freebsd-dev/module/zfs/dnode_sync.c
Brian Behlendorf 754c6663a3 Fix dbuf eviction assertion
Replace non-fatal assertion with warning.  This was being observed
during testing and it should not be fatal.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2010-08-31 08:38:45 -07:00

698 lines
19 KiB
C

/*
* 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.
*/
#include <sys/zfs_context.h>
#include <sys/dbuf.h>
#include <sys/dnode.h>
#include <sys/dmu.h>
#include <sys/dmu_tx.h>
#include <sys/dmu_objset.h>
#include <sys/dsl_dataset.h>
#include <sys/spa.h>
static void
dnode_increase_indirection(dnode_t *dn, dmu_tx_t *tx)
{
dmu_buf_impl_t *db;
int txgoff = tx->tx_txg & TXG_MASK;
int nblkptr = dn->dn_phys->dn_nblkptr;
int old_toplvl = dn->dn_phys->dn_nlevels - 1;
int new_level = dn->dn_next_nlevels[txgoff];
int i;
rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
/* this dnode can't be paged out because it's dirty */
ASSERT(dn->dn_phys->dn_type != DMU_OT_NONE);
ASSERT(RW_WRITE_HELD(&dn->dn_struct_rwlock));
ASSERT(new_level > 1 && dn->dn_phys->dn_nlevels > 0);
db = dbuf_hold_level(dn, dn->dn_phys->dn_nlevels, 0, FTAG);
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);
/* check for existing blkptrs in the dnode */
for (i = 0; i < nblkptr; i++)
if (!BP_IS_HOLE(&dn->dn_phys->dn_blkptr[i]))
break;
if (i != nblkptr) {
/* transfer dnode's block pointers to new indirect block */
(void) dbuf_read(db, NULL, DB_RF_MUST_SUCCEED|DB_RF_HAVESTRUCT);
ASSERT(db->db.db_data);
ASSERT(arc_released(db->db_buf));
ASSERT3U(sizeof (blkptr_t) * nblkptr, <=, db->db.db_size);
bcopy(dn->dn_phys->dn_blkptr, db->db.db_data,
sizeof (blkptr_t) * nblkptr);
arc_buf_freeze(db->db_buf);
}
/* set dbuf's parent pointers to new indirect buf */
for (i = 0; i < nblkptr; i++) {
dmu_buf_impl_t *child = dbuf_find(dn, old_toplvl, i);
if (child == NULL)
continue;
#ifdef DEBUG
DB_DNODE_ENTER(child);
ASSERT3P(DB_DNODE(child), ==, dn);
DB_DNODE_EXIT(child);
#endif /* DEBUG */
if (child->db_parent && child->db_parent != dn->dn_dbuf) {
ASSERT(child->db_parent->db_level == db->db_level);
ASSERT(child->db_blkptr !=
&dn->dn_phys->dn_blkptr[child->db_blkid]);
mutex_exit(&child->db_mtx);
continue;
}
ASSERT(child->db_parent == NULL ||
child->db_parent == dn->dn_dbuf);
child->db_parent = db;
dbuf_add_ref(db, child);
if (db->db.db_data)
child->db_blkptr = (blkptr_t *)db->db.db_data + i;
else
child->db_blkptr = NULL;
dprintf_dbuf_bp(child, child->db_blkptr,
"changed db_blkptr to new indirect %s", "");
mutex_exit(&child->db_mtx);
}
bzero(dn->dn_phys->dn_blkptr, sizeof (blkptr_t) * nblkptr);
dbuf_rele(db, FTAG);
rw_exit(&dn->dn_struct_rwlock);
}
static int
free_blocks(dnode_t *dn, blkptr_t *bp, int num, dmu_tx_t *tx)
{
dsl_dataset_t *ds = dn->dn_objset->os_dsl_dataset;
uint64_t bytesfreed = 0;
int i, blocks_freed = 0;
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 += dsl_dataset_block_kill(ds, bp, tx, B_FALSE);
ASSERT3U(bytesfreed, <=, DN_USED_BYTES(dn->dn_phys));
bzero(bp, sizeof (blkptr_t));
blocks_freed += 1;
}
dnode_diduse_space(dn, -bytesfreed);
return (blocks_freed);
}
#ifdef ZFS_DEBUG
static void
free_verify(dmu_buf_impl_t *db, uint64_t start, uint64_t end, dmu_tx_t *tx)
{
int off, num;
int i, err, epbs;
uint64_t txg = tx->tx_txg;
dnode_t *dn;
DB_DNODE_ENTER(db);
dn = DB_DNODE(db);
epbs = dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT;
off = start - (db->db_blkid * 1<<epbs);
num = end - start + 1;
ASSERT3U(off, >=, 0);
ASSERT3U(num, >=, 0);
ASSERT3U(db->db_level, >, 0);
ASSERT3U(db->db.db_size, ==, 1 << dn->dn_phys->dn_indblkshift);
ASSERT3U(off+num, <=, db->db.db_size >> SPA_BLKPTRSHIFT);
ASSERT(db->db_blkptr != NULL);
for (i = off; i < off+num; i++) {
uint64_t *buf;
dmu_buf_impl_t *child;
dbuf_dirty_record_t *dr;
int j;
ASSERT(db->db_level == 1);
rw_enter(&dn->dn_struct_rwlock, RW_READER);
err = dbuf_hold_impl(dn, db->db_level-1,
(db->db_blkid << epbs) + i, TRUE, FTAG, &child);
rw_exit(&dn->dn_struct_rwlock);
if (err == ENOENT)
continue;
ASSERT(err == 0);
ASSERT(child->db_level == 0);
dr = child->db_last_dirty;
while (dr && dr->dr_txg > txg)
dr = dr->dr_next;
ASSERT(dr == NULL || dr->dr_txg == txg);
/* data_old better be zeroed */
if (dr) {
buf = dr->dt.dl.dr_data->b_data;
for (j = 0; j < child->db.db_size >> 3; j++) {
if (buf[j] != 0) {
panic("freed data not zero: "
"child=%p i=%d off=%d num=%d\n",
(void *)child, i, off, num);
}
}
}
/*
* db_data better be zeroed unless it's dirty in a
* future txg.
*/
mutex_enter(&child->db_mtx);
buf = child->db.db_data;
if (buf != NULL && child->db_state != DB_FILL &&
child->db_last_dirty == NULL) {
for (j = 0; j < child->db.db_size >> 3; j++) {
if (buf[j] != 0) {
panic("freed data not zero: "
"child=%p i=%d off=%d num=%d\n",
(void *)child, i, off, num);
}
}
}
mutex_exit(&child->db_mtx);
dbuf_rele(child, FTAG);
}
DB_DNODE_EXIT(db);
}
#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)
{
dnode_t *dn;
blkptr_t *bp;
dmu_buf_impl_t *subdb;
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);
dbuf_release_bp(db);
bp = (blkptr_t *)db->db.db_data;
DB_DNODE_ENTER(db);
dn = DB_DNODE(db);
epbs = dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT;
shift = (db->db_level - 1) * epbs;
dbstart = db->db_blkid << epbs;
start = blkid >> shift;
if (dbstart < start) {
bp += start - dbstart;
all = FALSE;
} else {
start = dbstart;
}
dbend = ((db->db_blkid + 1) << epbs) - 1;
end = (blkid + nblks - 1) >> shift;
if (dbend <= end)
end = dbend;
else if (all)
all = trunc;
ASSERT3U(start, <=, end);
if (db->db_level == 1) {
FREE_VERIFY(db, start, end, tx);
blocks_freed = free_blocks(dn, bp, end-start+1, tx);
arc_buf_freeze(db->db_buf);
ASSERT(all || blocks_freed == 0 || db->db_last_dirty);
DB_DNODE_EXIT(db);
return (all ? ALL : blocks_freed);
}
for (i = start; i <= end; i++, bp++) {
if (BP_IS_HOLE(bp))
continue;
rw_enter(&dn->dn_struct_rwlock, RW_READER);
err = dbuf_hold_impl(dn, db->db_level-1, i, TRUE, FTAG, &subdb);
ASSERT3U(err, ==, 0);
rw_exit(&dn->dn_struct_rwlock);
if (free_children(subdb, blkid, nblks, trunc, tx) == ALL) {
ASSERT3P(subdb->db_blkptr, ==, bp);
blocks_freed += free_blocks(dn, bp, 1, tx);
} else {
all = FALSE;
}
dbuf_rele(subdb, FTAG);
}
DB_DNODE_EXIT(db);
arc_buf_freeze(db->db_buf);
#ifdef ZFS_DEBUG
bp -= (end-start)+1;
for (i = start; i <= end; i++, bp++) {
if (i == start && blkid != 0)
continue;
else if (i == end && !trunc)
continue;
ASSERT3U(bp->blk_birth, ==, 0);
}
#endif
ASSERT(all || blocks_freed == 0 || db->db_last_dirty);
return (all ? ALL : blocks_freed);
}
/*
* free_range: Traverse the indicated range of the provided file
* and "free" all the blocks contained there.
*/
static void
dnode_sync_free_range(dnode_t *dn, uint64_t blkid, uint64_t nblks, dmu_tx_t *tx)
{
blkptr_t *bp = dn->dn_phys->dn_blkptr;
dmu_buf_impl_t *db;
int trunc, start, end, shift, i, err;
int dnlevel = dn->dn_phys->dn_nlevels;
if (blkid > dn->dn_phys->dn_maxblkid)
return;
ASSERT(dn->dn_phys->dn_maxblkid < UINT64_MAX);
trunc = blkid + nblks > dn->dn_phys->dn_maxblkid;
if (trunc)
nblks = dn->dn_phys->dn_maxblkid - blkid + 1;
/* There are no indirect blocks in the object */
if (dnlevel == 1) {
if (blkid >= dn->dn_phys->dn_nblkptr) {
/* this range was never made persistent */
return;
}
ASSERT3U(blkid + nblks, <=, dn->dn_phys->dn_nblkptr);
(void) free_blocks(dn, bp + blkid, nblks, tx);
if (trunc) {
ASSERTV(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, 0, &off, 1, 1, 0) != 0);
}
return;
}
shift = (dnlevel - 1) * (dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT);
start = blkid >> shift;
ASSERT(start < dn->dn_phys->dn_nblkptr);
end = (blkid + nblks - 1) >> shift;
bp += start;
for (i = start; i <= end; i++, bp++) {
if (BP_IS_HOLE(bp))
continue;
rw_enter(&dn->dn_struct_rwlock, RW_READER);
err = dbuf_hold_impl(dn, dnlevel-1, i, TRUE, FTAG, &db);
ASSERT3U(err, ==, 0);
rw_exit(&dn->dn_struct_rwlock);
if (free_children(db, blkid, nblks, trunc, tx) == ALL) {
ASSERT3P(db->db_blkptr, ==, bp);
(void) free_blocks(dn, bp, 1, tx);
}
dbuf_rele(db, FTAG);
}
if (trunc) {
ASSERTV(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, 0, &off, 1, 1, 0) != 0);
}
}
/*
* Try to kick all the dnodes dbufs out of the cache...
*/
void
dnode_evict_dbufs(dnode_t *dn)
{
int progress;
int pass = 0;
do {
dmu_buf_impl_t *db, marker;
int evicting = FALSE;
progress = FALSE;
mutex_enter(&dn->dn_dbufs_mtx);
list_insert_tail(&dn->dn_dbufs, &marker);
db = list_head(&dn->dn_dbufs);
for (; db != &marker; db = list_head(&dn->dn_dbufs)) {
list_remove(&dn->dn_dbufs, db);
list_insert_tail(&dn->dn_dbufs, db);
#ifdef DEBUG
DB_DNODE_ENTER(db);
ASSERT3P(DB_DNODE(db), ==, dn);
DB_DNODE_EXIT(db);
#endif /* DEBUG */
mutex_enter(&db->db_mtx);
if (db->db_state == DB_EVICTING) {
progress = TRUE;
evicting = TRUE;
mutex_exit(&db->db_mtx);
} else if (refcount_is_zero(&db->db_holds)) {
progress = TRUE;
dbuf_clear(db); /* exits db_mtx for us */
} else {
mutex_exit(&db->db_mtx);
}
}
list_remove(&dn->dn_dbufs, &marker);
/*
* NB: we need to drop dn_dbufs_mtx between passes so
* that any DB_EVICTING dbufs can make progress.
* Ideally, we would have some cv we could wait on, but
* since we don't, just wait a bit to give the other
* thread a chance to run.
*/
mutex_exit(&dn->dn_dbufs_mtx);
if (evicting)
delay(1);
pass++;
if ((pass % 100) == 0)
dprintf("Exceeded %d passes evicting dbufs\n", pass);
} while (progress);
if (pass >= 100)
dprintf("Required %d passes to evict dbufs\n", pass);
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);
dbuf_evict(dn->dn_bonus);
dn->dn_bonus = NULL;
}
rw_exit(&dn->dn_struct_rwlock);
}
static void
dnode_undirty_dbufs(list_t *list)
{
dbuf_dirty_record_t *dr;
while ((dr = list_head(list))) {
dmu_buf_impl_t *db = dr->dr_dbuf;
uint64_t txg = dr->dr_txg;
if (db->db_level != 0)
dnode_undirty_dbufs(&dr->dt.di.dr_children);
mutex_enter(&db->db_mtx);
/* XXX - use dbuf_undirty()? */
list_remove(list, dr);
ASSERT(db->db_last_dirty == dr);
db->db_last_dirty = NULL;
db->db_dirtycnt -= 1;
if (db->db_level == 0) {
ASSERT(db->db_blkid == DMU_BONUS_BLKID ||
dr->dt.dl.dr_data == db->db_buf);
dbuf_unoverride(dr);
}
kmem_free(dr, sizeof (dbuf_dirty_record_t));
dbuf_rele_and_unlock(db, (void *)(uintptr_t)txg);
}
}
static void
dnode_sync_free(dnode_t *dn, dmu_tx_t *tx)
{
int txgoff = tx->tx_txg & TXG_MASK;
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]);
dnode_evict_dbufs(dn);
ASSERT3P(list_head(&dn->dn_dbufs), ==, NULL);
/*
* XXX - It would be nice to assert this, but we may still
* have residual holds from async evictions from the arc...
*
* zfs_obj_to_path() also depends on this being
* commented out.
*
* ASSERT3U(refcount_count(&dn->dn_holds), ==, 1);
*/
/* Undirty next bits */
dn->dn_next_nlevels[txgoff] = 0;
dn->dn_next_indblkshift[txgoff] = 0;
dn->dn_next_blksz[txgoff] = 0;
/* ASSERT(blkptrs are zero); */
ASSERT(dn->dn_phys->dn_type != DMU_OT_NONE);
ASSERT(dn->dn_type != DMU_OT_NONE);
ASSERT(dn->dn_free_txg > 0);
if (dn->dn_allocated_txg != dn->dn_free_txg)
dbuf_will_dirty(dn->dn_dbuf, tx);
bzero(dn->dn_phys, sizeof (dnode_phys_t));
mutex_enter(&dn->dn_mtx);
dn->dn_type = DMU_OT_NONE;
dn->dn_maxblkid = 0;
dn->dn_allocated_txg = 0;
dn->dn_free_txg = 0;
dn->dn_have_spill = B_FALSE;
mutex_exit(&dn->dn_mtx);
ASSERT(dn->dn_object != DMU_META_DNODE_OBJECT);
dnode_rele(dn, (void *)(uintptr_t)tx->tx_txg);
/*
* Now that we've released our hold, the dnode may
* be evicted, so we musn't access it.
*/
}
/*
* Write out the dnode's dirty buffers.
*/
void
dnode_sync(dnode_t *dn, dmu_tx_t *tx)
{
free_range_t *rp;
dnode_phys_t *dnp = dn->dn_phys;
int txgoff = tx->tx_txg & TXG_MASK;
list_t *list = &dn->dn_dirty_records[txgoff];
boolean_t kill_spill = B_FALSE;
ASSERTV(static const dnode_phys_t zerodn = { 0 });
ASSERT(dmu_tx_is_syncing(tx));
ASSERT(dnp->dn_type != DMU_OT_NONE || dn->dn_allocated_txg);
ASSERT(dnp->dn_type != DMU_OT_NONE ||
bcmp(dnp, &zerodn, DNODE_SIZE) == 0);
DNODE_VERIFY(dn);
ASSERT(dn->dn_dbuf == NULL || arc_released(dn->dn_dbuf->db_buf));
if (dmu_objset_userused_enabled(dn->dn_objset) &&
!DMU_OBJECT_IS_SPECIAL(dn->dn_object)) {
mutex_enter(&dn->dn_mtx);
dn->dn_oldused = DN_USED_BYTES(dn->dn_phys);
dn->dn_oldflags = dn->dn_phys->dn_flags;
dn->dn_phys->dn_flags |= DNODE_FLAG_USERUSED_ACCOUNTED;
mutex_exit(&dn->dn_mtx);
dmu_objset_userquota_get_ids(dn, B_FALSE, tx);
} else {
/* Once we account for it, we should always account for it. */
ASSERT(!(dn->dn_phys->dn_flags &
DNODE_FLAG_USERUSED_ACCOUNTED));
}
mutex_enter(&dn->dn_mtx);
if (dn->dn_allocated_txg == tx->tx_txg) {
/* The dnode is newly allocated or reallocated */
if (dnp->dn_type == DMU_OT_NONE) {
/* this is a first alloc, not a realloc */
dnp->dn_nlevels = 1;
dnp->dn_nblkptr = dn->dn_nblkptr;
}
dnp->dn_type = dn->dn_type;
dnp->dn_bonustype = dn->dn_bonustype;
dnp->dn_bonuslen = dn->dn_bonuslen;
}
ASSERT(dnp->dn_nlevels > 1 ||
BP_IS_HOLE(&dnp->dn_blkptr[0]) ||
BP_GET_LSIZE(&dnp->dn_blkptr[0]) ==
dnp->dn_datablkszsec << SPA_MINBLOCKSHIFT);
if (dn->dn_next_blksz[txgoff]) {
ASSERT(P2PHASE(dn->dn_next_blksz[txgoff],
SPA_MINBLOCKSIZE) == 0);
ASSERT(BP_IS_HOLE(&dnp->dn_blkptr[0]) ||
dn->dn_maxblkid == 0 || list_head(list) != NULL ||
avl_last(&dn->dn_ranges[txgoff]) ||
dn->dn_next_blksz[txgoff] >> SPA_MINBLOCKSHIFT ==
dnp->dn_datablkszsec);
dnp->dn_datablkszsec =
dn->dn_next_blksz[txgoff] >> SPA_MINBLOCKSHIFT;
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_bonustype[txgoff]) {
ASSERT(dn->dn_next_bonustype[txgoff] < DMU_OT_NUMTYPES);
dnp->dn_bonustype = dn->dn_next_bonustype[txgoff];
dn->dn_next_bonustype[txgoff] = 0;
}
/*
* We will either remove a spill block when a file is being removed
* or we have been asked to remove it.
*/
if (dn->dn_rm_spillblk[txgoff] ||
((dnp->dn_flags & DNODE_FLAG_SPILL_BLKPTR) &&
dn->dn_free_txg > 0 && dn->dn_free_txg <= tx->tx_txg)) {
if ((dnp->dn_flags & DNODE_FLAG_SPILL_BLKPTR))
kill_spill = B_TRUE;
dn->dn_rm_spillblk[txgoff] = 0;
}
if (dn->dn_next_indblkshift[txgoff]) {
ASSERT(dnp->dn_nlevels == 1);
dnp->dn_indblkshift = dn->dn_next_indblkshift[txgoff];
dn->dn_next_indblkshift[txgoff] = 0;
}
/*
* Just take the live (open-context) values for checksum and compress.
* Strictly speaking it's a future leak, but nothing bad happens if we
* start using the new checksum or compress algorithm a little early.
*/
dnp->dn_checksum = dn->dn_checksum;
dnp->dn_compress = dn->dn_compress;
mutex_exit(&dn->dn_mtx);
if (kill_spill) {
(void) free_blocks(dn, &dn->dn_phys->dn_spill, 1, tx);
mutex_enter(&dn->dn_mtx);
dnp->dn_flags &= ~DNODE_FLAG_SPILL_BLKPTR;
mutex_exit(&dn->dn_mtx);
}
/* process all the "freed" ranges in the file */
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));
}
if (dn->dn_free_txg > 0 && dn->dn_free_txg <= tx->tx_txg) {
dnode_sync_free(dn, tx);
return;
}
if (dn->dn_next_nblkptr[txgoff]) {
/* this should only happen on a realloc */
ASSERT(dn->dn_allocated_txg == tx->tx_txg);
if (dn->dn_next_nblkptr[txgoff] > dnp->dn_nblkptr) {
/* zero the new blkptrs we are gaining */
bzero(dnp->dn_blkptr + dnp->dn_nblkptr,
sizeof (blkptr_t) *
(dn->dn_next_nblkptr[txgoff] - dnp->dn_nblkptr));
#ifdef ZFS_DEBUG
} else {
int i;
ASSERT(dn->dn_next_nblkptr[txgoff] < dnp->dn_nblkptr);
/* the blkptrs we are losing better be unallocated */
for (i = dn->dn_next_nblkptr[txgoff];
i < dnp->dn_nblkptr; i++)
ASSERT(BP_IS_HOLE(&dnp->dn_blkptr[i]));
#endif
}
mutex_enter(&dn->dn_mtx);
dnp->dn_nblkptr = dn->dn_next_nblkptr[txgoff];
dn->dn_next_nblkptr[txgoff] = 0;
mutex_exit(&dn->dn_mtx);
}
if (dn->dn_next_nlevels[txgoff]) {
dnode_increase_indirection(dn, tx);
dn->dn_next_nlevels[txgoff] = 0;
}
dbuf_sync_list(list, tx);
if (!DMU_OBJECT_IS_SPECIAL(dn->dn_object)) {
ASSERT3P(list_head(list), ==, NULL);
dnode_rele(dn, (void *)(uintptr_t)tx->tx_txg);
}
/*
* Although we have dropped our reference to the dnode, it
* can't be evicted until its written, and we haven't yet
* initiated the IO for the dnode's dbuf.
*/
}