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_zil.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 fileystem, 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 int zfs_commit_timeout_pct
= 5;
95 * See zil.h for more information about these fields.
97 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 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 unsigned long zil_slog_bulk
= 768 * 1024;
135 static kmem_cache_t
*zil_lwb_cache
;
136 static kmem_cache_t
*zil_zcw_cache
;
138 static void zil_async_to_sync(zilog_t
*zilog
, uint64_t foid
);
140 #define LWB_EMPTY(lwb) ((BP_GET_LSIZE(&lwb->lwb_blk) - \
141 sizeof (zil_chain_t)) == (lwb->lwb_sz - lwb->lwb_nused))
144 zil_bp_compare(const void *x1
, const void *x2
)
146 const dva_t
*dva1
= &((zil_bp_node_t
*)x1
)->zn_dva
;
147 const dva_t
*dva2
= &((zil_bp_node_t
*)x2
)->zn_dva
;
149 int cmp
= AVL_CMP(DVA_GET_VDEV(dva1
), DVA_GET_VDEV(dva2
));
153 return (AVL_CMP(DVA_GET_OFFSET(dva1
), DVA_GET_OFFSET(dva2
)));
157 zil_bp_tree_init(zilog_t
*zilog
)
159 avl_create(&zilog
->zl_bp_tree
, zil_bp_compare
,
160 sizeof (zil_bp_node_t
), offsetof(zil_bp_node_t
, zn_node
));
164 zil_bp_tree_fini(zilog_t
*zilog
)
166 avl_tree_t
*t
= &zilog
->zl_bp_tree
;
170 while ((zn
= avl_destroy_nodes(t
, &cookie
)) != NULL
)
171 kmem_free(zn
, sizeof (zil_bp_node_t
));
177 zil_bp_tree_add(zilog_t
*zilog
, const blkptr_t
*bp
)
179 avl_tree_t
*t
= &zilog
->zl_bp_tree
;
184 if (BP_IS_EMBEDDED(bp
))
187 dva
= BP_IDENTITY(bp
);
189 if (avl_find(t
, dva
, &where
) != NULL
)
190 return (SET_ERROR(EEXIST
));
192 zn
= kmem_alloc(sizeof (zil_bp_node_t
), KM_SLEEP
);
194 avl_insert(t
, zn
, where
);
199 static zil_header_t
*
200 zil_header_in_syncing_context(zilog_t
*zilog
)
202 return ((zil_header_t
*)zilog
->zl_header
);
206 zil_init_log_chain(zilog_t
*zilog
, blkptr_t
*bp
)
208 zio_cksum_t
*zc
= &bp
->blk_cksum
;
210 zc
->zc_word
[ZIL_ZC_GUID_0
] = spa_get_random(-1ULL);
211 zc
->zc_word
[ZIL_ZC_GUID_1
] = spa_get_random(-1ULL);
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
);
437 zil_clear_log_block(zilog_t
*zilog
, blkptr_t
*bp
, void *tx
, uint64_t first_txg
)
439 ASSERT(!BP_IS_HOLE(bp
));
442 * As we call this function from the context of a rewind to a
443 * checkpoint, each ZIL block whose txg is later than the txg
444 * that we rewind to is invalid. Thus, we return -1 so
445 * zil_parse() doesn't attempt to read it.
447 if (bp
->blk_birth
>= first_txg
)
450 if (zil_bp_tree_add(zilog
, bp
) != 0)
453 zio_free(zilog
->zl_spa
, first_txg
, bp
);
459 zil_noop_log_record(zilog_t
*zilog
, lr_t
*lrc
, void *tx
, uint64_t first_txg
)
465 zil_claim_log_block(zilog_t
*zilog
, blkptr_t
*bp
, void *tx
, uint64_t first_txg
)
468 * Claim log block if not already committed and not already claimed.
469 * If tx == NULL, just verify that the block is claimable.
471 if (BP_IS_HOLE(bp
) || bp
->blk_birth
< first_txg
||
472 zil_bp_tree_add(zilog
, bp
) != 0)
475 return (zio_wait(zio_claim(NULL
, zilog
->zl_spa
,
476 tx
== NULL
? 0 : first_txg
, bp
, spa_claim_notify
, NULL
,
477 ZIO_FLAG_CANFAIL
| ZIO_FLAG_SPECULATIVE
| ZIO_FLAG_SCRUB
)));
481 zil_claim_log_record(zilog_t
*zilog
, lr_t
*lrc
, void *tx
, uint64_t first_txg
)
483 lr_write_t
*lr
= (lr_write_t
*)lrc
;
486 if (lrc
->lrc_txtype
!= TX_WRITE
)
490 * If the block is not readable, don't claim it. This can happen
491 * in normal operation when a log block is written to disk before
492 * some of the dmu_sync() blocks it points to. In this case, the
493 * transaction cannot have been committed to anyone (we would have
494 * waited for all writes to be stable first), so it is semantically
495 * correct to declare this the end of the log.
497 if (lr
->lr_blkptr
.blk_birth
>= first_txg
) {
498 error
= zil_read_log_data(zilog
, lr
, NULL
);
503 return (zil_claim_log_block(zilog
, &lr
->lr_blkptr
, tx
, first_txg
));
508 zil_free_log_block(zilog_t
*zilog
, blkptr_t
*bp
, void *tx
, uint64_t claim_txg
)
510 zio_free(zilog
->zl_spa
, dmu_tx_get_txg(tx
), bp
);
516 zil_free_log_record(zilog_t
*zilog
, lr_t
*lrc
, void *tx
, uint64_t claim_txg
)
518 lr_write_t
*lr
= (lr_write_t
*)lrc
;
519 blkptr_t
*bp
= &lr
->lr_blkptr
;
522 * If we previously claimed it, we need to free it.
524 if (claim_txg
!= 0 && lrc
->lrc_txtype
== TX_WRITE
&&
525 bp
->blk_birth
>= claim_txg
&& zil_bp_tree_add(zilog
, bp
) == 0 &&
527 zio_free(zilog
->zl_spa
, dmu_tx_get_txg(tx
), bp
);
533 zil_lwb_vdev_compare(const void *x1
, const void *x2
)
535 const uint64_t v1
= ((zil_vdev_node_t
*)x1
)->zv_vdev
;
536 const uint64_t v2
= ((zil_vdev_node_t
*)x2
)->zv_vdev
;
538 return (AVL_CMP(v1
, v2
));
542 zil_alloc_lwb(zilog_t
*zilog
, blkptr_t
*bp
, boolean_t slog
, uint64_t txg
,
547 lwb
= kmem_cache_alloc(zil_lwb_cache
, KM_SLEEP
);
548 lwb
->lwb_zilog
= zilog
;
550 lwb
->lwb_fastwrite
= fastwrite
;
551 lwb
->lwb_slog
= slog
;
552 lwb
->lwb_state
= LWB_STATE_CLOSED
;
553 lwb
->lwb_buf
= zio_buf_alloc(BP_GET_LSIZE(bp
));
554 lwb
->lwb_max_txg
= txg
;
555 lwb
->lwb_write_zio
= NULL
;
556 lwb
->lwb_root_zio
= NULL
;
558 lwb
->lwb_issued_timestamp
= 0;
559 if (BP_GET_CHECKSUM(bp
) == ZIO_CHECKSUM_ZILOG2
) {
560 lwb
->lwb_nused
= sizeof (zil_chain_t
);
561 lwb
->lwb_sz
= BP_GET_LSIZE(bp
);
564 lwb
->lwb_sz
= BP_GET_LSIZE(bp
) - sizeof (zil_chain_t
);
567 mutex_enter(&zilog
->zl_lock
);
568 list_insert_tail(&zilog
->zl_lwb_list
, lwb
);
569 mutex_exit(&zilog
->zl_lock
);
571 ASSERT(!MUTEX_HELD(&lwb
->lwb_vdev_lock
));
572 ASSERT(avl_is_empty(&lwb
->lwb_vdev_tree
));
573 VERIFY(list_is_empty(&lwb
->lwb_waiters
));
574 VERIFY(list_is_empty(&lwb
->lwb_itxs
));
580 zil_free_lwb(zilog_t
*zilog
, lwb_t
*lwb
)
582 ASSERT(MUTEX_HELD(&zilog
->zl_lock
));
583 ASSERT(!MUTEX_HELD(&lwb
->lwb_vdev_lock
));
584 VERIFY(list_is_empty(&lwb
->lwb_waiters
));
585 VERIFY(list_is_empty(&lwb
->lwb_itxs
));
586 ASSERT(avl_is_empty(&lwb
->lwb_vdev_tree
));
587 ASSERT3P(lwb
->lwb_write_zio
, ==, NULL
);
588 ASSERT3P(lwb
->lwb_root_zio
, ==, NULL
);
589 ASSERT3U(lwb
->lwb_max_txg
, <=, spa_syncing_txg(zilog
->zl_spa
));
590 ASSERT(lwb
->lwb_state
== LWB_STATE_CLOSED
||
591 lwb
->lwb_state
== LWB_STATE_FLUSH_DONE
);
594 * Clear the zilog's field to indicate this lwb is no longer
595 * valid, and prevent use-after-free errors.
597 if (zilog
->zl_last_lwb_opened
== lwb
)
598 zilog
->zl_last_lwb_opened
= NULL
;
600 kmem_cache_free(zil_lwb_cache
, lwb
);
604 * Called when we create in-memory log transactions so that we know
605 * to cleanup the itxs at the end of spa_sync().
608 zilog_dirty(zilog_t
*zilog
, uint64_t txg
)
610 dsl_pool_t
*dp
= zilog
->zl_dmu_pool
;
611 dsl_dataset_t
*ds
= dmu_objset_ds(zilog
->zl_os
);
613 ASSERT(spa_writeable(zilog
->zl_spa
));
615 if (ds
->ds_is_snapshot
)
616 panic("dirtying snapshot!");
618 if (txg_list_add(&dp
->dp_dirty_zilogs
, zilog
, txg
)) {
619 /* up the hold count until we can be written out */
620 dmu_buf_add_ref(ds
->ds_dbuf
, zilog
);
622 zilog
->zl_dirty_max_txg
= MAX(txg
, zilog
->zl_dirty_max_txg
);
627 * Determine if the zil is dirty in the specified txg. Callers wanting to
628 * ensure that the dirty state does not change must hold the itxg_lock for
629 * the specified txg. Holding the lock will ensure that the zil cannot be
630 * dirtied (zil_itx_assign) or cleaned (zil_clean) while we check its current
634 zilog_is_dirty_in_txg(zilog_t
*zilog
, uint64_t txg
)
636 dsl_pool_t
*dp
= zilog
->zl_dmu_pool
;
638 if (txg_list_member(&dp
->dp_dirty_zilogs
, zilog
, txg
& TXG_MASK
))
644 * Determine if the zil is dirty. The zil is considered dirty if it has
645 * any pending itx records that have not been cleaned by zil_clean().
648 zilog_is_dirty(zilog_t
*zilog
)
650 dsl_pool_t
*dp
= zilog
->zl_dmu_pool
;
652 for (int t
= 0; t
< TXG_SIZE
; t
++) {
653 if (txg_list_member(&dp
->dp_dirty_zilogs
, zilog
, t
))
660 * Create an on-disk intent log.
663 zil_create(zilog_t
*zilog
)
665 const zil_header_t
*zh
= zilog
->zl_header
;
671 boolean_t fastwrite
= FALSE
;
672 boolean_t slog
= FALSE
;
675 * Wait for any previous destroy to complete.
677 txg_wait_synced(zilog
->zl_dmu_pool
, zilog
->zl_destroy_txg
);
679 ASSERT(zh
->zh_claim_txg
== 0);
680 ASSERT(zh
->zh_replay_seq
== 0);
685 * Allocate an initial log block if:
686 * - there isn't one already
687 * - the existing block is the wrong endianness
689 if (BP_IS_HOLE(&blk
) || BP_SHOULD_BYTESWAP(&blk
)) {
690 tx
= dmu_tx_create(zilog
->zl_os
);
691 VERIFY0(dmu_tx_assign(tx
, TXG_WAIT
));
692 dsl_dataset_dirty(dmu_objset_ds(zilog
->zl_os
), tx
);
693 txg
= dmu_tx_get_txg(tx
);
695 if (!BP_IS_HOLE(&blk
)) {
696 zio_free(zilog
->zl_spa
, txg
, &blk
);
700 error
= zio_alloc_zil(zilog
->zl_spa
, zilog
->zl_os
, txg
, &blk
,
701 ZIL_MIN_BLKSZ
, &slog
);
705 zil_init_log_chain(zilog
, &blk
);
709 * Allocate a log write block (lwb) for the first log block.
712 lwb
= zil_alloc_lwb(zilog
, &blk
, slog
, txg
, fastwrite
);
715 * If we just allocated the first log block, commit our transaction
716 * and wait for zil_sync() to stuff the block pointer into zh_log.
717 * (zh is part of the MOS, so we cannot modify it in open context.)
721 txg_wait_synced(zilog
->zl_dmu_pool
, txg
);
724 ASSERT(error
!= 0 || bcmp(&blk
, &zh
->zh_log
, sizeof (blk
)) == 0);
725 IMPLY(error
== 0, lwb
!= NULL
);
731 * In one tx, free all log blocks and clear the log header. If keep_first
732 * is set, then we're replaying a log with no content. We want to keep the
733 * first block, however, so that the first synchronous transaction doesn't
734 * require a txg_wait_synced() in zil_create(). We don't need to
735 * txg_wait_synced() here either when keep_first is set, because both
736 * zil_create() and zil_destroy() will wait for any in-progress destroys
740 zil_destroy(zilog_t
*zilog
, boolean_t keep_first
)
742 const zil_header_t
*zh
= zilog
->zl_header
;
748 * Wait for any previous destroy to complete.
750 txg_wait_synced(zilog
->zl_dmu_pool
, zilog
->zl_destroy_txg
);
752 zilog
->zl_old_header
= *zh
; /* debugging aid */
754 if (BP_IS_HOLE(&zh
->zh_log
))
757 tx
= dmu_tx_create(zilog
->zl_os
);
758 VERIFY0(dmu_tx_assign(tx
, TXG_WAIT
));
759 dsl_dataset_dirty(dmu_objset_ds(zilog
->zl_os
), tx
);
760 txg
= dmu_tx_get_txg(tx
);
762 mutex_enter(&zilog
->zl_lock
);
764 ASSERT3U(zilog
->zl_destroy_txg
, <, txg
);
765 zilog
->zl_destroy_txg
= txg
;
766 zilog
->zl_keep_first
= keep_first
;
768 if (!list_is_empty(&zilog
->zl_lwb_list
)) {
769 ASSERT(zh
->zh_claim_txg
== 0);
771 while ((lwb
= list_head(&zilog
->zl_lwb_list
)) != NULL
) {
772 if (lwb
->lwb_fastwrite
)
773 metaslab_fastwrite_unmark(zilog
->zl_spa
,
776 list_remove(&zilog
->zl_lwb_list
, lwb
);
777 if (lwb
->lwb_buf
!= NULL
)
778 zio_buf_free(lwb
->lwb_buf
, lwb
->lwb_sz
);
779 zio_free(zilog
->zl_spa
, txg
, &lwb
->lwb_blk
);
780 zil_free_lwb(zilog
, lwb
);
782 } else if (!keep_first
) {
783 zil_destroy_sync(zilog
, tx
);
785 mutex_exit(&zilog
->zl_lock
);
791 zil_destroy_sync(zilog_t
*zilog
, dmu_tx_t
*tx
)
793 ASSERT(list_is_empty(&zilog
->zl_lwb_list
));
794 (void) zil_parse(zilog
, zil_free_log_block
,
795 zil_free_log_record
, tx
, zilog
->zl_header
->zh_claim_txg
, B_FALSE
);
799 zil_claim(dsl_pool_t
*dp
, dsl_dataset_t
*ds
, void *txarg
)
801 dmu_tx_t
*tx
= txarg
;
808 error
= dmu_objset_own_obj(dp
, ds
->ds_object
,
809 DMU_OST_ANY
, B_FALSE
, B_FALSE
, FTAG
, &os
);
812 * EBUSY indicates that the objset is inconsistent, in which
813 * case it can not have a ZIL.
815 if (error
!= EBUSY
) {
816 cmn_err(CE_WARN
, "can't open objset for %llu, error %u",
817 (unsigned long long)ds
->ds_object
, error
);
823 zilog
= dmu_objset_zil(os
);
824 zh
= zil_header_in_syncing_context(zilog
);
825 ASSERT3U(tx
->tx_txg
, ==, spa_first_txg(zilog
->zl_spa
));
826 first_txg
= spa_min_claim_txg(zilog
->zl_spa
);
829 * If the spa_log_state is not set to be cleared, check whether
830 * the current uberblock is a checkpoint one and if the current
831 * header has been claimed before moving on.
833 * If the current uberblock is a checkpointed uberblock then
834 * one of the following scenarios took place:
836 * 1] We are currently rewinding to the checkpoint of the pool.
837 * 2] We crashed in the middle of a checkpoint rewind but we
838 * did manage to write the checkpointed uberblock to the
839 * vdev labels, so when we tried to import the pool again
840 * the checkpointed uberblock was selected from the import
843 * In both cases we want to zero out all the ZIL blocks, except
844 * the ones that have been claimed at the time of the checkpoint
845 * (their zh_claim_txg != 0). The reason is that these blocks
846 * may be corrupted since we may have reused their locations on
847 * disk after we took the checkpoint.
849 * We could try to set spa_log_state to SPA_LOG_CLEAR earlier
850 * when we first figure out whether the current uberblock is
851 * checkpointed or not. Unfortunately, that would discard all
852 * the logs, including the ones that are claimed, and we would
855 if (spa_get_log_state(zilog
->zl_spa
) == SPA_LOG_CLEAR
||
856 (zilog
->zl_spa
->spa_uberblock
.ub_checkpoint_txg
!= 0 &&
857 zh
->zh_claim_txg
== 0)) {
858 if (!BP_IS_HOLE(&zh
->zh_log
)) {
859 (void) zil_parse(zilog
, zil_clear_log_block
,
860 zil_noop_log_record
, tx
, first_txg
, B_FALSE
);
862 BP_ZERO(&zh
->zh_log
);
863 if (os
->os_encrypted
)
864 os
->os_next_write_raw
[tx
->tx_txg
& TXG_MASK
] = B_TRUE
;
865 dsl_dataset_dirty(dmu_objset_ds(os
), tx
);
866 dmu_objset_disown(os
, B_FALSE
, FTAG
);
871 * If we are not rewinding and opening the pool normally, then
872 * the min_claim_txg should be equal to the first txg of the pool.
874 ASSERT3U(first_txg
, ==, spa_first_txg(zilog
->zl_spa
));
877 * Claim all log blocks if we haven't already done so, and remember
878 * the highest claimed sequence number. This ensures that if we can
879 * read only part of the log now (e.g. due to a missing device),
880 * but we can read the entire log later, we will not try to replay
881 * or destroy beyond the last block we successfully claimed.
883 ASSERT3U(zh
->zh_claim_txg
, <=, first_txg
);
884 if (zh
->zh_claim_txg
== 0 && !BP_IS_HOLE(&zh
->zh_log
)) {
885 (void) zil_parse(zilog
, zil_claim_log_block
,
886 zil_claim_log_record
, tx
, first_txg
, B_FALSE
);
887 zh
->zh_claim_txg
= first_txg
;
888 zh
->zh_claim_blk_seq
= zilog
->zl_parse_blk_seq
;
889 zh
->zh_claim_lr_seq
= zilog
->zl_parse_lr_seq
;
890 if (zilog
->zl_parse_lr_count
|| zilog
->zl_parse_blk_count
> 1)
891 zh
->zh_flags
|= ZIL_REPLAY_NEEDED
;
892 zh
->zh_flags
|= ZIL_CLAIM_LR_SEQ_VALID
;
893 if (os
->os_encrypted
)
894 os
->os_next_write_raw
[tx
->tx_txg
& TXG_MASK
] = B_TRUE
;
895 dsl_dataset_dirty(dmu_objset_ds(os
), tx
);
898 ASSERT3U(first_txg
, ==, (spa_last_synced_txg(zilog
->zl_spa
) + 1));
899 dmu_objset_disown(os
, B_FALSE
, FTAG
);
904 * Check the log by walking the log chain.
905 * Checksum errors are ok as they indicate the end of the chain.
906 * Any other error (no device or read failure) returns an error.
910 zil_check_log_chain(dsl_pool_t
*dp
, dsl_dataset_t
*ds
, void *tx
)
919 error
= dmu_objset_from_ds(ds
, &os
);
921 cmn_err(CE_WARN
, "can't open objset %llu, error %d",
922 (unsigned long long)ds
->ds_object
, error
);
926 zilog
= dmu_objset_zil(os
);
927 bp
= (blkptr_t
*)&zilog
->zl_header
->zh_log
;
929 if (!BP_IS_HOLE(bp
)) {
931 boolean_t valid
= B_TRUE
;
934 * Check the first block and determine if it's on a log device
935 * which may have been removed or faulted prior to loading this
936 * pool. If so, there's no point in checking the rest of the
937 * log as its content should have already been synced to the
940 spa_config_enter(os
->os_spa
, SCL_STATE
, FTAG
, RW_READER
);
941 vd
= vdev_lookup_top(os
->os_spa
, DVA_GET_VDEV(&bp
->blk_dva
[0]));
942 if (vd
->vdev_islog
&& vdev_is_dead(vd
))
943 valid
= vdev_log_state_valid(vd
);
944 spa_config_exit(os
->os_spa
, SCL_STATE
, FTAG
);
950 * Check whether the current uberblock is checkpointed (e.g.
951 * we are rewinding) and whether the current header has been
952 * claimed or not. If it hasn't then skip verifying it. We
953 * do this because its ZIL blocks may be part of the pool's
954 * state before the rewind, which is no longer valid.
956 zil_header_t
*zh
= zil_header_in_syncing_context(zilog
);
957 if (zilog
->zl_spa
->spa_uberblock
.ub_checkpoint_txg
!= 0 &&
958 zh
->zh_claim_txg
== 0)
963 * Because tx == NULL, zil_claim_log_block() will not actually claim
964 * any blocks, but just determine whether it is possible to do so.
965 * In addition to checking the log chain, zil_claim_log_block()
966 * will invoke zio_claim() with a done func of spa_claim_notify(),
967 * which will update spa_max_claim_txg. See spa_load() for details.
969 error
= zil_parse(zilog
, zil_claim_log_block
, zil_claim_log_record
, tx
,
970 zilog
->zl_header
->zh_claim_txg
? -1ULL :
971 spa_min_claim_txg(os
->os_spa
), B_FALSE
);
973 return ((error
== ECKSUM
|| error
== ENOENT
) ? 0 : error
);
977 * When an itx is "skipped", this function is used to properly mark the
978 * waiter as "done, and signal any thread(s) waiting on it. An itx can
979 * be skipped (and not committed to an lwb) for a variety of reasons,
980 * one of them being that the itx was committed via spa_sync(), prior to
981 * it being committed to an lwb; this can happen if a thread calling
982 * zil_commit() is racing with spa_sync().
985 zil_commit_waiter_skip(zil_commit_waiter_t
*zcw
)
987 mutex_enter(&zcw
->zcw_lock
);
988 ASSERT3B(zcw
->zcw_done
, ==, B_FALSE
);
989 zcw
->zcw_done
= B_TRUE
;
990 cv_broadcast(&zcw
->zcw_cv
);
991 mutex_exit(&zcw
->zcw_lock
);
995 * This function is used when the given waiter is to be linked into an
996 * lwb's "lwb_waiter" list; i.e. when the itx is committed to the lwb.
997 * At this point, the waiter will no longer be referenced by the itx,
998 * and instead, will be referenced by the lwb.
1001 zil_commit_waiter_link_lwb(zil_commit_waiter_t
*zcw
, lwb_t
*lwb
)
1004 * The lwb_waiters field of the lwb is protected by the zilog's
1005 * zl_lock, thus it must be held when calling this function.
1007 ASSERT(MUTEX_HELD(&lwb
->lwb_zilog
->zl_lock
));
1009 mutex_enter(&zcw
->zcw_lock
);
1010 ASSERT(!list_link_active(&zcw
->zcw_node
));
1011 ASSERT3P(zcw
->zcw_lwb
, ==, NULL
);
1012 ASSERT3P(lwb
, !=, NULL
);
1013 ASSERT(lwb
->lwb_state
== LWB_STATE_OPENED
||
1014 lwb
->lwb_state
== LWB_STATE_ISSUED
||
1015 lwb
->lwb_state
== LWB_STATE_WRITE_DONE
);
1017 list_insert_tail(&lwb
->lwb_waiters
, zcw
);
1019 mutex_exit(&zcw
->zcw_lock
);
1023 * This function is used when zio_alloc_zil() fails to allocate a ZIL
1024 * block, and the given waiter must be linked to the "nolwb waiters"
1025 * list inside of zil_process_commit_list().
1028 zil_commit_waiter_link_nolwb(zil_commit_waiter_t
*zcw
, list_t
*nolwb
)
1030 mutex_enter(&zcw
->zcw_lock
);
1031 ASSERT(!list_link_active(&zcw
->zcw_node
));
1032 ASSERT3P(zcw
->zcw_lwb
, ==, NULL
);
1033 list_insert_tail(nolwb
, zcw
);
1034 mutex_exit(&zcw
->zcw_lock
);
1038 zil_lwb_add_block(lwb_t
*lwb
, const blkptr_t
*bp
)
1040 avl_tree_t
*t
= &lwb
->lwb_vdev_tree
;
1042 zil_vdev_node_t
*zv
, zvsearch
;
1043 int ndvas
= BP_GET_NDVAS(bp
);
1046 if (zil_nocacheflush
)
1049 mutex_enter(&lwb
->lwb_vdev_lock
);
1050 for (i
= 0; i
< ndvas
; i
++) {
1051 zvsearch
.zv_vdev
= DVA_GET_VDEV(&bp
->blk_dva
[i
]);
1052 if (avl_find(t
, &zvsearch
, &where
) == NULL
) {
1053 zv
= kmem_alloc(sizeof (*zv
), KM_SLEEP
);
1054 zv
->zv_vdev
= zvsearch
.zv_vdev
;
1055 avl_insert(t
, zv
, where
);
1058 mutex_exit(&lwb
->lwb_vdev_lock
);
1062 zil_lwb_flush_defer(lwb_t
*lwb
, lwb_t
*nlwb
)
1064 avl_tree_t
*src
= &lwb
->lwb_vdev_tree
;
1065 avl_tree_t
*dst
= &nlwb
->lwb_vdev_tree
;
1066 void *cookie
= NULL
;
1067 zil_vdev_node_t
*zv
;
1069 ASSERT3S(lwb
->lwb_state
, ==, LWB_STATE_WRITE_DONE
);
1070 ASSERT3S(nlwb
->lwb_state
, !=, LWB_STATE_WRITE_DONE
);
1071 ASSERT3S(nlwb
->lwb_state
, !=, LWB_STATE_FLUSH_DONE
);
1074 * While 'lwb' is at a point in its lifetime where lwb_vdev_tree does
1075 * not need the protection of lwb_vdev_lock (it will only be modified
1076 * while holding zilog->zl_lock) as its writes and those of its
1077 * children have all completed. The younger 'nlwb' may be waiting on
1078 * future writes to additional vdevs.
1080 mutex_enter(&nlwb
->lwb_vdev_lock
);
1082 * Tear down the 'lwb' vdev tree, ensuring that entries which do not
1083 * exist in 'nlwb' are moved to it, freeing any would-be duplicates.
1085 while ((zv
= avl_destroy_nodes(src
, &cookie
)) != NULL
) {
1088 if (avl_find(dst
, zv
, &where
) == NULL
) {
1089 avl_insert(dst
, zv
, where
);
1091 kmem_free(zv
, sizeof (*zv
));
1094 mutex_exit(&nlwb
->lwb_vdev_lock
);
1098 zil_lwb_add_txg(lwb_t
*lwb
, uint64_t txg
)
1100 lwb
->lwb_max_txg
= MAX(lwb
->lwb_max_txg
, txg
);
1104 * This function is a called after all vdevs associated with a given lwb
1105 * write have completed their DKIOCFLUSHWRITECACHE command; or as soon
1106 * as the lwb write completes, if "zil_nocacheflush" is set. Further,
1107 * all "previous" lwb's will have completed before this function is
1108 * called; i.e. this function is called for all previous lwbs before
1109 * it's called for "this" lwb (enforced via zio the dependencies
1110 * configured in zil_lwb_set_zio_dependency()).
1112 * The intention is for this function to be called as soon as the
1113 * contents of an lwb are considered "stable" on disk, and will survive
1114 * any sudden loss of power. At this point, any threads waiting for the
1115 * lwb to reach this state are signalled, and the "waiter" structures
1116 * are marked "done".
1119 zil_lwb_flush_vdevs_done(zio_t
*zio
)
1121 lwb_t
*lwb
= zio
->io_private
;
1122 zilog_t
*zilog
= lwb
->lwb_zilog
;
1123 dmu_tx_t
*tx
= lwb
->lwb_tx
;
1124 zil_commit_waiter_t
*zcw
;
1127 spa_config_exit(zilog
->zl_spa
, SCL_STATE
, lwb
);
1129 zio_buf_free(lwb
->lwb_buf
, lwb
->lwb_sz
);
1131 mutex_enter(&zilog
->zl_lock
);
1134 * Ensure the lwb buffer pointer is cleared before releasing the
1135 * txg. If we have had an allocation failure and the txg is
1136 * waiting to sync then we want zil_sync() to remove the lwb so
1137 * that it's not picked up as the next new one in
1138 * zil_process_commit_list(). zil_sync() will only remove the
1139 * lwb if lwb_buf is null.
1141 lwb
->lwb_buf
= NULL
;
1144 ASSERT3U(lwb
->lwb_issued_timestamp
, >, 0);
1145 zilog
->zl_last_lwb_latency
= gethrtime() - lwb
->lwb_issued_timestamp
;
1147 lwb
->lwb_root_zio
= NULL
;
1149 ASSERT3S(lwb
->lwb_state
, ==, LWB_STATE_WRITE_DONE
);
1150 lwb
->lwb_state
= LWB_STATE_FLUSH_DONE
;
1152 if (zilog
->zl_last_lwb_opened
== lwb
) {
1154 * Remember the highest committed log sequence number
1155 * for ztest. We only update this value when all the log
1156 * writes succeeded, because ztest wants to ASSERT that
1157 * it got the whole log chain.
1159 zilog
->zl_commit_lr_seq
= zilog
->zl_lr_seq
;
1162 while ((itx
= list_head(&lwb
->lwb_itxs
)) != NULL
) {
1163 list_remove(&lwb
->lwb_itxs
, itx
);
1164 zil_itx_destroy(itx
);
1167 while ((zcw
= list_head(&lwb
->lwb_waiters
)) != NULL
) {
1168 mutex_enter(&zcw
->zcw_lock
);
1170 ASSERT(list_link_active(&zcw
->zcw_node
));
1171 list_remove(&lwb
->lwb_waiters
, zcw
);
1173 ASSERT3P(zcw
->zcw_lwb
, ==, lwb
);
1174 zcw
->zcw_lwb
= NULL
;
1176 zcw
->zcw_zio_error
= zio
->io_error
;
1178 ASSERT3B(zcw
->zcw_done
, ==, B_FALSE
);
1179 zcw
->zcw_done
= B_TRUE
;
1180 cv_broadcast(&zcw
->zcw_cv
);
1182 mutex_exit(&zcw
->zcw_lock
);
1185 mutex_exit(&zilog
->zl_lock
);
1188 * Now that we've written this log block, we have a stable pointer
1189 * to the next block in the chain, so it's OK to let the txg in
1190 * which we allocated the next block sync.
1196 * This is called when an lwb's write zio completes. The callback's
1197 * purpose is to issue the DKIOCFLUSHWRITECACHE commands for the vdevs
1198 * in the lwb's lwb_vdev_tree. The tree will contain the vdevs involved
1199 * in writing out this specific lwb's data, and in the case that cache
1200 * flushes have been deferred, vdevs involved in writing the data for
1201 * previous lwbs. The writes corresponding to all the vdevs in the
1202 * lwb_vdev_tree will have completed by the time this is called, due to
1203 * the zio dependencies configured in zil_lwb_set_zio_dependency(),
1204 * which takes deferred flushes into account. The lwb will be "done"
1205 * once zil_lwb_flush_vdevs_done() is called, which occurs in the zio
1206 * completion callback for the lwb's root zio.
1209 zil_lwb_write_done(zio_t
*zio
)
1211 lwb_t
*lwb
= zio
->io_private
;
1212 spa_t
*spa
= zio
->io_spa
;
1213 zilog_t
*zilog
= lwb
->lwb_zilog
;
1214 avl_tree_t
*t
= &lwb
->lwb_vdev_tree
;
1215 void *cookie
= NULL
;
1216 zil_vdev_node_t
*zv
;
1219 ASSERT3S(spa_config_held(spa
, SCL_STATE
, RW_READER
), !=, 0);
1221 ASSERT(BP_GET_COMPRESS(zio
->io_bp
) == ZIO_COMPRESS_OFF
);
1222 ASSERT(BP_GET_TYPE(zio
->io_bp
) == DMU_OT_INTENT_LOG
);
1223 ASSERT(BP_GET_LEVEL(zio
->io_bp
) == 0);
1224 ASSERT(BP_GET_BYTEORDER(zio
->io_bp
) == ZFS_HOST_BYTEORDER
);
1225 ASSERT(!BP_IS_GANG(zio
->io_bp
));
1226 ASSERT(!BP_IS_HOLE(zio
->io_bp
));
1227 ASSERT(BP_GET_FILL(zio
->io_bp
) == 0);
1229 abd_put(zio
->io_abd
);
1231 mutex_enter(&zilog
->zl_lock
);
1232 ASSERT3S(lwb
->lwb_state
, ==, LWB_STATE_ISSUED
);
1233 lwb
->lwb_state
= LWB_STATE_WRITE_DONE
;
1234 lwb
->lwb_write_zio
= NULL
;
1235 lwb
->lwb_fastwrite
= FALSE
;
1236 nlwb
= list_next(&zilog
->zl_lwb_list
, lwb
);
1237 mutex_exit(&zilog
->zl_lock
);
1239 if (avl_numnodes(t
) == 0)
1243 * If there was an IO error, we're not going to call zio_flush()
1244 * on these vdevs, so we simply empty the tree and free the
1245 * nodes. We avoid calling zio_flush() since there isn't any
1246 * good reason for doing so, after the lwb block failed to be
1249 if (zio
->io_error
!= 0) {
1250 while ((zv
= avl_destroy_nodes(t
, &cookie
)) != NULL
)
1251 kmem_free(zv
, sizeof (*zv
));
1256 * If this lwb does not have any threads waiting for it to
1257 * complete, we want to defer issuing the DKIOCFLUSHWRITECACHE
1258 * command to the vdevs written to by "this" lwb, and instead
1259 * rely on the "next" lwb to handle the DKIOCFLUSHWRITECACHE
1260 * command for those vdevs. Thus, we merge the vdev tree of
1261 * "this" lwb with the vdev tree of the "next" lwb in the list,
1262 * and assume the "next" lwb will handle flushing the vdevs (or
1263 * deferring the flush(s) again).
1265 * This is a useful performance optimization, especially for
1266 * workloads with lots of async write activity and few sync
1267 * write and/or fsync activity, as it has the potential to
1268 * coalesce multiple flush commands to a vdev into one.
1270 if (list_head(&lwb
->lwb_waiters
) == NULL
&& nlwb
!= NULL
) {
1271 zil_lwb_flush_defer(lwb
, nlwb
);
1272 ASSERT(avl_is_empty(&lwb
->lwb_vdev_tree
));
1276 while ((zv
= avl_destroy_nodes(t
, &cookie
)) != NULL
) {
1277 vdev_t
*vd
= vdev_lookup_top(spa
, zv
->zv_vdev
);
1279 zio_flush(lwb
->lwb_root_zio
, vd
);
1280 kmem_free(zv
, sizeof (*zv
));
1285 zil_lwb_set_zio_dependency(zilog_t
*zilog
, lwb_t
*lwb
)
1287 lwb_t
*last_lwb_opened
= zilog
->zl_last_lwb_opened
;
1289 ASSERT(MUTEX_HELD(&zilog
->zl_issuer_lock
));
1290 ASSERT(MUTEX_HELD(&zilog
->zl_lock
));
1293 * The zilog's "zl_last_lwb_opened" field is used to build the
1294 * lwb/zio dependency chain, which is used to preserve the
1295 * ordering of lwb completions that is required by the semantics
1296 * of the ZIL. Each new lwb zio becomes a parent of the
1297 * "previous" lwb zio, such that the new lwb's zio cannot
1298 * complete until the "previous" lwb's zio completes.
1300 * This is required by the semantics of zil_commit(); the commit
1301 * waiters attached to the lwbs will be woken in the lwb zio's
1302 * completion callback, so this zio dependency graph ensures the
1303 * waiters are woken in the correct order (the same order the
1304 * lwbs were created).
1306 if (last_lwb_opened
!= NULL
&&
1307 last_lwb_opened
->lwb_state
!= LWB_STATE_FLUSH_DONE
) {
1308 ASSERT(last_lwb_opened
->lwb_state
== LWB_STATE_OPENED
||
1309 last_lwb_opened
->lwb_state
== LWB_STATE_ISSUED
||
1310 last_lwb_opened
->lwb_state
== LWB_STATE_WRITE_DONE
);
1312 ASSERT3P(last_lwb_opened
->lwb_root_zio
, !=, NULL
);
1313 zio_add_child(lwb
->lwb_root_zio
,
1314 last_lwb_opened
->lwb_root_zio
);
1317 * If the previous lwb's write hasn't already completed,
1318 * we also want to order the completion of the lwb write
1319 * zios (above, we only order the completion of the lwb
1320 * root zios). This is required because of how we can
1321 * defer the DKIOCFLUSHWRITECACHE commands for each lwb.
1323 * When the DKIOCFLUSHWRITECACHE commands are deferred,
1324 * the previous lwb will rely on this lwb to flush the
1325 * vdevs written to by that previous lwb. Thus, we need
1326 * to ensure this lwb doesn't issue the flush until
1327 * after the previous lwb's write completes. We ensure
1328 * this ordering by setting the zio parent/child
1329 * relationship here.
1331 * Without this relationship on the lwb's write zio,
1332 * it's possible for this lwb's write to complete prior
1333 * to the previous lwb's write completing; and thus, the
1334 * vdevs for the previous lwb would be flushed prior to
1335 * that lwb's data being written to those vdevs (the
1336 * vdevs are flushed in the lwb write zio's completion
1337 * handler, zil_lwb_write_done()).
1339 if (last_lwb_opened
->lwb_state
!= LWB_STATE_WRITE_DONE
) {
1340 ASSERT(last_lwb_opened
->lwb_state
== LWB_STATE_OPENED
||
1341 last_lwb_opened
->lwb_state
== LWB_STATE_ISSUED
);
1343 ASSERT3P(last_lwb_opened
->lwb_write_zio
, !=, NULL
);
1344 zio_add_child(lwb
->lwb_write_zio
,
1345 last_lwb_opened
->lwb_write_zio
);
1352 * This function's purpose is to "open" an lwb such that it is ready to
1353 * accept new itxs being committed to it. To do this, the lwb's zio
1354 * structures are created, and linked to the lwb. This function is
1355 * idempotent; if the passed in lwb has already been opened, this
1356 * function is essentially a no-op.
1359 zil_lwb_write_open(zilog_t
*zilog
, lwb_t
*lwb
)
1361 zbookmark_phys_t zb
;
1362 zio_priority_t prio
;
1364 ASSERT(MUTEX_HELD(&zilog
->zl_issuer_lock
));
1365 ASSERT3P(lwb
, !=, NULL
);
1366 EQUIV(lwb
->lwb_root_zio
== NULL
, lwb
->lwb_state
== LWB_STATE_CLOSED
);
1367 EQUIV(lwb
->lwb_root_zio
!= NULL
, lwb
->lwb_state
== LWB_STATE_OPENED
);
1369 SET_BOOKMARK(&zb
, lwb
->lwb_blk
.blk_cksum
.zc_word
[ZIL_ZC_OBJSET
],
1370 ZB_ZIL_OBJECT
, ZB_ZIL_LEVEL
,
1371 lwb
->lwb_blk
.blk_cksum
.zc_word
[ZIL_ZC_SEQ
]);
1373 /* Lock so zil_sync() doesn't fastwrite_unmark after zio is created */
1374 mutex_enter(&zilog
->zl_lock
);
1375 if (lwb
->lwb_root_zio
== NULL
) {
1376 abd_t
*lwb_abd
= abd_get_from_buf(lwb
->lwb_buf
,
1377 BP_GET_LSIZE(&lwb
->lwb_blk
));
1379 if (!lwb
->lwb_fastwrite
) {
1380 metaslab_fastwrite_mark(zilog
->zl_spa
, &lwb
->lwb_blk
);
1381 lwb
->lwb_fastwrite
= 1;
1384 if (!lwb
->lwb_slog
|| zilog
->zl_cur_used
<= zil_slog_bulk
)
1385 prio
= ZIO_PRIORITY_SYNC_WRITE
;
1387 prio
= ZIO_PRIORITY_ASYNC_WRITE
;
1389 lwb
->lwb_root_zio
= zio_root(zilog
->zl_spa
,
1390 zil_lwb_flush_vdevs_done
, lwb
, ZIO_FLAG_CANFAIL
);
1391 ASSERT3P(lwb
->lwb_root_zio
, !=, NULL
);
1393 lwb
->lwb_write_zio
= zio_rewrite(lwb
->lwb_root_zio
,
1394 zilog
->zl_spa
, 0, &lwb
->lwb_blk
, lwb_abd
,
1395 BP_GET_LSIZE(&lwb
->lwb_blk
), zil_lwb_write_done
, lwb
,
1396 prio
, ZIO_FLAG_CANFAIL
| ZIO_FLAG_DONT_PROPAGATE
|
1397 ZIO_FLAG_FASTWRITE
, &zb
);
1398 ASSERT3P(lwb
->lwb_write_zio
, !=, NULL
);
1400 lwb
->lwb_state
= LWB_STATE_OPENED
;
1402 zil_lwb_set_zio_dependency(zilog
, lwb
);
1403 zilog
->zl_last_lwb_opened
= lwb
;
1405 mutex_exit(&zilog
->zl_lock
);
1407 ASSERT3P(lwb
->lwb_root_zio
, !=, NULL
);
1408 ASSERT3P(lwb
->lwb_write_zio
, !=, NULL
);
1409 ASSERT3S(lwb
->lwb_state
, ==, LWB_STATE_OPENED
);
1413 * Define a limited set of intent log block sizes.
1415 * These must be a multiple of 4KB. Note only the amount used (again
1416 * aligned to 4KB) actually gets written. However, we can't always just
1417 * allocate SPA_OLD_MAXBLOCKSIZE as the slog space could be exhausted.
1419 uint64_t zil_block_buckets
[] = {
1420 4096, /* non TX_WRITE */
1421 8192+4096, /* data base */
1422 32*1024 + 4096, /* NFS writes */
1427 * Start a log block write and advance to the next log block.
1428 * Calls are serialized.
1431 zil_lwb_write_issue(zilog_t
*zilog
, lwb_t
*lwb
)
1435 spa_t
*spa
= zilog
->zl_spa
;
1439 uint64_t zil_blksz
, wsz
;
1443 ASSERT(MUTEX_HELD(&zilog
->zl_issuer_lock
));
1444 ASSERT3P(lwb
->lwb_root_zio
, !=, NULL
);
1445 ASSERT3P(lwb
->lwb_write_zio
, !=, NULL
);
1446 ASSERT3S(lwb
->lwb_state
, ==, LWB_STATE_OPENED
);
1448 if (BP_GET_CHECKSUM(&lwb
->lwb_blk
) == ZIO_CHECKSUM_ZILOG2
) {
1449 zilc
= (zil_chain_t
*)lwb
->lwb_buf
;
1450 bp
= &zilc
->zc_next_blk
;
1452 zilc
= (zil_chain_t
*)(lwb
->lwb_buf
+ lwb
->lwb_sz
);
1453 bp
= &zilc
->zc_next_blk
;
1456 ASSERT(lwb
->lwb_nused
<= lwb
->lwb_sz
);
1459 * Allocate the next block and save its address in this block
1460 * before writing it in order to establish the log chain.
1461 * Note that if the allocation of nlwb synced before we wrote
1462 * the block that points at it (lwb), we'd leak it if we crashed.
1463 * Therefore, we don't do dmu_tx_commit() until zil_lwb_write_done().
1464 * We dirty the dataset to ensure that zil_sync() will be called
1465 * to clean up in the event of allocation failure or I/O failure.
1468 tx
= dmu_tx_create(zilog
->zl_os
);
1471 * Since we are not going to create any new dirty data, and we
1472 * can even help with clearing the existing dirty data, we
1473 * should not be subject to the dirty data based delays. We
1474 * use TXG_NOTHROTTLE to bypass the delay mechanism.
1476 VERIFY0(dmu_tx_assign(tx
, TXG_WAIT
| TXG_NOTHROTTLE
));
1478 dsl_dataset_dirty(dmu_objset_ds(zilog
->zl_os
), tx
);
1479 txg
= dmu_tx_get_txg(tx
);
1484 * Log blocks are pre-allocated. Here we select the size of the next
1485 * block, based on size used in the last block.
1486 * - first find the smallest bucket that will fit the block from a
1487 * limited set of block sizes. This is because it's faster to write
1488 * blocks allocated from the same metaslab as they are adjacent or
1490 * - next find the maximum from the new suggested size and an array of
1491 * previous sizes. This lessens a picket fence effect of wrongly
1492 * guessing the size if we have a stream of say 2k, 64k, 2k, 64k
1495 * Note we only write what is used, but we can't just allocate
1496 * the maximum block size because we can exhaust the available
1499 zil_blksz
= zilog
->zl_cur_used
+ sizeof (zil_chain_t
);
1500 for (i
= 0; zil_blksz
> zil_block_buckets
[i
]; i
++)
1502 zil_blksz
= zil_block_buckets
[i
];
1503 if (zil_blksz
== UINT64_MAX
)
1504 zil_blksz
= SPA_OLD_MAXBLOCKSIZE
;
1505 zilog
->zl_prev_blks
[zilog
->zl_prev_rotor
] = zil_blksz
;
1506 for (i
= 0; i
< ZIL_PREV_BLKS
; i
++)
1507 zil_blksz
= MAX(zil_blksz
, zilog
->zl_prev_blks
[i
]);
1508 zilog
->zl_prev_rotor
= (zilog
->zl_prev_rotor
+ 1) & (ZIL_PREV_BLKS
- 1);
1511 error
= zio_alloc_zil(spa
, zilog
->zl_os
, txg
, bp
, zil_blksz
, &slog
);
1513 ZIL_STAT_BUMP(zil_itx_metaslab_slog_count
);
1514 ZIL_STAT_INCR(zil_itx_metaslab_slog_bytes
, lwb
->lwb_nused
);
1516 ZIL_STAT_BUMP(zil_itx_metaslab_normal_count
);
1517 ZIL_STAT_INCR(zil_itx_metaslab_normal_bytes
, lwb
->lwb_nused
);
1520 ASSERT3U(bp
->blk_birth
, ==, txg
);
1521 bp
->blk_cksum
= lwb
->lwb_blk
.blk_cksum
;
1522 bp
->blk_cksum
.zc_word
[ZIL_ZC_SEQ
]++;
1525 * Allocate a new log write block (lwb).
1527 nlwb
= zil_alloc_lwb(zilog
, bp
, slog
, txg
, TRUE
);
1530 if (BP_GET_CHECKSUM(&lwb
->lwb_blk
) == ZIO_CHECKSUM_ZILOG2
) {
1531 /* For Slim ZIL only write what is used. */
1532 wsz
= P2ROUNDUP_TYPED(lwb
->lwb_nused
, ZIL_MIN_BLKSZ
, uint64_t);
1533 ASSERT3U(wsz
, <=, lwb
->lwb_sz
);
1534 zio_shrink(lwb
->lwb_write_zio
, wsz
);
1541 zilc
->zc_nused
= lwb
->lwb_nused
;
1542 zilc
->zc_eck
.zec_cksum
= lwb
->lwb_blk
.blk_cksum
;
1545 * clear unused data for security
1547 bzero(lwb
->lwb_buf
+ lwb
->lwb_nused
, wsz
- lwb
->lwb_nused
);
1549 spa_config_enter(zilog
->zl_spa
, SCL_STATE
, lwb
, RW_READER
);
1551 zil_lwb_add_block(lwb
, &lwb
->lwb_blk
);
1552 lwb
->lwb_issued_timestamp
= gethrtime();
1553 lwb
->lwb_state
= LWB_STATE_ISSUED
;
1555 zio_nowait(lwb
->lwb_root_zio
);
1556 zio_nowait(lwb
->lwb_write_zio
);
1559 * If there was an allocation failure then nlwb will be null which
1560 * forces a txg_wait_synced().
1566 zil_lwb_commit(zilog_t
*zilog
, itx_t
*itx
, lwb_t
*lwb
)
1569 lr_write_t
*lrwb
, *lrw
;
1571 uint64_t dlen
, dnow
, lwb_sp
, reclen
, txg
;
1573 ASSERT(MUTEX_HELD(&zilog
->zl_issuer_lock
));
1574 ASSERT3P(lwb
, !=, NULL
);
1575 ASSERT3P(lwb
->lwb_buf
, !=, NULL
);
1577 zil_lwb_write_open(zilog
, lwb
);
1580 lrw
= (lr_write_t
*)lrc
;
1583 * A commit itx doesn't represent any on-disk state; instead
1584 * it's simply used as a place holder on the commit list, and
1585 * provides a mechanism for attaching a "commit waiter" onto the
1586 * correct lwb (such that the waiter can be signalled upon
1587 * completion of that lwb). Thus, we don't process this itx's
1588 * log record if it's a commit itx (these itx's don't have log
1589 * records), and instead link the itx's waiter onto the lwb's
1592 * For more details, see the comment above zil_commit().
1594 if (lrc
->lrc_txtype
== TX_COMMIT
) {
1595 mutex_enter(&zilog
->zl_lock
);
1596 zil_commit_waiter_link_lwb(itx
->itx_private
, lwb
);
1597 itx
->itx_private
= NULL
;
1598 mutex_exit(&zilog
->zl_lock
);
1602 if (lrc
->lrc_txtype
== TX_WRITE
&& itx
->itx_wr_state
== WR_NEED_COPY
) {
1603 dlen
= P2ROUNDUP_TYPED(
1604 lrw
->lr_length
, sizeof (uint64_t), uint64_t);
1608 reclen
= lrc
->lrc_reclen
;
1609 zilog
->zl_cur_used
+= (reclen
+ dlen
);
1612 ASSERT3U(zilog
->zl_cur_used
, <, UINT64_MAX
- (reclen
+ dlen
));
1616 * If this record won't fit in the current log block, start a new one.
1617 * For WR_NEED_COPY optimize layout for minimal number of chunks.
1619 lwb_sp
= lwb
->lwb_sz
- lwb
->lwb_nused
;
1620 if (reclen
> lwb_sp
|| (reclen
+ dlen
> lwb_sp
&&
1621 lwb_sp
< ZIL_MAX_WASTE_SPACE
&& (dlen
% ZIL_MAX_LOG_DATA
== 0 ||
1622 lwb_sp
< reclen
+ dlen
% ZIL_MAX_LOG_DATA
))) {
1623 lwb
= zil_lwb_write_issue(zilog
, lwb
);
1626 zil_lwb_write_open(zilog
, lwb
);
1627 ASSERT(LWB_EMPTY(lwb
));
1628 lwb_sp
= lwb
->lwb_sz
- lwb
->lwb_nused
;
1629 ASSERT3U(reclen
+ MIN(dlen
, sizeof (uint64_t)), <=, lwb_sp
);
1632 dnow
= MIN(dlen
, lwb_sp
- reclen
);
1633 lr_buf
= lwb
->lwb_buf
+ lwb
->lwb_nused
;
1634 bcopy(lrc
, lr_buf
, reclen
);
1635 lrcb
= (lr_t
*)lr_buf
; /* Like lrc, but inside lwb. */
1636 lrwb
= (lr_write_t
*)lrcb
; /* Like lrw, but inside lwb. */
1638 ZIL_STAT_BUMP(zil_itx_count
);
1641 * If it's a write, fetch the data or get its blkptr as appropriate.
1643 if (lrc
->lrc_txtype
== TX_WRITE
) {
1644 if (txg
> spa_freeze_txg(zilog
->zl_spa
))
1645 txg_wait_synced(zilog
->zl_dmu_pool
, txg
);
1646 if (itx
->itx_wr_state
== WR_COPIED
) {
1647 ZIL_STAT_BUMP(zil_itx_copied_count
);
1648 ZIL_STAT_INCR(zil_itx_copied_bytes
, lrw
->lr_length
);
1653 if (itx
->itx_wr_state
== WR_NEED_COPY
) {
1654 dbuf
= lr_buf
+ reclen
;
1655 lrcb
->lrc_reclen
+= dnow
;
1656 if (lrwb
->lr_length
> dnow
)
1657 lrwb
->lr_length
= dnow
;
1658 lrw
->lr_offset
+= dnow
;
1659 lrw
->lr_length
-= dnow
;
1660 ZIL_STAT_BUMP(zil_itx_needcopy_count
);
1661 ZIL_STAT_INCR(zil_itx_needcopy_bytes
, dnow
);
1663 ASSERT3S(itx
->itx_wr_state
, ==, WR_INDIRECT
);
1665 ZIL_STAT_BUMP(zil_itx_indirect_count
);
1666 ZIL_STAT_INCR(zil_itx_indirect_bytes
,
1671 * We pass in the "lwb_write_zio" rather than
1672 * "lwb_root_zio" so that the "lwb_write_zio"
1673 * becomes the parent of any zio's created by
1674 * the "zl_get_data" callback. The vdevs are
1675 * flushed after the "lwb_write_zio" completes,
1676 * so we want to make sure that completion
1677 * callback waits for these additional zio's,
1678 * such that the vdevs used by those zio's will
1679 * be included in the lwb's vdev tree, and those
1680 * vdevs will be properly flushed. If we passed
1681 * in "lwb_root_zio" here, then these additional
1682 * vdevs may not be flushed; e.g. if these zio's
1683 * completed after "lwb_write_zio" completed.
1685 error
= zilog
->zl_get_data(itx
->itx_private
,
1686 lrwb
, dbuf
, lwb
, lwb
->lwb_write_zio
);
1689 txg_wait_synced(zilog
->zl_dmu_pool
, txg
);
1693 ASSERT(error
== ENOENT
|| error
== EEXIST
||
1701 * We're actually making an entry, so update lrc_seq to be the
1702 * log record sequence number. Note that this is generally not
1703 * equal to the itx sequence number because not all transactions
1704 * are synchronous, and sometimes spa_sync() gets there first.
1706 lrcb
->lrc_seq
= ++zilog
->zl_lr_seq
;
1707 lwb
->lwb_nused
+= reclen
+ dnow
;
1709 zil_lwb_add_txg(lwb
, txg
);
1711 ASSERT3U(lwb
->lwb_nused
, <=, lwb
->lwb_sz
);
1712 ASSERT0(P2PHASE(lwb
->lwb_nused
, sizeof (uint64_t)));
1716 zilog
->zl_cur_used
+= reclen
;
1724 zil_itx_create(uint64_t txtype
, size_t lrsize
)
1729 lrsize
= P2ROUNDUP_TYPED(lrsize
, sizeof (uint64_t), size_t);
1730 itxsize
= offsetof(itx_t
, itx_lr
) + lrsize
;
1732 itx
= zio_data_buf_alloc(itxsize
);
1733 itx
->itx_lr
.lrc_txtype
= txtype
;
1734 itx
->itx_lr
.lrc_reclen
= lrsize
;
1735 itx
->itx_lr
.lrc_seq
= 0; /* defensive */
1736 itx
->itx_sync
= B_TRUE
; /* default is synchronous */
1737 itx
->itx_callback
= NULL
;
1738 itx
->itx_callback_data
= NULL
;
1739 itx
->itx_size
= itxsize
;
1745 zil_itx_destroy(itx_t
*itx
)
1747 IMPLY(itx
->itx_lr
.lrc_txtype
== TX_COMMIT
, itx
->itx_callback
== NULL
);
1748 IMPLY(itx
->itx_callback
!= NULL
, itx
->itx_lr
.lrc_txtype
!= TX_COMMIT
);
1750 if (itx
->itx_callback
!= NULL
)
1751 itx
->itx_callback(itx
->itx_callback_data
);
1753 zio_data_buf_free(itx
, itx
->itx_size
);
1757 * Free up the sync and async itxs. The itxs_t has already been detached
1758 * so no locks are needed.
1761 zil_itxg_clean(itxs_t
*itxs
)
1767 itx_async_node_t
*ian
;
1769 list
= &itxs
->i_sync_list
;
1770 while ((itx
= list_head(list
)) != NULL
) {
1772 * In the general case, commit itxs will not be found
1773 * here, as they'll be committed to an lwb via
1774 * zil_lwb_commit(), and free'd in that function. Having
1775 * said that, it is still possible for commit itxs to be
1776 * found here, due to the following race:
1778 * - a thread calls zil_commit() which assigns the
1779 * commit itx to a per-txg i_sync_list
1780 * - zil_itxg_clean() is called (e.g. via spa_sync())
1781 * while the waiter is still on the i_sync_list
1783 * There's nothing to prevent syncing the txg while the
1784 * waiter is on the i_sync_list. This normally doesn't
1785 * happen because spa_sync() is slower than zil_commit(),
1786 * but if zil_commit() calls txg_wait_synced() (e.g.
1787 * because zil_create() or zil_commit_writer_stall() is
1788 * called) we will hit this case.
1790 if (itx
->itx_lr
.lrc_txtype
== TX_COMMIT
)
1791 zil_commit_waiter_skip(itx
->itx_private
);
1793 list_remove(list
, itx
);
1794 zil_itx_destroy(itx
);
1798 t
= &itxs
->i_async_tree
;
1799 while ((ian
= avl_destroy_nodes(t
, &cookie
)) != NULL
) {
1800 list
= &ian
->ia_list
;
1801 while ((itx
= list_head(list
)) != NULL
) {
1802 list_remove(list
, itx
);
1803 /* commit itxs should never be on the async lists. */
1804 ASSERT3U(itx
->itx_lr
.lrc_txtype
, !=, TX_COMMIT
);
1805 zil_itx_destroy(itx
);
1808 kmem_free(ian
, sizeof (itx_async_node_t
));
1812 kmem_free(itxs
, sizeof (itxs_t
));
1816 zil_aitx_compare(const void *x1
, const void *x2
)
1818 const uint64_t o1
= ((itx_async_node_t
*)x1
)->ia_foid
;
1819 const uint64_t o2
= ((itx_async_node_t
*)x2
)->ia_foid
;
1821 return (AVL_CMP(o1
, o2
));
1825 * Remove all async itx with the given oid.
1828 zil_remove_async(zilog_t
*zilog
, uint64_t oid
)
1831 itx_async_node_t
*ian
;
1838 list_create(&clean_list
, sizeof (itx_t
), offsetof(itx_t
, itx_node
));
1840 if (spa_freeze_txg(zilog
->zl_spa
) != UINT64_MAX
) /* ziltest support */
1843 otxg
= spa_last_synced_txg(zilog
->zl_spa
) + 1;
1845 for (txg
= otxg
; txg
< (otxg
+ TXG_CONCURRENT_STATES
); txg
++) {
1846 itxg_t
*itxg
= &zilog
->zl_itxg
[txg
& TXG_MASK
];
1848 mutex_enter(&itxg
->itxg_lock
);
1849 if (itxg
->itxg_txg
!= txg
) {
1850 mutex_exit(&itxg
->itxg_lock
);
1855 * Locate the object node and append its list.
1857 t
= &itxg
->itxg_itxs
->i_async_tree
;
1858 ian
= avl_find(t
, &oid
, &where
);
1860 list_move_tail(&clean_list
, &ian
->ia_list
);
1861 mutex_exit(&itxg
->itxg_lock
);
1863 while ((itx
= list_head(&clean_list
)) != NULL
) {
1864 list_remove(&clean_list
, itx
);
1865 /* commit itxs should never be on the async lists. */
1866 ASSERT3U(itx
->itx_lr
.lrc_txtype
, !=, TX_COMMIT
);
1867 zil_itx_destroy(itx
);
1869 list_destroy(&clean_list
);
1873 zil_itx_assign(zilog_t
*zilog
, itx_t
*itx
, dmu_tx_t
*tx
)
1877 itxs_t
*itxs
, *clean
= NULL
;
1880 * Object ids can be re-instantiated in the next txg so
1881 * remove any async transactions to avoid future leaks.
1882 * This can happen if a fsync occurs on the re-instantiated
1883 * object for a WR_INDIRECT or WR_NEED_COPY write, which gets
1884 * the new file data and flushes a write record for the old object.
1886 if ((itx
->itx_lr
.lrc_txtype
& ~TX_CI
) == TX_REMOVE
)
1887 zil_remove_async(zilog
, itx
->itx_oid
);
1890 * Ensure the data of a renamed file is committed before the rename.
1892 if ((itx
->itx_lr
.lrc_txtype
& ~TX_CI
) == TX_RENAME
)
1893 zil_async_to_sync(zilog
, itx
->itx_oid
);
1895 if (spa_freeze_txg(zilog
->zl_spa
) != UINT64_MAX
)
1898 txg
= dmu_tx_get_txg(tx
);
1900 itxg
= &zilog
->zl_itxg
[txg
& TXG_MASK
];
1901 mutex_enter(&itxg
->itxg_lock
);
1902 itxs
= itxg
->itxg_itxs
;
1903 if (itxg
->itxg_txg
!= txg
) {
1906 * The zil_clean callback hasn't got around to cleaning
1907 * this itxg. Save the itxs for release below.
1908 * This should be rare.
1910 zfs_dbgmsg("zil_itx_assign: missed itx cleanup for "
1911 "txg %llu", itxg
->itxg_txg
);
1912 clean
= itxg
->itxg_itxs
;
1914 itxg
->itxg_txg
= txg
;
1915 itxs
= itxg
->itxg_itxs
= kmem_zalloc(sizeof (itxs_t
),
1918 list_create(&itxs
->i_sync_list
, sizeof (itx_t
),
1919 offsetof(itx_t
, itx_node
));
1920 avl_create(&itxs
->i_async_tree
, zil_aitx_compare
,
1921 sizeof (itx_async_node_t
),
1922 offsetof(itx_async_node_t
, ia_node
));
1924 if (itx
->itx_sync
) {
1925 list_insert_tail(&itxs
->i_sync_list
, itx
);
1927 avl_tree_t
*t
= &itxs
->i_async_tree
;
1929 LR_FOID_GET_OBJ(((lr_ooo_t
*)&itx
->itx_lr
)->lr_foid
);
1930 itx_async_node_t
*ian
;
1933 ian
= avl_find(t
, &foid
, &where
);
1935 ian
= kmem_alloc(sizeof (itx_async_node_t
),
1937 list_create(&ian
->ia_list
, sizeof (itx_t
),
1938 offsetof(itx_t
, itx_node
));
1939 ian
->ia_foid
= foid
;
1940 avl_insert(t
, ian
, where
);
1942 list_insert_tail(&ian
->ia_list
, itx
);
1945 itx
->itx_lr
.lrc_txg
= dmu_tx_get_txg(tx
);
1948 * We don't want to dirty the ZIL using ZILTEST_TXG, because
1949 * zil_clean() will never be called using ZILTEST_TXG. Thus, we
1950 * need to be careful to always dirty the ZIL using the "real"
1951 * TXG (not itxg_txg) even when the SPA is frozen.
1953 zilog_dirty(zilog
, dmu_tx_get_txg(tx
));
1954 mutex_exit(&itxg
->itxg_lock
);
1956 /* Release the old itxs now we've dropped the lock */
1958 zil_itxg_clean(clean
);
1962 * If there are any in-memory intent log transactions which have now been
1963 * synced then start up a taskq to free them. We should only do this after we
1964 * have written out the uberblocks (i.e. txg has been comitted) so that
1965 * don't inadvertently clean out in-memory log records that would be required
1969 zil_clean(zilog_t
*zilog
, uint64_t synced_txg
)
1971 itxg_t
*itxg
= &zilog
->zl_itxg
[synced_txg
& TXG_MASK
];
1974 ASSERT3U(synced_txg
, <, ZILTEST_TXG
);
1976 mutex_enter(&itxg
->itxg_lock
);
1977 if (itxg
->itxg_itxs
== NULL
|| itxg
->itxg_txg
== ZILTEST_TXG
) {
1978 mutex_exit(&itxg
->itxg_lock
);
1981 ASSERT3U(itxg
->itxg_txg
, <=, synced_txg
);
1982 ASSERT3U(itxg
->itxg_txg
, !=, 0);
1983 clean_me
= itxg
->itxg_itxs
;
1984 itxg
->itxg_itxs
= NULL
;
1986 mutex_exit(&itxg
->itxg_lock
);
1988 * Preferably start a task queue to free up the old itxs but
1989 * if taskq_dispatch can't allocate resources to do that then
1990 * free it in-line. This should be rare. Note, using TQ_SLEEP
1991 * created a bad performance problem.
1993 ASSERT3P(zilog
->zl_dmu_pool
, !=, NULL
);
1994 ASSERT3P(zilog
->zl_dmu_pool
->dp_zil_clean_taskq
, !=, NULL
);
1995 taskqid_t id
= taskq_dispatch(zilog
->zl_dmu_pool
->dp_zil_clean_taskq
,
1996 (void (*)(void *))zil_itxg_clean
, clean_me
, TQ_NOSLEEP
);
1997 if (id
== TASKQID_INVALID
)
1998 zil_itxg_clean(clean_me
);
2002 * This function will traverse the queue of itxs that need to be
2003 * committed, and move them onto the ZIL's zl_itx_commit_list.
2006 zil_get_commit_list(zilog_t
*zilog
)
2009 list_t
*commit_list
= &zilog
->zl_itx_commit_list
;
2011 ASSERT(MUTEX_HELD(&zilog
->zl_issuer_lock
));
2013 if (spa_freeze_txg(zilog
->zl_spa
) != UINT64_MAX
) /* ziltest support */
2016 otxg
= spa_last_synced_txg(zilog
->zl_spa
) + 1;
2019 * This is inherently racy, since there is nothing to prevent
2020 * the last synced txg from changing. That's okay since we'll
2021 * only commit things in the future.
2023 for (txg
= otxg
; txg
< (otxg
+ TXG_CONCURRENT_STATES
); txg
++) {
2024 itxg_t
*itxg
= &zilog
->zl_itxg
[txg
& TXG_MASK
];
2026 mutex_enter(&itxg
->itxg_lock
);
2027 if (itxg
->itxg_txg
!= txg
) {
2028 mutex_exit(&itxg
->itxg_lock
);
2033 * If we're adding itx records to the zl_itx_commit_list,
2034 * then the zil better be dirty in this "txg". We can assert
2035 * that here since we're holding the itxg_lock which will
2036 * prevent spa_sync from cleaning it. Once we add the itxs
2037 * to the zl_itx_commit_list we must commit it to disk even
2038 * if it's unnecessary (i.e. the txg was synced).
2040 ASSERT(zilog_is_dirty_in_txg(zilog
, txg
) ||
2041 spa_freeze_txg(zilog
->zl_spa
) != UINT64_MAX
);
2042 list_move_tail(commit_list
, &itxg
->itxg_itxs
->i_sync_list
);
2044 mutex_exit(&itxg
->itxg_lock
);
2049 * Move the async itxs for a specified object to commit into sync lists.
2052 zil_async_to_sync(zilog_t
*zilog
, uint64_t foid
)
2055 itx_async_node_t
*ian
;
2059 if (spa_freeze_txg(zilog
->zl_spa
) != UINT64_MAX
) /* ziltest support */
2062 otxg
= spa_last_synced_txg(zilog
->zl_spa
) + 1;
2065 * This is inherently racy, since there is nothing to prevent
2066 * the last synced txg from changing.
2068 for (txg
= otxg
; txg
< (otxg
+ TXG_CONCURRENT_STATES
); txg
++) {
2069 itxg_t
*itxg
= &zilog
->zl_itxg
[txg
& TXG_MASK
];
2071 mutex_enter(&itxg
->itxg_lock
);
2072 if (itxg
->itxg_txg
!= txg
) {
2073 mutex_exit(&itxg
->itxg_lock
);
2078 * If a foid is specified then find that node and append its
2079 * list. Otherwise walk the tree appending all the lists
2080 * to the sync list. We add to the end rather than the
2081 * beginning to ensure the create has happened.
2083 t
= &itxg
->itxg_itxs
->i_async_tree
;
2085 ian
= avl_find(t
, &foid
, &where
);
2087 list_move_tail(&itxg
->itxg_itxs
->i_sync_list
,
2091 void *cookie
= NULL
;
2093 while ((ian
= avl_destroy_nodes(t
, &cookie
)) != NULL
) {
2094 list_move_tail(&itxg
->itxg_itxs
->i_sync_list
,
2096 list_destroy(&ian
->ia_list
);
2097 kmem_free(ian
, sizeof (itx_async_node_t
));
2100 mutex_exit(&itxg
->itxg_lock
);
2105 * This function will prune commit itxs that are at the head of the
2106 * commit list (it won't prune past the first non-commit itx), and
2107 * either: a) attach them to the last lwb that's still pending
2108 * completion, or b) skip them altogether.
2110 * This is used as a performance optimization to prevent commit itxs
2111 * from generating new lwbs when it's unnecessary to do so.
2114 zil_prune_commit_list(zilog_t
*zilog
)
2118 ASSERT(MUTEX_HELD(&zilog
->zl_issuer_lock
));
2120 while ((itx
= list_head(&zilog
->zl_itx_commit_list
)) != NULL
) {
2121 lr_t
*lrc
= &itx
->itx_lr
;
2122 if (lrc
->lrc_txtype
!= TX_COMMIT
)
2125 mutex_enter(&zilog
->zl_lock
);
2127 lwb_t
*last_lwb
= zilog
->zl_last_lwb_opened
;
2128 if (last_lwb
== NULL
||
2129 last_lwb
->lwb_state
== LWB_STATE_FLUSH_DONE
) {
2131 * All of the itxs this waiter was waiting on
2132 * must have already completed (or there were
2133 * never any itx's for it to wait on), so it's
2134 * safe to skip this waiter and mark it done.
2136 zil_commit_waiter_skip(itx
->itx_private
);
2138 zil_commit_waiter_link_lwb(itx
->itx_private
, last_lwb
);
2139 itx
->itx_private
= NULL
;
2142 mutex_exit(&zilog
->zl_lock
);
2144 list_remove(&zilog
->zl_itx_commit_list
, itx
);
2145 zil_itx_destroy(itx
);
2148 IMPLY(itx
!= NULL
, itx
->itx_lr
.lrc_txtype
!= TX_COMMIT
);
2152 zil_commit_writer_stall(zilog_t
*zilog
)
2155 * When zio_alloc_zil() fails to allocate the next lwb block on
2156 * disk, we must call txg_wait_synced() to ensure all of the
2157 * lwbs in the zilog's zl_lwb_list are synced and then freed (in
2158 * zil_sync()), such that any subsequent ZIL writer (i.e. a call
2159 * to zil_process_commit_list()) will have to call zil_create(),
2160 * and start a new ZIL chain.
2162 * Since zil_alloc_zil() failed, the lwb that was previously
2163 * issued does not have a pointer to the "next" lwb on disk.
2164 * Thus, if another ZIL writer thread was to allocate the "next"
2165 * on-disk lwb, that block could be leaked in the event of a
2166 * crash (because the previous lwb on-disk would not point to
2169 * We must hold the zilog's zl_issuer_lock while we do this, to
2170 * ensure no new threads enter zil_process_commit_list() until
2171 * all lwb's in the zl_lwb_list have been synced and freed
2172 * (which is achieved via the txg_wait_synced() call).
2174 ASSERT(MUTEX_HELD(&zilog
->zl_issuer_lock
));
2175 txg_wait_synced(zilog
->zl_dmu_pool
, 0);
2176 ASSERT3P(list_tail(&zilog
->zl_lwb_list
), ==, NULL
);
2180 * This function will traverse the commit list, creating new lwbs as
2181 * needed, and committing the itxs from the commit list to these newly
2182 * created lwbs. Additionally, as a new lwb is created, the previous
2183 * lwb will be issued to the zio layer to be written to disk.
2186 zil_process_commit_list(zilog_t
*zilog
)
2188 spa_t
*spa
= zilog
->zl_spa
;
2190 list_t nolwb_waiters
;
2194 ASSERT(MUTEX_HELD(&zilog
->zl_issuer_lock
));
2197 * Return if there's nothing to commit before we dirty the fs by
2198 * calling zil_create().
2200 if (list_head(&zilog
->zl_itx_commit_list
) == NULL
)
2203 list_create(&nolwb_itxs
, sizeof (itx_t
), offsetof(itx_t
, itx_node
));
2204 list_create(&nolwb_waiters
, sizeof (zil_commit_waiter_t
),
2205 offsetof(zil_commit_waiter_t
, zcw_node
));
2207 lwb
= list_tail(&zilog
->zl_lwb_list
);
2209 lwb
= zil_create(zilog
);
2211 ASSERT3S(lwb
->lwb_state
, !=, LWB_STATE_ISSUED
);
2212 ASSERT3S(lwb
->lwb_state
, !=, LWB_STATE_WRITE_DONE
);
2213 ASSERT3S(lwb
->lwb_state
, !=, LWB_STATE_FLUSH_DONE
);
2216 while ((itx
= list_head(&zilog
->zl_itx_commit_list
)) != NULL
) {
2217 lr_t
*lrc
= &itx
->itx_lr
;
2218 uint64_t txg
= lrc
->lrc_txg
;
2220 ASSERT3U(txg
, !=, 0);
2222 if (lrc
->lrc_txtype
== TX_COMMIT
) {
2223 DTRACE_PROBE2(zil__process__commit__itx
,
2224 zilog_t
*, zilog
, itx_t
*, itx
);
2226 DTRACE_PROBE2(zil__process__normal__itx
,
2227 zilog_t
*, zilog
, itx_t
*, itx
);
2230 list_remove(&zilog
->zl_itx_commit_list
, itx
);
2232 boolean_t synced
= txg
<= spa_last_synced_txg(spa
);
2233 boolean_t frozen
= txg
> spa_freeze_txg(spa
);
2236 * If the txg of this itx has already been synced out, then
2237 * we don't need to commit this itx to an lwb. This is
2238 * because the data of this itx will have already been
2239 * written to the main pool. This is inherently racy, and
2240 * it's still ok to commit an itx whose txg has already
2241 * been synced; this will result in a write that's
2242 * unnecessary, but will do no harm.
2244 * With that said, we always want to commit TX_COMMIT itxs
2245 * to an lwb, regardless of whether or not that itx's txg
2246 * has been synced out. We do this to ensure any OPENED lwb
2247 * will always have at least one zil_commit_waiter_t linked
2250 * As a counter-example, if we skipped TX_COMMIT itx's
2251 * whose txg had already been synced, the following
2252 * situation could occur if we happened to be racing with
2255 * 1. We commit a non-TX_COMMIT itx to an lwb, where the
2256 * itx's txg is 10 and the last synced txg is 9.
2257 * 2. spa_sync finishes syncing out txg 10.
2258 * 3. We move to the next itx in the list, it's a TX_COMMIT
2259 * whose txg is 10, so we skip it rather than committing
2260 * it to the lwb used in (1).
2262 * If the itx that is skipped in (3) is the last TX_COMMIT
2263 * itx in the commit list, than it's possible for the lwb
2264 * used in (1) to remain in the OPENED state indefinitely.
2266 * To prevent the above scenario from occurring, ensuring
2267 * that once an lwb is OPENED it will transition to ISSUED
2268 * and eventually DONE, we always commit TX_COMMIT itx's to
2269 * an lwb here, even if that itx's txg has already been
2272 * Finally, if the pool is frozen, we _always_ commit the
2273 * itx. The point of freezing the pool is to prevent data
2274 * from being written to the main pool via spa_sync, and
2275 * instead rely solely on the ZIL to persistently store the
2276 * data; i.e. when the pool is frozen, the last synced txg
2277 * value can't be trusted.
2279 if (frozen
|| !synced
|| lrc
->lrc_txtype
== TX_COMMIT
) {
2281 lwb
= zil_lwb_commit(zilog
, itx
, lwb
);
2284 list_insert_tail(&nolwb_itxs
, itx
);
2286 list_insert_tail(&lwb
->lwb_itxs
, itx
);
2288 if (lrc
->lrc_txtype
== TX_COMMIT
) {
2289 zil_commit_waiter_link_nolwb(
2290 itx
->itx_private
, &nolwb_waiters
);
2293 list_insert_tail(&nolwb_itxs
, itx
);
2296 ASSERT3S(lrc
->lrc_txtype
, !=, TX_COMMIT
);
2297 zil_itx_destroy(itx
);
2303 * This indicates zio_alloc_zil() failed to allocate the
2304 * "next" lwb on-disk. When this happens, we must stall
2305 * the ZIL write pipeline; see the comment within
2306 * zil_commit_writer_stall() for more details.
2308 zil_commit_writer_stall(zilog
);
2311 * Additionally, we have to signal and mark the "nolwb"
2312 * waiters as "done" here, since without an lwb, we
2313 * can't do this via zil_lwb_flush_vdevs_done() like
2316 zil_commit_waiter_t
*zcw
;
2317 while ((zcw
= list_head(&nolwb_waiters
)) != NULL
) {
2318 zil_commit_waiter_skip(zcw
);
2319 list_remove(&nolwb_waiters
, zcw
);
2323 * And finally, we have to destroy the itx's that
2324 * couldn't be committed to an lwb; this will also call
2325 * the itx's callback if one exists for the itx.
2327 while ((itx
= list_head(&nolwb_itxs
)) != NULL
) {
2328 list_remove(&nolwb_itxs
, itx
);
2329 zil_itx_destroy(itx
);
2332 ASSERT(list_is_empty(&nolwb_waiters
));
2333 ASSERT3P(lwb
, !=, NULL
);
2334 ASSERT3S(lwb
->lwb_state
, !=, LWB_STATE_ISSUED
);
2335 ASSERT3S(lwb
->lwb_state
, !=, LWB_STATE_WRITE_DONE
);
2336 ASSERT3S(lwb
->lwb_state
, !=, LWB_STATE_FLUSH_DONE
);
2339 * At this point, the ZIL block pointed at by the "lwb"
2340 * variable is in one of the following states: "closed"
2343 * If it's "closed", then no itxs have been committed to
2344 * it, so there's no point in issuing its zio (i.e. it's
2347 * If it's "open", then it contains one or more itxs that
2348 * eventually need to be committed to stable storage. In
2349 * this case we intentionally do not issue the lwb's zio
2350 * to disk yet, and instead rely on one of the following
2351 * two mechanisms for issuing the zio:
2353 * 1. Ideally, there will be more ZIL activity occurring
2354 * on the system, such that this function will be
2355 * immediately called again (not necessarily by the same
2356 * thread) and this lwb's zio will be issued via
2357 * zil_lwb_commit(). This way, the lwb is guaranteed to
2358 * be "full" when it is issued to disk, and we'll make
2359 * use of the lwb's size the best we can.
2361 * 2. If there isn't sufficient ZIL activity occurring on
2362 * the system, such that this lwb's zio isn't issued via
2363 * zil_lwb_commit(), zil_commit_waiter() will issue the
2364 * lwb's zio. If this occurs, the lwb is not guaranteed
2365 * to be "full" by the time its zio is issued, and means
2366 * the size of the lwb was "too large" given the amount
2367 * of ZIL activity occurring on the system at that time.
2369 * We do this for a couple of reasons:
2371 * 1. To try and reduce the number of IOPs needed to
2372 * write the same number of itxs. If an lwb has space
2373 * available in its buffer for more itxs, and more itxs
2374 * will be committed relatively soon (relative to the
2375 * latency of performing a write), then it's beneficial
2376 * to wait for these "next" itxs. This way, more itxs
2377 * can be committed to stable storage with fewer writes.
2379 * 2. To try and use the largest lwb block size that the
2380 * incoming rate of itxs can support. Again, this is to
2381 * try and pack as many itxs into as few lwbs as
2382 * possible, without significantly impacting the latency
2383 * of each individual itx.
2389 * This function is responsible for ensuring the passed in commit waiter
2390 * (and associated commit itx) is committed to an lwb. If the waiter is
2391 * not already committed to an lwb, all itxs in the zilog's queue of
2392 * itxs will be processed. The assumption is the passed in waiter's
2393 * commit itx will found in the queue just like the other non-commit
2394 * itxs, such that when the entire queue is processed, the waiter will
2395 * have been committed to an lwb.
2397 * The lwb associated with the passed in waiter is not guaranteed to
2398 * have been issued by the time this function completes. If the lwb is
2399 * not issued, we rely on future calls to zil_commit_writer() to issue
2400 * the lwb, or the timeout mechanism found in zil_commit_waiter().
2403 zil_commit_writer(zilog_t
*zilog
, zil_commit_waiter_t
*zcw
)
2405 ASSERT(!MUTEX_HELD(&zilog
->zl_lock
));
2406 ASSERT(spa_writeable(zilog
->zl_spa
));
2408 mutex_enter(&zilog
->zl_issuer_lock
);
2410 if (zcw
->zcw_lwb
!= NULL
|| zcw
->zcw_done
) {
2412 * It's possible that, while we were waiting to acquire
2413 * the "zl_issuer_lock", another thread committed this
2414 * waiter to an lwb. If that occurs, we bail out early,
2415 * without processing any of the zilog's queue of itxs.
2417 * On certain workloads and system configurations, the
2418 * "zl_issuer_lock" can become highly contended. In an
2419 * attempt to reduce this contention, we immediately drop
2420 * the lock if the waiter has already been processed.
2422 * We've measured this optimization to reduce CPU spent
2423 * contending on this lock by up to 5%, using a system
2424 * with 32 CPUs, low latency storage (~50 usec writes),
2425 * and 1024 threads performing sync writes.
2430 ZIL_STAT_BUMP(zil_commit_writer_count
);
2432 zil_get_commit_list(zilog
);
2433 zil_prune_commit_list(zilog
);
2434 zil_process_commit_list(zilog
);
2437 mutex_exit(&zilog
->zl_issuer_lock
);
2441 zil_commit_waiter_timeout(zilog_t
*zilog
, zil_commit_waiter_t
*zcw
)
2443 ASSERT(!MUTEX_HELD(&zilog
->zl_issuer_lock
));
2444 ASSERT(MUTEX_HELD(&zcw
->zcw_lock
));
2445 ASSERT3B(zcw
->zcw_done
, ==, B_FALSE
);
2447 lwb_t
*lwb
= zcw
->zcw_lwb
;
2448 ASSERT3P(lwb
, !=, NULL
);
2449 ASSERT3S(lwb
->lwb_state
, !=, LWB_STATE_CLOSED
);
2452 * If the lwb has already been issued by another thread, we can
2453 * immediately return since there's no work to be done (the
2454 * point of this function is to issue the lwb). Additionally, we
2455 * do this prior to acquiring the zl_issuer_lock, to avoid
2456 * acquiring it when it's not necessary to do so.
2458 if (lwb
->lwb_state
== LWB_STATE_ISSUED
||
2459 lwb
->lwb_state
== LWB_STATE_WRITE_DONE
||
2460 lwb
->lwb_state
== LWB_STATE_FLUSH_DONE
)
2464 * In order to call zil_lwb_write_issue() we must hold the
2465 * zilog's "zl_issuer_lock". We can't simply acquire that lock,
2466 * since we're already holding the commit waiter's "zcw_lock",
2467 * and those two locks are acquired in the opposite order
2470 mutex_exit(&zcw
->zcw_lock
);
2471 mutex_enter(&zilog
->zl_issuer_lock
);
2472 mutex_enter(&zcw
->zcw_lock
);
2475 * Since we just dropped and re-acquired the commit waiter's
2476 * lock, we have to re-check to see if the waiter was marked
2477 * "done" during that process. If the waiter was marked "done",
2478 * the "lwb" pointer is no longer valid (it can be free'd after
2479 * the waiter is marked "done"), so without this check we could
2480 * wind up with a use-after-free error below.
2485 ASSERT3P(lwb
, ==, zcw
->zcw_lwb
);
2488 * We've already checked this above, but since we hadn't acquired
2489 * the zilog's zl_issuer_lock, we have to perform this check a
2490 * second time while holding the lock.
2492 * We don't need to hold the zl_lock since the lwb cannot transition
2493 * from OPENED to ISSUED while we hold the zl_issuer_lock. The lwb
2494 * _can_ transition from ISSUED to DONE, but it's OK to race with
2495 * that transition since we treat the lwb the same, whether it's in
2496 * the ISSUED or DONE states.
2498 * The important thing, is we treat the lwb differently depending on
2499 * if it's ISSUED or OPENED, and block any other threads that might
2500 * attempt to issue this lwb. For that reason we hold the
2501 * zl_issuer_lock when checking the lwb_state; we must not call
2502 * zil_lwb_write_issue() if the lwb had already been issued.
2504 * See the comment above the lwb_state_t structure definition for
2505 * more details on the lwb states, and locking requirements.
2507 if (lwb
->lwb_state
== LWB_STATE_ISSUED
||
2508 lwb
->lwb_state
== LWB_STATE_WRITE_DONE
||
2509 lwb
->lwb_state
== LWB_STATE_FLUSH_DONE
)
2512 ASSERT3S(lwb
->lwb_state
, ==, LWB_STATE_OPENED
);
2515 * As described in the comments above zil_commit_waiter() and
2516 * zil_process_commit_list(), we need to issue this lwb's zio
2517 * since we've reached the commit waiter's timeout and it still
2518 * hasn't been issued.
2520 lwb_t
*nlwb
= zil_lwb_write_issue(zilog
, lwb
);
2522 IMPLY(nlwb
!= NULL
, lwb
->lwb_state
!= LWB_STATE_OPENED
);
2525 * Since the lwb's zio hadn't been issued by the time this thread
2526 * reached its timeout, we reset the zilog's "zl_cur_used" field
2527 * to influence the zil block size selection algorithm.
2529 * By having to issue the lwb's zio here, it means the size of the
2530 * lwb was too large, given the incoming throughput of itxs. By
2531 * setting "zl_cur_used" to zero, we communicate this fact to the
2532 * block size selection algorithm, so it can take this information
2533 * into account, and potentially select a smaller size for the
2534 * next lwb block that is allocated.
2536 zilog
->zl_cur_used
= 0;
2540 * When zil_lwb_write_issue() returns NULL, this
2541 * indicates zio_alloc_zil() failed to allocate the
2542 * "next" lwb on-disk. When this occurs, the ZIL write
2543 * pipeline must be stalled; see the comment within the
2544 * zil_commit_writer_stall() function for more details.
2546 * We must drop the commit waiter's lock prior to
2547 * calling zil_commit_writer_stall() or else we can wind
2548 * up with the following deadlock:
2550 * - This thread is waiting for the txg to sync while
2551 * holding the waiter's lock; txg_wait_synced() is
2552 * used within txg_commit_writer_stall().
2554 * - The txg can't sync because it is waiting for this
2555 * lwb's zio callback to call dmu_tx_commit().
2557 * - The lwb's zio callback can't call dmu_tx_commit()
2558 * because it's blocked trying to acquire the waiter's
2559 * lock, which occurs prior to calling dmu_tx_commit()
2561 mutex_exit(&zcw
->zcw_lock
);
2562 zil_commit_writer_stall(zilog
);
2563 mutex_enter(&zcw
->zcw_lock
);
2567 mutex_exit(&zilog
->zl_issuer_lock
);
2568 ASSERT(MUTEX_HELD(&zcw
->zcw_lock
));
2572 * This function is responsible for performing the following two tasks:
2574 * 1. its primary responsibility is to block until the given "commit
2575 * waiter" is considered "done".
2577 * 2. its secondary responsibility is to issue the zio for the lwb that
2578 * the given "commit waiter" is waiting on, if this function has
2579 * waited "long enough" and the lwb is still in the "open" state.
2581 * Given a sufficient amount of itxs being generated and written using
2582 * the ZIL, the lwb's zio will be issued via the zil_lwb_commit()
2583 * function. If this does not occur, this secondary responsibility will
2584 * ensure the lwb is issued even if there is not other synchronous
2585 * activity on the system.
2587 * For more details, see zil_process_commit_list(); more specifically,
2588 * the comment at the bottom of that function.
2591 zil_commit_waiter(zilog_t
*zilog
, zil_commit_waiter_t
*zcw
)
2593 ASSERT(!MUTEX_HELD(&zilog
->zl_lock
));
2594 ASSERT(!MUTEX_HELD(&zilog
->zl_issuer_lock
));
2595 ASSERT(spa_writeable(zilog
->zl_spa
));
2597 mutex_enter(&zcw
->zcw_lock
);
2600 * The timeout is scaled based on the lwb latency to avoid
2601 * significantly impacting the latency of each individual itx.
2602 * For more details, see the comment at the bottom of the
2603 * zil_process_commit_list() function.
2605 int pct
= MAX(zfs_commit_timeout_pct
, 1);
2606 hrtime_t sleep
= (zilog
->zl_last_lwb_latency
* pct
) / 100;
2607 hrtime_t wakeup
= gethrtime() + sleep
;
2608 boolean_t timedout
= B_FALSE
;
2610 while (!zcw
->zcw_done
) {
2611 ASSERT(MUTEX_HELD(&zcw
->zcw_lock
));
2613 lwb_t
*lwb
= zcw
->zcw_lwb
;
2616 * Usually, the waiter will have a non-NULL lwb field here,
2617 * but it's possible for it to be NULL as a result of
2618 * zil_commit() racing with spa_sync().
2620 * When zil_clean() is called, it's possible for the itxg
2621 * list (which may be cleaned via a taskq) to contain
2622 * commit itxs. When this occurs, the commit waiters linked
2623 * off of these commit itxs will not be committed to an
2624 * lwb. Additionally, these commit waiters will not be
2625 * marked done until zil_commit_waiter_skip() is called via
2628 * Thus, it's possible for this commit waiter (i.e. the
2629 * "zcw" variable) to be found in this "in between" state;
2630 * where it's "zcw_lwb" field is NULL, and it hasn't yet
2631 * been skipped, so it's "zcw_done" field is still B_FALSE.
2633 IMPLY(lwb
!= NULL
, lwb
->lwb_state
!= LWB_STATE_CLOSED
);
2635 if (lwb
!= NULL
&& lwb
->lwb_state
== LWB_STATE_OPENED
) {
2636 ASSERT3B(timedout
, ==, B_FALSE
);
2639 * If the lwb hasn't been issued yet, then we
2640 * need to wait with a timeout, in case this
2641 * function needs to issue the lwb after the
2642 * timeout is reached; responsibility (2) from
2643 * the comment above this function.
2645 clock_t timeleft
= cv_timedwait_hires(&zcw
->zcw_cv
,
2646 &zcw
->zcw_lock
, wakeup
, USEC2NSEC(1),
2647 CALLOUT_FLAG_ABSOLUTE
);
2649 if (timeleft
>= 0 || zcw
->zcw_done
)
2653 zil_commit_waiter_timeout(zilog
, zcw
);
2655 if (!zcw
->zcw_done
) {
2657 * If the commit waiter has already been
2658 * marked "done", it's possible for the
2659 * waiter's lwb structure to have already
2660 * been freed. Thus, we can only reliably
2661 * make these assertions if the waiter
2664 ASSERT3P(lwb
, ==, zcw
->zcw_lwb
);
2665 ASSERT3S(lwb
->lwb_state
, !=, LWB_STATE_OPENED
);
2669 * If the lwb isn't open, then it must have already
2670 * been issued. In that case, there's no need to
2671 * use a timeout when waiting for the lwb to
2674 * Additionally, if the lwb is NULL, the waiter
2675 * will soon be signaled and marked done via
2676 * zil_clean() and zil_itxg_clean(), so no timeout
2681 lwb
->lwb_state
== LWB_STATE_ISSUED
||
2682 lwb
->lwb_state
== LWB_STATE_WRITE_DONE
||
2683 lwb
->lwb_state
== LWB_STATE_FLUSH_DONE
);
2684 cv_wait(&zcw
->zcw_cv
, &zcw
->zcw_lock
);
2688 mutex_exit(&zcw
->zcw_lock
);
2691 static zil_commit_waiter_t
*
2692 zil_alloc_commit_waiter(void)
2694 zil_commit_waiter_t
*zcw
= kmem_cache_alloc(zil_zcw_cache
, KM_SLEEP
);
2696 cv_init(&zcw
->zcw_cv
, NULL
, CV_DEFAULT
, NULL
);
2697 mutex_init(&zcw
->zcw_lock
, NULL
, MUTEX_DEFAULT
, NULL
);
2698 list_link_init(&zcw
->zcw_node
);
2699 zcw
->zcw_lwb
= NULL
;
2700 zcw
->zcw_done
= B_FALSE
;
2701 zcw
->zcw_zio_error
= 0;
2707 zil_free_commit_waiter(zil_commit_waiter_t
*zcw
)
2709 ASSERT(!list_link_active(&zcw
->zcw_node
));
2710 ASSERT3P(zcw
->zcw_lwb
, ==, NULL
);
2711 ASSERT3B(zcw
->zcw_done
, ==, B_TRUE
);
2712 mutex_destroy(&zcw
->zcw_lock
);
2713 cv_destroy(&zcw
->zcw_cv
);
2714 kmem_cache_free(zil_zcw_cache
, zcw
);
2718 * This function is used to create a TX_COMMIT itx and assign it. This
2719 * way, it will be linked into the ZIL's list of synchronous itxs, and
2720 * then later committed to an lwb (or skipped) when
2721 * zil_process_commit_list() is called.
2724 zil_commit_itx_assign(zilog_t
*zilog
, zil_commit_waiter_t
*zcw
)
2726 dmu_tx_t
*tx
= dmu_tx_create(zilog
->zl_os
);
2727 VERIFY0(dmu_tx_assign(tx
, TXG_WAIT
));
2729 itx_t
*itx
= zil_itx_create(TX_COMMIT
, sizeof (lr_t
));
2730 itx
->itx_sync
= B_TRUE
;
2731 itx
->itx_private
= zcw
;
2733 zil_itx_assign(zilog
, itx
, tx
);
2739 * Commit ZFS Intent Log transactions (itxs) to stable storage.
2741 * When writing ZIL transactions to the on-disk representation of the
2742 * ZIL, the itxs are committed to a Log Write Block (lwb). Multiple
2743 * itxs can be committed to a single lwb. Once a lwb is written and
2744 * committed to stable storage (i.e. the lwb is written, and vdevs have
2745 * been flushed), each itx that was committed to that lwb is also
2746 * considered to be committed to stable storage.
2748 * When an itx is committed to an lwb, the log record (lr_t) contained
2749 * by the itx is copied into the lwb's zio buffer, and once this buffer
2750 * is written to disk, it becomes an on-disk ZIL block.
2752 * As itxs are generated, they're inserted into the ZIL's queue of
2753 * uncommitted itxs. The semantics of zil_commit() are such that it will
2754 * block until all itxs that were in the queue when it was called, are
2755 * committed to stable storage.
2757 * If "foid" is zero, this means all "synchronous" and "asynchronous"
2758 * itxs, for all objects in the dataset, will be committed to stable
2759 * storage prior to zil_commit() returning. If "foid" is non-zero, all
2760 * "synchronous" itxs for all objects, but only "asynchronous" itxs
2761 * that correspond to the foid passed in, will be committed to stable
2762 * storage prior to zil_commit() returning.
2764 * Generally speaking, when zil_commit() is called, the consumer doesn't
2765 * actually care about _all_ of the uncommitted itxs. Instead, they're
2766 * simply trying to waiting for a specific itx to be committed to disk,
2767 * but the interface(s) for interacting with the ZIL don't allow such
2768 * fine-grained communication. A better interface would allow a consumer
2769 * to create and assign an itx, and then pass a reference to this itx to
2770 * zil_commit(); such that zil_commit() would return as soon as that
2771 * specific itx was committed to disk (instead of waiting for _all_
2772 * itxs to be committed).
2774 * When a thread calls zil_commit() a special "commit itx" will be
2775 * generated, along with a corresponding "waiter" for this commit itx.
2776 * zil_commit() will wait on this waiter's CV, such that when the waiter
2777 * is marked done, and signaled, zil_commit() will return.
2779 * This commit itx is inserted into the queue of uncommitted itxs. This
2780 * provides an easy mechanism for determining which itxs were in the
2781 * queue prior to zil_commit() having been called, and which itxs were
2782 * added after zil_commit() was called.
2784 * The commit it is special; it doesn't have any on-disk representation.
2785 * When a commit itx is "committed" to an lwb, the waiter associated
2786 * with it is linked onto the lwb's list of waiters. Then, when that lwb
2787 * completes, each waiter on the lwb's list is marked done and signaled
2788 * -- allowing the thread waiting on the waiter to return from zil_commit().
2790 * It's important to point out a few critical factors that allow us
2791 * to make use of the commit itxs, commit waiters, per-lwb lists of
2792 * commit waiters, and zio completion callbacks like we're doing:
2794 * 1. The list of waiters for each lwb is traversed, and each commit
2795 * waiter is marked "done" and signaled, in the zio completion
2796 * callback of the lwb's zio[*].
2798 * * Actually, the waiters are signaled in the zio completion
2799 * callback of the root zio for the DKIOCFLUSHWRITECACHE commands
2800 * that are sent to the vdevs upon completion of the lwb zio.
2802 * 2. When the itxs are inserted into the ZIL's queue of uncommitted
2803 * itxs, the order in which they are inserted is preserved[*]; as
2804 * itxs are added to the queue, they are added to the tail of
2805 * in-memory linked lists.
2807 * When committing the itxs to lwbs (to be written to disk), they
2808 * are committed in the same order in which the itxs were added to
2809 * the uncommitted queue's linked list(s); i.e. the linked list of
2810 * itxs to commit is traversed from head to tail, and each itx is
2811 * committed to an lwb in that order.
2815 * - the order of "sync" itxs is preserved w.r.t. other
2816 * "sync" itxs, regardless of the corresponding objects.
2817 * - the order of "async" itxs is preserved w.r.t. other
2818 * "async" itxs corresponding to the same object.
2819 * - the order of "async" itxs is *not* preserved w.r.t. other
2820 * "async" itxs corresponding to different objects.
2821 * - the order of "sync" itxs w.r.t. "async" itxs (or vice
2822 * versa) is *not* preserved, even for itxs that correspond
2823 * to the same object.
2825 * For more details, see: zil_itx_assign(), zil_async_to_sync(),
2826 * zil_get_commit_list(), and zil_process_commit_list().
2828 * 3. The lwbs represent a linked list of blocks on disk. Thus, any
2829 * lwb cannot be considered committed to stable storage, until its
2830 * "previous" lwb is also committed to stable storage. This fact,
2831 * coupled with the fact described above, means that itxs are
2832 * committed in (roughly) the order in which they were generated.
2833 * This is essential because itxs are dependent on prior itxs.
2834 * Thus, we *must not* deem an itx as being committed to stable
2835 * storage, until *all* prior itxs have also been committed to
2838 * To enforce this ordering of lwb zio's, while still leveraging as
2839 * much of the underlying storage performance as possible, we rely
2840 * on two fundamental concepts:
2842 * 1. The creation and issuance of lwb zio's is protected by
2843 * the zilog's "zl_issuer_lock", which ensures only a single
2844 * thread is creating and/or issuing lwb's at a time
2845 * 2. The "previous" lwb is a child of the "current" lwb
2846 * (leveraging the zio parent-child dependency graph)
2848 * By relying on this parent-child zio relationship, we can have
2849 * many lwb zio's concurrently issued to the underlying storage,
2850 * but the order in which they complete will be the same order in
2851 * which they were created.
2854 zil_commit(zilog_t
*zilog
, uint64_t foid
)
2857 * We should never attempt to call zil_commit on a snapshot for
2858 * a couple of reasons:
2860 * 1. A snapshot may never be modified, thus it cannot have any
2861 * in-flight itxs that would have modified the dataset.
2863 * 2. By design, when zil_commit() is called, a commit itx will
2864 * be assigned to this zilog; as a result, the zilog will be
2865 * dirtied. We must not dirty the zilog of a snapshot; there's
2866 * checks in the code that enforce this invariant, and will
2867 * cause a panic if it's not upheld.
2869 ASSERT3B(dmu_objset_is_snapshot(zilog
->zl_os
), ==, B_FALSE
);
2871 if (zilog
->zl_sync
== ZFS_SYNC_DISABLED
)
2874 if (!spa_writeable(zilog
->zl_spa
)) {
2876 * If the SPA is not writable, there should never be any
2877 * pending itxs waiting to be committed to disk. If that
2878 * weren't true, we'd skip writing those itxs out, and
2879 * would break the semantics of zil_commit(); thus, we're
2880 * verifying that truth before we return to the caller.
2882 ASSERT(list_is_empty(&zilog
->zl_lwb_list
));
2883 ASSERT3P(zilog
->zl_last_lwb_opened
, ==, NULL
);
2884 for (int i
= 0; i
< TXG_SIZE
; i
++)
2885 ASSERT3P(zilog
->zl_itxg
[i
].itxg_itxs
, ==, NULL
);
2890 * If the ZIL is suspended, we don't want to dirty it by calling
2891 * zil_commit_itx_assign() below, nor can we write out
2892 * lwbs like would be done in zil_commit_write(). Thus, we
2893 * simply rely on txg_wait_synced() to maintain the necessary
2894 * semantics, and avoid calling those functions altogether.
2896 if (zilog
->zl_suspend
> 0) {
2897 txg_wait_synced(zilog
->zl_dmu_pool
, 0);
2901 zil_commit_impl(zilog
, foid
);
2905 zil_commit_impl(zilog_t
*zilog
, uint64_t foid
)
2907 ZIL_STAT_BUMP(zil_commit_count
);
2910 * Move the "async" itxs for the specified foid to the "sync"
2911 * queues, such that they will be later committed (or skipped)
2912 * to an lwb when zil_process_commit_list() is called.
2914 * Since these "async" itxs must be committed prior to this
2915 * call to zil_commit returning, we must perform this operation
2916 * before we call zil_commit_itx_assign().
2918 zil_async_to_sync(zilog
, foid
);
2921 * We allocate a new "waiter" structure which will initially be
2922 * linked to the commit itx using the itx's "itx_private" field.
2923 * Since the commit itx doesn't represent any on-disk state,
2924 * when it's committed to an lwb, rather than copying the its
2925 * lr_t into the lwb's buffer, the commit itx's "waiter" will be
2926 * added to the lwb's list of waiters. Then, when the lwb is
2927 * committed to stable storage, each waiter in the lwb's list of
2928 * waiters will be marked "done", and signalled.
2930 * We must create the waiter and assign the commit itx prior to
2931 * calling zil_commit_writer(), or else our specific commit itx
2932 * is not guaranteed to be committed to an lwb prior to calling
2933 * zil_commit_waiter().
2935 zil_commit_waiter_t
*zcw
= zil_alloc_commit_waiter();
2936 zil_commit_itx_assign(zilog
, zcw
);
2938 zil_commit_writer(zilog
, zcw
);
2939 zil_commit_waiter(zilog
, zcw
);
2941 if (zcw
->zcw_zio_error
!= 0) {
2943 * If there was an error writing out the ZIL blocks that
2944 * this thread is waiting on, then we fallback to
2945 * relying on spa_sync() to write out the data this
2946 * thread is waiting on. Obviously this has performance
2947 * implications, but the expectation is for this to be
2948 * an exceptional case, and shouldn't occur often.
2950 DTRACE_PROBE2(zil__commit__io__error
,
2951 zilog_t
*, zilog
, zil_commit_waiter_t
*, zcw
);
2952 txg_wait_synced(zilog
->zl_dmu_pool
, 0);
2955 zil_free_commit_waiter(zcw
);
2959 * Called in syncing context to free committed log blocks and update log header.
2962 zil_sync(zilog_t
*zilog
, dmu_tx_t
*tx
)
2964 zil_header_t
*zh
= zil_header_in_syncing_context(zilog
);
2965 uint64_t txg
= dmu_tx_get_txg(tx
);
2966 spa_t
*spa
= zilog
->zl_spa
;
2967 uint64_t *replayed_seq
= &zilog
->zl_replayed_seq
[txg
& TXG_MASK
];
2971 * We don't zero out zl_destroy_txg, so make sure we don't try
2972 * to destroy it twice.
2974 if (spa_sync_pass(spa
) != 1)
2977 mutex_enter(&zilog
->zl_lock
);
2979 ASSERT(zilog
->zl_stop_sync
== 0);
2981 if (*replayed_seq
!= 0) {
2982 ASSERT(zh
->zh_replay_seq
< *replayed_seq
);
2983 zh
->zh_replay_seq
= *replayed_seq
;
2987 if (zilog
->zl_destroy_txg
== txg
) {
2988 blkptr_t blk
= zh
->zh_log
;
2990 ASSERT(list_head(&zilog
->zl_lwb_list
) == NULL
);
2992 bzero(zh
, sizeof (zil_header_t
));
2993 bzero(zilog
->zl_replayed_seq
, sizeof (zilog
->zl_replayed_seq
));
2995 if (zilog
->zl_keep_first
) {
2997 * If this block was part of log chain that couldn't
2998 * be claimed because a device was missing during
2999 * zil_claim(), but that device later returns,
3000 * then this block could erroneously appear valid.
3001 * To guard against this, assign a new GUID to the new
3002 * log chain so it doesn't matter what blk points to.
3004 zil_init_log_chain(zilog
, &blk
);
3009 while ((lwb
= list_head(&zilog
->zl_lwb_list
)) != NULL
) {
3010 zh
->zh_log
= lwb
->lwb_blk
;
3011 if (lwb
->lwb_buf
!= NULL
|| lwb
->lwb_max_txg
> txg
)
3013 list_remove(&zilog
->zl_lwb_list
, lwb
);
3014 zio_free(spa
, txg
, &lwb
->lwb_blk
);
3015 zil_free_lwb(zilog
, lwb
);
3018 * If we don't have anything left in the lwb list then
3019 * we've had an allocation failure and we need to zero
3020 * out the zil_header blkptr so that we don't end
3021 * up freeing the same block twice.
3023 if (list_head(&zilog
->zl_lwb_list
) == NULL
)
3024 BP_ZERO(&zh
->zh_log
);
3028 * Remove fastwrite on any blocks that have been pre-allocated for
3029 * the next commit. This prevents fastwrite counter pollution by
3030 * unused, long-lived LWBs.
3032 for (; lwb
!= NULL
; lwb
= list_next(&zilog
->zl_lwb_list
, lwb
)) {
3033 if (lwb
->lwb_fastwrite
&& !lwb
->lwb_write_zio
) {
3034 metaslab_fastwrite_unmark(zilog
->zl_spa
, &lwb
->lwb_blk
);
3035 lwb
->lwb_fastwrite
= 0;
3039 mutex_exit(&zilog
->zl_lock
);
3044 zil_lwb_cons(void *vbuf
, void *unused
, int kmflag
)
3047 list_create(&lwb
->lwb_itxs
, sizeof (itx_t
), offsetof(itx_t
, itx_node
));
3048 list_create(&lwb
->lwb_waiters
, sizeof (zil_commit_waiter_t
),
3049 offsetof(zil_commit_waiter_t
, zcw_node
));
3050 avl_create(&lwb
->lwb_vdev_tree
, zil_lwb_vdev_compare
,
3051 sizeof (zil_vdev_node_t
), offsetof(zil_vdev_node_t
, zv_node
));
3052 mutex_init(&lwb
->lwb_vdev_lock
, NULL
, MUTEX_DEFAULT
, NULL
);
3058 zil_lwb_dest(void *vbuf
, void *unused
)
3061 mutex_destroy(&lwb
->lwb_vdev_lock
);
3062 avl_destroy(&lwb
->lwb_vdev_tree
);
3063 list_destroy(&lwb
->lwb_waiters
);
3064 list_destroy(&lwb
->lwb_itxs
);
3070 zil_lwb_cache
= kmem_cache_create("zil_lwb_cache",
3071 sizeof (lwb_t
), 0, zil_lwb_cons
, zil_lwb_dest
, NULL
, NULL
, NULL
, 0);
3073 zil_zcw_cache
= kmem_cache_create("zil_zcw_cache",
3074 sizeof (zil_commit_waiter_t
), 0, NULL
, NULL
, NULL
, NULL
, NULL
, 0);
3076 zil_ksp
= kstat_create("zfs", 0, "zil", "misc",
3077 KSTAT_TYPE_NAMED
, sizeof (zil_stats
) / sizeof (kstat_named_t
),
3078 KSTAT_FLAG_VIRTUAL
);
3080 if (zil_ksp
!= NULL
) {
3081 zil_ksp
->ks_data
= &zil_stats
;
3082 kstat_install(zil_ksp
);
3089 kmem_cache_destroy(zil_zcw_cache
);
3090 kmem_cache_destroy(zil_lwb_cache
);
3092 if (zil_ksp
!= NULL
) {
3093 kstat_delete(zil_ksp
);
3099 zil_set_sync(zilog_t
*zilog
, uint64_t sync
)
3101 zilog
->zl_sync
= sync
;
3105 zil_set_logbias(zilog_t
*zilog
, uint64_t logbias
)
3107 zilog
->zl_logbias
= logbias
;
3111 zil_alloc(objset_t
*os
, zil_header_t
*zh_phys
)
3115 zilog
= kmem_zalloc(sizeof (zilog_t
), KM_SLEEP
);
3117 zilog
->zl_header
= zh_phys
;
3119 zilog
->zl_spa
= dmu_objset_spa(os
);
3120 zilog
->zl_dmu_pool
= dmu_objset_pool(os
);
3121 zilog
->zl_destroy_txg
= TXG_INITIAL
- 1;
3122 zilog
->zl_logbias
= dmu_objset_logbias(os
);
3123 zilog
->zl_sync
= dmu_objset_syncprop(os
);
3124 zilog
->zl_dirty_max_txg
= 0;
3125 zilog
->zl_last_lwb_opened
= NULL
;
3126 zilog
->zl_last_lwb_latency
= 0;
3128 mutex_init(&zilog
->zl_lock
, NULL
, MUTEX_DEFAULT
, NULL
);
3129 mutex_init(&zilog
->zl_issuer_lock
, NULL
, MUTEX_DEFAULT
, NULL
);
3131 for (int i
= 0; i
< TXG_SIZE
; i
++) {
3132 mutex_init(&zilog
->zl_itxg
[i
].itxg_lock
, NULL
,
3133 MUTEX_DEFAULT
, NULL
);
3136 list_create(&zilog
->zl_lwb_list
, sizeof (lwb_t
),
3137 offsetof(lwb_t
, lwb_node
));
3139 list_create(&zilog
->zl_itx_commit_list
, sizeof (itx_t
),
3140 offsetof(itx_t
, itx_node
));
3142 cv_init(&zilog
->zl_cv_suspend
, NULL
, CV_DEFAULT
, NULL
);
3148 zil_free(zilog_t
*zilog
)
3152 zilog
->zl_stop_sync
= 1;
3154 ASSERT0(zilog
->zl_suspend
);
3155 ASSERT0(zilog
->zl_suspending
);
3157 ASSERT(list_is_empty(&zilog
->zl_lwb_list
));
3158 list_destroy(&zilog
->zl_lwb_list
);
3160 ASSERT(list_is_empty(&zilog
->zl_itx_commit_list
));
3161 list_destroy(&zilog
->zl_itx_commit_list
);
3163 for (i
= 0; i
< TXG_SIZE
; i
++) {
3165 * It's possible for an itx to be generated that doesn't dirty
3166 * a txg (e.g. ztest TX_TRUNCATE). So there's no zil_clean()
3167 * callback to remove the entry. We remove those here.
3169 * Also free up the ziltest itxs.
3171 if (zilog
->zl_itxg
[i
].itxg_itxs
)
3172 zil_itxg_clean(zilog
->zl_itxg
[i
].itxg_itxs
);
3173 mutex_destroy(&zilog
->zl_itxg
[i
].itxg_lock
);
3176 mutex_destroy(&zilog
->zl_issuer_lock
);
3177 mutex_destroy(&zilog
->zl_lock
);
3179 cv_destroy(&zilog
->zl_cv_suspend
);
3181 kmem_free(zilog
, sizeof (zilog_t
));
3185 * Open an intent log.
3188 zil_open(objset_t
*os
, zil_get_data_t
*get_data
)
3190 zilog_t
*zilog
= dmu_objset_zil(os
);
3192 ASSERT3P(zilog
->zl_get_data
, ==, NULL
);
3193 ASSERT3P(zilog
->zl_last_lwb_opened
, ==, NULL
);
3194 ASSERT(list_is_empty(&zilog
->zl_lwb_list
));
3196 zilog
->zl_get_data
= get_data
;
3202 * Close an intent log.
3205 zil_close(zilog_t
*zilog
)
3210 if (!dmu_objset_is_snapshot(zilog
->zl_os
)) {
3211 zil_commit(zilog
, 0);
3213 ASSERT3P(list_tail(&zilog
->zl_lwb_list
), ==, NULL
);
3214 ASSERT0(zilog
->zl_dirty_max_txg
);
3215 ASSERT3B(zilog_is_dirty(zilog
), ==, B_FALSE
);
3218 mutex_enter(&zilog
->zl_lock
);
3219 lwb
= list_tail(&zilog
->zl_lwb_list
);
3221 txg
= zilog
->zl_dirty_max_txg
;
3223 txg
= MAX(zilog
->zl_dirty_max_txg
, lwb
->lwb_max_txg
);
3224 mutex_exit(&zilog
->zl_lock
);
3227 * We need to use txg_wait_synced() to wait long enough for the
3228 * ZIL to be clean, and to wait for all pending lwbs to be
3232 txg_wait_synced(zilog
->zl_dmu_pool
, txg
);
3234 if (zilog_is_dirty(zilog
))
3235 zfs_dbgmsg("zil (%px) is dirty, txg %llu", zilog
, txg
);
3236 if (txg
< spa_freeze_txg(zilog
->zl_spa
))
3237 VERIFY(!zilog_is_dirty(zilog
));
3239 zilog
->zl_get_data
= NULL
;
3242 * We should have only one lwb left on the list; remove it now.
3244 mutex_enter(&zilog
->zl_lock
);
3245 lwb
= list_head(&zilog
->zl_lwb_list
);
3247 ASSERT3P(lwb
, ==, list_tail(&zilog
->zl_lwb_list
));
3248 ASSERT3S(lwb
->lwb_state
, !=, LWB_STATE_ISSUED
);
3250 if (lwb
->lwb_fastwrite
)
3251 metaslab_fastwrite_unmark(zilog
->zl_spa
, &lwb
->lwb_blk
);
3253 list_remove(&zilog
->zl_lwb_list
, lwb
);
3254 zio_buf_free(lwb
->lwb_buf
, lwb
->lwb_sz
);
3255 zil_free_lwb(zilog
, lwb
);
3257 mutex_exit(&zilog
->zl_lock
);
3260 static char *suspend_tag
= "zil suspending";
3263 * Suspend an intent log. While in suspended mode, we still honor
3264 * synchronous semantics, but we rely on txg_wait_synced() to do it.
3265 * On old version pools, we suspend the log briefly when taking a
3266 * snapshot so that it will have an empty intent log.
3268 * Long holds are not really intended to be used the way we do here --
3269 * held for such a short time. A concurrent caller of dsl_dataset_long_held()
3270 * could fail. Therefore we take pains to only put a long hold if it is
3271 * actually necessary. Fortunately, it will only be necessary if the
3272 * objset is currently mounted (or the ZVOL equivalent). In that case it
3273 * will already have a long hold, so we are not really making things any worse.
3275 * Ideally, we would locate the existing long-holder (i.e. the zfsvfs_t or
3276 * zvol_state_t), and use their mechanism to prevent their hold from being
3277 * dropped (e.g. VFS_HOLD()). However, that would be even more pain for
3280 * if cookiep == NULL, this does both the suspend & resume.
3281 * Otherwise, it returns with the dataset "long held", and the cookie
3282 * should be passed into zil_resume().
3285 zil_suspend(const char *osname
, void **cookiep
)
3289 const zil_header_t
*zh
;
3292 error
= dmu_objset_hold(osname
, suspend_tag
, &os
);
3295 zilog
= dmu_objset_zil(os
);
3297 mutex_enter(&zilog
->zl_lock
);
3298 zh
= zilog
->zl_header
;
3300 if (zh
->zh_flags
& ZIL_REPLAY_NEEDED
) { /* unplayed log */
3301 mutex_exit(&zilog
->zl_lock
);
3302 dmu_objset_rele(os
, suspend_tag
);
3303 return (SET_ERROR(EBUSY
));
3307 * Don't put a long hold in the cases where we can avoid it. This
3308 * is when there is no cookie so we are doing a suspend & resume
3309 * (i.e. called from zil_vdev_offline()), and there's nothing to do
3310 * for the suspend because it's already suspended, or there's no ZIL.
3312 if (cookiep
== NULL
&& !zilog
->zl_suspending
&&
3313 (zilog
->zl_suspend
> 0 || BP_IS_HOLE(&zh
->zh_log
))) {
3314 mutex_exit(&zilog
->zl_lock
);
3315 dmu_objset_rele(os
, suspend_tag
);
3319 dsl_dataset_long_hold(dmu_objset_ds(os
), suspend_tag
);
3320 dsl_pool_rele(dmu_objset_pool(os
), suspend_tag
);
3322 zilog
->zl_suspend
++;
3324 if (zilog
->zl_suspend
> 1) {
3326 * Someone else is already suspending it.
3327 * Just wait for them to finish.
3330 while (zilog
->zl_suspending
)
3331 cv_wait(&zilog
->zl_cv_suspend
, &zilog
->zl_lock
);
3332 mutex_exit(&zilog
->zl_lock
);
3334 if (cookiep
== NULL
)
3342 * If there is no pointer to an on-disk block, this ZIL must not
3343 * be active (e.g. filesystem not mounted), so there's nothing
3346 if (BP_IS_HOLE(&zh
->zh_log
)) {
3347 ASSERT(cookiep
!= NULL
); /* fast path already handled */
3350 mutex_exit(&zilog
->zl_lock
);
3355 * The ZIL has work to do. Ensure that the associated encryption
3356 * key will remain mapped while we are committing the log by
3357 * grabbing a reference to it. If the key isn't loaded we have no
3358 * choice but to return an error until the wrapping key is loaded.
3360 if (os
->os_encrypted
&&
3361 dsl_dataset_create_key_mapping(dmu_objset_ds(os
)) != 0) {
3362 zilog
->zl_suspend
--;
3363 mutex_exit(&zilog
->zl_lock
);
3364 dsl_dataset_long_rele(dmu_objset_ds(os
), suspend_tag
);
3365 dsl_dataset_rele(dmu_objset_ds(os
), suspend_tag
);
3366 return (SET_ERROR(EACCES
));
3369 zilog
->zl_suspending
= B_TRUE
;
3370 mutex_exit(&zilog
->zl_lock
);
3373 * We need to use zil_commit_impl to ensure we wait for all
3374 * LWB_STATE_OPENED and LWB_STATE_ISSUED lwbs to be committed
3375 * to disk before proceeding. If we used zil_commit instead, it
3376 * would just call txg_wait_synced(), because zl_suspend is set.
3377 * txg_wait_synced() doesn't wait for these lwb's to be
3378 * LWB_STATE_FLUSH_DONE before returning.
3380 zil_commit_impl(zilog
, 0);
3383 * Now that we've ensured all lwb's are LWB_STATE_FLUSH_DONE, we
3384 * use txg_wait_synced() to ensure the data from the zilog has
3385 * migrated to the main pool before calling zil_destroy().
3387 txg_wait_synced(zilog
->zl_dmu_pool
, 0);
3389 zil_destroy(zilog
, B_FALSE
);
3391 mutex_enter(&zilog
->zl_lock
);
3392 zilog
->zl_suspending
= B_FALSE
;
3393 cv_broadcast(&zilog
->zl_cv_suspend
);
3394 mutex_exit(&zilog
->zl_lock
);
3396 if (os
->os_encrypted
)
3397 dsl_dataset_remove_key_mapping(dmu_objset_ds(os
));
3399 if (cookiep
== NULL
)
3407 zil_resume(void *cookie
)
3409 objset_t
*os
= cookie
;
3410 zilog_t
*zilog
= dmu_objset_zil(os
);
3412 mutex_enter(&zilog
->zl_lock
);
3413 ASSERT(zilog
->zl_suspend
!= 0);
3414 zilog
->zl_suspend
--;
3415 mutex_exit(&zilog
->zl_lock
);
3416 dsl_dataset_long_rele(dmu_objset_ds(os
), suspend_tag
);
3417 dsl_dataset_rele(dmu_objset_ds(os
), suspend_tag
);
3420 typedef struct zil_replay_arg
{
3421 zil_replay_func_t
**zr_replay
;
3423 boolean_t zr_byteswap
;
3428 zil_replay_error(zilog_t
*zilog
, lr_t
*lr
, int error
)
3430 char name
[ZFS_MAX_DATASET_NAME_LEN
];
3432 zilog
->zl_replaying_seq
--; /* didn't actually replay this one */
3434 dmu_objset_name(zilog
->zl_os
, name
);
3436 cmn_err(CE_WARN
, "ZFS replay transaction error %d, "
3437 "dataset %s, seq 0x%llx, txtype %llu %s\n", error
, name
,
3438 (u_longlong_t
)lr
->lrc_seq
,
3439 (u_longlong_t
)(lr
->lrc_txtype
& ~TX_CI
),
3440 (lr
->lrc_txtype
& TX_CI
) ? "CI" : "");
3446 zil_replay_log_record(zilog_t
*zilog
, lr_t
*lr
, void *zra
, uint64_t claim_txg
)
3448 zil_replay_arg_t
*zr
= zra
;
3449 const zil_header_t
*zh
= zilog
->zl_header
;
3450 uint64_t reclen
= lr
->lrc_reclen
;
3451 uint64_t txtype
= lr
->lrc_txtype
;
3454 zilog
->zl_replaying_seq
= lr
->lrc_seq
;
3456 if (lr
->lrc_seq
<= zh
->zh_replay_seq
) /* already replayed */
3459 if (lr
->lrc_txg
< claim_txg
) /* already committed */
3462 /* Strip case-insensitive bit, still present in log record */
3465 if (txtype
== 0 || txtype
>= TX_MAX_TYPE
)
3466 return (zil_replay_error(zilog
, lr
, EINVAL
));
3469 * If this record type can be logged out of order, the object
3470 * (lr_foid) may no longer exist. That's legitimate, not an error.
3472 if (TX_OOO(txtype
)) {
3473 error
= dmu_object_info(zilog
->zl_os
,
3474 LR_FOID_GET_OBJ(((lr_ooo_t
*)lr
)->lr_foid
), NULL
);
3475 if (error
== ENOENT
|| error
== EEXIST
)
3480 * Make a copy of the data so we can revise and extend it.
3482 bcopy(lr
, zr
->zr_lr
, reclen
);
3485 * If this is a TX_WRITE with a blkptr, suck in the data.
3487 if (txtype
== TX_WRITE
&& reclen
== sizeof (lr_write_t
)) {
3488 error
= zil_read_log_data(zilog
, (lr_write_t
*)lr
,
3489 zr
->zr_lr
+ reclen
);
3491 return (zil_replay_error(zilog
, lr
, error
));
3495 * The log block containing this lr may have been byteswapped
3496 * so that we can easily examine common fields like lrc_txtype.
3497 * However, the log is a mix of different record types, and only the
3498 * replay vectors know how to byteswap their records. Therefore, if
3499 * the lr was byteswapped, undo it before invoking the replay vector.
3501 if (zr
->zr_byteswap
)
3502 byteswap_uint64_array(zr
->zr_lr
, reclen
);
3505 * We must now do two things atomically: replay this log record,
3506 * and update the log header sequence number to reflect the fact that
3507 * we did so. At the end of each replay function the sequence number
3508 * is updated if we are in replay mode.
3510 error
= zr
->zr_replay
[txtype
](zr
->zr_arg
, zr
->zr_lr
, zr
->zr_byteswap
);
3513 * The DMU's dnode layer doesn't see removes until the txg
3514 * commits, so a subsequent claim can spuriously fail with
3515 * EEXIST. So if we receive any error we try syncing out
3516 * any removes then retry the transaction. Note that we
3517 * specify B_FALSE for byteswap now, so we don't do it twice.
3519 txg_wait_synced(spa_get_dsl(zilog
->zl_spa
), 0);
3520 error
= zr
->zr_replay
[txtype
](zr
->zr_arg
, zr
->zr_lr
, B_FALSE
);
3522 return (zil_replay_error(zilog
, lr
, error
));
3529 zil_incr_blks(zilog_t
*zilog
, blkptr_t
*bp
, void *arg
, uint64_t claim_txg
)
3531 zilog
->zl_replay_blks
++;
3537 * If this dataset has a non-empty intent log, replay it and destroy it.
3540 zil_replay(objset_t
*os
, void *arg
, zil_replay_func_t
*replay_func
[TX_MAX_TYPE
])
3542 zilog_t
*zilog
= dmu_objset_zil(os
);
3543 const zil_header_t
*zh
= zilog
->zl_header
;
3544 zil_replay_arg_t zr
;
3546 if ((zh
->zh_flags
& ZIL_REPLAY_NEEDED
) == 0) {
3547 zil_destroy(zilog
, B_TRUE
);
3551 zr
.zr_replay
= replay_func
;
3553 zr
.zr_byteswap
= BP_SHOULD_BYTESWAP(&zh
->zh_log
);
3554 zr
.zr_lr
= vmem_alloc(2 * SPA_MAXBLOCKSIZE
, KM_SLEEP
);
3557 * Wait for in-progress removes to sync before starting replay.
3559 txg_wait_synced(zilog
->zl_dmu_pool
, 0);
3561 zilog
->zl_replay
= B_TRUE
;
3562 zilog
->zl_replay_time
= ddi_get_lbolt();
3563 ASSERT(zilog
->zl_replay_blks
== 0);
3564 (void) zil_parse(zilog
, zil_incr_blks
, zil_replay_log_record
, &zr
,
3565 zh
->zh_claim_txg
, B_TRUE
);
3566 vmem_free(zr
.zr_lr
, 2 * SPA_MAXBLOCKSIZE
);
3568 zil_destroy(zilog
, B_FALSE
);
3569 txg_wait_synced(zilog
->zl_dmu_pool
, zilog
->zl_destroy_txg
);
3570 zilog
->zl_replay
= B_FALSE
;
3574 zil_replaying(zilog_t
*zilog
, dmu_tx_t
*tx
)
3576 if (zilog
->zl_sync
== ZFS_SYNC_DISABLED
)
3579 if (zilog
->zl_replay
) {
3580 dsl_dataset_dirty(dmu_objset_ds(zilog
->zl_os
), tx
);
3581 zilog
->zl_replayed_seq
[dmu_tx_get_txg(tx
) & TXG_MASK
] =
3582 zilog
->zl_replaying_seq
;
3591 zil_reset(const char *osname
, void *arg
)
3595 error
= zil_suspend(osname
, NULL
);
3596 /* EACCES means crypto key not loaded */
3597 if ((error
== EACCES
) || (error
== EBUSY
))
3598 return (SET_ERROR(error
));
3600 return (SET_ERROR(EEXIST
));
3604 #if defined(_KERNEL)
3605 EXPORT_SYMBOL(zil_alloc
);
3606 EXPORT_SYMBOL(zil_free
);
3607 EXPORT_SYMBOL(zil_open
);
3608 EXPORT_SYMBOL(zil_close
);
3609 EXPORT_SYMBOL(zil_replay
);
3610 EXPORT_SYMBOL(zil_replaying
);
3611 EXPORT_SYMBOL(zil_destroy
);
3612 EXPORT_SYMBOL(zil_destroy_sync
);
3613 EXPORT_SYMBOL(zil_itx_create
);
3614 EXPORT_SYMBOL(zil_itx_destroy
);
3615 EXPORT_SYMBOL(zil_itx_assign
);
3616 EXPORT_SYMBOL(zil_commit
);
3617 EXPORT_SYMBOL(zil_claim
);
3618 EXPORT_SYMBOL(zil_check_log_chain
);
3619 EXPORT_SYMBOL(zil_sync
);
3620 EXPORT_SYMBOL(zil_clean
);
3621 EXPORT_SYMBOL(zil_suspend
);
3622 EXPORT_SYMBOL(zil_resume
);
3623 EXPORT_SYMBOL(zil_lwb_add_block
);
3624 EXPORT_SYMBOL(zil_bp_tree_add
);
3625 EXPORT_SYMBOL(zil_set_sync
);
3626 EXPORT_SYMBOL(zil_set_logbias
);
3629 module_param(zfs_commit_timeout_pct
, int, 0644);
3630 MODULE_PARM_DESC(zfs_commit_timeout_pct
, "ZIL block open timeout percentage");
3632 module_param(zil_replay_disable
, int, 0644);
3633 MODULE_PARM_DESC(zil_replay_disable
, "Disable intent logging replay");
3635 module_param(zil_nocacheflush
, int, 0644);
3636 MODULE_PARM_DESC(zil_nocacheflush
, "Disable ZIL cache flushes");
3638 module_param(zil_slog_bulk
, ulong
, 0644);
3639 MODULE_PARM_DESC(zil_slog_bulk
, "Limit in bytes slog sync writes per commit");