1 files changed, 263 insertions, 0 deletions
diff --git a/usr.sbin/makefs/zfs/objset.c b/usr.sbin/makefs/zfs/objset.c
new file mode 100644
index 000000000000..f47953ac4339
--- /dev/null
+++ b/usr.sbin/makefs/zfs/objset.c
@@ -0,0 +1,263 @@
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2022 The FreeBSD Foundation
+ *
+ * This software was developed by Mark Johnston under sponsorship from
+ * the FreeBSD Foundation.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/param.h>
+#include <assert.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <util.h>
+
+#include "zfs.h"
+
+#define	DNODES_PER_CHUNK	(MAXBLOCKSIZE / sizeof(dnode_phys_t))
+
+struct objset_dnode_chunk {
+	dnode_phys_t	buf[DNODES_PER_CHUNK];
+	unsigned int	nextfree;
+	STAILQ_ENTRY(objset_dnode_chunk) next;
+};
+
+typedef struct zfs_objset {
+	/* Physical object set. */
+	objset_phys_t	*phys;
+	off_t		osloc;
+	off_t		osblksz;
+	blkptr_t	osbp;		/* set in objset_write() */
+
+	/* Accounting. */
+	off_t		space;		/* bytes allocated to this objset */
+
+	/* dnode allocator. */
+	uint64_t	dnodecount;
+	STAILQ_HEAD(, objset_dnode_chunk) dnodechunks;
+} zfs_objset_t;
+
+static void
+dnode_init(dnode_phys_t *dnode, uint8_t type, uint8_t bonustype,
+    uint16_t bonuslen)
+{
+	dnode->dn_indblkshift = MAXBLOCKSHIFT;
+	dnode->dn_type = type;
+	dnode->dn_bonustype = bonustype;
+	dnode->dn_bonuslen = bonuslen;
+	dnode->dn_checksum = ZIO_CHECKSUM_FLETCHER_4;
+	dnode->dn_nlevels = 1;
+	dnode->dn_nblkptr = 1;
+	dnode->dn_flags = DNODE_FLAG_USED_BYTES;
+}
+
+zfs_objset_t *
+objset_alloc(zfs_opt_t *zfs, uint64_t type)
+{
+	struct objset_dnode_chunk *chunk;
+	zfs_objset_t *os;
+
+	os = ecalloc(1, sizeof(*os));
+	os->osblksz = sizeof(objset_phys_t);
+	os->osloc = objset_space_alloc(zfs, os, &os->osblksz);
+
+	/*
+	 * Object ID zero is always reserved for the meta dnode, which is
+	 * embedded in the objset itself.
+	 */
+	STAILQ_INIT(&os->dnodechunks);
+	chunk = ecalloc(1, sizeof(*chunk));
+	chunk->nextfree = 1;
+	STAILQ_INSERT_HEAD(&os->dnodechunks, chunk, next);
+	os->dnodecount = 1;
+
+	os->phys = ecalloc(1, os->osblksz);
+	os->phys->os_type = type;
+
+	dnode_init(&os->phys->os_meta_dnode, DMU_OT_DNODE, DMU_OT_NONE, 0);
+	os->phys->os_meta_dnode.dn_datablkszsec =
+	    DNODE_BLOCK_SIZE >> MINBLOCKSHIFT;
+
+	return (os);
+}
+
+/*
+ * Write the dnode array and physical object set to disk.
+ */
+static void
+_objset_write(zfs_opt_t *zfs, zfs_objset_t *os, struct dnode_cursor *c,
+    off_t loc)
+{
+	struct objset_dnode_chunk *chunk, *tmp;
+	unsigned int total;
+
+	/*
+	 * Write out the dnode array, i.e., the meta-dnode.  For some reason its
+	 * data blocks must be 16KB in size no matter how large the array is.
+	 */
+	total = 0;
+	STAILQ_FOREACH_SAFE(chunk, &os->dnodechunks, next, tmp) {
+		unsigned int i;
+
+		assert(chunk->nextfree > 0);
+		assert(chunk->nextfree <= os->dnodecount);
+		assert(chunk->nextfree <= DNODES_PER_CHUNK);
+
+		for (i = 0; i < chunk->nextfree; i += DNODES_PER_BLOCK) {
+			blkptr_t *bp;
+			uint64_t fill;
+
+			if (chunk->nextfree - i < DNODES_PER_BLOCK)
+				fill = DNODES_PER_BLOCK - (chunk->nextfree - i);
+			else
+				fill = 0;
+			bp = dnode_cursor_next(zfs, c,
+			    (total + i) * sizeof(dnode_phys_t));
+			vdev_pwrite_dnode_indir(zfs, &os->phys->os_meta_dnode,
+			    0, fill, chunk->buf + i, DNODE_BLOCK_SIZE, loc, bp);
+			loc += DNODE_BLOCK_SIZE;
+		}
+		total += i;
+
+		free(chunk);
+	}
+	dnode_cursor_finish(zfs, c);
+	STAILQ_INIT(&os->dnodechunks);
+
+	/*
+	 * Write the object set itself.  The saved block pointer will be copied
+	 * into the referencing DSL dataset or the uberblocks.
+	 */
+	vdev_pwrite_data(zfs, DMU_OT_OBJSET, ZIO_CHECKSUM_FLETCHER_4, 0,
+	    os->dnodecount - 1, os->phys, os->osblksz, os->osloc, &os->osbp);
+}
+
+void
+objset_write(zfs_opt_t *zfs, zfs_objset_t *os)
+{
+	struct dnode_cursor *c;
+	off_t dnodeloc, dnodesz;
+	uint64_t dnodecount;
+
+	/*
+	 * There is a chicken-and-egg problem here when writing the MOS: we
+	 * cannot write space maps before we're finished allocating space from
+	 * the vdev, and we can't write the MOS without having allocated space
+	 * for indirect dnode blocks.  Thus, rather than lazily allocating
+	 * indirect blocks for the meta-dnode (which would be simpler), they are
+	 * allocated up-front and before writing space maps.
+	 */
+	dnodecount = os->dnodecount;
+	if (os == zfs->mos)
+		dnodecount += zfs->mscount;
+	dnodesz = dnodecount * sizeof(dnode_phys_t);
+	c = dnode_cursor_init(zfs, os, &os->phys->os_meta_dnode, dnodesz,
+	    DNODE_BLOCK_SIZE);
+	dnodesz = roundup2(dnodesz, DNODE_BLOCK_SIZE);
+	dnodeloc = objset_space_alloc(zfs, os, &dnodesz);
+
+	if (os == zfs->mos) {
+		vdev_spacemap_write(zfs);
+
+		/*
+		 * We've finished allocating space, account for it in $MOS and
+		 * in the parent directory.
+		 */
+		dsl_dir_root_finalize(zfs, os->space);
+	}
+	_objset_write(zfs, os, c, dnodeloc);
+}
+
+dnode_phys_t *
+objset_dnode_bonus_alloc(zfs_objset_t *os, uint8_t type, uint8_t bonustype,
+    uint16_t bonuslen, uint64_t *idp)
+{
+	struct objset_dnode_chunk *chunk;
+	dnode_phys_t *dnode;
+
+	assert(bonuslen <= DN_OLD_MAX_BONUSLEN);
+	assert(!STAILQ_EMPTY(&os->dnodechunks));
+
+	chunk = STAILQ_LAST(&os->dnodechunks, objset_dnode_chunk, next);
+	if (chunk->nextfree == DNODES_PER_CHUNK) {
+		chunk = ecalloc(1, sizeof(*chunk));
+		STAILQ_INSERT_TAIL(&os->dnodechunks, chunk, next);
+	}
+	*idp = os->dnodecount++;
+	dnode = &chunk->buf[chunk->nextfree++];
+	dnode_init(dnode, type, bonustype, bonuslen);
+	dnode->dn_datablkszsec = os->osblksz >> MINBLOCKSHIFT;
+	return (dnode);
+}
+
+dnode_phys_t *
+objset_dnode_alloc(zfs_objset_t *os, uint8_t type, uint64_t *idp)
+{
+	return (objset_dnode_bonus_alloc(os, type, DMU_OT_NONE, 0, idp));
+}
+
+/*
+ * Look up a physical dnode by ID.  This is not used often so a linear search is
+ * fine.
+ */
+dnode_phys_t *
+objset_dnode_lookup(zfs_objset_t *os, uint64_t id)
+{
+	struct objset_dnode_chunk *chunk;
+
+	assert(id > 0);
+	assert(id < os->dnodecount);
+
+	STAILQ_FOREACH(chunk, &os->dnodechunks, next) {
+		if (id < DNODES_PER_CHUNK)
+			return (&chunk->buf[id]);
+		id -= DNODES_PER_CHUNK;
+	}
+	assert(0);
+	return (NULL);
+}
+
+off_t
+objset_space_alloc(zfs_opt_t *zfs, zfs_objset_t *os, off_t *lenp)
+{
+	off_t loc;
+
+	loc = vdev_space_alloc(zfs, lenp);
+	os->space += *lenp;
+	return (loc);
+}
+
+uint64_t
+objset_space(const zfs_objset_t *os)
+{
+	return (os->space);
+}
+
+void
+objset_root_blkptr_copy(const zfs_objset_t *os, blkptr_t *bp)
+{
+	memcpy(bp, &os->osbp, sizeof(blkptr_t));
+}