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 https://opensource.org/licenses/CDDL-1.0.
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
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
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_zfs.h>
46 #include <sys/wmsum.h>
49 * The ZFS Intent Log (ZIL) saves "transaction records" (itxs) of system
50 * calls that change the file system. Each itx has enough information to
51 * be able to replay them after a system crash, power loss, or
52 * equivalent failure mode. These are stored in memory until either:
54 * 1. they are committed to the pool by the DMU transaction group
55 * (txg), at which point they can be discarded; or
56 * 2. they are committed to the on-disk ZIL for the dataset being
57 * modified (e.g. due to an fsync, O_DSYNC, or other synchronous
60 * In the event of a crash or power loss, the itxs contained by each
61 * dataset's on-disk ZIL will be replayed when that dataset is first
62 * instantiated (e.g. if the dataset is a normal filesystem, when it is
65 * As hinted at above, there is one ZIL per dataset (both the in-memory
66 * representation, and the on-disk representation). The on-disk format
67 * consists of 3 parts:
69 * - a single, per-dataset, ZIL header; which points to a chain of
70 * - zero or more ZIL blocks; each of which contains
71 * - zero or more ZIL records
73 * A ZIL record holds the information necessary to replay a single
74 * system call transaction. A ZIL block can hold many ZIL records, and
75 * the blocks are chained together, similarly to a singly linked list.
77 * Each ZIL block contains a block pointer (blkptr_t) to the next ZIL
78 * block in the chain, and the ZIL header points to the first block in
81 * Note, there is not a fixed place in the pool to hold these ZIL
82 * blocks; they are dynamically allocated and freed as needed from the
83 * blocks available on the pool, though they can be preferentially
84 * allocated from a dedicated "log" vdev.
88 * This controls the amount of time that a ZIL block (lwb) will remain
89 * "open" when it isn't "full", and it has a thread waiting for it to be
90 * committed to stable storage. Please refer to the zil_commit_waiter()
91 * function (and the comments within it) for more details.
93 static uint_t zfs_commit_timeout_pct = 5;
96 * See zil.h for more information about these fields.
98 static zil_kstat_values_t zil_stats = {
99 { "zil_commit_count", KSTAT_DATA_UINT64 },
100 { "zil_commit_writer_count", KSTAT_DATA_UINT64 },
101 { "zil_itx_count", KSTAT_DATA_UINT64 },
102 { "zil_itx_indirect_count", KSTAT_DATA_UINT64 },
103 { "zil_itx_indirect_bytes", KSTAT_DATA_UINT64 },
104 { "zil_itx_copied_count", KSTAT_DATA_UINT64 },
105 { "zil_itx_copied_bytes", KSTAT_DATA_UINT64 },
106 { "zil_itx_needcopy_count", KSTAT_DATA_UINT64 },
107 { "zil_itx_needcopy_bytes", KSTAT_DATA_UINT64 },
108 { "zil_itx_metaslab_normal_count", KSTAT_DATA_UINT64 },
109 { "zil_itx_metaslab_normal_bytes", KSTAT_DATA_UINT64 },
110 { "zil_itx_metaslab_slog_count", KSTAT_DATA_UINT64 },
111 { "zil_itx_metaslab_slog_bytes", KSTAT_DATA_UINT64 },
114 static zil_sums_t zil_sums_global;
115 static kstat_t *zil_kstats_global;
118 * Disable intent logging replay. This global ZIL switch affects all pools.
120 int zil_replay_disable = 0;
123 * Disable the DKIOCFLUSHWRITECACHE commands that are normally sent to
124 * the disk(s) by the ZIL after an LWB write has completed. Setting this
125 * will cause ZIL corruption on power loss if a volatile out-of-order
126 * write cache is enabled.
128 static int zil_nocacheflush = 0;
131 * Limit SLOG write size per commit executed with synchronous priority.
132 * Any writes above that will be executed with lower (asynchronous) priority
133 * to limit potential SLOG device abuse by single active ZIL writer.
135 static unsigned long zil_slog_bulk = 768 * 1024;
137 static kmem_cache_t *zil_lwb_cache;
138 static kmem_cache_t *zil_zcw_cache;
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 = TREE_CMP(DVA_GET_VDEV(dva1), DVA_GET_VDEV(dva2));
153 return (TREE_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 (void) random_get_pseudo_bytes((void *)&zc->zc_word[ZIL_ZC_GUID_0],
211 sizeof (zc->zc_word[ZIL_ZC_GUID_0]));
212 (void) random_get_pseudo_bytes((void *)&zc->zc_word[ZIL_ZC_GUID_1],
213 sizeof (zc->zc_word[ZIL_ZC_GUID_1]));
214 zc->zc_word[ZIL_ZC_OBJSET] = dmu_objset_id(zilog->zl_os);
215 zc->zc_word[ZIL_ZC_SEQ] = 1ULL;
219 zil_kstats_global_update(kstat_t *ksp, int rw)
221 zil_kstat_values_t *zs = ksp->ks_data;
222 ASSERT3P(&zil_stats, ==, zs);
224 if (rw == KSTAT_WRITE) {
225 return (SET_ERROR(EACCES));
228 zil_kstat_values_update(zs, &zil_sums_global);
234 * Read a log block and make sure it's valid.
237 zil_read_log_block(zilog_t *zilog, boolean_t decrypt, const blkptr_t *bp,
238 blkptr_t *nbp, void *dst, char **end)
240 enum zio_flag zio_flags = ZIO_FLAG_CANFAIL;
241 arc_flags_t aflags = ARC_FLAG_WAIT;
242 arc_buf_t *abuf = NULL;
246 if (zilog->zl_header->zh_claim_txg == 0)
247 zio_flags |= ZIO_FLAG_SPECULATIVE | ZIO_FLAG_SCRUB;
249 if (!(zilog->zl_header->zh_flags & ZIL_CLAIM_LR_SEQ_VALID))
250 zio_flags |= ZIO_FLAG_SPECULATIVE;
253 zio_flags |= ZIO_FLAG_RAW;
255 SET_BOOKMARK(&zb, bp->blk_cksum.zc_word[ZIL_ZC_OBJSET],
256 ZB_ZIL_OBJECT, ZB_ZIL_LEVEL, bp->blk_cksum.zc_word[ZIL_ZC_SEQ]);
258 error = arc_read(NULL, zilog->zl_spa, bp, arc_getbuf_func,
259 &abuf, ZIO_PRIORITY_SYNC_READ, zio_flags, &aflags, &zb);
262 zio_cksum_t cksum = bp->blk_cksum;
265 * Validate the checksummed log block.
267 * Sequence numbers should be... sequential. The checksum
268 * verifier for the next block should be bp's checksum plus 1.
270 * Also check the log chain linkage and size used.
272 cksum.zc_word[ZIL_ZC_SEQ]++;
274 if (BP_GET_CHECKSUM(bp) == ZIO_CHECKSUM_ZILOG2) {
275 zil_chain_t *zilc = abuf->b_data;
276 char *lr = (char *)(zilc + 1);
277 uint64_t len = zilc->zc_nused - sizeof (zil_chain_t);
279 if (memcmp(&cksum, &zilc->zc_next_blk.blk_cksum,
280 sizeof (cksum)) || BP_IS_HOLE(&zilc->zc_next_blk)) {
281 error = SET_ERROR(ECKSUM);
283 ASSERT3U(len, <=, SPA_OLD_MAXBLOCKSIZE);
284 memcpy(dst, lr, len);
285 *end = (char *)dst + len;
286 *nbp = zilc->zc_next_blk;
289 char *lr = abuf->b_data;
290 uint64_t size = BP_GET_LSIZE(bp);
291 zil_chain_t *zilc = (zil_chain_t *)(lr + size) - 1;
293 if (memcmp(&cksum, &zilc->zc_next_blk.blk_cksum,
294 sizeof (cksum)) || BP_IS_HOLE(&zilc->zc_next_blk) ||
295 (zilc->zc_nused > (size - sizeof (*zilc)))) {
296 error = SET_ERROR(ECKSUM);
298 ASSERT3U(zilc->zc_nused, <=,
299 SPA_OLD_MAXBLOCKSIZE);
300 memcpy(dst, lr, zilc->zc_nused);
301 *end = (char *)dst + zilc->zc_nused;
302 *nbp = zilc->zc_next_blk;
306 arc_buf_destroy(abuf, &abuf);
313 * Read a TX_WRITE log data block.
316 zil_read_log_data(zilog_t *zilog, const lr_write_t *lr, void *wbuf)
318 enum zio_flag zio_flags = ZIO_FLAG_CANFAIL;
319 const blkptr_t *bp = &lr->lr_blkptr;
320 arc_flags_t aflags = ARC_FLAG_WAIT;
321 arc_buf_t *abuf = NULL;
325 if (BP_IS_HOLE(bp)) {
327 memset(wbuf, 0, MAX(BP_GET_LSIZE(bp), lr->lr_length));
331 if (zilog->zl_header->zh_claim_txg == 0)
332 zio_flags |= ZIO_FLAG_SPECULATIVE | ZIO_FLAG_SCRUB;
335 * If we are not using the resulting data, we are just checking that
336 * it hasn't been corrupted so we don't need to waste CPU time
337 * decompressing and decrypting it.
340 zio_flags |= ZIO_FLAG_RAW;
342 SET_BOOKMARK(&zb, dmu_objset_id(zilog->zl_os), lr->lr_foid,
343 ZB_ZIL_LEVEL, lr->lr_offset / BP_GET_LSIZE(bp));
345 error = arc_read(NULL, zilog->zl_spa, bp, arc_getbuf_func, &abuf,
346 ZIO_PRIORITY_SYNC_READ, zio_flags, &aflags, &zb);
350 memcpy(wbuf, abuf->b_data, arc_buf_size(abuf));
351 arc_buf_destroy(abuf, &abuf);
358 zil_sums_init(zil_sums_t *zs)
360 wmsum_init(&zs->zil_commit_count, 0);
361 wmsum_init(&zs->zil_commit_writer_count, 0);
362 wmsum_init(&zs->zil_itx_count, 0);
363 wmsum_init(&zs->zil_itx_indirect_count, 0);
364 wmsum_init(&zs->zil_itx_indirect_bytes, 0);
365 wmsum_init(&zs->zil_itx_copied_count, 0);
366 wmsum_init(&zs->zil_itx_copied_bytes, 0);
367 wmsum_init(&zs->zil_itx_needcopy_count, 0);
368 wmsum_init(&zs->zil_itx_needcopy_bytes, 0);
369 wmsum_init(&zs->zil_itx_metaslab_normal_count, 0);
370 wmsum_init(&zs->zil_itx_metaslab_normal_bytes, 0);
371 wmsum_init(&zs->zil_itx_metaslab_slog_count, 0);
372 wmsum_init(&zs->zil_itx_metaslab_slog_bytes, 0);
376 zil_sums_fini(zil_sums_t *zs)
378 wmsum_fini(&zs->zil_commit_count);
379 wmsum_fini(&zs->zil_commit_writer_count);
380 wmsum_fini(&zs->zil_itx_count);
381 wmsum_fini(&zs->zil_itx_indirect_count);
382 wmsum_fini(&zs->zil_itx_indirect_bytes);
383 wmsum_fini(&zs->zil_itx_copied_count);
384 wmsum_fini(&zs->zil_itx_copied_bytes);
385 wmsum_fini(&zs->zil_itx_needcopy_count);
386 wmsum_fini(&zs->zil_itx_needcopy_bytes);
387 wmsum_fini(&zs->zil_itx_metaslab_normal_count);
388 wmsum_fini(&zs->zil_itx_metaslab_normal_bytes);
389 wmsum_fini(&zs->zil_itx_metaslab_slog_count);
390 wmsum_fini(&zs->zil_itx_metaslab_slog_bytes);
394 zil_kstat_values_update(zil_kstat_values_t *zs, zil_sums_t *zil_sums)
396 zs->zil_commit_count.value.ui64 =
397 wmsum_value(&zil_sums->zil_commit_count);
398 zs->zil_commit_writer_count.value.ui64 =
399 wmsum_value(&zil_sums->zil_commit_writer_count);
400 zs->zil_itx_count.value.ui64 =
401 wmsum_value(&zil_sums->zil_itx_count);
402 zs->zil_itx_indirect_count.value.ui64 =
403 wmsum_value(&zil_sums->zil_itx_indirect_count);
404 zs->zil_itx_indirect_bytes.value.ui64 =
405 wmsum_value(&zil_sums->zil_itx_indirect_bytes);
406 zs->zil_itx_copied_count.value.ui64 =
407 wmsum_value(&zil_sums->zil_itx_copied_count);
408 zs->zil_itx_copied_bytes.value.ui64 =
409 wmsum_value(&zil_sums->zil_itx_copied_bytes);
410 zs->zil_itx_needcopy_count.value.ui64 =
411 wmsum_value(&zil_sums->zil_itx_needcopy_count);
412 zs->zil_itx_needcopy_bytes.value.ui64 =
413 wmsum_value(&zil_sums->zil_itx_needcopy_bytes);
414 zs->zil_itx_metaslab_normal_count.value.ui64 =
415 wmsum_value(&zil_sums->zil_itx_metaslab_normal_count);
416 zs->zil_itx_metaslab_normal_bytes.value.ui64 =
417 wmsum_value(&zil_sums->zil_itx_metaslab_normal_bytes);
418 zs->zil_itx_metaslab_slog_count.value.ui64 =
419 wmsum_value(&zil_sums->zil_itx_metaslab_slog_count);
420 zs->zil_itx_metaslab_slog_bytes.value.ui64 =
421 wmsum_value(&zil_sums->zil_itx_metaslab_slog_bytes);
425 * Parse the intent log, and call parse_func for each valid record within.
428 zil_parse(zilog_t *zilog, zil_parse_blk_func_t *parse_blk_func,
429 zil_parse_lr_func_t *parse_lr_func, void *arg, uint64_t txg,
432 const zil_header_t *zh = zilog->zl_header;
433 boolean_t claimed = !!zh->zh_claim_txg;
434 uint64_t claim_blk_seq = claimed ? zh->zh_claim_blk_seq : UINT64_MAX;
435 uint64_t claim_lr_seq = claimed ? zh->zh_claim_lr_seq : UINT64_MAX;
436 uint64_t max_blk_seq = 0;
437 uint64_t max_lr_seq = 0;
438 uint64_t blk_count = 0;
439 uint64_t lr_count = 0;
440 blkptr_t blk, next_blk = {{{{0}}}};
445 * Old logs didn't record the maximum zh_claim_lr_seq.
447 if (!(zh->zh_flags & ZIL_CLAIM_LR_SEQ_VALID))
448 claim_lr_seq = UINT64_MAX;
451 * Starting at the block pointed to by zh_log we read the log chain.
452 * For each block in the chain we strongly check that block to
453 * ensure its validity. We stop when an invalid block is found.
454 * For each block pointer in the chain we call parse_blk_func().
455 * For each record in each valid block we call parse_lr_func().
456 * If the log has been claimed, stop if we encounter a sequence
457 * number greater than the highest claimed sequence number.
459 lrbuf = zio_buf_alloc(SPA_OLD_MAXBLOCKSIZE);
460 zil_bp_tree_init(zilog);
462 for (blk = zh->zh_log; !BP_IS_HOLE(&blk); blk = next_blk) {
463 uint64_t blk_seq = blk.blk_cksum.zc_word[ZIL_ZC_SEQ];
467 if (blk_seq > claim_blk_seq)
470 error = parse_blk_func(zilog, &blk, arg, txg);
473 ASSERT3U(max_blk_seq, <, blk_seq);
474 max_blk_seq = blk_seq;
477 if (max_lr_seq == claim_lr_seq && max_blk_seq == claim_blk_seq)
480 error = zil_read_log_block(zilog, decrypt, &blk, &next_blk,
485 for (lrp = lrbuf; lrp < end; lrp += reclen) {
486 lr_t *lr = (lr_t *)lrp;
487 reclen = lr->lrc_reclen;
488 ASSERT3U(reclen, >=, sizeof (lr_t));
489 if (lr->lrc_seq > claim_lr_seq)
492 error = parse_lr_func(zilog, lr, arg, txg);
495 ASSERT3U(max_lr_seq, <, lr->lrc_seq);
496 max_lr_seq = lr->lrc_seq;
501 zilog->zl_parse_error = error;
502 zilog->zl_parse_blk_seq = max_blk_seq;
503 zilog->zl_parse_lr_seq = max_lr_seq;
504 zilog->zl_parse_blk_count = blk_count;
505 zilog->zl_parse_lr_count = lr_count;
507 ASSERT(!claimed || !(zh->zh_flags & ZIL_CLAIM_LR_SEQ_VALID) ||
508 (max_blk_seq == claim_blk_seq && max_lr_seq == claim_lr_seq) ||
509 (decrypt && error == EIO));
511 zil_bp_tree_fini(zilog);
512 zio_buf_free(lrbuf, SPA_OLD_MAXBLOCKSIZE);
518 zil_clear_log_block(zilog_t *zilog, const blkptr_t *bp, void *tx,
522 ASSERT(!BP_IS_HOLE(bp));
525 * As we call this function from the context of a rewind to a
526 * checkpoint, each ZIL block whose txg is later than the txg
527 * that we rewind to is invalid. Thus, we return -1 so
528 * zil_parse() doesn't attempt to read it.
530 if (bp->blk_birth >= first_txg)
533 if (zil_bp_tree_add(zilog, bp) != 0)
536 zio_free(zilog->zl_spa, first_txg, bp);
541 zil_noop_log_record(zilog_t *zilog, const lr_t *lrc, void *tx,
544 (void) zilog, (void) lrc, (void) tx, (void) first_txg;
549 zil_claim_log_block(zilog_t *zilog, const blkptr_t *bp, void *tx,
553 * Claim log block if not already committed and not already claimed.
554 * If tx == NULL, just verify that the block is claimable.
556 if (BP_IS_HOLE(bp) || bp->blk_birth < first_txg ||
557 zil_bp_tree_add(zilog, bp) != 0)
560 return (zio_wait(zio_claim(NULL, zilog->zl_spa,
561 tx == NULL ? 0 : first_txg, bp, spa_claim_notify, NULL,
562 ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE | ZIO_FLAG_SCRUB)));
566 zil_claim_log_record(zilog_t *zilog, const lr_t *lrc, void *tx,
569 lr_write_t *lr = (lr_write_t *)lrc;
572 if (lrc->lrc_txtype != TX_WRITE)
576 * If the block is not readable, don't claim it. This can happen
577 * in normal operation when a log block is written to disk before
578 * some of the dmu_sync() blocks it points to. In this case, the
579 * transaction cannot have been committed to anyone (we would have
580 * waited for all writes to be stable first), so it is semantically
581 * correct to declare this the end of the log.
583 if (lr->lr_blkptr.blk_birth >= first_txg) {
584 error = zil_read_log_data(zilog, lr, NULL);
589 return (zil_claim_log_block(zilog, &lr->lr_blkptr, tx, first_txg));
593 zil_free_log_block(zilog_t *zilog, const blkptr_t *bp, void *tx,
598 zio_free(zilog->zl_spa, dmu_tx_get_txg(tx), bp);
604 zil_free_log_record(zilog_t *zilog, const lr_t *lrc, void *tx,
607 lr_write_t *lr = (lr_write_t *)lrc;
608 blkptr_t *bp = &lr->lr_blkptr;
611 * If we previously claimed it, we need to free it.
613 if (claim_txg != 0 && lrc->lrc_txtype == TX_WRITE &&
614 bp->blk_birth >= claim_txg && zil_bp_tree_add(zilog, bp) == 0 &&
616 zio_free(zilog->zl_spa, dmu_tx_get_txg(tx), bp);
622 zil_lwb_vdev_compare(const void *x1, const void *x2)
624 const uint64_t v1 = ((zil_vdev_node_t *)x1)->zv_vdev;
625 const uint64_t v2 = ((zil_vdev_node_t *)x2)->zv_vdev;
627 return (TREE_CMP(v1, v2));
631 zil_alloc_lwb(zilog_t *zilog, blkptr_t *bp, boolean_t slog, uint64_t txg,
636 lwb = kmem_cache_alloc(zil_lwb_cache, KM_SLEEP);
637 lwb->lwb_zilog = zilog;
639 lwb->lwb_fastwrite = fastwrite;
640 lwb->lwb_slog = slog;
641 lwb->lwb_state = LWB_STATE_CLOSED;
642 lwb->lwb_buf = zio_buf_alloc(BP_GET_LSIZE(bp));
643 lwb->lwb_max_txg = txg;
644 lwb->lwb_write_zio = NULL;
645 lwb->lwb_root_zio = NULL;
646 lwb->lwb_issued_timestamp = 0;
647 lwb->lwb_issued_txg = 0;
648 if (BP_GET_CHECKSUM(bp) == ZIO_CHECKSUM_ZILOG2) {
649 lwb->lwb_nused = sizeof (zil_chain_t);
650 lwb->lwb_sz = BP_GET_LSIZE(bp);
653 lwb->lwb_sz = BP_GET_LSIZE(bp) - sizeof (zil_chain_t);
656 mutex_enter(&zilog->zl_lock);
657 list_insert_tail(&zilog->zl_lwb_list, lwb);
658 mutex_exit(&zilog->zl_lock);
660 ASSERT(!MUTEX_HELD(&lwb->lwb_vdev_lock));
661 ASSERT(avl_is_empty(&lwb->lwb_vdev_tree));
662 VERIFY(list_is_empty(&lwb->lwb_waiters));
663 VERIFY(list_is_empty(&lwb->lwb_itxs));
669 zil_free_lwb(zilog_t *zilog, lwb_t *lwb)
671 ASSERT(MUTEX_HELD(&zilog->zl_lock));
672 ASSERT(!MUTEX_HELD(&lwb->lwb_vdev_lock));
673 VERIFY(list_is_empty(&lwb->lwb_waiters));
674 VERIFY(list_is_empty(&lwb->lwb_itxs));
675 ASSERT(avl_is_empty(&lwb->lwb_vdev_tree));
676 ASSERT3P(lwb->lwb_write_zio, ==, NULL);
677 ASSERT3P(lwb->lwb_root_zio, ==, NULL);
678 ASSERT3U(lwb->lwb_max_txg, <=, spa_syncing_txg(zilog->zl_spa));
679 ASSERT(lwb->lwb_state == LWB_STATE_CLOSED ||
680 lwb->lwb_state == LWB_STATE_FLUSH_DONE);
683 * Clear the zilog's field to indicate this lwb is no longer
684 * valid, and prevent use-after-free errors.
686 if (zilog->zl_last_lwb_opened == lwb)
687 zilog->zl_last_lwb_opened = NULL;
689 kmem_cache_free(zil_lwb_cache, lwb);
693 * Called when we create in-memory log transactions so that we know
694 * to cleanup the itxs at the end of spa_sync().
697 zilog_dirty(zilog_t *zilog, uint64_t txg)
699 dsl_pool_t *dp = zilog->zl_dmu_pool;
700 dsl_dataset_t *ds = dmu_objset_ds(zilog->zl_os);
702 ASSERT(spa_writeable(zilog->zl_spa));
704 if (ds->ds_is_snapshot)
705 panic("dirtying snapshot!");
707 if (txg_list_add(&dp->dp_dirty_zilogs, zilog, txg)) {
708 /* up the hold count until we can be written out */
709 dmu_buf_add_ref(ds->ds_dbuf, zilog);
711 zilog->zl_dirty_max_txg = MAX(txg, zilog->zl_dirty_max_txg);
716 * Determine if the zil is dirty in the specified txg. Callers wanting to
717 * ensure that the dirty state does not change must hold the itxg_lock for
718 * the specified txg. Holding the lock will ensure that the zil cannot be
719 * dirtied (zil_itx_assign) or cleaned (zil_clean) while we check its current
722 static boolean_t __maybe_unused
723 zilog_is_dirty_in_txg(zilog_t *zilog, uint64_t txg)
725 dsl_pool_t *dp = zilog->zl_dmu_pool;
727 if (txg_list_member(&dp->dp_dirty_zilogs, zilog, txg & TXG_MASK))
733 * Determine if the zil is dirty. The zil is considered dirty if it has
734 * any pending itx records that have not been cleaned by zil_clean().
737 zilog_is_dirty(zilog_t *zilog)
739 dsl_pool_t *dp = zilog->zl_dmu_pool;
741 for (int t = 0; t < TXG_SIZE; t++) {
742 if (txg_list_member(&dp->dp_dirty_zilogs, zilog, t))
749 * Its called in zil_commit context (zil_process_commit_list()/zil_create()).
750 * It activates SPA_FEATURE_ZILSAXATTR feature, if its enabled.
751 * Check dsl_dataset_feature_is_active to avoid txg_wait_synced() on every
755 zil_commit_activate_saxattr_feature(zilog_t *zilog)
757 dsl_dataset_t *ds = dmu_objset_ds(zilog->zl_os);
761 if (spa_feature_is_enabled(zilog->zl_spa,
762 SPA_FEATURE_ZILSAXATTR) &&
763 dmu_objset_type(zilog->zl_os) != DMU_OST_ZVOL &&
764 !dsl_dataset_feature_is_active(ds,
765 SPA_FEATURE_ZILSAXATTR)) {
766 tx = dmu_tx_create(zilog->zl_os);
767 VERIFY0(dmu_tx_assign(tx, TXG_WAIT));
768 dsl_dataset_dirty(ds, tx);
769 txg = dmu_tx_get_txg(tx);
771 mutex_enter(&ds->ds_lock);
772 ds->ds_feature_activation[SPA_FEATURE_ZILSAXATTR] =
774 mutex_exit(&ds->ds_lock);
776 txg_wait_synced(zilog->zl_dmu_pool, txg);
781 * Create an on-disk intent log.
784 zil_create(zilog_t *zilog)
786 const zil_header_t *zh = zilog->zl_header;
792 boolean_t fastwrite = FALSE;
793 boolean_t slog = FALSE;
794 dsl_dataset_t *ds = dmu_objset_ds(zilog->zl_os);
798 * Wait for any previous destroy to complete.
800 txg_wait_synced(zilog->zl_dmu_pool, zilog->zl_destroy_txg);
802 ASSERT(zh->zh_claim_txg == 0);
803 ASSERT(zh->zh_replay_seq == 0);
808 * Allocate an initial log block if:
809 * - there isn't one already
810 * - the existing block is the wrong endianness
812 if (BP_IS_HOLE(&blk) || BP_SHOULD_BYTESWAP(&blk)) {
813 tx = dmu_tx_create(zilog->zl_os);
814 VERIFY0(dmu_tx_assign(tx, TXG_WAIT));
815 dsl_dataset_dirty(dmu_objset_ds(zilog->zl_os), tx);
816 txg = dmu_tx_get_txg(tx);
818 if (!BP_IS_HOLE(&blk)) {
819 zio_free(zilog->zl_spa, txg, &blk);
823 error = zio_alloc_zil(zilog->zl_spa, zilog->zl_os, txg, &blk,
824 ZIL_MIN_BLKSZ, &slog);
828 zil_init_log_chain(zilog, &blk);
832 * Allocate a log write block (lwb) for the first log block.
835 lwb = zil_alloc_lwb(zilog, &blk, slog, txg, fastwrite);
838 * If we just allocated the first log block, commit our transaction
839 * and wait for zil_sync() to stuff the block pointer into zh_log.
840 * (zh is part of the MOS, so we cannot modify it in open context.)
844 * If "zilsaxattr" feature is enabled on zpool, then activate
845 * it now when we're creating the ZIL chain. We can't wait with
846 * this until we write the first xattr log record because we
847 * need to wait for the feature activation to sync out.
849 if (spa_feature_is_enabled(zilog->zl_spa,
850 SPA_FEATURE_ZILSAXATTR) && dmu_objset_type(zilog->zl_os) !=
852 mutex_enter(&ds->ds_lock);
853 ds->ds_feature_activation[SPA_FEATURE_ZILSAXATTR] =
855 mutex_exit(&ds->ds_lock);
859 txg_wait_synced(zilog->zl_dmu_pool, txg);
862 * This branch covers the case where we enable the feature on a
863 * zpool that has existing ZIL headers.
865 zil_commit_activate_saxattr_feature(zilog);
867 IMPLY(spa_feature_is_enabled(zilog->zl_spa, SPA_FEATURE_ZILSAXATTR) &&
868 dmu_objset_type(zilog->zl_os) != DMU_OST_ZVOL,
869 dsl_dataset_feature_is_active(ds, SPA_FEATURE_ZILSAXATTR));
871 ASSERT(error != 0 || memcmp(&blk, &zh->zh_log, sizeof (blk)) == 0);
872 IMPLY(error == 0, lwb != NULL);
878 * In one tx, free all log blocks and clear the log header. If keep_first
879 * is set, then we're replaying a log with no content. We want to keep the
880 * first block, however, so that the first synchronous transaction doesn't
881 * require a txg_wait_synced() in zil_create(). We don't need to
882 * txg_wait_synced() here either when keep_first is set, because both
883 * zil_create() and zil_destroy() will wait for any in-progress destroys
887 zil_destroy(zilog_t *zilog, boolean_t keep_first)
889 const zil_header_t *zh = zilog->zl_header;
895 * Wait for any previous destroy to complete.
897 txg_wait_synced(zilog->zl_dmu_pool, zilog->zl_destroy_txg);
899 zilog->zl_old_header = *zh; /* debugging aid */
901 if (BP_IS_HOLE(&zh->zh_log))
904 tx = dmu_tx_create(zilog->zl_os);
905 VERIFY0(dmu_tx_assign(tx, TXG_WAIT));
906 dsl_dataset_dirty(dmu_objset_ds(zilog->zl_os), tx);
907 txg = dmu_tx_get_txg(tx);
909 mutex_enter(&zilog->zl_lock);
911 ASSERT3U(zilog->zl_destroy_txg, <, txg);
912 zilog->zl_destroy_txg = txg;
913 zilog->zl_keep_first = keep_first;
915 if (!list_is_empty(&zilog->zl_lwb_list)) {
916 ASSERT(zh->zh_claim_txg == 0);
918 while ((lwb = list_head(&zilog->zl_lwb_list)) != NULL) {
919 if (lwb->lwb_fastwrite)
920 metaslab_fastwrite_unmark(zilog->zl_spa,
923 list_remove(&zilog->zl_lwb_list, lwb);
924 if (lwb->lwb_buf != NULL)
925 zio_buf_free(lwb->lwb_buf, lwb->lwb_sz);
926 zio_free(zilog->zl_spa, txg, &lwb->lwb_blk);
927 zil_free_lwb(zilog, lwb);
929 } else if (!keep_first) {
930 zil_destroy_sync(zilog, tx);
932 mutex_exit(&zilog->zl_lock);
938 zil_destroy_sync(zilog_t *zilog, dmu_tx_t *tx)
940 ASSERT(list_is_empty(&zilog->zl_lwb_list));
941 (void) zil_parse(zilog, zil_free_log_block,
942 zil_free_log_record, tx, zilog->zl_header->zh_claim_txg, B_FALSE);
946 zil_claim(dsl_pool_t *dp, dsl_dataset_t *ds, void *txarg)
948 dmu_tx_t *tx = txarg;
955 error = dmu_objset_own_obj(dp, ds->ds_object,
956 DMU_OST_ANY, B_FALSE, B_FALSE, FTAG, &os);
959 * EBUSY indicates that the objset is inconsistent, in which
960 * case it can not have a ZIL.
962 if (error != EBUSY) {
963 cmn_err(CE_WARN, "can't open objset for %llu, error %u",
964 (unsigned long long)ds->ds_object, error);
970 zilog = dmu_objset_zil(os);
971 zh = zil_header_in_syncing_context(zilog);
972 ASSERT3U(tx->tx_txg, ==, spa_first_txg(zilog->zl_spa));
973 first_txg = spa_min_claim_txg(zilog->zl_spa);
976 * If the spa_log_state is not set to be cleared, check whether
977 * the current uberblock is a checkpoint one and if the current
978 * header has been claimed before moving on.
980 * If the current uberblock is a checkpointed uberblock then
981 * one of the following scenarios took place:
983 * 1] We are currently rewinding to the checkpoint of the pool.
984 * 2] We crashed in the middle of a checkpoint rewind but we
985 * did manage to write the checkpointed uberblock to the
986 * vdev labels, so when we tried to import the pool again
987 * the checkpointed uberblock was selected from the import
990 * In both cases we want to zero out all the ZIL blocks, except
991 * the ones that have been claimed at the time of the checkpoint
992 * (their zh_claim_txg != 0). The reason is that these blocks
993 * may be corrupted since we may have reused their locations on
994 * disk after we took the checkpoint.
996 * We could try to set spa_log_state to SPA_LOG_CLEAR earlier
997 * when we first figure out whether the current uberblock is
998 * checkpointed or not. Unfortunately, that would discard all
999 * the logs, including the ones that are claimed, and we would
1002 if (spa_get_log_state(zilog->zl_spa) == SPA_LOG_CLEAR ||
1003 (zilog->zl_spa->spa_uberblock.ub_checkpoint_txg != 0 &&
1004 zh->zh_claim_txg == 0)) {
1005 if (!BP_IS_HOLE(&zh->zh_log)) {
1006 (void) zil_parse(zilog, zil_clear_log_block,
1007 zil_noop_log_record, tx, first_txg, B_FALSE);
1009 BP_ZERO(&zh->zh_log);
1010 if (os->os_encrypted)
1011 os->os_next_write_raw[tx->tx_txg & TXG_MASK] = B_TRUE;
1012 dsl_dataset_dirty(dmu_objset_ds(os), tx);
1013 dmu_objset_disown(os, B_FALSE, FTAG);
1018 * If we are not rewinding and opening the pool normally, then
1019 * the min_claim_txg should be equal to the first txg of the pool.
1021 ASSERT3U(first_txg, ==, spa_first_txg(zilog->zl_spa));
1024 * Claim all log blocks if we haven't already done so, and remember
1025 * the highest claimed sequence number. This ensures that if we can
1026 * read only part of the log now (e.g. due to a missing device),
1027 * but we can read the entire log later, we will not try to replay
1028 * or destroy beyond the last block we successfully claimed.
1030 ASSERT3U(zh->zh_claim_txg, <=, first_txg);
1031 if (zh->zh_claim_txg == 0 && !BP_IS_HOLE(&zh->zh_log)) {
1032 (void) zil_parse(zilog, zil_claim_log_block,
1033 zil_claim_log_record, tx, first_txg, B_FALSE);
1034 zh->zh_claim_txg = first_txg;
1035 zh->zh_claim_blk_seq = zilog->zl_parse_blk_seq;
1036 zh->zh_claim_lr_seq = zilog->zl_parse_lr_seq;
1037 if (zilog->zl_parse_lr_count || zilog->zl_parse_blk_count > 1)
1038 zh->zh_flags |= ZIL_REPLAY_NEEDED;
1039 zh->zh_flags |= ZIL_CLAIM_LR_SEQ_VALID;
1040 if (os->os_encrypted)
1041 os->os_next_write_raw[tx->tx_txg & TXG_MASK] = B_TRUE;
1042 dsl_dataset_dirty(dmu_objset_ds(os), tx);
1045 ASSERT3U(first_txg, ==, (spa_last_synced_txg(zilog->zl_spa) + 1));
1046 dmu_objset_disown(os, B_FALSE, FTAG);
1051 * Check the log by walking the log chain.
1052 * Checksum errors are ok as they indicate the end of the chain.
1053 * Any other error (no device or read failure) returns an error.
1056 zil_check_log_chain(dsl_pool_t *dp, dsl_dataset_t *ds, void *tx)
1066 error = dmu_objset_from_ds(ds, &os);
1068 cmn_err(CE_WARN, "can't open objset %llu, error %d",
1069 (unsigned long long)ds->ds_object, error);
1073 zilog = dmu_objset_zil(os);
1074 bp = (blkptr_t *)&zilog->zl_header->zh_log;
1076 if (!BP_IS_HOLE(bp)) {
1078 boolean_t valid = B_TRUE;
1081 * Check the first block and determine if it's on a log device
1082 * which may have been removed or faulted prior to loading this
1083 * pool. If so, there's no point in checking the rest of the
1084 * log as its content should have already been synced to the
1087 spa_config_enter(os->os_spa, SCL_STATE, FTAG, RW_READER);
1088 vd = vdev_lookup_top(os->os_spa, DVA_GET_VDEV(&bp->blk_dva[0]));
1089 if (vd->vdev_islog && vdev_is_dead(vd))
1090 valid = vdev_log_state_valid(vd);
1091 spa_config_exit(os->os_spa, SCL_STATE, FTAG);
1097 * Check whether the current uberblock is checkpointed (e.g.
1098 * we are rewinding) and whether the current header has been
1099 * claimed or not. If it hasn't then skip verifying it. We
1100 * do this because its ZIL blocks may be part of the pool's
1101 * state before the rewind, which is no longer valid.
1103 zil_header_t *zh = zil_header_in_syncing_context(zilog);
1104 if (zilog->zl_spa->spa_uberblock.ub_checkpoint_txg != 0 &&
1105 zh->zh_claim_txg == 0)
1110 * Because tx == NULL, zil_claim_log_block() will not actually claim
1111 * any blocks, but just determine whether it is possible to do so.
1112 * In addition to checking the log chain, zil_claim_log_block()
1113 * will invoke zio_claim() with a done func of spa_claim_notify(),
1114 * which will update spa_max_claim_txg. See spa_load() for details.
1116 error = zil_parse(zilog, zil_claim_log_block, zil_claim_log_record, tx,
1117 zilog->zl_header->zh_claim_txg ? -1ULL :
1118 spa_min_claim_txg(os->os_spa), B_FALSE);
1120 return ((error == ECKSUM || error == ENOENT) ? 0 : error);
1124 * When an itx is "skipped", this function is used to properly mark the
1125 * waiter as "done, and signal any thread(s) waiting on it. An itx can
1126 * be skipped (and not committed to an lwb) for a variety of reasons,
1127 * one of them being that the itx was committed via spa_sync(), prior to
1128 * it being committed to an lwb; this can happen if a thread calling
1129 * zil_commit() is racing with spa_sync().
1132 zil_commit_waiter_skip(zil_commit_waiter_t *zcw)
1134 mutex_enter(&zcw->zcw_lock);
1135 ASSERT3B(zcw->zcw_done, ==, B_FALSE);
1136 zcw->zcw_done = B_TRUE;
1137 cv_broadcast(&zcw->zcw_cv);
1138 mutex_exit(&zcw->zcw_lock);
1142 * This function is used when the given waiter is to be linked into an
1143 * lwb's "lwb_waiter" list; i.e. when the itx is committed to the lwb.
1144 * At this point, the waiter will no longer be referenced by the itx,
1145 * and instead, will be referenced by the lwb.
1148 zil_commit_waiter_link_lwb(zil_commit_waiter_t *zcw, lwb_t *lwb)
1151 * The lwb_waiters field of the lwb is protected by the zilog's
1152 * zl_lock, thus it must be held when calling this function.
1154 ASSERT(MUTEX_HELD(&lwb->lwb_zilog->zl_lock));
1156 mutex_enter(&zcw->zcw_lock);
1157 ASSERT(!list_link_active(&zcw->zcw_node));
1158 ASSERT3P(zcw->zcw_lwb, ==, NULL);
1159 ASSERT3P(lwb, !=, NULL);
1160 ASSERT(lwb->lwb_state == LWB_STATE_OPENED ||
1161 lwb->lwb_state == LWB_STATE_ISSUED ||
1162 lwb->lwb_state == LWB_STATE_WRITE_DONE);
1164 list_insert_tail(&lwb->lwb_waiters, zcw);
1166 mutex_exit(&zcw->zcw_lock);
1170 * This function is used when zio_alloc_zil() fails to allocate a ZIL
1171 * block, and the given waiter must be linked to the "nolwb waiters"
1172 * list inside of zil_process_commit_list().
1175 zil_commit_waiter_link_nolwb(zil_commit_waiter_t *zcw, list_t *nolwb)
1177 mutex_enter(&zcw->zcw_lock);
1178 ASSERT(!list_link_active(&zcw->zcw_node));
1179 ASSERT3P(zcw->zcw_lwb, ==, NULL);
1180 list_insert_tail(nolwb, zcw);
1181 mutex_exit(&zcw->zcw_lock);
1185 zil_lwb_add_block(lwb_t *lwb, const blkptr_t *bp)
1187 avl_tree_t *t = &lwb->lwb_vdev_tree;
1189 zil_vdev_node_t *zv, zvsearch;
1190 int ndvas = BP_GET_NDVAS(bp);
1193 if (zil_nocacheflush)
1196 mutex_enter(&lwb->lwb_vdev_lock);
1197 for (i = 0; i < ndvas; i++) {
1198 zvsearch.zv_vdev = DVA_GET_VDEV(&bp->blk_dva[i]);
1199 if (avl_find(t, &zvsearch, &where) == NULL) {
1200 zv = kmem_alloc(sizeof (*zv), KM_SLEEP);
1201 zv->zv_vdev = zvsearch.zv_vdev;
1202 avl_insert(t, zv, where);
1205 mutex_exit(&lwb->lwb_vdev_lock);
1209 zil_lwb_flush_defer(lwb_t *lwb, lwb_t *nlwb)
1211 avl_tree_t *src = &lwb->lwb_vdev_tree;
1212 avl_tree_t *dst = &nlwb->lwb_vdev_tree;
1213 void *cookie = NULL;
1214 zil_vdev_node_t *zv;
1216 ASSERT3S(lwb->lwb_state, ==, LWB_STATE_WRITE_DONE);
1217 ASSERT3S(nlwb->lwb_state, !=, LWB_STATE_WRITE_DONE);
1218 ASSERT3S(nlwb->lwb_state, !=, LWB_STATE_FLUSH_DONE);
1221 * While 'lwb' is at a point in its lifetime where lwb_vdev_tree does
1222 * not need the protection of lwb_vdev_lock (it will only be modified
1223 * while holding zilog->zl_lock) as its writes and those of its
1224 * children have all completed. The younger 'nlwb' may be waiting on
1225 * future writes to additional vdevs.
1227 mutex_enter(&nlwb->lwb_vdev_lock);
1229 * Tear down the 'lwb' vdev tree, ensuring that entries which do not
1230 * exist in 'nlwb' are moved to it, freeing any would-be duplicates.
1232 while ((zv = avl_destroy_nodes(src, &cookie)) != NULL) {
1235 if (avl_find(dst, zv, &where) == NULL) {
1236 avl_insert(dst, zv, where);
1238 kmem_free(zv, sizeof (*zv));
1241 mutex_exit(&nlwb->lwb_vdev_lock);
1245 zil_lwb_add_txg(lwb_t *lwb, uint64_t txg)
1247 lwb->lwb_max_txg = MAX(lwb->lwb_max_txg, txg);
1251 * This function is a called after all vdevs associated with a given lwb
1252 * write have completed their DKIOCFLUSHWRITECACHE command; or as soon
1253 * as the lwb write completes, if "zil_nocacheflush" is set. Further,
1254 * all "previous" lwb's will have completed before this function is
1255 * called; i.e. this function is called for all previous lwbs before
1256 * it's called for "this" lwb (enforced via zio the dependencies
1257 * configured in zil_lwb_set_zio_dependency()).
1259 * The intention is for this function to be called as soon as the
1260 * contents of an lwb are considered "stable" on disk, and will survive
1261 * any sudden loss of power. At this point, any threads waiting for the
1262 * lwb to reach this state are signalled, and the "waiter" structures
1263 * are marked "done".
1266 zil_lwb_flush_vdevs_done(zio_t *zio)
1268 lwb_t *lwb = zio->io_private;
1269 zilog_t *zilog = lwb->lwb_zilog;
1270 zil_commit_waiter_t *zcw;
1274 spa_config_exit(zilog->zl_spa, SCL_STATE, lwb);
1276 zio_buf_free(lwb->lwb_buf, lwb->lwb_sz);
1278 mutex_enter(&zilog->zl_lock);
1281 * If we have had an allocation failure and the txg is
1282 * waiting to sync then we want zil_sync() to remove the lwb so
1283 * that it's not picked up as the next new one in
1284 * zil_process_commit_list(). zil_sync() will only remove the
1285 * lwb if lwb_buf is null.
1287 lwb->lwb_buf = NULL;
1289 ASSERT3U(lwb->lwb_issued_timestamp, >, 0);
1290 zilog->zl_last_lwb_latency = gethrtime() - lwb->lwb_issued_timestamp;
1292 lwb->lwb_root_zio = NULL;
1294 ASSERT3S(lwb->lwb_state, ==, LWB_STATE_WRITE_DONE);
1295 lwb->lwb_state = LWB_STATE_FLUSH_DONE;
1297 if (zilog->zl_last_lwb_opened == lwb) {
1299 * Remember the highest committed log sequence number
1300 * for ztest. We only update this value when all the log
1301 * writes succeeded, because ztest wants to ASSERT that
1302 * it got the whole log chain.
1304 zilog->zl_commit_lr_seq = zilog->zl_lr_seq;
1307 while ((itx = list_head(&lwb->lwb_itxs)) != NULL) {
1308 list_remove(&lwb->lwb_itxs, itx);
1309 zil_itx_destroy(itx);
1312 while ((zcw = list_head(&lwb->lwb_waiters)) != NULL) {
1313 mutex_enter(&zcw->zcw_lock);
1315 ASSERT(list_link_active(&zcw->zcw_node));
1316 list_remove(&lwb->lwb_waiters, zcw);
1318 ASSERT3P(zcw->zcw_lwb, ==, lwb);
1319 zcw->zcw_lwb = NULL;
1321 * We expect any ZIO errors from child ZIOs to have been
1322 * propagated "up" to this specific LWB's root ZIO, in
1323 * order for this error handling to work correctly. This
1324 * includes ZIO errors from either this LWB's write or
1325 * flush, as well as any errors from other dependent LWBs
1326 * (e.g. a root LWB ZIO that might be a child of this LWB).
1328 * With that said, it's important to note that LWB flush
1329 * errors are not propagated up to the LWB root ZIO.
1330 * This is incorrect behavior, and results in VDEV flush
1331 * errors not being handled correctly here. See the
1332 * comment above the call to "zio_flush" for details.
1335 zcw->zcw_zio_error = zio->io_error;
1337 ASSERT3B(zcw->zcw_done, ==, B_FALSE);
1338 zcw->zcw_done = B_TRUE;
1339 cv_broadcast(&zcw->zcw_cv);
1341 mutex_exit(&zcw->zcw_lock);
1344 mutex_exit(&zilog->zl_lock);
1346 mutex_enter(&zilog->zl_lwb_io_lock);
1347 txg = lwb->lwb_issued_txg;
1348 ASSERT3U(zilog->zl_lwb_inflight[txg & TXG_MASK], >, 0);
1349 zilog->zl_lwb_inflight[txg & TXG_MASK]--;
1350 if (zilog->zl_lwb_inflight[txg & TXG_MASK] == 0)
1351 cv_broadcast(&zilog->zl_lwb_io_cv);
1352 mutex_exit(&zilog->zl_lwb_io_lock);
1356 * Wait for the completion of all issued write/flush of that txg provided.
1357 * It guarantees zil_lwb_flush_vdevs_done() is called and returned.
1360 zil_lwb_flush_wait_all(zilog_t *zilog, uint64_t txg)
1362 ASSERT3U(txg, ==, spa_syncing_txg(zilog->zl_spa));
1364 mutex_enter(&zilog->zl_lwb_io_lock);
1365 while (zilog->zl_lwb_inflight[txg & TXG_MASK] > 0)
1366 cv_wait(&zilog->zl_lwb_io_cv, &zilog->zl_lwb_io_lock);
1367 mutex_exit(&zilog->zl_lwb_io_lock);
1370 mutex_enter(&zilog->zl_lock);
1371 mutex_enter(&zilog->zl_lwb_io_lock);
1372 lwb_t *lwb = list_head(&zilog->zl_lwb_list);
1373 while (lwb != NULL && lwb->lwb_max_txg <= txg) {
1374 if (lwb->lwb_issued_txg <= txg) {
1375 ASSERT(lwb->lwb_state != LWB_STATE_ISSUED);
1376 ASSERT(lwb->lwb_state != LWB_STATE_WRITE_DONE);
1377 IMPLY(lwb->lwb_issued_txg > 0,
1378 lwb->lwb_state == LWB_STATE_FLUSH_DONE);
1380 IMPLY(lwb->lwb_state == LWB_STATE_FLUSH_DONE,
1381 lwb->lwb_buf == NULL);
1382 lwb = list_next(&zilog->zl_lwb_list, lwb);
1384 mutex_exit(&zilog->zl_lwb_io_lock);
1385 mutex_exit(&zilog->zl_lock);
1390 * This is called when an lwb's write zio completes. The callback's
1391 * purpose is to issue the DKIOCFLUSHWRITECACHE commands for the vdevs
1392 * in the lwb's lwb_vdev_tree. The tree will contain the vdevs involved
1393 * in writing out this specific lwb's data, and in the case that cache
1394 * flushes have been deferred, vdevs involved in writing the data for
1395 * previous lwbs. The writes corresponding to all the vdevs in the
1396 * lwb_vdev_tree will have completed by the time this is called, due to
1397 * the zio dependencies configured in zil_lwb_set_zio_dependency(),
1398 * which takes deferred flushes into account. The lwb will be "done"
1399 * once zil_lwb_flush_vdevs_done() is called, which occurs in the zio
1400 * completion callback for the lwb's root zio.
1403 zil_lwb_write_done(zio_t *zio)
1405 lwb_t *lwb = zio->io_private;
1406 spa_t *spa = zio->io_spa;
1407 zilog_t *zilog = lwb->lwb_zilog;
1408 avl_tree_t *t = &lwb->lwb_vdev_tree;
1409 void *cookie = NULL;
1410 zil_vdev_node_t *zv;
1413 ASSERT3S(spa_config_held(spa, SCL_STATE, RW_READER), !=, 0);
1415 ASSERT(BP_GET_COMPRESS(zio->io_bp) == ZIO_COMPRESS_OFF);
1416 ASSERT(BP_GET_TYPE(zio->io_bp) == DMU_OT_INTENT_LOG);
1417 ASSERT(BP_GET_LEVEL(zio->io_bp) == 0);
1418 ASSERT(BP_GET_BYTEORDER(zio->io_bp) == ZFS_HOST_BYTEORDER);
1419 ASSERT(!BP_IS_GANG(zio->io_bp));
1420 ASSERT(!BP_IS_HOLE(zio->io_bp));
1421 ASSERT(BP_GET_FILL(zio->io_bp) == 0);
1423 abd_free(zio->io_abd);
1425 mutex_enter(&zilog->zl_lock);
1426 ASSERT3S(lwb->lwb_state, ==, LWB_STATE_ISSUED);
1427 lwb->lwb_state = LWB_STATE_WRITE_DONE;
1428 lwb->lwb_write_zio = NULL;
1429 lwb->lwb_fastwrite = FALSE;
1430 nlwb = list_next(&zilog->zl_lwb_list, lwb);
1431 mutex_exit(&zilog->zl_lock);
1433 if (avl_numnodes(t) == 0)
1437 * If there was an IO error, we're not going to call zio_flush()
1438 * on these vdevs, so we simply empty the tree and free the
1439 * nodes. We avoid calling zio_flush() since there isn't any
1440 * good reason for doing so, after the lwb block failed to be
1443 * Additionally, we don't perform any further error handling at
1444 * this point (e.g. setting "zcw_zio_error" appropriately), as
1445 * we expect that to occur in "zil_lwb_flush_vdevs_done" (thus,
1446 * we expect any error seen here, to have been propagated to
1449 if (zio->io_error != 0) {
1450 while ((zv = avl_destroy_nodes(t, &cookie)) != NULL)
1451 kmem_free(zv, sizeof (*zv));
1456 * If this lwb does not have any threads waiting for it to
1457 * complete, we want to defer issuing the DKIOCFLUSHWRITECACHE
1458 * command to the vdevs written to by "this" lwb, and instead
1459 * rely on the "next" lwb to handle the DKIOCFLUSHWRITECACHE
1460 * command for those vdevs. Thus, we merge the vdev tree of
1461 * "this" lwb with the vdev tree of the "next" lwb in the list,
1462 * and assume the "next" lwb will handle flushing the vdevs (or
1463 * deferring the flush(s) again).
1465 * This is a useful performance optimization, especially for
1466 * workloads with lots of async write activity and few sync
1467 * write and/or fsync activity, as it has the potential to
1468 * coalesce multiple flush commands to a vdev into one.
1470 if (list_head(&lwb->lwb_waiters) == NULL && nlwb != NULL) {
1471 zil_lwb_flush_defer(lwb, nlwb);
1472 ASSERT(avl_is_empty(&lwb->lwb_vdev_tree));
1476 while ((zv = avl_destroy_nodes(t, &cookie)) != NULL) {
1477 vdev_t *vd = vdev_lookup_top(spa, zv->zv_vdev);
1480 * The "ZIO_FLAG_DONT_PROPAGATE" is currently
1481 * always used within "zio_flush". This means,
1482 * any errors when flushing the vdev(s), will
1483 * (unfortunately) not be handled correctly,
1484 * since these "zio_flush" errors will not be
1485 * propagated up to "zil_lwb_flush_vdevs_done".
1487 zio_flush(lwb->lwb_root_zio, vd);
1489 kmem_free(zv, sizeof (*zv));
1494 zil_lwb_set_zio_dependency(zilog_t *zilog, lwb_t *lwb)
1496 lwb_t *last_lwb_opened = zilog->zl_last_lwb_opened;
1498 ASSERT(MUTEX_HELD(&zilog->zl_issuer_lock));
1499 ASSERT(MUTEX_HELD(&zilog->zl_lock));
1502 * The zilog's "zl_last_lwb_opened" field is used to build the
1503 * lwb/zio dependency chain, which is used to preserve the
1504 * ordering of lwb completions that is required by the semantics
1505 * of the ZIL. Each new lwb zio becomes a parent of the
1506 * "previous" lwb zio, such that the new lwb's zio cannot
1507 * complete until the "previous" lwb's zio completes.
1509 * This is required by the semantics of zil_commit(); the commit
1510 * waiters attached to the lwbs will be woken in the lwb zio's
1511 * completion callback, so this zio dependency graph ensures the
1512 * waiters are woken in the correct order (the same order the
1513 * lwbs were created).
1515 if (last_lwb_opened != NULL &&
1516 last_lwb_opened->lwb_state != LWB_STATE_FLUSH_DONE) {
1517 ASSERT(last_lwb_opened->lwb_state == LWB_STATE_OPENED ||
1518 last_lwb_opened->lwb_state == LWB_STATE_ISSUED ||
1519 last_lwb_opened->lwb_state == LWB_STATE_WRITE_DONE);
1521 ASSERT3P(last_lwb_opened->lwb_root_zio, !=, NULL);
1522 zio_add_child(lwb->lwb_root_zio,
1523 last_lwb_opened->lwb_root_zio);
1526 * If the previous lwb's write hasn't already completed,
1527 * we also want to order the completion of the lwb write
1528 * zios (above, we only order the completion of the lwb
1529 * root zios). This is required because of how we can
1530 * defer the DKIOCFLUSHWRITECACHE commands for each lwb.
1532 * When the DKIOCFLUSHWRITECACHE commands are deferred,
1533 * the previous lwb will rely on this lwb to flush the
1534 * vdevs written to by that previous lwb. Thus, we need
1535 * to ensure this lwb doesn't issue the flush until
1536 * after the previous lwb's write completes. We ensure
1537 * this ordering by setting the zio parent/child
1538 * relationship here.
1540 * Without this relationship on the lwb's write zio,
1541 * it's possible for this lwb's write to complete prior
1542 * to the previous lwb's write completing; and thus, the
1543 * vdevs for the previous lwb would be flushed prior to
1544 * that lwb's data being written to those vdevs (the
1545 * vdevs are flushed in the lwb write zio's completion
1546 * handler, zil_lwb_write_done()).
1548 if (last_lwb_opened->lwb_state != LWB_STATE_WRITE_DONE) {
1549 ASSERT(last_lwb_opened->lwb_state == LWB_STATE_OPENED ||
1550 last_lwb_opened->lwb_state == LWB_STATE_ISSUED);
1552 ASSERT3P(last_lwb_opened->lwb_write_zio, !=, NULL);
1553 zio_add_child(lwb->lwb_write_zio,
1554 last_lwb_opened->lwb_write_zio);
1561 * This function's purpose is to "open" an lwb such that it is ready to
1562 * accept new itxs being committed to it. To do this, the lwb's zio
1563 * structures are created, and linked to the lwb. This function is
1564 * idempotent; if the passed in lwb has already been opened, this
1565 * function is essentially a no-op.
1568 zil_lwb_write_open(zilog_t *zilog, lwb_t *lwb)
1570 zbookmark_phys_t zb;
1571 zio_priority_t prio;
1573 ASSERT(MUTEX_HELD(&zilog->zl_issuer_lock));
1574 ASSERT3P(lwb, !=, NULL);
1575 EQUIV(lwb->lwb_root_zio == NULL, lwb->lwb_state == LWB_STATE_CLOSED);
1576 EQUIV(lwb->lwb_root_zio != NULL, lwb->lwb_state == LWB_STATE_OPENED);
1578 SET_BOOKMARK(&zb, lwb->lwb_blk.blk_cksum.zc_word[ZIL_ZC_OBJSET],
1579 ZB_ZIL_OBJECT, ZB_ZIL_LEVEL,
1580 lwb->lwb_blk.blk_cksum.zc_word[ZIL_ZC_SEQ]);
1582 /* Lock so zil_sync() doesn't fastwrite_unmark after zio is created */
1583 mutex_enter(&zilog->zl_lock);
1584 if (lwb->lwb_root_zio == NULL) {
1585 abd_t *lwb_abd = abd_get_from_buf(lwb->lwb_buf,
1586 BP_GET_LSIZE(&lwb->lwb_blk));
1588 if (!lwb->lwb_fastwrite) {
1589 metaslab_fastwrite_mark(zilog->zl_spa, &lwb->lwb_blk);
1590 lwb->lwb_fastwrite = 1;
1593 if (!lwb->lwb_slog || zilog->zl_cur_used <= zil_slog_bulk)
1594 prio = ZIO_PRIORITY_SYNC_WRITE;
1596 prio = ZIO_PRIORITY_ASYNC_WRITE;
1598 lwb->lwb_root_zio = zio_root(zilog->zl_spa,
1599 zil_lwb_flush_vdevs_done, lwb, ZIO_FLAG_CANFAIL);
1600 ASSERT3P(lwb->lwb_root_zio, !=, NULL);
1602 lwb->lwb_write_zio = zio_rewrite(lwb->lwb_root_zio,
1603 zilog->zl_spa, 0, &lwb->lwb_blk, lwb_abd,
1604 BP_GET_LSIZE(&lwb->lwb_blk), zil_lwb_write_done, lwb,
1605 prio, ZIO_FLAG_CANFAIL | ZIO_FLAG_FASTWRITE, &zb);
1606 ASSERT3P(lwb->lwb_write_zio, !=, NULL);
1608 lwb->lwb_state = LWB_STATE_OPENED;
1610 zil_lwb_set_zio_dependency(zilog, lwb);
1611 zilog->zl_last_lwb_opened = lwb;
1613 mutex_exit(&zilog->zl_lock);
1615 ASSERT3P(lwb->lwb_root_zio, !=, NULL);
1616 ASSERT3P(lwb->lwb_write_zio, !=, NULL);
1617 ASSERT3S(lwb->lwb_state, ==, LWB_STATE_OPENED);
1621 * Define a limited set of intent log block sizes.
1623 * These must be a multiple of 4KB. Note only the amount used (again
1624 * aligned to 4KB) actually gets written. However, we can't always just
1625 * allocate SPA_OLD_MAXBLOCKSIZE as the slog space could be exhausted.
1627 static const struct {
1630 } zil_block_buckets[] = {
1631 { 4096, 4096 }, /* non TX_WRITE */
1632 { 8192 + 4096, 8192 + 4096 }, /* database */
1633 { 32768 + 4096, 32768 + 4096 }, /* NFS writes */
1634 { 65536 + 4096, 65536 + 4096 }, /* 64KB writes */
1635 { 131072, 131072 }, /* < 128KB writes */
1636 { 131072 +4096, 65536 + 4096 }, /* 128KB writes */
1637 { UINT64_MAX, SPA_OLD_MAXBLOCKSIZE}, /* > 128KB writes */
1641 * Maximum block size used by the ZIL. This is picked up when the ZIL is
1642 * initialized. Otherwise this should not be used directly; see
1643 * zl_max_block_size instead.
1645 static uint_t zil_maxblocksize = SPA_OLD_MAXBLOCKSIZE;
1648 * Start a log block write and advance to the next log block.
1649 * Calls are serialized.
1652 zil_lwb_write_issue(zilog_t *zilog, lwb_t *lwb)
1656 spa_t *spa = zilog->zl_spa;
1660 uint64_t zil_blksz, wsz;
1664 ASSERT(MUTEX_HELD(&zilog->zl_issuer_lock));
1665 ASSERT3P(lwb->lwb_root_zio, !=, NULL);
1666 ASSERT3P(lwb->lwb_write_zio, !=, NULL);
1667 ASSERT3S(lwb->lwb_state, ==, LWB_STATE_OPENED);
1669 if (BP_GET_CHECKSUM(&lwb->lwb_blk) == ZIO_CHECKSUM_ZILOG2) {
1670 zilc = (zil_chain_t *)lwb->lwb_buf;
1671 bp = &zilc->zc_next_blk;
1673 zilc = (zil_chain_t *)(lwb->lwb_buf + lwb->lwb_sz);
1674 bp = &zilc->zc_next_blk;
1677 ASSERT(lwb->lwb_nused <= lwb->lwb_sz);
1680 * Allocate the next block and save its address in this block
1681 * before writing it in order to establish the log chain.
1684 tx = dmu_tx_create(zilog->zl_os);
1687 * Since we are not going to create any new dirty data, and we
1688 * can even help with clearing the existing dirty data, we
1689 * should not be subject to the dirty data based delays. We
1690 * use TXG_NOTHROTTLE to bypass the delay mechanism.
1692 VERIFY0(dmu_tx_assign(tx, TXG_WAIT | TXG_NOTHROTTLE));
1694 dsl_dataset_dirty(dmu_objset_ds(zilog->zl_os), tx);
1695 txg = dmu_tx_get_txg(tx);
1697 mutex_enter(&zilog->zl_lwb_io_lock);
1698 lwb->lwb_issued_txg = txg;
1699 zilog->zl_lwb_inflight[txg & TXG_MASK]++;
1700 zilog->zl_lwb_max_issued_txg = MAX(txg, zilog->zl_lwb_max_issued_txg);
1701 mutex_exit(&zilog->zl_lwb_io_lock);
1704 * Log blocks are pre-allocated. Here we select the size of the next
1705 * block, based on size used in the last block.
1706 * - first find the smallest bucket that will fit the block from a
1707 * limited set of block sizes. This is because it's faster to write
1708 * blocks allocated from the same metaslab as they are adjacent or
1710 * - next find the maximum from the new suggested size and an array of
1711 * previous sizes. This lessens a picket fence effect of wrongly
1712 * guessing the size if we have a stream of say 2k, 64k, 2k, 64k
1715 * Note we only write what is used, but we can't just allocate
1716 * the maximum block size because we can exhaust the available
1719 zil_blksz = zilog->zl_cur_used + sizeof (zil_chain_t);
1720 for (i = 0; zil_blksz > zil_block_buckets[i].limit; i++)
1722 zil_blksz = MIN(zil_block_buckets[i].blksz, zilog->zl_max_block_size);
1723 zilog->zl_prev_blks[zilog->zl_prev_rotor] = zil_blksz;
1724 for (i = 0; i < ZIL_PREV_BLKS; i++)
1725 zil_blksz = MAX(zil_blksz, zilog->zl_prev_blks[i]);
1726 zilog->zl_prev_rotor = (zilog->zl_prev_rotor + 1) & (ZIL_PREV_BLKS - 1);
1729 error = zio_alloc_zil(spa, zilog->zl_os, txg, bp, zil_blksz, &slog);
1731 ZIL_STAT_BUMP(zilog, zil_itx_metaslab_slog_count);
1732 ZIL_STAT_INCR(zilog, zil_itx_metaslab_slog_bytes,
1735 ZIL_STAT_BUMP(zilog, zil_itx_metaslab_normal_count);
1736 ZIL_STAT_INCR(zilog, zil_itx_metaslab_normal_bytes,
1740 ASSERT3U(bp->blk_birth, ==, txg);
1741 bp->blk_cksum = lwb->lwb_blk.blk_cksum;
1742 bp->blk_cksum.zc_word[ZIL_ZC_SEQ]++;
1745 * Allocate a new log write block (lwb).
1747 nlwb = zil_alloc_lwb(zilog, bp, slog, txg, TRUE);
1750 if (BP_GET_CHECKSUM(&lwb->lwb_blk) == ZIO_CHECKSUM_ZILOG2) {
1751 /* For Slim ZIL only write what is used. */
1752 wsz = P2ROUNDUP_TYPED(lwb->lwb_nused, ZIL_MIN_BLKSZ, uint64_t);
1753 ASSERT3U(wsz, <=, lwb->lwb_sz);
1754 zio_shrink(lwb->lwb_write_zio, wsz);
1761 zilc->zc_nused = lwb->lwb_nused;
1762 zilc->zc_eck.zec_cksum = lwb->lwb_blk.blk_cksum;
1765 * clear unused data for security
1767 memset(lwb->lwb_buf + lwb->lwb_nused, 0, wsz - lwb->lwb_nused);
1769 spa_config_enter(zilog->zl_spa, SCL_STATE, lwb, RW_READER);
1771 zil_lwb_add_block(lwb, &lwb->lwb_blk);
1772 lwb->lwb_issued_timestamp = gethrtime();
1773 lwb->lwb_state = LWB_STATE_ISSUED;
1775 zio_nowait(lwb->lwb_root_zio);
1776 zio_nowait(lwb->lwb_write_zio);
1781 * If there was an allocation failure then nlwb will be null which
1782 * forces a txg_wait_synced().
1788 * Maximum amount of write data that can be put into single log block.
1791 zil_max_log_data(zilog_t *zilog)
1793 return (zilog->zl_max_block_size -
1794 sizeof (zil_chain_t) - sizeof (lr_write_t));
1798 * Maximum amount of log space we agree to waste to reduce number of
1799 * WR_NEED_COPY chunks to reduce zl_get_data() overhead (~12%).
1801 static inline uint64_t
1802 zil_max_waste_space(zilog_t *zilog)
1804 return (zil_max_log_data(zilog) / 8);
1808 * Maximum amount of write data for WR_COPIED. For correctness, consumers
1809 * must fall back to WR_NEED_COPY if we can't fit the entire record into one
1810 * maximum sized log block, because each WR_COPIED record must fit in a
1811 * single log block. For space efficiency, we want to fit two records into a
1812 * max-sized log block.
1815 zil_max_copied_data(zilog_t *zilog)
1817 return ((zilog->zl_max_block_size - sizeof (zil_chain_t)) / 2 -
1818 sizeof (lr_write_t));
1822 zil_lwb_commit(zilog_t *zilog, itx_t *itx, lwb_t *lwb)
1825 lr_write_t *lrwb, *lrw;
1827 uint64_t dlen, dnow, dpad, lwb_sp, reclen, txg, max_log_data;
1829 ASSERT(MUTEX_HELD(&zilog->zl_issuer_lock));
1830 ASSERT3P(lwb, !=, NULL);
1831 ASSERT3P(lwb->lwb_buf, !=, NULL);
1833 zil_lwb_write_open(zilog, lwb);
1836 lrw = (lr_write_t *)lrc;
1839 * A commit itx doesn't represent any on-disk state; instead
1840 * it's simply used as a place holder on the commit list, and
1841 * provides a mechanism for attaching a "commit waiter" onto the
1842 * correct lwb (such that the waiter can be signalled upon
1843 * completion of that lwb). Thus, we don't process this itx's
1844 * log record if it's a commit itx (these itx's don't have log
1845 * records), and instead link the itx's waiter onto the lwb's
1848 * For more details, see the comment above zil_commit().
1850 if (lrc->lrc_txtype == TX_COMMIT) {
1851 mutex_enter(&zilog->zl_lock);
1852 zil_commit_waiter_link_lwb(itx->itx_private, lwb);
1853 itx->itx_private = NULL;
1854 mutex_exit(&zilog->zl_lock);
1858 if (lrc->lrc_txtype == TX_WRITE && itx->itx_wr_state == WR_NEED_COPY) {
1859 dlen = P2ROUNDUP_TYPED(
1860 lrw->lr_length, sizeof (uint64_t), uint64_t);
1861 dpad = dlen - lrw->lr_length;
1865 reclen = lrc->lrc_reclen;
1866 zilog->zl_cur_used += (reclen + dlen);
1869 ASSERT3U(zilog->zl_cur_used, <, UINT64_MAX - (reclen + dlen));
1873 * If this record won't fit in the current log block, start a new one.
1874 * For WR_NEED_COPY optimize layout for minimal number of chunks.
1876 lwb_sp = lwb->lwb_sz - lwb->lwb_nused;
1877 max_log_data = zil_max_log_data(zilog);
1878 if (reclen > lwb_sp || (reclen + dlen > lwb_sp &&
1879 lwb_sp < zil_max_waste_space(zilog) &&
1880 (dlen % max_log_data == 0 ||
1881 lwb_sp < reclen + dlen % max_log_data))) {
1882 lwb = zil_lwb_write_issue(zilog, lwb);
1885 zil_lwb_write_open(zilog, lwb);
1886 ASSERT(LWB_EMPTY(lwb));
1887 lwb_sp = lwb->lwb_sz - lwb->lwb_nused;
1890 * There must be enough space in the new, empty log block to
1891 * hold reclen. For WR_COPIED, we need to fit the whole
1892 * record in one block, and reclen is the header size + the
1893 * data size. For WR_NEED_COPY, we can create multiple
1894 * records, splitting the data into multiple blocks, so we
1895 * only need to fit one word of data per block; in this case
1896 * reclen is just the header size (no data).
1898 ASSERT3U(reclen + MIN(dlen, sizeof (uint64_t)), <=, lwb_sp);
1901 dnow = MIN(dlen, lwb_sp - reclen);
1902 lr_buf = lwb->lwb_buf + lwb->lwb_nused;
1903 memcpy(lr_buf, lrc, reclen);
1904 lrcb = (lr_t *)lr_buf; /* Like lrc, but inside lwb. */
1905 lrwb = (lr_write_t *)lrcb; /* Like lrw, but inside lwb. */
1907 ZIL_STAT_BUMP(zilog, zil_itx_count);
1910 * If it's a write, fetch the data or get its blkptr as appropriate.
1912 if (lrc->lrc_txtype == TX_WRITE) {
1913 if (txg > spa_freeze_txg(zilog->zl_spa))
1914 txg_wait_synced(zilog->zl_dmu_pool, txg);
1915 if (itx->itx_wr_state == WR_COPIED) {
1916 ZIL_STAT_BUMP(zilog, zil_itx_copied_count);
1917 ZIL_STAT_INCR(zilog, zil_itx_copied_bytes,
1923 if (itx->itx_wr_state == WR_NEED_COPY) {
1924 dbuf = lr_buf + reclen;
1925 lrcb->lrc_reclen += dnow;
1926 if (lrwb->lr_length > dnow)
1927 lrwb->lr_length = dnow;
1928 lrw->lr_offset += dnow;
1929 lrw->lr_length -= dnow;
1930 ZIL_STAT_BUMP(zilog, zil_itx_needcopy_count);
1931 ZIL_STAT_INCR(zilog, zil_itx_needcopy_bytes,
1934 ASSERT3S(itx->itx_wr_state, ==, WR_INDIRECT);
1936 ZIL_STAT_BUMP(zilog, zil_itx_indirect_count);
1937 ZIL_STAT_INCR(zilog, zil_itx_indirect_bytes,
1942 * We pass in the "lwb_write_zio" rather than
1943 * "lwb_root_zio" so that the "lwb_write_zio"
1944 * becomes the parent of any zio's created by
1945 * the "zl_get_data" callback. The vdevs are
1946 * flushed after the "lwb_write_zio" completes,
1947 * so we want to make sure that completion
1948 * callback waits for these additional zio's,
1949 * such that the vdevs used by those zio's will
1950 * be included in the lwb's vdev tree, and those
1951 * vdevs will be properly flushed. If we passed
1952 * in "lwb_root_zio" here, then these additional
1953 * vdevs may not be flushed; e.g. if these zio's
1954 * completed after "lwb_write_zio" completed.
1956 error = zilog->zl_get_data(itx->itx_private,
1957 itx->itx_gen, lrwb, dbuf, lwb,
1958 lwb->lwb_write_zio);
1959 if (dbuf != NULL && error == 0 && dnow == dlen)
1960 /* Zero any padding bytes in the last block. */
1961 memset((char *)dbuf + lrwb->lr_length, 0, dpad);
1964 txg_wait_synced(zilog->zl_dmu_pool, txg);
1968 ASSERT(error == ENOENT || error == EEXIST ||
1976 * We're actually making an entry, so update lrc_seq to be the
1977 * log record sequence number. Note that this is generally not
1978 * equal to the itx sequence number because not all transactions
1979 * are synchronous, and sometimes spa_sync() gets there first.
1981 lrcb->lrc_seq = ++zilog->zl_lr_seq;
1982 lwb->lwb_nused += reclen + dnow;
1984 zil_lwb_add_txg(lwb, txg);
1986 ASSERT3U(lwb->lwb_nused, <=, lwb->lwb_sz);
1987 ASSERT0(P2PHASE(lwb->lwb_nused, sizeof (uint64_t)));
1991 zilog->zl_cur_used += reclen;
1999 zil_itx_create(uint64_t txtype, size_t olrsize)
2001 size_t itxsize, lrsize;
2004 lrsize = P2ROUNDUP_TYPED(olrsize, sizeof (uint64_t), size_t);
2005 itxsize = offsetof(itx_t, itx_lr) + lrsize;
2007 itx = zio_data_buf_alloc(itxsize);
2008 itx->itx_lr.lrc_txtype = txtype;
2009 itx->itx_lr.lrc_reclen = lrsize;
2010 itx->itx_lr.lrc_seq = 0; /* defensive */
2011 memset((char *)&itx->itx_lr + olrsize, 0, lrsize - olrsize);
2012 itx->itx_sync = B_TRUE; /* default is synchronous */
2013 itx->itx_callback = NULL;
2014 itx->itx_callback_data = NULL;
2015 itx->itx_size = itxsize;
2021 zil_itx_destroy(itx_t *itx)
2023 IMPLY(itx->itx_lr.lrc_txtype == TX_COMMIT, itx->itx_callback == NULL);
2024 IMPLY(itx->itx_callback != NULL, itx->itx_lr.lrc_txtype != TX_COMMIT);
2026 if (itx->itx_callback != NULL)
2027 itx->itx_callback(itx->itx_callback_data);
2029 zio_data_buf_free(itx, itx->itx_size);
2033 * Free up the sync and async itxs. The itxs_t has already been detached
2034 * so no locks are needed.
2037 zil_itxg_clean(void *arg)
2044 itx_async_node_t *ian;
2046 list = &itxs->i_sync_list;
2047 while ((itx = list_head(list)) != NULL) {
2049 * In the general case, commit itxs will not be found
2050 * here, as they'll be committed to an lwb via
2051 * zil_lwb_commit(), and free'd in that function. Having
2052 * said that, it is still possible for commit itxs to be
2053 * found here, due to the following race:
2055 * - a thread calls zil_commit() which assigns the
2056 * commit itx to a per-txg i_sync_list
2057 * - zil_itxg_clean() is called (e.g. via spa_sync())
2058 * while the waiter is still on the i_sync_list
2060 * There's nothing to prevent syncing the txg while the
2061 * waiter is on the i_sync_list. This normally doesn't
2062 * happen because spa_sync() is slower than zil_commit(),
2063 * but if zil_commit() calls txg_wait_synced() (e.g.
2064 * because zil_create() or zil_commit_writer_stall() is
2065 * called) we will hit this case.
2067 if (itx->itx_lr.lrc_txtype == TX_COMMIT)
2068 zil_commit_waiter_skip(itx->itx_private);
2070 list_remove(list, itx);
2071 zil_itx_destroy(itx);
2075 t = &itxs->i_async_tree;
2076 while ((ian = avl_destroy_nodes(t, &cookie)) != NULL) {
2077 list = &ian->ia_list;
2078 while ((itx = list_head(list)) != NULL) {
2079 list_remove(list, itx);
2080 /* commit itxs should never be on the async lists. */
2081 ASSERT3U(itx->itx_lr.lrc_txtype, !=, TX_COMMIT);
2082 zil_itx_destroy(itx);
2085 kmem_free(ian, sizeof (itx_async_node_t));
2089 kmem_free(itxs, sizeof (itxs_t));
2093 zil_aitx_compare(const void *x1, const void *x2)
2095 const uint64_t o1 = ((itx_async_node_t *)x1)->ia_foid;
2096 const uint64_t o2 = ((itx_async_node_t *)x2)->ia_foid;
2098 return (TREE_CMP(o1, o2));
2102 * Remove all async itx with the given oid.
2105 zil_remove_async(zilog_t *zilog, uint64_t oid)
2108 itx_async_node_t *ian;
2115 list_create(&clean_list, sizeof (itx_t), offsetof(itx_t, itx_node));
2117 if (spa_freeze_txg(zilog->zl_spa) != UINT64_MAX) /* ziltest support */
2120 otxg = spa_last_synced_txg(zilog->zl_spa) + 1;
2122 for (txg = otxg; txg < (otxg + TXG_CONCURRENT_STATES); txg++) {
2123 itxg_t *itxg = &zilog->zl_itxg[txg & TXG_MASK];
2125 mutex_enter(&itxg->itxg_lock);
2126 if (itxg->itxg_txg != txg) {
2127 mutex_exit(&itxg->itxg_lock);
2132 * Locate the object node and append its list.
2134 t = &itxg->itxg_itxs->i_async_tree;
2135 ian = avl_find(t, &oid, &where);
2137 list_move_tail(&clean_list, &ian->ia_list);
2138 mutex_exit(&itxg->itxg_lock);
2140 while ((itx = list_head(&clean_list)) != NULL) {
2141 list_remove(&clean_list, itx);
2142 /* commit itxs should never be on the async lists. */
2143 ASSERT3U(itx->itx_lr.lrc_txtype, !=, TX_COMMIT);
2144 zil_itx_destroy(itx);
2146 list_destroy(&clean_list);
2150 zil_itx_assign(zilog_t *zilog, itx_t *itx, dmu_tx_t *tx)
2154 itxs_t *itxs, *clean = NULL;
2157 * Ensure the data of a renamed file is committed before the rename.
2159 if ((itx->itx_lr.lrc_txtype & ~TX_CI) == TX_RENAME)
2160 zil_async_to_sync(zilog, itx->itx_oid);
2162 if (spa_freeze_txg(zilog->zl_spa) != UINT64_MAX)
2165 txg = dmu_tx_get_txg(tx);
2167 itxg = &zilog->zl_itxg[txg & TXG_MASK];
2168 mutex_enter(&itxg->itxg_lock);
2169 itxs = itxg->itxg_itxs;
2170 if (itxg->itxg_txg != txg) {
2173 * The zil_clean callback hasn't got around to cleaning
2174 * this itxg. Save the itxs for release below.
2175 * This should be rare.
2177 zfs_dbgmsg("zil_itx_assign: missed itx cleanup for "
2178 "txg %llu", (u_longlong_t)itxg->itxg_txg);
2179 clean = itxg->itxg_itxs;
2181 itxg->itxg_txg = txg;
2182 itxs = itxg->itxg_itxs = kmem_zalloc(sizeof (itxs_t),
2185 list_create(&itxs->i_sync_list, sizeof (itx_t),
2186 offsetof(itx_t, itx_node));
2187 avl_create(&itxs->i_async_tree, zil_aitx_compare,
2188 sizeof (itx_async_node_t),
2189 offsetof(itx_async_node_t, ia_node));
2191 if (itx->itx_sync) {
2192 list_insert_tail(&itxs->i_sync_list, itx);
2194 avl_tree_t *t = &itxs->i_async_tree;
2196 LR_FOID_GET_OBJ(((lr_ooo_t *)&itx->itx_lr)->lr_foid);
2197 itx_async_node_t *ian;
2200 ian = avl_find(t, &foid, &where);
2202 ian = kmem_alloc(sizeof (itx_async_node_t),
2204 list_create(&ian->ia_list, sizeof (itx_t),
2205 offsetof(itx_t, itx_node));
2206 ian->ia_foid = foid;
2207 avl_insert(t, ian, where);
2209 list_insert_tail(&ian->ia_list, itx);
2212 itx->itx_lr.lrc_txg = dmu_tx_get_txg(tx);
2215 * We don't want to dirty the ZIL using ZILTEST_TXG, because
2216 * zil_clean() will never be called using ZILTEST_TXG. Thus, we
2217 * need to be careful to always dirty the ZIL using the "real"
2218 * TXG (not itxg_txg) even when the SPA is frozen.
2220 zilog_dirty(zilog, dmu_tx_get_txg(tx));
2221 mutex_exit(&itxg->itxg_lock);
2223 /* Release the old itxs now we've dropped the lock */
2225 zil_itxg_clean(clean);
2229 * If there are any in-memory intent log transactions which have now been
2230 * synced then start up a taskq to free them. We should only do this after we
2231 * have written out the uberblocks (i.e. txg has been committed) so that
2232 * don't inadvertently clean out in-memory log records that would be required
2236 zil_clean(zilog_t *zilog, uint64_t synced_txg)
2238 itxg_t *itxg = &zilog->zl_itxg[synced_txg & TXG_MASK];
2241 ASSERT3U(synced_txg, <, ZILTEST_TXG);
2243 mutex_enter(&itxg->itxg_lock);
2244 if (itxg->itxg_itxs == NULL || itxg->itxg_txg == ZILTEST_TXG) {
2245 mutex_exit(&itxg->itxg_lock);
2248 ASSERT3U(itxg->itxg_txg, <=, synced_txg);
2249 ASSERT3U(itxg->itxg_txg, !=, 0);
2250 clean_me = itxg->itxg_itxs;
2251 itxg->itxg_itxs = NULL;
2253 mutex_exit(&itxg->itxg_lock);
2255 * Preferably start a task queue to free up the old itxs but
2256 * if taskq_dispatch can't allocate resources to do that then
2257 * free it in-line. This should be rare. Note, using TQ_SLEEP
2258 * created a bad performance problem.
2260 ASSERT3P(zilog->zl_dmu_pool, !=, NULL);
2261 ASSERT3P(zilog->zl_dmu_pool->dp_zil_clean_taskq, !=, NULL);
2262 taskqid_t id = taskq_dispatch(zilog->zl_dmu_pool->dp_zil_clean_taskq,
2263 zil_itxg_clean, clean_me, TQ_NOSLEEP);
2264 if (id == TASKQID_INVALID)
2265 zil_itxg_clean(clean_me);
2269 * This function will traverse the queue of itxs that need to be
2270 * committed, and move them onto the ZIL's zl_itx_commit_list.
2273 zil_get_commit_list(zilog_t *zilog)
2276 list_t *commit_list = &zilog->zl_itx_commit_list;
2278 ASSERT(MUTEX_HELD(&zilog->zl_issuer_lock));
2280 if (spa_freeze_txg(zilog->zl_spa) != UINT64_MAX) /* ziltest support */
2283 otxg = spa_last_synced_txg(zilog->zl_spa) + 1;
2286 * This is inherently racy, since there is nothing to prevent
2287 * the last synced txg from changing. That's okay since we'll
2288 * only commit things in the future.
2290 for (txg = otxg; txg < (otxg + TXG_CONCURRENT_STATES); txg++) {
2291 itxg_t *itxg = &zilog->zl_itxg[txg & TXG_MASK];
2293 mutex_enter(&itxg->itxg_lock);
2294 if (itxg->itxg_txg != txg) {
2295 mutex_exit(&itxg->itxg_lock);
2300 * If we're adding itx records to the zl_itx_commit_list,
2301 * then the zil better be dirty in this "txg". We can assert
2302 * that here since we're holding the itxg_lock which will
2303 * prevent spa_sync from cleaning it. Once we add the itxs
2304 * to the zl_itx_commit_list we must commit it to disk even
2305 * if it's unnecessary (i.e. the txg was synced).
2307 ASSERT(zilog_is_dirty_in_txg(zilog, txg) ||
2308 spa_freeze_txg(zilog->zl_spa) != UINT64_MAX);
2309 list_move_tail(commit_list, &itxg->itxg_itxs->i_sync_list);
2311 mutex_exit(&itxg->itxg_lock);
2316 * Move the async itxs for a specified object to commit into sync lists.
2319 zil_async_to_sync(zilog_t *zilog, uint64_t foid)
2322 itx_async_node_t *ian;
2326 if (spa_freeze_txg(zilog->zl_spa) != UINT64_MAX) /* ziltest support */
2329 otxg = spa_last_synced_txg(zilog->zl_spa) + 1;
2332 * This is inherently racy, since there is nothing to prevent
2333 * the last synced txg from changing.
2335 for (txg = otxg; txg < (otxg + TXG_CONCURRENT_STATES); txg++) {
2336 itxg_t *itxg = &zilog->zl_itxg[txg & TXG_MASK];
2338 mutex_enter(&itxg->itxg_lock);
2339 if (itxg->itxg_txg != txg) {
2340 mutex_exit(&itxg->itxg_lock);
2345 * If a foid is specified then find that node and append its
2346 * list. Otherwise walk the tree appending all the lists
2347 * to the sync list. We add to the end rather than the
2348 * beginning to ensure the create has happened.
2350 t = &itxg->itxg_itxs->i_async_tree;
2352 ian = avl_find(t, &foid, &where);
2354 list_move_tail(&itxg->itxg_itxs->i_sync_list,
2358 void *cookie = NULL;
2360 while ((ian = avl_destroy_nodes(t, &cookie)) != NULL) {
2361 list_move_tail(&itxg->itxg_itxs->i_sync_list,
2363 list_destroy(&ian->ia_list);
2364 kmem_free(ian, sizeof (itx_async_node_t));
2367 mutex_exit(&itxg->itxg_lock);
2372 * This function will prune commit itxs that are at the head of the
2373 * commit list (it won't prune past the first non-commit itx), and
2374 * either: a) attach them to the last lwb that's still pending
2375 * completion, or b) skip them altogether.
2377 * This is used as a performance optimization to prevent commit itxs
2378 * from generating new lwbs when it's unnecessary to do so.
2381 zil_prune_commit_list(zilog_t *zilog)
2385 ASSERT(MUTEX_HELD(&zilog->zl_issuer_lock));
2387 while ((itx = list_head(&zilog->zl_itx_commit_list)) != NULL) {
2388 lr_t *lrc = &itx->itx_lr;
2389 if (lrc->lrc_txtype != TX_COMMIT)
2392 mutex_enter(&zilog->zl_lock);
2394 lwb_t *last_lwb = zilog->zl_last_lwb_opened;
2395 if (last_lwb == NULL ||
2396 last_lwb->lwb_state == LWB_STATE_FLUSH_DONE) {
2398 * All of the itxs this waiter was waiting on
2399 * must have already completed (or there were
2400 * never any itx's for it to wait on), so it's
2401 * safe to skip this waiter and mark it done.
2403 zil_commit_waiter_skip(itx->itx_private);
2405 zil_commit_waiter_link_lwb(itx->itx_private, last_lwb);
2406 itx->itx_private = NULL;
2409 mutex_exit(&zilog->zl_lock);
2411 list_remove(&zilog->zl_itx_commit_list, itx);
2412 zil_itx_destroy(itx);
2415 IMPLY(itx != NULL, itx->itx_lr.lrc_txtype != TX_COMMIT);
2419 zil_commit_writer_stall(zilog_t *zilog)
2422 * When zio_alloc_zil() fails to allocate the next lwb block on
2423 * disk, we must call txg_wait_synced() to ensure all of the
2424 * lwbs in the zilog's zl_lwb_list are synced and then freed (in
2425 * zil_sync()), such that any subsequent ZIL writer (i.e. a call
2426 * to zil_process_commit_list()) will have to call zil_create(),
2427 * and start a new ZIL chain.
2429 * Since zil_alloc_zil() failed, the lwb that was previously
2430 * issued does not have a pointer to the "next" lwb on disk.
2431 * Thus, if another ZIL writer thread was to allocate the "next"
2432 * on-disk lwb, that block could be leaked in the event of a
2433 * crash (because the previous lwb on-disk would not point to
2436 * We must hold the zilog's zl_issuer_lock while we do this, to
2437 * ensure no new threads enter zil_process_commit_list() until
2438 * all lwb's in the zl_lwb_list have been synced and freed
2439 * (which is achieved via the txg_wait_synced() call).
2441 ASSERT(MUTEX_HELD(&zilog->zl_issuer_lock));
2442 txg_wait_synced(zilog->zl_dmu_pool, 0);
2443 ASSERT3P(list_tail(&zilog->zl_lwb_list), ==, NULL);
2447 * This function will traverse the commit list, creating new lwbs as
2448 * needed, and committing the itxs from the commit list to these newly
2449 * created lwbs. Additionally, as a new lwb is created, the previous
2450 * lwb will be issued to the zio layer to be written to disk.
2453 zil_process_commit_list(zilog_t *zilog)
2455 spa_t *spa = zilog->zl_spa;
2457 list_t nolwb_waiters;
2461 ASSERT(MUTEX_HELD(&zilog->zl_issuer_lock));
2464 * Return if there's nothing to commit before we dirty the fs by
2465 * calling zil_create().
2467 if (list_head(&zilog->zl_itx_commit_list) == NULL)
2470 list_create(&nolwb_itxs, sizeof (itx_t), offsetof(itx_t, itx_node));
2471 list_create(&nolwb_waiters, sizeof (zil_commit_waiter_t),
2472 offsetof(zil_commit_waiter_t, zcw_node));
2474 lwb = list_tail(&zilog->zl_lwb_list);
2476 lwb = zil_create(zilog);
2479 * Activate SPA_FEATURE_ZILSAXATTR for the cases where ZIL will
2480 * have already been created (zl_lwb_list not empty).
2482 zil_commit_activate_saxattr_feature(zilog);
2483 ASSERT3S(lwb->lwb_state, !=, LWB_STATE_ISSUED);
2484 ASSERT3S(lwb->lwb_state, !=, LWB_STATE_WRITE_DONE);
2485 ASSERT3S(lwb->lwb_state, !=, LWB_STATE_FLUSH_DONE);
2488 while ((itx = list_head(&zilog->zl_itx_commit_list)) != NULL) {
2489 lr_t *lrc = &itx->itx_lr;
2490 uint64_t txg = lrc->lrc_txg;
2492 ASSERT3U(txg, !=, 0);
2494 if (lrc->lrc_txtype == TX_COMMIT) {
2495 DTRACE_PROBE2(zil__process__commit__itx,
2496 zilog_t *, zilog, itx_t *, itx);
2498 DTRACE_PROBE2(zil__process__normal__itx,
2499 zilog_t *, zilog, itx_t *, itx);
2502 list_remove(&zilog->zl_itx_commit_list, itx);
2504 boolean_t synced = txg <= spa_last_synced_txg(spa);
2505 boolean_t frozen = txg > spa_freeze_txg(spa);
2508 * If the txg of this itx has already been synced out, then
2509 * we don't need to commit this itx to an lwb. This is
2510 * because the data of this itx will have already been
2511 * written to the main pool. This is inherently racy, and
2512 * it's still ok to commit an itx whose txg has already
2513 * been synced; this will result in a write that's
2514 * unnecessary, but will do no harm.
2516 * With that said, we always want to commit TX_COMMIT itxs
2517 * to an lwb, regardless of whether or not that itx's txg
2518 * has been synced out. We do this to ensure any OPENED lwb
2519 * will always have at least one zil_commit_waiter_t linked
2522 * As a counter-example, if we skipped TX_COMMIT itx's
2523 * whose txg had already been synced, the following
2524 * situation could occur if we happened to be racing with
2527 * 1. We commit a non-TX_COMMIT itx to an lwb, where the
2528 * itx's txg is 10 and the last synced txg is 9.
2529 * 2. spa_sync finishes syncing out txg 10.
2530 * 3. We move to the next itx in the list, it's a TX_COMMIT
2531 * whose txg is 10, so we skip it rather than committing
2532 * it to the lwb used in (1).
2534 * If the itx that is skipped in (3) is the last TX_COMMIT
2535 * itx in the commit list, than it's possible for the lwb
2536 * used in (1) to remain in the OPENED state indefinitely.
2538 * To prevent the above scenario from occurring, ensuring
2539 * that once an lwb is OPENED it will transition to ISSUED
2540 * and eventually DONE, we always commit TX_COMMIT itx's to
2541 * an lwb here, even if that itx's txg has already been
2544 * Finally, if the pool is frozen, we _always_ commit the
2545 * itx. The point of freezing the pool is to prevent data
2546 * from being written to the main pool via spa_sync, and
2547 * instead rely solely on the ZIL to persistently store the
2548 * data; i.e. when the pool is frozen, the last synced txg
2549 * value can't be trusted.
2551 if (frozen || !synced || lrc->lrc_txtype == TX_COMMIT) {
2553 lwb = zil_lwb_commit(zilog, itx, lwb);
2556 list_insert_tail(&nolwb_itxs, itx);
2558 list_insert_tail(&lwb->lwb_itxs, itx);
2560 if (lrc->lrc_txtype == TX_COMMIT) {
2561 zil_commit_waiter_link_nolwb(
2562 itx->itx_private, &nolwb_waiters);
2565 list_insert_tail(&nolwb_itxs, itx);
2568 ASSERT3S(lrc->lrc_txtype, !=, TX_COMMIT);
2569 zil_itx_destroy(itx);
2575 * This indicates zio_alloc_zil() failed to allocate the
2576 * "next" lwb on-disk. When this happens, we must stall
2577 * the ZIL write pipeline; see the comment within
2578 * zil_commit_writer_stall() for more details.
2580 zil_commit_writer_stall(zilog);
2583 * Additionally, we have to signal and mark the "nolwb"
2584 * waiters as "done" here, since without an lwb, we
2585 * can't do this via zil_lwb_flush_vdevs_done() like
2588 zil_commit_waiter_t *zcw;
2589 while ((zcw = list_head(&nolwb_waiters)) != NULL) {
2590 zil_commit_waiter_skip(zcw);
2591 list_remove(&nolwb_waiters, zcw);
2595 * And finally, we have to destroy the itx's that
2596 * couldn't be committed to an lwb; this will also call
2597 * the itx's callback if one exists for the itx.
2599 while ((itx = list_head(&nolwb_itxs)) != NULL) {
2600 list_remove(&nolwb_itxs, itx);
2601 zil_itx_destroy(itx);
2604 ASSERT(list_is_empty(&nolwb_waiters));
2605 ASSERT3P(lwb, !=, NULL);
2606 ASSERT3S(lwb->lwb_state, !=, LWB_STATE_ISSUED);
2607 ASSERT3S(lwb->lwb_state, !=, LWB_STATE_WRITE_DONE);
2608 ASSERT3S(lwb->lwb_state, !=, LWB_STATE_FLUSH_DONE);
2611 * At this point, the ZIL block pointed at by the "lwb"
2612 * variable is in one of the following states: "closed"
2615 * If it's "closed", then no itxs have been committed to
2616 * it, so there's no point in issuing its zio (i.e. it's
2619 * If it's "open", then it contains one or more itxs that
2620 * eventually need to be committed to stable storage. In
2621 * this case we intentionally do not issue the lwb's zio
2622 * to disk yet, and instead rely on one of the following
2623 * two mechanisms for issuing the zio:
2625 * 1. Ideally, there will be more ZIL activity occurring
2626 * on the system, such that this function will be
2627 * immediately called again (not necessarily by the same
2628 * thread) and this lwb's zio will be issued via
2629 * zil_lwb_commit(). This way, the lwb is guaranteed to
2630 * be "full" when it is issued to disk, and we'll make
2631 * use of the lwb's size the best we can.
2633 * 2. If there isn't sufficient ZIL activity occurring on
2634 * the system, such that this lwb's zio isn't issued via
2635 * zil_lwb_commit(), zil_commit_waiter() will issue the
2636 * lwb's zio. If this occurs, the lwb is not guaranteed
2637 * to be "full" by the time its zio is issued, and means
2638 * the size of the lwb was "too large" given the amount
2639 * of ZIL activity occurring on the system at that time.
2641 * We do this for a couple of reasons:
2643 * 1. To try and reduce the number of IOPs needed to
2644 * write the same number of itxs. If an lwb has space
2645 * available in its buffer for more itxs, and more itxs
2646 * will be committed relatively soon (relative to the
2647 * latency of performing a write), then it's beneficial
2648 * to wait for these "next" itxs. This way, more itxs
2649 * can be committed to stable storage with fewer writes.
2651 * 2. To try and use the largest lwb block size that the
2652 * incoming rate of itxs can support. Again, this is to
2653 * try and pack as many itxs into as few lwbs as
2654 * possible, without significantly impacting the latency
2655 * of each individual itx.
2661 * This function is responsible for ensuring the passed in commit waiter
2662 * (and associated commit itx) is committed to an lwb. If the waiter is
2663 * not already committed to an lwb, all itxs in the zilog's queue of
2664 * itxs will be processed. The assumption is the passed in waiter's
2665 * commit itx will found in the queue just like the other non-commit
2666 * itxs, such that when the entire queue is processed, the waiter will
2667 * have been committed to an lwb.
2669 * The lwb associated with the passed in waiter is not guaranteed to
2670 * have been issued by the time this function completes. If the lwb is
2671 * not issued, we rely on future calls to zil_commit_writer() to issue
2672 * the lwb, or the timeout mechanism found in zil_commit_waiter().
2675 zil_commit_writer(zilog_t *zilog, zil_commit_waiter_t *zcw)
2677 ASSERT(!MUTEX_HELD(&zilog->zl_lock));
2678 ASSERT(spa_writeable(zilog->zl_spa));
2680 mutex_enter(&zilog->zl_issuer_lock);
2682 if (zcw->zcw_lwb != NULL || zcw->zcw_done) {
2684 * It's possible that, while we were waiting to acquire
2685 * the "zl_issuer_lock", another thread committed this
2686 * waiter to an lwb. If that occurs, we bail out early,
2687 * without processing any of the zilog's queue of itxs.
2689 * On certain workloads and system configurations, the
2690 * "zl_issuer_lock" can become highly contended. In an
2691 * attempt to reduce this contention, we immediately drop
2692 * the lock if the waiter has already been processed.
2694 * We've measured this optimization to reduce CPU spent
2695 * contending on this lock by up to 5%, using a system
2696 * with 32 CPUs, low latency storage (~50 usec writes),
2697 * and 1024 threads performing sync writes.
2702 ZIL_STAT_BUMP(zilog, zil_commit_writer_count);
2704 zil_get_commit_list(zilog);
2705 zil_prune_commit_list(zilog);
2706 zil_process_commit_list(zilog);
2709 mutex_exit(&zilog->zl_issuer_lock);
2713 zil_commit_waiter_timeout(zilog_t *zilog, zil_commit_waiter_t *zcw)
2715 ASSERT(!MUTEX_HELD(&zilog->zl_issuer_lock));
2716 ASSERT(MUTEX_HELD(&zcw->zcw_lock));
2717 ASSERT3B(zcw->zcw_done, ==, B_FALSE);
2719 lwb_t *lwb = zcw->zcw_lwb;
2720 ASSERT3P(lwb, !=, NULL);
2721 ASSERT3S(lwb->lwb_state, !=, LWB_STATE_CLOSED);
2724 * If the lwb has already been issued by another thread, we can
2725 * immediately return since there's no work to be done (the
2726 * point of this function is to issue the lwb). Additionally, we
2727 * do this prior to acquiring the zl_issuer_lock, to avoid
2728 * acquiring it when it's not necessary to do so.
2730 if (lwb->lwb_state == LWB_STATE_ISSUED ||
2731 lwb->lwb_state == LWB_STATE_WRITE_DONE ||
2732 lwb->lwb_state == LWB_STATE_FLUSH_DONE)
2736 * In order to call zil_lwb_write_issue() we must hold the
2737 * zilog's "zl_issuer_lock". We can't simply acquire that lock,
2738 * since we're already holding the commit waiter's "zcw_lock",
2739 * and those two locks are acquired in the opposite order
2742 mutex_exit(&zcw->zcw_lock);
2743 mutex_enter(&zilog->zl_issuer_lock);
2744 mutex_enter(&zcw->zcw_lock);
2747 * Since we just dropped and re-acquired the commit waiter's
2748 * lock, we have to re-check to see if the waiter was marked
2749 * "done" during that process. If the waiter was marked "done",
2750 * the "lwb" pointer is no longer valid (it can be free'd after
2751 * the waiter is marked "done"), so without this check we could
2752 * wind up with a use-after-free error below.
2757 ASSERT3P(lwb, ==, zcw->zcw_lwb);
2760 * We've already checked this above, but since we hadn't acquired
2761 * the zilog's zl_issuer_lock, we have to perform this check a
2762 * second time while holding the lock.
2764 * We don't need to hold the zl_lock since the lwb cannot transition
2765 * from OPENED to ISSUED while we hold the zl_issuer_lock. The lwb
2766 * _can_ transition from ISSUED to DONE, but it's OK to race with
2767 * that transition since we treat the lwb the same, whether it's in
2768 * the ISSUED or DONE states.
2770 * The important thing, is we treat the lwb differently depending on
2771 * if it's ISSUED or OPENED, and block any other threads that might
2772 * attempt to issue this lwb. For that reason we hold the
2773 * zl_issuer_lock when checking the lwb_state; we must not call
2774 * zil_lwb_write_issue() if the lwb had already been issued.
2776 * See the comment above the lwb_state_t structure definition for
2777 * more details on the lwb states, and locking requirements.
2779 if (lwb->lwb_state == LWB_STATE_ISSUED ||
2780 lwb->lwb_state == LWB_STATE_WRITE_DONE ||
2781 lwb->lwb_state == LWB_STATE_FLUSH_DONE)
2784 ASSERT3S(lwb->lwb_state, ==, LWB_STATE_OPENED);
2787 * As described in the comments above zil_commit_waiter() and
2788 * zil_process_commit_list(), we need to issue this lwb's zio
2789 * since we've reached the commit waiter's timeout and it still
2790 * hasn't been issued.
2792 lwb_t *nlwb = zil_lwb_write_issue(zilog, lwb);
2794 IMPLY(nlwb != NULL, lwb->lwb_state != LWB_STATE_OPENED);
2797 * Since the lwb's zio hadn't been issued by the time this thread
2798 * reached its timeout, we reset the zilog's "zl_cur_used" field
2799 * to influence the zil block size selection algorithm.
2801 * By having to issue the lwb's zio here, it means the size of the
2802 * lwb was too large, given the incoming throughput of itxs. By
2803 * setting "zl_cur_used" to zero, we communicate this fact to the
2804 * block size selection algorithm, so it can take this information
2805 * into account, and potentially select a smaller size for the
2806 * next lwb block that is allocated.
2808 zilog->zl_cur_used = 0;
2812 * When zil_lwb_write_issue() returns NULL, this
2813 * indicates zio_alloc_zil() failed to allocate the
2814 * "next" lwb on-disk. When this occurs, the ZIL write
2815 * pipeline must be stalled; see the comment within the
2816 * zil_commit_writer_stall() function for more details.
2818 * We must drop the commit waiter's lock prior to
2819 * calling zil_commit_writer_stall() or else we can wind
2820 * up with the following deadlock:
2822 * - This thread is waiting for the txg to sync while
2823 * holding the waiter's lock; txg_wait_synced() is
2824 * used within txg_commit_writer_stall().
2826 * - The txg can't sync because it is waiting for this
2827 * lwb's zio callback to call dmu_tx_commit().
2829 * - The lwb's zio callback can't call dmu_tx_commit()
2830 * because it's blocked trying to acquire the waiter's
2831 * lock, which occurs prior to calling dmu_tx_commit()
2833 mutex_exit(&zcw->zcw_lock);
2834 zil_commit_writer_stall(zilog);
2835 mutex_enter(&zcw->zcw_lock);
2839 mutex_exit(&zilog->zl_issuer_lock);
2840 ASSERT(MUTEX_HELD(&zcw->zcw_lock));
2844 * This function is responsible for performing the following two tasks:
2846 * 1. its primary responsibility is to block until the given "commit
2847 * waiter" is considered "done".
2849 * 2. its secondary responsibility is to issue the zio for the lwb that
2850 * the given "commit waiter" is waiting on, if this function has
2851 * waited "long enough" and the lwb is still in the "open" state.
2853 * Given a sufficient amount of itxs being generated and written using
2854 * the ZIL, the lwb's zio will be issued via the zil_lwb_commit()
2855 * function. If this does not occur, this secondary responsibility will
2856 * ensure the lwb is issued even if there is not other synchronous
2857 * activity on the system.
2859 * For more details, see zil_process_commit_list(); more specifically,
2860 * the comment at the bottom of that function.
2863 zil_commit_waiter(zilog_t *zilog, zil_commit_waiter_t *zcw)
2865 ASSERT(!MUTEX_HELD(&zilog->zl_lock));
2866 ASSERT(!MUTEX_HELD(&zilog->zl_issuer_lock));
2867 ASSERT(spa_writeable(zilog->zl_spa));
2869 mutex_enter(&zcw->zcw_lock);
2872 * The timeout is scaled based on the lwb latency to avoid
2873 * significantly impacting the latency of each individual itx.
2874 * For more details, see the comment at the bottom of the
2875 * zil_process_commit_list() function.
2877 int pct = MAX(zfs_commit_timeout_pct, 1);
2878 hrtime_t sleep = (zilog->zl_last_lwb_latency * pct) / 100;
2879 hrtime_t wakeup = gethrtime() + sleep;
2880 boolean_t timedout = B_FALSE;
2882 while (!zcw->zcw_done) {
2883 ASSERT(MUTEX_HELD(&zcw->zcw_lock));
2885 lwb_t *lwb = zcw->zcw_lwb;
2888 * Usually, the waiter will have a non-NULL lwb field here,
2889 * but it's possible for it to be NULL as a result of
2890 * zil_commit() racing with spa_sync().
2892 * When zil_clean() is called, it's possible for the itxg
2893 * list (which may be cleaned via a taskq) to contain
2894 * commit itxs. When this occurs, the commit waiters linked
2895 * off of these commit itxs will not be committed to an
2896 * lwb. Additionally, these commit waiters will not be
2897 * marked done until zil_commit_waiter_skip() is called via
2900 * Thus, it's possible for this commit waiter (i.e. the
2901 * "zcw" variable) to be found in this "in between" state;
2902 * where it's "zcw_lwb" field is NULL, and it hasn't yet
2903 * been skipped, so it's "zcw_done" field is still B_FALSE.
2905 IMPLY(lwb != NULL, lwb->lwb_state != LWB_STATE_CLOSED);
2907 if (lwb != NULL && lwb->lwb_state == LWB_STATE_OPENED) {
2908 ASSERT3B(timedout, ==, B_FALSE);
2911 * If the lwb hasn't been issued yet, then we
2912 * need to wait with a timeout, in case this
2913 * function needs to issue the lwb after the
2914 * timeout is reached; responsibility (2) from
2915 * the comment above this function.
2917 int rc = cv_timedwait_hires(&zcw->zcw_cv,
2918 &zcw->zcw_lock, wakeup, USEC2NSEC(1),
2919 CALLOUT_FLAG_ABSOLUTE);
2921 if (rc != -1 || zcw->zcw_done)
2925 zil_commit_waiter_timeout(zilog, zcw);
2927 if (!zcw->zcw_done) {
2929 * If the commit waiter has already been
2930 * marked "done", it's possible for the
2931 * waiter's lwb structure to have already
2932 * been freed. Thus, we can only reliably
2933 * make these assertions if the waiter
2936 ASSERT3P(lwb, ==, zcw->zcw_lwb);
2937 ASSERT3S(lwb->lwb_state, !=, LWB_STATE_OPENED);
2941 * If the lwb isn't open, then it must have already
2942 * been issued. In that case, there's no need to
2943 * use a timeout when waiting for the lwb to
2946 * Additionally, if the lwb is NULL, the waiter
2947 * will soon be signaled and marked done via
2948 * zil_clean() and zil_itxg_clean(), so no timeout
2953 lwb->lwb_state == LWB_STATE_ISSUED ||
2954 lwb->lwb_state == LWB_STATE_WRITE_DONE ||
2955 lwb->lwb_state == LWB_STATE_FLUSH_DONE);
2956 cv_wait(&zcw->zcw_cv, &zcw->zcw_lock);
2960 mutex_exit(&zcw->zcw_lock);
2963 static zil_commit_waiter_t *
2964 zil_alloc_commit_waiter(void)
2966 zil_commit_waiter_t *zcw = kmem_cache_alloc(zil_zcw_cache, KM_SLEEP);
2968 cv_init(&zcw->zcw_cv, NULL, CV_DEFAULT, NULL);
2969 mutex_init(&zcw->zcw_lock, NULL, MUTEX_DEFAULT, NULL);
2970 list_link_init(&zcw->zcw_node);
2971 zcw->zcw_lwb = NULL;
2972 zcw->zcw_done = B_FALSE;
2973 zcw->zcw_zio_error = 0;
2979 zil_free_commit_waiter(zil_commit_waiter_t *zcw)
2981 ASSERT(!list_link_active(&zcw->zcw_node));
2982 ASSERT3P(zcw->zcw_lwb, ==, NULL);
2983 ASSERT3B(zcw->zcw_done, ==, B_TRUE);
2984 mutex_destroy(&zcw->zcw_lock);
2985 cv_destroy(&zcw->zcw_cv);
2986 kmem_cache_free(zil_zcw_cache, zcw);
2990 * This function is used to create a TX_COMMIT itx and assign it. This
2991 * way, it will be linked into the ZIL's list of synchronous itxs, and
2992 * then later committed to an lwb (or skipped) when
2993 * zil_process_commit_list() is called.
2996 zil_commit_itx_assign(zilog_t *zilog, zil_commit_waiter_t *zcw)
2998 dmu_tx_t *tx = dmu_tx_create(zilog->zl_os);
2999 VERIFY0(dmu_tx_assign(tx, TXG_WAIT));
3001 itx_t *itx = zil_itx_create(TX_COMMIT, sizeof (lr_t));
3002 itx->itx_sync = B_TRUE;
3003 itx->itx_private = zcw;
3005 zil_itx_assign(zilog, itx, tx);
3011 * Commit ZFS Intent Log transactions (itxs) to stable storage.
3013 * When writing ZIL transactions to the on-disk representation of the
3014 * ZIL, the itxs are committed to a Log Write Block (lwb). Multiple
3015 * itxs can be committed to a single lwb. Once a lwb is written and
3016 * committed to stable storage (i.e. the lwb is written, and vdevs have
3017 * been flushed), each itx that was committed to that lwb is also
3018 * considered to be committed to stable storage.
3020 * When an itx is committed to an lwb, the log record (lr_t) contained
3021 * by the itx is copied into the lwb's zio buffer, and once this buffer
3022 * is written to disk, it becomes an on-disk ZIL block.
3024 * As itxs are generated, they're inserted into the ZIL's queue of
3025 * uncommitted itxs. The semantics of zil_commit() are such that it will
3026 * block until all itxs that were in the queue when it was called, are
3027 * committed to stable storage.
3029 * If "foid" is zero, this means all "synchronous" and "asynchronous"
3030 * itxs, for all objects in the dataset, will be committed to stable
3031 * storage prior to zil_commit() returning. If "foid" is non-zero, all
3032 * "synchronous" itxs for all objects, but only "asynchronous" itxs
3033 * that correspond to the foid passed in, will be committed to stable
3034 * storage prior to zil_commit() returning.
3036 * Generally speaking, when zil_commit() is called, the consumer doesn't
3037 * actually care about _all_ of the uncommitted itxs. Instead, they're
3038 * simply trying to waiting for a specific itx to be committed to disk,
3039 * but the interface(s) for interacting with the ZIL don't allow such
3040 * fine-grained communication. A better interface would allow a consumer
3041 * to create and assign an itx, and then pass a reference to this itx to
3042 * zil_commit(); such that zil_commit() would return as soon as that
3043 * specific itx was committed to disk (instead of waiting for _all_
3044 * itxs to be committed).
3046 * When a thread calls zil_commit() a special "commit itx" will be
3047 * generated, along with a corresponding "waiter" for this commit itx.
3048 * zil_commit() will wait on this waiter's CV, such that when the waiter
3049 * is marked done, and signaled, zil_commit() will return.
3051 * This commit itx is inserted into the queue of uncommitted itxs. This
3052 * provides an easy mechanism for determining which itxs were in the
3053 * queue prior to zil_commit() having been called, and which itxs were
3054 * added after zil_commit() was called.
3056 * The commit itx is special; it doesn't have any on-disk representation.
3057 * When a commit itx is "committed" to an lwb, the waiter associated
3058 * with it is linked onto the lwb's list of waiters. Then, when that lwb
3059 * completes, each waiter on the lwb's list is marked done and signaled
3060 * -- allowing the thread waiting on the waiter to return from zil_commit().
3062 * It's important to point out a few critical factors that allow us
3063 * to make use of the commit itxs, commit waiters, per-lwb lists of
3064 * commit waiters, and zio completion callbacks like we're doing:
3066 * 1. The list of waiters for each lwb is traversed, and each commit
3067 * waiter is marked "done" and signaled, in the zio completion
3068 * callback of the lwb's zio[*].
3070 * * Actually, the waiters are signaled in the zio completion
3071 * callback of the root zio for the DKIOCFLUSHWRITECACHE commands
3072 * that are sent to the vdevs upon completion of the lwb zio.
3074 * 2. When the itxs are inserted into the ZIL's queue of uncommitted
3075 * itxs, the order in which they are inserted is preserved[*]; as
3076 * itxs are added to the queue, they are added to the tail of
3077 * in-memory linked lists.
3079 * When committing the itxs to lwbs (to be written to disk), they
3080 * are committed in the same order in which the itxs were added to
3081 * the uncommitted queue's linked list(s); i.e. the linked list of
3082 * itxs to commit is traversed from head to tail, and each itx is
3083 * committed to an lwb in that order.
3087 * - the order of "sync" itxs is preserved w.r.t. other
3088 * "sync" itxs, regardless of the corresponding objects.
3089 * - the order of "async" itxs is preserved w.r.t. other
3090 * "async" itxs corresponding to the same object.
3091 * - the order of "async" itxs is *not* preserved w.r.t. other
3092 * "async" itxs corresponding to different objects.
3093 * - the order of "sync" itxs w.r.t. "async" itxs (or vice
3094 * versa) is *not* preserved, even for itxs that correspond
3095 * to the same object.
3097 * For more details, see: zil_itx_assign(), zil_async_to_sync(),
3098 * zil_get_commit_list(), and zil_process_commit_list().
3100 * 3. The lwbs represent a linked list of blocks on disk. Thus, any
3101 * lwb cannot be considered committed to stable storage, until its
3102 * "previous" lwb is also committed to stable storage. This fact,
3103 * coupled with the fact described above, means that itxs are
3104 * committed in (roughly) the order in which they were generated.
3105 * This is essential because itxs are dependent on prior itxs.
3106 * Thus, we *must not* deem an itx as being committed to stable
3107 * storage, until *all* prior itxs have also been committed to
3110 * To enforce this ordering of lwb zio's, while still leveraging as
3111 * much of the underlying storage performance as possible, we rely
3112 * on two fundamental concepts:
3114 * 1. The creation and issuance of lwb zio's is protected by
3115 * the zilog's "zl_issuer_lock", which ensures only a single
3116 * thread is creating and/or issuing lwb's at a time
3117 * 2. The "previous" lwb is a child of the "current" lwb
3118 * (leveraging the zio parent-child dependency graph)
3120 * By relying on this parent-child zio relationship, we can have
3121 * many lwb zio's concurrently issued to the underlying storage,
3122 * but the order in which they complete will be the same order in
3123 * which they were created.
3126 zil_commit(zilog_t *zilog, uint64_t foid)
3129 * We should never attempt to call zil_commit on a snapshot for
3130 * a couple of reasons:
3132 * 1. A snapshot may never be modified, thus it cannot have any
3133 * in-flight itxs that would have modified the dataset.
3135 * 2. By design, when zil_commit() is called, a commit itx will
3136 * be assigned to this zilog; as a result, the zilog will be
3137 * dirtied. We must not dirty the zilog of a snapshot; there's
3138 * checks in the code that enforce this invariant, and will
3139 * cause a panic if it's not upheld.
3141 ASSERT3B(dmu_objset_is_snapshot(zilog->zl_os), ==, B_FALSE);
3143 if (zilog->zl_sync == ZFS_SYNC_DISABLED)
3146 if (!spa_writeable(zilog->zl_spa)) {
3148 * If the SPA is not writable, there should never be any
3149 * pending itxs waiting to be committed to disk. If that
3150 * weren't true, we'd skip writing those itxs out, and
3151 * would break the semantics of zil_commit(); thus, we're
3152 * verifying that truth before we return to the caller.
3154 ASSERT(list_is_empty(&zilog->zl_lwb_list));
3155 ASSERT3P(zilog->zl_last_lwb_opened, ==, NULL);
3156 for (int i = 0; i < TXG_SIZE; i++)
3157 ASSERT3P(zilog->zl_itxg[i].itxg_itxs, ==, NULL);
3162 * If the ZIL is suspended, we don't want to dirty it by calling
3163 * zil_commit_itx_assign() below, nor can we write out
3164 * lwbs like would be done in zil_commit_write(). Thus, we
3165 * simply rely on txg_wait_synced() to maintain the necessary
3166 * semantics, and avoid calling those functions altogether.
3168 if (zilog->zl_suspend > 0) {
3169 txg_wait_synced(zilog->zl_dmu_pool, 0);
3173 zil_commit_impl(zilog, foid);
3177 zil_commit_impl(zilog_t *zilog, uint64_t foid)
3179 ZIL_STAT_BUMP(zilog, zil_commit_count);
3182 * Move the "async" itxs for the specified foid to the "sync"
3183 * queues, such that they will be later committed (or skipped)
3184 * to an lwb when zil_process_commit_list() is called.
3186 * Since these "async" itxs must be committed prior to this
3187 * call to zil_commit returning, we must perform this operation
3188 * before we call zil_commit_itx_assign().
3190 zil_async_to_sync(zilog, foid);
3193 * We allocate a new "waiter" structure which will initially be
3194 * linked to the commit itx using the itx's "itx_private" field.
3195 * Since the commit itx doesn't represent any on-disk state,
3196 * when it's committed to an lwb, rather than copying the its
3197 * lr_t into the lwb's buffer, the commit itx's "waiter" will be
3198 * added to the lwb's list of waiters. Then, when the lwb is
3199 * committed to stable storage, each waiter in the lwb's list of
3200 * waiters will be marked "done", and signalled.
3202 * We must create the waiter and assign the commit itx prior to
3203 * calling zil_commit_writer(), or else our specific commit itx
3204 * is not guaranteed to be committed to an lwb prior to calling
3205 * zil_commit_waiter().
3207 zil_commit_waiter_t *zcw = zil_alloc_commit_waiter();
3208 zil_commit_itx_assign(zilog, zcw);
3210 zil_commit_writer(zilog, zcw);
3211 zil_commit_waiter(zilog, zcw);
3213 if (zcw->zcw_zio_error != 0) {
3215 * If there was an error writing out the ZIL blocks that
3216 * this thread is waiting on, then we fallback to
3217 * relying on spa_sync() to write out the data this
3218 * thread is waiting on. Obviously this has performance
3219 * implications, but the expectation is for this to be
3220 * an exceptional case, and shouldn't occur often.
3222 DTRACE_PROBE2(zil__commit__io__error,
3223 zilog_t *, zilog, zil_commit_waiter_t *, zcw);
3224 txg_wait_synced(zilog->zl_dmu_pool, 0);
3227 zil_free_commit_waiter(zcw);
3231 * Called in syncing context to free committed log blocks and update log header.
3234 zil_sync(zilog_t *zilog, dmu_tx_t *tx)
3236 zil_header_t *zh = zil_header_in_syncing_context(zilog);
3237 uint64_t txg = dmu_tx_get_txg(tx);
3238 spa_t *spa = zilog->zl_spa;
3239 uint64_t *replayed_seq = &zilog->zl_replayed_seq[txg & TXG_MASK];
3243 * We don't zero out zl_destroy_txg, so make sure we don't try
3244 * to destroy it twice.
3246 if (spa_sync_pass(spa) != 1)
3249 zil_lwb_flush_wait_all(zilog, txg);
3251 mutex_enter(&zilog->zl_lock);
3253 ASSERT(zilog->zl_stop_sync == 0);
3255 if (*replayed_seq != 0) {
3256 ASSERT(zh->zh_replay_seq < *replayed_seq);
3257 zh->zh_replay_seq = *replayed_seq;
3261 if (zilog->zl_destroy_txg == txg) {
3262 blkptr_t blk = zh->zh_log;
3263 dsl_dataset_t *ds = dmu_objset_ds(zilog->zl_os);
3265 ASSERT(list_head(&zilog->zl_lwb_list) == NULL);
3267 memset(zh, 0, sizeof (zil_header_t));
3268 memset(zilog->zl_replayed_seq, 0,
3269 sizeof (zilog->zl_replayed_seq));
3271 if (zilog->zl_keep_first) {
3273 * If this block was part of log chain that couldn't
3274 * be claimed because a device was missing during
3275 * zil_claim(), but that device later returns,
3276 * then this block could erroneously appear valid.
3277 * To guard against this, assign a new GUID to the new
3278 * log chain so it doesn't matter what blk points to.
3280 zil_init_log_chain(zilog, &blk);
3284 * A destroyed ZIL chain can't contain any TX_SETSAXATTR
3285 * records. So, deactivate the feature for this dataset.
3286 * We activate it again when we start a new ZIL chain.
3288 if (dsl_dataset_feature_is_active(ds,
3289 SPA_FEATURE_ZILSAXATTR))
3290 dsl_dataset_deactivate_feature(ds,
3291 SPA_FEATURE_ZILSAXATTR, tx);
3295 while ((lwb = list_head(&zilog->zl_lwb_list)) != NULL) {
3296 zh->zh_log = lwb->lwb_blk;
3297 if (lwb->lwb_buf != NULL || lwb->lwb_max_txg > txg)
3299 list_remove(&zilog->zl_lwb_list, lwb);
3300 zio_free(spa, txg, &lwb->lwb_blk);
3301 zil_free_lwb(zilog, lwb);
3304 * If we don't have anything left in the lwb list then
3305 * we've had an allocation failure and we need to zero
3306 * out the zil_header blkptr so that we don't end
3307 * up freeing the same block twice.
3309 if (list_head(&zilog->zl_lwb_list) == NULL)
3310 BP_ZERO(&zh->zh_log);
3314 * Remove fastwrite on any blocks that have been pre-allocated for
3315 * the next commit. This prevents fastwrite counter pollution by
3316 * unused, long-lived LWBs.
3318 for (; lwb != NULL; lwb = list_next(&zilog->zl_lwb_list, lwb)) {
3319 if (lwb->lwb_fastwrite && !lwb->lwb_write_zio) {
3320 metaslab_fastwrite_unmark(zilog->zl_spa, &lwb->lwb_blk);
3321 lwb->lwb_fastwrite = 0;
3325 mutex_exit(&zilog->zl_lock);
3329 zil_lwb_cons(void *vbuf, void *unused, int kmflag)
3331 (void) unused, (void) kmflag;
3333 list_create(&lwb->lwb_itxs, sizeof (itx_t), offsetof(itx_t, itx_node));
3334 list_create(&lwb->lwb_waiters, sizeof (zil_commit_waiter_t),
3335 offsetof(zil_commit_waiter_t, zcw_node));
3336 avl_create(&lwb->lwb_vdev_tree, zil_lwb_vdev_compare,
3337 sizeof (zil_vdev_node_t), offsetof(zil_vdev_node_t, zv_node));
3338 mutex_init(&lwb->lwb_vdev_lock, NULL, MUTEX_DEFAULT, NULL);
3343 zil_lwb_dest(void *vbuf, void *unused)
3347 mutex_destroy(&lwb->lwb_vdev_lock);
3348 avl_destroy(&lwb->lwb_vdev_tree);
3349 list_destroy(&lwb->lwb_waiters);
3350 list_destroy(&lwb->lwb_itxs);
3356 zil_lwb_cache = kmem_cache_create("zil_lwb_cache",
3357 sizeof (lwb_t), 0, zil_lwb_cons, zil_lwb_dest, NULL, NULL, NULL, 0);
3359 zil_zcw_cache = kmem_cache_create("zil_zcw_cache",
3360 sizeof (zil_commit_waiter_t), 0, NULL, NULL, NULL, NULL, NULL, 0);
3362 zil_sums_init(&zil_sums_global);
3363 zil_kstats_global = kstat_create("zfs", 0, "zil", "misc",
3364 KSTAT_TYPE_NAMED, sizeof (zil_stats) / sizeof (kstat_named_t),
3365 KSTAT_FLAG_VIRTUAL);
3367 if (zil_kstats_global != NULL) {
3368 zil_kstats_global->ks_data = &zil_stats;
3369 zil_kstats_global->ks_update = zil_kstats_global_update;
3370 zil_kstats_global->ks_private = NULL;
3371 kstat_install(zil_kstats_global);
3378 kmem_cache_destroy(zil_zcw_cache);
3379 kmem_cache_destroy(zil_lwb_cache);
3381 if (zil_kstats_global != NULL) {
3382 kstat_delete(zil_kstats_global);
3383 zil_kstats_global = NULL;
3386 zil_sums_fini(&zil_sums_global);
3390 zil_set_sync(zilog_t *zilog, uint64_t sync)
3392 zilog->zl_sync = sync;
3396 zil_set_logbias(zilog_t *zilog, uint64_t logbias)
3398 zilog->zl_logbias = logbias;
3402 zil_alloc(objset_t *os, zil_header_t *zh_phys)
3406 zilog = kmem_zalloc(sizeof (zilog_t), KM_SLEEP);
3408 zilog->zl_header = zh_phys;
3410 zilog->zl_spa = dmu_objset_spa(os);
3411 zilog->zl_dmu_pool = dmu_objset_pool(os);
3412 zilog->zl_destroy_txg = TXG_INITIAL - 1;
3413 zilog->zl_logbias = dmu_objset_logbias(os);
3414 zilog->zl_sync = dmu_objset_syncprop(os);
3415 zilog->zl_dirty_max_txg = 0;
3416 zilog->zl_last_lwb_opened = NULL;
3417 zilog->zl_last_lwb_latency = 0;
3418 zilog->zl_max_block_size = zil_maxblocksize;
3420 mutex_init(&zilog->zl_lock, NULL, MUTEX_DEFAULT, NULL);
3421 mutex_init(&zilog->zl_issuer_lock, NULL, MUTEX_DEFAULT, NULL);
3422 mutex_init(&zilog->zl_lwb_io_lock, NULL, MUTEX_DEFAULT, NULL);
3424 for (int i = 0; i < TXG_SIZE; i++) {
3425 mutex_init(&zilog->zl_itxg[i].itxg_lock, NULL,
3426 MUTEX_DEFAULT, NULL);
3429 list_create(&zilog->zl_lwb_list, sizeof (lwb_t),
3430 offsetof(lwb_t, lwb_node));
3432 list_create(&zilog->zl_itx_commit_list, sizeof (itx_t),
3433 offsetof(itx_t, itx_node));
3435 cv_init(&zilog->zl_cv_suspend, NULL, CV_DEFAULT, NULL);
3436 cv_init(&zilog->zl_lwb_io_cv, NULL, CV_DEFAULT, NULL);
3442 zil_free(zilog_t *zilog)
3446 zilog->zl_stop_sync = 1;
3448 ASSERT0(zilog->zl_suspend);
3449 ASSERT0(zilog->zl_suspending);
3451 ASSERT(list_is_empty(&zilog->zl_lwb_list));
3452 list_destroy(&zilog->zl_lwb_list);
3454 ASSERT(list_is_empty(&zilog->zl_itx_commit_list));
3455 list_destroy(&zilog->zl_itx_commit_list);
3457 for (i = 0; i < TXG_SIZE; i++) {
3459 * It's possible for an itx to be generated that doesn't dirty
3460 * a txg (e.g. ztest TX_TRUNCATE). So there's no zil_clean()
3461 * callback to remove the entry. We remove those here.
3463 * Also free up the ziltest itxs.
3465 if (zilog->zl_itxg[i].itxg_itxs)
3466 zil_itxg_clean(zilog->zl_itxg[i].itxg_itxs);
3467 mutex_destroy(&zilog->zl_itxg[i].itxg_lock);
3470 mutex_destroy(&zilog->zl_issuer_lock);
3471 mutex_destroy(&zilog->zl_lock);
3472 mutex_destroy(&zilog->zl_lwb_io_lock);
3474 cv_destroy(&zilog->zl_cv_suspend);
3475 cv_destroy(&zilog->zl_lwb_io_cv);
3477 kmem_free(zilog, sizeof (zilog_t));
3481 * Open an intent log.
3484 zil_open(objset_t *os, zil_get_data_t *get_data, zil_sums_t *zil_sums)
3486 zilog_t *zilog = dmu_objset_zil(os);
3488 ASSERT3P(zilog->zl_get_data, ==, NULL);
3489 ASSERT3P(zilog->zl_last_lwb_opened, ==, NULL);
3490 ASSERT(list_is_empty(&zilog->zl_lwb_list));
3492 zilog->zl_get_data = get_data;
3493 zilog->zl_sums = zil_sums;
3499 * Close an intent log.
3502 zil_close(zilog_t *zilog)
3507 if (!dmu_objset_is_snapshot(zilog->zl_os)) {
3508 zil_commit(zilog, 0);
3510 ASSERT3P(list_tail(&zilog->zl_lwb_list), ==, NULL);
3511 ASSERT0(zilog->zl_dirty_max_txg);
3512 ASSERT3B(zilog_is_dirty(zilog), ==, B_FALSE);
3515 mutex_enter(&zilog->zl_lock);
3516 lwb = list_tail(&zilog->zl_lwb_list);
3518 txg = zilog->zl_dirty_max_txg;
3520 txg = MAX(zilog->zl_dirty_max_txg, lwb->lwb_max_txg);
3521 mutex_exit(&zilog->zl_lock);
3524 * zl_lwb_max_issued_txg may be larger than lwb_max_txg. It depends
3525 * on the time when the dmu_tx transaction is assigned in
3526 * zil_lwb_write_issue().
3528 mutex_enter(&zilog->zl_lwb_io_lock);
3529 txg = MAX(zilog->zl_lwb_max_issued_txg, txg);
3530 mutex_exit(&zilog->zl_lwb_io_lock);
3533 * We need to use txg_wait_synced() to wait until that txg is synced.
3534 * zil_sync() will guarantee all lwbs up to that txg have been
3535 * written out, flushed, and cleaned.
3538 txg_wait_synced(zilog->zl_dmu_pool, txg);
3540 if (zilog_is_dirty(zilog))
3541 zfs_dbgmsg("zil (%px) is dirty, txg %llu", zilog,
3543 if (txg < spa_freeze_txg(zilog->zl_spa))
3544 VERIFY(!zilog_is_dirty(zilog));
3546 zilog->zl_get_data = NULL;
3549 * We should have only one lwb left on the list; remove it now.
3551 mutex_enter(&zilog->zl_lock);
3552 lwb = list_head(&zilog->zl_lwb_list);
3554 ASSERT3P(lwb, ==, list_tail(&zilog->zl_lwb_list));
3555 ASSERT3S(lwb->lwb_state, !=, LWB_STATE_ISSUED);
3557 if (lwb->lwb_fastwrite)
3558 metaslab_fastwrite_unmark(zilog->zl_spa, &lwb->lwb_blk);
3560 list_remove(&zilog->zl_lwb_list, lwb);
3561 zio_buf_free(lwb->lwb_buf, lwb->lwb_sz);
3562 zil_free_lwb(zilog, lwb);
3564 mutex_exit(&zilog->zl_lock);
3567 static const char *suspend_tag = "zil suspending";
3570 * Suspend an intent log. While in suspended mode, we still honor
3571 * synchronous semantics, but we rely on txg_wait_synced() to do it.
3572 * On old version pools, we suspend the log briefly when taking a
3573 * snapshot so that it will have an empty intent log.
3575 * Long holds are not really intended to be used the way we do here --
3576 * held for such a short time. A concurrent caller of dsl_dataset_long_held()
3577 * could fail. Therefore we take pains to only put a long hold if it is
3578 * actually necessary. Fortunately, it will only be necessary if the
3579 * objset is currently mounted (or the ZVOL equivalent). In that case it
3580 * will already have a long hold, so we are not really making things any worse.
3582 * Ideally, we would locate the existing long-holder (i.e. the zfsvfs_t or
3583 * zvol_state_t), and use their mechanism to prevent their hold from being
3584 * dropped (e.g. VFS_HOLD()). However, that would be even more pain for
3587 * if cookiep == NULL, this does both the suspend & resume.
3588 * Otherwise, it returns with the dataset "long held", and the cookie
3589 * should be passed into zil_resume().
3592 zil_suspend(const char *osname, void **cookiep)
3596 const zil_header_t *zh;
3599 error = dmu_objset_hold(osname, suspend_tag, &os);
3602 zilog = dmu_objset_zil(os);
3604 mutex_enter(&zilog->zl_lock);
3605 zh = zilog->zl_header;
3607 if (zh->zh_flags & ZIL_REPLAY_NEEDED) { /* unplayed log */
3608 mutex_exit(&zilog->zl_lock);
3609 dmu_objset_rele(os, suspend_tag);
3610 return (SET_ERROR(EBUSY));
3614 * Don't put a long hold in the cases where we can avoid it. This
3615 * is when there is no cookie so we are doing a suspend & resume
3616 * (i.e. called from zil_vdev_offline()), and there's nothing to do
3617 * for the suspend because it's already suspended, or there's no ZIL.
3619 if (cookiep == NULL && !zilog->zl_suspending &&
3620 (zilog->zl_suspend > 0 || BP_IS_HOLE(&zh->zh_log))) {
3621 mutex_exit(&zilog->zl_lock);
3622 dmu_objset_rele(os, suspend_tag);
3626 dsl_dataset_long_hold(dmu_objset_ds(os), suspend_tag);
3627 dsl_pool_rele(dmu_objset_pool(os), suspend_tag);
3629 zilog->zl_suspend++;
3631 if (zilog->zl_suspend > 1) {
3633 * Someone else is already suspending it.
3634 * Just wait for them to finish.
3637 while (zilog->zl_suspending)
3638 cv_wait(&zilog->zl_cv_suspend, &zilog->zl_lock);
3639 mutex_exit(&zilog->zl_lock);
3641 if (cookiep == NULL)
3649 * If there is no pointer to an on-disk block, this ZIL must not
3650 * be active (e.g. filesystem not mounted), so there's nothing
3653 if (BP_IS_HOLE(&zh->zh_log)) {
3654 ASSERT(cookiep != NULL); /* fast path already handled */
3657 mutex_exit(&zilog->zl_lock);
3662 * The ZIL has work to do. Ensure that the associated encryption
3663 * key will remain mapped while we are committing the log by
3664 * grabbing a reference to it. If the key isn't loaded we have no
3665 * choice but to return an error until the wrapping key is loaded.
3667 if (os->os_encrypted &&
3668 dsl_dataset_create_key_mapping(dmu_objset_ds(os)) != 0) {
3669 zilog->zl_suspend--;
3670 mutex_exit(&zilog->zl_lock);
3671 dsl_dataset_long_rele(dmu_objset_ds(os), suspend_tag);
3672 dsl_dataset_rele(dmu_objset_ds(os), suspend_tag);
3673 return (SET_ERROR(EACCES));
3676 zilog->zl_suspending = B_TRUE;
3677 mutex_exit(&zilog->zl_lock);
3680 * We need to use zil_commit_impl to ensure we wait for all
3681 * LWB_STATE_OPENED and LWB_STATE_ISSUED lwbs to be committed
3682 * to disk before proceeding. If we used zil_commit instead, it
3683 * would just call txg_wait_synced(), because zl_suspend is set.
3684 * txg_wait_synced() doesn't wait for these lwb's to be
3685 * LWB_STATE_FLUSH_DONE before returning.
3687 zil_commit_impl(zilog, 0);
3690 * Now that we've ensured all lwb's are LWB_STATE_FLUSH_DONE, we
3691 * use txg_wait_synced() to ensure the data from the zilog has
3692 * migrated to the main pool before calling zil_destroy().
3694 txg_wait_synced(zilog->zl_dmu_pool, 0);
3696 zil_destroy(zilog, B_FALSE);
3698 mutex_enter(&zilog->zl_lock);
3699 zilog->zl_suspending = B_FALSE;
3700 cv_broadcast(&zilog->zl_cv_suspend);
3701 mutex_exit(&zilog->zl_lock);
3703 if (os->os_encrypted)
3704 dsl_dataset_remove_key_mapping(dmu_objset_ds(os));
3706 if (cookiep == NULL)
3714 zil_resume(void *cookie)
3716 objset_t *os = cookie;
3717 zilog_t *zilog = dmu_objset_zil(os);
3719 mutex_enter(&zilog->zl_lock);
3720 ASSERT(zilog->zl_suspend != 0);
3721 zilog->zl_suspend--;
3722 mutex_exit(&zilog->zl_lock);
3723 dsl_dataset_long_rele(dmu_objset_ds(os), suspend_tag);
3724 dsl_dataset_rele(dmu_objset_ds(os), suspend_tag);
3727 typedef struct zil_replay_arg {
3728 zil_replay_func_t *const *zr_replay;
3730 boolean_t zr_byteswap;
3735 zil_replay_error(zilog_t *zilog, const lr_t *lr, int error)
3737 char name[ZFS_MAX_DATASET_NAME_LEN];
3739 zilog->zl_replaying_seq--; /* didn't actually replay this one */
3741 dmu_objset_name(zilog->zl_os, name);
3743 cmn_err(CE_WARN, "ZFS replay transaction error %d, "
3744 "dataset %s, seq 0x%llx, txtype %llu %s\n", error, name,
3745 (u_longlong_t)lr->lrc_seq,
3746 (u_longlong_t)(lr->lrc_txtype & ~TX_CI),
3747 (lr->lrc_txtype & TX_CI) ? "CI" : "");
3753 zil_replay_log_record(zilog_t *zilog, const lr_t *lr, void *zra,
3756 zil_replay_arg_t *zr = zra;
3757 const zil_header_t *zh = zilog->zl_header;
3758 uint64_t reclen = lr->lrc_reclen;
3759 uint64_t txtype = lr->lrc_txtype;
3762 zilog->zl_replaying_seq = lr->lrc_seq;
3764 if (lr->lrc_seq <= zh->zh_replay_seq) /* already replayed */
3767 if (lr->lrc_txg < claim_txg) /* already committed */
3770 /* Strip case-insensitive bit, still present in log record */
3773 if (txtype == 0 || txtype >= TX_MAX_TYPE)
3774 return (zil_replay_error(zilog, lr, EINVAL));
3777 * If this record type can be logged out of order, the object
3778 * (lr_foid) may no longer exist. That's legitimate, not an error.
3780 if (TX_OOO(txtype)) {
3781 error = dmu_object_info(zilog->zl_os,
3782 LR_FOID_GET_OBJ(((lr_ooo_t *)lr)->lr_foid), NULL);
3783 if (error == ENOENT || error == EEXIST)
3788 * Make a copy of the data so we can revise and extend it.
3790 memcpy(zr->zr_lr, lr, reclen);
3793 * If this is a TX_WRITE with a blkptr, suck in the data.
3795 if (txtype == TX_WRITE && reclen == sizeof (lr_write_t)) {
3796 error = zil_read_log_data(zilog, (lr_write_t *)lr,
3797 zr->zr_lr + reclen);
3799 return (zil_replay_error(zilog, lr, error));
3803 * The log block containing this lr may have been byteswapped
3804 * so that we can easily examine common fields like lrc_txtype.
3805 * However, the log is a mix of different record types, and only the
3806 * replay vectors know how to byteswap their records. Therefore, if
3807 * the lr was byteswapped, undo it before invoking the replay vector.
3809 if (zr->zr_byteswap)
3810 byteswap_uint64_array(zr->zr_lr, reclen);
3813 * We must now do two things atomically: replay this log record,
3814 * and update the log header sequence number to reflect the fact that
3815 * we did so. At the end of each replay function the sequence number
3816 * is updated if we are in replay mode.
3818 error = zr->zr_replay[txtype](zr->zr_arg, zr->zr_lr, zr->zr_byteswap);
3821 * The DMU's dnode layer doesn't see removes until the txg
3822 * commits, so a subsequent claim can spuriously fail with
3823 * EEXIST. So if we receive any error we try syncing out
3824 * any removes then retry the transaction. Note that we
3825 * specify B_FALSE for byteswap now, so we don't do it twice.
3827 txg_wait_synced(spa_get_dsl(zilog->zl_spa), 0);
3828 error = zr->zr_replay[txtype](zr->zr_arg, zr->zr_lr, B_FALSE);
3830 return (zil_replay_error(zilog, lr, error));
3836 zil_incr_blks(zilog_t *zilog, const blkptr_t *bp, void *arg, uint64_t claim_txg)
3838 (void) bp, (void) arg, (void) claim_txg;
3840 zilog->zl_replay_blks++;
3846 * If this dataset has a non-empty intent log, replay it and destroy it.
3849 zil_replay(objset_t *os, void *arg,
3850 zil_replay_func_t *const replay_func[TX_MAX_TYPE])
3852 zilog_t *zilog = dmu_objset_zil(os);
3853 const zil_header_t *zh = zilog->zl_header;
3854 zil_replay_arg_t zr;
3856 if ((zh->zh_flags & ZIL_REPLAY_NEEDED) == 0) {
3857 zil_destroy(zilog, B_TRUE);
3861 zr.zr_replay = replay_func;
3863 zr.zr_byteswap = BP_SHOULD_BYTESWAP(&zh->zh_log);
3864 zr.zr_lr = vmem_alloc(2 * SPA_MAXBLOCKSIZE, KM_SLEEP);
3867 * Wait for in-progress removes to sync before starting replay.
3869 txg_wait_synced(zilog->zl_dmu_pool, 0);
3871 zilog->zl_replay = B_TRUE;
3872 zilog->zl_replay_time = ddi_get_lbolt();
3873 ASSERT(zilog->zl_replay_blks == 0);
3874 (void) zil_parse(zilog, zil_incr_blks, zil_replay_log_record, &zr,
3875 zh->zh_claim_txg, B_TRUE);
3876 vmem_free(zr.zr_lr, 2 * SPA_MAXBLOCKSIZE);
3878 zil_destroy(zilog, B_FALSE);
3879 txg_wait_synced(zilog->zl_dmu_pool, zilog->zl_destroy_txg);
3880 zilog->zl_replay = B_FALSE;
3884 zil_replaying(zilog_t *zilog, dmu_tx_t *tx)
3886 if (zilog->zl_sync == ZFS_SYNC_DISABLED)
3889 if (zilog->zl_replay) {
3890 dsl_dataset_dirty(dmu_objset_ds(zilog->zl_os), tx);
3891 zilog->zl_replayed_seq[dmu_tx_get_txg(tx) & TXG_MASK] =
3892 zilog->zl_replaying_seq;
3900 zil_reset(const char *osname, void *arg)
3904 int error = zil_suspend(osname, NULL);
3905 /* EACCES means crypto key not loaded */
3906 if ((error == EACCES) || (error == EBUSY))
3907 return (SET_ERROR(error));
3909 return (SET_ERROR(EEXIST));
3913 EXPORT_SYMBOL(zil_alloc);
3914 EXPORT_SYMBOL(zil_free);
3915 EXPORT_SYMBOL(zil_open);
3916 EXPORT_SYMBOL(zil_close);
3917 EXPORT_SYMBOL(zil_replay);
3918 EXPORT_SYMBOL(zil_replaying);
3919 EXPORT_SYMBOL(zil_destroy);
3920 EXPORT_SYMBOL(zil_destroy_sync);
3921 EXPORT_SYMBOL(zil_itx_create);
3922 EXPORT_SYMBOL(zil_itx_destroy);
3923 EXPORT_SYMBOL(zil_itx_assign);
3924 EXPORT_SYMBOL(zil_commit);
3925 EXPORT_SYMBOL(zil_claim);
3926 EXPORT_SYMBOL(zil_check_log_chain);
3927 EXPORT_SYMBOL(zil_sync);
3928 EXPORT_SYMBOL(zil_clean);
3929 EXPORT_SYMBOL(zil_suspend);
3930 EXPORT_SYMBOL(zil_resume);
3931 EXPORT_SYMBOL(zil_lwb_add_block);
3932 EXPORT_SYMBOL(zil_bp_tree_add);
3933 EXPORT_SYMBOL(zil_set_sync);
3934 EXPORT_SYMBOL(zil_set_logbias);
3935 EXPORT_SYMBOL(zil_sums_init);
3936 EXPORT_SYMBOL(zil_sums_fini);
3937 EXPORT_SYMBOL(zil_kstat_values_update);
3939 ZFS_MODULE_PARAM(zfs, zfs_, commit_timeout_pct, UINT, ZMOD_RW,
3940 "ZIL block open timeout percentage");
3942 ZFS_MODULE_PARAM(zfs_zil, zil_, replay_disable, INT, ZMOD_RW,
3943 "Disable intent logging replay");
3945 ZFS_MODULE_PARAM(zfs_zil, zil_, nocacheflush, INT, ZMOD_RW,
3946 "Disable ZIL cache flushes");
3948 ZFS_MODULE_PARAM(zfs_zil, zil_, slog_bulk, ULONG, ZMOD_RW,
3949 "Limit in bytes slog sync writes per commit");
3951 ZFS_MODULE_PARAM(zfs_zil, zil_, maxblocksize, UINT, ZMOD_RW,
3952 "Limit in bytes of ZIL log block size");