4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
13 * When distributing Covered Code, include this CDDL HEADER in each
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, 2017 by Delphix. All rights reserved.
24 * Copyright (c) 2014 Integros [integros.com]
27 /* Portions Copyright 2010 Robert Milkowski */
29 #include <sys/zfs_context.h>
31 #include <sys/spa_impl.h>
36 #include <sys/resource.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>
46 * The ZFS Intent Log (ZIL) saves "transaction records" (itxs) of system
47 * calls that change the file system. Each itx has enough information to
48 * be able to replay them after a system crash, power loss, or
49 * equivalent failure mode. These are stored in memory until either:
51 * 1. they are committed to the pool by the DMU transaction group
52 * (txg), at which point they can be discarded; or
53 * 2. they are committed to the on-disk ZIL for the dataset being
54 * modified (e.g. due to an fsync, O_DSYNC, or other synchronous
57 * In the event of a crash or power loss, the itxs contained by each
58 * dataset's on-disk ZIL will be replayed when that dataset is first
59 * instantianted (e.g. if the dataset is a normal fileystem, when it is
62 * As hinted at above, there is one ZIL per dataset (both the in-memory
63 * representation, and the on-disk representation). The on-disk format
64 * consists of 3 parts:
66 * - a single, per-dataset, ZIL header; which points to a chain of
67 * - zero or more ZIL blocks; each of which contains
68 * - zero or more ZIL records
70 * A ZIL record holds the information necessary to replay a single
71 * system call transaction. A ZIL block can hold many ZIL records, and
72 * the blocks are chained together, similarly to a singly linked list.
74 * Each ZIL block contains a block pointer (blkptr_t) to the next ZIL
75 * block in the chain, and the ZIL header points to the first block in
78 * Note, there is not a fixed place in the pool to hold these ZIL
79 * blocks; they are dynamically allocated and freed as needed from the
80 * blocks available on the pool, though they can be preferentially
81 * allocated from a dedicated "log" vdev.
85 * This controls the amount of time that a ZIL block (lwb) will remain
86 * "open" when it isn't "full", and it has a thread waiting for it to be
87 * committed to stable storage. Please refer to the zil_commit_waiter()
88 * function (and the comments within it) for more details.
90 int zfs_commit_timeout_pct
= 5;
93 * Disable intent logging replay. This global ZIL switch affects all pools.
95 int zil_replay_disable
= 0;
98 * Tunable parameter for debugging or performance analysis. Setting
99 * zfs_nocacheflush will cause corruption on power loss if a volatile
100 * out-of-order write cache is enabled.
102 boolean_t zfs_nocacheflush
= B_FALSE
;
105 * Limit SLOG write size per commit executed with synchronous priority.
106 * Any writes above that will be executed with lower (asynchronous) priority
107 * to limit potential SLOG device abuse by single active ZIL writer.
109 uint64_t zil_slog_bulk
= 768 * 1024;
111 static kmem_cache_t
*zil_lwb_cache
;
112 static kmem_cache_t
*zil_zcw_cache
;
114 static void zil_async_to_sync(zilog_t
*zilog
, uint64_t foid
);
116 #define LWB_EMPTY(lwb) ((BP_GET_LSIZE(&lwb->lwb_blk) - \
117 sizeof (zil_chain_t)) == (lwb->lwb_sz - lwb->lwb_nused))
120 zil_bp_compare(const void *x1
, const void *x2
)
122 const dva_t
*dva1
= &((zil_bp_node_t
*)x1
)->zn_dva
;
123 const dva_t
*dva2
= &((zil_bp_node_t
*)x2
)->zn_dva
;
125 if (DVA_GET_VDEV(dva1
) < DVA_GET_VDEV(dva2
))
127 if (DVA_GET_VDEV(dva1
) > DVA_GET_VDEV(dva2
))
130 if (DVA_GET_OFFSET(dva1
) < DVA_GET_OFFSET(dva2
))
132 if (DVA_GET_OFFSET(dva1
) > DVA_GET_OFFSET(dva2
))
139 zil_bp_tree_init(zilog_t
*zilog
)
141 avl_create(&zilog
->zl_bp_tree
, zil_bp_compare
,
142 sizeof (zil_bp_node_t
), offsetof(zil_bp_node_t
, zn_node
));
146 zil_bp_tree_fini(zilog_t
*zilog
)
148 avl_tree_t
*t
= &zilog
->zl_bp_tree
;
152 while ((zn
= avl_destroy_nodes(t
, &cookie
)) != NULL
)
153 kmem_free(zn
, sizeof (zil_bp_node_t
));
159 zil_bp_tree_add(zilog_t
*zilog
, const blkptr_t
*bp
)
161 avl_tree_t
*t
= &zilog
->zl_bp_tree
;
166 if (BP_IS_EMBEDDED(bp
))
169 dva
= BP_IDENTITY(bp
);
171 if (avl_find(t
, dva
, &where
) != NULL
)
172 return (SET_ERROR(EEXIST
));
174 zn
= kmem_alloc(sizeof (zil_bp_node_t
), KM_SLEEP
);
176 avl_insert(t
, zn
, where
);
181 static zil_header_t
*
182 zil_header_in_syncing_context(zilog_t
*zilog
)
184 return ((zil_header_t
*)zilog
->zl_header
);
188 zil_init_log_chain(zilog_t
*zilog
, blkptr_t
*bp
)
190 zio_cksum_t
*zc
= &bp
->blk_cksum
;
192 zc
->zc_word
[ZIL_ZC_GUID_0
] = spa_get_random(-1ULL);
193 zc
->zc_word
[ZIL_ZC_GUID_1
] = spa_get_random(-1ULL);
194 zc
->zc_word
[ZIL_ZC_OBJSET
] = dmu_objset_id(zilog
->zl_os
);
195 zc
->zc_word
[ZIL_ZC_SEQ
] = 1ULL;
199 * Read a log block and make sure it's valid.
202 zil_read_log_block(zilog_t
*zilog
, const blkptr_t
*bp
, blkptr_t
*nbp
, void *dst
,
205 enum zio_flag zio_flags
= ZIO_FLAG_CANFAIL
;
206 arc_flags_t aflags
= ARC_FLAG_WAIT
;
207 arc_buf_t
*abuf
= NULL
;
211 if (zilog
->zl_header
->zh_claim_txg
== 0)
212 zio_flags
|= ZIO_FLAG_SPECULATIVE
| ZIO_FLAG_SCRUB
;
214 if (!(zilog
->zl_header
->zh_flags
& ZIL_CLAIM_LR_SEQ_VALID
))
215 zio_flags
|= ZIO_FLAG_SPECULATIVE
;
217 SET_BOOKMARK(&zb
, bp
->blk_cksum
.zc_word
[ZIL_ZC_OBJSET
],
218 ZB_ZIL_OBJECT
, ZB_ZIL_LEVEL
, bp
->blk_cksum
.zc_word
[ZIL_ZC_SEQ
]);
220 error
= arc_read(NULL
, zilog
->zl_spa
, bp
, arc_getbuf_func
, &abuf
,
221 ZIO_PRIORITY_SYNC_READ
, zio_flags
, &aflags
, &zb
);
224 zio_cksum_t cksum
= bp
->blk_cksum
;
227 * Validate the checksummed log block.
229 * Sequence numbers should be... sequential. The checksum
230 * verifier for the next block should be bp's checksum plus 1.
232 * Also check the log chain linkage and size used.
234 cksum
.zc_word
[ZIL_ZC_SEQ
]++;
236 if (BP_GET_CHECKSUM(bp
) == ZIO_CHECKSUM_ZILOG2
) {
237 zil_chain_t
*zilc
= abuf
->b_data
;
238 char *lr
= (char *)(zilc
+ 1);
239 uint64_t len
= zilc
->zc_nused
- sizeof (zil_chain_t
);
241 if (bcmp(&cksum
, &zilc
->zc_next_blk
.blk_cksum
,
242 sizeof (cksum
)) || BP_IS_HOLE(&zilc
->zc_next_blk
)) {
243 error
= SET_ERROR(ECKSUM
);
245 ASSERT3U(len
, <=, SPA_OLD_MAXBLOCKSIZE
);
247 *end
= (char *)dst
+ len
;
248 *nbp
= zilc
->zc_next_blk
;
251 char *lr
= abuf
->b_data
;
252 uint64_t size
= BP_GET_LSIZE(bp
);
253 zil_chain_t
*zilc
= (zil_chain_t
*)(lr
+ size
) - 1;
255 if (bcmp(&cksum
, &zilc
->zc_next_blk
.blk_cksum
,
256 sizeof (cksum
)) || BP_IS_HOLE(&zilc
->zc_next_blk
) ||
257 (zilc
->zc_nused
> (size
- sizeof (*zilc
)))) {
258 error
= SET_ERROR(ECKSUM
);
260 ASSERT3U(zilc
->zc_nused
, <=,
261 SPA_OLD_MAXBLOCKSIZE
);
262 bcopy(lr
, dst
, zilc
->zc_nused
);
263 *end
= (char *)dst
+ zilc
->zc_nused
;
264 *nbp
= zilc
->zc_next_blk
;
268 arc_buf_destroy(abuf
, &abuf
);
275 * Read a TX_WRITE log data block.
278 zil_read_log_data(zilog_t
*zilog
, const lr_write_t
*lr
, void *wbuf
)
280 enum zio_flag zio_flags
= ZIO_FLAG_CANFAIL
;
281 const blkptr_t
*bp
= &lr
->lr_blkptr
;
282 arc_flags_t aflags
= ARC_FLAG_WAIT
;
283 arc_buf_t
*abuf
= NULL
;
287 if (BP_IS_HOLE(bp
)) {
289 bzero(wbuf
, MAX(BP_GET_LSIZE(bp
), lr
->lr_length
));
293 if (zilog
->zl_header
->zh_claim_txg
== 0)
294 zio_flags
|= ZIO_FLAG_SPECULATIVE
| ZIO_FLAG_SCRUB
;
296 SET_BOOKMARK(&zb
, dmu_objset_id(zilog
->zl_os
), lr
->lr_foid
,
297 ZB_ZIL_LEVEL
, lr
->lr_offset
/ BP_GET_LSIZE(bp
));
299 error
= arc_read(NULL
, zilog
->zl_spa
, bp
, arc_getbuf_func
, &abuf
,
300 ZIO_PRIORITY_SYNC_READ
, zio_flags
, &aflags
, &zb
);
304 bcopy(abuf
->b_data
, wbuf
, arc_buf_size(abuf
));
305 arc_buf_destroy(abuf
, &abuf
);
312 * Parse the intent log, and call parse_func for each valid record within.
315 zil_parse(zilog_t
*zilog
, zil_parse_blk_func_t
*parse_blk_func
,
316 zil_parse_lr_func_t
*parse_lr_func
, void *arg
, uint64_t txg
)
318 const zil_header_t
*zh
= zilog
->zl_header
;
319 boolean_t claimed
= !!zh
->zh_claim_txg
;
320 uint64_t claim_blk_seq
= claimed
? zh
->zh_claim_blk_seq
: UINT64_MAX
;
321 uint64_t claim_lr_seq
= claimed
? zh
->zh_claim_lr_seq
: UINT64_MAX
;
322 uint64_t max_blk_seq
= 0;
323 uint64_t max_lr_seq
= 0;
324 uint64_t blk_count
= 0;
325 uint64_t lr_count
= 0;
326 blkptr_t blk
, next_blk
;
331 * Old logs didn't record the maximum zh_claim_lr_seq.
333 if (!(zh
->zh_flags
& ZIL_CLAIM_LR_SEQ_VALID
))
334 claim_lr_seq
= UINT64_MAX
;
337 * Starting at the block pointed to by zh_log we read the log chain.
338 * For each block in the chain we strongly check that block to
339 * ensure its validity. We stop when an invalid block is found.
340 * For each block pointer in the chain we call parse_blk_func().
341 * For each record in each valid block we call parse_lr_func().
342 * If the log has been claimed, stop if we encounter a sequence
343 * number greater than the highest claimed sequence number.
345 lrbuf
= zio_buf_alloc(SPA_OLD_MAXBLOCKSIZE
);
346 zil_bp_tree_init(zilog
);
348 for (blk
= zh
->zh_log
; !BP_IS_HOLE(&blk
); blk
= next_blk
) {
349 uint64_t blk_seq
= blk
.blk_cksum
.zc_word
[ZIL_ZC_SEQ
];
353 if (blk_seq
> claim_blk_seq
)
355 if ((error
= parse_blk_func(zilog
, &blk
, arg
, txg
)) != 0)
357 ASSERT3U(max_blk_seq
, <, blk_seq
);
358 max_blk_seq
= blk_seq
;
361 if (max_lr_seq
== claim_lr_seq
&& max_blk_seq
== claim_blk_seq
)
364 error
= zil_read_log_block(zilog
, &blk
, &next_blk
, lrbuf
, &end
);
368 for (lrp
= lrbuf
; lrp
< end
; lrp
+= reclen
) {
369 lr_t
*lr
= (lr_t
*)lrp
;
370 reclen
= lr
->lrc_reclen
;
371 ASSERT3U(reclen
, >=, sizeof (lr_t
));
372 if (lr
->lrc_seq
> claim_lr_seq
)
374 if ((error
= parse_lr_func(zilog
, lr
, arg
, txg
)) != 0)
376 ASSERT3U(max_lr_seq
, <, lr
->lrc_seq
);
377 max_lr_seq
= lr
->lrc_seq
;
382 zilog
->zl_parse_error
= error
;
383 zilog
->zl_parse_blk_seq
= max_blk_seq
;
384 zilog
->zl_parse_lr_seq
= max_lr_seq
;
385 zilog
->zl_parse_blk_count
= blk_count
;
386 zilog
->zl_parse_lr_count
= lr_count
;
388 ASSERT(!claimed
|| !(zh
->zh_flags
& ZIL_CLAIM_LR_SEQ_VALID
) ||
389 (max_blk_seq
== claim_blk_seq
&& max_lr_seq
== claim_lr_seq
));
391 zil_bp_tree_fini(zilog
);
392 zio_buf_free(lrbuf
, SPA_OLD_MAXBLOCKSIZE
);
399 zil_clear_log_block(zilog_t
*zilog
, blkptr_t
*bp
, void *tx
, uint64_t first_txg
)
401 ASSERT(!BP_IS_HOLE(bp
));
404 * As we call this function from the context of a rewind to a
405 * checkpoint, each ZIL block whose txg is later than the txg
406 * that we rewind to is invalid. Thus, we return -1 so
407 * zil_parse() doesn't attempt to read it.
409 if (bp
->blk_birth
>= first_txg
)
412 if (zil_bp_tree_add(zilog
, bp
) != 0)
415 zio_free(zilog
->zl_spa
, first_txg
, bp
);
421 zil_noop_log_record(zilog_t
*zilog
, lr_t
*lrc
, void *tx
, uint64_t first_txg
)
427 zil_claim_log_block(zilog_t
*zilog
, blkptr_t
*bp
, void *tx
, uint64_t first_txg
)
430 * Claim log block if not already committed and not already claimed.
431 * If tx == NULL, just verify that the block is claimable.
433 if (BP_IS_HOLE(bp
) || bp
->blk_birth
< first_txg
||
434 zil_bp_tree_add(zilog
, bp
) != 0)
437 return (zio_wait(zio_claim(NULL
, zilog
->zl_spa
,
438 tx
== NULL
? 0 : first_txg
, bp
, spa_claim_notify
, NULL
,
439 ZIO_FLAG_CANFAIL
| ZIO_FLAG_SPECULATIVE
| ZIO_FLAG_SCRUB
)));
443 zil_claim_log_record(zilog_t
*zilog
, lr_t
*lrc
, void *tx
, uint64_t first_txg
)
445 lr_write_t
*lr
= (lr_write_t
*)lrc
;
448 if (lrc
->lrc_txtype
!= TX_WRITE
)
452 * If the block is not readable, don't claim it. This can happen
453 * in normal operation when a log block is written to disk before
454 * some of the dmu_sync() blocks it points to. In this case, the
455 * transaction cannot have been committed to anyone (we would have
456 * waited for all writes to be stable first), so it is semantically
457 * correct to declare this the end of the log.
459 if (lr
->lr_blkptr
.blk_birth
>= first_txg
&&
460 (error
= zil_read_log_data(zilog
, lr
, NULL
)) != 0)
462 return (zil_claim_log_block(zilog
, &lr
->lr_blkptr
, tx
, first_txg
));
467 zil_free_log_block(zilog_t
*zilog
, blkptr_t
*bp
, void *tx
, uint64_t claim_txg
)
469 zio_free(zilog
->zl_spa
, dmu_tx_get_txg(tx
), bp
);
475 zil_free_log_record(zilog_t
*zilog
, lr_t
*lrc
, void *tx
, uint64_t claim_txg
)
477 lr_write_t
*lr
= (lr_write_t
*)lrc
;
478 blkptr_t
*bp
= &lr
->lr_blkptr
;
481 * If we previously claimed it, we need to free it.
483 if (claim_txg
!= 0 && lrc
->lrc_txtype
== TX_WRITE
&&
484 bp
->blk_birth
>= claim_txg
&& zil_bp_tree_add(zilog
, bp
) == 0 &&
486 zio_free(zilog
->zl_spa
, dmu_tx_get_txg(tx
), bp
);
492 zil_lwb_vdev_compare(const void *x1
, const void *x2
)
494 const uint64_t v1
= ((zil_vdev_node_t
*)x1
)->zv_vdev
;
495 const uint64_t v2
= ((zil_vdev_node_t
*)x2
)->zv_vdev
;
506 zil_alloc_lwb(zilog_t
*zilog
, blkptr_t
*bp
, boolean_t slog
, uint64_t txg
)
510 lwb
= kmem_cache_alloc(zil_lwb_cache
, KM_SLEEP
);
511 lwb
->lwb_zilog
= zilog
;
513 lwb
->lwb_slog
= slog
;
514 lwb
->lwb_state
= LWB_STATE_CLOSED
;
515 lwb
->lwb_buf
= zio_buf_alloc(BP_GET_LSIZE(bp
));
516 lwb
->lwb_max_txg
= txg
;
517 lwb
->lwb_write_zio
= NULL
;
518 lwb
->lwb_root_zio
= NULL
;
520 lwb
->lwb_issued_timestamp
= 0;
521 if (BP_GET_CHECKSUM(bp
) == ZIO_CHECKSUM_ZILOG2
) {
522 lwb
->lwb_nused
= sizeof (zil_chain_t
);
523 lwb
->lwb_sz
= BP_GET_LSIZE(bp
);
526 lwb
->lwb_sz
= BP_GET_LSIZE(bp
) - sizeof (zil_chain_t
);
529 mutex_enter(&zilog
->zl_lock
);
530 list_insert_tail(&zilog
->zl_lwb_list
, lwb
);
531 mutex_exit(&zilog
->zl_lock
);
533 ASSERT(!MUTEX_HELD(&lwb
->lwb_vdev_lock
));
534 ASSERT(avl_is_empty(&lwb
->lwb_vdev_tree
));
535 VERIFY(list_is_empty(&lwb
->lwb_waiters
));
541 zil_free_lwb(zilog_t
*zilog
, lwb_t
*lwb
)
543 ASSERT(MUTEX_HELD(&zilog
->zl_lock
));
544 ASSERT(!MUTEX_HELD(&lwb
->lwb_vdev_lock
));
545 VERIFY(list_is_empty(&lwb
->lwb_waiters
));
546 ASSERT(avl_is_empty(&lwb
->lwb_vdev_tree
));
547 ASSERT3P(lwb
->lwb_write_zio
, ==, NULL
);
548 ASSERT3P(lwb
->lwb_root_zio
, ==, NULL
);
549 ASSERT3U(lwb
->lwb_max_txg
, <=, spa_syncing_txg(zilog
->zl_spa
));
550 ASSERT(lwb
->lwb_state
== LWB_STATE_CLOSED
||
551 lwb
->lwb_state
== LWB_STATE_DONE
);
554 * Clear the zilog's field to indicate this lwb is no longer
555 * valid, and prevent use-after-free errors.
557 if (zilog
->zl_last_lwb_opened
== lwb
)
558 zilog
->zl_last_lwb_opened
= NULL
;
560 kmem_cache_free(zil_lwb_cache
, lwb
);
564 * Called when we create in-memory log transactions so that we know
565 * to cleanup the itxs at the end of spa_sync().
568 zilog_dirty(zilog_t
*zilog
, uint64_t txg
)
570 dsl_pool_t
*dp
= zilog
->zl_dmu_pool
;
571 dsl_dataset_t
*ds
= dmu_objset_ds(zilog
->zl_os
);
573 ASSERT(spa_writeable(zilog
->zl_spa
));
575 if (ds
->ds_is_snapshot
)
576 panic("dirtying snapshot!");
578 if (txg_list_add(&dp
->dp_dirty_zilogs
, zilog
, txg
)) {
579 /* up the hold count until we can be written out */
580 dmu_buf_add_ref(ds
->ds_dbuf
, zilog
);
582 zilog
->zl_dirty_max_txg
= MAX(txg
, zilog
->zl_dirty_max_txg
);
587 * Determine if the zil is dirty in the specified txg. Callers wanting to
588 * ensure that the dirty state does not change must hold the itxg_lock for
589 * the specified txg. Holding the lock will ensure that the zil cannot be
590 * dirtied (zil_itx_assign) or cleaned (zil_clean) while we check its current
594 zilog_is_dirty_in_txg(zilog_t
*zilog
, uint64_t txg
)
596 dsl_pool_t
*dp
= zilog
->zl_dmu_pool
;
598 if (txg_list_member(&dp
->dp_dirty_zilogs
, zilog
, txg
& TXG_MASK
))
604 * Determine if the zil is dirty. The zil is considered dirty if it has
605 * any pending itx records that have not been cleaned by zil_clean().
608 zilog_is_dirty(zilog_t
*zilog
)
610 dsl_pool_t
*dp
= zilog
->zl_dmu_pool
;
612 for (int t
= 0; t
< TXG_SIZE
; t
++) {
613 if (txg_list_member(&dp
->dp_dirty_zilogs
, zilog
, t
))
620 * Create an on-disk intent log.
623 zil_create(zilog_t
*zilog
)
625 const zil_header_t
*zh
= zilog
->zl_header
;
631 boolean_t slog
= FALSE
;
634 * Wait for any previous destroy to complete.
636 txg_wait_synced(zilog
->zl_dmu_pool
, zilog
->zl_destroy_txg
);
638 ASSERT(zh
->zh_claim_txg
== 0);
639 ASSERT(zh
->zh_replay_seq
== 0);
644 * Allocate an initial log block if:
645 * - there isn't one already
646 * - the existing block is the wrong endianess
648 if (BP_IS_HOLE(&blk
) || BP_SHOULD_BYTESWAP(&blk
)) {
649 tx
= dmu_tx_create(zilog
->zl_os
);
650 VERIFY0(dmu_tx_assign(tx
, TXG_WAIT
));
651 dsl_dataset_dirty(dmu_objset_ds(zilog
->zl_os
), tx
);
652 txg
= dmu_tx_get_txg(tx
);
654 if (!BP_IS_HOLE(&blk
)) {
655 zio_free(zilog
->zl_spa
, txg
, &blk
);
659 error
= zio_alloc_zil(zilog
->zl_spa
, txg
, &blk
, NULL
,
660 ZIL_MIN_BLKSZ
, &slog
);
663 zil_init_log_chain(zilog
, &blk
);
667 * Allocate a log write block (lwb) for the first log block.
670 lwb
= zil_alloc_lwb(zilog
, &blk
, slog
, txg
);
673 * If we just allocated the first log block, commit our transaction
674 * and wait for zil_sync() to stuff the block poiner into zh_log.
675 * (zh is part of the MOS, so we cannot modify it in open context.)
679 txg_wait_synced(zilog
->zl_dmu_pool
, txg
);
682 ASSERT(bcmp(&blk
, &zh
->zh_log
, sizeof (blk
)) == 0);
688 * In one tx, free all log blocks and clear the log header. If keep_first
689 * is set, then we're replaying a log with no content. We want to keep the
690 * first block, however, so that the first synchronous transaction doesn't
691 * require a txg_wait_synced() in zil_create(). We don't need to
692 * txg_wait_synced() here either when keep_first is set, because both
693 * zil_create() and zil_destroy() will wait for any in-progress destroys
697 zil_destroy(zilog_t
*zilog
, boolean_t keep_first
)
699 const zil_header_t
*zh
= zilog
->zl_header
;
705 * Wait for any previous destroy to complete.
707 txg_wait_synced(zilog
->zl_dmu_pool
, zilog
->zl_destroy_txg
);
709 zilog
->zl_old_header
= *zh
; /* debugging aid */
711 if (BP_IS_HOLE(&zh
->zh_log
))
714 tx
= dmu_tx_create(zilog
->zl_os
);
715 VERIFY0(dmu_tx_assign(tx
, TXG_WAIT
));
716 dsl_dataset_dirty(dmu_objset_ds(zilog
->zl_os
), tx
);
717 txg
= dmu_tx_get_txg(tx
);
719 mutex_enter(&zilog
->zl_lock
);
721 ASSERT3U(zilog
->zl_destroy_txg
, <, txg
);
722 zilog
->zl_destroy_txg
= txg
;
723 zilog
->zl_keep_first
= keep_first
;
725 if (!list_is_empty(&zilog
->zl_lwb_list
)) {
726 ASSERT(zh
->zh_claim_txg
== 0);
728 while ((lwb
= list_head(&zilog
->zl_lwb_list
)) != NULL
) {
729 list_remove(&zilog
->zl_lwb_list
, lwb
);
730 if (lwb
->lwb_buf
!= NULL
)
731 zio_buf_free(lwb
->lwb_buf
, lwb
->lwb_sz
);
732 zio_free(zilog
->zl_spa
, txg
, &lwb
->lwb_blk
);
733 zil_free_lwb(zilog
, lwb
);
735 } else if (!keep_first
) {
736 zil_destroy_sync(zilog
, tx
);
738 mutex_exit(&zilog
->zl_lock
);
744 zil_destroy_sync(zilog_t
*zilog
, dmu_tx_t
*tx
)
746 ASSERT(list_is_empty(&zilog
->zl_lwb_list
));
747 (void) zil_parse(zilog
, zil_free_log_block
,
748 zil_free_log_record
, tx
, zilog
->zl_header
->zh_claim_txg
);
752 zil_claim(dsl_pool_t
*dp
, dsl_dataset_t
*ds
, void *txarg
)
754 dmu_tx_t
*tx
= txarg
;
761 error
= dmu_objset_own_obj(dp
, ds
->ds_object
,
762 DMU_OST_ANY
, B_FALSE
, FTAG
, &os
);
765 * EBUSY indicates that the objset is inconsistent, in which
766 * case it can not have a ZIL.
768 if (error
!= EBUSY
) {
769 cmn_err(CE_WARN
, "can't open objset for %llu, error %u",
770 (unsigned long long)ds
->ds_object
, error
);
775 zilog
= dmu_objset_zil(os
);
776 zh
= zil_header_in_syncing_context(zilog
);
777 ASSERT3U(tx
->tx_txg
, ==, spa_first_txg(zilog
->zl_spa
));
778 first_txg
= spa_min_claim_txg(zilog
->zl_spa
);
781 * If the spa_log_state is not set to be cleared, check whether
782 * the current uberblock is a checkpoint one and if the current
783 * header has been claimed before moving on.
785 * If the current uberblock is a checkpointed uberblock then
786 * one of the following scenarios took place:
788 * 1] We are currently rewinding to the checkpoint of the pool.
789 * 2] We crashed in the middle of a checkpoint rewind but we
790 * did manage to write the checkpointed uberblock to the
791 * vdev labels, so when we tried to import the pool again
792 * the checkpointed uberblock was selected from the import
795 * In both cases we want to zero out all the ZIL blocks, except
796 * the ones that have been claimed at the time of the checkpoint
797 * (their zh_claim_txg != 0). The reason is that these blocks
798 * may be corrupted since we may have reused their locations on
799 * disk after we took the checkpoint.
801 * We could try to set spa_log_state to SPA_LOG_CLEAR earlier
802 * when we first figure out whether the current uberblock is
803 * checkpointed or not. Unfortunately, that would discard all
804 * the logs, including the ones that are claimed, and we would
807 if (spa_get_log_state(zilog
->zl_spa
) == SPA_LOG_CLEAR
||
808 (zilog
->zl_spa
->spa_uberblock
.ub_checkpoint_txg
!= 0 &&
809 zh
->zh_claim_txg
== 0)) {
810 if (!BP_IS_HOLE(&zh
->zh_log
)) {
811 (void) zil_parse(zilog
, zil_clear_log_block
,
812 zil_noop_log_record
, tx
, first_txg
);
814 BP_ZERO(&zh
->zh_log
);
815 dsl_dataset_dirty(dmu_objset_ds(os
), tx
);
816 dmu_objset_disown(os
, FTAG
);
821 * If we are not rewinding and opening the pool normally, then
822 * the min_claim_txg should be equal to the first txg of the pool.
824 ASSERT3U(first_txg
, ==, spa_first_txg(zilog
->zl_spa
));
827 * Claim all log blocks if we haven't already done so, and remember
828 * the highest claimed sequence number. This ensures that if we can
829 * read only part of the log now (e.g. due to a missing device),
830 * but we can read the entire log later, we will not try to replay
831 * or destroy beyond the last block we successfully claimed.
833 ASSERT3U(zh
->zh_claim_txg
, <=, first_txg
);
834 if (zh
->zh_claim_txg
== 0 && !BP_IS_HOLE(&zh
->zh_log
)) {
835 (void) zil_parse(zilog
, zil_claim_log_block
,
836 zil_claim_log_record
, tx
, first_txg
);
837 zh
->zh_claim_txg
= first_txg
;
838 zh
->zh_claim_blk_seq
= zilog
->zl_parse_blk_seq
;
839 zh
->zh_claim_lr_seq
= zilog
->zl_parse_lr_seq
;
840 if (zilog
->zl_parse_lr_count
|| zilog
->zl_parse_blk_count
> 1)
841 zh
->zh_flags
|= ZIL_REPLAY_NEEDED
;
842 zh
->zh_flags
|= ZIL_CLAIM_LR_SEQ_VALID
;
843 dsl_dataset_dirty(dmu_objset_ds(os
), tx
);
846 ASSERT3U(first_txg
, ==, (spa_last_synced_txg(zilog
->zl_spa
) + 1));
847 dmu_objset_disown(os
, FTAG
);
852 * Check the log by walking the log chain.
853 * Checksum errors are ok as they indicate the end of the chain.
854 * Any other error (no device or read failure) returns an error.
858 zil_check_log_chain(dsl_pool_t
*dp
, dsl_dataset_t
*ds
, void *tx
)
867 error
= dmu_objset_from_ds(ds
, &os
);
869 cmn_err(CE_WARN
, "can't open objset %llu, error %d",
870 (unsigned long long)ds
->ds_object
, error
);
874 zilog
= dmu_objset_zil(os
);
875 bp
= (blkptr_t
*)&zilog
->zl_header
->zh_log
;
877 if (!BP_IS_HOLE(bp
)) {
879 boolean_t valid
= B_TRUE
;
882 * Check the first block and determine if it's on a log device
883 * which may have been removed or faulted prior to loading this
884 * pool. If so, there's no point in checking the rest of the
885 * log as its content should have already been synced to the
888 spa_config_enter(os
->os_spa
, SCL_STATE
, FTAG
, RW_READER
);
889 vd
= vdev_lookup_top(os
->os_spa
, DVA_GET_VDEV(&bp
->blk_dva
[0]));
890 if (vd
->vdev_islog
&& vdev_is_dead(vd
))
891 valid
= vdev_log_state_valid(vd
);
892 spa_config_exit(os
->os_spa
, SCL_STATE
, FTAG
);
898 * Check whether the current uberblock is checkpointed (e.g.
899 * we are rewinding) and whether the current header has been
900 * claimed or not. If it hasn't then skip verifying it. We
901 * do this because its ZIL blocks may be part of the pool's
902 * state before the rewind, which is no longer valid.
904 zil_header_t
*zh
= zil_header_in_syncing_context(zilog
);
905 if (zilog
->zl_spa
->spa_uberblock
.ub_checkpoint_txg
!= 0 &&
906 zh
->zh_claim_txg
== 0)
911 * Because tx == NULL, zil_claim_log_block() will not actually claim
912 * any blocks, but just determine whether it is possible to do so.
913 * In addition to checking the log chain, zil_claim_log_block()
914 * will invoke zio_claim() with a done func of spa_claim_notify(),
915 * which will update spa_max_claim_txg. See spa_load() for details.
917 error
= zil_parse(zilog
, zil_claim_log_block
, zil_claim_log_record
, tx
,
918 zilog
->zl_header
->zh_claim_txg
? -1ULL :
919 spa_min_claim_txg(os
->os_spa
));
921 return ((error
== ECKSUM
|| error
== ENOENT
) ? 0 : error
);
925 * When an itx is "skipped", this function is used to properly mark the
926 * waiter as "done, and signal any thread(s) waiting on it. An itx can
927 * be skipped (and not committed to an lwb) for a variety of reasons,
928 * one of them being that the itx was committed via spa_sync(), prior to
929 * it being committed to an lwb; this can happen if a thread calling
930 * zil_commit() is racing with spa_sync().
933 zil_commit_waiter_skip(zil_commit_waiter_t
*zcw
)
935 mutex_enter(&zcw
->zcw_lock
);
936 ASSERT3B(zcw
->zcw_done
, ==, B_FALSE
);
937 zcw
->zcw_done
= B_TRUE
;
938 cv_broadcast(&zcw
->zcw_cv
);
939 mutex_exit(&zcw
->zcw_lock
);
943 * This function is used when the given waiter is to be linked into an
944 * lwb's "lwb_waiter" list; i.e. when the itx is committed to the lwb.
945 * At this point, the waiter will no longer be referenced by the itx,
946 * and instead, will be referenced by the lwb.
949 zil_commit_waiter_link_lwb(zil_commit_waiter_t
*zcw
, lwb_t
*lwb
)
952 * The lwb_waiters field of the lwb is protected by the zilog's
953 * zl_lock, thus it must be held when calling this function.
955 ASSERT(MUTEX_HELD(&lwb
->lwb_zilog
->zl_lock
));
957 mutex_enter(&zcw
->zcw_lock
);
958 ASSERT(!list_link_active(&zcw
->zcw_node
));
959 ASSERT3P(zcw
->zcw_lwb
, ==, NULL
);
960 ASSERT3P(lwb
, !=, NULL
);
961 ASSERT(lwb
->lwb_state
== LWB_STATE_OPENED
||
962 lwb
->lwb_state
== LWB_STATE_ISSUED
);
964 list_insert_tail(&lwb
->lwb_waiters
, zcw
);
966 mutex_exit(&zcw
->zcw_lock
);
970 * This function is used when zio_alloc_zil() fails to allocate a ZIL
971 * block, and the given waiter must be linked to the "nolwb waiters"
972 * list inside of zil_process_commit_list().
975 zil_commit_waiter_link_nolwb(zil_commit_waiter_t
*zcw
, list_t
*nolwb
)
977 mutex_enter(&zcw
->zcw_lock
);
978 ASSERT(!list_link_active(&zcw
->zcw_node
));
979 ASSERT3P(zcw
->zcw_lwb
, ==, NULL
);
980 list_insert_tail(nolwb
, zcw
);
981 mutex_exit(&zcw
->zcw_lock
);
985 zil_lwb_add_block(lwb_t
*lwb
, const blkptr_t
*bp
)
987 avl_tree_t
*t
= &lwb
->lwb_vdev_tree
;
989 zil_vdev_node_t
*zv
, zvsearch
;
990 int ndvas
= BP_GET_NDVAS(bp
);
993 if (zfs_nocacheflush
)
996 mutex_enter(&lwb
->lwb_vdev_lock
);
997 for (i
= 0; i
< ndvas
; i
++) {
998 zvsearch
.zv_vdev
= DVA_GET_VDEV(&bp
->blk_dva
[i
]);
999 if (avl_find(t
, &zvsearch
, &where
) == NULL
) {
1000 zv
= kmem_alloc(sizeof (*zv
), KM_SLEEP
);
1001 zv
->zv_vdev
= zvsearch
.zv_vdev
;
1002 avl_insert(t
, zv
, where
);
1005 mutex_exit(&lwb
->lwb_vdev_lock
);
1009 zil_lwb_add_txg(lwb_t
*lwb
, uint64_t txg
)
1011 lwb
->lwb_max_txg
= MAX(lwb
->lwb_max_txg
, txg
);
1015 * This function is a called after all VDEVs associated with a given lwb
1016 * write have completed their DKIOCFLUSHWRITECACHE command; or as soon
1017 * as the lwb write completes, if "zfs_nocacheflush" is set.
1019 * The intention is for this function to be called as soon as the
1020 * contents of an lwb are considered "stable" on disk, and will survive
1021 * any sudden loss of power. At this point, any threads waiting for the
1022 * lwb to reach this state are signalled, and the "waiter" structures
1023 * are marked "done".
1026 zil_lwb_flush_vdevs_done(zio_t
*zio
)
1028 lwb_t
*lwb
= zio
->io_private
;
1029 zilog_t
*zilog
= lwb
->lwb_zilog
;
1030 dmu_tx_t
*tx
= lwb
->lwb_tx
;
1031 zil_commit_waiter_t
*zcw
;
1033 spa_config_exit(zilog
->zl_spa
, SCL_STATE
, lwb
);
1035 zio_buf_free(lwb
->lwb_buf
, lwb
->lwb_sz
);
1037 mutex_enter(&zilog
->zl_lock
);
1040 * Ensure the lwb buffer pointer is cleared before releasing the
1041 * txg. If we have had an allocation failure and the txg is
1042 * waiting to sync then we want zil_sync() to remove the lwb so
1043 * that it's not picked up as the next new one in
1044 * zil_process_commit_list(). zil_sync() will only remove the
1045 * lwb if lwb_buf is null.
1047 lwb
->lwb_buf
= NULL
;
1050 ASSERT3U(lwb
->lwb_issued_timestamp
, >, 0);
1051 zilog
->zl_last_lwb_latency
= gethrtime() - lwb
->lwb_issued_timestamp
;
1053 lwb
->lwb_root_zio
= NULL
;
1054 lwb
->lwb_state
= LWB_STATE_DONE
;
1056 if (zilog
->zl_last_lwb_opened
== lwb
) {
1058 * Remember the highest committed log sequence number
1059 * for ztest. We only update this value when all the log
1060 * writes succeeded, because ztest wants to ASSERT that
1061 * it got the whole log chain.
1063 zilog
->zl_commit_lr_seq
= zilog
->zl_lr_seq
;
1066 while ((zcw
= list_head(&lwb
->lwb_waiters
)) != NULL
) {
1067 mutex_enter(&zcw
->zcw_lock
);
1069 ASSERT(list_link_active(&zcw
->zcw_node
));
1070 list_remove(&lwb
->lwb_waiters
, zcw
);
1072 ASSERT3P(zcw
->zcw_lwb
, ==, lwb
);
1073 zcw
->zcw_lwb
= NULL
;
1075 zcw
->zcw_zio_error
= zio
->io_error
;
1077 ASSERT3B(zcw
->zcw_done
, ==, B_FALSE
);
1078 zcw
->zcw_done
= B_TRUE
;
1079 cv_broadcast(&zcw
->zcw_cv
);
1081 mutex_exit(&zcw
->zcw_lock
);
1084 mutex_exit(&zilog
->zl_lock
);
1087 * Now that we've written this log block, we have a stable pointer
1088 * to the next block in the chain, so it's OK to let the txg in
1089 * which we allocated the next block sync.
1095 * This is called when an lwb write completes. This means, this specific
1096 * lwb was written to disk, and all dependent lwb have also been
1099 * At this point, a DKIOCFLUSHWRITECACHE command hasn't been issued to
1100 * the VDEVs involved in writing out this specific lwb. The lwb will be
1101 * "done" once zil_lwb_flush_vdevs_done() is called, which occurs in the
1102 * zio completion callback for the lwb's root zio.
1105 zil_lwb_write_done(zio_t
*zio
)
1107 lwb_t
*lwb
= zio
->io_private
;
1108 spa_t
*spa
= zio
->io_spa
;
1109 zilog_t
*zilog
= lwb
->lwb_zilog
;
1110 avl_tree_t
*t
= &lwb
->lwb_vdev_tree
;
1111 void *cookie
= NULL
;
1112 zil_vdev_node_t
*zv
;
1114 ASSERT3S(spa_config_held(spa
, SCL_STATE
, RW_READER
), !=, 0);
1116 ASSERT(BP_GET_COMPRESS(zio
->io_bp
) == ZIO_COMPRESS_OFF
);
1117 ASSERT(BP_GET_TYPE(zio
->io_bp
) == DMU_OT_INTENT_LOG
);
1118 ASSERT(BP_GET_LEVEL(zio
->io_bp
) == 0);
1119 ASSERT(BP_GET_BYTEORDER(zio
->io_bp
) == ZFS_HOST_BYTEORDER
);
1120 ASSERT(!BP_IS_GANG(zio
->io_bp
));
1121 ASSERT(!BP_IS_HOLE(zio
->io_bp
));
1122 ASSERT(BP_GET_FILL(zio
->io_bp
) == 0);
1124 abd_put(zio
->io_abd
);
1126 ASSERT3S(lwb
->lwb_state
, ==, LWB_STATE_ISSUED
);
1128 mutex_enter(&zilog
->zl_lock
);
1129 lwb
->lwb_write_zio
= NULL
;
1130 mutex_exit(&zilog
->zl_lock
);
1132 if (avl_numnodes(t
) == 0)
1136 * If there was an IO error, we're not going to call zio_flush()
1137 * on these vdevs, so we simply empty the tree and free the
1138 * nodes. We avoid calling zio_flush() since there isn't any
1139 * good reason for doing so, after the lwb block failed to be
1142 if (zio
->io_error
!= 0) {
1143 while ((zv
= avl_destroy_nodes(t
, &cookie
)) != NULL
)
1144 kmem_free(zv
, sizeof (*zv
));
1148 while ((zv
= avl_destroy_nodes(t
, &cookie
)) != NULL
) {
1149 vdev_t
*vd
= vdev_lookup_top(spa
, zv
->zv_vdev
);
1151 zio_flush(lwb
->lwb_root_zio
, vd
);
1152 kmem_free(zv
, sizeof (*zv
));
1157 * This function's purpose is to "open" an lwb such that it is ready to
1158 * accept new itxs being committed to it. To do this, the lwb's zio
1159 * structures are created, and linked to the lwb. This function is
1160 * idempotent; if the passed in lwb has already been opened, this
1161 * function is essentially a no-op.
1164 zil_lwb_write_open(zilog_t
*zilog
, lwb_t
*lwb
)
1166 zbookmark_phys_t zb
;
1167 zio_priority_t prio
;
1169 ASSERT(MUTEX_HELD(&zilog
->zl_issuer_lock
));
1170 ASSERT3P(lwb
, !=, NULL
);
1171 EQUIV(lwb
->lwb_root_zio
== NULL
, lwb
->lwb_state
== LWB_STATE_CLOSED
);
1172 EQUIV(lwb
->lwb_root_zio
!= NULL
, lwb
->lwb_state
== LWB_STATE_OPENED
);
1174 SET_BOOKMARK(&zb
, lwb
->lwb_blk
.blk_cksum
.zc_word
[ZIL_ZC_OBJSET
],
1175 ZB_ZIL_OBJECT
, ZB_ZIL_LEVEL
,
1176 lwb
->lwb_blk
.blk_cksum
.zc_word
[ZIL_ZC_SEQ
]);
1178 if (lwb
->lwb_root_zio
== NULL
) {
1179 abd_t
*lwb_abd
= abd_get_from_buf(lwb
->lwb_buf
,
1180 BP_GET_LSIZE(&lwb
->lwb_blk
));
1182 if (!lwb
->lwb_slog
|| zilog
->zl_cur_used
<= zil_slog_bulk
)
1183 prio
= ZIO_PRIORITY_SYNC_WRITE
;
1185 prio
= ZIO_PRIORITY_ASYNC_WRITE
;
1187 lwb
->lwb_root_zio
= zio_root(zilog
->zl_spa
,
1188 zil_lwb_flush_vdevs_done
, lwb
, ZIO_FLAG_CANFAIL
);
1189 ASSERT3P(lwb
->lwb_root_zio
, !=, NULL
);
1191 lwb
->lwb_write_zio
= zio_rewrite(lwb
->lwb_root_zio
,
1192 zilog
->zl_spa
, 0, &lwb
->lwb_blk
, lwb_abd
,
1193 BP_GET_LSIZE(&lwb
->lwb_blk
), zil_lwb_write_done
, lwb
,
1194 prio
, ZIO_FLAG_CANFAIL
| ZIO_FLAG_DONT_PROPAGATE
, &zb
);
1195 ASSERT3P(lwb
->lwb_write_zio
, !=, NULL
);
1197 lwb
->lwb_state
= LWB_STATE_OPENED
;
1199 mutex_enter(&zilog
->zl_lock
);
1202 * The zilog's "zl_last_lwb_opened" field is used to
1203 * build the lwb/zio dependency chain, which is used to
1204 * preserve the ordering of lwb completions that is
1205 * required by the semantics of the ZIL. Each new lwb
1206 * zio becomes a parent of the "previous" lwb zio, such
1207 * that the new lwb's zio cannot complete until the
1208 * "previous" lwb's zio completes.
1210 * This is required by the semantics of zil_commit();
1211 * the commit waiters attached to the lwbs will be woken
1212 * in the lwb zio's completion callback, so this zio
1213 * dependency graph ensures the waiters are woken in the
1214 * correct order (the same order the lwbs were created).
1216 lwb_t
*last_lwb_opened
= zilog
->zl_last_lwb_opened
;
1217 if (last_lwb_opened
!= NULL
&&
1218 last_lwb_opened
->lwb_state
!= LWB_STATE_DONE
) {
1219 ASSERT(last_lwb_opened
->lwb_state
== LWB_STATE_OPENED
||
1220 last_lwb_opened
->lwb_state
== LWB_STATE_ISSUED
);
1221 ASSERT3P(last_lwb_opened
->lwb_root_zio
, !=, NULL
);
1222 zio_add_child(lwb
->lwb_root_zio
,
1223 last_lwb_opened
->lwb_root_zio
);
1225 zilog
->zl_last_lwb_opened
= lwb
;
1227 mutex_exit(&zilog
->zl_lock
);
1230 ASSERT3P(lwb
->lwb_root_zio
, !=, NULL
);
1231 ASSERT3P(lwb
->lwb_write_zio
, !=, NULL
);
1232 ASSERT3S(lwb
->lwb_state
, ==, LWB_STATE_OPENED
);
1236 * Define a limited set of intent log block sizes.
1238 * These must be a multiple of 4KB. Note only the amount used (again
1239 * aligned to 4KB) actually gets written. However, we can't always just
1240 * allocate SPA_OLD_MAXBLOCKSIZE as the slog space could be exhausted.
1242 uint64_t zil_block_buckets
[] = {
1243 4096, /* non TX_WRITE */
1244 8192+4096, /* data base */
1245 32*1024 + 4096, /* NFS writes */
1250 * Start a log block write and advance to the next log block.
1251 * Calls are serialized.
1254 zil_lwb_write_issue(zilog_t
*zilog
, lwb_t
*lwb
)
1258 spa_t
*spa
= zilog
->zl_spa
;
1262 uint64_t zil_blksz
, wsz
;
1266 ASSERT(MUTEX_HELD(&zilog
->zl_issuer_lock
));
1267 ASSERT3P(lwb
->lwb_root_zio
, !=, NULL
);
1268 ASSERT3P(lwb
->lwb_write_zio
, !=, NULL
);
1269 ASSERT3S(lwb
->lwb_state
, ==, LWB_STATE_OPENED
);
1271 if (BP_GET_CHECKSUM(&lwb
->lwb_blk
) == ZIO_CHECKSUM_ZILOG2
) {
1272 zilc
= (zil_chain_t
*)lwb
->lwb_buf
;
1273 bp
= &zilc
->zc_next_blk
;
1275 zilc
= (zil_chain_t
*)(lwb
->lwb_buf
+ lwb
->lwb_sz
);
1276 bp
= &zilc
->zc_next_blk
;
1279 ASSERT(lwb
->lwb_nused
<= lwb
->lwb_sz
);
1282 * Allocate the next block and save its address in this block
1283 * before writing it in order to establish the log chain.
1284 * Note that if the allocation of nlwb synced before we wrote
1285 * the block that points at it (lwb), we'd leak it if we crashed.
1286 * Therefore, we don't do dmu_tx_commit() until zil_lwb_write_done().
1287 * We dirty the dataset to ensure that zil_sync() will be called
1288 * to clean up in the event of allocation failure or I/O failure.
1291 tx
= dmu_tx_create(zilog
->zl_os
);
1294 * Since we are not going to create any new dirty data, and we
1295 * can even help with clearing the existing dirty data, we
1296 * should not be subject to the dirty data based delays. We
1297 * use TXG_NOTHROTTLE to bypass the delay mechanism.
1299 VERIFY0(dmu_tx_assign(tx
, TXG_WAIT
| TXG_NOTHROTTLE
));
1301 dsl_dataset_dirty(dmu_objset_ds(zilog
->zl_os
), tx
);
1302 txg
= dmu_tx_get_txg(tx
);
1307 * Log blocks are pre-allocated. Here we select the size of the next
1308 * block, based on size used in the last block.
1309 * - first find the smallest bucket that will fit the block from a
1310 * limited set of block sizes. This is because it's faster to write
1311 * blocks allocated from the same metaslab as they are adjacent or
1313 * - next find the maximum from the new suggested size and an array of
1314 * previous sizes. This lessens a picket fence effect of wrongly
1315 * guesssing the size if we have a stream of say 2k, 64k, 2k, 64k
1318 * Note we only write what is used, but we can't just allocate
1319 * the maximum block size because we can exhaust the available
1322 zil_blksz
= zilog
->zl_cur_used
+ sizeof (zil_chain_t
);
1323 for (i
= 0; zil_blksz
> zil_block_buckets
[i
]; i
++)
1325 zil_blksz
= zil_block_buckets
[i
];
1326 if (zil_blksz
== UINT64_MAX
)
1327 zil_blksz
= SPA_OLD_MAXBLOCKSIZE
;
1328 zilog
->zl_prev_blks
[zilog
->zl_prev_rotor
] = zil_blksz
;
1329 for (i
= 0; i
< ZIL_PREV_BLKS
; i
++)
1330 zil_blksz
= MAX(zil_blksz
, zilog
->zl_prev_blks
[i
]);
1331 zilog
->zl_prev_rotor
= (zilog
->zl_prev_rotor
+ 1) & (ZIL_PREV_BLKS
- 1);
1335 /* pass the old blkptr in order to spread log blocks across devs */
1336 error
= zio_alloc_zil(spa
, txg
, bp
, &lwb
->lwb_blk
, zil_blksz
, &slog
);
1338 ASSERT3U(bp
->blk_birth
, ==, txg
);
1339 bp
->blk_cksum
= lwb
->lwb_blk
.blk_cksum
;
1340 bp
->blk_cksum
.zc_word
[ZIL_ZC_SEQ
]++;
1343 * Allocate a new log write block (lwb).
1345 nlwb
= zil_alloc_lwb(zilog
, bp
, slog
, txg
);
1348 if (BP_GET_CHECKSUM(&lwb
->lwb_blk
) == ZIO_CHECKSUM_ZILOG2
) {
1349 /* For Slim ZIL only write what is used. */
1350 wsz
= P2ROUNDUP_TYPED(lwb
->lwb_nused
, ZIL_MIN_BLKSZ
, uint64_t);
1351 ASSERT3U(wsz
, <=, lwb
->lwb_sz
);
1352 zio_shrink(lwb
->lwb_write_zio
, wsz
);
1359 zilc
->zc_nused
= lwb
->lwb_nused
;
1360 zilc
->zc_eck
.zec_cksum
= lwb
->lwb_blk
.blk_cksum
;
1363 * clear unused data for security
1365 bzero(lwb
->lwb_buf
+ lwb
->lwb_nused
, wsz
- lwb
->lwb_nused
);
1367 spa_config_enter(zilog
->zl_spa
, SCL_STATE
, lwb
, RW_READER
);
1369 zil_lwb_add_block(lwb
, &lwb
->lwb_blk
);
1370 lwb
->lwb_issued_timestamp
= gethrtime();
1371 lwb
->lwb_state
= LWB_STATE_ISSUED
;
1373 zio_nowait(lwb
->lwb_root_zio
);
1374 zio_nowait(lwb
->lwb_write_zio
);
1377 * If there was an allocation failure then nlwb will be null which
1378 * forces a txg_wait_synced().
1384 zil_lwb_commit(zilog_t
*zilog
, itx_t
*itx
, lwb_t
*lwb
)
1387 lr_write_t
*lrwb
, *lrw
;
1389 uint64_t dlen
, dnow
, lwb_sp
, reclen
, txg
;
1391 ASSERT(MUTEX_HELD(&zilog
->zl_issuer_lock
));
1392 ASSERT3P(lwb
, !=, NULL
);
1393 ASSERT3P(lwb
->lwb_buf
, !=, NULL
);
1395 zil_lwb_write_open(zilog
, lwb
);
1398 lrw
= (lr_write_t
*)lrc
;
1401 * A commit itx doesn't represent any on-disk state; instead
1402 * it's simply used as a place holder on the commit list, and
1403 * provides a mechanism for attaching a "commit waiter" onto the
1404 * correct lwb (such that the waiter can be signalled upon
1405 * completion of that lwb). Thus, we don't process this itx's
1406 * log record if it's a commit itx (these itx's don't have log
1407 * records), and instead link the itx's waiter onto the lwb's
1410 * For more details, see the comment above zil_commit().
1412 if (lrc
->lrc_txtype
== TX_COMMIT
) {
1413 mutex_enter(&zilog
->zl_lock
);
1414 zil_commit_waiter_link_lwb(itx
->itx_private
, lwb
);
1415 itx
->itx_private
= NULL
;
1416 mutex_exit(&zilog
->zl_lock
);
1420 if (lrc
->lrc_txtype
== TX_WRITE
&& itx
->itx_wr_state
== WR_NEED_COPY
) {
1421 dlen
= P2ROUNDUP_TYPED(
1422 lrw
->lr_length
, sizeof (uint64_t), uint64_t);
1426 reclen
= lrc
->lrc_reclen
;
1427 zilog
->zl_cur_used
+= (reclen
+ dlen
);
1430 ASSERT3U(zilog
->zl_cur_used
, <, UINT64_MAX
- (reclen
+ dlen
));
1434 * If this record won't fit in the current log block, start a new one.
1435 * For WR_NEED_COPY optimize layout for minimal number of chunks.
1437 lwb_sp
= lwb
->lwb_sz
- lwb
->lwb_nused
;
1438 if (reclen
> lwb_sp
|| (reclen
+ dlen
> lwb_sp
&&
1439 lwb_sp
< ZIL_MAX_WASTE_SPACE
&& (dlen
% ZIL_MAX_LOG_DATA
== 0 ||
1440 lwb_sp
< reclen
+ dlen
% ZIL_MAX_LOG_DATA
))) {
1441 lwb
= zil_lwb_write_issue(zilog
, lwb
);
1444 zil_lwb_write_open(zilog
, lwb
);
1445 ASSERT(LWB_EMPTY(lwb
));
1446 lwb_sp
= lwb
->lwb_sz
- lwb
->lwb_nused
;
1447 ASSERT3U(reclen
+ MIN(dlen
, sizeof (uint64_t)), <=, lwb_sp
);
1450 dnow
= MIN(dlen
, lwb_sp
- reclen
);
1451 lr_buf
= lwb
->lwb_buf
+ lwb
->lwb_nused
;
1452 bcopy(lrc
, lr_buf
, reclen
);
1453 lrcb
= (lr_t
*)lr_buf
; /* Like lrc, but inside lwb. */
1454 lrwb
= (lr_write_t
*)lrcb
; /* Like lrw, but inside lwb. */
1457 * If it's a write, fetch the data or get its blkptr as appropriate.
1459 if (lrc
->lrc_txtype
== TX_WRITE
) {
1460 if (txg
> spa_freeze_txg(zilog
->zl_spa
))
1461 txg_wait_synced(zilog
->zl_dmu_pool
, txg
);
1462 if (itx
->itx_wr_state
!= WR_COPIED
) {
1466 if (itx
->itx_wr_state
== WR_NEED_COPY
) {
1467 dbuf
= lr_buf
+ reclen
;
1468 lrcb
->lrc_reclen
+= dnow
;
1469 if (lrwb
->lr_length
> dnow
)
1470 lrwb
->lr_length
= dnow
;
1471 lrw
->lr_offset
+= dnow
;
1472 lrw
->lr_length
-= dnow
;
1474 ASSERT(itx
->itx_wr_state
== WR_INDIRECT
);
1479 * We pass in the "lwb_write_zio" rather than
1480 * "lwb_root_zio" so that the "lwb_write_zio"
1481 * becomes the parent of any zio's created by
1482 * the "zl_get_data" callback. The vdevs are
1483 * flushed after the "lwb_write_zio" completes,
1484 * so we want to make sure that completion
1485 * callback waits for these additional zio's,
1486 * such that the vdevs used by those zio's will
1487 * be included in the lwb's vdev tree, and those
1488 * vdevs will be properly flushed. If we passed
1489 * in "lwb_root_zio" here, then these additional
1490 * vdevs may not be flushed; e.g. if these zio's
1491 * completed after "lwb_write_zio" completed.
1493 error
= zilog
->zl_get_data(itx
->itx_private
,
1494 lrwb
, dbuf
, lwb
, lwb
->lwb_write_zio
);
1497 txg_wait_synced(zilog
->zl_dmu_pool
, txg
);
1501 ASSERT(error
== ENOENT
|| error
== EEXIST
||
1509 * We're actually making an entry, so update lrc_seq to be the
1510 * log record sequence number. Note that this is generally not
1511 * equal to the itx sequence number because not all transactions
1512 * are synchronous, and sometimes spa_sync() gets there first.
1514 lrcb
->lrc_seq
= ++zilog
->zl_lr_seq
;
1515 lwb
->lwb_nused
+= reclen
+ dnow
;
1517 zil_lwb_add_txg(lwb
, txg
);
1519 ASSERT3U(lwb
->lwb_nused
, <=, lwb
->lwb_sz
);
1520 ASSERT0(P2PHASE(lwb
->lwb_nused
, sizeof (uint64_t)));
1524 zilog
->zl_cur_used
+= reclen
;
1532 zil_itx_create(uint64_t txtype
, size_t lrsize
)
1536 lrsize
= P2ROUNDUP_TYPED(lrsize
, sizeof (uint64_t), size_t);
1538 itx
= kmem_alloc(offsetof(itx_t
, itx_lr
) + lrsize
, KM_SLEEP
);
1539 itx
->itx_lr
.lrc_txtype
= txtype
;
1540 itx
->itx_lr
.lrc_reclen
= lrsize
;
1541 itx
->itx_lr
.lrc_seq
= 0; /* defensive */
1542 itx
->itx_sync
= B_TRUE
; /* default is synchronous */
1548 zil_itx_destroy(itx_t
*itx
)
1550 kmem_free(itx
, offsetof(itx_t
, itx_lr
) + itx
->itx_lr
.lrc_reclen
);
1554 * Free up the sync and async itxs. The itxs_t has already been detached
1555 * so no locks are needed.
1558 zil_itxg_clean(itxs_t
*itxs
)
1564 itx_async_node_t
*ian
;
1566 list
= &itxs
->i_sync_list
;
1567 while ((itx
= list_head(list
)) != NULL
) {
1569 * In the general case, commit itxs will not be found
1570 * here, as they'll be committed to an lwb via
1571 * zil_lwb_commit(), and free'd in that function. Having
1572 * said that, it is still possible for commit itxs to be
1573 * found here, due to the following race:
1575 * - a thread calls zil_commit() which assigns the
1576 * commit itx to a per-txg i_sync_list
1577 * - zil_itxg_clean() is called (e.g. via spa_sync())
1578 * while the waiter is still on the i_sync_list
1580 * There's nothing to prevent syncing the txg while the
1581 * waiter is on the i_sync_list. This normally doesn't
1582 * happen because spa_sync() is slower than zil_commit(),
1583 * but if zil_commit() calls txg_wait_synced() (e.g.
1584 * because zil_create() or zil_commit_writer_stall() is
1585 * called) we will hit this case.
1587 if (itx
->itx_lr
.lrc_txtype
== TX_COMMIT
)
1588 zil_commit_waiter_skip(itx
->itx_private
);
1590 list_remove(list
, itx
);
1591 zil_itx_destroy(itx
);
1595 t
= &itxs
->i_async_tree
;
1596 while ((ian
= avl_destroy_nodes(t
, &cookie
)) != NULL
) {
1597 list
= &ian
->ia_list
;
1598 while ((itx
= list_head(list
)) != NULL
) {
1599 list_remove(list
, itx
);
1600 /* commit itxs should never be on the async lists. */
1601 ASSERT3U(itx
->itx_lr
.lrc_txtype
, !=, TX_COMMIT
);
1602 zil_itx_destroy(itx
);
1605 kmem_free(ian
, sizeof (itx_async_node_t
));
1609 kmem_free(itxs
, sizeof (itxs_t
));
1613 zil_aitx_compare(const void *x1
, const void *x2
)
1615 const uint64_t o1
= ((itx_async_node_t
*)x1
)->ia_foid
;
1616 const uint64_t o2
= ((itx_async_node_t
*)x2
)->ia_foid
;
1627 * Remove all async itx with the given oid.
1630 zil_remove_async(zilog_t
*zilog
, uint64_t oid
)
1633 itx_async_node_t
*ian
;
1640 list_create(&clean_list
, sizeof (itx_t
), offsetof(itx_t
, itx_node
));
1642 if (spa_freeze_txg(zilog
->zl_spa
) != UINT64_MAX
) /* ziltest support */
1645 otxg
= spa_last_synced_txg(zilog
->zl_spa
) + 1;
1647 for (txg
= otxg
; txg
< (otxg
+ TXG_CONCURRENT_STATES
); txg
++) {
1648 itxg_t
*itxg
= &zilog
->zl_itxg
[txg
& TXG_MASK
];
1650 mutex_enter(&itxg
->itxg_lock
);
1651 if (itxg
->itxg_txg
!= txg
) {
1652 mutex_exit(&itxg
->itxg_lock
);
1657 * Locate the object node and append its list.
1659 t
= &itxg
->itxg_itxs
->i_async_tree
;
1660 ian
= avl_find(t
, &oid
, &where
);
1662 list_move_tail(&clean_list
, &ian
->ia_list
);
1663 mutex_exit(&itxg
->itxg_lock
);
1665 while ((itx
= list_head(&clean_list
)) != NULL
) {
1666 list_remove(&clean_list
, itx
);
1667 /* commit itxs should never be on the async lists. */
1668 ASSERT3U(itx
->itx_lr
.lrc_txtype
, !=, TX_COMMIT
);
1669 zil_itx_destroy(itx
);
1671 list_destroy(&clean_list
);
1675 zil_itx_assign(zilog_t
*zilog
, itx_t
*itx
, dmu_tx_t
*tx
)
1679 itxs_t
*itxs
, *clean
= NULL
;
1682 * Object ids can be re-instantiated in the next txg so
1683 * remove any async transactions to avoid future leaks.
1684 * This can happen if a fsync occurs on the re-instantiated
1685 * object for a WR_INDIRECT or WR_NEED_COPY write, which gets
1686 * the new file data and flushes a write record for the old object.
1688 if ((itx
->itx_lr
.lrc_txtype
& ~TX_CI
) == TX_REMOVE
)
1689 zil_remove_async(zilog
, itx
->itx_oid
);
1692 * Ensure the data of a renamed file is committed before the rename.
1694 if ((itx
->itx_lr
.lrc_txtype
& ~TX_CI
) == TX_RENAME
)
1695 zil_async_to_sync(zilog
, itx
->itx_oid
);
1697 if (spa_freeze_txg(zilog
->zl_spa
) != UINT64_MAX
)
1700 txg
= dmu_tx_get_txg(tx
);
1702 itxg
= &zilog
->zl_itxg
[txg
& TXG_MASK
];
1703 mutex_enter(&itxg
->itxg_lock
);
1704 itxs
= itxg
->itxg_itxs
;
1705 if (itxg
->itxg_txg
!= txg
) {
1708 * The zil_clean callback hasn't got around to cleaning
1709 * this itxg. Save the itxs for release below.
1710 * This should be rare.
1712 zfs_dbgmsg("zil_itx_assign: missed itx cleanup for "
1713 "txg %llu", itxg
->itxg_txg
);
1714 clean
= itxg
->itxg_itxs
;
1716 itxg
->itxg_txg
= txg
;
1717 itxs
= itxg
->itxg_itxs
= kmem_zalloc(sizeof (itxs_t
), KM_SLEEP
);
1719 list_create(&itxs
->i_sync_list
, sizeof (itx_t
),
1720 offsetof(itx_t
, itx_node
));
1721 avl_create(&itxs
->i_async_tree
, zil_aitx_compare
,
1722 sizeof (itx_async_node_t
),
1723 offsetof(itx_async_node_t
, ia_node
));
1725 if (itx
->itx_sync
) {
1726 list_insert_tail(&itxs
->i_sync_list
, itx
);
1728 avl_tree_t
*t
= &itxs
->i_async_tree
;
1729 uint64_t foid
= ((lr_ooo_t
*)&itx
->itx_lr
)->lr_foid
;
1730 itx_async_node_t
*ian
;
1733 ian
= avl_find(t
, &foid
, &where
);
1735 ian
= kmem_alloc(sizeof (itx_async_node_t
), KM_SLEEP
);
1736 list_create(&ian
->ia_list
, sizeof (itx_t
),
1737 offsetof(itx_t
, itx_node
));
1738 ian
->ia_foid
= foid
;
1739 avl_insert(t
, ian
, where
);
1741 list_insert_tail(&ian
->ia_list
, itx
);
1744 itx
->itx_lr
.lrc_txg
= dmu_tx_get_txg(tx
);
1747 * We don't want to dirty the ZIL using ZILTEST_TXG, because
1748 * zil_clean() will never be called using ZILTEST_TXG. Thus, we
1749 * need to be careful to always dirty the ZIL using the "real"
1750 * TXG (not itxg_txg) even when the SPA is frozen.
1752 zilog_dirty(zilog
, dmu_tx_get_txg(tx
));
1753 mutex_exit(&itxg
->itxg_lock
);
1755 /* Release the old itxs now we've dropped the lock */
1757 zil_itxg_clean(clean
);
1761 * If there are any in-memory intent log transactions which have now been
1762 * synced then start up a taskq to free them. We should only do this after we
1763 * have written out the uberblocks (i.e. txg has been comitted) so that
1764 * don't inadvertently clean out in-memory log records that would be required
1768 zil_clean(zilog_t
*zilog
, uint64_t synced_txg
)
1770 itxg_t
*itxg
= &zilog
->zl_itxg
[synced_txg
& TXG_MASK
];
1773 ASSERT3U(synced_txg
, <, ZILTEST_TXG
);
1775 mutex_enter(&itxg
->itxg_lock
);
1776 if (itxg
->itxg_itxs
== NULL
|| itxg
->itxg_txg
== ZILTEST_TXG
) {
1777 mutex_exit(&itxg
->itxg_lock
);
1780 ASSERT3U(itxg
->itxg_txg
, <=, synced_txg
);
1781 ASSERT3U(itxg
->itxg_txg
, !=, 0);
1782 clean_me
= itxg
->itxg_itxs
;
1783 itxg
->itxg_itxs
= NULL
;
1785 mutex_exit(&itxg
->itxg_lock
);
1787 * Preferably start a task queue to free up the old itxs but
1788 * if taskq_dispatch can't allocate resources to do that then
1789 * free it in-line. This should be rare. Note, using TQ_SLEEP
1790 * created a bad performance problem.
1792 ASSERT3P(zilog
->zl_dmu_pool
, !=, NULL
);
1793 ASSERT3P(zilog
->zl_dmu_pool
->dp_zil_clean_taskq
, !=, NULL
);
1794 if (taskq_dispatch(zilog
->zl_dmu_pool
->dp_zil_clean_taskq
,
1795 (void (*)(void *))zil_itxg_clean
, clean_me
, TQ_NOSLEEP
) == 0)
1796 zil_itxg_clean(clean_me
);
1800 * This function will traverse the queue of itxs that need to be
1801 * committed, and move them onto the ZIL's zl_itx_commit_list.
1804 zil_get_commit_list(zilog_t
*zilog
)
1807 list_t
*commit_list
= &zilog
->zl_itx_commit_list
;
1809 ASSERT(MUTEX_HELD(&zilog
->zl_issuer_lock
));
1811 if (spa_freeze_txg(zilog
->zl_spa
) != UINT64_MAX
) /* ziltest support */
1814 otxg
= spa_last_synced_txg(zilog
->zl_spa
) + 1;
1817 * This is inherently racy, since there is nothing to prevent
1818 * the last synced txg from changing. That's okay since we'll
1819 * only commit things in the future.
1821 for (txg
= otxg
; txg
< (otxg
+ TXG_CONCURRENT_STATES
); txg
++) {
1822 itxg_t
*itxg
= &zilog
->zl_itxg
[txg
& TXG_MASK
];
1824 mutex_enter(&itxg
->itxg_lock
);
1825 if (itxg
->itxg_txg
!= txg
) {
1826 mutex_exit(&itxg
->itxg_lock
);
1831 * If we're adding itx records to the zl_itx_commit_list,
1832 * then the zil better be dirty in this "txg". We can assert
1833 * that here since we're holding the itxg_lock which will
1834 * prevent spa_sync from cleaning it. Once we add the itxs
1835 * to the zl_itx_commit_list we must commit it to disk even
1836 * if it's unnecessary (i.e. the txg was synced).
1838 ASSERT(zilog_is_dirty_in_txg(zilog
, txg
) ||
1839 spa_freeze_txg(zilog
->zl_spa
) != UINT64_MAX
);
1840 list_move_tail(commit_list
, &itxg
->itxg_itxs
->i_sync_list
);
1842 mutex_exit(&itxg
->itxg_lock
);
1847 * Move the async itxs for a specified object to commit into sync lists.
1850 zil_async_to_sync(zilog_t
*zilog
, uint64_t foid
)
1853 itx_async_node_t
*ian
;
1857 if (spa_freeze_txg(zilog
->zl_spa
) != UINT64_MAX
) /* ziltest support */
1860 otxg
= spa_last_synced_txg(zilog
->zl_spa
) + 1;
1863 * This is inherently racy, since there is nothing to prevent
1864 * the last synced txg from changing.
1866 for (txg
= otxg
; txg
< (otxg
+ TXG_CONCURRENT_STATES
); txg
++) {
1867 itxg_t
*itxg
= &zilog
->zl_itxg
[txg
& TXG_MASK
];
1869 mutex_enter(&itxg
->itxg_lock
);
1870 if (itxg
->itxg_txg
!= txg
) {
1871 mutex_exit(&itxg
->itxg_lock
);
1876 * If a foid is specified then find that node and append its
1877 * list. Otherwise walk the tree appending all the lists
1878 * to the sync list. We add to the end rather than the
1879 * beginning to ensure the create has happened.
1881 t
= &itxg
->itxg_itxs
->i_async_tree
;
1883 ian
= avl_find(t
, &foid
, &where
);
1885 list_move_tail(&itxg
->itxg_itxs
->i_sync_list
,
1889 void *cookie
= NULL
;
1891 while ((ian
= avl_destroy_nodes(t
, &cookie
)) != NULL
) {
1892 list_move_tail(&itxg
->itxg_itxs
->i_sync_list
,
1894 list_destroy(&ian
->ia_list
);
1895 kmem_free(ian
, sizeof (itx_async_node_t
));
1898 mutex_exit(&itxg
->itxg_lock
);
1903 * This function will prune commit itxs that are at the head of the
1904 * commit list (it won't prune past the first non-commit itx), and
1905 * either: a) attach them to the last lwb that's still pending
1906 * completion, or b) skip them altogether.
1908 * This is used as a performance optimization to prevent commit itxs
1909 * from generating new lwbs when it's unnecessary to do so.
1912 zil_prune_commit_list(zilog_t
*zilog
)
1916 ASSERT(MUTEX_HELD(&zilog
->zl_issuer_lock
));
1918 while (itx
= list_head(&zilog
->zl_itx_commit_list
)) {
1919 lr_t
*lrc
= &itx
->itx_lr
;
1920 if (lrc
->lrc_txtype
!= TX_COMMIT
)
1923 mutex_enter(&zilog
->zl_lock
);
1925 lwb_t
*last_lwb
= zilog
->zl_last_lwb_opened
;
1926 if (last_lwb
== NULL
|| last_lwb
->lwb_state
== LWB_STATE_DONE
) {
1928 * All of the itxs this waiter was waiting on
1929 * must have already completed (or there were
1930 * never any itx's for it to wait on), so it's
1931 * safe to skip this waiter and mark it done.
1933 zil_commit_waiter_skip(itx
->itx_private
);
1935 zil_commit_waiter_link_lwb(itx
->itx_private
, last_lwb
);
1936 itx
->itx_private
= NULL
;
1939 mutex_exit(&zilog
->zl_lock
);
1941 list_remove(&zilog
->zl_itx_commit_list
, itx
);
1942 zil_itx_destroy(itx
);
1945 IMPLY(itx
!= NULL
, itx
->itx_lr
.lrc_txtype
!= TX_COMMIT
);
1949 zil_commit_writer_stall(zilog_t
*zilog
)
1952 * When zio_alloc_zil() fails to allocate the next lwb block on
1953 * disk, we must call txg_wait_synced() to ensure all of the
1954 * lwbs in the zilog's zl_lwb_list are synced and then freed (in
1955 * zil_sync()), such that any subsequent ZIL writer (i.e. a call
1956 * to zil_process_commit_list()) will have to call zil_create(),
1957 * and start a new ZIL chain.
1959 * Since zil_alloc_zil() failed, the lwb that was previously
1960 * issued does not have a pointer to the "next" lwb on disk.
1961 * Thus, if another ZIL writer thread was to allocate the "next"
1962 * on-disk lwb, that block could be leaked in the event of a
1963 * crash (because the previous lwb on-disk would not point to
1966 * We must hold the zilog's zl_issuer_lock while we do this, to
1967 * ensure no new threads enter zil_process_commit_list() until
1968 * all lwb's in the zl_lwb_list have been synced and freed
1969 * (which is achieved via the txg_wait_synced() call).
1971 ASSERT(MUTEX_HELD(&zilog
->zl_issuer_lock
));
1972 txg_wait_synced(zilog
->zl_dmu_pool
, 0);
1973 ASSERT3P(list_tail(&zilog
->zl_lwb_list
), ==, NULL
);
1977 * This function will traverse the commit list, creating new lwbs as
1978 * needed, and committing the itxs from the commit list to these newly
1979 * created lwbs. Additionally, as a new lwb is created, the previous
1980 * lwb will be issued to the zio layer to be written to disk.
1983 zil_process_commit_list(zilog_t
*zilog
)
1985 spa_t
*spa
= zilog
->zl_spa
;
1986 list_t nolwb_waiters
;
1990 ASSERT(MUTEX_HELD(&zilog
->zl_issuer_lock
));
1993 * Return if there's nothing to commit before we dirty the fs by
1994 * calling zil_create().
1996 if (list_head(&zilog
->zl_itx_commit_list
) == NULL
)
1999 list_create(&nolwb_waiters
, sizeof (zil_commit_waiter_t
),
2000 offsetof(zil_commit_waiter_t
, zcw_node
));
2002 lwb
= list_tail(&zilog
->zl_lwb_list
);
2004 lwb
= zil_create(zilog
);
2006 ASSERT3S(lwb
->lwb_state
, !=, LWB_STATE_ISSUED
);
2007 ASSERT3S(lwb
->lwb_state
, !=, LWB_STATE_DONE
);
2010 while (itx
= list_head(&zilog
->zl_itx_commit_list
)) {
2011 lr_t
*lrc
= &itx
->itx_lr
;
2012 uint64_t txg
= lrc
->lrc_txg
;
2014 ASSERT3U(txg
, !=, 0);
2016 if (lrc
->lrc_txtype
== TX_COMMIT
) {
2017 DTRACE_PROBE2(zil__process__commit__itx
,
2018 zilog_t
*, zilog
, itx_t
*, itx
);
2020 DTRACE_PROBE2(zil__process__normal__itx
,
2021 zilog_t
*, zilog
, itx_t
*, itx
);
2024 boolean_t synced
= txg
<= spa_last_synced_txg(spa
);
2025 boolean_t frozen
= txg
> spa_freeze_txg(spa
);
2028 * If the txg of this itx has already been synced out, then
2029 * we don't need to commit this itx to an lwb. This is
2030 * because the data of this itx will have already been
2031 * written to the main pool. This is inherently racy, and
2032 * it's still ok to commit an itx whose txg has already
2033 * been synced; this will result in a write that's
2034 * unnecessary, but will do no harm.
2036 * With that said, we always want to commit TX_COMMIT itxs
2037 * to an lwb, regardless of whether or not that itx's txg
2038 * has been synced out. We do this to ensure any OPENED lwb
2039 * will always have at least one zil_commit_waiter_t linked
2042 * As a counter-example, if we skipped TX_COMMIT itx's
2043 * whose txg had already been synced, the following
2044 * situation could occur if we happened to be racing with
2047 * 1. we commit a non-TX_COMMIT itx to an lwb, where the
2048 * itx's txg is 10 and the last synced txg is 9.
2049 * 2. spa_sync finishes syncing out txg 10.
2050 * 3. we move to the next itx in the list, it's a TX_COMMIT
2051 * whose txg is 10, so we skip it rather than committing
2052 * it to the lwb used in (1).
2054 * If the itx that is skipped in (3) is the last TX_COMMIT
2055 * itx in the commit list, than it's possible for the lwb
2056 * used in (1) to remain in the OPENED state indefinitely.
2058 * To prevent the above scenario from occuring, ensuring
2059 * that once an lwb is OPENED it will transition to ISSUED
2060 * and eventually DONE, we always commit TX_COMMIT itx's to
2061 * an lwb here, even if that itx's txg has already been
2064 * Finally, if the pool is frozen, we _always_ commit the
2065 * itx. The point of freezing the pool is to prevent data
2066 * from being written to the main pool via spa_sync, and
2067 * instead rely solely on the ZIL to persistently store the
2068 * data; i.e. when the pool is frozen, the last synced txg
2069 * value can't be trusted.
2071 if (frozen
|| !synced
|| lrc
->lrc_txtype
== TX_COMMIT
) {
2073 lwb
= zil_lwb_commit(zilog
, itx
, lwb
);
2074 } else if (lrc
->lrc_txtype
== TX_COMMIT
) {
2075 ASSERT3P(lwb
, ==, NULL
);
2076 zil_commit_waiter_link_nolwb(
2077 itx
->itx_private
, &nolwb_waiters
);
2081 list_remove(&zilog
->zl_itx_commit_list
, itx
);
2082 zil_itx_destroy(itx
);
2087 * This indicates zio_alloc_zil() failed to allocate the
2088 * "next" lwb on-disk. When this happens, we must stall
2089 * the ZIL write pipeline; see the comment within
2090 * zil_commit_writer_stall() for more details.
2092 zil_commit_writer_stall(zilog
);
2095 * Additionally, we have to signal and mark the "nolwb"
2096 * waiters as "done" here, since without an lwb, we
2097 * can't do this via zil_lwb_flush_vdevs_done() like
2100 zil_commit_waiter_t
*zcw
;
2101 while (zcw
= list_head(&nolwb_waiters
)) {
2102 zil_commit_waiter_skip(zcw
);
2103 list_remove(&nolwb_waiters
, zcw
);
2106 ASSERT(list_is_empty(&nolwb_waiters
));
2107 ASSERT3P(lwb
, !=, NULL
);
2108 ASSERT3S(lwb
->lwb_state
, !=, LWB_STATE_ISSUED
);
2109 ASSERT3S(lwb
->lwb_state
, !=, LWB_STATE_DONE
);
2112 * At this point, the ZIL block pointed at by the "lwb"
2113 * variable is in one of the following states: "closed"
2116 * If its "closed", then no itxs have been committed to
2117 * it, so there's no point in issuing its zio (i.e.
2120 * If its "open" state, then it contains one or more
2121 * itxs that eventually need to be committed to stable
2122 * storage. In this case we intentionally do not issue
2123 * the lwb's zio to disk yet, and instead rely on one of
2124 * the following two mechanisms for issuing the zio:
2126 * 1. Ideally, there will be more ZIL activity occuring
2127 * on the system, such that this function will be
2128 * immediately called again (not necessarily by the same
2129 * thread) and this lwb's zio will be issued via
2130 * zil_lwb_commit(). This way, the lwb is guaranteed to
2131 * be "full" when it is issued to disk, and we'll make
2132 * use of the lwb's size the best we can.
2134 * 2. If there isn't sufficient ZIL activity occuring on
2135 * the system, such that this lwb's zio isn't issued via
2136 * zil_lwb_commit(), zil_commit_waiter() will issue the
2137 * lwb's zio. If this occurs, the lwb is not guaranteed
2138 * to be "full" by the time its zio is issued, and means
2139 * the size of the lwb was "too large" given the amount
2140 * of ZIL activity occuring on the system at that time.
2142 * We do this for a couple of reasons:
2144 * 1. To try and reduce the number of IOPs needed to
2145 * write the same number of itxs. If an lwb has space
2146 * available in it's buffer for more itxs, and more itxs
2147 * will be committed relatively soon (relative to the
2148 * latency of performing a write), then it's beneficial
2149 * to wait for these "next" itxs. This way, more itxs
2150 * can be committed to stable storage with fewer writes.
2152 * 2. To try and use the largest lwb block size that the
2153 * incoming rate of itxs can support. Again, this is to
2154 * try and pack as many itxs into as few lwbs as
2155 * possible, without significantly impacting the latency
2156 * of each individual itx.
2162 * This function is responsible for ensuring the passed in commit waiter
2163 * (and associated commit itx) is committed to an lwb. If the waiter is
2164 * not already committed to an lwb, all itxs in the zilog's queue of
2165 * itxs will be processed. The assumption is the passed in waiter's
2166 * commit itx will found in the queue just like the other non-commit
2167 * itxs, such that when the entire queue is processed, the waiter will
2168 * have been commited to an lwb.
2170 * The lwb associated with the passed in waiter is not guaranteed to
2171 * have been issued by the time this function completes. If the lwb is
2172 * not issued, we rely on future calls to zil_commit_writer() to issue
2173 * the lwb, or the timeout mechanism found in zil_commit_waiter().
2176 zil_commit_writer(zilog_t
*zilog
, zil_commit_waiter_t
*zcw
)
2178 ASSERT(!MUTEX_HELD(&zilog
->zl_lock
));
2179 ASSERT(spa_writeable(zilog
->zl_spa
));
2181 mutex_enter(&zilog
->zl_issuer_lock
);
2183 if (zcw
->zcw_lwb
!= NULL
|| zcw
->zcw_done
) {
2185 * It's possible that, while we were waiting to acquire
2186 * the "zl_issuer_lock", another thread committed this
2187 * waiter to an lwb. If that occurs, we bail out early,
2188 * without processing any of the zilog's queue of itxs.
2190 * On certain workloads and system configurations, the
2191 * "zl_issuer_lock" can become highly contended. In an
2192 * attempt to reduce this contention, we immediately drop
2193 * the lock if the waiter has already been processed.
2195 * We've measured this optimization to reduce CPU spent
2196 * contending on this lock by up to 5%, using a system
2197 * with 32 CPUs, low latency storage (~50 usec writes),
2198 * and 1024 threads performing sync writes.
2203 zil_get_commit_list(zilog
);
2204 zil_prune_commit_list(zilog
);
2205 zil_process_commit_list(zilog
);
2208 mutex_exit(&zilog
->zl_issuer_lock
);
2212 zil_commit_waiter_timeout(zilog_t
*zilog
, zil_commit_waiter_t
*zcw
)
2214 ASSERT(!MUTEX_HELD(&zilog
->zl_issuer_lock
));
2215 ASSERT(MUTEX_HELD(&zcw
->zcw_lock
));
2216 ASSERT3B(zcw
->zcw_done
, ==, B_FALSE
);
2218 lwb_t
*lwb
= zcw
->zcw_lwb
;
2219 ASSERT3P(lwb
, !=, NULL
);
2220 ASSERT3S(lwb
->lwb_state
, !=, LWB_STATE_CLOSED
);
2223 * If the lwb has already been issued by another thread, we can
2224 * immediately return since there's no work to be done (the
2225 * point of this function is to issue the lwb). Additionally, we
2226 * do this prior to acquiring the zl_issuer_lock, to avoid
2227 * acquiring it when it's not necessary to do so.
2229 if (lwb
->lwb_state
== LWB_STATE_ISSUED
||
2230 lwb
->lwb_state
== LWB_STATE_DONE
)
2234 * In order to call zil_lwb_write_issue() we must hold the
2235 * zilog's "zl_issuer_lock". We can't simply acquire that lock,
2236 * since we're already holding the commit waiter's "zcw_lock",
2237 * and those two locks are aquired in the opposite order
2240 mutex_exit(&zcw
->zcw_lock
);
2241 mutex_enter(&zilog
->zl_issuer_lock
);
2242 mutex_enter(&zcw
->zcw_lock
);
2245 * Since we just dropped and re-acquired the commit waiter's
2246 * lock, we have to re-check to see if the waiter was marked
2247 * "done" during that process. If the waiter was marked "done",
2248 * the "lwb" pointer is no longer valid (it can be free'd after
2249 * the waiter is marked "done"), so without this check we could
2250 * wind up with a use-after-free error below.
2255 ASSERT3P(lwb
, ==, zcw
->zcw_lwb
);
2258 * We've already checked this above, but since we hadn't acquired
2259 * the zilog's zl_issuer_lock, we have to perform this check a
2260 * second time while holding the lock.
2262 * We don't need to hold the zl_lock since the lwb cannot transition
2263 * from OPENED to ISSUED while we hold the zl_issuer_lock. The lwb
2264 * _can_ transition from ISSUED to DONE, but it's OK to race with
2265 * that transition since we treat the lwb the same, whether it's in
2266 * the ISSUED or DONE states.
2268 * The important thing, is we treat the lwb differently depending on
2269 * if it's ISSUED or OPENED, and block any other threads that might
2270 * attempt to issue this lwb. For that reason we hold the
2271 * zl_issuer_lock when checking the lwb_state; we must not call
2272 * zil_lwb_write_issue() if the lwb had already been issued.
2274 * See the comment above the lwb_state_t structure definition for
2275 * more details on the lwb states, and locking requirements.
2277 if (lwb
->lwb_state
== LWB_STATE_ISSUED
||
2278 lwb
->lwb_state
== LWB_STATE_DONE
)
2281 ASSERT3S(lwb
->lwb_state
, ==, LWB_STATE_OPENED
);
2284 * As described in the comments above zil_commit_waiter() and
2285 * zil_process_commit_list(), we need to issue this lwb's zio
2286 * since we've reached the commit waiter's timeout and it still
2287 * hasn't been issued.
2289 lwb_t
*nlwb
= zil_lwb_write_issue(zilog
, lwb
);
2291 ASSERT3S(lwb
->lwb_state
, !=, LWB_STATE_OPENED
);
2294 * Since the lwb's zio hadn't been issued by the time this thread
2295 * reached its timeout, we reset the zilog's "zl_cur_used" field
2296 * to influence the zil block size selection algorithm.
2298 * By having to issue the lwb's zio here, it means the size of the
2299 * lwb was too large, given the incoming throughput of itxs. By
2300 * setting "zl_cur_used" to zero, we communicate this fact to the
2301 * block size selection algorithm, so it can take this informaiton
2302 * into account, and potentially select a smaller size for the
2303 * next lwb block that is allocated.
2305 zilog
->zl_cur_used
= 0;
2309 * When zil_lwb_write_issue() returns NULL, this
2310 * indicates zio_alloc_zil() failed to allocate the
2311 * "next" lwb on-disk. When this occurs, the ZIL write
2312 * pipeline must be stalled; see the comment within the
2313 * zil_commit_writer_stall() function for more details.
2315 * We must drop the commit waiter's lock prior to
2316 * calling zil_commit_writer_stall() or else we can wind
2317 * up with the following deadlock:
2319 * - This thread is waiting for the txg to sync while
2320 * holding the waiter's lock; txg_wait_synced() is
2321 * used within txg_commit_writer_stall().
2323 * - The txg can't sync because it is waiting for this
2324 * lwb's zio callback to call dmu_tx_commit().
2326 * - The lwb's zio callback can't call dmu_tx_commit()
2327 * because it's blocked trying to acquire the waiter's
2328 * lock, which occurs prior to calling dmu_tx_commit()
2330 mutex_exit(&zcw
->zcw_lock
);
2331 zil_commit_writer_stall(zilog
);
2332 mutex_enter(&zcw
->zcw_lock
);
2336 mutex_exit(&zilog
->zl_issuer_lock
);
2337 ASSERT(MUTEX_HELD(&zcw
->zcw_lock
));
2341 * This function is responsible for performing the following two tasks:
2343 * 1. its primary responsibility is to block until the given "commit
2344 * waiter" is considered "done".
2346 * 2. its secondary responsibility is to issue the zio for the lwb that
2347 * the given "commit waiter" is waiting on, if this function has
2348 * waited "long enough" and the lwb is still in the "open" state.
2350 * Given a sufficient amount of itxs being generated and written using
2351 * the ZIL, the lwb's zio will be issued via the zil_lwb_commit()
2352 * function. If this does not occur, this secondary responsibility will
2353 * ensure the lwb is issued even if there is not other synchronous
2354 * activity on the system.
2356 * For more details, see zil_process_commit_list(); more specifically,
2357 * the comment at the bottom of that function.
2360 zil_commit_waiter(zilog_t
*zilog
, zil_commit_waiter_t
*zcw
)
2362 ASSERT(!MUTEX_HELD(&zilog
->zl_lock
));
2363 ASSERT(!MUTEX_HELD(&zilog
->zl_issuer_lock
));
2364 ASSERT(spa_writeable(zilog
->zl_spa
));
2366 mutex_enter(&zcw
->zcw_lock
);
2369 * The timeout is scaled based on the lwb latency to avoid
2370 * significantly impacting the latency of each individual itx.
2371 * For more details, see the comment at the bottom of the
2372 * zil_process_commit_list() function.
2374 int pct
= MAX(zfs_commit_timeout_pct
, 1);
2375 hrtime_t sleep
= (zilog
->zl_last_lwb_latency
* pct
) / 100;
2376 hrtime_t wakeup
= gethrtime() + sleep
;
2377 boolean_t timedout
= B_FALSE
;
2379 while (!zcw
->zcw_done
) {
2380 ASSERT(MUTEX_HELD(&zcw
->zcw_lock
));
2382 lwb_t
*lwb
= zcw
->zcw_lwb
;
2385 * Usually, the waiter will have a non-NULL lwb field here,
2386 * but it's possible for it to be NULL as a result of
2387 * zil_commit() racing with spa_sync().
2389 * When zil_clean() is called, it's possible for the itxg
2390 * list (which may be cleaned via a taskq) to contain
2391 * commit itxs. When this occurs, the commit waiters linked
2392 * off of these commit itxs will not be committed to an
2393 * lwb. Additionally, these commit waiters will not be
2394 * marked done until zil_commit_waiter_skip() is called via
2397 * Thus, it's possible for this commit waiter (i.e. the
2398 * "zcw" variable) to be found in this "in between" state;
2399 * where it's "zcw_lwb" field is NULL, and it hasn't yet
2400 * been skipped, so it's "zcw_done" field is still B_FALSE.
2402 IMPLY(lwb
!= NULL
, lwb
->lwb_state
!= LWB_STATE_CLOSED
);
2404 if (lwb
!= NULL
&& lwb
->lwb_state
== LWB_STATE_OPENED
) {
2405 ASSERT3B(timedout
, ==, B_FALSE
);
2408 * If the lwb hasn't been issued yet, then we
2409 * need to wait with a timeout, in case this
2410 * function needs to issue the lwb after the
2411 * timeout is reached; responsibility (2) from
2412 * the comment above this function.
2414 clock_t timeleft
= cv_timedwait_hires(&zcw
->zcw_cv
,
2415 &zcw
->zcw_lock
, wakeup
, USEC2NSEC(1),
2416 CALLOUT_FLAG_ABSOLUTE
);
2418 if (timeleft
>= 0 || zcw
->zcw_done
)
2422 zil_commit_waiter_timeout(zilog
, zcw
);
2424 if (!zcw
->zcw_done
) {
2426 * If the commit waiter has already been
2427 * marked "done", it's possible for the
2428 * waiter's lwb structure to have already
2429 * been freed. Thus, we can only reliably
2430 * make these assertions if the waiter
2433 ASSERT3P(lwb
, ==, zcw
->zcw_lwb
);
2434 ASSERT3S(lwb
->lwb_state
, !=, LWB_STATE_OPENED
);
2438 * If the lwb isn't open, then it must have already
2439 * been issued. In that case, there's no need to
2440 * use a timeout when waiting for the lwb to
2443 * Additionally, if the lwb is NULL, the waiter
2444 * will soon be signalled and marked done via
2445 * zil_clean() and zil_itxg_clean(), so no timeout
2450 lwb
->lwb_state
== LWB_STATE_ISSUED
||
2451 lwb
->lwb_state
== LWB_STATE_DONE
);
2452 cv_wait(&zcw
->zcw_cv
, &zcw
->zcw_lock
);
2456 mutex_exit(&zcw
->zcw_lock
);
2459 static zil_commit_waiter_t
*
2460 zil_alloc_commit_waiter()
2462 zil_commit_waiter_t
*zcw
= kmem_cache_alloc(zil_zcw_cache
, KM_SLEEP
);
2464 cv_init(&zcw
->zcw_cv
, NULL
, CV_DEFAULT
, NULL
);
2465 mutex_init(&zcw
->zcw_lock
, NULL
, MUTEX_DEFAULT
, NULL
);
2466 list_link_init(&zcw
->zcw_node
);
2467 zcw
->zcw_lwb
= NULL
;
2468 zcw
->zcw_done
= B_FALSE
;
2469 zcw
->zcw_zio_error
= 0;
2475 zil_free_commit_waiter(zil_commit_waiter_t
*zcw
)
2477 ASSERT(!list_link_active(&zcw
->zcw_node
));
2478 ASSERT3P(zcw
->zcw_lwb
, ==, NULL
);
2479 ASSERT3B(zcw
->zcw_done
, ==, B_TRUE
);
2480 mutex_destroy(&zcw
->zcw_lock
);
2481 cv_destroy(&zcw
->zcw_cv
);
2482 kmem_cache_free(zil_zcw_cache
, zcw
);
2486 * This function is used to create a TX_COMMIT itx and assign it. This
2487 * way, it will be linked into the ZIL's list of synchronous itxs, and
2488 * then later committed to an lwb (or skipped) when
2489 * zil_process_commit_list() is called.
2492 zil_commit_itx_assign(zilog_t
*zilog
, zil_commit_waiter_t
*zcw
)
2494 dmu_tx_t
*tx
= dmu_tx_create(zilog
->zl_os
);
2495 VERIFY0(dmu_tx_assign(tx
, TXG_WAIT
));
2497 itx_t
*itx
= zil_itx_create(TX_COMMIT
, sizeof (lr_t
));
2498 itx
->itx_sync
= B_TRUE
;
2499 itx
->itx_private
= zcw
;
2501 zil_itx_assign(zilog
, itx
, tx
);
2507 * Commit ZFS Intent Log transactions (itxs) to stable storage.
2509 * When writing ZIL transactions to the on-disk representation of the
2510 * ZIL, the itxs are committed to a Log Write Block (lwb). Multiple
2511 * itxs can be committed to a single lwb. Once a lwb is written and
2512 * committed to stable storage (i.e. the lwb is written, and vdevs have
2513 * been flushed), each itx that was committed to that lwb is also
2514 * considered to be committed to stable storage.
2516 * When an itx is committed to an lwb, the log record (lr_t) contained
2517 * by the itx is copied into the lwb's zio buffer, and once this buffer
2518 * is written to disk, it becomes an on-disk ZIL block.
2520 * As itxs are generated, they're inserted into the ZIL's queue of
2521 * uncommitted itxs. The semantics of zil_commit() are such that it will
2522 * block until all itxs that were in the queue when it was called, are
2523 * committed to stable storage.
2525 * If "foid" is zero, this means all "synchronous" and "asynchronous"
2526 * itxs, for all objects in the dataset, will be committed to stable
2527 * storage prior to zil_commit() returning. If "foid" is non-zero, all
2528 * "synchronous" itxs for all objects, but only "asynchronous" itxs
2529 * that correspond to the foid passed in, will be committed to stable
2530 * storage prior to zil_commit() returning.
2532 * Generally speaking, when zil_commit() is called, the consumer doesn't
2533 * actually care about _all_ of the uncommitted itxs. Instead, they're
2534 * simply trying to waiting for a specific itx to be committed to disk,
2535 * but the interface(s) for interacting with the ZIL don't allow such
2536 * fine-grained communication. A better interface would allow a consumer
2537 * to create and assign an itx, and then pass a reference to this itx to
2538 * zil_commit(); such that zil_commit() would return as soon as that
2539 * specific itx was committed to disk (instead of waiting for _all_
2540 * itxs to be committed).
2542 * When a thread calls zil_commit() a special "commit itx" will be
2543 * generated, along with a corresponding "waiter" for this commit itx.
2544 * zil_commit() will wait on this waiter's CV, such that when the waiter
2545 * is marked done, and signalled, zil_commit() will return.
2547 * This commit itx is inserted into the queue of uncommitted itxs. This
2548 * provides an easy mechanism for determining which itxs were in the
2549 * queue prior to zil_commit() having been called, and which itxs were
2550 * added after zil_commit() was called.
2552 * The commit it is special; it doesn't have any on-disk representation.
2553 * When a commit itx is "committed" to an lwb, the waiter associated
2554 * with it is linked onto the lwb's list of waiters. Then, when that lwb
2555 * completes, each waiter on the lwb's list is marked done and signalled
2556 * -- allowing the thread waiting on the waiter to return from zil_commit().
2558 * It's important to point out a few critical factors that allow us
2559 * to make use of the commit itxs, commit waiters, per-lwb lists of
2560 * commit waiters, and zio completion callbacks like we're doing:
2562 * 1. The list of waiters for each lwb is traversed, and each commit
2563 * waiter is marked "done" and signalled, in the zio completion
2564 * callback of the lwb's zio[*].
2566 * * Actually, the waiters are signalled in the zio completion
2567 * callback of the root zio for the DKIOCFLUSHWRITECACHE commands
2568 * that are sent to the vdevs upon completion of the lwb zio.
2570 * 2. When the itxs are inserted into the ZIL's queue of uncommitted
2571 * itxs, the order in which they are inserted is preserved[*]; as
2572 * itxs are added to the queue, they are added to the tail of
2573 * in-memory linked lists.
2575 * When committing the itxs to lwbs (to be written to disk), they
2576 * are committed in the same order in which the itxs were added to
2577 * the uncommitted queue's linked list(s); i.e. the linked list of
2578 * itxs to commit is traversed from head to tail, and each itx is
2579 * committed to an lwb in that order.
2583 * - the order of "sync" itxs is preserved w.r.t. other
2584 * "sync" itxs, regardless of the corresponding objects.
2585 * - the order of "async" itxs is preserved w.r.t. other
2586 * "async" itxs corresponding to the same object.
2587 * - the order of "async" itxs is *not* preserved w.r.t. other
2588 * "async" itxs corresponding to different objects.
2589 * - the order of "sync" itxs w.r.t. "async" itxs (or vice
2590 * versa) is *not* preserved, even for itxs that correspond
2591 * to the same object.
2593 * For more details, see: zil_itx_assign(), zil_async_to_sync(),
2594 * zil_get_commit_list(), and zil_process_commit_list().
2596 * 3. The lwbs represent a linked list of blocks on disk. Thus, any
2597 * lwb cannot be considered committed to stable storage, until its
2598 * "previous" lwb is also committed to stable storage. This fact,
2599 * coupled with the fact described above, means that itxs are
2600 * committed in (roughly) the order in which they were generated.
2601 * This is essential because itxs are dependent on prior itxs.
2602 * Thus, we *must not* deem an itx as being committed to stable
2603 * storage, until *all* prior itxs have also been committed to
2606 * To enforce this ordering of lwb zio's, while still leveraging as
2607 * much of the underlying storage performance as possible, we rely
2608 * on two fundamental concepts:
2610 * 1. The creation and issuance of lwb zio's is protected by
2611 * the zilog's "zl_issuer_lock", which ensures only a single
2612 * thread is creating and/or issuing lwb's at a time
2613 * 2. The "previous" lwb is a child of the "current" lwb
2614 * (leveraging the zio parent-child depenency graph)
2616 * By relying on this parent-child zio relationship, we can have
2617 * many lwb zio's concurrently issued to the underlying storage,
2618 * but the order in which they complete will be the same order in
2619 * which they were created.
2622 zil_commit(zilog_t
*zilog
, uint64_t foid
)
2625 * We should never attempt to call zil_commit on a snapshot for
2626 * a couple of reasons:
2628 * 1. A snapshot may never be modified, thus it cannot have any
2629 * in-flight itxs that would have modified the dataset.
2631 * 2. By design, when zil_commit() is called, a commit itx will
2632 * be assigned to this zilog; as a result, the zilog will be
2633 * dirtied. We must not dirty the zilog of a snapshot; there's
2634 * checks in the code that enforce this invariant, and will
2635 * cause a panic if it's not upheld.
2637 ASSERT3B(dmu_objset_is_snapshot(zilog
->zl_os
), ==, B_FALSE
);
2639 if (zilog
->zl_sync
== ZFS_SYNC_DISABLED
)
2642 if (!spa_writeable(zilog
->zl_spa
)) {
2644 * If the SPA is not writable, there should never be any
2645 * pending itxs waiting to be committed to disk. If that
2646 * weren't true, we'd skip writing those itxs out, and
2647 * would break the sematics of zil_commit(); thus, we're
2648 * verifying that truth before we return to the caller.
2650 ASSERT(list_is_empty(&zilog
->zl_lwb_list
));
2651 ASSERT3P(zilog
->zl_last_lwb_opened
, ==, NULL
);
2652 for (int i
= 0; i
< TXG_SIZE
; i
++)
2653 ASSERT3P(zilog
->zl_itxg
[i
].itxg_itxs
, ==, NULL
);
2658 * If the ZIL is suspended, we don't want to dirty it by calling
2659 * zil_commit_itx_assign() below, nor can we write out
2660 * lwbs like would be done in zil_commit_write(). Thus, we
2661 * simply rely on txg_wait_synced() to maintain the necessary
2662 * semantics, and avoid calling those functions altogether.
2664 if (zilog
->zl_suspend
> 0) {
2665 txg_wait_synced(zilog
->zl_dmu_pool
, 0);
2669 zil_commit_impl(zilog
, foid
);
2673 zil_commit_impl(zilog_t
*zilog
, uint64_t foid
)
2676 * Move the "async" itxs for the specified foid to the "sync"
2677 * queues, such that they will be later committed (or skipped)
2678 * to an lwb when zil_process_commit_list() is called.
2680 * Since these "async" itxs must be committed prior to this
2681 * call to zil_commit returning, we must perform this operation
2682 * before we call zil_commit_itx_assign().
2684 zil_async_to_sync(zilog
, foid
);
2687 * We allocate a new "waiter" structure which will initially be
2688 * linked to the commit itx using the itx's "itx_private" field.
2689 * Since the commit itx doesn't represent any on-disk state,
2690 * when it's committed to an lwb, rather than copying the its
2691 * lr_t into the lwb's buffer, the commit itx's "waiter" will be
2692 * added to the lwb's list of waiters. Then, when the lwb is
2693 * committed to stable storage, each waiter in the lwb's list of
2694 * waiters will be marked "done", and signalled.
2696 * We must create the waiter and assign the commit itx prior to
2697 * calling zil_commit_writer(), or else our specific commit itx
2698 * is not guaranteed to be committed to an lwb prior to calling
2699 * zil_commit_waiter().
2701 zil_commit_waiter_t
*zcw
= zil_alloc_commit_waiter();
2702 zil_commit_itx_assign(zilog
, zcw
);
2704 zil_commit_writer(zilog
, zcw
);
2705 zil_commit_waiter(zilog
, zcw
);
2707 if (zcw
->zcw_zio_error
!= 0) {
2709 * If there was an error writing out the ZIL blocks that
2710 * this thread is waiting on, then we fallback to
2711 * relying on spa_sync() to write out the data this
2712 * thread is waiting on. Obviously this has performance
2713 * implications, but the expectation is for this to be
2714 * an exceptional case, and shouldn't occur often.
2716 DTRACE_PROBE2(zil__commit__io__error
,
2717 zilog_t
*, zilog
, zil_commit_waiter_t
*, zcw
);
2718 txg_wait_synced(zilog
->zl_dmu_pool
, 0);
2721 zil_free_commit_waiter(zcw
);
2725 * Called in syncing context to free committed log blocks and update log header.
2728 zil_sync(zilog_t
*zilog
, dmu_tx_t
*tx
)
2730 zil_header_t
*zh
= zil_header_in_syncing_context(zilog
);
2731 uint64_t txg
= dmu_tx_get_txg(tx
);
2732 spa_t
*spa
= zilog
->zl_spa
;
2733 uint64_t *replayed_seq
= &zilog
->zl_replayed_seq
[txg
& TXG_MASK
];
2737 * We don't zero out zl_destroy_txg, so make sure we don't try
2738 * to destroy it twice.
2740 if (spa_sync_pass(spa
) != 1)
2743 mutex_enter(&zilog
->zl_lock
);
2745 ASSERT(zilog
->zl_stop_sync
== 0);
2747 if (*replayed_seq
!= 0) {
2748 ASSERT(zh
->zh_replay_seq
< *replayed_seq
);
2749 zh
->zh_replay_seq
= *replayed_seq
;
2753 if (zilog
->zl_destroy_txg
== txg
) {
2754 blkptr_t blk
= zh
->zh_log
;
2756 ASSERT(list_head(&zilog
->zl_lwb_list
) == NULL
);
2758 bzero(zh
, sizeof (zil_header_t
));
2759 bzero(zilog
->zl_replayed_seq
, sizeof (zilog
->zl_replayed_seq
));
2761 if (zilog
->zl_keep_first
) {
2763 * If this block was part of log chain that couldn't
2764 * be claimed because a device was missing during
2765 * zil_claim(), but that device later returns,
2766 * then this block could erroneously appear valid.
2767 * To guard against this, assign a new GUID to the new
2768 * log chain so it doesn't matter what blk points to.
2770 zil_init_log_chain(zilog
, &blk
);
2775 while ((lwb
= list_head(&zilog
->zl_lwb_list
)) != NULL
) {
2776 zh
->zh_log
= lwb
->lwb_blk
;
2777 if (lwb
->lwb_buf
!= NULL
|| lwb
->lwb_max_txg
> txg
)
2779 list_remove(&zilog
->zl_lwb_list
, lwb
);
2780 zio_free(spa
, txg
, &lwb
->lwb_blk
);
2781 zil_free_lwb(zilog
, lwb
);
2784 * If we don't have anything left in the lwb list then
2785 * we've had an allocation failure and we need to zero
2786 * out the zil_header blkptr so that we don't end
2787 * up freeing the same block twice.
2789 if (list_head(&zilog
->zl_lwb_list
) == NULL
)
2790 BP_ZERO(&zh
->zh_log
);
2792 mutex_exit(&zilog
->zl_lock
);
2797 zil_lwb_cons(void *vbuf
, void *unused
, int kmflag
)
2800 list_create(&lwb
->lwb_waiters
, sizeof (zil_commit_waiter_t
),
2801 offsetof(zil_commit_waiter_t
, zcw_node
));
2802 avl_create(&lwb
->lwb_vdev_tree
, zil_lwb_vdev_compare
,
2803 sizeof (zil_vdev_node_t
), offsetof(zil_vdev_node_t
, zv_node
));
2804 mutex_init(&lwb
->lwb_vdev_lock
, NULL
, MUTEX_DEFAULT
, NULL
);
2810 zil_lwb_dest(void *vbuf
, void *unused
)
2813 mutex_destroy(&lwb
->lwb_vdev_lock
);
2814 avl_destroy(&lwb
->lwb_vdev_tree
);
2815 list_destroy(&lwb
->lwb_waiters
);
2821 zil_lwb_cache
= kmem_cache_create("zil_lwb_cache",
2822 sizeof (lwb_t
), 0, zil_lwb_cons
, zil_lwb_dest
, NULL
, NULL
, NULL
, 0);
2824 zil_zcw_cache
= kmem_cache_create("zil_zcw_cache",
2825 sizeof (zil_commit_waiter_t
), 0, NULL
, NULL
, NULL
, NULL
, NULL
, 0);
2831 kmem_cache_destroy(zil_zcw_cache
);
2832 kmem_cache_destroy(zil_lwb_cache
);
2836 zil_set_sync(zilog_t
*zilog
, uint64_t sync
)
2838 zilog
->zl_sync
= sync
;
2842 zil_set_logbias(zilog_t
*zilog
, uint64_t logbias
)
2844 zilog
->zl_logbias
= logbias
;
2848 zil_alloc(objset_t
*os
, zil_header_t
*zh_phys
)
2852 zilog
= kmem_zalloc(sizeof (zilog_t
), KM_SLEEP
);
2854 zilog
->zl_header
= zh_phys
;
2856 zilog
->zl_spa
= dmu_objset_spa(os
);
2857 zilog
->zl_dmu_pool
= dmu_objset_pool(os
);
2858 zilog
->zl_destroy_txg
= TXG_INITIAL
- 1;
2859 zilog
->zl_logbias
= dmu_objset_logbias(os
);
2860 zilog
->zl_sync
= dmu_objset_syncprop(os
);
2861 zilog
->zl_dirty_max_txg
= 0;
2862 zilog
->zl_last_lwb_opened
= NULL
;
2863 zilog
->zl_last_lwb_latency
= 0;
2865 mutex_init(&zilog
->zl_lock
, NULL
, MUTEX_DEFAULT
, NULL
);
2866 mutex_init(&zilog
->zl_issuer_lock
, NULL
, MUTEX_DEFAULT
, NULL
);
2868 for (int i
= 0; i
< TXG_SIZE
; i
++) {
2869 mutex_init(&zilog
->zl_itxg
[i
].itxg_lock
, NULL
,
2870 MUTEX_DEFAULT
, NULL
);
2873 list_create(&zilog
->zl_lwb_list
, sizeof (lwb_t
),
2874 offsetof(lwb_t
, lwb_node
));
2876 list_create(&zilog
->zl_itx_commit_list
, sizeof (itx_t
),
2877 offsetof(itx_t
, itx_node
));
2879 cv_init(&zilog
->zl_cv_suspend
, NULL
, CV_DEFAULT
, NULL
);
2885 zil_free(zilog_t
*zilog
)
2887 zilog
->zl_stop_sync
= 1;
2889 ASSERT0(zilog
->zl_suspend
);
2890 ASSERT0(zilog
->zl_suspending
);
2892 ASSERT(list_is_empty(&zilog
->zl_lwb_list
));
2893 list_destroy(&zilog
->zl_lwb_list
);
2895 ASSERT(list_is_empty(&zilog
->zl_itx_commit_list
));
2896 list_destroy(&zilog
->zl_itx_commit_list
);
2898 for (int i
= 0; i
< TXG_SIZE
; i
++) {
2900 * It's possible for an itx to be generated that doesn't dirty
2901 * a txg (e.g. ztest TX_TRUNCATE). So there's no zil_clean()
2902 * callback to remove the entry. We remove those here.
2904 * Also free up the ziltest itxs.
2906 if (zilog
->zl_itxg
[i
].itxg_itxs
)
2907 zil_itxg_clean(zilog
->zl_itxg
[i
].itxg_itxs
);
2908 mutex_destroy(&zilog
->zl_itxg
[i
].itxg_lock
);
2911 mutex_destroy(&zilog
->zl_issuer_lock
);
2912 mutex_destroy(&zilog
->zl_lock
);
2914 cv_destroy(&zilog
->zl_cv_suspend
);
2916 kmem_free(zilog
, sizeof (zilog_t
));
2920 * Open an intent log.
2923 zil_open(objset_t
*os
, zil_get_data_t
*get_data
)
2925 zilog_t
*zilog
= dmu_objset_zil(os
);
2927 ASSERT3P(zilog
->zl_get_data
, ==, NULL
);
2928 ASSERT3P(zilog
->zl_last_lwb_opened
, ==, NULL
);
2929 ASSERT(list_is_empty(&zilog
->zl_lwb_list
));
2931 zilog
->zl_get_data
= get_data
;
2937 * Close an intent log.
2940 zil_close(zilog_t
*zilog
)
2945 if (!dmu_objset_is_snapshot(zilog
->zl_os
)) {
2946 zil_commit(zilog
, 0);
2948 ASSERT3P(list_tail(&zilog
->zl_lwb_list
), ==, NULL
);
2949 ASSERT0(zilog
->zl_dirty_max_txg
);
2950 ASSERT3B(zilog_is_dirty(zilog
), ==, B_FALSE
);
2953 mutex_enter(&zilog
->zl_lock
);
2954 lwb
= list_tail(&zilog
->zl_lwb_list
);
2956 txg
= zilog
->zl_dirty_max_txg
;
2958 txg
= MAX(zilog
->zl_dirty_max_txg
, lwb
->lwb_max_txg
);
2959 mutex_exit(&zilog
->zl_lock
);
2962 * We need to use txg_wait_synced() to wait long enough for the
2963 * ZIL to be clean, and to wait for all pending lwbs to be
2967 txg_wait_synced(zilog
->zl_dmu_pool
, txg
);
2969 if (zilog_is_dirty(zilog
))
2970 zfs_dbgmsg("zil (%p) is dirty, txg %llu", zilog
, txg
);
2971 VERIFY(!zilog_is_dirty(zilog
));
2973 zilog
->zl_get_data
= NULL
;
2976 * We should have only one lwb left on the list; remove it now.
2978 mutex_enter(&zilog
->zl_lock
);
2979 lwb
= list_head(&zilog
->zl_lwb_list
);
2981 ASSERT3P(lwb
, ==, list_tail(&zilog
->zl_lwb_list
));
2982 ASSERT3S(lwb
->lwb_state
, !=, LWB_STATE_ISSUED
);
2983 list_remove(&zilog
->zl_lwb_list
, lwb
);
2984 zio_buf_free(lwb
->lwb_buf
, lwb
->lwb_sz
);
2985 zil_free_lwb(zilog
, lwb
);
2987 mutex_exit(&zilog
->zl_lock
);
2990 static char *suspend_tag
= "zil suspending";
2993 * Suspend an intent log. While in suspended mode, we still honor
2994 * synchronous semantics, but we rely on txg_wait_synced() to do it.
2995 * On old version pools, we suspend the log briefly when taking a
2996 * snapshot so that it will have an empty intent log.
2998 * Long holds are not really intended to be used the way we do here --
2999 * held for such a short time. A concurrent caller of dsl_dataset_long_held()
3000 * could fail. Therefore we take pains to only put a long hold if it is
3001 * actually necessary. Fortunately, it will only be necessary if the
3002 * objset is currently mounted (or the ZVOL equivalent). In that case it
3003 * will already have a long hold, so we are not really making things any worse.
3005 * Ideally, we would locate the existing long-holder (i.e. the zfsvfs_t or
3006 * zvol_state_t), and use their mechanism to prevent their hold from being
3007 * dropped (e.g. VFS_HOLD()). However, that would be even more pain for
3010 * if cookiep == NULL, this does both the suspend & resume.
3011 * Otherwise, it returns with the dataset "long held", and the cookie
3012 * should be passed into zil_resume().
3015 zil_suspend(const char *osname
, void **cookiep
)
3019 const zil_header_t
*zh
;
3022 error
= dmu_objset_hold(osname
, suspend_tag
, &os
);
3025 zilog
= dmu_objset_zil(os
);
3027 mutex_enter(&zilog
->zl_lock
);
3028 zh
= zilog
->zl_header
;
3030 if (zh
->zh_flags
& ZIL_REPLAY_NEEDED
) { /* unplayed log */
3031 mutex_exit(&zilog
->zl_lock
);
3032 dmu_objset_rele(os
, suspend_tag
);
3033 return (SET_ERROR(EBUSY
));
3037 * Don't put a long hold in the cases where we can avoid it. This
3038 * is when there is no cookie so we are doing a suspend & resume
3039 * (i.e. called from zil_vdev_offline()), and there's nothing to do
3040 * for the suspend because it's already suspended, or there's no ZIL.
3042 if (cookiep
== NULL
&& !zilog
->zl_suspending
&&
3043 (zilog
->zl_suspend
> 0 || BP_IS_HOLE(&zh
->zh_log
))) {
3044 mutex_exit(&zilog
->zl_lock
);
3045 dmu_objset_rele(os
, suspend_tag
);
3049 dsl_dataset_long_hold(dmu_objset_ds(os
), suspend_tag
);
3050 dsl_pool_rele(dmu_objset_pool(os
), suspend_tag
);
3052 zilog
->zl_suspend
++;
3054 if (zilog
->zl_suspend
> 1) {
3056 * Someone else is already suspending it.
3057 * Just wait for them to finish.
3060 while (zilog
->zl_suspending
)
3061 cv_wait(&zilog
->zl_cv_suspend
, &zilog
->zl_lock
);
3062 mutex_exit(&zilog
->zl_lock
);
3064 if (cookiep
== NULL
)
3072 * If there is no pointer to an on-disk block, this ZIL must not
3073 * be active (e.g. filesystem not mounted), so there's nothing
3076 if (BP_IS_HOLE(&zh
->zh_log
)) {
3077 ASSERT(cookiep
!= NULL
); /* fast path already handled */
3080 mutex_exit(&zilog
->zl_lock
);
3084 zilog
->zl_suspending
= B_TRUE
;
3085 mutex_exit(&zilog
->zl_lock
);
3088 * We need to use zil_commit_impl to ensure we wait for all
3089 * LWB_STATE_OPENED and LWB_STATE_ISSUED lwb's to be committed
3090 * to disk before proceeding. If we used zil_commit instead, it
3091 * would just call txg_wait_synced(), because zl_suspend is set.
3092 * txg_wait_synced() doesn't wait for these lwb's to be
3093 * LWB_STATE_DONE before returning.
3095 zil_commit_impl(zilog
, 0);
3098 * Now that we've ensured all lwb's are LWB_STATE_DONE, we use
3099 * txg_wait_synced() to ensure the data from the zilog has
3100 * migrated to the main pool before calling zil_destroy().
3102 txg_wait_synced(zilog
->zl_dmu_pool
, 0);
3104 zil_destroy(zilog
, B_FALSE
);
3106 mutex_enter(&zilog
->zl_lock
);
3107 zilog
->zl_suspending
= B_FALSE
;
3108 cv_broadcast(&zilog
->zl_cv_suspend
);
3109 mutex_exit(&zilog
->zl_lock
);
3111 if (cookiep
== NULL
)
3119 zil_resume(void *cookie
)
3121 objset_t
*os
= cookie
;
3122 zilog_t
*zilog
= dmu_objset_zil(os
);
3124 mutex_enter(&zilog
->zl_lock
);
3125 ASSERT(zilog
->zl_suspend
!= 0);
3126 zilog
->zl_suspend
--;
3127 mutex_exit(&zilog
->zl_lock
);
3128 dsl_dataset_long_rele(dmu_objset_ds(os
), suspend_tag
);
3129 dsl_dataset_rele(dmu_objset_ds(os
), suspend_tag
);
3132 typedef struct zil_replay_arg
{
3133 zil_replay_func_t
**zr_replay
;
3135 boolean_t zr_byteswap
;
3140 zil_replay_error(zilog_t
*zilog
, lr_t
*lr
, int error
)
3142 char name
[ZFS_MAX_DATASET_NAME_LEN
];
3144 zilog
->zl_replaying_seq
--; /* didn't actually replay this one */
3146 dmu_objset_name(zilog
->zl_os
, name
);
3148 cmn_err(CE_WARN
, "ZFS replay transaction error %d, "
3149 "dataset %s, seq 0x%llx, txtype %llu %s\n", error
, name
,
3150 (u_longlong_t
)lr
->lrc_seq
,
3151 (u_longlong_t
)(lr
->lrc_txtype
& ~TX_CI
),
3152 (lr
->lrc_txtype
& TX_CI
) ? "CI" : "");
3158 zil_replay_log_record(zilog_t
*zilog
, lr_t
*lr
, void *zra
, uint64_t claim_txg
)
3160 zil_replay_arg_t
*zr
= zra
;
3161 const zil_header_t
*zh
= zilog
->zl_header
;
3162 uint64_t reclen
= lr
->lrc_reclen
;
3163 uint64_t txtype
= lr
->lrc_txtype
;
3166 zilog
->zl_replaying_seq
= lr
->lrc_seq
;
3168 if (lr
->lrc_seq
<= zh
->zh_replay_seq
) /* already replayed */
3171 if (lr
->lrc_txg
< claim_txg
) /* already committed */
3174 /* Strip case-insensitive bit, still present in log record */
3177 if (txtype
== 0 || txtype
>= TX_MAX_TYPE
)
3178 return (zil_replay_error(zilog
, lr
, EINVAL
));
3181 * If this record type can be logged out of order, the object
3182 * (lr_foid) may no longer exist. That's legitimate, not an error.
3184 if (TX_OOO(txtype
)) {
3185 error
= dmu_object_info(zilog
->zl_os
,
3186 ((lr_ooo_t
*)lr
)->lr_foid
, NULL
);
3187 if (error
== ENOENT
|| error
== EEXIST
)
3192 * Make a copy of the data so we can revise and extend it.
3194 bcopy(lr
, zr
->zr_lr
, reclen
);
3197 * If this is a TX_WRITE with a blkptr, suck in the data.
3199 if (txtype
== TX_WRITE
&& reclen
== sizeof (lr_write_t
)) {
3200 error
= zil_read_log_data(zilog
, (lr_write_t
*)lr
,
3201 zr
->zr_lr
+ reclen
);
3203 return (zil_replay_error(zilog
, lr
, error
));
3207 * The log block containing this lr may have been byteswapped
3208 * so that we can easily examine common fields like lrc_txtype.
3209 * However, the log is a mix of different record types, and only the
3210 * replay vectors know how to byteswap their records. Therefore, if
3211 * the lr was byteswapped, undo it before invoking the replay vector.
3213 if (zr
->zr_byteswap
)
3214 byteswap_uint64_array(zr
->zr_lr
, reclen
);
3217 * We must now do two things atomically: replay this log record,
3218 * and update the log header sequence number to reflect the fact that
3219 * we did so. At the end of each replay function the sequence number
3220 * is updated if we are in replay mode.
3222 error
= zr
->zr_replay
[txtype
](zr
->zr_arg
, zr
->zr_lr
, zr
->zr_byteswap
);
3225 * The DMU's dnode layer doesn't see removes until the txg
3226 * commits, so a subsequent claim can spuriously fail with
3227 * EEXIST. So if we receive any error we try syncing out
3228 * any removes then retry the transaction. Note that we
3229 * specify B_FALSE for byteswap now, so we don't do it twice.
3231 txg_wait_synced(spa_get_dsl(zilog
->zl_spa
), 0);
3232 error
= zr
->zr_replay
[txtype
](zr
->zr_arg
, zr
->zr_lr
, B_FALSE
);
3234 return (zil_replay_error(zilog
, lr
, error
));
3241 zil_incr_blks(zilog_t
*zilog
, blkptr_t
*bp
, void *arg
, uint64_t claim_txg
)
3243 zilog
->zl_replay_blks
++;
3249 * If this dataset has a non-empty intent log, replay it and destroy it.
3252 zil_replay(objset_t
*os
, void *arg
, zil_replay_func_t
*replay_func
[TX_MAX_TYPE
])
3254 zilog_t
*zilog
= dmu_objset_zil(os
);
3255 const zil_header_t
*zh
= zilog
->zl_header
;
3256 zil_replay_arg_t zr
;
3258 if ((zh
->zh_flags
& ZIL_REPLAY_NEEDED
) == 0) {
3259 zil_destroy(zilog
, B_TRUE
);
3263 zr
.zr_replay
= replay_func
;
3265 zr
.zr_byteswap
= BP_SHOULD_BYTESWAP(&zh
->zh_log
);
3266 zr
.zr_lr
= kmem_alloc(2 * SPA_MAXBLOCKSIZE
, KM_SLEEP
);
3269 * Wait for in-progress removes to sync before starting replay.
3271 txg_wait_synced(zilog
->zl_dmu_pool
, 0);
3273 zilog
->zl_replay
= B_TRUE
;
3274 zilog
->zl_replay_time
= ddi_get_lbolt();
3275 ASSERT(zilog
->zl_replay_blks
== 0);
3276 (void) zil_parse(zilog
, zil_incr_blks
, zil_replay_log_record
, &zr
,
3278 kmem_free(zr
.zr_lr
, 2 * SPA_MAXBLOCKSIZE
);
3280 zil_destroy(zilog
, B_FALSE
);
3281 txg_wait_synced(zilog
->zl_dmu_pool
, zilog
->zl_destroy_txg
);
3282 zilog
->zl_replay
= B_FALSE
;
3286 zil_replaying(zilog_t
*zilog
, dmu_tx_t
*tx
)
3288 if (zilog
->zl_sync
== ZFS_SYNC_DISABLED
)
3291 if (zilog
->zl_replay
) {
3292 dsl_dataset_dirty(dmu_objset_ds(zilog
->zl_os
), tx
);
3293 zilog
->zl_replayed_seq
[dmu_tx_get_txg(tx
) & TXG_MASK
] =
3294 zilog
->zl_replaying_seq
;
3303 zil_reset(const char *osname
, void *arg
)
3307 error
= zil_suspend(osname
, NULL
);
3309 return (SET_ERROR(EEXIST
));