4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
13 * When distributing Covered Code, include this CDDL HEADER in each
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15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
22 * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
23 * Copyright (c) 2011, 2018 by Delphix. All rights reserved.
24 * Copyright (c) 2014 Integros [integros.com]
25 * Copyright (c) 2018 Datto Inc.
28 /* Portions Copyright 2010 Robert Milkowski */
30 #include <sys/zfs_context.h>
32 #include <sys/spa_impl.h>
38 #include <sys/zil_impl.h>
39 #include <sys/dsl_dataset.h>
40 #include <sys/vdev_impl.h>
41 #include <sys/dmu_tx.h>
42 #include <sys/dsl_pool.h>
43 #include <sys/metaslab.h>
44 #include <sys/trace_zil.h>
48 * The ZFS Intent Log (ZIL) saves "transaction records" (itxs) of system
49 * calls that change the file system. Each itx has enough information to
50 * be able to replay them after a system crash, power loss, or
51 * equivalent failure mode. These are stored in memory until either:
53 * 1. they are committed to the pool by the DMU transaction group
54 * (txg), at which point they can be discarded; or
55 * 2. they are committed to the on-disk ZIL for the dataset being
56 * modified (e.g. due to an fsync, O_DSYNC, or other synchronous
59 * In the event of a crash or power loss, the itxs contained by each
60 * dataset's on-disk ZIL will be replayed when that dataset is first
61 * instantiated (e.g. if the dataset is a normal fileystem, when it is
64 * As hinted at above, there is one ZIL per dataset (both the in-memory
65 * representation, and the on-disk representation). The on-disk format
66 * consists of 3 parts:
68 * - a single, per-dataset, ZIL header; which points to a chain of
69 * - zero or more ZIL blocks; each of which contains
70 * - zero or more ZIL records
72 * A ZIL record holds the information necessary to replay a single
73 * system call transaction. A ZIL block can hold many ZIL records, and
74 * the blocks are chained together, similarly to a singly linked list.
76 * Each ZIL block contains a block pointer (blkptr_t) to the next ZIL
77 * block in the chain, and the ZIL header points to the first block in
80 * Note, there is not a fixed place in the pool to hold these ZIL
81 * blocks; they are dynamically allocated and freed as needed from the
82 * blocks available on the pool, though they can be preferentially
83 * allocated from a dedicated "log" vdev.
87 * This controls the amount of time that a ZIL block (lwb) will remain
88 * "open" when it isn't "full", and it has a thread waiting for it to be
89 * committed to stable storage. Please refer to the zil_commit_waiter()
90 * function (and the comments within it) for more details.
92 int zfs_commit_timeout_pct = 5;
95 * See zil.h for more information about these fields.
97 zil_stats_t zil_stats = {
98 { "zil_commit_count", KSTAT_DATA_UINT64 },
99 { "zil_commit_writer_count", KSTAT_DATA_UINT64 },
100 { "zil_itx_count", KSTAT_DATA_UINT64 },
101 { "zil_itx_indirect_count", KSTAT_DATA_UINT64 },
102 { "zil_itx_indirect_bytes", KSTAT_DATA_UINT64 },
103 { "zil_itx_copied_count", KSTAT_DATA_UINT64 },
104 { "zil_itx_copied_bytes", KSTAT_DATA_UINT64 },
105 { "zil_itx_needcopy_count", KSTAT_DATA_UINT64 },
106 { "zil_itx_needcopy_bytes", KSTAT_DATA_UINT64 },
107 { "zil_itx_metaslab_normal_count", KSTAT_DATA_UINT64 },
108 { "zil_itx_metaslab_normal_bytes", KSTAT_DATA_UINT64 },
109 { "zil_itx_metaslab_slog_count", KSTAT_DATA_UINT64 },
110 { "zil_itx_metaslab_slog_bytes", KSTAT_DATA_UINT64 },
113 static kstat_t *zil_ksp;
116 * Disable intent logging replay. This global ZIL switch affects all pools.
118 int zil_replay_disable = 0;
121 * Disable the DKIOCFLUSHWRITECACHE commands that are normally sent to
122 * the disk(s) by the ZIL after an LWB write has completed. Setting this
123 * will cause ZIL corruption on power loss if a volatile out-of-order
124 * write cache is enabled.
126 int zil_nocacheflush = 0;
129 * Limit SLOG write size per commit executed with synchronous priority.
130 * Any writes above that will be executed with lower (asynchronous) priority
131 * to limit potential SLOG device abuse by single active ZIL writer.
133 unsigned long zil_slog_bulk = 768 * 1024;
135 static kmem_cache_t *zil_lwb_cache;
136 static kmem_cache_t *zil_zcw_cache;
138 static void zil_async_to_sync(zilog_t *zilog, uint64_t foid);
140 #define LWB_EMPTY(lwb) ((BP_GET_LSIZE(&lwb->lwb_blk) - \
141 sizeof (zil_chain_t)) == (lwb->lwb_sz - lwb->lwb_nused))
144 zil_bp_compare(const void *x1, const void *x2)
146 const dva_t *dva1 = &((zil_bp_node_t *)x1)->zn_dva;
147 const dva_t *dva2 = &((zil_bp_node_t *)x2)->zn_dva;
149 int cmp = AVL_CMP(DVA_GET_VDEV(dva1), DVA_GET_VDEV(dva2));
153 return (AVL_CMP(DVA_GET_OFFSET(dva1), DVA_GET_OFFSET(dva2)));
157 zil_bp_tree_init(zilog_t *zilog)
159 avl_create(&zilog->zl_bp_tree, zil_bp_compare,
160 sizeof (zil_bp_node_t), offsetof(zil_bp_node_t, zn_node));
164 zil_bp_tree_fini(zilog_t *zilog)
166 avl_tree_t *t = &zilog->zl_bp_tree;
170 while ((zn = avl_destroy_nodes(t, &cookie)) != NULL)
171 kmem_free(zn, sizeof (zil_bp_node_t));
177 zil_bp_tree_add(zilog_t *zilog, const blkptr_t *bp)
179 avl_tree_t *t = &zilog->zl_bp_tree;
184 if (BP_IS_EMBEDDED(bp))
187 dva = BP_IDENTITY(bp);
189 if (avl_find(t, dva, &where) != NULL)
190 return (SET_ERROR(EEXIST));
192 zn = kmem_alloc(sizeof (zil_bp_node_t), KM_SLEEP);
194 avl_insert(t, zn, where);
199 static zil_header_t *
200 zil_header_in_syncing_context(zilog_t *zilog)
202 return ((zil_header_t *)zilog->zl_header);
206 zil_init_log_chain(zilog_t *zilog, blkptr_t *bp)
208 zio_cksum_t *zc = &bp->blk_cksum;
210 zc->zc_word[ZIL_ZC_GUID_0] = spa_get_random(-1ULL);
211 zc->zc_word[ZIL_ZC_GUID_1] = spa_get_random(-1ULL);
212 zc->zc_word[ZIL_ZC_OBJSET] = dmu_objset_id(zilog->zl_os);
213 zc->zc_word[ZIL_ZC_SEQ] = 1ULL;
217 * Read a log block and make sure it's valid.
220 zil_read_log_block(zilog_t *zilog, boolean_t decrypt, const blkptr_t *bp,
221 blkptr_t *nbp, void *dst, char **end)
223 enum zio_flag zio_flags = ZIO_FLAG_CANFAIL;
224 arc_flags_t aflags = ARC_FLAG_WAIT;
225 arc_buf_t *abuf = NULL;
229 if (zilog->zl_header->zh_claim_txg == 0)
230 zio_flags |= ZIO_FLAG_SPECULATIVE | ZIO_FLAG_SCRUB;
232 if (!(zilog->zl_header->zh_flags & ZIL_CLAIM_LR_SEQ_VALID))
233 zio_flags |= ZIO_FLAG_SPECULATIVE;
236 zio_flags |= ZIO_FLAG_RAW;
238 SET_BOOKMARK(&zb, bp->blk_cksum.zc_word[ZIL_ZC_OBJSET],
239 ZB_ZIL_OBJECT, ZB_ZIL_LEVEL, bp->blk_cksum.zc_word[ZIL_ZC_SEQ]);
241 error = arc_read(NULL, zilog->zl_spa, bp, arc_getbuf_func,
242 &abuf, ZIO_PRIORITY_SYNC_READ, zio_flags, &aflags, &zb);
245 zio_cksum_t cksum = bp->blk_cksum;
248 * Validate the checksummed log block.
250 * Sequence numbers should be... sequential. The checksum
251 * verifier for the next block should be bp's checksum plus 1.
253 * Also check the log chain linkage and size used.
255 cksum.zc_word[ZIL_ZC_SEQ]++;
257 if (BP_GET_CHECKSUM(bp) == ZIO_CHECKSUM_ZILOG2) {
258 zil_chain_t *zilc = abuf->b_data;
259 char *lr = (char *)(zilc + 1);
260 uint64_t len = zilc->zc_nused - sizeof (zil_chain_t);
262 if (bcmp(&cksum, &zilc->zc_next_blk.blk_cksum,
263 sizeof (cksum)) || BP_IS_HOLE(&zilc->zc_next_blk)) {
264 error = SET_ERROR(ECKSUM);
266 ASSERT3U(len, <=, SPA_OLD_MAXBLOCKSIZE);
268 *end = (char *)dst + len;
269 *nbp = zilc->zc_next_blk;
272 char *lr = abuf->b_data;
273 uint64_t size = BP_GET_LSIZE(bp);
274 zil_chain_t *zilc = (zil_chain_t *)(lr + size) - 1;
276 if (bcmp(&cksum, &zilc->zc_next_blk.blk_cksum,
277 sizeof (cksum)) || BP_IS_HOLE(&zilc->zc_next_blk) ||
278 (zilc->zc_nused > (size - sizeof (*zilc)))) {
279 error = SET_ERROR(ECKSUM);
281 ASSERT3U(zilc->zc_nused, <=,
282 SPA_OLD_MAXBLOCKSIZE);
283 bcopy(lr, dst, zilc->zc_nused);
284 *end = (char *)dst + zilc->zc_nused;
285 *nbp = zilc->zc_next_blk;
289 arc_buf_destroy(abuf, &abuf);
296 * Read a TX_WRITE log data block.
299 zil_read_log_data(zilog_t *zilog, const lr_write_t *lr, void *wbuf)
301 enum zio_flag zio_flags = ZIO_FLAG_CANFAIL;
302 const blkptr_t *bp = &lr->lr_blkptr;
303 arc_flags_t aflags = ARC_FLAG_WAIT;
304 arc_buf_t *abuf = NULL;
308 if (BP_IS_HOLE(bp)) {
310 bzero(wbuf, MAX(BP_GET_LSIZE(bp), lr->lr_length));
314 if (zilog->zl_header->zh_claim_txg == 0)
315 zio_flags |= ZIO_FLAG_SPECULATIVE | ZIO_FLAG_SCRUB;
318 * If we are not using the resulting data, we are just checking that
319 * it hasn't been corrupted so we don't need to waste CPU time
320 * decompressing and decrypting it.
323 zio_flags |= ZIO_FLAG_RAW;
325 SET_BOOKMARK(&zb, dmu_objset_id(zilog->zl_os), lr->lr_foid,
326 ZB_ZIL_LEVEL, lr->lr_offset / BP_GET_LSIZE(bp));
328 error = arc_read(NULL, zilog->zl_spa, bp, arc_getbuf_func, &abuf,
329 ZIO_PRIORITY_SYNC_READ, zio_flags, &aflags, &zb);
333 bcopy(abuf->b_data, wbuf, arc_buf_size(abuf));
334 arc_buf_destroy(abuf, &abuf);
341 * Parse the intent log, and call parse_func for each valid record within.
344 zil_parse(zilog_t *zilog, zil_parse_blk_func_t *parse_blk_func,
345 zil_parse_lr_func_t *parse_lr_func, void *arg, uint64_t txg,
348 const zil_header_t *zh = zilog->zl_header;
349 boolean_t claimed = !!zh->zh_claim_txg;
350 uint64_t claim_blk_seq = claimed ? zh->zh_claim_blk_seq : UINT64_MAX;
351 uint64_t claim_lr_seq = claimed ? zh->zh_claim_lr_seq : UINT64_MAX;
352 uint64_t max_blk_seq = 0;
353 uint64_t max_lr_seq = 0;
354 uint64_t blk_count = 0;
355 uint64_t lr_count = 0;
356 blkptr_t blk, next_blk;
360 bzero(&next_blk, sizeof (blkptr_t));
363 * Old logs didn't record the maximum zh_claim_lr_seq.
365 if (!(zh->zh_flags & ZIL_CLAIM_LR_SEQ_VALID))
366 claim_lr_seq = UINT64_MAX;
369 * Starting at the block pointed to by zh_log we read the log chain.
370 * For each block in the chain we strongly check that block to
371 * ensure its validity. We stop when an invalid block is found.
372 * For each block pointer in the chain we call parse_blk_func().
373 * For each record in each valid block we call parse_lr_func().
374 * If the log has been claimed, stop if we encounter a sequence
375 * number greater than the highest claimed sequence number.
377 lrbuf = zio_buf_alloc(SPA_OLD_MAXBLOCKSIZE);
378 zil_bp_tree_init(zilog);
380 for (blk = zh->zh_log; !BP_IS_HOLE(&blk); blk = next_blk) {
381 uint64_t blk_seq = blk.blk_cksum.zc_word[ZIL_ZC_SEQ];
385 if (blk_seq > claim_blk_seq)
388 error = parse_blk_func(zilog, &blk, arg, txg);
391 ASSERT3U(max_blk_seq, <, blk_seq);
392 max_blk_seq = blk_seq;
395 if (max_lr_seq == claim_lr_seq && max_blk_seq == claim_blk_seq)
398 error = zil_read_log_block(zilog, decrypt, &blk, &next_blk,
403 for (lrp = lrbuf; lrp < end; lrp += reclen) {
404 lr_t *lr = (lr_t *)lrp;
405 reclen = lr->lrc_reclen;
406 ASSERT3U(reclen, >=, sizeof (lr_t));
407 if (lr->lrc_seq > claim_lr_seq)
410 error = parse_lr_func(zilog, lr, arg, txg);
413 ASSERT3U(max_lr_seq, <, lr->lrc_seq);
414 max_lr_seq = lr->lrc_seq;
419 zilog->zl_parse_error = error;
420 zilog->zl_parse_blk_seq = max_blk_seq;
421 zilog->zl_parse_lr_seq = max_lr_seq;
422 zilog->zl_parse_blk_count = blk_count;
423 zilog->zl_parse_lr_count = lr_count;
425 ASSERT(!claimed || !(zh->zh_flags & ZIL_CLAIM_LR_SEQ_VALID) ||
426 (max_blk_seq == claim_blk_seq && max_lr_seq == claim_lr_seq) ||
427 (decrypt && error == EIO));
429 zil_bp_tree_fini(zilog);
430 zio_buf_free(lrbuf, SPA_OLD_MAXBLOCKSIZE);
437 zil_clear_log_block(zilog_t *zilog, blkptr_t *bp, void *tx, uint64_t first_txg)
439 ASSERT(!BP_IS_HOLE(bp));
442 * As we call this function from the context of a rewind to a
443 * checkpoint, each ZIL block whose txg is later than the txg
444 * that we rewind to is invalid. Thus, we return -1 so
445 * zil_parse() doesn't attempt to read it.
447 if (bp->blk_birth >= first_txg)
450 if (zil_bp_tree_add(zilog, bp) != 0)
453 zio_free(zilog->zl_spa, first_txg, bp);
459 zil_noop_log_record(zilog_t *zilog, lr_t *lrc, void *tx, uint64_t first_txg)
465 zil_claim_log_block(zilog_t *zilog, blkptr_t *bp, void *tx, uint64_t first_txg)
468 * Claim log block if not already committed and not already claimed.
469 * If tx == NULL, just verify that the block is claimable.
471 if (BP_IS_HOLE(bp) || bp->blk_birth < first_txg ||
472 zil_bp_tree_add(zilog, bp) != 0)
475 return (zio_wait(zio_claim(NULL, zilog->zl_spa,
476 tx == NULL ? 0 : first_txg, bp, spa_claim_notify, NULL,
477 ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE | ZIO_FLAG_SCRUB)));
481 zil_claim_log_record(zilog_t *zilog, lr_t *lrc, void *tx, uint64_t first_txg)
483 lr_write_t *lr = (lr_write_t *)lrc;
486 if (lrc->lrc_txtype != TX_WRITE)
490 * If the block is not readable, don't claim it. This can happen
491 * in normal operation when a log block is written to disk before
492 * some of the dmu_sync() blocks it points to. In this case, the
493 * transaction cannot have been committed to anyone (we would have
494 * waited for all writes to be stable first), so it is semantically
495 * correct to declare this the end of the log.
497 if (lr->lr_blkptr.blk_birth >= first_txg) {
498 error = zil_read_log_data(zilog, lr, NULL);
503 return (zil_claim_log_block(zilog, &lr->lr_blkptr, tx, first_txg));
508 zil_free_log_block(zilog_t *zilog, blkptr_t *bp, void *tx, uint64_t claim_txg)
510 zio_free(zilog->zl_spa, dmu_tx_get_txg(tx), bp);
516 zil_free_log_record(zilog_t *zilog, lr_t *lrc, void *tx, uint64_t claim_txg)
518 lr_write_t *lr = (lr_write_t *)lrc;
519 blkptr_t *bp = &lr->lr_blkptr;
522 * If we previously claimed it, we need to free it.
524 if (claim_txg != 0 && lrc->lrc_txtype == TX_WRITE &&
525 bp->blk_birth >= claim_txg && zil_bp_tree_add(zilog, bp) == 0 &&
527 zio_free(zilog->zl_spa, dmu_tx_get_txg(tx), bp);
533 zil_lwb_vdev_compare(const void *x1, const void *x2)
535 const uint64_t v1 = ((zil_vdev_node_t *)x1)->zv_vdev;
536 const uint64_t v2 = ((zil_vdev_node_t *)x2)->zv_vdev;
538 return (AVL_CMP(v1, v2));
542 zil_alloc_lwb(zilog_t *zilog, blkptr_t *bp, boolean_t slog, uint64_t txg,
547 lwb = kmem_cache_alloc(zil_lwb_cache, KM_SLEEP);
548 lwb->lwb_zilog = zilog;
550 lwb->lwb_fastwrite = fastwrite;
551 lwb->lwb_slog = slog;
552 lwb->lwb_state = LWB_STATE_CLOSED;
553 lwb->lwb_buf = zio_buf_alloc(BP_GET_LSIZE(bp));
554 lwb->lwb_max_txg = txg;
555 lwb->lwb_write_zio = NULL;
556 lwb->lwb_root_zio = NULL;
558 lwb->lwb_issued_timestamp = 0;
559 if (BP_GET_CHECKSUM(bp) == ZIO_CHECKSUM_ZILOG2) {
560 lwb->lwb_nused = sizeof (zil_chain_t);
561 lwb->lwb_sz = BP_GET_LSIZE(bp);
564 lwb->lwb_sz = BP_GET_LSIZE(bp) - sizeof (zil_chain_t);
567 mutex_enter(&zilog->zl_lock);
568 list_insert_tail(&zilog->zl_lwb_list, lwb);
569 mutex_exit(&zilog->zl_lock);
571 ASSERT(!MUTEX_HELD(&lwb->lwb_vdev_lock));
572 ASSERT(avl_is_empty(&lwb->lwb_vdev_tree));
573 VERIFY(list_is_empty(&lwb->lwb_waiters));
574 VERIFY(list_is_empty(&lwb->lwb_itxs));
580 zil_free_lwb(zilog_t *zilog, lwb_t *lwb)
582 ASSERT(MUTEX_HELD(&zilog->zl_lock));
583 ASSERT(!MUTEX_HELD(&lwb->lwb_vdev_lock));
584 VERIFY(list_is_empty(&lwb->lwb_waiters));
585 VERIFY(list_is_empty(&lwb->lwb_itxs));
586 ASSERT(avl_is_empty(&lwb->lwb_vdev_tree));
587 ASSERT3P(lwb->lwb_write_zio, ==, NULL);
588 ASSERT3P(lwb->lwb_root_zio, ==, NULL);
589 ASSERT3U(lwb->lwb_max_txg, <=, spa_syncing_txg(zilog->zl_spa));
590 ASSERT(lwb->lwb_state == LWB_STATE_CLOSED ||
591 lwb->lwb_state == LWB_STATE_FLUSH_DONE);
594 * Clear the zilog's field to indicate this lwb is no longer
595 * valid, and prevent use-after-free errors.
597 if (zilog->zl_last_lwb_opened == lwb)
598 zilog->zl_last_lwb_opened = NULL;
600 kmem_cache_free(zil_lwb_cache, lwb);
604 * Called when we create in-memory log transactions so that we know
605 * to cleanup the itxs at the end of spa_sync().
608 zilog_dirty(zilog_t *zilog, uint64_t txg)
610 dsl_pool_t *dp = zilog->zl_dmu_pool;
611 dsl_dataset_t *ds = dmu_objset_ds(zilog->zl_os);
613 ASSERT(spa_writeable(zilog->zl_spa));
615 if (ds->ds_is_snapshot)
616 panic("dirtying snapshot!");
618 if (txg_list_add(&dp->dp_dirty_zilogs, zilog, txg)) {
619 /* up the hold count until we can be written out */
620 dmu_buf_add_ref(ds->ds_dbuf, zilog);
622 zilog->zl_dirty_max_txg = MAX(txg, zilog->zl_dirty_max_txg);
627 * Determine if the zil is dirty in the specified txg. Callers wanting to
628 * ensure that the dirty state does not change must hold the itxg_lock for
629 * the specified txg. Holding the lock will ensure that the zil cannot be
630 * dirtied (zil_itx_assign) or cleaned (zil_clean) while we check its current
634 zilog_is_dirty_in_txg(zilog_t *zilog, uint64_t txg)
636 dsl_pool_t *dp = zilog->zl_dmu_pool;
638 if (txg_list_member(&dp->dp_dirty_zilogs, zilog, txg & TXG_MASK))
644 * Determine if the zil is dirty. The zil is considered dirty if it has
645 * any pending itx records that have not been cleaned by zil_clean().
648 zilog_is_dirty(zilog_t *zilog)
650 dsl_pool_t *dp = zilog->zl_dmu_pool;
652 for (int t = 0; t < TXG_SIZE; t++) {
653 if (txg_list_member(&dp->dp_dirty_zilogs, zilog, t))
660 * Create an on-disk intent log.
663 zil_create(zilog_t *zilog)
665 const zil_header_t *zh = zilog->zl_header;
671 boolean_t fastwrite = FALSE;
672 boolean_t slog = FALSE;
675 * Wait for any previous destroy to complete.
677 txg_wait_synced(zilog->zl_dmu_pool, zilog->zl_destroy_txg);
679 ASSERT(zh->zh_claim_txg == 0);
680 ASSERT(zh->zh_replay_seq == 0);
685 * Allocate an initial log block if:
686 * - there isn't one already
687 * - the existing block is the wrong endianness
689 if (BP_IS_HOLE(&blk) || BP_SHOULD_BYTESWAP(&blk)) {
690 tx = dmu_tx_create(zilog->zl_os);
691 VERIFY0(dmu_tx_assign(tx, TXG_WAIT));
692 dsl_dataset_dirty(dmu_objset_ds(zilog->zl_os), tx);
693 txg = dmu_tx_get_txg(tx);
695 if (!BP_IS_HOLE(&blk)) {
696 zio_free(zilog->zl_spa, txg, &blk);
700 error = zio_alloc_zil(zilog->zl_spa, zilog->zl_os, txg, &blk,
701 ZIL_MIN_BLKSZ, &slog);
705 zil_init_log_chain(zilog, &blk);
709 * Allocate a log write block (lwb) for the first log block.
712 lwb = zil_alloc_lwb(zilog, &blk, slog, txg, fastwrite);
715 * If we just allocated the first log block, commit our transaction
716 * and wait for zil_sync() to stuff the block pointer into zh_log.
717 * (zh is part of the MOS, so we cannot modify it in open context.)
721 txg_wait_synced(zilog->zl_dmu_pool, txg);
724 ASSERT(error != 0 || bcmp(&blk, &zh->zh_log, sizeof (blk)) == 0);
725 IMPLY(error == 0, lwb != NULL);
731 * In one tx, free all log blocks and clear the log header. If keep_first
732 * is set, then we're replaying a log with no content. We want to keep the
733 * first block, however, so that the first synchronous transaction doesn't
734 * require a txg_wait_synced() in zil_create(). We don't need to
735 * txg_wait_synced() here either when keep_first is set, because both
736 * zil_create() and zil_destroy() will wait for any in-progress destroys
740 zil_destroy(zilog_t *zilog, boolean_t keep_first)
742 const zil_header_t *zh = zilog->zl_header;
748 * Wait for any previous destroy to complete.
750 txg_wait_synced(zilog->zl_dmu_pool, zilog->zl_destroy_txg);
752 zilog->zl_old_header = *zh; /* debugging aid */
754 if (BP_IS_HOLE(&zh->zh_log))
757 tx = dmu_tx_create(zilog->zl_os);
758 VERIFY0(dmu_tx_assign(tx, TXG_WAIT));
759 dsl_dataset_dirty(dmu_objset_ds(zilog->zl_os), tx);
760 txg = dmu_tx_get_txg(tx);
762 mutex_enter(&zilog->zl_lock);
764 ASSERT3U(zilog->zl_destroy_txg, <, txg);
765 zilog->zl_destroy_txg = txg;
766 zilog->zl_keep_first = keep_first;
768 if (!list_is_empty(&zilog->zl_lwb_list)) {
769 ASSERT(zh->zh_claim_txg == 0);
771 while ((lwb = list_head(&zilog->zl_lwb_list)) != NULL) {
772 if (lwb->lwb_fastwrite)
773 metaslab_fastwrite_unmark(zilog->zl_spa,
776 list_remove(&zilog->zl_lwb_list, lwb);
777 if (lwb->lwb_buf != NULL)
778 zio_buf_free(lwb->lwb_buf, lwb->lwb_sz);
779 zio_free(zilog->zl_spa, txg, &lwb->lwb_blk);
780 zil_free_lwb(zilog, lwb);
782 } else if (!keep_first) {
783 zil_destroy_sync(zilog, tx);
785 mutex_exit(&zilog->zl_lock);
791 zil_destroy_sync(zilog_t *zilog, dmu_tx_t *tx)
793 ASSERT(list_is_empty(&zilog->zl_lwb_list));
794 (void) zil_parse(zilog, zil_free_log_block,
795 zil_free_log_record, tx, zilog->zl_header->zh_claim_txg, B_FALSE);
799 zil_claim(dsl_pool_t *dp, dsl_dataset_t *ds, void *txarg)
801 dmu_tx_t *tx = txarg;
808 error = dmu_objset_own_obj(dp, ds->ds_object,
809 DMU_OST_ANY, B_FALSE, B_FALSE, FTAG, &os);
812 * EBUSY indicates that the objset is inconsistent, in which
813 * case it can not have a ZIL.
815 if (error != EBUSY) {
816 cmn_err(CE_WARN, "can't open objset for %llu, error %u",
817 (unsigned long long)ds->ds_object, error);
823 zilog = dmu_objset_zil(os);
824 zh = zil_header_in_syncing_context(zilog);
825 ASSERT3U(tx->tx_txg, ==, spa_first_txg(zilog->zl_spa));
826 first_txg = spa_min_claim_txg(zilog->zl_spa);
829 * If the spa_log_state is not set to be cleared, check whether
830 * the current uberblock is a checkpoint one and if the current
831 * header has been claimed before moving on.
833 * If the current uberblock is a checkpointed uberblock then
834 * one of the following scenarios took place:
836 * 1] We are currently rewinding to the checkpoint of the pool.
837 * 2] We crashed in the middle of a checkpoint rewind but we
838 * did manage to write the checkpointed uberblock to the
839 * vdev labels, so when we tried to import the pool again
840 * the checkpointed uberblock was selected from the import
843 * In both cases we want to zero out all the ZIL blocks, except
844 * the ones that have been claimed at the time of the checkpoint
845 * (their zh_claim_txg != 0). The reason is that these blocks
846 * may be corrupted since we may have reused their locations on
847 * disk after we took the checkpoint.
849 * We could try to set spa_log_state to SPA_LOG_CLEAR earlier
850 * when we first figure out whether the current uberblock is
851 * checkpointed or not. Unfortunately, that would discard all
852 * the logs, including the ones that are claimed, and we would
855 if (spa_get_log_state(zilog->zl_spa) == SPA_LOG_CLEAR ||
856 (zilog->zl_spa->spa_uberblock.ub_checkpoint_txg != 0 &&
857 zh->zh_claim_txg == 0)) {
858 if (!BP_IS_HOLE(&zh->zh_log)) {
859 (void) zil_parse(zilog, zil_clear_log_block,
860 zil_noop_log_record, tx, first_txg, B_FALSE);
862 BP_ZERO(&zh->zh_log);
863 if (os->os_encrypted)
864 os->os_next_write_raw[tx->tx_txg & TXG_MASK] = B_TRUE;
865 dsl_dataset_dirty(dmu_objset_ds(os), tx);
866 dmu_objset_disown(os, B_FALSE, FTAG);
871 * If we are not rewinding and opening the pool normally, then
872 * the min_claim_txg should be equal to the first txg of the pool.
874 ASSERT3U(first_txg, ==, spa_first_txg(zilog->zl_spa));
877 * Claim all log blocks if we haven't already done so, and remember
878 * the highest claimed sequence number. This ensures that if we can
879 * read only part of the log now (e.g. due to a missing device),
880 * but we can read the entire log later, we will not try to replay
881 * or destroy beyond the last block we successfully claimed.
883 ASSERT3U(zh->zh_claim_txg, <=, first_txg);
884 if (zh->zh_claim_txg == 0 && !BP_IS_HOLE(&zh->zh_log)) {
885 (void) zil_parse(zilog, zil_claim_log_block,
886 zil_claim_log_record, tx, first_txg, B_FALSE);
887 zh->zh_claim_txg = first_txg;
888 zh->zh_claim_blk_seq = zilog->zl_parse_blk_seq;
889 zh->zh_claim_lr_seq = zilog->zl_parse_lr_seq;
890 if (zilog->zl_parse_lr_count || zilog->zl_parse_blk_count > 1)
891 zh->zh_flags |= ZIL_REPLAY_NEEDED;
892 zh->zh_flags |= ZIL_CLAIM_LR_SEQ_VALID;
893 if (os->os_encrypted)
894 os->os_next_write_raw[tx->tx_txg & TXG_MASK] = B_TRUE;
895 dsl_dataset_dirty(dmu_objset_ds(os), tx);
898 ASSERT3U(first_txg, ==, (spa_last_synced_txg(zilog->zl_spa) + 1));
899 dmu_objset_disown(os, B_FALSE, FTAG);
904 * Check the log by walking the log chain.
905 * Checksum errors are ok as they indicate the end of the chain.
906 * Any other error (no device or read failure) returns an error.
910 zil_check_log_chain(dsl_pool_t *dp, dsl_dataset_t *ds, void *tx)
919 error = dmu_objset_from_ds(ds, &os);
921 cmn_err(CE_WARN, "can't open objset %llu, error %d",
922 (unsigned long long)ds->ds_object, error);
926 zilog = dmu_objset_zil(os);
927 bp = (blkptr_t *)&zilog->zl_header->zh_log;
929 if (!BP_IS_HOLE(bp)) {
931 boolean_t valid = B_TRUE;
934 * Check the first block and determine if it's on a log device
935 * which may have been removed or faulted prior to loading this
936 * pool. If so, there's no point in checking the rest of the
937 * log as its content should have already been synced to the
940 spa_config_enter(os->os_spa, SCL_STATE, FTAG, RW_READER);
941 vd = vdev_lookup_top(os->os_spa, DVA_GET_VDEV(&bp->blk_dva[0]));
942 if (vd->vdev_islog && vdev_is_dead(vd))
943 valid = vdev_log_state_valid(vd);
944 spa_config_exit(os->os_spa, SCL_STATE, FTAG);
950 * Check whether the current uberblock is checkpointed (e.g.
951 * we are rewinding) and whether the current header has been
952 * claimed or not. If it hasn't then skip verifying it. We
953 * do this because its ZIL blocks may be part of the pool's
954 * state before the rewind, which is no longer valid.
956 zil_header_t *zh = zil_header_in_syncing_context(zilog);
957 if (zilog->zl_spa->spa_uberblock.ub_checkpoint_txg != 0 &&
958 zh->zh_claim_txg == 0)
963 * Because tx == NULL, zil_claim_log_block() will not actually claim
964 * any blocks, but just determine whether it is possible to do so.
965 * In addition to checking the log chain, zil_claim_log_block()
966 * will invoke zio_claim() with a done func of spa_claim_notify(),
967 * which will update spa_max_claim_txg. See spa_load() for details.
969 error = zil_parse(zilog, zil_claim_log_block, zil_claim_log_record, tx,
970 zilog->zl_header->zh_claim_txg ? -1ULL :
971 spa_min_claim_txg(os->os_spa), B_FALSE);
973 return ((error == ECKSUM || error == ENOENT) ? 0 : error);
977 * When an itx is "skipped", this function is used to properly mark the
978 * waiter as "done, and signal any thread(s) waiting on it. An itx can
979 * be skipped (and not committed to an lwb) for a variety of reasons,
980 * one of them being that the itx was committed via spa_sync(), prior to
981 * it being committed to an lwb; this can happen if a thread calling
982 * zil_commit() is racing with spa_sync().
985 zil_commit_waiter_skip(zil_commit_waiter_t *zcw)
987 mutex_enter(&zcw->zcw_lock);
988 ASSERT3B(zcw->zcw_done, ==, B_FALSE);
989 zcw->zcw_done = B_TRUE;
990 cv_broadcast(&zcw->zcw_cv);
991 mutex_exit(&zcw->zcw_lock);
995 * This function is used when the given waiter is to be linked into an
996 * lwb's "lwb_waiter" list; i.e. when the itx is committed to the lwb.
997 * At this point, the waiter will no longer be referenced by the itx,
998 * and instead, will be referenced by the lwb.
1001 zil_commit_waiter_link_lwb(zil_commit_waiter_t *zcw, lwb_t *lwb)
1004 * The lwb_waiters field of the lwb is protected by the zilog's
1005 * zl_lock, thus it must be held when calling this function.
1007 ASSERT(MUTEX_HELD(&lwb->lwb_zilog->zl_lock));
1009 mutex_enter(&zcw->zcw_lock);
1010 ASSERT(!list_link_active(&zcw->zcw_node));
1011 ASSERT3P(zcw->zcw_lwb, ==, NULL);
1012 ASSERT3P(lwb, !=, NULL);
1013 ASSERT(lwb->lwb_state == LWB_STATE_OPENED ||
1014 lwb->lwb_state == LWB_STATE_ISSUED ||
1015 lwb->lwb_state == LWB_STATE_WRITE_DONE);
1017 list_insert_tail(&lwb->lwb_waiters, zcw);
1019 mutex_exit(&zcw->zcw_lock);
1023 * This function is used when zio_alloc_zil() fails to allocate a ZIL
1024 * block, and the given waiter must be linked to the "nolwb waiters"
1025 * list inside of zil_process_commit_list().
1028 zil_commit_waiter_link_nolwb(zil_commit_waiter_t *zcw, list_t *nolwb)
1030 mutex_enter(&zcw->zcw_lock);
1031 ASSERT(!list_link_active(&zcw->zcw_node));
1032 ASSERT3P(zcw->zcw_lwb, ==, NULL);
1033 list_insert_tail(nolwb, zcw);
1034 mutex_exit(&zcw->zcw_lock);
1038 zil_lwb_add_block(lwb_t *lwb, const blkptr_t *bp)
1040 avl_tree_t *t = &lwb->lwb_vdev_tree;
1042 zil_vdev_node_t *zv, zvsearch;
1043 int ndvas = BP_GET_NDVAS(bp);
1046 if (zil_nocacheflush)
1049 mutex_enter(&lwb->lwb_vdev_lock);
1050 for (i = 0; i < ndvas; i++) {
1051 zvsearch.zv_vdev = DVA_GET_VDEV(&bp->blk_dva[i]);
1052 if (avl_find(t, &zvsearch, &where) == NULL) {
1053 zv = kmem_alloc(sizeof (*zv), KM_SLEEP);
1054 zv->zv_vdev = zvsearch.zv_vdev;
1055 avl_insert(t, zv, where);
1058 mutex_exit(&lwb->lwb_vdev_lock);
1062 zil_lwb_flush_defer(lwb_t *lwb, lwb_t *nlwb)
1064 avl_tree_t *src = &lwb->lwb_vdev_tree;
1065 avl_tree_t *dst = &nlwb->lwb_vdev_tree;
1066 void *cookie = NULL;
1067 zil_vdev_node_t *zv;
1069 ASSERT3S(lwb->lwb_state, ==, LWB_STATE_WRITE_DONE);
1070 ASSERT3S(nlwb->lwb_state, !=, LWB_STATE_WRITE_DONE);
1071 ASSERT3S(nlwb->lwb_state, !=, LWB_STATE_FLUSH_DONE);
1074 * While 'lwb' is at a point in its lifetime where lwb_vdev_tree does
1075 * not need the protection of lwb_vdev_lock (it will only be modified
1076 * while holding zilog->zl_lock) as its writes and those of its
1077 * children have all completed. The younger 'nlwb' may be waiting on
1078 * future writes to additional vdevs.
1080 mutex_enter(&nlwb->lwb_vdev_lock);
1082 * Tear down the 'lwb' vdev tree, ensuring that entries which do not
1083 * exist in 'nlwb' are moved to it, freeing any would-be duplicates.
1085 while ((zv = avl_destroy_nodes(src, &cookie)) != NULL) {
1088 if (avl_find(dst, zv, &where) == NULL) {
1089 avl_insert(dst, zv, where);
1091 kmem_free(zv, sizeof (*zv));
1094 mutex_exit(&nlwb->lwb_vdev_lock);
1098 zil_lwb_add_txg(lwb_t *lwb, uint64_t txg)
1100 lwb->lwb_max_txg = MAX(lwb->lwb_max_txg, txg);
1104 * This function is a called after all vdevs associated with a given lwb
1105 * write have completed their DKIOCFLUSHWRITECACHE command; or as soon
1106 * as the lwb write completes, if "zil_nocacheflush" is set. Further,
1107 * all "previous" lwb's will have completed before this function is
1108 * called; i.e. this function is called for all previous lwbs before
1109 * it's called for "this" lwb (enforced via zio the dependencies
1110 * configured in zil_lwb_set_zio_dependency()).
1112 * The intention is for this function to be called as soon as the
1113 * contents of an lwb are considered "stable" on disk, and will survive
1114 * any sudden loss of power. At this point, any threads waiting for the
1115 * lwb to reach this state are signalled, and the "waiter" structures
1116 * are marked "done".
1119 zil_lwb_flush_vdevs_done(zio_t *zio)
1121 lwb_t *lwb = zio->io_private;
1122 zilog_t *zilog = lwb->lwb_zilog;
1123 dmu_tx_t *tx = lwb->lwb_tx;
1124 zil_commit_waiter_t *zcw;
1127 spa_config_exit(zilog->zl_spa, SCL_STATE, lwb);
1129 zio_buf_free(lwb->lwb_buf, lwb->lwb_sz);
1131 mutex_enter(&zilog->zl_lock);
1134 * Ensure the lwb buffer pointer is cleared before releasing the
1135 * txg. If we have had an allocation failure and the txg is
1136 * waiting to sync then we want zil_sync() to remove the lwb so
1137 * that it's not picked up as the next new one in
1138 * zil_process_commit_list(). zil_sync() will only remove the
1139 * lwb if lwb_buf is null.
1141 lwb->lwb_buf = NULL;
1144 ASSERT3U(lwb->lwb_issued_timestamp, >, 0);
1145 zilog->zl_last_lwb_latency = gethrtime() - lwb->lwb_issued_timestamp;
1147 lwb->lwb_root_zio = NULL;
1149 ASSERT3S(lwb->lwb_state, ==, LWB_STATE_WRITE_DONE);
1150 lwb->lwb_state = LWB_STATE_FLUSH_DONE;
1152 if (zilog->zl_last_lwb_opened == lwb) {
1154 * Remember the highest committed log sequence number
1155 * for ztest. We only update this value when all the log
1156 * writes succeeded, because ztest wants to ASSERT that
1157 * it got the whole log chain.
1159 zilog->zl_commit_lr_seq = zilog->zl_lr_seq;
1162 while ((itx = list_head(&lwb->lwb_itxs)) != NULL) {
1163 list_remove(&lwb->lwb_itxs, itx);
1164 zil_itx_destroy(itx);
1167 while ((zcw = list_head(&lwb->lwb_waiters)) != NULL) {
1168 mutex_enter(&zcw->zcw_lock);
1170 ASSERT(list_link_active(&zcw->zcw_node));
1171 list_remove(&lwb->lwb_waiters, zcw);
1173 ASSERT3P(zcw->zcw_lwb, ==, lwb);
1174 zcw->zcw_lwb = NULL;
1176 zcw->zcw_zio_error = zio->io_error;
1178 ASSERT3B(zcw->zcw_done, ==, B_FALSE);
1179 zcw->zcw_done = B_TRUE;
1180 cv_broadcast(&zcw->zcw_cv);
1182 mutex_exit(&zcw->zcw_lock);
1185 mutex_exit(&zilog->zl_lock);
1188 * Now that we've written this log block, we have a stable pointer
1189 * to the next block in the chain, so it's OK to let the txg in
1190 * which we allocated the next block sync.
1196 * This is called when an lwb's write zio completes. The callback's
1197 * purpose is to issue the DKIOCFLUSHWRITECACHE commands for the vdevs
1198 * in the lwb's lwb_vdev_tree. The tree will contain the vdevs involved
1199 * in writing out this specific lwb's data, and in the case that cache
1200 * flushes have been deferred, vdevs involved in writing the data for
1201 * previous lwbs. The writes corresponding to all the vdevs in the
1202 * lwb_vdev_tree will have completed by the time this is called, due to
1203 * the zio dependencies configured in zil_lwb_set_zio_dependency(),
1204 * which takes deferred flushes into account. The lwb will be "done"
1205 * once zil_lwb_flush_vdevs_done() is called, which occurs in the zio
1206 * completion callback for the lwb's root zio.
1209 zil_lwb_write_done(zio_t *zio)
1211 lwb_t *lwb = zio->io_private;
1212 spa_t *spa = zio->io_spa;
1213 zilog_t *zilog = lwb->lwb_zilog;
1214 avl_tree_t *t = &lwb->lwb_vdev_tree;
1215 void *cookie = NULL;
1216 zil_vdev_node_t *zv;
1219 ASSERT3S(spa_config_held(spa, SCL_STATE, RW_READER), !=, 0);
1221 ASSERT(BP_GET_COMPRESS(zio->io_bp) == ZIO_COMPRESS_OFF);
1222 ASSERT(BP_GET_TYPE(zio->io_bp) == DMU_OT_INTENT_LOG);
1223 ASSERT(BP_GET_LEVEL(zio->io_bp) == 0);
1224 ASSERT(BP_GET_BYTEORDER(zio->io_bp) == ZFS_HOST_BYTEORDER);
1225 ASSERT(!BP_IS_GANG(zio->io_bp));
1226 ASSERT(!BP_IS_HOLE(zio->io_bp));
1227 ASSERT(BP_GET_FILL(zio->io_bp) == 0);
1229 abd_put(zio->io_abd);
1231 mutex_enter(&zilog->zl_lock);
1232 ASSERT3S(lwb->lwb_state, ==, LWB_STATE_ISSUED);
1233 lwb->lwb_state = LWB_STATE_WRITE_DONE;
1234 lwb->lwb_write_zio = NULL;
1235 lwb->lwb_fastwrite = FALSE;
1236 nlwb = list_next(&zilog->zl_lwb_list, lwb);
1237 mutex_exit(&zilog->zl_lock);
1239 if (avl_numnodes(t) == 0)
1243 * If there was an IO error, we're not going to call zio_flush()
1244 * on these vdevs, so we simply empty the tree and free the
1245 * nodes. We avoid calling zio_flush() since there isn't any
1246 * good reason for doing so, after the lwb block failed to be
1249 if (zio->io_error != 0) {
1250 while ((zv = avl_destroy_nodes(t, &cookie)) != NULL)
1251 kmem_free(zv, sizeof (*zv));
1256 * If this lwb does not have any threads waiting for it to
1257 * complete, we want to defer issuing the DKIOCFLUSHWRITECACHE
1258 * command to the vdevs written to by "this" lwb, and instead
1259 * rely on the "next" lwb to handle the DKIOCFLUSHWRITECACHE
1260 * command for those vdevs. Thus, we merge the vdev tree of
1261 * "this" lwb with the vdev tree of the "next" lwb in the list,
1262 * and assume the "next" lwb will handle flushing the vdevs (or
1263 * deferring the flush(s) again).
1265 * This is a useful performance optimization, especially for
1266 * workloads with lots of async write activity and few sync
1267 * write and/or fsync activity, as it has the potential to
1268 * coalesce multiple flush commands to a vdev into one.
1270 if (list_head(&lwb->lwb_waiters) == NULL && nlwb != NULL) {
1271 zil_lwb_flush_defer(lwb, nlwb);
1272 ASSERT(avl_is_empty(&lwb->lwb_vdev_tree));
1276 while ((zv = avl_destroy_nodes(t, &cookie)) != NULL) {
1277 vdev_t *vd = vdev_lookup_top(spa, zv->zv_vdev);
1279 zio_flush(lwb->lwb_root_zio, vd);
1280 kmem_free(zv, sizeof (*zv));
1285 zil_lwb_set_zio_dependency(zilog_t *zilog, lwb_t *lwb)
1287 lwb_t *last_lwb_opened = zilog->zl_last_lwb_opened;
1289 ASSERT(MUTEX_HELD(&zilog->zl_issuer_lock));
1290 ASSERT(MUTEX_HELD(&zilog->zl_lock));
1293 * The zilog's "zl_last_lwb_opened" field is used to build the
1294 * lwb/zio dependency chain, which is used to preserve the
1295 * ordering of lwb completions that is required by the semantics
1296 * of the ZIL. Each new lwb zio becomes a parent of the
1297 * "previous" lwb zio, such that the new lwb's zio cannot
1298 * complete until the "previous" lwb's zio completes.
1300 * This is required by the semantics of zil_commit(); the commit
1301 * waiters attached to the lwbs will be woken in the lwb zio's
1302 * completion callback, so this zio dependency graph ensures the
1303 * waiters are woken in the correct order (the same order the
1304 * lwbs were created).
1306 if (last_lwb_opened != NULL &&
1307 last_lwb_opened->lwb_state != LWB_STATE_FLUSH_DONE) {
1308 ASSERT(last_lwb_opened->lwb_state == LWB_STATE_OPENED ||
1309 last_lwb_opened->lwb_state == LWB_STATE_ISSUED ||
1310 last_lwb_opened->lwb_state == LWB_STATE_WRITE_DONE);
1312 ASSERT3P(last_lwb_opened->lwb_root_zio, !=, NULL);
1313 zio_add_child(lwb->lwb_root_zio,
1314 last_lwb_opened->lwb_root_zio);
1317 * If the previous lwb's write hasn't already completed,
1318 * we also want to order the completion of the lwb write
1319 * zios (above, we only order the completion of the lwb
1320 * root zios). This is required because of how we can
1321 * defer the DKIOCFLUSHWRITECACHE commands for each lwb.
1323 * When the DKIOCFLUSHWRITECACHE commands are deferred,
1324 * the previous lwb will rely on this lwb to flush the
1325 * vdevs written to by that previous lwb. Thus, we need
1326 * to ensure this lwb doesn't issue the flush until
1327 * after the previous lwb's write completes. We ensure
1328 * this ordering by setting the zio parent/child
1329 * relationship here.
1331 * Without this relationship on the lwb's write zio,
1332 * it's possible for this lwb's write to complete prior
1333 * to the previous lwb's write completing; and thus, the
1334 * vdevs for the previous lwb would be flushed prior to
1335 * that lwb's data being written to those vdevs (the
1336 * vdevs are flushed in the lwb write zio's completion
1337 * handler, zil_lwb_write_done()).
1339 if (last_lwb_opened->lwb_state != LWB_STATE_WRITE_DONE) {
1340 ASSERT(last_lwb_opened->lwb_state == LWB_STATE_OPENED ||
1341 last_lwb_opened->lwb_state == LWB_STATE_ISSUED);
1343 ASSERT3P(last_lwb_opened->lwb_write_zio, !=, NULL);
1344 zio_add_child(lwb->lwb_write_zio,
1345 last_lwb_opened->lwb_write_zio);
1352 * This function's purpose is to "open" an lwb such that it is ready to
1353 * accept new itxs being committed to it. To do this, the lwb's zio
1354 * structures are created, and linked to the lwb. This function is
1355 * idempotent; if the passed in lwb has already been opened, this
1356 * function is essentially a no-op.
1359 zil_lwb_write_open(zilog_t *zilog, lwb_t *lwb)
1361 zbookmark_phys_t zb;
1362 zio_priority_t prio;
1364 ASSERT(MUTEX_HELD(&zilog->zl_issuer_lock));
1365 ASSERT3P(lwb, !=, NULL);
1366 EQUIV(lwb->lwb_root_zio == NULL, lwb->lwb_state == LWB_STATE_CLOSED);
1367 EQUIV(lwb->lwb_root_zio != NULL, lwb->lwb_state == LWB_STATE_OPENED);
1369 SET_BOOKMARK(&zb, lwb->lwb_blk.blk_cksum.zc_word[ZIL_ZC_OBJSET],
1370 ZB_ZIL_OBJECT, ZB_ZIL_LEVEL,
1371 lwb->lwb_blk.blk_cksum.zc_word[ZIL_ZC_SEQ]);
1373 /* Lock so zil_sync() doesn't fastwrite_unmark after zio is created */
1374 mutex_enter(&zilog->zl_lock);
1375 if (lwb->lwb_root_zio == NULL) {
1376 abd_t *lwb_abd = abd_get_from_buf(lwb->lwb_buf,
1377 BP_GET_LSIZE(&lwb->lwb_blk));
1379 if (!lwb->lwb_fastwrite) {
1380 metaslab_fastwrite_mark(zilog->zl_spa, &lwb->lwb_blk);
1381 lwb->lwb_fastwrite = 1;
1384 if (!lwb->lwb_slog || zilog->zl_cur_used <= zil_slog_bulk)
1385 prio = ZIO_PRIORITY_SYNC_WRITE;
1387 prio = ZIO_PRIORITY_ASYNC_WRITE;
1389 lwb->lwb_root_zio = zio_root(zilog->zl_spa,
1390 zil_lwb_flush_vdevs_done, lwb, ZIO_FLAG_CANFAIL);
1391 ASSERT3P(lwb->lwb_root_zio, !=, NULL);
1393 lwb->lwb_write_zio = zio_rewrite(lwb->lwb_root_zio,
1394 zilog->zl_spa, 0, &lwb->lwb_blk, lwb_abd,
1395 BP_GET_LSIZE(&lwb->lwb_blk), zil_lwb_write_done, lwb,
1396 prio, ZIO_FLAG_CANFAIL | ZIO_FLAG_DONT_PROPAGATE |
1397 ZIO_FLAG_FASTWRITE, &zb);
1398 ASSERT3P(lwb->lwb_write_zio, !=, NULL);
1400 lwb->lwb_state = LWB_STATE_OPENED;
1402 zil_lwb_set_zio_dependency(zilog, lwb);
1403 zilog->zl_last_lwb_opened = lwb;
1405 mutex_exit(&zilog->zl_lock);
1407 ASSERT3P(lwb->lwb_root_zio, !=, NULL);
1408 ASSERT3P(lwb->lwb_write_zio, !=, NULL);
1409 ASSERT3S(lwb->lwb_state, ==, LWB_STATE_OPENED);
1413 * Define a limited set of intent log block sizes.
1415 * These must be a multiple of 4KB. Note only the amount used (again
1416 * aligned to 4KB) actually gets written. However, we can't always just
1417 * allocate SPA_OLD_MAXBLOCKSIZE as the slog space could be exhausted.
1419 uint64_t zil_block_buckets[] = {
1420 4096, /* non TX_WRITE */
1421 8192+4096, /* data base */
1422 32*1024 + 4096, /* NFS writes */
1427 * Start a log block write and advance to the next log block.
1428 * Calls are serialized.
1431 zil_lwb_write_issue(zilog_t *zilog, lwb_t *lwb)
1435 spa_t *spa = zilog->zl_spa;
1439 uint64_t zil_blksz, wsz;
1443 ASSERT(MUTEX_HELD(&zilog->zl_issuer_lock));
1444 ASSERT3P(lwb->lwb_root_zio, !=, NULL);
1445 ASSERT3P(lwb->lwb_write_zio, !=, NULL);
1446 ASSERT3S(lwb->lwb_state, ==, LWB_STATE_OPENED);
1448 if (BP_GET_CHECKSUM(&lwb->lwb_blk) == ZIO_CHECKSUM_ZILOG2) {
1449 zilc = (zil_chain_t *)lwb->lwb_buf;
1450 bp = &zilc->zc_next_blk;
1452 zilc = (zil_chain_t *)(lwb->lwb_buf + lwb->lwb_sz);
1453 bp = &zilc->zc_next_blk;
1456 ASSERT(lwb->lwb_nused <= lwb->lwb_sz);
1459 * Allocate the next block and save its address in this block
1460 * before writing it in order to establish the log chain.
1461 * Note that if the allocation of nlwb synced before we wrote
1462 * the block that points at it (lwb), we'd leak it if we crashed.
1463 * Therefore, we don't do dmu_tx_commit() until zil_lwb_write_done().
1464 * We dirty the dataset to ensure that zil_sync() will be called
1465 * to clean up in the event of allocation failure or I/O failure.
1468 tx = dmu_tx_create(zilog->zl_os);
1471 * Since we are not going to create any new dirty data, and we
1472 * can even help with clearing the existing dirty data, we
1473 * should not be subject to the dirty data based delays. We
1474 * use TXG_NOTHROTTLE to bypass the delay mechanism.
1476 VERIFY0(dmu_tx_assign(tx, TXG_WAIT | TXG_NOTHROTTLE));
1478 dsl_dataset_dirty(dmu_objset_ds(zilog->zl_os), tx);
1479 txg = dmu_tx_get_txg(tx);
1484 * Log blocks are pre-allocated. Here we select the size of the next
1485 * block, based on size used in the last block.
1486 * - first find the smallest bucket that will fit the block from a
1487 * limited set of block sizes. This is because it's faster to write
1488 * blocks allocated from the same metaslab as they are adjacent or
1490 * - next find the maximum from the new suggested size and an array of
1491 * previous sizes. This lessens a picket fence effect of wrongly
1492 * guessing the size if we have a stream of say 2k, 64k, 2k, 64k
1495 * Note we only write what is used, but we can't just allocate
1496 * the maximum block size because we can exhaust the available
1499 zil_blksz = zilog->zl_cur_used + sizeof (zil_chain_t);
1500 for (i = 0; zil_blksz > zil_block_buckets[i]; i++)
1502 zil_blksz = zil_block_buckets[i];
1503 if (zil_blksz == UINT64_MAX)
1504 zil_blksz = SPA_OLD_MAXBLOCKSIZE;
1505 zilog->zl_prev_blks[zilog->zl_prev_rotor] = zil_blksz;
1506 for (i = 0; i < ZIL_PREV_BLKS; i++)
1507 zil_blksz = MAX(zil_blksz, zilog->zl_prev_blks[i]);
1508 zilog->zl_prev_rotor = (zilog->zl_prev_rotor + 1) & (ZIL_PREV_BLKS - 1);
1511 error = zio_alloc_zil(spa, zilog->zl_os, txg, bp, zil_blksz, &slog);
1513 ZIL_STAT_BUMP(zil_itx_metaslab_slog_count);
1514 ZIL_STAT_INCR(zil_itx_metaslab_slog_bytes, lwb->lwb_nused);
1516 ZIL_STAT_BUMP(zil_itx_metaslab_normal_count);
1517 ZIL_STAT_INCR(zil_itx_metaslab_normal_bytes, lwb->lwb_nused);
1520 ASSERT3U(bp->blk_birth, ==, txg);
1521 bp->blk_cksum = lwb->lwb_blk.blk_cksum;
1522 bp->blk_cksum.zc_word[ZIL_ZC_SEQ]++;
1525 * Allocate a new log write block (lwb).
1527 nlwb = zil_alloc_lwb(zilog, bp, slog, txg, TRUE);
1530 if (BP_GET_CHECKSUM(&lwb->lwb_blk) == ZIO_CHECKSUM_ZILOG2) {
1531 /* For Slim ZIL only write what is used. */
1532 wsz = P2ROUNDUP_TYPED(lwb->lwb_nused, ZIL_MIN_BLKSZ, uint64_t);
1533 ASSERT3U(wsz, <=, lwb->lwb_sz);
1534 zio_shrink(lwb->lwb_write_zio, wsz);
1541 zilc->zc_nused = lwb->lwb_nused;
1542 zilc->zc_eck.zec_cksum = lwb->lwb_blk.blk_cksum;
1545 * clear unused data for security
1547 bzero(lwb->lwb_buf + lwb->lwb_nused, wsz - lwb->lwb_nused);
1549 spa_config_enter(zilog->zl_spa, SCL_STATE, lwb, RW_READER);
1551 zil_lwb_add_block(lwb, &lwb->lwb_blk);
1552 lwb->lwb_issued_timestamp = gethrtime();
1553 lwb->lwb_state = LWB_STATE_ISSUED;
1555 zio_nowait(lwb->lwb_root_zio);
1556 zio_nowait(lwb->lwb_write_zio);
1559 * If there was an allocation failure then nlwb will be null which
1560 * forces a txg_wait_synced().
1566 zil_lwb_commit(zilog_t *zilog, itx_t *itx, lwb_t *lwb)
1569 lr_write_t *lrwb, *lrw;
1571 uint64_t dlen, dnow, lwb_sp, reclen, txg;
1573 ASSERT(MUTEX_HELD(&zilog->zl_issuer_lock));
1574 ASSERT3P(lwb, !=, NULL);
1575 ASSERT3P(lwb->lwb_buf, !=, NULL);
1577 zil_lwb_write_open(zilog, lwb);
1580 lrw = (lr_write_t *)lrc;
1583 * A commit itx doesn't represent any on-disk state; instead
1584 * it's simply used as a place holder on the commit list, and
1585 * provides a mechanism for attaching a "commit waiter" onto the
1586 * correct lwb (such that the waiter can be signalled upon
1587 * completion of that lwb). Thus, we don't process this itx's
1588 * log record if it's a commit itx (these itx's don't have log
1589 * records), and instead link the itx's waiter onto the lwb's
1592 * For more details, see the comment above zil_commit().
1594 if (lrc->lrc_txtype == TX_COMMIT) {
1595 mutex_enter(&zilog->zl_lock);
1596 zil_commit_waiter_link_lwb(itx->itx_private, lwb);
1597 itx->itx_private = NULL;
1598 mutex_exit(&zilog->zl_lock);
1602 if (lrc->lrc_txtype == TX_WRITE && itx->itx_wr_state == WR_NEED_COPY) {
1603 dlen = P2ROUNDUP_TYPED(
1604 lrw->lr_length, sizeof (uint64_t), uint64_t);
1608 reclen = lrc->lrc_reclen;
1609 zilog->zl_cur_used += (reclen + dlen);
1612 ASSERT3U(zilog->zl_cur_used, <, UINT64_MAX - (reclen + dlen));
1616 * If this record won't fit in the current log block, start a new one.
1617 * For WR_NEED_COPY optimize layout for minimal number of chunks.
1619 lwb_sp = lwb->lwb_sz - lwb->lwb_nused;
1620 if (reclen > lwb_sp || (reclen + dlen > lwb_sp &&
1621 lwb_sp < ZIL_MAX_WASTE_SPACE && (dlen % ZIL_MAX_LOG_DATA == 0 ||
1622 lwb_sp < reclen + dlen % ZIL_MAX_LOG_DATA))) {
1623 lwb = zil_lwb_write_issue(zilog, lwb);
1626 zil_lwb_write_open(zilog, lwb);
1627 ASSERT(LWB_EMPTY(lwb));
1628 lwb_sp = lwb->lwb_sz - lwb->lwb_nused;
1629 ASSERT3U(reclen + MIN(dlen, sizeof (uint64_t)), <=, lwb_sp);
1632 dnow = MIN(dlen, lwb_sp - reclen);
1633 lr_buf = lwb->lwb_buf + lwb->lwb_nused;
1634 bcopy(lrc, lr_buf, reclen);
1635 lrcb = (lr_t *)lr_buf; /* Like lrc, but inside lwb. */
1636 lrwb = (lr_write_t *)lrcb; /* Like lrw, but inside lwb. */
1638 ZIL_STAT_BUMP(zil_itx_count);
1641 * If it's a write, fetch the data or get its blkptr as appropriate.
1643 if (lrc->lrc_txtype == TX_WRITE) {
1644 if (txg > spa_freeze_txg(zilog->zl_spa))
1645 txg_wait_synced(zilog->zl_dmu_pool, txg);
1646 if (itx->itx_wr_state == WR_COPIED) {
1647 ZIL_STAT_BUMP(zil_itx_copied_count);
1648 ZIL_STAT_INCR(zil_itx_copied_bytes, lrw->lr_length);
1653 if (itx->itx_wr_state == WR_NEED_COPY) {
1654 dbuf = lr_buf + reclen;
1655 lrcb->lrc_reclen += dnow;
1656 if (lrwb->lr_length > dnow)
1657 lrwb->lr_length = dnow;
1658 lrw->lr_offset += dnow;
1659 lrw->lr_length -= dnow;
1660 ZIL_STAT_BUMP(zil_itx_needcopy_count);
1661 ZIL_STAT_INCR(zil_itx_needcopy_bytes, dnow);
1663 ASSERT3S(itx->itx_wr_state, ==, WR_INDIRECT);
1665 ZIL_STAT_BUMP(zil_itx_indirect_count);
1666 ZIL_STAT_INCR(zil_itx_indirect_bytes,
1671 * We pass in the "lwb_write_zio" rather than
1672 * "lwb_root_zio" so that the "lwb_write_zio"
1673 * becomes the parent of any zio's created by
1674 * the "zl_get_data" callback. The vdevs are
1675 * flushed after the "lwb_write_zio" completes,
1676 * so we want to make sure that completion
1677 * callback waits for these additional zio's,
1678 * such that the vdevs used by those zio's will
1679 * be included in the lwb's vdev tree, and those
1680 * vdevs will be properly flushed. If we passed
1681 * in "lwb_root_zio" here, then these additional
1682 * vdevs may not be flushed; e.g. if these zio's
1683 * completed after "lwb_write_zio" completed.
1685 error = zilog->zl_get_data(itx->itx_private,
1686 lrwb, dbuf, lwb, lwb->lwb_write_zio);
1689 txg_wait_synced(zilog->zl_dmu_pool, txg);
1693 ASSERT(error == ENOENT || error == EEXIST ||
1701 * We're actually making an entry, so update lrc_seq to be the
1702 * log record sequence number. Note that this is generally not
1703 * equal to the itx sequence number because not all transactions
1704 * are synchronous, and sometimes spa_sync() gets there first.
1706 lrcb->lrc_seq = ++zilog->zl_lr_seq;
1707 lwb->lwb_nused += reclen + dnow;
1709 zil_lwb_add_txg(lwb, txg);
1711 ASSERT3U(lwb->lwb_nused, <=, lwb->lwb_sz);
1712 ASSERT0(P2PHASE(lwb->lwb_nused, sizeof (uint64_t)));
1716 zilog->zl_cur_used += reclen;
1724 zil_itx_create(uint64_t txtype, size_t lrsize)
1729 lrsize = P2ROUNDUP_TYPED(lrsize, sizeof (uint64_t), size_t);
1730 itxsize = offsetof(itx_t, itx_lr) + lrsize;
1732 itx = zio_data_buf_alloc(itxsize);
1733 itx->itx_lr.lrc_txtype = txtype;
1734 itx->itx_lr.lrc_reclen = lrsize;
1735 itx->itx_lr.lrc_seq = 0; /* defensive */
1736 itx->itx_sync = B_TRUE; /* default is synchronous */
1737 itx->itx_callback = NULL;
1738 itx->itx_callback_data = NULL;
1739 itx->itx_size = itxsize;
1745 zil_itx_destroy(itx_t *itx)
1747 IMPLY(itx->itx_lr.lrc_txtype == TX_COMMIT, itx->itx_callback == NULL);
1748 IMPLY(itx->itx_callback != NULL, itx->itx_lr.lrc_txtype != TX_COMMIT);
1750 if (itx->itx_callback != NULL)
1751 itx->itx_callback(itx->itx_callback_data);
1753 zio_data_buf_free(itx, itx->itx_size);
1757 * Free up the sync and async itxs. The itxs_t has already been detached
1758 * so no locks are needed.
1761 zil_itxg_clean(itxs_t *itxs)
1767 itx_async_node_t *ian;
1769 list = &itxs->i_sync_list;
1770 while ((itx = list_head(list)) != NULL) {
1772 * In the general case, commit itxs will not be found
1773 * here, as they'll be committed to an lwb via
1774 * zil_lwb_commit(), and free'd in that function. Having
1775 * said that, it is still possible for commit itxs to be
1776 * found here, due to the following race:
1778 * - a thread calls zil_commit() which assigns the
1779 * commit itx to a per-txg i_sync_list
1780 * - zil_itxg_clean() is called (e.g. via spa_sync())
1781 * while the waiter is still on the i_sync_list
1783 * There's nothing to prevent syncing the txg while the
1784 * waiter is on the i_sync_list. This normally doesn't
1785 * happen because spa_sync() is slower than zil_commit(),
1786 * but if zil_commit() calls txg_wait_synced() (e.g.
1787 * because zil_create() or zil_commit_writer_stall() is
1788 * called) we will hit this case.
1790 if (itx->itx_lr.lrc_txtype == TX_COMMIT)
1791 zil_commit_waiter_skip(itx->itx_private);
1793 list_remove(list, itx);
1794 zil_itx_destroy(itx);
1798 t = &itxs->i_async_tree;
1799 while ((ian = avl_destroy_nodes(t, &cookie)) != NULL) {
1800 list = &ian->ia_list;
1801 while ((itx = list_head(list)) != NULL) {
1802 list_remove(list, itx);
1803 /* commit itxs should never be on the async lists. */
1804 ASSERT3U(itx->itx_lr.lrc_txtype, !=, TX_COMMIT);
1805 zil_itx_destroy(itx);
1808 kmem_free(ian, sizeof (itx_async_node_t));
1812 kmem_free(itxs, sizeof (itxs_t));
1816 zil_aitx_compare(const void *x1, const void *x2)
1818 const uint64_t o1 = ((itx_async_node_t *)x1)->ia_foid;
1819 const uint64_t o2 = ((itx_async_node_t *)x2)->ia_foid;
1821 return (AVL_CMP(o1, o2));
1825 * Remove all async itx with the given oid.
1828 zil_remove_async(zilog_t *zilog, uint64_t oid)
1831 itx_async_node_t *ian;
1838 list_create(&clean_list, sizeof (itx_t), offsetof(itx_t, itx_node));
1840 if (spa_freeze_txg(zilog->zl_spa) != UINT64_MAX) /* ziltest support */
1843 otxg = spa_last_synced_txg(zilog->zl_spa) + 1;
1845 for (txg = otxg; txg < (otxg + TXG_CONCURRENT_STATES); txg++) {
1846 itxg_t *itxg = &zilog->zl_itxg[txg & TXG_MASK];
1848 mutex_enter(&itxg->itxg_lock);
1849 if (itxg->itxg_txg != txg) {
1850 mutex_exit(&itxg->itxg_lock);
1855 * Locate the object node and append its list.
1857 t = &itxg->itxg_itxs->i_async_tree;
1858 ian = avl_find(t, &oid, &where);
1860 list_move_tail(&clean_list, &ian->ia_list);
1861 mutex_exit(&itxg->itxg_lock);
1863 while ((itx = list_head(&clean_list)) != NULL) {
1864 list_remove(&clean_list, itx);
1865 /* commit itxs should never be on the async lists. */
1866 ASSERT3U(itx->itx_lr.lrc_txtype, !=, TX_COMMIT);
1867 zil_itx_destroy(itx);
1869 list_destroy(&clean_list);
1873 zil_itx_assign(zilog_t *zilog, itx_t *itx, dmu_tx_t *tx)
1877 itxs_t *itxs, *clean = NULL;
1880 * Object ids can be re-instantiated in the next txg so
1881 * remove any async transactions to avoid future leaks.
1882 * This can happen if a fsync occurs on the re-instantiated
1883 * object for a WR_INDIRECT or WR_NEED_COPY write, which gets
1884 * the new file data and flushes a write record for the old object.
1886 if ((itx->itx_lr.lrc_txtype & ~TX_CI) == TX_REMOVE)
1887 zil_remove_async(zilog, itx->itx_oid);
1890 * Ensure the data of a renamed file is committed before the rename.
1892 if ((itx->itx_lr.lrc_txtype & ~TX_CI) == TX_RENAME)
1893 zil_async_to_sync(zilog, itx->itx_oid);
1895 if (spa_freeze_txg(zilog->zl_spa) != UINT64_MAX)
1898 txg = dmu_tx_get_txg(tx);
1900 itxg = &zilog->zl_itxg[txg & TXG_MASK];
1901 mutex_enter(&itxg->itxg_lock);
1902 itxs = itxg->itxg_itxs;
1903 if (itxg->itxg_txg != txg) {
1906 * The zil_clean callback hasn't got around to cleaning
1907 * this itxg. Save the itxs for release below.
1908 * This should be rare.
1910 zfs_dbgmsg("zil_itx_assign: missed itx cleanup for "
1911 "txg %llu", itxg->itxg_txg);
1912 clean = itxg->itxg_itxs;
1914 itxg->itxg_txg = txg;
1915 itxs = itxg->itxg_itxs = kmem_zalloc(sizeof (itxs_t),
1918 list_create(&itxs->i_sync_list, sizeof (itx_t),
1919 offsetof(itx_t, itx_node));
1920 avl_create(&itxs->i_async_tree, zil_aitx_compare,
1921 sizeof (itx_async_node_t),
1922 offsetof(itx_async_node_t, ia_node));
1924 if (itx->itx_sync) {
1925 list_insert_tail(&itxs->i_sync_list, itx);
1927 avl_tree_t *t = &itxs->i_async_tree;
1929 LR_FOID_GET_OBJ(((lr_ooo_t *)&itx->itx_lr)->lr_foid);
1930 itx_async_node_t *ian;
1933 ian = avl_find(t, &foid, &where);
1935 ian = kmem_alloc(sizeof (itx_async_node_t),
1937 list_create(&ian->ia_list, sizeof (itx_t),
1938 offsetof(itx_t, itx_node));
1939 ian->ia_foid = foid;
1940 avl_insert(t, ian, where);
1942 list_insert_tail(&ian->ia_list, itx);
1945 itx->itx_lr.lrc_txg = dmu_tx_get_txg(tx);
1948 * We don't want to dirty the ZIL using ZILTEST_TXG, because
1949 * zil_clean() will never be called using ZILTEST_TXG. Thus, we
1950 * need to be careful to always dirty the ZIL using the "real"
1951 * TXG (not itxg_txg) even when the SPA is frozen.
1953 zilog_dirty(zilog, dmu_tx_get_txg(tx));
1954 mutex_exit(&itxg->itxg_lock);
1956 /* Release the old itxs now we've dropped the lock */
1958 zil_itxg_clean(clean);
1962 * If there are any in-memory intent log transactions which have now been
1963 * synced then start up a taskq to free them. We should only do this after we
1964 * have written out the uberblocks (i.e. txg has been comitted) so that
1965 * don't inadvertently clean out in-memory log records that would be required
1969 zil_clean(zilog_t *zilog, uint64_t synced_txg)
1971 itxg_t *itxg = &zilog->zl_itxg[synced_txg & TXG_MASK];
1974 ASSERT3U(synced_txg, <, ZILTEST_TXG);
1976 mutex_enter(&itxg->itxg_lock);
1977 if (itxg->itxg_itxs == NULL || itxg->itxg_txg == ZILTEST_TXG) {
1978 mutex_exit(&itxg->itxg_lock);
1981 ASSERT3U(itxg->itxg_txg, <=, synced_txg);
1982 ASSERT3U(itxg->itxg_txg, !=, 0);
1983 clean_me = itxg->itxg_itxs;
1984 itxg->itxg_itxs = NULL;
1986 mutex_exit(&itxg->itxg_lock);
1988 * Preferably start a task queue to free up the old itxs but
1989 * if taskq_dispatch can't allocate resources to do that then
1990 * free it in-line. This should be rare. Note, using TQ_SLEEP
1991 * created a bad performance problem.
1993 ASSERT3P(zilog->zl_dmu_pool, !=, NULL);
1994 ASSERT3P(zilog->zl_dmu_pool->dp_zil_clean_taskq, !=, NULL);
1995 taskqid_t id = taskq_dispatch(zilog->zl_dmu_pool->dp_zil_clean_taskq,
1996 (void (*)(void *))zil_itxg_clean, clean_me, TQ_NOSLEEP);
1997 if (id == TASKQID_INVALID)
1998 zil_itxg_clean(clean_me);
2002 * This function will traverse the queue of itxs that need to be
2003 * committed, and move them onto the ZIL's zl_itx_commit_list.
2006 zil_get_commit_list(zilog_t *zilog)
2009 list_t *commit_list = &zilog->zl_itx_commit_list;
2011 ASSERT(MUTEX_HELD(&zilog->zl_issuer_lock));
2013 if (spa_freeze_txg(zilog->zl_spa) != UINT64_MAX) /* ziltest support */
2016 otxg = spa_last_synced_txg(zilog->zl_spa) + 1;
2019 * This is inherently racy, since there is nothing to prevent
2020 * the last synced txg from changing. That's okay since we'll
2021 * only commit things in the future.
2023 for (txg = otxg; txg < (otxg + TXG_CONCURRENT_STATES); txg++) {
2024 itxg_t *itxg = &zilog->zl_itxg[txg & TXG_MASK];
2026 mutex_enter(&itxg->itxg_lock);
2027 if (itxg->itxg_txg != txg) {
2028 mutex_exit(&itxg->itxg_lock);
2033 * If we're adding itx records to the zl_itx_commit_list,
2034 * then the zil better be dirty in this "txg". We can assert
2035 * that here since we're holding the itxg_lock which will
2036 * prevent spa_sync from cleaning it. Once we add the itxs
2037 * to the zl_itx_commit_list we must commit it to disk even
2038 * if it's unnecessary (i.e. the txg was synced).
2040 ASSERT(zilog_is_dirty_in_txg(zilog, txg) ||
2041 spa_freeze_txg(zilog->zl_spa) != UINT64_MAX);
2042 list_move_tail(commit_list, &itxg->itxg_itxs->i_sync_list);
2044 mutex_exit(&itxg->itxg_lock);
2049 * Move the async itxs for a specified object to commit into sync lists.
2052 zil_async_to_sync(zilog_t *zilog, uint64_t foid)
2055 itx_async_node_t *ian;
2059 if (spa_freeze_txg(zilog->zl_spa) != UINT64_MAX) /* ziltest support */
2062 otxg = spa_last_synced_txg(zilog->zl_spa) + 1;
2065 * This is inherently racy, since there is nothing to prevent
2066 * the last synced txg from changing.
2068 for (txg = otxg; txg < (otxg + TXG_CONCURRENT_STATES); txg++) {
2069 itxg_t *itxg = &zilog->zl_itxg[txg & TXG_MASK];
2071 mutex_enter(&itxg->itxg_lock);
2072 if (itxg->itxg_txg != txg) {
2073 mutex_exit(&itxg->itxg_lock);
2078 * If a foid is specified then find that node and append its
2079 * list. Otherwise walk the tree appending all the lists
2080 * to the sync list. We add to the end rather than the
2081 * beginning to ensure the create has happened.
2083 t = &itxg->itxg_itxs->i_async_tree;
2085 ian = avl_find(t, &foid, &where);
2087 list_move_tail(&itxg->itxg_itxs->i_sync_list,
2091 void *cookie = NULL;
2093 while ((ian = avl_destroy_nodes(t, &cookie)) != NULL) {
2094 list_move_tail(&itxg->itxg_itxs->i_sync_list,
2096 list_destroy(&ian->ia_list);
2097 kmem_free(ian, sizeof (itx_async_node_t));
2100 mutex_exit(&itxg->itxg_lock);
2105 * This function will prune commit itxs that are at the head of the
2106 * commit list (it won't prune past the first non-commit itx), and
2107 * either: a) attach them to the last lwb that's still pending
2108 * completion, or b) skip them altogether.
2110 * This is used as a performance optimization to prevent commit itxs
2111 * from generating new lwbs when it's unnecessary to do so.
2114 zil_prune_commit_list(zilog_t *zilog)
2118 ASSERT(MUTEX_HELD(&zilog->zl_issuer_lock));
2120 while ((itx = list_head(&zilog->zl_itx_commit_list)) != NULL) {
2121 lr_t *lrc = &itx->itx_lr;
2122 if (lrc->lrc_txtype != TX_COMMIT)
2125 mutex_enter(&zilog->zl_lock);
2127 lwb_t *last_lwb = zilog->zl_last_lwb_opened;
2128 if (last_lwb == NULL ||
2129 last_lwb->lwb_state == LWB_STATE_FLUSH_DONE) {
2131 * All of the itxs this waiter was waiting on
2132 * must have already completed (or there were
2133 * never any itx's for it to wait on), so it's
2134 * safe to skip this waiter and mark it done.
2136 zil_commit_waiter_skip(itx->itx_private);
2138 zil_commit_waiter_link_lwb(itx->itx_private, last_lwb);
2139 itx->itx_private = NULL;
2142 mutex_exit(&zilog->zl_lock);
2144 list_remove(&zilog->zl_itx_commit_list, itx);
2145 zil_itx_destroy(itx);
2148 IMPLY(itx != NULL, itx->itx_lr.lrc_txtype != TX_COMMIT);
2152 zil_commit_writer_stall(zilog_t *zilog)
2155 * When zio_alloc_zil() fails to allocate the next lwb block on
2156 * disk, we must call txg_wait_synced() to ensure all of the
2157 * lwbs in the zilog's zl_lwb_list are synced and then freed (in
2158 * zil_sync()), such that any subsequent ZIL writer (i.e. a call
2159 * to zil_process_commit_list()) will have to call zil_create(),
2160 * and start a new ZIL chain.
2162 * Since zil_alloc_zil() failed, the lwb that was previously
2163 * issued does not have a pointer to the "next" lwb on disk.
2164 * Thus, if another ZIL writer thread was to allocate the "next"
2165 * on-disk lwb, that block could be leaked in the event of a
2166 * crash (because the previous lwb on-disk would not point to
2169 * We must hold the zilog's zl_issuer_lock while we do this, to
2170 * ensure no new threads enter zil_process_commit_list() until
2171 * all lwb's in the zl_lwb_list have been synced and freed
2172 * (which is achieved via the txg_wait_synced() call).
2174 ASSERT(MUTEX_HELD(&zilog->zl_issuer_lock));
2175 txg_wait_synced(zilog->zl_dmu_pool, 0);
2176 ASSERT3P(list_tail(&zilog->zl_lwb_list), ==, NULL);
2180 * This function will traverse the commit list, creating new lwbs as
2181 * needed, and committing the itxs from the commit list to these newly
2182 * created lwbs. Additionally, as a new lwb is created, the previous
2183 * lwb will be issued to the zio layer to be written to disk.
2186 zil_process_commit_list(zilog_t *zilog)
2188 spa_t *spa = zilog->zl_spa;
2190 list_t nolwb_waiters;
2194 ASSERT(MUTEX_HELD(&zilog->zl_issuer_lock));
2197 * Return if there's nothing to commit before we dirty the fs by
2198 * calling zil_create().
2200 if (list_head(&zilog->zl_itx_commit_list) == NULL)
2203 list_create(&nolwb_itxs, sizeof (itx_t), offsetof(itx_t, itx_node));
2204 list_create(&nolwb_waiters, sizeof (zil_commit_waiter_t),
2205 offsetof(zil_commit_waiter_t, zcw_node));
2207 lwb = list_tail(&zilog->zl_lwb_list);
2209 lwb = zil_create(zilog);
2211 ASSERT3S(lwb->lwb_state, !=, LWB_STATE_ISSUED);
2212 ASSERT3S(lwb->lwb_state, !=, LWB_STATE_WRITE_DONE);
2213 ASSERT3S(lwb->lwb_state, !=, LWB_STATE_FLUSH_DONE);
2216 while ((itx = list_head(&zilog->zl_itx_commit_list)) != NULL) {
2217 lr_t *lrc = &itx->itx_lr;
2218 uint64_t txg = lrc->lrc_txg;
2220 ASSERT3U(txg, !=, 0);
2222 if (lrc->lrc_txtype == TX_COMMIT) {
2223 DTRACE_PROBE2(zil__process__commit__itx,
2224 zilog_t *, zilog, itx_t *, itx);
2226 DTRACE_PROBE2(zil__process__normal__itx,
2227 zilog_t *, zilog, itx_t *, itx);
2230 list_remove(&zilog->zl_itx_commit_list, itx);
2232 boolean_t synced = txg <= spa_last_synced_txg(spa);
2233 boolean_t frozen = txg > spa_freeze_txg(spa);
2236 * If the txg of this itx has already been synced out, then
2237 * we don't need to commit this itx to an lwb. This is
2238 * because the data of this itx will have already been
2239 * written to the main pool. This is inherently racy, and
2240 * it's still ok to commit an itx whose txg has already
2241 * been synced; this will result in a write that's
2242 * unnecessary, but will do no harm.
2244 * With that said, we always want to commit TX_COMMIT itxs
2245 * to an lwb, regardless of whether or not that itx's txg
2246 * has been synced out. We do this to ensure any OPENED lwb
2247 * will always have at least one zil_commit_waiter_t linked
2250 * As a counter-example, if we skipped TX_COMMIT itx's
2251 * whose txg had already been synced, the following
2252 * situation could occur if we happened to be racing with
2255 * 1. We commit a non-TX_COMMIT itx to an lwb, where the
2256 * itx's txg is 10 and the last synced txg is 9.
2257 * 2. spa_sync finishes syncing out txg 10.
2258 * 3. We move to the next itx in the list, it's a TX_COMMIT
2259 * whose txg is 10, so we skip it rather than committing
2260 * it to the lwb used in (1).
2262 * If the itx that is skipped in (3) is the last TX_COMMIT
2263 * itx in the commit list, than it's possible for the lwb
2264 * used in (1) to remain in the OPENED state indefinitely.
2266 * To prevent the above scenario from occurring, ensuring
2267 * that once an lwb is OPENED it will transition to ISSUED
2268 * and eventually DONE, we always commit TX_COMMIT itx's to
2269 * an lwb here, even if that itx's txg has already been
2272 * Finally, if the pool is frozen, we _always_ commit the
2273 * itx. The point of freezing the pool is to prevent data
2274 * from being written to the main pool via spa_sync, and
2275 * instead rely solely on the ZIL to persistently store the
2276 * data; i.e. when the pool is frozen, the last synced txg
2277 * value can't be trusted.
2279 if (frozen || !synced || lrc->lrc_txtype == TX_COMMIT) {
2281 lwb = zil_lwb_commit(zilog, itx, lwb);
2284 list_insert_tail(&nolwb_itxs, itx);
2286 list_insert_tail(&lwb->lwb_itxs, itx);
2288 if (lrc->lrc_txtype == TX_COMMIT) {
2289 zil_commit_waiter_link_nolwb(
2290 itx->itx_private, &nolwb_waiters);
2293 list_insert_tail(&nolwb_itxs, itx);
2296 ASSERT3S(lrc->lrc_txtype, !=, TX_COMMIT);
2297 zil_itx_destroy(itx);
2303 * This indicates zio_alloc_zil() failed to allocate the
2304 * "next" lwb on-disk. When this happens, we must stall
2305 * the ZIL write pipeline; see the comment within
2306 * zil_commit_writer_stall() for more details.
2308 zil_commit_writer_stall(zilog);
2311 * Additionally, we have to signal and mark the "nolwb"
2312 * waiters as "done" here, since without an lwb, we
2313 * can't do this via zil_lwb_flush_vdevs_done() like
2316 zil_commit_waiter_t *zcw;
2317 while ((zcw = list_head(&nolwb_waiters)) != NULL) {
2318 zil_commit_waiter_skip(zcw);
2319 list_remove(&nolwb_waiters, zcw);
2323 * And finally, we have to destroy the itx's that
2324 * couldn't be committed to an lwb; this will also call
2325 * the itx's callback if one exists for the itx.
2327 while ((itx = list_head(&nolwb_itxs)) != NULL) {
2328 list_remove(&nolwb_itxs, itx);
2329 zil_itx_destroy(itx);
2332 ASSERT(list_is_empty(&nolwb_waiters));
2333 ASSERT3P(lwb, !=, NULL);
2334 ASSERT3S(lwb->lwb_state, !=, LWB_STATE_ISSUED);
2335 ASSERT3S(lwb->lwb_state, !=, LWB_STATE_WRITE_DONE);
2336 ASSERT3S(lwb->lwb_state, !=, LWB_STATE_FLUSH_DONE);
2339 * At this point, the ZIL block pointed at by the "lwb"
2340 * variable is in one of the following states: "closed"
2343 * If it's "closed", then no itxs have been committed to
2344 * it, so there's no point in issuing its zio (i.e. it's
2347 * If it's "open", then it contains one or more itxs that
2348 * eventually need to be committed to stable storage. In
2349 * this case we intentionally do not issue the lwb's zio
2350 * to disk yet, and instead rely on one of the following
2351 * two mechanisms for issuing the zio:
2353 * 1. Ideally, there will be more ZIL activity occurring
2354 * on the system, such that this function will be
2355 * immediately called again (not necessarily by the same
2356 * thread) and this lwb's zio will be issued via
2357 * zil_lwb_commit(). This way, the lwb is guaranteed to
2358 * be "full" when it is issued to disk, and we'll make
2359 * use of the lwb's size the best we can.
2361 * 2. If there isn't sufficient ZIL activity occurring on
2362 * the system, such that this lwb's zio isn't issued via
2363 * zil_lwb_commit(), zil_commit_waiter() will issue the
2364 * lwb's zio. If this occurs, the lwb is not guaranteed
2365 * to be "full" by the time its zio is issued, and means
2366 * the size of the lwb was "too large" given the amount
2367 * of ZIL activity occurring on the system at that time.
2369 * We do this for a couple of reasons:
2371 * 1. To try and reduce the number of IOPs needed to
2372 * write the same number of itxs. If an lwb has space
2373 * available in its buffer for more itxs, and more itxs
2374 * will be committed relatively soon (relative to the
2375 * latency of performing a write), then it's beneficial
2376 * to wait for these "next" itxs. This way, more itxs
2377 * can be committed to stable storage with fewer writes.
2379 * 2. To try and use the largest lwb block size that the
2380 * incoming rate of itxs can support. Again, this is to
2381 * try and pack as many itxs into as few lwbs as
2382 * possible, without significantly impacting the latency
2383 * of each individual itx.
2389 * This function is responsible for ensuring the passed in commit waiter
2390 * (and associated commit itx) is committed to an lwb. If the waiter is
2391 * not already committed to an lwb, all itxs in the zilog's queue of
2392 * itxs will be processed. The assumption is the passed in waiter's
2393 * commit itx will found in the queue just like the other non-commit
2394 * itxs, such that when the entire queue is processed, the waiter will
2395 * have been committed to an lwb.
2397 * The lwb associated with the passed in waiter is not guaranteed to
2398 * have been issued by the time this function completes. If the lwb is
2399 * not issued, we rely on future calls to zil_commit_writer() to issue
2400 * the lwb, or the timeout mechanism found in zil_commit_waiter().
2403 zil_commit_writer(zilog_t *zilog, zil_commit_waiter_t *zcw)
2405 ASSERT(!MUTEX_HELD(&zilog->zl_lock));
2406 ASSERT(spa_writeable(zilog->zl_spa));
2408 mutex_enter(&zilog->zl_issuer_lock);
2410 if (zcw->zcw_lwb != NULL || zcw->zcw_done) {
2412 * It's possible that, while we were waiting to acquire
2413 * the "zl_issuer_lock", another thread committed this
2414 * waiter to an lwb. If that occurs, we bail out early,
2415 * without processing any of the zilog's queue of itxs.
2417 * On certain workloads and system configurations, the
2418 * "zl_issuer_lock" can become highly contended. In an
2419 * attempt to reduce this contention, we immediately drop
2420 * the lock if the waiter has already been processed.
2422 * We've measured this optimization to reduce CPU spent
2423 * contending on this lock by up to 5%, using a system
2424 * with 32 CPUs, low latency storage (~50 usec writes),
2425 * and 1024 threads performing sync writes.
2430 ZIL_STAT_BUMP(zil_commit_writer_count);
2432 zil_get_commit_list(zilog);
2433 zil_prune_commit_list(zilog);
2434 zil_process_commit_list(zilog);
2437 mutex_exit(&zilog->zl_issuer_lock);
2441 zil_commit_waiter_timeout(zilog_t *zilog, zil_commit_waiter_t *zcw)
2443 ASSERT(!MUTEX_HELD(&zilog->zl_issuer_lock));
2444 ASSERT(MUTEX_HELD(&zcw->zcw_lock));
2445 ASSERT3B(zcw->zcw_done, ==, B_FALSE);
2447 lwb_t *lwb = zcw->zcw_lwb;
2448 ASSERT3P(lwb, !=, NULL);
2449 ASSERT3S(lwb->lwb_state, !=, LWB_STATE_CLOSED);
2452 * If the lwb has already been issued by another thread, we can
2453 * immediately return since there's no work to be done (the
2454 * point of this function is to issue the lwb). Additionally, we
2455 * do this prior to acquiring the zl_issuer_lock, to avoid
2456 * acquiring it when it's not necessary to do so.
2458 if (lwb->lwb_state == LWB_STATE_ISSUED ||
2459 lwb->lwb_state == LWB_STATE_WRITE_DONE ||
2460 lwb->lwb_state == LWB_STATE_FLUSH_DONE)
2464 * In order to call zil_lwb_write_issue() we must hold the
2465 * zilog's "zl_issuer_lock". We can't simply acquire that lock,
2466 * since we're already holding the commit waiter's "zcw_lock",
2467 * and those two locks are acquired in the opposite order
2470 mutex_exit(&zcw->zcw_lock);
2471 mutex_enter(&zilog->zl_issuer_lock);
2472 mutex_enter(&zcw->zcw_lock);
2475 * Since we just dropped and re-acquired the commit waiter's
2476 * lock, we have to re-check to see if the waiter was marked
2477 * "done" during that process. If the waiter was marked "done",
2478 * the "lwb" pointer is no longer valid (it can be free'd after
2479 * the waiter is marked "done"), so without this check we could
2480 * wind up with a use-after-free error below.
2485 ASSERT3P(lwb, ==, zcw->zcw_lwb);
2488 * We've already checked this above, but since we hadn't acquired
2489 * the zilog's zl_issuer_lock, we have to perform this check a
2490 * second time while holding the lock.
2492 * We don't need to hold the zl_lock since the lwb cannot transition
2493 * from OPENED to ISSUED while we hold the zl_issuer_lock. The lwb
2494 * _can_ transition from ISSUED to DONE, but it's OK to race with
2495 * that transition since we treat the lwb the same, whether it's in
2496 * the ISSUED or DONE states.
2498 * The important thing, is we treat the lwb differently depending on
2499 * if it's ISSUED or OPENED, and block any other threads that might
2500 * attempt to issue this lwb. For that reason we hold the
2501 * zl_issuer_lock when checking the lwb_state; we must not call
2502 * zil_lwb_write_issue() if the lwb had already been issued.
2504 * See the comment above the lwb_state_t structure definition for
2505 * more details on the lwb states, and locking requirements.
2507 if (lwb->lwb_state == LWB_STATE_ISSUED ||
2508 lwb->lwb_state == LWB_STATE_WRITE_DONE ||
2509 lwb->lwb_state == LWB_STATE_FLUSH_DONE)
2512 ASSERT3S(lwb->lwb_state, ==, LWB_STATE_OPENED);
2515 * As described in the comments above zil_commit_waiter() and
2516 * zil_process_commit_list(), we need to issue this lwb's zio
2517 * since we've reached the commit waiter's timeout and it still
2518 * hasn't been issued.
2520 lwb_t *nlwb = zil_lwb_write_issue(zilog, lwb);
2522 IMPLY(nlwb != NULL, lwb->lwb_state != LWB_STATE_OPENED);
2525 * Since the lwb's zio hadn't been issued by the time this thread
2526 * reached its timeout, we reset the zilog's "zl_cur_used" field
2527 * to influence the zil block size selection algorithm.
2529 * By having to issue the lwb's zio here, it means the size of the
2530 * lwb was too large, given the incoming throughput of itxs. By
2531 * setting "zl_cur_used" to zero, we communicate this fact to the
2532 * block size selection algorithm, so it can take this information
2533 * into account, and potentially select a smaller size for the
2534 * next lwb block that is allocated.
2536 zilog->zl_cur_used = 0;
2540 * When zil_lwb_write_issue() returns NULL, this
2541 * indicates zio_alloc_zil() failed to allocate the
2542 * "next" lwb on-disk. When this occurs, the ZIL write
2543 * pipeline must be stalled; see the comment within the
2544 * zil_commit_writer_stall() function for more details.
2546 * We must drop the commit waiter's lock prior to
2547 * calling zil_commit_writer_stall() or else we can wind
2548 * up with the following deadlock:
2550 * - This thread is waiting for the txg to sync while
2551 * holding the waiter's lock; txg_wait_synced() is
2552 * used within txg_commit_writer_stall().
2554 * - The txg can't sync because it is waiting for this
2555 * lwb's zio callback to call dmu_tx_commit().
2557 * - The lwb's zio callback can't call dmu_tx_commit()
2558 * because it's blocked trying to acquire the waiter's
2559 * lock, which occurs prior to calling dmu_tx_commit()
2561 mutex_exit(&zcw->zcw_lock);
2562 zil_commit_writer_stall(zilog);
2563 mutex_enter(&zcw->zcw_lock);
2567 mutex_exit(&zilog->zl_issuer_lock);
2568 ASSERT(MUTEX_HELD(&zcw->zcw_lock));
2572 * This function is responsible for performing the following two tasks:
2574 * 1. its primary responsibility is to block until the given "commit
2575 * waiter" is considered "done".
2577 * 2. its secondary responsibility is to issue the zio for the lwb that
2578 * the given "commit waiter" is waiting on, if this function has
2579 * waited "long enough" and the lwb is still in the "open" state.
2581 * Given a sufficient amount of itxs being generated and written using
2582 * the ZIL, the lwb's zio will be issued via the zil_lwb_commit()
2583 * function. If this does not occur, this secondary responsibility will
2584 * ensure the lwb is issued even if there is not other synchronous
2585 * activity on the system.
2587 * For more details, see zil_process_commit_list(); more specifically,
2588 * the comment at the bottom of that function.
2591 zil_commit_waiter(zilog_t *zilog, zil_commit_waiter_t *zcw)
2593 ASSERT(!MUTEX_HELD(&zilog->zl_lock));
2594 ASSERT(!MUTEX_HELD(&zilog->zl_issuer_lock));
2595 ASSERT(spa_writeable(zilog->zl_spa));
2597 mutex_enter(&zcw->zcw_lock);
2600 * The timeout is scaled based on the lwb latency to avoid
2601 * significantly impacting the latency of each individual itx.
2602 * For more details, see the comment at the bottom of the
2603 * zil_process_commit_list() function.
2605 int pct = MAX(zfs_commit_timeout_pct, 1);
2606 hrtime_t sleep = (zilog->zl_last_lwb_latency * pct) / 100;
2607 hrtime_t wakeup = gethrtime() + sleep;
2608 boolean_t timedout = B_FALSE;
2610 while (!zcw->zcw_done) {
2611 ASSERT(MUTEX_HELD(&zcw->zcw_lock));
2613 lwb_t *lwb = zcw->zcw_lwb;
2616 * Usually, the waiter will have a non-NULL lwb field here,
2617 * but it's possible for it to be NULL as a result of
2618 * zil_commit() racing with spa_sync().
2620 * When zil_clean() is called, it's possible for the itxg
2621 * list (which may be cleaned via a taskq) to contain
2622 * commit itxs. When this occurs, the commit waiters linked
2623 * off of these commit itxs will not be committed to an
2624 * lwb. Additionally, these commit waiters will not be
2625 * marked done until zil_commit_waiter_skip() is called via
2628 * Thus, it's possible for this commit waiter (i.e. the
2629 * "zcw" variable) to be found in this "in between" state;
2630 * where it's "zcw_lwb" field is NULL, and it hasn't yet
2631 * been skipped, so it's "zcw_done" field is still B_FALSE.
2633 IMPLY(lwb != NULL, lwb->lwb_state != LWB_STATE_CLOSED);
2635 if (lwb != NULL && lwb->lwb_state == LWB_STATE_OPENED) {
2636 ASSERT3B(timedout, ==, B_FALSE);
2639 * If the lwb hasn't been issued yet, then we
2640 * need to wait with a timeout, in case this
2641 * function needs to issue the lwb after the
2642 * timeout is reached; responsibility (2) from
2643 * the comment above this function.
2645 clock_t timeleft = cv_timedwait_hires(&zcw->zcw_cv,
2646 &zcw->zcw_lock, wakeup, USEC2NSEC(1),
2647 CALLOUT_FLAG_ABSOLUTE);
2649 if (timeleft >= 0 || zcw->zcw_done)
2653 zil_commit_waiter_timeout(zilog, zcw);
2655 if (!zcw->zcw_done) {
2657 * If the commit waiter has already been
2658 * marked "done", it's possible for the
2659 * waiter's lwb structure to have already
2660 * been freed. Thus, we can only reliably
2661 * make these assertions if the waiter
2664 ASSERT3P(lwb, ==, zcw->zcw_lwb);
2665 ASSERT3S(lwb->lwb_state, !=, LWB_STATE_OPENED);
2669 * If the lwb isn't open, then it must have already
2670 * been issued. In that case, there's no need to
2671 * use a timeout when waiting for the lwb to
2674 * Additionally, if the lwb is NULL, the waiter
2675 * will soon be signaled and marked done via
2676 * zil_clean() and zil_itxg_clean(), so no timeout
2681 lwb->lwb_state == LWB_STATE_ISSUED ||
2682 lwb->lwb_state == LWB_STATE_WRITE_DONE ||
2683 lwb->lwb_state == LWB_STATE_FLUSH_DONE);
2684 cv_wait(&zcw->zcw_cv, &zcw->zcw_lock);
2688 mutex_exit(&zcw->zcw_lock);
2691 static zil_commit_waiter_t *
2692 zil_alloc_commit_waiter(void)
2694 zil_commit_waiter_t *zcw = kmem_cache_alloc(zil_zcw_cache, KM_SLEEP);
2696 cv_init(&zcw->zcw_cv, NULL, CV_DEFAULT, NULL);
2697 mutex_init(&zcw->zcw_lock, NULL, MUTEX_DEFAULT, NULL);
2698 list_link_init(&zcw->zcw_node);
2699 zcw->zcw_lwb = NULL;
2700 zcw->zcw_done = B_FALSE;
2701 zcw->zcw_zio_error = 0;
2707 zil_free_commit_waiter(zil_commit_waiter_t *zcw)
2709 ASSERT(!list_link_active(&zcw->zcw_node));
2710 ASSERT3P(zcw->zcw_lwb, ==, NULL);
2711 ASSERT3B(zcw->zcw_done, ==, B_TRUE);
2712 mutex_destroy(&zcw->zcw_lock);
2713 cv_destroy(&zcw->zcw_cv);
2714 kmem_cache_free(zil_zcw_cache, zcw);
2718 * This function is used to create a TX_COMMIT itx and assign it. This
2719 * way, it will be linked into the ZIL's list of synchronous itxs, and
2720 * then later committed to an lwb (or skipped) when
2721 * zil_process_commit_list() is called.
2724 zil_commit_itx_assign(zilog_t *zilog, zil_commit_waiter_t *zcw)
2726 dmu_tx_t *tx = dmu_tx_create(zilog->zl_os);
2727 VERIFY0(dmu_tx_assign(tx, TXG_WAIT));
2729 itx_t *itx = zil_itx_create(TX_COMMIT, sizeof (lr_t));
2730 itx->itx_sync = B_TRUE;
2731 itx->itx_private = zcw;
2733 zil_itx_assign(zilog, itx, tx);
2739 * Commit ZFS Intent Log transactions (itxs) to stable storage.
2741 * When writing ZIL transactions to the on-disk representation of the
2742 * ZIL, the itxs are committed to a Log Write Block (lwb). Multiple
2743 * itxs can be committed to a single lwb. Once a lwb is written and
2744 * committed to stable storage (i.e. the lwb is written, and vdevs have
2745 * been flushed), each itx that was committed to that lwb is also
2746 * considered to be committed to stable storage.
2748 * When an itx is committed to an lwb, the log record (lr_t) contained
2749 * by the itx is copied into the lwb's zio buffer, and once this buffer
2750 * is written to disk, it becomes an on-disk ZIL block.
2752 * As itxs are generated, they're inserted into the ZIL's queue of
2753 * uncommitted itxs. The semantics of zil_commit() are such that it will
2754 * block until all itxs that were in the queue when it was called, are
2755 * committed to stable storage.
2757 * If "foid" is zero, this means all "synchronous" and "asynchronous"
2758 * itxs, for all objects in the dataset, will be committed to stable
2759 * storage prior to zil_commit() returning. If "foid" is non-zero, all
2760 * "synchronous" itxs for all objects, but only "asynchronous" itxs
2761 * that correspond to the foid passed in, will be committed to stable
2762 * storage prior to zil_commit() returning.
2764 * Generally speaking, when zil_commit() is called, the consumer doesn't
2765 * actually care about _all_ of the uncommitted itxs. Instead, they're
2766 * simply trying to waiting for a specific itx to be committed to disk,
2767 * but the interface(s) for interacting with the ZIL don't allow such
2768 * fine-grained communication. A better interface would allow a consumer
2769 * to create and assign an itx, and then pass a reference to this itx to
2770 * zil_commit(); such that zil_commit() would return as soon as that
2771 * specific itx was committed to disk (instead of waiting for _all_
2772 * itxs to be committed).
2774 * When a thread calls zil_commit() a special "commit itx" will be
2775 * generated, along with a corresponding "waiter" for this commit itx.
2776 * zil_commit() will wait on this waiter's CV, such that when the waiter
2777 * is marked done, and signaled, zil_commit() will return.
2779 * This commit itx is inserted into the queue of uncommitted itxs. This
2780 * provides an easy mechanism for determining which itxs were in the
2781 * queue prior to zil_commit() having been called, and which itxs were
2782 * added after zil_commit() was called.
2784 * The commit it is special; it doesn't have any on-disk representation.
2785 * When a commit itx is "committed" to an lwb, the waiter associated
2786 * with it is linked onto the lwb's list of waiters. Then, when that lwb
2787 * completes, each waiter on the lwb's list is marked done and signaled
2788 * -- allowing the thread waiting on the waiter to return from zil_commit().
2790 * It's important to point out a few critical factors that allow us
2791 * to make use of the commit itxs, commit waiters, per-lwb lists of
2792 * commit waiters, and zio completion callbacks like we're doing:
2794 * 1. The list of waiters for each lwb is traversed, and each commit
2795 * waiter is marked "done" and signaled, in the zio completion
2796 * callback of the lwb's zio[*].
2798 * * Actually, the waiters are signaled in the zio completion
2799 * callback of the root zio for the DKIOCFLUSHWRITECACHE commands
2800 * that are sent to the vdevs upon completion of the lwb zio.
2802 * 2. When the itxs are inserted into the ZIL's queue of uncommitted
2803 * itxs, the order in which they are inserted is preserved[*]; as
2804 * itxs are added to the queue, they are added to the tail of
2805 * in-memory linked lists.
2807 * When committing the itxs to lwbs (to be written to disk), they
2808 * are committed in the same order in which the itxs were added to
2809 * the uncommitted queue's linked list(s); i.e. the linked list of
2810 * itxs to commit is traversed from head to tail, and each itx is
2811 * committed to an lwb in that order.
2815 * - the order of "sync" itxs is preserved w.r.t. other
2816 * "sync" itxs, regardless of the corresponding objects.
2817 * - the order of "async" itxs is preserved w.r.t. other
2818 * "async" itxs corresponding to the same object.
2819 * - the order of "async" itxs is *not* preserved w.r.t. other
2820 * "async" itxs corresponding to different objects.
2821 * - the order of "sync" itxs w.r.t. "async" itxs (or vice
2822 * versa) is *not* preserved, even for itxs that correspond
2823 * to the same object.
2825 * For more details, see: zil_itx_assign(), zil_async_to_sync(),
2826 * zil_get_commit_list(), and zil_process_commit_list().
2828 * 3. The lwbs represent a linked list of blocks on disk. Thus, any
2829 * lwb cannot be considered committed to stable storage, until its
2830 * "previous" lwb is also committed to stable storage. This fact,
2831 * coupled with the fact described above, means that itxs are
2832 * committed in (roughly) the order in which they were generated.
2833 * This is essential because itxs are dependent on prior itxs.
2834 * Thus, we *must not* deem an itx as being committed to stable
2835 * storage, until *all* prior itxs have also been committed to
2838 * To enforce this ordering of lwb zio's, while still leveraging as
2839 * much of the underlying storage performance as possible, we rely
2840 * on two fundamental concepts:
2842 * 1. The creation and issuance of lwb zio's is protected by
2843 * the zilog's "zl_issuer_lock", which ensures only a single
2844 * thread is creating and/or issuing lwb's at a time
2845 * 2. The "previous" lwb is a child of the "current" lwb
2846 * (leveraging the zio parent-child dependency graph)
2848 * By relying on this parent-child zio relationship, we can have
2849 * many lwb zio's concurrently issued to the underlying storage,
2850 * but the order in which they complete will be the same order in
2851 * which they were created.
2854 zil_commit(zilog_t *zilog, uint64_t foid)
2857 * We should never attempt to call zil_commit on a snapshot for
2858 * a couple of reasons:
2860 * 1. A snapshot may never be modified, thus it cannot have any
2861 * in-flight itxs that would have modified the dataset.
2863 * 2. By design, when zil_commit() is called, a commit itx will
2864 * be assigned to this zilog; as a result, the zilog will be
2865 * dirtied. We must not dirty the zilog of a snapshot; there's
2866 * checks in the code that enforce this invariant, and will
2867 * cause a panic if it's not upheld.
2869 ASSERT3B(dmu_objset_is_snapshot(zilog->zl_os), ==, B_FALSE);
2871 if (zilog->zl_sync == ZFS_SYNC_DISABLED)
2874 if (!spa_writeable(zilog->zl_spa)) {
2876 * If the SPA is not writable, there should never be any
2877 * pending itxs waiting to be committed to disk. If that
2878 * weren't true, we'd skip writing those itxs out, and
2879 * would break the semantics of zil_commit(); thus, we're
2880 * verifying that truth before we return to the caller.
2882 ASSERT(list_is_empty(&zilog->zl_lwb_list));
2883 ASSERT3P(zilog->zl_last_lwb_opened, ==, NULL);
2884 for (int i = 0; i < TXG_SIZE; i++)
2885 ASSERT3P(zilog->zl_itxg[i].itxg_itxs, ==, NULL);
2890 * If the ZIL is suspended, we don't want to dirty it by calling
2891 * zil_commit_itx_assign() below, nor can we write out
2892 * lwbs like would be done in zil_commit_write(). Thus, we
2893 * simply rely on txg_wait_synced() to maintain the necessary
2894 * semantics, and avoid calling those functions altogether.
2896 if (zilog->zl_suspend > 0) {
2897 txg_wait_synced(zilog->zl_dmu_pool, 0);
2901 zil_commit_impl(zilog, foid);
2905 zil_commit_impl(zilog_t *zilog, uint64_t foid)
2907 ZIL_STAT_BUMP(zil_commit_count);
2910 * Move the "async" itxs for the specified foid to the "sync"
2911 * queues, such that they will be later committed (or skipped)
2912 * to an lwb when zil_process_commit_list() is called.
2914 * Since these "async" itxs must be committed prior to this
2915 * call to zil_commit returning, we must perform this operation
2916 * before we call zil_commit_itx_assign().
2918 zil_async_to_sync(zilog, foid);
2921 * We allocate a new "waiter" structure which will initially be
2922 * linked to the commit itx using the itx's "itx_private" field.
2923 * Since the commit itx doesn't represent any on-disk state,
2924 * when it's committed to an lwb, rather than copying the its
2925 * lr_t into the lwb's buffer, the commit itx's "waiter" will be
2926 * added to the lwb's list of waiters. Then, when the lwb is
2927 * committed to stable storage, each waiter in the lwb's list of
2928 * waiters will be marked "done", and signalled.
2930 * We must create the waiter and assign the commit itx prior to
2931 * calling zil_commit_writer(), or else our specific commit itx
2932 * is not guaranteed to be committed to an lwb prior to calling
2933 * zil_commit_waiter().
2935 zil_commit_waiter_t *zcw = zil_alloc_commit_waiter();
2936 zil_commit_itx_assign(zilog, zcw);
2938 zil_commit_writer(zilog, zcw);
2939 zil_commit_waiter(zilog, zcw);
2941 if (zcw->zcw_zio_error != 0) {
2943 * If there was an error writing out the ZIL blocks that
2944 * this thread is waiting on, then we fallback to
2945 * relying on spa_sync() to write out the data this
2946 * thread is waiting on. Obviously this has performance
2947 * implications, but the expectation is for this to be
2948 * an exceptional case, and shouldn't occur often.
2950 DTRACE_PROBE2(zil__commit__io__error,
2951 zilog_t *, zilog, zil_commit_waiter_t *, zcw);
2952 txg_wait_synced(zilog->zl_dmu_pool, 0);
2955 zil_free_commit_waiter(zcw);
2959 * Called in syncing context to free committed log blocks and update log header.
2962 zil_sync(zilog_t *zilog, dmu_tx_t *tx)
2964 zil_header_t *zh = zil_header_in_syncing_context(zilog);
2965 uint64_t txg = dmu_tx_get_txg(tx);
2966 spa_t *spa = zilog->zl_spa;
2967 uint64_t *replayed_seq = &zilog->zl_replayed_seq[txg & TXG_MASK];
2971 * We don't zero out zl_destroy_txg, so make sure we don't try
2972 * to destroy it twice.
2974 if (spa_sync_pass(spa) != 1)
2977 mutex_enter(&zilog->zl_lock);
2979 ASSERT(zilog->zl_stop_sync == 0);
2981 if (*replayed_seq != 0) {
2982 ASSERT(zh->zh_replay_seq < *replayed_seq);
2983 zh->zh_replay_seq = *replayed_seq;
2987 if (zilog->zl_destroy_txg == txg) {
2988 blkptr_t blk = zh->zh_log;
2990 ASSERT(list_head(&zilog->zl_lwb_list) == NULL);
2992 bzero(zh, sizeof (zil_header_t));
2993 bzero(zilog->zl_replayed_seq, sizeof (zilog->zl_replayed_seq));
2995 if (zilog->zl_keep_first) {
2997 * If this block was part of log chain that couldn't
2998 * be claimed because a device was missing during
2999 * zil_claim(), but that device later returns,
3000 * then this block could erroneously appear valid.
3001 * To guard against this, assign a new GUID to the new
3002 * log chain so it doesn't matter what blk points to.
3004 zil_init_log_chain(zilog, &blk);
3009 while ((lwb = list_head(&zilog->zl_lwb_list)) != NULL) {
3010 zh->zh_log = lwb->lwb_blk;
3011 if (lwb->lwb_buf != NULL || lwb->lwb_max_txg > txg)
3013 list_remove(&zilog->zl_lwb_list, lwb);
3014 zio_free(spa, txg, &lwb->lwb_blk);
3015 zil_free_lwb(zilog, lwb);
3018 * If we don't have anything left in the lwb list then
3019 * we've had an allocation failure and we need to zero
3020 * out the zil_header blkptr so that we don't end
3021 * up freeing the same block twice.
3023 if (list_head(&zilog->zl_lwb_list) == NULL)
3024 BP_ZERO(&zh->zh_log);
3028 * Remove fastwrite on any blocks that have been pre-allocated for
3029 * the next commit. This prevents fastwrite counter pollution by
3030 * unused, long-lived LWBs.
3032 for (; lwb != NULL; lwb = list_next(&zilog->zl_lwb_list, lwb)) {
3033 if (lwb->lwb_fastwrite && !lwb->lwb_write_zio) {
3034 metaslab_fastwrite_unmark(zilog->zl_spa, &lwb->lwb_blk);
3035 lwb->lwb_fastwrite = 0;
3039 mutex_exit(&zilog->zl_lock);
3044 zil_lwb_cons(void *vbuf, void *unused, int kmflag)
3047 list_create(&lwb->lwb_itxs, sizeof (itx_t), offsetof(itx_t, itx_node));
3048 list_create(&lwb->lwb_waiters, sizeof (zil_commit_waiter_t),
3049 offsetof(zil_commit_waiter_t, zcw_node));
3050 avl_create(&lwb->lwb_vdev_tree, zil_lwb_vdev_compare,
3051 sizeof (zil_vdev_node_t), offsetof(zil_vdev_node_t, zv_node));
3052 mutex_init(&lwb->lwb_vdev_lock, NULL, MUTEX_DEFAULT, NULL);
3058 zil_lwb_dest(void *vbuf, void *unused)
3061 mutex_destroy(&lwb->lwb_vdev_lock);
3062 avl_destroy(&lwb->lwb_vdev_tree);
3063 list_destroy(&lwb->lwb_waiters);
3064 list_destroy(&lwb->lwb_itxs);
3070 zil_lwb_cache = kmem_cache_create("zil_lwb_cache",
3071 sizeof (lwb_t), 0, zil_lwb_cons, zil_lwb_dest, NULL, NULL, NULL, 0);
3073 zil_zcw_cache = kmem_cache_create("zil_zcw_cache",
3074 sizeof (zil_commit_waiter_t), 0, NULL, NULL, NULL, NULL, NULL, 0);
3076 zil_ksp = kstat_create("zfs", 0, "zil", "misc",
3077 KSTAT_TYPE_NAMED, sizeof (zil_stats) / sizeof (kstat_named_t),
3078 KSTAT_FLAG_VIRTUAL);
3080 if (zil_ksp != NULL) {
3081 zil_ksp->ks_data = &zil_stats;
3082 kstat_install(zil_ksp);
3089 kmem_cache_destroy(zil_zcw_cache);
3090 kmem_cache_destroy(zil_lwb_cache);
3092 if (zil_ksp != NULL) {
3093 kstat_delete(zil_ksp);
3099 zil_set_sync(zilog_t *zilog, uint64_t sync)
3101 zilog->zl_sync = sync;
3105 zil_set_logbias(zilog_t *zilog, uint64_t logbias)
3107 zilog->zl_logbias = logbias;
3111 zil_alloc(objset_t *os, zil_header_t *zh_phys)
3115 zilog = kmem_zalloc(sizeof (zilog_t), KM_SLEEP);
3117 zilog->zl_header = zh_phys;
3119 zilog->zl_spa = dmu_objset_spa(os);
3120 zilog->zl_dmu_pool = dmu_objset_pool(os);
3121 zilog->zl_destroy_txg = TXG_INITIAL - 1;
3122 zilog->zl_logbias = dmu_objset_logbias(os);
3123 zilog->zl_sync = dmu_objset_syncprop(os);
3124 zilog->zl_dirty_max_txg = 0;
3125 zilog->zl_last_lwb_opened = NULL;
3126 zilog->zl_last_lwb_latency = 0;
3128 mutex_init(&zilog->zl_lock, NULL, MUTEX_DEFAULT, NULL);
3129 mutex_init(&zilog->zl_issuer_lock, NULL, MUTEX_DEFAULT, NULL);
3131 for (int i = 0; i < TXG_SIZE; i++) {
3132 mutex_init(&zilog->zl_itxg[i].itxg_lock, NULL,
3133 MUTEX_DEFAULT, NULL);
3136 list_create(&zilog->zl_lwb_list, sizeof (lwb_t),
3137 offsetof(lwb_t, lwb_node));
3139 list_create(&zilog->zl_itx_commit_list, sizeof (itx_t),
3140 offsetof(itx_t, itx_node));
3142 cv_init(&zilog->zl_cv_suspend, NULL, CV_DEFAULT, NULL);
3148 zil_free(zilog_t *zilog)
3152 zilog->zl_stop_sync = 1;
3154 ASSERT0(zilog->zl_suspend);
3155 ASSERT0(zilog->zl_suspending);
3157 ASSERT(list_is_empty(&zilog->zl_lwb_list));
3158 list_destroy(&zilog->zl_lwb_list);
3160 ASSERT(list_is_empty(&zilog->zl_itx_commit_list));
3161 list_destroy(&zilog->zl_itx_commit_list);
3163 for (i = 0; i < TXG_SIZE; i++) {
3165 * It's possible for an itx to be generated that doesn't dirty
3166 * a txg (e.g. ztest TX_TRUNCATE). So there's no zil_clean()
3167 * callback to remove the entry. We remove those here.
3169 * Also free up the ziltest itxs.
3171 if (zilog->zl_itxg[i].itxg_itxs)
3172 zil_itxg_clean(zilog->zl_itxg[i].itxg_itxs);
3173 mutex_destroy(&zilog->zl_itxg[i].itxg_lock);
3176 mutex_destroy(&zilog->zl_issuer_lock);
3177 mutex_destroy(&zilog->zl_lock);
3179 cv_destroy(&zilog->zl_cv_suspend);
3181 kmem_free(zilog, sizeof (zilog_t));
3185 * Open an intent log.
3188 zil_open(objset_t *os, zil_get_data_t *get_data)
3190 zilog_t *zilog = dmu_objset_zil(os);
3192 ASSERT3P(zilog->zl_get_data, ==, NULL);
3193 ASSERT3P(zilog->zl_last_lwb_opened, ==, NULL);
3194 ASSERT(list_is_empty(&zilog->zl_lwb_list));
3196 zilog->zl_get_data = get_data;
3202 * Close an intent log.
3205 zil_close(zilog_t *zilog)
3210 if (!dmu_objset_is_snapshot(zilog->zl_os)) {
3211 zil_commit(zilog, 0);
3213 ASSERT3P(list_tail(&zilog->zl_lwb_list), ==, NULL);
3214 ASSERT0(zilog->zl_dirty_max_txg);
3215 ASSERT3B(zilog_is_dirty(zilog), ==, B_FALSE);
3218 mutex_enter(&zilog->zl_lock);
3219 lwb = list_tail(&zilog->zl_lwb_list);
3221 txg = zilog->zl_dirty_max_txg;
3223 txg = MAX(zilog->zl_dirty_max_txg, lwb->lwb_max_txg);
3224 mutex_exit(&zilog->zl_lock);
3227 * We need to use txg_wait_synced() to wait long enough for the
3228 * ZIL to be clean, and to wait for all pending lwbs to be
3232 txg_wait_synced(zilog->zl_dmu_pool, txg);
3234 if (zilog_is_dirty(zilog))
3235 zfs_dbgmsg("zil (%px) is dirty, txg %llu", zilog, txg);
3236 if (txg < spa_freeze_txg(zilog->zl_spa))
3237 VERIFY(!zilog_is_dirty(zilog));
3239 zilog->zl_get_data = NULL;
3242 * We should have only one lwb left on the list; remove it now.
3244 mutex_enter(&zilog->zl_lock);
3245 lwb = list_head(&zilog->zl_lwb_list);
3247 ASSERT3P(lwb, ==, list_tail(&zilog->zl_lwb_list));
3248 ASSERT3S(lwb->lwb_state, !=, LWB_STATE_ISSUED);
3250 if (lwb->lwb_fastwrite)
3251 metaslab_fastwrite_unmark(zilog->zl_spa, &lwb->lwb_blk);
3253 list_remove(&zilog->zl_lwb_list, lwb);
3254 zio_buf_free(lwb->lwb_buf, lwb->lwb_sz);
3255 zil_free_lwb(zilog, lwb);
3257 mutex_exit(&zilog->zl_lock);
3260 static char *suspend_tag = "zil suspending";
3263 * Suspend an intent log. While in suspended mode, we still honor
3264 * synchronous semantics, but we rely on txg_wait_synced() to do it.
3265 * On old version pools, we suspend the log briefly when taking a
3266 * snapshot so that it will have an empty intent log.
3268 * Long holds are not really intended to be used the way we do here --
3269 * held for such a short time. A concurrent caller of dsl_dataset_long_held()
3270 * could fail. Therefore we take pains to only put a long hold if it is
3271 * actually necessary. Fortunately, it will only be necessary if the
3272 * objset is currently mounted (or the ZVOL equivalent). In that case it
3273 * will already have a long hold, so we are not really making things any worse.
3275 * Ideally, we would locate the existing long-holder (i.e. the zfsvfs_t or
3276 * zvol_state_t), and use their mechanism to prevent their hold from being
3277 * dropped (e.g. VFS_HOLD()). However, that would be even more pain for
3280 * if cookiep == NULL, this does both the suspend & resume.
3281 * Otherwise, it returns with the dataset "long held", and the cookie
3282 * should be passed into zil_resume().
3285 zil_suspend(const char *osname, void **cookiep)
3289 const zil_header_t *zh;
3292 error = dmu_objset_hold(osname, suspend_tag, &os);
3295 zilog = dmu_objset_zil(os);
3297 mutex_enter(&zilog->zl_lock);
3298 zh = zilog->zl_header;
3300 if (zh->zh_flags & ZIL_REPLAY_NEEDED) { /* unplayed log */
3301 mutex_exit(&zilog->zl_lock);
3302 dmu_objset_rele(os, suspend_tag);
3303 return (SET_ERROR(EBUSY));
3307 * Don't put a long hold in the cases where we can avoid it. This
3308 * is when there is no cookie so we are doing a suspend & resume
3309 * (i.e. called from zil_vdev_offline()), and there's nothing to do
3310 * for the suspend because it's already suspended, or there's no ZIL.
3312 if (cookiep == NULL && !zilog->zl_suspending &&
3313 (zilog->zl_suspend > 0 || BP_IS_HOLE(&zh->zh_log))) {
3314 mutex_exit(&zilog->zl_lock);
3315 dmu_objset_rele(os, suspend_tag);
3319 dsl_dataset_long_hold(dmu_objset_ds(os), suspend_tag);
3320 dsl_pool_rele(dmu_objset_pool(os), suspend_tag);
3322 zilog->zl_suspend++;
3324 if (zilog->zl_suspend > 1) {
3326 * Someone else is already suspending it.
3327 * Just wait for them to finish.
3330 while (zilog->zl_suspending)
3331 cv_wait(&zilog->zl_cv_suspend, &zilog->zl_lock);
3332 mutex_exit(&zilog->zl_lock);
3334 if (cookiep == NULL)
3342 * If there is no pointer to an on-disk block, this ZIL must not
3343 * be active (e.g. filesystem not mounted), so there's nothing
3346 if (BP_IS_HOLE(&zh->zh_log)) {
3347 ASSERT(cookiep != NULL); /* fast path already handled */
3350 mutex_exit(&zilog->zl_lock);
3355 * The ZIL has work to do. Ensure that the associated encryption
3356 * key will remain mapped while we are committing the log by
3357 * grabbing a reference to it. If the key isn't loaded we have no
3358 * choice but to return an error until the wrapping key is loaded.
3360 if (os->os_encrypted &&
3361 dsl_dataset_create_key_mapping(dmu_objset_ds(os)) != 0) {
3362 zilog->zl_suspend--;
3363 mutex_exit(&zilog->zl_lock);
3364 dsl_dataset_long_rele(dmu_objset_ds(os), suspend_tag);
3365 dsl_dataset_rele(dmu_objset_ds(os), suspend_tag);
3366 return (SET_ERROR(EACCES));
3369 zilog->zl_suspending = B_TRUE;
3370 mutex_exit(&zilog->zl_lock);
3373 * We need to use zil_commit_impl to ensure we wait for all
3374 * LWB_STATE_OPENED and LWB_STATE_ISSUED lwbs to be committed
3375 * to disk before proceeding. If we used zil_commit instead, it
3376 * would just call txg_wait_synced(), because zl_suspend is set.
3377 * txg_wait_synced() doesn't wait for these lwb's to be
3378 * LWB_STATE_FLUSH_DONE before returning.
3380 zil_commit_impl(zilog, 0);
3383 * Now that we've ensured all lwb's are LWB_STATE_FLUSH_DONE, we
3384 * use txg_wait_synced() to ensure the data from the zilog has
3385 * migrated to the main pool before calling zil_destroy().
3387 txg_wait_synced(zilog->zl_dmu_pool, 0);
3389 zil_destroy(zilog, B_FALSE);
3391 mutex_enter(&zilog->zl_lock);
3392 zilog->zl_suspending = B_FALSE;
3393 cv_broadcast(&zilog->zl_cv_suspend);
3394 mutex_exit(&zilog->zl_lock);
3396 if (os->os_encrypted)
3397 dsl_dataset_remove_key_mapping(dmu_objset_ds(os));
3399 if (cookiep == NULL)
3407 zil_resume(void *cookie)
3409 objset_t *os = cookie;
3410 zilog_t *zilog = dmu_objset_zil(os);
3412 mutex_enter(&zilog->zl_lock);
3413 ASSERT(zilog->zl_suspend != 0);
3414 zilog->zl_suspend--;
3415 mutex_exit(&zilog->zl_lock);
3416 dsl_dataset_long_rele(dmu_objset_ds(os), suspend_tag);
3417 dsl_dataset_rele(dmu_objset_ds(os), suspend_tag);
3420 typedef struct zil_replay_arg {
3421 zil_replay_func_t **zr_replay;
3423 boolean_t zr_byteswap;
3428 zil_replay_error(zilog_t *zilog, lr_t *lr, int error)
3430 char name[ZFS_MAX_DATASET_NAME_LEN];
3432 zilog->zl_replaying_seq--; /* didn't actually replay this one */
3434 dmu_objset_name(zilog->zl_os, name);
3436 cmn_err(CE_WARN, "ZFS replay transaction error %d, "
3437 "dataset %s, seq 0x%llx, txtype %llu %s\n", error, name,
3438 (u_longlong_t)lr->lrc_seq,
3439 (u_longlong_t)(lr->lrc_txtype & ~TX_CI),
3440 (lr->lrc_txtype & TX_CI) ? "CI" : "");
3446 zil_replay_log_record(zilog_t *zilog, lr_t *lr, void *zra, uint64_t claim_txg)
3448 zil_replay_arg_t *zr = zra;
3449 const zil_header_t *zh = zilog->zl_header;
3450 uint64_t reclen = lr->lrc_reclen;
3451 uint64_t txtype = lr->lrc_txtype;
3454 zilog->zl_replaying_seq = lr->lrc_seq;
3456 if (lr->lrc_seq <= zh->zh_replay_seq) /* already replayed */
3459 if (lr->lrc_txg < claim_txg) /* already committed */
3462 /* Strip case-insensitive bit, still present in log record */
3465 if (txtype == 0 || txtype >= TX_MAX_TYPE)
3466 return (zil_replay_error(zilog, lr, EINVAL));
3469 * If this record type can be logged out of order, the object
3470 * (lr_foid) may no longer exist. That's legitimate, not an error.
3472 if (TX_OOO(txtype)) {
3473 error = dmu_object_info(zilog->zl_os,
3474 LR_FOID_GET_OBJ(((lr_ooo_t *)lr)->lr_foid), NULL);
3475 if (error == ENOENT || error == EEXIST)
3480 * Make a copy of the data so we can revise and extend it.
3482 bcopy(lr, zr->zr_lr, reclen);
3485 * If this is a TX_WRITE with a blkptr, suck in the data.
3487 if (txtype == TX_WRITE && reclen == sizeof (lr_write_t)) {
3488 error = zil_read_log_data(zilog, (lr_write_t *)lr,
3489 zr->zr_lr + reclen);
3491 return (zil_replay_error(zilog, lr, error));
3495 * The log block containing this lr may have been byteswapped
3496 * so that we can easily examine common fields like lrc_txtype.
3497 * However, the log is a mix of different record types, and only the
3498 * replay vectors know how to byteswap their records. Therefore, if
3499 * the lr was byteswapped, undo it before invoking the replay vector.
3501 if (zr->zr_byteswap)
3502 byteswap_uint64_array(zr->zr_lr, reclen);
3505 * We must now do two things atomically: replay this log record,
3506 * and update the log header sequence number to reflect the fact that
3507 * we did so. At the end of each replay function the sequence number
3508 * is updated if we are in replay mode.
3510 error = zr->zr_replay[txtype](zr->zr_arg, zr->zr_lr, zr->zr_byteswap);
3513 * The DMU's dnode layer doesn't see removes until the txg
3514 * commits, so a subsequent claim can spuriously fail with
3515 * EEXIST. So if we receive any error we try syncing out
3516 * any removes then retry the transaction. Note that we
3517 * specify B_FALSE for byteswap now, so we don't do it twice.
3519 txg_wait_synced(spa_get_dsl(zilog->zl_spa), 0);
3520 error = zr->zr_replay[txtype](zr->zr_arg, zr->zr_lr, B_FALSE);
3522 return (zil_replay_error(zilog, lr, error));
3529 zil_incr_blks(zilog_t *zilog, blkptr_t *bp, void *arg, uint64_t claim_txg)
3531 zilog->zl_replay_blks++;
3537 * If this dataset has a non-empty intent log, replay it and destroy it.
3540 zil_replay(objset_t *os, void *arg, zil_replay_func_t *replay_func[TX_MAX_TYPE])
3542 zilog_t *zilog = dmu_objset_zil(os);
3543 const zil_header_t *zh = zilog->zl_header;
3544 zil_replay_arg_t zr;
3546 if ((zh->zh_flags & ZIL_REPLAY_NEEDED) == 0) {
3547 zil_destroy(zilog, B_TRUE);
3551 zr.zr_replay = replay_func;
3553 zr.zr_byteswap = BP_SHOULD_BYTESWAP(&zh->zh_log);
3554 zr.zr_lr = vmem_alloc(2 * SPA_MAXBLOCKSIZE, KM_SLEEP);
3557 * Wait for in-progress removes to sync before starting replay.
3559 txg_wait_synced(zilog->zl_dmu_pool, 0);
3561 zilog->zl_replay = B_TRUE;
3562 zilog->zl_replay_time = ddi_get_lbolt();
3563 ASSERT(zilog->zl_replay_blks == 0);
3564 (void) zil_parse(zilog, zil_incr_blks, zil_replay_log_record, &zr,
3565 zh->zh_claim_txg, B_TRUE);
3566 vmem_free(zr.zr_lr, 2 * SPA_MAXBLOCKSIZE);
3568 zil_destroy(zilog, B_FALSE);
3569 txg_wait_synced(zilog->zl_dmu_pool, zilog->zl_destroy_txg);
3570 zilog->zl_replay = B_FALSE;
3574 zil_replaying(zilog_t *zilog, dmu_tx_t *tx)
3576 if (zilog->zl_sync == ZFS_SYNC_DISABLED)
3579 if (zilog->zl_replay) {
3580 dsl_dataset_dirty(dmu_objset_ds(zilog->zl_os), tx);
3581 zilog->zl_replayed_seq[dmu_tx_get_txg(tx) & TXG_MASK] =
3582 zilog->zl_replaying_seq;
3591 zil_reset(const char *osname, void *arg)
3595 error = zil_suspend(osname, NULL);
3596 /* EACCES means crypto key not loaded */
3597 if ((error == EACCES) || (error == EBUSY))
3598 return (SET_ERROR(error));
3600 return (SET_ERROR(EEXIST));
3604 #if defined(_KERNEL)
3605 EXPORT_SYMBOL(zil_alloc);
3606 EXPORT_SYMBOL(zil_free);
3607 EXPORT_SYMBOL(zil_open);
3608 EXPORT_SYMBOL(zil_close);
3609 EXPORT_SYMBOL(zil_replay);
3610 EXPORT_SYMBOL(zil_replaying);
3611 EXPORT_SYMBOL(zil_destroy);
3612 EXPORT_SYMBOL(zil_destroy_sync);
3613 EXPORT_SYMBOL(zil_itx_create);
3614 EXPORT_SYMBOL(zil_itx_destroy);
3615 EXPORT_SYMBOL(zil_itx_assign);
3616 EXPORT_SYMBOL(zil_commit);
3617 EXPORT_SYMBOL(zil_claim);
3618 EXPORT_SYMBOL(zil_check_log_chain);
3619 EXPORT_SYMBOL(zil_sync);
3620 EXPORT_SYMBOL(zil_clean);
3621 EXPORT_SYMBOL(zil_suspend);
3622 EXPORT_SYMBOL(zil_resume);
3623 EXPORT_SYMBOL(zil_lwb_add_block);
3624 EXPORT_SYMBOL(zil_bp_tree_add);
3625 EXPORT_SYMBOL(zil_set_sync);
3626 EXPORT_SYMBOL(zil_set_logbias);
3629 module_param(zfs_commit_timeout_pct, int, 0644);
3630 MODULE_PARM_DESC(zfs_commit_timeout_pct, "ZIL block open timeout percentage");
3632 module_param(zil_replay_disable, int, 0644);
3633 MODULE_PARM_DESC(zil_replay_disable, "Disable intent logging replay");
3635 module_param(zil_nocacheflush, int, 0644);
3636 MODULE_PARM_DESC(zil_nocacheflush, "Disable ZIL cache flushes");
3638 module_param(zil_slog_bulk, ulong, 0644);
3639 MODULE_PARM_DESC(zil_slog_bulk, "Limit in bytes slog sync writes per commit");