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OpenZFS 7054 - dmu_tx_hold_t should use refcount_t to track space 

Authored by: Igor Kozhukhov ikozhukhov@gmail.com
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Paul Dagnelie <pcd@delphix.com>
Reviewed by: Igor Kozhukhov <ikozhukhov@gmail.com>
Approved by: Dan McDonald <danmcd@omniti.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Ported-by: George Melikov mail@gmelikov.ru

OpenZFS-issue: https://www.illumos.org/issues/7054
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/0c779ad
Closes #5600
This commit is contained in:
George Melikov 2017-01-23 20:36:24 +03:00 committed by Brian Behlendorf
parent 4ea3f86426
commit f85c06bedf
6 changed files with 194 additions and 116 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
include/sys/dmu_tx.h
View File

@ -23,7 +23,7 @@
* Use is subject to license terms.
*/
/*
* Copyright (c) 2013 by Delphix. All rights reserved.
* Copyright (c) 2012, 2015 by Delphix. All rights reserved.
*/
#ifndef _SYS_DMU_TX_H
@ -102,12 +102,12 @@ typedef struct dmu_tx_hold {
dmu_tx_t *txh_tx;
list_node_t txh_node;
struct dnode *txh_dnode;
uint64_t txh_space_towrite;
uint64_t txh_space_tofree;
uint64_t txh_space_tooverwrite;
uint64_t txh_space_tounref;
uint64_t txh_memory_tohold;
uint64_t txh_fudge;
refcount_t txh_space_towrite;
refcount_t txh_space_tofree;
refcount_t txh_space_tooverwrite;
refcount_t txh_space_tounref;
refcount_t txh_memory_tohold;
refcount_t txh_fudge;
#ifdef DEBUG_DMU_TX
enum dmu_tx_hold_type txh_type;
uint64_t txh_arg1;

2
include/sys/zap.h
View File

@ -244,7 +244,7 @@ int zap_lookup_norm_by_dnode(dnode_t *dn, const char *name,
boolean_t *ncp);
int zap_count_write_by_dnode(dnode_t *dn, const char *name,
int add, uint64_t *towrite, uint64_t *tooverwrite);
int add, refcount_t *towrite, refcount_t *tooverwrite);
/*
* Create an attribute with the given name and value.

4
include/sys/zap_impl.h
View File

@ -213,8 +213,8 @@ int fzap_lookup(zap_name_t *zn,
uint64_t integer_size, uint64_t num_integers, void *buf,
char *realname, int rn_len, boolean_t *normalization_conflictp);
void fzap_prefetch(zap_name_t *zn);
int fzap_count_write(zap_name_t *zn, int add, uint64_t *towrite,
uint64_t *tooverwrite);
int fzap_count_write(zap_name_t *zn, int add, refcount_t *towrite,
refcount_t *tooverwrite);
int fzap_add(zap_name_t *zn, uint64_t integer_size, uint64_t num_integers,
const void *val, void *tag, dmu_tx_t *tx);
int fzap_update(zap_name_t *zn,

238
module/zfs/dmu_tx.c
View File

@ -137,6 +137,12 @@ dmu_tx_hold_dnode_impl(dmu_tx_t *tx, dnode_t *dn, enum dmu_tx_hold_type type,
txh = kmem_zalloc(sizeof (dmu_tx_hold_t), KM_SLEEP);
txh->txh_tx = tx;
txh->txh_dnode = dn;
refcount_create(&txh->txh_space_towrite);
refcount_create(&txh->txh_space_tofree);
refcount_create(&txh->txh_space_tooverwrite);
refcount_create(&txh->txh_space_tounref);
refcount_create(&txh->txh_memory_tohold);
refcount_create(&txh->txh_fudge);
#ifdef DEBUG_DMU_TX
txh->txh_type = type;
txh->txh_arg1 = arg1;
@ -228,12 +234,18 @@ dmu_tx_count_twig(dmu_tx_hold_t *txh, dnode_t *dn, dmu_buf_impl_t *db,
freeable = (bp && (freeable ||
dsl_dataset_block_freeable(ds, bp, bp->blk_birth)));
if (freeable)
txh->txh_space_tooverwrite += space;
else
txh->txh_space_towrite += space;
if (bp)
txh->txh_space_tounref += bp_get_dsize(os->os_spa, bp);
if (freeable) {
(void) refcount_add_many(&txh->txh_space_tooverwrite,
space, FTAG);
} else {
(void) refcount_add_many(&txh->txh_space_towrite,
space, FTAG);
}
if (bp) {
(void) refcount_add_many(&txh->txh_space_tounref,
bp_get_dsize(os->os_spa, bp), FTAG);
}
dmu_tx_count_twig(txh, dn, parent, level + 1,
blkid >> epbs, freeable, history);
@ -364,8 +376,11 @@ dmu_tx_count_write(dmu_tx_hold_t *txh, uint64_t off, uint64_t len)
bits = 64 - min_bs;
epbs = min_ibs - SPA_BLKPTRSHIFT;
for (bits -= epbs * (nlvls - 1);
bits >= 0; bits -= epbs)
txh->txh_fudge += 1ULL << max_ibs;
bits >= 0; bits -= epbs) {
(void) refcount_add_many(
&txh->txh_fudge,
1ULL << max_ibs, FTAG);
}
goto out;
}
off += delta;
@ -381,7 +396,8 @@ dmu_tx_count_write(dmu_tx_hold_t *txh, uint64_t off, uint64_t len)
*/
start = P2ALIGN(off, 1ULL << max_bs);
end = P2ROUNDUP(off + len, 1ULL << max_bs) - 1;
txh->txh_space_towrite += end - start + 1;
(void) refcount_add_many(&txh->txh_space_towrite,
end - start + 1, FTAG);
start >>= min_bs;
end >>= min_bs;
@ -396,18 +412,21 @@ dmu_tx_count_write(dmu_tx_hold_t *txh, uint64_t off, uint64_t len)
start >>= epbs;
end >>= epbs;
ASSERT3U(end, >=, start);
txh->txh_space_towrite += (end - start + 1) << max_ibs;
(void) refcount_add_many(&txh->txh_space_towrite,
(end - start + 1) << max_ibs, FTAG);
if (start != 0) {
/*
* We also need a new blkid=0 indirect block
* to reference any existing file data.
*/
txh->txh_space_towrite += 1ULL << max_ibs;
(void) refcount_add_many(&txh->txh_space_towrite,
1ULL << max_ibs, FTAG);
}
}
out:
if (txh->txh_space_towrite + txh->txh_space_tooverwrite >
if (refcount_count(&txh->txh_space_towrite) +
refcount_count(&txh->txh_space_tooverwrite) >
2 * DMU_MAX_ACCESS)
err = SET_ERROR(EFBIG);
@ -426,12 +445,15 @@ dmu_tx_count_dnode(dmu_tx_hold_t *txh)
if (dn && dn->dn_dbuf->db_blkptr &&
dsl_dataset_block_freeable(dn->dn_objset->os_dsl_dataset,
dn->dn_dbuf->db_blkptr, dn->dn_dbuf->db_blkptr->blk_birth)) {
txh->txh_space_tooverwrite += space;
txh->txh_space_tounref += space;
(void) refcount_add_many(&txh->txh_space_tooverwrite,
space, FTAG);
(void) refcount_add_many(&txh->txh_space_tounref, space, FTAG);
} else {
txh->txh_space_towrite += space;
if (dn && dn->dn_dbuf->db_blkptr)
txh->txh_space_tounref += space;
(void) refcount_add_many(&txh->txh_space_towrite, space, FTAG);
if (dn && dn->dn_dbuf->db_blkptr) {
(void) refcount_add_many(&txh->txh_space_tounref,
space, FTAG);
}
}
}
@ -570,7 +592,8 @@ dmu_tx_count_free(dmu_tx_hold_t *txh, uint64_t off, uint64_t len)
break;
}
txh->txh_memory_tohold += dbuf->db.db_size;
(void) refcount_add_many(&txh->txh_memory_tohold,
dbuf->db.db_size, FTAG);
/*
* We don't check memory_tohold against DMU_MAX_ACCESS because
@ -623,20 +646,23 @@ dmu_tx_count_free(dmu_tx_hold_t *txh, uint64_t off, uint64_t len)
(dn->dn_indblkshift - SPA_BLKPTRSHIFT);
while (level++ < maxlevel) {
txh->txh_memory_tohold += MAX(MIN(blkcnt, nl1blks), 1)
<< dn->dn_indblkshift;
(void) refcount_add_many(&txh->txh_memory_tohold,
MAX(MIN(blkcnt, nl1blks), 1) << dn->dn_indblkshift,
FTAG);
blkcnt = 1 + (blkcnt >> epbs);
}
}
/* account for new level 1 indirect blocks that might show up */
if (skipped > 0) {
txh->txh_fudge += skipped << dn->dn_indblkshift;
(void) refcount_add_many(&txh->txh_fudge,
skipped << dn->dn_indblkshift, FTAG);
skipped = MIN(skipped, DMU_MAX_DELETEBLKCNT >> epbs);
txh->txh_memory_tohold += skipped << dn->dn_indblkshift;
(void) refcount_add_many(&txh->txh_memory_tohold,
skipped << dn->dn_indblkshift, FTAG);
}
txh->txh_space_tofree += space;
txh->txh_space_tounref += unref;
(void) refcount_add_many(&txh->txh_space_tofree, space, FTAG);
(void) refcount_add_many(&txh->txh_space_tounref, unref, FTAG);
}
/*
@ -662,7 +688,10 @@ dmu_tx_mark_netfree(dmu_tx_t *tx)
* cause overflows when doing math with these values (e.g. in
* dmu_tx_try_assign()).
*/
txh->txh_space_tofree = txh->txh_space_tounref = 1024 * 1024 * 1024;
(void) refcount_add_many(&txh->txh_space_tofree,
1024 * 1024 * 1024, FTAG);
(void) refcount_add_many(&txh->txh_space_tounref,
1024 * 1024 * 1024, FTAG);
}
static void
@ -784,9 +813,10 @@ dmu_tx_hold_zap_impl(dmu_tx_hold_t *txh, int add, const char *name)
{
dmu_tx_t *tx = txh->txh_tx;
dnode_t *dn;
int err;
int epbs;
dsl_dataset_phys_t *ds_phys;
uint64_t nblocks;
int epbs, err;
int lvl;
ASSERT(tx->tx_txg == 0);
@ -825,12 +855,17 @@ dmu_tx_hold_zap_impl(dmu_tx_hold_t *txh, int add, const char *name)
*/
bp = &dn->dn_phys->dn_blkptr[0];
if (dsl_dataset_block_freeable(dn->dn_objset->os_dsl_dataset,
bp, bp->blk_birth))
txh->txh_space_tooverwrite += MZAP_MAX_BLKSZ;
else
txh->txh_space_towrite += MZAP_MAX_BLKSZ;
if (!BP_IS_HOLE(bp))
txh->txh_space_tounref += MZAP_MAX_BLKSZ;
bp, bp->blk_birth)) {
(void) refcount_add_many(&txh->txh_space_tooverwrite,
MZAP_MAX_BLKSZ, FTAG);
} else {
(void) refcount_add_many(&txh->txh_space_towrite,
MZAP_MAX_BLKSZ, FTAG);
}
if (!BP_IS_HOLE(bp)) {
(void) refcount_add_many(&txh->txh_space_tounref,
MZAP_MAX_BLKSZ, FTAG);
}
return;
}
@ -851,15 +886,29 @@ dmu_tx_hold_zap_impl(dmu_tx_hold_t *txh, int add, const char *name)
/*
* If the modified blocks are scattered to the four winds,
* we'll have to modify an indirect twig for each.
* we'll have to modify an indirect twig for each. We can make
* modifications at up to 3 locations:
* - header block at the beginning of the object
* - target leaf block
* - end of the object, where we might need to write:
* - a new leaf block if the target block needs to be split
* - the new pointer table, if it is growing
* - the new cookie table, if it is growing
*/
epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT;
ds_phys = dsl_dataset_phys(dn->dn_objset->os_dsl_dataset);
for (nblocks = dn->dn_maxblkid >> epbs; nblocks != 0; nblocks >>= epbs)
if (ds_phys->ds_prev_snap_obj)
txh->txh_space_towrite += 3 << dn->dn_indblkshift;
else
txh->txh_space_tooverwrite += 3 << dn->dn_indblkshift;
ds_phys =
dsl_dataset_phys(dn->dn_objset->os_dsl_dataset);
for (lvl = 1; lvl < dn->dn_nlevels; lvl++) {
uint64_t num_indirects = 1 + (dn->dn_maxblkid >> (epbs * lvl));
uint64_t spc = MIN(3, num_indirects) << dn->dn_indblkshift;
if (ds_phys->ds_prev_snap_obj != 0) {
(void) refcount_add_many(&txh->txh_space_towrite,
spc, FTAG);
} else {
(void) refcount_add_many(&txh->txh_space_tooverwrite,
spc, FTAG);
}
}
}
void
@ -925,7 +974,7 @@ dmu_tx_hold_space(dmu_tx_t *tx, uint64_t space)
txh = dmu_tx_hold_object_impl(tx, tx->tx_objset,
DMU_NEW_OBJECT, THT_SPACE, space, 0);
if (txh)
txh->txh_space_towrite += space;
(void) refcount_add_many(&txh->txh_space_towrite, space, FTAG);
}
int
@ -1267,12 +1316,12 @@ dmu_tx_try_assign(dmu_tx_t *tx, txg_how_t txg_how)
(void) refcount_add(&dn->dn_tx_holds, tx);
mutex_exit(&dn->dn_mtx);
}
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;
towrite += refcount_count(&txh->txh_space_towrite);
tofree += refcount_count(&txh->txh_space_tofree);
tooverwrite += refcount_count(&txh->txh_space_tooverwrite);
tounref += refcount_count(&txh->txh_space_tounref);
tohold += refcount_count(&txh->txh_memory_tohold);
fudge += refcount_count(&txh->txh_fudge);
}
/*
@ -1487,6 +1536,43 @@ dmu_tx_willuse_space(dmu_tx_t *tx, int64_t delta)
#endif
}
static void
dmu_tx_destroy(dmu_tx_t *tx)
{
dmu_tx_hold_t *txh;
while ((txh = list_head(&tx->tx_holds)) != NULL) {
dnode_t *dn = txh->txh_dnode;
list_remove(&tx->tx_holds, txh);
refcount_destroy_many(&txh->txh_space_towrite,
refcount_count(&txh->txh_space_towrite));
refcount_destroy_many(&txh->txh_space_tofree,
refcount_count(&txh->txh_space_tofree));
refcount_destroy_many(&txh->txh_space_tooverwrite,
refcount_count(&txh->txh_space_tooverwrite));
refcount_destroy_many(&txh->txh_space_tounref,
refcount_count(&txh->txh_space_tounref));
refcount_destroy_many(&txh->txh_memory_tohold,
refcount_count(&txh->txh_memory_tohold));
refcount_destroy_many(&txh->txh_fudge,
refcount_count(&txh->txh_fudge));
kmem_free(txh, sizeof (dmu_tx_hold_t));
if (dn != NULL)
dnode_rele(dn, tx);
}
list_destroy(&tx->tx_callbacks);
list_destroy(&tx->tx_holds);
#ifdef DEBUG_DMU_TX
refcount_destroy_many(&tx->tx_space_written,
refcount_count(&tx->tx_space_written));
refcount_destroy_many(&tx->tx_space_freed,
refcount_count(&tx->tx_space_freed));
#endif
kmem_free(tx, sizeof (dmu_tx_t));
}
void
dmu_tx_commit(dmu_tx_t *tx)
{
@ -1498,13 +1584,13 @@ dmu_tx_commit(dmu_tx_t *tx)
* Go through the transaction's hold list and remove holds on
* associated dnodes, notifying waiters if no holds remain.
*/
while ((txh = list_head(&tx->tx_holds))) {
for (txh = list_head(&tx->tx_holds); txh != NULL;
txh = list_next(&tx->tx_holds, txh)) {
dnode_t *dn = txh->txh_dnode;
list_remove(&tx->tx_holds, txh);
kmem_free(txh, sizeof (dmu_tx_hold_t));
if (dn == NULL)
continue;
mutex_enter(&dn->dn_mtx);
ASSERT3U(dn->dn_assigned_txg, ==, tx->tx_txg);
@ -1513,7 +1599,6 @@ dmu_tx_commit(dmu_tx_t *tx)
cv_broadcast(&dn->dn_notxholds);
}
mutex_exit(&dn->dn_mtx);
dnode_rele(dn, tx);
}
if (tx->tx_tempreserve_cookie)
@ -1525,51 +1610,26 @@ dmu_tx_commit(dmu_tx_t *tx)
if (tx->tx_anyobj == FALSE)
txg_rele_to_sync(&tx->tx_txgh);
list_destroy(&tx->tx_callbacks);
list_destroy(&tx->tx_holds);
#ifdef DEBUG_DMU_TX
dprintf("towrite=%llu written=%llu tofree=%llu freed=%llu\n",
tx->tx_space_towrite, refcount_count(&tx->tx_space_written),
tx->tx_space_tofree, refcount_count(&tx->tx_space_freed));
refcount_destroy_many(&tx->tx_space_written,
refcount_count(&tx->tx_space_written));
refcount_destroy_many(&tx->tx_space_freed,
refcount_count(&tx->tx_space_freed));
#endif
kmem_free(tx, sizeof (dmu_tx_t));
dmu_tx_destroy(tx);
}
void
dmu_tx_abort(dmu_tx_t *tx)
{
dmu_tx_hold_t *txh;
ASSERT(tx->tx_txg == 0);
while ((txh = list_head(&tx->tx_holds))) {
dnode_t *dn = txh->txh_dnode;
list_remove(&tx->tx_holds, txh);
kmem_free(txh, sizeof (dmu_tx_hold_t));
if (dn != NULL)
dnode_rele(dn, tx);
}
/*
* Call any registered callbacks with an error code.
*/
if (!list_is_empty(&tx->tx_callbacks))
dmu_tx_do_callbacks(&tx->tx_callbacks, ECANCELED);
list_destroy(&tx->tx_callbacks);
list_destroy(&tx->tx_holds);
#ifdef DEBUG_DMU_TX
refcount_destroy_many(&tx->tx_space_written,
refcount_count(&tx->tx_space_written));
refcount_destroy_many(&tx->tx_space_freed,
refcount_count(&tx->tx_space_freed));
#endif
kmem_free(tx, sizeof (dmu_tx_t));
dmu_tx_destroy(tx);
}
uint64_t
@ -1607,7 +1667,7 @@ dmu_tx_do_callbacks(list_t *cb_list, int error)
{
dmu_tx_callback_t *dcb;
while ((dcb = list_head(cb_list))) {
while ((dcb = list_head(cb_list)) != NULL) {
list_remove(cb_list, dcb);
dcb->dcb_func(dcb->dcb_data, error);
kmem_free(dcb, sizeof (dmu_tx_callback_t));
@ -1667,18 +1727,24 @@ dmu_tx_hold_spill(dmu_tx_t *tx, uint64_t object)
/* If blkptr doesn't exist then add space to towrite */
if (!(dn->dn_phys->dn_flags & DNODE_FLAG_SPILL_BLKPTR)) {
txh->txh_space_towrite += SPA_OLD_MAXBLOCKSIZE;
(void) refcount_add_many(&txh->txh_space_towrite,
SPA_OLD_MAXBLOCKSIZE, FTAG);
} else {
blkptr_t *bp;
bp = DN_SPILL_BLKPTR(dn->dn_phys);
if (dsl_dataset_block_freeable(dn->dn_objset->os_dsl_dataset,
bp, bp->blk_birth))
txh->txh_space_tooverwrite += SPA_OLD_MAXBLOCKSIZE;
else
txh->txh_space_towrite += SPA_OLD_MAXBLOCKSIZE;
if (!BP_IS_HOLE(bp))
txh->txh_space_tounref += SPA_OLD_MAXBLOCKSIZE;
bp, bp->blk_birth)) {
(void) refcount_add_many(&txh->txh_space_tooverwrite,
SPA_OLD_MAXBLOCKSIZE, FTAG);
} else {
(void) refcount_add_many(&txh->txh_space_towrite,
SPA_OLD_MAXBLOCKSIZE, FTAG);
}
if (!BP_IS_HOLE(bp)) {
(void) refcount_add_many(&txh->txh_space_tounref,
SPA_OLD_MAXBLOCKSIZE, FTAG);
}
}
}

26
module/zfs/zap.c
View File

@ -1358,8 +1358,8 @@ fzap_get_stats(zap_t *zap, zap_stats_t *zs)
}
int
fzap_count_write(zap_name_t *zn, int add, uint64_t *towrite,
uint64_t *tooverwrite)
fzap_count_write(zap_name_t *zn, int add, refcount_t *towrite,
refcount_t *tooverwrite)
{
zap_t *zap = zn->zn_zap;
zap_leaf_t *l;
@ -1369,9 +1369,11 @@ fzap_count_write(zap_name_t *zn, int add, uint64_t *towrite,
* Account for the header block of the fatzap.
*/
if (!add && dmu_buf_freeable(zap->zap_dbuf)) {
*tooverwrite += zap->zap_dbuf->db_size;
(void) refcount_add_many(tooverwrite,
zap->zap_dbuf->db_size, FTAG);
} else {
*towrite += zap->zap_dbuf->db_size;
(void) refcount_add_many(towrite,
zap->zap_dbuf->db_size, FTAG);
}
/*
@ -1383,10 +1385,13 @@ fzap_count_write(zap_name_t *zn, int add, uint64_t *towrite,
* could extend the table.
*/
if (add) {
if (zap_f_phys(zap)->zap_ptrtbl.zt_blk == 0)
*towrite += zap->zap_dbuf->db_size;
else
*towrite += (zap->zap_dbuf->db_size * 3);
if (zap_f_phys(zap)->zap_ptrtbl.zt_blk == 0) {
(void) refcount_add_many(towrite,
zap->zap_dbuf->db_size, FTAG);
} else {
(void) refcount_add_many(towrite,
zap->zap_dbuf->db_size * 3, FTAG);
}
}
/*
@ -1399,13 +1404,14 @@ fzap_count_write(zap_name_t *zn, int add, uint64_t *towrite,
}
if (!add && dmu_buf_freeable(l->l_dbuf)) {
*tooverwrite += l->l_dbuf->db_size;
(void) refcount_add_many(tooverwrite, l->l_dbuf->db_size, FTAG);
} else {
/*
* If this an add operation, the leaf block could split.
* Hence, we need to account for an additional leaf block.
*/
*towrite += (add ? 2 : 1) * l->l_dbuf->db_size;
(void) refcount_add_many(towrite,
(add ? 2 : 1) * l->l_dbuf->db_size, FTAG);
}
zap_put_leaf(l);

22
module/zfs/zap_micro.c
View File

@ -1552,7 +1552,7 @@ zap_get_stats(objset_t *os, uint64_t zapobj, zap_stats_t *zs)
int
zap_count_write_by_dnode(dnode_t *dn, const char *name, int add,
uint64_t *towrite, uint64_t *tooverwrite)
refcount_t *towrite, refcount_t *tooverwrite)
{
zap_t *zap;
int err = 0;
@ -1569,7 +1569,8 @@ zap_count_write_by_dnode(dnode_t *dn, const char *name, int add,
* large microzap results in a promotion to fatzap.
*/
if (name == NULL) {
*towrite += (3 + (add ? 4 : 0)) * SPA_OLD_MAXBLOCKSIZE;
(void) refcount_add_many(towrite,
(3 + (add ? 4 : 0)) * SPA_OLD_MAXBLOCKSIZE, FTAG);
return (err);
}
@ -1594,7 +1595,8 @@ zap_count_write_by_dnode(dnode_t *dn, const char *name, int add,
/*
* We treat this case as similar to (name == NULL)
*/
*towrite += (3 + (add ? 4 : 0)) * SPA_OLD_MAXBLOCKSIZE;
(void) refcount_add_many(towrite,
(3 + (add ? 4 : 0)) * SPA_OLD_MAXBLOCKSIZE, FTAG);
}
} else {
/*
@ -1612,13 +1614,17 @@ zap_count_write_by_dnode(dnode_t *dn, const char *name, int add,
* 4 new blocks written : 2 new split leaf, 2 grown
* ptrtbl blocks
*/
if (dmu_buf_freeable(zap->zap_dbuf))
*tooverwrite += MZAP_MAX_BLKSZ;
else
*towrite += MZAP_MAX_BLKSZ;
if (dmu_buf_freeable(zap->zap_dbuf)) {
(void) refcount_add_many(tooverwrite,
MZAP_MAX_BLKSZ, FTAG);
} else {
(void) refcount_add_many(towrite,
MZAP_MAX_BLKSZ, FTAG);
}
if (add) {
*towrite += 4 * MZAP_MAX_BLKSZ;
(void) refcount_add_many(towrite,
4 * MZAP_MAX_BLKSZ, FTAG);
}
}