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, 2018 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 * Disable the DKIOCFLUSHWRITECACHE commands that are normally sent to
99 * the disk(s) by the ZIL after an LWB write has completed. Setting this
100 * will cause ZIL corruption on power loss if a volatile out-of-order
101 * write cache is enabled.
103 boolean_t zil_nocacheflush
= B_FALSE
;
106 * Limit SLOG write size per commit executed with synchronous priority.
107 * Any writes above that will be executed with lower (asynchronous) priority
108 * to limit potential SLOG device abuse by single active ZIL writer.
110 uint64_t zil_slog_bulk
= 768 * 1024;
112 static kmem_cache_t
*zil_lwb_cache
;
113 static kmem_cache_t
*zil_zcw_cache
;
115 static void zil_async_to_sync(zilog_t
*zilog
, uint64_t foid
);
117 #define LWB_EMPTY(lwb) ((BP_GET_LSIZE(&lwb->lwb_blk) - \
118 sizeof (zil_chain_t)) == (lwb->lwb_sz - lwb->lwb_nused))
121 zil_bp_compare(const void *x1
, const void *x2
)
123 const dva_t
*dva1
= &((zil_bp_node_t
*)x1
)->zn_dva
;
124 const dva_t
*dva2
= &((zil_bp_node_t
*)x2
)->zn_dva
;
126 int cmp
= TREE_CMP(DVA_GET_VDEV(dva1
), DVA_GET_VDEV(dva2
));
130 return (TREE_CMP(DVA_GET_OFFSET(dva1
), DVA_GET_OFFSET(dva2
)));
134 zil_bp_tree_init(zilog_t
*zilog
)
136 avl_create(&zilog
->zl_bp_tree
, zil_bp_compare
,
137 sizeof (zil_bp_node_t
), offsetof(zil_bp_node_t
, zn_node
));
141 zil_bp_tree_fini(zilog_t
*zilog
)
143 avl_tree_t
*t
= &zilog
->zl_bp_tree
;
147 while ((zn
= avl_destroy_nodes(t
, &cookie
)) != NULL
)
148 kmem_free(zn
, sizeof (zil_bp_node_t
));
154 zil_bp_tree_add(zilog_t
*zilog
, const blkptr_t
*bp
)
156 avl_tree_t
*t
= &zilog
->zl_bp_tree
;
161 if (BP_IS_EMBEDDED(bp
))
164 dva
= BP_IDENTITY(bp
);
166 if (avl_find(t
, dva
, &where
) != NULL
)
167 return (SET_ERROR(EEXIST
));
169 zn
= kmem_alloc(sizeof (zil_bp_node_t
), KM_SLEEP
);
171 avl_insert(t
, zn
, where
);
176 static zil_header_t
*
177 zil_header_in_syncing_context(zilog_t
*zilog
)
179 return ((zil_header_t
*)zilog
->zl_header
);
183 zil_init_log_chain(zilog_t
*zilog
, blkptr_t
*bp
)
185 zio_cksum_t
*zc
= &bp
->blk_cksum
;
187 zc
->zc_word
[ZIL_ZC_GUID_0
] = spa_get_random(-1ULL);
188 zc
->zc_word
[ZIL_ZC_GUID_1
] = spa_get_random(-1ULL);
189 zc
->zc_word
[ZIL_ZC_OBJSET
] = dmu_objset_id(zilog
->zl_os
);
190 zc
->zc_word
[ZIL_ZC_SEQ
] = 1ULL;
194 * Read a log block and make sure it's valid.
197 zil_read_log_block(zilog_t
*zilog
, boolean_t decrypt
, const blkptr_t
*bp
,
198 blkptr_t
*nbp
, void *dst
, char **end
)
200 enum zio_flag zio_flags
= ZIO_FLAG_CANFAIL
;
201 arc_flags_t aflags
= ARC_FLAG_WAIT
;
202 arc_buf_t
*abuf
= NULL
;
206 if (zilog
->zl_header
->zh_claim_txg
== 0)
207 zio_flags
|= ZIO_FLAG_SPECULATIVE
| ZIO_FLAG_SCRUB
;
209 if (!(zilog
->zl_header
->zh_flags
& ZIL_CLAIM_LR_SEQ_VALID
))
210 zio_flags
|= ZIO_FLAG_SPECULATIVE
;
213 zio_flags
|= ZIO_FLAG_RAW
;
215 SET_BOOKMARK(&zb
, bp
->blk_cksum
.zc_word
[ZIL_ZC_OBJSET
],
216 ZB_ZIL_OBJECT
, ZB_ZIL_LEVEL
, bp
->blk_cksum
.zc_word
[ZIL_ZC_SEQ
]);
218 error
= arc_read(NULL
, zilog
->zl_spa
, bp
, arc_getbuf_func
,
219 &abuf
, ZIO_PRIORITY_SYNC_READ
, zio_flags
, &aflags
, &zb
);
222 zio_cksum_t cksum
= bp
->blk_cksum
;
225 * Validate the checksummed log block.
227 * Sequence numbers should be... sequential. The checksum
228 * verifier for the next block should be bp's checksum plus 1.
230 * Also check the log chain linkage and size used.
232 cksum
.zc_word
[ZIL_ZC_SEQ
]++;
234 if (BP_GET_CHECKSUM(bp
) == ZIO_CHECKSUM_ZILOG2
) {
235 zil_chain_t
*zilc
= abuf
->b_data
;
236 char *lr
= (char *)(zilc
+ 1);
237 uint64_t len
= zilc
->zc_nused
- sizeof (zil_chain_t
);
239 if (bcmp(&cksum
, &zilc
->zc_next_blk
.blk_cksum
,
240 sizeof (cksum
)) || BP_IS_HOLE(&zilc
->zc_next_blk
)) {
241 error
= SET_ERROR(ECKSUM
);
243 ASSERT3U(len
, <=, SPA_OLD_MAXBLOCKSIZE
);
245 *end
= (char *)dst
+ len
;
246 *nbp
= zilc
->zc_next_blk
;
249 char *lr
= abuf
->b_data
;
250 uint64_t size
= BP_GET_LSIZE(bp
);
251 zil_chain_t
*zilc
= (zil_chain_t
*)(lr
+ size
) - 1;
253 if (bcmp(&cksum
, &zilc
->zc_next_blk
.blk_cksum
,
254 sizeof (cksum
)) || BP_IS_HOLE(&zilc
->zc_next_blk
) ||
255 (zilc
->zc_nused
> (size
- sizeof (*zilc
)))) {
256 error
= SET_ERROR(ECKSUM
);
258 ASSERT3U(zilc
->zc_nused
, <=,
259 SPA_OLD_MAXBLOCKSIZE
);
260 bcopy(lr
, dst
, zilc
->zc_nused
);
261 *end
= (char *)dst
+ zilc
->zc_nused
;
262 *nbp
= zilc
->zc_next_blk
;
266 arc_buf_destroy(abuf
, &abuf
);
273 * Read a TX_WRITE log data block.
276 zil_read_log_data(zilog_t
*zilog
, const lr_write_t
*lr
, void *wbuf
)
278 enum zio_flag zio_flags
= ZIO_FLAG_CANFAIL
;
279 const blkptr_t
*bp
= &lr
->lr_blkptr
;
280 arc_flags_t aflags
= ARC_FLAG_WAIT
;
281 arc_buf_t
*abuf
= NULL
;
285 if (BP_IS_HOLE(bp
)) {
287 bzero(wbuf
, MAX(BP_GET_LSIZE(bp
), lr
->lr_length
));
291 if (zilog
->zl_header
->zh_claim_txg
== 0)
292 zio_flags
|= ZIO_FLAG_SPECULATIVE
| ZIO_FLAG_SCRUB
;
295 * If we are not using the resulting data, we are just checking that
296 * it hasn't been corrupted so we don't need to waste CPU time
297 * decompressing and decrypting it.
300 zio_flags
|= ZIO_FLAG_RAW
;
302 SET_BOOKMARK(&zb
, dmu_objset_id(zilog
->zl_os
), lr
->lr_foid
,
303 ZB_ZIL_LEVEL
, lr
->lr_offset
/ BP_GET_LSIZE(bp
));
305 error
= arc_read(NULL
, zilog
->zl_spa
, bp
, arc_getbuf_func
, &abuf
,
306 ZIO_PRIORITY_SYNC_READ
, zio_flags
, &aflags
, &zb
);
310 bcopy(abuf
->b_data
, wbuf
, arc_buf_size(abuf
));
311 arc_buf_destroy(abuf
, &abuf
);
318 * Parse the intent log, and call parse_func for each valid record within.
321 zil_parse(zilog_t
*zilog
, zil_parse_blk_func_t
*parse_blk_func
,
322 zil_parse_lr_func_t
*parse_lr_func
, void *arg
, uint64_t txg
,
325 const zil_header_t
*zh
= zilog
->zl_header
;
326 boolean_t claimed
= !!zh
->zh_claim_txg
;
327 uint64_t claim_blk_seq
= claimed
? zh
->zh_claim_blk_seq
: UINT64_MAX
;
328 uint64_t claim_lr_seq
= claimed
? zh
->zh_claim_lr_seq
: UINT64_MAX
;
329 uint64_t max_blk_seq
= 0;
330 uint64_t max_lr_seq
= 0;
331 uint64_t blk_count
= 0;
332 uint64_t lr_count
= 0;
333 blkptr_t blk
, next_blk
;
338 * Old logs didn't record the maximum zh_claim_lr_seq.
340 if (!(zh
->zh_flags
& ZIL_CLAIM_LR_SEQ_VALID
))
341 claim_lr_seq
= UINT64_MAX
;
344 * Starting at the block pointed to by zh_log we read the log chain.
345 * For each block in the chain we strongly check that block to
346 * ensure its validity. We stop when an invalid block is found.
347 * For each block pointer in the chain we call parse_blk_func().
348 * For each record in each valid block we call parse_lr_func().
349 * If the log has been claimed, stop if we encounter a sequence
350 * number greater than the highest claimed sequence number.
352 lrbuf
= zio_buf_alloc(SPA_OLD_MAXBLOCKSIZE
);
353 zil_bp_tree_init(zilog
);
355 for (blk
= zh
->zh_log
; !BP_IS_HOLE(&blk
); blk
= next_blk
) {
356 uint64_t blk_seq
= blk
.blk_cksum
.zc_word
[ZIL_ZC_SEQ
];
360 if (blk_seq
> claim_blk_seq
)
363 error
= parse_blk_func(zilog
, &blk
, arg
, txg
);
366 ASSERT3U(max_blk_seq
, <, blk_seq
);
367 max_blk_seq
= blk_seq
;
370 if (max_lr_seq
== claim_lr_seq
&& max_blk_seq
== claim_blk_seq
)
373 error
= zil_read_log_block(zilog
, decrypt
, &blk
, &next_blk
,
378 for (lrp
= lrbuf
; lrp
< end
; lrp
+= reclen
) {
379 lr_t
*lr
= (lr_t
*)lrp
;
380 reclen
= lr
->lrc_reclen
;
381 ASSERT3U(reclen
, >=, sizeof (lr_t
));
382 if (lr
->lrc_seq
> claim_lr_seq
)
385 error
= parse_lr_func(zilog
, lr
, arg
, txg
);
388 ASSERT3U(max_lr_seq
, <, lr
->lrc_seq
);
389 max_lr_seq
= lr
->lrc_seq
;
394 zilog
->zl_parse_error
= error
;
395 zilog
->zl_parse_blk_seq
= max_blk_seq
;
396 zilog
->zl_parse_lr_seq
= max_lr_seq
;
397 zilog
->zl_parse_blk_count
= blk_count
;
398 zilog
->zl_parse_lr_count
= lr_count
;
400 ASSERT(!claimed
|| !(zh
->zh_flags
& ZIL_CLAIM_LR_SEQ_VALID
) ||
401 (max_blk_seq
== claim_blk_seq
&& max_lr_seq
== claim_lr_seq
) ||
402 (decrypt
&& error
== EIO
));
404 zil_bp_tree_fini(zilog
);
405 zio_buf_free(lrbuf
, SPA_OLD_MAXBLOCKSIZE
);
412 zil_clear_log_block(zilog_t
*zilog
, blkptr_t
*bp
, void *tx
, uint64_t first_txg
)
414 ASSERT(!BP_IS_HOLE(bp
));
417 * As we call this function from the context of a rewind to a
418 * checkpoint, each ZIL block whose txg is later than the txg
419 * that we rewind to is invalid. Thus, we return -1 so
420 * zil_parse() doesn't attempt to read it.
422 if (bp
->blk_birth
>= first_txg
)
425 if (zil_bp_tree_add(zilog
, bp
) != 0)
428 zio_free(zilog
->zl_spa
, first_txg
, bp
);
434 zil_noop_log_record(zilog_t
*zilog
, lr_t
*lrc
, void *tx
, uint64_t first_txg
)
440 zil_claim_log_block(zilog_t
*zilog
, blkptr_t
*bp
, void *tx
, uint64_t first_txg
)
443 * Claim log block if not already committed and not already claimed.
444 * If tx == NULL, just verify that the block is claimable.
446 if (BP_IS_HOLE(bp
) || bp
->blk_birth
< first_txg
||
447 zil_bp_tree_add(zilog
, bp
) != 0)
450 return (zio_wait(zio_claim(NULL
, zilog
->zl_spa
,
451 tx
== NULL
? 0 : first_txg
, bp
, spa_claim_notify
, NULL
,
452 ZIO_FLAG_CANFAIL
| ZIO_FLAG_SPECULATIVE
| ZIO_FLAG_SCRUB
)));
456 zil_claim_log_record(zilog_t
*zilog
, lr_t
*lrc
, void *tx
, uint64_t first_txg
)
458 lr_write_t
*lr
= (lr_write_t
*)lrc
;
461 if (lrc
->lrc_txtype
!= TX_WRITE
)
465 * If the block is not readable, don't claim it. This can happen
466 * in normal operation when a log block is written to disk before
467 * some of the dmu_sync() blocks it points to. In this case, the
468 * transaction cannot have been committed to anyone (we would have
469 * waited for all writes to be stable first), so it is semantically
470 * correct to declare this the end of the log.
472 if (lr
->lr_blkptr
.blk_birth
>= first_txg
) {
473 error
= zil_read_log_data(zilog
, lr
, NULL
);
478 return (zil_claim_log_block(zilog
, &lr
->lr_blkptr
, tx
, first_txg
));
483 zil_free_log_block(zilog_t
*zilog
, blkptr_t
*bp
, void *tx
, uint64_t claim_txg
)
485 zio_free(zilog
->zl_spa
, dmu_tx_get_txg(tx
), bp
);
491 zil_free_log_record(zilog_t
*zilog
, lr_t
*lrc
, void *tx
, uint64_t claim_txg
)
493 lr_write_t
*lr
= (lr_write_t
*)lrc
;
494 blkptr_t
*bp
= &lr
->lr_blkptr
;
497 * If we previously claimed it, we need to free it.
499 if (claim_txg
!= 0 && lrc
->lrc_txtype
== TX_WRITE
&&
500 bp
->blk_birth
>= claim_txg
&& zil_bp_tree_add(zilog
, bp
) == 0 &&
502 zio_free(zilog
->zl_spa
, dmu_tx_get_txg(tx
), bp
);
508 zil_lwb_vdev_compare(const void *x1
, const void *x2
)
510 const uint64_t v1
= ((zil_vdev_node_t
*)x1
)->zv_vdev
;
511 const uint64_t v2
= ((zil_vdev_node_t
*)x2
)->zv_vdev
;
513 return (TREE_CMP(v1
, v2
));
517 zil_alloc_lwb(zilog_t
*zilog
, blkptr_t
*bp
, boolean_t slog
, uint64_t txg
)
521 lwb
= kmem_cache_alloc(zil_lwb_cache
, KM_SLEEP
);
522 lwb
->lwb_zilog
= zilog
;
524 lwb
->lwb_slog
= slog
;
525 lwb
->lwb_state
= LWB_STATE_CLOSED
;
526 lwb
->lwb_buf
= zio_buf_alloc(BP_GET_LSIZE(bp
));
527 lwb
->lwb_max_txg
= txg
;
528 lwb
->lwb_write_zio
= NULL
;
529 lwb
->lwb_root_zio
= NULL
;
531 lwb
->lwb_issued_timestamp
= 0;
532 if (BP_GET_CHECKSUM(bp
) == ZIO_CHECKSUM_ZILOG2
) {
533 lwb
->lwb_nused
= sizeof (zil_chain_t
);
534 lwb
->lwb_sz
= BP_GET_LSIZE(bp
);
537 lwb
->lwb_sz
= BP_GET_LSIZE(bp
) - sizeof (zil_chain_t
);
540 mutex_enter(&zilog
->zl_lock
);
541 list_insert_tail(&zilog
->zl_lwb_list
, lwb
);
542 mutex_exit(&zilog
->zl_lock
);
544 ASSERT(!MUTEX_HELD(&lwb
->lwb_vdev_lock
));
545 ASSERT(avl_is_empty(&lwb
->lwb_vdev_tree
));
546 VERIFY(list_is_empty(&lwb
->lwb_waiters
));
552 zil_free_lwb(zilog_t
*zilog
, lwb_t
*lwb
)
554 ASSERT(MUTEX_HELD(&zilog
->zl_lock
));
555 ASSERT(!MUTEX_HELD(&lwb
->lwb_vdev_lock
));
556 VERIFY(list_is_empty(&lwb
->lwb_waiters
));
557 ASSERT(avl_is_empty(&lwb
->lwb_vdev_tree
));
558 ASSERT3P(lwb
->lwb_write_zio
, ==, NULL
);
559 ASSERT3P(lwb
->lwb_root_zio
, ==, NULL
);
560 ASSERT3U(lwb
->lwb_max_txg
, <=, spa_syncing_txg(zilog
->zl_spa
));
561 ASSERT(lwb
->lwb_state
== LWB_STATE_CLOSED
||
562 lwb
->lwb_state
== LWB_STATE_FLUSH_DONE
);
565 * Clear the zilog's field to indicate this lwb is no longer
566 * valid, and prevent use-after-free errors.
568 if (zilog
->zl_last_lwb_opened
== lwb
)
569 zilog
->zl_last_lwb_opened
= NULL
;
571 kmem_cache_free(zil_lwb_cache
, lwb
);
575 * Called when we create in-memory log transactions so that we know
576 * to cleanup the itxs at the end of spa_sync().
579 zilog_dirty(zilog_t
*zilog
, uint64_t txg
)
581 dsl_pool_t
*dp
= zilog
->zl_dmu_pool
;
582 dsl_dataset_t
*ds
= dmu_objset_ds(zilog
->zl_os
);
584 ASSERT(spa_writeable(zilog
->zl_spa
));
586 if (ds
->ds_is_snapshot
)
587 panic("dirtying snapshot!");
589 if (txg_list_add(&dp
->dp_dirty_zilogs
, zilog
, txg
)) {
590 /* up the hold count until we can be written out */
591 dmu_buf_add_ref(ds
->ds_dbuf
, zilog
);
593 zilog
->zl_dirty_max_txg
= MAX(txg
, zilog
->zl_dirty_max_txg
);
598 * Determine if the zil is dirty in the specified txg. Callers wanting to
599 * ensure that the dirty state does not change must hold the itxg_lock for
600 * the specified txg. Holding the lock will ensure that the zil cannot be
601 * dirtied (zil_itx_assign) or cleaned (zil_clean) while we check its current
605 zilog_is_dirty_in_txg(zilog_t
*zilog
, uint64_t txg
)
607 dsl_pool_t
*dp
= zilog
->zl_dmu_pool
;
609 if (txg_list_member(&dp
->dp_dirty_zilogs
, zilog
, txg
& TXG_MASK
))
615 * Determine if the zil is dirty. The zil is considered dirty if it has
616 * any pending itx records that have not been cleaned by zil_clean().
619 zilog_is_dirty(zilog_t
*zilog
)
621 dsl_pool_t
*dp
= zilog
->zl_dmu_pool
;
623 for (int t
= 0; t
< TXG_SIZE
; t
++) {
624 if (txg_list_member(&dp
->dp_dirty_zilogs
, zilog
, t
))
631 * Create an on-disk intent log.
634 zil_create(zilog_t
*zilog
)
636 const zil_header_t
*zh
= zilog
->zl_header
;
642 boolean_t slog
= FALSE
;
645 * Wait for any previous destroy to complete.
647 txg_wait_synced(zilog
->zl_dmu_pool
, zilog
->zl_destroy_txg
);
649 ASSERT(zh
->zh_claim_txg
== 0);
650 ASSERT(zh
->zh_replay_seq
== 0);
655 * Allocate an initial log block if:
656 * - there isn't one already
657 * - the existing block is the wrong endianess
659 if (BP_IS_HOLE(&blk
) || BP_SHOULD_BYTESWAP(&blk
)) {
660 tx
= dmu_tx_create(zilog
->zl_os
);
661 VERIFY0(dmu_tx_assign(tx
, TXG_WAIT
));
662 dsl_dataset_dirty(dmu_objset_ds(zilog
->zl_os
), tx
);
663 txg
= dmu_tx_get_txg(tx
);
665 if (!BP_IS_HOLE(&blk
)) {
666 zio_free(zilog
->zl_spa
, txg
, &blk
);
670 error
= zio_alloc_zil(zilog
->zl_spa
, zilog
->zl_os
, txg
, &blk
,
671 NULL
, ZIL_MIN_BLKSZ
, &slog
);
674 zil_init_log_chain(zilog
, &blk
);
678 * Allocate a log write block (lwb) for the first log block.
681 lwb
= zil_alloc_lwb(zilog
, &blk
, slog
, txg
);
684 * If we just allocated the first log block, commit our transaction
685 * and wait for zil_sync() to stuff the block poiner into zh_log.
686 * (zh is part of the MOS, so we cannot modify it in open context.)
690 txg_wait_synced(zilog
->zl_dmu_pool
, txg
);
693 ASSERT(bcmp(&blk
, &zh
->zh_log
, sizeof (blk
)) == 0);
699 * In one tx, free all log blocks and clear the log header. If keep_first
700 * is set, then we're replaying a log with no content. We want to keep the
701 * first block, however, so that the first synchronous transaction doesn't
702 * require a txg_wait_synced() in zil_create(). We don't need to
703 * txg_wait_synced() here either when keep_first is set, because both
704 * zil_create() and zil_destroy() will wait for any in-progress destroys
708 zil_destroy(zilog_t
*zilog
, boolean_t keep_first
)
710 const zil_header_t
*zh
= zilog
->zl_header
;
716 * Wait for any previous destroy to complete.
718 txg_wait_synced(zilog
->zl_dmu_pool
, zilog
->zl_destroy_txg
);
720 zilog
->zl_old_header
= *zh
; /* debugging aid */
722 if (BP_IS_HOLE(&zh
->zh_log
))
725 tx
= dmu_tx_create(zilog
->zl_os
);
726 VERIFY0(dmu_tx_assign(tx
, TXG_WAIT
));
727 dsl_dataset_dirty(dmu_objset_ds(zilog
->zl_os
), tx
);
728 txg
= dmu_tx_get_txg(tx
);
730 mutex_enter(&zilog
->zl_lock
);
732 ASSERT3U(zilog
->zl_destroy_txg
, <, txg
);
733 zilog
->zl_destroy_txg
= txg
;
734 zilog
->zl_keep_first
= keep_first
;
736 if (!list_is_empty(&zilog
->zl_lwb_list
)) {
737 ASSERT(zh
->zh_claim_txg
== 0);
739 while ((lwb
= list_head(&zilog
->zl_lwb_list
)) != NULL
) {
740 list_remove(&zilog
->zl_lwb_list
, lwb
);
741 if (lwb
->lwb_buf
!= NULL
)
742 zio_buf_free(lwb
->lwb_buf
, lwb
->lwb_sz
);
743 zio_free(zilog
->zl_spa
, txg
, &lwb
->lwb_blk
);
744 zil_free_lwb(zilog
, lwb
);
746 } else if (!keep_first
) {
747 zil_destroy_sync(zilog
, tx
);
749 mutex_exit(&zilog
->zl_lock
);
755 zil_destroy_sync(zilog_t
*zilog
, dmu_tx_t
*tx
)
757 ASSERT(list_is_empty(&zilog
->zl_lwb_list
));
758 (void) zil_parse(zilog
, zil_free_log_block
,
759 zil_free_log_record
, tx
, zilog
->zl_header
->zh_claim_txg
, B_FALSE
);
763 zil_claim(dsl_pool_t
*dp
, dsl_dataset_t
*ds
, void *txarg
)
765 dmu_tx_t
*tx
= txarg
;
772 error
= dmu_objset_own_obj(dp
, ds
->ds_object
,
773 DMU_OST_ANY
, B_FALSE
, B_FALSE
, FTAG
, &os
);
776 * EBUSY indicates that the objset is inconsistent, in which
777 * case it can not have a ZIL.
779 if (error
!= EBUSY
) {
780 cmn_err(CE_WARN
, "can't open objset for %llu, error %u",
781 (unsigned long long)ds
->ds_object
, error
);
786 zilog
= dmu_objset_zil(os
);
787 zh
= zil_header_in_syncing_context(zilog
);
788 ASSERT3U(tx
->tx_txg
, ==, spa_first_txg(zilog
->zl_spa
));
789 first_txg
= spa_min_claim_txg(zilog
->zl_spa
);
792 * If the spa_log_state is not set to be cleared, check whether
793 * the current uberblock is a checkpoint one and if the current
794 * header has been claimed before moving on.
796 * If the current uberblock is a checkpointed uberblock then
797 * one of the following scenarios took place:
799 * 1] We are currently rewinding to the checkpoint of the pool.
800 * 2] We crashed in the middle of a checkpoint rewind but we
801 * did manage to write the checkpointed uberblock to the
802 * vdev labels, so when we tried to import the pool again
803 * the checkpointed uberblock was selected from the import
806 * In both cases we want to zero out all the ZIL blocks, except
807 * the ones that have been claimed at the time of the checkpoint
808 * (their zh_claim_txg != 0). The reason is that these blocks
809 * may be corrupted since we may have reused their locations on
810 * disk after we took the checkpoint.
812 * We could try to set spa_log_state to SPA_LOG_CLEAR earlier
813 * when we first figure out whether the current uberblock is
814 * checkpointed or not. Unfortunately, that would discard all
815 * the logs, including the ones that are claimed, and we would
818 if (spa_get_log_state(zilog
->zl_spa
) == SPA_LOG_CLEAR
||
819 (zilog
->zl_spa
->spa_uberblock
.ub_checkpoint_txg
!= 0 &&
820 zh
->zh_claim_txg
== 0)) {
821 if (!BP_IS_HOLE(&zh
->zh_log
)) {
822 (void) zil_parse(zilog
, zil_clear_log_block
,
823 zil_noop_log_record
, tx
, first_txg
, B_FALSE
);
825 BP_ZERO(&zh
->zh_log
);
826 if (os
->os_encrypted
)
827 os
->os_next_write_raw
[tx
->tx_txg
& TXG_MASK
] = B_TRUE
;
828 dsl_dataset_dirty(dmu_objset_ds(os
), tx
);
829 dmu_objset_disown(os
, B_FALSE
, FTAG
);
834 * If we are not rewinding and opening the pool normally, then
835 * the min_claim_txg should be equal to the first txg of the pool.
837 ASSERT3U(first_txg
, ==, spa_first_txg(zilog
->zl_spa
));
840 * Claim all log blocks if we haven't already done so, and remember
841 * the highest claimed sequence number. This ensures that if we can
842 * read only part of the log now (e.g. due to a missing device),
843 * but we can read the entire log later, we will not try to replay
844 * or destroy beyond the last block we successfully claimed.
846 ASSERT3U(zh
->zh_claim_txg
, <=, first_txg
);
847 if (zh
->zh_claim_txg
== 0 && !BP_IS_HOLE(&zh
->zh_log
)) {
848 (void) zil_parse(zilog
, zil_claim_log_block
,
849 zil_claim_log_record
, tx
, first_txg
, B_FALSE
);
850 zh
->zh_claim_txg
= first_txg
;
851 zh
->zh_claim_blk_seq
= zilog
->zl_parse_blk_seq
;
852 zh
->zh_claim_lr_seq
= zilog
->zl_parse_lr_seq
;
853 if (zilog
->zl_parse_lr_count
|| zilog
->zl_parse_blk_count
> 1)
854 zh
->zh_flags
|= ZIL_REPLAY_NEEDED
;
855 zh
->zh_flags
|= ZIL_CLAIM_LR_SEQ_VALID
;
856 if (os
->os_encrypted
)
857 os
->os_next_write_raw
[tx
->tx_txg
& TXG_MASK
] = B_TRUE
;
858 dsl_dataset_dirty(dmu_objset_ds(os
), tx
);
861 ASSERT3U(first_txg
, ==, (spa_last_synced_txg(zilog
->zl_spa
) + 1));
862 dmu_objset_disown(os
, B_FALSE
, FTAG
);
867 * Check the log by walking the log chain.
868 * Checksum errors are ok as they indicate the end of the chain.
869 * Any other error (no device or read failure) returns an error.
873 zil_check_log_chain(dsl_pool_t
*dp
, dsl_dataset_t
*ds
, void *tx
)
882 error
= dmu_objset_from_ds(ds
, &os
);
884 cmn_err(CE_WARN
, "can't open objset %llu, error %d",
885 (unsigned long long)ds
->ds_object
, error
);
889 zilog
= dmu_objset_zil(os
);
890 bp
= (blkptr_t
*)&zilog
->zl_header
->zh_log
;
892 if (!BP_IS_HOLE(bp
)) {
894 boolean_t valid
= B_TRUE
;
897 * Check the first block and determine if it's on a log device
898 * which may have been removed or faulted prior to loading this
899 * pool. If so, there's no point in checking the rest of the
900 * log as its content should have already been synced to the
903 spa_config_enter(os
->os_spa
, SCL_STATE
, FTAG
, RW_READER
);
904 vd
= vdev_lookup_top(os
->os_spa
, DVA_GET_VDEV(&bp
->blk_dva
[0]));
905 if (vd
->vdev_islog
&& vdev_is_dead(vd
))
906 valid
= vdev_log_state_valid(vd
);
907 spa_config_exit(os
->os_spa
, SCL_STATE
, FTAG
);
913 * Check whether the current uberblock is checkpointed (e.g.
914 * we are rewinding) and whether the current header has been
915 * claimed or not. If it hasn't then skip verifying it. We
916 * do this because its ZIL blocks may be part of the pool's
917 * state before the rewind, which is no longer valid.
919 zil_header_t
*zh
= zil_header_in_syncing_context(zilog
);
920 if (zilog
->zl_spa
->spa_uberblock
.ub_checkpoint_txg
!= 0 &&
921 zh
->zh_claim_txg
== 0)
926 * Because tx == NULL, zil_claim_log_block() will not actually claim
927 * any blocks, but just determine whether it is possible to do so.
928 * In addition to checking the log chain, zil_claim_log_block()
929 * will invoke zio_claim() with a done func of spa_claim_notify(),
930 * which will update spa_max_claim_txg. See spa_load() for details.
932 error
= zil_parse(zilog
, zil_claim_log_block
, zil_claim_log_record
, tx
,
933 zilog
->zl_header
->zh_claim_txg
? -1ULL :
934 spa_min_claim_txg(os
->os_spa
), B_FALSE
);
936 return ((error
== ECKSUM
|| error
== ENOENT
) ? 0 : error
);
940 * When an itx is "skipped", this function is used to properly mark the
941 * waiter as "done, and signal any thread(s) waiting on it. An itx can
942 * be skipped (and not committed to an lwb) for a variety of reasons,
943 * one of them being that the itx was committed via spa_sync(), prior to
944 * it being committed to an lwb; this can happen if a thread calling
945 * zil_commit() is racing with spa_sync().
948 zil_commit_waiter_skip(zil_commit_waiter_t
*zcw
)
950 mutex_enter(&zcw
->zcw_lock
);
951 ASSERT3B(zcw
->zcw_done
, ==, B_FALSE
);
952 zcw
->zcw_done
= B_TRUE
;
953 cv_broadcast(&zcw
->zcw_cv
);
954 mutex_exit(&zcw
->zcw_lock
);
958 * This function is used when the given waiter is to be linked into an
959 * lwb's "lwb_waiter" list; i.e. when the itx is committed to the lwb.
960 * At this point, the waiter will no longer be referenced by the itx,
961 * and instead, will be referenced by the lwb.
964 zil_commit_waiter_link_lwb(zil_commit_waiter_t
*zcw
, lwb_t
*lwb
)
967 * The lwb_waiters field of the lwb is protected by the zilog's
968 * zl_lock, thus it must be held when calling this function.
970 ASSERT(MUTEX_HELD(&lwb
->lwb_zilog
->zl_lock
));
972 mutex_enter(&zcw
->zcw_lock
);
973 ASSERT(!list_link_active(&zcw
->zcw_node
));
974 ASSERT3P(zcw
->zcw_lwb
, ==, NULL
);
975 ASSERT3P(lwb
, !=, NULL
);
976 ASSERT(lwb
->lwb_state
== LWB_STATE_OPENED
||
977 lwb
->lwb_state
== LWB_STATE_ISSUED
||
978 lwb
->lwb_state
== LWB_STATE_WRITE_DONE
);
980 list_insert_tail(&lwb
->lwb_waiters
, zcw
);
982 mutex_exit(&zcw
->zcw_lock
);
986 * This function is used when zio_alloc_zil() fails to allocate a ZIL
987 * block, and the given waiter must be linked to the "nolwb waiters"
988 * list inside of zil_process_commit_list().
991 zil_commit_waiter_link_nolwb(zil_commit_waiter_t
*zcw
, list_t
*nolwb
)
993 mutex_enter(&zcw
->zcw_lock
);
994 ASSERT(!list_link_active(&zcw
->zcw_node
));
995 ASSERT3P(zcw
->zcw_lwb
, ==, NULL
);
996 list_insert_tail(nolwb
, zcw
);
997 mutex_exit(&zcw
->zcw_lock
);
1001 zil_lwb_add_block(lwb_t
*lwb
, const blkptr_t
*bp
)
1003 avl_tree_t
*t
= &lwb
->lwb_vdev_tree
;
1005 zil_vdev_node_t
*zv
, zvsearch
;
1006 int ndvas
= BP_GET_NDVAS(bp
);
1009 if (zil_nocacheflush
)
1012 mutex_enter(&lwb
->lwb_vdev_lock
);
1013 for (i
= 0; i
< ndvas
; i
++) {
1014 zvsearch
.zv_vdev
= DVA_GET_VDEV(&bp
->blk_dva
[i
]);
1015 if (avl_find(t
, &zvsearch
, &where
) == NULL
) {
1016 zv
= kmem_alloc(sizeof (*zv
), KM_SLEEP
);
1017 zv
->zv_vdev
= zvsearch
.zv_vdev
;
1018 avl_insert(t
, zv
, where
);
1021 mutex_exit(&lwb
->lwb_vdev_lock
);
1025 zil_lwb_flush_defer(lwb_t
*lwb
, lwb_t
*nlwb
)
1027 avl_tree_t
*src
= &lwb
->lwb_vdev_tree
;
1028 avl_tree_t
*dst
= &nlwb
->lwb_vdev_tree
;
1029 void *cookie
= NULL
;
1030 zil_vdev_node_t
*zv
;
1032 ASSERT3S(lwb
->lwb_state
, ==, LWB_STATE_WRITE_DONE
);
1033 ASSERT3S(nlwb
->lwb_state
, !=, LWB_STATE_WRITE_DONE
);
1034 ASSERT3S(nlwb
->lwb_state
, !=, LWB_STATE_FLUSH_DONE
);
1037 * While 'lwb' is at a point in its lifetime where lwb_vdev_tree does
1038 * not need the protection of lwb_vdev_lock (it will only be modified
1039 * while holding zilog->zl_lock) as its writes and those of its
1040 * children have all completed. The younger 'nlwb' may be waiting on
1041 * future writes to additional vdevs.
1043 mutex_enter(&nlwb
->lwb_vdev_lock
);
1045 * Tear down the 'lwb' vdev tree, ensuring that entries which do not
1046 * exist in 'nlwb' are moved to it, freeing any would-be duplicates.
1048 while ((zv
= avl_destroy_nodes(src
, &cookie
)) != NULL
) {
1051 if (avl_find(dst
, zv
, &where
) == NULL
) {
1052 avl_insert(dst
, zv
, where
);
1054 kmem_free(zv
, sizeof (*zv
));
1057 mutex_exit(&nlwb
->lwb_vdev_lock
);
1061 zil_lwb_add_txg(lwb_t
*lwb
, uint64_t txg
)
1063 lwb
->lwb_max_txg
= MAX(lwb
->lwb_max_txg
, txg
);
1067 * This function is a called after all vdevs associated with a given lwb
1068 * write have completed their DKIOCFLUSHWRITECACHE command; or as soon
1069 * as the lwb write completes, if "zil_nocacheflush" is set. Further,
1070 * all "previous" lwb's will have completed before this function is
1071 * called; i.e. this function is called for all previous lwbs before
1072 * it's called for "this" lwb (enforced via zio the dependencies
1073 * configured in zil_lwb_set_zio_dependency()).
1075 * The intention is for this function to be called as soon as the
1076 * contents of an lwb are considered "stable" on disk, and will survive
1077 * any sudden loss of power. At this point, any threads waiting for the
1078 * lwb to reach this state are signalled, and the "waiter" structures
1079 * are marked "done".
1082 zil_lwb_flush_vdevs_done(zio_t
*zio
)
1084 lwb_t
*lwb
= zio
->io_private
;
1085 zilog_t
*zilog
= lwb
->lwb_zilog
;
1086 dmu_tx_t
*tx
= lwb
->lwb_tx
;
1087 zil_commit_waiter_t
*zcw
;
1089 spa_config_exit(zilog
->zl_spa
, SCL_STATE
, lwb
);
1091 zio_buf_free(lwb
->lwb_buf
, lwb
->lwb_sz
);
1093 mutex_enter(&zilog
->zl_lock
);
1096 * Ensure the lwb buffer pointer is cleared before releasing the
1097 * txg. If we have had an allocation failure and the txg is
1098 * waiting to sync then we want zil_sync() to remove the lwb so
1099 * that it's not picked up as the next new one in
1100 * zil_process_commit_list(). zil_sync() will only remove the
1101 * lwb if lwb_buf is null.
1103 lwb
->lwb_buf
= NULL
;
1106 ASSERT3U(lwb
->lwb_issued_timestamp
, >, 0);
1107 zilog
->zl_last_lwb_latency
= gethrtime() - lwb
->lwb_issued_timestamp
;
1109 lwb
->lwb_root_zio
= NULL
;
1111 ASSERT3S(lwb
->lwb_state
, ==, LWB_STATE_WRITE_DONE
);
1112 lwb
->lwb_state
= LWB_STATE_FLUSH_DONE
;
1114 if (zilog
->zl_last_lwb_opened
== lwb
) {
1116 * Remember the highest committed log sequence number
1117 * for ztest. We only update this value when all the log
1118 * writes succeeded, because ztest wants to ASSERT that
1119 * it got the whole log chain.
1121 zilog
->zl_commit_lr_seq
= zilog
->zl_lr_seq
;
1124 while ((zcw
= list_head(&lwb
->lwb_waiters
)) != NULL
) {
1125 mutex_enter(&zcw
->zcw_lock
);
1127 ASSERT(list_link_active(&zcw
->zcw_node
));
1128 list_remove(&lwb
->lwb_waiters
, zcw
);
1130 ASSERT3P(zcw
->zcw_lwb
, ==, lwb
);
1131 zcw
->zcw_lwb
= NULL
;
1133 zcw
->zcw_zio_error
= zio
->io_error
;
1135 ASSERT3B(zcw
->zcw_done
, ==, B_FALSE
);
1136 zcw
->zcw_done
= B_TRUE
;
1137 cv_broadcast(&zcw
->zcw_cv
);
1139 mutex_exit(&zcw
->zcw_lock
);
1142 mutex_exit(&zilog
->zl_lock
);
1145 * Now that we've written this log block, we have a stable pointer
1146 * to the next block in the chain, so it's OK to let the txg in
1147 * which we allocated the next block sync.
1153 * This is called when an lwb's write zio completes. The callback's
1154 * purpose is to issue the DKIOCFLUSHWRITECACHE commands for the vdevs
1155 * in the lwb's lwb_vdev_tree. The tree will contain the vdevs involved
1156 * in writing out this specific lwb's data, and in the case that cache
1157 * flushes have been deferred, vdevs involved in writing the data for
1158 * previous lwbs. The writes corresponding to all the vdevs in the
1159 * lwb_vdev_tree will have completed by the time this is called, due to
1160 * the zio dependencies configured in zil_lwb_set_zio_dependency(),
1161 * which takes deferred flushes into account. The lwb will be "done"
1162 * once zil_lwb_flush_vdevs_done() is called, which occurs in the zio
1163 * completion callback for the lwb's root zio.
1166 zil_lwb_write_done(zio_t
*zio
)
1168 lwb_t
*lwb
= zio
->io_private
;
1169 spa_t
*spa
= zio
->io_spa
;
1170 zilog_t
*zilog
= lwb
->lwb_zilog
;
1171 avl_tree_t
*t
= &lwb
->lwb_vdev_tree
;
1172 void *cookie
= NULL
;
1173 zil_vdev_node_t
*zv
;
1176 ASSERT3S(spa_config_held(spa
, SCL_STATE
, RW_READER
), !=, 0);
1178 ASSERT(BP_GET_COMPRESS(zio
->io_bp
) == ZIO_COMPRESS_OFF
);
1179 ASSERT(BP_GET_TYPE(zio
->io_bp
) == DMU_OT_INTENT_LOG
);
1180 ASSERT(BP_GET_LEVEL(zio
->io_bp
) == 0);
1181 ASSERT(BP_GET_BYTEORDER(zio
->io_bp
) == ZFS_HOST_BYTEORDER
);
1182 ASSERT(!BP_IS_GANG(zio
->io_bp
));
1183 ASSERT(!BP_IS_HOLE(zio
->io_bp
));
1184 ASSERT(BP_GET_FILL(zio
->io_bp
) == 0);
1186 abd_put(zio
->io_abd
);
1188 mutex_enter(&zilog
->zl_lock
);
1189 ASSERT3S(lwb
->lwb_state
, ==, LWB_STATE_ISSUED
);
1190 lwb
->lwb_state
= LWB_STATE_WRITE_DONE
;
1191 lwb
->lwb_write_zio
= NULL
;
1192 nlwb
= list_next(&zilog
->zl_lwb_list
, lwb
);
1193 mutex_exit(&zilog
->zl_lock
);
1195 if (avl_numnodes(t
) == 0)
1199 * If there was an IO error, we're not going to call zio_flush()
1200 * on these vdevs, so we simply empty the tree and free the
1201 * nodes. We avoid calling zio_flush() since there isn't any
1202 * good reason for doing so, after the lwb block failed to be
1205 if (zio
->io_error
!= 0) {
1206 while ((zv
= avl_destroy_nodes(t
, &cookie
)) != NULL
)
1207 kmem_free(zv
, sizeof (*zv
));
1212 * If this lwb does not have any threads waiting for it to
1213 * complete, we want to defer issuing the DKIOCFLUSHWRITECACHE
1214 * command to the vdevs written to by "this" lwb, and instead
1215 * rely on the "next" lwb to handle the DKIOCFLUSHWRITECACHE
1216 * command for those vdevs. Thus, we merge the vdev tree of
1217 * "this" lwb with the vdev tree of the "next" lwb in the list,
1218 * and assume the "next" lwb will handle flushing the vdevs (or
1219 * deferring the flush(s) again).
1221 * This is a useful performance optimization, especially for
1222 * workloads with lots of async write activity and few sync
1223 * write and/or fsync activity, as it has the potential to
1224 * coalesce multiple flush commands to a vdev into one.
1226 if (list_head(&lwb
->lwb_waiters
) == NULL
&& nlwb
!= NULL
) {
1227 zil_lwb_flush_defer(lwb
, nlwb
);
1228 ASSERT(avl_is_empty(&lwb
->lwb_vdev_tree
));
1232 while ((zv
= avl_destroy_nodes(t
, &cookie
)) != NULL
) {
1233 vdev_t
*vd
= vdev_lookup_top(spa
, zv
->zv_vdev
);
1235 zio_flush(lwb
->lwb_root_zio
, vd
);
1236 kmem_free(zv
, sizeof (*zv
));
1241 zil_lwb_set_zio_dependency(zilog_t
*zilog
, lwb_t
*lwb
)
1243 lwb_t
*last_lwb_opened
= zilog
->zl_last_lwb_opened
;
1245 ASSERT(MUTEX_HELD(&zilog
->zl_issuer_lock
));
1246 ASSERT(MUTEX_HELD(&zilog
->zl_lock
));
1249 * The zilog's "zl_last_lwb_opened" field is used to build the
1250 * lwb/zio dependency chain, which is used to preserve the
1251 * ordering of lwb completions that is required by the semantics
1252 * of the ZIL. Each new lwb zio becomes a parent of the
1253 * "previous" lwb zio, such that the new lwb's zio cannot
1254 * complete until the "previous" lwb's zio completes.
1256 * This is required by the semantics of zil_commit(); the commit
1257 * waiters attached to the lwbs will be woken in the lwb zio's
1258 * completion callback, so this zio dependency graph ensures the
1259 * waiters are woken in the correct order (the same order the
1260 * lwbs were created).
1262 if (last_lwb_opened
!= NULL
&&
1263 last_lwb_opened
->lwb_state
!= LWB_STATE_FLUSH_DONE
) {
1264 ASSERT(last_lwb_opened
->lwb_state
== LWB_STATE_OPENED
||
1265 last_lwb_opened
->lwb_state
== LWB_STATE_ISSUED
||
1266 last_lwb_opened
->lwb_state
== LWB_STATE_WRITE_DONE
);
1268 ASSERT3P(last_lwb_opened
->lwb_root_zio
, !=, NULL
);
1269 zio_add_child(lwb
->lwb_root_zio
,
1270 last_lwb_opened
->lwb_root_zio
);
1273 * If the previous lwb's write hasn't already completed,
1274 * we also want to order the completion of the lwb write
1275 * zios (above, we only order the completion of the lwb
1276 * root zios). This is required because of how we can
1277 * defer the DKIOCFLUSHWRITECACHE commands for each lwb.
1279 * When the DKIOCFLUSHWRITECACHE commands are deferred,
1280 * the previous lwb will rely on this lwb to flush the
1281 * vdevs written to by that previous lwb. Thus, we need
1282 * to ensure this lwb doesn't issue the flush until
1283 * after the previous lwb's write completes. We ensure
1284 * this ordering by setting the zio parent/child
1285 * relationship here.
1287 * Without this relationship on the lwb's write zio,
1288 * it's possible for this lwb's write to complete prior
1289 * to the previous lwb's write completing; and thus, the
1290 * vdevs for the previous lwb would be flushed prior to
1291 * that lwb's data being written to those vdevs (the
1292 * vdevs are flushed in the lwb write zio's completion
1293 * handler, zil_lwb_write_done()).
1295 if (last_lwb_opened
->lwb_state
!= LWB_STATE_WRITE_DONE
) {
1296 ASSERT(last_lwb_opened
->lwb_state
== LWB_STATE_OPENED
||
1297 last_lwb_opened
->lwb_state
== LWB_STATE_ISSUED
);
1299 ASSERT3P(last_lwb_opened
->lwb_write_zio
, !=, NULL
);
1300 zio_add_child(lwb
->lwb_write_zio
,
1301 last_lwb_opened
->lwb_write_zio
);
1308 * This function's purpose is to "open" an lwb such that it is ready to
1309 * accept new itxs being committed to it. To do this, the lwb's zio
1310 * structures are created, and linked to the lwb. This function is
1311 * idempotent; if the passed in lwb has already been opened, this
1312 * function is essentially a no-op.
1315 zil_lwb_write_open(zilog_t
*zilog
, lwb_t
*lwb
)
1317 zbookmark_phys_t zb
;
1318 zio_priority_t prio
;
1320 ASSERT(MUTEX_HELD(&zilog
->zl_issuer_lock
));
1321 ASSERT3P(lwb
, !=, NULL
);
1322 EQUIV(lwb
->lwb_root_zio
== NULL
, lwb
->lwb_state
== LWB_STATE_CLOSED
);
1323 EQUIV(lwb
->lwb_root_zio
!= NULL
, lwb
->lwb_state
== LWB_STATE_OPENED
);
1325 SET_BOOKMARK(&zb
, lwb
->lwb_blk
.blk_cksum
.zc_word
[ZIL_ZC_OBJSET
],
1326 ZB_ZIL_OBJECT
, ZB_ZIL_LEVEL
,
1327 lwb
->lwb_blk
.blk_cksum
.zc_word
[ZIL_ZC_SEQ
]);
1329 if (lwb
->lwb_root_zio
== NULL
) {
1330 abd_t
*lwb_abd
= abd_get_from_buf(lwb
->lwb_buf
,
1331 BP_GET_LSIZE(&lwb
->lwb_blk
));
1333 if (!lwb
->lwb_slog
|| zilog
->zl_cur_used
<= zil_slog_bulk
)
1334 prio
= ZIO_PRIORITY_SYNC_WRITE
;
1336 prio
= ZIO_PRIORITY_ASYNC_WRITE
;
1338 lwb
->lwb_root_zio
= zio_root(zilog
->zl_spa
,
1339 zil_lwb_flush_vdevs_done
, lwb
, ZIO_FLAG_CANFAIL
);
1340 ASSERT3P(lwb
->lwb_root_zio
, !=, NULL
);
1342 lwb
->lwb_write_zio
= zio_rewrite(lwb
->lwb_root_zio
,
1343 zilog
->zl_spa
, 0, &lwb
->lwb_blk
, lwb_abd
,
1344 BP_GET_LSIZE(&lwb
->lwb_blk
), zil_lwb_write_done
, lwb
,
1345 prio
, ZIO_FLAG_CANFAIL
| ZIO_FLAG_DONT_PROPAGATE
, &zb
);
1346 ASSERT3P(lwb
->lwb_write_zio
, !=, NULL
);
1348 lwb
->lwb_state
= LWB_STATE_OPENED
;
1350 mutex_enter(&zilog
->zl_lock
);
1351 zil_lwb_set_zio_dependency(zilog
, lwb
);
1352 zilog
->zl_last_lwb_opened
= lwb
;
1353 mutex_exit(&zilog
->zl_lock
);
1356 ASSERT3P(lwb
->lwb_root_zio
, !=, NULL
);
1357 ASSERT3P(lwb
->lwb_write_zio
, !=, NULL
);
1358 ASSERT3S(lwb
->lwb_state
, ==, LWB_STATE_OPENED
);
1362 * Define a limited set of intent log block sizes.
1364 * These must be a multiple of 4KB. Note only the amount used (again
1365 * aligned to 4KB) actually gets written. However, we can't always just
1366 * allocate SPA_OLD_MAXBLOCKSIZE as the slog space could be exhausted.
1368 uint64_t zil_block_buckets
[] = {
1369 4096, /* non TX_WRITE */
1370 8192+4096, /* data base */
1371 32*1024 + 4096, /* NFS writes */
1376 * Start a log block write and advance to the next log block.
1377 * Calls are serialized.
1380 zil_lwb_write_issue(zilog_t
*zilog
, lwb_t
*lwb
)
1384 spa_t
*spa
= zilog
->zl_spa
;
1388 uint64_t zil_blksz
, wsz
;
1392 ASSERT(MUTEX_HELD(&zilog
->zl_issuer_lock
));
1393 ASSERT3P(lwb
->lwb_root_zio
, !=, NULL
);
1394 ASSERT3P(lwb
->lwb_write_zio
, !=, NULL
);
1395 ASSERT3S(lwb
->lwb_state
, ==, LWB_STATE_OPENED
);
1397 if (BP_GET_CHECKSUM(&lwb
->lwb_blk
) == ZIO_CHECKSUM_ZILOG2
) {
1398 zilc
= (zil_chain_t
*)lwb
->lwb_buf
;
1399 bp
= &zilc
->zc_next_blk
;
1401 zilc
= (zil_chain_t
*)(lwb
->lwb_buf
+ lwb
->lwb_sz
);
1402 bp
= &zilc
->zc_next_blk
;
1405 ASSERT(lwb
->lwb_nused
<= lwb
->lwb_sz
);
1408 * Allocate the next block and save its address in this block
1409 * before writing it in order to establish the log chain.
1410 * Note that if the allocation of nlwb synced before we wrote
1411 * the block that points at it (lwb), we'd leak it if we crashed.
1412 * Therefore, we don't do dmu_tx_commit() until zil_lwb_write_done().
1413 * We dirty the dataset to ensure that zil_sync() will be called
1414 * to clean up in the event of allocation failure or I/O failure.
1417 tx
= dmu_tx_create(zilog
->zl_os
);
1420 * Since we are not going to create any new dirty data, and we
1421 * can even help with clearing the existing dirty data, we
1422 * should not be subject to the dirty data based delays. We
1423 * use TXG_NOTHROTTLE to bypass the delay mechanism.
1425 VERIFY0(dmu_tx_assign(tx
, TXG_WAIT
| TXG_NOTHROTTLE
));
1427 dsl_dataset_dirty(dmu_objset_ds(zilog
->zl_os
), tx
);
1428 txg
= dmu_tx_get_txg(tx
);
1433 * Log blocks are pre-allocated. Here we select the size of the next
1434 * block, based on size used in the last block.
1435 * - first find the smallest bucket that will fit the block from a
1436 * limited set of block sizes. This is because it's faster to write
1437 * blocks allocated from the same metaslab as they are adjacent or
1439 * - next find the maximum from the new suggested size and an array of
1440 * previous sizes. This lessens a picket fence effect of wrongly
1441 * guesssing the size if we have a stream of say 2k, 64k, 2k, 64k
1444 * Note we only write what is used, but we can't just allocate
1445 * the maximum block size because we can exhaust the available
1448 zil_blksz
= zilog
->zl_cur_used
+ sizeof (zil_chain_t
);
1449 for (i
= 0; zil_blksz
> zil_block_buckets
[i
]; i
++)
1451 zil_blksz
= zil_block_buckets
[i
];
1452 if (zil_blksz
== UINT64_MAX
)
1453 zil_blksz
= SPA_OLD_MAXBLOCKSIZE
;
1454 zilog
->zl_prev_blks
[zilog
->zl_prev_rotor
] = zil_blksz
;
1455 for (i
= 0; i
< ZIL_PREV_BLKS
; i
++)
1456 zil_blksz
= MAX(zil_blksz
, zilog
->zl_prev_blks
[i
]);
1457 zilog
->zl_prev_rotor
= (zilog
->zl_prev_rotor
+ 1) & (ZIL_PREV_BLKS
- 1);
1461 /* pass the old blkptr in order to spread log blocks across devs */
1462 error
= zio_alloc_zil(spa
, zilog
->zl_os
, txg
, bp
, &lwb
->lwb_blk
,
1466 ASSERT3U(bp
->blk_birth
, ==, txg
);
1467 bp
->blk_cksum
= lwb
->lwb_blk
.blk_cksum
;
1468 bp
->blk_cksum
.zc_word
[ZIL_ZC_SEQ
]++;
1471 * Allocate a new log write block (lwb).
1473 nlwb
= zil_alloc_lwb(zilog
, bp
, slog
, txg
);
1476 if (BP_GET_CHECKSUM(&lwb
->lwb_blk
) == ZIO_CHECKSUM_ZILOG2
) {
1477 /* For Slim ZIL only write what is used. */
1478 wsz
= P2ROUNDUP_TYPED(lwb
->lwb_nused
, ZIL_MIN_BLKSZ
, uint64_t);
1479 ASSERT3U(wsz
, <=, lwb
->lwb_sz
);
1480 zio_shrink(lwb
->lwb_write_zio
, wsz
);
1487 zilc
->zc_nused
= lwb
->lwb_nused
;
1488 zilc
->zc_eck
.zec_cksum
= lwb
->lwb_blk
.blk_cksum
;
1491 * clear unused data for security
1493 bzero(lwb
->lwb_buf
+ lwb
->lwb_nused
, wsz
- lwb
->lwb_nused
);
1495 spa_config_enter(zilog
->zl_spa
, SCL_STATE
, lwb
, RW_READER
);
1497 zil_lwb_add_block(lwb
, &lwb
->lwb_blk
);
1498 lwb
->lwb_issued_timestamp
= gethrtime();
1499 lwb
->lwb_state
= LWB_STATE_ISSUED
;
1501 zio_nowait(lwb
->lwb_root_zio
);
1502 zio_nowait(lwb
->lwb_write_zio
);
1505 * If there was an allocation failure then nlwb will be null which
1506 * forces a txg_wait_synced().
1512 zil_lwb_commit(zilog_t
*zilog
, itx_t
*itx
, lwb_t
*lwb
)
1515 lr_write_t
*lrwb
, *lrw
;
1517 uint64_t dlen
, dnow
, lwb_sp
, reclen
, txg
;
1519 ASSERT(MUTEX_HELD(&zilog
->zl_issuer_lock
));
1520 ASSERT3P(lwb
, !=, NULL
);
1521 ASSERT3P(lwb
->lwb_buf
, !=, NULL
);
1523 zil_lwb_write_open(zilog
, lwb
);
1526 lrw
= (lr_write_t
*)lrc
;
1529 * A commit itx doesn't represent any on-disk state; instead
1530 * it's simply used as a place holder on the commit list, and
1531 * provides a mechanism for attaching a "commit waiter" onto the
1532 * correct lwb (such that the waiter can be signalled upon
1533 * completion of that lwb). Thus, we don't process this itx's
1534 * log record if it's a commit itx (these itx's don't have log
1535 * records), and instead link the itx's waiter onto the lwb's
1538 * For more details, see the comment above zil_commit().
1540 if (lrc
->lrc_txtype
== TX_COMMIT
) {
1541 mutex_enter(&zilog
->zl_lock
);
1542 zil_commit_waiter_link_lwb(itx
->itx_private
, lwb
);
1543 itx
->itx_private
= NULL
;
1544 mutex_exit(&zilog
->zl_lock
);
1548 if (lrc
->lrc_txtype
== TX_WRITE
&& itx
->itx_wr_state
== WR_NEED_COPY
) {
1549 dlen
= P2ROUNDUP_TYPED(
1550 lrw
->lr_length
, sizeof (uint64_t), uint64_t);
1554 reclen
= lrc
->lrc_reclen
;
1555 zilog
->zl_cur_used
+= (reclen
+ dlen
);
1558 ASSERT3U(zilog
->zl_cur_used
, <, UINT64_MAX
- (reclen
+ dlen
));
1562 * If this record won't fit in the current log block, start a new one.
1563 * For WR_NEED_COPY optimize layout for minimal number of chunks.
1565 lwb_sp
= lwb
->lwb_sz
- lwb
->lwb_nused
;
1566 if (reclen
> lwb_sp
|| (reclen
+ dlen
> lwb_sp
&&
1567 lwb_sp
< ZIL_MAX_WASTE_SPACE
&& (dlen
% ZIL_MAX_LOG_DATA
== 0 ||
1568 lwb_sp
< reclen
+ dlen
% ZIL_MAX_LOG_DATA
))) {
1569 lwb
= zil_lwb_write_issue(zilog
, lwb
);
1572 zil_lwb_write_open(zilog
, lwb
);
1573 ASSERT(LWB_EMPTY(lwb
));
1574 lwb_sp
= lwb
->lwb_sz
- lwb
->lwb_nused
;
1575 ASSERT3U(reclen
+ MIN(dlen
, sizeof (uint64_t)), <=, lwb_sp
);
1578 dnow
= MIN(dlen
, lwb_sp
- reclen
);
1579 lr_buf
= lwb
->lwb_buf
+ lwb
->lwb_nused
;
1580 bcopy(lrc
, lr_buf
, reclen
);
1581 lrcb
= (lr_t
*)lr_buf
; /* Like lrc, but inside lwb. */
1582 lrwb
= (lr_write_t
*)lrcb
; /* Like lrw, but inside lwb. */
1585 * If it's a write, fetch the data or get its blkptr as appropriate.
1587 if (lrc
->lrc_txtype
== TX_WRITE
) {
1588 if (txg
> spa_freeze_txg(zilog
->zl_spa
))
1589 txg_wait_synced(zilog
->zl_dmu_pool
, txg
);
1590 if (itx
->itx_wr_state
!= WR_COPIED
) {
1594 if (itx
->itx_wr_state
== WR_NEED_COPY
) {
1595 dbuf
= lr_buf
+ reclen
;
1596 lrcb
->lrc_reclen
+= dnow
;
1597 if (lrwb
->lr_length
> dnow
)
1598 lrwb
->lr_length
= dnow
;
1599 lrw
->lr_offset
+= dnow
;
1600 lrw
->lr_length
-= dnow
;
1602 ASSERT(itx
->itx_wr_state
== WR_INDIRECT
);
1607 * We pass in the "lwb_write_zio" rather than
1608 * "lwb_root_zio" so that the "lwb_write_zio"
1609 * becomes the parent of any zio's created by
1610 * the "zl_get_data" callback. The vdevs are
1611 * flushed after the "lwb_write_zio" completes,
1612 * so we want to make sure that completion
1613 * callback waits for these additional zio's,
1614 * such that the vdevs used by those zio's will
1615 * be included in the lwb's vdev tree, and those
1616 * vdevs will be properly flushed. If we passed
1617 * in "lwb_root_zio" here, then these additional
1618 * vdevs may not be flushed; e.g. if these zio's
1619 * completed after "lwb_write_zio" completed.
1621 error
= zilog
->zl_get_data(itx
->itx_private
,
1622 lrwb
, dbuf
, lwb
, lwb
->lwb_write_zio
);
1625 txg_wait_synced(zilog
->zl_dmu_pool
, txg
);
1629 ASSERT(error
== ENOENT
|| error
== EEXIST
||
1637 * We're actually making an entry, so update lrc_seq to be the
1638 * log record sequence number. Note that this is generally not
1639 * equal to the itx sequence number because not all transactions
1640 * are synchronous, and sometimes spa_sync() gets there first.
1642 lrcb
->lrc_seq
= ++zilog
->zl_lr_seq
;
1643 lwb
->lwb_nused
+= reclen
+ dnow
;
1645 zil_lwb_add_txg(lwb
, txg
);
1647 ASSERT3U(lwb
->lwb_nused
, <=, lwb
->lwb_sz
);
1648 ASSERT0(P2PHASE(lwb
->lwb_nused
, sizeof (uint64_t)));
1652 zilog
->zl_cur_used
+= reclen
;
1660 zil_itx_create(uint64_t txtype
, size_t lrsize
)
1664 lrsize
= P2ROUNDUP_TYPED(lrsize
, sizeof (uint64_t), size_t);
1666 itx
= kmem_alloc(offsetof(itx_t
, itx_lr
) + lrsize
, KM_SLEEP
);
1667 itx
->itx_lr
.lrc_txtype
= txtype
;
1668 itx
->itx_lr
.lrc_reclen
= lrsize
;
1669 itx
->itx_lr
.lrc_seq
= 0; /* defensive */
1670 itx
->itx_sync
= B_TRUE
; /* default is synchronous */
1676 zil_itx_destroy(itx_t
*itx
)
1678 kmem_free(itx
, offsetof(itx_t
, itx_lr
) + itx
->itx_lr
.lrc_reclen
);
1682 * Free up the sync and async itxs. The itxs_t has already been detached
1683 * so no locks are needed.
1686 zil_itxg_clean(itxs_t
*itxs
)
1692 itx_async_node_t
*ian
;
1694 list
= &itxs
->i_sync_list
;
1695 while ((itx
= list_head(list
)) != NULL
) {
1697 * In the general case, commit itxs will not be found
1698 * here, as they'll be committed to an lwb via
1699 * zil_lwb_commit(), and free'd in that function. Having
1700 * said that, it is still possible for commit itxs to be
1701 * found here, due to the following race:
1703 * - a thread calls zil_commit() which assigns the
1704 * commit itx to a per-txg i_sync_list
1705 * - zil_itxg_clean() is called (e.g. via spa_sync())
1706 * while the waiter is still on the i_sync_list
1708 * There's nothing to prevent syncing the txg while the
1709 * waiter is on the i_sync_list. This normally doesn't
1710 * happen because spa_sync() is slower than zil_commit(),
1711 * but if zil_commit() calls txg_wait_synced() (e.g.
1712 * because zil_create() or zil_commit_writer_stall() is
1713 * called) we will hit this case.
1715 if (itx
->itx_lr
.lrc_txtype
== TX_COMMIT
)
1716 zil_commit_waiter_skip(itx
->itx_private
);
1718 list_remove(list
, itx
);
1719 zil_itx_destroy(itx
);
1723 t
= &itxs
->i_async_tree
;
1724 while ((ian
= avl_destroy_nodes(t
, &cookie
)) != NULL
) {
1725 list
= &ian
->ia_list
;
1726 while ((itx
= list_head(list
)) != NULL
) {
1727 list_remove(list
, itx
);
1728 /* commit itxs should never be on the async lists. */
1729 ASSERT3U(itx
->itx_lr
.lrc_txtype
, !=, TX_COMMIT
);
1730 zil_itx_destroy(itx
);
1733 kmem_free(ian
, sizeof (itx_async_node_t
));
1737 kmem_free(itxs
, sizeof (itxs_t
));
1741 zil_aitx_compare(const void *x1
, const void *x2
)
1743 const uint64_t o1
= ((itx_async_node_t
*)x1
)->ia_foid
;
1744 const uint64_t o2
= ((itx_async_node_t
*)x2
)->ia_foid
;
1746 return (TREE_CMP(o1
, o2
));
1750 * Remove all async itx with the given oid.
1753 zil_remove_async(zilog_t
*zilog
, uint64_t oid
)
1756 itx_async_node_t
*ian
;
1763 list_create(&clean_list
, sizeof (itx_t
), offsetof(itx_t
, itx_node
));
1765 if (spa_freeze_txg(zilog
->zl_spa
) != UINT64_MAX
) /* ziltest support */
1768 otxg
= spa_last_synced_txg(zilog
->zl_spa
) + 1;
1770 for (txg
= otxg
; txg
< (otxg
+ TXG_CONCURRENT_STATES
); txg
++) {
1771 itxg_t
*itxg
= &zilog
->zl_itxg
[txg
& TXG_MASK
];
1773 mutex_enter(&itxg
->itxg_lock
);
1774 if (itxg
->itxg_txg
!= txg
) {
1775 mutex_exit(&itxg
->itxg_lock
);
1780 * Locate the object node and append its list.
1782 t
= &itxg
->itxg_itxs
->i_async_tree
;
1783 ian
= avl_find(t
, &oid
, &where
);
1785 list_move_tail(&clean_list
, &ian
->ia_list
);
1786 mutex_exit(&itxg
->itxg_lock
);
1788 while ((itx
= list_head(&clean_list
)) != NULL
) {
1789 list_remove(&clean_list
, itx
);
1790 /* commit itxs should never be on the async lists. */
1791 ASSERT3U(itx
->itx_lr
.lrc_txtype
, !=, TX_COMMIT
);
1792 zil_itx_destroy(itx
);
1794 list_destroy(&clean_list
);
1798 zil_itx_assign(zilog_t
*zilog
, itx_t
*itx
, dmu_tx_t
*tx
)
1802 itxs_t
*itxs
, *clean
= NULL
;
1805 * Ensure the data of a renamed file is committed before the rename.
1807 if ((itx
->itx_lr
.lrc_txtype
& ~TX_CI
) == TX_RENAME
)
1808 zil_async_to_sync(zilog
, itx
->itx_oid
);
1810 if (spa_freeze_txg(zilog
->zl_spa
) != UINT64_MAX
)
1813 txg
= dmu_tx_get_txg(tx
);
1815 itxg
= &zilog
->zl_itxg
[txg
& TXG_MASK
];
1816 mutex_enter(&itxg
->itxg_lock
);
1817 itxs
= itxg
->itxg_itxs
;
1818 if (itxg
->itxg_txg
!= txg
) {
1821 * The zil_clean callback hasn't got around to cleaning
1822 * this itxg. Save the itxs for release below.
1823 * This should be rare.
1825 zfs_dbgmsg("zil_itx_assign: missed itx cleanup for "
1826 "txg %llu", itxg
->itxg_txg
);
1827 clean
= itxg
->itxg_itxs
;
1829 itxg
->itxg_txg
= txg
;
1830 itxs
= itxg
->itxg_itxs
= kmem_zalloc(sizeof (itxs_t
), KM_SLEEP
);
1832 list_create(&itxs
->i_sync_list
, sizeof (itx_t
),
1833 offsetof(itx_t
, itx_node
));
1834 avl_create(&itxs
->i_async_tree
, zil_aitx_compare
,
1835 sizeof (itx_async_node_t
),
1836 offsetof(itx_async_node_t
, ia_node
));
1838 if (itx
->itx_sync
) {
1839 list_insert_tail(&itxs
->i_sync_list
, itx
);
1841 avl_tree_t
*t
= &itxs
->i_async_tree
;
1843 LR_FOID_GET_OBJ(((lr_ooo_t
*)&itx
->itx_lr
)->lr_foid
);
1844 itx_async_node_t
*ian
;
1847 ian
= avl_find(t
, &foid
, &where
);
1849 ian
= kmem_alloc(sizeof (itx_async_node_t
), KM_SLEEP
);
1850 list_create(&ian
->ia_list
, sizeof (itx_t
),
1851 offsetof(itx_t
, itx_node
));
1852 ian
->ia_foid
= foid
;
1853 avl_insert(t
, ian
, where
);
1855 list_insert_tail(&ian
->ia_list
, itx
);
1858 itx
->itx_lr
.lrc_txg
= dmu_tx_get_txg(tx
);
1861 * We don't want to dirty the ZIL using ZILTEST_TXG, because
1862 * zil_clean() will never be called using ZILTEST_TXG. Thus, we
1863 * need to be careful to always dirty the ZIL using the "real"
1864 * TXG (not itxg_txg) even when the SPA is frozen.
1866 zilog_dirty(zilog
, dmu_tx_get_txg(tx
));
1867 mutex_exit(&itxg
->itxg_lock
);
1869 /* Release the old itxs now we've dropped the lock */
1871 zil_itxg_clean(clean
);
1875 * If there are any in-memory intent log transactions which have now been
1876 * synced then start up a taskq to free them. We should only do this after we
1877 * have written out the uberblocks (i.e. txg has been comitted) so that
1878 * don't inadvertently clean out in-memory log records that would be required
1882 zil_clean(zilog_t
*zilog
, uint64_t synced_txg
)
1884 itxg_t
*itxg
= &zilog
->zl_itxg
[synced_txg
& TXG_MASK
];
1887 ASSERT3U(synced_txg
, <, ZILTEST_TXG
);
1889 mutex_enter(&itxg
->itxg_lock
);
1890 if (itxg
->itxg_itxs
== NULL
|| itxg
->itxg_txg
== ZILTEST_TXG
) {
1891 mutex_exit(&itxg
->itxg_lock
);
1894 ASSERT3U(itxg
->itxg_txg
, <=, synced_txg
);
1895 ASSERT3U(itxg
->itxg_txg
, !=, 0);
1896 clean_me
= itxg
->itxg_itxs
;
1897 itxg
->itxg_itxs
= NULL
;
1899 mutex_exit(&itxg
->itxg_lock
);
1901 * Preferably start a task queue to free up the old itxs but
1902 * if taskq_dispatch can't allocate resources to do that then
1903 * free it in-line. This should be rare. Note, using TQ_SLEEP
1904 * created a bad performance problem.
1906 ASSERT3P(zilog
->zl_dmu_pool
, !=, NULL
);
1907 ASSERT3P(zilog
->zl_dmu_pool
->dp_zil_clean_taskq
, !=, NULL
);
1908 if (taskq_dispatch(zilog
->zl_dmu_pool
->dp_zil_clean_taskq
,
1909 (void (*)(void *))zil_itxg_clean
, clean_me
, TQ_NOSLEEP
) ==
1911 zil_itxg_clean(clean_me
);
1915 * This function will traverse the queue of itxs that need to be
1916 * committed, and move them onto the ZIL's zl_itx_commit_list.
1919 zil_get_commit_list(zilog_t
*zilog
)
1922 list_t
*commit_list
= &zilog
->zl_itx_commit_list
;
1924 ASSERT(MUTEX_HELD(&zilog
->zl_issuer_lock
));
1926 if (spa_freeze_txg(zilog
->zl_spa
) != UINT64_MAX
) /* ziltest support */
1929 otxg
= spa_last_synced_txg(zilog
->zl_spa
) + 1;
1932 * This is inherently racy, since there is nothing to prevent
1933 * the last synced txg from changing. That's okay since we'll
1934 * only commit things in the future.
1936 for (txg
= otxg
; txg
< (otxg
+ TXG_CONCURRENT_STATES
); txg
++) {
1937 itxg_t
*itxg
= &zilog
->zl_itxg
[txg
& TXG_MASK
];
1939 mutex_enter(&itxg
->itxg_lock
);
1940 if (itxg
->itxg_txg
!= txg
) {
1941 mutex_exit(&itxg
->itxg_lock
);
1946 * If we're adding itx records to the zl_itx_commit_list,
1947 * then the zil better be dirty in this "txg". We can assert
1948 * that here since we're holding the itxg_lock which will
1949 * prevent spa_sync from cleaning it. Once we add the itxs
1950 * to the zl_itx_commit_list we must commit it to disk even
1951 * if it's unnecessary (i.e. the txg was synced).
1953 ASSERT(zilog_is_dirty_in_txg(zilog
, txg
) ||
1954 spa_freeze_txg(zilog
->zl_spa
) != UINT64_MAX
);
1955 list_move_tail(commit_list
, &itxg
->itxg_itxs
->i_sync_list
);
1957 mutex_exit(&itxg
->itxg_lock
);
1962 * Move the async itxs for a specified object to commit into sync lists.
1965 zil_async_to_sync(zilog_t
*zilog
, uint64_t foid
)
1968 itx_async_node_t
*ian
;
1972 if (spa_freeze_txg(zilog
->zl_spa
) != UINT64_MAX
) /* ziltest support */
1975 otxg
= spa_last_synced_txg(zilog
->zl_spa
) + 1;
1978 * This is inherently racy, since there is nothing to prevent
1979 * the last synced txg from changing.
1981 for (txg
= otxg
; txg
< (otxg
+ TXG_CONCURRENT_STATES
); txg
++) {
1982 itxg_t
*itxg
= &zilog
->zl_itxg
[txg
& TXG_MASK
];
1984 mutex_enter(&itxg
->itxg_lock
);
1985 if (itxg
->itxg_txg
!= txg
) {
1986 mutex_exit(&itxg
->itxg_lock
);
1991 * If a foid is specified then find that node and append its
1992 * list. Otherwise walk the tree appending all the lists
1993 * to the sync list. We add to the end rather than the
1994 * beginning to ensure the create has happened.
1996 t
= &itxg
->itxg_itxs
->i_async_tree
;
1998 ian
= avl_find(t
, &foid
, &where
);
2000 list_move_tail(&itxg
->itxg_itxs
->i_sync_list
,
2004 void *cookie
= NULL
;
2006 while ((ian
= avl_destroy_nodes(t
, &cookie
)) != NULL
) {
2007 list_move_tail(&itxg
->itxg_itxs
->i_sync_list
,
2009 list_destroy(&ian
->ia_list
);
2010 kmem_free(ian
, sizeof (itx_async_node_t
));
2013 mutex_exit(&itxg
->itxg_lock
);
2018 * This function will prune commit itxs that are at the head of the
2019 * commit list (it won't prune past the first non-commit itx), and
2020 * either: a) attach them to the last lwb that's still pending
2021 * completion, or b) skip them altogether.
2023 * This is used as a performance optimization to prevent commit itxs
2024 * from generating new lwbs when it's unnecessary to do so.
2027 zil_prune_commit_list(zilog_t
*zilog
)
2031 ASSERT(MUTEX_HELD(&zilog
->zl_issuer_lock
));
2033 while (itx
= list_head(&zilog
->zl_itx_commit_list
)) {
2034 lr_t
*lrc
= &itx
->itx_lr
;
2035 if (lrc
->lrc_txtype
!= TX_COMMIT
)
2038 mutex_enter(&zilog
->zl_lock
);
2040 lwb_t
*last_lwb
= zilog
->zl_last_lwb_opened
;
2041 if (last_lwb
== NULL
||
2042 last_lwb
->lwb_state
== LWB_STATE_FLUSH_DONE
) {
2044 * All of the itxs this waiter was waiting on
2045 * must have already completed (or there were
2046 * never any itx's for it to wait on), so it's
2047 * safe to skip this waiter and mark it done.
2049 zil_commit_waiter_skip(itx
->itx_private
);
2051 zil_commit_waiter_link_lwb(itx
->itx_private
, last_lwb
);
2052 itx
->itx_private
= NULL
;
2055 mutex_exit(&zilog
->zl_lock
);
2057 list_remove(&zilog
->zl_itx_commit_list
, itx
);
2058 zil_itx_destroy(itx
);
2061 IMPLY(itx
!= NULL
, itx
->itx_lr
.lrc_txtype
!= TX_COMMIT
);
2065 zil_commit_writer_stall(zilog_t
*zilog
)
2068 * When zio_alloc_zil() fails to allocate the next lwb block on
2069 * disk, we must call txg_wait_synced() to ensure all of the
2070 * lwbs in the zilog's zl_lwb_list are synced and then freed (in
2071 * zil_sync()), such that any subsequent ZIL writer (i.e. a call
2072 * to zil_process_commit_list()) will have to call zil_create(),
2073 * and start a new ZIL chain.
2075 * Since zil_alloc_zil() failed, the lwb that was previously
2076 * issued does not have a pointer to the "next" lwb on disk.
2077 * Thus, if another ZIL writer thread was to allocate the "next"
2078 * on-disk lwb, that block could be leaked in the event of a
2079 * crash (because the previous lwb on-disk would not point to
2082 * We must hold the zilog's zl_issuer_lock while we do this, to
2083 * ensure no new threads enter zil_process_commit_list() until
2084 * all lwb's in the zl_lwb_list have been synced and freed
2085 * (which is achieved via the txg_wait_synced() call).
2087 ASSERT(MUTEX_HELD(&zilog
->zl_issuer_lock
));
2088 txg_wait_synced(zilog
->zl_dmu_pool
, 0);
2089 ASSERT3P(list_tail(&zilog
->zl_lwb_list
), ==, NULL
);
2093 * This function will traverse the commit list, creating new lwbs as
2094 * needed, and committing the itxs from the commit list to these newly
2095 * created lwbs. Additionally, as a new lwb is created, the previous
2096 * lwb will be issued to the zio layer to be written to disk.
2099 zil_process_commit_list(zilog_t
*zilog
)
2101 spa_t
*spa
= zilog
->zl_spa
;
2102 list_t nolwb_waiters
;
2106 ASSERT(MUTEX_HELD(&zilog
->zl_issuer_lock
));
2109 * Return if there's nothing to commit before we dirty the fs by
2110 * calling zil_create().
2112 if (list_head(&zilog
->zl_itx_commit_list
) == NULL
)
2115 list_create(&nolwb_waiters
, sizeof (zil_commit_waiter_t
),
2116 offsetof(zil_commit_waiter_t
, zcw_node
));
2118 lwb
= list_tail(&zilog
->zl_lwb_list
);
2120 lwb
= zil_create(zilog
);
2122 ASSERT3S(lwb
->lwb_state
, !=, LWB_STATE_ISSUED
);
2123 ASSERT3S(lwb
->lwb_state
, !=, LWB_STATE_WRITE_DONE
);
2124 ASSERT3S(lwb
->lwb_state
, !=, LWB_STATE_FLUSH_DONE
);
2127 while (itx
= list_head(&zilog
->zl_itx_commit_list
)) {
2128 lr_t
*lrc
= &itx
->itx_lr
;
2129 uint64_t txg
= lrc
->lrc_txg
;
2131 ASSERT3U(txg
, !=, 0);
2133 if (lrc
->lrc_txtype
== TX_COMMIT
) {
2134 DTRACE_PROBE2(zil__process__commit__itx
,
2135 zilog_t
*, zilog
, itx_t
*, itx
);
2137 DTRACE_PROBE2(zil__process__normal__itx
,
2138 zilog_t
*, zilog
, itx_t
*, itx
);
2141 boolean_t synced
= txg
<= spa_last_synced_txg(spa
);
2142 boolean_t frozen
= txg
> spa_freeze_txg(spa
);
2145 * If the txg of this itx has already been synced out, then
2146 * we don't need to commit this itx to an lwb. This is
2147 * because the data of this itx will have already been
2148 * written to the main pool. This is inherently racy, and
2149 * it's still ok to commit an itx whose txg has already
2150 * been synced; this will result in a write that's
2151 * unnecessary, but will do no harm.
2153 * With that said, we always want to commit TX_COMMIT itxs
2154 * to an lwb, regardless of whether or not that itx's txg
2155 * has been synced out. We do this to ensure any OPENED lwb
2156 * will always have at least one zil_commit_waiter_t linked
2159 * As a counter-example, if we skipped TX_COMMIT itx's
2160 * whose txg had already been synced, the following
2161 * situation could occur if we happened to be racing with
2164 * 1. we commit a non-TX_COMMIT itx to an lwb, where the
2165 * itx's txg is 10 and the last synced txg is 9.
2166 * 2. spa_sync finishes syncing out txg 10.
2167 * 3. we move to the next itx in the list, it's a TX_COMMIT
2168 * whose txg is 10, so we skip it rather than committing
2169 * it to the lwb used in (1).
2171 * If the itx that is skipped in (3) is the last TX_COMMIT
2172 * itx in the commit list, than it's possible for the lwb
2173 * used in (1) to remain in the OPENED state indefinitely.
2175 * To prevent the above scenario from occuring, ensuring
2176 * that once an lwb is OPENED it will transition to ISSUED
2177 * and eventually DONE, we always commit TX_COMMIT itx's to
2178 * an lwb here, even if that itx's txg has already been
2181 * Finally, if the pool is frozen, we _always_ commit the
2182 * itx. The point of freezing the pool is to prevent data
2183 * from being written to the main pool via spa_sync, and
2184 * instead rely solely on the ZIL to persistently store the
2185 * data; i.e. when the pool is frozen, the last synced txg
2186 * value can't be trusted.
2188 if (frozen
|| !synced
|| lrc
->lrc_txtype
== TX_COMMIT
) {
2190 lwb
= zil_lwb_commit(zilog
, itx
, lwb
);
2191 } else if (lrc
->lrc_txtype
== TX_COMMIT
) {
2192 ASSERT3P(lwb
, ==, NULL
);
2193 zil_commit_waiter_link_nolwb(
2194 itx
->itx_private
, &nolwb_waiters
);
2198 list_remove(&zilog
->zl_itx_commit_list
, itx
);
2199 zil_itx_destroy(itx
);
2204 * This indicates zio_alloc_zil() failed to allocate the
2205 * "next" lwb on-disk. When this happens, we must stall
2206 * the ZIL write pipeline; see the comment within
2207 * zil_commit_writer_stall() for more details.
2209 zil_commit_writer_stall(zilog
);
2212 * Additionally, we have to signal and mark the "nolwb"
2213 * waiters as "done" here, since without an lwb, we
2214 * can't do this via zil_lwb_flush_vdevs_done() like
2217 zil_commit_waiter_t
*zcw
;
2218 while (zcw
= list_head(&nolwb_waiters
)) {
2219 zil_commit_waiter_skip(zcw
);
2220 list_remove(&nolwb_waiters
, zcw
);
2223 ASSERT(list_is_empty(&nolwb_waiters
));
2224 ASSERT3P(lwb
, !=, NULL
);
2225 ASSERT3S(lwb
->lwb_state
, !=, LWB_STATE_ISSUED
);
2226 ASSERT3S(lwb
->lwb_state
, !=, LWB_STATE_WRITE_DONE
);
2227 ASSERT3S(lwb
->lwb_state
, !=, LWB_STATE_FLUSH_DONE
);
2230 * At this point, the ZIL block pointed at by the "lwb"
2231 * variable is in one of the following states: "closed"
2234 * If its "closed", then no itxs have been committed to
2235 * it, so there's no point in issuing its zio (i.e.
2238 * If its "open" state, then it contains one or more
2239 * itxs that eventually need to be committed to stable
2240 * storage. In this case we intentionally do not issue
2241 * the lwb's zio to disk yet, and instead rely on one of
2242 * the following two mechanisms for issuing the zio:
2244 * 1. Ideally, there will be more ZIL activity occuring
2245 * on the system, such that this function will be
2246 * immediately called again (not necessarily by the same
2247 * thread) and this lwb's zio will be issued via
2248 * zil_lwb_commit(). This way, the lwb is guaranteed to
2249 * be "full" when it is issued to disk, and we'll make
2250 * use of the lwb's size the best we can.
2252 * 2. If there isn't sufficient ZIL activity occuring on
2253 * the system, such that this lwb's zio isn't issued via
2254 * zil_lwb_commit(), zil_commit_waiter() will issue the
2255 * lwb's zio. If this occurs, the lwb is not guaranteed
2256 * to be "full" by the time its zio is issued, and means
2257 * the size of the lwb was "too large" given the amount
2258 * of ZIL activity occuring on the system at that time.
2260 * We do this for a couple of reasons:
2262 * 1. To try and reduce the number of IOPs needed to
2263 * write the same number of itxs. If an lwb has space
2264 * available in it's buffer for more itxs, and more itxs
2265 * will be committed relatively soon (relative to the
2266 * latency of performing a write), then it's beneficial
2267 * to wait for these "next" itxs. This way, more itxs
2268 * can be committed to stable storage with fewer writes.
2270 * 2. To try and use the largest lwb block size that the
2271 * incoming rate of itxs can support. Again, this is to
2272 * try and pack as many itxs into as few lwbs as
2273 * possible, without significantly impacting the latency
2274 * of each individual itx.
2280 * This function is responsible for ensuring the passed in commit waiter
2281 * (and associated commit itx) is committed to an lwb. If the waiter is
2282 * not already committed to an lwb, all itxs in the zilog's queue of
2283 * itxs will be processed. The assumption is the passed in waiter's
2284 * commit itx will found in the queue just like the other non-commit
2285 * itxs, such that when the entire queue is processed, the waiter will
2286 * have been commited to an lwb.
2288 * The lwb associated with the passed in waiter is not guaranteed to
2289 * have been issued by the time this function completes. If the lwb is
2290 * not issued, we rely on future calls to zil_commit_writer() to issue
2291 * the lwb, or the timeout mechanism found in zil_commit_waiter().
2294 zil_commit_writer(zilog_t
*zilog
, zil_commit_waiter_t
*zcw
)
2296 ASSERT(!MUTEX_HELD(&zilog
->zl_lock
));
2297 ASSERT(spa_writeable(zilog
->zl_spa
));
2299 mutex_enter(&zilog
->zl_issuer_lock
);
2301 if (zcw
->zcw_lwb
!= NULL
|| zcw
->zcw_done
) {
2303 * It's possible that, while we were waiting to acquire
2304 * the "zl_issuer_lock", another thread committed this
2305 * waiter to an lwb. If that occurs, we bail out early,
2306 * without processing any of the zilog's queue of itxs.
2308 * On certain workloads and system configurations, the
2309 * "zl_issuer_lock" can become highly contended. In an
2310 * attempt to reduce this contention, we immediately drop
2311 * the lock if the waiter has already been processed.
2313 * We've measured this optimization to reduce CPU spent
2314 * contending on this lock by up to 5%, using a system
2315 * with 32 CPUs, low latency storage (~50 usec writes),
2316 * and 1024 threads performing sync writes.
2321 zil_get_commit_list(zilog
);
2322 zil_prune_commit_list(zilog
);
2323 zil_process_commit_list(zilog
);
2326 mutex_exit(&zilog
->zl_issuer_lock
);
2330 zil_commit_waiter_timeout(zilog_t
*zilog
, zil_commit_waiter_t
*zcw
)
2332 ASSERT(!MUTEX_HELD(&zilog
->zl_issuer_lock
));
2333 ASSERT(MUTEX_HELD(&zcw
->zcw_lock
));
2334 ASSERT3B(zcw
->zcw_done
, ==, B_FALSE
);
2336 lwb_t
*lwb
= zcw
->zcw_lwb
;
2337 ASSERT3P(lwb
, !=, NULL
);
2338 ASSERT3S(lwb
->lwb_state
, !=, LWB_STATE_CLOSED
);
2341 * If the lwb has already been issued by another thread, we can
2342 * immediately return since there's no work to be done (the
2343 * point of this function is to issue the lwb). Additionally, we
2344 * do this prior to acquiring the zl_issuer_lock, to avoid
2345 * acquiring it when it's not necessary to do so.
2347 if (lwb
->lwb_state
== LWB_STATE_ISSUED
||
2348 lwb
->lwb_state
== LWB_STATE_WRITE_DONE
||
2349 lwb
->lwb_state
== LWB_STATE_FLUSH_DONE
)
2353 * In order to call zil_lwb_write_issue() we must hold the
2354 * zilog's "zl_issuer_lock". We can't simply acquire that lock,
2355 * since we're already holding the commit waiter's "zcw_lock",
2356 * and those two locks are aquired in the opposite order
2359 mutex_exit(&zcw
->zcw_lock
);
2360 mutex_enter(&zilog
->zl_issuer_lock
);
2361 mutex_enter(&zcw
->zcw_lock
);
2364 * Since we just dropped and re-acquired the commit waiter's
2365 * lock, we have to re-check to see if the waiter was marked
2366 * "done" during that process. If the waiter was marked "done",
2367 * the "lwb" pointer is no longer valid (it can be free'd after
2368 * the waiter is marked "done"), so without this check we could
2369 * wind up with a use-after-free error below.
2374 ASSERT3P(lwb
, ==, zcw
->zcw_lwb
);
2377 * We've already checked this above, but since we hadn't acquired
2378 * the zilog's zl_issuer_lock, we have to perform this check a
2379 * second time while holding the lock.
2381 * We don't need to hold the zl_lock since the lwb cannot transition
2382 * from OPENED to ISSUED while we hold the zl_issuer_lock. The lwb
2383 * _can_ transition from ISSUED to DONE, but it's OK to race with
2384 * that transition since we treat the lwb the same, whether it's in
2385 * the ISSUED or DONE states.
2387 * The important thing, is we treat the lwb differently depending on
2388 * if it's ISSUED or OPENED, and block any other threads that might
2389 * attempt to issue this lwb. For that reason we hold the
2390 * zl_issuer_lock when checking the lwb_state; we must not call
2391 * zil_lwb_write_issue() if the lwb had already been issued.
2393 * See the comment above the lwb_state_t structure definition for
2394 * more details on the lwb states, and locking requirements.
2396 if (lwb
->lwb_state
== LWB_STATE_ISSUED
||
2397 lwb
->lwb_state
== LWB_STATE_WRITE_DONE
||
2398 lwb
->lwb_state
== LWB_STATE_FLUSH_DONE
)
2401 ASSERT3S(lwb
->lwb_state
, ==, LWB_STATE_OPENED
);
2404 * As described in the comments above zil_commit_waiter() and
2405 * zil_process_commit_list(), we need to issue this lwb's zio
2406 * since we've reached the commit waiter's timeout and it still
2407 * hasn't been issued.
2409 lwb_t
*nlwb
= zil_lwb_write_issue(zilog
, lwb
);
2411 IMPLY(nlwb
!= NULL
, lwb
->lwb_state
!= LWB_STATE_OPENED
);
2414 * Since the lwb's zio hadn't been issued by the time this thread
2415 * reached its timeout, we reset the zilog's "zl_cur_used" field
2416 * to influence the zil block size selection algorithm.
2418 * By having to issue the lwb's zio here, it means the size of the
2419 * lwb was too large, given the incoming throughput of itxs. By
2420 * setting "zl_cur_used" to zero, we communicate this fact to the
2421 * block size selection algorithm, so it can take this informaiton
2422 * into account, and potentially select a smaller size for the
2423 * next lwb block that is allocated.
2425 zilog
->zl_cur_used
= 0;
2429 * When zil_lwb_write_issue() returns NULL, this
2430 * indicates zio_alloc_zil() failed to allocate the
2431 * "next" lwb on-disk. When this occurs, the ZIL write
2432 * pipeline must be stalled; see the comment within the
2433 * zil_commit_writer_stall() function for more details.
2435 * We must drop the commit waiter's lock prior to
2436 * calling zil_commit_writer_stall() or else we can wind
2437 * up with the following deadlock:
2439 * - This thread is waiting for the txg to sync while
2440 * holding the waiter's lock; txg_wait_synced() is
2441 * used within txg_commit_writer_stall().
2443 * - The txg can't sync because it is waiting for this
2444 * lwb's zio callback to call dmu_tx_commit().
2446 * - The lwb's zio callback can't call dmu_tx_commit()
2447 * because it's blocked trying to acquire the waiter's
2448 * lock, which occurs prior to calling dmu_tx_commit()
2450 mutex_exit(&zcw
->zcw_lock
);
2451 zil_commit_writer_stall(zilog
);
2452 mutex_enter(&zcw
->zcw_lock
);
2456 mutex_exit(&zilog
->zl_issuer_lock
);
2457 ASSERT(MUTEX_HELD(&zcw
->zcw_lock
));
2461 * This function is responsible for performing the following two tasks:
2463 * 1. its primary responsibility is to block until the given "commit
2464 * waiter" is considered "done".
2466 * 2. its secondary responsibility is to issue the zio for the lwb that
2467 * the given "commit waiter" is waiting on, if this function has
2468 * waited "long enough" and the lwb is still in the "open" state.
2470 * Given a sufficient amount of itxs being generated and written using
2471 * the ZIL, the lwb's zio will be issued via the zil_lwb_commit()
2472 * function. If this does not occur, this secondary responsibility will
2473 * ensure the lwb is issued even if there is not other synchronous
2474 * activity on the system.
2476 * For more details, see zil_process_commit_list(); more specifically,
2477 * the comment at the bottom of that function.
2480 zil_commit_waiter(zilog_t
*zilog
, zil_commit_waiter_t
*zcw
)
2482 ASSERT(!MUTEX_HELD(&zilog
->zl_lock
));
2483 ASSERT(!MUTEX_HELD(&zilog
->zl_issuer_lock
));
2484 ASSERT(spa_writeable(zilog
->zl_spa
));
2486 mutex_enter(&zcw
->zcw_lock
);
2489 * The timeout is scaled based on the lwb latency to avoid
2490 * significantly impacting the latency of each individual itx.
2491 * For more details, see the comment at the bottom of the
2492 * zil_process_commit_list() function.
2494 int pct
= MAX(zfs_commit_timeout_pct
, 1);
2495 hrtime_t sleep
= (zilog
->zl_last_lwb_latency
* pct
) / 100;
2496 hrtime_t wakeup
= gethrtime() + sleep
;
2497 boolean_t timedout
= B_FALSE
;
2499 while (!zcw
->zcw_done
) {
2500 ASSERT(MUTEX_HELD(&zcw
->zcw_lock
));
2502 lwb_t
*lwb
= zcw
->zcw_lwb
;
2505 * Usually, the waiter will have a non-NULL lwb field here,
2506 * but it's possible for it to be NULL as a result of
2507 * zil_commit() racing with spa_sync().
2509 * When zil_clean() is called, it's possible for the itxg
2510 * list (which may be cleaned via a taskq) to contain
2511 * commit itxs. When this occurs, the commit waiters linked
2512 * off of these commit itxs will not be committed to an
2513 * lwb. Additionally, these commit waiters will not be
2514 * marked done until zil_commit_waiter_skip() is called via
2517 * Thus, it's possible for this commit waiter (i.e. the
2518 * "zcw" variable) to be found in this "in between" state;
2519 * where it's "zcw_lwb" field is NULL, and it hasn't yet
2520 * been skipped, so it's "zcw_done" field is still B_FALSE.
2522 IMPLY(lwb
!= NULL
, lwb
->lwb_state
!= LWB_STATE_CLOSED
);
2524 if (lwb
!= NULL
&& lwb
->lwb_state
== LWB_STATE_OPENED
) {
2525 ASSERT3B(timedout
, ==, B_FALSE
);
2528 * If the lwb hasn't been issued yet, then we
2529 * need to wait with a timeout, in case this
2530 * function needs to issue the lwb after the
2531 * timeout is reached; responsibility (2) from
2532 * the comment above this function.
2534 clock_t timeleft
= cv_timedwait_hires(&zcw
->zcw_cv
,
2535 &zcw
->zcw_lock
, wakeup
, USEC2NSEC(1),
2536 CALLOUT_FLAG_ABSOLUTE
);
2538 if (timeleft
>= 0 || zcw
->zcw_done
)
2542 zil_commit_waiter_timeout(zilog
, zcw
);
2544 if (!zcw
->zcw_done
) {
2546 * If the commit waiter has already been
2547 * marked "done", it's possible for the
2548 * waiter's lwb structure to have already
2549 * been freed. Thus, we can only reliably
2550 * make these assertions if the waiter
2553 ASSERT3P(lwb
, ==, zcw
->zcw_lwb
);
2554 ASSERT3S(lwb
->lwb_state
, !=, LWB_STATE_OPENED
);
2558 * If the lwb isn't open, then it must have already
2559 * been issued. In that case, there's no need to
2560 * use a timeout when waiting for the lwb to
2563 * Additionally, if the lwb is NULL, the waiter
2564 * will soon be signalled and marked done via
2565 * zil_clean() and zil_itxg_clean(), so no timeout
2570 lwb
->lwb_state
== LWB_STATE_ISSUED
||
2571 lwb
->lwb_state
== LWB_STATE_WRITE_DONE
||
2572 lwb
->lwb_state
== LWB_STATE_FLUSH_DONE
);
2573 cv_wait(&zcw
->zcw_cv
, &zcw
->zcw_lock
);
2577 mutex_exit(&zcw
->zcw_lock
);
2580 static zil_commit_waiter_t
*
2581 zil_alloc_commit_waiter()
2583 zil_commit_waiter_t
*zcw
= kmem_cache_alloc(zil_zcw_cache
, KM_SLEEP
);
2585 cv_init(&zcw
->zcw_cv
, NULL
, CV_DEFAULT
, NULL
);
2586 mutex_init(&zcw
->zcw_lock
, NULL
, MUTEX_DEFAULT
, NULL
);
2587 list_link_init(&zcw
->zcw_node
);
2588 zcw
->zcw_lwb
= NULL
;
2589 zcw
->zcw_done
= B_FALSE
;
2590 zcw
->zcw_zio_error
= 0;
2596 zil_free_commit_waiter(zil_commit_waiter_t
*zcw
)
2598 ASSERT(!list_link_active(&zcw
->zcw_node
));
2599 ASSERT3P(zcw
->zcw_lwb
, ==, NULL
);
2600 ASSERT3B(zcw
->zcw_done
, ==, B_TRUE
);
2601 mutex_destroy(&zcw
->zcw_lock
);
2602 cv_destroy(&zcw
->zcw_cv
);
2603 kmem_cache_free(zil_zcw_cache
, zcw
);
2607 * This function is used to create a TX_COMMIT itx and assign it. This
2608 * way, it will be linked into the ZIL's list of synchronous itxs, and
2609 * then later committed to an lwb (or skipped) when
2610 * zil_process_commit_list() is called.
2613 zil_commit_itx_assign(zilog_t
*zilog
, zil_commit_waiter_t
*zcw
)
2615 dmu_tx_t
*tx
= dmu_tx_create(zilog
->zl_os
);
2616 VERIFY0(dmu_tx_assign(tx
, TXG_WAIT
));
2618 itx_t
*itx
= zil_itx_create(TX_COMMIT
, sizeof (lr_t
));
2619 itx
->itx_sync
= B_TRUE
;
2620 itx
->itx_private
= zcw
;
2622 zil_itx_assign(zilog
, itx
, tx
);
2628 * Commit ZFS Intent Log transactions (itxs) to stable storage.
2630 * When writing ZIL transactions to the on-disk representation of the
2631 * ZIL, the itxs are committed to a Log Write Block (lwb). Multiple
2632 * itxs can be committed to a single lwb. Once a lwb is written and
2633 * committed to stable storage (i.e. the lwb is written, and vdevs have
2634 * been flushed), each itx that was committed to that lwb is also
2635 * considered to be committed to stable storage.
2637 * When an itx is committed to an lwb, the log record (lr_t) contained
2638 * by the itx is copied into the lwb's zio buffer, and once this buffer
2639 * is written to disk, it becomes an on-disk ZIL block.
2641 * As itxs are generated, they're inserted into the ZIL's queue of
2642 * uncommitted itxs. The semantics of zil_commit() are such that it will
2643 * block until all itxs that were in the queue when it was called, are
2644 * committed to stable storage.
2646 * If "foid" is zero, this means all "synchronous" and "asynchronous"
2647 * itxs, for all objects in the dataset, will be committed to stable
2648 * storage prior to zil_commit() returning. If "foid" is non-zero, all
2649 * "synchronous" itxs for all objects, but only "asynchronous" itxs
2650 * that correspond to the foid passed in, will be committed to stable
2651 * storage prior to zil_commit() returning.
2653 * Generally speaking, when zil_commit() is called, the consumer doesn't
2654 * actually care about _all_ of the uncommitted itxs. Instead, they're
2655 * simply trying to waiting for a specific itx to be committed to disk,
2656 * but the interface(s) for interacting with the ZIL don't allow such
2657 * fine-grained communication. A better interface would allow a consumer
2658 * to create and assign an itx, and then pass a reference to this itx to
2659 * zil_commit(); such that zil_commit() would return as soon as that
2660 * specific itx was committed to disk (instead of waiting for _all_
2661 * itxs to be committed).
2663 * When a thread calls zil_commit() a special "commit itx" will be
2664 * generated, along with a corresponding "waiter" for this commit itx.
2665 * zil_commit() will wait on this waiter's CV, such that when the waiter
2666 * is marked done, and signalled, zil_commit() will return.
2668 * This commit itx is inserted into the queue of uncommitted itxs. This
2669 * provides an easy mechanism for determining which itxs were in the
2670 * queue prior to zil_commit() having been called, and which itxs were
2671 * added after zil_commit() was called.
2673 * The commit it is special; it doesn't have any on-disk representation.
2674 * When a commit itx is "committed" to an lwb, the waiter associated
2675 * with it is linked onto the lwb's list of waiters. Then, when that lwb
2676 * completes, each waiter on the lwb's list is marked done and signalled
2677 * -- allowing the thread waiting on the waiter to return from zil_commit().
2679 * It's important to point out a few critical factors that allow us
2680 * to make use of the commit itxs, commit waiters, per-lwb lists of
2681 * commit waiters, and zio completion callbacks like we're doing:
2683 * 1. The list of waiters for each lwb is traversed, and each commit
2684 * waiter is marked "done" and signalled, in the zio completion
2685 * callback of the lwb's zio[*].
2687 * * Actually, the waiters are signalled in the zio completion
2688 * callback of the root zio for the DKIOCFLUSHWRITECACHE commands
2689 * that are sent to the vdevs upon completion of the lwb zio.
2691 * 2. When the itxs are inserted into the ZIL's queue of uncommitted
2692 * itxs, the order in which they are inserted is preserved[*]; as
2693 * itxs are added to the queue, they are added to the tail of
2694 * in-memory linked lists.
2696 * When committing the itxs to lwbs (to be written to disk), they
2697 * are committed in the same order in which the itxs were added to
2698 * the uncommitted queue's linked list(s); i.e. the linked list of
2699 * itxs to commit is traversed from head to tail, and each itx is
2700 * committed to an lwb in that order.
2704 * - the order of "sync" itxs is preserved w.r.t. other
2705 * "sync" itxs, regardless of the corresponding objects.
2706 * - the order of "async" itxs is preserved w.r.t. other
2707 * "async" itxs corresponding to the same object.
2708 * - the order of "async" itxs is *not* preserved w.r.t. other
2709 * "async" itxs corresponding to different objects.
2710 * - the order of "sync" itxs w.r.t. "async" itxs (or vice
2711 * versa) is *not* preserved, even for itxs that correspond
2712 * to the same object.
2714 * For more details, see: zil_itx_assign(), zil_async_to_sync(),
2715 * zil_get_commit_list(), and zil_process_commit_list().
2717 * 3. The lwbs represent a linked list of blocks on disk. Thus, any
2718 * lwb cannot be considered committed to stable storage, until its
2719 * "previous" lwb is also committed to stable storage. This fact,
2720 * coupled with the fact described above, means that itxs are
2721 * committed in (roughly) the order in which they were generated.
2722 * This is essential because itxs are dependent on prior itxs.
2723 * Thus, we *must not* deem an itx as being committed to stable
2724 * storage, until *all* prior itxs have also been committed to
2727 * To enforce this ordering of lwb zio's, while still leveraging as
2728 * much of the underlying storage performance as possible, we rely
2729 * on two fundamental concepts:
2731 * 1. The creation and issuance of lwb zio's is protected by
2732 * the zilog's "zl_issuer_lock", which ensures only a single
2733 * thread is creating and/or issuing lwb's at a time
2734 * 2. The "previous" lwb is a child of the "current" lwb
2735 * (leveraging the zio parent-child depenency graph)
2737 * By relying on this parent-child zio relationship, we can have
2738 * many lwb zio's concurrently issued to the underlying storage,
2739 * but the order in which they complete will be the same order in
2740 * which they were created.
2743 zil_commit(zilog_t
*zilog
, uint64_t foid
)
2746 * We should never attempt to call zil_commit on a snapshot for
2747 * a couple of reasons:
2749 * 1. A snapshot may never be modified, thus it cannot have any
2750 * in-flight itxs that would have modified the dataset.
2752 * 2. By design, when zil_commit() is called, a commit itx will
2753 * be assigned to this zilog; as a result, the zilog will be
2754 * dirtied. We must not dirty the zilog of a snapshot; there's
2755 * checks in the code that enforce this invariant, and will
2756 * cause a panic if it's not upheld.
2758 ASSERT3B(dmu_objset_is_snapshot(zilog
->zl_os
), ==, B_FALSE
);
2760 if (zilog
->zl_sync
== ZFS_SYNC_DISABLED
)
2763 if (!spa_writeable(zilog
->zl_spa
)) {
2765 * If the SPA is not writable, there should never be any
2766 * pending itxs waiting to be committed to disk. If that
2767 * weren't true, we'd skip writing those itxs out, and
2768 * would break the sematics of zil_commit(); thus, we're
2769 * verifying that truth before we return to the caller.
2771 ASSERT(list_is_empty(&zilog
->zl_lwb_list
));
2772 ASSERT3P(zilog
->zl_last_lwb_opened
, ==, NULL
);
2773 for (int i
= 0; i
< TXG_SIZE
; i
++)
2774 ASSERT3P(zilog
->zl_itxg
[i
].itxg_itxs
, ==, NULL
);
2779 * If the ZIL is suspended, we don't want to dirty it by calling
2780 * zil_commit_itx_assign() below, nor can we write out
2781 * lwbs like would be done in zil_commit_write(). Thus, we
2782 * simply rely on txg_wait_synced() to maintain the necessary
2783 * semantics, and avoid calling those functions altogether.
2785 if (zilog
->zl_suspend
> 0) {
2786 txg_wait_synced(zilog
->zl_dmu_pool
, 0);
2790 zil_commit_impl(zilog
, foid
);
2794 zil_commit_impl(zilog_t
*zilog
, uint64_t foid
)
2797 * Move the "async" itxs for the specified foid to the "sync"
2798 * queues, such that they will be later committed (or skipped)
2799 * to an lwb when zil_process_commit_list() is called.
2801 * Since these "async" itxs must be committed prior to this
2802 * call to zil_commit returning, we must perform this operation
2803 * before we call zil_commit_itx_assign().
2805 zil_async_to_sync(zilog
, foid
);
2808 * We allocate a new "waiter" structure which will initially be
2809 * linked to the commit itx using the itx's "itx_private" field.
2810 * Since the commit itx doesn't represent any on-disk state,
2811 * when it's committed to an lwb, rather than copying the its
2812 * lr_t into the lwb's buffer, the commit itx's "waiter" will be
2813 * added to the lwb's list of waiters. Then, when the lwb is
2814 * committed to stable storage, each waiter in the lwb's list of
2815 * waiters will be marked "done", and signalled.
2817 * We must create the waiter and assign the commit itx prior to
2818 * calling zil_commit_writer(), or else our specific commit itx
2819 * is not guaranteed to be committed to an lwb prior to calling
2820 * zil_commit_waiter().
2822 zil_commit_waiter_t
*zcw
= zil_alloc_commit_waiter();
2823 zil_commit_itx_assign(zilog
, zcw
);
2825 zil_commit_writer(zilog
, zcw
);
2826 zil_commit_waiter(zilog
, zcw
);
2828 if (zcw
->zcw_zio_error
!= 0) {
2830 * If there was an error writing out the ZIL blocks that
2831 * this thread is waiting on, then we fallback to
2832 * relying on spa_sync() to write out the data this
2833 * thread is waiting on. Obviously this has performance
2834 * implications, but the expectation is for this to be
2835 * an exceptional case, and shouldn't occur often.
2837 DTRACE_PROBE2(zil__commit__io__error
,
2838 zilog_t
*, zilog
, zil_commit_waiter_t
*, zcw
);
2839 txg_wait_synced(zilog
->zl_dmu_pool
, 0);
2842 zil_free_commit_waiter(zcw
);
2846 * Called in syncing context to free committed log blocks and update log header.
2849 zil_sync(zilog_t
*zilog
, dmu_tx_t
*tx
)
2851 zil_header_t
*zh
= zil_header_in_syncing_context(zilog
);
2852 uint64_t txg
= dmu_tx_get_txg(tx
);
2853 spa_t
*spa
= zilog
->zl_spa
;
2854 uint64_t *replayed_seq
= &zilog
->zl_replayed_seq
[txg
& TXG_MASK
];
2858 * We don't zero out zl_destroy_txg, so make sure we don't try
2859 * to destroy it twice.
2861 if (spa_sync_pass(spa
) != 1)
2864 mutex_enter(&zilog
->zl_lock
);
2866 ASSERT(zilog
->zl_stop_sync
== 0);
2868 if (*replayed_seq
!= 0) {
2869 ASSERT(zh
->zh_replay_seq
< *replayed_seq
);
2870 zh
->zh_replay_seq
= *replayed_seq
;
2874 if (zilog
->zl_destroy_txg
== txg
) {
2875 blkptr_t blk
= zh
->zh_log
;
2877 ASSERT(list_head(&zilog
->zl_lwb_list
) == NULL
);
2879 bzero(zh
, sizeof (zil_header_t
));
2880 bzero(zilog
->zl_replayed_seq
, sizeof (zilog
->zl_replayed_seq
));
2882 if (zilog
->zl_keep_first
) {
2884 * If this block was part of log chain that couldn't
2885 * be claimed because a device was missing during
2886 * zil_claim(), but that device later returns,
2887 * then this block could erroneously appear valid.
2888 * To guard against this, assign a new GUID to the new
2889 * log chain so it doesn't matter what blk points to.
2891 zil_init_log_chain(zilog
, &blk
);
2896 while ((lwb
= list_head(&zilog
->zl_lwb_list
)) != NULL
) {
2897 zh
->zh_log
= lwb
->lwb_blk
;
2898 if (lwb
->lwb_buf
!= NULL
|| lwb
->lwb_max_txg
> txg
)
2900 list_remove(&zilog
->zl_lwb_list
, lwb
);
2901 zio_free(spa
, txg
, &lwb
->lwb_blk
);
2902 zil_free_lwb(zilog
, lwb
);
2905 * If we don't have anything left in the lwb list then
2906 * we've had an allocation failure and we need to zero
2907 * out the zil_header blkptr so that we don't end
2908 * up freeing the same block twice.
2910 if (list_head(&zilog
->zl_lwb_list
) == NULL
)
2911 BP_ZERO(&zh
->zh_log
);
2913 mutex_exit(&zilog
->zl_lock
);
2918 zil_lwb_cons(void *vbuf
, void *unused
, int kmflag
)
2921 list_create(&lwb
->lwb_waiters
, sizeof (zil_commit_waiter_t
),
2922 offsetof(zil_commit_waiter_t
, zcw_node
));
2923 avl_create(&lwb
->lwb_vdev_tree
, zil_lwb_vdev_compare
,
2924 sizeof (zil_vdev_node_t
), offsetof(zil_vdev_node_t
, zv_node
));
2925 mutex_init(&lwb
->lwb_vdev_lock
, NULL
, MUTEX_DEFAULT
, NULL
);
2931 zil_lwb_dest(void *vbuf
, void *unused
)
2934 mutex_destroy(&lwb
->lwb_vdev_lock
);
2935 avl_destroy(&lwb
->lwb_vdev_tree
);
2936 list_destroy(&lwb
->lwb_waiters
);
2942 zil_lwb_cache
= kmem_cache_create("zil_lwb_cache",
2943 sizeof (lwb_t
), 0, zil_lwb_cons
, zil_lwb_dest
, NULL
, NULL
, NULL
, 0);
2945 zil_zcw_cache
= kmem_cache_create("zil_zcw_cache",
2946 sizeof (zil_commit_waiter_t
), 0, NULL
, NULL
, NULL
, NULL
, NULL
, 0);
2952 kmem_cache_destroy(zil_zcw_cache
);
2953 kmem_cache_destroy(zil_lwb_cache
);
2957 zil_set_sync(zilog_t
*zilog
, uint64_t sync
)
2959 zilog
->zl_sync
= sync
;
2963 zil_set_logbias(zilog_t
*zilog
, uint64_t logbias
)
2965 zilog
->zl_logbias
= logbias
;
2969 zil_alloc(objset_t
*os
, zil_header_t
*zh_phys
)
2973 zilog
= kmem_zalloc(sizeof (zilog_t
), KM_SLEEP
);
2975 zilog
->zl_header
= zh_phys
;
2977 zilog
->zl_spa
= dmu_objset_spa(os
);
2978 zilog
->zl_dmu_pool
= dmu_objset_pool(os
);
2979 zilog
->zl_destroy_txg
= TXG_INITIAL
- 1;
2980 zilog
->zl_logbias
= dmu_objset_logbias(os
);
2981 zilog
->zl_sync
= dmu_objset_syncprop(os
);
2982 zilog
->zl_dirty_max_txg
= 0;
2983 zilog
->zl_last_lwb_opened
= NULL
;
2984 zilog
->zl_last_lwb_latency
= 0;
2986 mutex_init(&zilog
->zl_lock
, NULL
, MUTEX_DEFAULT
, NULL
);
2987 mutex_init(&zilog
->zl_issuer_lock
, NULL
, MUTEX_DEFAULT
, NULL
);
2989 for (int i
= 0; i
< TXG_SIZE
; i
++) {
2990 mutex_init(&zilog
->zl_itxg
[i
].itxg_lock
, NULL
,
2991 MUTEX_DEFAULT
, NULL
);
2994 list_create(&zilog
->zl_lwb_list
, sizeof (lwb_t
),
2995 offsetof(lwb_t
, lwb_node
));
2997 list_create(&zilog
->zl_itx_commit_list
, sizeof (itx_t
),
2998 offsetof(itx_t
, itx_node
));
3000 cv_init(&zilog
->zl_cv_suspend
, NULL
, CV_DEFAULT
, NULL
);
3006 zil_free(zilog_t
*zilog
)
3008 zilog
->zl_stop_sync
= 1;
3010 ASSERT0(zilog
->zl_suspend
);
3011 ASSERT0(zilog
->zl_suspending
);
3013 ASSERT(list_is_empty(&zilog
->zl_lwb_list
));
3014 list_destroy(&zilog
->zl_lwb_list
);
3016 ASSERT(list_is_empty(&zilog
->zl_itx_commit_list
));
3017 list_destroy(&zilog
->zl_itx_commit_list
);
3019 for (int i
= 0; i
< TXG_SIZE
; i
++) {
3021 * It's possible for an itx to be generated that doesn't dirty
3022 * a txg (e.g. ztest TX_TRUNCATE). So there's no zil_clean()
3023 * callback to remove the entry. We remove those here.
3025 * Also free up the ziltest itxs.
3027 if (zilog
->zl_itxg
[i
].itxg_itxs
)
3028 zil_itxg_clean(zilog
->zl_itxg
[i
].itxg_itxs
);
3029 mutex_destroy(&zilog
->zl_itxg
[i
].itxg_lock
);
3032 mutex_destroy(&zilog
->zl_issuer_lock
);
3033 mutex_destroy(&zilog
->zl_lock
);
3035 cv_destroy(&zilog
->zl_cv_suspend
);
3037 kmem_free(zilog
, sizeof (zilog_t
));
3041 * Open an intent log.
3044 zil_open(objset_t
*os
, zil_get_data_t
*get_data
)
3046 zilog_t
*zilog
= dmu_objset_zil(os
);
3048 ASSERT3P(zilog
->zl_get_data
, ==, NULL
);
3049 ASSERT3P(zilog
->zl_last_lwb_opened
, ==, NULL
);
3050 ASSERT(list_is_empty(&zilog
->zl_lwb_list
));
3052 zilog
->zl_get_data
= get_data
;
3058 * Close an intent log.
3061 zil_close(zilog_t
*zilog
)
3066 if (!dmu_objset_is_snapshot(zilog
->zl_os
)) {
3067 zil_commit(zilog
, 0);
3069 ASSERT3P(list_tail(&zilog
->zl_lwb_list
), ==, NULL
);
3070 ASSERT0(zilog
->zl_dirty_max_txg
);
3071 ASSERT3B(zilog_is_dirty(zilog
), ==, B_FALSE
);
3074 mutex_enter(&zilog
->zl_lock
);
3075 lwb
= list_tail(&zilog
->zl_lwb_list
);
3077 txg
= zilog
->zl_dirty_max_txg
;
3079 txg
= MAX(zilog
->zl_dirty_max_txg
, lwb
->lwb_max_txg
);
3080 mutex_exit(&zilog
->zl_lock
);
3083 * We need to use txg_wait_synced() to wait long enough for the
3084 * ZIL to be clean, and to wait for all pending lwbs to be
3088 txg_wait_synced(zilog
->zl_dmu_pool
, txg
);
3090 if (zilog_is_dirty(zilog
))
3091 zfs_dbgmsg("zil (%p) is dirty, txg %llu", zilog
, txg
);
3092 if (txg
< spa_freeze_txg(zilog
->zl_spa
))
3093 VERIFY(!zilog_is_dirty(zilog
));
3095 zilog
->zl_get_data
= NULL
;
3098 * We should have only one lwb left on the list; remove it now.
3100 mutex_enter(&zilog
->zl_lock
);
3101 lwb
= list_head(&zilog
->zl_lwb_list
);
3103 ASSERT3P(lwb
, ==, list_tail(&zilog
->zl_lwb_list
));
3104 ASSERT3S(lwb
->lwb_state
, !=, LWB_STATE_ISSUED
);
3105 list_remove(&zilog
->zl_lwb_list
, lwb
);
3106 zio_buf_free(lwb
->lwb_buf
, lwb
->lwb_sz
);
3107 zil_free_lwb(zilog
, lwb
);
3109 mutex_exit(&zilog
->zl_lock
);
3112 static char *suspend_tag
= "zil suspending";
3115 * Suspend an intent log. While in suspended mode, we still honor
3116 * synchronous semantics, but we rely on txg_wait_synced() to do it.
3117 * On old version pools, we suspend the log briefly when taking a
3118 * snapshot so that it will have an empty intent log.
3120 * Long holds are not really intended to be used the way we do here --
3121 * held for such a short time. A concurrent caller of dsl_dataset_long_held()
3122 * could fail. Therefore we take pains to only put a long hold if it is
3123 * actually necessary. Fortunately, it will only be necessary if the
3124 * objset is currently mounted (or the ZVOL equivalent). In that case it
3125 * will already have a long hold, so we are not really making things any worse.
3127 * Ideally, we would locate the existing long-holder (i.e. the zfsvfs_t or
3128 * zvol_state_t), and use their mechanism to prevent their hold from being
3129 * dropped (e.g. VFS_HOLD()). However, that would be even more pain for
3132 * if cookiep == NULL, this does both the suspend & resume.
3133 * Otherwise, it returns with the dataset "long held", and the cookie
3134 * should be passed into zil_resume().
3137 zil_suspend(const char *osname
, void **cookiep
)
3141 const zil_header_t
*zh
;
3144 error
= dmu_objset_hold(osname
, suspend_tag
, &os
);
3147 zilog
= dmu_objset_zil(os
);
3149 mutex_enter(&zilog
->zl_lock
);
3150 zh
= zilog
->zl_header
;
3152 if (zh
->zh_flags
& ZIL_REPLAY_NEEDED
) { /* unplayed log */
3153 mutex_exit(&zilog
->zl_lock
);
3154 dmu_objset_rele(os
, suspend_tag
);
3155 return (SET_ERROR(EBUSY
));
3159 * Don't put a long hold in the cases where we can avoid it. This
3160 * is when there is no cookie so we are doing a suspend & resume
3161 * (i.e. called from zil_vdev_offline()), and there's nothing to do
3162 * for the suspend because it's already suspended, or there's no ZIL.
3164 if (cookiep
== NULL
&& !zilog
->zl_suspending
&&
3165 (zilog
->zl_suspend
> 0 || BP_IS_HOLE(&zh
->zh_log
))) {
3166 mutex_exit(&zilog
->zl_lock
);
3167 dmu_objset_rele(os
, suspend_tag
);
3171 dsl_dataset_long_hold(dmu_objset_ds(os
), suspend_tag
);
3172 dsl_pool_rele(dmu_objset_pool(os
), suspend_tag
);
3174 zilog
->zl_suspend
++;
3176 if (zilog
->zl_suspend
> 1) {
3178 * Someone else is already suspending it.
3179 * Just wait for them to finish.
3182 while (zilog
->zl_suspending
)
3183 cv_wait(&zilog
->zl_cv_suspend
, &zilog
->zl_lock
);
3184 mutex_exit(&zilog
->zl_lock
);
3186 if (cookiep
== NULL
)
3194 * If there is no pointer to an on-disk block, this ZIL must not
3195 * be active (e.g. filesystem not mounted), so there's nothing
3198 if (BP_IS_HOLE(&zh
->zh_log
)) {
3199 ASSERT(cookiep
!= NULL
); /* fast path already handled */
3202 mutex_exit(&zilog
->zl_lock
);
3207 * The ZIL has work to do. Ensure that the associated encryption
3208 * key will remain mapped while we are committing the log by
3209 * grabbing a reference to it. If the key isn't loaded we have no
3210 * choice but to return an error until the wrapping key is loaded.
3212 if (os
->os_encrypted
&&
3213 dsl_dataset_create_key_mapping(dmu_objset_ds(os
)) != 0) {
3214 zilog
->zl_suspend
--;
3215 mutex_exit(&zilog
->zl_lock
);
3216 dsl_dataset_long_rele(dmu_objset_ds(os
), suspend_tag
);
3217 dsl_dataset_rele(dmu_objset_ds(os
), suspend_tag
);
3218 return (SET_ERROR(EBUSY
));
3221 zilog
->zl_suspending
= B_TRUE
;
3222 mutex_exit(&zilog
->zl_lock
);
3225 * We need to use zil_commit_impl to ensure we wait for all
3226 * LWB_STATE_OPENED and LWB_STATE_ISSUED lwb's to be committed
3227 * to disk before proceeding. If we used zil_commit instead, it
3228 * would just call txg_wait_synced(), because zl_suspend is set.
3229 * txg_wait_synced() doesn't wait for these lwb's to be
3230 * LWB_STATE_FLUSH_DONE before returning.
3232 zil_commit_impl(zilog
, 0);
3235 * Now that we've ensured all lwb's are LWB_STATE_DONE,
3236 * txg_wait_synced() will be called from within zil_destroy(),
3237 * which will ensure the data from the zilog has migrated to the
3238 * main pool before it returns.
3240 txg_wait_synced(zilog
->zl_dmu_pool
, 0);
3242 zil_destroy(zilog
, B_FALSE
);
3244 mutex_enter(&zilog
->zl_lock
);
3245 zilog
->zl_suspending
= B_FALSE
;
3246 cv_broadcast(&zilog
->zl_cv_suspend
);
3247 mutex_exit(&zilog
->zl_lock
);
3249 if (os
->os_encrypted
)
3250 dsl_dataset_remove_key_mapping(dmu_objset_ds(os
));
3252 if (cookiep
== NULL
)
3260 zil_resume(void *cookie
)
3262 objset_t
*os
= cookie
;
3263 zilog_t
*zilog
= dmu_objset_zil(os
);
3265 mutex_enter(&zilog
->zl_lock
);
3266 ASSERT(zilog
->zl_suspend
!= 0);
3267 zilog
->zl_suspend
--;
3268 mutex_exit(&zilog
->zl_lock
);
3269 dsl_dataset_long_rele(dmu_objset_ds(os
), suspend_tag
);
3270 dsl_dataset_rele(dmu_objset_ds(os
), suspend_tag
);
3273 typedef struct zil_replay_arg
{
3274 zil_replay_func_t
**zr_replay
;
3276 boolean_t zr_byteswap
;
3281 zil_replay_error(zilog_t
*zilog
, lr_t
*lr
, int error
)
3283 char name
[ZFS_MAX_DATASET_NAME_LEN
];
3285 zilog
->zl_replaying_seq
--; /* didn't actually replay this one */
3287 dmu_objset_name(zilog
->zl_os
, name
);
3289 cmn_err(CE_WARN
, "ZFS replay transaction error %d, "
3290 "dataset %s, seq 0x%llx, txtype %llu %s\n", error
, name
,
3291 (u_longlong_t
)lr
->lrc_seq
,
3292 (u_longlong_t
)(lr
->lrc_txtype
& ~TX_CI
),
3293 (lr
->lrc_txtype
& TX_CI
) ? "CI" : "");
3299 zil_replay_log_record(zilog_t
*zilog
, lr_t
*lr
, void *zra
, uint64_t claim_txg
)
3301 zil_replay_arg_t
*zr
= zra
;
3302 const zil_header_t
*zh
= zilog
->zl_header
;
3303 uint64_t reclen
= lr
->lrc_reclen
;
3304 uint64_t txtype
= lr
->lrc_txtype
;
3307 zilog
->zl_replaying_seq
= lr
->lrc_seq
;
3309 if (lr
->lrc_seq
<= zh
->zh_replay_seq
) /* already replayed */
3312 if (lr
->lrc_txg
< claim_txg
) /* already committed */
3315 /* Strip case-insensitive bit, still present in log record */
3318 if (txtype
== 0 || txtype
>= TX_MAX_TYPE
)
3319 return (zil_replay_error(zilog
, lr
, EINVAL
));
3322 * If this record type can be logged out of order, the object
3323 * (lr_foid) may no longer exist. That's legitimate, not an error.
3325 if (TX_OOO(txtype
)) {
3326 error
= dmu_object_info(zilog
->zl_os
,
3327 LR_FOID_GET_OBJ(((lr_ooo_t
*)lr
)->lr_foid
), NULL
);
3328 if (error
== ENOENT
|| error
== EEXIST
)
3333 * Make a copy of the data so we can revise and extend it.
3335 bcopy(lr
, zr
->zr_lr
, reclen
);
3338 * If this is a TX_WRITE with a blkptr, suck in the data.
3340 if (txtype
== TX_WRITE
&& reclen
== sizeof (lr_write_t
)) {
3341 error
= zil_read_log_data(zilog
, (lr_write_t
*)lr
,
3342 zr
->zr_lr
+ reclen
);
3344 return (zil_replay_error(zilog
, lr
, error
));
3348 * The log block containing this lr may have been byteswapped
3349 * so that we can easily examine common fields like lrc_txtype.
3350 * However, the log is a mix of different record types, and only the
3351 * replay vectors know how to byteswap their records. Therefore, if
3352 * the lr was byteswapped, undo it before invoking the replay vector.
3354 if (zr
->zr_byteswap
)
3355 byteswap_uint64_array(zr
->zr_lr
, reclen
);
3358 * We must now do two things atomically: replay this log record,
3359 * and update the log header sequence number to reflect the fact that
3360 * we did so. At the end of each replay function the sequence number
3361 * is updated if we are in replay mode.
3363 error
= zr
->zr_replay
[txtype
](zr
->zr_arg
, zr
->zr_lr
, zr
->zr_byteswap
);
3366 * The DMU's dnode layer doesn't see removes until the txg
3367 * commits, so a subsequent claim can spuriously fail with
3368 * EEXIST. So if we receive any error we try syncing out
3369 * any removes then retry the transaction. Note that we
3370 * specify B_FALSE for byteswap now, so we don't do it twice.
3372 txg_wait_synced(spa_get_dsl(zilog
->zl_spa
), 0);
3373 error
= zr
->zr_replay
[txtype
](zr
->zr_arg
, zr
->zr_lr
, B_FALSE
);
3375 return (zil_replay_error(zilog
, lr
, error
));
3382 zil_incr_blks(zilog_t
*zilog
, blkptr_t
*bp
, void *arg
, uint64_t claim_txg
)
3384 zilog
->zl_replay_blks
++;
3390 * If this dataset has a non-empty intent log, replay it and destroy it.
3393 zil_replay(objset_t
*os
, void *arg
, zil_replay_func_t
*replay_func
[TX_MAX_TYPE
])
3395 zilog_t
*zilog
= dmu_objset_zil(os
);
3396 const zil_header_t
*zh
= zilog
->zl_header
;
3397 zil_replay_arg_t zr
;
3399 if ((zh
->zh_flags
& ZIL_REPLAY_NEEDED
) == 0) {
3400 zil_destroy(zilog
, B_TRUE
);
3404 zr
.zr_replay
= replay_func
;
3406 zr
.zr_byteswap
= BP_SHOULD_BYTESWAP(&zh
->zh_log
);
3407 zr
.zr_lr
= kmem_alloc(2 * SPA_MAXBLOCKSIZE
, KM_SLEEP
);
3410 * Wait for in-progress removes to sync before starting replay.
3412 txg_wait_synced(zilog
->zl_dmu_pool
, 0);
3414 zilog
->zl_replay
= B_TRUE
;
3415 zilog
->zl_replay_time
= ddi_get_lbolt();
3416 ASSERT(zilog
->zl_replay_blks
== 0);
3417 (void) zil_parse(zilog
, zil_incr_blks
, zil_replay_log_record
, &zr
,
3418 zh
->zh_claim_txg
, B_TRUE
);
3419 kmem_free(zr
.zr_lr
, 2 * SPA_MAXBLOCKSIZE
);
3421 zil_destroy(zilog
, B_FALSE
);
3422 txg_wait_synced(zilog
->zl_dmu_pool
, zilog
->zl_destroy_txg
);
3423 zilog
->zl_replay
= B_FALSE
;
3427 zil_replaying(zilog_t
*zilog
, dmu_tx_t
*tx
)
3429 if (zilog
->zl_sync
== ZFS_SYNC_DISABLED
)
3432 if (zilog
->zl_replay
) {
3433 dsl_dataset_dirty(dmu_objset_ds(zilog
->zl_os
), tx
);
3434 zilog
->zl_replayed_seq
[dmu_tx_get_txg(tx
) & TXG_MASK
] =
3435 zilog
->zl_replaying_seq
;
3444 zil_reset(const char *osname
, void *arg
)
3448 error
= zil_suspend(osname
, NULL
);
3450 return (SET_ERROR(EEXIST
));