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mirror_zfs/module/zfs/dmu_tx.c
Matthew Ahrens 66eead53c9 Clean up by-dnode code in dmu_tx.c 
0eef1bde31
introduced some changes which we slightly improved the style of when
porting to illumos.

There is also one minor error-handling fix, in zap_add() the "zap" may
become NULL in case of an error re-opening the ZAP.

Originally suggested at: https://github.com/openzfs/openzfs/pull/276

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed by: Pavel Zakharov <pavel.zakharov@delphix.com>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes #5805
2017-02-24 13:34:26 -08:00

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/*
* 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 2011 Nexenta Systems, Inc. All rights reserved.
* Copyright (c) 2012, 2016 by Delphix. All rights reserved.
*/
#include <sys/dmu.h>
#include <sys/dmu_impl.h>
#include <sys/dbuf.h>
#include <sys/dmu_tx.h>
#include <sys/dmu_objset.h>
#include <sys/dsl_dataset.h> /* for dsl_dataset_block_freeable() */
#include <sys/dsl_dir.h> /* for dsl_dir_tempreserve_*() */
#include <sys/dsl_pool.h>
#include <sys/zap_impl.h> /* for fzap_default_block_shift */
#include <sys/spa.h>
#include <sys/sa.h>
#include <sys/sa_impl.h>
#include <sys/zfs_context.h>
#include <sys/varargs.h>
#include <sys/trace_dmu.h>
typedef void (*dmu_tx_hold_func_t)(dmu_tx_t *tx, struct dnode *dn,
uint64_t arg1, uint64_t arg2);
dmu_tx_stats_t dmu_tx_stats = {
{ "dmu_tx_assigned", KSTAT_DATA_UINT64 },
{ "dmu_tx_delay", KSTAT_DATA_UINT64 },
{ "dmu_tx_error", KSTAT_DATA_UINT64 },
{ "dmu_tx_suspended", KSTAT_DATA_UINT64 },
{ "dmu_tx_group", KSTAT_DATA_UINT64 },
{ "dmu_tx_memory_reserve", KSTAT_DATA_UINT64 },
{ "dmu_tx_memory_reclaim", KSTAT_DATA_UINT64 },
{ "dmu_tx_dirty_throttle", KSTAT_DATA_UINT64 },
{ "dmu_tx_dirty_delay", KSTAT_DATA_UINT64 },
{ "dmu_tx_dirty_over_max", KSTAT_DATA_UINT64 },
{ "dmu_tx_quota", KSTAT_DATA_UINT64 },
};
static kstat_t *dmu_tx_ksp;
dmu_tx_t *
dmu_tx_create_dd(dsl_dir_t *dd)
{
dmu_tx_t *tx = kmem_zalloc(sizeof (dmu_tx_t), KM_SLEEP);
tx->tx_dir = dd;
if (dd != NULL)
tx->tx_pool = dd->dd_pool;
list_create(&tx->tx_holds, sizeof (dmu_tx_hold_t),
offsetof(dmu_tx_hold_t, txh_node));
list_create(&tx->tx_callbacks, sizeof (dmu_tx_callback_t),
offsetof(dmu_tx_callback_t, dcb_node));
tx->tx_start = gethrtime();
#ifdef DEBUG_DMU_TX
refcount_create(&tx->tx_space_written);
refcount_create(&tx->tx_space_freed);
#endif
return (tx);
}
dmu_tx_t *
dmu_tx_create(objset_t *os)
{
dmu_tx_t *tx = dmu_tx_create_dd(os->os_dsl_dataset->ds_dir);
tx->tx_objset = os;
tx->tx_lastsnap_txg = dsl_dataset_prev_snap_txg(os->os_dsl_dataset);
return (tx);
}
dmu_tx_t *
dmu_tx_create_assigned(struct dsl_pool *dp, uint64_t txg)
{
dmu_tx_t *tx = dmu_tx_create_dd(NULL);
ASSERT3U(txg, <=, dp->dp_tx.tx_open_txg);
tx->tx_pool = dp;
tx->tx_txg = txg;
tx->tx_anyobj = TRUE;
return (tx);
}
int
dmu_tx_is_syncing(dmu_tx_t *tx)
{
return (tx->tx_anyobj);
}
int
dmu_tx_private_ok(dmu_tx_t *tx)
{
return (tx->tx_anyobj);
}
static dmu_tx_hold_t *
dmu_tx_hold_dnode_impl(dmu_tx_t *tx, dnode_t *dn, enum dmu_tx_hold_type type,
uint64_t arg1, uint64_t arg2)
{
dmu_tx_hold_t *txh;
if (dn != NULL) {
(void) refcount_add(&dn->dn_holds, tx);
if (tx->tx_txg != 0) {
mutex_enter(&dn->dn_mtx);
/*
* dn->dn_assigned_txg == tx->tx_txg doesn't pose a
* problem, but there's no way for it to happen (for
* now, at least).
*/
ASSERT(dn->dn_assigned_txg == 0);
dn->dn_assigned_txg = tx->tx_txg;
(void) refcount_add(&dn->dn_tx_holds, tx);
mutex_exit(&dn->dn_mtx);
}
}
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;
txh->txh_arg2 = arg2;
#endif
list_insert_tail(&tx->tx_holds, txh);
return (txh);
}
static dmu_tx_hold_t *
dmu_tx_hold_object_impl(dmu_tx_t *tx, objset_t *os, uint64_t object,
enum dmu_tx_hold_type type, uint64_t arg1, uint64_t arg2)
{
dnode_t *dn = NULL;
dmu_tx_hold_t *txh;
int err;
if (object != DMU_NEW_OBJECT) {
err = dnode_hold(os, object, FTAG, &dn);
if (err != 0) {
tx->tx_err = err;
return (NULL);
}
}
txh = dmu_tx_hold_dnode_impl(tx, dn, type, arg1, arg2);
if (dn != NULL)
dnode_rele(dn, FTAG);
return (txh);
}
void
dmu_tx_add_new_object(dmu_tx_t *tx, dnode_t *dn)
{
/*
* If we're syncing, they can manipulate any object anyhow, and
* the hold on the dnode_t can cause problems.
*/
if (!dmu_tx_is_syncing(tx))
(void) dmu_tx_hold_dnode_impl(tx, dn, THT_NEWOBJECT, 0, 0);
}
static int
dmu_tx_check_ioerr(zio_t *zio, dnode_t *dn, int level, uint64_t blkid)
{
int err;
dmu_buf_impl_t *db;
rw_enter(&dn->dn_struct_rwlock, RW_READER);
db = dbuf_hold_level(dn, level, blkid, FTAG);
rw_exit(&dn->dn_struct_rwlock);
if (db == NULL)
return (SET_ERROR(EIO));
err = dbuf_read(db, zio, DB_RF_CANFAIL | DB_RF_NOPREFETCH);
dbuf_rele(db, FTAG);
return (err);
}
static void
dmu_tx_count_twig(dmu_tx_hold_t *txh, dnode_t *dn, dmu_buf_impl_t *db,
int level, uint64_t blkid, boolean_t freeable, uint64_t *history)
{
objset_t *os = dn->dn_objset;
dsl_dataset_t *ds = os->os_dsl_dataset;
int epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT;
dmu_buf_impl_t *parent = NULL;
blkptr_t *bp = NULL;
uint64_t space;
if (level >= dn->dn_nlevels || history[level] == blkid)
return;
history[level] = blkid;
space = (level == 0) ? dn->dn_datablksz : (1ULL << dn->dn_indblkshift);
if (db == NULL || db == dn->dn_dbuf) {
ASSERT(level != 0);
db = NULL;
} else {
ASSERT(DB_DNODE(db) == dn);
ASSERT(db->db_level == level);
ASSERT(db->db.db_size == space);
ASSERT(db->db_blkid == blkid);
bp = db->db_blkptr;
parent = db->db_parent;
}
freeable = (bp && (freeable ||
dsl_dataset_block_freeable(ds, bp, bp->blk_birth)));
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);
}
/* ARGSUSED */
static void
dmu_tx_count_write(dmu_tx_hold_t *txh, uint64_t off, uint64_t len)
{
dnode_t *dn = txh->txh_dnode;
uint64_t start, end, i;
int min_bs, max_bs, min_ibs, max_ibs, epbs, bits;
int err = 0;
int l;
if (len == 0)
return;
min_bs = SPA_MINBLOCKSHIFT;
max_bs = highbit64(txh->txh_tx->tx_objset->os_recordsize) - 1;
min_ibs = DN_MIN_INDBLKSHIFT;
max_ibs = DN_MAX_INDBLKSHIFT;
if (dn) {
uint64_t history[DN_MAX_LEVELS];
int nlvls = dn->dn_nlevels;
int delta;
/*
* For i/o error checking, read the first and last level-0
* blocks (if they are not aligned), and all the level-1 blocks.
*/
if (dn->dn_maxblkid == 0) {
delta = dn->dn_datablksz;
start = (off < dn->dn_datablksz) ? 0 : 1;
end = (off+len <= dn->dn_datablksz) ? 0 : 1;
if (start == 0 && (off > 0 || len < dn->dn_datablksz)) {
err = dmu_tx_check_ioerr(NULL, dn, 0, 0);
if (err)
goto out;
delta -= off;
}
} else {
zio_t *zio = zio_root(dn->dn_objset->os_spa,
NULL, NULL, ZIO_FLAG_CANFAIL);
/* first level-0 block */
start = off >> dn->dn_datablkshift;
if (P2PHASE(off, dn->dn_datablksz) ||
len < dn->dn_datablksz) {
err = dmu_tx_check_ioerr(zio, dn, 0, start);
if (err)
goto out;
}
/* last level-0 block */
end = (off+len-1) >> dn->dn_datablkshift;
if (end != start && end <= dn->dn_maxblkid &&
P2PHASE(off+len, dn->dn_datablksz)) {
err = dmu_tx_check_ioerr(zio, dn, 0, end);
if (err)
goto out;
}
/* level-1 blocks */
if (nlvls > 1) {
int shft = dn->dn_indblkshift - SPA_BLKPTRSHIFT;
for (i = (start>>shft)+1; i < end>>shft; i++) {
err = dmu_tx_check_ioerr(zio, dn, 1, i);
if (err)
goto out;
}
}
err = zio_wait(zio);
if (err)
goto out;
delta = P2NPHASE(off, dn->dn_datablksz);
}
min_ibs = max_ibs = dn->dn_indblkshift;
if (dn->dn_maxblkid > 0) {
/*
* The blocksize can't change,
* so we can make a more precise estimate.
*/
ASSERT(dn->dn_datablkshift != 0);
min_bs = max_bs = dn->dn_datablkshift;
} else {
/*
* The blocksize can increase up to the recordsize,
* or if it is already more than the recordsize,
* up to the next power of 2.
*/
min_bs = highbit64(dn->dn_datablksz - 1);
max_bs = MAX(max_bs, highbit64(dn->dn_datablksz - 1));
}
/*
* If this write is not off the end of the file
* we need to account for overwrites/unref.
*/
if (start <= dn->dn_maxblkid) {
for (l = 0; l < DN_MAX_LEVELS; l++)
history[l] = -1ULL;
}
while (start <= dn->dn_maxblkid) {
dmu_buf_impl_t *db;
rw_enter(&dn->dn_struct_rwlock, RW_READER);
err = dbuf_hold_impl(dn, 0, start,
FALSE, FALSE, FTAG, &db);
rw_exit(&dn->dn_struct_rwlock);
if (err) {
txh->txh_tx->tx_err = err;
return;
}
dmu_tx_count_twig(txh, dn, db, 0, start, B_FALSE,
history);
dbuf_rele(db, FTAG);
if (++start > end) {
/*
* Account for new indirects appearing
* before this IO gets assigned into a txg.
*/
bits = 64 - min_bs;
epbs = min_ibs - SPA_BLKPTRSHIFT;
for (bits -= epbs * (nlvls - 1);
bits >= 0; bits -= epbs) {
(void) refcount_add_many(
&txh->txh_fudge,
1ULL << max_ibs, FTAG);
}
goto out;
}
off += delta;
if (len >= delta)
len -= delta;
delta = dn->dn_datablksz;
}
}
/*
* 'end' is the last thing we will access, not one past.
* This way we won't overflow when accessing the last byte.
*/
start = P2ALIGN(off, 1ULL << max_bs);
end = P2ROUNDUP(off + len, 1ULL << max_bs) - 1;
(void) refcount_add_many(&txh->txh_space_towrite,
end - start + 1, FTAG);
start >>= min_bs;
end >>= min_bs;
epbs = min_ibs - SPA_BLKPTRSHIFT;
/*
* The object contains at most 2^(64 - min_bs) blocks,
* and each indirect level maps 2^epbs.
*/
for (bits = 64 - min_bs; bits >= 0; bits -= epbs) {
start >>= epbs;
end >>= epbs;
ASSERT3U(end, >=, start);
(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.
*/
(void) refcount_add_many(&txh->txh_space_towrite,
1ULL << max_ibs, FTAG);
}
}
out:
if (refcount_count(&txh->txh_space_towrite) +
refcount_count(&txh->txh_space_tooverwrite) >
2 * DMU_MAX_ACCESS)
err = SET_ERROR(EFBIG);
if (err)
txh->txh_tx->tx_err = err;
}
static void
dmu_tx_count_dnode(dmu_tx_hold_t *txh)
{
dnode_t *dn = txh->txh_dnode;
dnode_t *mdn = DMU_META_DNODE(txh->txh_tx->tx_objset);
uint64_t space = mdn->dn_datablksz +
((uint64_t)(mdn->dn_nlevels-1) << mdn->dn_indblkshift);
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)) {
(void) refcount_add_many(&txh->txh_space_tooverwrite,
space, FTAG);
(void) refcount_add_many(&txh->txh_space_tounref, space, FTAG);
} else {
(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);
}
}
}
void
dmu_tx_hold_write(dmu_tx_t *tx, uint64_t object, uint64_t off, int len)
{
dmu_tx_hold_t *txh;
ASSERT0(tx->tx_txg);
ASSERT3U(len, <=, DMU_MAX_ACCESS);
ASSERT(len == 0 || UINT64_MAX - off >= len - 1);
txh = dmu_tx_hold_object_impl(tx, tx->tx_objset,
object, THT_WRITE, off, len);
if (txh != NULL) {
dmu_tx_count_write(txh, off, len);
dmu_tx_count_dnode(txh);
}
}
void
dmu_tx_hold_write_by_dnode(dmu_tx_t *tx, dnode_t *dn, uint64_t off, int len)
{
dmu_tx_hold_t *txh;
ASSERT0(tx->tx_txg);
ASSERT3U(len, <=, DMU_MAX_ACCESS);
ASSERT(len == 0 || UINT64_MAX - off >= len - 1);
txh = dmu_tx_hold_dnode_impl(tx, dn, THT_WRITE, off, len);
if (txh != NULL) {
dmu_tx_count_write(txh, off, len);
dmu_tx_count_dnode(txh);
}
}
static void
dmu_tx_count_free(dmu_tx_hold_t *txh, uint64_t off, uint64_t len)
{
uint64_t blkid, nblks, lastblk;
uint64_t space = 0, unref = 0, skipped = 0;
dnode_t *dn = txh->txh_dnode;
dsl_dataset_t *ds = dn->dn_objset->os_dsl_dataset;
spa_t *spa = txh->txh_tx->tx_pool->dp_spa;
int epbs;
uint64_t l0span = 0, nl1blks = 0;
if (dn->dn_nlevels == 0)
return;
/*
* The struct_rwlock protects us against dn_nlevels
* changing, in case (against all odds) we manage to dirty &
* sync out the changes after we check for being dirty.
* Also, dbuf_hold_impl() wants us to have the struct_rwlock.
*/
rw_enter(&dn->dn_struct_rwlock, RW_READER);
epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT;
if (dn->dn_maxblkid == 0) {
if (off == 0 && len >= dn->dn_datablksz) {
blkid = 0;
nblks = 1;
} else {
rw_exit(&dn->dn_struct_rwlock);
return;
}
} else {
blkid = off >> dn->dn_datablkshift;
nblks = (len + dn->dn_datablksz - 1) >> dn->dn_datablkshift;
if (blkid > dn->dn_maxblkid) {
rw_exit(&dn->dn_struct_rwlock);
return;
}
if (blkid + nblks > dn->dn_maxblkid)
nblks = dn->dn_maxblkid - blkid + 1;
}
l0span = nblks; /* save for later use to calc level > 1 overhead */
if (dn->dn_nlevels == 1) {
int i;
for (i = 0; i < nblks; i++) {
blkptr_t *bp = dn->dn_phys->dn_blkptr;
ASSERT3U(blkid + i, <, dn->dn_nblkptr);
bp += blkid + i;
if (dsl_dataset_block_freeable(ds, bp, bp->blk_birth)) {
dprintf_bp(bp, "can free old%s", "");
space += bp_get_dsize(spa, bp);
}
unref += BP_GET_ASIZE(bp);
}
nl1blks = 1;
nblks = 0;
}
lastblk = blkid + nblks - 1;
while (nblks) {
dmu_buf_impl_t *dbuf;
uint64_t ibyte, new_blkid;
int epb = 1 << epbs;
int err, i, blkoff, tochk;
blkptr_t *bp;
ibyte = blkid << dn->dn_datablkshift;
err = dnode_next_offset(dn,
DNODE_FIND_HAVELOCK, &ibyte, 2, 1, 0);
new_blkid = ibyte >> dn->dn_datablkshift;
if (err == ESRCH) {
skipped += (lastblk >> epbs) - (blkid >> epbs) + 1;
break;
}
if (err) {
txh->txh_tx->tx_err = err;
break;
}
if (new_blkid > lastblk) {
skipped += (lastblk >> epbs) - (blkid >> epbs) + 1;
break;
}
if (new_blkid > blkid) {
ASSERT((new_blkid >> epbs) > (blkid >> epbs));
skipped += (new_blkid >> epbs) - (blkid >> epbs) - 1;
nblks -= new_blkid - blkid;
blkid = new_blkid;
}
blkoff = P2PHASE(blkid, epb);
tochk = MIN(epb - blkoff, nblks);
err = dbuf_hold_impl(dn, 1, blkid >> epbs,
FALSE, FALSE, FTAG, &dbuf);
if (err) {
txh->txh_tx->tx_err = err;
break;
}
(void) refcount_add_many(&txh->txh_memory_tohold,
dbuf->db.db_size, FTAG);
/*
* We don't check memory_tohold against DMU_MAX_ACCESS because
* memory_tohold is an over-estimation (especially the >L1
* indirect blocks), so it could fail. Callers should have
* already verified that they will not be holding too much
* memory.
*/
err = dbuf_read(dbuf, NULL, DB_RF_HAVESTRUCT | DB_RF_CANFAIL);
if (err != 0) {
txh->txh_tx->tx_err = err;
dbuf_rele(dbuf, FTAG);
break;
}
bp = dbuf->db.db_data;
bp += blkoff;
for (i = 0; i < tochk; i++) {
if (dsl_dataset_block_freeable(ds, &bp[i],
bp[i].blk_birth)) {
dprintf_bp(&bp[i], "can free old%s", "");
space += bp_get_dsize(spa, &bp[i]);
}
unref += BP_GET_ASIZE(bp);
}
dbuf_rele(dbuf, FTAG);
++nl1blks;
blkid += tochk;
nblks -= tochk;
}
rw_exit(&dn->dn_struct_rwlock);
/*
* Add in memory requirements of higher-level indirects.
* This assumes a worst-possible scenario for dn_nlevels and a
* worst-possible distribution of l1-blocks over the region to free.
*/
{
uint64_t blkcnt = 1 + ((l0span >> epbs) >> epbs);
int level = 2;
/*
* Here we don't use DN_MAX_LEVEL, but calculate it with the
* given datablkshift and indblkshift. This makes the
* difference between 19 and 8 on large files.
*/
int maxlevel = 2 + (DN_MAX_OFFSET_SHIFT - dn->dn_datablkshift) /
(dn->dn_indblkshift - SPA_BLKPTRSHIFT);
while (level++ < maxlevel) {
(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) {
(void) refcount_add_many(&txh->txh_fudge,
skipped << dn->dn_indblkshift, FTAG);
skipped = MIN(skipped, DMU_MAX_DELETEBLKCNT >> epbs);
(void) refcount_add_many(&txh->txh_memory_tohold,
skipped << dn->dn_indblkshift, FTAG);
}
(void) refcount_add_many(&txh->txh_space_tofree, space, FTAG);
(void) refcount_add_many(&txh->txh_space_tounref, unref, FTAG);
}
/*
* This function marks the transaction as being a "net free". The end
* result is that refquotas will be disabled for this transaction, and
* this transaction will be able to use half of the pool space overhead
* (see dsl_pool_adjustedsize()). Therefore this function should only
* be called for transactions that we expect will not cause a net increase
* in the amount of space used (but it's OK if that is occasionally not true).
*/
void
dmu_tx_mark_netfree(dmu_tx_t *tx)
{
dmu_tx_hold_t *txh;
txh = dmu_tx_hold_object_impl(tx, tx->tx_objset,
DMU_NEW_OBJECT, THT_FREE, 0, 0);
/*
* Pretend that this operation will free 1GB of space. This
* should be large enough to cancel out the largest write.
* We don't want to use something like UINT64_MAX, because that would
* cause overflows when doing math with these values (e.g. in
* dmu_tx_try_assign()).
*/
(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
dmu_tx_hold_free_impl(dmu_tx_hold_t *txh, uint64_t off, uint64_t len)
{
dmu_tx_t *tx;
dnode_t *dn;
int err;
zio_t *zio;
tx = txh->txh_tx;
ASSERT(tx->tx_txg == 0);
dn = txh->txh_dnode;
dmu_tx_count_dnode(txh);
if (off >= (dn->dn_maxblkid+1) * dn->dn_datablksz)
return;
if (len == DMU_OBJECT_END)
len = (dn->dn_maxblkid+1) * dn->dn_datablksz - off;
dmu_tx_count_dnode(txh);
/*
* For i/o error checking, we read the first and last level-0
* blocks if they are not aligned, and all the level-1 blocks.
*
* Note: dbuf_free_range() assumes that we have not instantiated
* any level-0 dbufs that will be completely freed. Therefore we must
* exercise care to not read or count the first and last blocks
* if they are blocksize-aligned.
*/
if (dn->dn_datablkshift == 0) {
if (off != 0 || len < dn->dn_datablksz)
dmu_tx_count_write(txh, 0, dn->dn_datablksz);
} else {
/* first block will be modified if it is not aligned */
if (!IS_P2ALIGNED(off, 1 << dn->dn_datablkshift))
dmu_tx_count_write(txh, off, 1);
/* last block will be modified if it is not aligned */
if (!IS_P2ALIGNED(off + len, 1 << dn->dn_datablkshift))
dmu_tx_count_write(txh, off+len, 1);
}
/*
* Check level-1 blocks.
*/
if (dn->dn_nlevels > 1) {
int shift = dn->dn_datablkshift + dn->dn_indblkshift -
SPA_BLKPTRSHIFT;
uint64_t start = off >> shift;
uint64_t end = (off + len) >> shift;
uint64_t i;
ASSERT(dn->dn_indblkshift != 0);
/*
* dnode_reallocate() can result in an object with indirect
* blocks having an odd data block size. In this case,
* just check the single block.
*/
if (dn->dn_datablkshift == 0)
start = end = 0;
zio = zio_root(tx->tx_pool->dp_spa,
NULL, NULL, ZIO_FLAG_CANFAIL);
for (i = start; i <= end; i++) {
uint64_t ibyte = i << shift;
err = dnode_next_offset(dn, 0, &ibyte, 2, 1, 0);
i = ibyte >> shift;
if (err == ESRCH || i > end)
break;
if (err) {
tx->tx_err = err;
return;
}
err = dmu_tx_check_ioerr(zio, dn, 1, i);
if (err) {
tx->tx_err = err;
return;
}
}
err = zio_wait(zio);
if (err) {
tx->tx_err = err;
return;
}
}
dmu_tx_count_free(txh, off, len);
}
void
dmu_tx_hold_free(dmu_tx_t *tx, uint64_t object, uint64_t off, uint64_t len)
{
dmu_tx_hold_t *txh;
txh = dmu_tx_hold_object_impl(tx, tx->tx_objset,
object, THT_FREE, off, len);
if (txh != NULL)
(void) dmu_tx_hold_free_impl(txh, off, len);
}
void
dmu_tx_hold_free_by_dnode(dmu_tx_t *tx, dnode_t *dn, uint64_t off, uint64_t len)
{
dmu_tx_hold_t *txh;
txh = dmu_tx_hold_dnode_impl(tx, dn, THT_FREE, off, len);
if (txh != NULL)
(void) dmu_tx_hold_free_impl(txh, off, len);
}
static void
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;
int lvl;
ASSERT(tx->tx_txg == 0);
dn = txh->txh_dnode;
dmu_tx_count_dnode(txh);
if (dn == NULL) {
/*
* We will be able to fit a new object's entries into one leaf
* block. So there will be at most 2 blocks total,
* including the header block.
*/
dmu_tx_count_write(txh, 0, 2ULL << fzap_default_block_shift);
return;
}
ASSERT3U(DMU_OT_BYTESWAP(dn->dn_type), ==, DMU_BSWAP_ZAP);
if (dn->dn_maxblkid == 0 && !add) {
blkptr_t *bp;
/*
* If there is only one block (i.e. this is a micro-zap)
* and we are not adding anything, the accounting is simple.
*/
err = dmu_tx_check_ioerr(NULL, dn, 0, 0);
if (err) {
tx->tx_err = err;
return;
}
/*
* Use max block size here, since we don't know how much
* the size will change between now and the dbuf dirty call.
*/
bp = &dn->dn_phys->dn_blkptr[0];
if (dsl_dataset_block_freeable(dn->dn_objset->os_dsl_dataset,
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;
}
if (dn->dn_maxblkid > 0 && name) {
/*
* access the name in this fat-zap so that we'll check
* for i/o errors to the leaf blocks, etc.
*/
err = zap_lookup_by_dnode(dn, name, 8, 0, NULL);
if (err == EIO) {
tx->tx_err = err;
return;
}
}
err = zap_count_write_by_dnode(dn, name, add,
&txh->txh_space_towrite, &txh->txh_space_tooverwrite);
/*
* If the modified blocks are scattered to the four winds,
* 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 (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
dmu_tx_hold_zap(dmu_tx_t *tx, uint64_t object, int add, const char *name)
{
dmu_tx_hold_t *txh;
ASSERT0(tx->tx_txg);
txh = dmu_tx_hold_object_impl(tx, tx->tx_objset,
object, THT_ZAP, add, (uintptr_t)name);
if (txh != NULL)
dmu_tx_hold_zap_impl(txh, add, name);
}
void
dmu_tx_hold_zap_by_dnode(dmu_tx_t *tx, dnode_t *dn, int add, const char *name)
{
dmu_tx_hold_t *txh;
ASSERT0(tx->tx_txg);
ASSERT(dn != NULL);
txh = dmu_tx_hold_dnode_impl(tx, dn, THT_ZAP, add, (uintptr_t)name);
if (txh != NULL)
dmu_tx_hold_zap_impl(txh, add, name);
}
void
dmu_tx_hold_bonus(dmu_tx_t *tx, uint64_t object)
{
dmu_tx_hold_t *txh;
ASSERT(tx->tx_txg == 0);
txh = dmu_tx_hold_object_impl(tx, tx->tx_objset,
object, THT_BONUS, 0, 0);
if (txh)
dmu_tx_count_dnode(txh);
}
void
dmu_tx_hold_bonus_by_dnode(dmu_tx_t *tx, dnode_t *dn)
{
dmu_tx_hold_t *txh;
ASSERT0(tx->tx_txg);
txh = dmu_tx_hold_dnode_impl(tx, dn, THT_BONUS, 0, 0);
if (txh)
dmu_tx_count_dnode(txh);
}
void
dmu_tx_hold_space(dmu_tx_t *tx, uint64_t space)
{
dmu_tx_hold_t *txh;
ASSERT(tx->tx_txg == 0);
txh = dmu_tx_hold_object_impl(tx, tx->tx_objset,
DMU_NEW_OBJECT, THT_SPACE, space, 0);
if (txh)
(void) refcount_add_many(&txh->txh_space_towrite, space, FTAG);
}
int
dmu_tx_holds(dmu_tx_t *tx, uint64_t object)
{
dmu_tx_hold_t *txh;
int holds = 0;
/*
* By asserting that the tx is assigned, we're counting the
* number of dn_tx_holds, which is the same as the number of
* dn_holds. Otherwise, we'd be counting dn_holds, but
* dn_tx_holds could be 0.
*/
ASSERT(tx->tx_txg != 0);
/* if (tx->tx_anyobj == TRUE) */
/* return (0); */
for (txh = list_head(&tx->tx_holds); txh;
txh = list_next(&tx->tx_holds, txh)) {
if (txh->txh_dnode && txh->txh_dnode->dn_object == object)
holds++;
}
return (holds);
}
#ifdef DEBUG_DMU_TX
void
dmu_tx_dirty_buf(dmu_tx_t *tx, dmu_buf_impl_t *db)
{
dmu_tx_hold_t *txh;
int match_object = FALSE, match_offset = FALSE;
dnode_t *dn;
DB_DNODE_ENTER(db);
dn = DB_DNODE(db);
ASSERT(dn != NULL);
ASSERT(tx->tx_txg != 0);
ASSERT(tx->tx_objset == NULL || dn->dn_objset == tx->tx_objset);
ASSERT3U(dn->dn_object, ==, db->db.db_object);
if (tx->tx_anyobj) {
DB_DNODE_EXIT(db);
return;
}
/* XXX No checking on the meta dnode for now */
if (db->db.db_object == DMU_META_DNODE_OBJECT) {
DB_DNODE_EXIT(db);
return;
}
for (txh = list_head(&tx->tx_holds); txh;
txh = list_next(&tx->tx_holds, txh)) {
ASSERT3U(dn->dn_assigned_txg, ==, tx->tx_txg);
if (txh->txh_dnode == dn && txh->txh_type != THT_NEWOBJECT)
match_object = TRUE;
if (txh->txh_dnode == NULL || txh->txh_dnode == dn) {
int datablkshift = dn->dn_datablkshift ?
dn->dn_datablkshift : SPA_MAXBLOCKSHIFT;
int epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT;
int shift = datablkshift + epbs * db->db_level;
uint64_t beginblk = shift >= 64 ? 0 :
(txh->txh_arg1 >> shift);
uint64_t endblk = shift >= 64 ? 0 :
((txh->txh_arg1 + txh->txh_arg2 - 1) >> shift);
uint64_t blkid = db->db_blkid;
/* XXX txh_arg2 better not be zero... */
dprintf("found txh type %x beginblk=%llx endblk=%llx\n",
txh->txh_type, beginblk, endblk);
switch (txh->txh_type) {
case THT_WRITE:
if (blkid >= beginblk && blkid <= endblk)
match_offset = TRUE;
/*
* We will let this hold work for the bonus
* or spill buffer so that we don't need to
* hold it when creating a new object.
*/
if (blkid == DMU_BONUS_BLKID ||
blkid == DMU_SPILL_BLKID)
match_offset = TRUE;
/*
* They might have to increase nlevels,
* thus dirtying the new TLIBs. Or the
* might have to change the block size,
* thus dirying the new lvl=0 blk=0.
*/
if (blkid == 0)
match_offset = TRUE;
break;
case THT_FREE:
/*
* We will dirty all the level 1 blocks in
* the free range and perhaps the first and
* last level 0 block.
*/
if (blkid >= beginblk && (blkid <= endblk ||
txh->txh_arg2 == DMU_OBJECT_END))
match_offset = TRUE;
break;
case THT_SPILL:
if (blkid == DMU_SPILL_BLKID)
match_offset = TRUE;
break;
case THT_BONUS:
if (blkid == DMU_BONUS_BLKID)
match_offset = TRUE;
break;
case THT_ZAP:
match_offset = TRUE;
break;
case THT_NEWOBJECT:
match_object = TRUE;
break;
default:
cmn_err(CE_PANIC, "bad txh_type %d",
txh->txh_type);
}
}
if (match_object && match_offset) {
DB_DNODE_EXIT(db);
return;
}
}
DB_DNODE_EXIT(db);
panic("dirtying dbuf obj=%llx lvl=%u blkid=%llx but not tx_held\n",
(u_longlong_t)db->db.db_object, db->db_level,
(u_longlong_t)db->db_blkid);
}
#endif
/*
* If we can't do 10 iops, something is wrong. Let us go ahead
* and hit zfs_dirty_data_max.
*/
hrtime_t zfs_delay_max_ns = 100 * MICROSEC; /* 100 milliseconds */
int zfs_delay_resolution_ns = 100 * 1000; /* 100 microseconds */
/*
* We delay transactions when we've determined that the backend storage
* isn't able to accommodate the rate of incoming writes.
*
* If there is already a transaction waiting, we delay relative to when
* that transaction finishes waiting. This way the calculated min_time
* is independent of the number of threads concurrently executing
* transactions.
*
* If we are the only waiter, wait relative to when the transaction
* started, rather than the current time. This credits the transaction for
* "time already served", e.g. reading indirect blocks.
*
* The minimum time for a transaction to take is calculated as:
* min_time = scale * (dirty - min) / (max - dirty)
* min_time is then capped at zfs_delay_max_ns.
*
* The delay has two degrees of freedom that can be adjusted via tunables.
* The percentage of dirty data at which we start to delay is defined by
* zfs_delay_min_dirty_percent. This should typically be at or above
* zfs_vdev_async_write_active_max_dirty_percent so that we only start to
* delay after writing at full speed has failed to keep up with the incoming
* write rate. The scale of the curve is defined by zfs_delay_scale. Roughly
* speaking, this variable determines the amount of delay at the midpoint of
* the curve.
*
* delay
* 10ms +-------------------------------------------------------------*+
* | *|
* 9ms + *+
* | *|
* 8ms + *+
* | * |
* 7ms + * +
* | * |
* 6ms + * +
* | * |
* 5ms + * +
* | * |
* 4ms + * +
* | * |
* 3ms + * +
* | * |
* 2ms + (midpoint) * +
* | | ** |
* 1ms + v *** +
* | zfs_delay_scale ----------> ******** |
* 0 +-------------------------------------*********----------------+
* 0% <- zfs_dirty_data_max -> 100%
*
* Note that since the delay is added to the outstanding time remaining on the
* most recent transaction, the delay is effectively the inverse of IOPS.
* Here the midpoint of 500us translates to 2000 IOPS. The shape of the curve
* was chosen such that small changes in the amount of accumulated dirty data
* in the first 3/4 of the curve yield relatively small differences in the
* amount of delay.
*
* The effects can be easier to understand when the amount of delay is
* represented on a log scale:
*
* delay
* 100ms +-------------------------------------------------------------++
* + +
* | |
* + *+
* 10ms + *+
* + ** +
* | (midpoint) ** |
* + | ** +
* 1ms + v **** +
* + zfs_delay_scale ----------> ***** +
* | **** |
* + **** +
* 100us + ** +
* + * +
* | * |
* + * +
* 10us + * +
* + +
* | |
* + +
* +--------------------------------------------------------------+
* 0% <- zfs_dirty_data_max -> 100%
*
* Note here that only as the amount of dirty data approaches its limit does
* the delay start to increase rapidly. The goal of a properly tuned system
* should be to keep the amount of dirty data out of that range by first
* ensuring that the appropriate limits are set for the I/O scheduler to reach
* optimal throughput on the backend storage, and then by changing the value
* of zfs_delay_scale to increase the steepness of the curve.
*/
static void
dmu_tx_delay(dmu_tx_t *tx, uint64_t dirty)
{
dsl_pool_t *dp = tx->tx_pool;
uint64_t delay_min_bytes =
zfs_dirty_data_max * zfs_delay_min_dirty_percent / 100;
hrtime_t wakeup, min_tx_time, now;
if (dirty <= delay_min_bytes)
return;
/*
* The caller has already waited until we are under the max.
* We make them pass us the amount of dirty data so we don't
* have to handle the case of it being >= the max, which could
* cause a divide-by-zero if it's == the max.
*/
ASSERT3U(dirty, <, zfs_dirty_data_max);
now = gethrtime();
min_tx_time = zfs_delay_scale *
(dirty - delay_min_bytes) / (zfs_dirty_data_max - dirty);
min_tx_time = MIN(min_tx_time, zfs_delay_max_ns);
if (now > tx->tx_start + min_tx_time)
return;
DTRACE_PROBE3(delay__mintime, dmu_tx_t *, tx, uint64_t, dirty,
uint64_t, min_tx_time);
mutex_enter(&dp->dp_lock);
wakeup = MAX(tx->tx_start + min_tx_time,
dp->dp_last_wakeup + min_tx_time);
dp->dp_last_wakeup = wakeup;
mutex_exit(&dp->dp_lock);
zfs_sleep_until(wakeup);
}
static int
dmu_tx_try_assign(dmu_tx_t *tx, txg_how_t txg_how)
{
dmu_tx_hold_t *txh;
spa_t *spa = tx->tx_pool->dp_spa;
uint64_t memory, asize, fsize, usize;
uint64_t towrite, tofree, tooverwrite, tounref, tohold, fudge;
ASSERT0(tx->tx_txg);
if (tx->tx_err) {
DMU_TX_STAT_BUMP(dmu_tx_error);
return (tx->tx_err);
}
if (spa_suspended(spa)) {
DMU_TX_STAT_BUMP(dmu_tx_suspended);
/*
* If the user has indicated a blocking failure mode
* then return ERESTART which will block in dmu_tx_wait().
* Otherwise, return EIO so that an error can get
* propagated back to the VOP calls.
*
* Note that we always honor the txg_how flag regardless
* of the failuremode setting.
*/
if (spa_get_failmode(spa) == ZIO_FAILURE_MODE_CONTINUE &&
txg_how != TXG_WAIT)
return (SET_ERROR(EIO));
return (SET_ERROR(ERESTART));
}
if (!tx->tx_waited &&
dsl_pool_need_dirty_delay(tx->tx_pool)) {
tx->tx_wait_dirty = B_TRUE;
DMU_TX_STAT_BUMP(dmu_tx_dirty_delay);
return (ERESTART);
}
tx->tx_txg = txg_hold_open(tx->tx_pool, &tx->tx_txgh);
tx->tx_needassign_txh = NULL;
/*
* NB: No error returns are allowed after txg_hold_open, but
* before processing the dnode holds, due to the
* dmu_tx_unassign() logic.
*/
towrite = tofree = tooverwrite = tounref = tohold = fudge = 0;
for (txh = list_head(&tx->tx_holds); txh;
txh = list_next(&tx->tx_holds, txh)) {
dnode_t *dn = txh->txh_dnode;
if (dn != NULL) {
mutex_enter(&dn->dn_mtx);
if (dn->dn_assigned_txg == tx->tx_txg - 1) {
mutex_exit(&dn->dn_mtx);
tx->tx_needassign_txh = txh;
DMU_TX_STAT_BUMP(dmu_tx_group);
return (SET_ERROR(ERESTART));
}
if (dn->dn_assigned_txg == 0)
dn->dn_assigned_txg = tx->tx_txg;
ASSERT3U(dn->dn_assigned_txg, ==, tx->tx_txg);
(void) refcount_add(&dn->dn_tx_holds, tx);
mutex_exit(&dn->dn_mtx);
}
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);
}
/*
* If a snapshot has been taken since we made our estimates,
* assume that we won't be able to free or overwrite anything.
*/
if (tx->tx_objset &&
dsl_dataset_prev_snap_txg(tx->tx_objset->os_dsl_dataset) >
tx->tx_lastsnap_txg) {
towrite += tooverwrite;
tooverwrite = tofree = 0;
}
/* needed allocation: worst-case estimate of write space */
asize = spa_get_asize(tx->tx_pool->dp_spa, towrite + tooverwrite);
/* freed space estimate: worst-case overwrite + free estimate */
fsize = spa_get_asize(tx->tx_pool->dp_spa, tooverwrite) + tofree;
/* convert unrefd space to worst-case estimate */
usize = spa_get_asize(tx->tx_pool->dp_spa, tounref);
/* calculate memory footprint estimate */
memory = towrite + tooverwrite + tohold;
#ifdef DEBUG_DMU_TX
/*
* Add in 'tohold' to account for our dirty holds on this memory
* XXX - the "fudge" factor is to account for skipped blocks that
* we missed because dnode_next_offset() misses in-core-only blocks.
*/
tx->tx_space_towrite = asize +
spa_get_asize(tx->tx_pool->dp_spa, tohold + fudge);
tx->tx_space_tofree = tofree;
tx->tx_space_tooverwrite = tooverwrite;
tx->tx_space_tounref = tounref;
#endif
if (tx->tx_dir && asize != 0) {
int err = dsl_dir_tempreserve_space(tx->tx_dir, memory,
asize, fsize, usize, &tx->tx_tempreserve_cookie, tx);
if (err)
return (err);
}
DMU_TX_STAT_BUMP(dmu_tx_assigned);
return (0);
}
static void
dmu_tx_unassign(dmu_tx_t *tx)
{
dmu_tx_hold_t *txh;
if (tx->tx_txg == 0)
return;
txg_rele_to_quiesce(&tx->tx_txgh);
/*
* Walk the transaction's hold list, removing the hold on the
* associated dnode, and notifying waiters if the refcount drops to 0.
*/
for (txh = list_head(&tx->tx_holds);
txh && txh != tx->tx_needassign_txh;
txh = list_next(&tx->tx_holds, txh)) {
dnode_t *dn = txh->txh_dnode;
if (dn == NULL)
continue;
mutex_enter(&dn->dn_mtx);
ASSERT3U(dn->dn_assigned_txg, ==, tx->tx_txg);
if (refcount_remove(&dn->dn_tx_holds, tx) == 0) {
dn->dn_assigned_txg = 0;
cv_broadcast(&dn->dn_notxholds);
}
mutex_exit(&dn->dn_mtx);
}
txg_rele_to_sync(&tx->tx_txgh);
tx->tx_lasttried_txg = tx->tx_txg;
tx->tx_txg = 0;
}
/*
* Assign tx to a transaction group. txg_how can be one of:
*
* (1) TXG_WAIT. If the current open txg is full, waits until there's
* a new one. This should be used when you're not holding locks.
* It will only fail if we're truly out of space (or over quota).
*
* (2) TXG_NOWAIT. If we can't assign into the current open txg without
* blocking, returns immediately with ERESTART. This should be used
* whenever you're holding locks. On an ERESTART error, the caller
* should drop locks, do a dmu_tx_wait(tx), and try again.
*
* (3) TXG_WAITED. Like TXG_NOWAIT, but indicates that dmu_tx_wait()
* has already been called on behalf of this operation (though
* most likely on a different tx).
*/
int
dmu_tx_assign(dmu_tx_t *tx, txg_how_t txg_how)
{
int err;
ASSERT(tx->tx_txg == 0);
ASSERT(txg_how == TXG_WAIT || txg_how == TXG_NOWAIT ||
txg_how == TXG_WAITED);
ASSERT(!dsl_pool_sync_context(tx->tx_pool));
if (txg_how == TXG_WAITED)
tx->tx_waited = B_TRUE;
/* If we might wait, we must not hold the config lock. */
ASSERT(txg_how != TXG_WAIT || !dsl_pool_config_held(tx->tx_pool));
while ((err = dmu_tx_try_assign(tx, txg_how)) != 0) {
dmu_tx_unassign(tx);
if (err != ERESTART || txg_how != TXG_WAIT)
return (err);
dmu_tx_wait(tx);
}
txg_rele_to_quiesce(&tx->tx_txgh);
return (0);
}
void
dmu_tx_wait(dmu_tx_t *tx)
{
spa_t *spa = tx->tx_pool->dp_spa;
dsl_pool_t *dp = tx->tx_pool;
hrtime_t before;
ASSERT(tx->tx_txg == 0);
ASSERT(!dsl_pool_config_held(tx->tx_pool));
before = gethrtime();
if (tx->tx_wait_dirty) {
uint64_t dirty;
/*
* dmu_tx_try_assign() has determined that we need to wait
* because we've consumed much or all of the dirty buffer
* space.
*/
mutex_enter(&dp->dp_lock);
if (dp->dp_dirty_total >= zfs_dirty_data_max)
DMU_TX_STAT_BUMP(dmu_tx_dirty_over_max);
while (dp->dp_dirty_total >= zfs_dirty_data_max)
cv_wait(&dp->dp_spaceavail_cv, &dp->dp_lock);
dirty = dp->dp_dirty_total;
mutex_exit(&dp->dp_lock);
dmu_tx_delay(tx, dirty);
tx->tx_wait_dirty = B_FALSE;
/*
* Note: setting tx_waited only has effect if the caller
* used TX_WAIT. Otherwise they are going to destroy
* this tx and try again. The common case, zfs_write(),
* uses TX_WAIT.
*/
tx->tx_waited = B_TRUE;
} else if (spa_suspended(spa) || tx->tx_lasttried_txg == 0) {
/*
* If the pool is suspended we need to wait until it
* is resumed. Note that it's possible that the pool
* has become active after this thread has tried to
* obtain a tx. If that's the case then tx_lasttried_txg
* would not have been set.
*/
txg_wait_synced(dp, spa_last_synced_txg(spa) + 1);
} else if (tx->tx_needassign_txh) {
dnode_t *dn = tx->tx_needassign_txh->txh_dnode;
mutex_enter(&dn->dn_mtx);
while (dn->dn_assigned_txg == tx->tx_lasttried_txg - 1)
cv_wait(&dn->dn_notxholds, &dn->dn_mtx);
mutex_exit(&dn->dn_mtx);
tx->tx_needassign_txh = NULL;
} else {
/*
* A dnode is assigned to the quiescing txg. Wait for its
* transaction to complete.
*/
txg_wait_open(tx->tx_pool, tx->tx_lasttried_txg + 1);
}
spa_tx_assign_add_nsecs(spa, gethrtime() - before);
}
void
dmu_tx_willuse_space(dmu_tx_t *tx, int64_t delta)
{
#ifdef DEBUG_DMU_TX
if (tx->tx_dir == NULL || delta == 0)
return;
if (delta > 0) {
ASSERT3U(refcount_count(&tx->tx_space_written) + delta, <=,
tx->tx_space_towrite);
(void) refcount_add_many(&tx->tx_space_written, delta, NULL);
} else {
(void) refcount_add_many(&tx->tx_space_freed, -delta, NULL);
}
#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)
{
dmu_tx_hold_t *txh;
ASSERT(tx->tx_txg != 0);
/*
* Go through the transaction's hold list and remove holds on
* associated dnodes, notifying waiters if no holds remain.
*/
for (txh = list_head(&tx->tx_holds); txh != NULL;
txh = list_next(&tx->tx_holds, txh)) {
dnode_t *dn = txh->txh_dnode;
if (dn == NULL)
continue;
mutex_enter(&dn->dn_mtx);
ASSERT3U(dn->dn_assigned_txg, ==, tx->tx_txg);
if (refcount_remove(&dn->dn_tx_holds, tx) == 0) {
dn->dn_assigned_txg = 0;
cv_broadcast(&dn->dn_notxholds);
}
mutex_exit(&dn->dn_mtx);
}
if (tx->tx_tempreserve_cookie)
dsl_dir_tempreserve_clear(tx->tx_tempreserve_cookie, tx);
if (!list_is_empty(&tx->tx_callbacks))
txg_register_callbacks(&tx->tx_txgh, &tx->tx_callbacks);
if (tx->tx_anyobj == FALSE)
txg_rele_to_sync(&tx->tx_txgh);
#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));
#endif
dmu_tx_destroy(tx);
}
void
dmu_tx_abort(dmu_tx_t *tx)
{
ASSERT(tx->tx_txg == 0);
/*
* Call any registered callbacks with an error code.
*/
if (!list_is_empty(&tx->tx_callbacks))
dmu_tx_do_callbacks(&tx->tx_callbacks, ECANCELED);
dmu_tx_destroy(tx);
}
uint64_t
dmu_tx_get_txg(dmu_tx_t *tx)
{
ASSERT(tx->tx_txg != 0);
return (tx->tx_txg);
}
dsl_pool_t *
dmu_tx_pool(dmu_tx_t *tx)
{
ASSERT(tx->tx_pool != NULL);
return (tx->tx_pool);
}
void
dmu_tx_callback_register(dmu_tx_t *tx, dmu_tx_callback_func_t *func, void *data)
{
dmu_tx_callback_t *dcb;
dcb = kmem_alloc(sizeof (dmu_tx_callback_t), KM_SLEEP);
dcb->dcb_func = func;
dcb->dcb_data = data;
list_insert_tail(&tx->tx_callbacks, dcb);
}
/*
* Call all the commit callbacks on a list, with a given error code.
*/
void
dmu_tx_do_callbacks(list_t *cb_list, int error)
{
dmu_tx_callback_t *dcb;
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));
}
}
/*
* Interface to hold a bunch of attributes.
* used for creating new files.
* attrsize is the total size of all attributes
* to be added during object creation
*
* For updating/adding a single attribute dmu_tx_hold_sa() should be used.
*/
/*
* hold necessary attribute name for attribute registration.
* should be a very rare case where this is needed. If it does
* happen it would only happen on the first write to the file system.
*/
static void
dmu_tx_sa_registration_hold(sa_os_t *sa, dmu_tx_t *tx)
{
int i;
if (!sa->sa_need_attr_registration)
return;
for (i = 0; i != sa->sa_num_attrs; i++) {
if (!sa->sa_attr_table[i].sa_registered) {
if (sa->sa_reg_attr_obj)
dmu_tx_hold_zap(tx, sa->sa_reg_attr_obj,
B_TRUE, sa->sa_attr_table[i].sa_name);
else
dmu_tx_hold_zap(tx, DMU_NEW_OBJECT,
B_TRUE, sa->sa_attr_table[i].sa_name);
}
}
}
void
dmu_tx_hold_spill(dmu_tx_t *tx, uint64_t object)
{
dnode_t *dn;
dmu_tx_hold_t *txh;
txh = dmu_tx_hold_object_impl(tx, tx->tx_objset, object,
THT_SPILL, 0, 0);
if (txh == NULL)
return;
dn = txh->txh_dnode;
if (dn == NULL)
return;
/* If blkptr doesn't exist then add space to towrite */
if (!(dn->dn_phys->dn_flags & DNODE_FLAG_SPILL_BLKPTR)) {
(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)) {
(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);
}
}
}
void
dmu_tx_hold_sa_create(dmu_tx_t *tx, int attrsize)
{
sa_os_t *sa = tx->tx_objset->os_sa;
dmu_tx_hold_bonus(tx, DMU_NEW_OBJECT);
if (tx->tx_objset->os_sa->sa_master_obj == 0)
return;
if (tx->tx_objset->os_sa->sa_layout_attr_obj)
dmu_tx_hold_zap(tx, sa->sa_layout_attr_obj, B_TRUE, NULL);
else {
dmu_tx_hold_zap(tx, sa->sa_master_obj, B_TRUE, SA_LAYOUTS);
dmu_tx_hold_zap(tx, sa->sa_master_obj, B_TRUE, SA_REGISTRY);
dmu_tx_hold_zap(tx, DMU_NEW_OBJECT, B_TRUE, NULL);
dmu_tx_hold_zap(tx, DMU_NEW_OBJECT, B_TRUE, NULL);
}
dmu_tx_sa_registration_hold(sa, tx);
if (attrsize <= DN_OLD_MAX_BONUSLEN && !sa->sa_force_spill)
return;
(void) dmu_tx_hold_object_impl(tx, tx->tx_objset, DMU_NEW_OBJECT,
THT_SPILL, 0, 0);
}
/*
* Hold SA attribute
*
* dmu_tx_hold_sa(dmu_tx_t *tx, sa_handle_t *, attribute, add, size)
*
* variable_size is the total size of all variable sized attributes
* passed to this function. It is not the total size of all
* variable size attributes that *may* exist on this object.
*/
void
dmu_tx_hold_sa(dmu_tx_t *tx, sa_handle_t *hdl, boolean_t may_grow)
{
uint64_t object;
sa_os_t *sa = tx->tx_objset->os_sa;
ASSERT(hdl != NULL);
object = sa_handle_object(hdl);
dmu_tx_hold_bonus(tx, object);
if (tx->tx_objset->os_sa->sa_master_obj == 0)
return;
if (tx->tx_objset->os_sa->sa_reg_attr_obj == 0 ||
tx->tx_objset->os_sa->sa_layout_attr_obj == 0) {
dmu_tx_hold_zap(tx, sa->sa_master_obj, B_TRUE, SA_LAYOUTS);
dmu_tx_hold_zap(tx, sa->sa_master_obj, B_TRUE, SA_REGISTRY);
dmu_tx_hold_zap(tx, DMU_NEW_OBJECT, B_TRUE, NULL);
dmu_tx_hold_zap(tx, DMU_NEW_OBJECT, B_TRUE, NULL);
}
dmu_tx_sa_registration_hold(sa, tx);
if (may_grow && tx->tx_objset->os_sa->sa_layout_attr_obj)
dmu_tx_hold_zap(tx, sa->sa_layout_attr_obj, B_TRUE, NULL);
if (sa->sa_force_spill || may_grow || hdl->sa_spill) {
ASSERT(tx->tx_txg == 0);
dmu_tx_hold_spill(tx, object);
} else {
dmu_buf_impl_t *db = (dmu_buf_impl_t *)hdl->sa_bonus;
dnode_t *dn;
DB_DNODE_ENTER(db);
dn = DB_DNODE(db);
if (dn->dn_have_spill) {
ASSERT(tx->tx_txg == 0);
dmu_tx_hold_spill(tx, object);
}
DB_DNODE_EXIT(db);
}
}
void
dmu_tx_init(void)
{
dmu_tx_ksp = kstat_create("zfs", 0, "dmu_tx", "misc",
KSTAT_TYPE_NAMED, sizeof (dmu_tx_stats) / sizeof (kstat_named_t),
KSTAT_FLAG_VIRTUAL);
if (dmu_tx_ksp != NULL) {
dmu_tx_ksp->ks_data = &dmu_tx_stats;
kstat_install(dmu_tx_ksp);
}
}
void
dmu_tx_fini(void)
{
if (dmu_tx_ksp != NULL) {
kstat_delete(dmu_tx_ksp);
dmu_tx_ksp = NULL;
}
}
#if defined(_KERNEL) && defined(HAVE_SPL)
EXPORT_SYMBOL(dmu_tx_create);
EXPORT_SYMBOL(dmu_tx_hold_write);
EXPORT_SYMBOL(dmu_tx_hold_write_by_dnode);
EXPORT_SYMBOL(dmu_tx_hold_free);
EXPORT_SYMBOL(dmu_tx_hold_free_by_dnode);
EXPORT_SYMBOL(dmu_tx_hold_zap);
EXPORT_SYMBOL(dmu_tx_hold_zap_by_dnode);
EXPORT_SYMBOL(dmu_tx_hold_bonus);
EXPORT_SYMBOL(dmu_tx_hold_bonus_by_dnode);
EXPORT_SYMBOL(dmu_tx_abort);
EXPORT_SYMBOL(dmu_tx_assign);
EXPORT_SYMBOL(dmu_tx_wait);
EXPORT_SYMBOL(dmu_tx_commit);
EXPORT_SYMBOL(dmu_tx_get_txg);
EXPORT_SYMBOL(dmu_tx_callback_register);
EXPORT_SYMBOL(dmu_tx_do_callbacks);
EXPORT_SYMBOL(dmu_tx_hold_spill);
EXPORT_SYMBOL(dmu_tx_hold_sa_create);
EXPORT_SYMBOL(dmu_tx_hold_sa);
#endif
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