mirror_zfs/module/zfs/zil.c
Alexander Motin ad47eca195 ZIL: Assert record sizes in different places
This should make sure we have log written without overflows.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by:	Alexander Motin <mav@FreeBSD.org>
Sponsored by:	iXsystems, Inc.
Closes #15517
2024-01-08 16:11:39 -08:00

4254 lines
129 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 https://opensource.org/licenses/CDDL-1.0.
* 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) 2011, 2018 by Delphix. All rights reserved.
* Copyright (c) 2014 Integros [integros.com]
* Copyright (c) 2018 Datto Inc.
*/
/* Portions Copyright 2010 Robert Milkowski */
#include <sys/zfs_context.h>
#include <sys/spa.h>
#include <sys/spa_impl.h>
#include <sys/dmu.h>
#include <sys/zap.h>
#include <sys/arc.h>
#include <sys/stat.h>
#include <sys/zil.h>
#include <sys/zil_impl.h>
#include <sys/dsl_dataset.h>
#include <sys/vdev_impl.h>
#include <sys/dmu_tx.h>
#include <sys/dsl_pool.h>
#include <sys/metaslab.h>
#include <sys/trace_zfs.h>
#include <sys/abd.h>
#include <sys/brt.h>
#include <sys/wmsum.h>
/*
* The ZFS Intent Log (ZIL) saves "transaction records" (itxs) of system
* calls that change the file system. Each itx has enough information to
* be able to replay them after a system crash, power loss, or
* equivalent failure mode. These are stored in memory until either:
*
* 1. they are committed to the pool by the DMU transaction group
* (txg), at which point they can be discarded; or
* 2. they are committed to the on-disk ZIL for the dataset being
* modified (e.g. due to an fsync, O_DSYNC, or other synchronous
* requirement).
*
* In the event of a crash or power loss, the itxs contained by each
* dataset's on-disk ZIL will be replayed when that dataset is first
* instantiated (e.g. if the dataset is a normal filesystem, when it is
* first mounted).
*
* As hinted at above, there is one ZIL per dataset (both the in-memory
* representation, and the on-disk representation). The on-disk format
* consists of 3 parts:
*
* - a single, per-dataset, ZIL header; which points to a chain of
* - zero or more ZIL blocks; each of which contains
* - zero or more ZIL records
*
* A ZIL record holds the information necessary to replay a single
* system call transaction. A ZIL block can hold many ZIL records, and
* the blocks are chained together, similarly to a singly linked list.
*
* Each ZIL block contains a block pointer (blkptr_t) to the next ZIL
* block in the chain, and the ZIL header points to the first block in
* the chain.
*
* Note, there is not a fixed place in the pool to hold these ZIL
* blocks; they are dynamically allocated and freed as needed from the
* blocks available on the pool, though they can be preferentially
* allocated from a dedicated "log" vdev.
*/
/*
* This controls the amount of time that a ZIL block (lwb) will remain
* "open" when it isn't "full", and it has a thread waiting for it to be
* committed to stable storage. Please refer to the zil_commit_waiter()
* function (and the comments within it) for more details.
*/
static uint_t zfs_commit_timeout_pct = 5;
/*
* Minimal time we care to delay commit waiting for more ZIL records.
* At least FreeBSD kernel can't sleep for less than 2us at its best.
* So requests to sleep for less then 5us is a waste of CPU time with
* a risk of significant log latency increase due to oversleep.
*/
static uint64_t zil_min_commit_timeout = 5000;
/*
* See zil.h for more information about these fields.
*/
static zil_kstat_values_t zil_stats = {
{ "zil_commit_count", KSTAT_DATA_UINT64 },
{ "zil_commit_writer_count", KSTAT_DATA_UINT64 },
{ "zil_itx_count", KSTAT_DATA_UINT64 },
{ "zil_itx_indirect_count", KSTAT_DATA_UINT64 },
{ "zil_itx_indirect_bytes", KSTAT_DATA_UINT64 },
{ "zil_itx_copied_count", KSTAT_DATA_UINT64 },
{ "zil_itx_copied_bytes", KSTAT_DATA_UINT64 },
{ "zil_itx_needcopy_count", KSTAT_DATA_UINT64 },
{ "zil_itx_needcopy_bytes", KSTAT_DATA_UINT64 },
{ "zil_itx_metaslab_normal_count", KSTAT_DATA_UINT64 },
{ "zil_itx_metaslab_normal_bytes", KSTAT_DATA_UINT64 },
{ "zil_itx_metaslab_normal_write", KSTAT_DATA_UINT64 },
{ "zil_itx_metaslab_normal_alloc", KSTAT_DATA_UINT64 },
{ "zil_itx_metaslab_slog_count", KSTAT_DATA_UINT64 },
{ "zil_itx_metaslab_slog_bytes", KSTAT_DATA_UINT64 },
{ "zil_itx_metaslab_slog_write", KSTAT_DATA_UINT64 },
{ "zil_itx_metaslab_slog_alloc", KSTAT_DATA_UINT64 },
};
static zil_sums_t zil_sums_global;
static kstat_t *zil_kstats_global;
/*
* Disable intent logging replay. This global ZIL switch affects all pools.
*/
int zil_replay_disable = 0;
/*
* Disable the DKIOCFLUSHWRITECACHE commands that are normally sent to
* the disk(s) by the ZIL after an LWB write has completed. Setting this
* will cause ZIL corruption on power loss if a volatile out-of-order
* write cache is enabled.
*/
static int zil_nocacheflush = 0;
/*
* Limit SLOG write size per commit executed with synchronous priority.
* Any writes above that will be executed with lower (asynchronous) priority
* to limit potential SLOG device abuse by single active ZIL writer.
*/
static uint64_t zil_slog_bulk = 64 * 1024 * 1024;
static kmem_cache_t *zil_lwb_cache;
static kmem_cache_t *zil_zcw_cache;
static void zil_lwb_commit(zilog_t *zilog, lwb_t *lwb, itx_t *itx);
static itx_t *zil_itx_clone(itx_t *oitx);
static int
zil_bp_compare(const void *x1, const void *x2)
{
const dva_t *dva1 = &((zil_bp_node_t *)x1)->zn_dva;
const dva_t *dva2 = &((zil_bp_node_t *)x2)->zn_dva;
int cmp = TREE_CMP(DVA_GET_VDEV(dva1), DVA_GET_VDEV(dva2));
if (likely(cmp))
return (cmp);
return (TREE_CMP(DVA_GET_OFFSET(dva1), DVA_GET_OFFSET(dva2)));
}
static void
zil_bp_tree_init(zilog_t *zilog)
{
avl_create(&zilog->zl_bp_tree, zil_bp_compare,
sizeof (zil_bp_node_t), offsetof(zil_bp_node_t, zn_node));
}
static void
zil_bp_tree_fini(zilog_t *zilog)
{
avl_tree_t *t = &zilog->zl_bp_tree;
zil_bp_node_t *zn;
void *cookie = NULL;
while ((zn = avl_destroy_nodes(t, &cookie)) != NULL)
kmem_free(zn, sizeof (zil_bp_node_t));
avl_destroy(t);
}
int
zil_bp_tree_add(zilog_t *zilog, const blkptr_t *bp)
{
avl_tree_t *t = &zilog->zl_bp_tree;
const dva_t *dva;
zil_bp_node_t *zn;
avl_index_t where;
if (BP_IS_EMBEDDED(bp))
return (0);
dva = BP_IDENTITY(bp);
if (avl_find(t, dva, &where) != NULL)
return (SET_ERROR(EEXIST));
zn = kmem_alloc(sizeof (zil_bp_node_t), KM_SLEEP);
zn->zn_dva = *dva;
avl_insert(t, zn, where);
return (0);
}
static zil_header_t *
zil_header_in_syncing_context(zilog_t *zilog)
{
return ((zil_header_t *)zilog->zl_header);
}
static void
zil_init_log_chain(zilog_t *zilog, blkptr_t *bp)
{
zio_cksum_t *zc = &bp->blk_cksum;
(void) random_get_pseudo_bytes((void *)&zc->zc_word[ZIL_ZC_GUID_0],
sizeof (zc->zc_word[ZIL_ZC_GUID_0]));
(void) random_get_pseudo_bytes((void *)&zc->zc_word[ZIL_ZC_GUID_1],
sizeof (zc->zc_word[ZIL_ZC_GUID_1]));
zc->zc_word[ZIL_ZC_OBJSET] = dmu_objset_id(zilog->zl_os);
zc->zc_word[ZIL_ZC_SEQ] = 1ULL;
}
static int
zil_kstats_global_update(kstat_t *ksp, int rw)
{
zil_kstat_values_t *zs = ksp->ks_data;
ASSERT3P(&zil_stats, ==, zs);
if (rw == KSTAT_WRITE) {
return (SET_ERROR(EACCES));
}
zil_kstat_values_update(zs, &zil_sums_global);
return (0);
}
/*
* Read a log block and make sure it's valid.
*/
static int
zil_read_log_block(zilog_t *zilog, boolean_t decrypt, const blkptr_t *bp,
blkptr_t *nbp, char **begin, char **end, arc_buf_t **abuf)
{
zio_flag_t zio_flags = ZIO_FLAG_CANFAIL;
arc_flags_t aflags = ARC_FLAG_WAIT;
zbookmark_phys_t zb;
int error;
if (zilog->zl_header->zh_claim_txg == 0)
zio_flags |= ZIO_FLAG_SPECULATIVE | ZIO_FLAG_SCRUB;
if (!(zilog->zl_header->zh_flags & ZIL_CLAIM_LR_SEQ_VALID))
zio_flags |= ZIO_FLAG_SPECULATIVE;
if (!decrypt)
zio_flags |= ZIO_FLAG_RAW;
SET_BOOKMARK(&zb, bp->blk_cksum.zc_word[ZIL_ZC_OBJSET],
ZB_ZIL_OBJECT, ZB_ZIL_LEVEL, bp->blk_cksum.zc_word[ZIL_ZC_SEQ]);
error = arc_read(NULL, zilog->zl_spa, bp, arc_getbuf_func,
abuf, ZIO_PRIORITY_SYNC_READ, zio_flags, &aflags, &zb);
if (error == 0) {
zio_cksum_t cksum = bp->blk_cksum;
/*
* Validate the checksummed log block.
*
* Sequence numbers should be... sequential. The checksum
* verifier for the next block should be bp's checksum plus 1.
*
* Also check the log chain linkage and size used.
*/
cksum.zc_word[ZIL_ZC_SEQ]++;
uint64_t size = BP_GET_LSIZE(bp);
if (BP_GET_CHECKSUM(bp) == ZIO_CHECKSUM_ZILOG2) {
zil_chain_t *zilc = (*abuf)->b_data;
char *lr = (char *)(zilc + 1);
if (memcmp(&cksum, &zilc->zc_next_blk.blk_cksum,
sizeof (cksum)) ||
zilc->zc_nused < sizeof (*zilc) ||
zilc->zc_nused > size) {
error = SET_ERROR(ECKSUM);
} else {
*begin = lr;
*end = lr + zilc->zc_nused - sizeof (*zilc);
*nbp = zilc->zc_next_blk;
}
} else {
char *lr = (*abuf)->b_data;
zil_chain_t *zilc = (zil_chain_t *)(lr + size) - 1;
if (memcmp(&cksum, &zilc->zc_next_blk.blk_cksum,
sizeof (cksum)) ||
(zilc->zc_nused > (size - sizeof (*zilc)))) {
error = SET_ERROR(ECKSUM);
} else {
*begin = lr;
*end = lr + zilc->zc_nused;
*nbp = zilc->zc_next_blk;
}
}
}
return (error);
}
/*
* Read a TX_WRITE log data block.
*/
static int
zil_read_log_data(zilog_t *zilog, const lr_write_t *lr, void *wbuf)
{
zio_flag_t zio_flags = ZIO_FLAG_CANFAIL;
const blkptr_t *bp = &lr->lr_blkptr;
arc_flags_t aflags = ARC_FLAG_WAIT;
arc_buf_t *abuf = NULL;
zbookmark_phys_t zb;
int error;
if (BP_IS_HOLE(bp)) {
if (wbuf != NULL)
memset(wbuf, 0, MAX(BP_GET_LSIZE(bp), lr->lr_length));
return (0);
}
if (zilog->zl_header->zh_claim_txg == 0)
zio_flags |= ZIO_FLAG_SPECULATIVE | ZIO_FLAG_SCRUB;
/*
* If we are not using the resulting data, we are just checking that
* it hasn't been corrupted so we don't need to waste CPU time
* decompressing and decrypting it.
*/
if (wbuf == NULL)
zio_flags |= ZIO_FLAG_RAW;
ASSERT3U(BP_GET_LSIZE(bp), !=, 0);
SET_BOOKMARK(&zb, dmu_objset_id(zilog->zl_os), lr->lr_foid,
ZB_ZIL_LEVEL, lr->lr_offset / BP_GET_LSIZE(bp));
error = arc_read(NULL, zilog->zl_spa, bp, arc_getbuf_func, &abuf,
ZIO_PRIORITY_SYNC_READ, zio_flags, &aflags, &zb);
if (error == 0) {
if (wbuf != NULL)
memcpy(wbuf, abuf->b_data, arc_buf_size(abuf));
arc_buf_destroy(abuf, &abuf);
}
return (error);
}
void
zil_sums_init(zil_sums_t *zs)
{
wmsum_init(&zs->zil_commit_count, 0);
wmsum_init(&zs->zil_commit_writer_count, 0);
wmsum_init(&zs->zil_itx_count, 0);
wmsum_init(&zs->zil_itx_indirect_count, 0);
wmsum_init(&zs->zil_itx_indirect_bytes, 0);
wmsum_init(&zs->zil_itx_copied_count, 0);
wmsum_init(&zs->zil_itx_copied_bytes, 0);
wmsum_init(&zs->zil_itx_needcopy_count, 0);
wmsum_init(&zs->zil_itx_needcopy_bytes, 0);
wmsum_init(&zs->zil_itx_metaslab_normal_count, 0);
wmsum_init(&zs->zil_itx_metaslab_normal_bytes, 0);
wmsum_init(&zs->zil_itx_metaslab_normal_write, 0);
wmsum_init(&zs->zil_itx_metaslab_normal_alloc, 0);
wmsum_init(&zs->zil_itx_metaslab_slog_count, 0);
wmsum_init(&zs->zil_itx_metaslab_slog_bytes, 0);
wmsum_init(&zs->zil_itx_metaslab_slog_write, 0);
wmsum_init(&zs->zil_itx_metaslab_slog_alloc, 0);
}
void
zil_sums_fini(zil_sums_t *zs)
{
wmsum_fini(&zs->zil_commit_count);
wmsum_fini(&zs->zil_commit_writer_count);
wmsum_fini(&zs->zil_itx_count);
wmsum_fini(&zs->zil_itx_indirect_count);
wmsum_fini(&zs->zil_itx_indirect_bytes);
wmsum_fini(&zs->zil_itx_copied_count);
wmsum_fini(&zs->zil_itx_copied_bytes);
wmsum_fini(&zs->zil_itx_needcopy_count);
wmsum_fini(&zs->zil_itx_needcopy_bytes);
wmsum_fini(&zs->zil_itx_metaslab_normal_count);
wmsum_fini(&zs->zil_itx_metaslab_normal_bytes);
wmsum_fini(&zs->zil_itx_metaslab_normal_write);
wmsum_fini(&zs->zil_itx_metaslab_normal_alloc);
wmsum_fini(&zs->zil_itx_metaslab_slog_count);
wmsum_fini(&zs->zil_itx_metaslab_slog_bytes);
wmsum_fini(&zs->zil_itx_metaslab_slog_write);
wmsum_fini(&zs->zil_itx_metaslab_slog_alloc);
}
void
zil_kstat_values_update(zil_kstat_values_t *zs, zil_sums_t *zil_sums)
{
zs->zil_commit_count.value.ui64 =
wmsum_value(&zil_sums->zil_commit_count);
zs->zil_commit_writer_count.value.ui64 =
wmsum_value(&zil_sums->zil_commit_writer_count);
zs->zil_itx_count.value.ui64 =
wmsum_value(&zil_sums->zil_itx_count);
zs->zil_itx_indirect_count.value.ui64 =
wmsum_value(&zil_sums->zil_itx_indirect_count);
zs->zil_itx_indirect_bytes.value.ui64 =
wmsum_value(&zil_sums->zil_itx_indirect_bytes);
zs->zil_itx_copied_count.value.ui64 =
wmsum_value(&zil_sums->zil_itx_copied_count);
zs->zil_itx_copied_bytes.value.ui64 =
wmsum_value(&zil_sums->zil_itx_copied_bytes);
zs->zil_itx_needcopy_count.value.ui64 =
wmsum_value(&zil_sums->zil_itx_needcopy_count);
zs->zil_itx_needcopy_bytes.value.ui64 =
wmsum_value(&zil_sums->zil_itx_needcopy_bytes);
zs->zil_itx_metaslab_normal_count.value.ui64 =
wmsum_value(&zil_sums->zil_itx_metaslab_normal_count);
zs->zil_itx_metaslab_normal_bytes.value.ui64 =
wmsum_value(&zil_sums->zil_itx_metaslab_normal_bytes);
zs->zil_itx_metaslab_normal_write.value.ui64 =
wmsum_value(&zil_sums->zil_itx_metaslab_normal_write);
zs->zil_itx_metaslab_normal_alloc.value.ui64 =
wmsum_value(&zil_sums->zil_itx_metaslab_normal_alloc);
zs->zil_itx_metaslab_slog_count.value.ui64 =
wmsum_value(&zil_sums->zil_itx_metaslab_slog_count);
zs->zil_itx_metaslab_slog_bytes.value.ui64 =
wmsum_value(&zil_sums->zil_itx_metaslab_slog_bytes);
zs->zil_itx_metaslab_slog_write.value.ui64 =
wmsum_value(&zil_sums->zil_itx_metaslab_slog_write);
zs->zil_itx_metaslab_slog_alloc.value.ui64 =
wmsum_value(&zil_sums->zil_itx_metaslab_slog_alloc);
}
/*
* Parse the intent log, and call parse_func for each valid record within.
*/
int
zil_parse(zilog_t *zilog, zil_parse_blk_func_t *parse_blk_func,
zil_parse_lr_func_t *parse_lr_func, void *arg, uint64_t txg,
boolean_t decrypt)
{
const zil_header_t *zh = zilog->zl_header;
boolean_t claimed = !!zh->zh_claim_txg;
uint64_t claim_blk_seq = claimed ? zh->zh_claim_blk_seq : UINT64_MAX;
uint64_t claim_lr_seq = claimed ? zh->zh_claim_lr_seq : UINT64_MAX;
uint64_t max_blk_seq = 0;
uint64_t max_lr_seq = 0;
uint64_t blk_count = 0;
uint64_t lr_count = 0;
blkptr_t blk, next_blk = {{{{0}}}};
int error = 0;
/*
* Old logs didn't record the maximum zh_claim_lr_seq.
*/
if (!(zh->zh_flags & ZIL_CLAIM_LR_SEQ_VALID))
claim_lr_seq = UINT64_MAX;
/*
* Starting at the block pointed to by zh_log we read the log chain.
* For each block in the chain we strongly check that block to
* ensure its validity. We stop when an invalid block is found.
* For each block pointer in the chain we call parse_blk_func().
* For each record in each valid block we call parse_lr_func().
* If the log has been claimed, stop if we encounter a sequence
* number greater than the highest claimed sequence number.
*/
zil_bp_tree_init(zilog);
for (blk = zh->zh_log; !BP_IS_HOLE(&blk); blk = next_blk) {
uint64_t blk_seq = blk.blk_cksum.zc_word[ZIL_ZC_SEQ];
int reclen;
char *lrp, *end;
arc_buf_t *abuf = NULL;
if (blk_seq > claim_blk_seq)
break;
error = parse_blk_func(zilog, &blk, arg, txg);
if (error != 0)
break;
ASSERT3U(max_blk_seq, <, blk_seq);
max_blk_seq = blk_seq;
blk_count++;
if (max_lr_seq == claim_lr_seq && max_blk_seq == claim_blk_seq)
break;
error = zil_read_log_block(zilog, decrypt, &blk, &next_blk,
&lrp, &end, &abuf);
if (error != 0) {
if (abuf)
arc_buf_destroy(abuf, &abuf);
if (claimed) {
char name[ZFS_MAX_DATASET_NAME_LEN];
dmu_objset_name(zilog->zl_os, name);
cmn_err(CE_WARN, "ZFS read log block error %d, "
"dataset %s, seq 0x%llx\n", error, name,
(u_longlong_t)blk_seq);
}
break;
}
for (; lrp < end; lrp += reclen) {
lr_t *lr = (lr_t *)lrp;
reclen = lr->lrc_reclen;
ASSERT3U(reclen, >=, sizeof (lr_t));
ASSERT3U(reclen, <=, end - lrp);
if (lr->lrc_seq > claim_lr_seq) {
arc_buf_destroy(abuf, &abuf);
goto done;
}
error = parse_lr_func(zilog, lr, arg, txg);
if (error != 0) {
arc_buf_destroy(abuf, &abuf);
goto done;
}
ASSERT3U(max_lr_seq, <, lr->lrc_seq);
max_lr_seq = lr->lrc_seq;
lr_count++;
}
arc_buf_destroy(abuf, &abuf);
}
done:
zilog->zl_parse_error = error;
zilog->zl_parse_blk_seq = max_blk_seq;
zilog->zl_parse_lr_seq = max_lr_seq;
zilog->zl_parse_blk_count = blk_count;
zilog->zl_parse_lr_count = lr_count;
zil_bp_tree_fini(zilog);
return (error);
}
static int
zil_clear_log_block(zilog_t *zilog, const blkptr_t *bp, void *tx,
uint64_t first_txg)
{
(void) tx;
ASSERT(!BP_IS_HOLE(bp));
/*
* As we call this function from the context of a rewind to a
* checkpoint, each ZIL block whose txg is later than the txg
* that we rewind to is invalid. Thus, we return -1 so
* zil_parse() doesn't attempt to read it.
*/
if (bp->blk_birth >= first_txg)
return (-1);
if (zil_bp_tree_add(zilog, bp) != 0)
return (0);
zio_free(zilog->zl_spa, first_txg, bp);
return (0);
}
static int
zil_noop_log_record(zilog_t *zilog, const lr_t *lrc, void *tx,
uint64_t first_txg)
{
(void) zilog, (void) lrc, (void) tx, (void) first_txg;
return (0);
}
static int
zil_claim_log_block(zilog_t *zilog, const blkptr_t *bp, void *tx,
uint64_t first_txg)
{
/*
* Claim log block if not already committed and not already claimed.
* If tx == NULL, just verify that the block is claimable.
*/
if (BP_IS_HOLE(bp) || bp->blk_birth < first_txg ||
zil_bp_tree_add(zilog, bp) != 0)
return (0);
return (zio_wait(zio_claim(NULL, zilog->zl_spa,
tx == NULL ? 0 : first_txg, bp, spa_claim_notify, NULL,
ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE | ZIO_FLAG_SCRUB)));
}
static int
zil_claim_write(zilog_t *zilog, const lr_t *lrc, void *tx, uint64_t first_txg)
{
lr_write_t *lr = (lr_write_t *)lrc;
int error;
ASSERT3U(lrc->lrc_reclen, >=, sizeof (*lr));
/*
* If the block is not readable, don't claim it. This can happen
* in normal operation when a log block is written to disk before
* some of the dmu_sync() blocks it points to. In this case, the
* transaction cannot have been committed to anyone (we would have
* waited for all writes to be stable first), so it is semantically
* correct to declare this the end of the log.
*/
if (lr->lr_blkptr.blk_birth >= first_txg) {
error = zil_read_log_data(zilog, lr, NULL);
if (error != 0)
return (error);
}
return (zil_claim_log_block(zilog, &lr->lr_blkptr, tx, first_txg));
}
static int
zil_claim_clone_range(zilog_t *zilog, const lr_t *lrc, void *tx)
{
const lr_clone_range_t *lr = (const lr_clone_range_t *)lrc;
const blkptr_t *bp;
spa_t *spa;
uint_t ii;
ASSERT3U(lrc->lrc_reclen, >=, sizeof (*lr));
ASSERT3U(lrc->lrc_reclen, >=, offsetof(lr_clone_range_t,
lr_bps[lr->lr_nbps]));
if (tx == NULL) {
return (0);
}
/*
* XXX: Do we need to byteswap lr?
*/
spa = zilog->zl_spa;
for (ii = 0; ii < lr->lr_nbps; ii++) {
bp = &lr->lr_bps[ii];
/*
* When data in embedded into BP there is no need to create
* BRT entry as there is no data block. Just copy the BP as
* it contains the data.
*/
if (!BP_IS_HOLE(bp) && !BP_IS_EMBEDDED(bp)) {
brt_pending_add(spa, bp, tx);
}
}
return (0);
}
static int
zil_claim_log_record(zilog_t *zilog, const lr_t *lrc, void *tx,
uint64_t first_txg)
{
switch (lrc->lrc_txtype) {
case TX_WRITE:
return (zil_claim_write(zilog, lrc, tx, first_txg));
case TX_CLONE_RANGE:
return (zil_claim_clone_range(zilog, lrc, tx));
default:
return (0);
}
}
static int
zil_free_log_block(zilog_t *zilog, const blkptr_t *bp, void *tx,
uint64_t claim_txg)
{
(void) claim_txg;
zio_free(zilog->zl_spa, dmu_tx_get_txg(tx), bp);
return (0);
}
static int
zil_free_write(zilog_t *zilog, const lr_t *lrc, void *tx, uint64_t claim_txg)
{
lr_write_t *lr = (lr_write_t *)lrc;
blkptr_t *bp = &lr->lr_blkptr;
ASSERT3U(lrc->lrc_reclen, >=, sizeof (*lr));
/*
* If we previously claimed it, we need to free it.
*/
if (bp->blk_birth >= claim_txg && zil_bp_tree_add(zilog, bp) == 0 &&
!BP_IS_HOLE(bp)) {
zio_free(zilog->zl_spa, dmu_tx_get_txg(tx), bp);
}
return (0);
}
static int
zil_free_clone_range(zilog_t *zilog, const lr_t *lrc, void *tx)
{
const lr_clone_range_t *lr = (const lr_clone_range_t *)lrc;
const blkptr_t *bp;
spa_t *spa;
uint_t ii;
ASSERT3U(lrc->lrc_reclen, >=, sizeof (*lr));
ASSERT3U(lrc->lrc_reclen, >=, offsetof(lr_clone_range_t,
lr_bps[lr->lr_nbps]));
if (tx == NULL) {
return (0);
}
spa = zilog->zl_spa;
for (ii = 0; ii < lr->lr_nbps; ii++) {
bp = &lr->lr_bps[ii];
if (!BP_IS_HOLE(bp)) {
zio_free(spa, dmu_tx_get_txg(tx), bp);
}
}
return (0);
}
static int
zil_free_log_record(zilog_t *zilog, const lr_t *lrc, void *tx,
uint64_t claim_txg)
{
if (claim_txg == 0) {
return (0);
}
switch (lrc->lrc_txtype) {
case TX_WRITE:
return (zil_free_write(zilog, lrc, tx, claim_txg));
case TX_CLONE_RANGE:
return (zil_free_clone_range(zilog, lrc, tx));
default:
return (0);
}
}
static int
zil_lwb_vdev_compare(const void *x1, const void *x2)
{
const uint64_t v1 = ((zil_vdev_node_t *)x1)->zv_vdev;
const uint64_t v2 = ((zil_vdev_node_t *)x2)->zv_vdev;
return (TREE_CMP(v1, v2));
}
/*
* Allocate a new lwb. We may already have a block pointer for it, in which
* case we get size and version from there. Or we may not yet, in which case
* we choose them here and later make the block allocation match.
*/
static lwb_t *
zil_alloc_lwb(zilog_t *zilog, int sz, blkptr_t *bp, boolean_t slog,
uint64_t txg, lwb_state_t state)
{
lwb_t *lwb;
lwb = kmem_cache_alloc(zil_lwb_cache, KM_SLEEP);
lwb->lwb_zilog = zilog;
if (bp) {
lwb->lwb_blk = *bp;
lwb->lwb_slim = (BP_GET_CHECKSUM(bp) == ZIO_CHECKSUM_ZILOG2);
sz = BP_GET_LSIZE(bp);
} else {
BP_ZERO(&lwb->lwb_blk);
lwb->lwb_slim = (spa_version(zilog->zl_spa) >=
SPA_VERSION_SLIM_ZIL);
}
lwb->lwb_slog = slog;
lwb->lwb_error = 0;
if (lwb->lwb_slim) {
lwb->lwb_nmax = sz;
lwb->lwb_nused = lwb->lwb_nfilled = sizeof (zil_chain_t);
} else {
lwb->lwb_nmax = sz - sizeof (zil_chain_t);
lwb->lwb_nused = lwb->lwb_nfilled = 0;
}
lwb->lwb_sz = sz;
lwb->lwb_state = state;
lwb->lwb_buf = zio_buf_alloc(sz);
lwb->lwb_child_zio = NULL;
lwb->lwb_write_zio = NULL;
lwb->lwb_root_zio = NULL;
lwb->lwb_issued_timestamp = 0;
lwb->lwb_issued_txg = 0;
lwb->lwb_alloc_txg = txg;
lwb->lwb_max_txg = 0;
mutex_enter(&zilog->zl_lock);
list_insert_tail(&zilog->zl_lwb_list, lwb);
if (state != LWB_STATE_NEW)
zilog->zl_last_lwb_opened = lwb;
mutex_exit(&zilog->zl_lock);
return (lwb);
}
static void
zil_free_lwb(zilog_t *zilog, lwb_t *lwb)
{
ASSERT(MUTEX_HELD(&zilog->zl_lock));
ASSERT(lwb->lwb_state == LWB_STATE_NEW ||
lwb->lwb_state == LWB_STATE_FLUSH_DONE);
ASSERT3P(lwb->lwb_child_zio, ==, NULL);
ASSERT3P(lwb->lwb_write_zio, ==, NULL);
ASSERT3P(lwb->lwb_root_zio, ==, NULL);
ASSERT3U(lwb->lwb_alloc_txg, <=, spa_syncing_txg(zilog->zl_spa));
ASSERT3U(lwb->lwb_max_txg, <=, spa_syncing_txg(zilog->zl_spa));
VERIFY(list_is_empty(&lwb->lwb_itxs));
VERIFY(list_is_empty(&lwb->lwb_waiters));
ASSERT(avl_is_empty(&lwb->lwb_vdev_tree));
ASSERT(!MUTEX_HELD(&lwb->lwb_vdev_lock));
/*
* Clear the zilog's field to indicate this lwb is no longer
* valid, and prevent use-after-free errors.
*/
if (zilog->zl_last_lwb_opened == lwb)
zilog->zl_last_lwb_opened = NULL;
kmem_cache_free(zil_lwb_cache, lwb);
}
/*
* Called when we create in-memory log transactions so that we know
* to cleanup the itxs at the end of spa_sync().
*/
static void
zilog_dirty(zilog_t *zilog, uint64_t txg)
{
dsl_pool_t *dp = zilog->zl_dmu_pool;
dsl_dataset_t *ds = dmu_objset_ds(zilog->zl_os);
ASSERT(spa_writeable(zilog->zl_spa));
if (ds->ds_is_snapshot)
panic("dirtying snapshot!");
if (txg_list_add(&dp->dp_dirty_zilogs, zilog, txg)) {
/* up the hold count until we can be written out */
dmu_buf_add_ref(ds->ds_dbuf, zilog);
zilog->zl_dirty_max_txg = MAX(txg, zilog->zl_dirty_max_txg);
}
}
/*
* Determine if the zil is dirty in the specified txg. Callers wanting to
* ensure that the dirty state does not change must hold the itxg_lock for
* the specified txg. Holding the lock will ensure that the zil cannot be
* dirtied (zil_itx_assign) or cleaned (zil_clean) while we check its current
* state.
*/
static boolean_t __maybe_unused
zilog_is_dirty_in_txg(zilog_t *zilog, uint64_t txg)
{
dsl_pool_t *dp = zilog->zl_dmu_pool;
if (txg_list_member(&dp->dp_dirty_zilogs, zilog, txg & TXG_MASK))
return (B_TRUE);
return (B_FALSE);
}
/*
* Determine if the zil is dirty. The zil is considered dirty if it has
* any pending itx records that have not been cleaned by zil_clean().
*/
static boolean_t
zilog_is_dirty(zilog_t *zilog)
{
dsl_pool_t *dp = zilog->zl_dmu_pool;
for (int t = 0; t < TXG_SIZE; t++) {
if (txg_list_member(&dp->dp_dirty_zilogs, zilog, t))
return (B_TRUE);
}
return (B_FALSE);
}
/*
* Its called in zil_commit context (zil_process_commit_list()/zil_create()).
* It activates SPA_FEATURE_ZILSAXATTR feature, if its enabled.
* Check dsl_dataset_feature_is_active to avoid txg_wait_synced() on every
* zil_commit.
*/
static void
zil_commit_activate_saxattr_feature(zilog_t *zilog)
{
dsl_dataset_t *ds = dmu_objset_ds(zilog->zl_os);
uint64_t txg = 0;
dmu_tx_t *tx = NULL;
if (spa_feature_is_enabled(zilog->zl_spa, SPA_FEATURE_ZILSAXATTR) &&
dmu_objset_type(zilog->zl_os) != DMU_OST_ZVOL &&
!dsl_dataset_feature_is_active(ds, SPA_FEATURE_ZILSAXATTR)) {
tx = dmu_tx_create(zilog->zl_os);
VERIFY0(dmu_tx_assign(tx, TXG_WAIT));
dsl_dataset_dirty(ds, tx);
txg = dmu_tx_get_txg(tx);
mutex_enter(&ds->ds_lock);
ds->ds_feature_activation[SPA_FEATURE_ZILSAXATTR] =
(void *)B_TRUE;
mutex_exit(&ds->ds_lock);
dmu_tx_commit(tx);
txg_wait_synced(zilog->zl_dmu_pool, txg);
}
}
/*
* Create an on-disk intent log.
*/
static lwb_t *
zil_create(zilog_t *zilog)
{
const zil_header_t *zh = zilog->zl_header;
lwb_t *lwb = NULL;
uint64_t txg = 0;
dmu_tx_t *tx = NULL;
blkptr_t blk;
int error = 0;
boolean_t slog = FALSE;
dsl_dataset_t *ds = dmu_objset_ds(zilog->zl_os);
/*
* Wait for any previous destroy to complete.
*/
txg_wait_synced(zilog->zl_dmu_pool, zilog->zl_destroy_txg);
ASSERT(zh->zh_claim_txg == 0);
ASSERT(zh->zh_replay_seq == 0);
blk = zh->zh_log;
/*
* Allocate an initial log block if:
* - there isn't one already
* - the existing block is the wrong endianness
*/
if (BP_IS_HOLE(&blk) || BP_SHOULD_BYTESWAP(&blk)) {
tx = dmu_tx_create(zilog->zl_os);
VERIFY0(dmu_tx_assign(tx, TXG_WAIT));
dsl_dataset_dirty(dmu_objset_ds(zilog->zl_os), tx);
txg = dmu_tx_get_txg(tx);
if (!BP_IS_HOLE(&blk)) {
zio_free(zilog->zl_spa, txg, &blk);
BP_ZERO(&blk);
}
error = zio_alloc_zil(zilog->zl_spa, zilog->zl_os, txg, &blk,
ZIL_MIN_BLKSZ, &slog);
if (error == 0)
zil_init_log_chain(zilog, &blk);
}
/*
* Allocate a log write block (lwb) for the first log block.
*/
if (error == 0)
lwb = zil_alloc_lwb(zilog, 0, &blk, slog, txg, LWB_STATE_NEW);
/*
* If we just allocated the first log block, commit our transaction
* and wait for zil_sync() to stuff the block pointer into zh_log.
* (zh is part of the MOS, so we cannot modify it in open context.)
*/
if (tx != NULL) {
/*
* If "zilsaxattr" feature is enabled on zpool, then activate
* it now when we're creating the ZIL chain. We can't wait with
* this until we write the first xattr log record because we
* need to wait for the feature activation to sync out.
*/
if (spa_feature_is_enabled(zilog->zl_spa,
SPA_FEATURE_ZILSAXATTR) && dmu_objset_type(zilog->zl_os) !=
DMU_OST_ZVOL) {
mutex_enter(&ds->ds_lock);
ds->ds_feature_activation[SPA_FEATURE_ZILSAXATTR] =
(void *)B_TRUE;
mutex_exit(&ds->ds_lock);
}
dmu_tx_commit(tx);
txg_wait_synced(zilog->zl_dmu_pool, txg);
} else {
/*
* This branch covers the case where we enable the feature on a
* zpool that has existing ZIL headers.
*/
zil_commit_activate_saxattr_feature(zilog);
}
IMPLY(spa_feature_is_enabled(zilog->zl_spa, SPA_FEATURE_ZILSAXATTR) &&
dmu_objset_type(zilog->zl_os) != DMU_OST_ZVOL,
dsl_dataset_feature_is_active(ds, SPA_FEATURE_ZILSAXATTR));
ASSERT(error != 0 || memcmp(&blk, &zh->zh_log, sizeof (blk)) == 0);
IMPLY(error == 0, lwb != NULL);
return (lwb);
}
/*
* In one tx, free all log blocks and clear the log header. If keep_first
* is set, then we're replaying a log with no content. We want to keep the
* first block, however, so that the first synchronous transaction doesn't
* require a txg_wait_synced() in zil_create(). We don't need to
* txg_wait_synced() here either when keep_first is set, because both
* zil_create() and zil_destroy() will wait for any in-progress destroys
* to complete.
* Return B_TRUE if there were any entries to replay.
*/
boolean_t
zil_destroy(zilog_t *zilog, boolean_t keep_first)
{
const zil_header_t *zh = zilog->zl_header;
lwb_t *lwb;
dmu_tx_t *tx;
uint64_t txg;
/*
* Wait for any previous destroy to complete.
*/
txg_wait_synced(zilog->zl_dmu_pool, zilog->zl_destroy_txg);
zilog->zl_old_header = *zh; /* debugging aid */
if (BP_IS_HOLE(&zh->zh_log))
return (B_FALSE);
tx = dmu_tx_create(zilog->zl_os);
VERIFY0(dmu_tx_assign(tx, TXG_WAIT));
dsl_dataset_dirty(dmu_objset_ds(zilog->zl_os), tx);
txg = dmu_tx_get_txg(tx);
mutex_enter(&zilog->zl_lock);
ASSERT3U(zilog->zl_destroy_txg, <, txg);
zilog->zl_destroy_txg = txg;
zilog->zl_keep_first = keep_first;
if (!list_is_empty(&zilog->zl_lwb_list)) {
ASSERT(zh->zh_claim_txg == 0);
VERIFY(!keep_first);
while ((lwb = list_remove_head(&zilog->zl_lwb_list)) != NULL) {
if (lwb->lwb_buf != NULL)
zio_buf_free(lwb->lwb_buf, lwb->lwb_sz);
if (!BP_IS_HOLE(&lwb->lwb_blk))
zio_free(zilog->zl_spa, txg, &lwb->lwb_blk);
zil_free_lwb(zilog, lwb);
}
} else if (!keep_first) {
zil_destroy_sync(zilog, tx);
}
mutex_exit(&zilog->zl_lock);
dmu_tx_commit(tx);
return (B_TRUE);
}
void
zil_destroy_sync(zilog_t *zilog, dmu_tx_t *tx)
{
ASSERT(list_is_empty(&zilog->zl_lwb_list));
(void) zil_parse(zilog, zil_free_log_block,
zil_free_log_record, tx, zilog->zl_header->zh_claim_txg, B_FALSE);
}
int
zil_claim(dsl_pool_t *dp, dsl_dataset_t *ds, void *txarg)
{
dmu_tx_t *tx = txarg;
zilog_t *zilog;
uint64_t first_txg;
zil_header_t *zh;
objset_t *os;
int error;
error = dmu_objset_own_obj(dp, ds->ds_object,
DMU_OST_ANY, B_FALSE, B_FALSE, FTAG, &os);
if (error != 0) {
/*
* EBUSY indicates that the objset is inconsistent, in which
* case it can not have a ZIL.
*/
if (error != EBUSY) {
cmn_err(CE_WARN, "can't open objset for %llu, error %u",
(unsigned long long)ds->ds_object, error);
}
return (0);
}
zilog = dmu_objset_zil(os);
zh = zil_header_in_syncing_context(zilog);
ASSERT3U(tx->tx_txg, ==, spa_first_txg(zilog->zl_spa));
first_txg = spa_min_claim_txg(zilog->zl_spa);
/*
* If the spa_log_state is not set to be cleared, check whether
* the current uberblock is a checkpoint one and if the current
* header has been claimed before moving on.
*
* If the current uberblock is a checkpointed uberblock then
* one of the following scenarios took place:
*
* 1] We are currently rewinding to the checkpoint of the pool.
* 2] We crashed in the middle of a checkpoint rewind but we
* did manage to write the checkpointed uberblock to the
* vdev labels, so when we tried to import the pool again
* the checkpointed uberblock was selected from the import
* procedure.
*
* In both cases we want to zero out all the ZIL blocks, except
* the ones that have been claimed at the time of the checkpoint
* (their zh_claim_txg != 0). The reason is that these blocks
* may be corrupted since we may have reused their locations on
* disk after we took the checkpoint.
*
* We could try to set spa_log_state to SPA_LOG_CLEAR earlier
* when we first figure out whether the current uberblock is
* checkpointed or not. Unfortunately, that would discard all
* the logs, including the ones that are claimed, and we would
* leak space.
*/
if (spa_get_log_state(zilog->zl_spa) == SPA_LOG_CLEAR ||
(zilog->zl_spa->spa_uberblock.ub_checkpoint_txg != 0 &&
zh->zh_claim_txg == 0)) {
if (!BP_IS_HOLE(&zh->zh_log)) {
(void) zil_parse(zilog, zil_clear_log_block,
zil_noop_log_record, tx, first_txg, B_FALSE);
}
BP_ZERO(&zh->zh_log);
if (os->os_encrypted)
os->os_next_write_raw[tx->tx_txg & TXG_MASK] = B_TRUE;
dsl_dataset_dirty(dmu_objset_ds(os), tx);
dmu_objset_disown(os, B_FALSE, FTAG);
return (0);
}
/*
* If we are not rewinding and opening the pool normally, then
* the min_claim_txg should be equal to the first txg of the pool.
*/
ASSERT3U(first_txg, ==, spa_first_txg(zilog->zl_spa));
/*
* Claim all log blocks if we haven't already done so, and remember
* the highest claimed sequence number. This ensures that if we can
* read only part of the log now (e.g. due to a missing device),
* but we can read the entire log later, we will not try to replay
* or destroy beyond the last block we successfully claimed.
*/
ASSERT3U(zh->zh_claim_txg, <=, first_txg);
if (zh->zh_claim_txg == 0 && !BP_IS_HOLE(&zh->zh_log)) {
(void) zil_parse(zilog, zil_claim_log_block,
zil_claim_log_record, tx, first_txg, B_FALSE);
zh->zh_claim_txg = first_txg;
zh->zh_claim_blk_seq = zilog->zl_parse_blk_seq;
zh->zh_claim_lr_seq = zilog->zl_parse_lr_seq;
if (zilog->zl_parse_lr_count || zilog->zl_parse_blk_count > 1)
zh->zh_flags |= ZIL_REPLAY_NEEDED;
zh->zh_flags |= ZIL_CLAIM_LR_SEQ_VALID;
if (os->os_encrypted)
os->os_next_write_raw[tx->tx_txg & TXG_MASK] = B_TRUE;
dsl_dataset_dirty(dmu_objset_ds(os), tx);
}
ASSERT3U(first_txg, ==, (spa_last_synced_txg(zilog->zl_spa) + 1));
dmu_objset_disown(os, B_FALSE, FTAG);
return (0);
}
/*
* Check the log by walking the log chain.
* Checksum errors are ok as they indicate the end of the chain.
* Any other error (no device or read failure) returns an error.
*/
int
zil_check_log_chain(dsl_pool_t *dp, dsl_dataset_t *ds, void *tx)
{
(void) dp;
zilog_t *zilog;
objset_t *os;
blkptr_t *bp;
int error;
ASSERT(tx == NULL);
error = dmu_objset_from_ds(ds, &os);
if (error != 0) {
cmn_err(CE_WARN, "can't open objset %llu, error %d",
(unsigned long long)ds->ds_object, error);
return (0);
}
zilog = dmu_objset_zil(os);
bp = (blkptr_t *)&zilog->zl_header->zh_log;
if (!BP_IS_HOLE(bp)) {
vdev_t *vd;
boolean_t valid = B_TRUE;
/*
* Check the first block and determine if it's on a log device
* which may have been removed or faulted prior to loading this
* pool. If so, there's no point in checking the rest of the
* log as its content should have already been synced to the
* pool.
*/
spa_config_enter(os->os_spa, SCL_STATE, FTAG, RW_READER);
vd = vdev_lookup_top(os->os_spa, DVA_GET_VDEV(&bp->blk_dva[0]));
if (vd->vdev_islog && vdev_is_dead(vd))
valid = vdev_log_state_valid(vd);
spa_config_exit(os->os_spa, SCL_STATE, FTAG);
if (!valid)
return (0);
/*
* Check whether the current uberblock is checkpointed (e.g.
* we are rewinding) and whether the current header has been
* claimed or not. If it hasn't then skip verifying it. We
* do this because its ZIL blocks may be part of the pool's
* state before the rewind, which is no longer valid.
*/
zil_header_t *zh = zil_header_in_syncing_context(zilog);
if (zilog->zl_spa->spa_uberblock.ub_checkpoint_txg != 0 &&
zh->zh_claim_txg == 0)
return (0);
}
/*
* Because tx == NULL, zil_claim_log_block() will not actually claim
* any blocks, but just determine whether it is possible to do so.
* In addition to checking the log chain, zil_claim_log_block()
* will invoke zio_claim() with a done func of spa_claim_notify(),
* which will update spa_max_claim_txg. See spa_load() for details.
*/
error = zil_parse(zilog, zil_claim_log_block, zil_claim_log_record, tx,
zilog->zl_header->zh_claim_txg ? -1ULL :
spa_min_claim_txg(os->os_spa), B_FALSE);
return ((error == ECKSUM || error == ENOENT) ? 0 : error);
}
/*
* When an itx is "skipped", this function is used to properly mark the
* waiter as "done, and signal any thread(s) waiting on it. An itx can
* be skipped (and not committed to an lwb) for a variety of reasons,
* one of them being that the itx was committed via spa_sync(), prior to
* it being committed to an lwb; this can happen if a thread calling
* zil_commit() is racing with spa_sync().
*/
static void
zil_commit_waiter_skip(zil_commit_waiter_t *zcw)
{
mutex_enter(&zcw->zcw_lock);
ASSERT3B(zcw->zcw_done, ==, B_FALSE);
zcw->zcw_done = B_TRUE;
cv_broadcast(&zcw->zcw_cv);
mutex_exit(&zcw->zcw_lock);
}
/*
* This function is used when the given waiter is to be linked into an
* lwb's "lwb_waiter" list; i.e. when the itx is committed to the lwb.
* At this point, the waiter will no longer be referenced by the itx,
* and instead, will be referenced by the lwb.
*/
static void
zil_commit_waiter_link_lwb(zil_commit_waiter_t *zcw, lwb_t *lwb)
{
/*
* The lwb_waiters field of the lwb is protected by the zilog's
* zl_issuer_lock while the lwb is open and zl_lock otherwise.
* zl_issuer_lock also protects leaving the open state.
* zcw_lwb setting is protected by zl_issuer_lock and state !=
* flush_done, which transition is protected by zl_lock.
*/
ASSERT(MUTEX_HELD(&lwb->lwb_zilog->zl_issuer_lock));
IMPLY(lwb->lwb_state != LWB_STATE_OPENED,
MUTEX_HELD(&lwb->lwb_zilog->zl_lock));
ASSERT3S(lwb->lwb_state, !=, LWB_STATE_NEW);
ASSERT3S(lwb->lwb_state, !=, LWB_STATE_FLUSH_DONE);
ASSERT(!list_link_active(&zcw->zcw_node));
list_insert_tail(&lwb->lwb_waiters, zcw);
ASSERT3P(zcw->zcw_lwb, ==, NULL);
zcw->zcw_lwb = lwb;
}
/*
* This function is used when zio_alloc_zil() fails to allocate a ZIL
* block, and the given waiter must be linked to the "nolwb waiters"
* list inside of zil_process_commit_list().
*/
static void
zil_commit_waiter_link_nolwb(zil_commit_waiter_t *zcw, list_t *nolwb)
{
ASSERT(!list_link_active(&zcw->zcw_node));
list_insert_tail(nolwb, zcw);
ASSERT3P(zcw->zcw_lwb, ==, NULL);
}
void
zil_lwb_add_block(lwb_t *lwb, const blkptr_t *bp)
{
avl_tree_t *t = &lwb->lwb_vdev_tree;
avl_index_t where;
zil_vdev_node_t *zv, zvsearch;
int ndvas = BP_GET_NDVAS(bp);
int i;
ASSERT3S(lwb->lwb_state, !=, LWB_STATE_WRITE_DONE);
ASSERT3S(lwb->lwb_state, !=, LWB_STATE_FLUSH_DONE);
if (zil_nocacheflush)
return;
mutex_enter(&lwb->lwb_vdev_lock);
for (i = 0; i < ndvas; i++) {
zvsearch.zv_vdev = DVA_GET_VDEV(&bp->blk_dva[i]);
if (avl_find(t, &zvsearch, &where) == NULL) {
zv = kmem_alloc(sizeof (*zv), KM_SLEEP);
zv->zv_vdev = zvsearch.zv_vdev;
avl_insert(t, zv, where);
}
}
mutex_exit(&lwb->lwb_vdev_lock);
}
static void
zil_lwb_flush_defer(lwb_t *lwb, lwb_t *nlwb)
{
avl_tree_t *src = &lwb->lwb_vdev_tree;
avl_tree_t *dst = &nlwb->lwb_vdev_tree;
void *cookie = NULL;
zil_vdev_node_t *zv;
ASSERT3S(lwb->lwb_state, ==, LWB_STATE_WRITE_DONE);
ASSERT3S(nlwb->lwb_state, !=, LWB_STATE_WRITE_DONE);
ASSERT3S(nlwb->lwb_state, !=, LWB_STATE_FLUSH_DONE);
/*
* While 'lwb' is at a point in its lifetime where lwb_vdev_tree does
* not need the protection of lwb_vdev_lock (it will only be modified
* while holding zilog->zl_lock) as its writes and those of its
* children have all completed. The younger 'nlwb' may be waiting on
* future writes to additional vdevs.
*/
mutex_enter(&nlwb->lwb_vdev_lock);
/*
* Tear down the 'lwb' vdev tree, ensuring that entries which do not
* exist in 'nlwb' are moved to it, freeing any would-be duplicates.
*/
while ((zv = avl_destroy_nodes(src, &cookie)) != NULL) {
avl_index_t where;
if (avl_find(dst, zv, &where) == NULL) {
avl_insert(dst, zv, where);
} else {
kmem_free(zv, sizeof (*zv));
}
}
mutex_exit(&nlwb->lwb_vdev_lock);
}
void
zil_lwb_add_txg(lwb_t *lwb, uint64_t txg)
{
lwb->lwb_max_txg = MAX(lwb->lwb_max_txg, txg);
}
/*
* This function is a called after all vdevs associated with a given lwb
* write have completed their DKIOCFLUSHWRITECACHE command; or as soon
* as the lwb write completes, if "zil_nocacheflush" is set. Further,
* all "previous" lwb's will have completed before this function is
* called; i.e. this function is called for all previous lwbs before
* it's called for "this" lwb (enforced via zio the dependencies
* configured in zil_lwb_set_zio_dependency()).
*
* The intention is for this function to be called as soon as the
* contents of an lwb are considered "stable" on disk, and will survive
* any sudden loss of power. At this point, any threads waiting for the
* lwb to reach this state are signalled, and the "waiter" structures
* are marked "done".
*/
static void
zil_lwb_flush_vdevs_done(zio_t *zio)
{
lwb_t *lwb = zio->io_private;
zilog_t *zilog = lwb->lwb_zilog;
zil_commit_waiter_t *zcw;
itx_t *itx;
spa_config_exit(zilog->zl_spa, SCL_STATE, lwb);
hrtime_t t = gethrtime() - lwb->lwb_issued_timestamp;
mutex_enter(&zilog->zl_lock);
zilog->zl_last_lwb_latency = (zilog->zl_last_lwb_latency * 7 + t) / 8;
lwb->lwb_root_zio = NULL;
ASSERT3S(lwb->lwb_state, ==, LWB_STATE_WRITE_DONE);
lwb->lwb_state = LWB_STATE_FLUSH_DONE;
if (zilog->zl_last_lwb_opened == lwb) {
/*
* Remember the highest committed log sequence number
* for ztest. We only update this value when all the log
* writes succeeded, because ztest wants to ASSERT that
* it got the whole log chain.
*/
zilog->zl_commit_lr_seq = zilog->zl_lr_seq;
}
while ((itx = list_remove_head(&lwb->lwb_itxs)) != NULL)
zil_itx_destroy(itx);
while ((zcw = list_remove_head(&lwb->lwb_waiters)) != NULL) {
mutex_enter(&zcw->zcw_lock);
ASSERT3P(zcw->zcw_lwb, ==, lwb);
zcw->zcw_lwb = NULL;
/*
* We expect any ZIO errors from child ZIOs to have been
* propagated "up" to this specific LWB's root ZIO, in
* order for this error handling to work correctly. This
* includes ZIO errors from either this LWB's write or
* flush, as well as any errors from other dependent LWBs
* (e.g. a root LWB ZIO that might be a child of this LWB).
*
* With that said, it's important to note that LWB flush
* errors are not propagated up to the LWB root ZIO.
* This is incorrect behavior, and results in VDEV flush
* errors not being handled correctly here. See the
* comment above the call to "zio_flush" for details.
*/
zcw->zcw_zio_error = zio->io_error;
ASSERT3B(zcw->zcw_done, ==, B_FALSE);
zcw->zcw_done = B_TRUE;
cv_broadcast(&zcw->zcw_cv);
mutex_exit(&zcw->zcw_lock);
}
uint64_t txg = lwb->lwb_issued_txg;
/* Once we drop the lock, lwb may be freed by zil_sync(). */
mutex_exit(&zilog->zl_lock);
mutex_enter(&zilog->zl_lwb_io_lock);
ASSERT3U(zilog->zl_lwb_inflight[txg & TXG_MASK], >, 0);
zilog->zl_lwb_inflight[txg & TXG_MASK]--;
if (zilog->zl_lwb_inflight[txg & TXG_MASK] == 0)
cv_broadcast(&zilog->zl_lwb_io_cv);
mutex_exit(&zilog->zl_lwb_io_lock);
}
/*
* Wait for the completion of all issued write/flush of that txg provided.
* It guarantees zil_lwb_flush_vdevs_done() is called and returned.
*/
static void
zil_lwb_flush_wait_all(zilog_t *zilog, uint64_t txg)
{
ASSERT3U(txg, ==, spa_syncing_txg(zilog->zl_spa));
mutex_enter(&zilog->zl_lwb_io_lock);
while (zilog->zl_lwb_inflight[txg & TXG_MASK] > 0)
cv_wait(&zilog->zl_lwb_io_cv, &zilog->zl_lwb_io_lock);
mutex_exit(&zilog->zl_lwb_io_lock);
#ifdef ZFS_DEBUG
mutex_enter(&zilog->zl_lock);
mutex_enter(&zilog->zl_lwb_io_lock);
lwb_t *lwb = list_head(&zilog->zl_lwb_list);
while (lwb != NULL) {
if (lwb->lwb_issued_txg <= txg) {
ASSERT(lwb->lwb_state != LWB_STATE_ISSUED);
ASSERT(lwb->lwb_state != LWB_STATE_WRITE_DONE);
IMPLY(lwb->lwb_issued_txg > 0,
lwb->lwb_state == LWB_STATE_FLUSH_DONE);
}
IMPLY(lwb->lwb_state == LWB_STATE_WRITE_DONE ||
lwb->lwb_state == LWB_STATE_FLUSH_DONE,
lwb->lwb_buf == NULL);
lwb = list_next(&zilog->zl_lwb_list, lwb);
}
mutex_exit(&zilog->zl_lwb_io_lock);
mutex_exit(&zilog->zl_lock);
#endif
}
/*
* This is called when an lwb's write zio completes. The callback's
* purpose is to issue the DKIOCFLUSHWRITECACHE commands for the vdevs
* in the lwb's lwb_vdev_tree. The tree will contain the vdevs involved
* in writing out this specific lwb's data, and in the case that cache
* flushes have been deferred, vdevs involved in writing the data for
* previous lwbs. The writes corresponding to all the vdevs in the
* lwb_vdev_tree will have completed by the time this is called, due to
* the zio dependencies configured in zil_lwb_set_zio_dependency(),
* which takes deferred flushes into account. The lwb will be "done"
* once zil_lwb_flush_vdevs_done() is called, which occurs in the zio
* completion callback for the lwb's root zio.
*/
static void
zil_lwb_write_done(zio_t *zio)
{
lwb_t *lwb = zio->io_private;
spa_t *spa = zio->io_spa;
zilog_t *zilog = lwb->lwb_zilog;
avl_tree_t *t = &lwb->lwb_vdev_tree;
void *cookie = NULL;
zil_vdev_node_t *zv;
lwb_t *nlwb;
ASSERT3S(spa_config_held(spa, SCL_STATE, RW_READER), !=, 0);
abd_free(zio->io_abd);
zio_buf_free(lwb->lwb_buf, lwb->lwb_sz);
lwb->lwb_buf = NULL;
mutex_enter(&zilog->zl_lock);
ASSERT3S(lwb->lwb_state, ==, LWB_STATE_ISSUED);
lwb->lwb_state = LWB_STATE_WRITE_DONE;
lwb->lwb_child_zio = NULL;
lwb->lwb_write_zio = NULL;
/*
* If nlwb is not yet issued, zil_lwb_set_zio_dependency() is not
* called for it yet, and when it will be, it won't be able to make
* its write ZIO a parent this ZIO. In such case we can not defer
* our flushes or below may be a race between the done callbacks.
*/
nlwb = list_next(&zilog->zl_lwb_list, lwb);
if (nlwb && nlwb->lwb_state != LWB_STATE_ISSUED)
nlwb = NULL;
mutex_exit(&zilog->zl_lock);
if (avl_numnodes(t) == 0)
return;
/*
* If there was an IO error, we're not going to call zio_flush()
* on these vdevs, so we simply empty the tree and free the
* nodes. We avoid calling zio_flush() since there isn't any
* good reason for doing so, after the lwb block failed to be
* written out.
*
* Additionally, we don't perform any further error handling at
* this point (e.g. setting "zcw_zio_error" appropriately), as
* we expect that to occur in "zil_lwb_flush_vdevs_done" (thus,
* we expect any error seen here, to have been propagated to
* that function).
*/
if (zio->io_error != 0) {
while ((zv = avl_destroy_nodes(t, &cookie)) != NULL)
kmem_free(zv, sizeof (*zv));
return;
}
/*
* If this lwb does not have any threads waiting for it to
* complete, we want to defer issuing the DKIOCFLUSHWRITECACHE
* command to the vdevs written to by "this" lwb, and instead
* rely on the "next" lwb to handle the DKIOCFLUSHWRITECACHE
* command for those vdevs. Thus, we merge the vdev tree of
* "this" lwb with the vdev tree of the "next" lwb in the list,
* and assume the "next" lwb will handle flushing the vdevs (or
* deferring the flush(s) again).
*
* This is a useful performance optimization, especially for
* workloads with lots of async write activity and few sync
* write and/or fsync activity, as it has the potential to
* coalesce multiple flush commands to a vdev into one.
*/
if (list_is_empty(&lwb->lwb_waiters) && nlwb != NULL) {
zil_lwb_flush_defer(lwb, nlwb);
ASSERT(avl_is_empty(&lwb->lwb_vdev_tree));
return;
}
while ((zv = avl_destroy_nodes(t, &cookie)) != NULL) {
vdev_t *vd = vdev_lookup_top(spa, zv->zv_vdev);
if (vd != NULL && !vd->vdev_nowritecache) {
/*
* The "ZIO_FLAG_DONT_PROPAGATE" is currently
* always used within "zio_flush". This means,
* any errors when flushing the vdev(s), will
* (unfortunately) not be handled correctly,
* since these "zio_flush" errors will not be
* propagated up to "zil_lwb_flush_vdevs_done".
*/
zio_flush(lwb->lwb_root_zio, vd);
}
kmem_free(zv, sizeof (*zv));
}
}
/*
* Build the zio dependency chain, which is used to preserve the ordering of
* lwb completions that is required by the semantics of the ZIL. Each new lwb
* zio becomes a parent of the previous lwb zio, such that the new lwb's zio
* cannot complete until the previous lwb's zio completes.
*
* This is required by the semantics of zil_commit(): the commit waiters
* attached to the lwbs will be woken in the lwb zio's completion callback,
* so this zio dependency graph ensures the waiters are woken in the correct
* order (the same order the lwbs were created).
*/
static void
zil_lwb_set_zio_dependency(zilog_t *zilog, lwb_t *lwb)
{
ASSERT(MUTEX_HELD(&zilog->zl_lock));
lwb_t *prev_lwb = list_prev(&zilog->zl_lwb_list, lwb);
if (prev_lwb == NULL ||
prev_lwb->lwb_state == LWB_STATE_FLUSH_DONE)
return;
/*
* If the previous lwb's write hasn't already completed, we also want
* to order the completion of the lwb write zios (above, we only order
* the completion of the lwb root zios). This is required because of
* how we can defer the DKIOCFLUSHWRITECACHE commands for each lwb.
*
* When the DKIOCFLUSHWRITECACHE commands are deferred, the previous
* lwb will rely on this lwb to flush the vdevs written to by that
* previous lwb. Thus, we need to ensure this lwb doesn't issue the
* flush until after the previous lwb's write completes. We ensure
* this ordering by setting the zio parent/child relationship here.
*
* Without this relationship on the lwb's write zio, it's possible
* for this lwb's write to complete prior to the previous lwb's write
* completing; and thus, the vdevs for the previous lwb would be
* flushed prior to that lwb's data being written to those vdevs (the
* vdevs are flushed in the lwb write zio's completion handler,
* zil_lwb_write_done()).
*/
if (prev_lwb->lwb_state == LWB_STATE_ISSUED) {
ASSERT3P(prev_lwb->lwb_write_zio, !=, NULL);
zio_add_child(lwb->lwb_write_zio, prev_lwb->lwb_write_zio);
} else {
ASSERT3S(prev_lwb->lwb_state, ==, LWB_STATE_WRITE_DONE);
}
ASSERT3P(prev_lwb->lwb_root_zio, !=, NULL);
zio_add_child(lwb->lwb_root_zio, prev_lwb->lwb_root_zio);
}
/*
* This function's purpose is to "open" an lwb such that it is ready to
* accept new itxs being committed to it. This function is idempotent; if
* the passed in lwb has already been opened, it is essentially a no-op.
*/
static void
zil_lwb_write_open(zilog_t *zilog, lwb_t *lwb)
{
ASSERT(MUTEX_HELD(&zilog->zl_issuer_lock));
if (lwb->lwb_state != LWB_STATE_NEW) {
ASSERT3S(lwb->lwb_state, ==, LWB_STATE_OPENED);
return;
}
mutex_enter(&zilog->zl_lock);
lwb->lwb_state = LWB_STATE_OPENED;
zilog->zl_last_lwb_opened = lwb;
mutex_exit(&zilog->zl_lock);
}
/*
* Define a limited set of intent log block sizes.
*
* These must be a multiple of 4KB. Note only the amount used (again
* aligned to 4KB) actually gets written. However, we can't always just
* allocate SPA_OLD_MAXBLOCKSIZE as the slog space could be exhausted.
*/
static const struct {
uint64_t limit;
uint64_t blksz;
} zil_block_buckets[] = {
{ 4096, 4096 }, /* non TX_WRITE */
{ 8192 + 4096, 8192 + 4096 }, /* database */
{ 32768 + 4096, 32768 + 4096 }, /* NFS writes */
{ 65536 + 4096, 65536 + 4096 }, /* 64KB writes */
{ 131072, 131072 }, /* < 128KB writes */
{ 131072 +4096, 65536 + 4096 }, /* 128KB writes */
{ UINT64_MAX, SPA_OLD_MAXBLOCKSIZE}, /* > 128KB writes */
};
/*
* Maximum block size used by the ZIL. This is picked up when the ZIL is
* initialized. Otherwise this should not be used directly; see
* zl_max_block_size instead.
*/
static uint_t zil_maxblocksize = SPA_OLD_MAXBLOCKSIZE;
/*
* Close the log block for being issued and allocate the next one.
* Has to be called under zl_issuer_lock to chain more lwbs.
*/
static lwb_t *
zil_lwb_write_close(zilog_t *zilog, lwb_t *lwb, lwb_state_t state)
{
int i;
ASSERT(MUTEX_HELD(&zilog->zl_issuer_lock));
ASSERT3S(lwb->lwb_state, ==, LWB_STATE_OPENED);
lwb->lwb_state = LWB_STATE_CLOSED;
/*
* If there was an allocation failure then returned NULL will trigger
* zil_commit_writer_stall() at the caller. This is inherently racy,
* since allocation may not have happened yet.
*/
if (lwb->lwb_error != 0)
return (NULL);
/*
* Log blocks are pre-allocated. Here we select the size of the next
* block, based on size used in the last block.
* - first find the smallest bucket that will fit the block from a
* limited set of block sizes. This is because it's faster to write
* blocks allocated from the same metaslab as they are adjacent or
* close.
* - next find the maximum from the new suggested size and an array of
* previous sizes. This lessens a picket fence effect of wrongly
* guessing the size if we have a stream of say 2k, 64k, 2k, 64k
* requests.
*
* Note we only write what is used, but we can't just allocate
* the maximum block size because we can exhaust the available
* pool log space.
*/
uint64_t zil_blksz = zilog->zl_cur_used + sizeof (zil_chain_t);
for (i = 0; zil_blksz > zil_block_buckets[i].limit; i++)
continue;
zil_blksz = MIN(zil_block_buckets[i].blksz, zilog->zl_max_block_size);
zilog->zl_prev_blks[zilog->zl_prev_rotor] = zil_blksz;
for (i = 0; i < ZIL_PREV_BLKS; i++)
zil_blksz = MAX(zil_blksz, zilog->zl_prev_blks[i]);
DTRACE_PROBE3(zil__block__size, zilog_t *, zilog,
uint64_t, zil_blksz,
uint64_t, zilog->zl_prev_blks[zilog->zl_prev_rotor]);
zilog->zl_prev_rotor = (zilog->zl_prev_rotor + 1) & (ZIL_PREV_BLKS - 1);
return (zil_alloc_lwb(zilog, zil_blksz, NULL, 0, 0, state));
}
/*
* Finalize previously closed block and issue the write zio.
*/
static void
zil_lwb_write_issue(zilog_t *zilog, lwb_t *lwb)
{
spa_t *spa = zilog->zl_spa;
zil_chain_t *zilc;
boolean_t slog;
zbookmark_phys_t zb;
zio_priority_t prio;
int error;
ASSERT3S(lwb->lwb_state, ==, LWB_STATE_CLOSED);
/* Actually fill the lwb with the data. */
for (itx_t *itx = list_head(&lwb->lwb_itxs); itx;
itx = list_next(&lwb->lwb_itxs, itx))
zil_lwb_commit(zilog, lwb, itx);
lwb->lwb_nused = lwb->lwb_nfilled;
ASSERT3U(lwb->lwb_nused, <=, lwb->lwb_nmax);
lwb->lwb_root_zio = zio_root(spa, zil_lwb_flush_vdevs_done, lwb,
ZIO_FLAG_CANFAIL);
/*
* The lwb is now ready to be issued, but it can be only if it already
* got its block pointer allocated or the allocation has failed.
* Otherwise leave it as-is, relying on some other thread to issue it
* after allocating its block pointer via calling zil_lwb_write_issue()
* for the previous lwb(s) in the chain.
*/
mutex_enter(&zilog->zl_lock);
lwb->lwb_state = LWB_STATE_READY;
if (BP_IS_HOLE(&lwb->lwb_blk) && lwb->lwb_error == 0) {
mutex_exit(&zilog->zl_lock);
return;
}
mutex_exit(&zilog->zl_lock);
next_lwb:
if (lwb->lwb_slim)
zilc = (zil_chain_t *)lwb->lwb_buf;
else
zilc = (zil_chain_t *)(lwb->lwb_buf + lwb->lwb_nmax);
int wsz = lwb->lwb_sz;
if (lwb->lwb_error == 0) {
abd_t *lwb_abd = abd_get_from_buf(lwb->lwb_buf, lwb->lwb_sz);
if (!lwb->lwb_slog || zilog->zl_cur_used <= zil_slog_bulk)
prio = ZIO_PRIORITY_SYNC_WRITE;
else
prio = ZIO_PRIORITY_ASYNC_WRITE;
SET_BOOKMARK(&zb, lwb->lwb_blk.blk_cksum.zc_word[ZIL_ZC_OBJSET],
ZB_ZIL_OBJECT, ZB_ZIL_LEVEL,
lwb->lwb_blk.blk_cksum.zc_word[ZIL_ZC_SEQ]);
lwb->lwb_write_zio = zio_rewrite(lwb->lwb_root_zio, spa, 0,
&lwb->lwb_blk, lwb_abd, lwb->lwb_sz, zil_lwb_write_done,
lwb, prio, ZIO_FLAG_CANFAIL, &zb);
zil_lwb_add_block(lwb, &lwb->lwb_blk);
if (lwb->lwb_slim) {
/* For Slim ZIL only write what is used. */
wsz = P2ROUNDUP_TYPED(lwb->lwb_nused, ZIL_MIN_BLKSZ,
int);
ASSERT3S(wsz, <=, lwb->lwb_sz);
zio_shrink(lwb->lwb_write_zio, wsz);
wsz = lwb->lwb_write_zio->io_size;
}
memset(lwb->lwb_buf + lwb->lwb_nused, 0, wsz - lwb->lwb_nused);
zilc->zc_pad = 0;
zilc->zc_nused = lwb->lwb_nused;
zilc->zc_eck.zec_cksum = lwb->lwb_blk.blk_cksum;
} else {
/*
* We can't write the lwb if there was an allocation failure,
* so create a null zio instead just to maintain dependencies.
*/
lwb->lwb_write_zio = zio_null(lwb->lwb_root_zio, spa, NULL,
zil_lwb_write_done, lwb, ZIO_FLAG_CANFAIL);
lwb->lwb_write_zio->io_error = lwb->lwb_error;
}
if (lwb->lwb_child_zio)
zio_add_child(lwb->lwb_write_zio, lwb->lwb_child_zio);
/*
* Open transaction to allocate the next block pointer.
*/
dmu_tx_t *tx = dmu_tx_create(zilog->zl_os);
VERIFY0(dmu_tx_assign(tx, TXG_WAIT | TXG_NOTHROTTLE));
dsl_dataset_dirty(dmu_objset_ds(zilog->zl_os), tx);
uint64_t txg = dmu_tx_get_txg(tx);
/*
* Allocate next the block pointer unless we are already in error.
*/
lwb_t *nlwb = list_next(&zilog->zl_lwb_list, lwb);
blkptr_t *bp = &zilc->zc_next_blk;
BP_ZERO(bp);
error = lwb->lwb_error;
if (error == 0) {
error = zio_alloc_zil(spa, zilog->zl_os, txg, bp, nlwb->lwb_sz,
&slog);
}
if (error == 0) {
ASSERT3U(bp->blk_birth, ==, txg);
BP_SET_CHECKSUM(bp, nlwb->lwb_slim ? ZIO_CHECKSUM_ZILOG2 :
ZIO_CHECKSUM_ZILOG);
bp->blk_cksum = lwb->lwb_blk.blk_cksum;
bp->blk_cksum.zc_word[ZIL_ZC_SEQ]++;
}
/*
* Reduce TXG open time by incrementing inflight counter and committing
* the transaciton. zil_sync() will wait for it to return to zero.
*/
mutex_enter(&zilog->zl_lwb_io_lock);
lwb->lwb_issued_txg = txg;
zilog->zl_lwb_inflight[txg & TXG_MASK]++;
zilog->zl_lwb_max_issued_txg = MAX(txg, zilog->zl_lwb_max_issued_txg);
mutex_exit(&zilog->zl_lwb_io_lock);
dmu_tx_commit(tx);
spa_config_enter(spa, SCL_STATE, lwb, RW_READER);
/*
* We've completed all potentially blocking operations. Update the
* nlwb and allow it proceed without possible lock order reversals.
*/
mutex_enter(&zilog->zl_lock);
zil_lwb_set_zio_dependency(zilog, lwb);
lwb->lwb_state = LWB_STATE_ISSUED;
if (nlwb) {
nlwb->lwb_blk = *bp;
nlwb->lwb_error = error;
nlwb->lwb_slog = slog;
nlwb->lwb_alloc_txg = txg;
if (nlwb->lwb_state != LWB_STATE_READY)
nlwb = NULL;
}
mutex_exit(&zilog->zl_lock);
if (lwb->lwb_slog) {
ZIL_STAT_BUMP(zilog, zil_itx_metaslab_slog_count);
ZIL_STAT_INCR(zilog, zil_itx_metaslab_slog_bytes,
lwb->lwb_nused);
ZIL_STAT_INCR(zilog, zil_itx_metaslab_slog_write,
wsz);
ZIL_STAT_INCR(zilog, zil_itx_metaslab_slog_alloc,
BP_GET_LSIZE(&lwb->lwb_blk));
} else {
ZIL_STAT_BUMP(zilog, zil_itx_metaslab_normal_count);
ZIL_STAT_INCR(zilog, zil_itx_metaslab_normal_bytes,
lwb->lwb_nused);
ZIL_STAT_INCR(zilog, zil_itx_metaslab_normal_write,
wsz);
ZIL_STAT_INCR(zilog, zil_itx_metaslab_normal_alloc,
BP_GET_LSIZE(&lwb->lwb_blk));
}
lwb->lwb_issued_timestamp = gethrtime();
if (lwb->lwb_child_zio)
zio_nowait(lwb->lwb_child_zio);
zio_nowait(lwb->lwb_write_zio);
zio_nowait(lwb->lwb_root_zio);
/*
* If nlwb was ready when we gave it the block pointer,
* it is on us to issue it and possibly following ones.
*/
lwb = nlwb;
if (lwb)
goto next_lwb;
}
/*
* Maximum amount of data that can be put into single log block.
*/
uint64_t
zil_max_log_data(zilog_t *zilog, size_t hdrsize)
{
return (zilog->zl_max_block_size - sizeof (zil_chain_t) - hdrsize);
}
/*
* Maximum amount of log space we agree to waste to reduce number of
* WR_NEED_COPY chunks to reduce zl_get_data() overhead (~6%).
*/
static inline uint64_t
zil_max_waste_space(zilog_t *zilog)
{
return (zil_max_log_data(zilog, sizeof (lr_write_t)) / 16);
}
/*
* Maximum amount of write data for WR_COPIED. For correctness, consumers
* must fall back to WR_NEED_COPY if we can't fit the entire record into one
* maximum sized log block, because each WR_COPIED record must fit in a
* single log block. Below that it is a tradeoff of additional memory copy
* and possibly worse log space efficiency vs additional range lock/unlock.
*/
static uint_t zil_maxcopied = 7680;
uint64_t
zil_max_copied_data(zilog_t *zilog)
{
uint64_t max_data = zil_max_log_data(zilog, sizeof (lr_write_t));
return (MIN(max_data, zil_maxcopied));
}
/*
* Estimate space needed in the lwb for the itx. Allocate more lwbs or
* split the itx as needed, but don't touch the actual transaction data.
* Has to be called under zl_issuer_lock to call zil_lwb_write_close()
* to chain more lwbs.
*/
static lwb_t *
zil_lwb_assign(zilog_t *zilog, lwb_t *lwb, itx_t *itx, list_t *ilwbs)
{
itx_t *citx;
lr_t *lr, *clr;
lr_write_t *lrw;
uint64_t dlen, dnow, lwb_sp, reclen, max_log_data;
ASSERT(MUTEX_HELD(&zilog->zl_issuer_lock));
ASSERT3P(lwb, !=, NULL);
ASSERT3P(lwb->lwb_buf, !=, NULL);
zil_lwb_write_open(zilog, lwb);
lr = &itx->itx_lr;
lrw = (lr_write_t *)lr;
/*
* A commit itx doesn't represent any on-disk state; instead
* it's simply used as a place holder on the commit list, and
* provides a mechanism for attaching a "commit waiter" onto the
* correct lwb (such that the waiter can be signalled upon
* completion of that lwb). Thus, we don't process this itx's
* log record if it's a commit itx (these itx's don't have log
* records), and instead link the itx's waiter onto the lwb's
* list of waiters.
*
* For more details, see the comment above zil_commit().
*/
if (lr->lrc_txtype == TX_COMMIT) {
zil_commit_waiter_link_lwb(itx->itx_private, lwb);
list_insert_tail(&lwb->lwb_itxs, itx);
return (lwb);
}
reclen = lr->lrc_reclen;
if (lr->lrc_txtype == TX_WRITE && itx->itx_wr_state == WR_NEED_COPY) {
ASSERT3U(reclen, ==, sizeof (lr_write_t));
dlen = P2ROUNDUP_TYPED(
lrw->lr_length, sizeof (uint64_t), uint64_t);
} else {
ASSERT3U(reclen, >=, sizeof (lr_t));
dlen = 0;
}
ASSERT3U(reclen, <=, zil_max_log_data(zilog, 0));
zilog->zl_cur_used += (reclen + dlen);
cont:
/*
* If this record won't fit in the current log block, start a new one.
* For WR_NEED_COPY optimize layout for minimal number of chunks.
*/
lwb_sp = lwb->lwb_nmax - lwb->lwb_nused;
max_log_data = zil_max_log_data(zilog, sizeof (lr_write_t));
if (reclen > lwb_sp || (reclen + dlen > lwb_sp &&
lwb_sp < zil_max_waste_space(zilog) &&
(dlen % max_log_data == 0 ||
lwb_sp < reclen + dlen % max_log_data))) {
list_insert_tail(ilwbs, lwb);
lwb = zil_lwb_write_close(zilog, lwb, LWB_STATE_OPENED);
if (lwb == NULL)
return (NULL);
lwb_sp = lwb->lwb_nmax - lwb->lwb_nused;
}
/*
* There must be enough space in the log block to hold reclen.
* For WR_COPIED, we need to fit the whole record in one block,
* and reclen is the write record header size + the data size.
* For WR_NEED_COPY, we can create multiple records, splitting
* the data into multiple blocks, so we only need to fit one
* word of data per block; in this case reclen is just the header
* size (no data).
*/
ASSERT3U(reclen + MIN(dlen, sizeof (uint64_t)), <=, lwb_sp);
dnow = MIN(dlen, lwb_sp - reclen);
if (dlen > dnow) {
ASSERT3U(lr->lrc_txtype, ==, TX_WRITE);
ASSERT3U(itx->itx_wr_state, ==, WR_NEED_COPY);
citx = zil_itx_clone(itx);
clr = &citx->itx_lr;
lr_write_t *clrw = (lr_write_t *)clr;
clrw->lr_length = dnow;
lrw->lr_offset += dnow;
lrw->lr_length -= dnow;
} else {
citx = itx;
clr = lr;
}
/*
* We're actually making an entry, so update lrc_seq to be the
* log record sequence number. Note that this is generally not
* equal to the itx sequence number because not all transactions
* are synchronous, and sometimes spa_sync() gets there first.
*/
clr->lrc_seq = ++zilog->zl_lr_seq;
lwb->lwb_nused += reclen + dnow;
ASSERT3U(lwb->lwb_nused, <=, lwb->lwb_nmax);
ASSERT0(P2PHASE(lwb->lwb_nused, sizeof (uint64_t)));
zil_lwb_add_txg(lwb, lr->lrc_txg);
list_insert_tail(&lwb->lwb_itxs, citx);
dlen -= dnow;
if (dlen > 0) {
zilog->zl_cur_used += reclen;
goto cont;
}
if (lr->lrc_txtype == TX_WRITE &&
lr->lrc_txg > spa_freeze_txg(zilog->zl_spa))
txg_wait_synced(zilog->zl_dmu_pool, lr->lrc_txg);
return (lwb);
}
/*
* Fill the actual transaction data into the lwb, following zil_lwb_assign().
* Does not require locking.
*/
static void
zil_lwb_commit(zilog_t *zilog, lwb_t *lwb, itx_t *itx)
{
lr_t *lr, *lrb;
lr_write_t *lrw, *lrwb;
char *lr_buf;
uint64_t dlen, reclen;
lr = &itx->itx_lr;
lrw = (lr_write_t *)lr;
if (lr->lrc_txtype == TX_COMMIT)
return;
if (lr->lrc_txtype == TX_WRITE && itx->itx_wr_state == WR_NEED_COPY) {
dlen = P2ROUNDUP_TYPED(
lrw->lr_length, sizeof (uint64_t), uint64_t);
} else {
dlen = 0;
}
reclen = lr->lrc_reclen;
ASSERT3U(reclen + dlen, <=, lwb->lwb_nused - lwb->lwb_nfilled);
lr_buf = lwb->lwb_buf + lwb->lwb_nfilled;
memcpy(lr_buf, lr, reclen);
lrb = (lr_t *)lr_buf; /* Like lr, but inside lwb. */
lrwb = (lr_write_t *)lrb; /* Like lrw, but inside lwb. */
ZIL_STAT_BUMP(zilog, zil_itx_count);
/*
* If it's a write, fetch the data or get its blkptr as appropriate.
*/
if (lr->lrc_txtype == TX_WRITE) {
if (itx->itx_wr_state == WR_COPIED) {
ZIL_STAT_BUMP(zilog, zil_itx_copied_count);
ZIL_STAT_INCR(zilog, zil_itx_copied_bytes,
lrw->lr_length);
} else {
char *dbuf;
int error;
if (itx->itx_wr_state == WR_NEED_COPY) {
dbuf = lr_buf + reclen;
lrb->lrc_reclen += dlen;
ZIL_STAT_BUMP(zilog, zil_itx_needcopy_count);
ZIL_STAT_INCR(zilog, zil_itx_needcopy_bytes,
dlen);
} else {
ASSERT3S(itx->itx_wr_state, ==, WR_INDIRECT);
dbuf = NULL;
ZIL_STAT_BUMP(zilog, zil_itx_indirect_count);
ZIL_STAT_INCR(zilog, zil_itx_indirect_bytes,
lrw->lr_length);
if (lwb->lwb_child_zio == NULL) {
lwb->lwb_child_zio = zio_root(
zilog->zl_spa, NULL, NULL,
ZIO_FLAG_CANFAIL);
}
}
/*
* The "lwb_child_zio" we pass in will become a child of
* "lwb_write_zio", when one is created, so one will be
* a parent of any zio's created by the "zl_get_data".
* This way "lwb_write_zio" will first wait for children
* block pointers before own writing, and then for their
* writing completion before the vdev cache flushing.
*/
error = zilog->zl_get_data(itx->itx_private,
itx->itx_gen, lrwb, dbuf, lwb,
lwb->lwb_child_zio);
if (dbuf != NULL && error == 0) {
/* Zero any padding bytes in the last block. */
memset((char *)dbuf + lrwb->lr_length, 0,
dlen - lrwb->lr_length);
}
/*
* Typically, the only return values we should see from
* ->zl_get_data() are 0, EIO, ENOENT, EEXIST or
* EALREADY. However, it is also possible to see other
* error values such as ENOSPC or EINVAL from
* dmu_read() -> dnode_hold() -> dnode_hold_impl() or
* ENXIO as well as a multitude of others from the
* block layer through dmu_buf_hold() -> dbuf_read()
* -> zio_wait(), as well as through dmu_read() ->
* dnode_hold() -> dnode_hold_impl() -> dbuf_read() ->
* zio_wait(). When these errors happen, we can assume
* that neither an immediate write nor an indirect
* write occurred, so we need to fall back to
* txg_wait_synced(). This is unusual, so we print to
* dmesg whenever one of these errors occurs.
*/
switch (error) {
case 0:
break;
default:
cmn_err(CE_WARN, "zil_lwb_commit() received "
"unexpected error %d from ->zl_get_data()"
". Falling back to txg_wait_synced().",
error);
zfs_fallthrough;
case EIO:
txg_wait_synced(zilog->zl_dmu_pool,
lr->lrc_txg);
zfs_fallthrough;
case ENOENT:
zfs_fallthrough;
case EEXIST:
zfs_fallthrough;
case EALREADY:
return;
}
}
}
lwb->lwb_nfilled += reclen + dlen;
ASSERT3S(lwb->lwb_nfilled, <=, lwb->lwb_nused);
ASSERT0(P2PHASE(lwb->lwb_nfilled, sizeof (uint64_t)));
}
itx_t *
zil_itx_create(uint64_t txtype, size_t olrsize)
{
size_t itxsize, lrsize;
itx_t *itx;
ASSERT3U(olrsize, >=, sizeof (lr_t));
lrsize = P2ROUNDUP_TYPED(olrsize, sizeof (uint64_t), size_t);
ASSERT3U(lrsize, >=, olrsize);
itxsize = offsetof(itx_t, itx_lr) + lrsize;
itx = zio_data_buf_alloc(itxsize);
itx->itx_lr.lrc_txtype = txtype;
itx->itx_lr.lrc_reclen = lrsize;
itx->itx_lr.lrc_seq = 0; /* defensive */
memset((char *)&itx->itx_lr + olrsize, 0, lrsize - olrsize);
itx->itx_sync = B_TRUE; /* default is synchronous */
itx->itx_callback = NULL;
itx->itx_callback_data = NULL;
itx->itx_size = itxsize;
return (itx);
}
static itx_t *
zil_itx_clone(itx_t *oitx)
{
ASSERT3U(oitx->itx_size, >=, sizeof (itx_t));
ASSERT3U(oitx->itx_size, ==,
offsetof(itx_t, itx_lr) + oitx->itx_lr.lrc_reclen);
itx_t *itx = zio_data_buf_alloc(oitx->itx_size);
memcpy(itx, oitx, oitx->itx_size);
itx->itx_callback = NULL;
itx->itx_callback_data = NULL;
return (itx);
}
void
zil_itx_destroy(itx_t *itx)
{
ASSERT3U(itx->itx_size, >=, sizeof (itx_t));
ASSERT3U(itx->itx_lr.lrc_reclen, ==,
itx->itx_size - offsetof(itx_t, itx_lr));
IMPLY(itx->itx_lr.lrc_txtype == TX_COMMIT, itx->itx_callback == NULL);
IMPLY(itx->itx_callback != NULL, itx->itx_lr.lrc_txtype != TX_COMMIT);
if (itx->itx_callback != NULL)
itx->itx_callback(itx->itx_callback_data);
zio_data_buf_free(itx, itx->itx_size);
}
/*
* Free up the sync and async itxs. The itxs_t has already been detached
* so no locks are needed.
*/
static void
zil_itxg_clean(void *arg)
{
itx_t *itx;
list_t *list;
avl_tree_t *t;
void *cookie;
itxs_t *itxs = arg;
itx_async_node_t *ian;
list = &itxs->i_sync_list;
while ((itx = list_remove_head(list)) != NULL) {
/*
* In the general case, commit itxs will not be found
* here, as they'll be committed to an lwb via
* zil_lwb_assign(), and free'd in that function. Having
* said that, it is still possible for commit itxs to be
* found here, due to the following race:
*
* - a thread calls zil_commit() which assigns the
* commit itx to a per-txg i_sync_list
* - zil_itxg_clean() is called (e.g. via spa_sync())
* while the waiter is still on the i_sync_list
*
* There's nothing to prevent syncing the txg while the
* waiter is on the i_sync_list. This normally doesn't
* happen because spa_sync() is slower than zil_commit(),
* but if zil_commit() calls txg_wait_synced() (e.g.
* because zil_create() or zil_commit_writer_stall() is
* called) we will hit this case.
*/
if (itx->itx_lr.lrc_txtype == TX_COMMIT)
zil_commit_waiter_skip(itx->itx_private);
zil_itx_destroy(itx);
}
cookie = NULL;
t = &itxs->i_async_tree;
while ((ian = avl_destroy_nodes(t, &cookie)) != NULL) {
list = &ian->ia_list;
while ((itx = list_remove_head(list)) != NULL) {
/* commit itxs should never be on the async lists. */
ASSERT3U(itx->itx_lr.lrc_txtype, !=, TX_COMMIT);
zil_itx_destroy(itx);
}
list_destroy(list);
kmem_free(ian, sizeof (itx_async_node_t));
}
avl_destroy(t);
kmem_free(itxs, sizeof (itxs_t));
}
static int
zil_aitx_compare(const void *x1, const void *x2)
{
const uint64_t o1 = ((itx_async_node_t *)x1)->ia_foid;
const uint64_t o2 = ((itx_async_node_t *)x2)->ia_foid;
return (TREE_CMP(o1, o2));
}
/*
* Remove all async itx with the given oid.
*/
void
zil_remove_async(zilog_t *zilog, uint64_t oid)
{
uint64_t otxg, txg;
itx_async_node_t *ian, ian_search;
avl_tree_t *t;
avl_index_t where;
list_t clean_list;
itx_t *itx;
ASSERT(oid != 0);
list_create(&clean_list, sizeof (itx_t), offsetof(itx_t, itx_node));
if (spa_freeze_txg(zilog->zl_spa) != UINT64_MAX) /* ziltest support */
otxg = ZILTEST_TXG;
else
otxg = spa_last_synced_txg(zilog->zl_spa) + 1;
for (txg = otxg; txg < (otxg + TXG_CONCURRENT_STATES); txg++) {
itxg_t *itxg = &zilog->zl_itxg[txg & TXG_MASK];
mutex_enter(&itxg->itxg_lock);
if (itxg->itxg_txg != txg) {
mutex_exit(&itxg->itxg_lock);
continue;
}
/*
* Locate the object node and append its list.
*/
t = &itxg->itxg_itxs->i_async_tree;
ian_search.ia_foid = oid;
ian = avl_find(t, &ian_search, &where);
if (ian != NULL)
list_move_tail(&clean_list, &ian->ia_list);
mutex_exit(&itxg->itxg_lock);
}
while ((itx = list_remove_head(&clean_list)) != NULL) {
/* commit itxs should never be on the async lists. */
ASSERT3U(itx->itx_lr.lrc_txtype, !=, TX_COMMIT);
zil_itx_destroy(itx);
}
list_destroy(&clean_list);
}
void
zil_itx_assign(zilog_t *zilog, itx_t *itx, dmu_tx_t *tx)
{
uint64_t txg;
itxg_t *itxg;
itxs_t *itxs, *clean = NULL;
/*
* Ensure the data of a renamed file is committed before the rename.
*/
if ((itx->itx_lr.lrc_txtype & ~TX_CI) == TX_RENAME)
zil_async_to_sync(zilog, itx->itx_oid);
if (spa_freeze_txg(zilog->zl_spa) != UINT64_MAX)
txg = ZILTEST_TXG;
else
txg = dmu_tx_get_txg(tx);
itxg = &zilog->zl_itxg[txg & TXG_MASK];
mutex_enter(&itxg->itxg_lock);
itxs = itxg->itxg_itxs;
if (itxg->itxg_txg != txg) {
if (itxs != NULL) {
/*
* The zil_clean callback hasn't got around to cleaning
* this itxg. Save the itxs for release below.
* This should be rare.
*/
zfs_dbgmsg("zil_itx_assign: missed itx cleanup for "
"txg %llu", (u_longlong_t)itxg->itxg_txg);
clean = itxg->itxg_itxs;
}
itxg->itxg_txg = txg;
itxs = itxg->itxg_itxs = kmem_zalloc(sizeof (itxs_t),
KM_SLEEP);
list_create(&itxs->i_sync_list, sizeof (itx_t),
offsetof(itx_t, itx_node));
avl_create(&itxs->i_async_tree, zil_aitx_compare,
sizeof (itx_async_node_t),
offsetof(itx_async_node_t, ia_node));
}
if (itx->itx_sync) {
list_insert_tail(&itxs->i_sync_list, itx);
} else {
avl_tree_t *t = &itxs->i_async_tree;
uint64_t foid =
LR_FOID_GET_OBJ(((lr_ooo_t *)&itx->itx_lr)->lr_foid);
itx_async_node_t *ian;
avl_index_t where;
ian = avl_find(t, &foid, &where);
if (ian == NULL) {
ian = kmem_alloc(sizeof (itx_async_node_t),
KM_SLEEP);
list_create(&ian->ia_list, sizeof (itx_t),
offsetof(itx_t, itx_node));
ian->ia_foid = foid;
avl_insert(t, ian, where);
}
list_insert_tail(&ian->ia_list, itx);
}
itx->itx_lr.lrc_txg = dmu_tx_get_txg(tx);
/*
* We don't want to dirty the ZIL using ZILTEST_TXG, because
* zil_clean() will never be called using ZILTEST_TXG. Thus, we
* need to be careful to always dirty the ZIL using the "real"
* TXG (not itxg_txg) even when the SPA is frozen.
*/
zilog_dirty(zilog, dmu_tx_get_txg(tx));
mutex_exit(&itxg->itxg_lock);
/* Release the old itxs now we've dropped the lock */
if (clean != NULL)
zil_itxg_clean(clean);
}
/*
* If there are any in-memory intent log transactions which have now been
* synced then start up a taskq to free them. We should only do this after we
* have written out the uberblocks (i.e. txg has been committed) so that
* don't inadvertently clean out in-memory log records that would be required
* by zil_commit().
*/
void
zil_clean(zilog_t *zilog, uint64_t synced_txg)
{
itxg_t *itxg = &zilog->zl_itxg[synced_txg & TXG_MASK];
itxs_t *clean_me;
ASSERT3U(synced_txg, <, ZILTEST_TXG);
mutex_enter(&itxg->itxg_lock);
if (itxg->itxg_itxs == NULL || itxg->itxg_txg == ZILTEST_TXG) {
mutex_exit(&itxg->itxg_lock);
return;
}
ASSERT3U(itxg->itxg_txg, <=, synced_txg);
ASSERT3U(itxg->itxg_txg, !=, 0);
clean_me = itxg->itxg_itxs;
itxg->itxg_itxs = NULL;
itxg->itxg_txg = 0;
mutex_exit(&itxg->itxg_lock);
/*
* Preferably start a task queue to free up the old itxs but
* if taskq_dispatch can't allocate resources to do that then
* free it in-line. This should be rare. Note, using TQ_SLEEP
* created a bad performance problem.
*/
ASSERT3P(zilog->zl_dmu_pool, !=, NULL);
ASSERT3P(zilog->zl_dmu_pool->dp_zil_clean_taskq, !=, NULL);
taskqid_t id = taskq_dispatch(zilog->zl_dmu_pool->dp_zil_clean_taskq,
zil_itxg_clean, clean_me, TQ_NOSLEEP);
if (id == TASKQID_INVALID)
zil_itxg_clean(clean_me);
}
/*
* This function will traverse the queue of itxs that need to be
* committed, and move them onto the ZIL's zl_itx_commit_list.
*/
static uint64_t
zil_get_commit_list(zilog_t *zilog)
{
uint64_t otxg, txg, wtxg = 0;
list_t *commit_list = &zilog->zl_itx_commit_list;
ASSERT(MUTEX_HELD(&zilog->zl_issuer_lock));
if (spa_freeze_txg(zilog->zl_spa) != UINT64_MAX) /* ziltest support */
otxg = ZILTEST_TXG;
else
otxg = spa_last_synced_txg(zilog->zl_spa) + 1;
/*
* This is inherently racy, since there is nothing to prevent
* the last synced txg from changing. That's okay since we'll
* only commit things in the future.
*/
for (txg = otxg; txg < (otxg + TXG_CONCURRENT_STATES); txg++) {
itxg_t *itxg = &zilog->zl_itxg[txg & TXG_MASK];
mutex_enter(&itxg->itxg_lock);
if (itxg->itxg_txg != txg) {
mutex_exit(&itxg->itxg_lock);
continue;
}
/*
* If we're adding itx records to the zl_itx_commit_list,
* then the zil better be dirty in this "txg". We can assert
* that here since we're holding the itxg_lock which will
* prevent spa_sync from cleaning it. Once we add the itxs
* to the zl_itx_commit_list we must commit it to disk even
* if it's unnecessary (i.e. the txg was synced).
*/
ASSERT(zilog_is_dirty_in_txg(zilog, txg) ||
spa_freeze_txg(zilog->zl_spa) != UINT64_MAX);
list_t *sync_list = &itxg->itxg_itxs->i_sync_list;
if (unlikely(zilog->zl_suspend > 0)) {
/*
* ZIL was just suspended, but we lost the race.
* Allow all earlier itxs to be committed, but ask
* caller to do txg_wait_synced(txg) for any new.
*/
if (!list_is_empty(sync_list))
wtxg = MAX(wtxg, txg);
} else {
list_move_tail(commit_list, sync_list);
}
mutex_exit(&itxg->itxg_lock);
}
return (wtxg);
}
/*
* Move the async itxs for a specified object to commit into sync lists.
*/
void
zil_async_to_sync(zilog_t *zilog, uint64_t foid)
{
uint64_t otxg, txg;
itx_async_node_t *ian, ian_search;
avl_tree_t *t;
avl_index_t where;
if (spa_freeze_txg(zilog->zl_spa) != UINT64_MAX) /* ziltest support */
otxg = ZILTEST_TXG;
else
otxg = spa_last_synced_txg(zilog->zl_spa) + 1;
/*
* This is inherently racy, since there is nothing to prevent
* the last synced txg from changing.
*/
for (txg = otxg; txg < (otxg + TXG_CONCURRENT_STATES); txg++) {
itxg_t *itxg = &zilog->zl_itxg[txg & TXG_MASK];
mutex_enter(&itxg->itxg_lock);
if (itxg->itxg_txg != txg) {
mutex_exit(&itxg->itxg_lock);
continue;
}
/*
* If a foid is specified then find that node and append its
* list. Otherwise walk the tree appending all the lists
* to the sync list. We add to the end rather than the
* beginning to ensure the create has happened.
*/
t = &itxg->itxg_itxs->i_async_tree;
if (foid != 0) {
ian_search.ia_foid = foid;
ian = avl_find(t, &ian_search, &where);
if (ian != NULL) {
list_move_tail(&itxg->itxg_itxs->i_sync_list,
&ian->ia_list);
}
} else {
void *cookie = NULL;
while ((ian = avl_destroy_nodes(t, &cookie)) != NULL) {
list_move_tail(&itxg->itxg_itxs->i_sync_list,
&ian->ia_list);
list_destroy(&ian->ia_list);
kmem_free(ian, sizeof (itx_async_node_t));
}
}
mutex_exit(&itxg->itxg_lock);
}
}
/*
* This function will prune commit itxs that are at the head of the
* commit list (it won't prune past the first non-commit itx), and
* either: a) attach them to the last lwb that's still pending
* completion, or b) skip them altogether.
*
* This is used as a performance optimization to prevent commit itxs
* from generating new lwbs when it's unnecessary to do so.
*/
static void
zil_prune_commit_list(zilog_t *zilog)
{
itx_t *itx;
ASSERT(MUTEX_HELD(&zilog->zl_issuer_lock));
while ((itx = list_head(&zilog->zl_itx_commit_list)) != NULL) {
lr_t *lrc = &itx->itx_lr;
if (lrc->lrc_txtype != TX_COMMIT)
break;
mutex_enter(&zilog->zl_lock);
lwb_t *last_lwb = zilog->zl_last_lwb_opened;
if (last_lwb == NULL ||
last_lwb->lwb_state == LWB_STATE_FLUSH_DONE) {
/*
* All of the itxs this waiter was waiting on
* must have already completed (or there were
* never any itx's for it to wait on), so it's
* safe to skip this waiter and mark it done.
*/
zil_commit_waiter_skip(itx->itx_private);
} else {
zil_commit_waiter_link_lwb(itx->itx_private, last_lwb);
}
mutex_exit(&zilog->zl_lock);
list_remove(&zilog->zl_itx_commit_list, itx);
zil_itx_destroy(itx);
}
IMPLY(itx != NULL, itx->itx_lr.lrc_txtype != TX_COMMIT);
}
static void
zil_commit_writer_stall(zilog_t *zilog)
{
/*
* When zio_alloc_zil() fails to allocate the next lwb block on
* disk, we must call txg_wait_synced() to ensure all of the
* lwbs in the zilog's zl_lwb_list are synced and then freed (in
* zil_sync()), such that any subsequent ZIL writer (i.e. a call
* to zil_process_commit_list()) will have to call zil_create(),
* and start a new ZIL chain.
*
* Since zil_alloc_zil() failed, the lwb that was previously
* issued does not have a pointer to the "next" lwb on disk.
* Thus, if another ZIL writer thread was to allocate the "next"
* on-disk lwb, that block could be leaked in the event of a
* crash (because the previous lwb on-disk would not point to
* it).
*
* We must hold the zilog's zl_issuer_lock while we do this, to
* ensure no new threads enter zil_process_commit_list() until
* all lwb's in the zl_lwb_list have been synced and freed
* (which is achieved via the txg_wait_synced() call).
*/
ASSERT(MUTEX_HELD(&zilog->zl_issuer_lock));
txg_wait_synced(zilog->zl_dmu_pool, 0);
ASSERT(list_is_empty(&zilog->zl_lwb_list));
}
/*
* This function will traverse the commit list, creating new lwbs as
* needed, and committing the itxs from the commit list to these newly
* created lwbs. Additionally, as a new lwb is created, the previous
* lwb will be issued to the zio layer to be written to disk.
*/
static void
zil_process_commit_list(zilog_t *zilog, zil_commit_waiter_t *zcw, list_t *ilwbs)
{
spa_t *spa = zilog->zl_spa;
list_t nolwb_itxs;
list_t nolwb_waiters;
lwb_t *lwb, *plwb;
itx_t *itx;
boolean_t first = B_TRUE;
ASSERT(MUTEX_HELD(&zilog->zl_issuer_lock));
/*
* Return if there's nothing to commit before we dirty the fs by
* calling zil_create().
*/
if (list_is_empty(&zilog->zl_itx_commit_list))
return;
list_create(&nolwb_itxs, sizeof (itx_t), offsetof(itx_t, itx_node));
list_create(&nolwb_waiters, sizeof (zil_commit_waiter_t),
offsetof(zil_commit_waiter_t, zcw_node));
lwb = list_tail(&zilog->zl_lwb_list);
if (lwb == NULL) {
lwb = zil_create(zilog);
} else {
/*
* Activate SPA_FEATURE_ZILSAXATTR for the cases where ZIL will
* have already been created (zl_lwb_list not empty).
*/
zil_commit_activate_saxattr_feature(zilog);
ASSERT(lwb->lwb_state == LWB_STATE_NEW ||
lwb->lwb_state == LWB_STATE_OPENED);
first = (lwb->lwb_state == LWB_STATE_NEW) &&
((plwb = list_prev(&zilog->zl_lwb_list, lwb)) == NULL ||
plwb->lwb_state == LWB_STATE_FLUSH_DONE);
}
while ((itx = list_remove_head(&zilog->zl_itx_commit_list)) != NULL) {
lr_t *lrc = &itx->itx_lr;
uint64_t txg = lrc->lrc_txg;
ASSERT3U(txg, !=, 0);
if (lrc->lrc_txtype == TX_COMMIT) {
DTRACE_PROBE2(zil__process__commit__itx,
zilog_t *, zilog, itx_t *, itx);
} else {
DTRACE_PROBE2(zil__process__normal__itx,
zilog_t *, zilog, itx_t *, itx);
}
boolean_t synced = txg <= spa_last_synced_txg(spa);
boolean_t frozen = txg > spa_freeze_txg(spa);
/*
* If the txg of this itx has already been synced out, then
* we don't need to commit this itx to an lwb. This is
* because the data of this itx will have already been
* written to the main pool. This is inherently racy, and
* it's still ok to commit an itx whose txg has already
* been synced; this will result in a write that's
* unnecessary, but will do no harm.
*
* With that said, we always want to commit TX_COMMIT itxs
* to an lwb, regardless of whether or not that itx's txg
* has been synced out. We do this to ensure any OPENED lwb
* will always have at least one zil_commit_waiter_t linked
* to the lwb.
*
* As a counter-example, if we skipped TX_COMMIT itx's
* whose txg had already been synced, the following
* situation could occur if we happened to be racing with
* spa_sync:
*
* 1. We commit a non-TX_COMMIT itx to an lwb, where the
* itx's txg is 10 and the last synced txg is 9.
* 2. spa_sync finishes syncing out txg 10.
* 3. We move to the next itx in the list, it's a TX_COMMIT
* whose txg is 10, so we skip it rather than committing
* it to the lwb used in (1).
*
* If the itx that is skipped in (3) is the last TX_COMMIT
* itx in the commit list, than it's possible for the lwb
* used in (1) to remain in the OPENED state indefinitely.
*
* To prevent the above scenario from occurring, ensuring
* that once an lwb is OPENED it will transition to ISSUED
* and eventually DONE, we always commit TX_COMMIT itx's to
* an lwb here, even if that itx's txg has already been
* synced.
*
* Finally, if the pool is frozen, we _always_ commit the
* itx. The point of freezing the pool is to prevent data
* from being written to the main pool via spa_sync, and
* instead rely solely on the ZIL to persistently store the
* data; i.e. when the pool is frozen, the last synced txg
* value can't be trusted.
*/
if (frozen || !synced || lrc->lrc_txtype == TX_COMMIT) {
if (lwb != NULL) {
lwb = zil_lwb_assign(zilog, lwb, itx, ilwbs);
if (lwb == NULL) {
list_insert_tail(&nolwb_itxs, itx);
} else if ((zcw->zcw_lwb != NULL &&
zcw->zcw_lwb != lwb) || zcw->zcw_done) {
/*
* Our lwb is done, leave the rest of
* itx list to somebody else who care.
*/
first = B_FALSE;
break;
}
} else {
if (lrc->lrc_txtype == TX_COMMIT) {
zil_commit_waiter_link_nolwb(
itx->itx_private, &nolwb_waiters);
}
list_insert_tail(&nolwb_itxs, itx);
}
} else {
ASSERT3S(lrc->lrc_txtype, !=, TX_COMMIT);
zil_itx_destroy(itx);
}
}
if (lwb == NULL) {
/*
* This indicates zio_alloc_zil() failed to allocate the
* "next" lwb on-disk. When this happens, we must stall
* the ZIL write pipeline; see the comment within
* zil_commit_writer_stall() for more details.
*/
while ((lwb = list_remove_head(ilwbs)) != NULL)
zil_lwb_write_issue(zilog, lwb);
zil_commit_writer_stall(zilog);
/*
* Additionally, we have to signal and mark the "nolwb"
* waiters as "done" here, since without an lwb, we
* can't do this via zil_lwb_flush_vdevs_done() like
* normal.
*/
zil_commit_waiter_t *zcw;
while ((zcw = list_remove_head(&nolwb_waiters)) != NULL)
zil_commit_waiter_skip(zcw);
/*
* And finally, we have to destroy the itx's that
* couldn't be committed to an lwb; this will also call
* the itx's callback if one exists for the itx.
*/
while ((itx = list_remove_head(&nolwb_itxs)) != NULL)
zil_itx_destroy(itx);
} else {
ASSERT(list_is_empty(&nolwb_waiters));
ASSERT3P(lwb, !=, NULL);
ASSERT(lwb->lwb_state == LWB_STATE_NEW ||
lwb->lwb_state == LWB_STATE_OPENED);
/*
* At this point, the ZIL block pointed at by the "lwb"
* variable is in "new" or "opened" state.
*
* If it's "new", then no itxs have been committed to it, so
* there's no point in issuing its zio (i.e. it's "empty").
*
* If it's "opened", then it contains one or more itxs that
* eventually need to be committed to stable storage. In
* this case we intentionally do not issue the lwb's zio
* to disk yet, and instead rely on one of the following
* two mechanisms for issuing the zio:
*
* 1. Ideally, there will be more ZIL activity occurring on
* the system, such that this function will be immediately
* called again by different thread and this lwb will be
* closed by zil_lwb_assign(). This way, the lwb will be
* "full" when it is issued to disk, and we'll make use of
* the lwb's size the best we can.
*
* 2. If there isn't sufficient ZIL activity occurring on
* the system, zil_commit_waiter() will close it and issue
* the zio. If this occurs, the lwb is not guaranteed
* to be "full" by the time its zio is issued, and means
* the size of the lwb was "too large" given the amount
* of ZIL activity occurring on the system at that time.
*
* We do this for a couple of reasons:
*
* 1. To try and reduce the number of IOPs needed to
* write the same number of itxs. If an lwb has space
* available in its buffer for more itxs, and more itxs
* will be committed relatively soon (relative to the
* latency of performing a write), then it's beneficial
* to wait for these "next" itxs. This way, more itxs
* can be committed to stable storage with fewer writes.
*
* 2. To try and use the largest lwb block size that the
* incoming rate of itxs can support. Again, this is to
* try and pack as many itxs into as few lwbs as
* possible, without significantly impacting the latency
* of each individual itx.
*
* If we had no already running or open LWBs, it can be
* the workload is single-threaded. And if the ZIL write
* latency is very small or if the LWB is almost full, it
* may be cheaper to bypass the delay.
*/
if (lwb->lwb_state == LWB_STATE_OPENED && first) {
hrtime_t sleep = zilog->zl_last_lwb_latency *
zfs_commit_timeout_pct / 100;
if (sleep < zil_min_commit_timeout ||
lwb->lwb_nmax - lwb->lwb_nused <
lwb->lwb_nmax / 8) {
list_insert_tail(ilwbs, lwb);
lwb = zil_lwb_write_close(zilog, lwb,
LWB_STATE_NEW);
zilog->zl_cur_used = 0;
if (lwb == NULL) {
while ((lwb = list_remove_head(ilwbs))
!= NULL)
zil_lwb_write_issue(zilog, lwb);
zil_commit_writer_stall(zilog);
}
}
}
}
}
/*
* This function is responsible for ensuring the passed in commit waiter
* (and associated commit itx) is committed to an lwb. If the waiter is
* not already committed to an lwb, all itxs in the zilog's queue of
* itxs will be processed. The assumption is the passed in waiter's
* commit itx will found in the queue just like the other non-commit
* itxs, such that when the entire queue is processed, the waiter will
* have been committed to an lwb.
*
* The lwb associated with the passed in waiter is not guaranteed to
* have been issued by the time this function completes. If the lwb is
* not issued, we rely on future calls to zil_commit_writer() to issue
* the lwb, or the timeout mechanism found in zil_commit_waiter().
*/
static uint64_t
zil_commit_writer(zilog_t *zilog, zil_commit_waiter_t *zcw)
{
list_t ilwbs;
lwb_t *lwb;
uint64_t wtxg = 0;
ASSERT(!MUTEX_HELD(&zilog->zl_lock));
ASSERT(spa_writeable(zilog->zl_spa));
list_create(&ilwbs, sizeof (lwb_t), offsetof(lwb_t, lwb_issue_node));
mutex_enter(&zilog->zl_issuer_lock);
if (zcw->zcw_lwb != NULL || zcw->zcw_done) {
/*
* It's possible that, while we were waiting to acquire
* the "zl_issuer_lock", another thread committed this
* waiter to an lwb. If that occurs, we bail out early,
* without processing any of the zilog's queue of itxs.
*
* On certain workloads and system configurations, the
* "zl_issuer_lock" can become highly contended. In an
* attempt to reduce this contention, we immediately drop
* the lock if the waiter has already been processed.
*
* We've measured this optimization to reduce CPU spent
* contending on this lock by up to 5%, using a system
* with 32 CPUs, low latency storage (~50 usec writes),
* and 1024 threads performing sync writes.
*/
goto out;
}
ZIL_STAT_BUMP(zilog, zil_commit_writer_count);
wtxg = zil_get_commit_list(zilog);
zil_prune_commit_list(zilog);
zil_process_commit_list(zilog, zcw, &ilwbs);
out:
mutex_exit(&zilog->zl_issuer_lock);
while ((lwb = list_remove_head(&ilwbs)) != NULL)
zil_lwb_write_issue(zilog, lwb);
list_destroy(&ilwbs);
return (wtxg);
}
static void
zil_commit_waiter_timeout(zilog_t *zilog, zil_commit_waiter_t *zcw)
{
ASSERT(!MUTEX_HELD(&zilog->zl_issuer_lock));
ASSERT(MUTEX_HELD(&zcw->zcw_lock));
ASSERT3B(zcw->zcw_done, ==, B_FALSE);
lwb_t *lwb = zcw->zcw_lwb;
ASSERT3P(lwb, !=, NULL);
ASSERT3S(lwb->lwb_state, !=, LWB_STATE_NEW);
/*
* If the lwb has already been issued by another thread, we can
* immediately return since there's no work to be done (the
* point of this function is to issue the lwb). Additionally, we
* do this prior to acquiring the zl_issuer_lock, to avoid
* acquiring it when it's not necessary to do so.
*/
if (lwb->lwb_state != LWB_STATE_OPENED)
return;
/*
* In order to call zil_lwb_write_close() we must hold the
* zilog's "zl_issuer_lock". We can't simply acquire that lock,
* since we're already holding the commit waiter's "zcw_lock",
* and those two locks are acquired in the opposite order
* elsewhere.
*/
mutex_exit(&zcw->zcw_lock);
mutex_enter(&zilog->zl_issuer_lock);
mutex_enter(&zcw->zcw_lock);
/*
* Since we just dropped and re-acquired the commit waiter's
* lock, we have to re-check to see if the waiter was marked
* "done" during that process. If the waiter was marked "done",
* the "lwb" pointer is no longer valid (it can be free'd after
* the waiter is marked "done"), so without this check we could
* wind up with a use-after-free error below.
*/
if (zcw->zcw_done) {
mutex_exit(&zilog->zl_issuer_lock);
return;
}
ASSERT3P(lwb, ==, zcw->zcw_lwb);
/*
* We've already checked this above, but since we hadn't acquired
* the zilog's zl_issuer_lock, we have to perform this check a
* second time while holding the lock.
*
* We don't need to hold the zl_lock since the lwb cannot transition
* from OPENED to CLOSED while we hold the zl_issuer_lock. The lwb
* _can_ transition from CLOSED to DONE, but it's OK to race with
* that transition since we treat the lwb the same, whether it's in
* the CLOSED, ISSUED or DONE states.
*
* The important thing, is we treat the lwb differently depending on
* if it's OPENED or CLOSED, and block any other threads that might
* attempt to close/issue this lwb. For that reason we hold the
* zl_issuer_lock when checking the lwb_state; we must not call
* zil_lwb_write_close() if the lwb had already been closed/issued.
*
* See the comment above the lwb_state_t structure definition for
* more details on the lwb states, and locking requirements.
*/
if (lwb->lwb_state != LWB_STATE_OPENED) {
mutex_exit(&zilog->zl_issuer_lock);
return;
}
/*
* We do not need zcw_lock once we hold zl_issuer_lock and know lwb
* is still open. But we have to drop it to avoid a deadlock in case
* callback of zio issued by zil_lwb_write_issue() try to get it,
* while zil_lwb_write_issue() is blocked on attempt to issue next
* lwb it found in LWB_STATE_READY state.
*/
mutex_exit(&zcw->zcw_lock);
/*
* As described in the comments above zil_commit_waiter() and
* zil_process_commit_list(), we need to issue this lwb's zio
* since we've reached the commit waiter's timeout and it still
* hasn't been issued.
*/
lwb_t *nlwb = zil_lwb_write_close(zilog, lwb, LWB_STATE_NEW);
ASSERT3S(lwb->lwb_state, ==, LWB_STATE_CLOSED);
/*
* Since the lwb's zio hadn't been issued by the time this thread
* reached its timeout, we reset the zilog's "zl_cur_used" field
* to influence the zil block size selection algorithm.
*
* By having to issue the lwb's zio here, it means the size of the
* lwb was too large, given the incoming throughput of itxs. By
* setting "zl_cur_used" to zero, we communicate this fact to the
* block size selection algorithm, so it can take this information
* into account, and potentially select a smaller size for the
* next lwb block that is allocated.
*/
zilog->zl_cur_used = 0;
if (nlwb == NULL) {
/*
* When zil_lwb_write_close() returns NULL, this
* indicates zio_alloc_zil() failed to allocate the
* "next" lwb on-disk. When this occurs, the ZIL write
* pipeline must be stalled; see the comment within the
* zil_commit_writer_stall() function for more details.
*/
zil_lwb_write_issue(zilog, lwb);
zil_commit_writer_stall(zilog);
mutex_exit(&zilog->zl_issuer_lock);
} else {
mutex_exit(&zilog->zl_issuer_lock);
zil_lwb_write_issue(zilog, lwb);
}
mutex_enter(&zcw->zcw_lock);
}
/*
* This function is responsible for performing the following two tasks:
*
* 1. its primary responsibility is to block until the given "commit
* waiter" is considered "done".
*
* 2. its secondary responsibility is to issue the zio for the lwb that
* the given "commit waiter" is waiting on, if this function has
* waited "long enough" and the lwb is still in the "open" state.
*
* Given a sufficient amount of itxs being generated and written using
* the ZIL, the lwb's zio will be issued via the zil_lwb_assign()
* function. If this does not occur, this secondary responsibility will
* ensure the lwb is issued even if there is not other synchronous
* activity on the system.
*
* For more details, see zil_process_commit_list(); more specifically,
* the comment at the bottom of that function.
*/
static void
zil_commit_waiter(zilog_t *zilog, zil_commit_waiter_t *zcw)
{
ASSERT(!MUTEX_HELD(&zilog->zl_lock));
ASSERT(!MUTEX_HELD(&zilog->zl_issuer_lock));
ASSERT(spa_writeable(zilog->zl_spa));
mutex_enter(&zcw->zcw_lock);
/*
* The timeout is scaled based on the lwb latency to avoid
* significantly impacting the latency of each individual itx.
* For more details, see the comment at the bottom of the
* zil_process_commit_list() function.
*/
int pct = MAX(zfs_commit_timeout_pct, 1);
hrtime_t sleep = (zilog->zl_last_lwb_latency * pct) / 100;
hrtime_t wakeup = gethrtime() + sleep;
boolean_t timedout = B_FALSE;
while (!zcw->zcw_done) {
ASSERT(MUTEX_HELD(&zcw->zcw_lock));
lwb_t *lwb = zcw->zcw_lwb;
/*
* Usually, the waiter will have a non-NULL lwb field here,
* but it's possible for it to be NULL as a result of
* zil_commit() racing with spa_sync().
*
* When zil_clean() is called, it's possible for the itxg
* list (which may be cleaned via a taskq) to contain
* commit itxs. When this occurs, the commit waiters linked
* off of these commit itxs will not be committed to an
* lwb. Additionally, these commit waiters will not be
* marked done until zil_commit_waiter_skip() is called via
* zil_itxg_clean().
*
* Thus, it's possible for this commit waiter (i.e. the
* "zcw" variable) to be found in this "in between" state;
* where it's "zcw_lwb" field is NULL, and it hasn't yet
* been skipped, so it's "zcw_done" field is still B_FALSE.
*/
IMPLY(lwb != NULL, lwb->lwb_state != LWB_STATE_NEW);
if (lwb != NULL && lwb->lwb_state == LWB_STATE_OPENED) {
ASSERT3B(timedout, ==, B_FALSE);
/*
* If the lwb hasn't been issued yet, then we
* need to wait with a timeout, in case this
* function needs to issue the lwb after the
* timeout is reached; responsibility (2) from
* the comment above this function.
*/
int rc = cv_timedwait_hires(&zcw->zcw_cv,
&zcw->zcw_lock, wakeup, USEC2NSEC(1),
CALLOUT_FLAG_ABSOLUTE);
if (rc != -1 || zcw->zcw_done)
continue;
timedout = B_TRUE;
zil_commit_waiter_timeout(zilog, zcw);
if (!zcw->zcw_done) {
/*
* If the commit waiter has already been
* marked "done", it's possible for the
* waiter's lwb structure to have already
* been freed. Thus, we can only reliably
* make these assertions if the waiter
* isn't done.
*/
ASSERT3P(lwb, ==, zcw->zcw_lwb);
ASSERT3S(lwb->lwb_state, !=, LWB_STATE_OPENED);
}
} else {
/*
* If the lwb isn't open, then it must have already
* been issued. In that case, there's no need to
* use a timeout when waiting for the lwb to
* complete.
*
* Additionally, if the lwb is NULL, the waiter
* will soon be signaled and marked done via
* zil_clean() and zil_itxg_clean(), so no timeout
* is required.
*/
IMPLY(lwb != NULL,
lwb->lwb_state == LWB_STATE_CLOSED ||
lwb->lwb_state == LWB_STATE_READY ||
lwb->lwb_state == LWB_STATE_ISSUED ||
lwb->lwb_state == LWB_STATE_WRITE_DONE ||
lwb->lwb_state == LWB_STATE_FLUSH_DONE);
cv_wait(&zcw->zcw_cv, &zcw->zcw_lock);
}
}
mutex_exit(&zcw->zcw_lock);
}
static zil_commit_waiter_t *
zil_alloc_commit_waiter(void)
{
zil_commit_waiter_t *zcw = kmem_cache_alloc(zil_zcw_cache, KM_SLEEP);
cv_init(&zcw->zcw_cv, NULL, CV_DEFAULT, NULL);
mutex_init(&zcw->zcw_lock, NULL, MUTEX_DEFAULT, NULL);
list_link_init(&zcw->zcw_node);
zcw->zcw_lwb = NULL;
zcw->zcw_done = B_FALSE;
zcw->zcw_zio_error = 0;
return (zcw);
}
static void
zil_free_commit_waiter(zil_commit_waiter_t *zcw)
{
ASSERT(!list_link_active(&zcw->zcw_node));
ASSERT3P(zcw->zcw_lwb, ==, NULL);
ASSERT3B(zcw->zcw_done, ==, B_TRUE);
mutex_destroy(&zcw->zcw_lock);
cv_destroy(&zcw->zcw_cv);
kmem_cache_free(zil_zcw_cache, zcw);
}
/*
* This function is used to create a TX_COMMIT itx and assign it. This
* way, it will be linked into the ZIL's list of synchronous itxs, and
* then later committed to an lwb (or skipped) when
* zil_process_commit_list() is called.
*/
static void
zil_commit_itx_assign(zilog_t *zilog, zil_commit_waiter_t *zcw)
{
dmu_tx_t *tx = dmu_tx_create(zilog->zl_os);
/*
* Since we are not going to create any new dirty data, and we
* can even help with clearing the existing dirty data, we
* should not be subject to the dirty data based delays. We
* use TXG_NOTHROTTLE to bypass the delay mechanism.
*/
VERIFY0(dmu_tx_assign(tx, TXG_WAIT | TXG_NOTHROTTLE));
itx_t *itx = zil_itx_create(TX_COMMIT, sizeof (lr_t));
itx->itx_sync = B_TRUE;
itx->itx_private = zcw;
zil_itx_assign(zilog, itx, tx);
dmu_tx_commit(tx);
}
/*
* Commit ZFS Intent Log transactions (itxs) to stable storage.
*
* When writing ZIL transactions to the on-disk representation of the
* ZIL, the itxs are committed to a Log Write Block (lwb). Multiple
* itxs can be committed to a single lwb. Once a lwb is written and
* committed to stable storage (i.e. the lwb is written, and vdevs have
* been flushed), each itx that was committed to that lwb is also
* considered to be committed to stable storage.
*
* When an itx is committed to an lwb, the log record (lr_t) contained
* by the itx is copied into the lwb's zio buffer, and once this buffer
* is written to disk, it becomes an on-disk ZIL block.
*
* As itxs are generated, they're inserted into the ZIL's queue of
* uncommitted itxs. The semantics of zil_commit() are such that it will
* block until all itxs that were in the queue when it was called, are
* committed to stable storage.
*
* If "foid" is zero, this means all "synchronous" and "asynchronous"
* itxs, for all objects in the dataset, will be committed to stable
* storage prior to zil_commit() returning. If "foid" is non-zero, all
* "synchronous" itxs for all objects, but only "asynchronous" itxs
* that correspond to the foid passed in, will be committed to stable
* storage prior to zil_commit() returning.
*
* Generally speaking, when zil_commit() is called, the consumer doesn't
* actually care about _all_ of the uncommitted itxs. Instead, they're
* simply trying to waiting for a specific itx to be committed to disk,
* but the interface(s) for interacting with the ZIL don't allow such
* fine-grained communication. A better interface would allow a consumer
* to create and assign an itx, and then pass a reference to this itx to
* zil_commit(); such that zil_commit() would return as soon as that
* specific itx was committed to disk (instead of waiting for _all_
* itxs to be committed).
*
* When a thread calls zil_commit() a special "commit itx" will be
* generated, along with a corresponding "waiter" for this commit itx.
* zil_commit() will wait on this waiter's CV, such that when the waiter
* is marked done, and signaled, zil_commit() will return.
*
* This commit itx is inserted into the queue of uncommitted itxs. This
* provides an easy mechanism for determining which itxs were in the
* queue prior to zil_commit() having been called, and which itxs were
* added after zil_commit() was called.
*
* The commit itx is special; it doesn't have any on-disk representation.
* When a commit itx is "committed" to an lwb, the waiter associated
* with it is linked onto the lwb's list of waiters. Then, when that lwb
* completes, each waiter on the lwb's list is marked done and signaled
* -- allowing the thread waiting on the waiter to return from zil_commit().
*
* It's important to point out a few critical factors that allow us
* to make use of the commit itxs, commit waiters, per-lwb lists of
* commit waiters, and zio completion callbacks like we're doing:
*
* 1. The list of waiters for each lwb is traversed, and each commit
* waiter is marked "done" and signaled, in the zio completion
* callback of the lwb's zio[*].
*
* * Actually, the waiters are signaled in the zio completion
* callback of the root zio for the DKIOCFLUSHWRITECACHE commands
* that are sent to the vdevs upon completion of the lwb zio.
*
* 2. When the itxs are inserted into the ZIL's queue of uncommitted
* itxs, the order in which they are inserted is preserved[*]; as
* itxs are added to the queue, they are added to the tail of
* in-memory linked lists.
*
* When committing the itxs to lwbs (to be written to disk), they
* are committed in the same order in which the itxs were added to
* the uncommitted queue's linked list(s); i.e. the linked list of
* itxs to commit is traversed from head to tail, and each itx is
* committed to an lwb in that order.
*
* * To clarify:
*
* - the order of "sync" itxs is preserved w.r.t. other
* "sync" itxs, regardless of the corresponding objects.
* - the order of "async" itxs is preserved w.r.t. other
* "async" itxs corresponding to the same object.
* - the order of "async" itxs is *not* preserved w.r.t. other
* "async" itxs corresponding to different objects.
* - the order of "sync" itxs w.r.t. "async" itxs (or vice
* versa) is *not* preserved, even for itxs that correspond
* to the same object.
*
* For more details, see: zil_itx_assign(), zil_async_to_sync(),
* zil_get_commit_list(), and zil_process_commit_list().
*
* 3. The lwbs represent a linked list of blocks on disk. Thus, any
* lwb cannot be considered committed to stable storage, until its
* "previous" lwb is also committed to stable storage. This fact,
* coupled with the fact described above, means that itxs are
* committed in (roughly) the order in which they were generated.
* This is essential because itxs are dependent on prior itxs.
* Thus, we *must not* deem an itx as being committed to stable
* storage, until *all* prior itxs have also been committed to
* stable storage.
*
* To enforce this ordering of lwb zio's, while still leveraging as
* much of the underlying storage performance as possible, we rely
* on two fundamental concepts:
*
* 1. The creation and issuance of lwb zio's is protected by
* the zilog's "zl_issuer_lock", which ensures only a single
* thread is creating and/or issuing lwb's at a time
* 2. The "previous" lwb is a child of the "current" lwb
* (leveraging the zio parent-child dependency graph)
*
* By relying on this parent-child zio relationship, we can have
* many lwb zio's concurrently issued to the underlying storage,
* but the order in which they complete will be the same order in
* which they were created.
*/
void
zil_commit(zilog_t *zilog, uint64_t foid)
{
/*
* We should never attempt to call zil_commit on a snapshot for
* a couple of reasons:
*
* 1. A snapshot may never be modified, thus it cannot have any
* in-flight itxs that would have modified the dataset.
*
* 2. By design, when zil_commit() is called, a commit itx will
* be assigned to this zilog; as a result, the zilog will be
* dirtied. We must not dirty the zilog of a snapshot; there's
* checks in the code that enforce this invariant, and will
* cause a panic if it's not upheld.
*/
ASSERT3B(dmu_objset_is_snapshot(zilog->zl_os), ==, B_FALSE);
if (zilog->zl_sync == ZFS_SYNC_DISABLED)
return;
if (!spa_writeable(zilog->zl_spa)) {
/*
* If the SPA is not writable, there should never be any
* pending itxs waiting to be committed to disk. If that
* weren't true, we'd skip writing those itxs out, and
* would break the semantics of zil_commit(); thus, we're
* verifying that truth before we return to the caller.
*/
ASSERT(list_is_empty(&zilog->zl_lwb_list));
ASSERT3P(zilog->zl_last_lwb_opened, ==, NULL);
for (int i = 0; i < TXG_SIZE; i++)
ASSERT3P(zilog->zl_itxg[i].itxg_itxs, ==, NULL);
return;
}
/*
* If the ZIL is suspended, we don't want to dirty it by calling
* zil_commit_itx_assign() below, nor can we write out
* lwbs like would be done in zil_commit_write(). Thus, we
* simply rely on txg_wait_synced() to maintain the necessary
* semantics, and avoid calling those functions altogether.
*/
if (zilog->zl_suspend > 0) {
txg_wait_synced(zilog->zl_dmu_pool, 0);
return;
}
zil_commit_impl(zilog, foid);
}
void
zil_commit_impl(zilog_t *zilog, uint64_t foid)
{
ZIL_STAT_BUMP(zilog, zil_commit_count);
/*
* Move the "async" itxs for the specified foid to the "sync"
* queues, such that they will be later committed (or skipped)
* to an lwb when zil_process_commit_list() is called.
*
* Since these "async" itxs must be committed prior to this
* call to zil_commit returning, we must perform this operation
* before we call zil_commit_itx_assign().
*/
zil_async_to_sync(zilog, foid);
/*
* We allocate a new "waiter" structure which will initially be
* linked to the commit itx using the itx's "itx_private" field.
* Since the commit itx doesn't represent any on-disk state,
* when it's committed to an lwb, rather than copying the its
* lr_t into the lwb's buffer, the commit itx's "waiter" will be
* added to the lwb's list of waiters. Then, when the lwb is
* committed to stable storage, each waiter in the lwb's list of
* waiters will be marked "done", and signalled.
*
* We must create the waiter and assign the commit itx prior to
* calling zil_commit_writer(), or else our specific commit itx
* is not guaranteed to be committed to an lwb prior to calling
* zil_commit_waiter().
*/
zil_commit_waiter_t *zcw = zil_alloc_commit_waiter();
zil_commit_itx_assign(zilog, zcw);
uint64_t wtxg = zil_commit_writer(zilog, zcw);
zil_commit_waiter(zilog, zcw);
if (zcw->zcw_zio_error != 0) {
/*
* If there was an error writing out the ZIL blocks that
* this thread is waiting on, then we fallback to
* relying on spa_sync() to write out the data this
* thread is waiting on. Obviously this has performance
* implications, but the expectation is for this to be
* an exceptional case, and shouldn't occur often.
*/
DTRACE_PROBE2(zil__commit__io__error,
zilog_t *, zilog, zil_commit_waiter_t *, zcw);
txg_wait_synced(zilog->zl_dmu_pool, 0);
} else if (wtxg != 0) {
txg_wait_synced(zilog->zl_dmu_pool, wtxg);
}
zil_free_commit_waiter(zcw);
}
/*
* Called in syncing context to free committed log blocks and update log header.
*/
void
zil_sync(zilog_t *zilog, dmu_tx_t *tx)
{
zil_header_t *zh = zil_header_in_syncing_context(zilog);
uint64_t txg = dmu_tx_get_txg(tx);
spa_t *spa = zilog->zl_spa;
uint64_t *replayed_seq = &zilog->zl_replayed_seq[txg & TXG_MASK];
lwb_t *lwb;
/*
* We don't zero out zl_destroy_txg, so make sure we don't try
* to destroy it twice.
*/
if (spa_sync_pass(spa) != 1)
return;
zil_lwb_flush_wait_all(zilog, txg);
mutex_enter(&zilog->zl_lock);
ASSERT(zilog->zl_stop_sync == 0);
if (*replayed_seq != 0) {
ASSERT(zh->zh_replay_seq < *replayed_seq);
zh->zh_replay_seq = *replayed_seq;
*replayed_seq = 0;
}
if (zilog->zl_destroy_txg == txg) {
blkptr_t blk = zh->zh_log;
dsl_dataset_t *ds = dmu_objset_ds(zilog->zl_os);
ASSERT(list_is_empty(&zilog->zl_lwb_list));
memset(zh, 0, sizeof (zil_header_t));
memset(zilog->zl_replayed_seq, 0,
sizeof (zilog->zl_replayed_seq));
if (zilog->zl_keep_first) {
/*
* If this block was part of log chain that couldn't
* be claimed because a device was missing during
* zil_claim(), but that device later returns,
* then this block could erroneously appear valid.
* To guard against this, assign a new GUID to the new
* log chain so it doesn't matter what blk points to.
*/
zil_init_log_chain(zilog, &blk);
zh->zh_log = blk;
} else {
/*
* A destroyed ZIL chain can't contain any TX_SETSAXATTR
* records. So, deactivate the feature for this dataset.
* We activate it again when we start a new ZIL chain.
*/
if (dsl_dataset_feature_is_active(ds,
SPA_FEATURE_ZILSAXATTR))
dsl_dataset_deactivate_feature(ds,
SPA_FEATURE_ZILSAXATTR, tx);
}
}
while ((lwb = list_head(&zilog->zl_lwb_list)) != NULL) {
zh->zh_log = lwb->lwb_blk;
if (lwb->lwb_state != LWB_STATE_FLUSH_DONE ||
lwb->lwb_alloc_txg > txg || lwb->lwb_max_txg > txg)
break;
list_remove(&zilog->zl_lwb_list, lwb);
if (!BP_IS_HOLE(&lwb->lwb_blk))
zio_free(spa, txg, &lwb->lwb_blk);
zil_free_lwb(zilog, lwb);
/*
* If we don't have anything left in the lwb list then
* we've had an allocation failure and we need to zero
* out the zil_header blkptr so that we don't end
* up freeing the same block twice.
*/
if (list_is_empty(&zilog->zl_lwb_list))
BP_ZERO(&zh->zh_log);
}
mutex_exit(&zilog->zl_lock);
}
static int
zil_lwb_cons(void *vbuf, void *unused, int kmflag)
{
(void) unused, (void) kmflag;
lwb_t *lwb = vbuf;
list_create(&lwb->lwb_itxs, sizeof (itx_t), offsetof(itx_t, itx_node));
list_create(&lwb->lwb_waiters, sizeof (zil_commit_waiter_t),
offsetof(zil_commit_waiter_t, zcw_node));
avl_create(&lwb->lwb_vdev_tree, zil_lwb_vdev_compare,
sizeof (zil_vdev_node_t), offsetof(zil_vdev_node_t, zv_node));
mutex_init(&lwb->lwb_vdev_lock, NULL, MUTEX_DEFAULT, NULL);
return (0);
}
static void
zil_lwb_dest(void *vbuf, void *unused)
{
(void) unused;
lwb_t *lwb = vbuf;
mutex_destroy(&lwb->lwb_vdev_lock);
avl_destroy(&lwb->lwb_vdev_tree);
list_destroy(&lwb->lwb_waiters);
list_destroy(&lwb->lwb_itxs);
}
void
zil_init(void)
{
zil_lwb_cache = kmem_cache_create("zil_lwb_cache",
sizeof (lwb_t), 0, zil_lwb_cons, zil_lwb_dest, NULL, NULL, NULL, 0);
zil_zcw_cache = kmem_cache_create("zil_zcw_cache",
sizeof (zil_commit_waiter_t), 0, NULL, NULL, NULL, NULL, NULL, 0);
zil_sums_init(&zil_sums_global);
zil_kstats_global = kstat_create("zfs", 0, "zil", "misc",
KSTAT_TYPE_NAMED, sizeof (zil_stats) / sizeof (kstat_named_t),
KSTAT_FLAG_VIRTUAL);
if (zil_kstats_global != NULL) {
zil_kstats_global->ks_data = &zil_stats;
zil_kstats_global->ks_update = zil_kstats_global_update;
zil_kstats_global->ks_private = NULL;
kstat_install(zil_kstats_global);
}
}
void
zil_fini(void)
{
kmem_cache_destroy(zil_zcw_cache);
kmem_cache_destroy(zil_lwb_cache);
if (zil_kstats_global != NULL) {
kstat_delete(zil_kstats_global);
zil_kstats_global = NULL;
}
zil_sums_fini(&zil_sums_global);
}
void
zil_set_sync(zilog_t *zilog, uint64_t sync)
{
zilog->zl_sync = sync;
}
void
zil_set_logbias(zilog_t *zilog, uint64_t logbias)
{
zilog->zl_logbias = logbias;
}
zilog_t *
zil_alloc(objset_t *os, zil_header_t *zh_phys)
{
zilog_t *zilog;
zilog = kmem_zalloc(sizeof (zilog_t), KM_SLEEP);
zilog->zl_header = zh_phys;
zilog->zl_os = os;
zilog->zl_spa = dmu_objset_spa(os);
zilog->zl_dmu_pool = dmu_objset_pool(os);
zilog->zl_destroy_txg = TXG_INITIAL - 1;
zilog->zl_logbias = dmu_objset_logbias(os);
zilog->zl_sync = dmu_objset_syncprop(os);
zilog->zl_dirty_max_txg = 0;
zilog->zl_last_lwb_opened = NULL;
zilog->zl_last_lwb_latency = 0;
zilog->zl_max_block_size = zil_maxblocksize;
mutex_init(&zilog->zl_lock, NULL, MUTEX_DEFAULT, NULL);
mutex_init(&zilog->zl_issuer_lock, NULL, MUTEX_DEFAULT, NULL);
mutex_init(&zilog->zl_lwb_io_lock, NULL, MUTEX_DEFAULT, NULL);
for (int i = 0; i < TXG_SIZE; i++) {
mutex_init(&zilog->zl_itxg[i].itxg_lock, NULL,
MUTEX_DEFAULT, NULL);
}
list_create(&zilog->zl_lwb_list, sizeof (lwb_t),
offsetof(lwb_t, lwb_node));
list_create(&zilog->zl_itx_commit_list, sizeof (itx_t),
offsetof(itx_t, itx_node));
cv_init(&zilog->zl_cv_suspend, NULL, CV_DEFAULT, NULL);
cv_init(&zilog->zl_lwb_io_cv, NULL, CV_DEFAULT, NULL);
return (zilog);
}
void
zil_free(zilog_t *zilog)
{
int i;
zilog->zl_stop_sync = 1;
ASSERT0(zilog->zl_suspend);
ASSERT0(zilog->zl_suspending);
ASSERT(list_is_empty(&zilog->zl_lwb_list));
list_destroy(&zilog->zl_lwb_list);
ASSERT(list_is_empty(&zilog->zl_itx_commit_list));
list_destroy(&zilog->zl_itx_commit_list);
for (i = 0; i < TXG_SIZE; i++) {
/*
* It's possible for an itx to be generated that doesn't dirty
* a txg (e.g. ztest TX_TRUNCATE). So there's no zil_clean()
* callback to remove the entry. We remove those here.
*
* Also free up the ziltest itxs.
*/
if (zilog->zl_itxg[i].itxg_itxs)
zil_itxg_clean(zilog->zl_itxg[i].itxg_itxs);
mutex_destroy(&zilog->zl_itxg[i].itxg_lock);
}
mutex_destroy(&zilog->zl_issuer_lock);
mutex_destroy(&zilog->zl_lock);
mutex_destroy(&zilog->zl_lwb_io_lock);
cv_destroy(&zilog->zl_cv_suspend);
cv_destroy(&zilog->zl_lwb_io_cv);
kmem_free(zilog, sizeof (zilog_t));
}
/*
* Open an intent log.
*/
zilog_t *
zil_open(objset_t *os, zil_get_data_t *get_data, zil_sums_t *zil_sums)
{
zilog_t *zilog = dmu_objset_zil(os);
ASSERT3P(zilog->zl_get_data, ==, NULL);
ASSERT3P(zilog->zl_last_lwb_opened, ==, NULL);
ASSERT(list_is_empty(&zilog->zl_lwb_list));
zilog->zl_get_data = get_data;
zilog->zl_sums = zil_sums;
return (zilog);
}
/*
* Close an intent log.
*/
void
zil_close(zilog_t *zilog)
{
lwb_t *lwb;
uint64_t txg;
if (!dmu_objset_is_snapshot(zilog->zl_os)) {
zil_commit(zilog, 0);
} else {
ASSERT(list_is_empty(&zilog->zl_lwb_list));
ASSERT0(zilog->zl_dirty_max_txg);
ASSERT3B(zilog_is_dirty(zilog), ==, B_FALSE);
}
mutex_enter(&zilog->zl_lock);
txg = zilog->zl_dirty_max_txg;
lwb = list_tail(&zilog->zl_lwb_list);
if (lwb != NULL) {
txg = MAX(txg, lwb->lwb_alloc_txg);
txg = MAX(txg, lwb->lwb_max_txg);
}
mutex_exit(&zilog->zl_lock);
/*
* zl_lwb_max_issued_txg may be larger than lwb_max_txg. It depends
* on the time when the dmu_tx transaction is assigned in
* zil_lwb_write_issue().
*/
mutex_enter(&zilog->zl_lwb_io_lock);
txg = MAX(zilog->zl_lwb_max_issued_txg, txg);
mutex_exit(&zilog->zl_lwb_io_lock);
/*
* We need to use txg_wait_synced() to wait until that txg is synced.
* zil_sync() will guarantee all lwbs up to that txg have been
* written out, flushed, and cleaned.
*/
if (txg != 0)
txg_wait_synced(zilog->zl_dmu_pool, txg);
if (zilog_is_dirty(zilog))
zfs_dbgmsg("zil (%px) is dirty, txg %llu", zilog,
(u_longlong_t)txg);
if (txg < spa_freeze_txg(zilog->zl_spa))
VERIFY(!zilog_is_dirty(zilog));
zilog->zl_get_data = NULL;
/*
* We should have only one lwb left on the list; remove it now.
*/
mutex_enter(&zilog->zl_lock);
lwb = list_remove_head(&zilog->zl_lwb_list);
if (lwb != NULL) {
ASSERT(list_is_empty(&zilog->zl_lwb_list));
ASSERT3S(lwb->lwb_state, ==, LWB_STATE_NEW);
zio_buf_free(lwb->lwb_buf, lwb->lwb_sz);
zil_free_lwb(zilog, lwb);
}
mutex_exit(&zilog->zl_lock);
}
static const char *suspend_tag = "zil suspending";
/*
* Suspend an intent log. While in suspended mode, we still honor
* synchronous semantics, but we rely on txg_wait_synced() to do it.
* On old version pools, we suspend the log briefly when taking a
* snapshot so that it will have an empty intent log.
*
* Long holds are not really intended to be used the way we do here --
* held for such a short time. A concurrent caller of dsl_dataset_long_held()
* could fail. Therefore we take pains to only put a long hold if it is
* actually necessary. Fortunately, it will only be necessary if the
* objset is currently mounted (or the ZVOL equivalent). In that case it
* will already have a long hold, so we are not really making things any worse.
*
* Ideally, we would locate the existing long-holder (i.e. the zfsvfs_t or
* zvol_state_t), and use their mechanism to prevent their hold from being
* dropped (e.g. VFS_HOLD()). However, that would be even more pain for
* very little gain.
*
* if cookiep == NULL, this does both the suspend & resume.
* Otherwise, it returns with the dataset "long held", and the cookie
* should be passed into zil_resume().
*/
int
zil_suspend(const char *osname, void **cookiep)
{
objset_t *os;
zilog_t *zilog;
const zil_header_t *zh;
int error;
error = dmu_objset_hold(osname, suspend_tag, &os);
if (error != 0)
return (error);
zilog = dmu_objset_zil(os);
mutex_enter(&zilog->zl_lock);
zh = zilog->zl_header;
if (zh->zh_flags & ZIL_REPLAY_NEEDED) { /* unplayed log */
mutex_exit(&zilog->zl_lock);
dmu_objset_rele(os, suspend_tag);
return (SET_ERROR(EBUSY));
}
/*
* Don't put a long hold in the cases where we can avoid it. This
* is when there is no cookie so we are doing a suspend & resume
* (i.e. called from zil_vdev_offline()), and there's nothing to do
* for the suspend because it's already suspended, or there's no ZIL.
*/
if (cookiep == NULL && !zilog->zl_suspending &&
(zilog->zl_suspend > 0 || BP_IS_HOLE(&zh->zh_log))) {
mutex_exit(&zilog->zl_lock);
dmu_objset_rele(os, suspend_tag);
return (0);
}
dsl_dataset_long_hold(dmu_objset_ds(os), suspend_tag);
dsl_pool_rele(dmu_objset_pool(os), suspend_tag);
zilog->zl_suspend++;
if (zilog->zl_suspend > 1) {
/*
* Someone else is already suspending it.
* Just wait for them to finish.
*/
while (zilog->zl_suspending)
cv_wait(&zilog->zl_cv_suspend, &zilog->zl_lock);
mutex_exit(&zilog->zl_lock);
if (cookiep == NULL)
zil_resume(os);
else
*cookiep = os;
return (0);
}
/*
* If there is no pointer to an on-disk block, this ZIL must not
* be active (e.g. filesystem not mounted), so there's nothing
* to clean up.
*/
if (BP_IS_HOLE(&zh->zh_log)) {
ASSERT(cookiep != NULL); /* fast path already handled */
*cookiep = os;
mutex_exit(&zilog->zl_lock);
return (0);
}
/*
* The ZIL has work to do. Ensure that the associated encryption
* key will remain mapped while we are committing the log by
* grabbing a reference to it. If the key isn't loaded we have no
* choice but to return an error until the wrapping key is loaded.
*/
if (os->os_encrypted &&
dsl_dataset_create_key_mapping(dmu_objset_ds(os)) != 0) {
zilog->zl_suspend--;
mutex_exit(&zilog->zl_lock);
dsl_dataset_long_rele(dmu_objset_ds(os), suspend_tag);
dsl_dataset_rele(dmu_objset_ds(os), suspend_tag);
return (SET_ERROR(EACCES));
}
zilog->zl_suspending = B_TRUE;
mutex_exit(&zilog->zl_lock);
/*
* We need to use zil_commit_impl to ensure we wait for all
* LWB_STATE_OPENED, _CLOSED and _READY lwbs to be committed
* to disk before proceeding. If we used zil_commit instead, it
* would just call txg_wait_synced(), because zl_suspend is set.
* txg_wait_synced() doesn't wait for these lwb's to be
* LWB_STATE_FLUSH_DONE before returning.
*/
zil_commit_impl(zilog, 0);
/*
* Now that we've ensured all lwb's are LWB_STATE_FLUSH_DONE, we
* use txg_wait_synced() to ensure the data from the zilog has
* migrated to the main pool before calling zil_destroy().
*/
txg_wait_synced(zilog->zl_dmu_pool, 0);
zil_destroy(zilog, B_FALSE);
mutex_enter(&zilog->zl_lock);
zilog->zl_suspending = B_FALSE;
cv_broadcast(&zilog->zl_cv_suspend);
mutex_exit(&zilog->zl_lock);
if (os->os_encrypted)
dsl_dataset_remove_key_mapping(dmu_objset_ds(os));
if (cookiep == NULL)
zil_resume(os);
else
*cookiep = os;
return (0);
}
void
zil_resume(void *cookie)
{
objset_t *os = cookie;
zilog_t *zilog = dmu_objset_zil(os);
mutex_enter(&zilog->zl_lock);
ASSERT(zilog->zl_suspend != 0);
zilog->zl_suspend--;
mutex_exit(&zilog->zl_lock);
dsl_dataset_long_rele(dmu_objset_ds(os), suspend_tag);
dsl_dataset_rele(dmu_objset_ds(os), suspend_tag);
}
typedef struct zil_replay_arg {
zil_replay_func_t *const *zr_replay;
void *zr_arg;
boolean_t zr_byteswap;
char *zr_lr;
} zil_replay_arg_t;
static int
zil_replay_error(zilog_t *zilog, const lr_t *lr, int error)
{
char name[ZFS_MAX_DATASET_NAME_LEN];
zilog->zl_replaying_seq--; /* didn't actually replay this one */
dmu_objset_name(zilog->zl_os, name);
cmn_err(CE_WARN, "ZFS replay transaction error %d, "
"dataset %s, seq 0x%llx, txtype %llu %s\n", error, name,
(u_longlong_t)lr->lrc_seq,
(u_longlong_t)(lr->lrc_txtype & ~TX_CI),
(lr->lrc_txtype & TX_CI) ? "CI" : "");
return (error);
}
static int
zil_replay_log_record(zilog_t *zilog, const lr_t *lr, void *zra,
uint64_t claim_txg)
{
zil_replay_arg_t *zr = zra;
const zil_header_t *zh = zilog->zl_header;
uint64_t reclen = lr->lrc_reclen;
uint64_t txtype = lr->lrc_txtype;
int error = 0;
zilog->zl_replaying_seq = lr->lrc_seq;
if (lr->lrc_seq <= zh->zh_replay_seq) /* already replayed */
return (0);
if (lr->lrc_txg < claim_txg) /* already committed */
return (0);
/* Strip case-insensitive bit, still present in log record */
txtype &= ~TX_CI;
if (txtype == 0 || txtype >= TX_MAX_TYPE)
return (zil_replay_error(zilog, lr, EINVAL));
/*
* If this record type can be logged out of order, the object
* (lr_foid) may no longer exist. That's legitimate, not an error.
*/
if (TX_OOO(txtype)) {
error = dmu_object_info(zilog->zl_os,
LR_FOID_GET_OBJ(((lr_ooo_t *)lr)->lr_foid), NULL);
if (error == ENOENT || error == EEXIST)
return (0);
}
/*
* Make a copy of the data so we can revise and extend it.
*/
memcpy(zr->zr_lr, lr, reclen);
/*
* If this is a TX_WRITE with a blkptr, suck in the data.
*/
if (txtype == TX_WRITE && reclen == sizeof (lr_write_t)) {
error = zil_read_log_data(zilog, (lr_write_t *)lr,
zr->zr_lr + reclen);
if (error != 0)
return (zil_replay_error(zilog, lr, error));
}
/*
* The log block containing this lr may have been byteswapped
* so that we can easily examine common fields like lrc_txtype.
* However, the log is a mix of different record types, and only the
* replay vectors know how to byteswap their records. Therefore, if
* the lr was byteswapped, undo it before invoking the replay vector.
*/
if (zr->zr_byteswap)
byteswap_uint64_array(zr->zr_lr, reclen);
/*
* We must now do two things atomically: replay this log record,
* and update the log header sequence number to reflect the fact that
* we did so. At the end of each replay function the sequence number
* is updated if we are in replay mode.
*/
error = zr->zr_replay[txtype](zr->zr_arg, zr->zr_lr, zr->zr_byteswap);
if (error != 0) {
/*
* The DMU's dnode layer doesn't see removes until the txg
* commits, so a subsequent claim can spuriously fail with
* EEXIST. So if we receive any error we try syncing out
* any removes then retry the transaction. Note that we
* specify B_FALSE for byteswap now, so we don't do it twice.
*/
txg_wait_synced(spa_get_dsl(zilog->zl_spa), 0);
error = zr->zr_replay[txtype](zr->zr_arg, zr->zr_lr, B_FALSE);
if (error != 0)
return (zil_replay_error(zilog, lr, error));
}
return (0);
}
static int
zil_incr_blks(zilog_t *zilog, const blkptr_t *bp, void *arg, uint64_t claim_txg)
{
(void) bp, (void) arg, (void) claim_txg;
zilog->zl_replay_blks++;
return (0);
}
/*
* If this dataset has a non-empty intent log, replay it and destroy it.
* Return B_TRUE if there were any entries to replay.
*/
boolean_t
zil_replay(objset_t *os, void *arg,
zil_replay_func_t *const replay_func[TX_MAX_TYPE])
{
zilog_t *zilog = dmu_objset_zil(os);
const zil_header_t *zh = zilog->zl_header;
zil_replay_arg_t zr;
if ((zh->zh_flags & ZIL_REPLAY_NEEDED) == 0) {
return (zil_destroy(zilog, B_TRUE));
}
zr.zr_replay = replay_func;
zr.zr_arg = arg;
zr.zr_byteswap = BP_SHOULD_BYTESWAP(&zh->zh_log);
zr.zr_lr = vmem_alloc(2 * SPA_MAXBLOCKSIZE, KM_SLEEP);
/*
* Wait for in-progress removes to sync before starting replay.
*/
txg_wait_synced(zilog->zl_dmu_pool, 0);
zilog->zl_replay = B_TRUE;
zilog->zl_replay_time = ddi_get_lbolt();
ASSERT(zilog->zl_replay_blks == 0);
(void) zil_parse(zilog, zil_incr_blks, zil_replay_log_record, &zr,
zh->zh_claim_txg, B_TRUE);
vmem_free(zr.zr_lr, 2 * SPA_MAXBLOCKSIZE);
zil_destroy(zilog, B_FALSE);
txg_wait_synced(zilog->zl_dmu_pool, zilog->zl_destroy_txg);
zilog->zl_replay = B_FALSE;
return (B_TRUE);
}
boolean_t
zil_replaying(zilog_t *zilog, dmu_tx_t *tx)
{
if (zilog->zl_sync == ZFS_SYNC_DISABLED)
return (B_TRUE);
if (zilog->zl_replay) {
dsl_dataset_dirty(dmu_objset_ds(zilog->zl_os), tx);
zilog->zl_replayed_seq[dmu_tx_get_txg(tx) & TXG_MASK] =
zilog->zl_replaying_seq;
return (B_TRUE);
}
return (B_FALSE);
}
int
zil_reset(const char *osname, void *arg)
{
(void) arg;
int error = zil_suspend(osname, NULL);
/* EACCES means crypto key not loaded */
if ((error == EACCES) || (error == EBUSY))
return (SET_ERROR(error));
if (error != 0)
return (SET_ERROR(EEXIST));
return (0);
}
EXPORT_SYMBOL(zil_alloc);
EXPORT_SYMBOL(zil_free);
EXPORT_SYMBOL(zil_open);
EXPORT_SYMBOL(zil_close);
EXPORT_SYMBOL(zil_replay);
EXPORT_SYMBOL(zil_replaying);
EXPORT_SYMBOL(zil_destroy);
EXPORT_SYMBOL(zil_destroy_sync);
EXPORT_SYMBOL(zil_itx_create);
EXPORT_SYMBOL(zil_itx_destroy);
EXPORT_SYMBOL(zil_itx_assign);
EXPORT_SYMBOL(zil_commit);
EXPORT_SYMBOL(zil_claim);
EXPORT_SYMBOL(zil_check_log_chain);
EXPORT_SYMBOL(zil_sync);
EXPORT_SYMBOL(zil_clean);
EXPORT_SYMBOL(zil_suspend);
EXPORT_SYMBOL(zil_resume);
EXPORT_SYMBOL(zil_lwb_add_block);
EXPORT_SYMBOL(zil_bp_tree_add);
EXPORT_SYMBOL(zil_set_sync);
EXPORT_SYMBOL(zil_set_logbias);
EXPORT_SYMBOL(zil_sums_init);
EXPORT_SYMBOL(zil_sums_fini);
EXPORT_SYMBOL(zil_kstat_values_update);
ZFS_MODULE_PARAM(zfs, zfs_, commit_timeout_pct, UINT, ZMOD_RW,
"ZIL block open timeout percentage");
ZFS_MODULE_PARAM(zfs_zil, zil_, min_commit_timeout, U64, ZMOD_RW,
"Minimum delay we care for ZIL block commit");
ZFS_MODULE_PARAM(zfs_zil, zil_, replay_disable, INT, ZMOD_RW,
"Disable intent logging replay");
ZFS_MODULE_PARAM(zfs_zil, zil_, nocacheflush, INT, ZMOD_RW,
"Disable ZIL cache flushes");
ZFS_MODULE_PARAM(zfs_zil, zil_, slog_bulk, U64, ZMOD_RW,
"Limit in bytes slog sync writes per commit");
ZFS_MODULE_PARAM(zfs_zil, zil_, maxblocksize, UINT, ZMOD_RW,
"Limit in bytes of ZIL log block size");
ZFS_MODULE_PARAM(zfs_zil, zil_, maxcopied, UINT, ZMOD_RW,
"Limit in bytes WR_COPIED size");