	buf_cache = kmem_cache_create("arc_buf_t", sizeof (arc_buf_t),
-	    0, NULL, NULL, NULL, NULL, NULL, 0);
+	    0, buf_cons, buf_dest, NULL, NULL, NULL, 0);
 
 	for (i = 0; i < 256; i++)
 		for (ct = zfs_crc64_table + i, *ct = i, j = 8; j > 0; j--)
@@ -673,10 +888,24 @@ arc_cksum_verify(arc_buf_t *buf)
 	mutex_exit(&buf->b_hdr->b_freeze_lock);
 }
 
+static int
+arc_cksum_equal(arc_buf_t *buf)
+{
+	zio_cksum_t zc;
+	int equal;
+
+	mutex_enter(&buf->b_hdr->b_freeze_lock);
+	fletcher_2_native(buf->b_data, buf->b_hdr->b_size, &zc);
+	equal = ZIO_CHECKSUM_EQUAL(*buf->b_hdr->b_freeze_cksum, zc);
+	mutex_exit(&buf->b_hdr->b_freeze_lock);
+
+	return (equal);
+}
+
 static void
-arc_cksum_compute(arc_buf_t *buf)
+arc_cksum_compute(arc_buf_t *buf, boolean_t force)
 {
-	if (!(zfs_flags & ZFS_DEBUG_MODIFY))
+	if (!force && !(zfs_flags & ZFS_DEBUG_MODIFY))
 		return;
 
 	mutex_enter(&buf->b_hdr->b_freeze_lock);
@@ -693,14 +922,14 @@ arc_cksum_compute(arc_buf_t *buf)
 void
 arc_buf_thaw(arc_buf_t *buf)
 {
-	if (!(zfs_flags & ZFS_DEBUG_MODIFY))
-		return;
+	if (zfs_flags & ZFS_DEBUG_MODIFY) {
+		if (buf->b_hdr->b_state != arc_anon)
+			panic("modifying non-anon buffer!");
+		if (buf->b_hdr->b_flags & ARC_IO_IN_PROGRESS)
+			panic("modifying buffer while i/o in progress!");
+		arc_cksum_verify(buf);
+	}
 
-	if (buf->b_hdr->b_state != arc_anon)
-		panic("modifying non-anon buffer!");
-	if (buf->b_hdr->b_flags & ARC_IO_IN_PROGRESS)
-		panic("modifying buffer while i/o in progress!");
-	arc_cksum_verify(buf);
 	mutex_enter(&buf->b_hdr->b_freeze_lock);
 	if (buf->b_hdr->b_freeze_cksum != NULL) {
 		kmem_free(buf->b_hdr->b_freeze_cksum, sizeof (zio_cksum_t));
@@ -717,7 +946,7 @@ arc_buf_freeze(arc_buf_t *buf)
 
 	ASSERT(buf->b_hdr->b_freeze_cksum != NULL ||
 	    buf->b_hdr->b_state == arc_anon);
-	arc_cksum_compute(buf);
+	arc_cksum_compute(buf, B_FALSE);
 }
 
 static void
@@ -728,21 +957,23 @@ add_reference(arc_buf_hdr_t *ab, kmutex_t *hash_lock, void *tag)
 	if ((refcount_add(&ab->b_refcnt, tag) == 1) &&
 	    (ab->b_state != arc_anon)) {
 		uint64_t delta = ab->b_size * ab->b_datacnt;
+		list_t *list = &ab->b_state->arcs_list[ab->b_type];
+		uint64_t *size = &ab->b_state->arcs_lsize[ab->b_type];
 
 		ASSERT(!MUTEX_HELD(&ab->b_state->arcs_mtx));
 		mutex_enter(&ab->b_state->arcs_mtx);
 		ASSERT(list_link_active(&ab->b_arc_node));
-		list_remove(&ab->b_state->arcs_list, ab);
+		list_remove(list, ab);
 		if (GHOST_STATE(ab->b_state)) {
 			ASSERT3U(ab->b_datacnt, ==, 0);
 			ASSERT3P(ab->b_buf, ==, NULL);
 			delta = ab->b_size;
 		}
 		ASSERT(delta > 0);
-		ASSERT3U(ab->b_state->arcs_lsize, >=, delta);
-		atomic_add_64(&ab->b_state->arcs_lsize, -delta);
+		ASSERT3U(*size, >=, delta);
+		atomic_add_64(size, -delta);
 		mutex_exit(&ab->b_state->arcs_mtx);
-		/* remove the prefetch flag is we get a reference */
+		/* remove the prefetch flag if we get a reference */
 		if (ab->b_flags & ARC_PREFETCH)
 			ab->b_flags &= ~ARC_PREFETCH;
 	}
@@ -759,13 +990,14 @@ remove_reference(arc_buf_hdr_t *ab, kmutex_t *hash_lock, void *tag)
 
 	if (((cnt = refcount_remove(&ab->b_refcnt, tag)) == 0) &&
 	    (state != arc_anon)) {
+		uint64_t *size = &state->arcs_lsize[ab->b_type];
+
 		ASSERT(!MUTEX_HELD(&state->arcs_mtx));
 		mutex_enter(&state->arcs_mtx);
 		ASSERT(!list_link_active(&ab->b_arc_node));
-		list_insert_head(&state->arcs_list, ab);
+		list_insert_head(&state->arcs_list[ab->b_type], ab);
 		ASSERT(ab->b_datacnt > 0);
-		atomic_add_64(&state->arcs_lsize, ab->b_size * ab->b_datacnt);
-		ASSERT3U(state->arcs_size, >=, state->arcs_lsize);
+		atomic_add_64(size, ab->b_size * ab->b_datacnt);
 		mutex_exit(&state->arcs_mtx);
 	}
 	return (cnt);
@@ -796,12 +1028,13 @@ arc_change_state(arc_state_t *new_state, arc_buf_hdr_t *ab, kmutex_t *hash_lock)
 	if (refcnt == 0) {
 		if (old_state != arc_anon) {
 			int use_mutex = !MUTEX_HELD(&old_state->arcs_mtx);
+			uint64_t *size = &old_state->arcs_lsize[ab->b_type];
 
 			if (use_mutex)
 				mutex_enter(&old_state->arcs_mtx);
 
 			ASSERT(list_link_active(&ab->b_arc_node));
-			list_remove(&old_state->arcs_list, ab);
+			list_remove(&old_state->arcs_list[ab->b_type], ab);
 
 			/*
 			 * If prefetching out of the ghost cache,
@@ -812,19 +1045,20 @@ arc_change_state(arc_state_t *new_state, arc_buf_hdr_t *ab, kmutex_t *hash_lock)
 				ASSERT(ab->b_buf == NULL);
 				from_delta = ab->b_size;
 			}
-			ASSERT3U(old_state->arcs_lsize, >=, from_delta);
-			atomic_add_64(&old_state->arcs_lsize, -from_delta);
+			ASSERT3U(*size, >=, from_delta);
+			atomic_add_64(size, -from_delta);
 
 			if (use_mutex)
 				mutex_exit(&old_state->arcs_mtx);
 		}
 		if (new_state != arc_anon) {
 			int use_mutex = !MUTEX_HELD(&new_state->arcs_mtx);
+			uint64_t *size = &new_state->arcs_lsize[ab->b_type];
 
 			if (use_mutex)
 				mutex_enter(&new_state->arcs_mtx);
 
-			list_insert_head(&new_state->arcs_list, ab);
+			list_insert_head(&new_state->arcs_list[ab->b_type], ab);
 
 			/* ghost elements have a ghost size */
 			if (GHOST_STATE(new_state)) {
@@ -832,9 +1066,7 @@ arc_change_state(arc_state_t *new_state, arc_buf_hdr_t *ab, kmutex_t *hash_lock)
 				ASSERT(ab->b_buf == NULL);
 				to_delta = ab->b_size;
 			}
-			atomic_add_64(&new_state->arcs_lsize, to_delta);
-			ASSERT3U(new_state->arcs_size + to_delta, >=,
-			    new_state->arcs_lsize);
+			atomic_add_64(size, to_delta);
 
 			if (use_mutex)
 				mutex_exit(&new_state->arcs_mtx);
@@ -842,7 +1074,7 @@ arc_change_state(arc_state_t *new_state, arc_buf_hdr_t *ab, kmutex_t *hash_lock)
 	}
 
 	ASSERT(!BUF_EMPTY(ab));
-	if (new_state == arc_anon && old_state != arc_anon) {
+	if (new_state == arc_anon) {
 		buf_hash_remove(ab);
 	}
 
@@ -854,6 +1086,47 @@ arc_change_state(arc_state_t *new_state, arc_buf_hdr_t *ab, kmutex_t *hash_lock)
 		atomic_add_64(&old_state->arcs_size, -from_delta);
 	}
 	ab->b_state = new_state;
+
+	/* adjust l2arc hdr stats */
+	if (new_state == arc_l2c_only)
+		l2arc_hdr_stat_add();
+	else if (old_state == arc_l2c_only)
+		l2arc_hdr_stat_remove();
+}
+
+void
+arc_space_consume(uint64_t space)
+{
+	atomic_add_64(&arc_meta_used, space);
+	atomic_add_64(&arc_size, space);
+}
+
+void
+arc_space_return(uint64_t space)
+{
+	ASSERT(arc_meta_used >= space);
+	if (arc_meta_max < arc_meta_used)
+		arc_meta_max = arc_meta_used;
+	atomic_add_64(&arc_meta_used, -space);
+	ASSERT(arc_size >= space);
+	atomic_add_64(&arc_size, -space);
+}
+
+void *
+arc_data_buf_alloc(uint64_t size)
+{
+	if (arc_evict_needed(ARC_BUFC_DATA))
+		cv_signal(&arc_reclaim_thr_cv);
+	atomic_add_64(&arc_size, size);
+	return (zio_data_buf_alloc(size));
+}
+
+void
+arc_data_buf_free(void *buf, uint64_t size)
+{
+	zio_data_buf_free(buf, size);
+	ASSERT(arc_size >= size);
+	atomic_add_64(&arc_size, -size);
 }
 
 arc_buf_t *
@@ -863,15 +1136,14 @@ arc_buf_alloc(spa_t *spa, int size, void *tag, arc_buf_contents_t type)
 	arc_buf_t *buf;
 
 	ASSERT3U(size, >, 0);
-	hdr = kmem_cache_alloc(hdr_cache, KM_SLEEP);
+	hdr = kmem_cache_alloc(hdr_cache, KM_PUSHPAGE);
 	ASSERT(BUF_EMPTY(hdr));
 	hdr->b_size = size;
 	hdr->b_type = type;
 	hdr->b_spa = spa;
 	hdr->b_state = arc_anon;
 	hdr->b_arc_access = 0;
-	mutex_init(&hdr->b_freeze_lock, NULL, MUTEX_DEFAULT, NULL);
-	buf = kmem_cache_alloc(buf_cache, KM_SLEEP);
+	buf = kmem_cache_alloc(buf_cache, KM_PUSHPAGE);
 	buf->b_hdr = hdr;
 	buf->b_data = NULL;
 	buf->b_efunc = NULL;
@@ -894,7 +1166,7 @@ arc_buf_clone(arc_buf_t *from)
 	arc_buf_hdr_t *hdr = from->b_hdr;
 	uint64_t size = hdr->b_size;
 
-	buf = kmem_cache_alloc(buf_cache, KM_SLEEP);
+	buf = kmem_cache_alloc(buf_cache, KM_PUSHPAGE);
 	buf->b_hdr = hdr;
 	buf->b_data = NULL;
 	buf->b_efunc = NULL;
@@ -914,28 +1186,21 @@ arc_buf_add_ref(arc_buf_t *buf, void* tag)
 	kmutex_t *hash_lock;
 
 	/*
-	 * Check to see if this buffer is currently being evicted via
-	 * arc_do_user_evicts().
+	 * Check to see if this buffer is evicted.  Callers
+	 * must verify b_data != NULL to know if the add_ref
+	 * was successful.
 	 */
-	mutex_enter(&arc_eviction_mtx);
-	hdr = buf->b_hdr;
-	if (hdr == NULL) {
-		mutex_exit(&arc_eviction_mtx);
+	rw_enter(&buf->b_lock, RW_READER);
+	if (buf->b_data == NULL) {
+		rw_exit(&buf->b_lock);
 		return;
 	}
+	hdr = buf->b_hdr;
+	ASSERT(hdr != NULL);
 	hash_lock = HDR_LOCK(hdr);
-	mutex_exit(&arc_eviction_mtx);
-
 	mutex_enter(hash_lock);
-	if (buf->b_data == NULL) {
-		/*
-		 * This buffer is evicted.
-		 */
-		mutex_exit(hash_lock);
-		return;
-	}
+	rw_exit(&buf->b_lock);
 
-	ASSERT(buf->b_hdr == hdr);
 	ASSERT(hdr->b_state == arc_mru || hdr->b_state == arc_mfu);
 	add_reference(hdr, hash_lock, tag);
 	arc_access(hdr, hash_lock);
@@ -946,6 +1211,29 @@ arc_buf_add_ref(arc_buf_t *buf, void* tag)
 	    data, metadata, hits);
 }
 
+/*
+ * Free the arc data buffer.  If it is an l2arc write in progress,
+ * the buffer is placed on l2arc_free_on_write to be freed later.
+ */
+static void
+arc_buf_data_free(arc_buf_hdr_t *hdr, void (*free_func)(void *, size_t),
+    void *data, size_t size)
+{
+	if (HDR_L2_WRITING(hdr)) {
+		l2arc_data_free_t *df;
+		df = kmem_alloc(sizeof (l2arc_data_free_t), KM_SLEEP);
+		df->l2df_data = data;
+		df->l2df_size = size;
+		df->l2df_func = free_func;
+		mutex_enter(&l2arc_free_on_write_mtx);
+		list_insert_head(l2arc_free_on_write, df);
+		mutex_exit(&l2arc_free_on_write_mtx);
+		ARCSTAT_BUMP(arcstat_l2_free_on_write);
+	} else {
+		free_func(data, size);
+	}
+}
+
 static void
 arc_buf_destroy(arc_buf_t *buf, boolean_t recycle, boolean_t all)
 {
@@ -960,18 +1248,24 @@ arc_buf_destroy(arc_buf_t *buf, boolean_t recycle, boolean_t all)
 		arc_cksum_verify(buf);
 		if (!recycle) {
 			if (type == ARC_BUFC_METADATA) {
-				zio_buf_free(buf->b_data, size);
+				arc_buf_data_free(buf->b_hdr, zio_buf_free,
+				    buf->b_data, size);
+				arc_space_return(size);
 			} else {
 				ASSERT(type == ARC_BUFC_DATA);
-				zio_data_buf_free(buf->b_data, size);
+				arc_buf_data_free(buf->b_hdr,
+				    zio_data_buf_free, buf->b_data, size);
+				atomic_add_64(&arc_size, -size);
 			}
-			atomic_add_64(&arc_size, -size);
 		}
 		if (list_link_active(&buf->b_hdr->b_arc_node)) {
+			uint64_t *cnt = &state->arcs_lsize[type];
+
 			ASSERT(refcount_is_zero(&buf->b_hdr->b_refcnt));
 			ASSERT(state != arc_anon);
-			ASSERT3U(state->arcs_lsize, >=, size);
-			atomic_add_64(&state->arcs_lsize, -size);
+
+			ASSERT3U(*cnt, >=, size);
+			atomic_add_64(cnt, -size);
 		}
 		ASSERT3U(state->arcs_size, >=, size);
 		atomic_add_64(&state->arcs_size, -size);
@@ -1002,6 +1296,35 @@ arc_hdr_destroy(arc_buf_hdr_t *hdr)
 	ASSERT(refcount_is_zero(&hdr->b_refcnt));
 	ASSERT3P(hdr->b_state, ==, arc_anon);
 	ASSERT(!HDR_IO_IN_PROGRESS(hdr));
+	ASSERT(!(hdr->b_flags & ARC_STORED));
+
+	if (hdr->b_l2hdr != NULL) {
+		if (!MUTEX_HELD(&l2arc_buflist_mtx)) {
+			/*
+			 * To prevent arc_free() and l2arc_evict() from
+			 * attempting to free the same buffer at the same time,
+			 * a FREE_IN_PROGRESS flag is given to arc_free() to
+			 * give it priority.  l2arc_evict() can't destroy this
+			 * header while we are waiting on l2arc_buflist_mtx.
+			 *
+			 * The hdr may be removed from l2ad_buflist before we
+			 * grab l2arc_buflist_mtx, so b_l2hdr is rechecked.
+			 */
+			mutex_enter(&l2arc_buflist_mtx);
+			if (hdr->b_l2hdr != NULL) {
+				list_remove(hdr->b_l2hdr->b_dev->l2ad_buflist,
+				    hdr);
+			}
+			mutex_exit(&l2arc_buflist_mtx);
+		} else {
+			list_remove(hdr->b_l2hdr->b_dev->l2ad_buflist, hdr);
+		}
+		ARCSTAT_INCR(arcstat_l2_size, -hdr->b_size);
+		kmem_free(hdr->b_l2hdr, sizeof (l2arc_buf_hdr_t));
+		if (hdr->b_state == arc_l2c_only)
+			l2arc_hdr_stat_remove();
+		hdr->b_l2hdr = NULL;
+	}
 
 	if (!BUF_EMPTY(hdr)) {
 		ASSERT(!HDR_IN_HASH_TABLE(hdr));
@@ -1014,12 +1337,14 @@ arc_hdr_destroy(arc_buf_hdr_t *hdr)
 
 		if (buf->b_efunc) {
 			mutex_enter(&arc_eviction_mtx);
+			rw_enter(&buf->b_lock, RW_WRITER);
 			ASSERT(buf->b_hdr != NULL);
 			arc_buf_destroy(hdr->b_buf, FALSE, FALSE);
 			hdr->b_buf = buf->b_next;
 			buf->b_hdr = &arc_eviction_hdr;
 			buf->b_next = arc_eviction_list;
 			arc_eviction_list = buf;
+			rw_exit(&buf->b_lock);
 			mutex_exit(&arc_eviction_mtx);
 		} else {
 			arc_buf_destroy(hdr->b_buf, FALSE, TRUE);
@@ -1029,7 +1354,6 @@ arc_hdr_destroy(arc_buf_hdr_t *hdr)
 		kmem_free(hdr->b_freeze_cksum, sizeof (zio_cksum_t));
 		hdr->b_freeze_cksum = NULL;
 	}
-	mutex_destroy(&hdr->b_freeze_lock);
 
 	ASSERT(!list_link_active(&hdr->b_arc_node));
 	ASSERT3P(hdr->b_hash_next, ==, NULL);
@@ -1124,14 +1448,19 @@ arc_buf_size(arc_buf_t *buf)
  * - return the data block from this buffer rather than freeing it.
  * This flag is used by callers that are trying to make space for a
  * new buffer in a full arc cache.
+ *
+ * This function makes a "best effort".  It skips over any buffers
+ * it can't get a hash_lock on, and so may not catch all candidates.
+ * It may also return without evicting as much space as requested.
  */
 static void *
-arc_evict(arc_state_t *state, int64_t bytes, boolean_t recycle,
+arc_evict(arc_state_t *state, spa_t *spa, int64_t bytes, boolean_t recycle,
     arc_buf_contents_t type)
 {
 	arc_state_t *evicted_state;
 	uint64_t bytes_evicted = 0, skipped = 0, missed = 0;
 	arc_buf_hdr_t *ab, *ab_prev = NULL;
+	list_t *list = &state->arcs_list[type];
 	kmutex_t *hash_lock;
 	boolean_t have_lock;
 	void *stolen = NULL;
@@ -1143,10 +1472,11 @@ arc_evict(arc_state_t *state, int64_t bytes, boolean_t recycle,
 	mutex_enter(&state->arcs_mtx);
 	mutex_enter(&evicted_state->arcs_mtx);
 
-	for (ab = list_tail(&state->arcs_list); ab; ab = ab_prev) {
-		ab_prev = list_prev(&state->arcs_list, ab);
+	for (ab = list_tail(list); ab; ab = ab_prev) {
+		ab_prev = list_prev(list, ab);
 		/* prefetch buffers have a minimum lifespan */
 		if (HDR_IO_IN_PROGRESS(ab) ||
+		    (spa && ab->b_spa != spa) ||
 		    (ab->b_flags & (ARC_PREFETCH|ARC_INDIRECT) &&
 		    LBOLT - ab->b_arc_access < arc_min_prefetch_lifespan)) {
 			skipped++;
@@ -1163,10 +1493,15 @@ arc_evict(arc_state_t *state, int64_t bytes, boolean_t recycle,
 			ASSERT(ab->b_datacnt > 0);
 			while (ab->b_buf) {
 				arc_buf_t *buf = ab->b_buf;
+				if (!rw_tryenter(&buf->b_lock, RW_WRITER)) {
+					missed += 1;
+					break;
+				}
 				if (buf->b_data) {
 					bytes_evicted += ab->b_size;
 					if (recycle && ab->b_type == type &&
-					    ab->b_size == bytes) {
+					    ab->b_size == bytes &&
+					    !HDR_L2_WRITING(ab)) {
 						stolen = buf->b_data;
 						recycle = FALSE;
 					}
@@ -1180,16 +1515,20 @@ arc_evict(arc_state_t *state, int64_t bytes, boolean_t recycle,
 					buf->b_next = arc_eviction_list;
 					arc_eviction_list = buf;
 					mutex_exit(&arc_eviction_mtx);
+					rw_exit(&buf->b_lock);
 				} else {
+					rw_exit(&buf->b_lock);
 					arc_buf_destroy(buf,
 					    buf->b_data == stolen, TRUE);
 				}
 			}
-			ASSERT(ab->b_datacnt == 0);
-			arc_change_state(evicted_state, ab, hash_lock);
-			ASSERT(HDR_IN_HASH_TABLE(ab));
-			ab->b_flags = ARC_IN_HASH_TABLE;
-			DTRACE_PROBE1(arc__evict, arc_buf_hdr_t *, ab);
+			if (ab->b_datacnt == 0) {
+				arc_change_state(evicted_state, ab, hash_lock);
+				ASSERT(HDR_IN_HASH_TABLE(ab));
+				ab->b_flags |= ARC_IN_HASH_TABLE;
+				ab->b_flags &= ~ARC_BUF_AVAILABLE;
+				DTRACE_PROBE1(arc__evict, arc_buf_hdr_t *, ab);
+			}
 			if (!have_lock)
 				mutex_exit(hash_lock);
 			if (bytes >= 0 && bytes_evicted >= bytes)
@@ -1212,6 +1551,27 @@ arc_evict(arc_state_t *state, int64_t bytes, boolean_t recycle,
 	if (missed)
 		ARCSTAT_INCR(arcstat_mutex_miss, missed);
 
+	/*
+	 * We have just evicted some date into the ghost state, make
+	 * sure we also adjust the ghost state size if necessary.
+	 */
+	if (arc_no_grow &&
+	    arc_mru_ghost->arcs_size + arc_mfu_ghost->arcs_size > arc_c) {
+		int64_t mru_over = arc_anon->arcs_size + arc_mru->arcs_size +
+		    arc_mru_ghost->arcs_size - arc_c;
+
+		if (mru_over > 0 && arc_mru_ghost->arcs_lsize[type] > 0) {
+			int64_t todelete =
+			    MIN(arc_mru_ghost->arcs_lsize[type], mru_over);
+			arc_evict_ghost(arc_mru_ghost, NULL, todelete);
+		} else if (arc_mfu_ghost->arcs_lsize[type] > 0) {
+			int64_t todelete = MIN(arc_mfu_ghost->arcs_lsize[type],
+			    arc_mru_ghost->arcs_size +
+			    arc_mfu_ghost->arcs_size - arc_c);
+			arc_evict_ghost(arc_mfu_ghost, NULL, todelete);
+		}
+	}
+
 	return (stolen);
 }
 
@@ -1220,9 +1580,10 @@ arc_evict(arc_state_t *state, int64_t bytes, boolean_t recycle,
  * bytes.  Destroy the buffers that are removed.
  */
 static void
-arc_evict_ghost(arc_state_t *state, int64_t bytes)
+arc_evict_ghost(arc_state_t *state, spa_t *spa, int64_t bytes)
 {
 	arc_buf_hdr_t *ab, *ab_prev;
+	list_t *list = &state->arcs_list[ARC_BUFC_DATA];
 	kmutex_t *hash_lock;
 	uint64_t bytes_deleted = 0;
 	uint64_t bufs_skipped = 0;
@@ -1230,17 +1591,30 @@ arc_evict_ghost(arc_state_t *state, int64_t bytes)
 	ASSERT(GHOST_STATE(state));
 top:
 	mutex_enter(&state->arcs_mtx);
-	for (ab = list_tail(&state->arcs_list); ab; ab = ab_prev) {
-		ab_prev = list_prev(&state->arcs_list, ab);
+	for (ab = list_tail(list); ab; ab = ab_prev) {
+		ab_prev = list_prev(list, ab);
+		if (spa && ab->b_spa != spa)
+			continue;
 		hash_lock = HDR_LOCK(ab);
 		if (mutex_tryenter(hash_lock)) {
 			ASSERT(!HDR_IO_IN_PROGRESS(ab));
 			ASSERT(ab->b_buf == NULL);
-			arc_change_state(arc_anon, ab, hash_lock);
-			mutex_exit(hash_lock);
 			ARCSTAT_BUMP(arcstat_deleted);
 			bytes_deleted += ab->b_size;
-			arc_hdr_destroy(ab);
+
+			if (ab->b_l2hdr != NULL) {
+				/*
+				 * This buffer is cached on the 2nd Level ARC;
+				 * don't destroy the header.
+				 */
+				arc_change_state(arc_l2c_only, ab, hash_lock);
+				mutex_exit(hash_lock);
+			} else {
+				arc_change_state(arc_anon, ab, hash_lock);
+				mutex_exit(hash_lock);
+				arc_hdr_destroy(ab);
+			}
+
 			DTRACE_PROBE1(arc__delete, arc_buf_hdr_t *, ab);
 			if (bytes >= 0 && bytes_deleted >= bytes)
 				break;
@@ -1256,6 +1630,12 @@ top:
 	}
 	mutex_exit(&state->arcs_mtx);
 
+	if (list == &state->arcs_list[ARC_BUFC_DATA] &&
+	    (bytes < 0 || bytes_deleted < bytes)) {
+		list = &state->arcs_list[ARC_BUFC_METADATA];
+		goto top;
+	}
+
 	if (bufs_skipped) {
 		ARCSTAT_INCR(arcstat_mutex_miss, bufs_skipped);
 		ASSERT(bytes >= 0);
@@ -1271,38 +1651,58 @@ arc_adjust(void)
 {
 	int64_t top_sz, mru_over, arc_over, todelete;
 
-	top_sz = arc_anon->arcs_size + arc_mru->arcs_size;
+	top_sz = arc_anon->arcs_size + arc_mru->arcs_size + arc_meta_used;
+
+	if (top_sz > arc_p && arc_mru->arcs_lsize[ARC_BUFC_DATA] > 0) {
+		int64_t toevict =
+		    MIN(arc_mru->arcs_lsize[ARC_BUFC_DATA], top_sz - arc_p);
+		(void) arc_evict(arc_mru, NULL, toevict, FALSE, ARC_BUFC_DATA);
+		top_sz = arc_anon->arcs_size + arc_mru->arcs_size;
+	}
 
-	if (top_sz > arc_p && arc_mru->arcs_lsize > 0) {
-		int64_t toevict = MIN(arc_mru->arcs_lsize, top_sz - arc_p);
-		(void) arc_evict(arc_mru, toevict, FALSE, ARC_BUFC_UNDEF);
+	if (top_sz > arc_p && arc_mru->arcs_lsize[ARC_BUFC_METADATA] > 0) {
+		int64_t toevict =
+		    MIN(arc_mru->arcs_lsize[ARC_BUFC_METADATA], top_sz - arc_p);
+		(void) arc_evict(arc_mru, NULL, toevict, FALSE,
+		    ARC_BUFC_METADATA);
 		top_sz = arc_anon->arcs_size + arc_mru->arcs_size;
 	}
 
 	mru_over = top_sz + arc_mru_ghost->arcs_size - arc_c;
 
 	if (mru_over > 0) {
-		if (arc_mru_ghost->arcs_lsize > 0) {
-			todelete = MIN(arc_mru_ghost->arcs_lsize, mru_over);
-			arc_evict_ghost(arc_mru_ghost, todelete);
+		if (arc_mru_ghost->arcs_size > 0) {
+			todelete = MIN(arc_mru_ghost->arcs_size, mru_over);
+			arc_evict_ghost(arc_mru_ghost, NULL, todelete);
 		}
 	}
 
 	if ((arc_over = arc_size - arc_c) > 0) {
 		int64_t tbl_over;
 
-		if (arc_mfu->arcs_lsize > 0) {
-			int64_t toevict = MIN(arc_mfu->arcs_lsize, arc_over);
-			(void) arc_evict(arc_mfu, toevict, FALSE,
-			    ARC_BUFC_UNDEF);
+		if (arc_mfu->arcs_lsize[ARC_BUFC_DATA] > 0) {
+			int64_t toevict =
+			    MIN(arc_mfu->arcs_lsize[ARC_BUFC_DATA], arc_over);
+			(void) arc_evict(arc_mfu, NULL, toevict, FALSE,
+			    ARC_BUFC_DATA);
+			arc_over = arc_size - arc_c;
+		}
+
+		if (arc_over > 0 &&
+		    arc_mfu->arcs_lsize[ARC_BUFC_METADATA] > 0) {
+			int64_t toevict =
+			    MIN(arc_mfu->arcs_lsize[ARC_BUFC_METADATA],
+			    arc_over);
+			(void) arc_evict(arc_mfu, NULL, toevict, FALSE,
+			    ARC_BUFC_METADATA);
 		}
 
-		tbl_over = arc_size + arc_mru_ghost->arcs_lsize +
-		    arc_mfu_ghost->arcs_lsize - arc_c*2;
+		tbl_over = arc_size + arc_mru_ghost->arcs_size +
+		    arc_mfu_ghost->arcs_size - arc_c * 2;
 
-		if (tbl_over > 0 && arc_mfu_ghost->arcs_lsize > 0) {
-			todelete = MIN(arc_mfu_ghost->arcs_lsize, tbl_over);
-			arc_evict_ghost(arc_mfu_ghost, todelete);
+		if (tbl_over > 0 && arc_mfu_ghost->arcs_size > 0) {
+			todelete = MIN(arc_mfu_ghost->arcs_size, tbl_over);
+			arc_evict_ghost(arc_mfu_ghost, NULL, todelete);
 		}
 	}
 }
@@ -1314,7 +1714,9 @@ arc_do_user_evicts(void)
 	while (arc_eviction_list != NULL) {
 		arc_buf_t *buf = arc_eviction_list;
 		arc_eviction_list = buf->b_next;
+		rw_enter(&buf->b_lock, RW_WRITER);
 		buf->b_hdr = NULL;
+		rw_exit(&buf->b_lock);
 		mutex_exit(&arc_eviction_mtx);
 
 		if (buf->b_efunc != NULL)
@@ -1329,24 +1731,40 @@ arc_do_user_evicts(void)
 }
 
 /*
- * Flush all *evictable* data from the cache.
+ * Flush all *evictable* data from the cache for the given spa.
  * NOTE: this will not touch "active" (i.e. referenced) data.
  */
 void
-arc_flush(void)
+arc_flush(spa_t *spa)
 {
-	while (list_head(&arc_mru->arcs_list))
-		(void) arc_evict(arc_mru, -1, FALSE, ARC_BUFC_UNDEF);
-	while (list_head(&arc_mfu->arcs_list))
-		(void) arc_evict(arc_mfu, -1, FALSE, ARC_BUFC_UNDEF);
+	while (list_head(&arc_mru->arcs_list[ARC_BUFC_DATA])) {
+		(void) arc_evict(arc_mru, spa, -1, FALSE, ARC_BUFC_DATA);
+		if (spa)
+			break;
+	}
+	while (list_head(&arc_mru->arcs_list[ARC_BUFC_METADATA])) {
+		(void) arc_evict(arc_mru, spa, -1, FALSE, ARC_BUFC_METADATA);
+		if (spa)
+			break;
+	}
+	while (list_head(&arc_mfu->arcs_list[ARC_BUFC_DATA])) {
+		(void) arc_evict(arc_mfu, spa, -1, FALSE, ARC_BUFC_DATA);
+		if (spa)
+			break;
+	}
+	while (list_head(&arc_mfu->arcs_list[ARC_BUFC_METADATA])) {
+		(void) arc_evict(arc_mfu, spa, -1, FALSE, ARC_BUFC_METADATA);
+		if (spa)
+			break;
+	}
 
-	arc_evict_ghost(arc_mru_ghost, -1);
-	arc_evict_ghost(arc_mfu_ghost, -1);
+	arc_evict_ghost(arc_mru_ghost, spa, -1);
+	arc_evict_ghost(arc_mfu_ghost, spa, -1);
 
 	mutex_enter(&arc_reclaim_thr_lock);
 	arc_do_user_evicts();
 	mutex_exit(&arc_reclaim_thr_lock);
-	ASSERT(arc_eviction_list == NULL);
+	ASSERT(spa || arc_eviction_list == NULL);
 }
 
 int arc_shrink_shift = 5;		/* log2(fraction of arc to reclaim) */
@@ -1380,7 +1798,7 @@ arc_shrink(void)
 		arc_adjust();
 }
 
-static int zfs_needfree = 0;
+static int needfree = 0;
 
 static int
 arc_reclaim_needed(void)
@@ -1391,13 +1809,28 @@ arc_reclaim_needed(void)
 
 #ifdef _KERNEL
 
-	if (zfs_needfree)
+	if (needfree)
 		return (1);
 
 #if 0
 	/*
+	 * take 'desfree' extra pages, so we reclaim sooner, rather than later
+	 */
+	extra = desfree;
+
+	/*
+	 * check that we're out of range of the pageout scanner.  It starts to
+	 * schedule paging if freemem is less than lotsfree and needfree.
+	 * lotsfree is the high-water mark for pageout, and needfree is the
+	 * number of needed free pages.  We add extra pages here to make sure
+	 * the scanner doesn't start up while we're freeing memory.
+	 */
+	if (freemem < lotsfree + needfree + extra)
+		return (1);
+
+	/*
 	 * check to make sure that swapfs has enough space so that anon
-	 * reservations can still succeeed. anon_resvmem() checks that the
+	 * reservations can still succeed. anon_resvmem() checks that the
 	 * availrmem is greater than swapfs_minfree, and the number of reserved
 	 * swap pages.  We also add a bit of extra here just to prevent
 	 * circumstances from getting really dire.
@@ -1405,23 +1838,6 @@ arc_reclaim_needed(void)
 	if (availrmem < swapfs_minfree + swapfs_reserve + extra)
 		return (1);
 
-	/*
-	 * If zio data pages are being allocated out of a separate heap segment,
-	 * then check that the size of available vmem for this area remains
-	 * above 1/4th free.  This needs to be done when the size of the
-	 * non-default segment is smaller than physical memory, so we could
-	 * conceivably run out of VA in that segment before running out of
-	 * physical memory.
-	 */
-	if (zio_arena != NULL) {
-		size_t arc_ziosize =
-		    btop(vmem_size(zio_arena, VMEM_FREE | VMEM_ALLOC));
-
-		if ((physmem > arc_ziosize) &&
-		    (btop(vmem_size(zio_arena, VMEM_FREE)) < arc_ziosize >> 2))
-			return (1);
-	}
-
 #if defined(__i386)
 	/*
 	 * If we're on an i386 platform, it's possible that we'll exhaust the
@@ -1431,7 +1847,7 @@ arc_reclaim_needed(void)
 	 * can have in the system.  However, this is generally fixed at 25 pages
 	 * which is so low that it's useless.  In this comparison, we seek to
 	 * calculate the total heap-size, and reclaim if more than 3/4ths of the
-	 * heap is allocated.  (Or, in the caclulation, if less than 1/4th is
+	 * heap is allocated.  (Or, in the calculation, if less than 1/4th is
 	 * free)
 	 */
 	if (btop(vmem_size(heap_arena, VMEM_FREE)) <
@@ -1462,12 +1878,13 @@ arc_kmem_reap_now(arc_reclaim_strategy_t strat)
 #endif
 
 #ifdef _KERNEL
-	/*
-	 * First purge some DNLC entries, in case the DNLC is using
-	 * up too much memory.
-	 */
-	dnlc_reduce_cache((void *)(uintptr_t)arc_reduce_dnlc_percent);
-
+	if (arc_meta_used >= arc_meta_limit) {
+		/*
+		 * We are exceeding our meta-data cache limit.
+		 * Purge some DNLC entries to release holds on meta-data.
+		 */
+		dnlc_reduce_cache((void *)(uintptr_t)arc_reduce_dnlc_percent);
+	}
 #if defined(__i386)
 	/*
 	 * Reclaim unused memory from all kmem caches.
@@ -1477,7 +1894,7 @@ arc_kmem_reap_now(arc_reclaim_strategy_t strat)
 #endif
 
 	/*
-	 * An agressive reclamation will shrink the cache size as well as
+	 * An aggressive reclamation will shrink the cache size as well as
 	 * reap free buffers from the arc kmem caches.
 	 */
 	if (strat == ARC_RECLAIM_AGGR)
@@ -1526,11 +1943,10 @@ arc_reclaim_thread(void *dummy __unused)
 
 			/* reset the growth delay for every reclaim */
 			growtime = LBOLT + (arc_grow_retry * hz);
-			ASSERT(growtime > 0);
 
-			if (zfs_needfree && last_reclaim == ARC_RECLAIM_CONS) {
+			if (needfree && last_reclaim == ARC_RECLAIM_CONS) {
 				/*
-				 * If zfs_needfree is TRUE our vm_lowmem hook
+				 * If needfree is TRUE our vm_lowmem hook
 				 * was called and in that case we must free some
 				 * memory, so switch to aggressive mode.
 				 */
@@ -1538,11 +1954,13 @@ arc_reclaim_thread(void *dummy __unused)
 				last_reclaim = ARC_RECLAIM_AGGR;
 			}
 			arc_kmem_reap_now(last_reclaim);
-		} else if ((growtime > 0) && ((growtime - LBOLT) <= 0)) {
+			arc_warm = B_TRUE;
+
+		} else if (arc_no_grow && LBOLT >= growtime) {
 			arc_no_grow = FALSE;
 		}
 
-		if (zfs_needfree ||
+		if (needfree ||
 		    (2 * arc_c < arc_size +
 		    arc_mru_ghost->arcs_size + arc_mfu_ghost->arcs_size))
 			arc_adjust();
@@ -1551,9 +1969,9 @@ arc_reclaim_thread(void *dummy __unused)
 			arc_do_user_evicts();
 
 		if (arc_reclaim_needed()) {
-			zfs_needfree = 0;
+			needfree = 0;
 #ifdef _KERNEL
-			wakeup(&zfs_needfree);
+			wakeup(&needfree);
 #endif
 		}
 
@@ -1580,6 +1998,9 @@ arc_adapt(int bytes, arc_state_t *state)
 {
 	int mult;
 
+	if (state == arc_l2c_only)
+		return;
+
 	ASSERT(bytes > 0);
 	/*
 	 * Adapt the target size of the MRU list:
@@ -1634,8 +2055,25 @@ arc_adapt(int bytes, arc_state_t *state)
  * prior to insert.
  */
 static int
-arc_evict_needed()
+arc_evict_needed(arc_buf_contents_t type)
 {
+	if (type == ARC_BUFC_METADATA && arc_meta_used >= arc_meta_limit)
+		return (1);
+
+#if 0
+#ifdef _KERNEL
+	/*
+	 * If zio data pages are being allocated out of a separate heap segment,
+	 * then enforce that the size of available vmem for this area remains
+	 * above about 1/32nd free.
+	 */
+	if (type == ARC_BUFC_DATA && zio_arena != NULL &&
+	    vmem_size(zio_arena, VMEM_FREE) <
+	    (vmem_size(zio_arena, VMEM_ALLOC) >> 5))
+		return (1);
+#endif
+#endif
+
 	if (arc_reclaim_needed())
 		return (1);
 
@@ -1678,14 +2116,15 @@ arc_get_data_buf(arc_buf_t *buf)
 	 * We have not yet reached cache maximum size,
 	 * just allocate a new buffer.
 	 */
-	if (!arc_evict_needed()) {
+	if (!arc_evict_needed(type)) {
 		if (type == ARC_BUFC_METADATA) {
 			buf->b_data = zio_buf_alloc(size);
+			arc_space_consume(size);
 		} else {
 			ASSERT(type == ARC_BUFC_DATA);
 			buf->b_data = zio_data_buf_alloc(size);
+			atomic_add_64(&arc_size, size);
 		}
-		atomic_add_64(&arc_size, size);
 		goto out;
 	}
 
@@ -1700,20 +2139,23 @@ arc_get_data_buf(arc_buf_t *buf)
 
 	if (state == arc_mru || state == arc_anon) {
 		uint64_t mru_used = arc_anon->arcs_size + arc_mru->arcs_size;
-		state = (arc_p > mru_used) ? arc_mfu : arc_mru;
+		state = (arc_mfu->arcs_lsize[type] > 0 &&
+		    arc_p > mru_used) ? arc_mfu : arc_mru;
 	} else {
 		/* MFU cases */
 		uint64_t mfu_space = arc_c - arc_p;
-		state =  (mfu_space > arc_mfu->arcs_size) ? arc_mru : arc_mfu;
+		state =  (arc_mru->arcs_lsize[type] > 0 &&
+		    mfu_space > arc_mfu->arcs_size) ? arc_mru : arc_mfu;
 	}
-	if ((buf->b_data = arc_evict(state, size, TRUE, type)) == NULL) {
+	if ((buf->b_data = arc_evict(state, NULL, size, TRUE, type)) == NULL) {
 		if (type == ARC_BUFC_METADATA) {
 			buf->b_data = zio_buf_alloc(size);
+			arc_space_consume(size);
 		} else {
 			ASSERT(type == ARC_BUFC_DATA);
 			buf->b_data = zio_data_buf_alloc(size);
+			atomic_add_64(&arc_size, size);
 		}
-		atomic_add_64(&arc_size, size);
 		ARCSTAT_BUMP(arcstat_recycle_miss);
 	}
 	ASSERT(buf->b_data != NULL);
@@ -1728,7 +2170,7 @@ out:
 		atomic_add_64(&hdr->b_state->arcs_size, size);
 		if (list_link_active(&hdr->b_arc_node)) {
 			ASSERT(refcount_is_zero(&hdr->b_refcnt));
-			atomic_add_64(&hdr->b_state->arcs_lsize, size);
+			atomic_add_64(&hdr->b_state->arcs_lsize[type], size);
 		}
 		/*
 		 * If we are growing the cache, and we are adding anonymous
@@ -1773,10 +2215,6 @@ arc_access(arc_buf_hdr_t *buf, kmutex_t *hash_lock)
 		if ((buf->b_flags & ARC_PREFETCH) != 0) {
 			if (refcount_count(&buf->b_refcnt) == 0) {
 				ASSERT(list_link_active(&buf->b_arc_node));
-				mutex_enter(&arc_mru->arcs_mtx);
-				list_remove(&arc_mru->arcs_list, buf);
-				list_insert_head(&arc_mru->arcs_list, buf);
-				mutex_exit(&arc_mru->arcs_mtx);
 			} else {
 				buf->b_flags &= ~ARC_PREFETCH;
 				ARCSTAT_BUMP(arcstat_mru_hits);
@@ -1836,10 +2274,6 @@ arc_access(arc_buf_hdr_t *buf, kmutex_t *hash_lock)
 		if ((buf->b_flags & ARC_PREFETCH) != 0) {
 			ASSERT(refcount_count(&buf->b_refcnt) == 0);
 			ASSERT(list_link_active(&buf->b_arc_node));
-			mutex_enter(&arc_mfu->arcs_mtx);
-			list_remove(&arc_mfu->arcs_list, buf);
-			list_insert_head(&arc_mfu->arcs_list, buf);
-			mutex_exit(&arc_mfu->arcs_mtx);
 		}
 		ARCSTAT_BUMP(arcstat_mfu_hits);
 		buf->b_arc_access = LBOLT;
@@ -1865,6 +2299,14 @@ arc_access(arc_buf_hdr_t *buf, kmutex_t *hash_lock)
 		arc_change_state(new_state, buf, hash_lock);
 
 		ARCSTAT_BUMP(arcstat_mfu_ghost_hits);
+	} else if (buf->b_state == arc_l2c_only) {
+		/*
+		 * This buffer is on the 2nd Level ARC.
+		 */
+
+		buf->b_arc_access = LBOLT;
+		DTRACE_PROBE1(new_state__mfu, arc_buf_hdr_t *, buf);
+		arc_change_state(arc_mfu, buf, hash_lock);
 	} else {
 		ASSERT(!"invalid arc state");
 	}
@@ -1879,7 +2321,7 @@ arc_bcopy_func(zio_t *zio, arc_buf_t *buf, void *arg)
 	VERIFY(arc_buf_remove_ref(buf, arg) == 1);
 }
 
-/* a generic arc_done_func_t which you can use */
+/* a generic arc_done_func_t */
 void
 arc_getbuf_func(zio_t *zio, arc_buf_t *buf, void *arg)
 {
@@ -1917,15 +2359,24 @@ arc_read_done(zio_t *zio)
 	    &hash_lock);
 
 	ASSERT((found == NULL && HDR_FREED_IN_READ(hdr) && hash_lock == NULL) ||
-	    (found == hdr && DVA_EQUAL(&hdr->b_dva, BP_IDENTITY(zio->io_bp))));
+	    (found == hdr && DVA_EQUAL(&hdr->b_dva, BP_IDENTITY(zio->io_bp))) ||
+	    (found == hdr && HDR_L2_READING(hdr)));
+
+	hdr->b_flags &= ~ARC_L2_EVICTED;
+	if (l2arc_noprefetch && (hdr->b_flags & ARC_PREFETCH))
+		hdr->b_flags &= ~ARC_L2CACHE;
 
 	/* byteswap if necessary */
 	callback_list = hdr->b_acb;
 	ASSERT(callback_list != NULL);
-	if (BP_SHOULD_BYTESWAP(zio->io_bp) && callback_list->acb_byteswap)
-		callback_list->acb_byteswap(buf->b_data, hdr->b_size);
+	if (BP_SHOULD_BYTESWAP(zio->io_bp)) {
+		arc_byteswap_func_t *func = BP_GET_LEVEL(zio->io_bp) > 0 ?
+		    byteswap_uint64_array :
+		    dmu_ot[BP_GET_TYPE(zio->io_bp)].ot_byteswap;
+		func(buf->b_data, hdr->b_size);
+	}
 
-	arc_cksum_compute(buf);
+	arc_cksum_compute(buf, B_FALSE);
 
 	/* create copies of the data buffer for the callers */
 	abuf = buf;
@@ -1952,9 +2403,6 @@ arc_read_done(zio_t *zio)
 		if (HDR_IN_HASH_TABLE(hdr))
 			buf_hash_remove(hdr);
 		freeable = refcount_is_zero(&hdr->b_refcnt);
-		/* convert checksum errors into IO errors */
-		if (zio->io_error == ECKSUM)
-			zio->io_error = EIO;
 	}
 
 	/*
@@ -2020,16 +2468,40 @@ arc_read_done(zio_t *zio)
  *
  * arc_read_done() will invoke all the requested "done" functions
  * for readers of this block.
+ *
+ * Normal callers should use arc_read and pass the arc buffer and offset
+ * for the bp.  But if you know you don't need locking, you can use
+ * arc_read_bp.
  */
 int
-arc_read(zio_t *pio, spa_t *spa, blkptr_t *bp, arc_byteswap_func_t *swap,
-    arc_done_func_t *done, void *private, int priority, int flags,
-    uint32_t *arc_flags, zbookmark_t *zb)
+arc_read(zio_t *pio, spa_t *spa, blkptr_t *bp, arc_buf_t *pbuf,
+    arc_done_func_t *done, void *private, int priority, int zio_flags,
+    uint32_t *arc_flags, const zbookmark_t *zb)
+{
+	int err;
+	arc_buf_hdr_t *hdr = pbuf->b_hdr;
+
+	ASSERT(!refcount_is_zero(&pbuf->b_hdr->b_refcnt));
+	ASSERT3U((char *)bp - (char *)pbuf->b_data, <, pbuf->b_hdr->b_size);
+	rw_enter(&pbuf->b_lock, RW_READER);
+
+	err = arc_read_nolock(pio, spa, bp, done, private, priority,
+	    zio_flags, arc_flags, zb);
+
+	ASSERT3P(hdr, ==, pbuf->b_hdr);
+	rw_exit(&pbuf->b_lock);
+	return (err);
+}
+
+int
+arc_read_nolock(zio_t *pio, spa_t *spa, blkptr_t *bp,
+    arc_done_func_t *done, void *private, int priority, int zio_flags,
+    uint32_t *arc_flags, const zbookmark_t *zb)
 {
 	arc_buf_hdr_t *hdr;
 	arc_buf_t *buf;
 	kmutex_t *hash_lock;
-	zio_t	*rzio;
+	zio_t *rzio;
 
 top:
 	hdr = buf_hash_find(spa, BP_IDENTITY(bp), bp->blk_birth, &hash_lock);
@@ -2053,10 +2525,9 @@ top:
 				    KM_SLEEP);
 				acb->acb_done = done;
 				acb->acb_private = private;
-				acb->acb_byteswap = swap;
 				if (pio != NULL)
 					acb->acb_zio_dummy = zio_null(pio,
-					    spa, NULL, NULL, flags);
+					    spa, NULL, NULL, zio_flags);
 
 				ASSERT(acb->acb_done != NULL);
 				acb->acb_next = hdr->b_acb;
@@ -2093,6 +2564,8 @@ top:
 		}
 		DTRACE_PROBE1(arc__hit, arc_buf_hdr_t *, hdr);
 		arc_access(hdr, hash_lock);
+		if (*arc_flags & ARC_L2CACHE)
+			hdr->b_flags |= ARC_L2CACHE;
 		mutex_exit(hash_lock);
 		ARCSTAT_BUMP(arcstat_hits);
 		ARCSTAT_CONDSTAT(!(hdr->b_flags & ARC_PREFETCH),
@@ -2104,6 +2577,8 @@ top:
 	} else {
 		uint64_t size = BP_GET_LSIZE(bp);
 		arc_callback_t	*acb;
+		vdev_t *vd = NULL;
+		daddr_t addr;
 
 		if (hdr == NULL) {
 			/* this block is not in the cache */
@@ -2130,6 +2605,8 @@ top:
 				    private);
 				hdr->b_flags |= ARC_PREFETCH;
 			}
+			if (*arc_flags & ARC_L2CACHE)
+				hdr->b_flags |= ARC_L2CACHE;
 			if (BP_GET_LEVEL(bp) > 0)
 				hdr->b_flags |= ARC_INDIRECT;
 		} else {
@@ -2144,7 +2621,9 @@ top:
 				hdr->b_flags |= ARC_PREFETCH;
 			else
 				add_reference(hdr, hash_lock, private);
-			buf = kmem_cache_alloc(buf_cache, KM_SLEEP);
+			if (*arc_flags & ARC_L2CACHE)
+				hdr->b_flags |= ARC_L2CACHE;
+			buf = kmem_cache_alloc(buf_cache, KM_PUSHPAGE);
 			buf->b_hdr = hdr;
 			buf->b_data = NULL;
 			buf->b_efunc = NULL;
@@ -2160,7 +2639,6 @@ top:
 		acb = kmem_zalloc(sizeof (arc_callback_t), KM_SLEEP);
 		acb->acb_done = done;
 		acb->acb_private = private;
-		acb->acb_byteswap = swap;
 
 		ASSERT(hdr->b_acb == NULL);
 		hdr->b_acb = acb;
@@ -2176,6 +2654,18 @@ top:
 
 		if (GHOST_STATE(hdr->b_state))
 			arc_access(hdr, hash_lock);
+
+		if (HDR_L2CACHE(hdr) && hdr->b_l2hdr != NULL &&
+		    (vd = hdr->b_l2hdr->b_dev->l2ad_vdev) != NULL) {
+			addr = hdr->b_l2hdr->b_daddr;
+			/*
+			 * Lock out device removal.
+			 */
+			if (vdev_is_dead(vd) ||
+			    !spa_config_tryenter(spa, SCL_L2ARC, vd, RW_READER))
+				vd = NULL;
+		}
+
 		mutex_exit(hash_lock);
 
 		ASSERT3U(hdr->b_size, ==, size);
@@ -2186,8 +2676,65 @@ top:
 		    demand, prefetch, hdr->b_type != ARC_BUFC_METADATA,
 		    data, metadata, misses);
 
+		if (vd != NULL) {
+			/*
+			 * Read from the L2ARC if the following are true:
+			 * 1. The L2ARC vdev was previously cached.
+			 * 2. This buffer still has L2ARC metadata.
+			 * 3. This buffer isn't currently writing to the L2ARC.
+			 * 4. The L2ARC entry wasn't evicted, which may
+			 *    also have invalidated the vdev.
+			 */
+			if (hdr->b_l2hdr != NULL &&
+			    !HDR_L2_WRITING(hdr) && !HDR_L2_EVICTED(hdr)) {
+				l2arc_read_callback_t *cb;
+
+				DTRACE_PROBE1(l2arc__hit, arc_buf_hdr_t *, hdr);
+				ARCSTAT_BUMP(arcstat_l2_hits);
+
+				cb = kmem_zalloc(sizeof (l2arc_read_callback_t),
+				    KM_SLEEP);
+				cb->l2rcb_buf = buf;
+				cb->l2rcb_spa = spa;
+				cb->l2rcb_bp = *bp;
+				cb->l2rcb_zb = *zb;
+				cb->l2rcb_flags = zio_flags;
+
+				/*
+				 * l2arc read.  The SCL_L2ARC lock will be
+				 * released by l2arc_read_done().
+				 */
+				rzio = zio_read_phys(pio, vd, addr, size,
+				    buf->b_data, ZIO_CHECKSUM_OFF, 
+				    l2arc_read_done, cb, priority, zio_flags |
+				    ZIO_FLAG_DONT_CACHE | ZIO_FLAG_CANFAIL |
+				    ZIO_FLAG_DONT_PROPAGATE |
+				    ZIO_FLAG_DONT_RETRY, B_FALSE);
+				DTRACE_PROBE2(l2arc__read, vdev_t *, vd,
+				    zio_t *, rzio);
+
+				if (*arc_flags & ARC_NOWAIT) {
+					zio_nowait(rzio);
+					return (0);
+				}
+
+				ASSERT(*arc_flags & ARC_WAIT);
+				if (zio_wait(rzio) == 0)
+					return (0);
+
+				/* l2arc read error; goto zio_read() */
+			} else {
+				DTRACE_PROBE1(l2arc__miss,
+				    arc_buf_hdr_t *, hdr);
+				ARCSTAT_BUMP(arcstat_l2_misses);
+				if (HDR_L2_WRITING(hdr))
+					ARCSTAT_BUMP(arcstat_l2_rw_clash);
+				spa_config_exit(spa, SCL_L2ARC, vd);
+			}
+		}
+
 		rzio = zio_read(pio, spa, bp, buf->b_data, size,
-		    arc_read_done, buf, priority, flags, zb);
+		    arc_read_done, buf, priority, zio_flags, zb);
 
 		if (*arc_flags & ARC_WAIT)
 			return (zio_wait(rzio));
@@ -2254,45 +2801,28 @@ arc_buf_evict(arc_buf_t *buf)
 	kmutex_t *hash_lock;
 	arc_buf_t **bufp;
 
-	mutex_enter(&arc_eviction_mtx);
+	rw_enter(&buf->b_lock, RW_WRITER);
 	hdr = buf->b_hdr;
 	if (hdr == NULL) {
 		/*
 		 * We are in arc_do_user_evicts().
 		 */
 		ASSERT(buf->b_data == NULL);
-		mutex_exit(&arc_eviction_mtx);
+		rw_exit(&buf->b_lock);
 		return (0);
-	}
-	hash_lock = HDR_LOCK(hdr);
-	mutex_exit(&arc_eviction_mtx);
-
-	mutex_enter(hash_lock);
-
-	if (buf->b_data == NULL) {
+	} else if (buf->b_data == NULL) {
+		arc_buf_t copy = *buf; /* structure assignment */
 		/*
-		 * We are on the eviction list.
+		 * We are on the eviction list; process this buffer now
+		 * but let arc_do_user_evicts() do the reaping.
 		 */
-		mutex_exit(hash_lock);
-		mutex_enter(&arc_eviction_mtx);
-		if (buf->b_hdr == NULL) {
-			/*
-			 * We are already in arc_do_user_evicts().
-			 */
-			mutex_exit(&arc_eviction_mtx);
-			return (0);
-		} else {
-			arc_buf_t copy = *buf; /* structure assignment */
-			/*
-			 * Process this buffer now
-			 * but let arc_do_user_evicts() do the reaping.
-			 */
-			buf->b_efunc = NULL;
-			mutex_exit(&arc_eviction_mtx);
-			VERIFY(copy.b_efunc(&copy) == 0);
-			return (1);
-		}
+		buf->b_efunc = NULL;
+		rw_exit(&buf->b_lock);
+		VERIFY(copy.b_efunc(&copy) == 0);
+		return (1);
 	}
+	hash_lock = HDR_LOCK(hdr);
+	mutex_enter(hash_lock);
 
 	ASSERT(buf->b_hdr == hdr);
 	ASSERT3U(refcount_count(&hdr->b_refcnt), <, hdr->b_datacnt);
@@ -2323,12 +2853,14 @@ arc_buf_evict(arc_buf_t *buf)
 
 		arc_change_state(evicted_state, hdr, hash_lock);
 		ASSERT(HDR_IN_HASH_TABLE(hdr));
-		hdr->b_flags = ARC_IN_HASH_TABLE;
+		hdr->b_flags |= ARC_IN_HASH_TABLE;
+		hdr->b_flags &= ~ARC_BUF_AVAILABLE;
 
 		mutex_exit(&evicted_state->arcs_mtx);
 		mutex_exit(&old_state->arcs_mtx);
 	}
 	mutex_exit(hash_lock);
+	rw_exit(&buf->b_lock);
 
 	VERIFY(buf->b_efunc(buf) == 0);
 	buf->b_efunc = NULL;
@@ -2342,16 +2874,22 @@ arc_buf_evict(arc_buf_t *buf)
  * Release this buffer from the cache.  This must be done
  * after a read and prior to modifying the buffer contents.
  * If the buffer has more than one reference, we must make
- * make a new hdr for the buffer.
+ * a new hdr for the buffer.
  */
 void
 arc_release(arc_buf_t *buf, void *tag)
 {
-	arc_buf_hdr_t *hdr = buf->b_hdr;
-	kmutex_t *hash_lock = HDR_LOCK(hdr);
+	arc_buf_hdr_t *hdr;
+	kmutex_t *hash_lock;
+	l2arc_buf_hdr_t *l2hdr;
+	uint64_t buf_size;
+
+	rw_enter(&buf->b_lock, RW_WRITER);
+	hdr = buf->b_hdr;
 
 	/* this buffer is not on any list */
 	ASSERT(refcount_count(&hdr->b_refcnt) > 0);
+	ASSERT(!(hdr->b_flags & ARC_STORED));
 
 	if (hdr->b_state == arc_anon) {
 		/* this buffer is already released */
@@ -2359,22 +2897,32 @@ arc_release(arc_buf_t *buf, void *tag)
 		ASSERT(BUF_EMPTY(hdr));
 		ASSERT(buf->b_efunc == NULL);
 		arc_buf_thaw(buf);
+		rw_exit(&buf->b_lock);
 		return;
 	}
 
+	hash_lock = HDR_LOCK(hdr);
 	mutex_enter(hash_lock);
 
+	l2hdr = hdr->b_l2hdr;
+	if (l2hdr) {
+		mutex_enter(&l2arc_buflist_mtx);
+		hdr->b_l2hdr = NULL;
+		buf_size = hdr->b_size;
+	}
+
 	/*
 	 * Do we have more than one buf?
 	 */
-	if (hdr->b_buf != buf || buf->b_next != NULL) {
+	if (hdr->b_datacnt > 1) {
 		arc_buf_hdr_t *nhdr;
 		arc_buf_t **bufp;
 		uint64_t blksz = hdr->b_size;
 		spa_t *spa = hdr->b_spa;
 		arc_buf_contents_t type = hdr->b_type;
+		uint32_t flags = hdr->b_flags;
 
-		ASSERT(hdr->b_datacnt > 1);
+		ASSERT(hdr->b_buf != buf || buf->b_next != NULL);
 		/*
 		 * Pull the data off of this buf and attach it to
 		 * a new anonymous buf.
@@ -2389,37 +2937,39 @@ arc_release(arc_buf_t *buf, void *tag)
 		ASSERT3U(hdr->b_state->arcs_size, >=, hdr->b_size);
 		atomic_add_64(&hdr->b_state->arcs_size, -hdr->b_size);
 		if (refcount_is_zero(&hdr->b_refcnt)) {
-			ASSERT3U(hdr->b_state->arcs_lsize, >=, hdr->b_size);
-			atomic_add_64(&hdr->b_state->arcs_lsize, -hdr->b_size);
+			uint64_t *size = &hdr->b_state->arcs_lsize[hdr->b_type];
+			ASSERT3U(*size, >=, hdr->b_size);
+			atomic_add_64(size, -hdr->b_size);
 		}
 		hdr->b_datacnt -= 1;
 		arc_cksum_verify(buf);
 
 		mutex_exit(hash_lock);
 
-		nhdr = kmem_cache_alloc(hdr_cache, KM_SLEEP);
+		nhdr = kmem_cache_alloc(hdr_cache, KM_PUSHPAGE);
 		nhdr->b_size = blksz;
 		nhdr->b_spa = spa;
 		nhdr->b_type = type;
 		nhdr->b_buf = buf;
 		nhdr->b_state = arc_anon;
 		nhdr->b_arc_access = 0;
-		nhdr->b_flags = 0;
+		nhdr->b_flags = flags & ARC_L2_WRITING;
+		nhdr->b_l2hdr = NULL;
 		nhdr->b_datacnt = 1;
 		nhdr->b_freeze_cksum = NULL;
-		mutex_init(&nhdr->b_freeze_lock, NULL, MUTEX_DEFAULT, NULL);
 		(void) refcount_add(&nhdr->b_refcnt, tag);
 		buf->b_hdr = nhdr;
+		rw_exit(&buf->b_lock);
 		atomic_add_64(&arc_anon->arcs_size, blksz);
-
-		hdr = nhdr;
 	} else {
+		rw_exit(&buf->b_lock);
 		ASSERT(refcount_count(&hdr->b_refcnt) == 1);
 		ASSERT(!list_link_active(&hdr->b_arc_node));
 		ASSERT(!HDR_IO_IN_PROGRESS(hdr));
 		arc_change_state(arc_anon, hdr, hash_lock);
 		hdr->b_arc_access = 0;
 		mutex_exit(hash_lock);
+
 		bzero(&hdr->b_dva, sizeof (dva_t));
 		hdr->b_birth = 0;
 		hdr->b_cksum0 = 0;
@@ -2427,25 +2977,47 @@ arc_release(arc_buf_t *buf, void *tag)
 	}
 	buf->b_efunc = NULL;
 	buf->b_private = NULL;
+
+	if (l2hdr) {
+		list_remove(l2hdr->b_dev->l2ad_buflist, hdr);
+		kmem_free(l2hdr, sizeof (l2arc_buf_hdr_t));
+		ARCSTAT_INCR(arcstat_l2_size, -buf_size);
+		mutex_exit(&l2arc_buflist_mtx);
+	}
 }
 
 int
 arc_released(arc_buf_t *buf)
 {
-	return (buf->b_data != NULL && buf->b_hdr->b_state == arc_anon);
+	int released;
+
+	rw_enter(&buf->b_lock, RW_READER);
+	released = (buf->b_data != NULL && buf->b_hdr->b_state == arc_anon);
+	rw_exit(&buf->b_lock);
+	return (released);
 }
 
 int
 arc_has_callback(arc_buf_t *buf)
 {
-	return (buf->b_efunc != NULL);
+	int callback;
+
+	rw_enter(&buf->b_lock, RW_READER);
+	callback = (buf->b_efunc != NULL);
+	rw_exit(&buf->b_lock);
+	return (callback);
 }
 
 #ifdef ZFS_DEBUG
 int
 arc_referenced(arc_buf_t *buf)
 {
-	return (refcount_count(&buf->b_hdr->b_refcnt));
+	int referenced;
+
+	rw_enter(&buf->b_lock, RW_READER);
+	referenced = (refcount_count(&buf->b_hdr->b_refcnt));
+	rw_exit(&buf->b_lock);
+	return (referenced);
 }
 #endif
 
@@ -2454,12 +3026,27 @@ arc_write_ready(zio_t *zio)
 {
 	arc_write_callback_t *callback = zio->io_private;
 	arc_buf_t *buf = callback->awcb_buf;
+	arc_buf_hdr_t *hdr = buf->b_hdr;
 
-	if (callback->awcb_ready) {
-		ASSERT(!refcount_is_zero(&buf->b_hdr->b_refcnt));
-		callback->awcb_ready(zio, buf, callback->awcb_private);
+	ASSERT(!refcount_is_zero(&buf->b_hdr->b_refcnt));
+	callback->awcb_ready(zio, buf, callback->awcb_private);
+
+	/*
+	 * If the IO is already in progress, then this is a re-write
+	 * attempt, so we need to thaw and re-compute the cksum.
+	 * It is the responsibility of the callback to handle the
+	 * accounting for any re-write attempt.
+	 */
+	if (HDR_IO_IN_PROGRESS(hdr)) {
+		mutex_enter(&hdr->b_freeze_lock);
+		if (hdr->b_freeze_cksum != NULL) {
+			kmem_free(hdr->b_freeze_cksum, sizeof (zio_cksum_t));
+			hdr->b_freeze_cksum = NULL;
+		}
+		mutex_exit(&hdr->b_freeze_lock);
 	}
-	arc_cksum_compute(buf);
+	arc_cksum_compute(buf, B_FALSE);
+	hdr->b_flags |= ARC_IO_IN_PROGRESS;
 }
 
 static void
@@ -2471,9 +3058,6 @@ arc_write_done(zio_t *zio)
 
 	hdr->b_acb = NULL;
 
-	/* this buffer is on no lists and is not in the hash table */
-	ASSERT3P(hdr->b_state, ==, arc_anon);
-
 	hdr->b_dva = *BP_IDENTITY(zio->io_bp);
 	hdr->b_birth = zio->io_bp->blk_birth;
 	hdr->b_cksum0 = zio->io_bp->blk_cksum.zc_word[0];
@@ -2496,6 +3080,7 @@ arc_write_done(zio_t *zio)
 			 * sync-to-convergence, because we remove
 			 * buffers from the hash table when we arc_free().
 			 */
+			ASSERT(zio->io_flags & ZIO_FLAG_IO_REWRITE);
 			ASSERT(DVA_EQUAL(BP_IDENTITY(&zio->io_bp_orig),
 			    BP_IDENTITY(zio->io_bp)));
 			ASSERT3U(zio->io_bp_orig.blk_birth, ==,
@@ -2509,7 +3094,9 @@ arc_write_done(zio_t *zio)
 			ASSERT3P(exists, ==, NULL);
 		}
 		hdr->b_flags &= ~ARC_IO_IN_PROGRESS;
-		arc_access(hdr, hash_lock);
+		/* if it's not anon, we are doing a scrub */
+		if (hdr->b_state == arc_anon)
+			arc_access(hdr, hash_lock);
 		mutex_exit(hash_lock);
 	} else if (callback->awcb_done == NULL) {
 		int destroy_hdr;
@@ -2526,6 +3113,7 @@ arc_write_done(zio_t *zio)
 	} else {
 		hdr->b_flags &= ~ARC_IO_IN_PROGRESS;
 	}
+	hdr->b_flags &= ~ARC_STORED;
 
 	if (callback->awcb_done) {
 		ASSERT(!refcount_is_zero(&hdr->b_refcnt));
@@ -2535,31 +3123,74 @@ arc_write_done(zio_t *zio)
 	kmem_free(callback, sizeof (arc_write_callback_t));
 }
 
+static void
+write_policy(spa_t *spa, const writeprops_t *wp, zio_prop_t *zp)
+{
+	boolean_t ismd = (wp->wp_level > 0 || dmu_ot[wp->wp_type].ot_metadata);
+
+	/* Determine checksum setting */
+	if (ismd) {
+		/*
+		 * Metadata always gets checksummed.  If the data
+		 * checksum is multi-bit correctable, and it's not a
+		 * ZBT-style checksum, then it's suitable for metadata
+		 * as well.  Otherwise, the metadata checksum defaults
+		 * to fletcher4.
+		 */
+		if (zio_checksum_table[wp->wp_oschecksum].ci_correctable &&
+		    !zio_checksum_table[wp->wp_oschecksum].ci_zbt)
+			zp->zp_checksum = wp->wp_oschecksum;
+		else
+			zp->zp_checksum = ZIO_CHECKSUM_FLETCHER_4;
+	} else {
+		zp->zp_checksum = zio_checksum_select(wp->wp_dnchecksum,
+		    wp->wp_oschecksum);
+	}
+
+	/* Determine compression setting */
+	if (ismd) {
+		/*
+		 * XXX -- we should design a compression algorithm
+		 * that specializes in arrays of bps.
+		 */
+		zp->zp_compress = zfs_mdcomp_disable ? ZIO_COMPRESS_EMPTY :
+		    ZIO_COMPRESS_LZJB;
+	} else {
+		zp->zp_compress = zio_compress_select(wp->wp_dncompress,
+		    wp->wp_oscompress);
+	}
+
+	zp->zp_type = wp->wp_type;
+	zp->zp_level = wp->wp_level;
+	zp->zp_ndvas = MIN(wp->wp_copies + ismd, spa_max_replication(spa));
+}
+
 zio_t *
-arc_write(zio_t *pio, spa_t *spa, int checksum, int compress, int ncopies,
-    uint64_t txg, blkptr_t *bp, arc_buf_t *buf,
+arc_write(zio_t *pio, spa_t *spa, const writeprops_t *wp,
+    boolean_t l2arc, uint64_t txg, blkptr_t *bp, arc_buf_t *buf,
     arc_done_func_t *ready, arc_done_func_t *done, void *private, int priority,
-    int flags, zbookmark_t *zb)
+    int zio_flags, const zbookmark_t *zb)
 {
 	arc_buf_hdr_t *hdr = buf->b_hdr;
 	arc_write_callback_t *callback;
-	zio_t	*zio;
+	zio_t *zio;
+	zio_prop_t zp;
 
-	/* this is a private buffer - no locking required */
-	ASSERT3P(hdr->b_state, ==, arc_anon);
-	ASSERT(BUF_EMPTY(hdr));
+	ASSERT(ready != NULL);
 	ASSERT(!HDR_IO_ERROR(hdr));
 	ASSERT((hdr->b_flags & ARC_IO_IN_PROGRESS) == 0);
 	ASSERT(hdr->b_acb == 0);
+	if (l2arc)
+		hdr->b_flags |= ARC_L2CACHE;
 	callback = kmem_zalloc(sizeof (arc_write_callback_t), KM_SLEEP);
 	callback->awcb_ready = ready;
 	callback->awcb_done = done;
 	callback->awcb_private = private;
 	callback->awcb_buf = buf;
-	hdr->b_flags |= ARC_IO_IN_PROGRESS;
-	zio = zio_write(pio, spa, checksum, compress, ncopies, txg, bp,
-	    buf->b_data, hdr->b_size, arc_write_ready, arc_write_done, callback,
-	    priority, flags, zb);
+
+	write_policy(spa, wp, &zp);
+	zio = zio_write(pio, spa, txg, bp, buf->b_data, hdr->b_size, &zp,
+	    arc_write_ready, arc_write_done, callback, priority, zio_flags, zb);
 
 	return (zio);
 }
@@ -2584,7 +3215,9 @@ arc_free(zio_t *pio, spa_t *spa, uint64_t txg, blkptr_t *bp,
 		 * nonzero, it should match what we have in the cache.
 		 */
 		ASSERT(bp->blk_cksum.zc_word[0] == 0 ||
-		    ab->b_cksum0 == bp->blk_cksum.zc_word[0]);
+		    bp->blk_cksum.zc_word[0] == ab->b_cksum0 ||
+		    bp->blk_fill == BLK_FILL_ALREADY_FREED);
+
 		if (ab->b_state != arc_anon)
 			arc_change_state(arc_anon, ab, hash_lock);
 		if (HDR_IO_IN_PROGRESS(ab)) {
@@ -2604,6 +3237,7 @@ arc_free(zio_t *pio, spa_t *spa, uint64_t txg, blkptr_t *bp,
 			ab->b_buf->b_private = NULL;
 			mutex_exit(hash_lock);
 		} else if (refcount_is_zero(&ab->b_refcnt)) {
+			ab->b_flags |= ARC_FREE_IN_PROGRESS;
 			mutex_exit(hash_lock);
 			arc_hdr_destroy(ab);
 			ARCSTAT_BUMP(arcstat_deleted);
@@ -2624,7 +3258,7 @@ arc_free(zio_t *pio, spa_t *spa, uint64_t txg, blkptr_t *bp,
 		}
 	}
 
-	zio = zio_free(pio, spa, txg, bp, done, private);
+	zio = zio_free(pio, spa, txg, bp, done, private, ZIO_FLAG_MUSTSUCCEED);
 
 	if (arc_flags & ARC_WAIT)
 		return (zio_wait(zio));
@@ -2635,16 +3269,75 @@ arc_free(zio_t *pio, spa_t *spa, uint64_t txg, blkptr_t *bp,
 	return (0);
 }
 
+static int
+arc_memory_throttle(uint64_t reserve, uint64_t txg)
+{
+#ifdef _KERNEL
+	uint64_t inflight_data = arc_anon->arcs_size;
+	uint64_t available_memory = ptoa((uintmax_t)cnt.v_free_count);
+	static uint64_t page_load = 0;
+	static uint64_t last_txg = 0;
+
+#if 0
+#if defined(__i386)
+	available_memory =
+	    MIN(available_memory, vmem_size(heap_arena, VMEM_FREE));
+#endif
+#endif
+	if (available_memory >= zfs_write_limit_max)
+		return (0);
+
+	if (txg > last_txg) {
+		last_txg = txg;
+		page_load = 0;
+	}
+	/*
+	 * If we are in pageout, we know that memory is already tight,
+	 * the arc is already going to be evicting, so we just want to
+	 * continue to let page writes occur as quickly as possible.
+	 */
+	if (curproc == pageproc) {
+		if (page_load > available_memory / 4)
+			return (ERESTART);
+		/* Note: reserve is inflated, so we deflate */
+		page_load += reserve / 8;
+		return (0);
+	} else if (page_load > 0 && arc_reclaim_needed()) {
+		/* memory is low, delay before restarting */
+		ARCSTAT_INCR(arcstat_memory_throttle_count, 1);
+		return (EAGAIN);
+	}
+	page_load = 0;
+
+	if (arc_size > arc_c_min) {
+		uint64_t evictable_memory =
+		    arc_mru->arcs_lsize[ARC_BUFC_DATA] +
+		    arc_mru->arcs_lsize[ARC_BUFC_METADATA] +
+		    arc_mfu->arcs_lsize[ARC_BUFC_DATA] +
+		    arc_mfu->arcs_lsize[ARC_BUFC_METADATA];
+		available_memory += MIN(evictable_memory, arc_size - arc_c_min);
+	}
+
+	if (inflight_data > available_memory / 4) {
+		ARCSTAT_INCR(arcstat_memory_throttle_count, 1);
+		return (ERESTART);
+	}
+#endif
+	return (0);
+}
+
 void
-arc_tempreserve_clear(uint64_t tempreserve)
+arc_tempreserve_clear(uint64_t reserve)
 {
-	atomic_add_64(&arc_tempreserve, -tempreserve);
+	atomic_add_64(&arc_tempreserve, -reserve);
 	ASSERT((int64_t)arc_tempreserve >= 0);
 }
 
 int
-arc_tempreserve_space(uint64_t tempreserve)
+arc_tempreserve_space(uint64_t reserve, uint64_t txg)
 {
+	int error;
+
 #ifdef ZFS_DEBUG
 	/*
 	 * Once in a while, fail for no reason.  Everything should cope.
@@ -2654,31 +3347,37 @@ arc_tempreserve_space(uint64_t tempreserve)
 		return (ERESTART);
 	}
 #endif
-	if (tempreserve > arc_c/4 && !arc_no_grow)
-		arc_c = MIN(arc_c_max, tempreserve * 4);
-	if (tempreserve > arc_c)
+	if (reserve > arc_c/4 && !arc_no_grow)
+		arc_c = MIN(arc_c_max, reserve * 4);
+	if (reserve > arc_c)
 		return (ENOMEM);
 
 	/*
+	 * Writes will, almost always, require additional memory allocations
+	 * in order to compress/encrypt/etc the data.  We therefor need to
+	 * make sure that there is sufficient available memory for this.
+	 */
+	if (error = arc_memory_throttle(reserve, txg))
+		return (error);
+
+	/*
 	 * Throttle writes when the amount of dirty data in the cache
 	 * gets too large.  We try to keep the cache less than half full
 	 * of dirty blocks so that our sync times don't grow too large.
 	 * Note: if two requests come in concurrently, we might let them
 	 * both succeed, when one of them should fail.  Not a huge deal.
-	 *
-	 * XXX The limit should be adjusted dynamically to keep the time
-	 * to sync a dataset fixed (around 1-5 seconds?).
 	 */
-
-	if (tempreserve + arc_tempreserve + arc_anon->arcs_size > arc_c / 2 &&
-	    arc_tempreserve + arc_anon->arcs_size > arc_c / 4) {
-		dprintf("failing, arc_tempreserve=%lluK anon=%lluK "
-		    "tempreserve=%lluK arc_c=%lluK\n",
-		    arc_tempreserve>>10, arc_anon->arcs_lsize>>10,
-		    tempreserve>>10, arc_c>>10);
+	if (reserve + arc_tempreserve + arc_anon->arcs_size > arc_c / 2 &&
+	    arc_anon->arcs_size > arc_c / 4) {
+		dprintf("failing, arc_tempreserve=%lluK anon_meta=%lluK "
+		    "anon_data=%lluK tempreserve=%lluK arc_c=%lluK\n",
+		    arc_tempreserve>>10,
+		    arc_anon->arcs_lsize[ARC_BUFC_METADATA]>>10,
+		    arc_anon->arcs_lsize[ARC_BUFC_DATA]>>10,
+		    reserve>>10, arc_c>>10);
 		return (ERESTART);
 	}
-	atomic_add_64(&arc_tempreserve, tempreserve);
+	atomic_add_64(&arc_tempreserve, reserve);
 	return (0);
 }
 
@@ -2692,10 +3391,10 @@ arc_lowmem(void *arg __unused, int howto __unused)
 
 	/* Serialize access via arc_lowmem_lock. */
 	mutex_enter(&arc_lowmem_lock);
-	zfs_needfree = 1;
+	needfree = 1;
 	cv_signal(&arc_reclaim_thr_cv);
-	while (zfs_needfree)
-		tsleep(&zfs_needfree, 0, "zfs:lowmem", hz / 5);
+	while (needfree)
+		tsleep(&needfree, 0, "zfs:lowmem", hz / 5);
 	mutex_exit(&arc_lowmem_lock);
 }
 #endif
@@ -2743,6 +3442,16 @@ arc_init(void)
 	arc_c = arc_c_max;
 	arc_p = (arc_c >> 1);
 
+	/* limit meta-data to 1/4 of the arc capacity */
+	arc_meta_limit = arc_c_max / 4;
+
+	/* Allow the tunable to override if it is reasonable */
+	if (zfs_arc_meta_limit > 0 && zfs_arc_meta_limit <= arc_c_max)
+		arc_meta_limit = zfs_arc_meta_limit;
+
+	if (arc_c_min < arc_meta_limit / 2 && zfs_arc_min == 0)
+		arc_c_min = arc_meta_limit / 2;
+
 	/* if kmem_flags are set, lets try to use less memory */
 	if (kmem_debugging())
 		arc_c = arc_c / 2;
@@ -2757,6 +3466,7 @@ arc_init(void)
 	arc_mru_ghost = &ARC_mru_ghost;
 	arc_mfu = &ARC_mfu;
 	arc_mfu_ghost = &ARC_mfu_ghost;
+	arc_l2c_only = &ARC_l2c_only;
 	arc_size = 0;
 
 	mutex_init(&arc_anon->arcs_mtx, NULL, MUTEX_DEFAULT, NULL);
@@ -2764,15 +3474,28 @@ arc_init(void)
 	mutex_init(&arc_mru_ghost->arcs_mtx, NULL, MUTEX_DEFAULT, NULL);
 	mutex_init(&arc_mfu->arcs_mtx, NULL, MUTEX_DEFAULT, NULL);
 	mutex_init(&arc_mfu_ghost->arcs_mtx, NULL, MUTEX_DEFAULT, NULL);
-
-	list_create(&arc_mru->arcs_list, sizeof (arc_buf_hdr_t),
-	    offsetof(arc_buf_hdr_t, b_arc_node));
-	list_create(&arc_mru_ghost->arcs_list, sizeof (arc_buf_hdr_t),
-	    offsetof(arc_buf_hdr_t, b_arc_node));
-	list_create(&arc_mfu->arcs_list, sizeof (arc_buf_hdr_t),
-	    offsetof(arc_buf_hdr_t, b_arc_node));
-	list_create(&arc_mfu_ghost->arcs_list, sizeof (arc_buf_hdr_t),
-	    offsetof(arc_buf_hdr_t, b_arc_node));
+	mutex_init(&arc_l2c_only->arcs_mtx, NULL, MUTEX_DEFAULT, NULL);
+
+	list_create(&arc_mru->arcs_list[ARC_BUFC_METADATA],
+	    sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node));
+	list_create(&arc_mru->arcs_list[ARC_BUFC_DATA],
+	    sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node));
+	list_create(&arc_mru_ghost->arcs_list[ARC_BUFC_METADATA],
+	    sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node));
+	list_create(&arc_mru_ghost->arcs_list[ARC_BUFC_DATA],
+	    sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node));
+	list_create(&arc_mfu->arcs_list[ARC_BUFC_METADATA],
+	    sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node));
+	list_create(&arc_mfu->arcs_list[ARC_BUFC_DATA],
+	    sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node));
+	list_create(&arc_mfu_ghost->arcs_list[ARC_BUFC_METADATA],
+	    sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node));
+	list_create(&arc_mfu_ghost->arcs_list[ARC_BUFC_DATA],
+	    sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node));
+	list_create(&arc_l2c_only->arcs_list[ARC_BUFC_METADATA],
+	    sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node));
+	list_create(&arc_l2c_only->arcs_list[ARC_BUFC_DATA],
+	    sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node));
 
 	buf_init();
 
@@ -2798,6 +3521,13 @@ arc_init(void)
 #endif
 
 	arc_dead = FALSE;
+	arc_warm = B_FALSE;
+
+	if (zfs_write_limit_max == 0)
+		zfs_write_limit_max = ptob(physmem) >> zfs_write_limit_shift;
+	else
+		zfs_write_limit_shift = 0;
+	mutex_init(&zfs_write_limit_lock, NULL, MUTEX_DEFAULT, NULL);
 
 #ifdef _KERNEL
 	/* Warn about ZFS memory and address space requirements. */
@@ -2808,9 +3538,9 @@ arc_init(void)
 	if (kmem_size() < 512 * (1 << 20)) {
 		printf("ZFS WARNING: Recommended minimum kmem_size is 512MB; "
 		    "expect unstable behavior.\n");
-		printf("	     Consider tuning vm.kmem_size and "
+		printf("             Consider tuning vm.kmem_size and "
 		    "vm.kmem_size_max\n");
-		printf("	     in /boot/loader.conf.\n");
+		printf("             in /boot/loader.conf.\n");
 	}
 #endif
 }
@@ -2818,6 +3548,7 @@ arc_init(void)
 void
 arc_fini(void)
 {
+
 	mutex_enter(&arc_reclaim_thr_lock);
 	arc_thread_exit = 1;
 	cv_signal(&arc_reclaim_thr_cv);
@@ -2825,7 +3556,7 @@ arc_fini(void)
 		cv_wait(&arc_reclaim_thr_cv, &arc_reclaim_thr_lock);
 	mutex_exit(&arc_reclaim_thr_lock);
 
-	arc_flush();
+	arc_flush(NULL);
 
 	arc_dead = TRUE;
 
@@ -2838,10 +3569,14 @@ arc_fini(void)
 	mutex_destroy(&arc_reclaim_thr_lock);
 	cv_destroy(&arc_reclaim_thr_cv);
 
-	list_destroy(&arc_mru->arcs_list);
-	list_destroy(&arc_mru_ghost->arcs_list);
-	list_destroy(&arc_mfu->arcs_list);
-	list_destroy(&arc_mfu_ghost->arcs_list);
+	list_destroy(&arc_mru->arcs_list[ARC_BUFC_METADATA]);
+	list_destroy(&arc_mru_ghost->arcs_list[ARC_BUFC_METADATA]);
+	list_destroy(&arc_mfu->arcs_list[ARC_BUFC_METADATA]);
+	list_destroy(&arc_mfu_ghost->arcs_list[ARC_BUFC_METADATA]);
+	list_destroy(&arc_mru->arcs_list[ARC_BUFC_DATA]);
+	list_destroy(&arc_mru_ghost->arcs_list[ARC_BUFC_DATA]);
+	list_destroy(&arc_mfu->arcs_list[ARC_BUFC_DATA]);
+	list_destroy(&arc_mfu_ghost->arcs_list[ARC_BUFC_DATA]);
 
 	mutex_destroy(&arc_anon->arcs_mtx);
 	mutex_destroy(&arc_mru->arcs_mtx);
@@ -2849,6 +3584,8 @@ arc_fini(void)
 	mutex_destroy(&arc_mfu->arcs_mtx);
 	mutex_destroy(&arc_mfu_ghost->arcs_mtx);
 
+	mutex_destroy(&zfs_write_limit_lock);
+
 	buf_fini();
 
 	mutex_destroy(&arc_lowmem_lock);
@@ -2857,3 +3594,985 @@ arc_fini(void)
 		EVENTHANDLER_DEREGISTER(vm_lowmem, arc_event_lowmem);
 #endif
 }
+
+/*
+ * Level 2 ARC
+ *
+ * The level 2 ARC (L2ARC) is a cache layer in-between main memory and disk.
+ * It uses dedicated storage devices to hold cached data, which are populated
+ * using large infrequent writes.  The main role of this cache is to boost
+ * the performance of random read workloads.  The intended L2ARC devices
+ * include short-stroked disks, solid state disks, and other media with
+ * substantially faster read latency than disk.
+ *
+ *                 +-----------------------+
+ *                 |         ARC           |
+ *                 +-----------------------+
+ *                    |         ^     ^
+ *                    |         |     |
+ *      l2arc_feed_thread()    arc_read()
+ *                    |         |     |
+ *                    |  l2arc read   |
+ *                    V         |     |
+ *               +---------------+    |
+ *               |     L2ARC     |    |
+ *               +---------------+    |
+ *                   |    ^           |
+ *          l2arc_write() |           |
+ *                   |    |           |
+ *                   V    |           |
+ *                 +-------+      +-------+
+ *                 | vdev  |      | vdev  |
+ *                 | cache |      | cache |
+ *                 +-------+      +-------+
+ *                 +=========+     .-----.
+ *                 :  L2ARC  :    |-_____-|
+ *                 : devices :    | Disks |
+ *                 +=========+    `-_____-'
+ *
+ * Read requests are satisfied from the following sources, in order:
+ *
+ *	1) ARC
+ *	2) vdev cache of L2ARC devices
+ *	3) L2ARC devices
+ *	4) vdev cache of disks
+ *	5) disks
+ *
+ * Some L2ARC device types exhibit extremely slow write performance.
+ * To accommodate for this there are some significant differences between
+ * the L2ARC and traditional cache design:
+ *
+ * 1. There is no eviction path from the ARC to the L2ARC.  Evictions from
+ * the ARC behave as usual, freeing buffers and placing headers on ghost
+ * lists.  The ARC does not send buffers to the L2ARC during eviction as
+ * this would add inflated write latencies for all ARC memory pressure.
+ *
+ * 2. The L2ARC attempts to cache data from the ARC before it is evicted.
+ * It does this by periodically scanning buffers from the eviction-end of
+ * the MFU and MRU ARC lists, copying them to the L2ARC devices if they are
+ * not already there.  It scans until a headroom of buffers is satisfied,
+ * which itself is a buffer for ARC eviction.  The thread that does this is
+ * l2arc_feed_thread(), illustrated below; example sizes are included to
+ * provide a better sense of ratio than this diagram:
+ *
+ *	       head -->                        tail
+ *	        +---------------------+----------+
+ *	ARC_mfu |:::::#:::::::::::::::|o#o###o###|-->.   # already on L2ARC
+ *	        +---------------------+----------+   |   o L2ARC eligible
+ *	ARC_mru |:#:::::::::::::::::::|#o#ooo####|-->|   : ARC buffer
+ *	        +---------------------+----------+   |
+ *	             15.9 Gbytes      ^ 32 Mbytes    |
+ *	                           headroom          |
+ *	                                      l2arc_feed_thread()
+ *	                                             |
+ *	                 l2arc write hand <--[oooo]--'
+ *	                         |           8 Mbyte
+ *	                         |          write max
+ *	                         V
+ *		  +==============================+
+ *	L2ARC dev |####|#|###|###|    |####| ... |
+ *	          +==============================+
+ *	                     32 Gbytes
+ *
+ * 3. If an ARC buffer is copied to the L2ARC but then hit instead of
+ * evicted, then the L2ARC has cached a buffer much sooner than it probably
+ * needed to, potentially wasting L2ARC device bandwidth and storage.  It is
+ * safe to say that this is an uncommon case, since buffers at the end of
+ * the ARC lists have moved there due to inactivity.
+ *
+ * 4. If the ARC evicts faster than the L2ARC can maintain a headroom,
+ * then the L2ARC simply misses copying some buffers.  This serves as a
+ * pressure valve to prevent heavy read workloads from both stalling the ARC
+ * with waits and clogging the L2ARC with writes.  This also helps prevent
+ * the potential for the L2ARC to churn if it attempts to cache content too
+ * quickly, such as during backups of the entire pool.
+ *
+ * 5. After system boot and before the ARC has filled main memory, there are
+ * no evictions from the ARC and so the tails of the ARC_mfu and ARC_mru
+ * lists can remain mostly static.  Instead of searching from tail of these
+ * lists as pictured, the l2arc_feed_thread() will search from the list heads
+ * for eligible buffers, greatly increasing its chance of finding them.
+ *
+ * The L2ARC device write speed is also boosted during this time so that
+ * the L2ARC warms up faster.  Since there have been no ARC evictions yet,
+ * there are no L2ARC reads, and no fear of degrading read performance
+ * through increased writes.
+ *
+ * 6. Writes to the L2ARC devices are grouped and sent in-sequence, so that
+ * the vdev queue can aggregate them into larger and fewer writes.  Each
+ * device is written to in a rotor fashion, sweeping writes through
+ * available space then repeating.
+ *
+ * 7. The L2ARC does not store dirty content.  It never needs to flush
+ * write buffers back to disk based storage.
+ *
+ * 8. If an ARC buffer is written (and dirtied) which also exists in the
+ * L2ARC, the now stale L2ARC buffer is immediately dropped.
+ *
+ * The performance of the L2ARC can be tweaked by a number of tunables, which
+ * may be necessary for different workloads:
+ *
+ *	l2arc_write_max		max write bytes per interval
+ *	l2arc_write_boost	extra write bytes during device warmup
+ *	l2arc_noprefetch	skip caching prefetched buffers
+ *	l2arc_headroom		number of max device writes to precache
+ *	l2arc_feed_secs		seconds between L2ARC writing
+ *
+ * Tunables may be removed or added as future performance improvements are
+ * integrated, and also may become zpool properties.
+ */
+
+static void
+l2arc_hdr_stat_add(void)
+{
+	ARCSTAT_INCR(arcstat_l2_hdr_size, HDR_SIZE + L2HDR_SIZE);
+	ARCSTAT_INCR(arcstat_hdr_size, -HDR_SIZE);
+}
+
+static void
+l2arc_hdr_stat_remove(void)
+{
+	ARCSTAT_INCR(arcstat_l2_hdr_size, -(HDR_SIZE + L2HDR_SIZE));
+	ARCSTAT_INCR(arcstat_hdr_size, HDR_SIZE);
+}
+
+/*
+ * Cycle through L2ARC devices.  This is how L2ARC load balances.
+ * If a device is returned, this also returns holding the spa config lock.
+ */
+static l2arc_dev_t *
+l2arc_dev_get_next(void)
+{
+	l2arc_dev_t *first, *next = NULL;
+
+	/*
+	 * Lock out the removal of spas (spa_namespace_lock), then removal
+	 * of cache devices (l2arc_dev_mtx).  Once a device has been selected,
+	 * both locks will be dropped and a spa config lock held instead.
+	 */
+	mutex_enter(&spa_namespace_lock);
+	mutex_enter(&l2arc_dev_mtx);
+
+	/* if there are no vdevs, there is nothing to do */
+	if (l2arc_ndev == 0)
+		goto out;
+
+	first = NULL;
+	next = l2arc_dev_last;
+	do {
+		/* loop around the list looking for a non-faulted vdev */
+		if (next == NULL) {
+			next = list_head(l2arc_dev_list);
+		} else {
+			next = list_next(l2arc_dev_list, next);
+			if (next == NULL)
+				next = list_head(l2arc_dev_list);
+		}
+
+		/* if we have come back to the start, bail out */
+		if (first == NULL)
+			first = next;
+		else if (next == first)
+			break;
+
+	} while (vdev_is_dead(next->l2ad_vdev));
+
+	/* if we were unable to find any usable vdevs, return NULL */
+	if (vdev_is_dead(next->l2ad_vdev))
+		next = NULL;
+
+	l2arc_dev_last = next;
+
+out:
+	mutex_exit(&l2arc_dev_mtx);
+
+	/*
+	 * Grab the config lock to prevent the 'next' device from being
+	 * removed while we are writing to it.
+	 */
+	if (next != NULL)
+		spa_config_enter(next->l2ad_spa, SCL_L2ARC, next, RW_READER);
+	mutex_exit(&spa_namespace_lock);
+
+	return (next);
+}
+
+/*
+ * Free buffers that were tagged for destruction.
+ */
+static void
+l2arc_do_free_on_write()
+{
+	list_t *buflist;
+	l2arc_data_free_t *df, *df_prev;
+
+	mutex_enter(&l2arc_free_on_write_mtx);
+	buflist = l2arc_free_on_write;
+
+	for (df = list_tail(buflist); df; df = df_prev) {
+		df_prev = list_prev(buflist, df);
+		ASSERT(df->l2df_data != NULL);
+		ASSERT(df->l2df_func != NULL);
+		df->l2df_func(df->l2df_data, df->l2df_size);
+		list_remove(buflist, df);
+		kmem_free(df, sizeof (l2arc_data_free_t));
+	}
+
+	mutex_exit(&l2arc_free_on_write_mtx);
+}
+
+/*
+ * A write to a cache device has completed.  Update all headers to allow
+ * reads from these buffers to begin.
+ */
+static void
+l2arc_write_done(zio_t *zio)
+{
+	l2arc_write_callback_t *cb;
+	l2arc_dev_t *dev;
+	list_t *buflist;
+	arc_buf_hdr_t *head, *ab, *ab_prev;
+	l2arc_buf_hdr_t *abl2;
+	kmutex_t *hash_lock;
+
+	cb = zio->io_private;
+	ASSERT(cb != NULL);
+	dev = cb->l2wcb_dev;
+	ASSERT(dev != NULL);
+	head = cb->l2wcb_head;
+	ASSERT(head != NULL);
+	buflist = dev->l2ad_buflist;
+	ASSERT(buflist != NULL);
+	DTRACE_PROBE2(l2arc__iodone, zio_t *, zio,
+	    l2arc_write_callback_t *, cb);
+
+	if (zio->io_error != 0)
+		ARCSTAT_BUMP(arcstat_l2_writes_error);
+
+	mutex_enter(&l2arc_buflist_mtx);
+
+	/*
+	 * All writes completed, or an error was hit.
+	 */
+	for (ab = list_prev(buflist, head); ab; ab = ab_prev) {
+		ab_prev = list_prev(buflist, ab);
+
+		hash_lock = HDR_LOCK(ab);
+		if (!mutex_tryenter(hash_lock)) {
+			/*
+			 * This buffer misses out.  It may be in a stage
+			 * of eviction.  Its ARC_L2_WRITING flag will be
+			 * left set, denying reads to this buffer.
+			 */
+			ARCSTAT_BUMP(arcstat_l2_writes_hdr_miss);
+			continue;
+		}
+
+		if (zio->io_error != 0) {
+			/*
+			 * Error - drop L2ARC entry.
+			 */
+			list_remove(buflist, ab);
+			abl2 = ab->b_l2hdr;
+			ab->b_l2hdr = NULL;
+			kmem_free(abl2, sizeof (l2arc_buf_hdr_t));
+			ARCSTAT_INCR(arcstat_l2_size, -ab->b_size);
+		}
+
+		/*
+		 * Allow ARC to begin reads to this L2ARC entry.
+		 */
+		ab->b_flags &= ~ARC_L2_WRITING;
+
+		mutex_exit(hash_lock);
+	}
+
+	atomic_inc_64(&l2arc_writes_done);
+	list_remove(buflist, head);
+	kmem_cache_free(hdr_cache, head);
+	mutex_exit(&l2arc_buflist_mtx);
+
+	l2arc_do_free_on_write();
+
+	kmem_free(cb, sizeof (l2arc_write_callback_t));
+}
+
+/*
+ * A read to a cache device completed.  Validate buffer contents before
+ * handing over to the regular ARC routines.
+ */
+static void
+l2arc_read_done(zio_t *zio)
+{
+	l2arc_read_callback_t *cb;
+	arc_buf_hdr_t *hdr;
+	arc_buf_t *buf;
+	kmutex_t *hash_lock;
+	int equal;
+
+	ASSERT(zio->io_vd != NULL);
+	ASSERT(zio->io_flags & ZIO_FLAG_DONT_PROPAGATE);
+
+	spa_config_exit(zio->io_spa, SCL_L2ARC, zio->io_vd);
+
+	cb = zio->io_private;
+	ASSERT(cb != NULL);
+	buf = cb->l2rcb_buf;
+	ASSERT(buf != NULL);
+	hdr = buf->b_hdr;
+	ASSERT(hdr != NULL);
+
+	hash_lock = HDR_LOCK(hdr);
+	mutex_enter(hash_lock);
+
+	/*
+	 * Check this survived the L2ARC journey.
+	 */
+	equal = arc_cksum_equal(buf);
+	if (equal && zio->io_error == 0 && !HDR_L2_EVICTED(hdr)) {
+		mutex_exit(hash_lock);
+		zio->io_private = buf;
+		zio->io_bp_copy = cb->l2rcb_bp;	/* XXX fix in L2ARC 2.0	*/
+		zio->io_bp = &zio->io_bp_copy;	/* XXX fix in L2ARC 2.0	*/
+		arc_read_done(zio);
+	} else {
+		mutex_exit(hash_lock);
+		/*
+		 * Buffer didn't survive caching.  Increment stats and
+		 * reissue to the original storage device.
+		 */
+		if (zio->io_error != 0) {
+			ARCSTAT_BUMP(arcstat_l2_io_error);
+		} else {
+			zio->io_error = EIO;
+		}
+		if (!equal)
+			ARCSTAT_BUMP(arcstat_l2_cksum_bad);
+
+		/*
+		 * If there's no waiter, issue an async i/o to the primary
+		 * storage now.  If there *is* a waiter, the caller must
+		 * issue the i/o in a context where it's OK to block.
+		 */
+		if (zio->io_waiter == NULL)
+			zio_nowait(zio_read(zio->io_parent,
+			    cb->l2rcb_spa, &cb->l2rcb_bp,
+			    buf->b_data, zio->io_size, arc_read_done, buf,
+			    zio->io_priority, cb->l2rcb_flags, &cb->l2rcb_zb));
+	}
+
+	kmem_free(cb, sizeof (l2arc_read_callback_t));
+}
+
+/*
+ * This is the list priority from which the L2ARC will search for pages to
+ * cache.  This is used within loops (0..3) to cycle through lists in the
+ * desired order.  This order can have a significant effect on cache
+ * performance.
+ *
+ * Currently the metadata lists are hit first, MFU then MRU, followed by
+ * the data lists.  This function returns a locked list, and also returns
+ * the lock pointer.
+ */
+static list_t *
+l2arc_list_locked(int list_num, kmutex_t **lock)
+{
+	list_t *list;
+
+	ASSERT(list_num >= 0 && list_num <= 3);
+
+	switch (list_num) {
+	case 0:
+		list = &arc_mfu->arcs_list[ARC_BUFC_METADATA];
+		*lock = &arc_mfu->arcs_mtx;
+		break;
+	case 1:
+		list = &arc_mru->arcs_list[ARC_BUFC_METADATA];
+		*lock = &arc_mru->arcs_mtx;
+		break;
+	case 2:
+		list = &arc_mfu->arcs_list[ARC_BUFC_DATA];
+		*lock = &arc_mfu->arcs_mtx;
+		break;
+	case 3:
+		list = &arc_mru->arcs_list[ARC_BUFC_DATA];
+		*lock = &arc_mru->arcs_mtx;
+		break;
+	}
+
+	ASSERT(!(MUTEX_HELD(*lock)));
+	mutex_enter(*lock);
+	return (list);
+}
+
+/*
+ * Evict buffers from the device write hand to the distance specified in
+ * bytes.  This distance may span populated buffers, it may span nothing.
+ * This is clearing a region on the L2ARC device ready for writing.
+ * If the 'all' boolean is set, every buffer is evicted.
+ */
+static void
+l2arc_evict(l2arc_dev_t *dev, uint64_t distance, boolean_t all)
+{
+	list_t *buflist;
+	l2arc_buf_hdr_t *abl2;
+	arc_buf_hdr_t *ab, *ab_prev;
+	kmutex_t *hash_lock;
+	uint64_t taddr;
+
+	buflist = dev->l2ad_buflist;
+
+	if (buflist == NULL)
+		return;
+
+	if (!all && dev->l2ad_first) {
+		/*
+		 * This is the first sweep through the device.  There is
+		 * nothing to evict.
+		 */
+		return;
+	}
+
+	if (dev->l2ad_hand >= (dev->l2ad_end - (2 * distance))) {
+		/*
+		 * When nearing the end of the device, evict to the end
+		 * before the device write hand jumps to the start.
+		 */
+		taddr = dev->l2ad_end;
+	} else {
+		taddr = dev->l2ad_hand + distance;
+	}
+	DTRACE_PROBE4(l2arc__evict, l2arc_dev_t *, dev, list_t *, buflist,
+	    uint64_t, taddr, boolean_t, all);
+
+top:
+	mutex_enter(&l2arc_buflist_mtx);
+	for (ab = list_tail(buflist); ab; ab = ab_prev) {
+		ab_prev = list_prev(buflist, ab);
+
+		hash_lock = HDR_LOCK(ab);
+		if (!mutex_tryenter(hash_lock)) {
+			/*
+			 * Missed the hash lock.  Retry.
+			 */
+			ARCSTAT_BUMP(arcstat_l2_evict_lock_retry);
+			mutex_exit(&l2arc_buflist_mtx);
+			mutex_enter(hash_lock);
+			mutex_exit(hash_lock);
+			goto top;
+		}
+
+		if (HDR_L2_WRITE_HEAD(ab)) {
+			/*
+			 * We hit a write head node.  Leave it for
+			 * l2arc_write_done().
+			 */
+			list_remove(buflist, ab);
+			mutex_exit(hash_lock);
+			continue;
+		}
+
+		if (!all && ab->b_l2hdr != NULL &&
+		    (ab->b_l2hdr->b_daddr > taddr ||
+		    ab->b_l2hdr->b_daddr < dev->l2ad_hand)) {
+			/*
+			 * We've evicted to the target address,
+			 * or the end of the device.
+			 */
+			mutex_exit(hash_lock);
+			break;
+		}
+
+		if (HDR_FREE_IN_PROGRESS(ab)) {
+			/*
+			 * Already on the path to destruction.
+			 */
+			mutex_exit(hash_lock);
+			continue;
+		}
+
+		if (ab->b_state == arc_l2c_only) {
+			ASSERT(!HDR_L2_READING(ab));
+			/*
+			 * This doesn't exist in the ARC.  Destroy.
+			 * arc_hdr_destroy() will call list_remove()
+			 * and decrement arcstat_l2_size.
+			 */
+			arc_change_state(arc_anon, ab, hash_lock);
+			arc_hdr_destroy(ab);
+		} else {
+			/*
+			 * Invalidate issued or about to be issued
+			 * reads, since we may be about to write
+			 * over this location.
+			 */
+			if (HDR_L2_READING(ab)) {
+				ARCSTAT_BUMP(arcstat_l2_evict_reading);
+				ab->b_flags |= ARC_L2_EVICTED;
+			}
+
+			/*
+			 * Tell ARC this no longer exists in L2ARC.
+			 */
+			if (ab->b_l2hdr != NULL) {
+				abl2 = ab->b_l2hdr;
+				ab->b_l2hdr = NULL;
+				kmem_free(abl2, sizeof (l2arc_buf_hdr_t));
+				ARCSTAT_INCR(arcstat_l2_size, -ab->b_size);
+			}
+			list_remove(buflist, ab);
+
+			/*
+			 * This may have been leftover after a
+			 * failed write.
+			 */
+			ab->b_flags &= ~ARC_L2_WRITING;
+		}
+		mutex_exit(hash_lock);
+	}
+	mutex_exit(&l2arc_buflist_mtx);
+
+	spa_l2cache_space_update(dev->l2ad_vdev, 0, -(taddr - dev->l2ad_evict));
+	dev->l2ad_evict = taddr;
+}
+
+/*
+ * Find and write ARC buffers to the L2ARC device.
+ *
+ * An ARC_L2_WRITING flag is set so that the L2ARC buffers are not valid
+ * for reading until they have completed writing.
+ */
+static void
+l2arc_write_buffers(spa_t *spa, l2arc_dev_t *dev, uint64_t target_sz)
+{
+	arc_buf_hdr_t *ab, *ab_prev, *head;
+	l2arc_buf_hdr_t *hdrl2;
+	list_t *list;
+	uint64_t passed_sz, write_sz, buf_sz, headroom;
+	void *buf_data;
+	kmutex_t *hash_lock, *list_lock;
+	boolean_t have_lock, full;
+	l2arc_write_callback_t *cb;
+	zio_t *pio, *wzio;
+	int try;
+
+	ASSERT(dev->l2ad_vdev != NULL);
+
+	pio = NULL;
+	write_sz = 0;
+	full = B_FALSE;
+	head = kmem_cache_alloc(hdr_cache, KM_PUSHPAGE);
+	head->b_flags |= ARC_L2_WRITE_HEAD;
+
+	/*
+	 * Copy buffers for L2ARC writing.
+	 */
+	mutex_enter(&l2arc_buflist_mtx);
+	for (try = 0; try <= 3; try++) {
+		list = l2arc_list_locked(try, &list_lock);
+		passed_sz = 0;
+
+		/*
+		 * L2ARC fast warmup.
+		 *
+		 * Until the ARC is warm and starts to evict, read from the
+		 * head of the ARC lists rather than the tail.
+		 */
+		headroom = target_sz * l2arc_headroom;
+		if (arc_warm == B_FALSE)
+			ab = list_head(list);
+		else
+			ab = list_tail(list);
+
+		for (; ab; ab = ab_prev) {
+			if (arc_warm == B_FALSE)
+				ab_prev = list_next(list, ab);
+			else
+				ab_prev = list_prev(list, ab);
+
+			hash_lock = HDR_LOCK(ab);
+			have_lock = MUTEX_HELD(hash_lock);
+			if (!have_lock && !mutex_tryenter(hash_lock)) {
+				/*
+				 * Skip this buffer rather than waiting.
+				 */
+				continue;
+			}
+
+			passed_sz += ab->b_size;
+			if (passed_sz > headroom) {
+				/*
+				 * Searched too far.
+				 */
+				mutex_exit(hash_lock);
+				break;
+			}
+
+			if (ab->b_spa != spa) {
+				mutex_exit(hash_lock);
+				continue;
+			}
+
+			if (ab->b_l2hdr != NULL) {
+				/*
+				 * Already in L2ARC.
+				 */
+				mutex_exit(hash_lock);
+				continue;
+			}
+
+			if (HDR_IO_IN_PROGRESS(ab) || !HDR_L2CACHE(ab)) {
+				mutex_exit(hash_lock);
+				continue;
+			}
+
+			if ((write_sz + ab->b_size) > target_sz) {
+				full = B_TRUE;
+				mutex_exit(hash_lock);
+				break;
+			}
+
+			if (ab->b_buf == NULL) {
+				DTRACE_PROBE1(l2arc__buf__null, void *, ab);
+				mutex_exit(hash_lock);
+				continue;
+			}
+
+			if (pio == NULL) {
+				/*
+				 * Insert a dummy header on the buflist so
+				 * l2arc_write_done() can find where the
+				 * write buffers begin without searching.
+				 */
+				list_insert_head(dev->l2ad_buflist, head);
+
+				cb = kmem_alloc(
+				    sizeof (l2arc_write_callback_t), KM_SLEEP);
+				cb->l2wcb_dev = dev;
+				cb->l2wcb_head = head;
+				pio = zio_root(spa, l2arc_write_done, cb,
+				    ZIO_FLAG_CANFAIL);
+			}
+
+			/*
+			 * Create and add a new L2ARC header.
+			 */
+			hdrl2 = kmem_zalloc(sizeof (l2arc_buf_hdr_t), KM_SLEEP);
+			hdrl2->b_dev = dev;
+			hdrl2->b_daddr = dev->l2ad_hand;
+
+			ab->b_flags |= ARC_L2_WRITING;
+			ab->b_l2hdr = hdrl2;
+			list_insert_head(dev->l2ad_buflist, ab);
+			buf_data = ab->b_buf->b_data;
+			buf_sz = ab->b_size;
+
+			/*
+			 * Compute and store the buffer cksum before
+			 * writing.  On debug the cksum is verified first.
+			 */
+			arc_cksum_verify(ab->b_buf);
+			arc_cksum_compute(ab->b_buf, B_TRUE);
+
+			mutex_exit(hash_lock);
+
+			wzio = zio_write_phys(pio, dev->l2ad_vdev,
+			    dev->l2ad_hand, buf_sz, buf_data, ZIO_CHECKSUM_OFF,
+			    NULL, NULL, ZIO_PRIORITY_ASYNC_WRITE,
+			    ZIO_FLAG_CANFAIL, B_FALSE);
+
+			DTRACE_PROBE2(l2arc__write, vdev_t *, dev->l2ad_vdev,
+			    zio_t *, wzio);
+			(void) zio_nowait(wzio);
+
+			/*
+			 * Keep the clock hand suitably device-aligned.
+			 */
+			buf_sz = vdev_psize_to_asize(dev->l2ad_vdev, buf_sz);
+
+			write_sz += buf_sz;
+			dev->l2ad_hand += buf_sz;
+		}
+
+		mutex_exit(list_lock);
+
+		if (full == B_TRUE)
+			break;
+	}
+	mutex_exit(&l2arc_buflist_mtx);
+
+	if (pio == NULL) {
+		ASSERT3U(write_sz, ==, 0);
+		kmem_cache_free(hdr_cache, head);
+		return;
+	}
+
+	ASSERT3U(write_sz, <=, target_sz);
+	ARCSTAT_BUMP(arcstat_l2_writes_sent);
+	ARCSTAT_INCR(arcstat_l2_size, write_sz);
+	spa_l2cache_space_update(dev->l2ad_vdev, 0, write_sz);
+
+	/*
+	 * Bump device hand to the device start if it is approaching the end.
+	 * l2arc_evict() will already have evicted ahead for this case.
+	 */
+	if (dev->l2ad_hand >= (dev->l2ad_end - target_sz)) {
+		spa_l2cache_space_update(dev->l2ad_vdev, 0,
+		    dev->l2ad_end - dev->l2ad_hand);
+		dev->l2ad_hand = dev->l2ad_start;
+		dev->l2ad_evict = dev->l2ad_start;
+		dev->l2ad_first = B_FALSE;
+	}
+
+	(void) zio_wait(pio);
+}
+
+/*
+ * This thread feeds the L2ARC at regular intervals.  This is the beating
+ * heart of the L2ARC.
+ */
+static void
+l2arc_feed_thread(void *dummy __unused)
+{
+	callb_cpr_t cpr;
+	l2arc_dev_t *dev;
+	spa_t *spa;
+	uint64_t size;
+
+	CALLB_CPR_INIT(&cpr, &l2arc_feed_thr_lock, callb_generic_cpr, FTAG);
+
+	mutex_enter(&l2arc_feed_thr_lock);
+
+	while (l2arc_thread_exit == 0) {
+		/*
+		 * Pause for l2arc_feed_secs seconds between writes.
+		 */
+		CALLB_CPR_SAFE_BEGIN(&cpr);
+		(void) cv_timedwait(&l2arc_feed_thr_cv, &l2arc_feed_thr_lock,
+		    hz * l2arc_feed_secs);
+		CALLB_CPR_SAFE_END(&cpr, &l2arc_feed_thr_lock);
+
+		/*
+		 * Quick check for L2ARC devices.
+		 */
+		mutex_enter(&l2arc_dev_mtx);
+		if (l2arc_ndev == 0) {
+			mutex_exit(&l2arc_dev_mtx);
+			continue;
+		}
+		mutex_exit(&l2arc_dev_mtx);
+
+		/*
+		 * This selects the next l2arc device to write to, and in
+		 * doing so the next spa to feed from: dev->l2ad_spa.   This
+		 * will return NULL if there are now no l2arc devices or if
+		 * they are all faulted.
+		 *
+		 * If a device is returned, its spa's config lock is also
+		 * held to prevent device removal.  l2arc_dev_get_next()
+		 * will grab and release l2arc_dev_mtx.
+		 */
+		if ((dev = l2arc_dev_get_next()) == NULL)
+			continue;
+
+		spa = dev->l2ad_spa;
+		ASSERT(spa != NULL);
+
+		/*
+		 * Avoid contributing to memory pressure.
+		 */
+		if (arc_reclaim_needed()) {
+			ARCSTAT_BUMP(arcstat_l2_abort_lowmem);
+			spa_config_exit(spa, SCL_L2ARC, dev);
+			continue;
+		}
+
+		ARCSTAT_BUMP(arcstat_l2_feeds);
+
+		size = dev->l2ad_write;
+		if (arc_warm == B_FALSE)
+			size += dev->l2ad_boost;
+
+		/*
+		 * Evict L2ARC buffers that will be overwritten.
+		 */
+		l2arc_evict(dev, size, B_FALSE);
+
+		/*
+		 * Write ARC buffers.
+		 */
+		l2arc_write_buffers(spa, dev, size);
+		spa_config_exit(spa, SCL_L2ARC, dev);
+	}
+
+	l2arc_thread_exit = 0;
+	cv_broadcast(&l2arc_feed_thr_cv);
+	CALLB_CPR_EXIT(&cpr);		/* drops l2arc_feed_thr_lock */
+	thread_exit();
+}
+
+boolean_t
+l2arc_vdev_present(vdev_t *vd)
+{
+	l2arc_dev_t *dev;
+
+	mutex_enter(&l2arc_dev_mtx);
+	for (dev = list_head(l2arc_dev_list); dev != NULL;
+	    dev = list_next(l2arc_dev_list, dev)) {
+		if (dev->l2ad_vdev == vd)
+			break;
+	}
+	mutex_exit(&l2arc_dev_mtx);
+
+	return (dev != NULL);
+}
+
+/*
+ * Add a vdev for use by the L2ARC.  By this point the spa has already
+ * validated the vdev and opened it.
+ */
+void
+l2arc_add_vdev(spa_t *spa, vdev_t *vd, uint64_t start, uint64_t end)
+{
+	l2arc_dev_t *adddev;
+
+	ASSERT(!l2arc_vdev_present(vd));
+
+	/*
+	 * Create a new l2arc device entry.
+	 */
+	adddev = kmem_zalloc(sizeof (l2arc_dev_t), KM_SLEEP);
+	adddev->l2ad_spa = spa;
+	adddev->l2ad_vdev = vd;
+	adddev->l2ad_write = l2arc_write_max;
+	adddev->l2ad_boost = l2arc_write_boost;
+	adddev->l2ad_start = start;
+	adddev->l2ad_end = end;
+	adddev->l2ad_hand = adddev->l2ad_start;
+	adddev->l2ad_evict = adddev->l2ad_start;
+	adddev->l2ad_first = B_TRUE;
+	ASSERT3U(adddev->l2ad_write, >, 0);
+
+	/*
+	 * This is a list of all ARC buffers that are still valid on the
+	 * device.
+	 */
+	adddev->l2ad_buflist = kmem_zalloc(sizeof (list_t), KM_SLEEP);
+	list_create(adddev->l2ad_buflist, sizeof (arc_buf_hdr_t),
+	    offsetof(arc_buf_hdr_t, b_l2node));
+
+	spa_l2cache_space_update(vd, adddev->l2ad_end - adddev->l2ad_hand, 0);
+
+	/*
+	 * Add device to global list
+	 */
+	mutex_enter(&l2arc_dev_mtx);
+	list_insert_head(l2arc_dev_list, adddev);
+	atomic_inc_64(&l2arc_ndev);
+	mutex_exit(&l2arc_dev_mtx);
+}
+
+/*
+ * Remove a vdev from the L2ARC.
+ */
+void
+l2arc_remove_vdev(vdev_t *vd)
+{
+	l2arc_dev_t *dev, *nextdev, *remdev = NULL;
+
+	/*
+	 * Find the device by vdev
+	 */
+	mutex_enter(&l2arc_dev_mtx);
+	for (dev = list_head(l2arc_dev_list); dev; dev = nextdev) {
+		nextdev = list_next(l2arc_dev_list, dev);
+		if (vd == dev->l2ad_vdev) {
+			remdev = dev;
+			break;
+		}
+	}
+	ASSERT(remdev != NULL);
+
+	/*
+	 * Remove device from global list
+	 */
+	list_remove(l2arc_dev_list, remdev);
+	l2arc_dev_last = NULL;		/* may have been invalidated */
+	atomic_dec_64(&l2arc_ndev);
+	mutex_exit(&l2arc_dev_mtx);
+
+	/*
+	 * Clear all buflists and ARC references.  L2ARC device flush.
+	 */
+	l2arc_evict(remdev, 0, B_TRUE);
+	list_destroy(remdev->l2ad_buflist);
+	kmem_free(remdev->l2ad_buflist, sizeof (list_t));
+	kmem_free(remdev, sizeof (l2arc_dev_t));
+}
+
+void
+l2arc_init(void)
+{
+	l2arc_thread_exit = 0;
+	l2arc_ndev = 0;
+	l2arc_writes_sent = 0;
+	l2arc_writes_done = 0;
+
+	mutex_init(&l2arc_feed_thr_lock, NULL, MUTEX_DEFAULT, NULL);
+	cv_init(&l2arc_feed_thr_cv, NULL, CV_DEFAULT, NULL);
+	mutex_init(&l2arc_dev_mtx, NULL, MUTEX_DEFAULT, NULL);
+	mutex_init(&l2arc_buflist_mtx, NULL, MUTEX_DEFAULT, NULL);
+	mutex_init(&l2arc_free_on_write_mtx, NULL, MUTEX_DEFAULT, NULL);
+
+	l2arc_dev_list = &L2ARC_dev_list;
+	l2arc_free_on_write = &L2ARC_free_on_write;
+	list_create(l2arc_dev_list, sizeof (l2arc_dev_t),
+	    offsetof(l2arc_dev_t, l2ad_node));
+	list_create(l2arc_free_on_write, sizeof (l2arc_data_free_t),
+	    offsetof(l2arc_data_free_t, l2df_list_node));
+}
+
+void
+l2arc_fini(void)
+{
+	/*
+	 * This is called from dmu_fini(), which is called from spa_fini();
+	 * Because of this, we can assume that all l2arc devices have
+	 * already been removed when the pools themselves were removed.
+	 */
+
+	l2arc_do_free_on_write();
+
+	mutex_destroy(&l2arc_feed_thr_lock);
+	cv_destroy(&l2arc_feed_thr_cv);
+	mutex_destroy(&l2arc_dev_mtx);
+	mutex_destroy(&l2arc_buflist_mtx);
+	mutex_destroy(&l2arc_free_on_write_mtx);
+
+	list_destroy(l2arc_dev_list);
+	list_destroy(l2arc_free_on_write);
+}
+
+void
+l2arc_start(void)
+{
+	if (!(spa_mode & FWRITE))
+		return;
+
+	(void) thread_create(NULL, 0, l2arc_feed_thread, NULL, 0, &p0,
+	    TS_RUN, minclsyspri);
+}
+
+void
+l2arc_stop(void)
+{
+	if (!(spa_mode & FWRITE))
+		return;
+
+	mutex_enter(&l2arc_feed_thr_lock);
+	cv_signal(&l2arc_feed_thr_cv);	/* kick thread out of startup */
+	l2arc_thread_exit = 1;
+	while (l2arc_thread_exit != 0)
+		cv_wait(&l2arc_feed_thr_cv, &l2arc_feed_thr_lock);
+	mutex_exit(&l2arc_feed_thr_lock);
+}
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/bplist.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/bplist.c
index 4442b1f28ac8..93b7741d77be 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/bplist.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/bplist.c
@@ -19,12 +19,10 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
-#pragma ident	"%Z%%M%	%I%	%E% SMI"
-
 #include <sys/bplist.h>
 #include <sys/zfs_context.h>
 
@@ -47,7 +45,7 @@ bplist_create(objset_t *mos, int blocksize, dmu_tx_t *tx)
 {
 	int size;
 
-	size = spa_version(dmu_objset_spa(mos)) < ZFS_VERSION_BPLIST_ACCOUNT ?
+	size = spa_version(dmu_objset_spa(mos)) < SPA_VERSION_BPLIST_ACCOUNT ?
 	    BPLIST_SIZE_V0 : sizeof (bplist_phys_t);
 
 	return (dmu_object_alloc(mos, DMU_OT_BPLIST, blocksize,
@@ -181,7 +179,7 @@ bplist_iterate(bplist_t *bpl, uint64_t *itorp, blkptr_t *bp)
 }
 
 int
-bplist_enqueue(bplist_t *bpl, blkptr_t *bp, dmu_tx_t *tx)
+bplist_enqueue(bplist_t *bpl, const blkptr_t *bp, dmu_tx_t *tx)
 {
 	uint64_t blk, off;
 	blkptr_t *bparray;
@@ -229,7 +227,7 @@ bplist_enqueue(bplist_t *bpl, blkptr_t *bp, dmu_tx_t *tx)
  * Deferred entry; will be written later by bplist_sync().
  */
 void
-bplist_enqueue_deferred(bplist_t *bpl, blkptr_t *bp)
+bplist_enqueue_deferred(bplist_t *bpl, const blkptr_t *bp)
 {
 	bplist_q_t *bpq = kmem_alloc(sizeof (*bpq), KM_SLEEP);
 
@@ -278,9 +276,7 @@ bplist_vacate(bplist_t *bpl, dmu_tx_t *tx)
 int
 bplist_space(bplist_t *bpl, uint64_t *usedp, uint64_t *compp, uint64_t *uncompp)
 {
-	uint64_t itor = 0, comp = 0, uncomp = 0;
 	int err;
-	blkptr_t bp;
 
 	mutex_enter(&bpl->bpl_lock);
 
@@ -298,6 +294,9 @@ bplist_space(bplist_t *bpl, uint64_t *usedp, uint64_t *compp, uint64_t *uncompp)
 	mutex_exit(&bpl->bpl_lock);
 
 	if (!bpl->bpl_havecomp) {
+		uint64_t itor = 0, comp = 0, uncomp = 0;
+		blkptr_t bp;
+
 		while ((err = bplist_iterate(bpl, &itor, &bp)) == 0) {
 			comp += BP_GET_PSIZE(&bp);
 			uncomp += BP_GET_UCSIZE(&bp);
@@ -310,3 +309,41 @@ bplist_space(bplist_t *bpl, uint64_t *usedp, uint64_t *compp, uint64_t *uncompp)
 
 	return (err);
 }
+
+/*
+ * Return (in *dasizep) the amount of space on the deadlist which is:
+ * mintxg < blk_birth <= maxtxg
+ */
+int
+bplist_space_birthrange(bplist_t *bpl, uint64_t mintxg, uint64_t maxtxg,
+    uint64_t *dasizep)
+{
+	uint64_t size = 0;
+	uint64_t itor = 0;
+	blkptr_t bp;
+	int err;
+
+	/*
+	 * As an optimization, if they want the whole txg range, just
+	 * get bpl_bytes rather than iterating over the bps.
+	 */
+	if (mintxg < TXG_INITIAL && maxtxg == UINT64_MAX) {
+		mutex_enter(&bpl->bpl_lock);
+		err = bplist_hold(bpl);
+		if (err == 0)
+			*dasizep = bpl->bpl_phys->bpl_bytes;
+		mutex_exit(&bpl->bpl_lock);
+		return (err);
+	}
+
+	while ((err = bplist_iterate(bpl, &itor, &bp)) == 0) {
+		if (bp.blk_birth > mintxg && bp.blk_birth <= maxtxg) {
+			size +=
+			    bp_get_dasize(dmu_objset_spa(bpl->bpl_mos), &bp);
+		}
+	}
+	if (err == ENOENT)
+		err = 0;
+	*dasizep = size;
+	return (err);
+}
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dbuf.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dbuf.c
index 94c63081478a..2494c1e7f9d1 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dbuf.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dbuf.c
@@ -19,12 +19,10 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
-#pragma ident	"%Z%%M%	%I%	%E% SMI"
-
 #include <sys/zfs_context.h>
 #include <sys/dmu.h>
 #include <sys/dmu_impl.h>
@@ -39,17 +37,10 @@
 
 static void dbuf_destroy(dmu_buf_impl_t *db);
 static int dbuf_undirty(dmu_buf_impl_t *db, dmu_tx_t *tx);
-static void dbuf_write(dbuf_dirty_record_t *dr, arc_buf_t *data, int checksum,
-    int compress, dmu_tx_t *tx);
+static void dbuf_write(dbuf_dirty_record_t *dr, arc_buf_t *data, dmu_tx_t *tx);
 static arc_done_func_t dbuf_write_ready;
 static arc_done_func_t dbuf_write_done;
 
-int zfs_mdcomp_disable = 0;
-SYSCTL_DECL(_vfs_zfs);
-TUNABLE_INT("vfs.zfs.mdcomp_disable", &zfs_mdcomp_disable);
-SYSCTL_INT(_vfs_zfs, OID_AUTO, mdcomp_disable, CTLFLAG_RDTUN,
-    &zfs_mdcomp_disable, 0, "Disable metadata compression");
-
 /*
  * Global data structures and functions for the dbuf cache.
  */
@@ -311,7 +302,7 @@ dbuf_verify(dmu_buf_impl_t *db)
 	}
 	if (db->db_blkid == DB_BONUS_BLKID) {
 		ASSERT(dn != NULL);
-		ASSERT3U(db->db.db_size, ==, dn->dn_bonuslen);
+		ASSERT3U(db->db.db_size, >=, dn->dn_bonuslen);
 		ASSERT3U(db->db.db_offset, ==, DB_BONUS_BLKID);
 	} else {
 		ASSERT3U(db->db.db_offset, ==, db->db_blkid * db->db.db_size);
@@ -460,45 +451,45 @@ dbuf_read_done(zio_t *zio, arc_buf_t *buf, void *vdb)
 static void
 dbuf_read_impl(dmu_buf_impl_t *db, zio_t *zio, uint32_t *flags)
 {
-	blkptr_t *bp;
+	dnode_t *dn = db->db_dnode;
 	zbookmark_t zb;
 	uint32_t aflags = ARC_NOWAIT;
+	arc_buf_t *pbuf;
 
 	ASSERT(!refcount_is_zero(&db->db_holds));
 	/* We need the struct_rwlock to prevent db_blkptr from changing. */
-	ASSERT(RW_LOCK_HELD(&db->db_dnode->dn_struct_rwlock));
+	ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock));
 	ASSERT(MUTEX_HELD(&db->db_mtx));
 	ASSERT(db->db_state == DB_UNCACHED);
 	ASSERT(db->db_buf == NULL);
 
 	if (db->db_blkid == DB_BONUS_BLKID) {
-		ASSERT3U(db->db_dnode->dn_bonuslen, ==, db->db.db_size);
+		int bonuslen = dn->dn_bonuslen;
+
+		ASSERT3U(bonuslen, <=, db->db.db_size);
 		db->db.db_data = zio_buf_alloc(DN_MAX_BONUSLEN);
-		if (db->db.db_size < DN_MAX_BONUSLEN)
+		arc_space_consume(DN_MAX_BONUSLEN);
+		if (bonuslen < DN_MAX_BONUSLEN)
 			bzero(db->db.db_data, DN_MAX_BONUSLEN);
-		bcopy(DN_BONUS(db->db_dnode->dn_phys), db->db.db_data,
-		    db->db.db_size);
+		bcopy(DN_BONUS(dn->dn_phys), db->db.db_data,
+		    bonuslen);
 		dbuf_update_data(db);
 		db->db_state = DB_CACHED;
 		mutex_exit(&db->db_mtx);
 		return;
 	}
 
-	if (db->db_level == 0 && dnode_block_freed(db->db_dnode, db->db_blkid))
-		bp = NULL;
-	else
-		bp = db->db_blkptr;
-
-	if (bp == NULL)
-		dprintf_dbuf(db, "blkptr: %s\n", "NULL");
-	else
-		dprintf_dbuf_bp(db, bp, "%s", "blkptr:");
-
-	if (bp == NULL || BP_IS_HOLE(bp)) {
+	/*
+	 * Recheck BP_IS_HOLE() after dnode_block_freed() in case dnode_sync()
+	 * processes the delete record and clears the bp while we are waiting
+	 * for the dn_mtx (resulting in a "no" from block_freed).
+	 */
+	if (db->db_blkptr == NULL || BP_IS_HOLE(db->db_blkptr) ||
+	    (db->db_level == 0 && (dnode_block_freed(dn, db->db_blkid) ||
+	    BP_IS_HOLE(db->db_blkptr)))) {
 		arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
 
-		ASSERT(bp == NULL || BP_IS_HOLE(bp));
-		dbuf_set_data(db, arc_buf_alloc(db->db_dnode->dn_objset->os_spa,
+		dbuf_set_data(db, arc_buf_alloc(dn->dn_objset->os_spa,
 		    db->db.db_size, db, type));
 		bzero(db->db.db_data, db->db.db_size);
 		db->db_state = DB_CACHED;
@@ -510,6 +501,9 @@ dbuf_read_impl(dmu_buf_impl_t *db, zio_t *zio, uint32_t *flags)
 	db->db_state = DB_READ;
 	mutex_exit(&db->db_mtx);
 
+	if (DBUF_IS_L2CACHEABLE(db))
+		aflags |= ARC_L2CACHE;
+
 	zb.zb_objset = db->db_objset->os_dsl_dataset ?
 	    db->db_objset->os_dsl_dataset->ds_object : 0;
 	zb.zb_object = db->db.db_object;
@@ -518,10 +512,13 @@ dbuf_read_impl(dmu_buf_impl_t *db, zio_t *zio, uint32_t *flags)
 
 	dbuf_add_ref(db, NULL);
 	/* ZIO_FLAG_CANFAIL callers have to check the parent zio's error */
-	ASSERT3U(db->db_dnode->dn_type, <, DMU_OT_NUMTYPES);
-	(void) arc_read(zio, db->db_dnode->dn_objset->os_spa, bp,
-	    db->db_level > 0 ? byteswap_uint64_array :
-	    dmu_ot[db->db_dnode->dn_type].ot_byteswap,
+
+	if (db->db_parent)
+		pbuf = db->db_parent->db_buf;
+	else
+		pbuf = db->db_objset->os_phys_buf;
+
+	(void) arc_read(zio, dn->dn_objset->os_spa, db->db_blkptr, pbuf,
 	    dbuf_read_done, db, ZIO_PRIORITY_SYNC_READ,
 	    (*flags & DB_RF_CANFAIL) ? ZIO_FLAG_CANFAIL : ZIO_FLAG_MUSTSUCCEED,
 	    &aflags, &zb);
@@ -546,7 +543,8 @@ dbuf_read(dmu_buf_impl_t *db, zio_t *zio, uint32_t flags)
 		rw_enter(&db->db_dnode->dn_struct_rwlock, RW_READER);
 
 	prefetch = db->db_level == 0 && db->db_blkid != DB_BONUS_BLKID &&
-	    (flags & DB_RF_NOPREFETCH) == 0 && db->db_dnode != NULL;
+	    (flags & DB_RF_NOPREFETCH) == 0 && db->db_dnode != NULL &&
+	    DBUF_IS_CACHEABLE(db);
 
 	mutex_enter(&db->db_mtx);
 	if (db->db_state == DB_CACHED) {
@@ -661,6 +659,7 @@ dbuf_fix_old_data(dmu_buf_impl_t *db, uint64_t txg)
 	if (db->db_blkid == DB_BONUS_BLKID) {
 		/* Note that the data bufs here are zio_bufs */
 		dr->dt.dl.dr_data = zio_buf_alloc(DN_MAX_BONUSLEN);
+		arc_space_consume(DN_MAX_BONUSLEN);
 		bcopy(db->db.db_data, dr->dt.dl.dr_data, DN_MAX_BONUSLEN);
 	} else if (refcount_count(&db->db_holds) > db->db_dirtycnt) {
 		int size = db->db.db_size;
@@ -690,7 +689,8 @@ dbuf_unoverride(dbuf_dirty_record_t *dr)
 	/* free this block */
 	if (!BP_IS_HOLE(&dr->dt.dl.dr_overridden_by)) {
 		/* XXX can get silent EIO here */
-		(void) arc_free(NULL, db->db_dnode->dn_objset->os_spa,
+		(void) dsl_free(NULL,
+		    spa_get_dsl(db->db_dnode->dn_objset->os_spa),
 		    txg, &dr->dt.dl.dr_overridden_by, NULL, NULL, ARC_WAIT);
 	}
 	dr->dt.dl.dr_override_state = DR_NOT_OVERRIDDEN;
@@ -705,22 +705,50 @@ dbuf_unoverride(dbuf_dirty_record_t *dr)
 	arc_release(dr->dt.dl.dr_data, db);
 }
 
+/*
+ * Evict (if its unreferenced) or clear (if its referenced) any level-0
+ * data blocks in the free range, so that any future readers will find
+ * empty blocks.  Also, if we happen accross any level-1 dbufs in the
+ * range that have not already been marked dirty, mark them dirty so
+ * they stay in memory.
+ */
 void
-dbuf_free_range(dnode_t *dn, uint64_t blkid, uint64_t nblks, dmu_tx_t *tx)
+dbuf_free_range(dnode_t *dn, uint64_t start, uint64_t end, dmu_tx_t *tx)
 {
 	dmu_buf_impl_t *db, *db_next;
 	uint64_t txg = tx->tx_txg;
+	int epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT;
+	uint64_t first_l1 = start >> epbs;
+	uint64_t last_l1 = end >> epbs;
 
-	dprintf_dnode(dn, "blkid=%llu nblks=%llu\n", blkid, nblks);
+	if (end > dn->dn_maxblkid) {
+		end = dn->dn_maxblkid;
+		last_l1 = end >> epbs;
+	}
+	dprintf_dnode(dn, "start=%llu end=%llu\n", start, end);
 	mutex_enter(&dn->dn_dbufs_mtx);
 	for (db = list_head(&dn->dn_dbufs); db; db = db_next) {
 		db_next = list_next(&dn->dn_dbufs, db);
 		ASSERT(db->db_blkid != DB_BONUS_BLKID);
+
+		if (db->db_level == 1 &&
+		    db->db_blkid >= first_l1 && db->db_blkid <= last_l1) {
+			mutex_enter(&db->db_mtx);
+			if (db->db_last_dirty &&
+			    db->db_last_dirty->dr_txg < txg) {
+				dbuf_add_ref(db, FTAG);
+				mutex_exit(&db->db_mtx);
+				dbuf_will_dirty(db, tx);
+				dbuf_rele(db, FTAG);
+			} else {
+				mutex_exit(&db->db_mtx);
+			}
+		}
+
 		if (db->db_level != 0)
 			continue;
 		dprintf_dbuf(db, "found buf %s\n", "");
-		if (db->db_blkid < blkid ||
-		    db->db_blkid >= blkid+nblks)
+		if (db->db_blkid < start || db->db_blkid > end)
 			continue;
 
 		/* found a level 0 buffer in the range */
@@ -783,31 +811,28 @@ dbuf_free_range(dnode_t *dn, uint64_t blkid, uint64_t nblks, dmu_tx_t *tx)
 }
 
 static int
-dbuf_new_block(dmu_buf_impl_t *db)
+dbuf_block_freeable(dmu_buf_impl_t *db)
 {
 	dsl_dataset_t *ds = db->db_objset->os_dsl_dataset;
 	uint64_t birth_txg = 0;
 
-	/* Don't count meta-objects */
-	if (ds == NULL)
-		return (FALSE);
-
 	/*
 	 * We don't need any locking to protect db_blkptr:
 	 * If it's syncing, then db_last_dirty will be set
 	 * so we'll ignore db_blkptr.
 	 */
 	ASSERT(MUTEX_HELD(&db->db_mtx));
-	/* If we have been dirtied since the last snapshot, its not new */
 	if (db->db_last_dirty)
 		birth_txg = db->db_last_dirty->dr_txg;
 	else if (db->db_blkptr)
 		birth_txg = db->db_blkptr->blk_birth;
 
+	/* If we don't exist or are in a snapshot, we can't be freed */
 	if (birth_txg)
-		return (!dsl_dataset_block_freeable(ds, birth_txg));
+		return (ds == NULL ||
+		    dsl_dataset_block_freeable(ds, birth_txg));
 	else
-		return (TRUE);
+		return (FALSE);
 }
 
 void
@@ -865,6 +890,7 @@ dbuf_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx)
 	objset_impl_t *os = dn->dn_objset;
 	dbuf_dirty_record_t **drp, *dr;
 	int drop_struct_lock = FALSE;
+	boolean_t do_free_accounting = B_FALSE;
 	int txgoff = tx->tx_txg & TXG_MASK;
 
 	ASSERT(tx->tx_txg != 0);
@@ -922,20 +948,20 @@ dbuf_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx)
 	drp = &db->db_last_dirty;
 	ASSERT(*drp == NULL || (*drp)->dr_txg <= tx->tx_txg ||
 	    db->db.db_object == DMU_META_DNODE_OBJECT);
-	while (*drp && (*drp)->dr_txg > tx->tx_txg)
-		drp = &(*drp)->dr_next;
-	if (*drp && (*drp)->dr_txg == tx->tx_txg) {
+	while ((dr = *drp) != NULL && dr->dr_txg > tx->tx_txg)
+		drp = &dr->dr_next;
+	if (dr && dr->dr_txg == tx->tx_txg) {
 		if (db->db_level == 0 && db->db_blkid != DB_BONUS_BLKID) {
 			/*
 			 * If this buffer has already been written out,
 			 * we now need to reset its state.
 			 */
-			dbuf_unoverride(*drp);
+			dbuf_unoverride(dr);
 			if (db->db.db_object != DMU_META_DNODE_OBJECT)
 				arc_buf_thaw(db->db_buf);
 		}
 		mutex_exit(&db->db_mtx);
-		return (*drp);
+		return (dr);
 	}
 
 	/*
@@ -966,6 +992,18 @@ dbuf_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx)
 
 	dprintf_dbuf(db, "size=%llx\n", (u_longlong_t)db->db.db_size);
 
+	if (db->db_blkid != DB_BONUS_BLKID) {
+		/*
+		 * Update the accounting.
+		 * Note: we delay "free accounting" until after we drop
+		 * the db_mtx.  This keeps us from grabbing other locks
+		 * (and possibly deadlocking) in bp_get_dasize() while
+		 * also holding the db_mtx.
+		 */
+		dnode_willuse_space(dn, db->db.db_size, tx);
+		do_free_accounting = dbuf_block_freeable(db);
+	}
+
 	/*
 	 * If this buffer is dirty in an old transaction group we need
 	 * to make a copy of it so that the changes we make in this
@@ -1015,25 +1053,6 @@ dbuf_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx)
 		db->db_freed_in_flight = FALSE;
 	}
 
-	if (db->db_blkid != DB_BONUS_BLKID) {
-		/*
-		 * Update the accounting.
-		 */
-		if (!dbuf_new_block(db) && db->db_blkptr) {
-			/*
-			 * This is only a guess -- if the dbuf is dirty
-			 * in a previous txg, we don't know how much
-			 * space it will use on disk yet.  We should
-			 * really have the struct_rwlock to access
-			 * db_blkptr, but since this is just a guess,
-			 * it's OK if we get an odd answer.
-			 */
-			dnode_willuse_space(dn,
-			    -bp_get_dasize(os->os_spa, db->db_blkptr), tx);
-		}
-		dnode_willuse_space(dn, db->db.db_size, tx);
-	}
-
 	/*
 	 * This buffer is now part of this txg
 	 */
@@ -1050,11 +1069,19 @@ dbuf_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx)
 		mutex_exit(&dn->dn_mtx);
 		dnode_setdirty(dn, tx);
 		return (dr);
-	}
-
-	if (db->db_level == 0) {
-		dnode_new_blkid(dn, db->db_blkid, tx);
-		ASSERT(dn->dn_maxblkid >= db->db_blkid);
+	} else if (do_free_accounting) {
+		blkptr_t *bp = db->db_blkptr;
+		int64_t willfree = (bp && !BP_IS_HOLE(bp)) ?
+		    bp_get_dasize(os->os_spa, bp) : db->db.db_size;
+		/*
+		 * This is only a guess -- if the dbuf is dirty
+		 * in a previous txg, we don't know how much
+		 * space it will use on disk yet.  We should
+		 * really have the struct_rwlock to access
+		 * db_blkptr, but since this is just a guess,
+		 * it's OK if we get an odd answer.
+		 */
+		dnode_willuse_space(dn, -willfree, tx);
 	}
 
 	if (!RW_WRITE_HELD(&dn->dn_struct_rwlock)) {
@@ -1062,6 +1089,11 @@ dbuf_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx)
 		drop_struct_lock = TRUE;
 	}
 
+	if (db->db_level == 0) {
+		dnode_new_blkid(dn, db->db_blkid, tx, drop_struct_lock);
+		ASSERT(dn->dn_maxblkid >= db->db_blkid);
+	}
+
 	if (db->db_level+1 < dn->dn_nlevels) {
 		dmu_buf_impl_t *parent = db->db_parent;
 		dbuf_dirty_record_t *di;
@@ -1115,7 +1147,7 @@ dbuf_undirty(dmu_buf_impl_t *db, dmu_tx_t *tx)
 {
 	dnode_t *dn = db->db_dnode;
 	uint64_t txg = tx->tx_txg;
-	dbuf_dirty_record_t *dr;
+	dbuf_dirty_record_t *dr, **drp;
 
 	ASSERT(txg != 0);
 	ASSERT(db->db_blkid != DB_BONUS_BLKID);
@@ -1125,7 +1157,7 @@ dbuf_undirty(dmu_buf_impl_t *db, dmu_tx_t *tx)
 	/*
 	 * If this buffer is not dirty, we're done.
 	 */
-	for (dr = db->db_last_dirty; dr; dr = dr->dr_next)
+	for (drp = &db->db_last_dirty; (dr = *drp) != NULL; drp = &dr->dr_next)
 		if (dr->dr_txg <= txg)
 			break;
 	if (dr == NULL || dr->dr_txg < txg) {
@@ -1155,14 +1187,14 @@ dbuf_undirty(dmu_buf_impl_t *db, dmu_tx_t *tx)
 
 	/* XXX would be nice to fix up dn_towrite_space[] */
 
-	db->db_last_dirty = dr->dr_next;
+	*drp = dr->dr_next;
 
 	if (dr->dr_parent) {
 		mutex_enter(&dr->dr_parent->dt.di.dr_mtx);
 		list_remove(&dr->dr_parent->dt.di.dr_children, dr);
 		mutex_exit(&dr->dr_parent->dt.di.dr_mtx);
 	} else if (db->db_level+1 == dn->dn_nlevels) {
-		ASSERT3P(db->db_parent, ==, dn->dn_dbuf);
+		ASSERT(db->db_blkptr == NULL || db->db_parent == dn->dn_dbuf);
 		mutex_enter(&dn->dn_mtx);
 		list_remove(&dn->dn_dirty_records[txg & TXG_MASK], dr);
 		mutex_exit(&dn->dn_mtx);
@@ -1178,8 +1210,8 @@ dbuf_undirty(dmu_buf_impl_t *db, dmu_tx_t *tx)
 	} else {
 		ASSERT(db->db_buf != NULL);
 		ASSERT(list_head(&dr->dt.di.dr_children) == NULL);
-		list_destroy(&dr->dt.di.dr_children);
 		mutex_destroy(&dr->dt.di.dr_mtx);
+		list_destroy(&dr->dt.di.dr_children);
 	}
 	kmem_free(dr, sizeof (dbuf_dirty_record_t));
 
@@ -1204,7 +1236,7 @@ dbuf_undirty(dmu_buf_impl_t *db, dmu_tx_t *tx)
 void
 dbuf_will_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx)
 {
-	int rf = DB_RF_MUST_SUCCEED;
+	int rf = DB_RF_MUST_SUCCEED | DB_RF_NOPREFETCH;
 
 	ASSERT(tx->tx_txg != 0);
 	ASSERT(!refcount_is_zero(&db->db_holds));
@@ -1282,8 +1314,10 @@ dbuf_clear(dmu_buf_impl_t *db)
 
 	if (db->db_state == DB_CACHED) {
 		ASSERT(db->db.db_data != NULL);
-		if (db->db_blkid == DB_BONUS_BLKID)
+		if (db->db_blkid == DB_BONUS_BLKID) {
 			zio_buf_free(db->db.db_data, DN_MAX_BONUSLEN);
+			arc_space_return(DN_MAX_BONUSLEN);
+		}
 		db->db.db_data = NULL;
 		db->db_state = DB_UNCACHED;
 	}
@@ -1297,6 +1331,7 @@ dbuf_clear(dmu_buf_impl_t *db)
 	if (db->db_blkid != DB_BONUS_BLKID && MUTEX_HELD(&dn->dn_dbufs_mtx)) {
 		list_remove(&dn->dn_dbufs, db);
 		dnode_rele(dn, db);
+		db->db_dnode = NULL;
 	}
 
 	if (db->db_buf)
@@ -1397,10 +1432,13 @@ dbuf_create(dnode_t *dn, uint8_t level, uint64_t blkid,
 
 	if (blkid == DB_BONUS_BLKID) {
 		ASSERT3P(parent, ==, dn->dn_dbuf);
-		db->db.db_size = dn->dn_bonuslen;
+		db->db.db_size = DN_MAX_BONUSLEN -
+		    (dn->dn_nblkptr-1) * sizeof (blkptr_t);
+		ASSERT3U(db->db.db_size, >=, dn->dn_bonuslen);
 		db->db.db_offset = DB_BONUS_BLKID;
 		db->db_state = DB_UNCACHED;
 		/* the bonus dbuf is not placed in the hash table */
+		arc_space_consume(sizeof (dmu_buf_impl_t));
 		return (db);
 	} else {
 		int blocksize =
@@ -1427,6 +1465,7 @@ dbuf_create(dnode_t *dn, uint8_t level, uint64_t blkid,
 	list_insert_head(&dn->dn_dbufs, db);
 	db->db_state = DB_UNCACHED;
 	mutex_exit(&dn->dn_dbufs_mtx);
+	arc_space_consume(sizeof (dmu_buf_impl_t));
 
 	if (parent && parent != dn->dn_dbuf)
 		dbuf_add_ref(parent, db);
@@ -1469,31 +1508,33 @@ dbuf_destroy(dmu_buf_impl_t *db)
 	ASSERT(refcount_is_zero(&db->db_holds));
 
 	if (db->db_blkid != DB_BONUS_BLKID) {
-		dnode_t *dn = db->db_dnode;
-
 		/*
 		 * If this dbuf is still on the dn_dbufs list,
 		 * remove it from that list.
 		 */
-		if (list_link_active(&db->db_link)) {
+		if (db->db_dnode) {
+			dnode_t *dn = db->db_dnode;
+
 			mutex_enter(&dn->dn_dbufs_mtx);
 			list_remove(&dn->dn_dbufs, db);
 			mutex_exit(&dn->dn_dbufs_mtx);
 
 			dnode_rele(dn, db);
+			db->db_dnode = NULL;
 		}
 		dbuf_hash_remove(db);
 	}
 	db->db_parent = NULL;
-	db->db_dnode = NULL;
 	db->db_buf = NULL;
 
+	ASSERT(!list_link_active(&db->db_link));
 	ASSERT(db->db.db_data == NULL);
 	ASSERT(db->db_hash_next == NULL);
 	ASSERT(db->db_blkptr == NULL);
 	ASSERT(db->db_data_pending == NULL);
 
 	kmem_cache_free(dbuf_cache, db);
+	arc_space_return(sizeof (dmu_buf_impl_t));
 }
 
 void
@@ -1525,6 +1566,7 @@ dbuf_prefetch(dnode_t *dn, uint64_t blkid)
 
 	if (dbuf_findbp(dn, 0, blkid, TRUE, &db, &bp) == 0) {
 		if (bp && !BP_IS_HOLE(bp)) {
+			arc_buf_t *pbuf;
 			uint32_t aflags = ARC_NOWAIT | ARC_PREFETCH;
 			zbookmark_t zb;
 			zb.zb_objset = dn->dn_objset->os_dsl_dataset ?
@@ -1533,9 +1575,13 @@ dbuf_prefetch(dnode_t *dn, uint64_t blkid)
 			zb.zb_level = 0;
 			zb.zb_blkid = blkid;
 
-			(void) arc_read(NULL, dn->dn_objset->os_spa, bp,
-			    dmu_ot[dn->dn_type].ot_byteswap,
-			    NULL, NULL, ZIO_PRIORITY_ASYNC_READ,
+			if (db)
+				pbuf = db->db_buf;
+			else
+				pbuf = dn->dn_objset->os_phys_buf;
+
+			(void) arc_read(NULL, dn->dn_objset->os_spa,
+			    bp, pbuf, NULL, NULL, ZIO_PRIORITY_ASYNC_READ,
 			    ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE,
 			    &aflags, &zb);
 		}
@@ -1652,16 +1698,13 @@ dbuf_hold_level(dnode_t *dn, int level, uint64_t blkid, void *tag)
 	return (err ? NULL : db);
 }
 
-dmu_buf_impl_t *
+void
 dbuf_create_bonus(dnode_t *dn)
 {
-	dmu_buf_impl_t *db = dn->dn_bonus;
-
 	ASSERT(RW_WRITE_HELD(&dn->dn_struct_rwlock));
 
 	ASSERT(dn->dn_bonus == NULL);
-	db = dbuf_create(dn, 0, DB_BONUS_BLKID, dn->dn_dbuf, NULL);
-	return (db);
+	dn->dn_bonus = dbuf_create(dn, 0, DB_BONUS_BLKID, dn->dn_dbuf, NULL);
 }
 
 #pragma weak dmu_buf_add_ref = dbuf_add_ref
@@ -1716,7 +1759,10 @@ dbuf_rele(dmu_buf_impl_t *db, void *tag)
 			dbuf_evict(db);
 		} else {
 			VERIFY(arc_buf_remove_ref(db->db_buf, db) == 0);
-			mutex_exit(&db->db_mtx);
+			if (!DBUF_IS_CACHEABLE(db))
+				dbuf_clear(db);
+			else
+				mutex_exit(&db->db_mtx);
 		}
 	} else {
 		mutex_exit(&db->db_mtx);
@@ -1852,15 +1898,8 @@ dbuf_sync_indirect(dbuf_dirty_record_t *dr, dmu_tx_t *tx)
 
 	db->db_data_pending = dr;
 
-	arc_release(db->db_buf, db);
 	mutex_exit(&db->db_mtx);
-
-	/*
-	 * XXX -- we should design a compression algorithm
-	 * that specializes in arrays of bps.
-	 */
-	dbuf_write(dr, db->db_buf, ZIO_CHECKSUM_FLETCHER_4,
-	    zfs_mdcomp_disable ? ZIO_COMPRESS_EMPTY : ZIO_COMPRESS_LZJB, tx);
+	dbuf_write(dr, db->db_buf, tx);
 
 	zio = dr->dr_zio;
 	mutex_enter(&dr->dt.di.dr_mtx);
@@ -1878,7 +1917,6 @@ dbuf_sync_leaf(dbuf_dirty_record_t *dr, dmu_tx_t *tx)
 	dnode_t *dn = db->db_dnode;
 	objset_impl_t *os = dn->dn_objset;
 	uint64_t txg = tx->tx_txg;
-	int checksum, compress;
 	int blksz;
 
 	ASSERT(dmu_tx_is_syncing(tx));
@@ -1909,23 +1947,21 @@ dbuf_sync_leaf(dbuf_dirty_record_t *dr, dmu_tx_t *tx)
 	 */
 	if (db->db_blkid == DB_BONUS_BLKID) {
 		dbuf_dirty_record_t **drp;
-		/*
-		 * Use dn_phys->dn_bonuslen since db.db_size is the length
-		 * of the bonus buffer in the open transaction rather than
-		 * the syncing transaction.
-		 */
+
 		ASSERT(*datap != NULL);
 		ASSERT3U(db->db_level, ==, 0);
 		ASSERT3U(dn->dn_phys->dn_bonuslen, <=, DN_MAX_BONUSLEN);
 		bcopy(*datap, DN_BONUS(dn->dn_phys), dn->dn_phys->dn_bonuslen);
-		if (*datap != db->db.db_data)
+		if (*datap != db->db.db_data) {
 			zio_buf_free(*datap, DN_MAX_BONUSLEN);
+			arc_space_return(DN_MAX_BONUSLEN);
+		}
 		db->db_data_pending = NULL;
 		drp = &db->db_last_dirty;
 		while (*drp != dr)
 			drp = &(*drp)->dr_next;
-		ASSERT((*drp)->dr_next == NULL);
-		*drp = NULL;
+		ASSERT(dr->dr_next == NULL);
+		*drp = dr->dr_next;
 		if (dr->dr_dbuf->db_level != 0) {
 			list_destroy(&dr->dt.di.dr_children);
 			mutex_destroy(&dr->dt.di.dr_mtx);
@@ -1939,6 +1975,14 @@ dbuf_sync_leaf(dbuf_dirty_record_t *dr, dmu_tx_t *tx)
 	}
 
 	/*
+	 * This function may have dropped the db_mtx lock allowing a dmu_sync
+	 * operation to sneak in. As a result, we need to ensure that we
+	 * don't check the dr_override_state until we have returned from
+	 * dbuf_check_blkptr.
+	 */
+	dbuf_check_blkptr(dn, db);
+
+	/*
 	 * If this buffer is in the middle of an immdiate write,
 	 * wait for the synchronous IO to complete.
 	 */
@@ -1948,8 +1992,6 @@ dbuf_sync_leaf(dbuf_dirty_record_t *dr, dmu_tx_t *tx)
 		ASSERT(dr->dt.dl.dr_override_state != DR_NOT_OVERRIDDEN);
 	}
 
-	dbuf_check_blkptr(dn, db);
-
 	/*
 	 * If this dbuf has already been written out via an immediate write,
 	 * just complete the write by copying over the new block pointer and
@@ -1963,6 +2005,7 @@ dbuf_sync_leaf(dbuf_dirty_record_t *dr, dmu_tx_t *tx)
 		zio_fake.io_bp = db->db_blkptr;
 		zio_fake.io_bp_orig = *db->db_blkptr;
 		zio_fake.io_txg = txg;
+		zio_fake.io_flags = 0;
 
 		*db->db_blkptr = dr->dt.dl.dr_overridden_by;
 		dr->dt.dl.dr_override_state = DR_NOT_OVERRIDDEN;
@@ -1970,8 +2013,12 @@ dbuf_sync_leaf(dbuf_dirty_record_t *dr, dmu_tx_t *tx)
 		dr->dr_zio = &zio_fake;
 		mutex_exit(&db->db_mtx);
 
+		ASSERT(!DVA_EQUAL(BP_IDENTITY(zio_fake.io_bp),
+		    BP_IDENTITY(&zio_fake.io_bp_orig)) ||
+		    BP_IS_HOLE(zio_fake.io_bp));
+
 		if (BP_IS_OLDER(&zio_fake.io_bp_orig, txg))
-			dsl_dataset_block_kill(os->os_dsl_dataset,
+			(void) dsl_dataset_block_kill(os->os_dsl_dataset,
 			    &zio_fake.io_bp_orig, dn->dn_zio, tx);
 
 		dbuf_write_ready(&zio_fake, db->db_buf, db);
@@ -1997,14 +2044,6 @@ dbuf_sync_leaf(dbuf_dirty_record_t *dr, dmu_tx_t *tx)
 			*datap = arc_buf_alloc(os->os_spa, blksz, db, type);
 			bcopy(db->db.db_data, (*datap)->b_data, blksz);
 		}
-	} else {
-		/*
-		 * Private object buffers are released here rather
-		 * than in dbuf_dirty() since they are only modified
-		 * in the syncing context and we don't want the
-		 * overhead of making multiple copies of the data.
-		 */
-		arc_release(db->db_buf, db);
 	}
 
 	ASSERT(*datap != NULL);
@@ -2012,22 +2051,7 @@ dbuf_sync_leaf(dbuf_dirty_record_t *dr, dmu_tx_t *tx)
 
 	mutex_exit(&db->db_mtx);
 
-	/*
-	 * Allow dnode settings to override objset settings,
-	 * except for metadata checksums.
-	 */
-	if (dmu_ot[dn->dn_type].ot_metadata) {
-		checksum = os->os_md_checksum;
-		compress = zio_compress_select(dn->dn_compress,
-		    os->os_md_compress);
-	} else {
-		checksum = zio_checksum_select(dn->dn_checksum,
-		    os->os_checksum);
-		compress = zio_compress_select(dn->dn_compress,
-		    os->os_compress);
-	}
-
-	dbuf_write(dr, *datap, checksum, compress, tx);
+	dbuf_write(dr, *datap, tx);
 
 	ASSERT(!list_link_active(&dr->dr_dirty_node));
 	if (dn->dn_object == DMU_META_DNODE_OBJECT)
@@ -2063,8 +2087,7 @@ dbuf_sync_list(list_t *list, dmu_tx_t *tx)
 }
 
 static void
-dbuf_write(dbuf_dirty_record_t *dr, arc_buf_t *data, int checksum,
-    int compress, dmu_tx_t *tx)
+dbuf_write(dbuf_dirty_record_t *dr, arc_buf_t *data, dmu_tx_t *tx)
 {
 	dmu_buf_impl_t *db = dr->dr_dbuf;
 	dnode_t *dn = db->db_dnode;
@@ -2072,8 +2095,23 @@ dbuf_write(dbuf_dirty_record_t *dr, arc_buf_t *data, int checksum,
 	dmu_buf_impl_t *parent = db->db_parent;
 	uint64_t txg = tx->tx_txg;
 	zbookmark_t zb;
+	writeprops_t wp = { 0 };
 	zio_t *zio;
-	int zio_flags;
+
+	if (!BP_IS_HOLE(db->db_blkptr) &&
+	    (db->db_level > 0 || dn->dn_type == DMU_OT_DNODE)) {
+		/*
+		 * Private object buffers are released here rather
+		 * than in dbuf_dirty() since they are only modified
+		 * in the syncing context and we don't want the
+		 * overhead of making multiple copies of the data.
+		 */
+		arc_release(data, db);
+	} else {
+		ASSERT(arc_released(data));
+		/* XXX why do we need to thaw here? */
+		arc_buf_thaw(data);
+	}
 
 	if (parent != dn->dn_dbuf) {
 		ASSERT(parent && parent->db_data_pending);
@@ -2096,17 +2134,22 @@ dbuf_write(dbuf_dirty_record_t *dr, arc_buf_t *data, int checksum,
 	zb.zb_level = db->db_level;
 	zb.zb_blkid = db->db_blkid;
 
-	zio_flags = ZIO_FLAG_MUSTSUCCEED;
-	if (dmu_ot[dn->dn_type].ot_metadata || zb.zb_level != 0)
-		zio_flags |= ZIO_FLAG_METADATA;
+	wp.wp_type = dn->dn_type;
+	wp.wp_level = db->db_level;
+	wp.wp_copies = os->os_copies;
+	wp.wp_dncompress = dn->dn_compress;
+	wp.wp_oscompress = os->os_compress;
+	wp.wp_dnchecksum = dn->dn_checksum;
+	wp.wp_oschecksum = os->os_checksum;
+
 	if (BP_IS_OLDER(db->db_blkptr, txg))
-		dsl_dataset_block_kill(
+		(void) dsl_dataset_block_kill(
 		    os->os_dsl_dataset, db->db_blkptr, zio, tx);
 
-	dr->dr_zio = arc_write(zio, os->os_spa, checksum, compress,
-	    dmu_get_replication_level(os, &zb, dn->dn_type), txg,
-	    db->db_blkptr, data, dbuf_write_ready, dbuf_write_done, db,
-	    ZIO_PRIORITY_ASYNC_WRITE, zio_flags, &zb);
+	dr->dr_zio = arc_write(zio, os->os_spa, &wp,
+	    DBUF_IS_L2CACHEABLE(db), txg, db->db_blkptr,
+	    data, dbuf_write_ready, dbuf_write_done, db,
+	    ZIO_PRIORITY_ASYNC_WRITE, ZIO_FLAG_MUSTSUCCEED, &zb);
 }
 
 /* ARGSUSED */
@@ -2116,27 +2159,33 @@ dbuf_write_ready(zio_t *zio, arc_buf_t *buf, void *vdb)
 	dmu_buf_impl_t *db = vdb;
 	dnode_t *dn = db->db_dnode;
 	objset_impl_t *os = dn->dn_objset;
+	blkptr_t *bp = zio->io_bp;
 	blkptr_t *bp_orig = &zio->io_bp_orig;
 	uint64_t fill = 0;
 	int old_size, new_size, i;
 
+	ASSERT(db->db_blkptr == bp);
+
 	dprintf_dbuf_bp(db, bp_orig, "bp_orig: %s", "");
 
 	old_size = bp_get_dasize(os->os_spa, bp_orig);
-	new_size = bp_get_dasize(os->os_spa, zio->io_bp);
+	new_size = bp_get_dasize(os->os_spa, bp);
 
-	dnode_diduse_space(dn, new_size-old_size);
+	dnode_diduse_space(dn, new_size - old_size);
 
-	if (BP_IS_HOLE(zio->io_bp)) {
+	if (BP_IS_HOLE(bp)) {
 		dsl_dataset_t *ds = os->os_dsl_dataset;
 		dmu_tx_t *tx = os->os_synctx;
 
 		if (bp_orig->blk_birth == tx->tx_txg)
-			dsl_dataset_block_kill(ds, bp_orig, NULL, tx);
-		ASSERT3U(db->db_blkptr->blk_fill, ==, 0);
+			(void) dsl_dataset_block_kill(ds, bp_orig, zio, tx);
+		ASSERT3U(bp->blk_fill, ==, 0);
 		return;
 	}
 
+	ASSERT(BP_GET_TYPE(bp) == dn->dn_type);
+	ASSERT(BP_GET_LEVEL(bp) == db->db_level);
+
 	mutex_enter(&db->db_mtx);
 
 	if (db->db_level == 0) {
@@ -2156,32 +2205,31 @@ dbuf_write_ready(zio_t *zio, arc_buf_t *buf, void *vdb)
 			fill = 1;
 		}
 	} else {
-		blkptr_t *bp = db->db.db_data;
+		blkptr_t *ibp = db->db.db_data;
 		ASSERT3U(db->db.db_size, ==, 1<<dn->dn_phys->dn_indblkshift);
-		for (i = db->db.db_size >> SPA_BLKPTRSHIFT; i > 0; i--, bp++) {
-			if (BP_IS_HOLE(bp))
+		for (i = db->db.db_size >> SPA_BLKPTRSHIFT; i > 0; i--, ibp++) {
+			if (BP_IS_HOLE(ibp))
 				continue;
-			ASSERT3U(BP_GET_LSIZE(bp), ==,
+			ASSERT3U(BP_GET_LSIZE(ibp), ==,
 			    db->db_level == 1 ? dn->dn_datablksz :
 			    (1<<dn->dn_phys->dn_indblkshift));
-			fill += bp->blk_fill;
+			fill += ibp->blk_fill;
 		}
 	}
 
-	db->db_blkptr->blk_fill = fill;
-	BP_SET_TYPE(db->db_blkptr, dn->dn_type);
-	BP_SET_LEVEL(db->db_blkptr, db->db_level);
+	bp->blk_fill = fill;
 
 	mutex_exit(&db->db_mtx);
 
-	/* We must do this after we've set the bp's type and level */
-	if (!DVA_EQUAL(BP_IDENTITY(zio->io_bp), BP_IDENTITY(bp_orig))) {
+	if (zio->io_flags & ZIO_FLAG_IO_REWRITE) {
+		ASSERT(DVA_EQUAL(BP_IDENTITY(bp), BP_IDENTITY(bp_orig)));
+	} else {
 		dsl_dataset_t *ds = os->os_dsl_dataset;
 		dmu_tx_t *tx = os->os_synctx;
 
 		if (bp_orig->blk_birth == tx->tx_txg)
-			dsl_dataset_block_kill(ds, bp_orig, NULL, tx);
-		dsl_dataset_block_born(ds, zio->io_bp, tx);
+			(void) dsl_dataset_block_kill(ds, bp_orig, zio, tx);
+		dsl_dataset_block_born(ds, bp, tx);
 	}
 }
 
@@ -2198,13 +2246,12 @@ dbuf_write_done(zio_t *zio, arc_buf_t *buf, void *vdb)
 	mutex_enter(&db->db_mtx);
 
 	drp = &db->db_last_dirty;
-	while (*drp != db->db_data_pending)
-		drp = &(*drp)->dr_next;
-	ASSERT(!list_link_active(&(*drp)->dr_dirty_node));
-	ASSERT((*drp)->dr_txg == txg);
-	ASSERT((*drp)->dr_next == NULL);
-	dr = *drp;
-	*drp = NULL;
+	while ((dr = *drp) != db->db_data_pending)
+		drp = &dr->dr_next;
+	ASSERT(!list_link_active(&dr->dr_dirty_node));
+	ASSERT(dr->dr_txg == txg);
+	ASSERT(dr->dr_next == NULL);
+	*drp = dr->dr_next;
 
 	if (db->db_level == 0) {
 		ASSERT(db->db_blkid != DB_BONUS_BLKID);
@@ -2230,8 +2277,8 @@ dbuf_write_done(zio_t *zio, arc_buf_t *buf, void *vdb)
 			    >> (db->db_level * epbs), >=, db->db_blkid);
 			arc_set_callback(db->db_buf, dbuf_do_evict, db);
 		}
-		list_destroy(&dr->dt.di.dr_children);
 		mutex_destroy(&dr->dt.di.dr_mtx);
+		list_destroy(&dr->dt.di.dr_children);
 	}
 	kmem_free(dr, sizeof (dbuf_dirty_record_t));
 
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu.c
index d3be6b4ff22e..377efb9d105e 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu.c
@@ -19,12 +19,10 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
-#pragma ident	"%Z%%M%	%I%	%E% SMI"
-
 #include <sys/dmu.h>
 #include <sys/dmu_impl.h>
 #include <sys/dmu_tx.h>
@@ -42,6 +40,7 @@
 #include <sys/zfs_ioctl.h>
 #include <sys/zap.h>
 #include <sys/zio_checksum.h>
+#include <sys/zfs_znode.h>
 
 const dmu_object_type_info_t dmu_ot[DMU_OT_NUMTYPES] = {
 	{	byteswap_uint8_array,	TRUE,	"unallocated"		},
@@ -62,7 +61,7 @@ const dmu_object_type_info_t dmu_ot[DMU_OT_NUMTYPES] = {
 	{	zap_byteswap,		TRUE,	"DSL props"		},
 	{	byteswap_uint64_array,	TRUE,	"DSL dataset"		},
 	{	zfs_znode_byteswap,	TRUE,	"ZFS znode"		},
-	{	zfs_acl_byteswap,	TRUE,	"ZFS ACL"		},
+	{	zfs_oldacl_byteswap,	TRUE,	"ZFS V0 ACL"		},
 	{	byteswap_uint8_array,	FALSE,	"ZFS plain file"	},
 	{	zap_byteswap,		TRUE,	"ZFS directory"		},
 	{	zap_byteswap,		TRUE,	"ZFS master node"	},
@@ -75,7 +74,14 @@ const dmu_object_type_info_t dmu_ot[DMU_OT_NUMTYPES] = {
 	{	zap_byteswap,		TRUE,	"persistent error log"	},
 	{	byteswap_uint8_array,	TRUE,	"SPA history"		},
 	{	byteswap_uint64_array,	TRUE,	"SPA history offsets"	},
-	{	zap_byteswap,	TRUE,	"Pool properties"	},
+	{	zap_byteswap,		TRUE,	"Pool properties"	},
+	{	zap_byteswap,		TRUE,	"DSL permissions"	},
+	{	zfs_acl_byteswap,	TRUE,	"ZFS ACL"		},
+	{	byteswap_uint8_array,	TRUE,	"ZFS SYSACL"		},
+	{	byteswap_uint8_array,	TRUE,	"FUID table"		},
+	{	byteswap_uint64_array,	TRUE,	"FUID table size"	},
+	{	zap_byteswap,		TRUE,	"DSL dataset next clones"},
+	{	zap_byteswap,		TRUE,	"scrub work queue"	},
 };
 
 int
@@ -115,6 +121,19 @@ dmu_bonus_max(void)
 	return (DN_MAX_BONUSLEN);
 }
 
+int
+dmu_set_bonus(dmu_buf_t *db, int newsize, dmu_tx_t *tx)
+{
+	dnode_t *dn = ((dmu_buf_impl_t *)db)->db_dnode;
+
+	if (dn->dn_bonus != (dmu_buf_impl_t *)db)
+		return (EINVAL);
+	if (newsize < 0 || newsize > db->db_size)
+		return (EINVAL);
+	dnode_setbonuslen(dn, newsize, tx);
+	return (0);
+}
+
 /*
  * returns ENOENT, EIO, or 0.
  */
@@ -122,27 +141,27 @@ int
 dmu_bonus_hold(objset_t *os, uint64_t object, void *tag, dmu_buf_t **dbp)
 {
 	dnode_t *dn;
-	int err, count;
 	dmu_buf_impl_t *db;
+	int error;
 
-	err = dnode_hold(os->os, object, FTAG, &dn);
-	if (err)
-		return (err);
+	error = dnode_hold(os->os, object, FTAG, &dn);
+	if (error)
+		return (error);
 
 	rw_enter(&dn->dn_struct_rwlock, RW_READER);
 	if (dn->dn_bonus == NULL) {
 		rw_exit(&dn->dn_struct_rwlock);
 		rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
 		if (dn->dn_bonus == NULL)
-			dn->dn_bonus = dbuf_create_bonus(dn);
+			dbuf_create_bonus(dn);
 	}
 	db = dn->dn_bonus;
 	rw_exit(&dn->dn_struct_rwlock);
-	mutex_enter(&db->db_mtx);
-	count = refcount_add(&db->db_holds, tag);
-	mutex_exit(&db->db_mtx);
-	if (count == 1)
-		dnode_add_ref(dn, db);
+
+	/* as long as the bonus buf is held, the dnode will be held */
+	if (refcount_add(&db->db_holds, tag) == 1)
+		VERIFY(dnode_add_ref(dn, db));
+
 	dnode_rele(dn, FTAG);
 
 	VERIFY(0 == dbuf_read(db, NULL, DB_RF_MUST_SUCCEED));
@@ -161,11 +180,13 @@ static int
 dmu_buf_hold_array_by_dnode(dnode_t *dn, uint64_t offset,
     uint64_t length, int read, void *tag, int *numbufsp, dmu_buf_t ***dbpp)
 {
+	dsl_pool_t *dp = NULL;
 	dmu_buf_t **dbp;
 	uint64_t blkid, nblks, i;
 	uint32_t flags;
 	int err;
 	zio_t *zio;
+	hrtime_t start;
 
 	ASSERT(length <= DMU_MAX_ACCESS);
 
@@ -192,7 +213,11 @@ dmu_buf_hold_array_by_dnode(dnode_t *dn, uint64_t offset,
 	}
 	dbp = kmem_zalloc(sizeof (dmu_buf_t *) * nblks, KM_SLEEP);
 
-	zio = zio_root(dn->dn_objset->os_spa, NULL, NULL, TRUE);
+	if (dn->dn_objset->os_dsl_dataset)
+		dp = dn->dn_objset->os_dsl_dataset->ds_dir->dd_pool;
+	if (dp && dsl_pool_sync_context(dp))
+		start = gethrtime();
+	zio = zio_root(dn->dn_objset->os_spa, NULL, NULL, ZIO_FLAG_CANFAIL);
 	blkid = dbuf_whichblock(dn, offset);
 	for (i = 0; i < nblks; i++) {
 		dmu_buf_impl_t *db = dbuf_hold(dn, blkid+i, tag);
@@ -214,6 +239,9 @@ dmu_buf_hold_array_by_dnode(dnode_t *dn, uint64_t offset,
 
 	/* wait for async i/o */
 	err = zio_wait(zio);
+	/* track read overhead when we are in sync context */
+	if (dp && dsl_pool_sync_context(dp))
+		dp->dp_read_overhead += gethrtime() - start;
 	if (err) {
 		dmu_buf_rele_array(dbp, nblks, tag);
 		return (err);
@@ -343,6 +371,155 @@ dmu_prefetch(objset_t *os, uint64_t object, uint64_t offset, uint64_t len)
 	dnode_rele(dn, FTAG);
 }
 
+static int
+get_next_chunk(dnode_t *dn, uint64_t *offset, uint64_t limit)
+{
+	uint64_t len = *offset - limit;
+	uint64_t chunk_len = dn->dn_datablksz * DMU_MAX_DELETEBLKCNT;
+	uint64_t subchunk =
+	    dn->dn_datablksz * EPB(dn->dn_indblkshift, SPA_BLKPTRSHIFT);
+
+	ASSERT(limit <= *offset);
+
+	if (len <= chunk_len) {
+		*offset = limit;
+		return (0);
+	}
+
+	ASSERT(ISP2(subchunk));
+
+	while (*offset > limit) {
+		uint64_t initial_offset = P2ROUNDUP(*offset, subchunk);
+		uint64_t delta;
+		int err;
+
+		/* skip over allocated data */
+		err = dnode_next_offset(dn,
+		    DNODE_FIND_HOLE|DNODE_FIND_BACKWARDS, offset, 1, 1, 0);
+		if (err == ESRCH)
+			*offset = limit;
+		else if (err)
+			return (err);
+
+		ASSERT3U(*offset, <=, initial_offset);
+		*offset = P2ALIGN(*offset, subchunk);
+		delta = initial_offset - *offset;
+		if (delta >= chunk_len) {
+			*offset += delta - chunk_len;
+			return (0);
+		}
+		chunk_len -= delta;
+
+		/* skip over unallocated data */
+		err = dnode_next_offset(dn,
+		    DNODE_FIND_BACKWARDS, offset, 1, 1, 0);
+		if (err == ESRCH)
+			*offset = limit;
+		else if (err)
+			return (err);
+
+		if (*offset < limit)
+			*offset = limit;
+		ASSERT3U(*offset, <, initial_offset);
+	}
+	return (0);
+}
+
+static int
+dmu_free_long_range_impl(objset_t *os, dnode_t *dn, uint64_t offset,
+    uint64_t length, boolean_t free_dnode)
+{
+	dmu_tx_t *tx;
+	uint64_t object_size, start, end, len;
+	boolean_t trunc = (length == DMU_OBJECT_END);
+	int align, err;
+
+	align = 1 << dn->dn_datablkshift;
+	ASSERT(align > 0);
+	object_size = align == 1 ? dn->dn_datablksz :
+	    (dn->dn_maxblkid + 1) << dn->dn_datablkshift;
+
+	if (trunc || (end = offset + length) > object_size)
+		end = object_size;
+	if (end <= offset)
+		return (0);
+	length = end - offset;
+
+	while (length) {
+		start = end;
+		err = get_next_chunk(dn, &start, offset);
+		if (err)
+			return (err);
+		len = trunc ? DMU_OBJECT_END : end - start;
+
+		tx = dmu_tx_create(os);
+		dmu_tx_hold_free(tx, dn->dn_object, start, len);
+		err = dmu_tx_assign(tx, TXG_WAIT);
+		if (err) {
+			dmu_tx_abort(tx);
+			return (err);
+		}
+
+		dnode_free_range(dn, start, trunc ? -1 : len, tx);
+
+		if (start == 0 && free_dnode) {
+			ASSERT(trunc);
+			dnode_free(dn, tx);
+		}
+
+		length -= end - start;
+
+		dmu_tx_commit(tx);
+		end = start;
+	}
+	return (0);
+}
+
+int
+dmu_free_long_range(objset_t *os, uint64_t object,
+    uint64_t offset, uint64_t length)
+{
+	dnode_t *dn;
+	int err;
+
+	err = dnode_hold(os->os, object, FTAG, &dn);
+	if (err != 0)
+		return (err);
+	err = dmu_free_long_range_impl(os, dn, offset, length, FALSE);
+	dnode_rele(dn, FTAG);
+	return (err);
+}
+
+int
+dmu_free_object(objset_t *os, uint64_t object)
+{
+	dnode_t *dn;
+	dmu_tx_t *tx;
+	int err;
+
+	err = dnode_hold_impl(os->os, object, DNODE_MUST_BE_ALLOCATED,
+	    FTAG, &dn);
+	if (err != 0)
+		return (err);
+	if (dn->dn_nlevels == 1) {
+		tx = dmu_tx_create(os);
+		dmu_tx_hold_bonus(tx, object);
+		dmu_tx_hold_free(tx, dn->dn_object, 0, DMU_OBJECT_END);
+		err = dmu_tx_assign(tx, TXG_WAIT);
+		if (err == 0) {
+			dnode_free_range(dn, 0, DMU_OBJECT_END, tx);
+			dnode_free(dn, tx);
+			dmu_tx_commit(tx);
+		} else {
+			dmu_tx_abort(tx);
+		}
+	} else {
+		err = dmu_free_long_range_impl(os, dn, 0, DMU_OBJECT_END, TRUE);
+	}
+	dnode_rele(dn, FTAG);
+	return (err);
+}
+
 int
 dmu_free_range(objset_t *os, uint64_t object, uint64_t offset,
     uint64_t size, dmu_tx_t *tx)
@@ -384,7 +561,6 @@ dmu_read(objset_t *os, uint64_t object, uint64_t offset, uint64_t size,
 
 	while (size > 0) {
 		uint64_t mylen = MIN(size, DMU_MAX_ACCESS / 2);
-		int err;
 
 		/*
 		 * NB: we could do this block-at-a-time, but it's nice
@@ -393,7 +569,7 @@ dmu_read(objset_t *os, uint64_t object, uint64_t offset, uint64_t size,
 		err = dmu_buf_hold_array_by_dnode(dn, offset, mylen,
 		    TRUE, FTAG, &numbufs, &dbp);
 		if (err)
-			return (err);
+			break;
 
 		for (i = 0; i < numbufs; i++) {
 			int tocpy;
@@ -414,7 +590,7 @@ dmu_read(objset_t *os, uint64_t object, uint64_t offset, uint64_t size,
 		dmu_buf_rele_array(dbp, numbufs, FTAG);
 	}
 	dnode_rele(dn, FTAG);
-	return (0);
+	return (err);
 }
 
 void
@@ -590,9 +766,9 @@ dmu_write_pages(objset_t *os, uint64_t object, uint64_t offset, uint64_t size,
 		for (copied = 0; copied < tocpy; copied += PAGESIZE) {
 			ASSERT3U(pp->p_offset, ==, db->db_offset + bufoff);
 			thiscpy = MIN(PAGESIZE, tocpy - copied);
-			va = ppmapin(pp, PROT_READ, (caddr_t)-1);
+			va = zfs_map_page(pp, S_READ);
 			bcopy(va, (char *)db->db_data + bufoff, thiscpy);
-			ppmapout(va);
+			zfs_unmap_page(pp, va);
 			pp = pp->p_next;
 			bufoff += PAGESIZE;
 		}
@@ -620,6 +796,22 @@ typedef struct {
 
 /* ARGSUSED */
 static void
+dmu_sync_ready(zio_t *zio, arc_buf_t *buf, void *varg)
+{
+	blkptr_t *bp = zio->io_bp;
+
+	if (!BP_IS_HOLE(bp)) {
+		dmu_sync_arg_t *in = varg;
+		dbuf_dirty_record_t *dr = in->dr;
+		dmu_buf_impl_t *db = dr->dr_dbuf;
+		ASSERT(BP_GET_TYPE(bp) == db->db_dnode->dn_type);
+		ASSERT(BP_GET_LEVEL(bp) == 0);
+		bp->blk_fill = 1;
+	}
+}
+
+/* ARGSUSED */
+static void
 dmu_sync_done(zio_t *zio, arc_buf_t *buf, void *varg)
 {
 	dmu_sync_arg_t *in = varg;
@@ -627,12 +819,6 @@ dmu_sync_done(zio_t *zio, arc_buf_t *buf, void *varg)
 	dmu_buf_impl_t *db = dr->dr_dbuf;
 	dmu_sync_cb_t *done = in->done;
 
-	if (!BP_IS_HOLE(zio->io_bp)) {
-		zio->io_bp->blk_fill = 1;
-		BP_SET_TYPE(zio->io_bp, db->db_dnode->dn_type);
-		BP_SET_LEVEL(zio->io_bp, 0);
-	}
-
 	mutex_enter(&db->db_mtx);
 	ASSERT(dr->dt.dl.dr_override_state == DR_IN_DMU_SYNC);
 	dr->dt.dl.dr_overridden_by = *zio->io_bp; /* structure assignment */
@@ -679,14 +865,13 @@ dmu_sync(zio_t *pio, dmu_buf_t *db_fake,
 	dbuf_dirty_record_t *dr;
 	dmu_sync_arg_t *in;
 	zbookmark_t zb;
+	writeprops_t wp = { 0 };
 	zio_t *zio;
-	int zio_flags;
 	int err;
 
 	ASSERT(BP_IS_HOLE(bp));
 	ASSERT(txg != 0);
 
-
 	dprintf("dmu_sync txg=%llu, s,o,q %llu %llu %llu\n",
 	    txg, tx->tx_synced_txg, tx->tx_open_txg, tx->tx_quiesced_txg);
 
@@ -791,15 +976,20 @@ dmu_sync(zio_t *pio, dmu_buf_t *db_fake,
 	zb.zb_object = db->db.db_object;
 	zb.zb_level = db->db_level;
 	zb.zb_blkid = db->db_blkid;
-	zio_flags = ZIO_FLAG_MUSTSUCCEED;
-	if (dmu_ot[db->db_dnode->dn_type].ot_metadata || zb.zb_level != 0)
-		zio_flags |= ZIO_FLAG_METADATA;
-	zio = arc_write(pio, os->os_spa,
-	    zio_checksum_select(db->db_dnode->dn_checksum, os->os_checksum),
-	    zio_compress_select(db->db_dnode->dn_compress, os->os_compress),
-	    dmu_get_replication_level(os, &zb, db->db_dnode->dn_type),
-	    txg, bp, dr->dt.dl.dr_data, NULL, dmu_sync_done, in,
-	    ZIO_PRIORITY_SYNC_WRITE, zio_flags, &zb);
+
+	wp.wp_type = db->db_dnode->dn_type;
+	wp.wp_level = db->db_level;
+	wp.wp_copies = os->os_copies;
+	wp.wp_dnchecksum = db->db_dnode->dn_checksum;
+	wp.wp_oschecksum = os->os_checksum;
+	wp.wp_dncompress = db->db_dnode->dn_compress;
+	wp.wp_oscompress = os->os_compress;
+
+	ASSERT(BP_IS_HOLE(bp));
+
+	zio = arc_write(pio, os->os_spa, &wp, DBUF_IS_L2CACHEABLE(db),
+	    txg, bp, dr->dt.dl.dr_data, dmu_sync_ready, dmu_sync_done, in,
+	    ZIO_PRIORITY_SYNC_WRITE, ZIO_FLAG_MUSTSUCCEED, &zb);
 
 	if (pio) {
 		zio_nowait(zio);
@@ -855,21 +1045,6 @@ dmu_object_set_compress(objset_t *os, uint64_t object, uint8_t compress,
 }
 
 int
-dmu_get_replication_level(objset_impl_t *os,
-    zbookmark_t *zb, dmu_object_type_t ot)
-{
-	int ncopies = os->os_copies;
-
-	/* If it's the mos, it should have max copies set. */
-	ASSERT(zb->zb_objset != 0 ||
-	    ncopies == spa_max_replication(os->os_spa));
-
-	if (dmu_ot[ot].ot_metadata || zb->zb_level != 0)
-		ncopies++;
-	return (MIN(ncopies, spa_max_replication(os->os_spa)));
-}
-
-int
 dmu_offset_next(objset_t *os, uint64_t object, boolean_t hole, uint64_t *off)
 {
 	dnode_t *dn;
@@ -894,7 +1069,7 @@ dmu_offset_next(objset_t *os, uint64_t object, boolean_t hole, uint64_t *off)
 			return (err);
 	}
 
-	err = dnode_next_offset(dn, hole, off, 1, 1, 0);
+	err = dnode_next_offset(dn, (hole ? DNODE_FIND_HOLE : 0), off, 1, 1, 0);
 	dnode_rele(dn, FTAG);
 
 	return (err);
@@ -1018,6 +1193,7 @@ dmu_init(void)
 	dbuf_init();
 	dnode_init();
 	arc_init();
+	l2arc_init();
 }
 
 void
@@ -1026,4 +1202,5 @@ dmu_fini(void)
 	arc_fini();
 	dnode_fini();
 	dbuf_fini();
+	l2arc_fini();
 }
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_object.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_object.c
index 93168cc8901f..1b9247d66e65 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_object.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_object.c
@@ -19,7 +19,7 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
@@ -54,7 +54,8 @@ dmu_object_alloc(objset_t *os, dmu_object_type_t ot, int blocksize,
 		if (P2PHASE(object, L2_dnode_count) == 0) {
 			uint64_t offset = restarted ? object << DNODE_SHIFT : 0;
 			int error = dnode_next_offset(osi->os_meta_dnode,
-			    B_TRUE, &offset, 2, DNODES_PER_BLOCK >> 2, 0);
+			    DNODE_FIND_HOLE,
+			    &offset, 2, DNODES_PER_BLOCK >> 2, 0);
 			restarted = B_TRUE;
 			if (error == 0)
 				object = offset >> DNODE_SHIFT;
@@ -139,6 +140,7 @@ dmu_object_free(objset_t *os, uint64_t object, dmu_tx_t *tx)
 		return (err);
 
 	ASSERT(dn->dn_type != DMU_OT_NONE);
+	dnode_free_range(dn, 0, DMU_OBJECT_END, tx);
 	dnode_free(dn, tx);
 	dnode_rele(dn, FTAG);
 
@@ -152,7 +154,7 @@ dmu_object_next(objset_t *os, uint64_t *objectp, boolean_t hole, uint64_t txg)
 	int error;
 
 	error = dnode_next_offset(os->os->os_meta_dnode,
-	    hole, &offset, 0, DNODES_PER_BLOCK, txg);
+	    (hole ? DNODE_FIND_HOLE : 0), &offset, 0, DNODES_PER_BLOCK, txg);
 
 	*objectp = offset >> DNODE_SHIFT;
 
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_objset.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_objset.c
index 378fe8c15bc0..7981e06825c4 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_objset.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_objset.c
@@ -19,12 +19,11 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
-#pragma ident	"%Z%%M%	%I%	%E% SMI"
-
+#include <sys/cred.h>
 #include <sys/zfs_context.h>
 #include <sys/dmu_objset.h>
 #include <sys/dsl_dir.h>
@@ -32,6 +31,7 @@
 #include <sys/dsl_prop.h>
 #include <sys/dsl_pool.h>
 #include <sys/dsl_synctask.h>
+#include <sys/dsl_deleg.h>
 #include <sys/dnode.h>
 #include <sys/dbuf.h>
 #include <sys/zvol.h>
@@ -40,7 +40,7 @@
 #include <sys/zap.h>
 #include <sys/zil.h>
 #include <sys/dmu_impl.h>
-
+#include <sys/zfs_ioctl.h>
 
 spa_t *
 dmu_objset_spa(objset_t *os)
@@ -131,6 +131,34 @@ copies_changed_cb(void *arg, uint64_t newval)
 	osi->os_copies = newval;
 }
 
+static void
+primary_cache_changed_cb(void *arg, uint64_t newval)
+{
+	objset_impl_t *osi = arg;
+
+	/*
+	 * Inheritance and range checking should have been done by now.
+	 */
+	ASSERT(newval == ZFS_CACHE_ALL || newval == ZFS_CACHE_NONE ||
+	    newval == ZFS_CACHE_METADATA);
+
+	osi->os_primary_cache = newval;
+}
+
+static void
+secondary_cache_changed_cb(void *arg, uint64_t newval)
+{
+	objset_impl_t *osi = arg;
+
+	/*
+	 * Inheritance and range checking should have been done by now.
+	 */
+	ASSERT(newval == ZFS_CACHE_ALL || newval == ZFS_CACHE_NONE ||
+	    newval == ZFS_CACHE_METADATA);
+
+	osi->os_secondary_cache = newval;
+}
+
 void
 dmu_objset_byteswap(void *buf, size_t size)
 {
@@ -146,8 +174,10 @@ int
 dmu_objset_open_impl(spa_t *spa, dsl_dataset_t *ds, blkptr_t *bp,
     objset_impl_t **osip)
 {
-	objset_impl_t *winner, *osi;
-	int i, err, checksum;
+	objset_impl_t *osi;
+	int i, err;
+
+	ASSERT(ds == NULL || MUTEX_HELD(&ds->ds_opening_lock));
 
 	osi = kmem_zalloc(sizeof (objset_impl_t), KM_SLEEP);
 	osi->os.os = osi;
@@ -161,18 +191,26 @@ dmu_objset_open_impl(spa_t *spa, dsl_dataset_t *ds, blkptr_t *bp,
 		zb.zb_object = 0;
 		zb.zb_level = -1;
 		zb.zb_blkid = 0;
+		if (DMU_OS_IS_L2CACHEABLE(osi))
+			aflags |= ARC_L2CACHE;
 
 		dprintf_bp(osi->os_rootbp, "reading %s", "");
-		err = arc_read(NULL, spa, osi->os_rootbp,
-		    dmu_ot[DMU_OT_OBJSET].ot_byteswap,
+		/*
+		 * NB: when bprewrite scrub can change the bp,
+		 * and this is called from dmu_objset_open_ds_os, the bp
+		 * could change, and we'll need a lock.
+		 */
+		err = arc_read_nolock(NULL, spa, osi->os_rootbp,
 		    arc_getbuf_func, &osi->os_phys_buf,
 		    ZIO_PRIORITY_SYNC_READ, ZIO_FLAG_CANFAIL, &aflags, &zb);
 		if (err) {
 			kmem_free(osi, sizeof (objset_impl_t));
+			/* convert checksum errors into IO errors */
+			if (err == ECKSUM)
+				err = EIO;
 			return (err);
 		}
 		osi->os_phys = osi->os_phys_buf->b_data;
-		arc_release(osi->os_phys_buf, &osi->os_phys_buf);
 	} else {
 		osi->os_phys_buf = arc_buf_alloc(spa, sizeof (objset_phys_t),
 		    &osi->os_phys_buf, ARC_BUFC_METADATA);
@@ -183,18 +221,26 @@ dmu_objset_open_impl(spa_t *spa, dsl_dataset_t *ds, blkptr_t *bp,
 	/*
 	 * Note: the changed_cb will be called once before the register
 	 * func returns, thus changing the checksum/compression from the
-	 * default (fletcher2/off).  Snapshots don't need to know, and
-	 * registering would complicate clone promotion.
+	 * default (fletcher2/off).  Snapshots don't need to know about
+	 * checksum/compression/copies.
 	 */
-	if (ds && ds->ds_phys->ds_num_children == 0) {
-		err = dsl_prop_register(ds, "checksum",
-		    checksum_changed_cb, osi);
-		if (err == 0)
-			err = dsl_prop_register(ds, "compression",
-			    compression_changed_cb, osi);
+	if (ds) {
+		err = dsl_prop_register(ds, "primarycache",
+		    primary_cache_changed_cb, osi);
 		if (err == 0)
-			err = dsl_prop_register(ds, "copies",
-			    copies_changed_cb, osi);
+			err = dsl_prop_register(ds, "secondarycache",
+			    secondary_cache_changed_cb, osi);
+		if (!dsl_dataset_is_snapshot(ds)) {
+			if (err == 0)
+				err = dsl_prop_register(ds, "checksum",
+				    checksum_changed_cb, osi);
+			if (err == 0)
+				err = dsl_prop_register(ds, "compression",
+				    compression_changed_cb, osi);
+			if (err == 0)
+				err = dsl_prop_register(ds, "copies",
+				    copies_changed_cb, osi);
+		}
 		if (err) {
 			VERIFY(arc_buf_remove_ref(osi->os_phys_buf,
 			    &osi->os_phys_buf) == 1);
@@ -206,24 +252,12 @@ dmu_objset_open_impl(spa_t *spa, dsl_dataset_t *ds, blkptr_t *bp,
 		osi->os_checksum = ZIO_CHECKSUM_FLETCHER_4;
 		osi->os_compress = ZIO_COMPRESS_LZJB;
 		osi->os_copies = spa_max_replication(spa);
+		osi->os_primary_cache = ZFS_CACHE_ALL;
+		osi->os_secondary_cache = ZFS_CACHE_ALL;
 	}
 
-	osi->os_zil = zil_alloc(&osi->os, &osi->os_phys->os_zil_header);
-
-	/*
-	 * Metadata always gets compressed and checksummed.
-	 * If the data checksum is multi-bit correctable, and it's not
-	 * a ZBT-style checksum, then it's suitable for metadata as well.
-	 * Otherwise, the metadata checksum defaults to fletcher4.
-	 */
-	checksum = osi->os_checksum;
-
-	if (zio_checksum_table[checksum].ci_correctable &&
-	    !zio_checksum_table[checksum].ci_zbt)
-		osi->os_md_checksum = checksum;
-	else
-		osi->os_md_checksum = ZIO_CHECKSUM_FLETCHER_4;
-	osi->os_md_compress = ZIO_COMPRESS_LZJB;
+	osi->os_zil_header = osi->os_phys->os_zil_header;
+	osi->os_zil = zil_alloc(&osi->os, &osi->os_zil_header);
 
 	for (i = 0; i < TXG_SIZE; i++) {
 		list_create(&osi->os_dirty_dnodes[i], sizeof (dnode_t),
@@ -238,70 +272,118 @@ dmu_objset_open_impl(spa_t *spa, dsl_dataset_t *ds, blkptr_t *bp,
 
 	mutex_init(&osi->os_lock, NULL, MUTEX_DEFAULT, NULL);
 	mutex_init(&osi->os_obj_lock, NULL, MUTEX_DEFAULT, NULL);
+	mutex_init(&osi->os_user_ptr_lock, NULL, MUTEX_DEFAULT, NULL);
 
 	osi->os_meta_dnode = dnode_special_open(osi,
 	    &osi->os_phys->os_meta_dnode, DMU_META_DNODE_OBJECT);
 
-	if (ds != NULL) {
-		winner = dsl_dataset_set_user_ptr(ds, osi, dmu_objset_evict);
-		if (winner) {
-			dmu_objset_evict(ds, osi);
-			osi = winner;
-		}
+	/*
+	 * We should be the only thread trying to do this because we
+	 * have ds_opening_lock
+	 */
+	if (ds) {
+		VERIFY(NULL == dsl_dataset_set_user_ptr(ds, osi,
+		    dmu_objset_evict));
 	}
 
 	*osip = osi;
 	return (0);
 }
 
-/* called from zpl */
-int
-dmu_objset_open(const char *name, dmu_objset_type_t type, int mode,
-    objset_t **osp)
+static int
+dmu_objset_open_ds_os(dsl_dataset_t *ds, objset_t *os, dmu_objset_type_t type)
 {
-	dsl_dataset_t *ds;
-	int err;
-	objset_t *os;
 	objset_impl_t *osi;
 
-	os = kmem_alloc(sizeof (objset_t), KM_SLEEP);
-	err = dsl_dataset_open(name, mode, os, &ds);
-	if (err) {
-		kmem_free(os, sizeof (objset_t));
-		return (err);
-	}
-
+	mutex_enter(&ds->ds_opening_lock);
 	osi = dsl_dataset_get_user_ptr(ds);
 	if (osi == NULL) {
+		int err;
+
 		err = dmu_objset_open_impl(dsl_dataset_get_spa(ds),
 		    ds, &ds->ds_phys->ds_bp, &osi);
 		if (err) {
-			dsl_dataset_close(ds, mode, os);
-			kmem_free(os, sizeof (objset_t));
+			mutex_exit(&ds->ds_opening_lock);
 			return (err);
 		}
 	}
+	mutex_exit(&ds->ds_opening_lock);
 
 	os->os = osi;
-	os->os_mode = mode;
+	os->os_mode = DS_MODE_NOHOLD;
 
-	if (type != DMU_OST_ANY && type != os->os->os_phys->os_type) {
-		dmu_objset_close(os);
+	if (type != DMU_OST_ANY && type != os->os->os_phys->os_type)
 		return (EINVAL);
-	}
-	*osp = os;
 	return (0);
 }
 
+int
+dmu_objset_open_ds(dsl_dataset_t *ds, dmu_objset_type_t type, objset_t **osp)
+{
+	objset_t *os;
+	int err;
+
+	os = kmem_alloc(sizeof (objset_t), KM_SLEEP);
+	err = dmu_objset_open_ds_os(ds, os, type);
+	if (err)
+		kmem_free(os, sizeof (objset_t));
+	else
+		*osp = os;
+	return (err);
+}
+
+/* called from zpl */
+int
+dmu_objset_open(const char *name, dmu_objset_type_t type, int mode,
+    objset_t **osp)
+{
+	objset_t *os;
+	dsl_dataset_t *ds;
+	int err;
+
+	ASSERT(DS_MODE_TYPE(mode) == DS_MODE_USER ||
+	    DS_MODE_TYPE(mode) == DS_MODE_OWNER);
+
+	os = kmem_alloc(sizeof (objset_t), KM_SLEEP);
+	if (DS_MODE_TYPE(mode) == DS_MODE_USER)
+		err = dsl_dataset_hold(name, os, &ds);
+	else
+		err = dsl_dataset_own(name, mode, os, &ds);
+	if (err) {
+		kmem_free(os, sizeof (objset_t));
+		return (err);
+	}
+
+	err = dmu_objset_open_ds_os(ds, os, type);
+	if (err) {
+		if (DS_MODE_TYPE(mode) == DS_MODE_USER)
+			dsl_dataset_rele(ds, os);
+		else
+			dsl_dataset_disown(ds, os);
+		kmem_free(os, sizeof (objset_t));
+	} else {
+		os->os_mode = mode;
+		*osp = os;
+	}
+	return (err);
+}
+
 void
 dmu_objset_close(objset_t *os)
 {
-	dsl_dataset_close(os->os->os_dsl_dataset, os->os_mode, os);
+	ASSERT(DS_MODE_TYPE(os->os_mode) == DS_MODE_USER ||
+	    DS_MODE_TYPE(os->os_mode) == DS_MODE_OWNER ||
+	    DS_MODE_TYPE(os->os_mode) == DS_MODE_NOHOLD);
+
+	if (DS_MODE_TYPE(os->os_mode) == DS_MODE_USER)
+		dsl_dataset_rele(os->os->os_dsl_dataset, os);
+	else if (DS_MODE_TYPE(os->os_mode) == DS_MODE_OWNER)
+		dsl_dataset_disown(os->os->os_dsl_dataset, os);
 	kmem_free(os, sizeof (objset_t));
 }
 
 int
-dmu_objset_evict_dbufs(objset_t *os, int try)
+dmu_objset_evict_dbufs(objset_t *os)
 {
 	objset_impl_t *osi = os->os;
 	dnode_t *dn;
@@ -319,34 +401,25 @@ dmu_objset_evict_dbufs(objset_t *os, int try)
 	 * skip.
 	 */
 	for (dn = list_head(&osi->os_dnodes);
-	    dn && refcount_is_zero(&dn->dn_holds);
+	    dn && !dnode_add_ref(dn, FTAG);
 	    dn = list_next(&osi->os_dnodes, dn))
 		continue;
-	if (dn)
-		dnode_add_ref(dn, FTAG);
 
 	while (dn) {
 		dnode_t *next_dn = dn;
 
 		do {
 			next_dn = list_next(&osi->os_dnodes, next_dn);
-		} while (next_dn && refcount_is_zero(&next_dn->dn_holds));
-		if (next_dn)
-			dnode_add_ref(next_dn, FTAG);
+		} while (next_dn && !dnode_add_ref(next_dn, FTAG));
 
 		mutex_exit(&osi->os_lock);
-		if (dnode_evict_dbufs(dn, try)) {
-			dnode_rele(dn, FTAG);
-			if (next_dn)
-				dnode_rele(next_dn, FTAG);
-			return (1);
-		}
+		dnode_evict_dbufs(dn);
 		dnode_rele(dn, FTAG);
 		mutex_enter(&osi->os_lock);
 		dn = next_dn;
 	}
 	mutex_exit(&osi->os_lock);
-	return (0);
+	return (list_head(&osi->os_dnodes) != osi->os_meta_dnode);
 }
 
 void
@@ -361,13 +434,19 @@ dmu_objset_evict(dsl_dataset_t *ds, void *arg)
 		ASSERT(list_head(&osi->os_free_dnodes[i]) == NULL);
 	}
 
-	if (ds && ds->ds_phys->ds_num_children == 0) {
-		VERIFY(0 == dsl_prop_unregister(ds, "checksum",
-		    checksum_changed_cb, osi));
-		VERIFY(0 == dsl_prop_unregister(ds, "compression",
-		    compression_changed_cb, osi));
-		VERIFY(0 == dsl_prop_unregister(ds, "copies",
-		    copies_changed_cb, osi));
+	if (ds) {
+		if (!dsl_dataset_is_snapshot(ds)) {
+			VERIFY(0 == dsl_prop_unregister(ds, "checksum",
+			    checksum_changed_cb, osi));
+			VERIFY(0 == dsl_prop_unregister(ds, "compression",
+			    compression_changed_cb, osi));
+			VERIFY(0 == dsl_prop_unregister(ds, "copies",
+			    copies_changed_cb, osi));
+		}
+		VERIFY(0 == dsl_prop_unregister(ds, "primarycache",
+		    primary_cache_changed_cb, osi));
+		VERIFY(0 == dsl_prop_unregister(ds, "secondarycache",
+		    secondary_cache_changed_cb, osi));
 	}
 
 	/*
@@ -375,7 +454,7 @@ dmu_objset_evict(dsl_dataset_t *ds, void *arg)
 	 * nothing can be added to the list at this point.
 	 */
 	os.os = osi;
-	(void) dmu_objset_evict_dbufs(&os, 0);
+	(void) dmu_objset_evict_dbufs(&os);
 
 	ASSERT3P(list_head(&osi->os_dnodes), ==, osi->os_meta_dnode);
 	ASSERT3P(list_tail(&osi->os_dnodes), ==, osi->os_meta_dnode);
@@ -387,6 +466,7 @@ dmu_objset_evict(dsl_dataset_t *ds, void *arg)
 	VERIFY(arc_buf_remove_ref(osi->os_phys_buf, &osi->os_phys_buf) == 1);
 	mutex_destroy(&osi->os_lock);
 	mutex_destroy(&osi->os_obj_lock);
+	mutex_destroy(&osi->os_user_ptr_lock);
 	kmem_free(osi, sizeof (objset_impl_t));
 }
 
@@ -399,7 +479,11 @@ dmu_objset_create_impl(spa_t *spa, dsl_dataset_t *ds, blkptr_t *bp,
 	dnode_t *mdn;
 
 	ASSERT(dmu_tx_is_syncing(tx));
+	if (ds)
+		mutex_enter(&ds->ds_opening_lock);
 	VERIFY(0 == dmu_objset_open_impl(spa, ds, bp, &osi));
+	if (ds)
+		mutex_exit(&ds->ds_opening_lock);
 	mdn = osi->os_meta_dnode;
 
 	dnode_allocate(mdn, DMU_OT_DNODE, 1 << DNODE_BLOCK_SHIFT,
@@ -443,14 +527,15 @@ dmu_objset_create_impl(spa_t *spa, dsl_dataset_t *ds, blkptr_t *bp,
 }
 
 struct oscarg {
-	void (*userfunc)(objset_t *os, void *arg, dmu_tx_t *tx);
+	void (*userfunc)(objset_t *os, void *arg, cred_t *cr, dmu_tx_t *tx);
 	void *userarg;
 	dsl_dataset_t *clone_parent;
 	const char *lastname;
 	dmu_objset_type_t type;
+	uint64_t flags;
 };
 
-/* ARGSUSED */
+/*ARGSUSED*/
 static int
 dmu_objset_create_check(void *arg1, void *arg2, dmu_tx_t *tx)
 {
@@ -478,11 +563,12 @@ dmu_objset_create_check(void *arg1, void *arg2, dmu_tx_t *tx)
 		if (oa->clone_parent->ds_phys->ds_num_children == 0)
 			return (EINVAL);
 	}
+
 	return (0);
 }
 
 static void
-dmu_objset_create_sync(void *arg1, void *arg2, dmu_tx_t *tx)
+dmu_objset_create_sync(void *arg1, void *arg2, cred_t *cr, dmu_tx_t *tx)
 {
 	dsl_dir_t *dd = arg1;
 	struct oscarg *oa = arg2;
@@ -493,10 +579,9 @@ dmu_objset_create_sync(void *arg1, void *arg2, dmu_tx_t *tx)
 	ASSERT(dmu_tx_is_syncing(tx));
 
 	dsobj = dsl_dataset_create_sync(dd, oa->lastname,
-	    oa->clone_parent, tx);
+	    oa->clone_parent, oa->flags, cr, tx);
 
-	VERIFY(0 == dsl_dataset_open_obj(dd->dd_pool, dsobj, NULL,
-	    DS_MODE_STANDARD | DS_MODE_READONLY, FTAG, &ds));
+	VERIFY(0 == dsl_dataset_hold_obj(dd->dd_pool, dsobj, FTAG, &ds));
 	bp = dsl_dataset_get_blkptr(ds);
 	if (BP_IS_HOLE(bp)) {
 		objset_impl_t *osi;
@@ -506,15 +591,19 @@ dmu_objset_create_sync(void *arg1, void *arg2, dmu_tx_t *tx)
 		    ds, bp, oa->type, tx);
 
 		if (oa->userfunc)
-			oa->userfunc(&osi->os, oa->userarg, tx);
+			oa->userfunc(&osi->os, oa->userarg, cr, tx);
 	}
-	dsl_dataset_close(ds, DS_MODE_STANDARD | DS_MODE_READONLY, FTAG);
+
+	spa_history_internal_log(LOG_DS_CREATE, dd->dd_pool->dp_spa,
+	    tx, cr, "dataset = %llu", dsobj);
+
+	dsl_dataset_rele(ds, FTAG);
 }
 
 int
 dmu_objset_create(const char *name, dmu_objset_type_t type,
-    objset_t *clone_parent,
-    void (*func)(objset_t *os, void *arg, dmu_tx_t *tx), void *arg)
+    objset_t *clone_parent, uint64_t flags,
+    void (*func)(objset_t *os, void *arg, cred_t *cr, dmu_tx_t *tx), void *arg)
 {
 	dsl_dir_t *pdd;
 	const char *tail;
@@ -536,6 +625,8 @@ dmu_objset_create(const char *name, dmu_objset_type_t type,
 	oa.userarg = arg;
 	oa.lastname = tail;
 	oa.type = type;
+	oa.flags = flags;
+
 	if (clone_parent != NULL) {
 		/*
 		 * You can't clone to a different type.
@@ -564,33 +655,47 @@ dmu_objset_destroy(const char *name)
 	 * It would be nicer to do this in dsl_dataset_destroy_sync(),
 	 * but the replay log objset is modified in open context.
 	 */
-	error = dmu_objset_open(name, DMU_OST_ANY, DS_MODE_EXCLUSIVE, &os);
+	error = dmu_objset_open(name, DMU_OST_ANY,
+	    DS_MODE_OWNER|DS_MODE_READONLY|DS_MODE_INCONSISTENT, &os);
 	if (error == 0) {
+		dsl_dataset_t *ds = os->os->os_dsl_dataset;
 		zil_destroy(dmu_objset_zil(os), B_FALSE);
-		dmu_objset_close(os);
+
+		error = dsl_dataset_destroy(ds, os);
+		/*
+		 * dsl_dataset_destroy() closes the ds.
+		 */
+		kmem_free(os, sizeof (objset_t));
 	}
 
-	return (dsl_dataset_destroy(name));
+	return (error);
 }
 
+/*
+ * This will close the objset.
+ */
 int
-dmu_objset_rollback(const char *name)
+dmu_objset_rollback(objset_t *os)
 {
 	int err;
-	objset_t *os;
+	dsl_dataset_t *ds;
 
-	err = dmu_objset_open(name, DMU_OST_ANY,
-	    DS_MODE_EXCLUSIVE | DS_MODE_INCONSISTENT, &os);
-	if (err == 0) {
-		err = zil_suspend(dmu_objset_zil(os));
-		if (err == 0)
-			zil_resume(dmu_objset_zil(os));
-		if (err == 0) {
-			/* XXX uncache everything? */
-			err = dsl_dataset_rollback(os->os->os_dsl_dataset);
-		}
+	ds = os->os->os_dsl_dataset;
+
+	if (!dsl_dataset_tryown(ds, TRUE, os)) {
 		dmu_objset_close(os);
+		return (EBUSY);
 	}
+
+	err = dsl_dataset_rollback(ds, os->os->os_phys->os_type);
+
+	/*
+	 * NB: we close the objset manually because the rollback
+	 * actually implicitly called dmu_objset_evict(), thus freeing
+	 * the objset_impl_t.
+	 */
+	dsl_dataset_disown(ds, os);
+	kmem_free(os, sizeof (objset_t));
 	return (err);
 }
 
@@ -598,6 +703,13 @@ struct snaparg {
 	dsl_sync_task_group_t *dstg;
 	char *snapname;
 	char failed[MAXPATHLEN];
+	boolean_t checkperms;
+	list_t objsets;
+};
+
+struct osnode {
+	list_node_t node;
+	objset_t *os;
 };
 
 static int
@@ -605,20 +717,25 @@ dmu_objset_snapshot_one(char *name, void *arg)
 {
 	struct snaparg *sn = arg;
 	objset_t *os;
-	dmu_objset_stats_t stat;
 	int err;
 
 	(void) strcpy(sn->failed, name);
 
-	err = dmu_objset_open(name, DMU_OST_ANY, DS_MODE_STANDARD, &os);
+	/*
+	 * Check permissions only when requested.  This only applies when
+	 * doing a recursive snapshot.  The permission checks for the starting
+	 * dataset have already been performed in zfs_secpolicy_snapshot()
+	 */
+	if (sn->checkperms == B_TRUE &&
+	    (err = zfs_secpolicy_snapshot_perms(name, CRED())))
+		return (err);
+
+	err = dmu_objset_open(name, DMU_OST_ANY, DS_MODE_USER, &os);
 	if (err != 0)
 		return (err);
 
-	/*
-	 * If the objset is in an inconsistent state, return busy.
-	 */
-	dmu_objset_fast_stat(os, &stat);
-	if (stat.dds_inconsistent) {
+	/* If the objset is in an inconsistent state, return busy */
+	if (os->os->os_dsl_dataset->ds_phys->ds_flags & DS_FLAG_INCONSISTENT) {
 		dmu_objset_close(os);
 		return (EBUSY);
 	}
@@ -630,8 +747,13 @@ dmu_objset_snapshot_one(char *name, void *arg)
 	 */
 	err = zil_suspend(dmu_objset_zil(os));
 	if (err == 0) {
+		struct osnode *osn;
 		dsl_sync_task_create(sn->dstg, dsl_dataset_snapshot_check,
-		    dsl_dataset_snapshot_sync, os, sn->snapname, 3);
+		    dsl_dataset_snapshot_sync, os->os->os_dsl_dataset,
+		    sn->snapname, 3);
+		osn = kmem_alloc(sizeof (struct osnode), KM_SLEEP);
+		osn->os = os;
+		list_insert_tail(&sn->objsets, osn);
 	} else {
 		dmu_objset_close(os);
 	}
@@ -643,31 +765,28 @@ int
 dmu_objset_snapshot(char *fsname, char *snapname, boolean_t recursive)
 {
 	dsl_sync_task_t *dst;
+	struct osnode *osn;
 	struct snaparg sn = { 0 };
-	char *cp;
 	spa_t *spa;
 	int err;
 
 	(void) strcpy(sn.failed, fsname);
 
-	cp = strchr(fsname, '/');
-	if (cp) {
-		*cp = '\0';
-		err = spa_open(fsname, &spa, FTAG);
-		*cp = '/';
-	} else {
-		err = spa_open(fsname, &spa, FTAG);
-	}
+	err = spa_open(fsname, &spa, FTAG);
 	if (err)
 		return (err);
 
 	sn.dstg = dsl_sync_task_group_create(spa_get_dsl(spa));
 	sn.snapname = snapname;
+	list_create(&sn.objsets, sizeof (struct osnode),
+	    offsetof(struct osnode, node));
 
 	if (recursive) {
+		sn.checkperms = B_TRUE;
 		err = dmu_objset_find(fsname,
 		    dmu_objset_snapshot_one, &sn, DS_FIND_CHILDREN);
 	} else {
+		sn.checkperms = B_FALSE;
 		err = dmu_objset_snapshot_one(fsname, &sn);
 	}
 
@@ -678,13 +797,20 @@ dmu_objset_snapshot(char *fsname, char *snapname, boolean_t recursive)
 
 	for (dst = list_head(&sn.dstg->dstg_tasks); dst;
 	    dst = list_next(&sn.dstg->dstg_tasks, dst)) {
-		objset_t *os = dst->dst_arg1;
+		dsl_dataset_t *ds = dst->dst_arg1;
 		if (dst->dst_err)
-			dmu_objset_name(os, sn.failed);
-		zil_resume(dmu_objset_zil(os));
-		dmu_objset_close(os);
+			dsl_dataset_name(ds, sn.failed);
 	}
+
 out:
+	while (osn = list_head(&sn.objsets)) {
+		list_remove(&sn.objsets, osn);
+		zil_resume(dmu_objset_zil(osn->os));
+		dmu_objset_close(osn->os);
+		kmem_free(osn, sizeof (struct osnode));
+	}
+	list_destroy(&sn.objsets);
+
 	if (err)
 		(void) strcpy(fsname, sn.failed);
 	dsl_sync_task_group_destroy(sn.dstg);
@@ -717,39 +843,30 @@ dmu_objset_sync_dnodes(list_t *list, dmu_tx_t *tx)
 static void
 ready(zio_t *zio, arc_buf_t *abuf, void *arg)
 {
+	blkptr_t *bp = zio->io_bp;
+	blkptr_t *bp_orig = &zio->io_bp_orig;
 	objset_impl_t *os = arg;
-	blkptr_t *bp = os->os_rootbp;
 	dnode_phys_t *dnp = &os->os_phys->os_meta_dnode;
-	int i;
+
+	ASSERT(bp == os->os_rootbp);
+	ASSERT(BP_GET_TYPE(bp) == DMU_OT_OBJSET);
+	ASSERT(BP_GET_LEVEL(bp) == 0);
 
 	/*
 	 * Update rootbp fill count.
 	 */
 	bp->blk_fill = 1;	/* count the meta-dnode */
-	for (i = 0; i < dnp->dn_nblkptr; i++)
+	for (int i = 0; i < dnp->dn_nblkptr; i++)
 		bp->blk_fill += dnp->dn_blkptr[i].blk_fill;
-}
 
-/* ARGSUSED */
-static void
-killer(zio_t *zio, arc_buf_t *abuf, void *arg)
-{
-	objset_impl_t *os = arg;
-
-	ASSERT3U(zio->io_error, ==, 0);
-
-	BP_SET_TYPE(zio->io_bp, DMU_OT_OBJSET);
-	BP_SET_LEVEL(zio->io_bp, 0);
-
-	if (!DVA_EQUAL(BP_IDENTITY(zio->io_bp),
-	    BP_IDENTITY(&zio->io_bp_orig))) {
+	if (zio->io_flags & ZIO_FLAG_IO_REWRITE) {
+		ASSERT(DVA_EQUAL(BP_IDENTITY(bp), BP_IDENTITY(bp_orig)));
+	} else {
 		if (zio->io_bp_orig.blk_birth == os->os_synctx->tx_txg)
-			dsl_dataset_block_kill(os->os_dsl_dataset,
-			    &zio->io_bp_orig, NULL, os->os_synctx);
-		dsl_dataset_block_born(os->os_dsl_dataset, zio->io_bp,
-		    os->os_synctx);
+			(void) dsl_dataset_block_kill(os->os_dsl_dataset,
+			    &zio->io_bp_orig, zio, os->os_synctx);
+		dsl_dataset_block_born(os->os_dsl_dataset, bp, os->os_synctx);
 	}
-	arc_release(os->os_phys_buf, &os->os_phys_buf);
 }
 
 /* called from dsl */
@@ -758,10 +875,10 @@ dmu_objset_sync(objset_impl_t *os, zio_t *pio, dmu_tx_t *tx)
 {
 	int txgoff;
 	zbookmark_t zb;
+	writeprops_t wp = { 0 };
 	zio_t *zio;
 	list_t *list;
 	dbuf_dirty_record_t *dr;
-	int zio_flags;
 
 	dprintf_ds(os->os_dsl_dataset, "txg=%llu\n", tx->tx_txg);
 
@@ -783,19 +900,24 @@ dmu_objset_sync(objset_impl_t *os, zio_t *pio, dmu_tx_t *tx)
 	 */
 	zb.zb_objset = os->os_dsl_dataset ? os->os_dsl_dataset->ds_object : 0;
 	zb.zb_object = 0;
-	zb.zb_level = -1;
+	zb.zb_level = -1;	/* for block ordering; it's level 0 on disk */
 	zb.zb_blkid = 0;
-	zio_flags = ZIO_FLAG_MUSTSUCCEED;
-	if (dmu_ot[DMU_OT_OBJSET].ot_metadata || zb.zb_level != 0)
-		zio_flags |= ZIO_FLAG_METADATA;
-	if (BP_IS_OLDER(os->os_rootbp, tx->tx_txg))
-		dsl_dataset_block_kill(os->os_dsl_dataset,
+
+	wp.wp_type = DMU_OT_OBJSET;
+	wp.wp_level = 0;	/* on-disk BP level; see above */
+	wp.wp_copies = os->os_copies;
+	wp.wp_oschecksum = os->os_checksum;
+	wp.wp_oscompress = os->os_compress;
+
+	if (BP_IS_OLDER(os->os_rootbp, tx->tx_txg)) {
+		(void) dsl_dataset_block_kill(os->os_dsl_dataset,
 		    os->os_rootbp, pio, tx);
-	zio = arc_write(pio, os->os_spa, os->os_md_checksum,
-	    os->os_md_compress,
-	    dmu_get_replication_level(os, &zb, DMU_OT_OBJSET),
-	    tx->tx_txg, os->os_rootbp, os->os_phys_buf, ready, killer, os,
-	    ZIO_PRIORITY_ASYNC_WRITE, zio_flags, &zb);
+	}
+
+	arc_release(os->os_phys_buf, &os->os_phys_buf);
+	zio = arc_write(pio, os->os_spa, &wp, DMU_OS_IS_L2CACHEABLE(os),
+	    tx->tx_txg, os->os_rootbp, os->os_phys_buf, ready, NULL, os,
+	    ZIO_PRIORITY_ASYNC_WRITE, ZIO_FLAG_MUSTSUCCEED, &zb);
 
 	/*
 	 * Sync meta-dnode - the parent IO for the sync is the root block
@@ -819,6 +941,7 @@ dmu_objset_sync(objset_impl_t *os, zio_t *pio, dmu_tx_t *tx)
 	 * Free intent log blocks up to this tx.
 	 */
 	zil_sync(os->os_zil, tx);
+	os->os_phys->os_zil_header = os->os_zil_header;
 	zio_nowait(zio);
 }
 
@@ -867,8 +990,23 @@ dmu_objset_is_snapshot(objset_t *os)
 }
 
 int
+dmu_snapshot_realname(objset_t *os, char *name, char *real, int maxlen,
+    boolean_t *conflict)
+{
+	dsl_dataset_t *ds = os->os->os_dsl_dataset;
+	uint64_t ignored;
+
+	if (ds->ds_phys->ds_snapnames_zapobj == 0)
+		return (ENOENT);
+
+	return (zap_lookup_norm(ds->ds_dir->dd_pool->dp_meta_objset,
+	    ds->ds_phys->ds_snapnames_zapobj, name, 8, 1, &ignored, MT_FIRST,
+	    real, maxlen, conflict));
+}
+
+int
 dmu_snapshot_list_next(objset_t *os, int namelen, char *name,
-    uint64_t *idp, uint64_t *offp)
+    uint64_t *idp, uint64_t *offp, boolean_t *case_conflict)
 {
 	dsl_dataset_t *ds = os->os->os_dsl_dataset;
 	zap_cursor_t cursor;
@@ -894,6 +1032,8 @@ dmu_snapshot_list_next(objset_t *os, int namelen, char *name,
 	(void) strcpy(name, attr.za_name);
 	if (idp)
 		*idp = attr.za_first_integer;
+	if (case_conflict)
+		*case_conflict = attr.za_normalization_conflict;
 	zap_cursor_advance(&cursor);
 	*offp = zap_cursor_serialize(&cursor);
 	zap_cursor_fini(&cursor);
@@ -938,48 +1078,80 @@ dmu_dir_list_next(objset_t *os, int namelen, char *name,
 	return (0);
 }
 
+struct findarg {
+	int (*func)(char *, void *);
+	void *arg;
+};
+
+/* ARGSUSED */
+static int
+findfunc(spa_t *spa, uint64_t dsobj, const char *dsname, void *arg)
+{
+	struct findarg *fa = arg;
+	return (fa->func((char *)dsname, fa->arg));
+}
+
 /*
  * Find all objsets under name, and for each, call 'func(child_name, arg)'.
+ * Perhaps change all callers to use dmu_objset_find_spa()?
  */
 int
 dmu_objset_find(char *name, int func(char *, void *), void *arg, int flags)
 {
+	struct findarg fa;
+	fa.func = func;
+	fa.arg = arg;
+	return (dmu_objset_find_spa(NULL, name, findfunc, &fa, flags));
+}
+
+/*
+ * Find all objsets under name, call func on each
+ */
+int
+dmu_objset_find_spa(spa_t *spa, const char *name,
+    int func(spa_t *, uint64_t, const char *, void *), void *arg, int flags)
+{
 	dsl_dir_t *dd;
-	objset_t *os;
-	uint64_t snapobj;
+	dsl_pool_t *dp;
+	dsl_dataset_t *ds;
 	zap_cursor_t zc;
 	zap_attribute_t *attr;
 	char *child;
-	int do_self, err;
+	uint64_t thisobj;
+	int err;
 
-	err = dsl_dir_open(name, FTAG, &dd, NULL);
+	if (name == NULL)
+		name = spa_name(spa);
+	err = dsl_dir_open_spa(spa, name, FTAG, &dd, NULL);
 	if (err)
 		return (err);
 
-	/* NB: the $MOS dir doesn't have a head dataset */
-	do_self = (dd->dd_phys->dd_head_dataset_obj != 0);
+	/* Don't visit hidden ($MOS & $ORIGIN) objsets. */
+	if (dd->dd_myname[0] == '$') {
+		dsl_dir_close(dd, FTAG);
+		return (0);
+	}
+
+	thisobj = dd->dd_phys->dd_head_dataset_obj;
 	attr = kmem_alloc(sizeof (zap_attribute_t), KM_SLEEP);
+	dp = dd->dd_pool;
 
 	/*
 	 * Iterate over all children.
 	 */
 	if (flags & DS_FIND_CHILDREN) {
-		for (zap_cursor_init(&zc, dd->dd_pool->dp_meta_objset,
+		for (zap_cursor_init(&zc, dp->dp_meta_objset,
 		    dd->dd_phys->dd_child_dir_zapobj);
 		    zap_cursor_retrieve(&zc, attr) == 0;
 		    (void) zap_cursor_advance(&zc)) {
 			ASSERT(attr->za_integer_length == sizeof (uint64_t));
 			ASSERT(attr->za_num_integers == 1);
 
-			/*
-			 * No separating '/' because parent's name ends in /.
-			 */
 			child = kmem_alloc(MAXPATHLEN, KM_SLEEP);
-			/* XXX could probably just use name here */
-			dsl_dir_name(dd, child);
+			(void) strcpy(child, name);
 			(void) strcat(child, "/");
 			(void) strcat(child, attr->za_name);
-			err = dmu_objset_find(child, func, arg, flags);
+			err = dmu_objset_find_spa(spa, child, func, arg, flags);
 			kmem_free(child, MAXPATHLEN);
 			if (err)
 				break;
@@ -996,30 +1168,36 @@ dmu_objset_find(char *name, int func(char *, void *), void *arg, int flags)
 	/*
 	 * Iterate over all snapshots.
 	 */
-	if ((flags & DS_FIND_SNAPSHOTS) &&
-	    dmu_objset_open(name, DMU_OST_ANY,
-	    DS_MODE_STANDARD | DS_MODE_READONLY, &os) == 0) {
-
-		snapobj = os->os->os_dsl_dataset->ds_phys->ds_snapnames_zapobj;
-		dmu_objset_close(os);
-
-		for (zap_cursor_init(&zc, dd->dd_pool->dp_meta_objset, snapobj);
-		    zap_cursor_retrieve(&zc, attr) == 0;
-		    (void) zap_cursor_advance(&zc)) {
-			ASSERT(attr->za_integer_length == sizeof (uint64_t));
-			ASSERT(attr->za_num_integers == 1);
+	if (flags & DS_FIND_SNAPSHOTS) {
+		if (!dsl_pool_sync_context(dp))
+			rw_enter(&dp->dp_config_rwlock, RW_READER);
+		err = dsl_dataset_hold_obj(dp, thisobj, FTAG, &ds);
+		if (!dsl_pool_sync_context(dp))
+			rw_exit(&dp->dp_config_rwlock);
 
-			child = kmem_alloc(MAXPATHLEN, KM_SLEEP);
-			/* XXX could probably just use name here */
-			dsl_dir_name(dd, child);
-			(void) strcat(child, "@");
-			(void) strcat(child, attr->za_name);
-			err = func(child, arg);
-			kmem_free(child, MAXPATHLEN);
-			if (err)
-				break;
+		if (err == 0) {
+			uint64_t snapobj = ds->ds_phys->ds_snapnames_zapobj;
+			dsl_dataset_rele(ds, FTAG);
+
+			for (zap_cursor_init(&zc, dp->dp_meta_objset, snapobj);
+			    zap_cursor_retrieve(&zc, attr) == 0;
+			    (void) zap_cursor_advance(&zc)) {
+				ASSERT(attr->za_integer_length ==
+				    sizeof (uint64_t));
+				ASSERT(attr->za_num_integers == 1);
+
+				child = kmem_alloc(MAXPATHLEN, KM_SLEEP);
+				(void) strcpy(child, name);
+				(void) strcat(child, "@");
+				(void) strcat(child, attr->za_name);
+				err = func(spa, attr->za_first_integer,
+				    child, arg);
+				kmem_free(child, MAXPATHLEN);
+				if (err)
+					break;
+			}
+			zap_cursor_fini(&zc);
 		}
-		zap_cursor_fini(&zc);
 	}
 
 	dsl_dir_close(dd, FTAG);
@@ -1031,7 +1209,20 @@ dmu_objset_find(char *name, int func(char *, void *), void *arg, int flags)
 	/*
 	 * Apply to self if appropriate.
 	 */
-	if (do_self)
-		err = func(name, arg);
+	err = func(spa, thisobj, name, arg);
 	return (err);
 }
+
+void
+dmu_objset_set_user(objset_t *os, void *user_ptr)
+{
+	ASSERT(MUTEX_HELD(&os->os->os_user_ptr_lock));
+	os->os->os_user_ptr = user_ptr;
+}
+
+void *
+dmu_objset_get_user(objset_t *os)
+{
+	ASSERT(MUTEX_HELD(&os->os->os_user_ptr_lock));
+	return (os->os->os_user_ptr);
+}
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_send.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_send.c
index 3e55dc301620..1294581a7133 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_send.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_send.c
@@ -19,7 +19,7 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
@@ -41,10 +41,13 @@
 #include <sys/zap.h>
 #include <sys/zio_checksum.h>
 
+static char *dmu_recv_tag = "dmu_recv_tag";
+
 struct backuparg {
 	dmu_replay_record_t *drr;
 	kthread_t *td;
 	struct file *fp;
+	offset_t *off;
 	objset_t *os;
 	zio_cksum_t zc;
 	int err;
@@ -77,6 +80,7 @@ dump_bytes(struct backuparg *ba, void *buf, int len)
 	fprintf(stderr, "%s: returning EOPNOTSUPP\n", __func__);
 	ba->err = EOPNOTSUPP;
 #endif
+	*ba->off += len;
 
 	return (ba->err);
 }
@@ -179,7 +183,7 @@ backup_cb(traverse_blk_cache_t *bc, spa_t *spa, void *arg)
 	void *data = bc->bc_data;
 	int err = 0;
 
-	if (SIGPENDING(curthread))
+	if (issig(JUSTLOOKING) && issig(FORREAL))
 		return (EINTR);
 
 	ASSERT(data || bp == NULL);
@@ -215,10 +219,9 @@ backup_cb(traverse_blk_cache_t *bc, spa_t *spa, void *arg)
 			zb.zb_object = object;
 			zb.zb_level = level;
 			zb.zb_blkid = blkid;
-			(void) arc_read(NULL, spa, bp,
-			    dmu_ot[type].ot_byteswap, arc_getbuf_func, &abuf,
-			    ZIO_PRIORITY_ASYNC_READ, ZIO_FLAG_MUSTSUCCEED,
-			    &aflags, &zb);
+			(void) arc_read_nolock(NULL, spa, bp,
+			    arc_getbuf_func, &abuf, ZIO_PRIORITY_ASYNC_READ,
+			    ZIO_FLAG_MUSTSUCCEED, &aflags, &zb);
 
 			if (abuf) {
 				err = dump_data(ba, type, object, blkid * blksz,
@@ -236,13 +239,15 @@ backup_cb(traverse_blk_cache_t *bc, spa_t *spa, void *arg)
 }
 
 int
-dmu_sendbackup(objset_t *tosnap, objset_t *fromsnap, struct file *fp)
+dmu_sendbackup(objset_t *tosnap, objset_t *fromsnap, boolean_t fromorigin,
+    struct file *fp, offset_t *off)
 {
 	dsl_dataset_t *ds = tosnap->os->os_dsl_dataset;
 	dsl_dataset_t *fromds = fromsnap ? fromsnap->os->os_dsl_dataset : NULL;
 	dmu_replay_record_t *drr;
 	struct backuparg ba;
 	int err;
+	uint64_t fromtxg = 0;
 
 	/* tosnap must be a snapshot */
 	if (ds->ds_phys->ds_next_snap_obj == 0)
@@ -250,26 +255,55 @@ dmu_sendbackup(objset_t *tosnap, objset_t *fromsnap, struct file *fp)
 
 	/* fromsnap must be an earlier snapshot from the same fs as tosnap */
 	if (fromds && (ds->ds_dir != fromds->ds_dir ||
-	    fromds->ds_phys->ds_creation_txg >=
-	    ds->ds_phys->ds_creation_txg))
+	    fromds->ds_phys->ds_creation_txg >= ds->ds_phys->ds_creation_txg))
 		return (EXDEV);
 
+	if (fromorigin) {
+		dsl_pool_t *dp = ds->ds_dir->dd_pool;
+
+		if (fromsnap)
+			return (EINVAL);
+
+		if (dsl_dir_is_clone(ds->ds_dir)) {
+			rw_enter(&dp->dp_config_rwlock, RW_READER);
+			err = dsl_dataset_hold_obj(dp,
+			    ds->ds_dir->dd_phys->dd_origin_obj, FTAG, &fromds);
+			rw_exit(&dp->dp_config_rwlock);
+			if (err)
+				return (err);
+		} else {
+			fromorigin = B_FALSE;
+		}
+	}
+
+
 	drr = kmem_zalloc(sizeof (dmu_replay_record_t), KM_SLEEP);
 	drr->drr_type = DRR_BEGIN;
 	drr->drr_u.drr_begin.drr_magic = DMU_BACKUP_MAGIC;
-	drr->drr_u.drr_begin.drr_version = DMU_BACKUP_VERSION;
+	drr->drr_u.drr_begin.drr_version = DMU_BACKUP_STREAM_VERSION;
 	drr->drr_u.drr_begin.drr_creation_time =
 	    ds->ds_phys->ds_creation_time;
 	drr->drr_u.drr_begin.drr_type = tosnap->os->os_phys->os_type;
+	if (fromorigin)
+		drr->drr_u.drr_begin.drr_flags |= DRR_FLAG_CLONE;
 	drr->drr_u.drr_begin.drr_toguid = ds->ds_phys->ds_guid;
+	if (ds->ds_phys->ds_flags & DS_FLAG_CI_DATASET)
+		drr->drr_u.drr_begin.drr_flags |= DRR_FLAG_CI_DATA;
+
 	if (fromds)
 		drr->drr_u.drr_begin.drr_fromguid = fromds->ds_phys->ds_guid;
 	dsl_dataset_name(ds, drr->drr_u.drr_begin.drr_toname);
 
+	if (fromds)
+		fromtxg = fromds->ds_phys->ds_creation_txg;
+	if (fromorigin)
+		dsl_dataset_rele(fromds, FTAG);
+
 	ba.drr = drr;
 	ba.td = curthread;
 	ba.fp = fp;
 	ba.os = tosnap;
+	ba.off = off;
 	ZIO_SET_CHECKSUM(&ba.zc, 0, 0, 0, 0);
 
 	if (dump_bytes(&ba, drr, sizeof (dmu_replay_record_t))) {
@@ -277,8 +311,7 @@ dmu_sendbackup(objset_t *tosnap, objset_t *fromsnap, struct file *fp)
 		return (ba.err);
 	}
 
-	err = traverse_dsl_dataset(ds,
-	    fromds ? fromds->ds_phys->ds_creation_txg : 0,
+	err = traverse_dsl_dataset(ds, fromtxg,
 	    ADVANCE_PRE | ADVANCE_HOLES | ADVANCE_DATA | ADVANCE_NOLOCK,
 	    backup_cb, &ba);
 
@@ -303,164 +336,384 @@ dmu_sendbackup(objset_t *tosnap, objset_t *fromsnap, struct file *fp)
 	return (0);
 }
 
-struct restorearg {
-	int err;
-	int byteswap;
-	kthread_t *td;
-	struct file *fp;
-	char *buf;
-	uint64_t voff;
-	int buflen; /* number of valid bytes in buf */
-	int bufoff; /* next offset to read */
-	int bufsize; /* amount of memory allocated for buf */
-	zio_cksum_t zc;
+struct recvbeginsyncarg {
+	const char *tofs;
+	const char *tosnap;
+	dsl_dataset_t *origin;
+	uint64_t fromguid;
+	dmu_objset_type_t type;
+	void *tag;
+	boolean_t force;
+	uint64_t dsflags;
+	char clonelastname[MAXNAMELEN];
+	dsl_dataset_t *ds; /* the ds to recv into; returned from the syncfunc */
 };
 
+static dsl_dataset_t *
+recv_full_sync_impl(dsl_pool_t *dp, uint64_t dsobj, dmu_objset_type_t type,
+    cred_t *cr, dmu_tx_t *tx)
+{
+	dsl_dataset_t *ds;
+
+	/* This should always work, since we just created it */
+	/* XXX - create should return an owned ds */
+	VERIFY(0 == dsl_dataset_own_obj(dp, dsobj,
+	    DS_MODE_INCONSISTENT, dmu_recv_tag, &ds));
+
+	if (type != DMU_OST_NONE) {
+		(void) dmu_objset_create_impl(dp->dp_spa,
+		    ds, &ds->ds_phys->ds_bp, type, tx);
+	}
+
+	spa_history_internal_log(LOG_DS_REPLAY_FULL_SYNC,
+	    dp->dp_spa, tx, cr, "dataset = %lld", dsobj);
+
+	return (ds);
+}
+
 /* ARGSUSED */
 static int
-replay_incremental_check(void *arg1, void *arg2, dmu_tx_t *tx)
+recv_full_check(void *arg1, void *arg2, dmu_tx_t *tx)
 {
-	dsl_dataset_t *ds = arg1;
-	struct drr_begin *drrb = arg2;
-	const char *snapname;
-	int err;
+	dsl_dir_t *dd = arg1;
+	struct recvbeginsyncarg *rbsa = arg2;
+	objset_t *mos = dd->dd_pool->dp_meta_objset;
 	uint64_t val;
+	int err;
 
-	/* must already be a snapshot of this fs */
-	if (ds->ds_phys->ds_prev_snap_obj == 0)
-		return (ENODEV);
+	err = zap_lookup(mos, dd->dd_phys->dd_child_dir_zapobj,
+	    strrchr(rbsa->tofs, '/') + 1, sizeof (uint64_t), 1, &val);
 
-	/* most recent snapshot must match fromguid */
-	if (ds->ds_prev->ds_phys->ds_guid != drrb->drr_fromguid)
-		return (ENODEV);
-	/* must not have any changes since most recent snapshot */
-	if (ds->ds_phys->ds_bp.blk_birth >
-	    ds->ds_prev->ds_phys->ds_creation_txg)
-		return (ETXTBSY);
+	if (err != ENOENT)
+		return (err ? err : EEXIST);
 
-	/* new snapshot name must not exist */
-	snapname = strrchr(drrb->drr_toname, '@');
-	if (snapname == NULL)
-		return (EEXIST);
+	if (rbsa->origin) {
+		/* make sure it's a snap in the same pool */
+		if (rbsa->origin->ds_dir->dd_pool != dd->dd_pool)
+			return (EXDEV);
+		if (rbsa->origin->ds_phys->ds_num_children == 0)
+			return (EINVAL);
+		if (rbsa->origin->ds_phys->ds_guid != rbsa->fromguid)
+			return (ENODEV);
+	}
 
-	snapname++;
-	err = zap_lookup(ds->ds_dir->dd_pool->dp_meta_objset,
-	    ds->ds_phys->ds_snapnames_zapobj, snapname, 8, 1, &val);
-	if (err == 0)
-		return (EEXIST);
-	if (err != ENOENT)
+	return (0);
+}
+
+static void
+recv_full_sync(void *arg1, void *arg2, cred_t *cr, dmu_tx_t *tx)
+{
+	dsl_dir_t *dd = arg1;
+	struct recvbeginsyncarg *rbsa = arg2;
+	uint64_t flags = DS_FLAG_INCONSISTENT | rbsa->dsflags;
+	uint64_t dsobj;
+
+	dsobj = dsl_dataset_create_sync(dd, strrchr(rbsa->tofs, '/') + 1,
+	    rbsa->origin, flags, cr, tx);
+
+	rbsa->ds = recv_full_sync_impl(dd->dd_pool, dsobj,
+	    rbsa->origin ? DMU_OST_NONE : rbsa->type, cr, tx);
+}
+
+static int
+recv_full_existing_check(void *arg1, void *arg2, dmu_tx_t *tx)
+{
+	dsl_dataset_t *ds = arg1;
+	struct recvbeginsyncarg *rbsa = arg2;
+	int err;
+
+	/* must be a head ds */
+	if (ds->ds_phys->ds_next_snap_obj != 0)
+		return (EINVAL);
+
+	/* must not be a clone ds */
+	if (dsl_dir_is_clone(ds->ds_dir))
+		return (EINVAL);
+
+	err = dsl_dataset_destroy_check(ds, rbsa->tag, tx);
+	if (err)
 		return (err);
 
+	if (rbsa->origin) {
+		/* make sure it's a snap in the same pool */
+		if (rbsa->origin->ds_dir->dd_pool != ds->ds_dir->dd_pool)
+			return (EXDEV);
+		if (rbsa->origin->ds_phys->ds_num_children == 0)
+			return (EINVAL);
+		if (rbsa->origin->ds_phys->ds_guid != rbsa->fromguid)
+			return (ENODEV);
+	}
+
 	return (0);
 }
 
-/* ARGSUSED */
 static void
-replay_incremental_sync(void *arg1, void *arg2, dmu_tx_t *tx)
+recv_full_existing_sync(void *arg1, void *arg2, cred_t *cr, dmu_tx_t *tx)
 {
 	dsl_dataset_t *ds = arg1;
-	dmu_buf_will_dirty(ds->ds_dbuf, tx);
-	ds->ds_phys->ds_flags |= DS_FLAG_INCONSISTENT;
+	struct recvbeginsyncarg *rbsa = arg2;
+	dsl_dir_t *dd = ds->ds_dir;
+	uint64_t flags = DS_FLAG_INCONSISTENT | rbsa->dsflags;
+	uint64_t dsobj;
+
+	/*
+	 * NB: caller must provide an extra hold on the dsl_dir_t, so it
+	 * won't go away when dsl_dataset_destroy_sync() closes the
+	 * dataset.
+	 */
+	dsl_dataset_destroy_sync(ds, rbsa->tag, cr, tx);
+
+	dsobj = dsl_dataset_create_sync_dd(dd, rbsa->origin, flags, tx);
+
+	rbsa->ds = recv_full_sync_impl(dd->dd_pool, dsobj,
+	    rbsa->origin ? DMU_OST_NONE : rbsa->type, cr, tx);
 }
 
 /* ARGSUSED */
 static int
-replay_full_check(void *arg1, void *arg2, dmu_tx_t *tx)
+recv_incremental_check(void *arg1, void *arg2, dmu_tx_t *tx)
 {
-	dsl_dir_t *dd = arg1;
-	struct drr_begin *drrb = arg2;
-	objset_t *mos = dd->dd_pool->dp_meta_objset;
-	char *cp;
-	uint64_t val;
+	dsl_dataset_t *ds = arg1;
+	struct recvbeginsyncarg *rbsa = arg2;
 	int err;
+	uint64_t val;
 
-	cp = strchr(drrb->drr_toname, '@');
-	*cp = '\0';
-	err = zap_lookup(mos, dd->dd_phys->dd_child_dir_zapobj,
-	    strrchr(drrb->drr_toname, '/') + 1,
-	    sizeof (uint64_t), 1, &val);
-	*cp = '@';
+	/* must not have any changes since most recent snapshot */
+	if (!rbsa->force && dsl_dataset_modified_since_lastsnap(ds))
+		return (ETXTBSY);
+
+	/* must already be a snapshot of this fs */
+	if (ds->ds_phys->ds_prev_snap_obj == 0)
+		return (ENODEV);
+
+	/* most recent snapshot must match fromguid */
+	if (ds->ds_prev->ds_phys->ds_guid != rbsa->fromguid)
+		return (ENODEV);
 
+	/* temporary clone name must not exist */
+	err = zap_lookup(ds->ds_dir->dd_pool->dp_meta_objset,
+	    ds->ds_dir->dd_phys->dd_child_dir_zapobj,
+	    rbsa->clonelastname, 8, 1, &val);
+	if (err == 0)
+		return (EEXIST);
 	if (err != ENOENT)
-		return (err ? err : EEXIST);
+		return (err);
 
+	/* new snapshot name must not exist */
+	err = zap_lookup(ds->ds_dir->dd_pool->dp_meta_objset,
+	    ds->ds_phys->ds_snapnames_zapobj, rbsa->tosnap, 8, 1, &val);
+	if (err == 0)
+		return (EEXIST);
+	if (err != ENOENT)
+		return (err);
 	return (0);
 }
 
+/* ARGSUSED */
 static void
-replay_full_sync(void *arg1, void *arg2, dmu_tx_t *tx)
+recv_online_incremental_sync(void *arg1, void *arg2, cred_t *cr, dmu_tx_t *tx)
 {
-	dsl_dir_t *dd = arg1;
-	struct drr_begin *drrb = arg2;
-	char *cp;
-	dsl_dataset_t *ds;
+	dsl_dataset_t *ohds = arg1;
+	struct recvbeginsyncarg *rbsa = arg2;
+	dsl_pool_t *dp = ohds->ds_dir->dd_pool;
+	dsl_dataset_t *ods, *cds;
+	uint64_t flags = DS_FLAG_INCONSISTENT | rbsa->dsflags;
 	uint64_t dsobj;
 
-	cp = strchr(drrb->drr_toname, '@');
-	*cp = '\0';
-	dsobj = dsl_dataset_create_sync(dd, strrchr(drrb->drr_toname, '/') + 1,
-	    NULL, tx);
-	*cp = '@';
+	/* create the temporary clone */
+	VERIFY(0 == dsl_dataset_hold_obj(dp, ohds->ds_phys->ds_prev_snap_obj,
+	    FTAG, &ods));
+	dsobj = dsl_dataset_create_sync(ohds->ds_dir,
+	    rbsa->clonelastname, ods, flags, cr, tx);
+	dsl_dataset_rele(ods, FTAG);
+
+	/* open the temporary clone */
+	VERIFY(0 == dsl_dataset_own_obj(dp, dsobj,
+	    DS_MODE_INCONSISTENT, dmu_recv_tag, &cds));
 
-	VERIFY(0 == dsl_dataset_open_obj(dd->dd_pool, dsobj, NULL,
-	    DS_MODE_EXCLUSIVE, FTAG, &ds));
+	/* copy the refquota from the target fs to the clone */
+	if (ohds->ds_quota > 0)
+		dsl_dataset_set_quota_sync(cds, &ohds->ds_quota, cr, tx);
 
-	(void) dmu_objset_create_impl(dsl_dataset_get_spa(ds),
-	    ds, &ds->ds_phys->ds_bp, drrb->drr_type, tx);
+	rbsa->ds = cds;
+
+	spa_history_internal_log(LOG_DS_REPLAY_INC_SYNC,
+	    dp->dp_spa, tx, cr, "dataset = %lld", dsobj);
+}
+
+/* ARGSUSED */
+static void
+recv_offline_incremental_sync(void *arg1, void *arg2, cred_t *cr, dmu_tx_t *tx)
+{
+	dsl_dataset_t *ds = arg1;
 
 	dmu_buf_will_dirty(ds->ds_dbuf, tx);
 	ds->ds_phys->ds_flags |= DS_FLAG_INCONSISTENT;
 
-	dsl_dataset_close(ds, DS_MODE_EXCLUSIVE, FTAG);
+	spa_history_internal_log(LOG_DS_REPLAY_INC_SYNC,
+	    ds->ds_dir->dd_pool->dp_spa, tx, cr, "dataset = %lld",
+	    ds->ds_object);
 }
 
-static int
-replay_end_check(void *arg1, void *arg2, dmu_tx_t *tx)
+/*
+ * NB: callers *MUST* call dmu_recv_stream() if dmu_recv_begin()
+ * succeeds; otherwise we will leak the holds on the datasets.
+ */
+int
+dmu_recv_begin(char *tofs, char *tosnap, struct drr_begin *drrb,
+    boolean_t force, objset_t *origin, boolean_t online, dmu_recv_cookie_t *drc)
 {
-	objset_t *os = arg1;
-	struct drr_begin *drrb = arg2;
-	char *snapname;
+	int err = 0;
+	boolean_t byteswap;
+	struct recvbeginsyncarg rbsa;
+	uint64_t version;
+	int flags;
+	dsl_dataset_t *ds;
 
-	/* XXX verify that drr_toname is in dd */
+	if (drrb->drr_magic == DMU_BACKUP_MAGIC)
+		byteswap = FALSE;
+	else if (drrb->drr_magic == BSWAP_64(DMU_BACKUP_MAGIC))
+		byteswap = TRUE;
+	else
+		return (EINVAL);
 
-	snapname = strchr(drrb->drr_toname, '@');
-	if (snapname == NULL)
+	rbsa.tofs = tofs;
+	rbsa.tosnap = tosnap;
+	rbsa.origin = origin ? origin->os->os_dsl_dataset : NULL;
+	rbsa.fromguid = drrb->drr_fromguid;
+	rbsa.type = drrb->drr_type;
+	rbsa.tag = FTAG;
+	rbsa.dsflags = 0;
+	version = drrb->drr_version;
+	flags = drrb->drr_flags;
+
+	if (byteswap) {
+		rbsa.type = BSWAP_32(rbsa.type);
+		rbsa.fromguid = BSWAP_64(rbsa.fromguid);
+		version = BSWAP_64(version);
+		flags = BSWAP_32(flags);
+	}
+
+	if (version != DMU_BACKUP_STREAM_VERSION ||
+	    rbsa.type >= DMU_OST_NUMTYPES ||
+	    ((flags & DRR_FLAG_CLONE) && origin == NULL))
 		return (EINVAL);
-	snapname++;
 
-	return (dsl_dataset_snapshot_check(os, snapname, tx));
-}
+	if (flags & DRR_FLAG_CI_DATA)
+		rbsa.dsflags = DS_FLAG_CI_DATASET;
 
-static void
-replay_end_sync(void *arg1, void *arg2, dmu_tx_t *tx)
-{
-	objset_t *os = arg1;
-	struct drr_begin *drrb = arg2;
-	char *snapname;
-	dsl_dataset_t *ds, *hds;
+	bzero(drc, sizeof (dmu_recv_cookie_t));
+	drc->drc_drrb = drrb;
+	drc->drc_tosnap = tosnap;
+	drc->drc_force = force;
 
-	snapname = strchr(drrb->drr_toname, '@') + 1;
+	/*
+	 * Process the begin in syncing context.
+	 */
+	if (rbsa.fromguid && !(flags & DRR_FLAG_CLONE) && !online) {
+		/* offline incremental receive */
+		err = dsl_dataset_own(tofs, 0, dmu_recv_tag, &ds);
+		if (err)
+			return (err);
 
-	dsl_dataset_snapshot_sync(os, snapname, tx);
+		/*
+		 * Only do the rollback if the most recent snapshot
+		 * matches the incremental source
+		 */
+		if (force) {
+			if (ds->ds_prev == NULL ||
+			    ds->ds_prev->ds_phys->ds_guid !=
+			    rbsa.fromguid) {
+				dsl_dataset_disown(ds, dmu_recv_tag);
+				return (ENODEV);
+			}
+			(void) dsl_dataset_rollback(ds, DMU_OST_NONE);
+		}
+		rbsa.force = B_FALSE;
+		err = dsl_sync_task_do(ds->ds_dir->dd_pool,
+		    recv_incremental_check,
+		    recv_offline_incremental_sync, ds, &rbsa, 1);
+		if (err) {
+			dsl_dataset_disown(ds, dmu_recv_tag);
+			return (err);
+		}
+		drc->drc_logical_ds = drc->drc_real_ds = ds;
+	} else if (rbsa.fromguid && !(flags & DRR_FLAG_CLONE)) {
+		/* online incremental receive */
 
-	/* set snapshot's creation time and guid */
-	hds = os->os->os_dsl_dataset;
-	VERIFY(0 == dsl_dataset_open_obj(hds->ds_dir->dd_pool,
-	    hds->ds_phys->ds_prev_snap_obj, NULL,
-	    DS_MODE_PRIMARY | DS_MODE_READONLY | DS_MODE_INCONSISTENT,
-	    FTAG, &ds));
+		/* tmp clone name is: tofs/%tosnap" */
+		(void) snprintf(rbsa.clonelastname, sizeof (rbsa.clonelastname),
+		    "%%%s", tosnap);
 
-	dmu_buf_will_dirty(ds->ds_dbuf, tx);
-	ds->ds_phys->ds_creation_time = drrb->drr_creation_time;
-	ds->ds_phys->ds_guid = drrb->drr_toguid;
-	ds->ds_phys->ds_flags &= ~DS_FLAG_INCONSISTENT;
+		/* open the dataset we are logically receiving into */
+		err = dsl_dataset_hold(tofs, dmu_recv_tag, &ds);
+		if (err)
+			return (err);
 
-	dsl_dataset_close(ds, DS_MODE_PRIMARY, FTAG);
+		rbsa.force = force;
+		err = dsl_sync_task_do(ds->ds_dir->dd_pool,
+		    recv_incremental_check,
+		    recv_online_incremental_sync, ds, &rbsa, 5);
+		if (err) {
+			dsl_dataset_rele(ds, dmu_recv_tag);
+			return (err);
+		}
+		drc->drc_logical_ds = ds;
+		drc->drc_real_ds = rbsa.ds;
+	} else {
+		/* create new fs -- full backup or clone */
+		dsl_dir_t *dd = NULL;
+		const char *tail;
+
+		err = dsl_dir_open(tofs, FTAG, &dd, &tail);
+		if (err)
+			return (err);
+		if (tail == NULL) {
+			if (!force) {
+				dsl_dir_close(dd, FTAG);
+				return (EEXIST);
+			}
+
+			rw_enter(&dd->dd_pool->dp_config_rwlock, RW_READER);
+			err = dsl_dataset_own_obj(dd->dd_pool,
+			    dd->dd_phys->dd_head_dataset_obj,
+			    DS_MODE_INCONSISTENT, FTAG, &ds);
+			rw_exit(&dd->dd_pool->dp_config_rwlock);
+			if (err) {
+				dsl_dir_close(dd, FTAG);
+				return (err);
+			}
+
+			dsl_dataset_make_exclusive(ds, FTAG);
+			err = dsl_sync_task_do(dd->dd_pool,
+			    recv_full_existing_check,
+			    recv_full_existing_sync, ds, &rbsa, 5);
+			dsl_dataset_disown(ds, FTAG);
+		} else {
+			err = dsl_sync_task_do(dd->dd_pool, recv_full_check,
+			    recv_full_sync, dd, &rbsa, 5);
+		}
+		dsl_dir_close(dd, FTAG);
+		if (err)
+			return (err);
+		drc->drc_logical_ds = drc->drc_real_ds = rbsa.ds;
+		drc->drc_newfs = B_TRUE;
+	}
 
-	dmu_buf_will_dirty(hds->ds_dbuf, tx);
-	hds->ds_phys->ds_flags &= ~DS_FLAG_INCONSISTENT;
+	return (0);
 }
 
+struct restorearg {
+	int err;
+	int byteswap;
+	kthread_t *td;
+	struct file *fp;
+	char *buf;
+	uint64_t voff;
+	int bufsize; /* amount of memory allocated for buf */
+	zio_cksum_t cksum;
+};
+
 static int
 restore_bytes(struct restorearg *ra, void *buf, int len, off_t off, int *resid)
 {
@@ -491,37 +744,31 @@ static void *
 restore_read(struct restorearg *ra, int len)
 {
 	void *rv;
+	int done = 0;
 
 	/* some things will require 8-byte alignment, so everything must */
 	ASSERT3U(len % 8, ==, 0);
 
-	while (ra->buflen - ra->bufoff < len) {
+	while (done < len) {
 		int resid;
-		int leftover = ra->buflen - ra->bufoff;
 
-		(void) memmove(ra->buf, ra->buf + ra->bufoff, leftover);
+		ra->err = restore_bytes(ra, (caddr_t)ra->buf + done,
+		    len - done, ra->voff, &resid);
 
-		ra->err = restore_bytes(ra, (caddr_t)ra->buf + leftover,
-		    ra->bufsize - leftover, ra->voff, &resid);
-
-		ra->voff += ra->bufsize - leftover - resid;
-		ra->buflen = ra->bufsize - resid;
-		ra->bufoff = 0;
-		if (resid == ra->bufsize - leftover)
+		if (resid == len - done)
 			ra->err = EINVAL;
+		ra->voff += len - done - resid;
+		done = len - resid;
 		if (ra->err)
 			return (NULL);
-		/* Could compute checksum here? */
 	}
 
-	ASSERT3U(ra->bufoff % 8, ==, 0);
-	ASSERT3U(ra->buflen - ra->bufoff, >=, len);
-	rv = ra->buf + ra->bufoff;
-	ra->bufoff += len;
+	ASSERT3U(done, ==, len);
+	rv = ra->buf;
 	if (ra->byteswap)
-		fletcher_4_incremental_byteswap(rv, len, &ra->zc);
+		fletcher_4_incremental_byteswap(rv, len, &ra->cksum);
 	else
-		fletcher_4_incremental_native(rv, len, &ra->zc);
+		fletcher_4_incremental_native(rv, len, &ra->cksum);
 	return (rv);
 }
 
@@ -531,12 +778,14 @@ backup_byteswap(dmu_replay_record_t *drr)
 #define	DO64(X) (drr->drr_u.X = BSWAP_64(drr->drr_u.X))
 #define	DO32(X) (drr->drr_u.X = BSWAP_32(drr->drr_u.X))
 	drr->drr_type = BSWAP_32(drr->drr_type);
+	drr->drr_payloadlen = BSWAP_32(drr->drr_payloadlen);
 	switch (drr->drr_type) {
 	case DRR_BEGIN:
 		DO64(drr_begin.drr_magic);
 		DO64(drr_begin.drr_version);
 		DO64(drr_begin.drr_creation_time);
 		DO32(drr_begin.drr_type);
+		DO32(drr_begin.drr_flags);
 		DO64(drr_begin.drr_toguid);
 		DO64(drr_begin.drr_fromguid);
 		break;
@@ -643,13 +892,13 @@ restore_object(struct restorearg *ra, objset_t *os, struct drr_object *drro)
 		VERIFY(0 == dmu_bonus_hold(os, drro->drr_object, FTAG, &db));
 		dmu_buf_will_dirty(db, tx);
 
-		ASSERT3U(db->db_size, ==, drro->drr_bonuslen);
-		data = restore_read(ra, P2ROUNDUP(db->db_size, 8));
+		ASSERT3U(db->db_size, >=, drro->drr_bonuslen);
+		data = restore_read(ra, P2ROUNDUP(drro->drr_bonuslen, 8));
 		if (data == NULL) {
 			dmu_tx_commit(tx);
 			return (ra->err);
 		}
-		bcopy(data, db->db_data, db->db_size);
+		bcopy(data, db->db_data, drro->drr_bonuslen);
 		if (ra->byteswap) {
 			dmu_ot[drro->drr_bonustype].ot_byteswap(db->db_data,
 			    drro->drr_bonuslen);
@@ -673,23 +922,14 @@ restore_freeobjects(struct restorearg *ra, objset_t *os,
 	for (obj = drrfo->drr_firstobj;
 	    obj < drrfo->drr_firstobj + drrfo->drr_numobjs;
 	    (void) dmu_object_next(os, &obj, FALSE, 0)) {
-		dmu_tx_t *tx;
 		int err;
 
 		if (dmu_object_info(os, obj, NULL) != 0)
 			continue;
 
-		tx = dmu_tx_create(os);
-		dmu_tx_hold_bonus(tx, obj);
-		err = dmu_tx_assign(tx, TXG_WAIT);
-		if (err) {
-			dmu_tx_abort(tx);
+		err = dmu_free_object(os, obj);
+		if (err)
 			return (err);
-		}
-		err = dmu_object_free(os, obj, tx);
-		dmu_tx_commit(tx);
-		if (err && err != ENOENT)
-			return (EINVAL);
 	}
 	return (0);
 }
@@ -735,7 +975,6 @@ static int
 restore_free(struct restorearg *ra, objset_t *os,
     struct drr_free *drrf)
 {
-	dmu_tx_t *tx;
 	int err;
 
 	if (drrf->drr_length != -1ULL &&
@@ -745,66 +984,65 @@ restore_free(struct restorearg *ra, objset_t *os,
 	if (dmu_object_info(os, drrf->drr_object, NULL) != 0)
 		return (EINVAL);
 
-	tx = dmu_tx_create(os);
-
-	dmu_tx_hold_free(tx, drrf->drr_object,
+	err = dmu_free_long_range(os, drrf->drr_object,
 	    drrf->drr_offset, drrf->drr_length);
-	err = dmu_tx_assign(tx, TXG_WAIT);
-	if (err) {
-		dmu_tx_abort(tx);
-		return (err);
-	}
-	err = dmu_free_range(os, drrf->drr_object,
-	    drrf->drr_offset, drrf->drr_length, tx);
-	dmu_tx_commit(tx);
 	return (err);
 }
 
+void
+dmu_recv_abort_cleanup(dmu_recv_cookie_t *drc)
+{
+	if (drc->drc_newfs || drc->drc_real_ds != drc->drc_logical_ds) {
+		/*
+		 * online incremental or new fs: destroy the fs (which
+		 * may be a clone) that we created
+		 */
+		(void) dsl_dataset_destroy(drc->drc_real_ds, dmu_recv_tag);
+		if (drc->drc_real_ds != drc->drc_logical_ds)
+			dsl_dataset_rele(drc->drc_logical_ds, dmu_recv_tag);
+	} else {
+		/*
+		 * offline incremental: rollback to most recent snapshot.
+		 */
+		(void) dsl_dataset_rollback(drc->drc_real_ds, DMU_OST_NONE);
+		dsl_dataset_disown(drc->drc_real_ds, dmu_recv_tag);
+	}
+}
+
+/*
+ * NB: callers *must* call dmu_recv_end() if this succeeds.
+ */
 int
-dmu_recvbackup(char *tosnap, struct drr_begin *drrb, uint64_t *sizep,
-    boolean_t force, struct file *fp, uint64_t voffset)
+dmu_recv_stream(dmu_recv_cookie_t *drc, struct file *fp, offset_t *voffp)
 {
 	kthread_t *td = curthread;
-	struct restorearg ra;
+	struct restorearg ra = { 0 };
 	dmu_replay_record_t *drr;
-	char *cp;
-	objset_t *os = NULL;
-	zio_cksum_t pzc;
-
-	bzero(&ra, sizeof (ra));
-	ra.td = td;
-	ra.fp = fp;
-	ra.voff = voffset;
-	ra.bufsize = 1<<20;
-	ra.buf = kmem_alloc(ra.bufsize, KM_SLEEP);
+	objset_t *os;
+	zio_cksum_t pcksum;
 
-	if (drrb->drr_magic == DMU_BACKUP_MAGIC) {
-		ra.byteswap = FALSE;
-	} else if (drrb->drr_magic == BSWAP_64(DMU_BACKUP_MAGIC)) {
+	if (drc->drc_drrb->drr_magic == BSWAP_64(DMU_BACKUP_MAGIC))
 		ra.byteswap = TRUE;
-	} else {
-		ra.err = EINVAL;
-		goto out;
-	}
 
-	/*
-	 * NB: this assumes that struct drr_begin will be the largest in
-	 * dmu_replay_record_t's drr_u, and thus we don't need to pad it
-	 * with zeros to make it the same length as we wrote out.
-	 */
-	((dmu_replay_record_t *)ra.buf)->drr_type = DRR_BEGIN;
-	((dmu_replay_record_t *)ra.buf)->drr_pad = 0;
-	((dmu_replay_record_t *)ra.buf)->drr_u.drr_begin = *drrb;
-	if (ra.byteswap) {
-		fletcher_4_incremental_byteswap(ra.buf,
-		    sizeof (dmu_replay_record_t), &ra.zc);
-	} else {
-		fletcher_4_incremental_native(ra.buf,
-		    sizeof (dmu_replay_record_t), &ra.zc);
+	{
+		/* compute checksum of drr_begin record */
+		dmu_replay_record_t *drr;
+		drr = kmem_zalloc(sizeof (dmu_replay_record_t), KM_SLEEP);
+
+		drr->drr_type = DRR_BEGIN;
+		drr->drr_u.drr_begin = *drc->drc_drrb;
+		if (ra.byteswap) {
+			fletcher_4_incremental_byteswap(drr,
+			    sizeof (dmu_replay_record_t), &ra.cksum);
+		} else {
+			fletcher_4_incremental_native(drr,
+			    sizeof (dmu_replay_record_t), &ra.cksum);
+		}
+		kmem_free(drr, sizeof (dmu_replay_record_t));
 	}
-	(void) strcpy(drrb->drr_toname, tosnap); /* for the sync funcs */
 
 	if (ra.byteswap) {
+		struct drr_begin *drrb = drc->drc_drrb;
 		drrb->drr_magic = BSWAP_64(drrb->drr_magic);
 		drrb->drr_version = BSWAP_64(drrb->drr_version);
 		drrb->drr_creation_time = BSWAP_64(drrb->drr_creation_time);
@@ -813,94 +1051,30 @@ dmu_recvbackup(char *tosnap, struct drr_begin *drrb, uint64_t *sizep,
 		drrb->drr_fromguid = BSWAP_64(drrb->drr_fromguid);
 	}
 
-	ASSERT3U(drrb->drr_magic, ==, DMU_BACKUP_MAGIC);
-
-	if (drrb->drr_version != DMU_BACKUP_VERSION ||
-	    drrb->drr_type >= DMU_OST_NUMTYPES ||
-	    strchr(drrb->drr_toname, '@') == NULL) {
-		ra.err = EINVAL;
-		goto out;
-	}
-
-	/*
-	 * Process the begin in syncing context.
-	 */
-	if (drrb->drr_fromguid) {
-		/* incremental backup */
-		dsl_dataset_t *ds = NULL;
-
-		cp = strchr(tosnap, '@');
-		*cp = '\0';
-		ra.err = dsl_dataset_open(tosnap, DS_MODE_EXCLUSIVE, FTAG, &ds);
-		*cp = '@';
-		if (ra.err)
-			goto out;
-
-		/*
-		 * Only do the rollback if the most recent snapshot
-		 * matches the incremental source
-		 */
-		if (force) {
-			if (ds->ds_prev == NULL ||
-			    ds->ds_prev->ds_phys->ds_guid !=
-			    drrb->drr_fromguid) {
-				dsl_dataset_close(ds, DS_MODE_EXCLUSIVE, FTAG);
-				kmem_free(ra.buf, ra.bufsize);
-				return (ENODEV);
-			}
-			(void) dsl_dataset_rollback(ds);
-		}
-		ra.err = dsl_sync_task_do(ds->ds_dir->dd_pool,
-		    replay_incremental_check, replay_incremental_sync,
-		    ds, drrb, 1);
-		dsl_dataset_close(ds, DS_MODE_EXCLUSIVE, FTAG);
-	} else {
-		/* full backup */
-		dsl_dir_t *dd = NULL;
-		const char *tail;
-
-		/* can't restore full backup into topmost fs, for now */
-		if (strrchr(drrb->drr_toname, '/') == NULL) {
-			ra.err = EINVAL;
-			goto out;
-		}
-
-		cp = strchr(tosnap, '@');
-		*cp = '\0';
-		ra.err = dsl_dir_open(tosnap, FTAG, &dd, &tail);
-		*cp = '@';
-		if (ra.err)
-			goto out;
-		if (tail == NULL) {
-			ra.err = EEXIST;
-			goto out;
-		}
+	ra.td = td;
+	ra.fp = fp;
+	ra.voff = *voffp;
+	ra.bufsize = 1<<20;
+	ra.buf = kmem_alloc(ra.bufsize, KM_SLEEP);
 
-		ra.err = dsl_sync_task_do(dd->dd_pool, replay_full_check,
-		    replay_full_sync, dd, drrb, 5);
-		dsl_dir_close(dd, FTAG);
-	}
-	if (ra.err)
-		goto out;
+	/* these were verified in dmu_recv_begin */
+	ASSERT(drc->drc_drrb->drr_version == DMU_BACKUP_STREAM_VERSION);
+	ASSERT(drc->drc_drrb->drr_type < DMU_OST_NUMTYPES);
 
 	/*
 	 * Open the objset we are modifying.
 	 */
+	VERIFY(dmu_objset_open_ds(drc->drc_real_ds, DMU_OST_ANY, &os) == 0);
 
-	cp = strchr(tosnap, '@');
-	*cp = '\0';
-	ra.err = dmu_objset_open(tosnap, DMU_OST_ANY,
-	    DS_MODE_PRIMARY | DS_MODE_INCONSISTENT, &os);
-	*cp = '@';
-	ASSERT3U(ra.err, ==, 0);
+	ASSERT(drc->drc_real_ds->ds_phys->ds_flags & DS_FLAG_INCONSISTENT);
 
 	/*
 	 * Read records and process them.
 	 */
-	pzc = ra.zc;
+	pcksum = ra.cksum;
 	while (ra.err == 0 &&
 	    NULL != (drr = restore_read(&ra, sizeof (*drr)))) {
-		if (SIGPENDING(td)) {
+		if (issig(JUSTLOOKING) && issig(FORREAL)) {
 			ra.err = EINTR;
 			goto out;
 		}
@@ -947,63 +1121,116 @@ dmu_recvbackup(char *tosnap, struct drr_begin *drrb, uint64_t *sizep,
 			 * value, because the stored checksum is of
 			 * everything before the DRR_END record.
 			 */
-			if (drre.drr_checksum.zc_word[0] != 0 &&
-			    !ZIO_CHECKSUM_EQUAL(drre.drr_checksum, pzc)) {
+			if (!ZIO_CHECKSUM_EQUAL(drre.drr_checksum, pcksum))
 				ra.err = ECKSUM;
-				goto out;
-			}
-
-			ra.err = dsl_sync_task_do(dmu_objset_ds(os)->
-			    ds_dir->dd_pool, replay_end_check, replay_end_sync,
-			    os, drrb, 3);
 			goto out;
 		}
 		default:
 			ra.err = EINVAL;
 			goto out;
 		}
-		pzc = ra.zc;
+		pcksum = ra.cksum;
 	}
+	ASSERT(ra.err != 0);
 
 out:
-	if (os)
-		dmu_objset_close(os);
+	dmu_objset_close(os);
 
-	/*
-	 * Make sure we don't rollback/destroy unless we actually
-	 * processed the begin properly.  'os' will only be set if this
-	 * is the case.
-	 */
-	if (ra.err && os && tosnap && strchr(tosnap, '@')) {
+	if (ra.err != 0) {
 		/*
 		 * rollback or destroy what we created, so we don't
 		 * leave it in the restoring state.
 		 */
-		dsl_dataset_t *ds;
-		int err;
-
-		cp = strchr(tosnap, '@');
-		*cp = '\0';
-		err = dsl_dataset_open(tosnap,
-		    DS_MODE_EXCLUSIVE | DS_MODE_INCONSISTENT,
-		    FTAG, &ds);
-		if (err == 0) {
-			txg_wait_synced(ds->ds_dir->dd_pool, 0);
-			if (drrb->drr_fromguid) {
-				/* incremental: rollback to most recent snap */
-				(void) dsl_dataset_rollback(ds);
-				dsl_dataset_close(ds, DS_MODE_EXCLUSIVE, FTAG);
-			} else {
-				/* full: destroy whole fs */
-				dsl_dataset_close(ds, DS_MODE_EXCLUSIVE, FTAG);
-				(void) dsl_dataset_destroy(tosnap);
-			}
-		}
-		*cp = '@';
+		txg_wait_synced(drc->drc_real_ds->ds_dir->dd_pool, 0);
+		dmu_recv_abort_cleanup(drc);
 	}
 
 	kmem_free(ra.buf, ra.bufsize);
-	if (sizep)
-		*sizep = ra.voff;
+	*voffp = ra.voff;
 	return (ra.err);
 }
+
+struct recvendsyncarg {
+	char *tosnap;
+	uint64_t creation_time;
+	uint64_t toguid;
+};
+
+static int
+recv_end_check(void *arg1, void *arg2, dmu_tx_t *tx)
+{
+	dsl_dataset_t *ds = arg1;
+	struct recvendsyncarg *resa = arg2;
+
+	return (dsl_dataset_snapshot_check(ds, resa->tosnap, tx));
+}
+
+static void
+recv_end_sync(void *arg1, void *arg2, cred_t *cr, dmu_tx_t *tx)
+{
+	dsl_dataset_t *ds = arg1;
+	struct recvendsyncarg *resa = arg2;
+
+	dsl_dataset_snapshot_sync(ds, resa->tosnap, cr, tx);
+
+	/* set snapshot's creation time and guid */
+	dmu_buf_will_dirty(ds->ds_prev->ds_dbuf, tx);
+	ds->ds_prev->ds_phys->ds_creation_time = resa->creation_time;
+	ds->ds_prev->ds_phys->ds_guid = resa->toguid;
+	ds->ds_prev->ds_phys->ds_flags &= ~DS_FLAG_INCONSISTENT;
+
+	dmu_buf_will_dirty(ds->ds_dbuf, tx);
+	ds->ds_phys->ds_flags &= ~DS_FLAG_INCONSISTENT;
+}
+
+int
+dmu_recv_end(dmu_recv_cookie_t *drc)
+{
+	struct recvendsyncarg resa;
+	dsl_dataset_t *ds = drc->drc_logical_ds;
+	int err;
+
+	/*
+	 * XXX hack; seems the ds is still dirty and
+	 * dsl_pool_zil_clean() expects it to have a ds_user_ptr
+	 * (and zil), but clone_swap() can close it.
+	 */
+	txg_wait_synced(ds->ds_dir->dd_pool, 0);
+
+	if (ds != drc->drc_real_ds) {
+		/* we are doing an online recv */
+		if (dsl_dataset_tryown(ds, FALSE, dmu_recv_tag)) {
+			err = dsl_dataset_clone_swap(drc->drc_real_ds, ds,
+			    drc->drc_force);
+			if (err)
+				dsl_dataset_disown(ds, dmu_recv_tag);
+		} else {
+			err = EBUSY;
+			dsl_dataset_rele(ds, dmu_recv_tag);
+		}
+		/* dsl_dataset_destroy() will disown the ds */
+		(void) dsl_dataset_destroy(drc->drc_real_ds, dmu_recv_tag);
+		if (err)
+			return (err);
+	}
+
+	resa.creation_time = drc->drc_drrb->drr_creation_time;
+	resa.toguid = drc->drc_drrb->drr_toguid;
+	resa.tosnap = drc->drc_tosnap;
+
+	err = dsl_sync_task_do(ds->ds_dir->dd_pool,
+	    recv_end_check, recv_end_sync, ds, &resa, 3);
+	if (err) {
+		if (drc->drc_newfs) {
+			ASSERT(ds == drc->drc_real_ds);
+			(void) dsl_dataset_destroy(ds, dmu_recv_tag);
+			return (err);
+		} else {
+			(void) dsl_dataset_rollback(ds, DMU_OST_NONE);
+		}
+	}
+
+	/* release the hold from dmu_recv_begin */
+	dsl_dataset_disown(ds, dmu_recv_tag);
+	return (err);
+}
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_traverse.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_traverse.c
index 3d2bc3e47678..43bf82e7a682 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_traverse.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_traverse.c
@@ -19,7 +19,7 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
@@ -35,6 +35,7 @@
 #include <sys/spa.h>
 #include <sys/zio.h>
 #include <sys/dmu_impl.h>
+#include <sys/zvol.h>
 
 #define	BP_SPAN_SHIFT(level, width)	((level) * (width))
 
@@ -261,6 +262,16 @@ advance_block(zseg_t *zseg, dnode_phys_t *dnp, int rc, int advance)
 	return (EAGAIN);
 }
 
+/*
+ * The traverse_callback function will call the function specified in th_func.
+ * In the event of an error the callee, specified by th_func, must return
+ * one of the following errors:
+ *
+ *	EINTR		- Indicates that the callee wants the traversal to
+ *			  abort immediately.
+ * 	ERESTART	- The callee has acknowledged the error and would
+ *			  like to continue.
+ */
 static int
 traverse_callback(traverse_handle_t *th, zseg_t *zseg, traverse_blk_cache_t *bc)
 {
@@ -603,7 +614,10 @@ traverse_segment(traverse_handle_t *th, zseg_t *zseg, blkptr_t *mosbp)
 			th->th_locked = 0;
 		}
 
-		rc = traverse_read(th, bc, &dsp->ds_bp, dn);
+		if (BP_IS_HOLE(&dsp->ds_bp))
+			rc = ERESTART;
+		else
+			rc = traverse_read(th, bc, &dsp->ds_bp, dn);
 
 		if (rc != 0) {
 			if (rc == ERESTART)
@@ -722,6 +736,24 @@ traverse_dsl_dataset(dsl_dataset_t *ds, uint64_t txg_start, int advance,
 }
 
 int
+traverse_zvol(objset_t *os, int advance,  blkptr_cb_t func, void *arg)
+{
+	spa_t *spa = dmu_objset_spa(os);
+	traverse_handle_t *th;
+	int err;
+
+	th = traverse_init(spa, func, arg, advance, ZIO_FLAG_CANFAIL);
+
+	traverse_add_dnode(th, 0, -1ULL, dmu_objset_id(os), ZVOL_OBJ);
+
+	while ((err = traverse_more(th)) == EAGAIN)
+		continue;
+
+	traverse_fini(th);
+	return (err);
+}
+
+int
 traverse_more(traverse_handle_t *th)
 {
 	zseg_t *zseg = list_head(&th->th_seglist);
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_tx.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_tx.c
index 13fd8d4d9dce..000c3ce64eb5 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_tx.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_tx.c
@@ -19,12 +19,10 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
-#pragma ident	"%Z%%M%	%I%	%E% SMI"
-
 #include <sys/dmu.h>
 #include <sys/dmu_impl.h>
 #include <sys/dbuf.h>
@@ -157,7 +155,7 @@ dmu_tx_check_ioerr(zio_t *zio, dnode_t *dn, int level, uint64_t blkid)
 	rw_exit(&dn->dn_struct_rwlock);
 	if (db == NULL)
 		return (EIO);
-	err = dbuf_read(db, zio, DB_RF_CANFAIL);
+	err = dbuf_read(db, zio, DB_RF_CANFAIL | DB_RF_NOPREFETCH);
 	dbuf_rele(db, FTAG);
 	return (err);
 }
@@ -294,6 +292,8 @@ dmu_tx_count_dnode(dmu_tx_hold_t *txh)
 		txh->txh_space_tooverwrite += space;
 	} else {
 		txh->txh_space_towrite += space;
+		if (dn && dn->dn_dbuf->db_blkptr)
+			txh->txh_space_tounref += space;
 	}
 }
 
@@ -318,39 +318,25 @@ dmu_tx_hold_write(dmu_tx_t *tx, uint64_t object, uint64_t off, int len)
 static void
 dmu_tx_count_free(dmu_tx_hold_t *txh, uint64_t off, uint64_t len)
 {
-	uint64_t blkid, nblks;
-	uint64_t space = 0;
+	uint64_t blkid, nblks, lastblk;
+	uint64_t space = 0, unref = 0, skipped = 0;
 	dnode_t *dn = txh->txh_dnode;
 	dsl_dataset_t *ds = dn->dn_objset->os_dsl_dataset;
 	spa_t *spa = txh->txh_tx->tx_pool->dp_spa;
-	int dirty;
+	int epbs;
 
-	/*
-	 * We don't need to use any locking to check for dirtyness
-	 * because it's OK if we get stale data -- the dnode may become
-	 * dirty immediately after our check anyway.  This is just a
-	 * means to avoid the expensive count when we aren't sure we
-	 * need it.  We need to be able to deal with a dirty dnode.
-	 */
-	dirty = list_link_active(&dn->dn_dirty_link[0]) |
-	    list_link_active(&dn->dn_dirty_link[1]) |
-	    list_link_active(&dn->dn_dirty_link[2]) |
-	    list_link_active(&dn->dn_dirty_link[3]);
-	if (dirty || dn->dn_assigned_txg || dn->dn_phys->dn_nlevels == 0)
+	if (dn->dn_nlevels == 0)
 		return;
 
 	/*
-	 * the struct_rwlock protects us against dn_phys->dn_nlevels
+	 * The struct_rwlock protects us against dn_nlevels
 	 * changing, in case (against all odds) we manage to dirty &
 	 * sync out the changes after we check for being dirty.
-	 * also, dbuf_hold_impl() wants us to have the struct_rwlock.
-	 *
-	 * It's fine to use dn_datablkshift rather than the dn_phys
-	 * equivalent because if it is changing, maxblkid==0 and we will
-	 * bail.
+	 * Also, dbuf_hold_level() wants us to have the struct_rwlock.
 	 */
 	rw_enter(&dn->dn_struct_rwlock, RW_READER);
-	if (dn->dn_phys->dn_maxblkid == 0) {
+	epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT;
+	if (dn->dn_maxblkid == 0) {
 		if (off == 0 && len >= dn->dn_datablksz) {
 			blkid = 0;
 			nblks = 1;
@@ -360,78 +346,120 @@ dmu_tx_count_free(dmu_tx_hold_t *txh, uint64_t off, uint64_t len)
 		}
 	} else {
 		blkid = off >> dn->dn_datablkshift;
-		nblks = (off + len) >> dn->dn_datablkshift;
+		nblks = (len + dn->dn_datablksz - 1) >> dn->dn_datablkshift;
 
-		if (blkid >= dn->dn_phys->dn_maxblkid) {
+		if (blkid >= dn->dn_maxblkid) {
 			rw_exit(&dn->dn_struct_rwlock);
 			return;
 		}
-		if (blkid + nblks > dn->dn_phys->dn_maxblkid)
-			nblks = dn->dn_phys->dn_maxblkid - blkid;
+		if (blkid + nblks > dn->dn_maxblkid)
+			nblks = dn->dn_maxblkid - blkid;
 
-		/* don't bother after 128,000 blocks */
-		nblks = MIN(nblks, 128*1024);
 	}
-
-	if (dn->dn_phys->dn_nlevels == 1) {
+	if (dn->dn_nlevels == 1) {
 		int i;
 		for (i = 0; i < nblks; i++) {
 			blkptr_t *bp = dn->dn_phys->dn_blkptr;
-			ASSERT3U(blkid + i, <, dn->dn_phys->dn_nblkptr);
+			ASSERT3U(blkid + i, <, dn->dn_nblkptr);
 			bp += blkid + i;
 			if (dsl_dataset_block_freeable(ds, bp->blk_birth)) {
 				dprintf_bp(bp, "can free old%s", "");
 				space += bp_get_dasize(spa, bp);
 			}
+			unref += BP_GET_ASIZE(bp);
 		}
 		nblks = 0;
 	}
 
+	/*
+	 * Add in memory requirements of higher-level indirects.
+	 * This assumes a worst-possible scenario for dn_nlevels.
+	 */
+	{
+		uint64_t blkcnt = 1 + ((nblks >> epbs) >> epbs);
+		int level = (dn->dn_nlevels > 1) ? 2 : 1;
+
+		while (level++ < DN_MAX_LEVELS) {
+			txh->txh_memory_tohold += blkcnt << dn->dn_indblkshift;
+			blkcnt = 1 + (blkcnt >> epbs);
+		}
+		ASSERT(blkcnt <= dn->dn_nblkptr);
+	}
+
+	lastblk = blkid + nblks - 1;
 	while (nblks) {
 		dmu_buf_impl_t *dbuf;
-		int err, epbs, blkoff, tochk;
-
-		epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT;
-		blkoff = P2PHASE(blkid, 1<<epbs);
-		tochk = MIN((1<<epbs) - blkoff, nblks);
-
-		err = dbuf_hold_impl(dn, 1, blkid >> epbs, TRUE, FTAG, &dbuf);
-		if (err == 0) {
-			int i;
-			blkptr_t *bp;
-
-			err = dbuf_read(dbuf, NULL,
-			    DB_RF_HAVESTRUCT | DB_RF_CANFAIL);
-			if (err != 0) {
-				txh->txh_tx->tx_err = err;
-				dbuf_rele(dbuf, FTAG);
-				break;
-			}
+		uint64_t ibyte, new_blkid;
+		int epb = 1 << epbs;
+		int err, i, blkoff, tochk;
+		blkptr_t *bp;
+
+		ibyte = blkid << dn->dn_datablkshift;
+		err = dnode_next_offset(dn,
+		    DNODE_FIND_HAVELOCK, &ibyte, 2, 1, 0);
+		new_blkid = ibyte >> dn->dn_datablkshift;
+		if (err == ESRCH) {
+			skipped += (lastblk >> epbs) - (blkid >> epbs) + 1;
+			break;
+		}
+		if (err) {
+			txh->txh_tx->tx_err = err;
+			break;
+		}
+		if (new_blkid > lastblk) {
+			skipped += (lastblk >> epbs) - (blkid >> epbs) + 1;
+			break;
+		}
 
-			bp = dbuf->db.db_data;
-			bp += blkoff;
+		if (new_blkid > blkid) {
+			ASSERT((new_blkid >> epbs) > (blkid >> epbs));
+			skipped += (new_blkid >> epbs) - (blkid >> epbs) - 1;
+			nblks -= new_blkid - blkid;
+			blkid = new_blkid;
+		}
+		blkoff = P2PHASE(blkid, epb);
+		tochk = MIN(epb - blkoff, nblks);
 
-			for (i = 0; i < tochk; i++) {
-				if (dsl_dataset_block_freeable(ds,
-				    bp[i].blk_birth)) {
-					dprintf_bp(&bp[i],
-					    "can free old%s", "");
-					space += bp_get_dasize(spa, &bp[i]);
-				}
-			}
+		dbuf = dbuf_hold_level(dn, 1, blkid >> epbs, FTAG);
+
+		txh->txh_memory_tohold += dbuf->db.db_size;
+		if (txh->txh_memory_tohold > DMU_MAX_ACCESS) {
+			txh->txh_tx->tx_err = E2BIG;
 			dbuf_rele(dbuf, FTAG);
+			break;
 		}
-		if (err && err != ENOENT) {
+		err = dbuf_read(dbuf, NULL, DB_RF_HAVESTRUCT | DB_RF_CANFAIL);
+		if (err != 0) {
 			txh->txh_tx->tx_err = err;
+			dbuf_rele(dbuf, FTAG);
 			break;
 		}
 
+		bp = dbuf->db.db_data;
+		bp += blkoff;
+
+		for (i = 0; i < tochk; i++) {
+			if (dsl_dataset_block_freeable(ds, bp[i].blk_birth)) {
+				dprintf_bp(&bp[i], "can free old%s", "");
+				space += bp_get_dasize(spa, &bp[i]);
+			}
+			unref += BP_GET_ASIZE(bp);
+		}
+		dbuf_rele(dbuf, FTAG);
+
 		blkid += tochk;
 		nblks -= tochk;
 	}
 	rw_exit(&dn->dn_struct_rwlock);
 
+	/* account for new level 1 indirect blocks that might show up */
+	if (skipped > 0) {
+		txh->txh_fudge += skipped << dn->dn_indblkshift;
+		skipped = MIN(skipped, DMU_MAX_DELETEBLKCNT >> epbs);
+		txh->txh_memory_tohold += skipped << dn->dn_indblkshift;
+	}
 	txh->txh_space_tofree += space;
+	txh->txh_space_tounref += unref;
 }
 
 void
@@ -466,7 +494,7 @@ dmu_tx_hold_free(dmu_tx_t *tx, uint64_t object, uint64_t off, uint64_t len)
 	/*
 	 * For i/o error checking, read the first and last level-0
 	 * blocks, and all the level-1 blocks.  The above count_write's
-	 * will take care of the level-0 blocks.
+	 * have already taken care of the level-0 blocks.
 	 */
 	if (dn->dn_nlevels > 1) {
 		shift = dn->dn_datablkshift + dn->dn_indblkshift -
@@ -478,7 +506,7 @@ dmu_tx_hold_free(dmu_tx_t *tx, uint64_t object, uint64_t off, uint64_t len)
 		    NULL, NULL, ZIO_FLAG_CANFAIL);
 		for (i = start; i <= end; i++) {
 			uint64_t ibyte = i << shift;
-			err = dnode_next_offset(dn, FALSE, &ibyte, 2, 1, 0);
+			err = dnode_next_offset(dn, 0, &ibyte, 2, 1, 0);
 			i = ibyte >> shift;
 			if (err == ESRCH)
 				break;
@@ -550,10 +578,13 @@ dmu_tx_hold_zap(dmu_tx_t *tx, uint64_t object, int add, char *name)
 		 * the size will change between now and the dbuf dirty call.
 		 */
 		if (dsl_dataset_block_freeable(dn->dn_objset->os_dsl_dataset,
-		    dn->dn_phys->dn_blkptr[0].blk_birth))
+		    dn->dn_phys->dn_blkptr[0].blk_birth)) {
 			txh->txh_space_tooverwrite += SPA_MAXBLOCKSIZE;
-		else
+		} else {
 			txh->txh_space_towrite += SPA_MAXBLOCKSIZE;
+			txh->txh_space_tounref +=
+			    BP_GET_ASIZE(dn->dn_phys->dn_blkptr);
+		}
 		return;
 	}
 
@@ -575,7 +606,7 @@ dmu_tx_hold_zap(dmu_tx_t *tx, uint64_t object, int add, char *name)
 	 * 3 new blocks written if adding: new split leaf, 2 grown ptrtbl blocks
 	 */
 	dmu_tx_count_write(txh, dn->dn_maxblkid * dn->dn_datablksz,
-	    (3 + add ? 3 : 0) << dn->dn_datablkshift);
+	    (3 + (add ? 3 : 0)) << dn->dn_datablkshift);
 
 	/*
 	 * If the modified blocks are scattered to the four winds,
@@ -698,12 +729,13 @@ dmu_tx_dirty_buf(dmu_tx_t *tx, dmu_buf_impl_t *db)
 					match_offset = TRUE;
 				break;
 			case THT_FREE:
-				if (blkid == beginblk &&
-				    (txh->txh_arg1 != 0 ||
-				    dn->dn_maxblkid == 0))
-					match_offset = TRUE;
-				if (blkid == endblk &&
-				    txh->txh_arg2 != DMU_OBJECT_END)
+				/*
+				 * We will dirty all the level 1 blocks in
+				 * the free range and perhaps the first and
+				 * last level 0 block.
+				 */
+				if (blkid >= beginblk && (blkid <= endblk ||
+				    txh->txh_arg2 == DMU_OBJECT_END))
 					match_offset = TRUE;
 				break;
 			case THT_BONUS:
@@ -733,12 +765,32 @@ static int
 dmu_tx_try_assign(dmu_tx_t *tx, uint64_t txg_how)
 {
 	dmu_tx_hold_t *txh;
-	uint64_t lsize, asize, fsize, towrite, tofree, tooverwrite;
+	spa_t *spa = tx->tx_pool->dp_spa;
+	uint64_t memory, asize, fsize, usize;
+	uint64_t towrite, tofree, tooverwrite, tounref, tohold, fudge;
 
 	ASSERT3U(tx->tx_txg, ==, 0);
+
 	if (tx->tx_err)
 		return (tx->tx_err);
 
+	if (spa_suspended(spa)) {
+		/*
+		 * If the user has indicated a blocking failure mode
+		 * then return ERESTART which will block in dmu_tx_wait().
+		 * Otherwise, return EIO so that an error can get
+		 * propagated back to the VOP calls.
+		 *
+		 * Note that we always honor the txg_how flag regardless
+		 * of the failuremode setting.
+		 */
+		if (spa_get_failmode(spa) == ZIO_FAILURE_MODE_CONTINUE &&
+		    txg_how != TXG_WAIT)
+			return (EIO);
+
+		return (ERESTART);
+	}
+
 	tx->tx_txg = txg_hold_open(tx->tx_pool, &tx->tx_txgh);
 	tx->tx_needassign_txh = NULL;
 
@@ -748,7 +800,7 @@ dmu_tx_try_assign(dmu_tx_t *tx, uint64_t txg_how)
 	 * dmu_tx_unassign() logic.
 	 */
 
-	towrite = tofree = tooverwrite = 0;
+	towrite = tofree = tooverwrite = tounref = tohold = fudge = 0;
 	for (txh = list_head(&tx->tx_holds); txh;
 	    txh = list_next(&tx->tx_holds, txh)) {
 		dnode_t *dn = txh->txh_dnode;
@@ -768,6 +820,9 @@ dmu_tx_try_assign(dmu_tx_t *tx, uint64_t txg_how)
 		towrite += txh->txh_space_towrite;
 		tofree += txh->txh_space_tofree;
 		tooverwrite += txh->txh_space_tooverwrite;
+		tounref += txh->txh_space_tounref;
+		tohold += txh->txh_memory_tohold;
+		fudge += txh->txh_fudge;
 	}
 
 	/*
@@ -788,22 +843,31 @@ dmu_tx_try_assign(dmu_tx_t *tx, uint64_t txg_how)
 		tooverwrite = tofree = 0;
 	}
 
-	/*
-	 * Convert logical size to worst-case allocated size.
-	 */
+	/* needed allocation: worst-case estimate of write space */
+	asize = spa_get_asize(tx->tx_pool->dp_spa, towrite + tooverwrite);
+	/* freed space estimate: worst-case overwrite + free estimate */
 	fsize = spa_get_asize(tx->tx_pool->dp_spa, tooverwrite) + tofree;
-	lsize = towrite + tooverwrite;
-	asize = spa_get_asize(tx->tx_pool->dp_spa, lsize);
+	/* convert unrefd space to worst-case estimate */
+	usize = spa_get_asize(tx->tx_pool->dp_spa, tounref);
+	/* calculate memory footprint estimate */
+	memory = towrite + tooverwrite + tohold;
 
 #ifdef ZFS_DEBUG
-	tx->tx_space_towrite = asize;
+	/*
+	 * Add in 'tohold' to account for our dirty holds on this memory
+	 * XXX - the "fudge" factor is to account for skipped blocks that
+	 * we missed because dnode_next_offset() misses in-core-only blocks.
+	 */
+	tx->tx_space_towrite = asize +
+	    spa_get_asize(tx->tx_pool->dp_spa, tohold + fudge);
 	tx->tx_space_tofree = tofree;
 	tx->tx_space_tooverwrite = tooverwrite;
+	tx->tx_space_tounref = tounref;
 #endif
 
 	if (tx->tx_dir && asize != 0) {
-		int err = dsl_dir_tempreserve_space(tx->tx_dir,
-		    lsize, asize, fsize, &tx->tx_tempreserve_cookie, tx);
+		int err = dsl_dir_tempreserve_space(tx->tx_dir, memory,
+		    asize, fsize, usize, &tx->tx_tempreserve_cookie, tx);
 		if (err)
 			return (err);
 	}
@@ -885,10 +949,18 @@ dmu_tx_assign(dmu_tx_t *tx, uint64_t txg_how)
 void
 dmu_tx_wait(dmu_tx_t *tx)
 {
+	spa_t *spa = tx->tx_pool->dp_spa;
+
 	ASSERT(tx->tx_txg == 0);
-	ASSERT(tx->tx_lasttried_txg != 0);
 
-	if (tx->tx_needassign_txh) {
+	/*
+	 * It's possible that the pool has become active after this thread
+	 * has tried to obtain a tx. If that's the case then his
+	 * tx_lasttried_txg would not have been assigned.
+	 */
+	if (spa_suspended(spa) || tx->tx_lasttried_txg == 0) {
+		txg_wait_synced(tx->tx_pool, spa_last_synced_txg(spa) + 1);
+	} else if (tx->tx_needassign_txh) {
 		dnode_t *dn = tx->tx_needassign_txh->txh_dnode;
 
 		mutex_enter(&dn->dn_mtx);
@@ -948,6 +1020,7 @@ dmu_tx_commit(dmu_tx_t *tx)
 
 	if (tx->tx_anyobj == FALSE)
 		txg_rele_to_sync(&tx->tx_txgh);
+	list_destroy(&tx->tx_holds);
 #ifdef ZFS_DEBUG
 	dprintf("towrite=%llu written=%llu tofree=%llu freed=%llu\n",
 	    tx->tx_space_towrite, refcount_count(&tx->tx_space_written),
@@ -975,6 +1048,7 @@ dmu_tx_abort(dmu_tx_t *tx)
 		if (dn != NULL)
 			dnode_rele(dn, tx);
 	}
+	list_destroy(&tx->tx_holds);
 #ifdef ZFS_DEBUG
 	refcount_destroy_many(&tx->tx_space_written,
 	    refcount_count(&tx->tx_space_written));
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_zfetch.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_zfetch.c
index b25cc898c37d..8dba38176527 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_zfetch.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_zfetch.c
@@ -38,10 +38,6 @@
  */
 
 int zfs_prefetch_disable = 0;
-SYSCTL_DECL(_vfs_zfs);
-TUNABLE_INT("vfs.zfs.prefetch_disable", &zfs_prefetch_disable);
-SYSCTL_INT(_vfs_zfs, OID_AUTO, prefetch_disable, CTLFLAG_RDTUN,
-    &zfs_prefetch_disable, 0, "Disable prefetch");
 
 /* max # of streams per zfetch */
 uint32_t	zfetch_max_streams = 8;
@@ -52,6 +48,25 @@ uint32_t	zfetch_block_cap = 256;
 /* number of bytes in a array_read at which we stop prefetching (1Mb) */
 uint64_t	zfetch_array_rd_sz = 1024 * 1024;
 
+SYSCTL_DECL(_vfs_zfs);
+TUNABLE_INT("vfs.zfs.prefetch_disable", &zfs_prefetch_disable);
+SYSCTL_INT(_vfs_zfs, OID_AUTO, prefetch_disable, CTLFLAG_RDTUN,
+    &zfs_prefetch_disable, 0, "Disable prefetch");
+SYSCTL_NODE(_vfs_zfs, OID_AUTO, zfetch, CTLFLAG_RW, 0, "ZFS ZFETCH");
+TUNABLE_INT("vfs.zfs.zfetch.max_streams", &zfetch_max_streams);
+SYSCTL_UINT(_vfs_zfs_zfetch, OID_AUTO, max_streams, CTLFLAG_RDTUN,
+    &zfetch_max_streams, 0, "Max # of streams per zfetch");
+TUNABLE_INT("vfs.zfs.zfetch.min_sec_reap", &zfetch_min_sec_reap);
+SYSCTL_UINT(_vfs_zfs_zfetch, OID_AUTO, min_sec_reap, CTLFLAG_RDTUN,
+    &zfetch_min_sec_reap, 0, "Min time before stream reclaim");
+TUNABLE_INT("vfs.zfs.zfetch.block_cap", &zfetch_block_cap);
+SYSCTL_UINT(_vfs_zfs_zfetch, OID_AUTO, block_cap, CTLFLAG_RDTUN,
+    &zfetch_block_cap, 0, "Max number of blocks to fetch at a time");
+TUNABLE_QUAD("vfs.zfs.zfetch.array_rd_sz", &zfetch_array_rd_sz);
+SYSCTL_QUAD(_vfs_zfs_zfetch, OID_AUTO, array_rd_sz, CTLFLAG_RDTUN,
+    &zfetch_array_rd_sz, 0,
+    "Number of bytes in a array_read at which we stop prefetching");
+
 /* forward decls for static routines */
 static int		dmu_zfetch_colinear(zfetch_t *, zstream_t *);
 static void		dmu_zfetch_dofetch(zfetch_t *, zstream_t *);
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dnode.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dnode.c
index ca502857b1fa..5adbc3c0ff5d 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dnode.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dnode.c
@@ -19,12 +19,10 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
-#pragma ident	"%Z%%M%	%I%	%E% SMI"
-
 #include <sys/zfs_context.h>
 #include <sys/dbuf.h>
 #include <sys/dnode.h>
@@ -242,6 +240,23 @@ free_range_compar(const void *node1, const void *node2)
 	else return (0);
 }
 
+void
+dnode_setbonuslen(dnode_t *dn, int newsize, dmu_tx_t *tx)
+{
+	ASSERT3U(refcount_count(&dn->dn_holds), >=, 1);
+
+	dnode_setdirty(dn, tx);
+	rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
+	ASSERT3U(newsize, <=, DN_MAX_BONUSLEN -
+	    (dn->dn_nblkptr-1) * sizeof (blkptr_t));
+	dn->dn_bonuslen = newsize;
+	if (newsize == 0)
+		dn->dn_next_bonuslen[tx->tx_txg & TXG_MASK] = DN_ZERO_BONUSLEN;
+	else
+		dn->dn_next_bonuslen[tx->tx_txg & TXG_MASK] = dn->dn_bonuslen;
+	rw_exit(&dn->dn_struct_rwlock);
+}
+
 static void
 dnode_setdblksz(dnode_t *dn, int size)
 {
@@ -285,6 +300,7 @@ dnode_create(objset_impl_t *os, dnode_phys_t *dnp, dmu_buf_impl_t *db,
 	list_insert_head(&os->os_dnodes, dn);
 	mutex_exit(&os->os_lock);
 
+	arc_space_consume(sizeof (dnode_t));
 	return (dn);
 }
 
@@ -319,6 +335,7 @@ dnode_destroy(dnode_t *dn)
 		dn->dn_bonus = NULL;
 	}
 	kmem_cache_free(dnode_cache, dn);
+	arc_space_return(sizeof (dnode_t));
 }
 
 void
@@ -362,6 +379,7 @@ dnode_allocate(dnode_t *dn, dmu_object_type_t ot, int blocksize, int ibs,
 	for (i = 0; i < TXG_SIZE; i++) {
 		ASSERT3U(dn->dn_next_nlevels[i], ==, 0);
 		ASSERT3U(dn->dn_next_indblkshift[i], ==, 0);
+		ASSERT3U(dn->dn_next_bonuslen[i], ==, 0);
 		ASSERT3U(dn->dn_next_blksz[i], ==, 0);
 		ASSERT(!list_link_active(&dn->dn_dirty_link[i]));
 		ASSERT3P(list_head(&dn->dn_dirty_records[i]), ==, NULL);
@@ -389,6 +407,7 @@ dnode_allocate(dnode_t *dn, dmu_object_type_t ot, int blocksize, int ibs,
 
 	dnode_setdirty(dn, tx);
 	dn->dn_next_indblkshift[tx->tx_txg & TXG_MASK] = ibs;
+	dn->dn_next_bonuslen[tx->tx_txg & TXG_MASK] = dn->dn_bonuslen;
 	dn->dn_next_blksz[tx->tx_txg & TXG_MASK] = dn->dn_datablksz;
 }
 
@@ -396,7 +415,7 @@ void
 dnode_reallocate(dnode_t *dn, dmu_object_type_t ot, int blocksize,
     dmu_object_type_t bonustype, int bonuslen, dmu_tx_t *tx)
 {
-	int i;
+	int i, old_nblkptr;
 	dmu_buf_impl_t *db = NULL;
 
 	ASSERT3U(blocksize, >=, SPA_MINBLOCKSIZE);
@@ -413,7 +432,7 @@ dnode_reallocate(dnode_t *dn, dmu_object_type_t ot, int blocksize,
 		ASSERT(!list_link_active(&dn->dn_dirty_link[i]));
 
 	/* clean up any unreferenced dbufs */
-	(void) dnode_evict_dbufs(dn, 0);
+	dnode_evict_dbufs(dn);
 	ASSERT3P(list_head(&dn->dn_dbufs), ==, NULL);
 
 	/*
@@ -436,38 +455,18 @@ dnode_reallocate(dnode_t *dn, dmu_object_type_t ot, int blocksize,
 	}
 	dnode_setdblksz(dn, blocksize);
 	dnode_setdirty(dn, tx);
+	dn->dn_next_bonuslen[tx->tx_txg&TXG_MASK] = bonuslen;
 	dn->dn_next_blksz[tx->tx_txg&TXG_MASK] = blocksize;
 	rw_exit(&dn->dn_struct_rwlock);
-	if (db) {
+	if (db)
 		dbuf_rele(db, FTAG);
-		db = NULL;
-	}
 
 	/* change type */
 	dn->dn_type = ot;
 
-	if (dn->dn_bonuslen != bonuslen) {
-		/* change bonus size */
-		if (bonuslen == 0)
-			bonuslen = 1; /* XXX */
-		rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
-		if (dn->dn_bonus == NULL)
-			dn->dn_bonus = dbuf_create_bonus(dn);
-		db = dn->dn_bonus;
-		rw_exit(&dn->dn_struct_rwlock);
-		if (refcount_add(&db->db_holds, FTAG) == 1)
-			dnode_add_ref(dn, db);
-		VERIFY(0 == dbuf_read(db, NULL, DB_RF_MUST_SUCCEED));
-		mutex_enter(&db->db_mtx);
-		ASSERT3U(db->db.db_size, ==, dn->dn_bonuslen);
-		ASSERT(db->db.db_data != NULL);
-		db->db.db_size = bonuslen;
-		mutex_exit(&db->db_mtx);
-		(void) dbuf_dirty(db, tx);
-	}
-
 	/* change bonus size and type */
 	mutex_enter(&dn->dn_mtx);
+	old_nblkptr = dn->dn_nblkptr;
 	dn->dn_bonustype = bonustype;
 	dn->dn_bonuslen = bonuslen;
 	dn->dn_nblkptr = 1 + ((DN_MAX_BONUSLEN - bonuslen) >> SPA_BLKPTRSHIFT);
@@ -475,12 +474,15 @@ dnode_reallocate(dnode_t *dn, dmu_object_type_t ot, int blocksize,
 	dn->dn_compress = ZIO_COMPRESS_INHERIT;
 	ASSERT3U(dn->dn_nblkptr, <=, DN_MAX_NBLKPTR);
 
-	/*
-	 * NB: we have to do the dbuf_rele after we've changed the
-	 * dn_bonuslen, for the sake of dbuf_verify().
-	 */
-	if (db)
-		dbuf_rele(db, FTAG);
+	/* XXX - for now, we can't make nblkptr smaller */
+	ASSERT3U(dn->dn_nblkptr, >=, old_nblkptr);
+
+	/* fix up the bonus db_size if dn_nblkptr has changed */
+	if (dn->dn_bonus && dn->dn_bonuslen != old_nblkptr) {
+		dn->dn_bonus->db.db_size =
+		    DN_MAX_BONUSLEN - (dn->dn_nblkptr-1) * sizeof (blkptr_t);
+		ASSERT(dn->dn_bonuslen <= dn->dn_bonus->db.db_size);
+	}
 
 	dn->dn_allocated_txg = tx->tx_txg;
 	mutex_exit(&dn->dn_mtx);
@@ -559,6 +561,12 @@ dnode_hold_impl(objset_impl_t *os, uint64_t object, int flag,
 	dmu_buf_impl_t *db;
 	dnode_t **children_dnodes;
 
+	/*
+	 * If you are holding the spa config lock as writer, you shouldn't
+	 * be asking the DMU to do *anything*.
+	 */
+	ASSERT(spa_config_held(os->os_spa, SCL_ALL, RW_WRITER) == 0);
+
 	if (object == 0 || object >= DN_MAX_OBJECT)
 		return (EINVAL);
 
@@ -602,9 +610,10 @@ dnode_hold_impl(objset_impl_t *os, uint64_t object, int flag,
 	}
 
 	if ((dn = children_dnodes[idx]) == NULL) {
+		dnode_phys_t *dnp = (dnode_phys_t *)db->db.db_data+idx;
 		dnode_t *winner;
-		dn = dnode_create(os, (dnode_phys_t *)db->db.db_data+idx,
-			db, object);
+
+		dn = dnode_create(os, dnp, db, object);
 		winner = atomic_cas_ptr(&children_dnodes[idx], NULL, dn);
 		if (winner != NULL) {
 			dnode_destroy(dn);
@@ -644,11 +653,22 @@ dnode_hold(objset_impl_t *os, uint64_t object, void *tag, dnode_t **dnp)
 	return (dnode_hold_impl(os, object, DNODE_MUST_BE_ALLOCATED, tag, dnp));
 }
 
-void
+/*
+ * Can only add a reference if there is already at least one
+ * reference on the dnode.  Returns FALSE if unable to add a
+ * new reference.
+ */
+boolean_t
 dnode_add_ref(dnode_t *dn, void *tag)
 {
-	ASSERT(refcount_count(&dn->dn_holds) > 0);
-	(void) refcount_add(&dn->dn_holds, tag);
+	mutex_enter(&dn->dn_mtx);
+	if (refcount_is_zero(&dn->dn_holds)) {
+		mutex_exit(&dn->dn_mtx);
+		return (FALSE);
+	}
+	VERIFY(1 < refcount_add(&dn->dn_holds, tag));
+	mutex_exit(&dn->dn_mtx);
+	return (TRUE);
 }
 
 void
@@ -656,7 +676,9 @@ dnode_rele(dnode_t *dn, void *tag)
 {
 	uint64_t refs;
 
+	mutex_enter(&dn->dn_mtx);
 	refs = refcount_remove(&dn->dn_holds, tag);
+	mutex_exit(&dn->dn_mtx);
 	/* NOTE: the DNODE_DNODE does not have a dn_dbuf */
 	if (refs == 0 && dn->dn_dbuf)
 		dbuf_rele(dn->dn_dbuf, dn);
@@ -692,6 +714,7 @@ dnode_setdirty(dnode_t *dn, dmu_tx_t *tx)
 
 	ASSERT(!refcount_is_zero(&dn->dn_holds) || list_head(&dn->dn_dbufs));
 	ASSERT(dn->dn_datablksz != 0);
+	ASSERT3U(dn->dn_next_bonuslen[txg&TXG_MASK], ==, 0);
 	ASSERT3U(dn->dn_next_blksz[txg&TXG_MASK], ==, 0);
 
 	dprintf_ds(os->os_dsl_dataset, "obj=%llu txg=%llu\n",
@@ -714,7 +737,7 @@ dnode_setdirty(dnode_t *dn, dmu_tx_t *tx)
 	 * dnode will hang around after we finish processing its
 	 * children.
 	 */
-	dnode_add_ref(dn, (void *)(uintptr_t)tx->tx_txg);
+	VERIFY(dnode_add_ref(dn, (void *)(uintptr_t)tx->tx_txg));
 
 	(void) dbuf_dirty(dn->dn_dbuf, tx);
 
@@ -762,7 +785,7 @@ int
 dnode_set_blksz(dnode_t *dn, uint64_t size, int ibs, dmu_tx_t *tx)
 {
 	dmu_buf_impl_t *db, *db_next;
-	int have_db0 = FALSE;
+	int err;
 
 	if (size == 0)
 		size = SPA_MINBLOCKSIZE;
@@ -787,9 +810,7 @@ dnode_set_blksz(dnode_t *dn, uint64_t size, int ibs, dmu_tx_t *tx)
 	for (db = list_head(&dn->dn_dbufs); db; db = db_next) {
 		db_next = list_next(&dn->dn_dbufs, db);
 
-		if (db->db_blkid == 0) {
-			have_db0 = TRUE;
-		} else if (db->db_blkid != DB_BONUS_BLKID) {
+		if (db->db_blkid != 0 && db->db_blkid != DB_BONUS_BLKID) {
 			mutex_exit(&dn->dn_dbufs_mtx);
 			goto fail;
 		}
@@ -799,12 +820,12 @@ dnode_set_blksz(dnode_t *dn, uint64_t size, int ibs, dmu_tx_t *tx)
 	if (ibs && dn->dn_nlevels != 1)
 		goto fail;
 
-	db = NULL;
-	if (!BP_IS_HOLE(&dn->dn_phys->dn_blkptr[0]) || have_db0) {
-		/* obtain the old block */
-		db = dbuf_hold(dn, 0, FTAG);
+	/* resize the old block */
+	err = dbuf_hold_impl(dn, 0, 0, TRUE, FTAG, &db);
+	if (err == 0)
 		dbuf_new_size(db, size, tx);
-	}
+	else if (err != ENOENT)
+		goto fail;
 
 	dnode_setdblksz(dn, size);
 	dnode_setdirty(dn, tx);
@@ -813,7 +834,7 @@ dnode_set_blksz(dnode_t *dn, uint64_t size, int ibs, dmu_tx_t *tx)
 		dn->dn_indblkshift = ibs;
 		dn->dn_next_indblkshift[tx->tx_txg&TXG_MASK] = ibs;
 	}
-
+	/* rele after we have fixed the blocksize in the dnode */
 	if (db)
 		dbuf_rele(db, FTAG);
 
@@ -825,19 +846,32 @@ fail:
 	return (ENOTSUP);
 }
 
+/* read-holding callers must not rely on the lock being continuously held */
 void
-dnode_new_blkid(dnode_t *dn, uint64_t blkid, dmu_tx_t *tx)
+dnode_new_blkid(dnode_t *dn, uint64_t blkid, dmu_tx_t *tx, boolean_t have_read)
 {
 	uint64_t txgoff = tx->tx_txg & TXG_MASK;
-	int drop_struct_lock = FALSE;
 	int epbs, new_nlevels;
 	uint64_t sz;
 
 	ASSERT(blkid != DB_BONUS_BLKID);
 
-	if (!RW_WRITE_HELD(&dn->dn_struct_rwlock)) {
-		rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
-		drop_struct_lock = TRUE;
+	ASSERT(have_read ?
+	    RW_READ_HELD(&dn->dn_struct_rwlock) :
+	    RW_WRITE_HELD(&dn->dn_struct_rwlock));
+
+	/*
+	 * if we have a read-lock, check to see if we need to do any work
+	 * before upgrading to a write-lock.
+	 */
+	if (have_read) {
+		if (blkid <= dn->dn_maxblkid)
+			return;
+
+		if (!rw_tryupgrade(&dn->dn_struct_rwlock)) {
+			rw_exit(&dn->dn_struct_rwlock);
+			rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
+		}
 	}
 
 	if (blkid <= dn->dn_maxblkid)
@@ -889,8 +923,8 @@ dnode_new_blkid(dnode_t *dn, uint64_t blkid, dmu_tx_t *tx)
 	}
 
 out:
-	if (drop_struct_lock)
-		rw_exit(&dn->dn_struct_rwlock);
+	if (have_read)
+		rw_downgrade(&dn->dn_struct_rwlock);
 }
 
 void
@@ -951,15 +985,15 @@ dnode_free_range(dnode_t *dn, uint64_t off, uint64_t len, dmu_tx_t *tx)
 {
 	dmu_buf_impl_t *db;
 	uint64_t blkoff, blkid, nblks;
-	int blksz, head;
+	int blksz, blkshift, head, tail;
 	int trunc = FALSE;
+	int epbs;
 
 	rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
 	blksz = dn->dn_datablksz;
+	blkshift = dn->dn_datablkshift;
+	epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT;
 
-	/* If the range is past the end of the file, this is a no-op */
-	if (off >= blksz * (dn->dn_maxblkid+1))
-		goto out;
 	if (len == -1ULL) {
 		len = UINT64_MAX - off;
 		trunc = TRUE;
@@ -971,11 +1005,18 @@ dnode_free_range(dnode_t *dn, uint64_t off, uint64_t len, dmu_tx_t *tx)
 	if (ISP2(blksz)) {
 		head = P2NPHASE(off, blksz);
 		blkoff = P2PHASE(off, blksz);
+		if ((off >> blkshift) > dn->dn_maxblkid)
+			goto out;
 	} else {
 		ASSERT(dn->dn_maxblkid == 0);
 		if (off == 0 && len >= blksz) {
-			/* Freeing the whole block; don't do any head. */
-			head = 0;
+			/* Freeing the whole block; fast-track this request */
+			blkid = 0;
+			nblks = 1;
+			goto done;
+		} else if (off >= blksz) {
+			/* Freeing past end-of-data */
+			goto out;
 		} else {
 			/* Freeing part of the block. */
 			head = blksz - off;
@@ -1008,88 +1049,95 @@ dnode_free_range(dnode_t *dn, uint64_t off, uint64_t len, dmu_tx_t *tx)
 	}
 
 	/* If the range was less than one block, we're done */
-	if (len == 0 || off >= blksz * (dn->dn_maxblkid+1))
+	if (len == 0)
 		goto out;
 
-	if (!ISP2(blksz)) {
-		/*
-		 * They are freeing the whole block of a
-		 * non-power-of-two blocksize file.  Skip all the messy
-		 * math.
-		 */
-		ASSERT3U(off, ==, 0);
-		ASSERT3U(len, >=, blksz);
-		blkid = 0;
-		nblks = 1;
-	} else {
-		int tail;
-		int epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT;
-		int blkshift = dn->dn_datablkshift;
-
-		/* If the remaining range is past end of file, we're done */
-		if (off > dn->dn_maxblkid << blkshift)
-			goto out;
+	/* If the remaining range is past end of file, we're done */
+	if ((off >> blkshift) > dn->dn_maxblkid)
+		goto out;
 
-		if (off + len == UINT64_MAX)
-			tail = 0;
-		else
-			tail = P2PHASE(len, blksz);
-
-		ASSERT3U(P2PHASE(off, blksz), ==, 0);
-		/* zero out any partial block data at the end of the range */
-		if (tail) {
-			if (len < tail)
-				tail = len;
-			if (dbuf_hold_impl(dn, 0, dbuf_whichblock(dn, off+len),
-			    TRUE, FTAG, &db) == 0) {
-				/* don't dirty if not on disk and not dirty */
-				if (db->db_last_dirty ||
-				    (db->db_blkptr &&
-				    !BP_IS_HOLE(db->db_blkptr))) {
-					rw_exit(&dn->dn_struct_rwlock);
-					dbuf_will_dirty(db, tx);
-					rw_enter(&dn->dn_struct_rwlock,
-					    RW_WRITER);
-					bzero(db->db.db_data, tail);
-				}
-				dbuf_rele(db, FTAG);
+	ASSERT(ISP2(blksz));
+	if (trunc)
+		tail = 0;
+	else
+		tail = P2PHASE(len, blksz);
+
+	ASSERT3U(P2PHASE(off, blksz), ==, 0);
+	/* zero out any partial block data at the end of the range */
+	if (tail) {
+		if (len < tail)
+			tail = len;
+		if (dbuf_hold_impl(dn, 0, dbuf_whichblock(dn, off+len),
+		    TRUE, FTAG, &db) == 0) {
+			/* don't dirty if not on disk and not dirty */
+			if (db->db_last_dirty ||
+			    (db->db_blkptr && !BP_IS_HOLE(db->db_blkptr))) {
+				rw_exit(&dn->dn_struct_rwlock);
+				dbuf_will_dirty(db, tx);
+				rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
+				bzero(db->db.db_data, tail);
 			}
-			len -= tail;
+			dbuf_rele(db, FTAG);
 		}
-		/* If the range did not include a full block, we are done */
-		if (len == 0)
-			goto out;
+		len -= tail;
+	}
 
-		/* dirty the left indirects */
-		if (dn->dn_nlevels > 1 && off != 0) {
-			db = dbuf_hold_level(dn, 1,
-			    (off - head) >> (blkshift + epbs), FTAG);
+	/* If the range did not include a full block, we are done */
+	if (len == 0)
+		goto out;
+
+	ASSERT(IS_P2ALIGNED(off, blksz));
+	ASSERT(trunc || IS_P2ALIGNED(len, blksz));
+	blkid = off >> blkshift;
+	nblks = len >> blkshift;
+	if (trunc)
+		nblks += 1;
+
+	/*
+	 * Read in and mark all the level-1 indirects dirty,
+	 * so that they will stay in memory until syncing phase.
+	 * Always dirty the first and last indirect to make sure
+	 * we dirty all the partial indirects.
+	 */
+	if (dn->dn_nlevels > 1) {
+		uint64_t i, first, last;
+		int shift = epbs + dn->dn_datablkshift;
+
+		first = blkid >> epbs;
+		if (db = dbuf_hold_level(dn, 1, first, FTAG)) {
 			dbuf_will_dirty(db, tx);
 			dbuf_rele(db, FTAG);
 		}
-
-		/* dirty the right indirects */
-		if (dn->dn_nlevels > 1 && !trunc) {
-			db = dbuf_hold_level(dn, 1,
-			    (off + len + tail - 1) >> (blkshift + epbs), FTAG);
+		if (trunc)
+			last = dn->dn_maxblkid >> epbs;
+		else
+			last = (blkid + nblks - 1) >> epbs;
+		if (last > first && (db = dbuf_hold_level(dn, 1, last, FTAG))) {
 			dbuf_will_dirty(db, tx);
 			dbuf_rele(db, FTAG);
 		}
-
-		/*
-		 * Finally, add this range to the dnode range list, we
-		 * will finish up this free operation in the syncing phase.
-		 */
-		ASSERT(IS_P2ALIGNED(off, 1<<blkshift));
-		ASSERT(off + len == UINT64_MAX ||
-		    IS_P2ALIGNED(len, 1<<blkshift));
-		blkid = off >> blkshift;
-		nblks = len >> blkshift;
-
-		if (trunc)
-			dn->dn_maxblkid = (blkid ? blkid - 1 : 0);
+		for (i = first + 1; i < last; i++) {
+			uint64_t ibyte = i << shift;
+			int err;
+
+			err = dnode_next_offset(dn,
+			    DNODE_FIND_HAVELOCK, &ibyte, 1, 1, 0);
+			i = ibyte >> shift;
+			if (err == ESRCH || i >= last)
+				break;
+			ASSERT(err == 0);
+			db = dbuf_hold_level(dn, 1, i, FTAG);
+			if (db) {
+				dbuf_will_dirty(db, tx);
+				dbuf_rele(db, FTAG);
+			}
+		}
 	}
-
+done:
+	/*
+	 * Add this range to the dnode range list.
+	 * We will finish up this free operation in the syncing phase.
+	 */
 	mutex_enter(&dn->dn_mtx);
 	dnode_clear_range(dn, blkid, nblks, tx);
 	{
@@ -1109,9 +1157,12 @@ dnode_free_range(dnode_t *dn, uint64_t off, uint64_t len, dmu_tx_t *tx)
 	}
 	mutex_exit(&dn->dn_mtx);
 
-	dbuf_free_range(dn, blkid, nblks, tx);
+	dbuf_free_range(dn, blkid, blkid + nblks - 1, tx);
 	dnode_setdirty(dn, tx);
 out:
+	if (trunc && dn->dn_maxblkid >= (off >> blkshift))
+		dn->dn_maxblkid = (off >> blkshift ? (off >> blkshift) - 1 : 0);
+
 	rw_exit(&dn->dn_struct_rwlock);
 }
 
@@ -1179,7 +1230,7 @@ dnode_diduse_space(dnode_t *dn, int64_t delta)
 		ASSERT3U(space, >=, -delta); /* no underflow */
 	}
 	space += delta;
-	if (spa_version(dn->dn_objset->os_spa) < ZFS_VERSION_DNODE_BYTES) {
+	if (spa_version(dn->dn_objset->os_spa) < SPA_VERSION_DNODE_BYTES) {
 		ASSERT((dn->dn_phys->dn_flags & DNODE_FLAG_USED_BYTES) == 0);
 		ASSERT3U(P2PHASE(space, 1<<DEV_BSHIFT), ==, 0);
 		dn->dn_phys->dn_used = space >> DEV_BSHIFT;
@@ -1211,7 +1262,7 @@ dnode_willuse_space(dnode_t *dn, int64_t space, dmu_tx_t *tx)
 }
 
 static int
-dnode_next_offset_level(dnode_t *dn, boolean_t hole, uint64_t *offset,
+dnode_next_offset_level(dnode_t *dn, int flags, uint64_t *offset,
 	int lvl, uint64_t blkfill, uint64_t txg)
 {
 	dmu_buf_impl_t *db = NULL;
@@ -1219,11 +1270,16 @@ dnode_next_offset_level(dnode_t *dn, boolean_t hole, uint64_t *offset,
 	uint64_t epbs = dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT;
 	uint64_t epb = 1ULL << epbs;
 	uint64_t minfill, maxfill;
-	int i, error, span;
+	boolean_t hole;
+	int i, inc, error, span;
 
 	dprintf("probing object %llu offset %llx level %d of %u\n",
 	    dn->dn_object, *offset, lvl, dn->dn_phys->dn_nlevels);
 
+	hole = flags & DNODE_FIND_HOLE;
+	inc = (flags & DNODE_FIND_BACKWARDS) ? -1 : 1;
+	ASSERT(txg == 0 || !hole);
+
 	if (lvl == dn->dn_phys->dn_nlevels) {
 		error = 0;
 		epb = dn->dn_phys->dn_nblkptr;
@@ -1232,9 +1288,18 @@ dnode_next_offset_level(dnode_t *dn, boolean_t hole, uint64_t *offset,
 		uint64_t blkid = dbuf_whichblock(dn, *offset) >> (epbs * lvl);
 		error = dbuf_hold_impl(dn, lvl, blkid, TRUE, FTAG, &db);
 		if (error) {
-			if (error == ENOENT)
-				return (hole ? 0 : ESRCH);
-			return (error);
+			if (error != ENOENT)
+				return (error);
+			if (hole)
+				return (0);
+			/*
+			 * This can only happen when we are searching up
+			 * the block tree for data.  We don't really need to
+			 * adjust the offset, as we will just end up looking
+			 * at the pointer to this block in its parent, and its
+			 * going to be unallocated, so we will skip over it.
+			 */
+			return (ESRCH);
 		}
 		error = dbuf_read(db, NULL, DB_RF_CANFAIL | DB_RF_HAVESTRUCT);
 		if (error) {
@@ -1246,13 +1311,18 @@ dnode_next_offset_level(dnode_t *dn, boolean_t hole, uint64_t *offset,
 
 	if (db && txg &&
 	    (db->db_blkptr == NULL || db->db_blkptr->blk_birth <= txg)) {
+		/*
+		 * This can only happen when we are searching up the tree
+		 * and these conditions mean that we need to keep climbing.
+		 */
 		error = ESRCH;
 	} else if (lvl == 0) {
 		dnode_phys_t *dnp = data;
 		span = DNODE_SHIFT;
 		ASSERT(dn->dn_type == DMU_OT_DNODE);
 
-		for (i = (*offset >> span) & (blkfill - 1); i < blkfill; i++) {
+		for (i = (*offset >> span) & (blkfill - 1);
+		    i >= 0 && i < blkfill; i += inc) {
 			boolean_t newcontents = B_TRUE;
 			if (txg) {
 				int j;
@@ -1264,9 +1334,9 @@ dnode_next_offset_level(dnode_t *dn, boolean_t hole, uint64_t *offset,
 			}
 			if (!dnp[i].dn_type == hole && newcontents)
 				break;
-			*offset += 1ULL << span;
+			*offset += (1ULL << span) * inc;
 		}
-		if (i == blkfill)
+		if (i < 0 || i == blkfill)
 			error = ESRCH;
 	} else {
 		blkptr_t *bp = data;
@@ -1280,14 +1350,17 @@ dnode_next_offset_level(dnode_t *dn, boolean_t hole, uint64_t *offset,
 			minfill++;
 
 		for (i = (*offset >> span) & ((1ULL << epbs) - 1);
-		    i < epb; i++) {
+		    i >= 0 && i < epb; i += inc) {
 			if (bp[i].blk_fill >= minfill &&
 			    bp[i].blk_fill <= maxfill &&
-			    bp[i].blk_birth > txg)
+			    (hole || bp[i].blk_birth > txg))
 				break;
-			*offset += 1ULL << span;
+			if (inc < 0 && *offset < (1ULL << span))
+				*offset = 0;
+			else
+				*offset += (1ULL << span) * inc;
 		}
-		if (i >= epb)
+		if (i < 0 || i == epb)
 			error = ESRCH;
 	}
 
@@ -1306,64 +1379,66 @@ dnode_next_offset_level(dnode_t *dn, boolean_t hole, uint64_t *offset,
  *
  * Examples:
  *
- * dnode_next_offset(dn, hole, offset, 1, 1, 0);
- *	Finds the next hole/data in a file.
+ * dnode_next_offset(dn, flags, offset, 1, 1, 0);
+ *	Finds the next/previous hole/data in a file.
  *	Used in dmu_offset_next().
  *
- * dnode_next_offset(mdn, hole, offset, 0, DNODES_PER_BLOCK, txg);
+ * dnode_next_offset(mdn, flags, offset, 0, DNODES_PER_BLOCK, txg);
  *	Finds the next free/allocated dnode an objset's meta-dnode.
  *	Only finds objects that have new contents since txg (ie.
  *	bonus buffer changes and content removal are ignored).
  *	Used in dmu_object_next().
  *
- * dnode_next_offset(mdn, TRUE, offset, 2, DNODES_PER_BLOCK >> 2, 0);
+ * dnode_next_offset(mdn, DNODE_FIND_HOLE, offset, 2, DNODES_PER_BLOCK >> 2, 0);
  *	Finds the next L2 meta-dnode bp that's at most 1/4 full.
  *	Used in dmu_object_alloc().
  */
 int
-dnode_next_offset(dnode_t *dn, boolean_t hole, uint64_t *offset,
+dnode_next_offset(dnode_t *dn, int flags, uint64_t *offset,
     int minlvl, uint64_t blkfill, uint64_t txg)
 {
+	uint64_t initial_offset = *offset;
 	int lvl, maxlvl;
 	int error = 0;
-	uint64_t initial_offset = *offset;
 
-	rw_enter(&dn->dn_struct_rwlock, RW_READER);
+	if (!(flags & DNODE_FIND_HAVELOCK))
+		rw_enter(&dn->dn_struct_rwlock, RW_READER);
 
 	if (dn->dn_phys->dn_nlevels == 0) {
-		rw_exit(&dn->dn_struct_rwlock);
-		return (ESRCH);
+		error = ESRCH;
+		goto out;
 	}
 
 	if (dn->dn_datablkshift == 0) {
 		if (*offset < dn->dn_datablksz) {
-			if (hole)
+			if (flags & DNODE_FIND_HOLE)
 				*offset = dn->dn_datablksz;
 		} else {
 			error = ESRCH;
 		}
-		rw_exit(&dn->dn_struct_rwlock);
-		return (error);
+		goto out;
 	}
 
 	maxlvl = dn->dn_phys->dn_nlevels;
 
 	for (lvl = minlvl; lvl <= maxlvl; lvl++) {
 		error = dnode_next_offset_level(dn,
-		    hole, offset, lvl, blkfill, txg);
+		    flags, offset, lvl, blkfill, txg);
 		if (error != ESRCH)
 			break;
 	}
 
-	while (--lvl >= minlvl && error == 0) {
+	while (error == 0 && --lvl >= minlvl) {
 		error = dnode_next_offset_level(dn,
-		    hole, offset, lvl, blkfill, txg);
+		    flags, offset, lvl, blkfill, txg);
 	}
 
-	rw_exit(&dn->dn_struct_rwlock);
-
-	if (error == 0 && initial_offset > *offset)
+	if (error == 0 && (flags & DNODE_FIND_BACKWARDS ?
+	    initial_offset < *offset : initial_offset > *offset))
 		error = ESRCH;
+out:
+	if (!(flags & DNODE_FIND_HAVELOCK))
+		rw_exit(&dn->dn_struct_rwlock);
 
 	return (error);
 }
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dnode_sync.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dnode_sync.c
index 9e8c7adbda01..a46d4e70abc8 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dnode_sync.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dnode_sync.c
@@ -19,7 +19,7 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
@@ -55,9 +55,8 @@ dnode_increase_indirection(dnode_t *dn, dmu_tx_t *tx)
 	ASSERT(db != NULL);
 
 	dn->dn_phys->dn_nlevels = new_level;
-	dprintf("os=%p obj=%llu, increase to %d\n",
-		dn->dn_objset, dn->dn_object,
-		dn->dn_phys->dn_nlevels);
+	dprintf("os=%p obj=%llu, increase to %d\n", dn->dn_objset,
+	    dn->dn_object, dn->dn_phys->dn_nlevels);
 
 	/* check for existing blkptrs in the dnode */
 	for (i = 0; i < nblkptr; i++)
@@ -110,25 +109,26 @@ dnode_increase_indirection(dnode_t *dn, dmu_tx_t *tx)
 	rw_exit(&dn->dn_struct_rwlock);
 }
 
-static void
+static int
 free_blocks(dnode_t *dn, blkptr_t *bp, int num, dmu_tx_t *tx)
 {
-	objset_impl_t *os = dn->dn_objset;
+	dsl_dataset_t *ds = dn->dn_objset->os_dsl_dataset;
 	uint64_t bytesfreed = 0;
-	int i;
+	int i, blocks_freed = 0;
 
-	dprintf("os=%p obj=%llx num=%d\n", os, dn->dn_object, num);
+	dprintf("ds=%p obj=%llx num=%d\n", ds, dn->dn_object, num);
 
 	for (i = 0; i < num; i++, bp++) {
 		if (BP_IS_HOLE(bp))
 			continue;
 
-		bytesfreed += bp_get_dasize(os->os_spa, bp);
+		bytesfreed += dsl_dataset_block_kill(ds, bp, dn->dn_zio, tx);
 		ASSERT3U(bytesfreed, <=, DN_USED_BYTES(dn->dn_phys));
-		dsl_dataset_block_kill(os->os_dsl_dataset, bp, dn->dn_zio, tx);
 		bzero(bp, sizeof (blkptr_t));
+		blocks_freed += 1;
 	}
 	dnode_diduse_space(dn, -bytesfreed);
+	return (blocks_freed);
 }
 
 #ifdef ZFS_DEBUG
@@ -160,7 +160,7 @@ free_verify(dmu_buf_impl_t *db, uint64_t start, uint64_t end, dmu_tx_t *tx)
 
 		rw_enter(&db->db_dnode->dn_struct_rwlock, RW_READER);
 		err = dbuf_hold_impl(db->db_dnode, db->db_level-1,
-			(db->db_blkid << epbs) + i, TRUE, FTAG, &child);
+		    (db->db_blkid << epbs) + i, TRUE, FTAG, &child);
 		rw_exit(&db->db_dnode->dn_struct_rwlock);
 		if (err == ENOENT)
 			continue;
@@ -178,7 +178,7 @@ free_verify(dmu_buf_impl_t *db, uint64_t start, uint64_t end, dmu_tx_t *tx)
 				if (buf[j] != 0) {
 					panic("freed data not zero: "
 					    "child=%p i=%d off=%d num=%d\n",
-					    child, i, off, num);
+					    (void *)child, i, off, num);
 				}
 			}
 		}
@@ -195,7 +195,7 @@ free_verify(dmu_buf_impl_t *db, uint64_t start, uint64_t end, dmu_tx_t *tx)
 				if (buf[j] != 0) {
 					panic("freed data not zero: "
 					    "child=%p i=%d off=%d num=%d\n",
-					    child, i, off, num);
+					    (void *)child, i, off, num);
 				}
 			}
 		}
@@ -206,6 +206,8 @@ free_verify(dmu_buf_impl_t *db, uint64_t start, uint64_t end, dmu_tx_t *tx)
 }
 #endif
 
+#define	ALL -1
+
 static int
 free_children(dmu_buf_impl_t *db, uint64_t blkid, uint64_t nblks, int trunc,
     dmu_tx_t *tx)
@@ -216,8 +218,18 @@ free_children(dmu_buf_impl_t *db, uint64_t blkid, uint64_t nblks, int trunc,
 	uint64_t start, end, dbstart, dbend, i;
 	int epbs, shift, err;
 	int all = TRUE;
+	int blocks_freed = 0;
+
+	/*
+	 * There is a small possibility that this block will not be cached:
+	 *   1 - if level > 1 and there are no children with level <= 1
+	 *   2 - if we didn't get a dirty hold (because this block had just
+	 *	 finished being written -- and so had no holds), and then this
+	 *	 block got evicted before we got here.
+	 */
+	if (db->db_state != DB_CACHED)
+		(void) dbuf_read(db, NULL, DB_RF_MUST_SUCCEED);
 
-	(void) dbuf_read(db, NULL, DB_RF_MUST_SUCCEED);
 	arc_release(db->db_buf, db);
 	bp = (blkptr_t *)db->db.db_data;
 
@@ -241,10 +253,10 @@ free_children(dmu_buf_impl_t *db, uint64_t blkid, uint64_t nblks, int trunc,
 
 	if (db->db_level == 1) {
 		FREE_VERIFY(db, start, end, tx);
-		free_blocks(dn, bp, end-start+1, tx);
+		blocks_freed = free_blocks(dn, bp, end-start+1, tx);
 		arc_buf_freeze(db->db_buf);
-		ASSERT(all || db->db_last_dirty);
-		return (all);
+		ASSERT(all || blocks_freed == 0 || db->db_last_dirty);
+		return (all ? ALL : blocks_freed);
 	}
 
 	for (i = start; i <= end; i++, bp++) {
@@ -255,9 +267,9 @@ free_children(dmu_buf_impl_t *db, uint64_t blkid, uint64_t nblks, int trunc,
 		ASSERT3U(err, ==, 0);
 		rw_exit(&dn->dn_struct_rwlock);
 
-		if (free_children(subdb, blkid, nblks, trunc, tx)) {
+		if (free_children(subdb, blkid, nblks, trunc, tx) == ALL) {
 			ASSERT3P(subdb->db_blkptr, ==, bp);
-			free_blocks(dn, bp, 1, tx);
+			blocks_freed += free_blocks(dn, bp, 1, tx);
 		} else {
 			all = FALSE;
 		}
@@ -274,8 +286,8 @@ free_children(dmu_buf_impl_t *db, uint64_t blkid, uint64_t nblks, int trunc,
 		ASSERT3U(bp->blk_birth, ==, 0);
 	}
 #endif
-	ASSERT(all || db->db_last_dirty);
-	return (all);
+	ASSERT(all || blocks_freed == 0 || db->db_last_dirty);
+	return (all ? ALL : blocks_freed);
 }
 
 /*
@@ -305,15 +317,14 @@ dnode_sync_free_range(dnode_t *dn, uint64_t blkid, uint64_t nblks, dmu_tx_t *tx)
 			return;
 		}
 		ASSERT3U(blkid + nblks, <=, dn->dn_phys->dn_nblkptr);
-		free_blocks(dn, bp + blkid, nblks, tx);
+		(void) free_blocks(dn, bp + blkid, nblks, tx);
 		if (trunc) {
 			uint64_t off = (dn->dn_phys->dn_maxblkid + 1) *
 			    (dn->dn_phys->dn_datablkszsec << SPA_MINBLOCKSHIFT);
 			dn->dn_phys->dn_maxblkid = (blkid ? blkid - 1 : 0);
 			ASSERT(off < dn->dn_phys->dn_maxblkid ||
 			    dn->dn_phys->dn_maxblkid == 0 ||
-			    dnode_next_offset(dn, FALSE, &off,
-			    1, 1, 0) != 0);
+			    dnode_next_offset(dn, 0, &off, 1, 1, 0) != 0);
 		}
 		return;
 	}
@@ -331,9 +342,9 @@ dnode_sync_free_range(dnode_t *dn, uint64_t blkid, uint64_t nblks, dmu_tx_t *tx)
 		ASSERT3U(err, ==, 0);
 		rw_exit(&dn->dn_struct_rwlock);
 
-		if (free_children(db, blkid, nblks, trunc, tx)) {
+		if (free_children(db, blkid, nblks, trunc, tx) == ALL) {
 			ASSERT3P(db->db_blkptr, ==, bp);
-			free_blocks(dn, bp, 1, tx);
+			(void) free_blocks(dn, bp, 1, tx);
 		}
 		dbuf_rele(db, FTAG);
 	}
@@ -343,15 +354,15 @@ dnode_sync_free_range(dnode_t *dn, uint64_t blkid, uint64_t nblks, dmu_tx_t *tx)
 		dn->dn_phys->dn_maxblkid = (blkid ? blkid - 1 : 0);
 		ASSERT(off < dn->dn_phys->dn_maxblkid ||
 		    dn->dn_phys->dn_maxblkid == 0 ||
-		    dnode_next_offset(dn, FALSE, &off, 1, 1, 0) != 0);
+		    dnode_next_offset(dn, 0, &off, 1, 1, 0) != 0);
 	}
 }
 
 /*
  * Try to kick all the dnodes dbufs out of the cache...
  */
-int
-dnode_evict_dbufs(dnode_t *dn, int try)
+void
+dnode_evict_dbufs(dnode_t *dn)
 {
 	int progress;
 	int pass = 0;
@@ -367,6 +378,7 @@ dnode_evict_dbufs(dnode_t *dn, int try)
 		for (; db != &marker; db = list_head(&dn->dn_dbufs)) {
 			list_remove(&dn->dn_dbufs, db);
 			list_insert_tail(&dn->dn_dbufs, db);
+			ASSERT3P(db->db_dnode, ==, dn);
 
 			mutex_enter(&db->db_mtx);
 			if (db->db_state == DB_EVICTING) {
@@ -375,7 +387,6 @@ dnode_evict_dbufs(dnode_t *dn, int try)
 				mutex_exit(&db->db_mtx);
 			} else if (refcount_is_zero(&db->db_holds)) {
 				progress = TRUE;
-				ASSERT(!arc_released(db->db_buf));
 				dbuf_clear(db); /* exits db_mtx for us */
 			} else {
 				mutex_exit(&db->db_mtx);
@@ -397,21 +408,6 @@ dnode_evict_dbufs(dnode_t *dn, int try)
 		ASSERT(pass < 100); /* sanity check */
 	} while (progress);
 
-	/*
-	 * This function works fine even if it can't evict everything.
-	 * If were only asked to try to evict everything then
-	 * return an error if we can't. Otherwise panic as the caller
-	 * expects total eviction.
-	 */
-	if (list_head(&dn->dn_dbufs) != NULL) {
-		if (try) {
-			return (1);
-		} else {
-			panic("dangling dbufs (dn=%p, dbuf=%p)\n",
-			    dn, list_head(&dn->dn_dbufs));
-		}
-	}
-
 	rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
 	if (dn->dn_bonus && refcount_is_zero(&dn->dn_bonus->db_holds)) {
 		mutex_enter(&dn->dn_bonus->db_mtx);
@@ -419,7 +415,6 @@ dnode_evict_dbufs(dnode_t *dn, int try)
 		dn->dn_bonus = NULL;
 	}
 	rw_exit(&dn->dn_struct_rwlock);
-	return (0);
 }
 
 static void
@@ -460,8 +455,15 @@ dnode_sync_free(dnode_t *dn, dmu_tx_t *tx)
 
 	ASSERT(dmu_tx_is_syncing(tx));
 
+	/*
+	 * Our contents should have been freed in dnode_sync() by the
+	 * free range record inserted by the caller of dnode_free().
+	 */
+	ASSERT3U(DN_USED_BYTES(dn->dn_phys), ==, 0);
+	ASSERT(BP_IS_HOLE(dn->dn_phys->dn_blkptr));
+
 	dnode_undirty_dbufs(&dn->dn_dirty_records[txgoff]);
-	(void) dnode_evict_dbufs(dn, 0);
+	dnode_evict_dbufs(dn);
 	ASSERT3P(list_head(&dn->dn_dbufs), ==, NULL);
 
 	/*
@@ -479,10 +481,6 @@ dnode_sync_free(dnode_t *dn, dmu_tx_t *tx)
 	dn->dn_next_indblkshift[txgoff] = 0;
 	dn->dn_next_blksz[txgoff] = 0;
 
-	/* free up all the blocks in the file. */
-	dnode_sync_free_range(dn, 0, dn->dn_phys->dn_maxblkid+1, tx);
-	ASSERT3U(DN_USED_BYTES(dn->dn_phys), ==, 0);
-
 	/* ASSERT(blkptrs are zero); */
 	ASSERT(dn->dn_phys->dn_type != DMU_OT_NONE);
 	ASSERT(dn->dn_type != DMU_OT_NONE);
@@ -496,6 +494,7 @@ dnode_sync_free(dnode_t *dn, dmu_tx_t *tx)
 	dn->dn_type = DMU_OT_NONE;
 	dn->dn_maxblkid = 0;
 	dn->dn_allocated_txg = 0;
+	dn->dn_free_txg = 0;
 	mutex_exit(&dn->dn_mtx);
 
 	ASSERT(dn->dn_object != DMU_META_DNODE_OBJECT);
@@ -558,7 +557,7 @@ dnode_sync(dnode_t *dn, dmu_tx_t *tx)
 		ASSERT(P2PHASE(dn->dn_next_blksz[txgoff],
 		    SPA_MINBLOCKSIZE) == 0);
 		ASSERT(BP_IS_HOLE(&dnp->dn_blkptr[0]) ||
-		    list_head(list) != NULL ||
+		    dn->dn_maxblkid == 0 || list_head(list) != NULL ||
 		    dn->dn_next_blksz[txgoff] >> SPA_MINBLOCKSHIFT ==
 		    dnp->dn_datablkszsec);
 		dnp->dn_datablkszsec =
@@ -566,6 +565,15 @@ dnode_sync(dnode_t *dn, dmu_tx_t *tx)
 		dn->dn_next_blksz[txgoff] = 0;
 	}
 
+	if (dn->dn_next_bonuslen[txgoff]) {
+		if (dn->dn_next_bonuslen[txgoff] == DN_ZERO_BONUSLEN)
+			dnp->dn_bonuslen = 0;
+		else
+			dnp->dn_bonuslen = dn->dn_next_bonuslen[txgoff];
+		ASSERT(dnp->dn_bonuslen <= DN_MAX_BONUSLEN);
+		dn->dn_next_bonuslen[txgoff] = 0;
+	}
+
 	if (dn->dn_next_indblkshift[txgoff]) {
 		ASSERT(dnp->dn_nlevels == 1);
 		dnp->dn_indblkshift = dn->dn_next_indblkshift[txgoff];
@@ -583,20 +591,14 @@ dnode_sync(dnode_t *dn, dmu_tx_t *tx)
 	mutex_exit(&dn->dn_mtx);
 
 	/* process all the "freed" ranges in the file */
-	if (dn->dn_free_txg == 0 || dn->dn_free_txg > tx->tx_txg) {
-		for (rp = avl_last(&dn->dn_ranges[txgoff]); rp != NULL;
-		    rp = AVL_PREV(&dn->dn_ranges[txgoff], rp))
-			dnode_sync_free_range(dn,
-			    rp->fr_blkid, rp->fr_nblks, tx);
+	while (rp = avl_last(&dn->dn_ranges[txgoff])) {
+		dnode_sync_free_range(dn, rp->fr_blkid, rp->fr_nblks, tx);
+		/* grab the mutex so we don't race with dnode_block_freed() */
+		mutex_enter(&dn->dn_mtx);
+		avl_remove(&dn->dn_ranges[txgoff], rp);
+		mutex_exit(&dn->dn_mtx);
+		kmem_free(rp, sizeof (free_range_t));
 	}
-	mutex_enter(&dn->dn_mtx);
-	for (rp = avl_first(&dn->dn_ranges[txgoff]); rp; ) {
-		free_range_t *last = rp;
-		rp = AVL_NEXT(&dn->dn_ranges[txgoff], rp);
-		avl_remove(&dn->dn_ranges[txgoff], last);
-		kmem_free(last, sizeof (free_range_t));
-	}
-	mutex_exit(&dn->dn_mtx);
 
 	if (dn->dn_free_txg > 0 && dn->dn_free_txg <= tx->tx_txg) {
 		dnode_sync_free(dn, tx);
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_dataset.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_dataset.c
index 7d4689f3352a..20d8ec85cc91 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_dataset.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_dataset.c
@@ -19,12 +19,10 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
-#pragma ident	"%Z%%M%	%I%	%E% SMI"
-
 #include <sys/dmu_objset.h>
 #include <sys/dsl_dataset.h>
 #include <sys/dsl_dir.h>
@@ -38,35 +36,44 @@
 #include <sys/unique.h>
 #include <sys/zfs_context.h>
 #include <sys/zfs_ioctl.h>
+#include <sys/spa.h>
+#include <sys/zfs_znode.h>
+#include <sys/sunddi.h>
+
+static char *dsl_reaper = "the grim reaper";
 
 static dsl_checkfunc_t dsl_dataset_destroy_begin_check;
 static dsl_syncfunc_t dsl_dataset_destroy_begin_sync;
 static dsl_checkfunc_t dsl_dataset_rollback_check;
 static dsl_syncfunc_t dsl_dataset_rollback_sync;
-static dsl_checkfunc_t dsl_dataset_destroy_check;
-static dsl_syncfunc_t dsl_dataset_destroy_sync;
+static dsl_syncfunc_t dsl_dataset_set_reservation_sync;
 
 #define	DS_REF_MAX	(1ULL << 62)
 
 #define	DSL_DEADLIST_BLOCKSIZE	SPA_MAXBLOCKSIZE
 
+#define	DSL_DATASET_IS_DESTROYED(ds)	((ds)->ds_owner == dsl_reaper)
+
+
 /*
- * We use weighted reference counts to express the various forms of exclusion
- * between different open modes.  A STANDARD open is 1 point, an EXCLUSIVE open
- * is DS_REF_MAX, and a PRIMARY open is little more than half of an EXCLUSIVE.
- * This makes the exclusion logic simple: the total refcnt for all opens cannot
- * exceed DS_REF_MAX.  For example, EXCLUSIVE opens are exclusive because their
- * weight (DS_REF_MAX) consumes the entire refcnt space.  PRIMARY opens consume
- * just over half of the refcnt space, so there can't be more than one, but it
- * can peacefully coexist with any number of STANDARD opens.
+ * Figure out how much of this delta should be propogated to the dsl_dir
+ * layer.  If there's a refreservation, that space has already been
+ * partially accounted for in our ancestors.
  */
-static uint64_t ds_refcnt_weight[DS_MODE_LEVELS] = {
-	0,			/* DS_MODE_NONE - invalid		*/
-	1,			/* DS_MODE_STANDARD - unlimited number	*/
-	(DS_REF_MAX >> 1) + 1,	/* DS_MODE_PRIMARY - only one of these	*/
-	DS_REF_MAX		/* DS_MODE_EXCLUSIVE - no other opens	*/
-};
+static int64_t
+parent_delta(dsl_dataset_t *ds, int64_t delta)
+{
+	uint64_t old_bytes, new_bytes;
 
+	if (ds->ds_reserved == 0)
+		return (delta);
+
+	old_bytes = MAX(ds->ds_phys->ds_unique_bytes, ds->ds_reserved);
+	new_bytes = MAX(ds->ds_phys->ds_unique_bytes + delta, ds->ds_reserved);
+
+	ASSERT3U(ABS((int64_t)(new_bytes - old_bytes)), <=, ABS(delta));
+	return (new_bytes - old_bytes);
+}
 
 void
 dsl_dataset_block_born(dsl_dataset_t *ds, blkptr_t *bp, dmu_tx_t *tx)
@@ -74,6 +81,7 @@ dsl_dataset_block_born(dsl_dataset_t *ds, blkptr_t *bp, dmu_tx_t *tx)
 	int used = bp_get_dasize(tx->tx_pool->dp_spa, bp);
 	int compressed = BP_GET_PSIZE(bp);
 	int uncompressed = BP_GET_UCSIZE(bp);
+	int64_t delta;
 
 	dprintf_bp(bp, "born, ds=%p\n", ds);
 
@@ -89,23 +97,28 @@ dsl_dataset_block_born(dsl_dataset_t *ds, blkptr_t *bp, dmu_tx_t *tx)
 		 * dsl_dir.
 		 */
 		ASSERT3U(compressed, ==, uncompressed); /* it's all metadata */
-		dsl_dir_diduse_space(tx->tx_pool->dp_mos_dir,
+		dsl_dir_diduse_space(tx->tx_pool->dp_mos_dir, DD_USED_HEAD,
 		    used, compressed, uncompressed, tx);
 		dsl_dir_dirty(tx->tx_pool->dp_mos_dir, tx);
 		return;
 	}
 	dmu_buf_will_dirty(ds->ds_dbuf, tx);
+	mutex_enter(&ds->ds_dir->dd_lock);
 	mutex_enter(&ds->ds_lock);
+	delta = parent_delta(ds, used);
 	ds->ds_phys->ds_used_bytes += used;
 	ds->ds_phys->ds_compressed_bytes += compressed;
 	ds->ds_phys->ds_uncompressed_bytes += uncompressed;
 	ds->ds_phys->ds_unique_bytes += used;
 	mutex_exit(&ds->ds_lock);
-	dsl_dir_diduse_space(ds->ds_dir,
-	    used, compressed, uncompressed, tx);
+	dsl_dir_diduse_space(ds->ds_dir, DD_USED_HEAD, delta,
+	    compressed, uncompressed, tx);
+	dsl_dir_transfer_space(ds->ds_dir, used - delta,
+	    DD_USED_REFRSRV, DD_USED_HEAD, tx);
+	mutex_exit(&ds->ds_dir->dd_lock);
 }
 
-void
+int
 dsl_dataset_block_kill(dsl_dataset_t *ds, blkptr_t *bp, zio_t *pio,
     dmu_tx_t *tx)
 {
@@ -113,10 +126,11 @@ dsl_dataset_block_kill(dsl_dataset_t *ds, blkptr_t *bp, zio_t *pio,
 	int compressed = BP_GET_PSIZE(bp);
 	int uncompressed = BP_GET_UCSIZE(bp);
 
+	ASSERT(pio != NULL);
 	ASSERT(dmu_tx_is_syncing(tx));
 	/* No block pointer => nothing to free */
 	if (BP_IS_HOLE(bp))
-		return;
+		return (0);
 
 	ASSERT(used > 0);
 	if (ds == NULL) {
@@ -125,51 +139,59 @@ dsl_dataset_block_kill(dsl_dataset_t *ds, blkptr_t *bp, zio_t *pio,
 		 * Account for the meta-objset space in its placeholder
 		 * dataset.
 		 */
-		err = arc_free(pio, tx->tx_pool->dp_spa,
-		    tx->tx_txg, bp, NULL, NULL, pio ? ARC_NOWAIT: ARC_WAIT);
+		err = dsl_free(pio, tx->tx_pool,
+		    tx->tx_txg, bp, NULL, NULL, ARC_NOWAIT);
 		ASSERT(err == 0);
 
-		dsl_dir_diduse_space(tx->tx_pool->dp_mos_dir,
+		dsl_dir_diduse_space(tx->tx_pool->dp_mos_dir, DD_USED_HEAD,
 		    -used, -compressed, -uncompressed, tx);
 		dsl_dir_dirty(tx->tx_pool->dp_mos_dir, tx);
-		return;
+		return (used);
 	}
 	ASSERT3P(tx->tx_pool, ==, ds->ds_dir->dd_pool);
 
+	ASSERT(!dsl_dataset_is_snapshot(ds));
 	dmu_buf_will_dirty(ds->ds_dbuf, tx);
 
 	if (bp->blk_birth > ds->ds_phys->ds_prev_snap_txg) {
 		int err;
+		int64_t delta;
 
 		dprintf_bp(bp, "freeing: %s", "");
-		err = arc_free(pio, tx->tx_pool->dp_spa,
-		    tx->tx_txg, bp, NULL, NULL, pio ? ARC_NOWAIT: ARC_WAIT);
+		err = dsl_free(pio, tx->tx_pool,
+		    tx->tx_txg, bp, NULL, NULL, ARC_NOWAIT);
 		ASSERT(err == 0);
 
+		mutex_enter(&ds->ds_dir->dd_lock);
 		mutex_enter(&ds->ds_lock);
-		/* XXX unique_bytes is not accurate for head datasets */
-		/* ASSERT3U(ds->ds_phys->ds_unique_bytes, >=, used); */
+		ASSERT(ds->ds_phys->ds_unique_bytes >= used ||
+		    !DS_UNIQUE_IS_ACCURATE(ds));
+		delta = parent_delta(ds, -used);
 		ds->ds_phys->ds_unique_bytes -= used;
 		mutex_exit(&ds->ds_lock);
-		dsl_dir_diduse_space(ds->ds_dir,
-		    -used, -compressed, -uncompressed, tx);
+		dsl_dir_diduse_space(ds->ds_dir, DD_USED_HEAD,
+		    delta, -compressed, -uncompressed, tx);
+		dsl_dir_transfer_space(ds->ds_dir, -used - delta,
+		    DD_USED_REFRSRV, DD_USED_HEAD, tx);
+		mutex_exit(&ds->ds_dir->dd_lock);
 	} else {
 		dprintf_bp(bp, "putting on dead list: %s", "");
 		VERIFY(0 == bplist_enqueue(&ds->ds_deadlist, bp, tx));
+		ASSERT3U(ds->ds_prev->ds_object, ==,
+		    ds->ds_phys->ds_prev_snap_obj);
+		ASSERT(ds->ds_prev->ds_phys->ds_num_children > 0);
 		/* if (bp->blk_birth > prev prev snap txg) prev unique += bs */
-		if (ds->ds_phys->ds_prev_snap_obj != 0) {
-			ASSERT3U(ds->ds_prev->ds_object, ==,
-			    ds->ds_phys->ds_prev_snap_obj);
-			ASSERT(ds->ds_prev->ds_phys->ds_num_children > 0);
-			if (ds->ds_prev->ds_phys->ds_next_snap_obj ==
-			    ds->ds_object && bp->blk_birth >
-			    ds->ds_prev->ds_phys->ds_prev_snap_txg) {
-				dmu_buf_will_dirty(ds->ds_prev->ds_dbuf, tx);
-				mutex_enter(&ds->ds_prev->ds_lock);
-				ds->ds_prev->ds_phys->ds_unique_bytes +=
-				    used;
-				mutex_exit(&ds->ds_prev->ds_lock);
-			}
+		if (ds->ds_prev->ds_phys->ds_next_snap_obj ==
+		    ds->ds_object && bp->blk_birth >
+		    ds->ds_prev->ds_phys->ds_prev_snap_txg) {
+			dmu_buf_will_dirty(ds->ds_prev->ds_dbuf, tx);
+			mutex_enter(&ds->ds_prev->ds_lock);
+			ds->ds_prev->ds_phys->ds_unique_bytes += used;
+			mutex_exit(&ds->ds_prev->ds_lock);
+		}
+		if (bp->blk_birth > ds->ds_origin_txg) {
+			dsl_dir_transfer_space(ds->ds_dir, used,
+			    DD_USED_HEAD, DD_USED_SNAP, tx);
 		}
 	}
 	mutex_enter(&ds->ds_lock);
@@ -180,6 +202,8 @@ dsl_dataset_block_kill(dsl_dataset_t *ds, blkptr_t *bp, zio_t *pio,
 	ASSERT3U(ds->ds_phys->ds_uncompressed_bytes, >=, uncompressed);
 	ds->ds_phys->ds_uncompressed_bytes -= uncompressed;
 	mutex_exit(&ds->ds_lock);
+
+	return (used);
 }
 
 uint64_t
@@ -216,32 +240,38 @@ static void
 dsl_dataset_evict(dmu_buf_t *db, void *dsv)
 {
 	dsl_dataset_t *ds = dsv;
-	dsl_pool_t *dp = ds->ds_dir->dd_pool;
 
-	/* open_refcount == DS_REF_MAX when deleting */
-	ASSERT(ds->ds_open_refcount == 0 ||
-	    ds->ds_open_refcount == DS_REF_MAX);
+	ASSERT(ds->ds_owner == NULL || DSL_DATASET_IS_DESTROYED(ds));
 
 	dprintf_ds(ds, "evicting %s\n", "");
 
-	unique_remove(ds->ds_phys->ds_fsid_guid);
+	unique_remove(ds->ds_fsid_guid);
 
 	if (ds->ds_user_ptr != NULL)
 		ds->ds_user_evict_func(ds, ds->ds_user_ptr);
 
 	if (ds->ds_prev) {
-		dsl_dataset_close(ds->ds_prev, DS_MODE_NONE, ds);
+		dsl_dataset_drop_ref(ds->ds_prev, ds);
 		ds->ds_prev = NULL;
 	}
 
 	bplist_close(&ds->ds_deadlist);
-	dsl_dir_close(ds->ds_dir, ds);
+	if (ds->ds_dir)
+		dsl_dir_close(ds->ds_dir, ds);
 
-	if (list_link_active(&ds->ds_synced_link))
-		list_remove(&dp->dp_synced_objsets, ds);
+	ASSERT(!list_link_active(&ds->ds_synced_link));
 
+	if (mutex_owned(&ds->ds_lock))
+		mutex_exit(&ds->ds_lock);
 	mutex_destroy(&ds->ds_lock);
+	if (mutex_owned(&ds->ds_opening_lock))
+		mutex_exit(&ds->ds_opening_lock);
+	mutex_destroy(&ds->ds_opening_lock);
+	if (mutex_owned(&ds->ds_deadlist.bpl_lock))
+		mutex_exit(&ds->ds_deadlist.bpl_lock);
 	mutex_destroy(&ds->ds_deadlist.bpl_lock);
+	rw_destroy(&ds->ds_rwlock);
+	cv_destroy(&ds->ds_exclusive_cv);
 
 	kmem_free(ds, sizeof (dsl_dataset_t));
 }
@@ -266,16 +296,54 @@ dsl_dataset_get_snapname(dsl_dataset_t *ds)
 		return (err);
 	headphys = headdbuf->db_data;
 	err = zap_value_search(dp->dp_meta_objset,
-	    headphys->ds_snapnames_zapobj, ds->ds_object, ds->ds_snapname);
+	    headphys->ds_snapnames_zapobj, ds->ds_object, 0, ds->ds_snapname);
 	dmu_buf_rele(headdbuf, FTAG);
 	return (err);
 }
 
-int
-dsl_dataset_open_obj(dsl_pool_t *dp, uint64_t dsobj, const char *snapname,
-    int mode, void *tag, dsl_dataset_t **dsp)
+static int
+dsl_dataset_snap_lookup(dsl_dataset_t *ds, const char *name, uint64_t *value)
+{
+	objset_t *mos = ds->ds_dir->dd_pool->dp_meta_objset;
+	uint64_t snapobj = ds->ds_phys->ds_snapnames_zapobj;
+	matchtype_t mt;
+	int err;
+
+	if (ds->ds_phys->ds_flags & DS_FLAG_CI_DATASET)
+		mt = MT_FIRST;
+	else
+		mt = MT_EXACT;
+
+	err = zap_lookup_norm(mos, snapobj, name, 8, 1,
+	    value, mt, NULL, 0, NULL);
+	if (err == ENOTSUP && mt == MT_FIRST)
+		err = zap_lookup(mos, snapobj, name, 8, 1, value);
+	return (err);
+}
+
+static int
+dsl_dataset_snap_remove(dsl_dataset_t *ds, char *name, dmu_tx_t *tx)
+{
+	objset_t *mos = ds->ds_dir->dd_pool->dp_meta_objset;
+	uint64_t snapobj = ds->ds_phys->ds_snapnames_zapobj;
+	matchtype_t mt;
+	int err;
+
+	if (ds->ds_phys->ds_flags & DS_FLAG_CI_DATASET)
+		mt = MT_FIRST;
+	else
+		mt = MT_EXACT;
+
+	err = zap_remove_norm(mos, snapobj, name, mt, tx);
+	if (err == ENOTSUP && mt == MT_FIRST)
+		err = zap_remove(mos, snapobj, name, tx);
+	return (err);
+}
+
+static int
+dsl_dataset_get_ref(dsl_pool_t *dp, uint64_t dsobj, void *tag,
+    dsl_dataset_t **dsp)
 {
-	uint64_t weight = ds_refcnt_weight[DS_MODE_LEVEL(mode)];
 	objset_t *mos = dp->dp_meta_objset;
 	dmu_buf_t *dbuf;
 	dsl_dataset_t *ds;
@@ -297,8 +365,11 @@ dsl_dataset_open_obj(dsl_pool_t *dp, uint64_t dsobj, const char *snapname,
 		ds->ds_phys = dbuf->db_data;
 
 		mutex_init(&ds->ds_lock, NULL, MUTEX_DEFAULT, NULL);
+		mutex_init(&ds->ds_opening_lock, NULL, MUTEX_DEFAULT, NULL);
 		mutex_init(&ds->ds_deadlist.bpl_lock, NULL, MUTEX_DEFAULT,
 		    NULL);
+		rw_init(&ds->ds_rwlock, 0, 0, 0);
+		cv_init(&ds->ds_exclusive_cv, NULL, CV_DEFAULT, NULL);
 
 		err = bplist_open(&ds->ds_deadlist,
 		    mos, ds->ds_phys->ds_deadlist_obj);
@@ -312,42 +383,65 @@ dsl_dataset_open_obj(dsl_pool_t *dp, uint64_t dsobj, const char *snapname,
 			 * just opened it.
 			 */
 			mutex_destroy(&ds->ds_lock);
+			mutex_destroy(&ds->ds_opening_lock);
 			mutex_destroy(&ds->ds_deadlist.bpl_lock);
+			rw_destroy(&ds->ds_rwlock);
+			cv_destroy(&ds->ds_exclusive_cv);
 			kmem_free(ds, sizeof (dsl_dataset_t));
 			dmu_buf_rele(dbuf, tag);
 			return (err);
 		}
 
-		if (ds->ds_dir->dd_phys->dd_head_dataset_obj == dsobj) {
+		if (!dsl_dataset_is_snapshot(ds)) {
 			ds->ds_snapname[0] = '\0';
 			if (ds->ds_phys->ds_prev_snap_obj) {
-				err = dsl_dataset_open_obj(dp,
-				    ds->ds_phys->ds_prev_snap_obj, NULL,
-				    DS_MODE_NONE, ds, &ds->ds_prev);
+				err = dsl_dataset_get_ref(dp,
+				    ds->ds_phys->ds_prev_snap_obj,
+				    ds, &ds->ds_prev);
 			}
-		} else {
-			if (snapname) {
-#ifdef ZFS_DEBUG
-				dsl_dataset_phys_t *headphys;
-				dmu_buf_t *headdbuf;
-				err = dmu_bonus_hold(mos,
-				    ds->ds_dir->dd_phys->dd_head_dataset_obj,
-				    FTAG, &headdbuf);
+
+			if (err == 0 && dsl_dir_is_clone(ds->ds_dir)) {
+				dsl_dataset_t *origin;
+
+				err = dsl_dataset_hold_obj(dp,
+				    ds->ds_dir->dd_phys->dd_origin_obj,
+				    FTAG, &origin);
 				if (err == 0) {
-					headphys = headdbuf->db_data;
-					uint64_t foundobj;
-					err = zap_lookup(dp->dp_meta_objset,
-					    headphys->ds_snapnames_zapobj,
-					    snapname, sizeof (foundobj), 1,
-					    &foundobj);
-					ASSERT3U(foundobj, ==, dsobj);
-					dmu_buf_rele(headdbuf, FTAG);
+					ds->ds_origin_txg =
+					    origin->ds_phys->ds_creation_txg;
+					dsl_dataset_rele(origin, FTAG);
 				}
-#endif
-				(void) strcat(ds->ds_snapname, snapname);
-			} else if (zfs_flags & ZFS_DEBUG_SNAPNAMES) {
-				err = dsl_dataset_get_snapname(ds);
 			}
+		} else if (zfs_flags & ZFS_DEBUG_SNAPNAMES) {
+			err = dsl_dataset_get_snapname(ds);
+		}
+
+		if (err == 0 && !dsl_dataset_is_snapshot(ds)) {
+			/*
+			 * In sync context, we're called with either no lock
+			 * or with the write lock.  If we're not syncing,
+			 * we're always called with the read lock held.
+			 */
+			boolean_t need_lock =
+			    !RW_WRITE_HELD(&dp->dp_config_rwlock) &&
+			    dsl_pool_sync_context(dp);
+
+			if (need_lock)
+				rw_enter(&dp->dp_config_rwlock, RW_READER);
+
+			err = dsl_prop_get_ds(ds,
+			    "refreservation", sizeof (uint64_t), 1,
+			    &ds->ds_reserved, NULL);
+			if (err == 0) {
+				err = dsl_prop_get_ds(ds,
+				    "refquota", sizeof (uint64_t), 1,
+				    &ds->ds_quota, NULL);
+			}
+
+			if (need_lock)
+				rw_exit(&dp->dp_config_rwlock);
+		} else {
+			ds->ds_reserved = ds->ds_quota = 0;
 		}
 
 		if (err == 0) {
@@ -356,13 +450,14 @@ dsl_dataset_open_obj(dsl_pool_t *dp, uint64_t dsobj, const char *snapname,
 		}
 		if (err || winner) {
 			bplist_close(&ds->ds_deadlist);
-			if (ds->ds_prev) {
-				dsl_dataset_close(ds->ds_prev,
-				    DS_MODE_NONE, ds);
-			}
+			if (ds->ds_prev)
+				dsl_dataset_drop_ref(ds->ds_prev, ds);
 			dsl_dir_close(ds->ds_dir, ds);
 			mutex_destroy(&ds->ds_lock);
+			mutex_destroy(&ds->ds_opening_lock);
 			mutex_destroy(&ds->ds_deadlist.bpl_lock);
+			rw_destroy(&ds->ds_rwlock);
+			cv_destroy(&ds->ds_exclusive_cv);
 			kmem_free(ds, sizeof (dsl_dataset_t));
 			if (err) {
 				dmu_buf_rele(dbuf, tag);
@@ -370,101 +465,175 @@ dsl_dataset_open_obj(dsl_pool_t *dp, uint64_t dsobj, const char *snapname,
 			}
 			ds = winner;
 		} else {
-			uint64_t new =
+			ds->ds_fsid_guid =
 			    unique_insert(ds->ds_phys->ds_fsid_guid);
-			if (new != ds->ds_phys->ds_fsid_guid) {
-				/* XXX it won't necessarily be synced... */
-				ds->ds_phys->ds_fsid_guid = new;
-			}
 		}
 	}
 	ASSERT3P(ds->ds_dbuf, ==, dbuf);
 	ASSERT3P(ds->ds_phys, ==, dbuf->db_data);
-
+	ASSERT(ds->ds_phys->ds_prev_snap_obj != 0 ||
+	    spa_version(dp->dp_spa) < SPA_VERSION_ORIGIN ||
+	    dp->dp_origin_snap == NULL || ds == dp->dp_origin_snap);
 	mutex_enter(&ds->ds_lock);
-	if ((DS_MODE_LEVEL(mode) == DS_MODE_PRIMARY &&
-	    (ds->ds_phys->ds_flags & DS_FLAG_INCONSISTENT) &&
-	    !DS_MODE_IS_INCONSISTENT(mode)) ||
-	    (ds->ds_open_refcount + weight > DS_REF_MAX)) {
+	if (!dsl_pool_sync_context(dp) && DSL_DATASET_IS_DESTROYED(ds)) {
 		mutex_exit(&ds->ds_lock);
-		dsl_dataset_close(ds, DS_MODE_NONE, tag);
-		return (EBUSY);
+		dmu_buf_rele(ds->ds_dbuf, tag);
+		return (ENOENT);
 	}
-	ds->ds_open_refcount += weight;
 	mutex_exit(&ds->ds_lock);
-
 	*dsp = ds;
 	return (0);
 }
 
+static int
+dsl_dataset_hold_ref(dsl_dataset_t *ds, void *tag)
+{
+	dsl_pool_t *dp = ds->ds_dir->dd_pool;
+
+	/*
+	 * In syncing context we don't want the rwlock lock: there
+	 * may be an existing writer waiting for sync phase to
+	 * finish.  We don't need to worry about such writers, since
+	 * sync phase is single-threaded, so the writer can't be
+	 * doing anything while we are active.
+	 */
+	if (dsl_pool_sync_context(dp)) {
+		ASSERT(!DSL_DATASET_IS_DESTROYED(ds));
+		return (0);
+	}
+
+	/*
+	 * Normal users will hold the ds_rwlock as a READER until they
+	 * are finished (i.e., call dsl_dataset_rele()).  "Owners" will
+	 * drop their READER lock after they set the ds_owner field.
+	 *
+	 * If the dataset is being destroyed, the destroy thread will
+	 * obtain a WRITER lock for exclusive access after it's done its
+	 * open-context work and then change the ds_owner to
+	 * dsl_reaper once destruction is assured.  So threads
+	 * may block here temporarily, until the "destructability" of
+	 * the dataset is determined.
+	 */
+	ASSERT(!RW_WRITE_HELD(&dp->dp_config_rwlock));
+	mutex_enter(&ds->ds_lock);
+	while (!rw_tryenter(&ds->ds_rwlock, RW_READER)) {
+		rw_exit(&dp->dp_config_rwlock);
+		cv_wait(&ds->ds_exclusive_cv, &ds->ds_lock);
+		if (DSL_DATASET_IS_DESTROYED(ds)) {
+			mutex_exit(&ds->ds_lock);
+			dsl_dataset_drop_ref(ds, tag);
+			rw_enter(&dp->dp_config_rwlock, RW_READER);
+			return (ENOENT);
+		}
+		rw_enter(&dp->dp_config_rwlock, RW_READER);
+	}
+	mutex_exit(&ds->ds_lock);
+	return (0);
+}
+
+int
+dsl_dataset_hold_obj(dsl_pool_t *dp, uint64_t dsobj, void *tag,
+    dsl_dataset_t **dsp)
+{
+	int err = dsl_dataset_get_ref(dp, dsobj, tag, dsp);
+
+	if (err)
+		return (err);
+	return (dsl_dataset_hold_ref(*dsp, tag));
+}
+
 int
-dsl_dataset_open_spa(spa_t *spa, const char *name, int mode,
-    void *tag, dsl_dataset_t **dsp)
+dsl_dataset_own_obj(dsl_pool_t *dp, uint64_t dsobj, int flags, void *owner,
+    dsl_dataset_t **dsp)
+{
+	int err = dsl_dataset_hold_obj(dp, dsobj, owner, dsp);
+
+	ASSERT(DS_MODE_TYPE(flags) != DS_MODE_USER);
+
+	if (err)
+		return (err);
+	if (!dsl_dataset_tryown(*dsp, DS_MODE_IS_INCONSISTENT(flags), owner)) {
+		dsl_dataset_rele(*dsp, owner);
+		return (EBUSY);
+	}
+	return (0);
+}
+
+int
+dsl_dataset_hold(const char *name, void *tag, dsl_dataset_t **dsp)
 {
 	dsl_dir_t *dd;
 	dsl_pool_t *dp;
-	const char *tail;
+	const char *snapname;
 	uint64_t obj;
-	dsl_dataset_t *ds = NULL;
 	int err = 0;
 
-	err = dsl_dir_open_spa(spa, name, FTAG, &dd, &tail);
+	err = dsl_dir_open_spa(NULL, name, FTAG, &dd, &snapname);
 	if (err)
 		return (err);
 
 	dp = dd->dd_pool;
 	obj = dd->dd_phys->dd_head_dataset_obj;
 	rw_enter(&dp->dp_config_rwlock, RW_READER);
-	if (obj == 0) {
-		/* A dataset with no associated objset */
+	if (obj)
+		err = dsl_dataset_get_ref(dp, obj, tag, dsp);
+	else
 		err = ENOENT;
+	if (err)
 		goto out;
-	}
 
-	if (tail != NULL) {
-		objset_t *mos = dp->dp_meta_objset;
+	err = dsl_dataset_hold_ref(*dsp, tag);
 
-		err = dsl_dataset_open_obj(dp, obj, NULL,
-		    DS_MODE_NONE, tag, &ds);
-		if (err)
-			goto out;
-		obj = ds->ds_phys->ds_snapnames_zapobj;
-		dsl_dataset_close(ds, DS_MODE_NONE, tag);
-		ds = NULL;
+	/* we may be looking for a snapshot */
+	if (err == 0 && snapname != NULL) {
+		dsl_dataset_t *ds = NULL;
 
-		if (tail[0] != '@') {
+		if (*snapname++ != '@') {
+			dsl_dataset_rele(*dsp, tag);
 			err = ENOENT;
 			goto out;
 		}
-		tail++;
 
-		/* Look for a snapshot */
-		if (!DS_MODE_IS_READONLY(mode)) {
-			err = EROFS;
-			goto out;
+		dprintf("looking for snapshot '%s'\n", snapname);
+		err = dsl_dataset_snap_lookup(*dsp, snapname, &obj);
+		if (err == 0)
+			err = dsl_dataset_get_ref(dp, obj, tag, &ds);
+		dsl_dataset_rele(*dsp, tag);
+
+		ASSERT3U((err == 0), ==, (ds != NULL));
+
+		if (ds) {
+			mutex_enter(&ds->ds_lock);
+			if (ds->ds_snapname[0] == 0)
+				(void) strlcpy(ds->ds_snapname, snapname,
+				    sizeof (ds->ds_snapname));
+			mutex_exit(&ds->ds_lock);
+			err = dsl_dataset_hold_ref(ds, tag);
+			*dsp = err ? NULL : ds;
 		}
-		dprintf("looking for snapshot '%s'\n", tail);
-		err = zap_lookup(mos, obj, tail, 8, 1, &obj);
-		if (err)
-			goto out;
 	}
-	err = dsl_dataset_open_obj(dp, obj, tail, mode, tag, &ds);
-
 out:
 	rw_exit(&dp->dp_config_rwlock);
 	dsl_dir_close(dd, FTAG);
-
-	ASSERT3U((err == 0), ==, (ds != NULL));
-	/* ASSERT(ds == NULL || strcmp(name, ds->ds_name) == 0); */
-
-	*dsp = ds;
 	return (err);
 }
 
 int
-dsl_dataset_open(const char *name, int mode, void *tag, dsl_dataset_t **dsp)
+dsl_dataset_own(const char *name, int flags, void *owner, dsl_dataset_t **dsp)
 {
-	return (dsl_dataset_open_spa(NULL, name, mode, tag, dsp));
+	int err = dsl_dataset_hold(name, owner, dsp);
+	if (err)
+		return (err);
+	if ((*dsp)->ds_phys->ds_num_children > 0 &&
+	    !DS_MODE_IS_READONLY(flags)) {
+		dsl_dataset_rele(*dsp, owner);
+		return (EROFS);
+	}
+	if (!dsl_dataset_tryown(*dsp, DS_MODE_IS_INCONSISTENT(flags), owner)) {
+		dsl_dataset_rele(*dsp, owner);
+		return (EBUSY);
+	}
+	return (0);
 }
 
 void
@@ -477,11 +646,11 @@ dsl_dataset_name(dsl_dataset_t *ds, char *name)
 		VERIFY(0 == dsl_dataset_get_snapname(ds));
 		if (ds->ds_snapname[0]) {
 			(void) strcat(name, "@");
+			/*
+			 * We use a "recursive" mutex so that we
+			 * can call dprintf_ds() with ds_lock held.
+			 */
 			if (!MUTEX_HELD(&ds->ds_lock)) {
-				/*
-				 * We use a "recursive" mutex so that we
-				 * can call dprintf_ds() with ds_lock held.
-				 */
 				mutex_enter(&ds->ds_lock);
 				(void) strcat(name, ds->ds_snapname);
 				mutex_exit(&ds->ds_lock);
@@ -505,7 +674,6 @@ dsl_dataset_namelen(dsl_dataset_t *ds)
 		if (ds->ds_snapname[0]) {
 			++result;	/* adding one for the @-sign */
 			if (!MUTEX_HELD(&ds->ds_lock)) {
-				/* see dsl_datset_name */
 				mutex_enter(&ds->ds_lock);
 				result += strlen(ds->ds_snapname);
 				mutex_exit(&ds->ds_lock);
@@ -519,119 +687,160 @@ dsl_dataset_namelen(dsl_dataset_t *ds)
 }
 
 void
-dsl_dataset_close(dsl_dataset_t *ds, int mode, void *tag)
+dsl_dataset_drop_ref(dsl_dataset_t *ds, void *tag)
 {
-	uint64_t weight = ds_refcnt_weight[DS_MODE_LEVEL(mode)];
+	dmu_buf_rele(ds->ds_dbuf, tag);
+}
+
+void
+dsl_dataset_rele(dsl_dataset_t *ds, void *tag)
+{
+	if (!dsl_pool_sync_context(ds->ds_dir->dd_pool)) {
+		rw_exit(&ds->ds_rwlock);
+	}
+	dsl_dataset_drop_ref(ds, tag);
+}
+
+void
+dsl_dataset_disown(dsl_dataset_t *ds, void *owner)
+{
+	ASSERT((ds->ds_owner == owner && ds->ds_dbuf) ||
+	    (DSL_DATASET_IS_DESTROYED(ds) && ds->ds_dbuf == NULL));
+
 	mutex_enter(&ds->ds_lock);
-	ASSERT3U(ds->ds_open_refcount, >=, weight);
-	ds->ds_open_refcount -= weight;
-	dprintf_ds(ds, "closing mode %u refcount now 0x%llx\n",
-	    mode, ds->ds_open_refcount);
+	ds->ds_owner = NULL;
+	if (RW_WRITE_HELD(&ds->ds_rwlock)) {
+		rw_exit(&ds->ds_rwlock);
+		cv_broadcast(&ds->ds_exclusive_cv);
+	}
 	mutex_exit(&ds->ds_lock);
+	if (ds->ds_dbuf)
+		dsl_dataset_drop_ref(ds, owner);
+	else
+		dsl_dataset_evict(ds->ds_dbuf, ds);
+}
 
-	dmu_buf_rele(ds->ds_dbuf, tag);
+boolean_t
+dsl_dataset_tryown(dsl_dataset_t *ds, boolean_t inconsistentok, void *owner)
+{
+	boolean_t gotit = FALSE;
+
+	mutex_enter(&ds->ds_lock);
+	if (ds->ds_owner == NULL &&
+	    (!DS_IS_INCONSISTENT(ds) || inconsistentok)) {
+		ds->ds_owner = owner;
+		if (!dsl_pool_sync_context(ds->ds_dir->dd_pool))
+			rw_exit(&ds->ds_rwlock);
+		gotit = TRUE;
+	}
+	mutex_exit(&ds->ds_lock);
+	return (gotit);
 }
 
 void
-dsl_dataset_create_root(dsl_pool_t *dp, uint64_t *ddobjp, dmu_tx_t *tx)
+dsl_dataset_make_exclusive(dsl_dataset_t *ds, void *owner)
 {
-	objset_t *mos = dp->dp_meta_objset;
+	ASSERT3P(owner, ==, ds->ds_owner);
+	if (!RW_WRITE_HELD(&ds->ds_rwlock))
+		rw_enter(&ds->ds_rwlock, RW_WRITER);
+}
+
+uint64_t
+dsl_dataset_create_sync_dd(dsl_dir_t *dd, dsl_dataset_t *origin,
+    uint64_t flags, dmu_tx_t *tx)
+{
+	dsl_pool_t *dp = dd->dd_pool;
 	dmu_buf_t *dbuf;
 	dsl_dataset_phys_t *dsphys;
-	dsl_dataset_t *ds;
 	uint64_t dsobj;
-	dsl_dir_t *dd;
+	objset_t *mos = dp->dp_meta_objset;
 
-	dsl_dir_create_root(mos, ddobjp, tx);
-	VERIFY(0 == dsl_dir_open_obj(dp, *ddobjp, NULL, FTAG, &dd));
+	if (origin == NULL)
+		origin = dp->dp_origin_snap;
+
+	ASSERT(origin == NULL || origin->ds_dir->dd_pool == dp);
+	ASSERT(origin == NULL || origin->ds_phys->ds_num_children > 0);
+	ASSERT(dmu_tx_is_syncing(tx));
+	ASSERT(dd->dd_phys->dd_head_dataset_obj == 0);
 
 	dsobj = dmu_object_alloc(mos, DMU_OT_DSL_DATASET, 0,
 	    DMU_OT_DSL_DATASET, sizeof (dsl_dataset_phys_t), tx);
 	VERIFY(0 == dmu_bonus_hold(mos, dsobj, FTAG, &dbuf));
 	dmu_buf_will_dirty(dbuf, tx);
 	dsphys = dbuf->db_data;
+	bzero(dsphys, sizeof (dsl_dataset_phys_t));
 	dsphys->ds_dir_obj = dd->dd_object;
+	dsphys->ds_flags = flags;
 	dsphys->ds_fsid_guid = unique_create();
-	unique_remove(dsphys->ds_fsid_guid); /* it isn't open yet */
 	(void) random_get_pseudo_bytes((void*)&dsphys->ds_guid,
 	    sizeof (dsphys->ds_guid));
 	dsphys->ds_snapnames_zapobj =
-	    zap_create(mos, DMU_OT_DSL_DS_SNAP_MAP, DMU_OT_NONE, 0, tx);
+	    zap_create_norm(mos, U8_TEXTPREP_TOUPPER, DMU_OT_DSL_DS_SNAP_MAP,
+	    DMU_OT_NONE, 0, tx);
 	dsphys->ds_creation_time = gethrestime_sec();
-	dsphys->ds_creation_txg = tx->tx_txg;
+	dsphys->ds_creation_txg = tx->tx_txg == TXG_INITIAL ? 1 : tx->tx_txg;
 	dsphys->ds_deadlist_obj =
 	    bplist_create(mos, DSL_DEADLIST_BLOCKSIZE, tx);
+
+	if (origin) {
+		dsphys->ds_prev_snap_obj = origin->ds_object;
+		dsphys->ds_prev_snap_txg =
+		    origin->ds_phys->ds_creation_txg;
+		dsphys->ds_used_bytes =
+		    origin->ds_phys->ds_used_bytes;
+		dsphys->ds_compressed_bytes =
+		    origin->ds_phys->ds_compressed_bytes;
+		dsphys->ds_uncompressed_bytes =
+		    origin->ds_phys->ds_uncompressed_bytes;
+		dsphys->ds_bp = origin->ds_phys->ds_bp;
+		dsphys->ds_flags |= origin->ds_phys->ds_flags;
+
+		dmu_buf_will_dirty(origin->ds_dbuf, tx);
+		origin->ds_phys->ds_num_children++;
+
+		if (spa_version(dp->dp_spa) >= SPA_VERSION_NEXT_CLONES) {
+			if (origin->ds_phys->ds_next_clones_obj == 0) {
+				origin->ds_phys->ds_next_clones_obj =
+				    zap_create(mos,
+				    DMU_OT_NEXT_CLONES, DMU_OT_NONE, 0, tx);
+			}
+			VERIFY(0 == zap_add_int(mos,
+			    origin->ds_phys->ds_next_clones_obj,
+			    dsobj, tx));
+		}
+
+		dmu_buf_will_dirty(dd->dd_dbuf, tx);
+		dd->dd_phys->dd_origin_obj = origin->ds_object;
+	}
+
+	if (spa_version(dp->dp_spa) >= SPA_VERSION_UNIQUE_ACCURATE)
+		dsphys->ds_flags |= DS_FLAG_UNIQUE_ACCURATE;
+
 	dmu_buf_rele(dbuf, FTAG);
 
 	dmu_buf_will_dirty(dd->dd_dbuf, tx);
 	dd->dd_phys->dd_head_dataset_obj = dsobj;
-	dsl_dir_close(dd, FTAG);
 
-	VERIFY(0 ==
-	    dsl_dataset_open_obj(dp, dsobj, NULL, DS_MODE_NONE, FTAG, &ds));
-	(void) dmu_objset_create_impl(dp->dp_spa, ds,
-	    &ds->ds_phys->ds_bp, DMU_OST_ZFS, tx);
-	dsl_dataset_close(ds, DS_MODE_NONE, FTAG);
+	return (dsobj);
 }
 
 uint64_t
-dsl_dataset_create_sync(dsl_dir_t *pdd,
-    const char *lastname, dsl_dataset_t *clone_parent, dmu_tx_t *tx)
+dsl_dataset_create_sync(dsl_dir_t *pdd, const char *lastname,
+    dsl_dataset_t *origin, uint64_t flags, cred_t *cr, dmu_tx_t *tx)
 {
 	dsl_pool_t *dp = pdd->dd_pool;
-	dmu_buf_t *dbuf;
-	dsl_dataset_phys_t *dsphys;
 	uint64_t dsobj, ddobj;
-	objset_t *mos = dp->dp_meta_objset;
 	dsl_dir_t *dd;
 
-	ASSERT(clone_parent == NULL || clone_parent->ds_dir->dd_pool == dp);
-	ASSERT(clone_parent == NULL ||
-	    clone_parent->ds_phys->ds_num_children > 0);
 	ASSERT(lastname[0] != '@');
-	ASSERT(dmu_tx_is_syncing(tx));
 
-	ddobj = dsl_dir_create_sync(pdd, lastname, tx);
+	ddobj = dsl_dir_create_sync(dp, pdd, lastname, tx);
 	VERIFY(0 == dsl_dir_open_obj(dp, ddobj, lastname, FTAG, &dd));
 
-	dsobj = dmu_object_alloc(mos, DMU_OT_DSL_DATASET, 0,
-	    DMU_OT_DSL_DATASET, sizeof (dsl_dataset_phys_t), tx);
-	VERIFY(0 == dmu_bonus_hold(mos, dsobj, FTAG, &dbuf));
-	dmu_buf_will_dirty(dbuf, tx);
-	dsphys = dbuf->db_data;
-	dsphys->ds_dir_obj = dd->dd_object;
-	dsphys->ds_fsid_guid = unique_create();
-	unique_remove(dsphys->ds_fsid_guid); /* it isn't open yet */
-	(void) random_get_pseudo_bytes((void*)&dsphys->ds_guid,
-	    sizeof (dsphys->ds_guid));
-	dsphys->ds_snapnames_zapobj =
-	    zap_create(mos, DMU_OT_DSL_DS_SNAP_MAP, DMU_OT_NONE, 0, tx);
-	dsphys->ds_creation_time = gethrestime_sec();
-	dsphys->ds_creation_txg = tx->tx_txg;
-	dsphys->ds_deadlist_obj =
-	    bplist_create(mos, DSL_DEADLIST_BLOCKSIZE, tx);
-	if (clone_parent) {
-		dsphys->ds_prev_snap_obj = clone_parent->ds_object;
-		dsphys->ds_prev_snap_txg =
-		    clone_parent->ds_phys->ds_creation_txg;
-		dsphys->ds_used_bytes =
-		    clone_parent->ds_phys->ds_used_bytes;
-		dsphys->ds_compressed_bytes =
-		    clone_parent->ds_phys->ds_compressed_bytes;
-		dsphys->ds_uncompressed_bytes =
-		    clone_parent->ds_phys->ds_uncompressed_bytes;
-		dsphys->ds_bp = clone_parent->ds_phys->ds_bp;
+	dsobj = dsl_dataset_create_sync_dd(dd, origin, flags, tx);
 
-		dmu_buf_will_dirty(clone_parent->ds_dbuf, tx);
-		clone_parent->ds_phys->ds_num_children++;
+	dsl_deleg_set_create_perms(dd, tx, cr);
 
-		dmu_buf_will_dirty(dd->dd_dbuf, tx);
-		dd->dd_phys->dd_clone_parent_obj = clone_parent->ds_object;
-	}
-	dmu_buf_rele(dbuf, FTAG);
-
-	dmu_buf_will_dirty(dd->dd_dbuf, tx);
-	dd->dd_phys->dd_head_dataset_obj = dsobj;
 	dsl_dir_close(dd, FTAG);
 
 	return (dsobj);
@@ -653,21 +862,24 @@ dsl_snapshot_destroy_one(char *name, void *arg)
 
 	(void) strcat(name, "@");
 	(void) strcat(name, da->snapname);
-	err = dsl_dataset_open(name,
-	    DS_MODE_EXCLUSIVE | DS_MODE_READONLY | DS_MODE_INCONSISTENT,
+	err = dsl_dataset_own(name, DS_MODE_READONLY | DS_MODE_INCONSISTENT,
 	    da->dstg, &ds);
 	cp = strchr(name, '@');
 	*cp = '\0';
-	if (err == ENOENT)
-		return (0);
-	if (err) {
+	if (err == 0) {
+		dsl_dataset_make_exclusive(ds, da->dstg);
+		if (ds->ds_user_ptr) {
+			ds->ds_user_evict_func(ds, ds->ds_user_ptr);
+			ds->ds_user_ptr = NULL;
+		}
+		dsl_sync_task_create(da->dstg, dsl_dataset_destroy_check,
+		    dsl_dataset_destroy_sync, ds, da->dstg, 0);
+	} else if (err == ENOENT) {
+		err = 0;
+	} else {
 		(void) strcpy(da->failed, name);
-		return (err);
 	}
-
-	dsl_sync_task_create(da->dstg, dsl_dataset_destroy_check,
-	    dsl_dataset_destroy_sync, ds, da->dstg, 0);
-	return (0);
+	return (err);
 }
 
 /*
@@ -681,16 +893,8 @@ dsl_snapshots_destroy(char *fsname, char *snapname)
 	struct destroyarg da;
 	dsl_sync_task_t *dst;
 	spa_t *spa;
-	char *cp;
 
-	cp = strchr(fsname, '/');
-	if (cp) {
-		*cp = '\0';
-		err = spa_open(fsname, &spa, FTAG);
-		*cp = '/';
-	} else {
-		err = spa_open(fsname, &spa, FTAG);
-	}
+	err = spa_open(fsname, &spa, FTAG);
 	if (err)
 		return (err);
 	da.dstg = dsl_sync_task_group_create(spa_get_dsl(spa));
@@ -706,17 +910,14 @@ dsl_snapshots_destroy(char *fsname, char *snapname)
 	for (dst = list_head(&da.dstg->dstg_tasks); dst;
 	    dst = list_next(&da.dstg->dstg_tasks, dst)) {
 		dsl_dataset_t *ds = dst->dst_arg1;
+		/*
+		 * Return the file system name that triggered the error
+		 */
 		if (dst->dst_err) {
 			dsl_dataset_name(ds, fsname);
-			cp = strchr(fsname, '@');
-			*cp = '\0';
+			*strchr(fsname, '@') = '\0';
 		}
-		/*
-		 * If it was successful, destroy_sync would have
-		 * closed the ds
-		 */
-		if (err)
-			dsl_dataset_close(ds, DS_MODE_EXCLUSIVE, da.dstg);
+		dsl_dataset_disown(ds, da.dstg);
 	}
 
 	dsl_sync_task_group_destroy(da.dstg);
@@ -724,36 +925,33 @@ dsl_snapshots_destroy(char *fsname, char *snapname)
 	return (err);
 }
 
+/*
+ * ds must be opened as OWNER.  On return (whether successful or not),
+ * ds will be closed and caller can no longer dereference it.
+ */
 int
-dsl_dataset_destroy(const char *name)
+dsl_dataset_destroy(dsl_dataset_t *ds, void *tag)
 {
 	int err;
 	dsl_sync_task_group_t *dstg;
 	objset_t *os;
-	dsl_dataset_t *ds;
 	dsl_dir_t *dd;
 	uint64_t obj;
 
-	if (strchr(name, '@')) {
+	if (dsl_dataset_is_snapshot(ds)) {
 		/* Destroying a snapshot is simpler */
-		err = dsl_dataset_open(name,
-		    DS_MODE_EXCLUSIVE | DS_MODE_READONLY | DS_MODE_INCONSISTENT,
-		    FTAG, &ds);
-		if (err)
-			return (err);
+		dsl_dataset_make_exclusive(ds, tag);
+
+		if (ds->ds_user_ptr) {
+			ds->ds_user_evict_func(ds, ds->ds_user_ptr);
+			ds->ds_user_ptr = NULL;
+		}
 		err = dsl_sync_task_do(ds->ds_dir->dd_pool,
 		    dsl_dataset_destroy_check, dsl_dataset_destroy_sync,
-		    ds, FTAG, 0);
-		if (err)
-			dsl_dataset_close(ds, DS_MODE_EXCLUSIVE, FTAG);
-		return (err);
+		    ds, tag, 0);
+		goto out;
 	}
 
-	err = dmu_objset_open(name, DMU_OST_ANY,
-	    DS_MODE_EXCLUSIVE | DS_MODE_INCONSISTENT, &os);
-	if (err)
-		return (err);
-	ds = os->os->os_dsl_dataset;
 	dd = ds->ds_dir;
 
 	/*
@@ -762,10 +960,12 @@ dsl_dataset_destroy(const char *name)
 	 */
 	err = dsl_sync_task_do(dd->dd_pool, dsl_dataset_destroy_begin_check,
 	    dsl_dataset_destroy_begin_sync, ds, NULL, 0);
-	if (err) {
-		dmu_objset_close(os);
-		return (err);
-	}
+	if (err)
+		goto out;
+
+	err = dmu_objset_open_ds(ds, DMU_OST_ANY, &os);
+	if (err)
+		goto out;
 
 	/*
 	 * remove the objects in open context, so that we won't
@@ -773,66 +973,73 @@ dsl_dataset_destroy(const char *name)
 	 */
 	for (obj = 0; err == 0; err = dmu_object_next(os, &obj, FALSE,
 	    ds->ds_phys->ds_prev_snap_txg)) {
-		dmu_tx_t *tx = dmu_tx_create(os);
-		dmu_tx_hold_free(tx, obj, 0, DMU_OBJECT_END);
-		dmu_tx_hold_bonus(tx, obj);
-		err = dmu_tx_assign(tx, TXG_WAIT);
-		if (err) {
-			/*
-			 * Perhaps there is not enough disk
-			 * space.  Just deal with it from
-			 * dsl_dataset_destroy_sync().
-			 */
-			dmu_tx_abort(tx);
-			continue;
-		}
-		VERIFY(0 == dmu_object_free(os, obj, tx));
-		dmu_tx_commit(tx);
+		/*
+		 * Ignore errors, if there is not enough disk space
+		 * we will deal with it in dsl_dataset_destroy_sync().
+		 */
+		(void) dmu_free_object(os, obj);
 	}
-	/* Make sure it's not dirty before we finish destroying it. */
-	txg_wait_synced(dd->dd_pool, 0);
 
 	dmu_objset_close(os);
 	if (err != ESRCH)
-		return (err);
+		goto out;
+
+	rw_enter(&dd->dd_pool->dp_config_rwlock, RW_READER);
+	err = dsl_dir_open_obj(dd->dd_pool, dd->dd_object, NULL, FTAG, &dd);
+	rw_exit(&dd->dd_pool->dp_config_rwlock);
 
-	err = dsl_dataset_open(name,
-	    DS_MODE_EXCLUSIVE | DS_MODE_READONLY | DS_MODE_INCONSISTENT,
-	    FTAG, &ds);
 	if (err)
-		return (err);
+		goto out;
 
-	err = dsl_dir_open(name, FTAG, &dd, NULL);
-	if (err) {
-		dsl_dataset_close(ds, DS_MODE_EXCLUSIVE, FTAG);
-		return (err);
+	if (ds->ds_user_ptr) {
+		/*
+		 * We need to sync out all in-flight IO before we try
+		 * to evict (the dataset evict func is trying to clear
+		 * the cached entries for this dataset in the ARC).
+		 */
+		txg_wait_synced(dd->dd_pool, 0);
 	}
 
 	/*
 	 * Blow away the dsl_dir + head dataset.
 	 */
+	dsl_dataset_make_exclusive(ds, tag);
+	if (ds->ds_user_ptr) {
+		ds->ds_user_evict_func(ds, ds->ds_user_ptr);
+		ds->ds_user_ptr = NULL;
+	}
 	dstg = dsl_sync_task_group_create(ds->ds_dir->dd_pool);
 	dsl_sync_task_create(dstg, dsl_dataset_destroy_check,
-	    dsl_dataset_destroy_sync, ds, FTAG, 0);
+	    dsl_dataset_destroy_sync, ds, tag, 0);
 	dsl_sync_task_create(dstg, dsl_dir_destroy_check,
 	    dsl_dir_destroy_sync, dd, FTAG, 0);
 	err = dsl_sync_task_group_wait(dstg);
 	dsl_sync_task_group_destroy(dstg);
-	/* if it is successful, *destroy_sync will close the ds+dd */
-	if (err) {
-		dsl_dataset_close(ds, DS_MODE_EXCLUSIVE, FTAG);
+	/* if it is successful, dsl_dir_destroy_sync will close the dd */
+	if (err)
 		dsl_dir_close(dd, FTAG);
-	}
+out:
+	dsl_dataset_disown(ds, tag);
 	return (err);
 }
 
 int
-dsl_dataset_rollback(dsl_dataset_t *ds)
+dsl_dataset_rollback(dsl_dataset_t *ds, dmu_objset_type_t ost)
 {
-	ASSERT3U(ds->ds_open_refcount, ==, DS_REF_MAX);
-	return (dsl_sync_task_do(ds->ds_dir->dd_pool,
+	int err;
+
+	ASSERT(ds->ds_owner);
+
+	dsl_dataset_make_exclusive(ds, ds->ds_owner);
+	err = dsl_sync_task_do(ds->ds_dir->dd_pool,
 	    dsl_dataset_rollback_check, dsl_dataset_rollback_sync,
-	    ds, NULL, 0));
+	    ds, &ost, 0);
+	/* drop exclusive access */
+	mutex_enter(&ds->ds_lock);
+	rw_exit(&ds->ds_rwlock);
+	cv_broadcast(&ds->ds_exclusive_cv);
+	mutex_exit(&ds->ds_lock);
+	return (err);
 }
 
 void *
@@ -904,14 +1111,56 @@ dsl_dataset_dirty(dsl_dataset_t *ds, dmu_tx_t *tx)
 	}
 }
 
+/*
+ * The unique space in the head dataset can be calculated by subtracting
+ * the space used in the most recent snapshot, that is still being used
+ * in this file system, from the space currently in use.  To figure out
+ * the space in the most recent snapshot still in use, we need to take
+ * the total space used in the snapshot and subtract out the space that
+ * has been freed up since the snapshot was taken.
+ */
+static void
+dsl_dataset_recalc_head_uniq(dsl_dataset_t *ds)
+{
+	uint64_t mrs_used;
+	uint64_t dlused, dlcomp, dluncomp;
+
+	ASSERT(ds->ds_object == ds->ds_dir->dd_phys->dd_head_dataset_obj);
+
+	if (ds->ds_phys->ds_prev_snap_obj != 0)
+		mrs_used = ds->ds_prev->ds_phys->ds_used_bytes;
+	else
+		mrs_used = 0;
+
+	VERIFY(0 == bplist_space(&ds->ds_deadlist, &dlused, &dlcomp,
+	    &dluncomp));
+
+	ASSERT3U(dlused, <=, mrs_used);
+	ds->ds_phys->ds_unique_bytes =
+	    ds->ds_phys->ds_used_bytes - (mrs_used - dlused);
+
+	if (!DS_UNIQUE_IS_ACCURATE(ds) &&
+	    spa_version(ds->ds_dir->dd_pool->dp_spa) >=
+	    SPA_VERSION_UNIQUE_ACCURATE)
+		ds->ds_phys->ds_flags |= DS_FLAG_UNIQUE_ACCURATE;
+}
+
+static uint64_t
+dsl_dataset_unique(dsl_dataset_t *ds)
+{
+	if (!DS_UNIQUE_IS_ACCURATE(ds) && !dsl_dataset_is_snapshot(ds))
+		dsl_dataset_recalc_head_uniq(ds);
+
+	return (ds->ds_phys->ds_unique_bytes);
+}
+
 struct killarg {
-	uint64_t *usedp;
-	uint64_t *compressedp;
-	uint64_t *uncompressedp;
+	dsl_dataset_t *ds;
 	zio_t *zio;
 	dmu_tx_t *tx;
 };
 
+/* ARGSUSED */
 static int
 kill_blkptr(traverse_blk_cache_t *bc, spa_t *spa, void *arg)
 {
@@ -920,16 +1169,9 @@ kill_blkptr(traverse_blk_cache_t *bc, spa_t *spa, void *arg)
 
 	ASSERT3U(bc->bc_errno, ==, 0);
 
-	/*
-	 * Since this callback is not called concurrently, no lock is
-	 * needed on the accounting values.
-	 */
-	*ka->usedp += bp_get_dasize(spa, bp);
-	*ka->compressedp += BP_GET_PSIZE(bp);
-	*ka->uncompressedp += BP_GET_UCSIZE(bp);
-	/* XXX check for EIO? */
-	(void) arc_free(ka->zio, spa, ka->tx->tx_txg, bp, NULL, NULL,
-	    ARC_NOWAIT);
+	ASSERT3U(bp->blk_birth, >, ka->ds->ds_phys->ds_prev_snap_txg);
+	(void) dsl_dataset_block_kill(ka->ds, bp, ka->zio, ka->tx);
+
 	return (0);
 }
 
@@ -938,14 +1180,12 @@ static int
 dsl_dataset_rollback_check(void *arg1, void *arg2, dmu_tx_t *tx)
 {
 	dsl_dataset_t *ds = arg1;
+	dmu_objset_type_t *ost = arg2;
 
 	/*
-	 * There must be a previous snapshot.  I suppose we could roll
-	 * it back to being empty (and re-initialize the upper (ZPL)
-	 * layer).  But for now there's no way to do this via the user
-	 * interface.
+	 * We can only roll back to emptyness if it is a ZPL objset.
 	 */
-	if (ds->ds_phys->ds_prev_snap_txg == 0)
+	if (*ost != DMU_OST_ZFS && ds->ds_phys->ds_prev_snap_txg == 0)
 		return (EINVAL);
 
 	/*
@@ -966,13 +1206,44 @@ dsl_dataset_rollback_check(void *arg1, void *arg2, dmu_tx_t *tx)
 
 /* ARGSUSED */
 static void
-dsl_dataset_rollback_sync(void *arg1, void *arg2, dmu_tx_t *tx)
+dsl_dataset_rollback_sync(void *arg1, void *arg2, cred_t *cr, dmu_tx_t *tx)
 {
 	dsl_dataset_t *ds = arg1;
+	dmu_objset_type_t *ost = arg2;
 	objset_t *mos = ds->ds_dir->dd_pool->dp_meta_objset;
 
 	dmu_buf_will_dirty(ds->ds_dbuf, tx);
 
+	/*
+	 * Before the roll back destroy the zil.
+	 */
+	if (ds->ds_user_ptr != NULL) {
+		zil_rollback_destroy(
+		    ((objset_impl_t *)ds->ds_user_ptr)->os_zil, tx);
+
+		/*
+		 * We need to make sure that the objset_impl_t is reopened after
+		 * we do the rollback, otherwise it will have the wrong
+		 * objset_phys_t.  Normally this would happen when this
+		 * dataset-open is closed, thus causing the
+		 * dataset to be immediately evicted.  But when doing "zfs recv
+		 * -F", we reopen the objset before that, so that there is no
+		 * window where the dataset is closed and inconsistent.
+		 */
+		ds->ds_user_evict_func(ds, ds->ds_user_ptr);
+		ds->ds_user_ptr = NULL;
+	}
+
+	/* Transfer space that was freed since last snap back to the head. */
+	{
+		uint64_t used;
+
+		VERIFY(0 == bplist_space_birthrange(&ds->ds_deadlist,
+		    ds->ds_origin_txg, UINT64_MAX, &used));
+		dsl_dir_transfer_space(ds->ds_dir, used,
+		    DD_USED_SNAP, DD_USED_HEAD, tx);
+	}
+
 	/* Zero out the deadlist. */
 	bplist_close(&ds->ds_deadlist);
 	bplist_destroy(mos, ds->ds_phys->ds_deadlist_obj, tx);
@@ -984,39 +1255,65 @@ dsl_dataset_rollback_sync(void *arg1, void *arg2, dmu_tx_t *tx)
 	{
 		/* Free blkptrs that we gave birth to */
 		zio_t *zio;
-		uint64_t used = 0, compressed = 0, uncompressed = 0;
 		struct killarg ka;
 
 		zio = zio_root(tx->tx_pool->dp_spa, NULL, NULL,
 		    ZIO_FLAG_MUSTSUCCEED);
-		ka.usedp = &used;
-		ka.compressedp = &compressed;
-		ka.uncompressedp = &uncompressed;
+		ka.ds = ds;
 		ka.zio = zio;
 		ka.tx = tx;
 		(void) traverse_dsl_dataset(ds, ds->ds_phys->ds_prev_snap_txg,
 		    ADVANCE_POST, kill_blkptr, &ka);
 		(void) zio_wait(zio);
-
-		dsl_dir_diduse_space(ds->ds_dir,
-		    -used, -compressed, -uncompressed, tx);
 	}
 
-	/* Change our contents to that of the prev snapshot */
-	ASSERT3U(ds->ds_prev->ds_object, ==, ds->ds_phys->ds_prev_snap_obj);
-	ds->ds_phys->ds_bp = ds->ds_prev->ds_phys->ds_bp;
-	ds->ds_phys->ds_used_bytes = ds->ds_prev->ds_phys->ds_used_bytes;
-	ds->ds_phys->ds_compressed_bytes =
-	    ds->ds_prev->ds_phys->ds_compressed_bytes;
-	ds->ds_phys->ds_uncompressed_bytes =
-	    ds->ds_prev->ds_phys->ds_uncompressed_bytes;
-	ds->ds_phys->ds_flags = ds->ds_prev->ds_phys->ds_flags;
-	ds->ds_phys->ds_unique_bytes = 0;
+	ASSERT(!(ds->ds_phys->ds_flags & DS_FLAG_UNIQUE_ACCURATE) ||
+	    ds->ds_phys->ds_unique_bytes == 0);
+
+	if (ds->ds_prev && ds->ds_prev != ds->ds_dir->dd_pool->dp_origin_snap) {
+		/* Change our contents to that of the prev snapshot */
+
+		ASSERT3U(ds->ds_prev->ds_object, ==,
+		    ds->ds_phys->ds_prev_snap_obj);
+		ASSERT3U(ds->ds_phys->ds_used_bytes, <=,
+		    ds->ds_prev->ds_phys->ds_used_bytes);
+
+		ds->ds_phys->ds_bp = ds->ds_prev->ds_phys->ds_bp;
+		ds->ds_phys->ds_used_bytes =
+		    ds->ds_prev->ds_phys->ds_used_bytes;
+		ds->ds_phys->ds_compressed_bytes =
+		    ds->ds_prev->ds_phys->ds_compressed_bytes;
+		ds->ds_phys->ds_uncompressed_bytes =
+		    ds->ds_prev->ds_phys->ds_uncompressed_bytes;
+		ds->ds_phys->ds_flags = ds->ds_prev->ds_phys->ds_flags;
+
+		if (ds->ds_prev->ds_phys->ds_next_snap_obj == ds->ds_object) {
+			dmu_buf_will_dirty(ds->ds_prev->ds_dbuf, tx);
+			ds->ds_prev->ds_phys->ds_unique_bytes = 0;
+		}
+	} else {
+		objset_impl_t *osi;
+
+		ASSERT3U(ds->ds_phys->ds_used_bytes, ==, 0);
+		ASSERT3U(ds->ds_phys->ds_compressed_bytes, ==, 0);
+		ASSERT3U(ds->ds_phys->ds_uncompressed_bytes, ==, 0);
 
-	if (ds->ds_prev->ds_phys->ds_next_snap_obj == ds->ds_object) {
-		dmu_buf_will_dirty(ds->ds_prev->ds_dbuf, tx);
-		ds->ds_prev->ds_phys->ds_unique_bytes = 0;
+		bzero(&ds->ds_phys->ds_bp, sizeof (blkptr_t));
+		ds->ds_phys->ds_flags = 0;
+		ds->ds_phys->ds_unique_bytes = 0;
+		if (spa_version(ds->ds_dir->dd_pool->dp_spa) >=
+		    SPA_VERSION_UNIQUE_ACCURATE)
+			ds->ds_phys->ds_flags |= DS_FLAG_UNIQUE_ACCURATE;
+
+		osi = dmu_objset_create_impl(ds->ds_dir->dd_pool->dp_spa, ds,
+		    &ds->ds_phys->ds_bp, *ost, tx);
+#ifdef _KERNEL
+		zfs_create_fs(&osi->os, kcred, NULL, tx);
+#endif
 	}
+
+	spa_history_internal_log(LOG_DS_ROLLBACK, ds->ds_dir->dd_pool->dp_spa,
+	    tx, cr, "dataset = %llu", ds->ds_object);
 }
 
 /* ARGSUSED */
@@ -1024,6 +1321,9 @@ static int
 dsl_dataset_destroy_begin_check(void *arg1, void *arg2, dmu_tx_t *tx)
 {
 	dsl_dataset_t *ds = arg1;
+	objset_t *mos = ds->ds_dir->dd_pool->dp_meta_objset;
+	uint64_t count;
+	int err;
 
 	/*
 	 * Can't delete a head dataset if there are snapshots of it.
@@ -1034,26 +1334,44 @@ dsl_dataset_destroy_begin_check(void *arg1, void *arg2, dmu_tx_t *tx)
 	    ds->ds_prev->ds_phys->ds_next_snap_obj == ds->ds_object)
 		return (EINVAL);
 
+	/*
+	 * This is really a dsl_dir thing, but check it here so that
+	 * we'll be less likely to leave this dataset inconsistent &
+	 * nearly destroyed.
+	 */
+	err = zap_count(mos, ds->ds_dir->dd_phys->dd_child_dir_zapobj, &count);
+	if (err)
+		return (err);
+	if (count != 0)
+		return (EEXIST);
+
 	return (0);
 }
 
 /* ARGSUSED */
 static void
-dsl_dataset_destroy_begin_sync(void *arg1, void *arg2, dmu_tx_t *tx)
+dsl_dataset_destroy_begin_sync(void *arg1, void *arg2, cred_t *cr, dmu_tx_t *tx)
 {
 	dsl_dataset_t *ds = arg1;
+	dsl_pool_t *dp = ds->ds_dir->dd_pool;
 
 	/* Mark it as inconsistent on-disk, in case we crash */
 	dmu_buf_will_dirty(ds->ds_dbuf, tx);
 	ds->ds_phys->ds_flags |= DS_FLAG_INCONSISTENT;
+
+	spa_history_internal_log(LOG_DS_DESTROY_BEGIN, dp->dp_spa, tx,
+	    cr, "dataset = %llu", ds->ds_object);
 }
 
 /* ARGSUSED */
-static int
+int
 dsl_dataset_destroy_check(void *arg1, void *arg2, dmu_tx_t *tx)
 {
 	dsl_dataset_t *ds = arg1;
 
+	/* we have an owner hold, so noone else can destroy us */
+	ASSERT(!DSL_DATASET_IS_DESTROYED(ds));
+
 	/* Can't delete a branch point. */
 	if (ds->ds_phys->ds_num_children > 1)
 		return (EEXIST);
@@ -1078,11 +1396,50 @@ dsl_dataset_destroy_check(void *arg1, void *arg2, dmu_tx_t *tx)
 	return (0);
 }
 
+struct refsarg {
+	kmutex_t lock;
+	boolean_t gone;
+	kcondvar_t cv;
+};
+
+/* ARGSUSED */
+static void
+dsl_dataset_refs_gone(dmu_buf_t *db, void *argv)
+{
+	struct refsarg *arg = argv;
+
+	mutex_enter(&arg->lock);
+	arg->gone = TRUE;
+	cv_signal(&arg->cv);
+	mutex_exit(&arg->lock);
+}
+
 static void
-dsl_dataset_destroy_sync(void *arg1, void *tag, dmu_tx_t *tx)
+dsl_dataset_drain_refs(dsl_dataset_t *ds, void *tag)
+{
+	struct refsarg arg;
+
+	mutex_init(&arg.lock, NULL, MUTEX_DEFAULT, NULL);
+	cv_init(&arg.cv, NULL, CV_DEFAULT, NULL);
+	arg.gone = FALSE;
+	(void) dmu_buf_update_user(ds->ds_dbuf, ds, &arg, &ds->ds_phys,
+	    dsl_dataset_refs_gone);
+	dmu_buf_rele(ds->ds_dbuf, tag);
+	mutex_enter(&arg.lock);
+	while (!arg.gone)
+		cv_wait(&arg.cv, &arg.lock);
+	ASSERT(arg.gone);
+	mutex_exit(&arg.lock);
+	ds->ds_dbuf = NULL;
+	ds->ds_phys = NULL;
+	mutex_destroy(&arg.lock);
+	cv_destroy(&arg.cv);
+}
+
+void
+dsl_dataset_destroy_sync(void *arg1, void *tag, cred_t *cr, dmu_tx_t *tx)
 {
 	dsl_dataset_t *ds = arg1;
-	uint64_t used = 0, compressed = 0, uncompressed = 0;
 	zio_t *zio;
 	int err;
 	int after_branch_point = FALSE;
@@ -1091,29 +1448,53 @@ dsl_dataset_destroy_sync(void *arg1, void *tag, dmu_tx_t *tx)
 	dsl_dataset_t *ds_prev = NULL;
 	uint64_t obj;
 
-	ASSERT3U(ds->ds_open_refcount, ==, DS_REF_MAX);
+	ASSERT(ds->ds_owner);
 	ASSERT3U(ds->ds_phys->ds_num_children, <=, 1);
 	ASSERT(ds->ds_prev == NULL ||
 	    ds->ds_prev->ds_phys->ds_next_snap_obj != ds->ds_object);
 	ASSERT3U(ds->ds_phys->ds_bp.blk_birth, <=, tx->tx_txg);
 
+	/* signal any waiters that this dataset is going away */
+	mutex_enter(&ds->ds_lock);
+	ds->ds_owner = dsl_reaper;
+	cv_broadcast(&ds->ds_exclusive_cv);
+	mutex_exit(&ds->ds_lock);
+
+	/* Remove our reservation */
+	if (ds->ds_reserved != 0) {
+		uint64_t val = 0;
+		dsl_dataset_set_reservation_sync(ds, &val, cr, tx);
+		ASSERT3U(ds->ds_reserved, ==, 0);
+	}
+
 	ASSERT(RW_WRITE_HELD(&dp->dp_config_rwlock));
 
+	dsl_pool_ds_destroyed(ds, tx);
+
 	obj = ds->ds_object;
 
 	if (ds->ds_phys->ds_prev_snap_obj != 0) {
 		if (ds->ds_prev) {
 			ds_prev = ds->ds_prev;
 		} else {
-			VERIFY(0 == dsl_dataset_open_obj(dp,
-			    ds->ds_phys->ds_prev_snap_obj, NULL,
-			    DS_MODE_NONE, FTAG, &ds_prev));
+			VERIFY(0 == dsl_dataset_hold_obj(dp,
+			    ds->ds_phys->ds_prev_snap_obj, FTAG, &ds_prev));
 		}
 		after_branch_point =
 		    (ds_prev->ds_phys->ds_next_snap_obj != obj);
 
 		dmu_buf_will_dirty(ds_prev->ds_dbuf, tx);
 		if (after_branch_point &&
+		    ds_prev->ds_phys->ds_next_clones_obj != 0) {
+			VERIFY(0 == zap_remove_int(mos,
+			    ds_prev->ds_phys->ds_next_clones_obj, obj, tx));
+			if (ds->ds_phys->ds_next_snap_obj != 0) {
+				VERIFY(0 == zap_add_int(mos,
+				    ds_prev->ds_phys->ds_next_clones_obj,
+				    ds->ds_phys->ds_next_snap_obj, tx));
+			}
+		}
+		if (after_branch_point &&
 		    ds->ds_phys->ds_next_snap_obj == 0) {
 			/* This clone is toast. */
 			ASSERT(ds_prev->ds_phys->ds_num_children > 1);
@@ -1130,14 +1511,15 @@ dsl_dataset_destroy_sync(void *arg1, void *tag, dmu_tx_t *tx)
 		blkptr_t bp;
 		dsl_dataset_t *ds_next;
 		uint64_t itor = 0;
+		uint64_t old_unique;
+		int64_t used = 0, compressed = 0, uncompressed = 0;
 
-		spa_scrub_restart(dp->dp_spa, tx->tx_txg);
-
-		VERIFY(0 == dsl_dataset_open_obj(dp,
-		    ds->ds_phys->ds_next_snap_obj, NULL,
-		    DS_MODE_NONE, FTAG, &ds_next));
+		VERIFY(0 == dsl_dataset_hold_obj(dp,
+		    ds->ds_phys->ds_next_snap_obj, FTAG, &ds_next));
 		ASSERT3U(ds_next->ds_phys->ds_prev_snap_obj, ==, obj);
 
+		old_unique = dsl_dataset_unique(ds_next);
+
 		dmu_buf_will_dirty(ds_next->ds_dbuf, tx);
 		ds_next->ds_phys->ds_prev_snap_obj =
 		    ds->ds_phys->ds_prev_snap_obj;
@@ -1154,8 +1536,7 @@ dsl_dataset_destroy_sync(void *arg1, void *tag, dmu_tx_t *tx)
 		 *
 		 * XXX we're doing this long task with the config lock held
 		 */
-		while (bplist_iterate(&ds_next->ds_deadlist, &itor,
-		    &bp) == 0) {
+		while (bplist_iterate(&ds_next->ds_deadlist, &itor, &bp) == 0) {
 			if (bp.blk_birth <= ds->ds_phys->ds_prev_snap_txg) {
 				VERIFY(0 == bplist_enqueue(&ds->ds_deadlist,
 				    &bp, tx));
@@ -1170,16 +1551,23 @@ dsl_dataset_destroy_sync(void *arg1, void *tag, dmu_tx_t *tx)
 				compressed += BP_GET_PSIZE(&bp);
 				uncompressed += BP_GET_UCSIZE(&bp);
 				/* XXX check return value? */
-				(void) arc_free(zio, dp->dp_spa, tx->tx_txg,
+				(void) dsl_free(zio, dp, tx->tx_txg,
 				    &bp, NULL, NULL, ARC_NOWAIT);
 			}
 		}
 
+		ASSERT3U(used, ==, ds->ds_phys->ds_unique_bytes);
+
+		/* change snapused */
+		dsl_dir_diduse_space(ds->ds_dir, DD_USED_SNAP,
+		    -used, -compressed, -uncompressed, tx);
+
 		/* free next's deadlist */
 		bplist_close(&ds_next->ds_deadlist);
 		bplist_destroy(mos, ds_next->ds_phys->ds_deadlist_obj, tx);
 
 		/* set next's deadlist to our deadlist */
+		bplist_close(&ds->ds_deadlist);
 		ds_next->ds_phys->ds_deadlist_obj =
 		    ds->ds_phys->ds_deadlist_obj;
 		VERIFY(0 == bplist_open(&ds_next->ds_deadlist, mos,
@@ -1200,51 +1588,50 @@ dsl_dataset_destroy_sync(void *arg1, void *tag, dmu_tx_t *tx)
 			 * config lock held
 			 */
 			dsl_dataset_t *ds_after_next;
+			uint64_t space;
 
-			VERIFY(0 == dsl_dataset_open_obj(dp,
-			    ds_next->ds_phys->ds_next_snap_obj, NULL,
-			    DS_MODE_NONE, FTAG, &ds_after_next));
-			itor = 0;
-			while (bplist_iterate(&ds_after_next->ds_deadlist,
-			    &itor, &bp) == 0) {
-				if (bp.blk_birth >
-				    ds->ds_phys->ds_prev_snap_txg &&
-				    bp.blk_birth <=
-				    ds->ds_phys->ds_creation_txg) {
-					ds_next->ds_phys->ds_unique_bytes +=
-					    bp_get_dasize(dp->dp_spa, &bp);
-				}
-			}
+			VERIFY(0 == dsl_dataset_hold_obj(dp,
+			    ds_next->ds_phys->ds_next_snap_obj,
+			    FTAG, &ds_a