diff options
Diffstat (limited to 'sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dnode.c')
| -rw-r--r-- | sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dnode.c | 2081 |
1 files changed, 2081 insertions, 0 deletions
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dnode.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dnode.c new file mode 100644 index 000000000000..c64f68545f71 --- /dev/null +++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dnode.c @@ -0,0 +1,2081 @@ +/* + * 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 (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved. + * Copyright (c) 2012, 2017 by Delphix. All rights reserved. + * Copyright (c) 2014 Spectra Logic Corporation, All rights reserved. + * Copyright (c) 2014 Integros [integros.com] + * Copyright 2017 RackTop Systems. + */ + +#include <sys/zfs_context.h> +#include <sys/dbuf.h> +#include <sys/dnode.h> +#include <sys/dmu.h> +#include <sys/dmu_impl.h> +#include <sys/dmu_tx.h> +#include <sys/dmu_objset.h> +#include <sys/dsl_dir.h> +#include <sys/dsl_dataset.h> +#include <sys/spa.h> +#include <sys/zio.h> +#include <sys/dmu_zfetch.h> +#include <sys/range_tree.h> + +static kmem_cache_t *dnode_cache; +/* + * Define DNODE_STATS to turn on statistic gathering. By default, it is only + * turned on when DEBUG is also defined. + */ +#ifdef DEBUG +#define DNODE_STATS +#endif /* DEBUG */ + +#ifdef DNODE_STATS +#define DNODE_STAT_ADD(stat) ((stat)++) +#else +#define DNODE_STAT_ADD(stat) /* nothing */ +#endif /* DNODE_STATS */ + +static dnode_phys_t dnode_phys_zero; + +int zfs_default_bs = SPA_MINBLOCKSHIFT; +int zfs_default_ibs = DN_MAX_INDBLKSHIFT; + +SYSCTL_DECL(_vfs_zfs); +SYSCTL_INT(_vfs_zfs, OID_AUTO, default_bs, CTLFLAG_RWTUN, + &zfs_default_bs, 0, "Default dnode block shift"); +SYSCTL_INT(_vfs_zfs, OID_AUTO, default_ibs, CTLFLAG_RWTUN, + &zfs_default_ibs, 0, "Default dnode indirect block shift"); + +#ifdef illumos +#ifdef _KERNEL +static kmem_cbrc_t dnode_move(void *, void *, size_t, void *); +#endif /* _KERNEL */ +#endif + +static int +dbuf_compare(const void *x1, const void *x2) +{ + const dmu_buf_impl_t *d1 = x1; + const dmu_buf_impl_t *d2 = x2; + + if (d1->db_level < d2->db_level) { + return (-1); + } + if (d1->db_level > d2->db_level) { + return (1); + } + + if (d1->db_blkid < d2->db_blkid) { + return (-1); + } + if (d1->db_blkid > d2->db_blkid) { + return (1); + } + + if (d1->db_state == DB_SEARCH) { + ASSERT3S(d2->db_state, !=, DB_SEARCH); + return (-1); + } else if (d2->db_state == DB_SEARCH) { + ASSERT3S(d1->db_state, !=, DB_SEARCH); + return (1); + } + + if ((uintptr_t)d1 < (uintptr_t)d2) { + return (-1); + } + if ((uintptr_t)d1 > (uintptr_t)d2) { + return (1); + } + return (0); +} + +/* ARGSUSED */ +static int +dnode_cons(void *arg, void *unused, int kmflag) +{ + dnode_t *dn = arg; + int i; + + rw_init(&dn->dn_struct_rwlock, NULL, RW_DEFAULT, NULL); + mutex_init(&dn->dn_mtx, NULL, MUTEX_DEFAULT, NULL); + mutex_init(&dn->dn_dbufs_mtx, NULL, MUTEX_DEFAULT, NULL); + cv_init(&dn->dn_notxholds, NULL, CV_DEFAULT, NULL); + + /* + * Every dbuf has a reference, and dropping a tracked reference is + * O(number of references), so don't track dn_holds. + */ + refcount_create_untracked(&dn->dn_holds); + refcount_create(&dn->dn_tx_holds); + list_link_init(&dn->dn_link); + + bzero(&dn->dn_next_nblkptr[0], sizeof (dn->dn_next_nblkptr)); + bzero(&dn->dn_next_nlevels[0], sizeof (dn->dn_next_nlevels)); + bzero(&dn->dn_next_indblkshift[0], sizeof (dn->dn_next_indblkshift)); + bzero(&dn->dn_next_bonustype[0], sizeof (dn->dn_next_bonustype)); + bzero(&dn->dn_rm_spillblk[0], sizeof (dn->dn_rm_spillblk)); + bzero(&dn->dn_next_bonuslen[0], sizeof (dn->dn_next_bonuslen)); + bzero(&dn->dn_next_blksz[0], sizeof (dn->dn_next_blksz)); + + for (i = 0; i < TXG_SIZE; i++) { + list_link_init(&dn->dn_dirty_link[i]); + dn->dn_free_ranges[i] = NULL; + list_create(&dn->dn_dirty_records[i], + sizeof (dbuf_dirty_record_t), + offsetof(dbuf_dirty_record_t, dr_dirty_node)); + } + + dn->dn_allocated_txg = 0; + dn->dn_free_txg = 0; + dn->dn_assigned_txg = 0; + dn->dn_dirtyctx = 0; + dn->dn_dirtyctx_firstset = NULL; + dn->dn_bonus = NULL; + dn->dn_have_spill = B_FALSE; + dn->dn_zio = NULL; + dn->dn_oldused = 0; + dn->dn_oldflags = 0; + dn->dn_olduid = 0; + dn->dn_oldgid = 0; + dn->dn_newuid = 0; + dn->dn_newgid = 0; + dn->dn_id_flags = 0; + + dn->dn_dbufs_count = 0; + avl_create(&dn->dn_dbufs, dbuf_compare, sizeof (dmu_buf_impl_t), + offsetof(dmu_buf_impl_t, db_link)); + + dn->dn_moved = 0; + POINTER_INVALIDATE(&dn->dn_objset); + return (0); +} + +/* ARGSUSED */ +static void +dnode_dest(void *arg, void *unused) +{ + int i; + dnode_t *dn = arg; + + rw_destroy(&dn->dn_struct_rwlock); + mutex_destroy(&dn->dn_mtx); + mutex_destroy(&dn->dn_dbufs_mtx); + cv_destroy(&dn->dn_notxholds); + refcount_destroy(&dn->dn_holds); + refcount_destroy(&dn->dn_tx_holds); + ASSERT(!list_link_active(&dn->dn_link)); + + for (i = 0; i < TXG_SIZE; i++) { + ASSERT(!list_link_active(&dn->dn_dirty_link[i])); + ASSERT3P(dn->dn_free_ranges[i], ==, NULL); + list_destroy(&dn->dn_dirty_records[i]); + ASSERT0(dn->dn_next_nblkptr[i]); + ASSERT0(dn->dn_next_nlevels[i]); + ASSERT0(dn->dn_next_indblkshift[i]); + ASSERT0(dn->dn_next_bonustype[i]); + ASSERT0(dn->dn_rm_spillblk[i]); + ASSERT0(dn->dn_next_bonuslen[i]); + ASSERT0(dn->dn_next_blksz[i]); + } + + ASSERT0(dn->dn_allocated_txg); + ASSERT0(dn->dn_free_txg); + ASSERT0(dn->dn_assigned_txg); + ASSERT0(dn->dn_dirtyctx); + ASSERT3P(dn->dn_dirtyctx_firstset, ==, NULL); + ASSERT3P(dn->dn_bonus, ==, NULL); + ASSERT(!dn->dn_have_spill); + ASSERT3P(dn->dn_zio, ==, NULL); + ASSERT0(dn->dn_oldused); + ASSERT0(dn->dn_oldflags); + ASSERT0(dn->dn_olduid); + ASSERT0(dn->dn_oldgid); + ASSERT0(dn->dn_newuid); + ASSERT0(dn->dn_newgid); + ASSERT0(dn->dn_id_flags); + + ASSERT0(dn->dn_dbufs_count); + avl_destroy(&dn->dn_dbufs); +} + +void +dnode_init(void) +{ + ASSERT(dnode_cache == NULL); + dnode_cache = kmem_cache_create("dnode_t", + sizeof (dnode_t), + 0, dnode_cons, dnode_dest, NULL, NULL, NULL, 0); +#ifdef _KERNEL + kmem_cache_set_move(dnode_cache, dnode_move); +#endif /* _KERNEL */ +} + +void +dnode_fini(void) +{ + kmem_cache_destroy(dnode_cache); + dnode_cache = NULL; +} + + +#ifdef ZFS_DEBUG +void +dnode_verify(dnode_t *dn) +{ + int drop_struct_lock = FALSE; + + ASSERT(dn->dn_phys); + ASSERT(dn->dn_objset); + ASSERT(dn->dn_handle->dnh_dnode == dn); + + ASSERT(DMU_OT_IS_VALID(dn->dn_phys->dn_type)); + + if (!(zfs_flags & ZFS_DEBUG_DNODE_VERIFY)) + return; + + if (!RW_WRITE_HELD(&dn->dn_struct_rwlock)) { + rw_enter(&dn->dn_struct_rwlock, RW_READER); + drop_struct_lock = TRUE; + } + if (dn->dn_phys->dn_type != DMU_OT_NONE || dn->dn_allocated_txg != 0) { + int i; + ASSERT3U(dn->dn_indblkshift, >=, 0); + ASSERT3U(dn->dn_indblkshift, <=, SPA_MAXBLOCKSHIFT); + if (dn->dn_datablkshift) { + ASSERT3U(dn->dn_datablkshift, >=, SPA_MINBLOCKSHIFT); + ASSERT3U(dn->dn_datablkshift, <=, SPA_MAXBLOCKSHIFT); + ASSERT3U(1<<dn->dn_datablkshift, ==, dn->dn_datablksz); + } + ASSERT3U(dn->dn_nlevels, <=, 30); + ASSERT(DMU_OT_IS_VALID(dn->dn_type)); + ASSERT3U(dn->dn_nblkptr, >=, 1); + ASSERT3U(dn->dn_nblkptr, <=, DN_MAX_NBLKPTR); + ASSERT3U(dn->dn_bonuslen, <=, DN_MAX_BONUSLEN); + ASSERT3U(dn->dn_datablksz, ==, + dn->dn_datablkszsec << SPA_MINBLOCKSHIFT); + ASSERT3U(ISP2(dn->dn_datablksz), ==, dn->dn_datablkshift != 0); + ASSERT3U((dn->dn_nblkptr - 1) * sizeof (blkptr_t) + + dn->dn_bonuslen, <=, DN_MAX_BONUSLEN); + for (i = 0; i < TXG_SIZE; i++) { + ASSERT3U(dn->dn_next_nlevels[i], <=, dn->dn_nlevels); + } + } + if (dn->dn_phys->dn_type != DMU_OT_NONE) + ASSERT3U(dn->dn_phys->dn_nlevels, <=, dn->dn_nlevels); + ASSERT(DMU_OBJECT_IS_SPECIAL(dn->dn_object) || dn->dn_dbuf != NULL); + if (dn->dn_dbuf != NULL) { + ASSERT3P(dn->dn_phys, ==, + (dnode_phys_t *)dn->dn_dbuf->db.db_data + + (dn->dn_object % (dn->dn_dbuf->db.db_size >> DNODE_SHIFT))); + } + if (drop_struct_lock) + rw_exit(&dn->dn_struct_rwlock); +} +#endif + +void +dnode_byteswap(dnode_phys_t *dnp) +{ + uint64_t *buf64 = (void*)&dnp->dn_blkptr; + int i; + + if (dnp->dn_type == DMU_OT_NONE) { + bzero(dnp, sizeof (dnode_phys_t)); + return; + } + + dnp->dn_datablkszsec = BSWAP_16(dnp->dn_datablkszsec); + dnp->dn_bonuslen = BSWAP_16(dnp->dn_bonuslen); + dnp->dn_maxblkid = BSWAP_64(dnp->dn_maxblkid); + dnp->dn_used = BSWAP_64(dnp->dn_used); + + /* + * dn_nblkptr is only one byte, so it's OK to read it in either + * byte order. We can't read dn_bouslen. + */ + ASSERT(dnp->dn_indblkshift <= SPA_MAXBLOCKSHIFT); + ASSERT(dnp->dn_nblkptr <= DN_MAX_NBLKPTR); + for (i = 0; i < dnp->dn_nblkptr * sizeof (blkptr_t)/8; i++) + buf64[i] = BSWAP_64(buf64[i]); + + /* + * OK to check dn_bonuslen for zero, because it won't matter if + * we have the wrong byte order. This is necessary because the + * dnode dnode is smaller than a regular dnode. + */ + if (dnp->dn_bonuslen != 0) { + /* + * Note that the bonus length calculated here may be + * longer than the actual bonus buffer. This is because + * we always put the bonus buffer after the last block + * pointer (instead of packing it against the end of the + * dnode buffer). + */ + int off = (dnp->dn_nblkptr-1) * sizeof (blkptr_t); + size_t len = DN_MAX_BONUSLEN - off; + ASSERT(DMU_OT_IS_VALID(dnp->dn_bonustype)); + dmu_object_byteswap_t byteswap = + DMU_OT_BYTESWAP(dnp->dn_bonustype); + dmu_ot_byteswap[byteswap].ob_func(dnp->dn_bonus + off, len); + } + + /* Swap SPILL block if we have one */ + if (dnp->dn_flags & DNODE_FLAG_SPILL_BLKPTR) + byteswap_uint64_array(&dnp->dn_spill, sizeof (blkptr_t)); + +} + +void +dnode_buf_byteswap(void *vbuf, size_t size) +{ + dnode_phys_t *buf = vbuf; + int i; + + ASSERT3U(sizeof (dnode_phys_t), ==, (1<<DNODE_SHIFT)); + ASSERT((size & (sizeof (dnode_phys_t)-1)) == 0); + + size >>= DNODE_SHIFT; + for (i = 0; i < size; i++) { + dnode_byteswap(buf); + buf++; + } +} + +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); +} + +void +dnode_setbonus_type(dnode_t *dn, dmu_object_type_t newtype, dmu_tx_t *tx) +{ + ASSERT3U(refcount_count(&dn->dn_holds), >=, 1); + dnode_setdirty(dn, tx); + rw_enter(&dn->dn_struct_rwlock, RW_WRITER); + dn->dn_bonustype = newtype; + dn->dn_next_bonustype[tx->tx_txg & TXG_MASK] = dn->dn_bonustype; + rw_exit(&dn->dn_struct_rwlock); +} + +void +dnode_rm_spill(dnode_t *dn, dmu_tx_t *tx) +{ + ASSERT3U(refcount_count(&dn->dn_holds), >=, 1); + ASSERT(RW_WRITE_HELD(&dn->dn_struct_rwlock)); + dnode_setdirty(dn, tx); + dn->dn_rm_spillblk[tx->tx_txg&TXG_MASK] = DN_KILL_SPILLBLK; + dn->dn_have_spill = B_FALSE; +} + +static void +dnode_setdblksz(dnode_t *dn, int size) +{ + ASSERT0(P2PHASE(size, SPA_MINBLOCKSIZE)); + ASSERT3U(size, <=, SPA_MAXBLOCKSIZE); + ASSERT3U(size, >=, SPA_MINBLOCKSIZE); + ASSERT3U(size >> SPA_MINBLOCKSHIFT, <, + 1<<(sizeof (dn->dn_phys->dn_datablkszsec) * 8)); + dn->dn_datablksz = size; + dn->dn_datablkszsec = size >> SPA_MINBLOCKSHIFT; + dn->dn_datablkshift = ISP2(size) ? highbit64(size - 1) : 0; +} + +static dnode_t * +dnode_create(objset_t *os, dnode_phys_t *dnp, dmu_buf_impl_t *db, + uint64_t object, dnode_handle_t *dnh) +{ + dnode_t *dn; + + dn = kmem_cache_alloc(dnode_cache, KM_SLEEP); +#ifdef _KERNEL + ASSERT(!POINTER_IS_VALID(dn->dn_objset)); +#endif /* _KERNEL */ + dn->dn_moved = 0; + + /* + * Defer setting dn_objset until the dnode is ready to be a candidate + * for the dnode_move() callback. + */ + dn->dn_object = object; + dn->dn_dbuf = db; + dn->dn_handle = dnh; + dn->dn_phys = dnp; + + if (dnp->dn_datablkszsec) { + dnode_setdblksz(dn, dnp->dn_datablkszsec << SPA_MINBLOCKSHIFT); + } else { + dn->dn_datablksz = 0; + dn->dn_datablkszsec = 0; + dn->dn_datablkshift = 0; + } + dn->dn_indblkshift = dnp->dn_indblkshift; + dn->dn_nlevels = dnp->dn_nlevels; + dn->dn_type = dnp->dn_type; + dn->dn_nblkptr = dnp->dn_nblkptr; + dn->dn_checksum = dnp->dn_checksum; + dn->dn_compress = dnp->dn_compress; + dn->dn_bonustype = dnp->dn_bonustype; + dn->dn_bonuslen = dnp->dn_bonuslen; + dn->dn_maxblkid = dnp->dn_maxblkid; + dn->dn_have_spill = ((dnp->dn_flags & DNODE_FLAG_SPILL_BLKPTR) != 0); + dn->dn_id_flags = 0; + + dmu_zfetch_init(&dn->dn_zfetch, dn); + + ASSERT(DMU_OT_IS_VALID(dn->dn_phys->dn_type)); + + mutex_enter(&os->os_lock); + if (dnh->dnh_dnode != NULL) { + /* Lost the allocation race. */ + mutex_exit(&os->os_lock); + kmem_cache_free(dnode_cache, dn); + return (dnh->dnh_dnode); + } + + /* + * Exclude special dnodes from os_dnodes so an empty os_dnodes + * signifies that the special dnodes have no references from + * their children (the entries in os_dnodes). This allows + * dnode_destroy() to easily determine if the last child has + * been removed and then complete eviction of the objset. + */ + if (!DMU_OBJECT_IS_SPECIAL(object)) + list_insert_head(&os->os_dnodes, dn); + membar_producer(); + + /* + * Everything else must be valid before assigning dn_objset + * makes the dnode eligible for dnode_move(). + */ + dn->dn_objset = os; + + dnh->dnh_dnode = dn; + mutex_exit(&os->os_lock); + + arc_space_consume(sizeof (dnode_t), ARC_SPACE_OTHER); + return (dn); +} + +/* + * Caller must be holding the dnode handle, which is released upon return. + */ +static void +dnode_destroy(dnode_t *dn) +{ + objset_t *os = dn->dn_objset; + boolean_t complete_os_eviction = B_FALSE; + + ASSERT((dn->dn_id_flags & DN_ID_NEW_EXIST) == 0); + + mutex_enter(&os->os_lock); + POINTER_INVALIDATE(&dn->dn_objset); + if (!DMU_OBJECT_IS_SPECIAL(dn->dn_object)) { + list_remove(&os->os_dnodes, dn); + complete_os_eviction = + list_is_empty(&os->os_dnodes) && + list_link_active(&os->os_evicting_node); + } + mutex_exit(&os->os_lock); + + /* the dnode can no longer move, so we can release the handle */ + zrl_remove(&dn->dn_handle->dnh_zrlock); + + dn->dn_allocated_txg = 0; + dn->dn_free_txg = 0; + dn->dn_assigned_txg = 0; + + dn->dn_dirtyctx = 0; + if (dn->dn_dirtyctx_firstset != NULL) { + kmem_free(dn->dn_dirtyctx_firstset, 1); + dn->dn_dirtyctx_firstset = NULL; + } + if (dn->dn_bonus != NULL) { + mutex_enter(&dn->dn_bonus->db_mtx); + dbuf_destroy(dn->dn_bonus); + dn->dn_bonus = NULL; + } + dn->dn_zio = NULL; + + dn->dn_have_spill = B_FALSE; + dn->dn_oldused = 0; + dn->dn_oldflags = 0; + dn->dn_olduid = 0; + dn->dn_oldgid = 0; + dn->dn_newuid = 0; + dn->dn_newgid = 0; + dn->dn_id_flags = 0; + + dmu_zfetch_fini(&dn->dn_zfetch); + kmem_cache_free(dnode_cache, dn); + arc_space_return(sizeof (dnode_t), ARC_SPACE_OTHER); + + if (complete_os_eviction) + dmu_objset_evict_done(os); +} + +void +dnode_allocate(dnode_t *dn, dmu_object_type_t ot, int blocksize, int ibs, + dmu_object_type_t bonustype, int bonuslen, dmu_tx_t *tx) +{ + int i; + + ASSERT3U(blocksize, <=, + spa_maxblocksize(dmu_objset_spa(dn->dn_objset))); + if (blocksize == 0) + blocksize = 1 << zfs_default_bs; + else + blocksize = P2ROUNDUP(blocksize, SPA_MINBLOCKSIZE); + + if (ibs == 0) + ibs = zfs_default_ibs; + + ibs = MIN(MAX(ibs, DN_MIN_INDBLKSHIFT), DN_MAX_INDBLKSHIFT); + + dprintf("os=%p obj=%llu txg=%llu blocksize=%d ibs=%d\n", dn->dn_objset, + dn->dn_object, tx->tx_txg, blocksize, ibs); + + ASSERT(dn->dn_type == DMU_OT_NONE); + ASSERT(bcmp(dn->dn_phys, &dnode_phys_zero, sizeof (dnode_phys_t)) == 0); + ASSERT(dn->dn_phys->dn_type == DMU_OT_NONE); + ASSERT(ot != DMU_OT_NONE); + ASSERT(DMU_OT_IS_VALID(ot)); + ASSERT((bonustype == DMU_OT_NONE && bonuslen == 0) || + (bonustype == DMU_OT_SA && bonuslen == 0) || + (bonustype != DMU_OT_NONE && bonuslen != 0)); + ASSERT(DMU_OT_IS_VALID(bonustype)); + ASSERT3U(bonuslen, <=, DN_MAX_BONUSLEN); + ASSERT(dn->dn_type == DMU_OT_NONE); + ASSERT0(dn->dn_maxblkid); + ASSERT0(dn->dn_allocated_txg); + ASSERT0(dn->dn_assigned_txg); + ASSERT(refcount_is_zero(&dn->dn_tx_holds)); + ASSERT3U(refcount_count(&dn->dn_holds), <=, 1); + ASSERT(avl_is_empty(&dn->dn_dbufs)); + + for (i = 0; i < TXG_SIZE; i++) { + ASSERT0(dn->dn_next_nblkptr[i]); + ASSERT0(dn->dn_next_nlevels[i]); + ASSERT0(dn->dn_next_indblkshift[i]); + ASSERT0(dn->dn_next_bonuslen[i]); + ASSERT0(dn->dn_next_bonustype[i]); + ASSERT0(dn->dn_rm_spillblk[i]); + ASSERT0(dn->dn_next_blksz[i]); + ASSERT(!list_link_active(&dn->dn_dirty_link[i])); + ASSERT3P(list_head(&dn->dn_dirty_records[i]), ==, NULL); + ASSERT3P(dn->dn_free_ranges[i], ==, NULL); + } + + dn->dn_type = ot; + dnode_setdblksz(dn, blocksize); + dn->dn_indblkshift = ibs; + dn->dn_nlevels = 1; + if (bonustype == DMU_OT_SA) /* Maximize bonus space for SA */ + dn->dn_nblkptr = 1; + else + dn->dn_nblkptr = 1 + + ((DN_MAX_BONUSLEN - bonuslen) >> SPA_BLKPTRSHIFT); + dn->dn_bonustype = bonustype; + dn->dn_bonuslen = bonuslen; + dn->dn_checksum = ZIO_CHECKSUM_INHERIT; + dn->dn_compress = ZIO_COMPRESS_INHERIT; + dn->dn_dirtyctx = 0; + + dn->dn_free_txg = 0; + if (dn->dn_dirtyctx_firstset) { + kmem_free(dn->dn_dirtyctx_firstset, 1); + dn->dn_dirtyctx_firstset = NULL; + } + + dn->dn_allocated_txg = tx->tx_txg; + dn->dn_id_flags = 0; + + 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_bonustype[tx->tx_txg & TXG_MASK] = dn->dn_bonustype; + dn->dn_next_blksz[tx->tx_txg & TXG_MASK] = dn->dn_datablksz; +} + +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 nblkptr; + + ASSERT3U(blocksize, >=, SPA_MINBLOCKSIZE); + ASSERT3U(blocksize, <=, + spa_maxblocksize(dmu_objset_spa(dn->dn_objset))); + ASSERT0(blocksize % SPA_MINBLOCKSIZE); + ASSERT(dn->dn_object != DMU_META_DNODE_OBJECT || dmu_tx_private_ok(tx)); + ASSERT(tx->tx_txg != 0); + ASSERT((bonustype == DMU_OT_NONE && bonuslen == 0) || + (bonustype != DMU_OT_NONE && bonuslen != 0) || + (bonustype == DMU_OT_SA && bonuslen == 0)); + ASSERT(DMU_OT_IS_VALID(bonustype)); + ASSERT3U(bonuslen, <=, DN_MAX_BONUSLEN); + + /* clean up any unreferenced dbufs */ + dnode_evict_dbufs(dn); + + dn->dn_id_flags = 0; + + rw_enter(&dn->dn_struct_rwlock, RW_WRITER); + dnode_setdirty(dn, tx); + if (dn->dn_datablksz != blocksize) { + /* change blocksize */ + ASSERT(dn->dn_maxblkid == 0 && + (BP_IS_HOLE(&dn->dn_phys->dn_blkptr[0]) || + dnode_block_freed(dn, 0))); + dnode_setdblksz(dn, blocksize); + dn->dn_next_blksz[tx->tx_txg&TXG_MASK] = blocksize; + } + if (dn->dn_bonuslen != bonuslen) + dn->dn_next_bonuslen[tx->tx_txg&TXG_MASK] = bonuslen; + + if (bonustype == DMU_OT_SA) /* Maximize bonus space for SA */ + nblkptr = 1; + else + nblkptr = 1 + ((DN_MAX_BONUSLEN - bonuslen) >> SPA_BLKPTRSHIFT); + if (dn->dn_bonustype != bonustype) + dn->dn_next_bonustype[tx->tx_txg&TXG_MASK] = bonustype; + if (dn->dn_nblkptr != nblkptr) + dn->dn_next_nblkptr[tx->tx_txg&TXG_MASK] = nblkptr; + if (dn->dn_phys->dn_flags & DNODE_FLAG_SPILL_BLKPTR) { + dbuf_rm_spill(dn, tx); + dnode_rm_spill(dn, tx); + } + rw_exit(&dn->dn_struct_rwlock); + + /* change type */ + dn->dn_type = ot; + + /* change bonus size and type */ + mutex_enter(&dn->dn_mtx); + dn->dn_bonustype = bonustype; + dn->dn_bonuslen = bonuslen; + dn->dn_nblkptr = nblkptr; + dn->dn_checksum = ZIO_CHECKSUM_INHERIT; + dn->dn_compress = ZIO_COMPRESS_INHERIT; + ASSERT3U(dn->dn_nblkptr, <=, DN_MAX_NBLKPTR); + + /* fix up the bonus db_size */ + if (dn->dn_bonus) { + 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); +} + +#ifdef DNODE_STATS +static struct { + uint64_t dms_dnode_invalid; + uint64_t dms_dnode_recheck1; + uint64_t dms_dnode_recheck2; + uint64_t dms_dnode_special; + uint64_t dms_dnode_handle; + uint64_t dms_dnode_rwlock; + uint64_t dms_dnode_active; +} dnode_move_stats; +#endif /* DNODE_STATS */ + +#ifdef _KERNEL +static void +dnode_move_impl(dnode_t *odn, dnode_t *ndn) +{ + int i; + + ASSERT(!RW_LOCK_HELD(&odn->dn_struct_rwlock)); + ASSERT(MUTEX_NOT_HELD(&odn->dn_mtx)); + ASSERT(MUTEX_NOT_HELD(&odn->dn_dbufs_mtx)); + ASSERT(!RW_LOCK_HELD(&odn->dn_zfetch.zf_rwlock)); + + /* Copy fields. */ + ndn->dn_objset = odn->dn_objset; + ndn->dn_object = odn->dn_object; + ndn->dn_dbuf = odn->dn_dbuf; + ndn->dn_handle = odn->dn_handle; + ndn->dn_phys = odn->dn_phys; + ndn->dn_type = odn->dn_type; + ndn->dn_bonuslen = odn->dn_bonuslen; + ndn->dn_bonustype = odn->dn_bonustype; + ndn->dn_nblkptr = odn->dn_nblkptr; + ndn->dn_checksum = odn->dn_checksum; + ndn->dn_compress = odn->dn_compress; + ndn->dn_nlevels = odn->dn_nlevels; + ndn->dn_indblkshift = odn->dn_indblkshift; + ndn->dn_datablkshift = odn->dn_datablkshift; + ndn->dn_datablkszsec = odn->dn_datablkszsec; + ndn->dn_datablksz = odn->dn_datablksz; + ndn->dn_maxblkid = odn->dn_maxblkid; + bcopy(&odn->dn_next_type[0], &ndn->dn_next_type[0], + sizeof (odn->dn_next_type)); + bcopy(&odn->dn_next_nblkptr[0], &ndn->dn_next_nblkptr[0], + sizeof (odn->dn_next_nblkptr)); + bcopy(&odn->dn_next_nlevels[0], &ndn->dn_next_nlevels[0], + sizeof (odn->dn_next_nlevels)); + bcopy(&odn->dn_next_indblkshift[0], &ndn->dn_next_indblkshift[0], + sizeof (odn->dn_next_indblkshift)); + bcopy(&odn->dn_next_bonustype[0], &ndn->dn_next_bonustype[0], + sizeof (odn->dn_next_bonustype)); + bcopy(&odn->dn_rm_spillblk[0], &ndn->dn_rm_spillblk[0], + sizeof (odn->dn_rm_spillblk)); + bcopy(&odn->dn_next_bonuslen[0], &ndn->dn_next_bonuslen[0], + sizeof (odn->dn_next_bonuslen)); + bcopy(&odn->dn_next_blksz[0], &ndn->dn_next_blksz[0], + sizeof (odn->dn_next_blksz)); + for (i = 0; i < TXG_SIZE; i++) { + list_move_tail(&ndn->dn_dirty_records[i], + &odn->dn_dirty_records[i]); + } + bcopy(&odn->dn_free_ranges[0], &ndn->dn_free_ranges[0], + sizeof (odn->dn_free_ranges)); + ndn->dn_allocated_txg = odn->dn_allocated_txg; + ndn->dn_free_txg = odn->dn_free_txg; + ndn->dn_assigned_txg = odn->dn_assigned_txg; + ndn->dn_dirtyctx = odn->dn_dirtyctx; + ndn->dn_dirtyctx_firstset = odn->dn_dirtyctx_firstset; + ASSERT(refcount_count(&odn->dn_tx_holds) == 0); + refcount_transfer(&ndn->dn_holds, &odn->dn_holds); + ASSERT(avl_is_empty(&ndn->dn_dbufs)); + avl_swap(&ndn->dn_dbufs, &odn->dn_dbufs); + ndn->dn_dbufs_count = odn->dn_dbufs_count; + ndn->dn_bonus = odn->dn_bonus; + ndn->dn_have_spill = odn->dn_have_spill; + ndn->dn_zio = odn->dn_zio; + ndn->dn_oldused = odn->dn_oldused; + ndn->dn_oldflags = odn->dn_oldflags; + ndn->dn_olduid = odn->dn_olduid; + ndn->dn_oldgid = odn->dn_oldgid; + ndn->dn_newuid = odn->dn_newuid; + ndn->dn_newgid = odn->dn_newgid; + ndn->dn_id_flags = odn->dn_id_flags; + dmu_zfetch_init(&ndn->dn_zfetch, NULL); + list_move_tail(&ndn->dn_zfetch.zf_stream, &odn->dn_zfetch.zf_stream); + ndn->dn_zfetch.zf_dnode = odn->dn_zfetch.zf_dnode; + + /* + * Update back pointers. Updating the handle fixes the back pointer of + * every descendant dbuf as well as the bonus dbuf. + */ + ASSERT(ndn->dn_handle->dnh_dnode == odn); + ndn->dn_handle->dnh_dnode = ndn; + if (ndn->dn_zfetch.zf_dnode == odn) { + ndn->dn_zfetch.zf_dnode = ndn; + } + + /* + * Invalidate the original dnode by clearing all of its back pointers. + */ + odn->dn_dbuf = NULL; + odn->dn_handle = NULL; + avl_create(&odn->dn_dbufs, dbuf_compare, sizeof (dmu_buf_impl_t), + offsetof(dmu_buf_impl_t, db_link)); + odn->dn_dbufs_count = 0; + odn->dn_bonus = NULL; + odn->dn_zfetch.zf_dnode = NULL; + + /* + * Set the low bit of the objset pointer to ensure that dnode_move() + * recognizes the dnode as invalid in any subsequent callback. + */ + POINTER_INVALIDATE(&odn->dn_objset); + + /* + * Satisfy the destructor. + */ + for (i = 0; i < TXG_SIZE; i++) { + list_create(&odn->dn_dirty_records[i], + sizeof (dbuf_dirty_record_t), + offsetof(dbuf_dirty_record_t, dr_dirty_node)); + odn->dn_free_ranges[i] = NULL; + odn->dn_next_nlevels[i] = 0; + odn->dn_next_indblkshift[i] = 0; + odn->dn_next_bonustype[i] = 0; + odn->dn_rm_spillblk[i] = 0; + odn->dn_next_bonuslen[i] = 0; + odn->dn_next_blksz[i] = 0; + } + odn->dn_allocated_txg = 0; + odn->dn_free_txg = 0; + odn->dn_assigned_txg = 0; + odn->dn_dirtyctx = 0; + odn->dn_dirtyctx_firstset = NULL; + odn->dn_have_spill = B_FALSE; + odn->dn_zio = NULL; + odn->dn_oldused = 0; + odn->dn_oldflags = 0; + odn->dn_olduid = 0; + odn->dn_oldgid = 0; + odn->dn_newuid = 0; + odn->dn_newgid = 0; + odn->dn_id_flags = 0; + + /* + * Mark the dnode. + */ + ndn->dn_moved = 1; + odn->dn_moved = (uint8_t)-1; +} + +#ifdef illumos +/*ARGSUSED*/ +static kmem_cbrc_t +dnode_move(void *buf, void *newbuf, size_t size, void *arg) +{ + dnode_t *odn = buf, *ndn = newbuf; + objset_t *os; + int64_t refcount; + uint32_t dbufs; + + /* + * The dnode is on the objset's list of known dnodes if the objset + * pointer is valid. We set the low bit of the objset pointer when + * freeing the dnode to invalidate it, and the memory patterns written + * by kmem (baddcafe and deadbeef) set at least one of the two low bits. + * A newly created dnode sets the objset pointer last of all to indicate + * that the dnode is known and in a valid state to be moved by this + * function. + */ + os = odn->dn_objset; + if (!POINTER_IS_VALID(os)) { + DNODE_STAT_ADD(dnode_move_stats.dms_dnode_invalid); + return (KMEM_CBRC_DONT_KNOW); + } + + /* + * Ensure that the objset does not go away during the move. + */ + rw_enter(&os_lock, RW_WRITER); + if (os != odn->dn_objset) { + rw_exit(&os_lock); + DNODE_STAT_ADD(dnode_move_stats.dms_dnode_recheck1); + return (KMEM_CBRC_DONT_KNOW); + } + + /* + * If the dnode is still valid, then so is the objset. We know that no + * valid objset can be freed while we hold os_lock, so we can safely + * ensure that the objset remains in use. + */ + mutex_enter(&os->os_lock); + + /* + * Recheck the objset pointer in case the dnode was removed just before + * acquiring the lock. + */ + if (os != odn->dn_objset) { + mutex_exit(&os->os_lock); + rw_exit(&os_lock); + DNODE_STAT_ADD(dnode_move_stats.dms_dnode_recheck2); + return (KMEM_CBRC_DONT_KNOW); + } + + /* + * At this point we know that as long as we hold os->os_lock, the dnode + * cannot be freed and fields within the dnode can be safely accessed. + * The objset listing this dnode cannot go away as long as this dnode is + * on its list. + */ + rw_exit(&os_lock); + if (DMU_OBJECT_IS_SPECIAL(odn->dn_object)) { + mutex_exit(&os->os_lock); + DNODE_STAT_ADD(dnode_move_stats.dms_dnode_special); + return (KMEM_CBRC_NO); + } + ASSERT(odn->dn_dbuf != NULL); /* only "special" dnodes have no parent */ + + /* + * Lock the dnode handle to prevent the dnode from obtaining any new + * holds. This also prevents the descendant dbufs and the bonus dbuf + * from accessing the dnode, so that we can discount their holds. The + * handle is safe to access because we know that while the dnode cannot + * go away, neither can its handle. Once we hold dnh_zrlock, we can + * safely move any dnode referenced only by dbufs. + */ + if (!zrl_tryenter(&odn->dn_handle->dnh_zrlock)) { + mutex_exit(&os->os_lock); + DNODE_STAT_ADD(dnode_move_stats.dms_dnode_handle); + return (KMEM_CBRC_LATER); + } + + /* + * Ensure a consistent view of the dnode's holds and the dnode's dbufs. + * We need to guarantee that there is a hold for every dbuf in order to + * determine whether the dnode is actively referenced. Falsely matching + * a dbuf to an active hold would lead to an unsafe move. It's possible + * that a thread already having an active dnode hold is about to add a + * dbuf, and we can't compare hold and dbuf counts while the add is in + * progress. + */ + if (!rw_tryenter(&odn->dn_struct_rwlock, RW_WRITER)) { + zrl_exit(&odn->dn_handle->dnh_zrlock); + mutex_exit(&os->os_lock); + DNODE_STAT_ADD(dnode_move_stats.dms_dnode_rwlock); + return (KMEM_CBRC_LATER); + } + + /* + * A dbuf may be removed (evicted) without an active dnode hold. In that + * case, the dbuf count is decremented under the handle lock before the + * dbuf's hold is released. This order ensures that if we count the hold + * after the dbuf is removed but before its hold is released, we will + * treat the unmatched hold as active and exit safely. If we count the + * hold before the dbuf is removed, the hold is discounted, and the + * removal is blocked until the move completes. + */ + refcount = refcount_count(&odn->dn_holds); + ASSERT(refcount >= 0); + dbufs = odn->dn_dbufs_count; + + /* We can't have more dbufs than dnode holds. */ + ASSERT3U(dbufs, <=, refcount); + DTRACE_PROBE3(dnode__move, dnode_t *, odn, int64_t, refcount, + uint32_t, dbufs); + + if (refcount > dbufs) { + rw_exit(&odn->dn_struct_rwlock); + zrl_exit(&odn->dn_handle->dnh_zrlock); + mutex_exit(&os->os_lock); + DNODE_STAT_ADD(dnode_move_stats.dms_dnode_active); + return (KMEM_CBRC_LATER); + } + + rw_exit(&odn->dn_struct_rwlock); + + /* + * At this point we know that anyone with a hold on the dnode is not + * actively referencing it. The dnode is known and in a valid state to + * move. We're holding the locks needed to execute the critical section. + */ + dnode_move_impl(odn, ndn); + + list_link_replace(&odn->dn_link, &ndn->dn_link); + /* If the dnode was safe to move, the refcount cannot have changed. */ + ASSERT(refcount == refcount_count(&ndn->dn_holds)); + ASSERT(dbufs == ndn->dn_dbufs_count); + zrl_exit(&ndn->dn_handle->dnh_zrlock); /* handle has moved */ + mutex_exit(&os->os_lock); + + return (KMEM_CBRC_YES); +} +#endif /* illumos */ +#endif /* _KERNEL */ + +void +dnode_special_close(dnode_handle_t *dnh) +{ + dnode_t *dn = dnh->dnh_dnode; + + /* + * Wait for final references to the dnode to clear. This can + * only happen if the arc is asyncronously evicting state that + * has a hold on this dnode while we are trying to evict this + * dnode. + */ + while (refcount_count(&dn->dn_holds) > 0) + delay(1); + ASSERT(dn->dn_dbuf == NULL || + dmu_buf_get_user(&dn->dn_dbuf->db) == NULL); + zrl_add(&dnh->dnh_zrlock); + dnode_destroy(dn); /* implicit zrl_remove() */ + zrl_destroy(&dnh->dnh_zrlock); + dnh->dnh_dnode = NULL; +} + +void +dnode_special_open(objset_t *os, dnode_phys_t *dnp, uint64_t object, + dnode_handle_t *dnh) +{ + dnode_t *dn; + + dn = dnode_create(os, dnp, NULL, object, dnh); + zrl_init(&dnh->dnh_zrlock); + DNODE_VERIFY(dn); +} + +static void +dnode_buf_evict_async(void *dbu) +{ + dnode_children_t *children_dnodes = dbu; + int i; + + for (i = 0; i < children_dnodes->dnc_count; i++) { + dnode_handle_t *dnh = &children_dnodes->dnc_children[i]; + dnode_t *dn; + + /* + * The dnode handle lock guards against the dnode moving to + * another valid address, so there is no need here to guard + * against changes to or from NULL. + */ + if (dnh->dnh_dnode == NULL) { + zrl_destroy(&dnh->dnh_zrlock); + continue; + } + + zrl_add(&dnh->dnh_zrlock); + dn = dnh->dnh_dnode; + /* + * If there are holds on this dnode, then there should + * be holds on the dnode's containing dbuf as well; thus + * it wouldn't be eligible for eviction and this function + * would not have been called. + */ + ASSERT(refcount_is_zero(&dn->dn_holds)); + ASSERT(refcount_is_zero(&dn->dn_tx_holds)); + + dnode_destroy(dn); /* implicit zrl_remove() */ + zrl_destroy(&dnh->dnh_zrlock); + dnh->dnh_dnode = NULL; + } + kmem_free(children_dnodes, sizeof (dnode_children_t) + + children_dnodes->dnc_count * sizeof (dnode_handle_t)); +} + +/* + * errors: + * EINVAL - invalid object number. + * EIO - i/o error. + * succeeds even for free dnodes. + */ +int +dnode_hold_impl(objset_t *os, uint64_t object, int flag, + void *tag, dnode_t **dnp) +{ + int epb, idx, err; + int drop_struct_lock = FALSE; + int type; + uint64_t blk; + dnode_t *mdn, *dn; + dmu_buf_impl_t *db; + dnode_children_t *children_dnodes; + dnode_handle_t *dnh; + + /* + * If you are holding the spa config lock as writer, you shouldn't + * be asking the DMU to do *anything* unless it's the root pool + * which may require us to read from the root filesystem while + * holding some (not all) of the locks as writer. + */ + ASSERT(spa_config_held(os->os_spa, SCL_ALL, RW_WRITER) == 0 || + (spa_is_root(os->os_spa) && + spa_config_held(os->os_spa, SCL_STATE, RW_WRITER))); + + ASSERT((flag & DNODE_MUST_BE_ALLOCATED) || (flag & DNODE_MUST_BE_FREE)); + + if (object == DMU_USERUSED_OBJECT || object == DMU_GROUPUSED_OBJECT) { + dn = (object == DMU_USERUSED_OBJECT) ? + DMU_USERUSED_DNODE(os) : DMU_GROUPUSED_DNODE(os); + if (dn == NULL) + return (SET_ERROR(ENOENT)); + type = dn->dn_type; + if ((flag & DNODE_MUST_BE_ALLOCATED) && type == DMU_OT_NONE) + return (SET_ERROR(ENOENT)); + if ((flag & DNODE_MUST_BE_FREE) && type != DMU_OT_NONE) + return (SET_ERROR(EEXIST)); + DNODE_VERIFY(dn); + (void) refcount_add(&dn->dn_holds, tag); + *dnp = dn; + return (0); + } + + if (object == 0 || object >= DN_MAX_OBJECT) + return (SET_ERROR(EINVAL)); + + mdn = DMU_META_DNODE(os); + ASSERT(mdn->dn_object == DMU_META_DNODE_OBJECT); + + DNODE_VERIFY(mdn); + + if (!RW_WRITE_HELD(&mdn->dn_struct_rwlock)) { + rw_enter(&mdn->dn_struct_rwlock, RW_READER); + drop_struct_lock = TRUE; + } + + blk = dbuf_whichblock(mdn, 0, object * sizeof (dnode_phys_t)); + + db = dbuf_hold(mdn, blk, FTAG); + if (drop_struct_lock) + rw_exit(&mdn->dn_struct_rwlock); + if (db == NULL) + return (SET_ERROR(EIO)); + err = dbuf_read(db, NULL, DB_RF_CANFAIL); + if (err) { + dbuf_rele(db, FTAG); + return (err); + } + + ASSERT3U(db->db.db_size, >=, 1<<DNODE_SHIFT); + epb = db->db.db_size >> DNODE_SHIFT; + + idx = object & (epb-1); + + ASSERT(DB_DNODE(db)->dn_type == DMU_OT_DNODE); + children_dnodes = dmu_buf_get_user(&db->db); + if (children_dnodes == NULL) { + int i; + dnode_children_t *winner; + children_dnodes = kmem_zalloc(sizeof (dnode_children_t) + + epb * sizeof (dnode_handle_t), KM_SLEEP); + children_dnodes->dnc_count = epb; + dnh = &children_dnodes->dnc_children[0]; + for (i = 0; i < epb; i++) { + zrl_init(&dnh[i].dnh_zrlock); + } + dmu_buf_init_user(&children_dnodes->dnc_dbu, NULL, + dnode_buf_evict_async, NULL); + winner = dmu_buf_set_user(&db->db, &children_dnodes->dnc_dbu); + if (winner != NULL) { + + for (i = 0; i < epb; i++) { + zrl_destroy(&dnh[i].dnh_zrlock); + } + + kmem_free(children_dnodes, sizeof (dnode_children_t) + + epb * sizeof (dnode_handle_t)); + children_dnodes = winner; + } + } + ASSERT(children_dnodes->dnc_count == epb); + + dnh = &children_dnodes->dnc_children[idx]; + zrl_add(&dnh->dnh_zrlock); + dn = dnh->dnh_dnode; + if (dn == NULL) { + dnode_phys_t *phys = (dnode_phys_t *)db->db.db_data+idx; + + dn = dnode_create(os, phys, db, object, dnh); + } + + mutex_enter(&dn->dn_mtx); + type = dn->dn_type; + if (dn->dn_free_txg || + ((flag & DNODE_MUST_BE_ALLOCATED) && type == DMU_OT_NONE) || + ((flag & DNODE_MUST_BE_FREE) && + (type != DMU_OT_NONE || !refcount_is_zero(&dn->dn_holds)))) { + mutex_exit(&dn->dn_mtx); + zrl_remove(&dnh->dnh_zrlock); + dbuf_rele(db, FTAG); + return ((flag & DNODE_MUST_BE_ALLOCATED) ? ENOENT : EEXIST); + } + if (refcount_add(&dn->dn_holds, tag) == 1) + dbuf_add_ref(db, dnh); + mutex_exit(&dn->dn_mtx); + + /* Now we can rely on the hold to prevent the dnode from moving. */ + zrl_remove(&dnh->dnh_zrlock); + + DNODE_VERIFY(dn); + ASSERT3P(dn->dn_dbuf, ==, db); + ASSERT3U(dn->dn_object, ==, object); + dbuf_rele(db, FTAG); + + *dnp = dn; + return (0); +} + +/* + * Return held dnode if the object is allocated, NULL if not. + */ +int +dnode_hold(objset_t *os, uint64_t object, void *tag, dnode_t **dnp) +{ + return (dnode_hold_impl(os, object, DNODE_MUST_BE_ALLOCATED, tag, dnp)); +} + +/* + * 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) +{ + 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 +dnode_rele(dnode_t *dn, void *tag) +{ + mutex_enter(&dn->dn_mtx); + dnode_rele_and_unlock(dn, tag, B_FALSE); +} + +void +dnode_rele_and_unlock(dnode_t *dn, void *tag, boolean_t evicting) +{ + uint64_t refs; + /* Get while the hold prevents the dnode from moving. */ + dmu_buf_impl_t *db = dn->dn_dbuf; + dnode_handle_t *dnh = dn->dn_handle; + + refs = refcount_remove(&dn->dn_holds, tag); + mutex_exit(&dn->dn_mtx); + + /* + * It's unsafe to release the last hold on a dnode by dnode_rele() or + * indirectly by dbuf_rele() while relying on the dnode handle to + * prevent the dnode from moving, since releasing the last hold could + * result in the dnode's parent dbuf evicting its dnode handles. For + * that reason anyone calling dnode_rele() or dbuf_rele() without some + * other direct or indirect hold on the dnode must first drop the dnode + * handle. + */ + ASSERT(refs > 0 || dnh->dnh_zrlock.zr_owner != curthread); + + /* NOTE: the DNODE_DNODE does not have a dn_dbuf */ + if (refs == 0 && db != NULL) { + /* + * Another thread could add a hold to the dnode handle in + * dnode_hold_impl() while holding the parent dbuf. Since the + * hold on the parent dbuf prevents the handle from being + * destroyed, the hold on the handle is OK. We can't yet assert + * that the handle has zero references, but that will be + * asserted anyway when the handle gets destroyed. + */ + mutex_enter(&db->db_mtx); + dbuf_rele_and_unlock(db, dnh, evicting); + } +} + +void +dnode_setdirty(dnode_t *dn, dmu_tx_t *tx) +{ + objset_t *os = dn->dn_objset; + uint64_t txg = tx->tx_txg; + + if (DMU_OBJECT_IS_SPECIAL(dn->dn_object)) { + dsl_dataset_dirty(os->os_dsl_dataset, tx); + return; + } + + DNODE_VERIFY(dn); + +#ifdef ZFS_DEBUG + mutex_enter(&dn->dn_mtx); + ASSERT(dn->dn_phys->dn_type || dn->dn_allocated_txg); + ASSERT(dn->dn_free_txg == 0 || dn->dn_free_txg >= txg); + mutex_exit(&dn->dn_mtx); +#endif + + /* + * Determine old uid/gid when necessary + */ + dmu_objset_userquota_get_ids(dn, B_TRUE, tx); + + multilist_t *dirtylist = os->os_dirty_dnodes[txg & TXG_MASK]; + multilist_sublist_t *mls = multilist_sublist_lock_obj(dirtylist, dn); + + /* + * If we are already marked dirty, we're done. + */ + if (list_link_active(&dn->dn_dirty_link[txg & TXG_MASK])) { + multilist_sublist_unlock(mls); + return; + } + + ASSERT(!refcount_is_zero(&dn->dn_holds) || + !avl_is_empty(&dn->dn_dbufs)); + ASSERT(dn->dn_datablksz != 0); + ASSERT0(dn->dn_next_bonuslen[txg&TXG_MASK]); + ASSERT0(dn->dn_next_blksz[txg&TXG_MASK]); + ASSERT0(dn->dn_next_bonustype[txg&TXG_MASK]); + + dprintf_ds(os->os_dsl_dataset, "obj=%llu txg=%llu\n", + dn->dn_object, txg); + + multilist_sublist_insert_head(mls, dn); + + multilist_sublist_unlock(mls); + + /* + * The dnode maintains a hold on its containing dbuf as + * long as there are holds on it. Each instantiated child + * dbuf maintains a hold on the dnode. When the last child + * drops its hold, the dnode will drop its hold on the + * containing dbuf. We add a "dirty hold" here so that the + * dnode will hang around after we finish processing its + * children. + */ + VERIFY(dnode_add_ref(dn, (void *)(uintptr_t)tx->tx_txg)); + + (void) dbuf_dirty(dn->dn_dbuf, tx); + + dsl_dataset_dirty(os->os_dsl_dataset, tx); +} + +void +dnode_free(dnode_t *dn, dmu_tx_t *tx) +{ + mutex_enter(&dn->dn_mtx); + if (dn->dn_type == DMU_OT_NONE || dn->dn_free_txg) { + mutex_exit(&dn->dn_mtx); + return; + } + dn->dn_free_txg = tx->tx_txg; + mutex_exit(&dn->dn_mtx); + + dnode_setdirty(dn, tx); +} + +/* + * Try to change the block size for the indicated dnode. This can only + * succeed if there are no blocks allocated or dirty beyond first block + */ +int +dnode_set_blksz(dnode_t *dn, uint64_t size, int ibs, dmu_tx_t *tx) +{ + dmu_buf_impl_t *db; + int err; + + ASSERT3U(size, <=, spa_maxblocksize(dmu_objset_spa(dn->dn_objset))); + if (size == 0) + size = SPA_MINBLOCKSIZE; + else + size = P2ROUNDUP(size, SPA_MINBLOCKSIZE); + + if (ibs == dn->dn_indblkshift) + ibs = 0; + + if (size >> SPA_MINBLOCKSHIFT == dn->dn_datablkszsec && ibs == 0) + return (0); + + rw_enter(&dn->dn_struct_rwlock, RW_WRITER); + + /* Check for any allocated blocks beyond the first */ + if (dn->dn_maxblkid != 0) + goto fail; + + mutex_enter(&dn->dn_dbufs_mtx); + for (db = avl_first(&dn->dn_dbufs); db != NULL; + db = AVL_NEXT(&dn->dn_dbufs, db)) { + if (db->db_blkid != 0 && db->db_blkid != DMU_BONUS_BLKID && + db->db_blkid != DMU_SPILL_BLKID) { + mutex_exit(&dn->dn_dbufs_mtx); + goto fail; + } + } + mutex_exit(&dn->dn_dbufs_mtx); + + if (ibs && dn->dn_nlevels != 1) + goto fail; + + /* resize the old block */ + err = dbuf_hold_impl(dn, 0, 0, TRUE, FALSE, 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); + dn->dn_next_blksz[tx->tx_txg&TXG_MASK] = size; + if (ibs) { + 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); + + rw_exit(&dn->dn_struct_rwlock); + return (0); + +fail: + rw_exit(&dn->dn_struct_rwlock); + return (SET_ERROR(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, boolean_t have_read) +{ + uint64_t txgoff = tx->tx_txg & TXG_MASK; + int epbs, new_nlevels; + uint64_t sz; + + ASSERT(blkid != DMU_BONUS_BLKID); + + 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) + goto out; + + dn->dn_maxblkid = blkid; + + /* + * Compute the number of levels necessary to support the new maxblkid. + */ + new_nlevels = 1; + epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT; + for (sz = dn->dn_nblkptr; + sz <= blkid && sz >= dn->dn_nblkptr; sz <<= epbs) + new_nlevels++; + + if (new_nlevels > dn->dn_nlevels) { + int old_nlevels = dn->dn_nlevels; + dmu_buf_impl_t *db; + list_t *list; + dbuf_dirty_record_t *new, *dr, *dr_next; + + dn->dn_nlevels = new_nlevels; + + ASSERT3U(new_nlevels, >, dn->dn_next_nlevels[txgoff]); + dn->dn_next_nlevels[txgoff] = new_nlevels; + + /* dirty the left indirects */ + db = dbuf_hold_level(dn, old_nlevels, 0, FTAG); + ASSERT(db != NULL); + new = dbuf_dirty(db, tx); + dbuf_rele(db, FTAG); + + /* transfer the dirty records to the new indirect */ + mutex_enter(&dn->dn_mtx); + mutex_enter(&new->dt.di.dr_mtx); + list = &dn->dn_dirty_records[txgoff]; + for (dr = list_head(list); dr; dr = dr_next) { + dr_next = list_next(&dn->dn_dirty_records[txgoff], dr); + if (dr->dr_dbuf->db_level != new_nlevels-1 && + dr->dr_dbuf->db_blkid != DMU_BONUS_BLKID && + dr->dr_dbuf->db_blkid != DMU_SPILL_BLKID) { + ASSERT(dr->dr_dbuf->db_level == old_nlevels-1); + list_remove(&dn->dn_dirty_records[txgoff], dr); + list_insert_tail(&new->dt.di.dr_children, dr); + dr->dr_parent = new; + } + } + mutex_exit(&new->dt.di.dr_mtx); + mutex_exit(&dn->dn_mtx); + } + +out: + if (have_read) + rw_downgrade(&dn->dn_struct_rwlock); +} + +static void +dnode_dirty_l1(dnode_t *dn, uint64_t l1blkid, dmu_tx_t *tx) +{ + dmu_buf_impl_t *db = dbuf_hold_level(dn, 1, l1blkid, FTAG); + if (db != NULL) { + dmu_buf_will_dirty(&db->db, tx); + dbuf_rele(db, FTAG); + } +} + +/* + * Dirty all the in-core level-1 dbufs in the range specified by start_blkid + * and end_blkid. + */ +static void +dnode_dirty_l1range(dnode_t *dn, uint64_t start_blkid, uint64_t end_blkid, + dmu_tx_t *tx) +{ + dmu_buf_impl_t db_search; + dmu_buf_impl_t *db; + avl_index_t where; + + mutex_enter(&dn->dn_dbufs_mtx); + + db_search.db_level = 1; + db_search.db_blkid = start_blkid + 1; + db_search.db_state = DB_SEARCH; + for (;;) { + + db = avl_find(&dn->dn_dbufs, &db_search, &where); + if (db == NULL) + db = avl_nearest(&dn->dn_dbufs, where, AVL_AFTER); + + if (db == NULL || db->db_level != 1 || + db->db_blkid >= end_blkid) { + break; + } + + /* + * Setup the next blkid we want to search for. + */ + db_search.db_blkid = db->db_blkid + 1; + ASSERT3U(db->db_blkid, >=, start_blkid); + + /* + * If the dbuf transitions to DB_EVICTING while we're trying + * to dirty it, then we will be unable to discover it in + * the dbuf hash table. This will result in a call to + * dbuf_create() which needs to acquire the dn_dbufs_mtx + * lock. To avoid a deadlock, we drop the lock before + * dirtying the level-1 dbuf. + */ + mutex_exit(&dn->dn_dbufs_mtx); + dnode_dirty_l1(dn, db->db_blkid, tx); + mutex_enter(&dn->dn_dbufs_mtx); + } + +#ifdef ZFS_DEBUG + /* + * Walk all the in-core level-1 dbufs and verify they have been dirtied. + */ + db_search.db_level = 1; + db_search.db_blkid = start_blkid + 1; + db_search.db_state = DB_SEARCH; + db = avl_find(&dn->dn_dbufs, &db_search, &where); + if (db == NULL) + db = avl_nearest(&dn->dn_dbufs, where, AVL_AFTER); + for (; db != NULL; db = AVL_NEXT(&dn->dn_dbufs, db)) { + if (db->db_level != 1 || db->db_blkid >= end_blkid) + break; + ASSERT(db->db_dirtycnt > 0); + } +#endif + mutex_exit(&dn->dn_dbufs_mtx); +} + +void +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, 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 (len == DMU_OBJECT_END) { + len = UINT64_MAX - off; + trunc = TRUE; + } + + /* + * First, block align the region to free: + */ + 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; fast-track this request. + */ + blkid = 0; + nblks = 1; + if (dn->dn_nlevels > 1) + dnode_dirty_l1(dn, 0, tx); + goto done; + } else if (off >= blksz) { + /* Freeing past end-of-data */ + goto out; + } else { + /* Freeing part of the block. */ + head = blksz - off; + ASSERT3U(head, >, 0); + } + blkoff = off; + } + /* zero out any partial block data at the start of the range */ + if (head) { + ASSERT3U(blkoff + head, ==, blksz); + if (len < head) + head = len; + if (dbuf_hold_impl(dn, 0, dbuf_whichblock(dn, 0, off), + TRUE, FALSE, FTAG, &db) == 0) { + caddr_t data; + + /* don't dirty if it isn't on disk and isn't dirty */ + if (db->db_last_dirty || + (db->db_blkptr && !BP_IS_HOLE(db->db_blkptr))) { + rw_exit(&dn->dn_struct_rwlock); + dmu_buf_will_dirty(&db->db, tx); + rw_enter(&dn->dn_struct_rwlock, RW_WRITER); + data = db->db.db_data; + bzero(data + blkoff, head); + } + dbuf_rele(db, FTAG); + } + off += head; + len -= head; + } + + /* If the range was less than one block, we're done */ + if (len == 0) + goto out; + + /* If the remaining range is past end of file, we're done */ + if ((off >> blkshift) > dn->dn_maxblkid) + goto out; + + ASSERT(ISP2(blksz)); + if (trunc) + tail = 0; + else + tail = P2PHASE(len, blksz); + + ASSERT0(P2PHASE(off, blksz)); + /* 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, 0, off+len), + TRUE, FALSE, 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); + dmu_buf_will_dirty(&db->db, tx); + rw_enter(&dn->dn_struct_rwlock, RW_WRITER); + bzero(db->db.db_data, tail); + } + dbuf_rele(db, FTAG); + } + len -= tail; + } + + /* 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; + + /* + * Dirty all the indirect blocks in this range. Note that only + * the first and last indirect blocks can actually be written + * (if they were partially freed) -- they must be dirtied, even if + * they do not exist on disk yet. The interior blocks will + * be freed by free_children(), so they will not actually be written. + * Even though these interior blocks will not be written, we + * dirty them for two reasons: + * + * - It ensures that the indirect blocks remain in memory until + * syncing context. (They have already been prefetched by + * dmu_tx_hold_free(), so we don't have to worry about reading + * them serially here.) + * + * - The dirty space accounting will put pressure on the txg sync + * mechanism to begin syncing, and to delay transactions if there + * is a large amount of freeing. Even though these indirect + * blocks will not be written, we could need to write the same + * amount of space if we copy the freed BPs into deadlists. + */ + if (dn->dn_nlevels > 1) { + uint64_t first, last; + + first = blkid >> epbs; + dnode_dirty_l1(dn, first, tx); + if (trunc) + last = dn->dn_maxblkid >> epbs; + else + last = (blkid + nblks - 1) >> epbs; + if (last != first) + dnode_dirty_l1(dn, last, tx); + + dnode_dirty_l1range(dn, first, last, tx); + + int shift = dn->dn_datablkshift + dn->dn_indblkshift - + SPA_BLKPTRSHIFT; + for (uint64_t i = first + 1; i < last; i++) { + /* + * Set i to the blockid of the next non-hole + * level-1 indirect block at or after i. Note + * that dnode_next_offset() operates in terms of + * level-0-equivalent bytes. + */ + uint64_t ibyte = i << shift; + int err = dnode_next_offset(dn, DNODE_FIND_HAVELOCK, + &ibyte, 2, 1, 0); + i = ibyte >> shift; + if (i >= last) + break; + + /* + * Normally we should not see an error, either + * from dnode_next_offset() or dbuf_hold_level() + * (except for ESRCH from dnode_next_offset). + * If there is an i/o error, then when we read + * this block in syncing context, it will use + * ZIO_FLAG_MUSTSUCCEED, and thus hang/panic according + * to the "failmode" property. dnode_next_offset() + * doesn't have a flag to indicate MUSTSUCCEED. + */ + if (err != 0) + break; + + dnode_dirty_l1(dn, i, tx); + } + } + +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); + int txgoff = tx->tx_txg & TXG_MASK; + if (dn->dn_free_ranges[txgoff] == NULL) { + dn->dn_free_ranges[txgoff] = range_tree_create(NULL, NULL); + } + range_tree_clear(dn->dn_free_ranges[txgoff], blkid, nblks); + range_tree_add(dn->dn_free_ranges[txgoff], blkid, nblks); + dprintf_dnode(dn, "blkid=%llu nblks=%llu txg=%llu\n", + blkid, nblks, tx->tx_txg); + mutex_exit(&dn->dn_mtx); + + dbuf_free_range(dn, blkid, blkid + nblks - 1, tx); + dnode_setdirty(dn, tx); +out: + + rw_exit(&dn->dn_struct_rwlock); +} + +static boolean_t +dnode_spill_freed(dnode_t *dn) +{ + int i; + + mutex_enter(&dn->dn_mtx); + for (i = 0; i < TXG_SIZE; i++) { + if (dn->dn_rm_spillblk[i] == DN_KILL_SPILLBLK) + break; + } + mutex_exit(&dn->dn_mtx); + return (i < TXG_SIZE); +} + +/* return TRUE if this blkid was freed in a recent txg, or FALSE if it wasn't */ +uint64_t +dnode_block_freed(dnode_t *dn, uint64_t blkid) +{ + void *dp = spa_get_dsl(dn->dn_objset->os_spa); + int i; + + if (blkid == DMU_BONUS_BLKID) + return (FALSE); + + /* + * If we're in the process of opening the pool, dp will not be + * set yet, but there shouldn't be anything dirty. + */ + if (dp == NULL) + return (FALSE); + + if (dn->dn_free_txg) + return (TRUE); + + if (blkid == DMU_SPILL_BLKID) + return (dnode_spill_freed(dn)); + + mutex_enter(&dn->dn_mtx); + for (i = 0; i < TXG_SIZE; i++) { + if (dn->dn_free_ranges[i] != NULL && + range_tree_contains(dn->dn_free_ranges[i], blkid, 1)) + break; + } + mutex_exit(&dn->dn_mtx); + return (i < TXG_SIZE); +} + +/* call from syncing context when we actually write/free space for this dnode */ +void +dnode_diduse_space(dnode_t *dn, int64_t delta) +{ + uint64_t space; + dprintf_dnode(dn, "dn=%p dnp=%p used=%llu delta=%lld\n", + dn, dn->dn_phys, + (u_longlong_t)dn->dn_phys->dn_used, + (longlong_t)delta); + + mutex_enter(&dn->dn_mtx); + space = DN_USED_BYTES(dn->dn_phys); + if (delta > 0) { + ASSERT3U(space + delta, >=, space); /* no overflow */ + } else { + ASSERT3U(space, >=, -delta); /* no underflow */ + } + space += delta; + if (spa_version(dn->dn_objset->os_spa) < SPA_VERSION_DNODE_BYTES) { + ASSERT((dn->dn_phys->dn_flags & DNODE_FLAG_USED_BYTES) == 0); + ASSERT0(P2PHASE(space, 1<<DEV_BSHIFT)); + dn->dn_phys->dn_used = space >> DEV_BSHIFT; + } else { + dn->dn_phys->dn_used = space; + dn->dn_phys->dn_flags |= DNODE_FLAG_USED_BYTES; + } + mutex_exit(&dn->dn_mtx); +} + +/* + * Scans a block at the indicated "level" looking for a hole or data, + * depending on 'flags'. + * + * If level > 0, then we are scanning an indirect block looking at its + * pointers. If level == 0, then we are looking at a block of dnodes. + * + * If we don't find what we are looking for in the block, we return ESRCH. + * Otherwise, return with *offset pointing to the beginning (if searching + * forwards) or end (if searching backwards) of the range covered by the + * block pointer we matched on (or dnode). + * + * The basic search algorithm used below by dnode_next_offset() is to + * use this function to search up the block tree (widen the search) until + * we find something (i.e., we don't return ESRCH) and then search back + * down the tree (narrow the search) until we reach our original search + * level. + */ +static int +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; + void *data = NULL; + uint64_t epbs = dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT; + uint64_t epb = 1ULL << epbs; + uint64_t minfill, maxfill; + 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) != 0); + 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; + data = dn->dn_phys->dn_blkptr; + } else { + uint64_t blkid = dbuf_whichblock(dn, lvl, *offset); + error = dbuf_hold_impl(dn, lvl, blkid, TRUE, FALSE, FTAG, &db); + if (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 (SET_ERROR(ESRCH)); + } + error = dbuf_read(db, NULL, DB_RF_CANFAIL | DB_RF_HAVESTRUCT); + if (error) { + dbuf_rele(db, FTAG); + return (error); + } + data = db->db.db_data; + } + + + if (db != NULL && txg != 0 && (db->db_blkptr == NULL || + db->db_blkptr->blk_birth <= txg || + BP_IS_HOLE(db->db_blkptr))) { + /* + * This can only happen when we are searching up the tree + * and these conditions mean that we need to keep climbing. + */ + error = SET_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 >= 0 && i < blkfill; i += inc) { + if ((dnp[i].dn_type == DMU_OT_NONE) == hole) + break; + *offset += (1ULL << span) * inc; + } + if (i < 0 || i == blkfill) + error = SET_ERROR(ESRCH); + } else { + blkptr_t *bp = data; + uint64_t start = *offset; + span = (lvl - 1) * epbs + dn->dn_datablkshift; + minfill = 0; + maxfill = blkfill << ((lvl - 1) * epbs); + + if (hole) + maxfill--; + else + minfill++; + + *offset = *offset >> span; + for (i = BF64_GET(*offset, 0, epbs); + i >= 0 && i < epb; i += inc) { + if (BP_GET_FILL(&bp[i]) >= minfill && + BP_GET_FILL(&bp[i]) <= maxfill && + (hole || bp[i].blk_birth > txg)) + break; + if (inc > 0 || *offset > 0) + *offset += inc; + } + *offset = *offset << span; + if (inc < 0) { + /* traversing backwards; position offset at the end */ + ASSERT3U(*offset, <=, start); + *offset = MIN(*offset + (1ULL << span) - 1, start); + } else if (*offset < start) { + *offset = start; + } + if (i < 0 || i >= epb) + error = SET_ERROR(ESRCH); + } + + if (db) + dbuf_rele(db, FTAG); + + return (error); +} + +/* + * Find the next hole, data, or sparse region at or after *offset. + * The value 'blkfill' tells us how many items we expect to find + * in an L0 data block; this value is 1 for normal objects, + * DNODES_PER_BLOCK for the meta dnode, and some fraction of + * DNODES_PER_BLOCK when searching for sparse regions thereof. + * + * Examples: + * + * 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, 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, 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, int flags, uint64_t *offset, + int minlvl, uint64_t blkfill, uint64_t txg) +{ + uint64_t initial_offset = *offset; + int lvl, maxlvl; + int error = 0; + + if (!(flags & DNODE_FIND_HAVELOCK)) + rw_enter(&dn->dn_struct_rwlock, RW_READER); + + if (dn->dn_phys->dn_nlevels == 0) { + error = SET_ERROR(ESRCH); + goto out; + } + + if (dn->dn_datablkshift == 0) { + if (*offset < dn->dn_datablksz) { + if (flags & DNODE_FIND_HOLE) + *offset = dn->dn_datablksz; + } else { + error = SET_ERROR(ESRCH); + } + goto out; + } + + maxlvl = dn->dn_phys->dn_nlevels; + + for (lvl = minlvl; lvl <= maxlvl; lvl++) { + error = dnode_next_offset_level(dn, + flags, offset, lvl, blkfill, txg); + if (error != ESRCH) + break; + } + + while (error == 0 && --lvl >= minlvl) { + error = dnode_next_offset_level(dn, + flags, offset, lvl, blkfill, txg); + } + + /* + * There's always a "virtual hole" at the end of the object, even + * if all BP's which physically exist are non-holes. + */ + if ((flags & DNODE_FIND_HOLE) && error == ESRCH && txg == 0 && + minlvl == 1 && blkfill == 1 && !(flags & DNODE_FIND_BACKWARDS)) { + error = 0; + } + + if (error == 0 && (flags & DNODE_FIND_BACKWARDS ? + initial_offset < *offset : initial_offset > *offset)) + error = SET_ERROR(ESRCH); +out: + if (!(flags & DNODE_FIND_HAVELOCK)) + rw_exit(&dn->dn_struct_rwlock); + + return (error); +} |