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]
25 * Copyright (c) 2018 Datto Inc.
28 /* Portions Copyright 2010 Robert Milkowski */
30 #include <sys/zfs_context.h>
32 #include <sys/spa_impl.h>
38 #include <sys/zil_impl.h>
39 #include <sys/dsl_dataset.h>
40 #include <sys/vdev_impl.h>
41 #include <sys/dmu_tx.h>
42 #include <sys/dsl_pool.h>
43 #include <sys/metaslab.h>
44 #include <sys/trace_zfs.h>
48 * The ZFS Intent Log (ZIL) saves "transaction records" (itxs) of system
49 * calls that change the file system. Each itx has enough information to
50 * be able to replay them after a system crash, power loss, or
51 * equivalent failure mode. These are stored in memory until either:
53 * 1. they are committed to the pool by the DMU transaction group
54 * (txg), at which point they can be discarded; or
55 * 2. they are committed to the on-disk ZIL for the dataset being
56 * modified (e.g. due to an fsync, O_DSYNC, or other synchronous
59 * In the event of a crash or power loss, the itxs contained by each
60 * dataset's on-disk ZIL will be replayed when that dataset is first
61 * instantiated (e.g. if the dataset is a normal filesystem, when it is
64 * As hinted at above, there is one ZIL per dataset (both the in-memory
65 * representation, and the on-disk representation). The on-disk format
66 * consists of 3 parts:
68 * - a single, per-dataset, ZIL header; which points to a chain of
69 * - zero or more ZIL blocks; each of which contains
70 * - zero or more ZIL records
72 * A ZIL record holds the information necessary to replay a single
73 * system call transaction. A ZIL block can hold many ZIL records, and
74 * the blocks are chained together, similarly to a singly linked list.
76 * Each ZIL block contains a block pointer (blkptr_t) to the next ZIL
77 * block in the chain, and the ZIL header points to the first block in
80 * Note, there is not a fixed place in the pool to hold these ZIL
81 * blocks; they are dynamically allocated and freed as needed from the
82 * blocks available on the pool, though they can be preferentially
83 * allocated from a dedicated "log" vdev.
87 * This controls the amount of time that a ZIL block (lwb) will remain
88 * "open" when it isn't "full", and it has a thread waiting for it to be
89 * committed to stable storage. Please refer to the zil_commit_waiter()
90 * function (and the comments within it) for more details.
92 static int zfs_commit_timeout_pct
= 5;
95 * See zil.h for more information about these fields.
97 static zil_stats_t zil_stats
= {
98 { "zil_commit_count", KSTAT_DATA_UINT64
},
99 { "zil_commit_writer_count", KSTAT_DATA_UINT64
},
100 { "zil_itx_count", KSTAT_DATA_UINT64
},
101 { "zil_itx_indirect_count", KSTAT_DATA_UINT64
},
102 { "zil_itx_indirect_bytes", KSTAT_DATA_UINT64
},
103 { "zil_itx_copied_count", KSTAT_DATA_UINT64
},
104 { "zil_itx_copied_bytes", KSTAT_DATA_UINT64
},
105 { "zil_itx_needcopy_count", KSTAT_DATA_UINT64
},
106 { "zil_itx_needcopy_bytes", KSTAT_DATA_UINT64
},
107 { "zil_itx_metaslab_normal_count", KSTAT_DATA_UINT64
},
108 { "zil_itx_metaslab_normal_bytes", KSTAT_DATA_UINT64
},
109 { "zil_itx_metaslab_slog_count", KSTAT_DATA_UINT64
},
110 { "zil_itx_metaslab_slog_bytes", KSTAT_DATA_UINT64
},
113 static kstat_t
*zil_ksp
;
116 * Disable intent logging replay. This global ZIL switch affects all pools.
118 int zil_replay_disable
= 0;
121 * Disable the DKIOCFLUSHWRITECACHE commands that are normally sent to
122 * the disk(s) by the ZIL after an LWB write has completed. Setting this
123 * will cause ZIL corruption on power loss if a volatile out-of-order
124 * write cache is enabled.
126 static int zil_nocacheflush
= 0;
129 * Limit SLOG write size per commit executed with synchronous priority.
130 * Any writes above that will be executed with lower (asynchronous) priority
131 * to limit potential SLOG device abuse by single active ZIL writer.
133 static unsigned long zil_slog_bulk
= 768 * 1024;
135 static kmem_cache_t
*zil_lwb_cache
;
136 static kmem_cache_t
*zil_zcw_cache
;
138 #define LWB_EMPTY(lwb) ((BP_GET_LSIZE(&lwb->lwb_blk) - \
139 sizeof (zil_chain_t)) == (lwb->lwb_sz - lwb->lwb_nused))
142 zil_bp_compare(const void *x1
, const void *x2
)
144 const dva_t
*dva1
= &((zil_bp_node_t
*)x1
)->zn_dva
;
145 const dva_t
*dva2
= &((zil_bp_node_t
*)x2
)->zn_dva
;
147 int cmp
= TREE_CMP(DVA_GET_VDEV(dva1
), DVA_GET_VDEV(dva2
));
151 return (TREE_CMP(DVA_GET_OFFSET(dva1
), DVA_GET_OFFSET(dva2
)));
155 zil_bp_tree_init(zilog_t
*zilog
)
157 avl_create(&zilog
->zl_bp_tree
, zil_bp_compare
,
158 sizeof (zil_bp_node_t
), offsetof(zil_bp_node_t
, zn_node
));
162 zil_bp_tree_fini(zilog_t
*zilog
)
164 avl_tree_t
*t
= &zilog
->zl_bp_tree
;
168 while ((zn
= avl_destroy_nodes(t
, &cookie
)) != NULL
)
169 kmem_free(zn
, sizeof (zil_bp_node_t
));
175 zil_bp_tree_add(zilog_t
*zilog
, const blkptr_t
*bp
)
177 avl_tree_t
*t
= &zilog
->zl_bp_tree
;
182 if (BP_IS_EMBEDDED(bp
))
185 dva
= BP_IDENTITY(bp
);
187 if (avl_find(t
, dva
, &where
) != NULL
)
188 return (SET_ERROR(EEXIST
));
190 zn
= kmem_alloc(sizeof (zil_bp_node_t
), KM_SLEEP
);
192 avl_insert(t
, zn
, where
);
197 static zil_header_t
*
198 zil_header_in_syncing_context(zilog_t
*zilog
)
200 return ((zil_header_t
*)zilog
->zl_header
);
204 zil_init_log_chain(zilog_t
*zilog
, blkptr_t
*bp
)
206 zio_cksum_t
*zc
= &bp
->blk_cksum
;
208 (void) random_get_pseudo_bytes((void *)&zc
->zc_word
[ZIL_ZC_GUID_0
],
209 sizeof (zc
->zc_word
[ZIL_ZC_GUID_0
]));
210 (void) random_get_pseudo_bytes((void *)&zc
->zc_word
[ZIL_ZC_GUID_1
],
211 sizeof (zc
->zc_word
[ZIL_ZC_GUID_1
]));
212 zc
->zc_word
[ZIL_ZC_OBJSET
] = dmu_objset_id(zilog
->zl_os
);
213 zc
->zc_word
[ZIL_ZC_SEQ
] = 1ULL;
217 * Read a log block and make sure it's valid.
220 zil_read_log_block(zilog_t
*zilog
, boolean_t decrypt
, const blkptr_t
*bp
,
221 blkptr_t
*nbp
, void *dst
, char **end
)
223 enum zio_flag zio_flags
= ZIO_FLAG_CANFAIL
;
224 arc_flags_t aflags
= ARC_FLAG_WAIT
;
225 arc_buf_t
*abuf
= NULL
;
229 if (zilog
->zl_header
->zh_claim_txg
== 0)
230 zio_flags
|= ZIO_FLAG_SPECULATIVE
| ZIO_FLAG_SCRUB
;
232 if (!(zilog
->zl_header
->zh_flags
& ZIL_CLAIM_LR_SEQ_VALID
))
233 zio_flags
|= ZIO_FLAG_SPECULATIVE
;
236 zio_flags
|= ZIO_FLAG_RAW
;
238 SET_BOOKMARK(&zb
, bp
->blk_cksum
.zc_word
[ZIL_ZC_OBJSET
],
239 ZB_ZIL_OBJECT
, ZB_ZIL_LEVEL
, bp
->blk_cksum
.zc_word
[ZIL_ZC_SEQ
]);
241 error
= arc_read(NULL
, zilog
->zl_spa
, bp
, arc_getbuf_func
,
242 &abuf
, ZIO_PRIORITY_SYNC_READ
, zio_flags
, &aflags
, &zb
);
245 zio_cksum_t cksum
= bp
->blk_cksum
;
248 * Validate the checksummed log block.
250 * Sequence numbers should be... sequential. The checksum
251 * verifier for the next block should be bp's checksum plus 1.
253 * Also check the log chain linkage and size used.
255 cksum
.zc_word
[ZIL_ZC_SEQ
]++;
257 if (BP_GET_CHECKSUM(bp
) == ZIO_CHECKSUM_ZILOG2
) {
258 zil_chain_t
*zilc
= abuf
->b_data
;
259 char *lr
= (char *)(zilc
+ 1);
260 uint64_t len
= zilc
->zc_nused
- sizeof (zil_chain_t
);
262 if (bcmp(&cksum
, &zilc
->zc_next_blk
.blk_cksum
,
263 sizeof (cksum
)) || BP_IS_HOLE(&zilc
->zc_next_blk
)) {
264 error
= SET_ERROR(ECKSUM
);
266 ASSERT3U(len
, <=, SPA_OLD_MAXBLOCKSIZE
);
268 *end
= (char *)dst
+ len
;
269 *nbp
= zilc
->zc_next_blk
;
272 char *lr
= abuf
->b_data
;
273 uint64_t size
= BP_GET_LSIZE(bp
);
274 zil_chain_t
*zilc
= (zil_chain_t
*)(lr
+ size
) - 1;
276 if (bcmp(&cksum
, &zilc
->zc_next_blk
.blk_cksum
,
277 sizeof (cksum
)) || BP_IS_HOLE(&zilc
->zc_next_blk
) ||
278 (zilc
->zc_nused
> (size
- sizeof (*zilc
)))) {
279 error
= SET_ERROR(ECKSUM
);
281 ASSERT3U(zilc
->zc_nused
, <=,
282 SPA_OLD_MAXBLOCKSIZE
);
283 bcopy(lr
, dst
, zilc
->zc_nused
);
284 *end
= (char *)dst
+ zilc
->zc_nused
;
285 *nbp
= zilc
->zc_next_blk
;
289 arc_buf_destroy(abuf
, &abuf
);
296 * Read a TX_WRITE log data block.
299 zil_read_log_data(zilog_t
*zilog
, const lr_write_t
*lr
, void *wbuf
)
301 enum zio_flag zio_flags
= ZIO_FLAG_CANFAIL
;
302 const blkptr_t
*bp
= &lr
->lr_blkptr
;
303 arc_flags_t aflags
= ARC_FLAG_WAIT
;
304 arc_buf_t
*abuf
= NULL
;
308 if (BP_IS_HOLE(bp
)) {
310 bzero(wbuf
, MAX(BP_GET_LSIZE(bp
), lr
->lr_length
));
314 if (zilog
->zl_header
->zh_claim_txg
== 0)
315 zio_flags
|= ZIO_FLAG_SPECULATIVE
| ZIO_FLAG_SCRUB
;
318 * If we are not using the resulting data, we are just checking that
319 * it hasn't been corrupted so we don't need to waste CPU time
320 * decompressing and decrypting it.
323 zio_flags
|= ZIO_FLAG_RAW
;
325 SET_BOOKMARK(&zb
, dmu_objset_id(zilog
->zl_os
), lr
->lr_foid
,
326 ZB_ZIL_LEVEL
, lr
->lr_offset
/ BP_GET_LSIZE(bp
));
328 error
= arc_read(NULL
, zilog
->zl_spa
, bp
, arc_getbuf_func
, &abuf
,
329 ZIO_PRIORITY_SYNC_READ
, zio_flags
, &aflags
, &zb
);
333 bcopy(abuf
->b_data
, wbuf
, arc_buf_size(abuf
));
334 arc_buf_destroy(abuf
, &abuf
);
341 * Parse the intent log, and call parse_func for each valid record within.
344 zil_parse(zilog_t
*zilog
, zil_parse_blk_func_t
*parse_blk_func
,
345 zil_parse_lr_func_t
*parse_lr_func
, void *arg
, uint64_t txg
,
348 const zil_header_t
*zh
= zilog
->zl_header
;
349 boolean_t claimed
= !!zh
->zh_claim_txg
;
350 uint64_t claim_blk_seq
= claimed
? zh
->zh_claim_blk_seq
: UINT64_MAX
;
351 uint64_t claim_lr_seq
= claimed
? zh
->zh_claim_lr_seq
: UINT64_MAX
;
352 uint64_t max_blk_seq
= 0;
353 uint64_t max_lr_seq
= 0;
354 uint64_t blk_count
= 0;
355 uint64_t lr_count
= 0;
356 blkptr_t blk
, next_blk
;
360 bzero(&next_blk
, sizeof (blkptr_t
));
363 * Old logs didn't record the maximum zh_claim_lr_seq.
365 if (!(zh
->zh_flags
& ZIL_CLAIM_LR_SEQ_VALID
))
366 claim_lr_seq
= UINT64_MAX
;
369 * Starting at the block pointed to by zh_log we read the log chain.
370 * For each block in the chain we strongly check that block to
371 * ensure its validity. We stop when an invalid block is found.
372 * For each block pointer in the chain we call parse_blk_func().
373 * For each record in each valid block we call parse_lr_func().
374 * If the log has been claimed, stop if we encounter a sequence
375 * number greater than the highest claimed sequence number.
377 lrbuf
= zio_buf_alloc(SPA_OLD_MAXBLOCKSIZE
);
378 zil_bp_tree_init(zilog
);
380 for (blk
= zh
->zh_log
; !BP_IS_HOLE(&blk
); blk
= next_blk
) {
381 uint64_t blk_seq
= blk
.blk_cksum
.zc_word
[ZIL_ZC_SEQ
];
385 if (blk_seq
> claim_blk_seq
)
388 error
= parse_blk_func(zilog
, &blk
, arg
, txg
);
391 ASSERT3U(max_blk_seq
, <, blk_seq
);
392 max_blk_seq
= blk_seq
;
395 if (max_lr_seq
== claim_lr_seq
&& max_blk_seq
== claim_blk_seq
)
398 error
= zil_read_log_block(zilog
, decrypt
, &blk
, &next_blk
,
403 for (lrp
= lrbuf
; lrp
< end
; lrp
+= reclen
) {
404 lr_t
*lr
= (lr_t
*)lrp
;
405 reclen
= lr
->lrc_reclen
;
406 ASSERT3U(reclen
, >=, sizeof (lr_t
));
407 if (lr
->lrc_seq
> claim_lr_seq
)
410 error
= parse_lr_func(zilog
, lr
, arg
, txg
);
413 ASSERT3U(max_lr_seq
, <, lr
->lrc_seq
);
414 max_lr_seq
= lr
->lrc_seq
;
419 zilog
->zl_parse_error
= error
;
420 zilog
->zl_parse_blk_seq
= max_blk_seq
;
421 zilog
->zl_parse_lr_seq
= max_lr_seq
;
422 zilog
->zl_parse_blk_count
= blk_count
;
423 zilog
->zl_parse_lr_count
= lr_count
;
425 ASSERT(!claimed
|| !(zh
->zh_flags
& ZIL_CLAIM_LR_SEQ_VALID
) ||
426 (max_blk_seq
== claim_blk_seq
&& max_lr_seq
== claim_lr_seq
) ||
427 (decrypt
&& error
== EIO
));
429 zil_bp_tree_fini(zilog
);
430 zio_buf_free(lrbuf
, SPA_OLD_MAXBLOCKSIZE
);
436 zil_clear_log_block(zilog_t
*zilog
, const blkptr_t
*bp
, void *tx
,
440 ASSERT(!BP_IS_HOLE(bp
));
443 * As we call this function from the context of a rewind to a
444 * checkpoint, each ZIL block whose txg is later than the txg
445 * that we rewind to is invalid. Thus, we return -1 so
446 * zil_parse() doesn't attempt to read it.
448 if (bp
->blk_birth
>= first_txg
)
451 if (zil_bp_tree_add(zilog
, bp
) != 0)
454 zio_free(zilog
->zl_spa
, first_txg
, bp
);
459 zil_noop_log_record(zilog_t
*zilog
, const lr_t
*lrc
, void *tx
,
462 (void) zilog
, (void) lrc
, (void) tx
, (void) first_txg
;
467 zil_claim_log_block(zilog_t
*zilog
, const blkptr_t
*bp
, void *tx
,
471 * Claim log block if not already committed and not already claimed.
472 * If tx == NULL, just verify that the block is claimable.
474 if (BP_IS_HOLE(bp
) || bp
->blk_birth
< first_txg
||
475 zil_bp_tree_add(zilog
, bp
) != 0)
478 return (zio_wait(zio_claim(NULL
, zilog
->zl_spa
,
479 tx
== NULL
? 0 : first_txg
, bp
, spa_claim_notify
, NULL
,
480 ZIO_FLAG_CANFAIL
| ZIO_FLAG_SPECULATIVE
| ZIO_FLAG_SCRUB
)));
484 zil_claim_log_record(zilog_t
*zilog
, const lr_t
*lrc
, void *tx
,
487 lr_write_t
*lr
= (lr_write_t
*)lrc
;
490 if (lrc
->lrc_txtype
!= TX_WRITE
)
494 * If the block is not readable, don't claim it. This can happen
495 * in normal operation when a log block is written to disk before
496 * some of the dmu_sync() blocks it points to. In this case, the
497 * transaction cannot have been committed to anyone (we would have
498 * waited for all writes to be stable first), so it is semantically
499 * correct to declare this the end of the log.
501 if (lr
->lr_blkptr
.blk_birth
>= first_txg
) {
502 error
= zil_read_log_data(zilog
, lr
, NULL
);
507 return (zil_claim_log_block(zilog
, &lr
->lr_blkptr
, tx
, first_txg
));
511 zil_free_log_block(zilog_t
*zilog
, const blkptr_t
*bp
, void *tx
,
516 zio_free(zilog
->zl_spa
, dmu_tx_get_txg(tx
), bp
);
522 zil_free_log_record(zilog_t
*zilog
, const lr_t
*lrc
, void *tx
,
525 lr_write_t
*lr
= (lr_write_t
*)lrc
;
526 blkptr_t
*bp
= &lr
->lr_blkptr
;
529 * If we previously claimed it, we need to free it.
531 if (claim_txg
!= 0 && lrc
->lrc_txtype
== TX_WRITE
&&
532 bp
->blk_birth
>= claim_txg
&& zil_bp_tree_add(zilog
, bp
) == 0 &&
534 zio_free(zilog
->zl_spa
, dmu_tx_get_txg(tx
), bp
);
540 zil_lwb_vdev_compare(const void *x1
, const void *x2
)
542 const uint64_t v1
= ((zil_vdev_node_t
*)x1
)->zv_vdev
;
543 const uint64_t v2
= ((zil_vdev_node_t
*)x2
)->zv_vdev
;
545 return (TREE_CMP(v1
, v2
));
549 zil_alloc_lwb(zilog_t
*zilog
, blkptr_t
*bp
, boolean_t slog
, uint64_t txg
,
554 lwb
= kmem_cache_alloc(zil_lwb_cache
, KM_SLEEP
);
555 lwb
->lwb_zilog
= zilog
;
557 lwb
->lwb_fastwrite
= fastwrite
;
558 lwb
->lwb_slog
= slog
;
559 lwb
->lwb_state
= LWB_STATE_CLOSED
;
560 lwb
->lwb_buf
= zio_buf_alloc(BP_GET_LSIZE(bp
));
561 lwb
->lwb_max_txg
= txg
;
562 lwb
->lwb_write_zio
= NULL
;
563 lwb
->lwb_root_zio
= NULL
;
565 lwb
->lwb_issued_timestamp
= 0;
566 if (BP_GET_CHECKSUM(bp
) == ZIO_CHECKSUM_ZILOG2
) {
567 lwb
->lwb_nused
= sizeof (zil_chain_t
);
568 lwb
->lwb_sz
= BP_GET_LSIZE(bp
);
571 lwb
->lwb_sz
= BP_GET_LSIZE(bp
) - sizeof (zil_chain_t
);
574 mutex_enter(&zilog
->zl_lock
);
575 list_insert_tail(&zilog
->zl_lwb_list
, lwb
);
576 mutex_exit(&zilog
->zl_lock
);
578 ASSERT(!MUTEX_HELD(&lwb
->lwb_vdev_lock
));
579 ASSERT(avl_is_empty(&lwb
->lwb_vdev_tree
));
580 VERIFY(list_is_empty(&lwb
->lwb_waiters
));
581 VERIFY(list_is_empty(&lwb
->lwb_itxs
));
587 zil_free_lwb(zilog_t
*zilog
, lwb_t
*lwb
)
589 ASSERT(MUTEX_HELD(&zilog
->zl_lock
));
590 ASSERT(!MUTEX_HELD(&lwb
->lwb_vdev_lock
));
591 VERIFY(list_is_empty(&lwb
->lwb_waiters
));
592 VERIFY(list_is_empty(&lwb
->lwb_itxs
));
593 ASSERT(avl_is_empty(&lwb
->lwb_vdev_tree
));
594 ASSERT3P(lwb
->lwb_write_zio
, ==, NULL
);
595 ASSERT3P(lwb
->lwb_root_zio
, ==, NULL
);
596 ASSERT3U(lwb
->lwb_max_txg
, <=, spa_syncing_txg(zilog
->zl_spa
));
597 ASSERT(lwb
->lwb_state
== LWB_STATE_CLOSED
||
598 lwb
->lwb_state
== LWB_STATE_FLUSH_DONE
);
601 * Clear the zilog's field to indicate this lwb is no longer
602 * valid, and prevent use-after-free errors.
604 if (zilog
->zl_last_lwb_opened
== lwb
)
605 zilog
->zl_last_lwb_opened
= NULL
;
607 kmem_cache_free(zil_lwb_cache
, lwb
);
611 * Called when we create in-memory log transactions so that we know
612 * to cleanup the itxs at the end of spa_sync().
615 zilog_dirty(zilog_t
*zilog
, uint64_t txg
)
617 dsl_pool_t
*dp
= zilog
->zl_dmu_pool
;
618 dsl_dataset_t
*ds
= dmu_objset_ds(zilog
->zl_os
);
620 ASSERT(spa_writeable(zilog
->zl_spa
));
622 if (ds
->ds_is_snapshot
)
623 panic("dirtying snapshot!");
625 if (txg_list_add(&dp
->dp_dirty_zilogs
, zilog
, txg
)) {
626 /* up the hold count until we can be written out */
627 dmu_buf_add_ref(ds
->ds_dbuf
, zilog
);
629 zilog
->zl_dirty_max_txg
= MAX(txg
, zilog
->zl_dirty_max_txg
);
634 * Determine if the zil is dirty in the specified txg. Callers wanting to
635 * ensure that the dirty state does not change must hold the itxg_lock for
636 * the specified txg. Holding the lock will ensure that the zil cannot be
637 * dirtied (zil_itx_assign) or cleaned (zil_clean) while we check its current
640 static boolean_t __maybe_unused
641 zilog_is_dirty_in_txg(zilog_t
*zilog
, uint64_t txg
)
643 dsl_pool_t
*dp
= zilog
->zl_dmu_pool
;
645 if (txg_list_member(&dp
->dp_dirty_zilogs
, zilog
, txg
& TXG_MASK
))
651 * Determine if the zil is dirty. The zil is considered dirty if it has
652 * any pending itx records that have not been cleaned by zil_clean().
655 zilog_is_dirty(zilog_t
*zilog
)
657 dsl_pool_t
*dp
= zilog
->zl_dmu_pool
;
659 for (int t
= 0; t
< TXG_SIZE
; t
++) {
660 if (txg_list_member(&dp
->dp_dirty_zilogs
, zilog
, t
))
667 * Create an on-disk intent log.
670 zil_create(zilog_t
*zilog
)
672 const zil_header_t
*zh
= zilog
->zl_header
;
678 boolean_t fastwrite
= FALSE
;
679 boolean_t slog
= FALSE
;
682 * Wait for any previous destroy to complete.
684 txg_wait_synced(zilog
->zl_dmu_pool
, zilog
->zl_destroy_txg
);
686 ASSERT(zh
->zh_claim_txg
== 0);
687 ASSERT(zh
->zh_replay_seq
== 0);
692 * Allocate an initial log block if:
693 * - there isn't one already
694 * - the existing block is the wrong endianness
696 if (BP_IS_HOLE(&blk
) || BP_SHOULD_BYTESWAP(&blk
)) {
697 tx
= dmu_tx_create(zilog
->zl_os
);
698 VERIFY0(dmu_tx_assign(tx
, TXG_WAIT
));
699 dsl_dataset_dirty(dmu_objset_ds(zilog
->zl_os
), tx
);
700 txg
= dmu_tx_get_txg(tx
);
702 if (!BP_IS_HOLE(&blk
)) {
703 zio_free(zilog
->zl_spa
, txg
, &blk
);
707 error
= zio_alloc_zil(zilog
->zl_spa
, zilog
->zl_os
, txg
, &blk
,
708 ZIL_MIN_BLKSZ
, &slog
);
712 zil_init_log_chain(zilog
, &blk
);
716 * Allocate a log write block (lwb) for the first log block.
719 lwb
= zil_alloc_lwb(zilog
, &blk
, slog
, txg
, fastwrite
);
722 * If we just allocated the first log block, commit our transaction
723 * and wait for zil_sync() to stuff the block pointer into zh_log.
724 * (zh is part of the MOS, so we cannot modify it in open context.)
728 txg_wait_synced(zilog
->zl_dmu_pool
, txg
);
731 ASSERT(error
!= 0 || bcmp(&blk
, &zh
->zh_log
, sizeof (blk
)) == 0);
732 IMPLY(error
== 0, lwb
!= NULL
);
738 * In one tx, free all log blocks and clear the log header. If keep_first
739 * is set, then we're replaying a log with no content. We want to keep the
740 * first block, however, so that the first synchronous transaction doesn't
741 * require a txg_wait_synced() in zil_create(). We don't need to
742 * txg_wait_synced() here either when keep_first is set, because both
743 * zil_create() and zil_destroy() will wait for any in-progress destroys
747 zil_destroy(zilog_t
*zilog
, boolean_t keep_first
)
749 const zil_header_t
*zh
= zilog
->zl_header
;
755 * Wait for any previous destroy to complete.
757 txg_wait_synced(zilog
->zl_dmu_pool
, zilog
->zl_destroy_txg
);
759 zilog
->zl_old_header
= *zh
; /* debugging aid */
761 if (BP_IS_HOLE(&zh
->zh_log
))
764 tx
= dmu_tx_create(zilog
->zl_os
);
765 VERIFY0(dmu_tx_assign(tx
, TXG_WAIT
));
766 dsl_dataset_dirty(dmu_objset_ds(zilog
->zl_os
), tx
);
767 txg
= dmu_tx_get_txg(tx
);
769 mutex_enter(&zilog
->zl_lock
);
771 ASSERT3U(zilog
->zl_destroy_txg
, <, txg
);
772 zilog
->zl_destroy_txg
= txg
;
773 zilog
->zl_keep_first
= keep_first
;
775 if (!list_is_empty(&zilog
->zl_lwb_list
)) {
776 ASSERT(zh
->zh_claim_txg
== 0);
778 while ((lwb
= list_head(&zilog
->zl_lwb_list
)) != NULL
) {
779 if (lwb
->lwb_fastwrite
)
780 metaslab_fastwrite_unmark(zilog
->zl_spa
,
783 list_remove(&zilog
->zl_lwb_list
, lwb
);
784 if (lwb
->lwb_buf
!= NULL
)
785 zio_buf_free(lwb
->lwb_buf
, lwb
->lwb_sz
);
786 zio_free(zilog
->zl_spa
, txg
, &lwb
->lwb_blk
);
787 zil_free_lwb(zilog
, lwb
);
789 } else if (!keep_first
) {
790 zil_destroy_sync(zilog
, tx
);
792 mutex_exit(&zilog
->zl_lock
);
798 zil_destroy_sync(zilog_t
*zilog
, dmu_tx_t
*tx
)
800 ASSERT(list_is_empty(&zilog
->zl_lwb_list
));
801 (void) zil_parse(zilog
, zil_free_log_block
,
802 zil_free_log_record
, tx
, zilog
->zl_header
->zh_claim_txg
, B_FALSE
);
806 zil_claim(dsl_pool_t
*dp
, dsl_dataset_t
*ds
, void *txarg
)
808 dmu_tx_t
*tx
= txarg
;
815 error
= dmu_objset_own_obj(dp
, ds
->ds_object
,
816 DMU_OST_ANY
, B_FALSE
, B_FALSE
, FTAG
, &os
);
819 * EBUSY indicates that the objset is inconsistent, in which
820 * case it can not have a ZIL.
822 if (error
!= EBUSY
) {
823 cmn_err(CE_WARN
, "can't open objset for %llu, error %u",
824 (unsigned long long)ds
->ds_object
, error
);
830 zilog
= dmu_objset_zil(os
);
831 zh
= zil_header_in_syncing_context(zilog
);
832 ASSERT3U(tx
->tx_txg
, ==, spa_first_txg(zilog
->zl_spa
));
833 first_txg
= spa_min_claim_txg(zilog
->zl_spa
);
836 * If the spa_log_state is not set to be cleared, check whether
837 * the current uberblock is a checkpoint one and if the current
838 * header has been claimed before moving on.
840 * If the current uberblock is a checkpointed uberblock then
841 * one of the following scenarios took place:
843 * 1] We are currently rewinding to the checkpoint of the pool.
844 * 2] We crashed in the middle of a checkpoint rewind but we
845 * did manage to write the checkpointed uberblock to the
846 * vdev labels, so when we tried to import the pool again
847 * the checkpointed uberblock was selected from the import
850 * In both cases we want to zero out all the ZIL blocks, except
851 * the ones that have been claimed at the time of the checkpoint
852 * (their zh_claim_txg != 0). The reason is that these blocks
853 * may be corrupted since we may have reused their locations on
854 * disk after we took the checkpoint.
856 * We could try to set spa_log_state to SPA_LOG_CLEAR earlier
857 * when we first figure out whether the current uberblock is
858 * checkpointed or not. Unfortunately, that would discard all
859 * the logs, including the ones that are claimed, and we would
862 if (spa_get_log_state(zilog
->zl_spa
) == SPA_LOG_CLEAR
||
863 (zilog
->zl_spa
->spa_uberblock
.ub_checkpoint_txg
!= 0 &&
864 zh
->zh_claim_txg
== 0)) {
865 if (!BP_IS_HOLE(&zh
->zh_log
)) {
866 (void) zil_parse(zilog
, zil_clear_log_block
,
867 zil_noop_log_record
, tx
, first_txg
, B_FALSE
);
869 BP_ZERO(&zh
->zh_log
);
870 if (os
->os_encrypted
)
871 os
->os_next_write_raw
[tx
->tx_txg
& TXG_MASK
] = B_TRUE
;
872 dsl_dataset_dirty(dmu_objset_ds(os
), tx
);
873 dmu_objset_disown(os
, B_FALSE
, FTAG
);
878 * If we are not rewinding and opening the pool normally, then
879 * the min_claim_txg should be equal to the first txg of the pool.
881 ASSERT3U(first_txg
, ==, spa_first_txg(zilog
->zl_spa
));
884 * Claim all log blocks if we haven't already done so, and remember
885 * the highest claimed sequence number. This ensures that if we can
886 * read only part of the log now (e.g. due to a missing device),
887 * but we can read the entire log later, we will not try to replay
888 * or destroy beyond the last block we successfully claimed.
890 ASSERT3U(zh
->zh_claim_txg
, <=, first_txg
);
891 if (zh
->zh_claim_txg
== 0 && !BP_IS_HOLE(&zh
->zh_log
)) {
892 (void) zil_parse(zilog
, zil_claim_log_block
,
893 zil_claim_log_record
, tx
, first_txg
, B_FALSE
);
894 zh
->zh_claim_txg
= first_txg
;
895 zh
->zh_claim_blk_seq
= zilog
->zl_parse_blk_seq
;
896 zh
->zh_claim_lr_seq
= zilog
->zl_parse_lr_seq
;
897 if (zilog
->zl_parse_lr_count
|| zilog
->zl_parse_blk_count
> 1)
898 zh
->zh_flags
|= ZIL_REPLAY_NEEDED
;
899 zh
->zh_flags
|= ZIL_CLAIM_LR_SEQ_VALID
;
900 if (os
->os_encrypted
)
901 os
->os_next_write_raw
[tx
->tx_txg
& TXG_MASK
] = B_TRUE
;
902 dsl_dataset_dirty(dmu_objset_ds(os
), tx
);
905 ASSERT3U(first_txg
, ==, (spa_last_synced_txg(zilog
->zl_spa
) + 1));
906 dmu_objset_disown(os
, B_FALSE
, FTAG
);
911 * Check the log by walking the log chain.
912 * Checksum errors are ok as they indicate the end of the chain.
913 * Any other error (no device or read failure) returns an error.
916 zil_check_log_chain(dsl_pool_t
*dp
, dsl_dataset_t
*ds
, void *tx
)
926 error
= dmu_objset_from_ds(ds
, &os
);
928 cmn_err(CE_WARN
, "can't open objset %llu, error %d",
929 (unsigned long long)ds
->ds_object
, error
);
933 zilog
= dmu_objset_zil(os
);
934 bp
= (blkptr_t
*)&zilog
->zl_header
->zh_log
;
936 if (!BP_IS_HOLE(bp
)) {
938 boolean_t valid
= B_TRUE
;
941 * Check the first block and determine if it's on a log device
942 * which may have been removed or faulted prior to loading this
943 * pool. If so, there's no point in checking the rest of the
944 * log as its content should have already been synced to the
947 spa_config_enter(os
->os_spa
, SCL_STATE
, FTAG
, RW_READER
);
948 vd
= vdev_lookup_top(os
->os_spa
, DVA_GET_VDEV(&bp
->blk_dva
[0]));
949 if (vd
->vdev_islog
&& vdev_is_dead(vd
))
950 valid
= vdev_log_state_valid(vd
);
951 spa_config_exit(os
->os_spa
, SCL_STATE
, FTAG
);
957 * Check whether the current uberblock is checkpointed (e.g.
958 * we are rewinding) and whether the current header has been
959 * claimed or not. If it hasn't then skip verifying it. We
960 * do this because its ZIL blocks may be part of the pool's
961 * state before the rewind, which is no longer valid.
963 zil_header_t
*zh
= zil_header_in_syncing_context(zilog
);
964 if (zilog
->zl_spa
->spa_uberblock
.ub_checkpoint_txg
!= 0 &&
965 zh
->zh_claim_txg
== 0)
970 * Because tx == NULL, zil_claim_log_block() will not actually claim
971 * any blocks, but just determine whether it is possible to do so.
972 * In addition to checking the log chain, zil_claim_log_block()
973 * will invoke zio_claim() with a done func of spa_claim_notify(),
974 * which will update spa_max_claim_txg. See spa_load() for details.
976 error
= zil_parse(zilog
, zil_claim_log_block
, zil_claim_log_record
, tx
,
977 zilog
->zl_header
->zh_claim_txg
? -1ULL :
978 spa_min_claim_txg(os
->os_spa
), B_FALSE
);
980 return ((error
== ECKSUM
|| error
== ENOENT
) ? 0 : error
);
984 * When an itx is "skipped", this function is used to properly mark the
985 * waiter as "done, and signal any thread(s) waiting on it. An itx can
986 * be skipped (and not committed to an lwb) for a variety of reasons,
987 * one of them being that the itx was committed via spa_sync(), prior to
988 * it being committed to an lwb; this can happen if a thread calling
989 * zil_commit() is racing with spa_sync().
992 zil_commit_waiter_skip(zil_commit_waiter_t
*zcw
)
994 mutex_enter(&zcw
->zcw_lock
);
995 ASSERT3B(zcw
->zcw_done
, ==, B_FALSE
);
996 zcw
->zcw_done
= B_TRUE
;
997 cv_broadcast(&zcw
->zcw_cv
);
998 mutex_exit(&zcw
->zcw_lock
);
1002 * This function is used when the given waiter is to be linked into an
1003 * lwb's "lwb_waiter" list; i.e. when the itx is committed to the lwb.
1004 * At this point, the waiter will no longer be referenced by the itx,
1005 * and instead, will be referenced by the lwb.
1008 zil_commit_waiter_link_lwb(zil_commit_waiter_t
*zcw
, lwb_t
*lwb
)
1011 * The lwb_waiters field of the lwb is protected by the zilog's
1012 * zl_lock, thus it must be held when calling this function.
1014 ASSERT(MUTEX_HELD(&lwb
->lwb_zilog
->zl_lock
));
1016 mutex_enter(&zcw
->zcw_lock
);
1017 ASSERT(!list_link_active(&zcw
->zcw_node
));
1018 ASSERT3P(zcw
->zcw_lwb
, ==, NULL
);
1019 ASSERT3P(lwb
, !=, NULL
);
1020 ASSERT(lwb
->lwb_state
== LWB_STATE_OPENED
||
1021 lwb
->lwb_state
== LWB_STATE_ISSUED
||
1022 lwb
->lwb_state
== LWB_STATE_WRITE_DONE
);
1024 list_insert_tail(&lwb
->lwb_waiters
, zcw
);
1026 mutex_exit(&zcw
->zcw_lock
);
1030 * This function is used when zio_alloc_zil() fails to allocate a ZIL
1031 * block, and the given waiter must be linked to the "nolwb waiters"
1032 * list inside of zil_process_commit_list().
1035 zil_commit_waiter_link_nolwb(zil_commit_waiter_t
*zcw
, list_t
*nolwb
)
1037 mutex_enter(&zcw
->zcw_lock
);
1038 ASSERT(!list_link_active(&zcw
->zcw_node
));
1039 ASSERT3P(zcw
->zcw_lwb
, ==, NULL
);
1040 list_insert_tail(nolwb
, zcw
);
1041 mutex_exit(&zcw
->zcw_lock
);
1045 zil_lwb_add_block(lwb_t
*lwb
, const blkptr_t
*bp
)
1047 avl_tree_t
*t
= &lwb
->lwb_vdev_tree
;
1049 zil_vdev_node_t
*zv
, zvsearch
;
1050 int ndvas
= BP_GET_NDVAS(bp
);
1053 if (zil_nocacheflush
)
1056 mutex_enter(&lwb
->lwb_vdev_lock
);
1057 for (i
= 0; i
< ndvas
; i
++) {
1058 zvsearch
.zv_vdev
= DVA_GET_VDEV(&bp
->blk_dva
[i
]);
1059 if (avl_find(t
, &zvsearch
, &where
) == NULL
) {
1060 zv
= kmem_alloc(sizeof (*zv
), KM_SLEEP
);
1061 zv
->zv_vdev
= zvsearch
.zv_vdev
;
1062 avl_insert(t
, zv
, where
);
1065 mutex_exit(&lwb
->lwb_vdev_lock
);
1069 zil_lwb_flush_defer(lwb_t
*lwb
, lwb_t
*nlwb
)
1071 avl_tree_t
*src
= &lwb
->lwb_vdev_tree
;
1072 avl_tree_t
*dst
= &nlwb
->lwb_vdev_tree
;
1073 void *cookie
= NULL
;
1074 zil_vdev_node_t
*zv
;
1076 ASSERT3S(lwb
->lwb_state
, ==, LWB_STATE_WRITE_DONE
);
1077 ASSERT3S(nlwb
->lwb_state
, !=, LWB_STATE_WRITE_DONE
);
1078 ASSERT3S(nlwb
->lwb_state
, !=, LWB_STATE_FLUSH_DONE
);
1081 * While 'lwb' is at a point in its lifetime where lwb_vdev_tree does
1082 * not need the protection of lwb_vdev_lock (it will only be modified
1083 * while holding zilog->zl_lock) as its writes and those of its
1084 * children have all completed. The younger 'nlwb' may be waiting on
1085 * future writes to additional vdevs.
1087 mutex_enter(&nlwb
->lwb_vdev_lock
);
1089 * Tear down the 'lwb' vdev tree, ensuring that entries which do not
1090 * exist in 'nlwb' are moved to it, freeing any would-be duplicates.
1092 while ((zv
= avl_destroy_nodes(src
, &cookie
)) != NULL
) {
1095 if (avl_find(dst
, zv
, &where
) == NULL
) {
1096 avl_insert(dst
, zv
, where
);
1098 kmem_free(zv
, sizeof (*zv
));
1101 mutex_exit(&nlwb
->lwb_vdev_lock
);
1105 zil_lwb_add_txg(lwb_t
*lwb
, uint64_t txg
)
1107 lwb
->lwb_max_txg
= MAX(lwb
->lwb_max_txg
, txg
);
1111 * This function is a called after all vdevs associated with a given lwb
1112 * write have completed their DKIOCFLUSHWRITECACHE command; or as soon
1113 * as the lwb write completes, if "zil_nocacheflush" is set. Further,
1114 * all "previous" lwb's will have completed before this function is
1115 * called; i.e. this function is called for all previous lwbs before
1116 * it's called for "this" lwb (enforced via zio the dependencies
1117 * configured in zil_lwb_set_zio_dependency()).
1119 * The intention is for this function to be called as soon as the
1120 * contents of an lwb are considered "stable" on disk, and will survive
1121 * any sudden loss of power. At this point, any threads waiting for the
1122 * lwb to reach this state are signalled, and the "waiter" structures
1123 * are marked "done".
1126 zil_lwb_flush_vdevs_done(zio_t
*zio
)
1128 lwb_t
*lwb
= zio
->io_private
;
1129 zilog_t
*zilog
= lwb
->lwb_zilog
;
1130 dmu_tx_t
*tx
= lwb
->lwb_tx
;
1131 zil_commit_waiter_t
*zcw
;
1134 spa_config_exit(zilog
->zl_spa
, SCL_STATE
, lwb
);
1136 zio_buf_free(lwb
->lwb_buf
, lwb
->lwb_sz
);
1138 mutex_enter(&zilog
->zl_lock
);
1141 * Ensure the lwb buffer pointer is cleared before releasing the
1142 * txg. If we have had an allocation failure and the txg is
1143 * waiting to sync then we want zil_sync() to remove the lwb so
1144 * that it's not picked up as the next new one in
1145 * zil_process_commit_list(). zil_sync() will only remove the
1146 * lwb if lwb_buf is null.
1148 lwb
->lwb_buf
= NULL
;
1151 ASSERT3U(lwb
->lwb_issued_timestamp
, >, 0);
1152 zilog
->zl_last_lwb_latency
= gethrtime() - lwb
->lwb_issued_timestamp
;
1154 lwb
->lwb_root_zio
= NULL
;
1156 ASSERT3S(lwb
->lwb_state
, ==, LWB_STATE_WRITE_DONE
);
1157 lwb
->lwb_state
= LWB_STATE_FLUSH_DONE
;
1159 if (zilog
->zl_last_lwb_opened
== lwb
) {
1161 * Remember the highest committed log sequence number
1162 * for ztest. We only update this value when all the log
1163 * writes succeeded, because ztest wants to ASSERT that
1164 * it got the whole log chain.
1166 zilog
->zl_commit_lr_seq
= zilog
->zl_lr_seq
;
1169 while ((itx
= list_head(&lwb
->lwb_itxs
)) != NULL
) {
1170 list_remove(&lwb
->lwb_itxs
, itx
);
1171 zil_itx_destroy(itx
);
1174 while ((zcw
= list_head(&lwb
->lwb_waiters
)) != NULL
) {
1175 mutex_enter(&zcw
->zcw_lock
);
1177 ASSERT(list_link_active(&zcw
->zcw_node
));
1178 list_remove(&lwb
->lwb_waiters
, zcw
);
1180 ASSERT3P(zcw
->zcw_lwb
, ==, lwb
);
1181 zcw
->zcw_lwb
= NULL
;
1183 * We expect any ZIO errors from child ZIOs to have been
1184 * propagated "up" to this specific LWB's root ZIO, in
1185 * order for this error handling to work correctly. This
1186 * includes ZIO errors from either this LWB's write or
1187 * flush, as well as any errors from other dependent LWBs
1188 * (e.g. a root LWB ZIO that might be a child of this LWB).
1190 * With that said, it's important to note that LWB flush
1191 * errors are not propagated up to the LWB root ZIO.
1192 * This is incorrect behavior, and results in VDEV flush
1193 * errors not being handled correctly here. See the
1194 * comment above the call to "zio_flush" for details.
1197 zcw
->zcw_zio_error
= zio
->io_error
;
1199 ASSERT3B(zcw
->zcw_done
, ==, B_FALSE
);
1200 zcw
->zcw_done
= B_TRUE
;
1201 cv_broadcast(&zcw
->zcw_cv
);
1203 mutex_exit(&zcw
->zcw_lock
);
1206 mutex_exit(&zilog
->zl_lock
);
1209 * Now that we've written this log block, we have a stable pointer
1210 * to the next block in the chain, so it's OK to let the txg in
1211 * which we allocated the next block sync.
1217 * This is called when an lwb's write zio completes. The callback's
1218 * purpose is to issue the DKIOCFLUSHWRITECACHE commands for the vdevs
1219 * in the lwb's lwb_vdev_tree. The tree will contain the vdevs involved
1220 * in writing out this specific lwb's data, and in the case that cache
1221 * flushes have been deferred, vdevs involved in writing the data for
1222 * previous lwbs. The writes corresponding to all the vdevs in the
1223 * lwb_vdev_tree will have completed by the time this is called, due to
1224 * the zio dependencies configured in zil_lwb_set_zio_dependency(),
1225 * which takes deferred flushes into account. The lwb will be "done"
1226 * once zil_lwb_flush_vdevs_done() is called, which occurs in the zio
1227 * completion callback for the lwb's root zio.
1230 zil_lwb_write_done(zio_t
*zio
)
1232 lwb_t
*lwb
= zio
->io_private
;
1233 spa_t
*spa
= zio
->io_spa
;
1234 zilog_t
*zilog
= lwb
->lwb_zilog
;
1235 avl_tree_t
*t
= &lwb
->lwb_vdev_tree
;
1236 void *cookie
= NULL
;
1237 zil_vdev_node_t
*zv
;
1240 ASSERT3S(spa_config_held(spa
, SCL_STATE
, RW_READER
), !=, 0);
1242 ASSERT(BP_GET_COMPRESS(zio
->io_bp
) == ZIO_COMPRESS_OFF
);
1243 ASSERT(BP_GET_TYPE(zio
->io_bp
) == DMU_OT_INTENT_LOG
);
1244 ASSERT(BP_GET_LEVEL(zio
->io_bp
) == 0);
1245 ASSERT(BP_GET_BYTEORDER(zio
->io_bp
) == ZFS_HOST_BYTEORDER
);
1246 ASSERT(!BP_IS_GANG(zio
->io_bp
));
1247 ASSERT(!BP_IS_HOLE(zio
->io_bp
));
1248 ASSERT(BP_GET_FILL(zio
->io_bp
) == 0);
1250 abd_free(zio
->io_abd
);
1252 mutex_enter(&zilog
->zl_lock
);
1253 ASSERT3S(lwb
->lwb_state
, ==, LWB_STATE_ISSUED
);
1254 lwb
->lwb_state
= LWB_STATE_WRITE_DONE
;
1255 lwb
->lwb_write_zio
= NULL
;
1256 lwb
->lwb_fastwrite
= FALSE
;
1257 nlwb
= list_next(&zilog
->zl_lwb_list
, lwb
);
1258 mutex_exit(&zilog
->zl_lock
);
1260 if (avl_numnodes(t
) == 0)
1264 * If there was an IO error, we're not going to call zio_flush()
1265 * on these vdevs, so we simply empty the tree and free the
1266 * nodes. We avoid calling zio_flush() since there isn't any
1267 * good reason for doing so, after the lwb block failed to be
1270 * Additionally, we don't perform any further error handling at
1271 * this point (e.g. setting "zcw_zio_error" appropriately), as
1272 * we expect that to occur in "zil_lwb_flush_vdevs_done" (thus,
1273 * we expect any error seen here, to have been propagated to
1276 if (zio
->io_error
!= 0) {
1277 while ((zv
= avl_destroy_nodes(t
, &cookie
)) != NULL
)
1278 kmem_free(zv
, sizeof (*zv
));
1283 * If this lwb does not have any threads waiting for it to
1284 * complete, we want to defer issuing the DKIOCFLUSHWRITECACHE
1285 * command to the vdevs written to by "this" lwb, and instead
1286 * rely on the "next" lwb to handle the DKIOCFLUSHWRITECACHE
1287 * command for those vdevs. Thus, we merge the vdev tree of
1288 * "this" lwb with the vdev tree of the "next" lwb in the list,
1289 * and assume the "next" lwb will handle flushing the vdevs (or
1290 * deferring the flush(s) again).
1292 * This is a useful performance optimization, especially for
1293 * workloads with lots of async write activity and few sync
1294 * write and/or fsync activity, as it has the potential to
1295 * coalesce multiple flush commands to a vdev into one.
1297 if (list_head(&lwb
->lwb_waiters
) == NULL
&& nlwb
!= NULL
) {
1298 zil_lwb_flush_defer(lwb
, nlwb
);
1299 ASSERT(avl_is_empty(&lwb
->lwb_vdev_tree
));
1303 while ((zv
= avl_destroy_nodes(t
, &cookie
)) != NULL
) {
1304 vdev_t
*vd
= vdev_lookup_top(spa
, zv
->zv_vdev
);
1307 * The "ZIO_FLAG_DONT_PROPAGATE" is currently
1308 * always used within "zio_flush". This means,
1309 * any errors when flushing the vdev(s), will
1310 * (unfortunately) not be handled correctly,
1311 * since these "zio_flush" errors will not be
1312 * propagated up to "zil_lwb_flush_vdevs_done".
1314 zio_flush(lwb
->lwb_root_zio
, vd
);
1316 kmem_free(zv
, sizeof (*zv
));
1321 zil_lwb_set_zio_dependency(zilog_t
*zilog
, lwb_t
*lwb
)
1323 lwb_t
*last_lwb_opened
= zilog
->zl_last_lwb_opened
;
1325 ASSERT(MUTEX_HELD(&zilog
->zl_issuer_lock
));
1326 ASSERT(MUTEX_HELD(&zilog
->zl_lock
));
1329 * The zilog's "zl_last_lwb_opened" field is used to build the
1330 * lwb/zio dependency chain, which is used to preserve the
1331 * ordering of lwb completions that is required by the semantics
1332 * of the ZIL. Each new lwb zio becomes a parent of the
1333 * "previous" lwb zio, such that the new lwb's zio cannot
1334 * complete until the "previous" lwb's zio completes.
1336 * This is required by the semantics of zil_commit(); the commit
1337 * waiters attached to the lwbs will be woken in the lwb zio's
1338 * completion callback, so this zio dependency graph ensures the
1339 * waiters are woken in the correct order (the same order the
1340 * lwbs were created).
1342 if (last_lwb_opened
!= NULL
&&
1343 last_lwb_opened
->lwb_state
!= LWB_STATE_FLUSH_DONE
) {
1344 ASSERT(last_lwb_opened
->lwb_state
== LWB_STATE_OPENED
||
1345 last_lwb_opened
->lwb_state
== LWB_STATE_ISSUED
||
1346 last_lwb_opened
->lwb_state
== LWB_STATE_WRITE_DONE
);
1348 ASSERT3P(last_lwb_opened
->lwb_root_zio
, !=, NULL
);
1349 zio_add_child(lwb
->lwb_root_zio
,
1350 last_lwb_opened
->lwb_root_zio
);
1353 * If the previous lwb's write hasn't already completed,
1354 * we also want to order the completion of the lwb write
1355 * zios (above, we only order the completion of the lwb
1356 * root zios). This is required because of how we can
1357 * defer the DKIOCFLUSHWRITECACHE commands for each lwb.
1359 * When the DKIOCFLUSHWRITECACHE commands are deferred,
1360 * the previous lwb will rely on this lwb to flush the
1361 * vdevs written to by that previous lwb. Thus, we need
1362 * to ensure this lwb doesn't issue the flush until
1363 * after the previous lwb's write completes. We ensure
1364 * this ordering by setting the zio parent/child
1365 * relationship here.
1367 * Without this relationship on the lwb's write zio,
1368 * it's possible for this lwb's write to complete prior
1369 * to the previous lwb's write completing; and thus, the
1370 * vdevs for the previous lwb would be flushed prior to
1371 * that lwb's data being written to those vdevs (the
1372 * vdevs are flushed in the lwb write zio's completion
1373 * handler, zil_lwb_write_done()).
1375 if (last_lwb_opened
->lwb_state
!= LWB_STATE_WRITE_DONE
) {
1376 ASSERT(last_lwb_opened
->lwb_state
== LWB_STATE_OPENED
||
1377 last_lwb_opened
->lwb_state
== LWB_STATE_ISSUED
);
1379 ASSERT3P(last_lwb_opened
->lwb_write_zio
, !=, NULL
);
1380 zio_add_child(lwb
->lwb_write_zio
,
1381 last_lwb_opened
->lwb_write_zio
);
1388 * This function's purpose is to "open" an lwb such that it is ready to
1389 * accept new itxs being committed to it. To do this, the lwb's zio
1390 * structures are created, and linked to the lwb. This function is
1391 * idempotent; if the passed in lwb has already been opened, this
1392 * function is essentially a no-op.
1395 zil_lwb_write_open(zilog_t
*zilog
, lwb_t
*lwb
)
1397 zbookmark_phys_t zb
;
1398 zio_priority_t prio
;
1400 ASSERT(MUTEX_HELD(&zilog
->zl_issuer_lock
));
1401 ASSERT3P(lwb
, !=, NULL
);
1402 EQUIV(lwb
->lwb_root_zio
== NULL
, lwb
->lwb_state
== LWB_STATE_CLOSED
);
1403 EQUIV(lwb
->lwb_root_zio
!= NULL
, lwb
->lwb_state
== LWB_STATE_OPENED
);
1405 SET_BOOKMARK(&zb
, lwb
->lwb_blk
.blk_cksum
.zc_word
[ZIL_ZC_OBJSET
],
1406 ZB_ZIL_OBJECT
, ZB_ZIL_LEVEL
,
1407 lwb
->lwb_blk
.blk_cksum
.zc_word
[ZIL_ZC_SEQ
]);
1409 /* Lock so zil_sync() doesn't fastwrite_unmark after zio is created */
1410 mutex_enter(&zilog
->zl_lock
);
1411 if (lwb
->lwb_root_zio
== NULL
) {
1412 abd_t
*lwb_abd
= abd_get_from_buf(lwb
->lwb_buf
,
1413 BP_GET_LSIZE(&lwb
->lwb_blk
));
1415 if (!lwb
->lwb_fastwrite
) {
1416 metaslab_fastwrite_mark(zilog
->zl_spa
, &lwb
->lwb_blk
);
1417 lwb
->lwb_fastwrite
= 1;
1420 if (!lwb
->lwb_slog
|| zilog
->zl_cur_used
<= zil_slog_bulk
)
1421 prio
= ZIO_PRIORITY_SYNC_WRITE
;
1423 prio
= ZIO_PRIORITY_ASYNC_WRITE
;
1425 lwb
->lwb_root_zio
= zio_root(zilog
->zl_spa
,
1426 zil_lwb_flush_vdevs_done
, lwb
, ZIO_FLAG_CANFAIL
);
1427 ASSERT3P(lwb
->lwb_root_zio
, !=, NULL
);
1429 lwb
->lwb_write_zio
= zio_rewrite(lwb
->lwb_root_zio
,
1430 zilog
->zl_spa
, 0, &lwb
->lwb_blk
, lwb_abd
,
1431 BP_GET_LSIZE(&lwb
->lwb_blk
), zil_lwb_write_done
, lwb
,
1432 prio
, ZIO_FLAG_CANFAIL
| ZIO_FLAG_FASTWRITE
, &zb
);
1433 ASSERT3P(lwb
->lwb_write_zio
, !=, NULL
);
1435 lwb
->lwb_state
= LWB_STATE_OPENED
;
1437 zil_lwb_set_zio_dependency(zilog
, lwb
);
1438 zilog
->zl_last_lwb_opened
= lwb
;
1440 mutex_exit(&zilog
->zl_lock
);
1442 ASSERT3P(lwb
->lwb_root_zio
, !=, NULL
);
1443 ASSERT3P(lwb
->lwb_write_zio
, !=, NULL
);
1444 ASSERT3S(lwb
->lwb_state
, ==, LWB_STATE_OPENED
);
1448 * Define a limited set of intent log block sizes.
1450 * These must be a multiple of 4KB. Note only the amount used (again
1451 * aligned to 4KB) actually gets written. However, we can't always just
1452 * allocate SPA_OLD_MAXBLOCKSIZE as the slog space could be exhausted.
1454 static const struct {
1457 } zil_block_buckets
[] = {
1458 { 4096, 4096 }, /* non TX_WRITE */
1459 { 8192 + 4096, 8192 + 4096 }, /* database */
1460 { 32768 + 4096, 32768 + 4096 }, /* NFS writes */
1461 { 65536 + 4096, 65536 + 4096 }, /* 64KB writes */
1462 { 131072, 131072 }, /* < 128KB writes */
1463 { 131072 +4096, 65536 + 4096 }, /* 128KB writes */
1464 { UINT64_MAX
, SPA_OLD_MAXBLOCKSIZE
}, /* > 128KB writes */
1468 * Maximum block size used by the ZIL. This is picked up when the ZIL is
1469 * initialized. Otherwise this should not be used directly; see
1470 * zl_max_block_size instead.
1472 static int zil_maxblocksize
= SPA_OLD_MAXBLOCKSIZE
;
1475 * Start a log block write and advance to the next log block.
1476 * Calls are serialized.
1479 zil_lwb_write_issue(zilog_t
*zilog
, lwb_t
*lwb
)
1483 spa_t
*spa
= zilog
->zl_spa
;
1487 uint64_t zil_blksz
, wsz
;
1491 ASSERT(MUTEX_HELD(&zilog
->zl_issuer_lock
));
1492 ASSERT3P(lwb
->lwb_root_zio
, !=, NULL
);
1493 ASSERT3P(lwb
->lwb_write_zio
, !=, NULL
);
1494 ASSERT3S(lwb
->lwb_state
, ==, LWB_STATE_OPENED
);
1496 if (BP_GET_CHECKSUM(&lwb
->lwb_blk
) == ZIO_CHECKSUM_ZILOG2
) {
1497 zilc
= (zil_chain_t
*)lwb
->lwb_buf
;
1498 bp
= &zilc
->zc_next_blk
;
1500 zilc
= (zil_chain_t
*)(lwb
->lwb_buf
+ lwb
->lwb_sz
);
1501 bp
= &zilc
->zc_next_blk
;
1504 ASSERT(lwb
->lwb_nused
<= lwb
->lwb_sz
);
1507 * Allocate the next block and save its address in this block
1508 * before writing it in order to establish the log chain.
1509 * Note that if the allocation of nlwb synced before we wrote
1510 * the block that points at it (lwb), we'd leak it if we crashed.
1511 * Therefore, we don't do dmu_tx_commit() until zil_lwb_write_done().
1512 * We dirty the dataset to ensure that zil_sync() will be called
1513 * to clean up in the event of allocation failure or I/O failure.
1516 tx
= dmu_tx_create(zilog
->zl_os
);
1519 * Since we are not going to create any new dirty data, and we
1520 * can even help with clearing the existing dirty data, we
1521 * should not be subject to the dirty data based delays. We
1522 * use TXG_NOTHROTTLE to bypass the delay mechanism.
1524 VERIFY0(dmu_tx_assign(tx
, TXG_WAIT
| TXG_NOTHROTTLE
));
1526 dsl_dataset_dirty(dmu_objset_ds(zilog
->zl_os
), tx
);
1527 txg
= dmu_tx_get_txg(tx
);
1532 * Log blocks are pre-allocated. Here we select the size of the next
1533 * block, based on size used in the last block.
1534 * - first find the smallest bucket that will fit the block from a
1535 * limited set of block sizes. This is because it's faster to write
1536 * blocks allocated from the same metaslab as they are adjacent or
1538 * - next find the maximum from the new suggested size and an array of
1539 * previous sizes. This lessens a picket fence effect of wrongly
1540 * guessing the size if we have a stream of say 2k, 64k, 2k, 64k
1543 * Note we only write what is used, but we can't just allocate
1544 * the maximum block size because we can exhaust the available
1547 zil_blksz
= zilog
->zl_cur_used
+ sizeof (zil_chain_t
);
1548 for (i
= 0; zil_blksz
> zil_block_buckets
[i
].limit
; i
++)
1550 zil_blksz
= MIN(zil_block_buckets
[i
].blksz
, zilog
->zl_max_block_size
);
1551 zilog
->zl_prev_blks
[zilog
->zl_prev_rotor
] = zil_blksz
;
1552 for (i
= 0; i
< ZIL_PREV_BLKS
; i
++)
1553 zil_blksz
= MAX(zil_blksz
, zilog
->zl_prev_blks
[i
]);
1554 zilog
->zl_prev_rotor
= (zilog
->zl_prev_rotor
+ 1) & (ZIL_PREV_BLKS
- 1);
1557 error
= zio_alloc_zil(spa
, zilog
->zl_os
, txg
, bp
, zil_blksz
, &slog
);
1559 ZIL_STAT_BUMP(zil_itx_metaslab_slog_count
);
1560 ZIL_STAT_INCR(zil_itx_metaslab_slog_bytes
, lwb
->lwb_nused
);
1562 ZIL_STAT_BUMP(zil_itx_metaslab_normal_count
);
1563 ZIL_STAT_INCR(zil_itx_metaslab_normal_bytes
, lwb
->lwb_nused
);
1566 ASSERT3U(bp
->blk_birth
, ==, txg
);
1567 bp
->blk_cksum
= lwb
->lwb_blk
.blk_cksum
;
1568 bp
->blk_cksum
.zc_word
[ZIL_ZC_SEQ
]++;
1571 * Allocate a new log write block (lwb).
1573 nlwb
= zil_alloc_lwb(zilog
, bp
, slog
, txg
, TRUE
);
1576 if (BP_GET_CHECKSUM(&lwb
->lwb_blk
) == ZIO_CHECKSUM_ZILOG2
) {
1577 /* For Slim ZIL only write what is used. */
1578 wsz
= P2ROUNDUP_TYPED(lwb
->lwb_nused
, ZIL_MIN_BLKSZ
, uint64_t);
1579 ASSERT3U(wsz
, <=, lwb
->lwb_sz
);
1580 zio_shrink(lwb
->lwb_write_zio
, wsz
);
1587 zilc
->zc_nused
= lwb
->lwb_nused
;
1588 zilc
->zc_eck
.zec_cksum
= lwb
->lwb_blk
.blk_cksum
;
1591 * clear unused data for security
1593 bzero(lwb
->lwb_buf
+ lwb
->lwb_nused
, wsz
- lwb
->lwb_nused
);
1595 spa_config_enter(zilog
->zl_spa
, SCL_STATE
, lwb
, RW_READER
);
1597 zil_lwb_add_block(lwb
, &lwb
->lwb_blk
);
1598 lwb
->lwb_issued_timestamp
= gethrtime();
1599 lwb
->lwb_state
= LWB_STATE_ISSUED
;
1601 zio_nowait(lwb
->lwb_root_zio
);
1602 zio_nowait(lwb
->lwb_write_zio
);
1605 * If there was an allocation failure then nlwb will be null which
1606 * forces a txg_wait_synced().
1612 * Maximum amount of write data that can be put into single log block.
1615 zil_max_log_data(zilog_t
*zilog
)
1617 return (zilog
->zl_max_block_size
-
1618 sizeof (zil_chain_t
) - sizeof (lr_write_t
));
1622 * Maximum amount of log space we agree to waste to reduce number of
1623 * WR_NEED_COPY chunks to reduce zl_get_data() overhead (~12%).
1625 static inline uint64_t
1626 zil_max_waste_space(zilog_t
*zilog
)
1628 return (zil_max_log_data(zilog
) / 8);
1632 * Maximum amount of write data for WR_COPIED. For correctness, consumers
1633 * must fall back to WR_NEED_COPY if we can't fit the entire record into one
1634 * maximum sized log block, because each WR_COPIED record must fit in a
1635 * single log block. For space efficiency, we want to fit two records into a
1636 * max-sized log block.
1639 zil_max_copied_data(zilog_t
*zilog
)
1641 return ((zilog
->zl_max_block_size
- sizeof (zil_chain_t
)) / 2 -
1642 sizeof (lr_write_t
));
1646 zil_lwb_commit(zilog_t
*zilog
, itx_t
*itx
, lwb_t
*lwb
)
1649 lr_write_t
*lrwb
, *lrw
;
1651 uint64_t dlen
, dnow
, dpad
, lwb_sp
, reclen
, txg
, max_log_data
;
1653 ASSERT(MUTEX_HELD(&zilog
->zl_issuer_lock
));
1654 ASSERT3P(lwb
, !=, NULL
);
1655 ASSERT3P(lwb
->lwb_buf
, !=, NULL
);
1657 zil_lwb_write_open(zilog
, lwb
);
1660 lrw
= (lr_write_t
*)lrc
;
1663 * A commit itx doesn't represent any on-disk state; instead
1664 * it's simply used as a place holder on the commit list, and
1665 * provides a mechanism for attaching a "commit waiter" onto the
1666 * correct lwb (such that the waiter can be signalled upon
1667 * completion of that lwb). Thus, we don't process this itx's
1668 * log record if it's a commit itx (these itx's don't have log
1669 * records), and instead link the itx's waiter onto the lwb's
1672 * For more details, see the comment above zil_commit().
1674 if (lrc
->lrc_txtype
== TX_COMMIT
) {
1675 mutex_enter(&zilog
->zl_lock
);
1676 zil_commit_waiter_link_lwb(itx
->itx_private
, lwb
);
1677 itx
->itx_private
= NULL
;
1678 mutex_exit(&zilog
->zl_lock
);
1682 if (lrc
->lrc_txtype
== TX_WRITE
&& itx
->itx_wr_state
== WR_NEED_COPY
) {
1683 dlen
= P2ROUNDUP_TYPED(
1684 lrw
->lr_length
, sizeof (uint64_t), uint64_t);
1685 dpad
= dlen
- lrw
->lr_length
;
1689 reclen
= lrc
->lrc_reclen
;
1690 zilog
->zl_cur_used
+= (reclen
+ dlen
);
1693 ASSERT3U(zilog
->zl_cur_used
, <, UINT64_MAX
- (reclen
+ dlen
));
1697 * If this record won't fit in the current log block, start a new one.
1698 * For WR_NEED_COPY optimize layout for minimal number of chunks.
1700 lwb_sp
= lwb
->lwb_sz
- lwb
->lwb_nused
;
1701 max_log_data
= zil_max_log_data(zilog
);
1702 if (reclen
> lwb_sp
|| (reclen
+ dlen
> lwb_sp
&&
1703 lwb_sp
< zil_max_waste_space(zilog
) &&
1704 (dlen
% max_log_data
== 0 ||
1705 lwb_sp
< reclen
+ dlen
% max_log_data
))) {
1706 lwb
= zil_lwb_write_issue(zilog
, lwb
);
1709 zil_lwb_write_open(zilog
, lwb
);
1710 ASSERT(LWB_EMPTY(lwb
));
1711 lwb_sp
= lwb
->lwb_sz
- lwb
->lwb_nused
;
1714 * There must be enough space in the new, empty log block to
1715 * hold reclen. For WR_COPIED, we need to fit the whole
1716 * record in one block, and reclen is the header size + the
1717 * data size. For WR_NEED_COPY, we can create multiple
1718 * records, splitting the data into multiple blocks, so we
1719 * only need to fit one word of data per block; in this case
1720 * reclen is just the header size (no data).
1722 ASSERT3U(reclen
+ MIN(dlen
, sizeof (uint64_t)), <=, lwb_sp
);
1725 dnow
= MIN(dlen
, lwb_sp
- reclen
);
1726 lr_buf
= lwb
->lwb_buf
+ lwb
->lwb_nused
;
1727 bcopy(lrc
, lr_buf
, reclen
);
1728 lrcb
= (lr_t
*)lr_buf
; /* Like lrc, but inside lwb. */
1729 lrwb
= (lr_write_t
*)lrcb
; /* Like lrw, but inside lwb. */
1731 ZIL_STAT_BUMP(zil_itx_count
);
1734 * If it's a write, fetch the data or get its blkptr as appropriate.
1736 if (lrc
->lrc_txtype
== TX_WRITE
) {
1737 if (txg
> spa_freeze_txg(zilog
->zl_spa
))
1738 txg_wait_synced(zilog
->zl_dmu_pool
, txg
);
1739 if (itx
->itx_wr_state
== WR_COPIED
) {
1740 ZIL_STAT_BUMP(zil_itx_copied_count
);
1741 ZIL_STAT_INCR(zil_itx_copied_bytes
, lrw
->lr_length
);
1746 if (itx
->itx_wr_state
== WR_NEED_COPY
) {
1747 dbuf
= lr_buf
+ reclen
;
1748 lrcb
->lrc_reclen
+= dnow
;
1749 if (lrwb
->lr_length
> dnow
)
1750 lrwb
->lr_length
= dnow
;
1751 lrw
->lr_offset
+= dnow
;
1752 lrw
->lr_length
-= dnow
;
1753 ZIL_STAT_BUMP(zil_itx_needcopy_count
);
1754 ZIL_STAT_INCR(zil_itx_needcopy_bytes
, dnow
);
1756 ASSERT3S(itx
->itx_wr_state
, ==, WR_INDIRECT
);
1758 ZIL_STAT_BUMP(zil_itx_indirect_count
);
1759 ZIL_STAT_INCR(zil_itx_indirect_bytes
,
1764 * We pass in the "lwb_write_zio" rather than
1765 * "lwb_root_zio" so that the "lwb_write_zio"
1766 * becomes the parent of any zio's created by
1767 * the "zl_get_data" callback. The vdevs are
1768 * flushed after the "lwb_write_zio" completes,
1769 * so we want to make sure that completion
1770 * callback waits for these additional zio's,
1771 * such that the vdevs used by those zio's will
1772 * be included in the lwb's vdev tree, and those
1773 * vdevs will be properly flushed. If we passed
1774 * in "lwb_root_zio" here, then these additional
1775 * vdevs may not be flushed; e.g. if these zio's
1776 * completed after "lwb_write_zio" completed.
1778 error
= zilog
->zl_get_data(itx
->itx_private
,
1779 itx
->itx_gen
, lrwb
, dbuf
, lwb
,
1780 lwb
->lwb_write_zio
);
1781 if (dbuf
!= NULL
&& error
== 0 && dnow
== dlen
)
1782 /* Zero any padding bytes in the last block. */
1783 bzero((char *)dbuf
+ lrwb
->lr_length
, dpad
);
1786 txg_wait_synced(zilog
->zl_dmu_pool
, txg
);
1790 ASSERT(error
== ENOENT
|| error
== EEXIST
||
1798 * We're actually making an entry, so update lrc_seq to be the
1799 * log record sequence number. Note that this is generally not
1800 * equal to the itx sequence number because not all transactions
1801 * are synchronous, and sometimes spa_sync() gets there first.
1803 lrcb
->lrc_seq
= ++zilog
->zl_lr_seq
;
1804 lwb
->lwb_nused
+= reclen
+ dnow
;
1806 zil_lwb_add_txg(lwb
, txg
);
1808 ASSERT3U(lwb
->lwb_nused
, <=, lwb
->lwb_sz
);
1809 ASSERT0(P2PHASE(lwb
->lwb_nused
, sizeof (uint64_t)));
1813 zilog
->zl_cur_used
+= reclen
;
1821 zil_itx_create(uint64_t txtype
, size_t olrsize
)
1823 size_t itxsize
, lrsize
;
1826 lrsize
= P2ROUNDUP_TYPED(olrsize
, sizeof (uint64_t), size_t);
1827 itxsize
= offsetof(itx_t
, itx_lr
) + lrsize
;
1829 itx
= zio_data_buf_alloc(itxsize
);
1830 itx
->itx_lr
.lrc_txtype
= txtype
;
1831 itx
->itx_lr
.lrc_reclen
= lrsize
;
1832 itx
->itx_lr
.lrc_seq
= 0; /* defensive */
1833 bzero((char *)&itx
->itx_lr
+ olrsize
, lrsize
- olrsize
);
1834 itx
->itx_sync
= B_TRUE
; /* default is synchronous */
1835 itx
->itx_callback
= NULL
;
1836 itx
->itx_callback_data
= NULL
;
1837 itx
->itx_size
= itxsize
;
1843 zil_itx_destroy(itx_t
*itx
)
1845 IMPLY(itx
->itx_lr
.lrc_txtype
== TX_COMMIT
, itx
->itx_callback
== NULL
);
1846 IMPLY(itx
->itx_callback
!= NULL
, itx
->itx_lr
.lrc_txtype
!= TX_COMMIT
);
1848 if (itx
->itx_callback
!= NULL
)
1849 itx
->itx_callback(itx
->itx_callback_data
);
1851 zio_data_buf_free(itx
, itx
->itx_size
);
1855 * Free up the sync and async itxs. The itxs_t has already been detached
1856 * so no locks are needed.
1859 zil_itxg_clean(void *arg
)
1866 itx_async_node_t
*ian
;
1868 list
= &itxs
->i_sync_list
;
1869 while ((itx
= list_head(list
)) != NULL
) {
1871 * In the general case, commit itxs will not be found
1872 * here, as they'll be committed to an lwb via
1873 * zil_lwb_commit(), and free'd in that function. Having
1874 * said that, it is still possible for commit itxs to be
1875 * found here, due to the following race:
1877 * - a thread calls zil_commit() which assigns the
1878 * commit itx to a per-txg i_sync_list
1879 * - zil_itxg_clean() is called (e.g. via spa_sync())
1880 * while the waiter is still on the i_sync_list
1882 * There's nothing to prevent syncing the txg while the
1883 * waiter is on the i_sync_list. This normally doesn't
1884 * happen because spa_sync() is slower than zil_commit(),
1885 * but if zil_commit() calls txg_wait_synced() (e.g.
1886 * because zil_create() or zil_commit_writer_stall() is
1887 * called) we will hit this case.
1889 if (itx
->itx_lr
.lrc_txtype
== TX_COMMIT
)
1890 zil_commit_waiter_skip(itx
->itx_private
);
1892 list_remove(list
, itx
);
1893 zil_itx_destroy(itx
);
1897 t
= &itxs
->i_async_tree
;
1898 while ((ian
= avl_destroy_nodes(t
, &cookie
)) != NULL
) {
1899 list
= &ian
->ia_list
;
1900 while ((itx
= list_head(list
)) != NULL
) {
1901 list_remove(list
, itx
);
1902 /* commit itxs should never be on the async lists. */
1903 ASSERT3U(itx
->itx_lr
.lrc_txtype
, !=, TX_COMMIT
);
1904 zil_itx_destroy(itx
);
1907 kmem_free(ian
, sizeof (itx_async_node_t
));
1911 kmem_free(itxs
, sizeof (itxs_t
));
1915 zil_aitx_compare(const void *x1
, const void *x2
)
1917 const uint64_t o1
= ((itx_async_node_t
*)x1
)->ia_foid
;
1918 const uint64_t o2
= ((itx_async_node_t
*)x2
)->ia_foid
;
1920 return (TREE_CMP(o1
, o2
));
1924 * Remove all async itx with the given oid.
1927 zil_remove_async(zilog_t
*zilog
, uint64_t oid
)
1930 itx_async_node_t
*ian
;
1937 list_create(&clean_list
, sizeof (itx_t
), offsetof(itx_t
, itx_node
));
1939 if (spa_freeze_txg(zilog
->zl_spa
) != UINT64_MAX
) /* ziltest support */
1942 otxg
= spa_last_synced_txg(zilog
->zl_spa
) + 1;
1944 for (txg
= otxg
; txg
< (otxg
+ TXG_CONCURRENT_STATES
); txg
++) {
1945 itxg_t
*itxg
= &zilog
->zl_itxg
[txg
& TXG_MASK
];
1947 mutex_enter(&itxg
->itxg_lock
);
1948 if (itxg
->itxg_txg
!= txg
) {
1949 mutex_exit(&itxg
->itxg_lock
);
1954 * Locate the object node and append its list.
1956 t
= &itxg
->itxg_itxs
->i_async_tree
;
1957 ian
= avl_find(t
, &oid
, &where
);
1959 list_move_tail(&clean_list
, &ian
->ia_list
);
1960 mutex_exit(&itxg
->itxg_lock
);
1962 while ((itx
= list_head(&clean_list
)) != NULL
) {
1963 list_remove(&clean_list
, itx
);
1964 /* commit itxs should never be on the async lists. */
1965 ASSERT3U(itx
->itx_lr
.lrc_txtype
, !=, TX_COMMIT
);
1966 zil_itx_destroy(itx
);
1968 list_destroy(&clean_list
);
1972 zil_itx_assign(zilog_t
*zilog
, itx_t
*itx
, dmu_tx_t
*tx
)
1976 itxs_t
*itxs
, *clean
= NULL
;
1979 * Ensure the data of a renamed file is committed before the rename.
1981 if ((itx
->itx_lr
.lrc_txtype
& ~TX_CI
) == TX_RENAME
)
1982 zil_async_to_sync(zilog
, itx
->itx_oid
);
1984 if (spa_freeze_txg(zilog
->zl_spa
) != UINT64_MAX
)
1987 txg
= dmu_tx_get_txg(tx
);
1989 itxg
= &zilog
->zl_itxg
[txg
& TXG_MASK
];
1990 mutex_enter(&itxg
->itxg_lock
);
1991 itxs
= itxg
->itxg_itxs
;
1992 if (itxg
->itxg_txg
!= txg
) {
1995 * The zil_clean callback hasn't got around to cleaning
1996 * this itxg. Save the itxs for release below.
1997 * This should be rare.
1999 zfs_dbgmsg("zil_itx_assign: missed itx cleanup for "
2000 "txg %llu", (u_longlong_t
)itxg
->itxg_txg
);
2001 clean
= itxg
->itxg_itxs
;
2003 itxg
->itxg_txg
= txg
;
2004 itxs
= itxg
->itxg_itxs
= kmem_zalloc(sizeof (itxs_t
),
2007 list_create(&itxs
->i_sync_list
, sizeof (itx_t
),
2008 offsetof(itx_t
, itx_node
));
2009 avl_create(&itxs
->i_async_tree
, zil_aitx_compare
,
2010 sizeof (itx_async_node_t
),
2011 offsetof(itx_async_node_t
, ia_node
));
2013 if (itx
->itx_sync
) {
2014 list_insert_tail(&itxs
->i_sync_list
, itx
);
2016 avl_tree_t
*t
= &itxs
->i_async_tree
;
2018 LR_FOID_GET_OBJ(((lr_ooo_t
*)&itx
->itx_lr
)->lr_foid
);
2019 itx_async_node_t
*ian
;
2022 ian
= avl_find(t
, &foid
, &where
);
2024 ian
= kmem_alloc(sizeof (itx_async_node_t
),
2026 list_create(&ian
->ia_list
, sizeof (itx_t
),
2027 offsetof(itx_t
, itx_node
));
2028 ian
->ia_foid
= foid
;
2029 avl_insert(t
, ian
, where
);
2031 list_insert_tail(&ian
->ia_list
, itx
);
2034 itx
->itx_lr
.lrc_txg
= dmu_tx_get_txg(tx
);
2037 * We don't want to dirty the ZIL using ZILTEST_TXG, because
2038 * zil_clean() will never be called using ZILTEST_TXG. Thus, we
2039 * need to be careful to always dirty the ZIL using the "real"
2040 * TXG (not itxg_txg) even when the SPA is frozen.
2042 zilog_dirty(zilog
, dmu_tx_get_txg(tx
));
2043 mutex_exit(&itxg
->itxg_lock
);
2045 /* Release the old itxs now we've dropped the lock */
2047 zil_itxg_clean(clean
);
2051 * If there are any in-memory intent log transactions which have now been
2052 * synced then start up a taskq to free them. We should only do this after we
2053 * have written out the uberblocks (i.e. txg has been committed) so that
2054 * don't inadvertently clean out in-memory log records that would be required
2058 zil_clean(zilog_t
*zilog
, uint64_t synced_txg
)
2060 itxg_t
*itxg
= &zilog
->zl_itxg
[synced_txg
& TXG_MASK
];
2063 ASSERT3U(synced_txg
, <, ZILTEST_TXG
);
2065 mutex_enter(&itxg
->itxg_lock
);
2066 if (itxg
->itxg_itxs
== NULL
|| itxg
->itxg_txg
== ZILTEST_TXG
) {
2067 mutex_exit(&itxg
->itxg_lock
);
2070 ASSERT3U(itxg
->itxg_txg
, <=, synced_txg
);
2071 ASSERT3U(itxg
->itxg_txg
, !=, 0);
2072 clean_me
= itxg
->itxg_itxs
;
2073 itxg
->itxg_itxs
= NULL
;
2075 mutex_exit(&itxg
->itxg_lock
);
2077 * Preferably start a task queue to free up the old itxs but
2078 * if taskq_dispatch can't allocate resources to do that then
2079 * free it in-line. This should be rare. Note, using TQ_SLEEP
2080 * created a bad performance problem.
2082 ASSERT3P(zilog
->zl_dmu_pool
, !=, NULL
);
2083 ASSERT3P(zilog
->zl_dmu_pool
->dp_zil_clean_taskq
, !=, NULL
);
2084 taskqid_t id
= taskq_dispatch(zilog
->zl_dmu_pool
->dp_zil_clean_taskq
,
2085 zil_itxg_clean
, clean_me
, TQ_NOSLEEP
);
2086 if (id
== TASKQID_INVALID
)
2087 zil_itxg_clean(clean_me
);
2091 * This function will traverse the queue of itxs that need to be
2092 * committed, and move them onto the ZIL's zl_itx_commit_list.
2095 zil_get_commit_list(zilog_t
*zilog
)
2098 list_t
*commit_list
= &zilog
->zl_itx_commit_list
;
2100 ASSERT(MUTEX_HELD(&zilog
->zl_issuer_lock
));
2102 if (spa_freeze_txg(zilog
->zl_spa
) != UINT64_MAX
) /* ziltest support */
2105 otxg
= spa_last_synced_txg(zilog
->zl_spa
) + 1;
2108 * This is inherently racy, since there is nothing to prevent
2109 * the last synced txg from changing. That's okay since we'll
2110 * only commit things in the future.
2112 for (txg
= otxg
; txg
< (otxg
+ TXG_CONCURRENT_STATES
); txg
++) {
2113 itxg_t
*itxg
= &zilog
->zl_itxg
[txg
& TXG_MASK
];
2115 mutex_enter(&itxg
->itxg_lock
);
2116 if (itxg
->itxg_txg
!= txg
) {
2117 mutex_exit(&itxg
->itxg_lock
);
2122 * If we're adding itx records to the zl_itx_commit_list,
2123 * then the zil better be dirty in this "txg". We can assert
2124 * that here since we're holding the itxg_lock which will
2125 * prevent spa_sync from cleaning it. Once we add the itxs
2126 * to the zl_itx_commit_list we must commit it to disk even
2127 * if it's unnecessary (i.e. the txg was synced).
2129 ASSERT(zilog_is_dirty_in_txg(zilog
, txg
) ||
2130 spa_freeze_txg(zilog
->zl_spa
) != UINT64_MAX
);
2131 list_move_tail(commit_list
, &itxg
->itxg_itxs
->i_sync_list
);
2133 mutex_exit(&itxg
->itxg_lock
);
2138 * Move the async itxs for a specified object to commit into sync lists.
2141 zil_async_to_sync(zilog_t
*zilog
, uint64_t foid
)
2144 itx_async_node_t
*ian
;
2148 if (spa_freeze_txg(zilog
->zl_spa
) != UINT64_MAX
) /* ziltest support */
2151 otxg
= spa_last_synced_txg(zilog
->zl_spa
) + 1;
2154 * This is inherently racy, since there is nothing to prevent
2155 * the last synced txg from changing.
2157 for (txg
= otxg
; txg
< (otxg
+ TXG_CONCURRENT_STATES
); txg
++) {
2158 itxg_t
*itxg
= &zilog
->zl_itxg
[txg
& TXG_MASK
];
2160 mutex_enter(&itxg
->itxg_lock
);
2161 if (itxg
->itxg_txg
!= txg
) {
2162 mutex_exit(&itxg
->itxg_lock
);
2167 * If a foid is specified then find that node and append its
2168 * list. Otherwise walk the tree appending all the lists
2169 * to the sync list. We add to the end rather than the
2170 * beginning to ensure the create has happened.
2172 t
= &itxg
->itxg_itxs
->i_async_tree
;
2174 ian
= avl_find(t
, &foid
, &where
);
2176 list_move_tail(&itxg
->itxg_itxs
->i_sync_list
,
2180 void *cookie
= NULL
;
2182 while ((ian
= avl_destroy_nodes(t
, &cookie
)) != NULL
) {
2183 list_move_tail(&itxg
->itxg_itxs
->i_sync_list
,
2185 list_destroy(&ian
->ia_list
);
2186 kmem_free(ian
, sizeof (itx_async_node_t
));
2189 mutex_exit(&itxg
->itxg_lock
);
2194 * This function will prune commit itxs that are at the head of the
2195 * commit list (it won't prune past the first non-commit itx), and
2196 * either: a) attach them to the last lwb that's still pending
2197 * completion, or b) skip them altogether.
2199 * This is used as a performance optimization to prevent commit itxs
2200 * from generating new lwbs when it's unnecessary to do so.
2203 zil_prune_commit_list(zilog_t
*zilog
)
2207 ASSERT(MUTEX_HELD(&zilog
->zl_issuer_lock
));
2209 while ((itx
= list_head(&zilog
->zl_itx_commit_list
)) != NULL
) {
2210 lr_t
*lrc
= &itx
->itx_lr
;
2211 if (lrc
->lrc_txtype
!= TX_COMMIT
)
2214 mutex_enter(&zilog
->zl_lock
);
2216 lwb_t
*last_lwb
= zilog
->zl_last_lwb_opened
;
2217 if (last_lwb
== NULL
||
2218 last_lwb
->lwb_state
== LWB_STATE_FLUSH_DONE
) {
2220 * All of the itxs this waiter was waiting on
2221 * must have already completed (or there were
2222 * never any itx's for it to wait on), so it's
2223 * safe to skip this waiter and mark it done.
2225 zil_commit_waiter_skip(itx
->itx_private
);
2227 zil_commit_waiter_link_lwb(itx
->itx_private
, last_lwb
);
2228 itx
->itx_private
= NULL
;
2231 mutex_exit(&zilog
->zl_lock
);
2233 list_remove(&zilog
->zl_itx_commit_list
, itx
);
2234 zil_itx_destroy(itx
);
2237 IMPLY(itx
!= NULL
, itx
->itx_lr
.lrc_txtype
!= TX_COMMIT
);
2241 zil_commit_writer_stall(zilog_t
*zilog
)
2244 * When zio_alloc_zil() fails to allocate the next lwb block on
2245 * disk, we must call txg_wait_synced() to ensure all of the
2246 * lwbs in the zilog's zl_lwb_list are synced and then freed (in
2247 * zil_sync()), such that any subsequent ZIL writer (i.e. a call
2248 * to zil_process_commit_list()) will have to call zil_create(),
2249 * and start a new ZIL chain.
2251 * Since zil_alloc_zil() failed, the lwb that was previously
2252 * issued does not have a pointer to the "next" lwb on disk.
2253 * Thus, if another ZIL writer thread was to allocate the "next"
2254 * on-disk lwb, that block could be leaked in the event of a
2255 * crash (because the previous lwb on-disk would not point to
2258 * We must hold the zilog's zl_issuer_lock while we do this, to
2259 * ensure no new threads enter zil_process_commit_list() until
2260 * all lwb's in the zl_lwb_list have been synced and freed
2261 * (which is achieved via the txg_wait_synced() call).
2263 ASSERT(MUTEX_HELD(&zilog
->zl_issuer_lock
));
2264 txg_wait_synced(zilog
->zl_dmu_pool
, 0);
2265 ASSERT3P(list_tail(&zilog
->zl_lwb_list
), ==, NULL
);
2269 * This function will traverse the commit list, creating new lwbs as
2270 * needed, and committing the itxs from the commit list to these newly
2271 * created lwbs. Additionally, as a new lwb is created, the previous
2272 * lwb will be issued to the zio layer to be written to disk.
2275 zil_process_commit_list(zilog_t
*zilog
)
2277 spa_t
*spa
= zilog
->zl_spa
;
2279 list_t nolwb_waiters
;
2283 ASSERT(MUTEX_HELD(&zilog
->zl_issuer_lock
));
2286 * Return if there's nothing to commit before we dirty the fs by
2287 * calling zil_create().
2289 if (list_head(&zilog
->zl_itx_commit_list
) == NULL
)
2292 list_create(&nolwb_itxs
, sizeof (itx_t
), offsetof(itx_t
, itx_node
));
2293 list_create(&nolwb_waiters
, sizeof (zil_commit_waiter_t
),
2294 offsetof(zil_commit_waiter_t
, zcw_node
));
2296 lwb
= list_tail(&zilog
->zl_lwb_list
);
2298 lwb
= zil_create(zilog
);
2300 ASSERT3S(lwb
->lwb_state
, !=, LWB_STATE_ISSUED
);
2301 ASSERT3S(lwb
->lwb_state
, !=, LWB_STATE_WRITE_DONE
);
2302 ASSERT3S(lwb
->lwb_state
, !=, LWB_STATE_FLUSH_DONE
);
2305 while ((itx
= list_head(&zilog
->zl_itx_commit_list
)) != NULL
) {
2306 lr_t
*lrc
= &itx
->itx_lr
;
2307 uint64_t txg
= lrc
->lrc_txg
;
2309 ASSERT3U(txg
, !=, 0);
2311 if (lrc
->lrc_txtype
== TX_COMMIT
) {
2312 DTRACE_PROBE2(zil__process__commit__itx
,
2313 zilog_t
*, zilog
, itx_t
*, itx
);
2315 DTRACE_PROBE2(zil__process__normal__itx
,
2316 zilog_t
*, zilog
, itx_t
*, itx
);
2319 list_remove(&zilog
->zl_itx_commit_list
, itx
);
2321 boolean_t synced
= txg
<= spa_last_synced_txg(spa
);
2322 boolean_t frozen
= txg
> spa_freeze_txg(spa
);
2325 * If the txg of this itx has already been synced out, then
2326 * we don't need to commit this itx to an lwb. This is
2327 * because the data of this itx will have already been
2328 * written to the main pool. This is inherently racy, and
2329 * it's still ok to commit an itx whose txg has already
2330 * been synced; this will result in a write that's
2331 * unnecessary, but will do no harm.
2333 * With that said, we always want to commit TX_COMMIT itxs
2334 * to an lwb, regardless of whether or not that itx's txg
2335 * has been synced out. We do this to ensure any OPENED lwb
2336 * will always have at least one zil_commit_waiter_t linked
2339 * As a counter-example, if we skipped TX_COMMIT itx's
2340 * whose txg had already been synced, the following
2341 * situation could occur if we happened to be racing with
2344 * 1. We commit a non-TX_COMMIT itx to an lwb, where the
2345 * itx's txg is 10 and the last synced txg is 9.
2346 * 2. spa_sync finishes syncing out txg 10.
2347 * 3. We move to the next itx in the list, it's a TX_COMMIT
2348 * whose txg is 10, so we skip it rather than committing
2349 * it to the lwb used in (1).
2351 * If the itx that is skipped in (3) is the last TX_COMMIT
2352 * itx in the commit list, than it's possible for the lwb
2353 * used in (1) to remain in the OPENED state indefinitely.
2355 * To prevent the above scenario from occurring, ensuring
2356 * that once an lwb is OPENED it will transition to ISSUED
2357 * and eventually DONE, we always commit TX_COMMIT itx's to
2358 * an lwb here, even if that itx's txg has already been
2361 * Finally, if the pool is frozen, we _always_ commit the
2362 * itx. The point of freezing the pool is to prevent data
2363 * from being written to the main pool via spa_sync, and
2364 * instead rely solely on the ZIL to persistently store the
2365 * data; i.e. when the pool is frozen, the last synced txg
2366 * value can't be trusted.
2368 if (frozen
|| !synced
|| lrc
->lrc_txtype
== TX_COMMIT
) {
2370 lwb
= zil_lwb_commit(zilog
, itx
, lwb
);
2373 list_insert_tail(&nolwb_itxs
, itx
);
2375 list_insert_tail(&lwb
->lwb_itxs
, itx
);
2377 if (lrc
->lrc_txtype
== TX_COMMIT
) {
2378 zil_commit_waiter_link_nolwb(
2379 itx
->itx_private
, &nolwb_waiters
);
2382 list_insert_tail(&nolwb_itxs
, itx
);
2385 ASSERT3S(lrc
->lrc_txtype
, !=, TX_COMMIT
);
2386 zil_itx_destroy(itx
);
2392 * This indicates zio_alloc_zil() failed to allocate the
2393 * "next" lwb on-disk. When this happens, we must stall
2394 * the ZIL write pipeline; see the comment within
2395 * zil_commit_writer_stall() for more details.
2397 zil_commit_writer_stall(zilog
);
2400 * Additionally, we have to signal and mark the "nolwb"
2401 * waiters as "done" here, since without an lwb, we
2402 * can't do this via zil_lwb_flush_vdevs_done() like
2405 zil_commit_waiter_t
*zcw
;
2406 while ((zcw
= list_head(&nolwb_waiters
)) != NULL
) {
2407 zil_commit_waiter_skip(zcw
);
2408 list_remove(&nolwb_waiters
, zcw
);
2412 * And finally, we have to destroy the itx's that
2413 * couldn't be committed to an lwb; this will also call
2414 * the itx's callback if one exists for the itx.
2416 while ((itx
= list_head(&nolwb_itxs
)) != NULL
) {
2417 list_remove(&nolwb_itxs
, itx
);
2418 zil_itx_destroy(itx
);
2421 ASSERT(list_is_empty(&nolwb_waiters
));
2422 ASSERT3P(lwb
, !=, NULL
);
2423 ASSERT3S(lwb
->lwb_state
, !=, LWB_STATE_ISSUED
);
2424 ASSERT3S(lwb
->lwb_state
, !=, LWB_STATE_WRITE_DONE
);
2425 ASSERT3S(lwb
->lwb_state
, !=, LWB_STATE_FLUSH_DONE
);
2428 * At this point, the ZIL block pointed at by the "lwb"
2429 * variable is in one of the following states: "closed"
2432 * If it's "closed", then no itxs have been committed to
2433 * it, so there's no point in issuing its zio (i.e. it's
2436 * If it's "open", then it contains one or more itxs that
2437 * eventually need to be committed to stable storage. In
2438 * this case we intentionally do not issue the lwb's zio
2439 * to disk yet, and instead rely on one of the following
2440 * two mechanisms for issuing the zio:
2442 * 1. Ideally, there will be more ZIL activity occurring
2443 * on the system, such that this function will be
2444 * immediately called again (not necessarily by the same
2445 * thread) and this lwb's zio will be issued via
2446 * zil_lwb_commit(). This way, the lwb is guaranteed to
2447 * be "full" when it is issued to disk, and we'll make
2448 * use of the lwb's size the best we can.
2450 * 2. If there isn't sufficient ZIL activity occurring on
2451 * the system, such that this lwb's zio isn't issued via
2452 * zil_lwb_commit(), zil_commit_waiter() will issue the
2453 * lwb's zio. If this occurs, the lwb is not guaranteed
2454 * to be "full" by the time its zio is issued, and means
2455 * the size of the lwb was "too large" given the amount
2456 * of ZIL activity occurring on the system at that time.
2458 * We do this for a couple of reasons:
2460 * 1. To try and reduce the number of IOPs needed to
2461 * write the same number of itxs. If an lwb has space
2462 * available in its buffer for more itxs, and more itxs
2463 * will be committed relatively soon (relative to the
2464 * latency of performing a write), then it's beneficial
2465 * to wait for these "next" itxs. This way, more itxs
2466 * can be committed to stable storage with fewer writes.
2468 * 2. To try and use the largest lwb block size that the
2469 * incoming rate of itxs can support. Again, this is to
2470 * try and pack as many itxs into as few lwbs as
2471 * possible, without significantly impacting the latency
2472 * of each individual itx.
2478 * This function is responsible for ensuring the passed in commit waiter
2479 * (and associated commit itx) is committed to an lwb. If the waiter is
2480 * not already committed to an lwb, all itxs in the zilog's queue of
2481 * itxs will be processed. The assumption is the passed in waiter's
2482 * commit itx will found in the queue just like the other non-commit
2483 * itxs, such that when the entire queue is processed, the waiter will
2484 * have been committed to an lwb.
2486 * The lwb associated with the passed in waiter is not guaranteed to
2487 * have been issued by the time this function completes. If the lwb is
2488 * not issued, we rely on future calls to zil_commit_writer() to issue
2489 * the lwb, or the timeout mechanism found in zil_commit_waiter().
2492 zil_commit_writer(zilog_t
*zilog
, zil_commit_waiter_t
*zcw
)
2494 ASSERT(!MUTEX_HELD(&zilog
->zl_lock
));
2495 ASSERT(spa_writeable(zilog
->zl_spa
));
2497 mutex_enter(&zilog
->zl_issuer_lock
);
2499 if (zcw
->zcw_lwb
!= NULL
|| zcw
->zcw_done
) {
2501 * It's possible that, while we were waiting to acquire
2502 * the "zl_issuer_lock", another thread committed this
2503 * waiter to an lwb. If that occurs, we bail out early,
2504 * without processing any of the zilog's queue of itxs.
2506 * On certain workloads and system configurations, the
2507 * "zl_issuer_lock" can become highly contended. In an
2508 * attempt to reduce this contention, we immediately drop
2509 * the lock if the waiter has already been processed.
2511 * We've measured this optimization to reduce CPU spent
2512 * contending on this lock by up to 5%, using a system
2513 * with 32 CPUs, low latency storage (~50 usec writes),
2514 * and 1024 threads performing sync writes.
2519 ZIL_STAT_BUMP(zil_commit_writer_count
);
2521 zil_get_commit_list(zilog
);
2522 zil_prune_commit_list(zilog
);
2523 zil_process_commit_list(zilog
);
2526 mutex_exit(&zilog
->zl_issuer_lock
);
2530 zil_commit_waiter_timeout(zilog_t
*zilog
, zil_commit_waiter_t
*zcw
)
2532 ASSERT(!MUTEX_HELD(&zilog
->zl_issuer_lock
));
2533 ASSERT(MUTEX_HELD(&zcw
->zcw_lock
));
2534 ASSERT3B(zcw
->zcw_done
, ==, B_FALSE
);
2536 lwb_t
*lwb
= zcw
->zcw_lwb
;
2537 ASSERT3P(lwb
, !=, NULL
);
2538 ASSERT3S(lwb
->lwb_state
, !=, LWB_STATE_CLOSED
);
2541 * If the lwb has already been issued by another thread, we can
2542 * immediately return since there's no work to be done (the
2543 * point of this function is to issue the lwb). Additionally, we
2544 * do this prior to acquiring the zl_issuer_lock, to avoid
2545 * acquiring it when it's not necessary to do so.
2547 if (lwb
->lwb_state
== LWB_STATE_ISSUED
||
2548 lwb
->lwb_state
== LWB_STATE_WRITE_DONE
||
2549 lwb
->lwb_state
== LWB_STATE_FLUSH_DONE
)
2553 * In order to call zil_lwb_write_issue() we must hold the
2554 * zilog's "zl_issuer_lock". We can't simply acquire that lock,
2555 * since we're already holding the commit waiter's "zcw_lock",
2556 * and those two locks are acquired in the opposite order
2559 mutex_exit(&zcw
->zcw_lock
);
2560 mutex_enter(&zilog
->zl_issuer_lock
);
2561 mutex_enter(&zcw
->zcw_lock
);
2564 * Since we just dropped and re-acquired the commit waiter's
2565 * lock, we have to re-check to see if the waiter was marked
2566 * "done" during that process. If the waiter was marked "done",
2567 * the "lwb" pointer is no longer valid (it can be free'd after
2568 * the waiter is marked "done"), so without this check we could
2569 * wind up with a use-after-free error below.
2574 ASSERT3P(lwb
, ==, zcw
->zcw_lwb
);
2577 * We've already checked this above, but since we hadn't acquired
2578 * the zilog's zl_issuer_lock, we have to perform this check a
2579 * second time while holding the lock.
2581 * We don't need to hold the zl_lock since the lwb cannot transition
2582 * from OPENED to ISSUED while we hold the zl_issuer_lock. The lwb
2583 * _can_ transition from ISSUED to DONE, but it's OK to race with
2584 * that transition since we treat the lwb the same, whether it's in
2585 * the ISSUED or DONE states.
2587 * The important thing, is we treat the lwb differently depending on
2588 * if it's ISSUED or OPENED, and block any other threads that might
2589 * attempt to issue this lwb. For that reason we hold the
2590 * zl_issuer_lock when checking the lwb_state; we must not call
2591 * zil_lwb_write_issue() if the lwb had already been issued.
2593 * See the comment above the lwb_state_t structure definition for
2594 * more details on the lwb states, and locking requirements.
2596 if (lwb
->lwb_state
== LWB_STATE_ISSUED
||
2597 lwb
->lwb_state
== LWB_STATE_WRITE_DONE
||
2598 lwb
->lwb_state
== LWB_STATE_FLUSH_DONE
)
2601 ASSERT3S(lwb
->lwb_state
, ==, LWB_STATE_OPENED
);
2604 * As described in the comments above zil_commit_waiter() and
2605 * zil_process_commit_list(), we need to issue this lwb's zio
2606 * since we've reached the commit waiter's timeout and it still
2607 * hasn't been issued.
2609 lwb_t
*nlwb
= zil_lwb_write_issue(zilog
, lwb
);
2611 IMPLY(nlwb
!= NULL
, lwb
->lwb_state
!= LWB_STATE_OPENED
);
2614 * Since the lwb's zio hadn't been issued by the time this thread
2615 * reached its timeout, we reset the zilog's "zl_cur_used" field
2616 * to influence the zil block size selection algorithm.
2618 * By having to issue the lwb's zio here, it means the size of the
2619 * lwb was too large, given the incoming throughput of itxs. By
2620 * setting "zl_cur_used" to zero, we communicate this fact to the
2621 * block size selection algorithm, so it can take this information
2622 * into account, and potentially select a smaller size for the
2623 * next lwb block that is allocated.
2625 zilog
->zl_cur_used
= 0;
2629 * When zil_lwb_write_issue() returns NULL, this
2630 * indicates zio_alloc_zil() failed to allocate the
2631 * "next" lwb on-disk. When this occurs, the ZIL write
2632 * pipeline must be stalled; see the comment within the
2633 * zil_commit_writer_stall() function for more details.
2635 * We must drop the commit waiter's lock prior to
2636 * calling zil_commit_writer_stall() or else we can wind
2637 * up with the following deadlock:
2639 * - This thread is waiting for the txg to sync while
2640 * holding the waiter's lock; txg_wait_synced() is
2641 * used within txg_commit_writer_stall().
2643 * - The txg can't sync because it is waiting for this
2644 * lwb's zio callback to call dmu_tx_commit().
2646 * - The lwb's zio callback can't call dmu_tx_commit()
2647 * because it's blocked trying to acquire the waiter's
2648 * lock, which occurs prior to calling dmu_tx_commit()
2650 mutex_exit(&zcw
->zcw_lock
);
2651 zil_commit_writer_stall(zilog
);
2652 mutex_enter(&zcw
->zcw_lock
);
2656 mutex_exit(&zilog
->zl_issuer_lock
);
2657 ASSERT(MUTEX_HELD(&zcw
->zcw_lock
));
2661 * This function is responsible for performing the following two tasks:
2663 * 1. its primary responsibility is to block until the given "commit
2664 * waiter" is considered "done".
2666 * 2. its secondary responsibility is to issue the zio for the lwb that
2667 * the given "commit waiter" is waiting on, if this function has
2668 * waited "long enough" and the lwb is still in the "open" state.
2670 * Given a sufficient amount of itxs being generated and written using
2671 * the ZIL, the lwb's zio will be issued via the zil_lwb_commit()
2672 * function. If this does not occur, this secondary responsibility will
2673 * ensure the lwb is issued even if there is not other synchronous
2674 * activity on the system.
2676 * For more details, see zil_process_commit_list(); more specifically,
2677 * the comment at the bottom of that function.
2680 zil_commit_waiter(zilog_t
*zilog
, zil_commit_waiter_t
*zcw
)
2682 ASSERT(!MUTEX_HELD(&zilog
->zl_lock
));
2683 ASSERT(!MUTEX_HELD(&zilog
->zl_issuer_lock
));
2684 ASSERT(spa_writeable(zilog
->zl_spa
));
2686 mutex_enter(&zcw
->zcw_lock
);
2689 * The timeout is scaled based on the lwb latency to avoid
2690 * significantly impacting the latency of each individual itx.
2691 * For more details, see the comment at the bottom of the
2692 * zil_process_commit_list() function.
2694 int pct
= MAX(zfs_commit_timeout_pct
, 1);
2695 hrtime_t sleep
= (zilog
->zl_last_lwb_latency
* pct
) / 100;
2696 hrtime_t wakeup
= gethrtime() + sleep
;
2697 boolean_t timedout
= B_FALSE
;
2699 while (!zcw
->zcw_done
) {
2700 ASSERT(MUTEX_HELD(&zcw
->zcw_lock
));
2702 lwb_t
*lwb
= zcw
->zcw_lwb
;
2705 * Usually, the waiter will have a non-NULL lwb field here,
2706 * but it's possible for it to be NULL as a result of
2707 * zil_commit() racing with spa_sync().
2709 * When zil_clean() is called, it's possible for the itxg
2710 * list (which may be cleaned via a taskq) to contain
2711 * commit itxs. When this occurs, the commit waiters linked
2712 * off of these commit itxs will not be committed to an
2713 * lwb. Additionally, these commit waiters will not be
2714 * marked done until zil_commit_waiter_skip() is called via
2717 * Thus, it's possible for this commit waiter (i.e. the
2718 * "zcw" variable) to be found in this "in between" state;
2719 * where it's "zcw_lwb" field is NULL, and it hasn't yet
2720 * been skipped, so it's "zcw_done" field is still B_FALSE.
2722 IMPLY(lwb
!= NULL
, lwb
->lwb_state
!= LWB_STATE_CLOSED
);
2724 if (lwb
!= NULL
&& lwb
->lwb_state
== LWB_STATE_OPENED
) {
2725 ASSERT3B(timedout
, ==, B_FALSE
);
2728 * If the lwb hasn't been issued yet, then we
2729 * need to wait with a timeout, in case this
2730 * function needs to issue the lwb after the
2731 * timeout is reached; responsibility (2) from
2732 * the comment above this function.
2734 int rc
= cv_timedwait_hires(&zcw
->zcw_cv
,
2735 &zcw
->zcw_lock
, wakeup
, USEC2NSEC(1),
2736 CALLOUT_FLAG_ABSOLUTE
);
2738 if (rc
!= -1 || zcw
->zcw_done
)
2742 zil_commit_waiter_timeout(zilog
, zcw
);
2744 if (!zcw
->zcw_done
) {
2746 * If the commit waiter has already been
2747 * marked "done", it's possible for the
2748 * waiter's lwb structure to have already
2749 * been freed. Thus, we can only reliably
2750 * make these assertions if the waiter
2753 ASSERT3P(lwb
, ==, zcw
->zcw_lwb
);
2754 ASSERT3S(lwb
->lwb_state
, !=, LWB_STATE_OPENED
);
2758 * If the lwb isn't open, then it must have already
2759 * been issued. In that case, there's no need to
2760 * use a timeout when waiting for the lwb to
2763 * Additionally, if the lwb is NULL, the waiter
2764 * will soon be signaled and marked done via
2765 * zil_clean() and zil_itxg_clean(), so no timeout
2770 lwb
->lwb_state
== LWB_STATE_ISSUED
||
2771 lwb
->lwb_state
== LWB_STATE_WRITE_DONE
||
2772 lwb
->lwb_state
== LWB_STATE_FLUSH_DONE
);
2773 cv_wait(&zcw
->zcw_cv
, &zcw
->zcw_lock
);
2777 mutex_exit(&zcw
->zcw_lock
);
2780 static zil_commit_waiter_t
*
2781 zil_alloc_commit_waiter(void)
2783 zil_commit_waiter_t
*zcw
= kmem_cache_alloc(zil_zcw_cache
, KM_SLEEP
);
2785 cv_init(&zcw
->zcw_cv
, NULL
, CV_DEFAULT
, NULL
);
2786 mutex_init(&zcw
->zcw_lock
, NULL
, MUTEX_DEFAULT
, NULL
);
2787 list_link_init(&zcw
->zcw_node
);
2788 zcw
->zcw_lwb
= NULL
;
2789 zcw
->zcw_done
= B_FALSE
;
2790 zcw
->zcw_zio_error
= 0;
2796 zil_free_commit_waiter(zil_commit_waiter_t
*zcw
)
2798 ASSERT(!list_link_active(&zcw
->zcw_node
));
2799 ASSERT3P(zcw
->zcw_lwb
, ==, NULL
);
2800 ASSERT3B(zcw
->zcw_done
, ==, B_TRUE
);
2801 mutex_destroy(&zcw
->zcw_lock
);
2802 cv_destroy(&zcw
->zcw_cv
);
2803 kmem_cache_free(zil_zcw_cache
, zcw
);
2807 * This function is used to create a TX_COMMIT itx and assign it. This
2808 * way, it will be linked into the ZIL's list of synchronous itxs, and
2809 * then later committed to an lwb (or skipped) when
2810 * zil_process_commit_list() is called.
2813 zil_commit_itx_assign(zilog_t
*zilog
, zil_commit_waiter_t
*zcw
)
2815 dmu_tx_t
*tx
= dmu_tx_create(zilog
->zl_os
);
2816 VERIFY0(dmu_tx_assign(tx
, TXG_WAIT
));
2818 itx_t
*itx
= zil_itx_create(TX_COMMIT
, sizeof (lr_t
));
2819 itx
->itx_sync
= B_TRUE
;
2820 itx
->itx_private
= zcw
;
2822 zil_itx_assign(zilog
, itx
, tx
);
2828 * Commit ZFS Intent Log transactions (itxs) to stable storage.
2830 * When writing ZIL transactions to the on-disk representation of the
2831 * ZIL, the itxs are committed to a Log Write Block (lwb). Multiple
2832 * itxs can be committed to a single lwb. Once a lwb is written and
2833 * committed to stable storage (i.e. the lwb is written, and vdevs have
2834 * been flushed), each itx that was committed to that lwb is also
2835 * considered to be committed to stable storage.
2837 * When an itx is committed to an lwb, the log record (lr_t) contained
2838 * by the itx is copied into the lwb's zio buffer, and once this buffer
2839 * is written to disk, it becomes an on-disk ZIL block.
2841 * As itxs are generated, they're inserted into the ZIL's queue of
2842 * uncommitted itxs. The semantics of zil_commit() are such that it will
2843 * block until all itxs that were in the queue when it was called, are
2844 * committed to stable storage.
2846 * If "foid" is zero, this means all "synchronous" and "asynchronous"
2847 * itxs, for all objects in the dataset, will be committed to stable
2848 * storage prior to zil_commit() returning. If "foid" is non-zero, all
2849 * "synchronous" itxs for all objects, but only "asynchronous" itxs
2850 * that correspond to the foid passed in, will be committed to stable
2851 * storage prior to zil_commit() returning.
2853 * Generally speaking, when zil_commit() is called, the consumer doesn't
2854 * actually care about _all_ of the uncommitted itxs. Instead, they're
2855 * simply trying to waiting for a specific itx to be committed to disk,
2856 * but the interface(s) for interacting with the ZIL don't allow such
2857 * fine-grained communication. A better interface would allow a consumer
2858 * to create and assign an itx, and then pass a reference to this itx to
2859 * zil_commit(); such that zil_commit() would return as soon as that
2860 * specific itx was committed to disk (instead of waiting for _all_
2861 * itxs to be committed).
2863 * When a thread calls zil_commit() a special "commit itx" will be
2864 * generated, along with a corresponding "waiter" for this commit itx.
2865 * zil_commit() will wait on this waiter's CV, such that when the waiter
2866 * is marked done, and signaled, zil_commit() will return.
2868 * This commit itx is inserted into the queue of uncommitted itxs. This
2869 * provides an easy mechanism for determining which itxs were in the
2870 * queue prior to zil_commit() having been called, and which itxs were
2871 * added after zil_commit() was called.
2873 * The commit it is special; it doesn't have any on-disk representation.
2874 * When a commit itx is "committed" to an lwb, the waiter associated
2875 * with it is linked onto the lwb's list of waiters. Then, when that lwb
2876 * completes, each waiter on the lwb's list is marked done and signaled
2877 * -- allowing the thread waiting on the waiter to return from zil_commit().
2879 * It's important to point out a few critical factors that allow us
2880 * to make use of the commit itxs, commit waiters, per-lwb lists of
2881 * commit waiters, and zio completion callbacks like we're doing:
2883 * 1. The list of waiters for each lwb is traversed, and each commit
2884 * waiter is marked "done" and signaled, in the zio completion
2885 * callback of the lwb's zio[*].
2887 * * Actually, the waiters are signaled in the zio completion
2888 * callback of the root zio for the DKIOCFLUSHWRITECACHE commands
2889 * that are sent to the vdevs upon completion of the lwb zio.
2891 * 2. When the itxs are inserted into the ZIL's queue of uncommitted
2892 * itxs, the order in which they are inserted is preserved[*]; as
2893 * itxs are added to the queue, they are added to the tail of
2894 * in-memory linked lists.
2896 * When committing the itxs to lwbs (to be written to disk), they
2897 * are committed in the same order in which the itxs were added to
2898 * the uncommitted queue's linked list(s); i.e. the linked list of
2899 * itxs to commit is traversed from head to tail, and each itx is
2900 * committed to an lwb in that order.
2904 * - the order of "sync" itxs is preserved w.r.t. other
2905 * "sync" itxs, regardless of the corresponding objects.
2906 * - the order of "async" itxs is preserved w.r.t. other
2907 * "async" itxs corresponding to the same object.
2908 * - the order of "async" itxs is *not* preserved w.r.t. other
2909 * "async" itxs corresponding to different objects.
2910 * - the order of "sync" itxs w.r.t. "async" itxs (or vice
2911 * versa) is *not* preserved, even for itxs that correspond
2912 * to the same object.
2914 * For more details, see: zil_itx_assign(), zil_async_to_sync(),
2915 * zil_get_commit_list(), and zil_process_commit_list().
2917 * 3. The lwbs represent a linked list of blocks on disk. Thus, any
2918 * lwb cannot be considered committed to stable storage, until its
2919 * "previous" lwb is also committed to stable storage. This fact,
2920 * coupled with the fact described above, means that itxs are
2921 * committed in (roughly) the order in which they were generated.
2922 * This is essential because itxs are dependent on prior itxs.
2923 * Thus, we *must not* deem an itx as being committed to stable
2924 * storage, until *all* prior itxs have also been committed to
2927 * To enforce this ordering of lwb zio's, while still leveraging as
2928 * much of the underlying storage performance as possible, we rely
2929 * on two fundamental concepts:
2931 * 1. The creation and issuance of lwb zio's is protected by
2932 * the zilog's "zl_issuer_lock", which ensures only a single
2933 * thread is creating and/or issuing lwb's at a time
2934 * 2. The "previous" lwb is a child of the "current" lwb
2935 * (leveraging the zio parent-child dependency graph)
2937 * By relying on this parent-child zio relationship, we can have
2938 * many lwb zio's concurrently issued to the underlying storage,
2939 * but the order in which they complete will be the same order in
2940 * which they were created.
2943 zil_commit(zilog_t
*zilog
, uint64_t foid
)
2946 * We should never attempt to call zil_commit on a snapshot for
2947 * a couple of reasons:
2949 * 1. A snapshot may never be modified, thus it cannot have any
2950 * in-flight itxs that would have modified the dataset.
2952 * 2. By design, when zil_commit() is called, a commit itx will
2953 * be assigned to this zilog; as a result, the zilog will be
2954 * dirtied. We must not dirty the zilog of a snapshot; there's
2955 * checks in the code that enforce this invariant, and will
2956 * cause a panic if it's not upheld.
2958 ASSERT3B(dmu_objset_is_snapshot(zilog
->zl_os
), ==, B_FALSE
);
2960 if (zilog
->zl_sync
== ZFS_SYNC_DISABLED
)
2963 if (!spa_writeable(zilog
->zl_spa
)) {
2965 * If the SPA is not writable, there should never be any
2966 * pending itxs waiting to be committed to disk. If that
2967 * weren't true, we'd skip writing those itxs out, and
2968 * would break the semantics of zil_commit(); thus, we're
2969 * verifying that truth before we return to the caller.
2971 ASSERT(list_is_empty(&zilog
->zl_lwb_list
));
2972 ASSERT3P(zilog
->zl_last_lwb_opened
, ==, NULL
);
2973 for (int i
= 0; i
< TXG_SIZE
; i
++)
2974 ASSERT3P(zilog
->zl_itxg
[i
].itxg_itxs
, ==, NULL
);
2979 * If the ZIL is suspended, we don't want to dirty it by calling
2980 * zil_commit_itx_assign() below, nor can we write out
2981 * lwbs like would be done in zil_commit_write(). Thus, we
2982 * simply rely on txg_wait_synced() to maintain the necessary
2983 * semantics, and avoid calling those functions altogether.
2985 if (zilog
->zl_suspend
> 0) {
2986 txg_wait_synced(zilog
->zl_dmu_pool
, 0);
2990 zil_commit_impl(zilog
, foid
);
2994 zil_commit_impl(zilog_t
*zilog
, uint64_t foid
)
2996 ZIL_STAT_BUMP(zil_commit_count
);
2999 * Move the "async" itxs for the specified foid to the "sync"
3000 * queues, such that they will be later committed (or skipped)
3001 * to an lwb when zil_process_commit_list() is called.
3003 * Since these "async" itxs must be committed prior to this
3004 * call to zil_commit returning, we must perform this operation
3005 * before we call zil_commit_itx_assign().
3007 zil_async_to_sync(zilog
, foid
);
3010 * We allocate a new "waiter" structure which will initially be
3011 * linked to the commit itx using the itx's "itx_private" field.
3012 * Since the commit itx doesn't represent any on-disk state,
3013 * when it's committed to an lwb, rather than copying the its
3014 * lr_t into the lwb's buffer, the commit itx's "waiter" will be
3015 * added to the lwb's list of waiters. Then, when the lwb is
3016 * committed to stable storage, each waiter in the lwb's list of
3017 * waiters will be marked "done", and signalled.
3019 * We must create the waiter and assign the commit itx prior to
3020 * calling zil_commit_writer(), or else our specific commit itx
3021 * is not guaranteed to be committed to an lwb prior to calling
3022 * zil_commit_waiter().
3024 zil_commit_waiter_t
*zcw
= zil_alloc_commit_waiter();
3025 zil_commit_itx_assign(zilog
, zcw
);
3027 zil_commit_writer(zilog
, zcw
);
3028 zil_commit_waiter(zilog
, zcw
);
3030 if (zcw
->zcw_zio_error
!= 0) {
3032 * If there was an error writing out the ZIL blocks that
3033 * this thread is waiting on, then we fallback to
3034 * relying on spa_sync() to write out the data this
3035 * thread is waiting on. Obviously this has performance
3036 * implications, but the expectation is for this to be
3037 * an exceptional case, and shouldn't occur often.
3039 DTRACE_PROBE2(zil__commit__io__error
,
3040 zilog_t
*, zilog
, zil_commit_waiter_t
*, zcw
);
3041 txg_wait_synced(zilog
->zl_dmu_pool
, 0);
3044 zil_free_commit_waiter(zcw
);
3048 * Called in syncing context to free committed log blocks and update log header.
3051 zil_sync(zilog_t
*zilog
, dmu_tx_t
*tx
)
3053 zil_header_t
*zh
= zil_header_in_syncing_context(zilog
);
3054 uint64_t txg
= dmu_tx_get_txg(tx
);
3055 spa_t
*spa
= zilog
->zl_spa
;
3056 uint64_t *replayed_seq
= &zilog
->zl_replayed_seq
[txg
& TXG_MASK
];
3060 * We don't zero out zl_destroy_txg, so make sure we don't try
3061 * to destroy it twice.
3063 if (spa_sync_pass(spa
) != 1)
3066 mutex_enter(&zilog
->zl_lock
);
3068 ASSERT(zilog
->zl_stop_sync
== 0);
3070 if (*replayed_seq
!= 0) {
3071 ASSERT(zh
->zh_replay_seq
< *replayed_seq
);
3072 zh
->zh_replay_seq
= *replayed_seq
;
3076 if (zilog
->zl_destroy_txg
== txg
) {
3077 blkptr_t blk
= zh
->zh_log
;
3079 ASSERT(list_head(&zilog
->zl_lwb_list
) == NULL
);
3081 bzero(zh
, sizeof (zil_header_t
));
3082 bzero(zilog
->zl_replayed_seq
, sizeof (zilog
->zl_replayed_seq
));
3084 if (zilog
->zl_keep_first
) {
3086 * If this block was part of log chain that couldn't
3087 * be claimed because a device was missing during
3088 * zil_claim(), but that device later returns,
3089 * then this block could erroneously appear valid.
3090 * To guard against this, assign a new GUID to the new
3091 * log chain so it doesn't matter what blk points to.
3093 zil_init_log_chain(zilog
, &blk
);
3098 while ((lwb
= list_head(&zilog
->zl_lwb_list
)) != NULL
) {
3099 zh
->zh_log
= lwb
->lwb_blk
;
3100 if (lwb
->lwb_buf
!= NULL
|| lwb
->lwb_max_txg
> txg
)
3102 list_remove(&zilog
->zl_lwb_list
, lwb
);
3103 zio_free(spa
, txg
, &lwb
->lwb_blk
);
3104 zil_free_lwb(zilog
, lwb
);
3107 * If we don't have anything left in the lwb list then
3108 * we've had an allocation failure and we need to zero
3109 * out the zil_header blkptr so that we don't end
3110 * up freeing the same block twice.
3112 if (list_head(&zilog
->zl_lwb_list
) == NULL
)
3113 BP_ZERO(&zh
->zh_log
);
3117 * Remove fastwrite on any blocks that have been pre-allocated for
3118 * the next commit. This prevents fastwrite counter pollution by
3119 * unused, long-lived LWBs.
3121 for (; lwb
!= NULL
; lwb
= list_next(&zilog
->zl_lwb_list
, lwb
)) {
3122 if (lwb
->lwb_fastwrite
&& !lwb
->lwb_write_zio
) {
3123 metaslab_fastwrite_unmark(zilog
->zl_spa
, &lwb
->lwb_blk
);
3124 lwb
->lwb_fastwrite
= 0;
3128 mutex_exit(&zilog
->zl_lock
);
3132 zil_lwb_cons(void *vbuf
, void *unused
, int kmflag
)
3134 (void) unused
, (void) kmflag
;
3136 list_create(&lwb
->lwb_itxs
, sizeof (itx_t
), offsetof(itx_t
, itx_node
));
3137 list_create(&lwb
->lwb_waiters
, sizeof (zil_commit_waiter_t
),
3138 offsetof(zil_commit_waiter_t
, zcw_node
));
3139 avl_create(&lwb
->lwb_vdev_tree
, zil_lwb_vdev_compare
,
3140 sizeof (zil_vdev_node_t
), offsetof(zil_vdev_node_t
, zv_node
));
3141 mutex_init(&lwb
->lwb_vdev_lock
, NULL
, MUTEX_DEFAULT
, NULL
);
3146 zil_lwb_dest(void *vbuf
, void *unused
)
3150 mutex_destroy(&lwb
->lwb_vdev_lock
);
3151 avl_destroy(&lwb
->lwb_vdev_tree
);
3152 list_destroy(&lwb
->lwb_waiters
);
3153 list_destroy(&lwb
->lwb_itxs
);
3159 zil_lwb_cache
= kmem_cache_create("zil_lwb_cache",
3160 sizeof (lwb_t
), 0, zil_lwb_cons
, zil_lwb_dest
, NULL
, NULL
, NULL
, 0);
3162 zil_zcw_cache
= kmem_cache_create("zil_zcw_cache",
3163 sizeof (zil_commit_waiter_t
), 0, NULL
, NULL
, NULL
, NULL
, NULL
, 0);
3165 zil_ksp
= kstat_create("zfs", 0, "zil", "misc",
3166 KSTAT_TYPE_NAMED
, sizeof (zil_stats
) / sizeof (kstat_named_t
),
3167 KSTAT_FLAG_VIRTUAL
);
3169 if (zil_ksp
!= NULL
) {
3170 zil_ksp
->ks_data
= &zil_stats
;
3171 kstat_install(zil_ksp
);
3178 kmem_cache_destroy(zil_zcw_cache
);
3179 kmem_cache_destroy(zil_lwb_cache
);
3181 if (zil_ksp
!= NULL
) {
3182 kstat_delete(zil_ksp
);
3188 zil_set_sync(zilog_t
*zilog
, uint64_t sync
)
3190 zilog
->zl_sync
= sync
;
3194 zil_set_logbias(zilog_t
*zilog
, uint64_t logbias
)
3196 zilog
->zl_logbias
= logbias
;
3200 zil_alloc(objset_t
*os
, zil_header_t
*zh_phys
)
3204 zilog
= kmem_zalloc(sizeof (zilog_t
), KM_SLEEP
);
3206 zilog
->zl_header
= zh_phys
;
3208 zilog
->zl_spa
= dmu_objset_spa(os
);
3209 zilog
->zl_dmu_pool
= dmu_objset_pool(os
);
3210 zilog
->zl_destroy_txg
= TXG_INITIAL
- 1;
3211 zilog
->zl_logbias
= dmu_objset_logbias(os
);
3212 zilog
->zl_sync
= dmu_objset_syncprop(os
);
3213 zilog
->zl_dirty_max_txg
= 0;
3214 zilog
->zl_last_lwb_opened
= NULL
;
3215 zilog
->zl_last_lwb_latency
= 0;
3216 zilog
->zl_max_block_size
= zil_maxblocksize
;
3218 mutex_init(&zilog
->zl_lock
, NULL
, MUTEX_DEFAULT
, NULL
);
3219 mutex_init(&zilog
->zl_issuer_lock
, NULL
, MUTEX_DEFAULT
, NULL
);
3221 for (int i
= 0; i
< TXG_SIZE
; i
++) {
3222 mutex_init(&zilog
->zl_itxg
[i
].itxg_lock
, NULL
,
3223 MUTEX_DEFAULT
, NULL
);
3226 list_create(&zilog
->zl_lwb_list
, sizeof (lwb_t
),
3227 offsetof(lwb_t
, lwb_node
));
3229 list_create(&zilog
->zl_itx_commit_list
, sizeof (itx_t
),
3230 offsetof(itx_t
, itx_node
));
3232 cv_init(&zilog
->zl_cv_suspend
, NULL
, CV_DEFAULT
, NULL
);
3238 zil_free(zilog_t
*zilog
)
3242 zilog
->zl_stop_sync
= 1;
3244 ASSERT0(zilog
->zl_suspend
);
3245 ASSERT0(zilog
->zl_suspending
);
3247 ASSERT(list_is_empty(&zilog
->zl_lwb_list
));
3248 list_destroy(&zilog
->zl_lwb_list
);
3250 ASSERT(list_is_empty(&zilog
->zl_itx_commit_list
));
3251 list_destroy(&zilog
->zl_itx_commit_list
);
3253 for (i
= 0; i
< TXG_SIZE
; i
++) {
3255 * It's possible for an itx to be generated that doesn't dirty
3256 * a txg (e.g. ztest TX_TRUNCATE). So there's no zil_clean()
3257 * callback to remove the entry. We remove those here.
3259 * Also free up the ziltest itxs.
3261 if (zilog
->zl_itxg
[i
].itxg_itxs
)
3262 zil_itxg_clean(zilog
->zl_itxg
[i
].itxg_itxs
);
3263 mutex_destroy(&zilog
->zl_itxg
[i
].itxg_lock
);
3266 mutex_destroy(&zilog
->zl_issuer_lock
);
3267 mutex_destroy(&zilog
->zl_lock
);
3269 cv_destroy(&zilog
->zl_cv_suspend
);
3271 kmem_free(zilog
, sizeof (zilog_t
));
3275 * Open an intent log.
3278 zil_open(objset_t
*os
, zil_get_data_t
*get_data
)
3280 zilog_t
*zilog
= dmu_objset_zil(os
);
3282 ASSERT3P(zilog
->zl_get_data
, ==, NULL
);
3283 ASSERT3P(zilog
->zl_last_lwb_opened
, ==, NULL
);
3284 ASSERT(list_is_empty(&zilog
->zl_lwb_list
));
3286 zilog
->zl_get_data
= get_data
;
3292 * Close an intent log.
3295 zil_close(zilog_t
*zilog
)
3300 if (!dmu_objset_is_snapshot(zilog
->zl_os
)) {
3301 zil_commit(zilog
, 0);
3303 ASSERT3P(list_tail(&zilog
->zl_lwb_list
), ==, NULL
);
3304 ASSERT0(zilog
->zl_dirty_max_txg
);
3305 ASSERT3B(zilog_is_dirty(zilog
), ==, B_FALSE
);
3308 mutex_enter(&zilog
->zl_lock
);
3309 lwb
= list_tail(&zilog
->zl_lwb_list
);
3311 txg
= zilog
->zl_dirty_max_txg
;
3313 txg
= MAX(zilog
->zl_dirty_max_txg
, lwb
->lwb_max_txg
);
3314 mutex_exit(&zilog
->zl_lock
);
3317 * We need to use txg_wait_synced() to wait long enough for the
3318 * ZIL to be clean, and to wait for all pending lwbs to be
3322 txg_wait_synced(zilog
->zl_dmu_pool
, txg
);
3324 if (zilog_is_dirty(zilog
))
3325 zfs_dbgmsg("zil (%px) is dirty, txg %llu", zilog
,
3327 if (txg
< spa_freeze_txg(zilog
->zl_spa
))
3328 VERIFY(!zilog_is_dirty(zilog
));
3330 zilog
->zl_get_data
= NULL
;
3333 * We should have only one lwb left on the list; remove it now.
3335 mutex_enter(&zilog
->zl_lock
);
3336 lwb
= list_head(&zilog
->zl_lwb_list
);
3338 ASSERT3P(lwb
, ==, list_tail(&zilog
->zl_lwb_list
));
3339 ASSERT3S(lwb
->lwb_state
, !=, LWB_STATE_ISSUED
);
3341 if (lwb
->lwb_fastwrite
)
3342 metaslab_fastwrite_unmark(zilog
->zl_spa
, &lwb
->lwb_blk
);
3344 list_remove(&zilog
->zl_lwb_list
, lwb
);
3345 zio_buf_free(lwb
->lwb_buf
, lwb
->lwb_sz
);
3346 zil_free_lwb(zilog
, lwb
);
3348 mutex_exit(&zilog
->zl_lock
);
3351 static char *suspend_tag
= "zil suspending";
3354 * Suspend an intent log. While in suspended mode, we still honor
3355 * synchronous semantics, but we rely on txg_wait_synced() to do it.
3356 * On old version pools, we suspend the log briefly when taking a
3357 * snapshot so that it will have an empty intent log.
3359 * Long holds are not really intended to be used the way we do here --
3360 * held for such a short time. A concurrent caller of dsl_dataset_long_held()
3361 * could fail. Therefore we take pains to only put a long hold if it is
3362 * actually necessary. Fortunately, it will only be necessary if the
3363 * objset is currently mounted (or the ZVOL equivalent). In that case it
3364 * will already have a long hold, so we are not really making things any worse.
3366 * Ideally, we would locate the existing long-holder (i.e. the zfsvfs_t or
3367 * zvol_state_t), and use their mechanism to prevent their hold from being
3368 * dropped (e.g. VFS_HOLD()). However, that would be even more pain for
3371 * if cookiep == NULL, this does both the suspend & resume.
3372 * Otherwise, it returns with the dataset "long held", and the cookie
3373 * should be passed into zil_resume().
3376 zil_suspend(const char *osname
, void **cookiep
)
3380 const zil_header_t
*zh
;
3383 error
= dmu_objset_hold(osname
, suspend_tag
, &os
);
3386 zilog
= dmu_objset_zil(os
);
3388 mutex_enter(&zilog
->zl_lock
);
3389 zh
= zilog
->zl_header
;
3391 if (zh
->zh_flags
& ZIL_REPLAY_NEEDED
) { /* unplayed log */
3392 mutex_exit(&zilog
->zl_lock
);
3393 dmu_objset_rele(os
, suspend_tag
);
3394 return (SET_ERROR(EBUSY
));
3398 * Don't put a long hold in the cases where we can avoid it. This
3399 * is when there is no cookie so we are doing a suspend & resume
3400 * (i.e. called from zil_vdev_offline()), and there's nothing to do
3401 * for the suspend because it's already suspended, or there's no ZIL.
3403 if (cookiep
== NULL
&& !zilog
->zl_suspending
&&
3404 (zilog
->zl_suspend
> 0 || BP_IS_HOLE(&zh
->zh_log
))) {
3405 mutex_exit(&zilog
->zl_lock
);
3406 dmu_objset_rele(os
, suspend_tag
);
3410 dsl_dataset_long_hold(dmu_objset_ds(os
), suspend_tag
);
3411 dsl_pool_rele(dmu_objset_pool(os
), suspend_tag
);
3413 zilog
->zl_suspend
++;
3415 if (zilog
->zl_suspend
> 1) {
3417 * Someone else is already suspending it.
3418 * Just wait for them to finish.
3421 while (zilog
->zl_suspending
)
3422 cv_wait(&zilog
->zl_cv_suspend
, &zilog
->zl_lock
);
3423 mutex_exit(&zilog
->zl_lock
);
3425 if (cookiep
== NULL
)
3433 * If there is no pointer to an on-disk block, this ZIL must not
3434 * be active (e.g. filesystem not mounted), so there's nothing
3437 if (BP_IS_HOLE(&zh
->zh_log
)) {
3438 ASSERT(cookiep
!= NULL
); /* fast path already handled */
3441 mutex_exit(&zilog
->zl_lock
);
3446 * The ZIL has work to do. Ensure that the associated encryption
3447 * key will remain mapped while we are committing the log by
3448 * grabbing a reference to it. If the key isn't loaded we have no
3449 * choice but to return an error until the wrapping key is loaded.
3451 if (os
->os_encrypted
&&
3452 dsl_dataset_create_key_mapping(dmu_objset_ds(os
)) != 0) {
3453 zilog
->zl_suspend
--;
3454 mutex_exit(&zilog
->zl_lock
);
3455 dsl_dataset_long_rele(dmu_objset_ds(os
), suspend_tag
);
3456 dsl_dataset_rele(dmu_objset_ds(os
), suspend_tag
);
3457 return (SET_ERROR(EACCES
));
3460 zilog
->zl_suspending
= B_TRUE
;
3461 mutex_exit(&zilog
->zl_lock
);
3464 * We need to use zil_commit_impl to ensure we wait for all
3465 * LWB_STATE_OPENED and LWB_STATE_ISSUED lwbs to be committed
3466 * to disk before proceeding. If we used zil_commit instead, it
3467 * would just call txg_wait_synced(), because zl_suspend is set.
3468 * txg_wait_synced() doesn't wait for these lwb's to be
3469 * LWB_STATE_FLUSH_DONE before returning.
3471 zil_commit_impl(zilog
, 0);
3474 * Now that we've ensured all lwb's are LWB_STATE_FLUSH_DONE, we
3475 * use txg_wait_synced() to ensure the data from the zilog has
3476 * migrated to the main pool before calling zil_destroy().
3478 txg_wait_synced(zilog
->zl_dmu_pool
, 0);
3480 zil_destroy(zilog
, B_FALSE
);
3482 mutex_enter(&zilog
->zl_lock
);
3483 zilog
->zl_suspending
= B_FALSE
;
3484 cv_broadcast(&zilog
->zl_cv_suspend
);
3485 mutex_exit(&zilog
->zl_lock
);
3487 if (os
->os_encrypted
)
3488 dsl_dataset_remove_key_mapping(dmu_objset_ds(os
));
3490 if (cookiep
== NULL
)
3498 zil_resume(void *cookie
)
3500 objset_t
*os
= cookie
;
3501 zilog_t
*zilog
= dmu_objset_zil(os
);
3503 mutex_enter(&zilog
->zl_lock
);
3504 ASSERT(zilog
->zl_suspend
!= 0);
3505 zilog
->zl_suspend
--;
3506 mutex_exit(&zilog
->zl_lock
);
3507 dsl_dataset_long_rele(dmu_objset_ds(os
), suspend_tag
);
3508 dsl_dataset_rele(dmu_objset_ds(os
), suspend_tag
);
3511 typedef struct zil_replay_arg
{
3512 zil_replay_func_t
*const *zr_replay
;
3514 boolean_t zr_byteswap
;
3519 zil_replay_error(zilog_t
*zilog
, const lr_t
*lr
, int error
)
3521 char name
[ZFS_MAX_DATASET_NAME_LEN
];
3523 zilog
->zl_replaying_seq
--; /* didn't actually replay this one */
3525 dmu_objset_name(zilog
->zl_os
, name
);
3527 cmn_err(CE_WARN
, "ZFS replay transaction error %d, "
3528 "dataset %s, seq 0x%llx, txtype %llu %s\n", error
, name
,
3529 (u_longlong_t
)lr
->lrc_seq
,
3530 (u_longlong_t
)(lr
->lrc_txtype
& ~TX_CI
),
3531 (lr
->lrc_txtype
& TX_CI
) ? "CI" : "");
3537 zil_replay_log_record(zilog_t
*zilog
, const lr_t
*lr
, void *zra
,
3540 zil_replay_arg_t
*zr
= zra
;
3541 const zil_header_t
*zh
= zilog
->zl_header
;
3542 uint64_t reclen
= lr
->lrc_reclen
;
3543 uint64_t txtype
= lr
->lrc_txtype
;
3546 zilog
->zl_replaying_seq
= lr
->lrc_seq
;
3548 if (lr
->lrc_seq
<= zh
->zh_replay_seq
) /* already replayed */
3551 if (lr
->lrc_txg
< claim_txg
) /* already committed */
3554 /* Strip case-insensitive bit, still present in log record */
3557 if (txtype
== 0 || txtype
>= TX_MAX_TYPE
)
3558 return (zil_replay_error(zilog
, lr
, EINVAL
));
3561 * If this record type can be logged out of order, the object
3562 * (lr_foid) may no longer exist. That's legitimate, not an error.
3564 if (TX_OOO(txtype
)) {
3565 error
= dmu_object_info(zilog
->zl_os
,
3566 LR_FOID_GET_OBJ(((lr_ooo_t
*)lr
)->lr_foid
), NULL
);
3567 if (error
== ENOENT
|| error
== EEXIST
)
3572 * Make a copy of the data so we can revise and extend it.
3574 bcopy(lr
, zr
->zr_lr
, reclen
);
3577 * If this is a TX_WRITE with a blkptr, suck in the data.
3579 if (txtype
== TX_WRITE
&& reclen
== sizeof (lr_write_t
)) {
3580 error
= zil_read_log_data(zilog
, (lr_write_t
*)lr
,
3581 zr
->zr_lr
+ reclen
);
3583 return (zil_replay_error(zilog
, lr
, error
));
3587 * The log block containing this lr may have been byteswapped
3588 * so that we can easily examine common fields like lrc_txtype.
3589 * However, the log is a mix of different record types, and only the
3590 * replay vectors know how to byteswap their records. Therefore, if
3591 * the lr was byteswapped, undo it before invoking the replay vector.
3593 if (zr
->zr_byteswap
)
3594 byteswap_uint64_array(zr
->zr_lr
, reclen
);
3597 * We must now do two things atomically: replay this log record,
3598 * and update the log header sequence number to reflect the fact that
3599 * we did so. At the end of each replay function the sequence number
3600 * is updated if we are in replay mode.
3602 error
= zr
->zr_replay
[txtype
](zr
->zr_arg
, zr
->zr_lr
, zr
->zr_byteswap
);
3605 * The DMU's dnode layer doesn't see removes until the txg
3606 * commits, so a subsequent claim can spuriously fail with
3607 * EEXIST. So if we receive any error we try syncing out
3608 * any removes then retry the transaction. Note that we
3609 * specify B_FALSE for byteswap now, so we don't do it twice.
3611 txg_wait_synced(spa_get_dsl(zilog
->zl_spa
), 0);
3612 error
= zr
->zr_replay
[txtype
](zr
->zr_arg
, zr
->zr_lr
, B_FALSE
);
3614 return (zil_replay_error(zilog
, lr
, error
));
3620 zil_incr_blks(zilog_t
*zilog
, const blkptr_t
*bp
, void *arg
, uint64_t claim_txg
)
3622 (void) bp
, (void) arg
, (void) claim_txg
;
3624 zilog
->zl_replay_blks
++;
3630 * If this dataset has a non-empty intent log, replay it and destroy it.
3633 zil_replay(objset_t
*os
, void *arg
,
3634 zil_replay_func_t
*const replay_func
[TX_MAX_TYPE
])
3636 zilog_t
*zilog
= dmu_objset_zil(os
);
3637 const zil_header_t
*zh
= zilog
->zl_header
;
3638 zil_replay_arg_t zr
;
3640 if ((zh
->zh_flags
& ZIL_REPLAY_NEEDED
) == 0) {
3641 zil_destroy(zilog
, B_TRUE
);
3645 zr
.zr_replay
= replay_func
;
3647 zr
.zr_byteswap
= BP_SHOULD_BYTESWAP(&zh
->zh_log
);
3648 zr
.zr_lr
= vmem_alloc(2 * SPA_MAXBLOCKSIZE
, KM_SLEEP
);
3651 * Wait for in-progress removes to sync before starting replay.
3653 txg_wait_synced(zilog
->zl_dmu_pool
, 0);
3655 zilog
->zl_replay
= B_TRUE
;
3656 zilog
->zl_replay_time
= ddi_get_lbolt();
3657 ASSERT(zilog
->zl_replay_blks
== 0);
3658 (void) zil_parse(zilog
, zil_incr_blks
, zil_replay_log_record
, &zr
,
3659 zh
->zh_claim_txg
, B_TRUE
);
3660 vmem_free(zr
.zr_lr
, 2 * SPA_MAXBLOCKSIZE
);
3662 zil_destroy(zilog
, B_FALSE
);
3663 txg_wait_synced(zilog
->zl_dmu_pool
, zilog
->zl_destroy_txg
);
3664 zilog
->zl_replay
= B_FALSE
;
3668 zil_replaying(zilog_t
*zilog
, dmu_tx_t
*tx
)
3670 if (zilog
->zl_sync
== ZFS_SYNC_DISABLED
)
3673 if (zilog
->zl_replay
) {
3674 dsl_dataset_dirty(dmu_objset_ds(zilog
->zl_os
), tx
);
3675 zilog
->zl_replayed_seq
[dmu_tx_get_txg(tx
) & TXG_MASK
] =
3676 zilog
->zl_replaying_seq
;
3684 zil_reset(const char *osname
, void *arg
)
3688 int error
= zil_suspend(osname
, NULL
);
3689 /* EACCES means crypto key not loaded */
3690 if ((error
== EACCES
) || (error
== EBUSY
))
3691 return (SET_ERROR(error
));
3693 return (SET_ERROR(EEXIST
));
3697 EXPORT_SYMBOL(zil_alloc
);
3698 EXPORT_SYMBOL(zil_free
);
3699 EXPORT_SYMBOL(zil_open
);
3700 EXPORT_SYMBOL(zil_close
);
3701 EXPORT_SYMBOL(zil_replay
);
3702 EXPORT_SYMBOL(zil_replaying
);
3703 EXPORT_SYMBOL(zil_destroy
);
3704 EXPORT_SYMBOL(zil_destroy_sync
);
3705 EXPORT_SYMBOL(zil_itx_create
);
3706 EXPORT_SYMBOL(zil_itx_destroy
);
3707 EXPORT_SYMBOL(zil_itx_assign
);
3708 EXPORT_SYMBOL(zil_commit
);
3709 EXPORT_SYMBOL(zil_claim
);
3710 EXPORT_SYMBOL(zil_check_log_chain
);
3711 EXPORT_SYMBOL(zil_sync
);
3712 EXPORT_SYMBOL(zil_clean
);
3713 EXPORT_SYMBOL(zil_suspend
);
3714 EXPORT_SYMBOL(zil_resume
);
3715 EXPORT_SYMBOL(zil_lwb_add_block
);
3716 EXPORT_SYMBOL(zil_bp_tree_add
);
3717 EXPORT_SYMBOL(zil_set_sync
);
3718 EXPORT_SYMBOL(zil_set_logbias
);
3721 ZFS_MODULE_PARAM(zfs
, zfs_
, commit_timeout_pct
, INT
, ZMOD_RW
,
3722 "ZIL block open timeout percentage");
3724 ZFS_MODULE_PARAM(zfs_zil
, zil_
, replay_disable
, INT
, ZMOD_RW
,
3725 "Disable intent logging replay");
3727 ZFS_MODULE_PARAM(zfs_zil
, zil_
, nocacheflush
, INT
, ZMOD_RW
,
3728 "Disable ZIL cache flushes");
3730 ZFS_MODULE_PARAM(zfs_zil
, zil_
, slog_bulk
, ULONG
, ZMOD_RW
,
3731 "Limit in bytes slog sync writes per commit");
3733 ZFS_MODULE_PARAM(zfs_zil
, zil_
, maxblocksize
, INT
, ZMOD_RW
,
3734 "Limit in bytes of ZIL log block size");