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 if (DVA_GET_VDEV(dva1
) < DVA_GET_VDEV(dva2
))
128 if (DVA_GET_VDEV(dva1
) > DVA_GET_VDEV(dva2
))
131 if (DVA_GET_OFFSET(dva1
) < DVA_GET_OFFSET(dva2
))
133 if (DVA_GET_OFFSET(dva1
) > DVA_GET_OFFSET(dva2
))
140 zil_bp_tree_init(zilog_t
*zilog
)
142 avl_create(&zilog
->zl_bp_tree
, zil_bp_compare
,
143 sizeof (zil_bp_node_t
), offsetof(zil_bp_node_t
, zn_node
));
147 zil_bp_tree_fini(zilog_t
*zilog
)
149 avl_tree_t
*t
= &zilog
->zl_bp_tree
;
153 while ((zn
= avl_destroy_nodes(t
, &cookie
)) != NULL
)
154 kmem_free(zn
, sizeof (zil_bp_node_t
));
160 zil_bp_tree_add(zilog_t
*zilog
, const blkptr_t
*bp
)
162 avl_tree_t
*t
= &zilog
->zl_bp_tree
;
167 if (BP_IS_EMBEDDED(bp
))
170 dva
= BP_IDENTITY(bp
);
172 if (avl_find(t
, dva
, &where
) != NULL
)
173 return (SET_ERROR(EEXIST
));
175 zn
= kmem_alloc(sizeof (zil_bp_node_t
), KM_SLEEP
);
177 avl_insert(t
, zn
, where
);
182 static zil_header_t
*
183 zil_header_in_syncing_context(zilog_t
*zilog
)
185 return ((zil_header_t
*)zilog
->zl_header
);
189 zil_init_log_chain(zilog_t
*zilog
, blkptr_t
*bp
)
191 zio_cksum_t
*zc
= &bp
->blk_cksum
;
193 zc
->zc_word
[ZIL_ZC_GUID_0
] = spa_get_random(-1ULL);
194 zc
->zc_word
[ZIL_ZC_GUID_1
] = spa_get_random(-1ULL);
195 zc
->zc_word
[ZIL_ZC_OBJSET
] = dmu_objset_id(zilog
->zl_os
);
196 zc
->zc_word
[ZIL_ZC_SEQ
] = 1ULL;
200 * Read a log block and make sure it's valid.
203 zil_read_log_block(zilog_t
*zilog
, const blkptr_t
*bp
, blkptr_t
*nbp
, void *dst
,
206 enum zio_flag zio_flags
= ZIO_FLAG_CANFAIL
;
207 arc_flags_t aflags
= ARC_FLAG_WAIT
;
208 arc_buf_t
*abuf
= NULL
;
212 if (zilog
->zl_header
->zh_claim_txg
== 0)
213 zio_flags
|= ZIO_FLAG_SPECULATIVE
| ZIO_FLAG_SCRUB
;
215 if (!(zilog
->zl_header
->zh_flags
& ZIL_CLAIM_LR_SEQ_VALID
))
216 zio_flags
|= ZIO_FLAG_SPECULATIVE
;
218 SET_BOOKMARK(&zb
, bp
->blk_cksum
.zc_word
[ZIL_ZC_OBJSET
],
219 ZB_ZIL_OBJECT
, ZB_ZIL_LEVEL
, bp
->blk_cksum
.zc_word
[ZIL_ZC_SEQ
]);
221 error
= arc_read(NULL
, zilog
->zl_spa
, bp
, arc_getbuf_func
, &abuf
,
222 ZIO_PRIORITY_SYNC_READ
, zio_flags
, &aflags
, &zb
);
225 zio_cksum_t cksum
= bp
->blk_cksum
;
228 * Validate the checksummed log block.
230 * Sequence numbers should be... sequential. The checksum
231 * verifier for the next block should be bp's checksum plus 1.
233 * Also check the log chain linkage and size used.
235 cksum
.zc_word
[ZIL_ZC_SEQ
]++;
237 if (BP_GET_CHECKSUM(bp
) == ZIO_CHECKSUM_ZILOG2
) {
238 zil_chain_t
*zilc
= abuf
->b_data
;
239 char *lr
= (char *)(zilc
+ 1);
240 uint64_t len
= zilc
->zc_nused
- sizeof (zil_chain_t
);
242 if (bcmp(&cksum
, &zilc
->zc_next_blk
.blk_cksum
,
243 sizeof (cksum
)) || BP_IS_HOLE(&zilc
->zc_next_blk
)) {
244 error
= SET_ERROR(ECKSUM
);
246 ASSERT3U(len
, <=, SPA_OLD_MAXBLOCKSIZE
);
248 *end
= (char *)dst
+ len
;
249 *nbp
= zilc
->zc_next_blk
;
252 char *lr
= abuf
->b_data
;
253 uint64_t size
= BP_GET_LSIZE(bp
);
254 zil_chain_t
*zilc
= (zil_chain_t
*)(lr
+ size
) - 1;
256 if (bcmp(&cksum
, &zilc
->zc_next_blk
.blk_cksum
,
257 sizeof (cksum
)) || BP_IS_HOLE(&zilc
->zc_next_blk
) ||
258 (zilc
->zc_nused
> (size
- sizeof (*zilc
)))) {
259 error
= SET_ERROR(ECKSUM
);
261 ASSERT3U(zilc
->zc_nused
, <=,
262 SPA_OLD_MAXBLOCKSIZE
);
263 bcopy(lr
, dst
, zilc
->zc_nused
);
264 *end
= (char *)dst
+ zilc
->zc_nused
;
265 *nbp
= zilc
->zc_next_blk
;
269 arc_buf_destroy(abuf
, &abuf
);
276 * Read a TX_WRITE log data block.
279 zil_read_log_data(zilog_t
*zilog
, const lr_write_t
*lr
, void *wbuf
)
281 enum zio_flag zio_flags
= ZIO_FLAG_CANFAIL
;
282 const blkptr_t
*bp
= &lr
->lr_blkptr
;
283 arc_flags_t aflags
= ARC_FLAG_WAIT
;
284 arc_buf_t
*abuf
= NULL
;
288 if (BP_IS_HOLE(bp
)) {
290 bzero(wbuf
, MAX(BP_GET_LSIZE(bp
), lr
->lr_length
));
294 if (zilog
->zl_header
->zh_claim_txg
== 0)
295 zio_flags
|= ZIO_FLAG_SPECULATIVE
| ZIO_FLAG_SCRUB
;
297 SET_BOOKMARK(&zb
, dmu_objset_id(zilog
->zl_os
), lr
->lr_foid
,
298 ZB_ZIL_LEVEL
, lr
->lr_offset
/ BP_GET_LSIZE(bp
));
300 error
= arc_read(NULL
, zilog
->zl_spa
, bp
, arc_getbuf_func
, &abuf
,
301 ZIO_PRIORITY_SYNC_READ
, zio_flags
, &aflags
, &zb
);
305 bcopy(abuf
->b_data
, wbuf
, arc_buf_size(abuf
));
306 arc_buf_destroy(abuf
, &abuf
);
313 * Parse the intent log, and call parse_func for each valid record within.
316 zil_parse(zilog_t
*zilog
, zil_parse_blk_func_t
*parse_blk_func
,
317 zil_parse_lr_func_t
*parse_lr_func
, void *arg
, uint64_t txg
)
319 const zil_header_t
*zh
= zilog
->zl_header
;
320 boolean_t claimed
= !!zh
->zh_claim_txg
;
321 uint64_t claim_blk_seq
= claimed
? zh
->zh_claim_blk_seq
: UINT64_MAX
;
322 uint64_t claim_lr_seq
= claimed
? zh
->zh_claim_lr_seq
: UINT64_MAX
;
323 uint64_t max_blk_seq
= 0;
324 uint64_t max_lr_seq
= 0;
325 uint64_t blk_count
= 0;
326 uint64_t lr_count
= 0;
327 blkptr_t blk
, next_blk
;
332 * Old logs didn't record the maximum zh_claim_lr_seq.
334 if (!(zh
->zh_flags
& ZIL_CLAIM_LR_SEQ_VALID
))
335 claim_lr_seq
= UINT64_MAX
;
338 * Starting at the block pointed to by zh_log we read the log chain.
339 * For each block in the chain we strongly check that block to
340 * ensure its validity. We stop when an invalid block is found.
341 * For each block pointer in the chain we call parse_blk_func().
342 * For each record in each valid block we call parse_lr_func().
343 * If the log has been claimed, stop if we encounter a sequence
344 * number greater than the highest claimed sequence number.
346 lrbuf
= zio_buf_alloc(SPA_OLD_MAXBLOCKSIZE
);
347 zil_bp_tree_init(zilog
);
349 for (blk
= zh
->zh_log
; !BP_IS_HOLE(&blk
); blk
= next_blk
) {
350 uint64_t blk_seq
= blk
.blk_cksum
.zc_word
[ZIL_ZC_SEQ
];
354 if (blk_seq
> claim_blk_seq
)
356 if ((error
= parse_blk_func(zilog
, &blk
, arg
, txg
)) != 0)
358 ASSERT3U(max_blk_seq
, <, blk_seq
);
359 max_blk_seq
= blk_seq
;
362 if (max_lr_seq
== claim_lr_seq
&& max_blk_seq
== claim_blk_seq
)
365 error
= zil_read_log_block(zilog
, &blk
, &next_blk
, lrbuf
, &end
);
369 for (lrp
= lrbuf
; lrp
< end
; lrp
+= reclen
) {
370 lr_t
*lr
= (lr_t
*)lrp
;
371 reclen
= lr
->lrc_reclen
;
372 ASSERT3U(reclen
, >=, sizeof (lr_t
));
373 if (lr
->lrc_seq
> claim_lr_seq
)
375 if ((error
= parse_lr_func(zilog
, lr
, arg
, txg
)) != 0)
377 ASSERT3U(max_lr_seq
, <, lr
->lrc_seq
);
378 max_lr_seq
= lr
->lrc_seq
;
383 zilog
->zl_parse_error
= error
;
384 zilog
->zl_parse_blk_seq
= max_blk_seq
;
385 zilog
->zl_parse_lr_seq
= max_lr_seq
;
386 zilog
->zl_parse_blk_count
= blk_count
;
387 zilog
->zl_parse_lr_count
= lr_count
;
389 ASSERT(!claimed
|| !(zh
->zh_flags
& ZIL_CLAIM_LR_SEQ_VALID
) ||
390 (max_blk_seq
== claim_blk_seq
&& max_lr_seq
== claim_lr_seq
));
392 zil_bp_tree_fini(zilog
);
393 zio_buf_free(lrbuf
, SPA_OLD_MAXBLOCKSIZE
);
400 zil_clear_log_block(zilog_t
*zilog
, blkptr_t
*bp
, void *tx
, uint64_t first_txg
)
402 ASSERT(!BP_IS_HOLE(bp
));
405 * As we call this function from the context of a rewind to a
406 * checkpoint, each ZIL block whose txg is later than the txg
407 * that we rewind to is invalid. Thus, we return -1 so
408 * zil_parse() doesn't attempt to read it.
410 if (bp
->blk_birth
>= first_txg
)
413 if (zil_bp_tree_add(zilog
, bp
) != 0)
416 zio_free(zilog
->zl_spa
, first_txg
, bp
);
422 zil_noop_log_record(zilog_t
*zilog
, lr_t
*lrc
, void *tx
, uint64_t first_txg
)
428 zil_claim_log_block(zilog_t
*zilog
, blkptr_t
*bp
, void *tx
, uint64_t first_txg
)
431 * Claim log block if not already committed and not already claimed.
432 * If tx == NULL, just verify that the block is claimable.
434 if (BP_IS_HOLE(bp
) || bp
->blk_birth
< first_txg
||
435 zil_bp_tree_add(zilog
, bp
) != 0)
438 return (zio_wait(zio_claim(NULL
, zilog
->zl_spa
,
439 tx
== NULL
? 0 : first_txg
, bp
, spa_claim_notify
, NULL
,
440 ZIO_FLAG_CANFAIL
| ZIO_FLAG_SPECULATIVE
| ZIO_FLAG_SCRUB
)));
444 zil_claim_log_record(zilog_t
*zilog
, lr_t
*lrc
, void *tx
, uint64_t first_txg
)
446 lr_write_t
*lr
= (lr_write_t
*)lrc
;
449 if (lrc
->lrc_txtype
!= TX_WRITE
)
453 * If the block is not readable, don't claim it. This can happen
454 * in normal operation when a log block is written to disk before
455 * some of the dmu_sync() blocks it points to. In this case, the
456 * transaction cannot have been committed to anyone (we would have
457 * waited for all writes to be stable first), so it is semantically
458 * correct to declare this the end of the log.
460 if (lr
->lr_blkptr
.blk_birth
>= first_txg
&&
461 (error
= zil_read_log_data(zilog
, lr
, NULL
)) != 0)
463 return (zil_claim_log_block(zilog
, &lr
->lr_blkptr
, tx
, first_txg
));
468 zil_free_log_block(zilog_t
*zilog
, blkptr_t
*bp
, void *tx
, uint64_t claim_txg
)
470 zio_free(zilog
->zl_spa
, dmu_tx_get_txg(tx
), bp
);
476 zil_free_log_record(zilog_t
*zilog
, lr_t
*lrc
, void *tx
, uint64_t claim_txg
)
478 lr_write_t
*lr
= (lr_write_t
*)lrc
;
479 blkptr_t
*bp
= &lr
->lr_blkptr
;
482 * If we previously claimed it, we need to free it.
484 if (claim_txg
!= 0 && lrc
->lrc_txtype
== TX_WRITE
&&
485 bp
->blk_birth
>= claim_txg
&& zil_bp_tree_add(zilog
, bp
) == 0 &&
487 zio_free(zilog
->zl_spa
, dmu_tx_get_txg(tx
), bp
);
493 zil_lwb_vdev_compare(const void *x1
, const void *x2
)
495 const uint64_t v1
= ((zil_vdev_node_t
*)x1
)->zv_vdev
;
496 const uint64_t v2
= ((zil_vdev_node_t
*)x2
)->zv_vdev
;
507 zil_alloc_lwb(zilog_t
*zilog
, blkptr_t
*bp
, boolean_t slog
, uint64_t txg
)
511 lwb
= kmem_cache_alloc(zil_lwb_cache
, KM_SLEEP
);
512 lwb
->lwb_zilog
= zilog
;
514 lwb
->lwb_slog
= slog
;
515 lwb
->lwb_state
= LWB_STATE_CLOSED
;
516 lwb
->lwb_buf
= zio_buf_alloc(BP_GET_LSIZE(bp
));
517 lwb
->lwb_max_txg
= txg
;
518 lwb
->lwb_write_zio
= NULL
;
519 lwb
->lwb_root_zio
= NULL
;
521 lwb
->lwb_issued_timestamp
= 0;
522 if (BP_GET_CHECKSUM(bp
) == ZIO_CHECKSUM_ZILOG2
) {
523 lwb
->lwb_nused
= sizeof (zil_chain_t
);
524 lwb
->lwb_sz
= BP_GET_LSIZE(bp
);
527 lwb
->lwb_sz
= BP_GET_LSIZE(bp
) - sizeof (zil_chain_t
);
530 mutex_enter(&zilog
->zl_lock
);
531 list_insert_tail(&zilog
->zl_lwb_list
, lwb
);
532 mutex_exit(&zilog
->zl_lock
);
534 ASSERT(!MUTEX_HELD(&lwb
->lwb_vdev_lock
));
535 ASSERT(avl_is_empty(&lwb
->lwb_vdev_tree
));
536 VERIFY(list_is_empty(&lwb
->lwb_waiters
));
542 zil_free_lwb(zilog_t
*zilog
, lwb_t
*lwb
)
544 ASSERT(MUTEX_HELD(&zilog
->zl_lock
));
545 ASSERT(!MUTEX_HELD(&lwb
->lwb_vdev_lock
));
546 VERIFY(list_is_empty(&lwb
->lwb_waiters
));
547 ASSERT(avl_is_empty(&lwb
->lwb_vdev_tree
));
548 ASSERT3P(lwb
->lwb_write_zio
, ==, NULL
);
549 ASSERT3P(lwb
->lwb_root_zio
, ==, NULL
);
550 ASSERT3U(lwb
->lwb_max_txg
, <=, spa_syncing_txg(zilog
->zl_spa
));
551 ASSERT(lwb
->lwb_state
== LWB_STATE_CLOSED
||
552 lwb
->lwb_state
== LWB_STATE_FLUSH_DONE
);
555 * Clear the zilog's field to indicate this lwb is no longer
556 * valid, and prevent use-after-free errors.
558 if (zilog
->zl_last_lwb_opened
== lwb
)
559 zilog
->zl_last_lwb_opened
= NULL
;
561 kmem_cache_free(zil_lwb_cache
, lwb
);
565 * Called when we create in-memory log transactions so that we know
566 * to cleanup the itxs at the end of spa_sync().
569 zilog_dirty(zilog_t
*zilog
, uint64_t txg
)
571 dsl_pool_t
*dp
= zilog
->zl_dmu_pool
;
572 dsl_dataset_t
*ds
= dmu_objset_ds(zilog
->zl_os
);
574 ASSERT(spa_writeable(zilog
->zl_spa
));
576 if (ds
->ds_is_snapshot
)
577 panic("dirtying snapshot!");
579 if (txg_list_add(&dp
->dp_dirty_zilogs
, zilog
, txg
)) {
580 /* up the hold count until we can be written out */
581 dmu_buf_add_ref(ds
->ds_dbuf
, zilog
);
583 zilog
->zl_dirty_max_txg
= MAX(txg
, zilog
->zl_dirty_max_txg
);
588 * Determine if the zil is dirty in the specified txg. Callers wanting to
589 * ensure that the dirty state does not change must hold the itxg_lock for
590 * the specified txg. Holding the lock will ensure that the zil cannot be
591 * dirtied (zil_itx_assign) or cleaned (zil_clean) while we check its current
595 zilog_is_dirty_in_txg(zilog_t
*zilog
, uint64_t txg
)
597 dsl_pool_t
*dp
= zilog
->zl_dmu_pool
;
599 if (txg_list_member(&dp
->dp_dirty_zilogs
, zilog
, txg
& TXG_MASK
))
605 * Determine if the zil is dirty. The zil is considered dirty if it has
606 * any pending itx records that have not been cleaned by zil_clean().
609 zilog_is_dirty(zilog_t
*zilog
)
611 dsl_pool_t
*dp
= zilog
->zl_dmu_pool
;
613 for (int t
= 0; t
< TXG_SIZE
; t
++) {
614 if (txg_list_member(&dp
->dp_dirty_zilogs
, zilog
, t
))
621 * Create an on-disk intent log.
624 zil_create(zilog_t
*zilog
)
626 const zil_header_t
*zh
= zilog
->zl_header
;
632 boolean_t slog
= FALSE
;
635 * Wait for any previous destroy to complete.
637 txg_wait_synced(zilog
->zl_dmu_pool
, zilog
->zl_destroy_txg
);
639 ASSERT(zh
->zh_claim_txg
== 0);
640 ASSERT(zh
->zh_replay_seq
== 0);
645 * Allocate an initial log block if:
646 * - there isn't one already
647 * - the existing block is the wrong endianess
649 if (BP_IS_HOLE(&blk
) || BP_SHOULD_BYTESWAP(&blk
)) {
650 tx
= dmu_tx_create(zilog
->zl_os
);
651 VERIFY0(dmu_tx_assign(tx
, TXG_WAIT
));
652 dsl_dataset_dirty(dmu_objset_ds(zilog
->zl_os
), tx
);
653 txg
= dmu_tx_get_txg(tx
);
655 if (!BP_IS_HOLE(&blk
)) {
656 zio_free(zilog
->zl_spa
, txg
, &blk
);
660 error
= zio_alloc_zil(zilog
->zl_spa
,
661 zilog
->zl_os
->os_dsl_dataset
->ds_object
, txg
, &blk
, NULL
,
662 ZIL_MIN_BLKSZ
, &slog
);
665 zil_init_log_chain(zilog
, &blk
);
669 * Allocate a log write block (lwb) for the first log block.
672 lwb
= zil_alloc_lwb(zilog
, &blk
, slog
, txg
);
675 * If we just allocated the first log block, commit our transaction
676 * and wait for zil_sync() to stuff the block poiner into zh_log.
677 * (zh is part of the MOS, so we cannot modify it in open context.)
681 txg_wait_synced(zilog
->zl_dmu_pool
, txg
);
684 ASSERT(bcmp(&blk
, &zh
->zh_log
, sizeof (blk
)) == 0);
690 * In one tx, free all log blocks and clear the log header. If keep_first
691 * is set, then we're replaying a log with no content. We want to keep the
692 * first block, however, so that the first synchronous transaction doesn't
693 * require a txg_wait_synced() in zil_create(). We don't need to
694 * txg_wait_synced() here either when keep_first is set, because both
695 * zil_create() and zil_destroy() will wait for any in-progress destroys
699 zil_destroy(zilog_t
*zilog
, boolean_t keep_first
)
701 const zil_header_t
*zh
= zilog
->zl_header
;
707 * Wait for any previous destroy to complete.
709 txg_wait_synced(zilog
->zl_dmu_pool
, zilog
->zl_destroy_txg
);
711 zilog
->zl_old_header
= *zh
; /* debugging aid */
713 if (BP_IS_HOLE(&zh
->zh_log
))
716 tx
= dmu_tx_create(zilog
->zl_os
);
717 VERIFY0(dmu_tx_assign(tx
, TXG_WAIT
));
718 dsl_dataset_dirty(dmu_objset_ds(zilog
->zl_os
), tx
);
719 txg
= dmu_tx_get_txg(tx
);
721 mutex_enter(&zilog
->zl_lock
);
723 ASSERT3U(zilog
->zl_destroy_txg
, <, txg
);
724 zilog
->zl_destroy_txg
= txg
;
725 zilog
->zl_keep_first
= keep_first
;
727 if (!list_is_empty(&zilog
->zl_lwb_list
)) {
728 ASSERT(zh
->zh_claim_txg
== 0);
730 while ((lwb
= list_head(&zilog
->zl_lwb_list
)) != NULL
) {
731 list_remove(&zilog
->zl_lwb_list
, lwb
);
732 if (lwb
->lwb_buf
!= NULL
)
733 zio_buf_free(lwb
->lwb_buf
, lwb
->lwb_sz
);
734 zio_free(zilog
->zl_spa
, txg
, &lwb
->lwb_blk
);
735 zil_free_lwb(zilog
, lwb
);
737 } else if (!keep_first
) {
738 zil_destroy_sync(zilog
, tx
);
740 mutex_exit(&zilog
->zl_lock
);
746 zil_destroy_sync(zilog_t
*zilog
, dmu_tx_t
*tx
)
748 ASSERT(list_is_empty(&zilog
->zl_lwb_list
));
749 (void) zil_parse(zilog
, zil_free_log_block
,
750 zil_free_log_record
, tx
, zilog
->zl_header
->zh_claim_txg
);
754 zil_claim(dsl_pool_t
*dp
, dsl_dataset_t
*ds
, void *txarg
)
756 dmu_tx_t
*tx
= txarg
;
763 error
= dmu_objset_own_obj(dp
, ds
->ds_object
,
764 DMU_OST_ANY
, B_FALSE
, FTAG
, &os
);
767 * EBUSY indicates that the objset is inconsistent, in which
768 * case it can not have a ZIL.
770 if (error
!= EBUSY
) {
771 cmn_err(CE_WARN
, "can't open objset for %llu, error %u",
772 (unsigned long long)ds
->ds_object
, error
);
777 zilog
= dmu_objset_zil(os
);
778 zh
= zil_header_in_syncing_context(zilog
);
779 ASSERT3U(tx
->tx_txg
, ==, spa_first_txg(zilog
->zl_spa
));
780 first_txg
= spa_min_claim_txg(zilog
->zl_spa
);
783 * If the spa_log_state is not set to be cleared, check whether
784 * the current uberblock is a checkpoint one and if the current
785 * header has been claimed before moving on.
787 * If the current uberblock is a checkpointed uberblock then
788 * one of the following scenarios took place:
790 * 1] We are currently rewinding to the checkpoint of the pool.
791 * 2] We crashed in the middle of a checkpoint rewind but we
792 * did manage to write the checkpointed uberblock to the
793 * vdev labels, so when we tried to import the pool again
794 * the checkpointed uberblock was selected from the import
797 * In both cases we want to zero out all the ZIL blocks, except
798 * the ones that have been claimed at the time of the checkpoint
799 * (their zh_claim_txg != 0). The reason is that these blocks
800 * may be corrupted since we may have reused their locations on
801 * disk after we took the checkpoint.
803 * We could try to set spa_log_state to SPA_LOG_CLEAR earlier
804 * when we first figure out whether the current uberblock is
805 * checkpointed or not. Unfortunately, that would discard all
806 * the logs, including the ones that are claimed, and we would
809 if (spa_get_log_state(zilog
->zl_spa
) == SPA_LOG_CLEAR
||
810 (zilog
->zl_spa
->spa_uberblock
.ub_checkpoint_txg
!= 0 &&
811 zh
->zh_claim_txg
== 0)) {
812 if (!BP_IS_HOLE(&zh
->zh_log
)) {
813 (void) zil_parse(zilog
, zil_clear_log_block
,
814 zil_noop_log_record
, tx
, first_txg
);
816 BP_ZERO(&zh
->zh_log
);
817 dsl_dataset_dirty(dmu_objset_ds(os
), tx
);
818 dmu_objset_disown(os
, FTAG
);
823 * If we are not rewinding and opening the pool normally, then
824 * the min_claim_txg should be equal to the first txg of the pool.
826 ASSERT3U(first_txg
, ==, spa_first_txg(zilog
->zl_spa
));
829 * Claim all log blocks if we haven't already done so, and remember
830 * the highest claimed sequence number. This ensures that if we can
831 * read only part of the log now (e.g. due to a missing device),
832 * but we can read the entire log later, we will not try to replay
833 * or destroy beyond the last block we successfully claimed.
835 ASSERT3U(zh
->zh_claim_txg
, <=, first_txg
);
836 if (zh
->zh_claim_txg
== 0 && !BP_IS_HOLE(&zh
->zh_log
)) {
837 (void) zil_parse(zilog
, zil_claim_log_block
,
838 zil_claim_log_record
, tx
, first_txg
);
839 zh
->zh_claim_txg
= first_txg
;
840 zh
->zh_claim_blk_seq
= zilog
->zl_parse_blk_seq
;
841 zh
->zh_claim_lr_seq
= zilog
->zl_parse_lr_seq
;
842 if (zilog
->zl_parse_lr_count
|| zilog
->zl_parse_blk_count
> 1)
843 zh
->zh_flags
|= ZIL_REPLAY_NEEDED
;
844 zh
->zh_flags
|= ZIL_CLAIM_LR_SEQ_VALID
;
845 dsl_dataset_dirty(dmu_objset_ds(os
), tx
);
848 ASSERT3U(first_txg
, ==, (spa_last_synced_txg(zilog
->zl_spa
) + 1));
849 dmu_objset_disown(os
, FTAG
);
854 * Check the log by walking the log chain.
855 * Checksum errors are ok as they indicate the end of the chain.
856 * Any other error (no device or read failure) returns an error.
860 zil_check_log_chain(dsl_pool_t
*dp
, dsl_dataset_t
*ds
, void *tx
)
869 error
= dmu_objset_from_ds(ds
, &os
);
871 cmn_err(CE_WARN
, "can't open objset %llu, error %d",
872 (unsigned long long)ds
->ds_object
, error
);
876 zilog
= dmu_objset_zil(os
);
877 bp
= (blkptr_t
*)&zilog
->zl_header
->zh_log
;
879 if (!BP_IS_HOLE(bp
)) {
881 boolean_t valid
= B_TRUE
;
884 * Check the first block and determine if it's on a log device
885 * which may have been removed or faulted prior to loading this
886 * pool. If so, there's no point in checking the rest of the
887 * log as its content should have already been synced to the
890 spa_config_enter(os
->os_spa
, SCL_STATE
, FTAG
, RW_READER
);
891 vd
= vdev_lookup_top(os
->os_spa
, DVA_GET_VDEV(&bp
->blk_dva
[0]));
892 if (vd
->vdev_islog
&& vdev_is_dead(vd
))
893 valid
= vdev_log_state_valid(vd
);
894 spa_config_exit(os
->os_spa
, SCL_STATE
, FTAG
);
900 * Check whether the current uberblock is checkpointed (e.g.
901 * we are rewinding) and whether the current header has been
902 * claimed or not. If it hasn't then skip verifying it. We
903 * do this because its ZIL blocks may be part of the pool's
904 * state before the rewind, which is no longer valid.
906 zil_header_t
*zh
= zil_header_in_syncing_context(zilog
);
907 if (zilog
->zl_spa
->spa_uberblock
.ub_checkpoint_txg
!= 0 &&
908 zh
->zh_claim_txg
== 0)
913 * Because tx == NULL, zil_claim_log_block() will not actually claim
914 * any blocks, but just determine whether it is possible to do so.
915 * In addition to checking the log chain, zil_claim_log_block()
916 * will invoke zio_claim() with a done func of spa_claim_notify(),
917 * which will update spa_max_claim_txg. See spa_load() for details.
919 error
= zil_parse(zilog
, zil_claim_log_block
, zil_claim_log_record
, tx
,
920 zilog
->zl_header
->zh_claim_txg
? -1ULL :
921 spa_min_claim_txg(os
->os_spa
));
923 return ((error
== ECKSUM
|| error
== ENOENT
) ? 0 : error
);
927 * When an itx is "skipped", this function is used to properly mark the
928 * waiter as "done, and signal any thread(s) waiting on it. An itx can
929 * be skipped (and not committed to an lwb) for a variety of reasons,
930 * one of them being that the itx was committed via spa_sync(), prior to
931 * it being committed to an lwb; this can happen if a thread calling
932 * zil_commit() is racing with spa_sync().
935 zil_commit_waiter_skip(zil_commit_waiter_t
*zcw
)
937 mutex_enter(&zcw
->zcw_lock
);
938 ASSERT3B(zcw
->zcw_done
, ==, B_FALSE
);
939 zcw
->zcw_done
= B_TRUE
;
940 cv_broadcast(&zcw
->zcw_cv
);
941 mutex_exit(&zcw
->zcw_lock
);
945 * This function is used when the given waiter is to be linked into an
946 * lwb's "lwb_waiter" list; i.e. when the itx is committed to the lwb.
947 * At this point, the waiter will no longer be referenced by the itx,
948 * and instead, will be referenced by the lwb.
951 zil_commit_waiter_link_lwb(zil_commit_waiter_t
*zcw
, lwb_t
*lwb
)
954 * The lwb_waiters field of the lwb is protected by the zilog's
955 * zl_lock, thus it must be held when calling this function.
957 ASSERT(MUTEX_HELD(&lwb
->lwb_zilog
->zl_lock
));
959 mutex_enter(&zcw
->zcw_lock
);
960 ASSERT(!list_link_active(&zcw
->zcw_node
));
961 ASSERT3P(zcw
->zcw_lwb
, ==, NULL
);
962 ASSERT3P(lwb
, !=, NULL
);
963 ASSERT(lwb
->lwb_state
== LWB_STATE_OPENED
||
964 lwb
->lwb_state
== LWB_STATE_ISSUED
||
965 lwb
->lwb_state
== LWB_STATE_WRITE_DONE
);
967 list_insert_tail(&lwb
->lwb_waiters
, zcw
);
969 mutex_exit(&zcw
->zcw_lock
);
973 * This function is used when zio_alloc_zil() fails to allocate a ZIL
974 * block, and the given waiter must be linked to the "nolwb waiters"
975 * list inside of zil_process_commit_list().
978 zil_commit_waiter_link_nolwb(zil_commit_waiter_t
*zcw
, list_t
*nolwb
)
980 mutex_enter(&zcw
->zcw_lock
);
981 ASSERT(!list_link_active(&zcw
->zcw_node
));
982 ASSERT3P(zcw
->zcw_lwb
, ==, NULL
);
983 list_insert_tail(nolwb
, zcw
);
984 mutex_exit(&zcw
->zcw_lock
);
988 zil_lwb_add_block(lwb_t
*lwb
, const blkptr_t
*bp
)
990 avl_tree_t
*t
= &lwb
->lwb_vdev_tree
;
992 zil_vdev_node_t
*zv
, zvsearch
;
993 int ndvas
= BP_GET_NDVAS(bp
);
996 if (zil_nocacheflush
)
999 mutex_enter(&lwb
->lwb_vdev_lock
);
1000 for (i
= 0; i
< ndvas
; i
++) {
1001 zvsearch
.zv_vdev
= DVA_GET_VDEV(&bp
->blk_dva
[i
]);
1002 if (avl_find(t
, &zvsearch
, &where
) == NULL
) {
1003 zv
= kmem_alloc(sizeof (*zv
), KM_SLEEP
);
1004 zv
->zv_vdev
= zvsearch
.zv_vdev
;
1005 avl_insert(t
, zv
, where
);
1008 mutex_exit(&lwb
->lwb_vdev_lock
);
1012 zil_lwb_flush_defer(lwb_t
*lwb
, lwb_t
*nlwb
)
1014 avl_tree_t
*src
= &lwb
->lwb_vdev_tree
;
1015 avl_tree_t
*dst
= &nlwb
->lwb_vdev_tree
;
1016 void *cookie
= NULL
;
1017 zil_vdev_node_t
*zv
;
1019 ASSERT3S(lwb
->lwb_state
, ==, LWB_STATE_WRITE_DONE
);
1020 ASSERT3S(nlwb
->lwb_state
, !=, LWB_STATE_WRITE_DONE
);
1021 ASSERT3S(nlwb
->lwb_state
, !=, LWB_STATE_FLUSH_DONE
);
1024 * While 'lwb' is at a point in its lifetime where lwb_vdev_tree does
1025 * not need the protection of lwb_vdev_lock (it will only be modified
1026 * while holding zilog->zl_lock) as its writes and those of its
1027 * children have all completed. The younger 'nlwb' may be waiting on
1028 * future writes to additional vdevs.
1030 mutex_enter(&nlwb
->lwb_vdev_lock
);
1032 * Tear down the 'lwb' vdev tree, ensuring that entries which do not
1033 * exist in 'nlwb' are moved to it, freeing any would-be duplicates.
1035 while ((zv
= avl_destroy_nodes(src
, &cookie
)) != NULL
) {
1038 if (avl_find(dst
, zv
, &where
) == NULL
) {
1039 avl_insert(dst
, zv
, where
);
1041 kmem_free(zv
, sizeof (*zv
));
1044 mutex_exit(&nlwb
->lwb_vdev_lock
);
1048 zil_lwb_add_txg(lwb_t
*lwb
, uint64_t txg
)
1050 lwb
->lwb_max_txg
= MAX(lwb
->lwb_max_txg
, txg
);
1054 * This function is a called after all vdevs associated with a given lwb
1055 * write have completed their DKIOCFLUSHWRITECACHE command; or as soon
1056 * as the lwb write completes, if "zil_nocacheflush" is set. Further,
1057 * all "previous" lwb's will have completed before this function is
1058 * called; i.e. this function is called for all previous lwbs before
1059 * it's called for "this" lwb (enforced via zio the dependencies
1060 * configured in zil_lwb_set_zio_dependency()).
1062 * The intention is for this function to be called as soon as the
1063 * contents of an lwb are considered "stable" on disk, and will survive
1064 * any sudden loss of power. At this point, any threads waiting for the
1065 * lwb to reach this state are signalled, and the "waiter" structures
1066 * are marked "done".
1069 zil_lwb_flush_vdevs_done(zio_t
*zio
)
1071 lwb_t
*lwb
= zio
->io_private
;
1072 zilog_t
*zilog
= lwb
->lwb_zilog
;
1073 dmu_tx_t
*tx
= lwb
->lwb_tx
;
1074 zil_commit_waiter_t
*zcw
;
1076 spa_config_exit(zilog
->zl_spa
, SCL_STATE
, lwb
);
1078 zio_buf_free(lwb
->lwb_buf
, lwb
->lwb_sz
);
1080 mutex_enter(&zilog
->zl_lock
);
1083 * Ensure the lwb buffer pointer is cleared before releasing the
1084 * txg. If we have had an allocation failure and the txg is
1085 * waiting to sync then we want zil_sync() to remove the lwb so
1086 * that it's not picked up as the next new one in
1087 * zil_process_commit_list(). zil_sync() will only remove the
1088 * lwb if lwb_buf is null.
1090 lwb
->lwb_buf
= NULL
;
1093 ASSERT3U(lwb
->lwb_issued_timestamp
, >, 0);
1094 zilog
->zl_last_lwb_latency
= gethrtime() - lwb
->lwb_issued_timestamp
;
1096 lwb
->lwb_root_zio
= NULL
;
1098 ASSERT3S(lwb
->lwb_state
, ==, LWB_STATE_WRITE_DONE
);
1099 lwb
->lwb_state
= LWB_STATE_FLUSH_DONE
;
1101 if (zilog
->zl_last_lwb_opened
== lwb
) {
1103 * Remember the highest committed log sequence number
1104 * for ztest. We only update this value when all the log
1105 * writes succeeded, because ztest wants to ASSERT that
1106 * it got the whole log chain.
1108 zilog
->zl_commit_lr_seq
= zilog
->zl_lr_seq
;
1111 while ((zcw
= list_head(&lwb
->lwb_waiters
)) != NULL
) {
1112 mutex_enter(&zcw
->zcw_lock
);
1114 ASSERT(list_link_active(&zcw
->zcw_node
));
1115 list_remove(&lwb
->lwb_waiters
, zcw
);
1117 ASSERT3P(zcw
->zcw_lwb
, ==, lwb
);
1118 zcw
->zcw_lwb
= NULL
;
1120 zcw
->zcw_zio_error
= zio
->io_error
;
1122 ASSERT3B(zcw
->zcw_done
, ==, B_FALSE
);
1123 zcw
->zcw_done
= B_TRUE
;
1124 cv_broadcast(&zcw
->zcw_cv
);
1126 mutex_exit(&zcw
->zcw_lock
);
1129 mutex_exit(&zilog
->zl_lock
);
1132 * Now that we've written this log block, we have a stable pointer
1133 * to the next block in the chain, so it's OK to let the txg in
1134 * which we allocated the next block sync.
1140 * This is called when an lwb's write zio completes. The callback's
1141 * purpose is to issue the DKIOCFLUSHWRITECACHE commands for the vdevs
1142 * in the lwb's lwb_vdev_tree. The tree will contain the vdevs involved
1143 * in writing out this specific lwb's data, and in the case that cache
1144 * flushes have been deferred, vdevs involved in writing the data for
1145 * previous lwbs. The writes corresponding to all the vdevs in the
1146 * lwb_vdev_tree will have completed by the time this is called, due to
1147 * the zio dependencies configured in zil_lwb_set_zio_dependency(),
1148 * which takes deferred flushes into account. The lwb will be "done"
1149 * once zil_lwb_flush_vdevs_done() is called, which occurs in the zio
1150 * completion callback for the lwb's root zio.
1153 zil_lwb_write_done(zio_t
*zio
)
1155 lwb_t
*lwb
= zio
->io_private
;
1156 spa_t
*spa
= zio
->io_spa
;
1157 zilog_t
*zilog
= lwb
->lwb_zilog
;
1158 avl_tree_t
*t
= &lwb
->lwb_vdev_tree
;
1159 void *cookie
= NULL
;
1160 zil_vdev_node_t
*zv
;
1163 ASSERT3S(spa_config_held(spa
, SCL_STATE
, RW_READER
), !=, 0);
1165 ASSERT(BP_GET_COMPRESS(zio
->io_bp
) == ZIO_COMPRESS_OFF
);
1166 ASSERT(BP_GET_TYPE(zio
->io_bp
) == DMU_OT_INTENT_LOG
);
1167 ASSERT(BP_GET_LEVEL(zio
->io_bp
) == 0);
1168 ASSERT(BP_GET_BYTEORDER(zio
->io_bp
) == ZFS_HOST_BYTEORDER
);
1169 ASSERT(!BP_IS_GANG(zio
->io_bp
));
1170 ASSERT(!BP_IS_HOLE(zio
->io_bp
));
1171 ASSERT(BP_GET_FILL(zio
->io_bp
) == 0);
1173 abd_put(zio
->io_abd
);
1175 mutex_enter(&zilog
->zl_lock
);
1176 ASSERT3S(lwb
->lwb_state
, ==, LWB_STATE_ISSUED
);
1177 lwb
->lwb_state
= LWB_STATE_WRITE_DONE
;
1178 lwb
->lwb_write_zio
= NULL
;
1179 nlwb
= list_next(&zilog
->zl_lwb_list
, lwb
);
1180 mutex_exit(&zilog
->zl_lock
);
1182 if (avl_numnodes(t
) == 0)
1186 * If there was an IO error, we're not going to call zio_flush()
1187 * on these vdevs, so we simply empty the tree and free the
1188 * nodes. We avoid calling zio_flush() since there isn't any
1189 * good reason for doing so, after the lwb block failed to be
1192 if (zio
->io_error
!= 0) {
1193 while ((zv
= avl_destroy_nodes(t
, &cookie
)) != NULL
)
1194 kmem_free(zv
, sizeof (*zv
));
1199 * If this lwb does not have any threads waiting for it to
1200 * complete, we want to defer issuing the DKIOCFLUSHWRITECACHE
1201 * command to the vdevs written to by "this" lwb, and instead
1202 * rely on the "next" lwb to handle the DKIOCFLUSHWRITECACHE
1203 * command for those vdevs. Thus, we merge the vdev tree of
1204 * "this" lwb with the vdev tree of the "next" lwb in the list,
1205 * and assume the "next" lwb will handle flushing the vdevs (or
1206 * deferring the flush(s) again).
1208 * This is a useful performance optimization, especially for
1209 * workloads with lots of async write activity and few sync
1210 * write and/or fsync activity, as it has the potential to
1211 * coalesce multiple flush commands to a vdev into one.
1213 if (list_head(&lwb
->lwb_waiters
) == NULL
&& nlwb
!= NULL
) {
1214 zil_lwb_flush_defer(lwb
, nlwb
);
1215 ASSERT(avl_is_empty(&lwb
->lwb_vdev_tree
));
1219 while ((zv
= avl_destroy_nodes(t
, &cookie
)) != NULL
) {
1220 vdev_t
*vd
= vdev_lookup_top(spa
, zv
->zv_vdev
);
1222 zio_flush(lwb
->lwb_root_zio
, vd
);
1223 kmem_free(zv
, sizeof (*zv
));
1228 zil_lwb_set_zio_dependency(zilog_t
*zilog
, lwb_t
*lwb
)
1230 lwb_t
*last_lwb_opened
= zilog
->zl_last_lwb_opened
;
1232 ASSERT(MUTEX_HELD(&zilog
->zl_issuer_lock
));
1233 ASSERT(MUTEX_HELD(&zilog
->zl_lock
));
1236 * The zilog's "zl_last_lwb_opened" field is used to build the
1237 * lwb/zio dependency chain, which is used to preserve the
1238 * ordering of lwb completions that is required by the semantics
1239 * of the ZIL. Each new lwb zio becomes a parent of the
1240 * "previous" lwb zio, such that the new lwb's zio cannot
1241 * complete until the "previous" lwb's zio completes.
1243 * This is required by the semantics of zil_commit(); the commit
1244 * waiters attached to the lwbs will be woken in the lwb zio's
1245 * completion callback, so this zio dependency graph ensures the
1246 * waiters are woken in the correct order (the same order the
1247 * lwbs were created).
1249 if (last_lwb_opened
!= NULL
&&
1250 last_lwb_opened
->lwb_state
!= LWB_STATE_FLUSH_DONE
) {
1251 ASSERT(last_lwb_opened
->lwb_state
== LWB_STATE_OPENED
||
1252 last_lwb_opened
->lwb_state
== LWB_STATE_ISSUED
||
1253 last_lwb_opened
->lwb_state
== LWB_STATE_WRITE_DONE
);
1255 ASSERT3P(last_lwb_opened
->lwb_root_zio
, !=, NULL
);
1256 zio_add_child(lwb
->lwb_root_zio
,
1257 last_lwb_opened
->lwb_root_zio
);
1260 * If the previous lwb's write hasn't already completed,
1261 * we also want to order the completion of the lwb write
1262 * zios (above, we only order the completion of the lwb
1263 * root zios). This is required because of how we can
1264 * defer the DKIOCFLUSHWRITECACHE commands for each lwb.
1266 * When the DKIOCFLUSHWRITECACHE commands are defered,
1267 * the previous lwb will rely on this lwb to flush the
1268 * vdevs written to by that previous lwb. Thus, we need
1269 * to ensure this lwb doesn't issue the flush until
1270 * after the previous lwb's write completes. We ensure
1271 * this ordering by setting the zio parent/child
1272 * relationship here.
1274 * Without this relationship on the lwb's write zio,
1275 * it's possible for this lwb's write to complete prior
1276 * to the previous lwb's write completing; and thus, the
1277 * vdevs for the previous lwb would be flushed prior to
1278 * that lwb's data being written to those vdevs (the
1279 * vdevs are flushed in the lwb write zio's completion
1280 * handler, zil_lwb_write_done()).
1282 if (last_lwb_opened
->lwb_state
!= LWB_STATE_WRITE_DONE
) {
1283 ASSERT(last_lwb_opened
->lwb_state
== LWB_STATE_OPENED
||
1284 last_lwb_opened
->lwb_state
== LWB_STATE_ISSUED
);
1286 ASSERT3P(last_lwb_opened
->lwb_write_zio
, !=, NULL
);
1287 zio_add_child(lwb
->lwb_write_zio
,
1288 last_lwb_opened
->lwb_write_zio
);
1295 * This function's purpose is to "open" an lwb such that it is ready to
1296 * accept new itxs being committed to it. To do this, the lwb's zio
1297 * structures are created, and linked to the lwb. This function is
1298 * idempotent; if the passed in lwb has already been opened, this
1299 * function is essentially a no-op.
1302 zil_lwb_write_open(zilog_t
*zilog
, lwb_t
*lwb
)
1304 zbookmark_phys_t zb
;
1305 zio_priority_t prio
;
1307 ASSERT(MUTEX_HELD(&zilog
->zl_issuer_lock
));
1308 ASSERT3P(lwb
, !=, NULL
);
1309 EQUIV(lwb
->lwb_root_zio
== NULL
, lwb
->lwb_state
== LWB_STATE_CLOSED
);
1310 EQUIV(lwb
->lwb_root_zio
!= NULL
, lwb
->lwb_state
== LWB_STATE_OPENED
);
1312 SET_BOOKMARK(&zb
, lwb
->lwb_blk
.blk_cksum
.zc_word
[ZIL_ZC_OBJSET
],
1313 ZB_ZIL_OBJECT
, ZB_ZIL_LEVEL
,
1314 lwb
->lwb_blk
.blk_cksum
.zc_word
[ZIL_ZC_SEQ
]);
1316 if (lwb
->lwb_root_zio
== NULL
) {
1317 abd_t
*lwb_abd
= abd_get_from_buf(lwb
->lwb_buf
,
1318 BP_GET_LSIZE(&lwb
->lwb_blk
));
1320 if (!lwb
->lwb_slog
|| zilog
->zl_cur_used
<= zil_slog_bulk
)
1321 prio
= ZIO_PRIORITY_SYNC_WRITE
;
1323 prio
= ZIO_PRIORITY_ASYNC_WRITE
;
1325 lwb
->lwb_root_zio
= zio_root(zilog
->zl_spa
,
1326 zil_lwb_flush_vdevs_done
, lwb
, ZIO_FLAG_CANFAIL
);
1327 ASSERT3P(lwb
->lwb_root_zio
, !=, NULL
);
1329 lwb
->lwb_write_zio
= zio_rewrite(lwb
->lwb_root_zio
,
1330 zilog
->zl_spa
, 0, &lwb
->lwb_blk
, lwb_abd
,
1331 BP_GET_LSIZE(&lwb
->lwb_blk
), zil_lwb_write_done
, lwb
,
1332 prio
, ZIO_FLAG_CANFAIL
| ZIO_FLAG_DONT_PROPAGATE
, &zb
);
1333 ASSERT3P(lwb
->lwb_write_zio
, !=, NULL
);
1335 lwb
->lwb_state
= LWB_STATE_OPENED
;
1337 mutex_enter(&zilog
->zl_lock
);
1338 zil_lwb_set_zio_dependency(zilog
, lwb
);
1339 zilog
->zl_last_lwb_opened
= lwb
;
1340 mutex_exit(&zilog
->zl_lock
);
1343 ASSERT3P(lwb
->lwb_root_zio
, !=, NULL
);
1344 ASSERT3P(lwb
->lwb_write_zio
, !=, NULL
);
1345 ASSERT3S(lwb
->lwb_state
, ==, LWB_STATE_OPENED
);
1349 * Define a limited set of intent log block sizes.
1351 * These must be a multiple of 4KB. Note only the amount used (again
1352 * aligned to 4KB) actually gets written. However, we can't always just
1353 * allocate SPA_OLD_MAXBLOCKSIZE as the slog space could be exhausted.
1355 uint64_t zil_block_buckets
[] = {
1356 4096, /* non TX_WRITE */
1357 8192+4096, /* data base */
1358 32*1024 + 4096, /* NFS writes */
1363 * Start a log block write and advance to the next log block.
1364 * Calls are serialized.
1367 zil_lwb_write_issue(zilog_t
*zilog
, lwb_t
*lwb
)
1371 spa_t
*spa
= zilog
->zl_spa
;
1375 uint64_t zil_blksz
, wsz
;
1379 ASSERT(MUTEX_HELD(&zilog
->zl_issuer_lock
));
1380 ASSERT3P(lwb
->lwb_root_zio
, !=, NULL
);
1381 ASSERT3P(lwb
->lwb_write_zio
, !=, NULL
);
1382 ASSERT3S(lwb
->lwb_state
, ==, LWB_STATE_OPENED
);
1384 if (BP_GET_CHECKSUM(&lwb
->lwb_blk
) == ZIO_CHECKSUM_ZILOG2
) {
1385 zilc
= (zil_chain_t
*)lwb
->lwb_buf
;
1386 bp
= &zilc
->zc_next_blk
;
1388 zilc
= (zil_chain_t
*)(lwb
->lwb_buf
+ lwb
->lwb_sz
);
1389 bp
= &zilc
->zc_next_blk
;
1392 ASSERT(lwb
->lwb_nused
<= lwb
->lwb_sz
);
1395 * Allocate the next block and save its address in this block
1396 * before writing it in order to establish the log chain.
1397 * Note that if the allocation of nlwb synced before we wrote
1398 * the block that points at it (lwb), we'd leak it if we crashed.
1399 * Therefore, we don't do dmu_tx_commit() until zil_lwb_write_done().
1400 * We dirty the dataset to ensure that zil_sync() will be called
1401 * to clean up in the event of allocation failure or I/O failure.
1404 tx
= dmu_tx_create(zilog
->zl_os
);
1407 * Since we are not going to create any new dirty data, and we
1408 * can even help with clearing the existing dirty data, we
1409 * should not be subject to the dirty data based delays. We
1410 * use TXG_NOTHROTTLE to bypass the delay mechanism.
1412 VERIFY0(dmu_tx_assign(tx
, TXG_WAIT
| TXG_NOTHROTTLE
));
1414 dsl_dataset_dirty(dmu_objset_ds(zilog
->zl_os
), tx
);
1415 txg
= dmu_tx_get_txg(tx
);
1420 * Log blocks are pre-allocated. Here we select the size of the next
1421 * block, based on size used in the last block.
1422 * - first find the smallest bucket that will fit the block from a
1423 * limited set of block sizes. This is because it's faster to write
1424 * blocks allocated from the same metaslab as they are adjacent or
1426 * - next find the maximum from the new suggested size and an array of
1427 * previous sizes. This lessens a picket fence effect of wrongly
1428 * guesssing the size if we have a stream of say 2k, 64k, 2k, 64k
1431 * Note we only write what is used, but we can't just allocate
1432 * the maximum block size because we can exhaust the available
1435 zil_blksz
= zilog
->zl_cur_used
+ sizeof (zil_chain_t
);
1436 for (i
= 0; zil_blksz
> zil_block_buckets
[i
]; i
++)
1438 zil_blksz
= zil_block_buckets
[i
];
1439 if (zil_blksz
== UINT64_MAX
)
1440 zil_blksz
= SPA_OLD_MAXBLOCKSIZE
;
1441 zilog
->zl_prev_blks
[zilog
->zl_prev_rotor
] = zil_blksz
;
1442 for (i
= 0; i
< ZIL_PREV_BLKS
; i
++)
1443 zil_blksz
= MAX(zil_blksz
, zilog
->zl_prev_blks
[i
]);
1444 zilog
->zl_prev_rotor
= (zilog
->zl_prev_rotor
+ 1) & (ZIL_PREV_BLKS
- 1);
1448 /* pass the old blkptr in order to spread log blocks across devs */
1449 error
= zio_alloc_zil(spa
, zilog
->zl_os
->os_dsl_dataset
->ds_object
,
1450 txg
, bp
, &lwb
->lwb_blk
, zil_blksz
, &slog
);
1452 ASSERT3U(bp
->blk_birth
, ==, txg
);
1453 bp
->blk_cksum
= lwb
->lwb_blk
.blk_cksum
;
1454 bp
->blk_cksum
.zc_word
[ZIL_ZC_SEQ
]++;
1457 * Allocate a new log write block (lwb).
1459 nlwb
= zil_alloc_lwb(zilog
, bp
, slog
, txg
);
1462 if (BP_GET_CHECKSUM(&lwb
->lwb_blk
) == ZIO_CHECKSUM_ZILOG2
) {
1463 /* For Slim ZIL only write what is used. */
1464 wsz
= P2ROUNDUP_TYPED(lwb
->lwb_nused
, ZIL_MIN_BLKSZ
, uint64_t);
1465 ASSERT3U(wsz
, <=, lwb
->lwb_sz
);
1466 zio_shrink(lwb
->lwb_write_zio
, wsz
);
1473 zilc
->zc_nused
= lwb
->lwb_nused
;
1474 zilc
->zc_eck
.zec_cksum
= lwb
->lwb_blk
.blk_cksum
;
1477 * clear unused data for security
1479 bzero(lwb
->lwb_buf
+ lwb
->lwb_nused
, wsz
- lwb
->lwb_nused
);
1481 spa_config_enter(zilog
->zl_spa
, SCL_STATE
, lwb
, RW_READER
);
1483 zil_lwb_add_block(lwb
, &lwb
->lwb_blk
);
1484 lwb
->lwb_issued_timestamp
= gethrtime();
1485 lwb
->lwb_state
= LWB_STATE_ISSUED
;
1487 zio_nowait(lwb
->lwb_root_zio
);
1488 zio_nowait(lwb
->lwb_write_zio
);
1491 * If there was an allocation failure then nlwb will be null which
1492 * forces a txg_wait_synced().
1498 zil_lwb_commit(zilog_t
*zilog
, itx_t
*itx
, lwb_t
*lwb
)
1501 lr_write_t
*lrwb
, *lrw
;
1503 uint64_t dlen
, dnow
, lwb_sp
, reclen
, txg
;
1505 ASSERT(MUTEX_HELD(&zilog
->zl_issuer_lock
));
1506 ASSERT3P(lwb
, !=, NULL
);
1507 ASSERT3P(lwb
->lwb_buf
, !=, NULL
);
1509 zil_lwb_write_open(zilog
, lwb
);
1512 lrw
= (lr_write_t
*)lrc
;
1515 * A commit itx doesn't represent any on-disk state; instead
1516 * it's simply used as a place holder on the commit list, and
1517 * provides a mechanism for attaching a "commit waiter" onto the
1518 * correct lwb (such that the waiter can be signalled upon
1519 * completion of that lwb). Thus, we don't process this itx's
1520 * log record if it's a commit itx (these itx's don't have log
1521 * records), and instead link the itx's waiter onto the lwb's
1524 * For more details, see the comment above zil_commit().
1526 if (lrc
->lrc_txtype
== TX_COMMIT
) {
1527 mutex_enter(&zilog
->zl_lock
);
1528 zil_commit_waiter_link_lwb(itx
->itx_private
, lwb
);
1529 itx
->itx_private
= NULL
;
1530 mutex_exit(&zilog
->zl_lock
);
1534 if (lrc
->lrc_txtype
== TX_WRITE
&& itx
->itx_wr_state
== WR_NEED_COPY
) {
1535 dlen
= P2ROUNDUP_TYPED(
1536 lrw
->lr_length
, sizeof (uint64_t), uint64_t);
1540 reclen
= lrc
->lrc_reclen
;
1541 zilog
->zl_cur_used
+= (reclen
+ dlen
);
1544 ASSERT3U(zilog
->zl_cur_used
, <, UINT64_MAX
- (reclen
+ dlen
));
1548 * If this record won't fit in the current log block, start a new one.
1549 * For WR_NEED_COPY optimize layout for minimal number of chunks.
1551 lwb_sp
= lwb
->lwb_sz
- lwb
->lwb_nused
;
1552 if (reclen
> lwb_sp
|| (reclen
+ dlen
> lwb_sp
&&
1553 lwb_sp
< ZIL_MAX_WASTE_SPACE
&& (dlen
% ZIL_MAX_LOG_DATA
== 0 ||
1554 lwb_sp
< reclen
+ dlen
% ZIL_MAX_LOG_DATA
))) {
1555 lwb
= zil_lwb_write_issue(zilog
, lwb
);
1558 zil_lwb_write_open(zilog
, lwb
);
1559 ASSERT(LWB_EMPTY(lwb
));
1560 lwb_sp
= lwb
->lwb_sz
- lwb
->lwb_nused
;
1561 ASSERT3U(reclen
+ MIN(dlen
, sizeof (uint64_t)), <=, lwb_sp
);
1564 dnow
= MIN(dlen
, lwb_sp
- reclen
);
1565 lr_buf
= lwb
->lwb_buf
+ lwb
->lwb_nused
;
1566 bcopy(lrc
, lr_buf
, reclen
);
1567 lrcb
= (lr_t
*)lr_buf
; /* Like lrc, but inside lwb. */
1568 lrwb
= (lr_write_t
*)lrcb
; /* Like lrw, but inside lwb. */
1571 * If it's a write, fetch the data or get its blkptr as appropriate.
1573 if (lrc
->lrc_txtype
== TX_WRITE
) {
1574 if (txg
> spa_freeze_txg(zilog
->zl_spa
))
1575 txg_wait_synced(zilog
->zl_dmu_pool
, txg
);
1576 if (itx
->itx_wr_state
!= WR_COPIED
) {
1580 if (itx
->itx_wr_state
== WR_NEED_COPY
) {
1581 dbuf
= lr_buf
+ reclen
;
1582 lrcb
->lrc_reclen
+= dnow
;
1583 if (lrwb
->lr_length
> dnow
)
1584 lrwb
->lr_length
= dnow
;
1585 lrw
->lr_offset
+= dnow
;
1586 lrw
->lr_length
-= dnow
;
1588 ASSERT(itx
->itx_wr_state
== WR_INDIRECT
);
1593 * We pass in the "lwb_write_zio" rather than
1594 * "lwb_root_zio" so that the "lwb_write_zio"
1595 * becomes the parent of any zio's created by
1596 * the "zl_get_data" callback. The vdevs are
1597 * flushed after the "lwb_write_zio" completes,
1598 * so we want to make sure that completion
1599 * callback waits for these additional zio's,
1600 * such that the vdevs used by those zio's will
1601 * be included in the lwb's vdev tree, and those
1602 * vdevs will be properly flushed. If we passed
1603 * in "lwb_root_zio" here, then these additional
1604 * vdevs may not be flushed; e.g. if these zio's
1605 * completed after "lwb_write_zio" completed.
1607 error
= zilog
->zl_get_data(itx
->itx_private
,
1608 lrwb
, dbuf
, lwb
, lwb
->lwb_write_zio
);
1611 txg_wait_synced(zilog
->zl_dmu_pool
, txg
);
1615 ASSERT(error
== ENOENT
|| error
== EEXIST
||
1623 * We're actually making an entry, so update lrc_seq to be the
1624 * log record sequence number. Note that this is generally not
1625 * equal to the itx sequence number because not all transactions
1626 * are synchronous, and sometimes spa_sync() gets there first.
1628 lrcb
->lrc_seq
= ++zilog
->zl_lr_seq
;
1629 lwb
->lwb_nused
+= reclen
+ dnow
;
1631 zil_lwb_add_txg(lwb
, txg
);
1633 ASSERT3U(lwb
->lwb_nused
, <=, lwb
->lwb_sz
);
1634 ASSERT0(P2PHASE(lwb
->lwb_nused
, sizeof (uint64_t)));
1638 zilog
->zl_cur_used
+= reclen
;
1646 zil_itx_create(uint64_t txtype
, size_t lrsize
)
1650 lrsize
= P2ROUNDUP_TYPED(lrsize
, sizeof (uint64_t), size_t);
1652 itx
= kmem_alloc(offsetof(itx_t
, itx_lr
) + lrsize
, KM_SLEEP
);
1653 itx
->itx_lr
.lrc_txtype
= txtype
;
1654 itx
->itx_lr
.lrc_reclen
= lrsize
;
1655 itx
->itx_lr
.lrc_seq
= 0; /* defensive */
1656 itx
->itx_sync
= B_TRUE
; /* default is synchronous */
1662 zil_itx_destroy(itx_t
*itx
)
1664 kmem_free(itx
, offsetof(itx_t
, itx_lr
) + itx
->itx_lr
.lrc_reclen
);
1668 * Free up the sync and async itxs. The itxs_t has already been detached
1669 * so no locks are needed.
1672 zil_itxg_clean(itxs_t
*itxs
)
1678 itx_async_node_t
*ian
;
1680 list
= &itxs
->i_sync_list
;
1681 while ((itx
= list_head(list
)) != NULL
) {
1683 * In the general case, commit itxs will not be found
1684 * here, as they'll be committed to an lwb via
1685 * zil_lwb_commit(), and free'd in that function. Having
1686 * said that, it is still possible for commit itxs to be
1687 * found here, due to the following race:
1689 * - a thread calls zil_commit() which assigns the
1690 * commit itx to a per-txg i_sync_list
1691 * - zil_itxg_clean() is called (e.g. via spa_sync())
1692 * while the waiter is still on the i_sync_list
1694 * There's nothing to prevent syncing the txg while the
1695 * waiter is on the i_sync_list. This normally doesn't
1696 * happen because spa_sync() is slower than zil_commit(),
1697 * but if zil_commit() calls txg_wait_synced() (e.g.
1698 * because zil_create() or zil_commit_writer_stall() is
1699 * called) we will hit this case.
1701 if (itx
->itx_lr
.lrc_txtype
== TX_COMMIT
)
1702 zil_commit_waiter_skip(itx
->itx_private
);
1704 list_remove(list
, itx
);
1705 zil_itx_destroy(itx
);
1709 t
= &itxs
->i_async_tree
;
1710 while ((ian
= avl_destroy_nodes(t
, &cookie
)) != NULL
) {
1711 list
= &ian
->ia_list
;
1712 while ((itx
= list_head(list
)) != NULL
) {
1713 list_remove(list
, itx
);
1714 /* commit itxs should never be on the async lists. */
1715 ASSERT3U(itx
->itx_lr
.lrc_txtype
, !=, TX_COMMIT
);
1716 zil_itx_destroy(itx
);
1719 kmem_free(ian
, sizeof (itx_async_node_t
));
1723 kmem_free(itxs
, sizeof (itxs_t
));
1727 zil_aitx_compare(const void *x1
, const void *x2
)
1729 const uint64_t o1
= ((itx_async_node_t
*)x1
)->ia_foid
;
1730 const uint64_t o2
= ((itx_async_node_t
*)x2
)->ia_foid
;
1741 * Remove all async itx with the given oid.
1744 zil_remove_async(zilog_t
*zilog
, uint64_t oid
)
1747 itx_async_node_t
*ian
;
1754 list_create(&clean_list
, sizeof (itx_t
), offsetof(itx_t
, itx_node
));
1756 if (spa_freeze_txg(zilog
->zl_spa
) != UINT64_MAX
) /* ziltest support */
1759 otxg
= spa_last_synced_txg(zilog
->zl_spa
) + 1;
1761 for (txg
= otxg
; txg
< (otxg
+ TXG_CONCURRENT_STATES
); txg
++) {
1762 itxg_t
*itxg
= &zilog
->zl_itxg
[txg
& TXG_MASK
];
1764 mutex_enter(&itxg
->itxg_lock
);
1765 if (itxg
->itxg_txg
!= txg
) {
1766 mutex_exit(&itxg
->itxg_lock
);
1771 * Locate the object node and append its list.
1773 t
= &itxg
->itxg_itxs
->i_async_tree
;
1774 ian
= avl_find(t
, &oid
, &where
);
1776 list_move_tail(&clean_list
, &ian
->ia_list
);
1777 mutex_exit(&itxg
->itxg_lock
);
1779 while ((itx
= list_head(&clean_list
)) != NULL
) {
1780 list_remove(&clean_list
, itx
);
1781 /* commit itxs should never be on the async lists. */
1782 ASSERT3U(itx
->itx_lr
.lrc_txtype
, !=, TX_COMMIT
);
1783 zil_itx_destroy(itx
);
1785 list_destroy(&clean_list
);
1789 zil_itx_assign(zilog_t
*zilog
, itx_t
*itx
, dmu_tx_t
*tx
)
1793 itxs_t
*itxs
, *clean
= NULL
;
1796 * Object ids can be re-instantiated in the next txg so
1797 * remove any async transactions to avoid future leaks.
1798 * This can happen if a fsync occurs on the re-instantiated
1799 * object for a WR_INDIRECT or WR_NEED_COPY write, which gets
1800 * the new file data and flushes a write record for the old object.
1802 if ((itx
->itx_lr
.lrc_txtype
& ~TX_CI
) == TX_REMOVE
)
1803 zil_remove_async(zilog
, itx
->itx_oid
);
1806 * Ensure the data of a renamed file is committed before the rename.
1808 if ((itx
->itx_lr
.lrc_txtype
& ~TX_CI
) == TX_RENAME
)
1809 zil_async_to_sync(zilog
, itx
->itx_oid
);
1811 if (spa_freeze_txg(zilog
->zl_spa
) != UINT64_MAX
)
1814 txg
= dmu_tx_get_txg(tx
);
1816 itxg
= &zilog
->zl_itxg
[txg
& TXG_MASK
];
1817 mutex_enter(&itxg
->itxg_lock
);
1818 itxs
= itxg
->itxg_itxs
;
1819 if (itxg
->itxg_txg
!= txg
) {
1822 * The zil_clean callback hasn't got around to cleaning
1823 * this itxg. Save the itxs for release below.
1824 * This should be rare.
1826 zfs_dbgmsg("zil_itx_assign: missed itx cleanup for "
1827 "txg %llu", itxg
->itxg_txg
);
1828 clean
= itxg
->itxg_itxs
;
1830 itxg
->itxg_txg
= txg
;
1831 itxs
= itxg
->itxg_itxs
= kmem_zalloc(sizeof (itxs_t
), KM_SLEEP
);
1833 list_create(&itxs
->i_sync_list
, sizeof (itx_t
),
1834 offsetof(itx_t
, itx_node
));
1835 avl_create(&itxs
->i_async_tree
, zil_aitx_compare
,
1836 sizeof (itx_async_node_t
),
1837 offsetof(itx_async_node_t
, ia_node
));
1839 if (itx
->itx_sync
) {
1840 list_insert_tail(&itxs
->i_sync_list
, itx
);
1842 avl_tree_t
*t
= &itxs
->i_async_tree
;
1843 uint64_t foid
= ((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
) == 0)
1910 zil_itxg_clean(clean_me
);
1914 * This function will traverse the queue of itxs that need to be
1915 * committed, and move them onto the ZIL's zl_itx_commit_list.
1918 zil_get_commit_list(zilog_t
*zilog
)
1921 list_t
*commit_list
= &zilog
->zl_itx_commit_list
;
1923 ASSERT(MUTEX_HELD(&zilog
->zl_issuer_lock
));
1925 if (spa_freeze_txg(zilog
->zl_spa
) != UINT64_MAX
) /* ziltest support */
1928 otxg
= spa_last_synced_txg(zilog
->zl_spa
) + 1;
1931 * This is inherently racy, since there is nothing to prevent
1932 * the last synced txg from changing. That's okay since we'll
1933 * only commit things in the future.
1935 for (txg
= otxg
; txg
< (otxg
+ TXG_CONCURRENT_STATES
); txg
++) {
1936 itxg_t
*itxg
= &zilog
->zl_itxg
[txg
& TXG_MASK
];
1938 mutex_enter(&itxg
->itxg_lock
);
1939 if (itxg
->itxg_txg
!= txg
) {
1940 mutex_exit(&itxg
->itxg_lock
);
1945 * If we're adding itx records to the zl_itx_commit_list,
1946 * then the zil better be dirty in this "txg". We can assert
1947 * that here since we're holding the itxg_lock which will
1948 * prevent spa_sync from cleaning it. Once we add the itxs
1949 * to the zl_itx_commit_list we must commit it to disk even
1950 * if it's unnecessary (i.e. the txg was synced).
1952 ASSERT(zilog_is_dirty_in_txg(zilog
, txg
) ||
1953 spa_freeze_txg(zilog
->zl_spa
) != UINT64_MAX
);
1954 list_move_tail(commit_list
, &itxg
->itxg_itxs
->i_sync_list
);
1956 mutex_exit(&itxg
->itxg_lock
);
1961 * Move the async itxs for a specified object to commit into sync lists.
1964 zil_async_to_sync(zilog_t
*zilog
, uint64_t foid
)
1967 itx_async_node_t
*ian
;
1971 if (spa_freeze_txg(zilog
->zl_spa
) != UINT64_MAX
) /* ziltest support */
1974 otxg
= spa_last_synced_txg(zilog
->zl_spa
) + 1;
1977 * This is inherently racy, since there is nothing to prevent
1978 * the last synced txg from changing.
1980 for (txg
= otxg
; txg
< (otxg
+ TXG_CONCURRENT_STATES
); txg
++) {
1981 itxg_t
*itxg
= &zilog
->zl_itxg
[txg
& TXG_MASK
];
1983 mutex_enter(&itxg
->itxg_lock
);
1984 if (itxg
->itxg_txg
!= txg
) {
1985 mutex_exit(&itxg
->itxg_lock
);
1990 * If a foid is specified then find that node and append its
1991 * list. Otherwise walk the tree appending all the lists
1992 * to the sync list. We add to the end rather than the
1993 * beginning to ensure the create has happened.
1995 t
= &itxg
->itxg_itxs
->i_async_tree
;
1997 ian
= avl_find(t
, &foid
, &where
);
1999 list_move_tail(&itxg
->itxg_itxs
->i_sync_list
,
2003 void *cookie
= NULL
;
2005 while ((ian
= avl_destroy_nodes(t
, &cookie
)) != NULL
) {
2006 list_move_tail(&itxg
->itxg_itxs
->i_sync_list
,
2008 list_destroy(&ian
->ia_list
);
2009 kmem_free(ian
, sizeof (itx_async_node_t
));
2012 mutex_exit(&itxg
->itxg_lock
);
2017 * This function will prune commit itxs that are at the head of the
2018 * commit list (it won't prune past the first non-commit itx), and
2019 * either: a) attach them to the last lwb that's still pending
2020 * completion, or b) skip them altogether.
2022 * This is used as a performance optimization to prevent commit itxs
2023 * from generating new lwbs when it's unnecessary to do so.
2026 zil_prune_commit_list(zilog_t
*zilog
)
2030 ASSERT(MUTEX_HELD(&zilog
->zl_issuer_lock
));
2032 while (itx
= list_head(&zilog
->zl_itx_commit_list
)) {
2033 lr_t
*lrc
= &itx
->itx_lr
;
2034 if (lrc
->lrc_txtype
!= TX_COMMIT
)
2037 mutex_enter(&zilog
->zl_lock
);
2039 lwb_t
*last_lwb
= zilog
->zl_last_lwb_opened
;
2040 if (last_lwb
== NULL
||
2041 last_lwb
->lwb_state
== LWB_STATE_FLUSH_DONE
) {
2043 * All of the itxs this waiter was waiting on
2044 * must have already completed (or there were
2045 * never any itx's for it to wait on), so it's
2046 * safe to skip this waiter and mark it done.
2048 zil_commit_waiter_skip(itx
->itx_private
);
2050 zil_commit_waiter_link_lwb(itx
->itx_private
, last_lwb
);
2051 itx
->itx_private
= NULL
;
2054 mutex_exit(&zilog
->zl_lock
);
2056 list_remove(&zilog
->zl_itx_commit_list
, itx
);
2057 zil_itx_destroy(itx
);
2060 IMPLY(itx
!= NULL
, itx
->itx_lr
.lrc_txtype
!= TX_COMMIT
);
2064 zil_commit_writer_stall(zilog_t
*zilog
)
2067 * When zio_alloc_zil() fails to allocate the next lwb block on
2068 * disk, we must call txg_wait_synced() to ensure all of the
2069 * lwbs in the zilog's zl_lwb_list are synced and then freed (in
2070 * zil_sync()), such that any subsequent ZIL writer (i.e. a call
2071 * to zil_process_commit_list()) will have to call zil_create(),
2072 * and start a new ZIL chain.
2074 * Since zil_alloc_zil() failed, the lwb that was previously
2075 * issued does not have a pointer to the "next" lwb on disk.
2076 * Thus, if another ZIL writer thread was to allocate the "next"
2077 * on-disk lwb, that block could be leaked in the event of a
2078 * crash (because the previous lwb on-disk would not point to
2081 * We must hold the zilog's zl_issuer_lock while we do this, to
2082 * ensure no new threads enter zil_process_commit_list() until
2083 * all lwb's in the zl_lwb_list have been synced and freed
2084 * (which is achieved via the txg_wait_synced() call).
2086 ASSERT(MUTEX_HELD(&zilog
->zl_issuer_lock
));
2087 txg_wait_synced(zilog
->zl_dmu_pool
, 0);
2088 ASSERT3P(list_tail(&zilog
->zl_lwb_list
), ==, NULL
);
2092 * This function will traverse the commit list, creating new lwbs as
2093 * needed, and committing the itxs from the commit list to these newly
2094 * created lwbs. Additionally, as a new lwb is created, the previous
2095 * lwb will be issued to the zio layer to be written to disk.
2098 zil_process_commit_list(zilog_t
*zilog
)
2100 spa_t
*spa
= zilog
->zl_spa
;
2101 list_t nolwb_waiters
;
2105 ASSERT(MUTEX_HELD(&zilog
->zl_issuer_lock
));
2108 * Return if there's nothing to commit before we dirty the fs by
2109 * calling zil_create().
2111 if (list_head(&zilog
->zl_itx_commit_list
) == NULL
)
2114 list_create(&nolwb_waiters
, sizeof (zil_commit_waiter_t
),
2115 offsetof(zil_commit_waiter_t
, zcw_node
));
2117 lwb
= list_tail(&zilog
->zl_lwb_list
);
2119 lwb
= zil_create(zilog
);
2121 ASSERT3S(lwb
->lwb_state
, !=, LWB_STATE_ISSUED
);
2122 ASSERT3S(lwb
->lwb_state
, !=, LWB_STATE_WRITE_DONE
);
2123 ASSERT3S(lwb
->lwb_state
, !=, LWB_STATE_FLUSH_DONE
);
2126 while (itx
= list_head(&zilog
->zl_itx_commit_list
)) {
2127 lr_t
*lrc
= &itx
->itx_lr
;
2128 uint64_t txg
= lrc
->lrc_txg
;
2130 ASSERT3U(txg
, !=, 0);
2132 if (lrc
->lrc_txtype
== TX_COMMIT
) {
2133 DTRACE_PROBE2(zil__process__commit__itx
,
2134 zilog_t
*, zilog
, itx_t
*, itx
);
2136 DTRACE_PROBE2(zil__process__normal__itx
,
2137 zilog_t
*, zilog
, itx_t
*, itx
);
2140 boolean_t synced
= txg
<= spa_last_synced_txg(spa
);
2141 boolean_t frozen
= txg
> spa_freeze_txg(spa
);
2144 * If the txg of this itx has already been synced out, then
2145 * we don't need to commit this itx to an lwb. This is
2146 * because the data of this itx will have already been
2147 * written to the main pool. This is inherently racy, and
2148 * it's still ok to commit an itx whose txg has already
2149 * been synced; this will result in a write that's
2150 * unnecessary, but will do no harm.
2152 * With that said, we always want to commit TX_COMMIT itxs
2153 * to an lwb, regardless of whether or not that itx's txg
2154 * has been synced out. We do this to ensure any OPENED lwb
2155 * will always have at least one zil_commit_waiter_t linked
2158 * As a counter-example, if we skipped TX_COMMIT itx's
2159 * whose txg had already been synced, the following
2160 * situation could occur if we happened to be racing with
2163 * 1. we commit a non-TX_COMMIT itx to an lwb, where the
2164 * itx's txg is 10 and the last synced txg is 9.
2165 * 2. spa_sync finishes syncing out txg 10.
2166 * 3. we move to the next itx in the list, it's a TX_COMMIT
2167 * whose txg is 10, so we skip it rather than committing
2168 * it to the lwb used in (1).
2170 * If the itx that is skipped in (3) is the last TX_COMMIT
2171 * itx in the commit list, than it's possible for the lwb
2172 * used in (1) to remain in the OPENED state indefinitely.
2174 * To prevent the above scenario from occuring, ensuring
2175 * that once an lwb is OPENED it will transition to ISSUED
2176 * and eventually DONE, we always commit TX_COMMIT itx's to
2177 * an lwb here, even if that itx's txg has already been
2180 * Finally, if the pool is frozen, we _always_ commit the
2181 * itx. The point of freezing the pool is to prevent data
2182 * from being written to the main pool via spa_sync, and
2183 * instead rely solely on the ZIL to persistently store the
2184 * data; i.e. when the pool is frozen, the last synced txg
2185 * value can't be trusted.
2187 if (frozen
|| !synced
|| lrc
->lrc_txtype
== TX_COMMIT
) {
2189 lwb
= zil_lwb_commit(zilog
, itx
, lwb
);
2190 } else if (lrc
->lrc_txtype
== TX_COMMIT
) {
2191 ASSERT3P(lwb
, ==, NULL
);
2192 zil_commit_waiter_link_nolwb(
2193 itx
->itx_private
, &nolwb_waiters
);
2197 list_remove(&zilog
->zl_itx_commit_list
, itx
);
2198 zil_itx_destroy(itx
);
2203 * This indicates zio_alloc_zil() failed to allocate the
2204 * "next" lwb on-disk. When this happens, we must stall
2205 * the ZIL write pipeline; see the comment within
2206 * zil_commit_writer_stall() for more details.
2208 zil_commit_writer_stall(zilog
);
2211 * Additionally, we have to signal and mark the "nolwb"
2212 * waiters as "done" here, since without an lwb, we
2213 * can't do this via zil_lwb_flush_vdevs_done() like
2216 zil_commit_waiter_t
*zcw
;
2217 while (zcw
= list_head(&nolwb_waiters
)) {
2218 zil_commit_waiter_skip(zcw
);
2219 list_remove(&nolwb_waiters
, zcw
);
2222 ASSERT(list_is_empty(&nolwb_waiters
));
2223 ASSERT3P(lwb
, !=, NULL
);
2224 ASSERT3S(lwb
->lwb_state
, !=, LWB_STATE_ISSUED
);
2225 ASSERT3S(lwb
->lwb_state
, !=, LWB_STATE_WRITE_DONE
);
2226 ASSERT3S(lwb
->lwb_state
, !=, LWB_STATE_FLUSH_DONE
);
2229 * At this point, the ZIL block pointed at by the "lwb"
2230 * variable is in one of the following states: "closed"
2233 * If its "closed", then no itxs have been committed to
2234 * it, so there's no point in issuing its zio (i.e.
2237 * If its "open" state, then it contains one or more
2238 * itxs that eventually need to be committed to stable
2239 * storage. In this case we intentionally do not issue
2240 * the lwb's zio to disk yet, and instead rely on one of
2241 * the following two mechanisms for issuing the zio:
2243 * 1. Ideally, there will be more ZIL activity occuring
2244 * on the system, such that this function will be
2245 * immediately called again (not necessarily by the same
2246 * thread) and this lwb's zio will be issued via
2247 * zil_lwb_commit(). This way, the lwb is guaranteed to
2248 * be "full" when it is issued to disk, and we'll make
2249 * use of the lwb's size the best we can.
2251 * 2. If there isn't sufficient ZIL activity occuring on
2252 * the system, such that this lwb's zio isn't issued via
2253 * zil_lwb_commit(), zil_commit_waiter() will issue the
2254 * lwb's zio. If this occurs, the lwb is not guaranteed
2255 * to be "full" by the time its zio is issued, and means
2256 * the size of the lwb was "too large" given the amount
2257 * of ZIL activity occuring on the system at that time.
2259 * We do this for a couple of reasons:
2261 * 1. To try and reduce the number of IOPs needed to
2262 * write the same number of itxs. If an lwb has space
2263 * available in it's buffer for more itxs, and more itxs
2264 * will be committed relatively soon (relative to the
2265 * latency of performing a write), then it's beneficial
2266 * to wait for these "next" itxs. This way, more itxs
2267 * can be committed to stable storage with fewer writes.
2269 * 2. To try and use the largest lwb block size that the
2270 * incoming rate of itxs can support. Again, this is to
2271 * try and pack as many itxs into as few lwbs as
2272 * possible, without significantly impacting the latency
2273 * of each individual itx.
2279 * This function is responsible for ensuring the passed in commit waiter
2280 * (and associated commit itx) is committed to an lwb. If the waiter is
2281 * not already committed to an lwb, all itxs in the zilog's queue of
2282 * itxs will be processed. The assumption is the passed in waiter's
2283 * commit itx will found in the queue just like the other non-commit
2284 * itxs, such that when the entire queue is processed, the waiter will
2285 * have been commited to an lwb.
2287 * The lwb associated with the passed in waiter is not guaranteed to
2288 * have been issued by the time this function completes. If the lwb is
2289 * not issued, we rely on future calls to zil_commit_writer() to issue
2290 * the lwb, or the timeout mechanism found in zil_commit_waiter().
2293 zil_commit_writer(zilog_t
*zilog
, zil_commit_waiter_t
*zcw
)
2295 ASSERT(!MUTEX_HELD(&zilog
->zl_lock
));
2296 ASSERT(spa_writeable(zilog
->zl_spa
));
2298 mutex_enter(&zilog
->zl_issuer_lock
);
2300 if (zcw
->zcw_lwb
!= NULL
|| zcw
->zcw_done
) {
2302 * It's possible that, while we were waiting to acquire
2303 * the "zl_issuer_lock", another thread committed this
2304 * waiter to an lwb. If that occurs, we bail out early,
2305 * without processing any of the zilog's queue of itxs.
2307 * On certain workloads and system configurations, the
2308 * "zl_issuer_lock" can become highly contended. In an
2309 * attempt to reduce this contention, we immediately drop
2310 * the lock if the waiter has already been processed.
2312 * We've measured this optimization to reduce CPU spent
2313 * contending on this lock by up to 5%, using a system
2314 * with 32 CPUs, low latency storage (~50 usec writes),
2315 * and 1024 threads performing sync writes.
2320 zil_get_commit_list(zilog
);
2321 zil_prune_commit_list(zilog
);
2322 zil_process_commit_list(zilog
);
2325 mutex_exit(&zilog
->zl_issuer_lock
);
2329 zil_commit_waiter_timeout(zilog_t
*zilog
, zil_commit_waiter_t
*zcw
)
2331 ASSERT(!MUTEX_HELD(&zilog
->zl_issuer_lock
));
2332 ASSERT(MUTEX_HELD(&zcw
->zcw_lock
));
2333 ASSERT3B(zcw
->zcw_done
, ==, B_FALSE
);
2335 lwb_t
*lwb
= zcw
->zcw_lwb
;
2336 ASSERT3P(lwb
, !=, NULL
);
2337 ASSERT3S(lwb
->lwb_state
, !=, LWB_STATE_CLOSED
);
2340 * If the lwb has already been issued by another thread, we can
2341 * immediately return since there's no work to be done (the
2342 * point of this function is to issue the lwb). Additionally, we
2343 * do this prior to acquiring the zl_issuer_lock, to avoid
2344 * acquiring it when it's not necessary to do so.
2346 if (lwb
->lwb_state
== LWB_STATE_ISSUED
||
2347 lwb
->lwb_state
== LWB_STATE_WRITE_DONE
||
2348 lwb
->lwb_state
== LWB_STATE_FLUSH_DONE
)
2352 * In order to call zil_lwb_write_issue() we must hold the
2353 * zilog's "zl_issuer_lock". We can't simply acquire that lock,
2354 * since we're already holding the commit waiter's "zcw_lock",
2355 * and those two locks are aquired in the opposite order
2358 mutex_exit(&zcw
->zcw_lock
);
2359 mutex_enter(&zilog
->zl_issuer_lock
);
2360 mutex_enter(&zcw
->zcw_lock
);
2363 * Since we just dropped and re-acquired the commit waiter's
2364 * lock, we have to re-check to see if the waiter was marked
2365 * "done" during that process. If the waiter was marked "done",
2366 * the "lwb" pointer is no longer valid (it can be free'd after
2367 * the waiter is marked "done"), so without this check we could
2368 * wind up with a use-after-free error below.
2373 ASSERT3P(lwb
, ==, zcw
->zcw_lwb
);
2376 * We've already checked this above, but since we hadn't acquired
2377 * the zilog's zl_issuer_lock, we have to perform this check a
2378 * second time while holding the lock.
2380 * We don't need to hold the zl_lock since the lwb cannot transition
2381 * from OPENED to ISSUED while we hold the zl_issuer_lock. The lwb
2382 * _can_ transition from ISSUED to DONE, but it's OK to race with
2383 * that transition since we treat the lwb the same, whether it's in
2384 * the ISSUED or DONE states.
2386 * The important thing, is we treat the lwb differently depending on
2387 * if it's ISSUED or OPENED, and block any other threads that might
2388 * attempt to issue this lwb. For that reason we hold the
2389 * zl_issuer_lock when checking the lwb_state; we must not call
2390 * zil_lwb_write_issue() if the lwb had already been issued.
2392 * See the comment above the lwb_state_t structure definition for
2393 * more details on the lwb states, and locking requirements.
2395 if (lwb
->lwb_state
== LWB_STATE_ISSUED
||
2396 lwb
->lwb_state
== LWB_STATE_WRITE_DONE
||
2397 lwb
->lwb_state
== LWB_STATE_FLUSH_DONE
)
2400 ASSERT3S(lwb
->lwb_state
, ==, LWB_STATE_OPENED
);
2403 * As described in the comments above zil_commit_waiter() and
2404 * zil_process_commit_list(), we need to issue this lwb's zio
2405 * since we've reached the commit waiter's timeout and it still
2406 * hasn't been issued.
2408 lwb_t
*nlwb
= zil_lwb_write_issue(zilog
, lwb
);
2410 IMPLY(nlwb
!= NULL
, lwb
->lwb_state
!= LWB_STATE_OPENED
);
2413 * Since the lwb's zio hadn't been issued by the time this thread
2414 * reached its timeout, we reset the zilog's "zl_cur_used" field
2415 * to influence the zil block size selection algorithm.
2417 * By having to issue the lwb's zio here, it means the size of the
2418 * lwb was too large, given the incoming throughput of itxs. By
2419 * setting "zl_cur_used" to zero, we communicate this fact to the
2420 * block size selection algorithm, so it can take this informaiton
2421 * into account, and potentially select a smaller size for the
2422 * next lwb block that is allocated.
2424 zilog
->zl_cur_used
= 0;
2428 * When zil_lwb_write_issue() returns NULL, this
2429 * indicates zio_alloc_zil() failed to allocate the
2430 * "next" lwb on-disk. When this occurs, the ZIL write
2431 * pipeline must be stalled; see the comment within the
2432 * zil_commit_writer_stall() function for more details.
2434 * We must drop the commit waiter's lock prior to
2435 * calling zil_commit_writer_stall() or else we can wind
2436 * up with the following deadlock:
2438 * - This thread is waiting for the txg to sync while
2439 * holding the waiter's lock; txg_wait_synced() is
2440 * used within txg_commit_writer_stall().
2442 * - The txg can't sync because it is waiting for this
2443 * lwb's zio callback to call dmu_tx_commit().
2445 * - The lwb's zio callback can't call dmu_tx_commit()
2446 * because it's blocked trying to acquire the waiter's
2447 * lock, which occurs prior to calling dmu_tx_commit()
2449 mutex_exit(&zcw
->zcw_lock
);
2450 zil_commit_writer_stall(zilog
);
2451 mutex_enter(&zcw
->zcw_lock
);
2455 mutex_exit(&zilog
->zl_issuer_lock
);
2456 ASSERT(MUTEX_HELD(&zcw
->zcw_lock
));
2460 * This function is responsible for performing the following two tasks:
2462 * 1. its primary responsibility is to block until the given "commit
2463 * waiter" is considered "done".
2465 * 2. its secondary responsibility is to issue the zio for the lwb that
2466 * the given "commit waiter" is waiting on, if this function has
2467 * waited "long enough" and the lwb is still in the "open" state.
2469 * Given a sufficient amount of itxs being generated and written using
2470 * the ZIL, the lwb's zio will be issued via the zil_lwb_commit()
2471 * function. If this does not occur, this secondary responsibility will
2472 * ensure the lwb is issued even if there is not other synchronous
2473 * activity on the system.
2475 * For more details, see zil_process_commit_list(); more specifically,
2476 * the comment at the bottom of that function.
2479 zil_commit_waiter(zilog_t
*zilog
, zil_commit_waiter_t
*zcw
)
2481 ASSERT(!MUTEX_HELD(&zilog
->zl_lock
));
2482 ASSERT(!MUTEX_HELD(&zilog
->zl_issuer_lock
));
2483 ASSERT(spa_writeable(zilog
->zl_spa
));
2485 mutex_enter(&zcw
->zcw_lock
);
2488 * The timeout is scaled based on the lwb latency to avoid
2489 * significantly impacting the latency of each individual itx.
2490 * For more details, see the comment at the bottom of the
2491 * zil_process_commit_list() function.
2493 int pct
= MAX(zfs_commit_timeout_pct
, 1);
2494 hrtime_t sleep
= (zilog
->zl_last_lwb_latency
* pct
) / 100;
2495 hrtime_t wakeup
= gethrtime() + sleep
;
2496 boolean_t timedout
= B_FALSE
;
2498 while (!zcw
->zcw_done
) {
2499 ASSERT(MUTEX_HELD(&zcw
->zcw_lock
));
2501 lwb_t
*lwb
= zcw
->zcw_lwb
;
2504 * Usually, the waiter will have a non-NULL lwb field here,
2505 * but it's possible for it to be NULL as a result of
2506 * zil_commit() racing with spa_sync().
2508 * When zil_clean() is called, it's possible for the itxg
2509 * list (which may be cleaned via a taskq) to contain
2510 * commit itxs. When this occurs, the commit waiters linked
2511 * off of these commit itxs will not be committed to an
2512 * lwb. Additionally, these commit waiters will not be
2513 * marked done until zil_commit_waiter_skip() is called via
2516 * Thus, it's possible for this commit waiter (i.e. the
2517 * "zcw" variable) to be found in this "in between" state;
2518 * where it's "zcw_lwb" field is NULL, and it hasn't yet
2519 * been skipped, so it's "zcw_done" field is still B_FALSE.
2521 IMPLY(lwb
!= NULL
, lwb
->lwb_state
!= LWB_STATE_CLOSED
);
2523 if (lwb
!= NULL
&& lwb
->lwb_state
== LWB_STATE_OPENED
) {
2524 ASSERT3B(timedout
, ==, B_FALSE
);
2527 * If the lwb hasn't been issued yet, then we
2528 * need to wait with a timeout, in case this
2529 * function needs to issue the lwb after the
2530 * timeout is reached; responsibility (2) from
2531 * the comment above this function.
2533 clock_t timeleft
= cv_timedwait_hires(&zcw
->zcw_cv
,
2534 &zcw
->zcw_lock
, wakeup
, USEC2NSEC(1),
2535 CALLOUT_FLAG_ABSOLUTE
);
2537 if (timeleft
>= 0 || zcw
->zcw_done
)
2541 zil_commit_waiter_timeout(zilog
, zcw
);
2543 if (!zcw
->zcw_done
) {
2545 * If the commit waiter has already been
2546 * marked "done", it's possible for the
2547 * waiter's lwb structure to have already
2548 * been freed. Thus, we can only reliably
2549 * make these assertions if the waiter
2552 ASSERT3P(lwb
, ==, zcw
->zcw_lwb
);
2553 ASSERT3S(lwb
->lwb_state
, !=, LWB_STATE_OPENED
);
2557 * If the lwb isn't open, then it must have already
2558 * been issued. In that case, there's no need to
2559 * use a timeout when waiting for the lwb to
2562 * Additionally, if the lwb is NULL, the waiter
2563 * will soon be signalled and marked done via
2564 * zil_clean() and zil_itxg_clean(), so no timeout
2569 lwb
->lwb_state
== LWB_STATE_ISSUED
||
2570 lwb
->lwb_state
== LWB_STATE_WRITE_DONE
||
2571 lwb
->lwb_state
== LWB_STATE_FLUSH_DONE
);
2572 cv_wait(&zcw
->zcw_cv
, &zcw
->zcw_lock
);
2576 mutex_exit(&zcw
->zcw_lock
);
2579 static zil_commit_waiter_t
*
2580 zil_alloc_commit_waiter()
2582 zil_commit_waiter_t
*zcw
= kmem_cache_alloc(zil_zcw_cache
, KM_SLEEP
);
2584 cv_init(&zcw
->zcw_cv
, NULL
, CV_DEFAULT
, NULL
);
2585 mutex_init(&zcw
->zcw_lock
, NULL
, MUTEX_DEFAULT
, NULL
);
2586 list_link_init(&zcw
->zcw_node
);
2587 zcw
->zcw_lwb
= NULL
;
2588 zcw
->zcw_done
= B_FALSE
;
2589 zcw
->zcw_zio_error
= 0;
2595 zil_free_commit_waiter(zil_commit_waiter_t
*zcw
)
2597 ASSERT(!list_link_active(&zcw
->zcw_node
));
2598 ASSERT3P(zcw
->zcw_lwb
, ==, NULL
);
2599 ASSERT3B(zcw
->zcw_done
, ==, B_TRUE
);
2600 mutex_destroy(&zcw
->zcw_lock
);
2601 cv_destroy(&zcw
->zcw_cv
);
2602 kmem_cache_free(zil_zcw_cache
, zcw
);
2606 * This function is used to create a TX_COMMIT itx and assign it. This
2607 * way, it will be linked into the ZIL's list of synchronous itxs, and
2608 * then later committed to an lwb (or skipped) when
2609 * zil_process_commit_list() is called.
2612 zil_commit_itx_assign(zilog_t
*zilog
, zil_commit_waiter_t
*zcw
)
2614 dmu_tx_t
*tx
= dmu_tx_create(zilog
->zl_os
);
2615 VERIFY0(dmu_tx_assign(tx
, TXG_WAIT
));
2617 itx_t
*itx
= zil_itx_create(TX_COMMIT
, sizeof (lr_t
));
2618 itx
->itx_sync
= B_TRUE
;
2619 itx
->itx_private
= zcw
;
2621 zil_itx_assign(zilog
, itx
, tx
);
2627 * Commit ZFS Intent Log transactions (itxs) to stable storage.
2629 * When writing ZIL transactions to the on-disk representation of the
2630 * ZIL, the itxs are committed to a Log Write Block (lwb). Multiple
2631 * itxs can be committed to a single lwb. Once a lwb is written and
2632 * committed to stable storage (i.e. the lwb is written, and vdevs have
2633 * been flushed), each itx that was committed to that lwb is also
2634 * considered to be committed to stable storage.
2636 * When an itx is committed to an lwb, the log record (lr_t) contained
2637 * by the itx is copied into the lwb's zio buffer, and once this buffer
2638 * is written to disk, it becomes an on-disk ZIL block.
2640 * As itxs are generated, they're inserted into the ZIL's queue of
2641 * uncommitted itxs. The semantics of zil_commit() are such that it will
2642 * block until all itxs that were in the queue when it was called, are
2643 * committed to stable storage.
2645 * If "foid" is zero, this means all "synchronous" and "asynchronous"
2646 * itxs, for all objects in the dataset, will be committed to stable
2647 * storage prior to zil_commit() returning. If "foid" is non-zero, all
2648 * "synchronous" itxs for all objects, but only "asynchronous" itxs
2649 * that correspond to the foid passed in, will be committed to stable
2650 * storage prior to zil_commit() returning.
2652 * Generally speaking, when zil_commit() is called, the consumer doesn't
2653 * actually care about _all_ of the uncommitted itxs. Instead, they're
2654 * simply trying to waiting for a specific itx to be committed to disk,
2655 * but the interface(s) for interacting with the ZIL don't allow such
2656 * fine-grained communication. A better interface would allow a consumer
2657 * to create and assign an itx, and then pass a reference to this itx to
2658 * zil_commit(); such that zil_commit() would return as soon as that
2659 * specific itx was committed to disk (instead of waiting for _all_
2660 * itxs to be committed).
2662 * When a thread calls zil_commit() a special "commit itx" will be
2663 * generated, along with a corresponding "waiter" for this commit itx.
2664 * zil_commit() will wait on this waiter's CV, such that when the waiter
2665 * is marked done, and signalled, zil_commit() will return.
2667 * This commit itx is inserted into the queue of uncommitted itxs. This
2668 * provides an easy mechanism for determining which itxs were in the
2669 * queue prior to zil_commit() having been called, and which itxs were
2670 * added after zil_commit() was called.
2672 * The commit it is special; it doesn't have any on-disk representation.
2673 * When a commit itx is "committed" to an lwb, the waiter associated
2674 * with it is linked onto the lwb's list of waiters. Then, when that lwb
2675 * completes, each waiter on the lwb's list is marked done and signalled
2676 * -- allowing the thread waiting on the waiter to return from zil_commit().
2678 * It's important to point out a few critical factors that allow us
2679 * to make use of the commit itxs, commit waiters, per-lwb lists of
2680 * commit waiters, and zio completion callbacks like we're doing:
2682 * 1. The list of waiters for each lwb is traversed, and each commit
2683 * waiter is marked "done" and signalled, in the zio completion
2684 * callback of the lwb's zio[*].
2686 * * Actually, the waiters are signalled in the zio completion
2687 * callback of the root zio for the DKIOCFLUSHWRITECACHE commands
2688 * that are sent to the vdevs upon completion of the lwb zio.
2690 * 2. When the itxs are inserted into the ZIL's queue of uncommitted
2691 * itxs, the order in which they are inserted is preserved[*]; as
2692 * itxs are added to the queue, they are added to the tail of
2693 * in-memory linked lists.
2695 * When committing the itxs to lwbs (to be written to disk), they
2696 * are committed in the same order in which the itxs were added to
2697 * the uncommitted queue's linked list(s); i.e. the linked list of
2698 * itxs to commit is traversed from head to tail, and each itx is
2699 * committed to an lwb in that order.
2703 * - the order of "sync" itxs is preserved w.r.t. other
2704 * "sync" itxs, regardless of the corresponding objects.
2705 * - the order of "async" itxs is preserved w.r.t. other
2706 * "async" itxs corresponding to the same object.
2707 * - the order of "async" itxs is *not* preserved w.r.t. other
2708 * "async" itxs corresponding to different objects.
2709 * - the order of "sync" itxs w.r.t. "async" itxs (or vice
2710 * versa) is *not* preserved, even for itxs that correspond
2711 * to the same object.
2713 * For more details, see: zil_itx_assign(), zil_async_to_sync(),
2714 * zil_get_commit_list(), and zil_process_commit_list().
2716 * 3. The lwbs represent a linked list of blocks on disk. Thus, any
2717 * lwb cannot be considered committed to stable storage, until its
2718 * "previous" lwb is also committed to stable storage. This fact,
2719 * coupled with the fact described above, means that itxs are
2720 * committed in (roughly) the order in which they were generated.
2721 * This is essential because itxs are dependent on prior itxs.
2722 * Thus, we *must not* deem an itx as being committed to stable
2723 * storage, until *all* prior itxs have also been committed to
2726 * To enforce this ordering of lwb zio's, while still leveraging as
2727 * much of the underlying storage performance as possible, we rely
2728 * on two fundamental concepts:
2730 * 1. The creation and issuance of lwb zio's is protected by
2731 * the zilog's "zl_issuer_lock", which ensures only a single
2732 * thread is creating and/or issuing lwb's at a time
2733 * 2. The "previous" lwb is a child of the "current" lwb
2734 * (leveraging the zio parent-child depenency graph)
2736 * By relying on this parent-child zio relationship, we can have
2737 * many lwb zio's concurrently issued to the underlying storage,
2738 * but the order in which they complete will be the same order in
2739 * which they were created.
2742 zil_commit(zilog_t
*zilog
, uint64_t foid
)
2745 * We should never attempt to call zil_commit on a snapshot for
2746 * a couple of reasons:
2748 * 1. A snapshot may never be modified, thus it cannot have any
2749 * in-flight itxs that would have modified the dataset.
2751 * 2. By design, when zil_commit() is called, a commit itx will
2752 * be assigned to this zilog; as a result, the zilog will be
2753 * dirtied. We must not dirty the zilog of a snapshot; there's
2754 * checks in the code that enforce this invariant, and will
2755 * cause a panic if it's not upheld.
2757 ASSERT3B(dmu_objset_is_snapshot(zilog
->zl_os
), ==, B_FALSE
);
2759 if (zilog
->zl_sync
== ZFS_SYNC_DISABLED
)
2762 if (!spa_writeable(zilog
->zl_spa
)) {
2764 * If the SPA is not writable, there should never be any
2765 * pending itxs waiting to be committed to disk. If that
2766 * weren't true, we'd skip writing those itxs out, and
2767 * would break the sematics of zil_commit(); thus, we're
2768 * verifying that truth before we return to the caller.
2770 ASSERT(list_is_empty(&zilog
->zl_lwb_list
));
2771 ASSERT3P(zilog
->zl_last_lwb_opened
, ==, NULL
);
2772 for (int i
= 0; i
< TXG_SIZE
; i
++)
2773 ASSERT3P(zilog
->zl_itxg
[i
].itxg_itxs
, ==, NULL
);
2778 * If the ZIL is suspended, we don't want to dirty it by calling
2779 * zil_commit_itx_assign() below, nor can we write out
2780 * lwbs like would be done in zil_commit_write(). Thus, we
2781 * simply rely on txg_wait_synced() to maintain the necessary
2782 * semantics, and avoid calling those functions altogether.
2784 if (zilog
->zl_suspend
> 0) {
2785 txg_wait_synced(zilog
->zl_dmu_pool
, 0);
2789 zil_commit_impl(zilog
, foid
);
2793 zil_commit_impl(zilog_t
*zilog
, uint64_t foid
)
2796 * Move the "async" itxs for the specified foid to the "sync"
2797 * queues, such that they will be later committed (or skipped)
2798 * to an lwb when zil_process_commit_list() is called.
2800 * Since these "async" itxs must be committed prior to this
2801 * call to zil_commit returning, we must perform this operation
2802 * before we call zil_commit_itx_assign().
2804 zil_async_to_sync(zilog
, foid
);
2807 * We allocate a new "waiter" structure which will initially be
2808 * linked to the commit itx using the itx's "itx_private" field.
2809 * Since the commit itx doesn't represent any on-disk state,
2810 * when it's committed to an lwb, rather than copying the its
2811 * lr_t into the lwb's buffer, the commit itx's "waiter" will be
2812 * added to the lwb's list of waiters. Then, when the lwb is
2813 * committed to stable storage, each waiter in the lwb's list of
2814 * waiters will be marked "done", and signalled.
2816 * We must create the waiter and assign the commit itx prior to
2817 * calling zil_commit_writer(), or else our specific commit itx
2818 * is not guaranteed to be committed to an lwb prior to calling
2819 * zil_commit_waiter().
2821 zil_commit_waiter_t
*zcw
= zil_alloc_commit_waiter();
2822 zil_commit_itx_assign(zilog
, zcw
);
2824 zil_commit_writer(zilog
, zcw
);
2825 zil_commit_waiter(zilog
, zcw
);
2827 if (zcw
->zcw_zio_error
!= 0) {
2829 * If there was an error writing out the ZIL blocks that
2830 * this thread is waiting on, then we fallback to
2831 * relying on spa_sync() to write out the data this
2832 * thread is waiting on. Obviously this has performance
2833 * implications, but the expectation is for this to be
2834 * an exceptional case, and shouldn't occur often.
2836 DTRACE_PROBE2(zil__commit__io__error
,
2837 zilog_t
*, zilog
, zil_commit_waiter_t
*, zcw
);
2838 txg_wait_synced(zilog
->zl_dmu_pool
, 0);
2841 zil_free_commit_waiter(zcw
);
2845 * Called in syncing context to free committed log blocks and update log header.
2848 zil_sync(zilog_t
*zilog
, dmu_tx_t
*tx
)
2850 zil_header_t
*zh
= zil_header_in_syncing_context(zilog
);
2851 uint64_t txg
= dmu_tx_get_txg(tx
);
2852 spa_t
*spa
= zilog
->zl_spa
;
2853 uint64_t *replayed_seq
= &zilog
->zl_replayed_seq
[txg
& TXG_MASK
];
2857 * We don't zero out zl_destroy_txg, so make sure we don't try
2858 * to destroy it twice.
2860 if (spa_sync_pass(spa
) != 1)
2863 mutex_enter(&zilog
->zl_lock
);
2865 ASSERT(zilog
->zl_stop_sync
== 0);
2867 if (*replayed_seq
!= 0) {
2868 ASSERT(zh
->zh_replay_seq
< *replayed_seq
);
2869 zh
->zh_replay_seq
= *replayed_seq
;
2873 if (zilog
->zl_destroy_txg
== txg
) {
2874 blkptr_t blk
= zh
->zh_log
;
2876 ASSERT(list_head(&zilog
->zl_lwb_list
) == NULL
);
2878 bzero(zh
, sizeof (zil_header_t
));
2879 bzero(zilog
->zl_replayed_seq
, sizeof (zilog
->zl_replayed_seq
));
2881 if (zilog
->zl_keep_first
) {
2883 * If this block was part of log chain that couldn't
2884 * be claimed because a device was missing during
2885 * zil_claim(), but that device later returns,
2886 * then this block could erroneously appear valid.
2887 * To guard against this, assign a new GUID to the new
2888 * log chain so it doesn't matter what blk points to.
2890 zil_init_log_chain(zilog
, &blk
);
2895 while ((lwb
= list_head(&zilog
->zl_lwb_list
)) != NULL
) {
2896 zh
->zh_log
= lwb
->lwb_blk
;
2897 if (lwb
->lwb_buf
!= NULL
|| lwb
->lwb_max_txg
> txg
)
2899 list_remove(&zilog
->zl_lwb_list
, lwb
);
2900 zio_free(spa
, txg
, &lwb
->lwb_blk
);
2901 zil_free_lwb(zilog
, lwb
);
2904 * If we don't have anything left in the lwb list then
2905 * we've had an allocation failure and we need to zero
2906 * out the zil_header blkptr so that we don't end
2907 * up freeing the same block twice.
2909 if (list_head(&zilog
->zl_lwb_list
) == NULL
)
2910 BP_ZERO(&zh
->zh_log
);
2912 mutex_exit(&zilog
->zl_lock
);
2917 zil_lwb_cons(void *vbuf
, void *unused
, int kmflag
)
2920 list_create(&lwb
->lwb_waiters
, sizeof (zil_commit_waiter_t
),
2921 offsetof(zil_commit_waiter_t
, zcw_node
));
2922 avl_create(&lwb
->lwb_vdev_tree
, zil_lwb_vdev_compare
,
2923 sizeof (zil_vdev_node_t
), offsetof(zil_vdev_node_t
, zv_node
));
2924 mutex_init(&lwb
->lwb_vdev_lock
, NULL
, MUTEX_DEFAULT
, NULL
);
2930 zil_lwb_dest(void *vbuf
, void *unused
)
2933 mutex_destroy(&lwb
->lwb_vdev_lock
);
2934 avl_destroy(&lwb
->lwb_vdev_tree
);
2935 list_destroy(&lwb
->lwb_waiters
);
2941 zil_lwb_cache
= kmem_cache_create("zil_lwb_cache",
2942 sizeof (lwb_t
), 0, zil_lwb_cons
, zil_lwb_dest
, NULL
, NULL
, NULL
, 0);
2944 zil_zcw_cache
= kmem_cache_create("zil_zcw_cache",
2945 sizeof (zil_commit_waiter_t
), 0, NULL
, NULL
, NULL
, NULL
, NULL
, 0);
2951 kmem_cache_destroy(zil_zcw_cache
);
2952 kmem_cache_destroy(zil_lwb_cache
);
2956 zil_set_sync(zilog_t
*zilog
, uint64_t sync
)
2958 zilog
->zl_sync
= sync
;
2962 zil_set_logbias(zilog_t
*zilog
, uint64_t logbias
)
2964 zilog
->zl_logbias
= logbias
;
2968 zil_alloc(objset_t
*os
, zil_header_t
*zh_phys
)
2972 zilog
= kmem_zalloc(sizeof (zilog_t
), KM_SLEEP
);
2974 zilog
->zl_header
= zh_phys
;
2976 zilog
->zl_spa
= dmu_objset_spa(os
);
2977 zilog
->zl_dmu_pool
= dmu_objset_pool(os
);
2978 zilog
->zl_destroy_txg
= TXG_INITIAL
- 1;
2979 zilog
->zl_logbias
= dmu_objset_logbias(os
);
2980 zilog
->zl_sync
= dmu_objset_syncprop(os
);
2981 zilog
->zl_dirty_max_txg
= 0;
2982 zilog
->zl_last_lwb_opened
= NULL
;
2983 zilog
->zl_last_lwb_latency
= 0;
2985 mutex_init(&zilog
->zl_lock
, NULL
, MUTEX_DEFAULT
, NULL
);
2986 mutex_init(&zilog
->zl_issuer_lock
, NULL
, MUTEX_DEFAULT
, NULL
);
2988 for (int i
= 0; i
< TXG_SIZE
; i
++) {
2989 mutex_init(&zilog
->zl_itxg
[i
].itxg_lock
, NULL
,
2990 MUTEX_DEFAULT
, NULL
);
2993 list_create(&zilog
->zl_lwb_list
, sizeof (lwb_t
),
2994 offsetof(lwb_t
, lwb_node
));
2996 list_create(&zilog
->zl_itx_commit_list
, sizeof (itx_t
),
2997 offsetof(itx_t
, itx_node
));
2999 cv_init(&zilog
->zl_cv_suspend
, NULL
, CV_DEFAULT
, NULL
);
3005 zil_free(zilog_t
*zilog
)
3007 zilog
->zl_stop_sync
= 1;
3009 ASSERT0(zilog
->zl_suspend
);
3010 ASSERT0(zilog
->zl_suspending
);
3012 ASSERT(list_is_empty(&zilog
->zl_lwb_list
));
3013 list_destroy(&zilog
->zl_lwb_list
);
3015 ASSERT(list_is_empty(&zilog
->zl_itx_commit_list
));
3016 list_destroy(&zilog
->zl_itx_commit_list
);
3018 for (int i
= 0; i
< TXG_SIZE
; i
++) {
3020 * It's possible for an itx to be generated that doesn't dirty
3021 * a txg (e.g. ztest TX_TRUNCATE). So there's no zil_clean()
3022 * callback to remove the entry. We remove those here.
3024 * Also free up the ziltest itxs.
3026 if (zilog
->zl_itxg
[i
].itxg_itxs
)
3027 zil_itxg_clean(zilog
->zl_itxg
[i
].itxg_itxs
);
3028 mutex_destroy(&zilog
->zl_itxg
[i
].itxg_lock
);
3031 mutex_destroy(&zilog
->zl_issuer_lock
);
3032 mutex_destroy(&zilog
->zl_lock
);
3034 cv_destroy(&zilog
->zl_cv_suspend
);
3036 kmem_free(zilog
, sizeof (zilog_t
));
3040 * Open an intent log.
3043 zil_open(objset_t
*os
, zil_get_data_t
*get_data
)
3045 zilog_t
*zilog
= dmu_objset_zil(os
);
3047 ASSERT3P(zilog
->zl_get_data
, ==, NULL
);
3048 ASSERT3P(zilog
->zl_last_lwb_opened
, ==, NULL
);
3049 ASSERT(list_is_empty(&zilog
->zl_lwb_list
));
3051 zilog
->zl_get_data
= get_data
;
3057 * Close an intent log.
3060 zil_close(zilog_t
*zilog
)
3065 if (!dmu_objset_is_snapshot(zilog
->zl_os
)) {
3066 zil_commit(zilog
, 0);
3068 ASSERT3P(list_tail(&zilog
->zl_lwb_list
), ==, NULL
);
3069 ASSERT0(zilog
->zl_dirty_max_txg
);
3070 ASSERT3B(zilog_is_dirty(zilog
), ==, B_FALSE
);
3073 mutex_enter(&zilog
->zl_lock
);
3074 lwb
= list_tail(&zilog
->zl_lwb_list
);
3076 txg
= zilog
->zl_dirty_max_txg
;
3078 txg
= MAX(zilog
->zl_dirty_max_txg
, lwb
->lwb_max_txg
);
3079 mutex_exit(&zilog
->zl_lock
);
3082 * We need to use txg_wait_synced() to wait long enough for the
3083 * ZIL to be clean, and to wait for all pending lwbs to be
3087 txg_wait_synced(zilog
->zl_dmu_pool
, txg
);
3089 if (zilog_is_dirty(zilog
))
3090 zfs_dbgmsg("zil (%p) is dirty, txg %llu", zilog
, txg
);
3091 VERIFY(!zilog_is_dirty(zilog
));
3093 zilog
->zl_get_data
= NULL
;
3096 * We should have only one lwb left on the list; remove it now.
3098 mutex_enter(&zilog
->zl_lock
);
3099 lwb
= list_head(&zilog
->zl_lwb_list
);
3101 ASSERT3P(lwb
, ==, list_tail(&zilog
->zl_lwb_list
));
3102 ASSERT3S(lwb
->lwb_state
, !=, LWB_STATE_ISSUED
);
3103 list_remove(&zilog
->zl_lwb_list
, lwb
);
3104 zio_buf_free(lwb
->lwb_buf
, lwb
->lwb_sz
);
3105 zil_free_lwb(zilog
, lwb
);
3107 mutex_exit(&zilog
->zl_lock
);
3110 static char *suspend_tag
= "zil suspending";
3113 * Suspend an intent log. While in suspended mode, we still honor
3114 * synchronous semantics, but we rely on txg_wait_synced() to do it.
3115 * On old version pools, we suspend the log briefly when taking a
3116 * snapshot so that it will have an empty intent log.
3118 * Long holds are not really intended to be used the way we do here --
3119 * held for such a short time. A concurrent caller of dsl_dataset_long_held()
3120 * could fail. Therefore we take pains to only put a long hold if it is
3121 * actually necessary. Fortunately, it will only be necessary if the
3122 * objset is currently mounted (or the ZVOL equivalent). In that case it
3123 * will already have a long hold, so we are not really making things any worse.
3125 * Ideally, we would locate the existing long-holder (i.e. the zfsvfs_t or
3126 * zvol_state_t), and use their mechanism to prevent their hold from being
3127 * dropped (e.g. VFS_HOLD()). However, that would be even more pain for
3130 * if cookiep == NULL, this does both the suspend & resume.
3131 * Otherwise, it returns with the dataset "long held", and the cookie
3132 * should be passed into zil_resume().
3135 zil_suspend(const char *osname
, void **cookiep
)
3139 const zil_header_t
*zh
;
3142 error
= dmu_objset_hold(osname
, suspend_tag
, &os
);
3145 zilog
= dmu_objset_zil(os
);
3147 mutex_enter(&zilog
->zl_lock
);
3148 zh
= zilog
->zl_header
;
3150 if (zh
->zh_flags
& ZIL_REPLAY_NEEDED
) { /* unplayed log */
3151 mutex_exit(&zilog
->zl_lock
);
3152 dmu_objset_rele(os
, suspend_tag
);
3153 return (SET_ERROR(EBUSY
));
3157 * Don't put a long hold in the cases where we can avoid it. This
3158 * is when there is no cookie so we are doing a suspend & resume
3159 * (i.e. called from zil_vdev_offline()), and there's nothing to do
3160 * for the suspend because it's already suspended, or there's no ZIL.
3162 if (cookiep
== NULL
&& !zilog
->zl_suspending
&&
3163 (zilog
->zl_suspend
> 0 || BP_IS_HOLE(&zh
->zh_log
))) {
3164 mutex_exit(&zilog
->zl_lock
);
3165 dmu_objset_rele(os
, suspend_tag
);
3169 dsl_dataset_long_hold(dmu_objset_ds(os
), suspend_tag
);
3170 dsl_pool_rele(dmu_objset_pool(os
), suspend_tag
);
3172 zilog
->zl_suspend
++;
3174 if (zilog
->zl_suspend
> 1) {
3176 * Someone else is already suspending it.
3177 * Just wait for them to finish.
3180 while (zilog
->zl_suspending
)
3181 cv_wait(&zilog
->zl_cv_suspend
, &zilog
->zl_lock
);
3182 mutex_exit(&zilog
->zl_lock
);
3184 if (cookiep
== NULL
)
3192 * If there is no pointer to an on-disk block, this ZIL must not
3193 * be active (e.g. filesystem not mounted), so there's nothing
3196 if (BP_IS_HOLE(&zh
->zh_log
)) {
3197 ASSERT(cookiep
!= NULL
); /* fast path already handled */
3200 mutex_exit(&zilog
->zl_lock
);
3204 zilog
->zl_suspending
= B_TRUE
;
3205 mutex_exit(&zilog
->zl_lock
);
3208 * We need to use zil_commit_impl to ensure we wait for all
3209 * LWB_STATE_OPENED and LWB_STATE_ISSUED lwb's to be committed
3210 * to disk before proceeding. If we used zil_commit instead, it
3211 * would just call txg_wait_synced(), because zl_suspend is set.
3212 * txg_wait_synced() doesn't wait for these lwb's to be
3213 * LWB_STATE_FLUSH_DONE before returning.
3215 zil_commit_impl(zilog
, 0);
3218 * Now that we've ensured all lwb's are LWB_STATE_FLUSH_DONE, we
3219 * use txg_wait_synced() to ensure the data from the zilog has
3220 * migrated to the main pool before calling zil_destroy().
3222 txg_wait_synced(zilog
->zl_dmu_pool
, 0);
3224 zil_destroy(zilog
, B_FALSE
);
3226 mutex_enter(&zilog
->zl_lock
);
3227 zilog
->zl_suspending
= B_FALSE
;
3228 cv_broadcast(&zilog
->zl_cv_suspend
);
3229 mutex_exit(&zilog
->zl_lock
);
3231 if (cookiep
== NULL
)
3239 zil_resume(void *cookie
)
3241 objset_t
*os
= cookie
;
3242 zilog_t
*zilog
= dmu_objset_zil(os
);
3244 mutex_enter(&zilog
->zl_lock
);
3245 ASSERT(zilog
->zl_suspend
!= 0);
3246 zilog
->zl_suspend
--;
3247 mutex_exit(&zilog
->zl_lock
);
3248 dsl_dataset_long_rele(dmu_objset_ds(os
), suspend_tag
);
3249 dsl_dataset_rele(dmu_objset_ds(os
), suspend_tag
);
3252 typedef struct zil_replay_arg
{
3253 zil_replay_func_t
**zr_replay
;
3255 boolean_t zr_byteswap
;
3260 zil_replay_error(zilog_t
*zilog
, lr_t
*lr
, int error
)
3262 char name
[ZFS_MAX_DATASET_NAME_LEN
];
3264 zilog
->zl_replaying_seq
--; /* didn't actually replay this one */
3266 dmu_objset_name(zilog
->zl_os
, name
);
3268 cmn_err(CE_WARN
, "ZFS replay transaction error %d, "
3269 "dataset %s, seq 0x%llx, txtype %llu %s\n", error
, name
,
3270 (u_longlong_t
)lr
->lrc_seq
,
3271 (u_longlong_t
)(lr
->lrc_txtype
& ~TX_CI
),
3272 (lr
->lrc_txtype
& TX_CI
) ? "CI" : "");
3278 zil_replay_log_record(zilog_t
*zilog
, lr_t
*lr
, void *zra
, uint64_t claim_txg
)
3280 zil_replay_arg_t
*zr
= zra
;
3281 const zil_header_t
*zh
= zilog
->zl_header
;
3282 uint64_t reclen
= lr
->lrc_reclen
;
3283 uint64_t txtype
= lr
->lrc_txtype
;
3286 zilog
->zl_replaying_seq
= lr
->lrc_seq
;
3288 if (lr
->lrc_seq
<= zh
->zh_replay_seq
) /* already replayed */
3291 if (lr
->lrc_txg
< claim_txg
) /* already committed */
3294 /* Strip case-insensitive bit, still present in log record */
3297 if (txtype
== 0 || txtype
>= TX_MAX_TYPE
)
3298 return (zil_replay_error(zilog
, lr
, EINVAL
));
3301 * If this record type can be logged out of order, the object
3302 * (lr_foid) may no longer exist. That's legitimate, not an error.
3304 if (TX_OOO(txtype
)) {
3305 error
= dmu_object_info(zilog
->zl_os
,
3306 ((lr_ooo_t
*)lr
)->lr_foid
, NULL
);
3307 if (error
== ENOENT
|| error
== EEXIST
)
3312 * Make a copy of the data so we can revise and extend it.
3314 bcopy(lr
, zr
->zr_lr
, reclen
);
3317 * If this is a TX_WRITE with a blkptr, suck in the data.
3319 if (txtype
== TX_WRITE
&& reclen
== sizeof (lr_write_t
)) {
3320 error
= zil_read_log_data(zilog
, (lr_write_t
*)lr
,
3321 zr
->zr_lr
+ reclen
);
3323 return (zil_replay_error(zilog
, lr
, error
));
3327 * The log block containing this lr may have been byteswapped
3328 * so that we can easily examine common fields like lrc_txtype.
3329 * However, the log is a mix of different record types, and only the
3330 * replay vectors know how to byteswap their records. Therefore, if
3331 * the lr was byteswapped, undo it before invoking the replay vector.
3333 if (zr
->zr_byteswap
)
3334 byteswap_uint64_array(zr
->zr_lr
, reclen
);
3337 * We must now do two things atomically: replay this log record,
3338 * and update the log header sequence number to reflect the fact that
3339 * we did so. At the end of each replay function the sequence number
3340 * is updated if we are in replay mode.
3342 error
= zr
->zr_replay
[txtype
](zr
->zr_arg
, zr
->zr_lr
, zr
->zr_byteswap
);
3345 * The DMU's dnode layer doesn't see removes until the txg
3346 * commits, so a subsequent claim can spuriously fail with
3347 * EEXIST. So if we receive any error we try syncing out
3348 * any removes then retry the transaction. Note that we
3349 * specify B_FALSE for byteswap now, so we don't do it twice.
3351 txg_wait_synced(spa_get_dsl(zilog
->zl_spa
), 0);
3352 error
= zr
->zr_replay
[txtype
](zr
->zr_arg
, zr
->zr_lr
, B_FALSE
);
3354 return (zil_replay_error(zilog
, lr
, error
));
3361 zil_incr_blks(zilog_t
*zilog
, blkptr_t
*bp
, void *arg
, uint64_t claim_txg
)
3363 zilog
->zl_replay_blks
++;
3369 * If this dataset has a non-empty intent log, replay it and destroy it.
3372 zil_replay(objset_t
*os
, void *arg
, zil_replay_func_t
*replay_func
[TX_MAX_TYPE
])
3374 zilog_t
*zilog
= dmu_objset_zil(os
);
3375 const zil_header_t
*zh
= zilog
->zl_header
;
3376 zil_replay_arg_t zr
;
3378 if ((zh
->zh_flags
& ZIL_REPLAY_NEEDED
) == 0) {
3379 zil_destroy(zilog
, B_TRUE
);
3383 zr
.zr_replay
= replay_func
;
3385 zr
.zr_byteswap
= BP_SHOULD_BYTESWAP(&zh
->zh_log
);
3386 zr
.zr_lr
= kmem_alloc(2 * SPA_MAXBLOCKSIZE
, KM_SLEEP
);
3389 * Wait for in-progress removes to sync before starting replay.
3391 txg_wait_synced(zilog
->zl_dmu_pool
, 0);
3393 zilog
->zl_replay
= B_TRUE
;
3394 zilog
->zl_replay_time
= ddi_get_lbolt();
3395 ASSERT(zilog
->zl_replay_blks
== 0);
3396 (void) zil_parse(zilog
, zil_incr_blks
, zil_replay_log_record
, &zr
,
3398 kmem_free(zr
.zr_lr
, 2 * SPA_MAXBLOCKSIZE
);
3400 zil_destroy(zilog
, B_FALSE
);
3401 txg_wait_synced(zilog
->zl_dmu_pool
, zilog
->zl_destroy_txg
);
3402 zilog
->zl_replay
= B_FALSE
;
3406 zil_replaying(zilog_t
*zilog
, dmu_tx_t
*tx
)
3408 if (zilog
->zl_sync
== ZFS_SYNC_DISABLED
)
3411 if (zilog
->zl_replay
) {
3412 dsl_dataset_dirty(dmu_objset_ds(zilog
->zl_os
), tx
);
3413 zilog
->zl_replayed_seq
[dmu_tx_get_txg(tx
) & TXG_MASK
] =
3414 zilog
->zl_replaying_seq
;
3423 zil_reset(const char *osname
, void *arg
)
3427 error
= zil_suspend(osname
, NULL
);
3429 return (SET_ERROR(EEXIST
));