1 /*
2 * CDDL HEADER START
3 *
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.
7 *
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.
12 *
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]
18 *
19 * CDDL HEADER END
20 */
21 /*
22 * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
23 * Copyright (c) 2013 by Delphix. All rights reserved.
24 */
25
26 /* Portions Copyright 2010 Robert Milkowski */
27
28 #include <sys/zfs_context.h>
29 #include <sys/spa.h>
30 #include <sys/dmu.h>
31 #include <sys/zap.h>
32 #include <sys/arc.h>
33 #include <sys/stat.h>
34 #include <sys/resource.h>
35 #include <sys/zil.h>
36 #include <sys/zil_impl.h>
37 #include <sys/dsl_dataset.h>
38 #include <sys/vdev_impl.h>
39 #include <sys/dmu_tx.h>
40 #include <sys/dsl_pool.h>
41
42 /*
43 * The zfs intent log (ZIL) saves transaction records of system calls
44 * that change the file system in memory with enough information
45 * to be able to replay them. These are stored in memory until
46 * either the DMU transaction group (txg) commits them to the stable pool
47 * and they can be discarded, or they are flushed to the stable log
48 * (also in the pool) due to a fsync, O_DSYNC or other synchronous
49 * requirement. In the event of a panic or power fail then those log
50 * records (transactions) are replayed.
51 *
52 * There is one ZIL per file system. Its on-disk (pool) format consists
53 * of 3 parts:
54 *
55 * - ZIL header
56 * - ZIL blocks
57 * - ZIL records
58 *
59 * A log record holds a system call transaction. Log blocks can
60 * hold many log records and the blocks are chained together.
61 * Each ZIL block contains a block pointer (blkptr_t) to the next
62 * ZIL block in the chain. The ZIL header points to the first
63 * block in the chain. Note there is not a fixed place in the pool
64 * to hold blocks. They are dynamically allocated and freed as
65 * needed from the blocks available. Figure X shows the ZIL structure:
66 */
67
68 /*
69 * Disable intent logging replay. This global ZIL switch affects all pools.
70 */
71 int zil_replay_disable = 0;
72
73 /*
74 * Tunable parameter for debugging or performance analysis. Setting
75 * zfs_nocacheflush will cause corruption on power loss if a volatile
76 * out-of-order write cache is enabled.
77 */
78 boolean_t zfs_nocacheflush = B_FALSE;
79
80 static kmem_cache_t *zil_lwb_cache;
81
82 static void zil_async_to_sync(zilog_t *zilog, uint64_t foid);
83
84 #define LWB_EMPTY(lwb) ((BP_GET_LSIZE(&lwb->lwb_blk) - \
85 sizeof (zil_chain_t)) == (lwb->lwb_sz - lwb->lwb_nused))
86
87
88 /*
89 * ziltest is by and large an ugly hack, but very useful in
90 * checking replay without tedious work.
91 * When running ziltest we want to keep all itx's and so maintain
92 * a single list in the zl_itxg[] that uses a high txg: ZILTEST_TXG
93 * We subtract TXG_CONCURRENT_STATES to allow for common code.
94 */
95 #define ZILTEST_TXG (UINT64_MAX - TXG_CONCURRENT_STATES)
96
97 static int
98 zil_bp_compare(const void *x1, const void *x2)
99 {
100 const dva_t *dva1 = &((zil_bp_node_t *)x1)->zn_dva;
101 const dva_t *dva2 = &((zil_bp_node_t *)x2)->zn_dva;
102
103 if (DVA_GET_VDEV(dva1) < DVA_GET_VDEV(dva2))
104 return (-1);
105 if (DVA_GET_VDEV(dva1) > DVA_GET_VDEV(dva2))
106 return (1);
107
108 if (DVA_GET_OFFSET(dva1) < DVA_GET_OFFSET(dva2))
109 return (-1);
110 if (DVA_GET_OFFSET(dva1) > DVA_GET_OFFSET(dva2))
111 return (1);
112
113 return (0);
114 }
115
116 static void
117 zil_bp_tree_init(zilog_t *zilog)
118 {
119 avl_create(&zilog->zl_bp_tree, zil_bp_compare,
120 sizeof (zil_bp_node_t), offsetof(zil_bp_node_t, zn_node));
121 }
122
123 static void
124 zil_bp_tree_fini(zilog_t *zilog)
125 {
126 avl_tree_t *t = &zilog->zl_bp_tree;
127 zil_bp_node_t *zn;
128 void *cookie = NULL;
129
130 while ((zn = avl_destroy_nodes(t, &cookie)) != NULL)
131 kmem_free(zn, sizeof (zil_bp_node_t));
132
133 avl_destroy(t);
134 }
135
136 int
137 zil_bp_tree_add(zilog_t *zilog, const blkptr_t *bp)
138 {
139 avl_tree_t *t = &zilog->zl_bp_tree;
140 const dva_t *dva = BP_IDENTITY(bp);
141 zil_bp_node_t *zn;
142 avl_index_t where;
143
144 if (avl_find(t, dva, &where) != NULL)
145 return (SET_ERROR(EEXIST));
146
147 zn = kmem_alloc(sizeof (zil_bp_node_t), KM_SLEEP);
148 zn->zn_dva = *dva;
149 avl_insert(t, zn, where);
150
151 return (0);
152 }
153
154 static zil_header_t *
155 zil_header_in_syncing_context(zilog_t *zilog)
156 {
157 return ((zil_header_t *)zilog->zl_header);
158 }
159
160 static void
161 zil_init_log_chain(zilog_t *zilog, blkptr_t *bp)
162 {
163 zio_cksum_t *zc = &bp->blk_cksum;
164
165 zc->zc_word[ZIL_ZC_GUID_0] = spa_get_random(-1ULL);
166 zc->zc_word[ZIL_ZC_GUID_1] = spa_get_random(-1ULL);
167 zc->zc_word[ZIL_ZC_OBJSET] = dmu_objset_id(zilog->zl_os);
168 zc->zc_word[ZIL_ZC_SEQ] = 1ULL;
169 }
170
171 /*
172 * Read a log block and make sure it's valid.
173 */
174 static int
175 zil_read_log_block(zilog_t *zilog, const blkptr_t *bp, blkptr_t *nbp, void *dst,
176 char **end)
177 {
178 enum zio_flag zio_flags = ZIO_FLAG_CANFAIL;
179 uint32_t aflags = ARC_WAIT;
180 arc_buf_t *abuf = NULL;
181 zbookmark_t zb;
182 int error;
183
184 if (zilog->zl_header->zh_claim_txg == 0)
185 zio_flags |= ZIO_FLAG_SPECULATIVE | ZIO_FLAG_SCRUB;
186
187 if (!(zilog->zl_header->zh_flags & ZIL_CLAIM_LR_SEQ_VALID))
188 zio_flags |= ZIO_FLAG_SPECULATIVE;
189
190 SET_BOOKMARK(&zb, bp->blk_cksum.zc_word[ZIL_ZC_OBJSET],
191 ZB_ZIL_OBJECT, ZB_ZIL_LEVEL, bp->blk_cksum.zc_word[ZIL_ZC_SEQ]);
192
193 error = arc_read(NULL, zilog->zl_spa, bp, arc_getbuf_func, &abuf,
194 ZIO_PRIORITY_SYNC_READ, zio_flags, &aflags, &zb);
195
196 if (error == 0) {
197 zio_cksum_t cksum = bp->blk_cksum;
198
199 /*
200 * Validate the checksummed log block.
201 *
202 * Sequence numbers should be... sequential. The checksum
203 * verifier for the next block should be bp's checksum plus 1.
204 *
205 * Also check the log chain linkage and size used.
206 */
207 cksum.zc_word[ZIL_ZC_SEQ]++;
208
209 if (BP_GET_CHECKSUM(bp) == ZIO_CHECKSUM_ZILOG2) {
210 zil_chain_t *zilc = abuf->b_data;
211 char *lr = (char *)(zilc + 1);
212 uint64_t len = zilc->zc_nused - sizeof (zil_chain_t);
213
214 if (bcmp(&cksum, &zilc->zc_next_blk.blk_cksum,
215 sizeof (cksum)) || BP_IS_HOLE(&zilc->zc_next_blk)) {
216 error = SET_ERROR(ECKSUM);
217 } else {
218 bcopy(lr, dst, len);
219 *end = (char *)dst + len;
220 *nbp = zilc->zc_next_blk;
221 }
222 } else {
223 char *lr = abuf->b_data;
224 uint64_t size = BP_GET_LSIZE(bp);
225 zil_chain_t *zilc = (zil_chain_t *)(lr + size) - 1;
226
227 if (bcmp(&cksum, &zilc->zc_next_blk.blk_cksum,
228 sizeof (cksum)) || BP_IS_HOLE(&zilc->zc_next_blk) ||
229 (zilc->zc_nused > (size - sizeof (*zilc)))) {
230 error = SET_ERROR(ECKSUM);
231 } else {
232 bcopy(lr, dst, zilc->zc_nused);
233 *end = (char *)dst + zilc->zc_nused;
234 *nbp = zilc->zc_next_blk;
235 }
236 }
237
238 VERIFY(arc_buf_remove_ref(abuf, &abuf));
239 }
240
241 return (error);
242 }
243
244 /*
245 * Read a TX_WRITE log data block.
246 */
247 static int
248 zil_read_log_data(zilog_t *zilog, const lr_write_t *lr, void *wbuf)
249 {
250 enum zio_flag zio_flags = ZIO_FLAG_CANFAIL;
251 const blkptr_t *bp = &lr->lr_blkptr;
252 uint32_t aflags = ARC_WAIT;
253 arc_buf_t *abuf = NULL;
254 zbookmark_t zb;
255 int error;
256
257 if (BP_IS_HOLE(bp)) {
258 if (wbuf != NULL)
259 bzero(wbuf, MAX(BP_GET_LSIZE(bp), lr->lr_length));
260 return (0);
261 }
262
263 if (zilog->zl_header->zh_claim_txg == 0)
264 zio_flags |= ZIO_FLAG_SPECULATIVE | ZIO_FLAG_SCRUB;
265
266 SET_BOOKMARK(&zb, dmu_objset_id(zilog->zl_os), lr->lr_foid,
267 ZB_ZIL_LEVEL, lr->lr_offset / BP_GET_LSIZE(bp));
268
269 error = arc_read(NULL, zilog->zl_spa, bp, arc_getbuf_func, &abuf,
270 ZIO_PRIORITY_SYNC_READ, zio_flags, &aflags, &zb);
271
272 if (error == 0) {
273 if (wbuf != NULL)
274 bcopy(abuf->b_data, wbuf, arc_buf_size(abuf));
275 (void) arc_buf_remove_ref(abuf, &abuf);
276 }
277
278 return (error);
279 }
280
281 /*
282 * Parse the intent log, and call parse_func for each valid record within.
283 */
284 int
285 zil_parse(zilog_t *zilog, zil_parse_blk_func_t *parse_blk_func,
286 zil_parse_lr_func_t *parse_lr_func, void *arg, uint64_t txg)
287 {
288 const zil_header_t *zh = zilog->zl_header;
289 boolean_t claimed = !!zh->zh_claim_txg;
290 uint64_t claim_blk_seq = claimed ? zh->zh_claim_blk_seq : UINT64_MAX;
291 uint64_t claim_lr_seq = claimed ? zh->zh_claim_lr_seq : UINT64_MAX;
292 uint64_t max_blk_seq = 0;
293 uint64_t max_lr_seq = 0;
294 uint64_t blk_count = 0;
295 uint64_t lr_count = 0;
296 blkptr_t blk, next_blk;
297 char *lrbuf, *lrp;
298 int error = 0;
299
300 /*
301 * Old logs didn't record the maximum zh_claim_lr_seq.
302 */
303 if (!(zh->zh_flags & ZIL_CLAIM_LR_SEQ_VALID))
304 claim_lr_seq = UINT64_MAX;
305
306 /*
307 * Starting at the block pointed to by zh_log we read the log chain.
308 * For each block in the chain we strongly check that block to
309 * ensure its validity. We stop when an invalid block is found.
310 * For each block pointer in the chain we call parse_blk_func().
311 * For each record in each valid block we call parse_lr_func().
312 * If the log has been claimed, stop if we encounter a sequence
313 * number greater than the highest claimed sequence number.
314 */
315 lrbuf = zio_buf_alloc(SPA_MAXBLOCKSIZE);
316 zil_bp_tree_init(zilog);
317
318 for (blk = zh->zh_log; !BP_IS_HOLE(&blk); blk = next_blk) {
319 uint64_t blk_seq = blk.blk_cksum.zc_word[ZIL_ZC_SEQ];
320 int reclen;
321 char *end;
322
323 if (blk_seq > claim_blk_seq)
324 break;
325 if ((error = parse_blk_func(zilog, &blk, arg, txg)) != 0)
326 break;
327 ASSERT3U(max_blk_seq, <, blk_seq);
328 max_blk_seq = blk_seq;
329 blk_count++;
330
331 if (max_lr_seq == claim_lr_seq && max_blk_seq == claim_blk_seq)
332 break;
333
334 error = zil_read_log_block(zilog, &blk, &next_blk, lrbuf, &end);
335 if (error != 0)
336 break;
337
338 for (lrp = lrbuf; lrp < end; lrp += reclen) {
339 lr_t *lr = (lr_t *)lrp;
340 reclen = lr->lrc_reclen;
341 ASSERT3U(reclen, >=, sizeof (lr_t));
342 if (lr->lrc_seq > claim_lr_seq)
343 goto done;
344 if ((error = parse_lr_func(zilog, lr, arg, txg)) != 0)
345 goto done;
346 ASSERT3U(max_lr_seq, <, lr->lrc_seq);
347 max_lr_seq = lr->lrc_seq;
348 lr_count++;
349 }
350 }
351 done:
352 zilog->zl_parse_error = error;
353 zilog->zl_parse_blk_seq = max_blk_seq;
354 zilog->zl_parse_lr_seq = max_lr_seq;
355 zilog->zl_parse_blk_count = blk_count;
356 zilog->zl_parse_lr_count = lr_count;
357
358 ASSERT(!claimed || !(zh->zh_flags & ZIL_CLAIM_LR_SEQ_VALID) ||
359 (max_blk_seq == claim_blk_seq && max_lr_seq == claim_lr_seq));
360
361 zil_bp_tree_fini(zilog);
362 zio_buf_free(lrbuf, SPA_MAXBLOCKSIZE);
363
364 return (error);
365 }
366
367 static int
368 zil_claim_log_block(zilog_t *zilog, blkptr_t *bp, void *tx, uint64_t first_txg)
369 {
370 /*
371 * Claim log block if not already committed and not already claimed.
372 * If tx == NULL, just verify that the block is claimable.
373 */
374 if (bp->blk_birth < first_txg || zil_bp_tree_add(zilog, bp) != 0)
375 return (0);
376
377 return (zio_wait(zio_claim(NULL, zilog->zl_spa,
378 tx == NULL ? 0 : first_txg, bp, spa_claim_notify, NULL,
379 ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE | ZIO_FLAG_SCRUB)));
380 }
381
382 static int
383 zil_claim_log_record(zilog_t *zilog, lr_t *lrc, void *tx, uint64_t first_txg)
384 {
385 lr_write_t *lr = (lr_write_t *)lrc;
386 int error;
387
388 if (lrc->lrc_txtype != TX_WRITE)
389 return (0);
390
391 /*
392 * If the block is not readable, don't claim it. This can happen
393 * in normal operation when a log block is written to disk before
394 * some of the dmu_sync() blocks it points to. In this case, the
395 * transaction cannot have been committed to anyone (we would have
396 * waited for all writes to be stable first), so it is semantically
397 * correct to declare this the end of the log.
398 */
399 if (lr->lr_blkptr.blk_birth >= first_txg &&
400 (error = zil_read_log_data(zilog, lr, NULL)) != 0)
401 return (error);
402 return (zil_claim_log_block(zilog, &lr->lr_blkptr, tx, first_txg));
403 }
404
405 /* ARGSUSED */
406 static int
407 zil_free_log_block(zilog_t *zilog, blkptr_t *bp, void *tx, uint64_t claim_txg)
408 {
409 zio_free_zil(zilog->zl_spa, dmu_tx_get_txg(tx), bp);
410
411 return (0);
412 }
413
414 static int
415 zil_free_log_record(zilog_t *zilog, lr_t *lrc, void *tx, uint64_t claim_txg)
416 {
417 lr_write_t *lr = (lr_write_t *)lrc;
418 blkptr_t *bp = &lr->lr_blkptr;
419
420 /*
421 * If we previously claimed it, we need to free it.
422 */
423 if (claim_txg != 0 && lrc->lrc_txtype == TX_WRITE &&
424 bp->blk_birth >= claim_txg && zil_bp_tree_add(zilog, bp) == 0)
425 zio_free(zilog->zl_spa, dmu_tx_get_txg(tx), bp);
426
427 return (0);
428 }
429
430 static lwb_t *
431 zil_alloc_lwb(zilog_t *zilog, blkptr_t *bp, uint64_t txg)
432 {
433 lwb_t *lwb;
434
435 lwb = kmem_cache_alloc(zil_lwb_cache, KM_SLEEP);
436 lwb->lwb_zilog = zilog;
437 lwb->lwb_blk = *bp;
438 lwb->lwb_buf = zio_buf_alloc(BP_GET_LSIZE(bp));
439 lwb->lwb_max_txg = txg;
440 lwb->lwb_zio = NULL;
441 lwb->lwb_tx = NULL;
442 if (BP_GET_CHECKSUM(bp) == ZIO_CHECKSUM_ZILOG2) {
443 lwb->lwb_nused = sizeof (zil_chain_t);
444 lwb->lwb_sz = BP_GET_LSIZE(bp);
445 } else {
446 lwb->lwb_nused = 0;
447 lwb->lwb_sz = BP_GET_LSIZE(bp) - sizeof (zil_chain_t);
448 }
449
450 mutex_enter(&zilog->zl_lock);
451 list_insert_tail(&zilog->zl_lwb_list, lwb);
452 mutex_exit(&zilog->zl_lock);
453
454 return (lwb);
455 }
456
457 /*
458 * Called when we create in-memory log transactions so that we know
459 * to cleanup the itxs at the end of spa_sync().
460 */
461 void
462 zilog_dirty(zilog_t *zilog, uint64_t txg)
463 {
464 dsl_pool_t *dp = zilog->zl_dmu_pool;
465 dsl_dataset_t *ds = dmu_objset_ds(zilog->zl_os);
466
467 if (dsl_dataset_is_snapshot(ds))
468 panic("dirtying snapshot!");
469
470 if (txg_list_add(&dp->dp_dirty_zilogs, zilog, txg)) {
471 /* up the hold count until we can be written out */
472 dmu_buf_add_ref(ds->ds_dbuf, zilog);
473 }
474 }
475
476 boolean_t
477 zilog_is_dirty(zilog_t *zilog)
478 {
479 dsl_pool_t *dp = zilog->zl_dmu_pool;
480
481 for (int t = 0; t < TXG_SIZE; t++) {
482 if (txg_list_member(&dp->dp_dirty_zilogs, zilog, t))
483 return (B_TRUE);
484 }
485 return (B_FALSE);
486 }
487
488 /*
489 * Create an on-disk intent log.
490 */
491 static lwb_t *
492 zil_create(zilog_t *zilog)
493 {
494 const zil_header_t *zh = zilog->zl_header;
495 lwb_t *lwb = NULL;
496 uint64_t txg = 0;
497 dmu_tx_t *tx = NULL;
498 blkptr_t blk;
499 int error = 0;
500
501 /*
502 * Wait for any previous destroy to complete.
503 */
504 txg_wait_synced(zilog->zl_dmu_pool, zilog->zl_destroy_txg);
505
506 ASSERT(zh->zh_claim_txg == 0);
507 ASSERT(zh->zh_replay_seq == 0);
508
509 blk = zh->zh_log;
510
511 /*
512 * Allocate an initial log block if:
513 * - there isn't one already
514 * - the existing block is the wrong endianess
515 */
516 if (BP_IS_HOLE(&blk) || BP_SHOULD_BYTESWAP(&blk)) {
517 tx = dmu_tx_create(zilog->zl_os);
518 VERIFY(dmu_tx_assign(tx, TXG_WAIT) == 0);
519 dsl_dataset_dirty(dmu_objset_ds(zilog->zl_os), tx);
520 txg = dmu_tx_get_txg(tx);
521
522 if (!BP_IS_HOLE(&blk)) {
523 zio_free_zil(zilog->zl_spa, txg, &blk);
524 BP_ZERO(&blk);
525 }
526
527 error = zio_alloc_zil(zilog->zl_spa, txg, &blk, NULL,
528 ZIL_MIN_BLKSZ, zilog->zl_logbias == ZFS_LOGBIAS_LATENCY);
529
530 if (error == 0)
531 zil_init_log_chain(zilog, &blk);
532 }
533
534 /*
535 * Allocate a log write buffer (lwb) for the first log block.
536 */
537 if (error == 0)
538 lwb = zil_alloc_lwb(zilog, &blk, txg);
539
540 /*
541 * If we just allocated the first log block, commit our transaction
542 * and wait for zil_sync() to stuff the block poiner into zh_log.
543 * (zh is part of the MOS, so we cannot modify it in open context.)
544 */
545 if (tx != NULL) {
546 dmu_tx_commit(tx);
547 txg_wait_synced(zilog->zl_dmu_pool, txg);
548 }
549
550 ASSERT(bcmp(&blk, &zh->zh_log, sizeof (blk)) == 0);
551
552 return (lwb);
553 }
554
555 /*
556 * In one tx, free all log blocks and clear the log header.
557 * If keep_first is set, then we're replaying a log with no content.
558 * We want to keep the first block, however, so that the first
559 * synchronous transaction doesn't require a txg_wait_synced()
560 * in zil_create(). We don't need to txg_wait_synced() here either
561 * when keep_first is set, because both zil_create() and zil_destroy()
562 * will wait for any in-progress destroys to complete.
563 */
564 void
565 zil_destroy(zilog_t *zilog, boolean_t keep_first)
566 {
567 const zil_header_t *zh = zilog->zl_header;
568 lwb_t *lwb;
569 dmu_tx_t *tx;
570 uint64_t txg;
571
572 /*
573 * Wait for any previous destroy to complete.
574 */
575 txg_wait_synced(zilog->zl_dmu_pool, zilog->zl_destroy_txg);
576
577 zilog->zl_old_header = *zh; /* debugging aid */
578
579 if (BP_IS_HOLE(&zh->zh_log))
580 return;
581
582 tx = dmu_tx_create(zilog->zl_os);
583 VERIFY(dmu_tx_assign(tx, TXG_WAIT) == 0);
584 dsl_dataset_dirty(dmu_objset_ds(zilog->zl_os), tx);
585 txg = dmu_tx_get_txg(tx);
586
587 mutex_enter(&zilog->zl_lock);
588
589 ASSERT3U(zilog->zl_destroy_txg, <, txg);
590 zilog->zl_destroy_txg = txg;
591 zilog->zl_keep_first = keep_first;
592
593 if (!list_is_empty(&zilog->zl_lwb_list)) {
594 ASSERT(zh->zh_claim_txg == 0);
595 VERIFY(!keep_first);
596 while ((lwb = list_head(&zilog->zl_lwb_list)) != NULL) {
597 list_remove(&zilog->zl_lwb_list, lwb);
598 if (lwb->lwb_buf != NULL)
599 zio_buf_free(lwb->lwb_buf, lwb->lwb_sz);
600 zio_free_zil(zilog->zl_spa, txg, &lwb->lwb_blk);
601 kmem_cache_free(zil_lwb_cache, lwb);
602 }
603 } else if (!keep_first) {
604 zil_destroy_sync(zilog, tx);
605 }
606 mutex_exit(&zilog->zl_lock);
607
608 dmu_tx_commit(tx);
609 }
610
611 void
612 zil_destroy_sync(zilog_t *zilog, dmu_tx_t *tx)
613 {
614 ASSERT(list_is_empty(&zilog->zl_lwb_list));
615 (void) zil_parse(zilog, zil_free_log_block,
616 zil_free_log_record, tx, zilog->zl_header->zh_claim_txg);
617 }
618
619 int
620 zil_claim(const char *osname, void *txarg)
621 {
622 dmu_tx_t *tx = txarg;
623 uint64_t first_txg = dmu_tx_get_txg(tx);
624 zilog_t *zilog;
625 zil_header_t *zh;
626 objset_t *os;
627 int error;
628
629 error = dmu_objset_own(osname, DMU_OST_ANY, B_FALSE, FTAG, &os);
630 if (error != 0) {
631 cmn_err(CE_WARN, "can't open objset for %s", osname);
632 return (0);
633 }
634
635 zilog = dmu_objset_zil(os);
636 zh = zil_header_in_syncing_context(zilog);
637
638 if (spa_get_log_state(zilog->zl_spa) == SPA_LOG_CLEAR) {
639 if (!BP_IS_HOLE(&zh->zh_log))
640 zio_free_zil(zilog->zl_spa, first_txg, &zh->zh_log);
641 BP_ZERO(&zh->zh_log);
642 dsl_dataset_dirty(dmu_objset_ds(os), tx);
643 dmu_objset_disown(os, FTAG);
644 return (0);
645 }
646
647 /*
648 * Claim all log blocks if we haven't already done so, and remember
649 * the highest claimed sequence number. This ensures that if we can
650 * read only part of the log now (e.g. due to a missing device),
651 * but we can read the entire log later, we will not try to replay
652 * or destroy beyond the last block we successfully claimed.
653 */
654 ASSERT3U(zh->zh_claim_txg, <=, first_txg);
655 if (zh->zh_claim_txg == 0 && !BP_IS_HOLE(&zh->zh_log)) {
656 (void) zil_parse(zilog, zil_claim_log_block,
657 zil_claim_log_record, tx, first_txg);
658 zh->zh_claim_txg = first_txg;
659 zh->zh_claim_blk_seq = zilog->zl_parse_blk_seq;
660 zh->zh_claim_lr_seq = zilog->zl_parse_lr_seq;
661 if (zilog->zl_parse_lr_count || zilog->zl_parse_blk_count > 1)
662 zh->zh_flags |= ZIL_REPLAY_NEEDED;
663 zh->zh_flags |= ZIL_CLAIM_LR_SEQ_VALID;
664 dsl_dataset_dirty(dmu_objset_ds(os), tx);
665 }
666
667 ASSERT3U(first_txg, ==, (spa_last_synced_txg(zilog->zl_spa) + 1));
668 dmu_objset_disown(os, FTAG);
669 return (0);
670 }
671
672 /*
673 * Check the log by walking the log chain.
674 * Checksum errors are ok as they indicate the end of the chain.
675 * Any other error (no device or read failure) returns an error.
676 */
677 int
678 zil_check_log_chain(const char *osname, void *tx)
679 {
680 zilog_t *zilog;
681 objset_t *os;
682 blkptr_t *bp;
683 int error;
684
685 ASSERT(tx == NULL);
686
687 error = dmu_objset_hold(osname, FTAG, &os);
688 if (error != 0) {
689 cmn_err(CE_WARN, "can't open objset for %s", osname);
690 return (0);
691 }
692
693 zilog = dmu_objset_zil(os);
694 bp = (blkptr_t *)&zilog->zl_header->zh_log;
695
696 /*
697 * Check the first block and determine if it's on a log device
698 * which may have been removed or faulted prior to loading this
699 * pool. If so, there's no point in checking the rest of the log
700 * as its content should have already been synced to the pool.
701 */
702 if (!BP_IS_HOLE(bp)) {
703 vdev_t *vd;
704 boolean_t valid = B_TRUE;
705
706 spa_config_enter(os->os_spa, SCL_STATE, FTAG, RW_READER);
707 vd = vdev_lookup_top(os->os_spa, DVA_GET_VDEV(&bp->blk_dva[0]));
708 if (vd->vdev_islog && vdev_is_dead(vd))
709 valid = vdev_log_state_valid(vd);
710 spa_config_exit(os->os_spa, SCL_STATE, FTAG);
711
712 if (!valid) {
713 dmu_objset_rele(os, FTAG);
714 return (0);
715 }
716 }
717
718 /*
719 * Because tx == NULL, zil_claim_log_block() will not actually claim
720 * any blocks, but just determine whether it is possible to do so.
721 * In addition to checking the log chain, zil_claim_log_block()
722 * will invoke zio_claim() with a done func of spa_claim_notify(),
723 * which will update spa_max_claim_txg. See spa_load() for details.
724 */
725 error = zil_parse(zilog, zil_claim_log_block, zil_claim_log_record, tx,
726 zilog->zl_header->zh_claim_txg ? -1ULL : spa_first_txg(os->os_spa));
727
728 dmu_objset_rele(os, FTAG);
729
730 return ((error == ECKSUM || error == ENOENT) ? 0 : error);
731 }
732
733 static int
734 zil_vdev_compare(const void *x1, const void *x2)
735 {
736 const uint64_t v1 = ((zil_vdev_node_t *)x1)->zv_vdev;
737 const uint64_t v2 = ((zil_vdev_node_t *)x2)->zv_vdev;
738
739 if (v1 < v2)
740 return (-1);
741 if (v1 > v2)
742 return (1);
743
744 return (0);
745 }
746
747 void
748 zil_add_block(zilog_t *zilog, const blkptr_t *bp)
749 {
750 avl_tree_t *t = &zilog->zl_vdev_tree;
751 avl_index_t where;
752 zil_vdev_node_t *zv, zvsearch;
753 int ndvas = BP_GET_NDVAS(bp);
754 int i;
755
756 if (zfs_nocacheflush)
757 return;
758
759 ASSERT(zilog->zl_writer);
760
761 /*
762 * Even though we're zl_writer, we still need a lock because the
763 * zl_get_data() callbacks may have dmu_sync() done callbacks
764 * that will run concurrently.
765 */
766 mutex_enter(&zilog->zl_vdev_lock);
767 for (i = 0; i < ndvas; i++) {
768 zvsearch.zv_vdev = DVA_GET_VDEV(&bp->blk_dva[i]);
769 if (avl_find(t, &zvsearch, &where) == NULL) {
770 zv = kmem_alloc(sizeof (*zv), KM_SLEEP);
771 zv->zv_vdev = zvsearch.zv_vdev;
772 avl_insert(t, zv, where);
773 }
774 }
775 mutex_exit(&zilog->zl_vdev_lock);
776 }
777
778 static void
779 zil_flush_vdevs(zilog_t *zilog)
780 {
781 spa_t *spa = zilog->zl_spa;
782 avl_tree_t *t = &zilog->zl_vdev_tree;
783 void *cookie = NULL;
784 zil_vdev_node_t *zv;
785 zio_t *zio;
786
787 ASSERT(zilog->zl_writer);
788
789 /*
790 * We don't need zl_vdev_lock here because we're the zl_writer,
791 * and all zl_get_data() callbacks are done.
792 */
793 if (avl_numnodes(t) == 0)
794 return;
795
796 spa_config_enter(spa, SCL_STATE, FTAG, RW_READER);
797
798 zio = zio_root(spa, NULL, NULL, ZIO_FLAG_CANFAIL);
799
800 while ((zv = avl_destroy_nodes(t, &cookie)) != NULL) {
801 vdev_t *vd = vdev_lookup_top(spa, zv->zv_vdev);
802 if (vd != NULL)
803 zio_flush(zio, vd);
804 kmem_free(zv, sizeof (*zv));
805 }
806
807 /*
808 * Wait for all the flushes to complete. Not all devices actually
809 * support the DKIOCFLUSHWRITECACHE ioctl, so it's OK if it fails.
810 */
811 (void) zio_wait(zio);
812
813 spa_config_exit(spa, SCL_STATE, FTAG);
814 }
815
816 /*
817 * Function called when a log block write completes
818 */
819 static void
820 zil_lwb_write_done(zio_t *zio)
821 {
822 lwb_t *lwb = zio->io_private;
823 zilog_t *zilog = lwb->lwb_zilog;
824 dmu_tx_t *tx = lwb->lwb_tx;
825
826 ASSERT(BP_GET_COMPRESS(zio->io_bp) == ZIO_COMPRESS_OFF);
827 ASSERT(BP_GET_TYPE(zio->io_bp) == DMU_OT_INTENT_LOG);
828 ASSERT(BP_GET_LEVEL(zio->io_bp) == 0);
829 ASSERT(BP_GET_BYTEORDER(zio->io_bp) == ZFS_HOST_BYTEORDER);
830 ASSERT(!BP_IS_GANG(zio->io_bp));
831 ASSERT(!BP_IS_HOLE(zio->io_bp));
832 ASSERT(zio->io_bp->blk_fill == 0);
833
834 /*
835 * Ensure the lwb buffer pointer is cleared before releasing
836 * the txg. If we have had an allocation failure and
837 * the txg is waiting to sync then we want want zil_sync()
838 * to remove the lwb so that it's not picked up as the next new
839 * one in zil_commit_writer(). zil_sync() will only remove
840 * the lwb if lwb_buf is null.
841 */
842 zio_buf_free(lwb->lwb_buf, lwb->lwb_sz);
843 mutex_enter(&zilog->zl_lock);
844 lwb->lwb_buf = NULL;
845 lwb->lwb_tx = NULL;
846 mutex_exit(&zilog->zl_lock);
847
848 /*
849 * Now that we've written this log block, we have a stable pointer
850 * to the next block in the chain, so it's OK to let the txg in
851 * which we allocated the next block sync.
852 */
853 dmu_tx_commit(tx);
854 }
855
856 /*
857 * Initialize the io for a log block.
858 */
859 static void
860 zil_lwb_write_init(zilog_t *zilog, lwb_t *lwb)
861 {
862 zbookmark_t zb;
863
864 SET_BOOKMARK(&zb, lwb->lwb_blk.blk_cksum.zc_word[ZIL_ZC_OBJSET],
865 ZB_ZIL_OBJECT, ZB_ZIL_LEVEL,
866 lwb->lwb_blk.blk_cksum.zc_word[ZIL_ZC_SEQ]);
867
868 if (zilog->zl_root_zio == NULL) {
869 zilog->zl_root_zio = zio_root(zilog->zl_spa, NULL, NULL,
870 ZIO_FLAG_CANFAIL);
871 }
872 if (lwb->lwb_zio == NULL) {
873 lwb->lwb_zio = zio_rewrite(zilog->zl_root_zio, zilog->zl_spa,
874 0, &lwb->lwb_blk, lwb->lwb_buf, BP_GET_LSIZE(&lwb->lwb_blk),
875 zil_lwb_write_done, lwb, ZIO_PRIORITY_SYNC_WRITE,
876 ZIO_FLAG_CANFAIL | ZIO_FLAG_DONT_PROPAGATE, &zb);
877 }
878 }
879
880 /*
881 * Define a limited set of intent log block sizes.
882 *
883 * These must be a multiple of 4KB. Note only the amount used (again
884 * aligned to 4KB) actually gets written. However, we can't always just
885 * allocate SPA_MAXBLOCKSIZE as the slog space could be exhausted.
886 */
887 uint64_t zil_block_buckets[] = {
888 4096, /* non TX_WRITE */
889 8192+4096, /* data base */
890 32*1024 + 4096, /* NFS writes */
891 UINT64_MAX
892 };
893
894 /*
895 * Use the slog as long as the logbias is 'latency' and the current commit size
896 * is less than the limit or the total list size is less than 2X the limit.
897 * Limit checking is disabled by setting zil_slog_limit to UINT64_MAX.
898 */
899 uint64_t zil_slog_limit = 1024 * 1024;
900 #define USE_SLOG(zilog) (((zilog)->zl_logbias == ZFS_LOGBIAS_LATENCY) && \
901 (((zilog)->zl_cur_used < zil_slog_limit) || \
902 ((zilog)->zl_itx_list_sz < (zil_slog_limit << 1))))
903
904 /*
905 * Start a log block write and advance to the next log block.
906 * Calls are serialized.
907 */
908 static lwb_t *
909 zil_lwb_write_start(zilog_t *zilog, lwb_t *lwb)
910 {
911 lwb_t *nlwb = NULL;
912 zil_chain_t *zilc;
913 spa_t *spa = zilog->zl_spa;
914 blkptr_t *bp;
915 dmu_tx_t *tx;
916 uint64_t txg;
917 uint64_t zil_blksz, wsz;
918 int i, error;
919
920 if (BP_GET_CHECKSUM(&lwb->lwb_blk) == ZIO_CHECKSUM_ZILOG2) {
921 zilc = (zil_chain_t *)lwb->lwb_buf;
922 bp = &zilc->zc_next_blk;
923 } else {
924 zilc = (zil_chain_t *)(lwb->lwb_buf + lwb->lwb_sz);
925 bp = &zilc->zc_next_blk;
926 }
927
928 ASSERT(lwb->lwb_nused <= lwb->lwb_sz);
929
930 /*
931 * Allocate the next block and save its address in this block
932 * before writing it in order to establish the log chain.
933 * Note that if the allocation of nlwb synced before we wrote
934 * the block that points at it (lwb), we'd leak it if we crashed.
935 * Therefore, we don't do dmu_tx_commit() until zil_lwb_write_done().
936 * We dirty the dataset to ensure that zil_sync() will be called
937 * to clean up in the event of allocation failure or I/O failure.
938 */
939 tx = dmu_tx_create(zilog->zl_os);
940 VERIFY(dmu_tx_assign(tx, TXG_WAIT) == 0);
941 dsl_dataset_dirty(dmu_objset_ds(zilog->zl_os), tx);
942 txg = dmu_tx_get_txg(tx);
943
944 lwb->lwb_tx = tx;
945
946 /*
947 * Log blocks are pre-allocated. Here we select the size of the next
948 * block, based on size used in the last block.
949 * - first find the smallest bucket that will fit the block from a
950 * limited set of block sizes. This is because it's faster to write
951 * blocks allocated from the same metaslab as they are adjacent or
952 * close.
953 * - next find the maximum from the new suggested size and an array of
954 * previous sizes. This lessens a picket fence effect of wrongly
955 * guesssing the size if we have a stream of say 2k, 64k, 2k, 64k
956 * requests.
957 *
958 * Note we only write what is used, but we can't just allocate
959 * the maximum block size because we can exhaust the available
960 * pool log space.
961 */
962 zil_blksz = zilog->zl_cur_used + sizeof (zil_chain_t);
963 for (i = 0; zil_blksz > zil_block_buckets[i]; i++)
964 continue;
965 zil_blksz = zil_block_buckets[i];
966 if (zil_blksz == UINT64_MAX)
967 zil_blksz = SPA_MAXBLOCKSIZE;
968 zilog->zl_prev_blks[zilog->zl_prev_rotor] = zil_blksz;
969 for (i = 0; i < ZIL_PREV_BLKS; i++)
970 zil_blksz = MAX(zil_blksz, zilog->zl_prev_blks[i]);
971 zilog->zl_prev_rotor = (zilog->zl_prev_rotor + 1) & (ZIL_PREV_BLKS - 1);
972
973 BP_ZERO(bp);
974 /* pass the old blkptr in order to spread log blocks across devs */
975 error = zio_alloc_zil(spa, txg, bp, &lwb->lwb_blk, zil_blksz,
976 USE_SLOG(zilog));
977 if (error == 0) {
978 ASSERT3U(bp->blk_birth, ==, txg);
979 bp->blk_cksum = lwb->lwb_blk.blk_cksum;
980 bp->blk_cksum.zc_word[ZIL_ZC_SEQ]++;
981
982 /*
983 * Allocate a new log write buffer (lwb).
984 */
985 nlwb = zil_alloc_lwb(zilog, bp, txg);
986
987 /* Record the block for later vdev flushing */
988 zil_add_block(zilog, &lwb->lwb_blk);
989 }
990
991 if (BP_GET_CHECKSUM(&lwb->lwb_blk) == ZIO_CHECKSUM_ZILOG2) {
992 /* For Slim ZIL only write what is used. */
993 wsz = P2ROUNDUP_TYPED(lwb->lwb_nused, ZIL_MIN_BLKSZ, uint64_t);
994 ASSERT3U(wsz, <=, lwb->lwb_sz);
995 zio_shrink(lwb->lwb_zio, wsz);
996
997 } else {
998 wsz = lwb->lwb_sz;
999 }
1000
1001 zilc->zc_pad = 0;
1002 zilc->zc_nused = lwb->lwb_nused;
1003 zilc->zc_eck.zec_cksum = lwb->lwb_blk.blk_cksum;
1004
1005 /*
1006 * clear unused data for security
1007 */
1008 bzero(lwb->lwb_buf + lwb->lwb_nused, wsz - lwb->lwb_nused);
1009
1010 zio_nowait(lwb->lwb_zio); /* Kick off the write for the old log block */
1011
1012 /*
1013 * If there was an allocation failure then nlwb will be null which
1014 * forces a txg_wait_synced().
1015 */
1016 return (nlwb);
1017 }
1018
1019 static lwb_t *
1020 zil_lwb_commit(zilog_t *zilog, itx_t *itx, lwb_t *lwb)
1021 {
1022 lr_t *lrc = &itx->itx_lr; /* common log record */
1023 lr_write_t *lrw = (lr_write_t *)lrc;
1024 char *lr_buf;
1025 uint64_t txg = lrc->lrc_txg;
1026 uint64_t reclen = lrc->lrc_reclen;
1027 uint64_t dlen = 0;
1028
1029 if (lwb == NULL)
1030 return (NULL);
1031
1032 ASSERT(lwb->lwb_buf != NULL);
1033 ASSERT(zilog_is_dirty(zilog) ||
1034 spa_freeze_txg(zilog->zl_spa) != UINT64_MAX);
1035
1036 if (lrc->lrc_txtype == TX_WRITE && itx->itx_wr_state == WR_NEED_COPY)
1037 dlen = P2ROUNDUP_TYPED(
1038 lrw->lr_length, sizeof (uint64_t), uint64_t);
1039
1040 zilog->zl_cur_used += (reclen + dlen);
1041
1042 zil_lwb_write_init(zilog, lwb);
1043
1044 /*
1045 * If this record won't fit in the current log block, start a new one.
1046 */
1047 if (lwb->lwb_nused + reclen + dlen > lwb->lwb_sz) {
1048 lwb = zil_lwb_write_start(zilog, lwb);
1049 if (lwb == NULL)
1050 return (NULL);
1051 zil_lwb_write_init(zilog, lwb);
1052 ASSERT(LWB_EMPTY(lwb));
1053 if (lwb->lwb_nused + reclen + dlen > lwb->lwb_sz) {
1054 txg_wait_synced(zilog->zl_dmu_pool, txg);
1055 return (lwb);
1056 }
1057 }
1058
1059 lr_buf = lwb->lwb_buf + lwb->lwb_nused;
1060 bcopy(lrc, lr_buf, reclen);
1061 lrc = (lr_t *)lr_buf;
1062 lrw = (lr_write_t *)lrc;
1063
1064 /*
1065 * If it's a write, fetch the data or get its blkptr as appropriate.
1066 */
1067 if (lrc->lrc_txtype == TX_WRITE) {
1068 if (txg > spa_freeze_txg(zilog->zl_spa))
1069 txg_wait_synced(zilog->zl_dmu_pool, txg);
1070 if (itx->itx_wr_state != WR_COPIED) {
1071 char *dbuf;
1072 int error;
1073
1074 if (dlen) {
1075 ASSERT(itx->itx_wr_state == WR_NEED_COPY);
1076 dbuf = lr_buf + reclen;
1077 lrw->lr_common.lrc_reclen += dlen;
1078 } else {
1079 ASSERT(itx->itx_wr_state == WR_INDIRECT);
1080 dbuf = NULL;
1081 }
1082 error = zilog->zl_get_data(
1083 itx->itx_private, lrw, dbuf, lwb->lwb_zio);
1084 if (error == EIO) {
1085 txg_wait_synced(zilog->zl_dmu_pool, txg);
1086 return (lwb);
1087 }
1088 if (error != 0) {
1089 ASSERT(error == ENOENT || error == EEXIST ||
1090 error == EALREADY);
1091 return (lwb);
1092 }
1093 }
1094 }
1095
1096 /*
1097 * We're actually making an entry, so update lrc_seq to be the
1098 * log record sequence number. Note that this is generally not
1099 * equal to the itx sequence number because not all transactions
1100 * are synchronous, and sometimes spa_sync() gets there first.
1101 */
1102 lrc->lrc_seq = ++zilog->zl_lr_seq; /* we are single threaded */
1103 lwb->lwb_nused += reclen + dlen;
1104 lwb->lwb_max_txg = MAX(lwb->lwb_max_txg, txg);
1105 ASSERT3U(lwb->lwb_nused, <=, lwb->lwb_sz);
1106 ASSERT0(P2PHASE(lwb->lwb_nused, sizeof (uint64_t)));
1107
1108 return (lwb);
1109 }
1110
1111 itx_t *
1112 zil_itx_create(uint64_t txtype, size_t lrsize)
1113 {
1114 itx_t *itx;
1115
1116 lrsize = P2ROUNDUP_TYPED(lrsize, sizeof (uint64_t), size_t);
1117
1118 itx = kmem_alloc(offsetof(itx_t, itx_lr) + lrsize, KM_SLEEP);
1119 itx->itx_lr.lrc_txtype = txtype;
1120 itx->itx_lr.lrc_reclen = lrsize;
1121 itx->itx_sod = lrsize; /* if write & WR_NEED_COPY will be increased */
1122 itx->itx_lr.lrc_seq = 0; /* defensive */
1123 itx->itx_sync = B_TRUE; /* default is synchronous */
1124
1125 return (itx);
1126 }
1127
1128 void
1129 zil_itx_destroy(itx_t *itx)
1130 {
1131 kmem_free(itx, offsetof(itx_t, itx_lr) + itx->itx_lr.lrc_reclen);
1132 }
1133
1134 /*
1135 * Free up the sync and async itxs. The itxs_t has already been detached
1136 * so no locks are needed.
1137 */
1138 static void
1139 zil_itxg_clean(itxs_t *itxs)
1140 {
1141 itx_t *itx;
1142 list_t *list;
1143 avl_tree_t *t;
1144 void *cookie;
1145 itx_async_node_t *ian;
1146
1147 list = &itxs->i_sync_list;
1148 while ((itx = list_head(list)) != NULL) {
1149 list_remove(list, itx);
1150 kmem_free(itx, offsetof(itx_t, itx_lr) +
1151 itx->itx_lr.lrc_reclen);
1152 }
1153
1154 cookie = NULL;
1155 t = &itxs->i_async_tree;
1156 while ((ian = avl_destroy_nodes(t, &cookie)) != NULL) {
1157 list = &ian->ia_list;
1158 while ((itx = list_head(list)) != NULL) {
1159 list_remove(list, itx);
1160 kmem_free(itx, offsetof(itx_t, itx_lr) +
1161 itx->itx_lr.lrc_reclen);
1162 }
1163 list_destroy(list);
1164 kmem_free(ian, sizeof (itx_async_node_t));
1165 }
1166 avl_destroy(t);
1167
1168 kmem_free(itxs, sizeof (itxs_t));
1169 }
1170
1171 static int
1172 zil_aitx_compare(const void *x1, const void *x2)
1173 {
1174 const uint64_t o1 = ((itx_async_node_t *)x1)->ia_foid;
1175 const uint64_t o2 = ((itx_async_node_t *)x2)->ia_foid;
1176
1177 if (o1 < o2)
1178 return (-1);
1179 if (o1 > o2)
1180 return (1);
1181
1182 return (0);
1183 }
1184
1185 /*
1186 * Remove all async itx with the given oid.
1187 */
1188 static void
1189 zil_remove_async(zilog_t *zilog, uint64_t oid)
1190 {
1191 uint64_t otxg, txg;
1192 itx_async_node_t *ian;
1193 avl_tree_t *t;
1194 avl_index_t where;
1195 list_t clean_list;
1196 itx_t *itx;
1197
1198 ASSERT(oid != 0);
1199 list_create(&clean_list, sizeof (itx_t), offsetof(itx_t, itx_node));
1200
1201 if (spa_freeze_txg(zilog->zl_spa) != UINT64_MAX) /* ziltest support */
1202 otxg = ZILTEST_TXG;
1203 else
1204 otxg = spa_last_synced_txg(zilog->zl_spa) + 1;
1205
1206 for (txg = otxg; txg < (otxg + TXG_CONCURRENT_STATES); txg++) {
1207 itxg_t *itxg = &zilog->zl_itxg[txg & TXG_MASK];
1208
1209 mutex_enter(&itxg->itxg_lock);
1210 if (itxg->itxg_txg != txg) {
1211 mutex_exit(&itxg->itxg_lock);
1212 continue;
1213 }
1214
1215 /*
1216 * Locate the object node and append its list.
1217 */
1218 t = &itxg->itxg_itxs->i_async_tree;
1219 ian = avl_find(t, &oid, &where);
1220 if (ian != NULL)
1221 list_move_tail(&clean_list, &ian->ia_list);
1222 mutex_exit(&itxg->itxg_lock);
1223 }
1224 while ((itx = list_head(&clean_list)) != NULL) {
1225 list_remove(&clean_list, itx);
1226 kmem_free(itx, offsetof(itx_t, itx_lr) +
1227 itx->itx_lr.lrc_reclen);
1228 }
1229 list_destroy(&clean_list);
1230 }
1231
1232 void
1233 zil_itx_assign(zilog_t *zilog, itx_t *itx, dmu_tx_t *tx)
1234 {
1235 uint64_t txg;
1236 itxg_t *itxg;
1237 itxs_t *itxs, *clean = NULL;
1238
1239 /*
1240 * Object ids can be re-instantiated in the next txg so
1241 * remove any async transactions to avoid future leaks.
1242 * This can happen if a fsync occurs on the re-instantiated
1243 * object for a WR_INDIRECT or WR_NEED_COPY write, which gets
1244 * the new file data and flushes a write record for the old object.
1245 */
1246 if ((itx->itx_lr.lrc_txtype & ~TX_CI) == TX_REMOVE)
1247 zil_remove_async(zilog, itx->itx_oid);
1248
1249 /*
1250 * Ensure the data of a renamed file is committed before the rename.
1251 */
1252 if ((itx->itx_lr.lrc_txtype & ~TX_CI) == TX_RENAME)
1253 zil_async_to_sync(zilog, itx->itx_oid);
1254
1255 if (spa_freeze_txg(zilog->zl_spa) != UINT64_MAX)
1256 txg = ZILTEST_TXG;
1257 else
1258 txg = dmu_tx_get_txg(tx);
1259
1260 itxg = &zilog->zl_itxg[txg & TXG_MASK];
1261 mutex_enter(&itxg->itxg_lock);
1262 itxs = itxg->itxg_itxs;
1263 if (itxg->itxg_txg != txg) {
1264 if (itxs != NULL) {
1265 /*
1266 * The zil_clean callback hasn't got around to cleaning
1267 * this itxg. Save the itxs for release below.
1268 * This should be rare.
1269 */
1270 atomic_add_64(&zilog->zl_itx_list_sz, -itxg->itxg_sod);
1271 itxg->itxg_sod = 0;
1272 clean = itxg->itxg_itxs;
1273 }
1274 ASSERT(itxg->itxg_sod == 0);
1275 itxg->itxg_txg = txg;
1276 itxs = itxg->itxg_itxs = kmem_zalloc(sizeof (itxs_t), KM_SLEEP);
1277
1278 list_create(&itxs->i_sync_list, sizeof (itx_t),
1279 offsetof(itx_t, itx_node));
1280 avl_create(&itxs->i_async_tree, zil_aitx_compare,
1281 sizeof (itx_async_node_t),
1282 offsetof(itx_async_node_t, ia_node));
1283 }
1284 if (itx->itx_sync) {
1285 list_insert_tail(&itxs->i_sync_list, itx);
1286 atomic_add_64(&zilog->zl_itx_list_sz, itx->itx_sod);
1287 itxg->itxg_sod += itx->itx_sod;
1288 } else {
1289 avl_tree_t *t = &itxs->i_async_tree;
1290 uint64_t foid = ((lr_ooo_t *)&itx->itx_lr)->lr_foid;
1291 itx_async_node_t *ian;
1292 avl_index_t where;
1293
1294 ian = avl_find(t, &foid, &where);
1295 if (ian == NULL) {
1296 ian = kmem_alloc(sizeof (itx_async_node_t), KM_SLEEP);
1297 list_create(&ian->ia_list, sizeof (itx_t),
1298 offsetof(itx_t, itx_node));
1299 ian->ia_foid = foid;
1300 avl_insert(t, ian, where);
1301 }
1302 list_insert_tail(&ian->ia_list, itx);
1303 }
1304
1305 itx->itx_lr.lrc_txg = dmu_tx_get_txg(tx);
1306 zilog_dirty(zilog, txg);
1307 mutex_exit(&itxg->itxg_lock);
1308
1309 /* Release the old itxs now we've dropped the lock */
1310 if (clean != NULL)
1311 zil_itxg_clean(clean);
1312 }
1313
1314 /*
1315 * If there are any in-memory intent log transactions which have now been
1316 * synced then start up a taskq to free them. We should only do this after we
1317 * have written out the uberblocks (i.e. txg has been comitted) so that
1318 * don't inadvertently clean out in-memory log records that would be required
1319 * by zil_commit().
1320 */
1321 void
1322 zil_clean(zilog_t *zilog, uint64_t synced_txg)
1323 {
1324 itxg_t *itxg = &zilog->zl_itxg[synced_txg & TXG_MASK];
1325 itxs_t *clean_me;
1326
1327 mutex_enter(&itxg->itxg_lock);
1328 if (itxg->itxg_itxs == NULL || itxg->itxg_txg == ZILTEST_TXG) {
1329 mutex_exit(&itxg->itxg_lock);
1330 return;
1331 }
1332 ASSERT3U(itxg->itxg_txg, <=, synced_txg);
1333 ASSERT(itxg->itxg_txg != 0);
1334 ASSERT(zilog->zl_clean_taskq != NULL);
1335 atomic_add_64(&zilog->zl_itx_list_sz, -itxg->itxg_sod);
1336 itxg->itxg_sod = 0;
1337 clean_me = itxg->itxg_itxs;
1338 itxg->itxg_itxs = NULL;
1339 itxg->itxg_txg = 0;
1340 mutex_exit(&itxg->itxg_lock);
1341 /*
1342 * Preferably start a task queue to free up the old itxs but
1343 * if taskq_dispatch can't allocate resources to do that then
1344 * free it in-line. This should be rare. Note, using TQ_SLEEP
1345 * created a bad performance problem.
1346 */
1347 if (taskq_dispatch(zilog->zl_clean_taskq,
1348 (void (*)(void *))zil_itxg_clean, clean_me, TQ_NOSLEEP) == NULL)
1349 zil_itxg_clean(clean_me);
1350 }
1351
1352 /*
1353 * Get the list of itxs to commit into zl_itx_commit_list.
1354 */
1355 static void
1356 zil_get_commit_list(zilog_t *zilog)
1357 {
1358 uint64_t otxg, txg;
1359 list_t *commit_list = &zilog->zl_itx_commit_list;
1360 uint64_t push_sod = 0;
1361
1362 if (spa_freeze_txg(zilog->zl_spa) != UINT64_MAX) /* ziltest support */
1363 otxg = ZILTEST_TXG;
1364 else
1365 otxg = spa_last_synced_txg(zilog->zl_spa) + 1;
1366
1367 for (txg = otxg; txg < (otxg + TXG_CONCURRENT_STATES); txg++) {
1368 itxg_t *itxg = &zilog->zl_itxg[txg & TXG_MASK];
1369
1370 mutex_enter(&itxg->itxg_lock);
1371 if (itxg->itxg_txg != txg) {
1372 mutex_exit(&itxg->itxg_lock);
1373 continue;
1374 }
1375
1376 list_move_tail(commit_list, &itxg->itxg_itxs->i_sync_list);
1377 push_sod += itxg->itxg_sod;
1378 itxg->itxg_sod = 0;
1379
1380 mutex_exit(&itxg->itxg_lock);
1381 }
1382 atomic_add_64(&zilog->zl_itx_list_sz, -push_sod);
1383 }
1384
1385 /*
1386 * Move the async itxs for a specified object to commit into sync lists.
1387 */
1388 static void
1389 zil_async_to_sync(zilog_t *zilog, uint64_t foid)
1390 {
1391 uint64_t otxg, txg;
1392 itx_async_node_t *ian;
1393 avl_tree_t *t;
1394 avl_index_t where;
1395
1396 if (spa_freeze_txg(zilog->zl_spa) != UINT64_MAX) /* ziltest support */
1397 otxg = ZILTEST_TXG;
1398 else
1399 otxg = spa_last_synced_txg(zilog->zl_spa) + 1;
1400
1401 for (txg = otxg; txg < (otxg + TXG_CONCURRENT_STATES); txg++) {
1402 itxg_t *itxg = &zilog->zl_itxg[txg & TXG_MASK];
1403
1404 mutex_enter(&itxg->itxg_lock);
1405 if (itxg->itxg_txg != txg) {
1406 mutex_exit(&itxg->itxg_lock);
1407 continue;
1408 }
1409
1410 /*
1411 * If a foid is specified then find that node and append its
1412 * list. Otherwise walk the tree appending all the lists
1413 * to the sync list. We add to the end rather than the
1414 * beginning to ensure the create has happened.
1415 */
1416 t = &itxg->itxg_itxs->i_async_tree;
1417 if (foid != 0) {
1418 ian = avl_find(t, &foid, &where);
1419 if (ian != NULL) {
1420 list_move_tail(&itxg->itxg_itxs->i_sync_list,
1421 &ian->ia_list);
1422 }
1423 } else {
1424 void *cookie = NULL;
1425
1426 while ((ian = avl_destroy_nodes(t, &cookie)) != NULL) {
1427 list_move_tail(&itxg->itxg_itxs->i_sync_list,
1428 &ian->ia_list);
1429 list_destroy(&ian->ia_list);
1430 kmem_free(ian, sizeof (itx_async_node_t));
1431 }
1432 }
1433 mutex_exit(&itxg->itxg_lock);
1434 }
1435 }
1436
1437 static void
1438 zil_commit_writer(zilog_t *zilog)
1439 {
1440 uint64_t txg;
1441 itx_t *itx;
1442 lwb_t *lwb;
1443 spa_t *spa = zilog->zl_spa;
1444 int error = 0;
1445
1446 ASSERT(zilog->zl_root_zio == NULL);
1447
1448 mutex_exit(&zilog->zl_lock);
1449
1450 zil_get_commit_list(zilog);
1451
1452 /*
1453 * Return if there's nothing to commit before we dirty the fs by
1454 * calling zil_create().
1455 */
1456 if (list_head(&zilog->zl_itx_commit_list) == NULL) {
1457 mutex_enter(&zilog->zl_lock);
1458 return;
1459 }
1460
1461 if (zilog->zl_suspend) {
1462 lwb = NULL;
1463 } else {
1464 lwb = list_tail(&zilog->zl_lwb_list);
1465 if (lwb == NULL)
1466 lwb = zil_create(zilog);
1467 }
1468
1469 DTRACE_PROBE1(zil__cw1, zilog_t *, zilog);
1470 while (itx = list_head(&zilog->zl_itx_commit_list)) {
1471 txg = itx->itx_lr.lrc_txg;
1472 ASSERT(txg);
1473
1474 if (txg > spa_last_synced_txg(spa) || txg > spa_freeze_txg(spa))
1475 lwb = zil_lwb_commit(zilog, itx, lwb);
1476 list_remove(&zilog->zl_itx_commit_list, itx);
1477 kmem_free(itx, offsetof(itx_t, itx_lr)
1478 + itx->itx_lr.lrc_reclen);
1479 }
1480 DTRACE_PROBE1(zil__cw2, zilog_t *, zilog);
1481
1482 /* write the last block out */
1483 if (lwb != NULL && lwb->lwb_zio != NULL)
1484 lwb = zil_lwb_write_start(zilog, lwb);
1485
1486 zilog->zl_cur_used = 0;
1487
1488 /*
1489 * Wait if necessary for the log blocks to be on stable storage.
1490 */
1491 if (zilog->zl_root_zio) {
1492 error = zio_wait(zilog->zl_root_zio);
1493 zilog->zl_root_zio = NULL;
1494 zil_flush_vdevs(zilog);
1495 }
1496
1497 if (error || lwb == NULL)
1498 txg_wait_synced(zilog->zl_dmu_pool, 0);
1499
1500 mutex_enter(&zilog->zl_lock);
1501
1502 /*
1503 * Remember the highest committed log sequence number for ztest.
1504 * We only update this value when all the log writes succeeded,
1505 * because ztest wants to ASSERT that it got the whole log chain.
1506 */
1507 if (error == 0 && lwb != NULL)
1508 zilog->zl_commit_lr_seq = zilog->zl_lr_seq;
1509 }
1510
1511 /*
1512 * Commit zfs transactions to stable storage.
1513 * If foid is 0 push out all transactions, otherwise push only those
1514 * for that object or might reference that object.
1515 *
1516 * itxs are committed in batches. In a heavily stressed zil there will be
1517 * a commit writer thread who is writing out a bunch of itxs to the log
1518 * for a set of committing threads (cthreads) in the same batch as the writer.
1519 * Those cthreads are all waiting on the same cv for that batch.
1520 *
1521 * There will also be a different and growing batch of threads that are
1522 * waiting to commit (qthreads). When the committing batch completes
1523 * a transition occurs such that the cthreads exit and the qthreads become
1524 * cthreads. One of the new cthreads becomes the writer thread for the
1525 * batch. Any new threads arriving become new qthreads.
1526 *
1527 * Only 2 condition variables are needed and there's no transition
1528 * between the two cvs needed. They just flip-flop between qthreads
1529 * and cthreads.
1530 *
1531 * Using this scheme we can efficiently wakeup up only those threads
1532 * that have been committed.
1533 */
1534 void
1535 zil_commit(zilog_t *zilog, uint64_t foid)
1536 {
1537 uint64_t mybatch;
1538
1539 if (zilog->zl_sync == ZFS_SYNC_DISABLED)
1540 return;
1541
1542 /* move the async itxs for the foid to the sync queues */
1543 zil_async_to_sync(zilog, foid);
1544
1545 mutex_enter(&zilog->zl_lock);
1546 mybatch = zilog->zl_next_batch;
1547 while (zilog->zl_writer) {
1548 cv_wait(&zilog->zl_cv_batch[mybatch & 1], &zilog->zl_lock);
1549 if (mybatch <= zilog->zl_com_batch) {
1550 mutex_exit(&zilog->zl_lock);
1551 return;
1552 }
1553 }
1554
1555 zilog->zl_next_batch++;
1556 zilog->zl_writer = B_TRUE;
1557 zil_commit_writer(zilog);
1558 zilog->zl_com_batch = mybatch;
1559 zilog->zl_writer = B_FALSE;
1560 mutex_exit(&zilog->zl_lock);
1561
1562 /* wake up one thread to become the next writer */
1563 cv_signal(&zilog->zl_cv_batch[(mybatch+1) & 1]);
1564
1565 /* wake up all threads waiting for this batch to be committed */
1566 cv_broadcast(&zilog->zl_cv_batch[mybatch & 1]);
1567 }
1568
1569 /*
1570 * Called in syncing context to free committed log blocks and update log header.
1571 */
1572 void
1573 zil_sync(zilog_t *zilog, dmu_tx_t *tx)
1574 {
1575 zil_header_t *zh = zil_header_in_syncing_context(zilog);
1576 uint64_t txg = dmu_tx_get_txg(tx);
1577 spa_t *spa = zilog->zl_spa;
1578 uint64_t *replayed_seq = &zilog->zl_replayed_seq[txg & TXG_MASK];
1579 lwb_t *lwb;
1580
1581 /*
1582 * We don't zero out zl_destroy_txg, so make sure we don't try
1583 * to destroy it twice.
1584 */
1585 if (spa_sync_pass(spa) != 1)
1586 return;
1587
1588 mutex_enter(&zilog->zl_lock);
1589
1590 ASSERT(zilog->zl_stop_sync == 0);
1591
1592 if (*replayed_seq != 0) {
1593 ASSERT(zh->zh_replay_seq < *replayed_seq);
1594 zh->zh_replay_seq = *replayed_seq;
1595 *replayed_seq = 0;
1596 }
1597
1598 if (zilog->zl_destroy_txg == txg) {
1599 blkptr_t blk = zh->zh_log;
1600
1601 ASSERT(list_head(&zilog->zl_lwb_list) == NULL);
1602
1603 bzero(zh, sizeof (zil_header_t));
1604 bzero(zilog->zl_replayed_seq, sizeof (zilog->zl_replayed_seq));
1605
1606 if (zilog->zl_keep_first) {
1607 /*
1608 * If this block was part of log chain that couldn't
1609 * be claimed because a device was missing during
1610 * zil_claim(), but that device later returns,
1611 * then this block could erroneously appear valid.
1612 * To guard against this, assign a new GUID to the new
1613 * log chain so it doesn't matter what blk points to.
1614 */
1615 zil_init_log_chain(zilog, &blk);
1616 zh->zh_log = blk;
1617 }
1618 }
1619
1620 while ((lwb = list_head(&zilog->zl_lwb_list)) != NULL) {
1621 zh->zh_log = lwb->lwb_blk;
1622 if (lwb->lwb_buf != NULL || lwb->lwb_max_txg > txg)
1623 break;
1624 list_remove(&zilog->zl_lwb_list, lwb);
1625 zio_free_zil(spa, txg, &lwb->lwb_blk);
1626 kmem_cache_free(zil_lwb_cache, lwb);
1627
1628 /*
1629 * If we don't have anything left in the lwb list then
1630 * we've had an allocation failure and we need to zero
1631 * out the zil_header blkptr so that we don't end
1632 * up freeing the same block twice.
1633 */
1634 if (list_head(&zilog->zl_lwb_list) == NULL)
1635 BP_ZERO(&zh->zh_log);
1636 }
1637 mutex_exit(&zilog->zl_lock);
1638 }
1639
1640 void
1641 zil_init(void)
1642 {
1643 zil_lwb_cache = kmem_cache_create("zil_lwb_cache",
1644 sizeof (struct lwb), 0, NULL, NULL, NULL, NULL, NULL, 0);
1645 }
1646
1647 void
1648 zil_fini(void)
1649 {
1650 kmem_cache_destroy(zil_lwb_cache);
1651 }
1652
1653 void
1654 zil_set_sync(zilog_t *zilog, uint64_t sync)
1655 {
1656 zilog->zl_sync = sync;
1657 }
1658
1659 void
1660 zil_set_logbias(zilog_t *zilog, uint64_t logbias)
1661 {
1662 zilog->zl_logbias = logbias;
1663 }
1664
1665 zilog_t *
1666 zil_alloc(objset_t *os, zil_header_t *zh_phys)
1667 {
1668 zilog_t *zilog;
1669
1670 zilog = kmem_zalloc(sizeof (zilog_t), KM_SLEEP);
1671
1672 zilog->zl_header = zh_phys;
1673 zilog->zl_os = os;
1674 zilog->zl_spa = dmu_objset_spa(os);
1675 zilog->zl_dmu_pool = dmu_objset_pool(os);
1676 zilog->zl_destroy_txg = TXG_INITIAL - 1;
1677 zilog->zl_logbias = dmu_objset_logbias(os);
1678 zilog->zl_sync = dmu_objset_syncprop(os);
1679 zilog->zl_next_batch = 1;
1680
1681 mutex_init(&zilog->zl_lock, NULL, MUTEX_DEFAULT, NULL);
1682
1683 for (int i = 0; i < TXG_SIZE; i++) {
1684 mutex_init(&zilog->zl_itxg[i].itxg_lock, NULL,
1685 MUTEX_DEFAULT, NULL);
1686 }
1687
1688 list_create(&zilog->zl_lwb_list, sizeof (lwb_t),
1689 offsetof(lwb_t, lwb_node));
1690
1691 list_create(&zilog->zl_itx_commit_list, sizeof (itx_t),
1692 offsetof(itx_t, itx_node));
1693
1694 mutex_init(&zilog->zl_vdev_lock, NULL, MUTEX_DEFAULT, NULL);
1695
1696 avl_create(&zilog->zl_vdev_tree, zil_vdev_compare,
1697 sizeof (zil_vdev_node_t), offsetof(zil_vdev_node_t, zv_node));
1698
1699 cv_init(&zilog->zl_cv_writer, NULL, CV_DEFAULT, NULL);
1700 cv_init(&zilog->zl_cv_suspend, NULL, CV_DEFAULT, NULL);
1701 cv_init(&zilog->zl_cv_batch[0], NULL, CV_DEFAULT, NULL);
1702 cv_init(&zilog->zl_cv_batch[1], NULL, CV_DEFAULT, NULL);
1703
1704 return (zilog);
1705 }
1706
1707 void
1708 zil_free(zilog_t *zilog)
1709 {
1710 zilog->zl_stop_sync = 1;
1711
1712 ASSERT0(zilog->zl_suspend);
1713 ASSERT0(zilog->zl_suspending);
1714
1715 ASSERT(list_is_empty(&zilog->zl_lwb_list));
1716 list_destroy(&zilog->zl_lwb_list);
1717
1718 avl_destroy(&zilog->zl_vdev_tree);
1719 mutex_destroy(&zilog->zl_vdev_lock);
1720
1721 ASSERT(list_is_empty(&zilog->zl_itx_commit_list));
1722 list_destroy(&zilog->zl_itx_commit_list);
1723
1724 for (int i = 0; i < TXG_SIZE; i++) {
1725 /*
1726 * It's possible for an itx to be generated that doesn't dirty
1727 * a txg (e.g. ztest TX_TRUNCATE). So there's no zil_clean()
1728 * callback to remove the entry. We remove those here.
1729 *
1730 * Also free up the ziltest itxs.
1731 */
1732 if (zilog->zl_itxg[i].itxg_itxs)
1733 zil_itxg_clean(zilog->zl_itxg[i].itxg_itxs);
1734 mutex_destroy(&zilog->zl_itxg[i].itxg_lock);
1735 }
1736
1737 mutex_destroy(&zilog->zl_lock);
1738
1739 cv_destroy(&zilog->zl_cv_writer);
1740 cv_destroy(&zilog->zl_cv_suspend);
1741 cv_destroy(&zilog->zl_cv_batch[0]);
1742 cv_destroy(&zilog->zl_cv_batch[1]);
1743
1744 kmem_free(zilog, sizeof (zilog_t));
1745 }
1746
1747 /*
1748 * Open an intent log.
1749 */
1750 zilog_t *
1751 zil_open(objset_t *os, zil_get_data_t *get_data)
1752 {
1753 zilog_t *zilog = dmu_objset_zil(os);
1754
1755 ASSERT(zilog->zl_clean_taskq == NULL);
1756 ASSERT(zilog->zl_get_data == NULL);
1757 ASSERT(list_is_empty(&zilog->zl_lwb_list));
1758
1759 zilog->zl_get_data = get_data;
1760 zilog->zl_clean_taskq = taskq_create("zil_clean", 1, minclsyspri,
1761 2, 2, TASKQ_PREPOPULATE);
1762
1763 return (zilog);
1764 }
1765
1766 /*
1767 * Close an intent log.
1768 */
1769 void
1770 zil_close(zilog_t *zilog)
1771 {
1772 lwb_t *lwb;
1773 uint64_t txg = 0;
1774
1775 zil_commit(zilog, 0); /* commit all itx */
1776
1777 /*
1778 * The lwb_max_txg for the stubby lwb will reflect the last activity
1779 * for the zil. After a txg_wait_synced() on the txg we know all the
1780 * callbacks have occurred that may clean the zil. Only then can we
1781 * destroy the zl_clean_taskq.
1782 */
1783 mutex_enter(&zilog->zl_lock);
1784 lwb = list_tail(&zilog->zl_lwb_list);
1785 if (lwb != NULL)
1786 txg = lwb->lwb_max_txg;
1787 mutex_exit(&zilog->zl_lock);
1788 if (txg)
1789 txg_wait_synced(zilog->zl_dmu_pool, txg);
1790 ASSERT(!zilog_is_dirty(zilog));
1791
1792 taskq_destroy(zilog->zl_clean_taskq);
1793 zilog->zl_clean_taskq = NULL;
1794 zilog->zl_get_data = NULL;
1795
1796 /*
1797 * We should have only one LWB left on the list; remove it now.
1798 */
1799 mutex_enter(&zilog->zl_lock);
1800 lwb = list_head(&zilog->zl_lwb_list);
1801 if (lwb != NULL) {
1802 ASSERT(lwb == list_tail(&zilog->zl_lwb_list));
1803 list_remove(&zilog->zl_lwb_list, lwb);
1804 zio_buf_free(lwb->lwb_buf, lwb->lwb_sz);
1805 kmem_cache_free(zil_lwb_cache, lwb);
1806 }
1807 mutex_exit(&zilog->zl_lock);
1808 }
1809
1810 static char *suspend_tag = "zil suspending";
1811
1812 /*
1813 * Suspend an intent log. While in suspended mode, we still honor
1814 * synchronous semantics, but we rely on txg_wait_synced() to do it.
1815 * On old version pools, we suspend the log briefly when taking a
1816 * snapshot so that it will have an empty intent log.
1817 *
1818 * Long holds are not really intended to be used the way we do here --
1819 * held for such a short time. A concurrent caller of dsl_dataset_long_held()
1820 * could fail. Therefore we take pains to only put a long hold if it is
1821 * actually necessary. Fortunately, it will only be necessary if the
1822 * objset is currently mounted (or the ZVOL equivalent). In that case it
1823 * will already have a long hold, so we are not really making things any worse.
1824 *
1825 * Ideally, we would locate the existing long-holder (i.e. the zfsvfs_t or
1826 * zvol_state_t), and use their mechanism to prevent their hold from being
1827 * dropped (e.g. VFS_HOLD()). However, that would be even more pain for
1828 * very little gain.
1829 *
1830 * if cookiep == NULL, this does both the suspend & resume.
1831 * Otherwise, it returns with the dataset "long held", and the cookie
1832 * should be passed into zil_resume().
1833 */
1834 int
1835 zil_suspend(const char *osname, void **cookiep)
1836 {
1837 objset_t *os;
1838 zilog_t *zilog;
1839 const zil_header_t *zh;
1840 int error;
1841
1842 error = dmu_objset_hold(osname, suspend_tag, &os);
1843 if (error != 0)
1844 return (error);
1845 zilog = dmu_objset_zil(os);
1846
1847 mutex_enter(&zilog->zl_lock);
1848 zh = zilog->zl_header;
1849
1850 if (zh->zh_flags & ZIL_REPLAY_NEEDED) { /* unplayed log */
1851 mutex_exit(&zilog->zl_lock);
1852 dmu_objset_rele(os, suspend_tag);
1853 return (SET_ERROR(EBUSY));
1854 }
1855
1856 /*
1857 * Don't put a long hold in the cases where we can avoid it. This
1858 * is when there is no cookie so we are doing a suspend & resume
1859 * (i.e. called from zil_vdev_offline()), and there's nothing to do
1860 * for the suspend because it's already suspended, or there's no ZIL.
1861 */
1862 if (cookiep == NULL && !zilog->zl_suspending &&
1863 (zilog->zl_suspend > 0 || BP_IS_HOLE(&zh->zh_log))) {
1864 mutex_exit(&zilog->zl_lock);
1865 dmu_objset_rele(os, suspend_tag);
1866 return (0);
1867 }
1868
1869 dsl_dataset_long_hold(dmu_objset_ds(os), suspend_tag);
1870 dsl_pool_rele(dmu_objset_pool(os), suspend_tag);
1871
1872 zilog->zl_suspend++;
1873
1874 if (zilog->zl_suspend > 1) {
1875 /*
1876 * Someone else is already suspending it.
1877 * Just wait for them to finish.
1878 */
1879
1880 while (zilog->zl_suspending)
1881 cv_wait(&zilog->zl_cv_suspend, &zilog->zl_lock);
1882 mutex_exit(&zilog->zl_lock);
1883
1884 if (cookiep == NULL)
1885 zil_resume(os);
1886 else
1887 *cookiep = os;
1888 return (0);
1889 }
1890
1891 /*
1892 * If there is no pointer to an on-disk block, this ZIL must not
1893 * be active (e.g. filesystem not mounted), so there's nothing
1894 * to clean up.
1895 */
1896 if (BP_IS_HOLE(&zh->zh_log)) {
1897 ASSERT(cookiep != NULL); /* fast path already handled */
1898
1899 *cookiep = os;
1900 mutex_exit(&zilog->zl_lock);
1901 return (0);
1902 }
1903
1904 zilog->zl_suspending = B_TRUE;
1905 mutex_exit(&zilog->zl_lock);
1906
1907 zil_commit(zilog, 0);
1908
1909 zil_destroy(zilog, B_FALSE);
1910
1911 mutex_enter(&zilog->zl_lock);
1912 zilog->zl_suspending = B_FALSE;
1913 cv_broadcast(&zilog->zl_cv_suspend);
1914 mutex_exit(&zilog->zl_lock);
1915
1916 if (cookiep == NULL)
1917 zil_resume(os);
1918 else
1919 *cookiep = os;
1920 return (0);
1921 }
1922
1923 void
1924 zil_resume(void *cookie)
1925 {
1926 objset_t *os = cookie;
1927 zilog_t *zilog = dmu_objset_zil(os);
1928
1929 mutex_enter(&zilog->zl_lock);
1930 ASSERT(zilog->zl_suspend != 0);
1931 zilog->zl_suspend--;
1932 mutex_exit(&zilog->zl_lock);
1933 dsl_dataset_long_rele(dmu_objset_ds(os), suspend_tag);
1934 dsl_dataset_rele(dmu_objset_ds(os), suspend_tag);
1935 }
1936
1937 typedef struct zil_replay_arg {
1938 zil_replay_func_t **zr_replay;
1939 void *zr_arg;
1940 boolean_t zr_byteswap;
1941 char *zr_lr;
1942 } zil_replay_arg_t;
1943
1944 static int
1945 zil_replay_error(zilog_t *zilog, lr_t *lr, int error)
1946 {
1947 char name[MAXNAMELEN];
1948
1949 zilog->zl_replaying_seq--; /* didn't actually replay this one */
1950
1951 dmu_objset_name(zilog->zl_os, name);
1952
1953 cmn_err(CE_WARN, "ZFS replay transaction error %d, "
1954 "dataset %s, seq 0x%llx, txtype %llu %s\n", error, name,
1955 (u_longlong_t)lr->lrc_seq,
1956 (u_longlong_t)(lr->lrc_txtype & ~TX_CI),
1957 (lr->lrc_txtype & TX_CI) ? "CI" : "");
1958
1959 return (error);
1960 }
1961
1962 static int
1963 zil_replay_log_record(zilog_t *zilog, lr_t *lr, void *zra, uint64_t claim_txg)
1964 {
1965 zil_replay_arg_t *zr = zra;
1966 const zil_header_t *zh = zilog->zl_header;
1967 uint64_t reclen = lr->lrc_reclen;
1968 uint64_t txtype = lr->lrc_txtype;
1969 int error = 0;
1970
1971 zilog->zl_replaying_seq = lr->lrc_seq;
1972
1973 if (lr->lrc_seq <= zh->zh_replay_seq) /* already replayed */
1974 return (0);
1975
1976 if (lr->lrc_txg < claim_txg) /* already committed */
1977 return (0);
1978
1979 /* Strip case-insensitive bit, still present in log record */
1980 txtype &= ~TX_CI;
1981
1982 if (txtype == 0 || txtype >= TX_MAX_TYPE)
1983 return (zil_replay_error(zilog, lr, EINVAL));
1984
1985 /*
1986 * If this record type can be logged out of order, the object
1987 * (lr_foid) may no longer exist. That's legitimate, not an error.
1988 */
1989 if (TX_OOO(txtype)) {
1990 error = dmu_object_info(zilog->zl_os,
1991 ((lr_ooo_t *)lr)->lr_foid, NULL);
1992 if (error == ENOENT || error == EEXIST)
1993 return (0);
1994 }
1995
1996 /*
1997 * Make a copy of the data so we can revise and extend it.
1998 */
1999 bcopy(lr, zr->zr_lr, reclen);
2000
2001 /*
2002 * If this is a TX_WRITE with a blkptr, suck in the data.
2003 */
2004 if (txtype == TX_WRITE && reclen == sizeof (lr_write_t)) {
2005 error = zil_read_log_data(zilog, (lr_write_t *)lr,
2006 zr->zr_lr + reclen);
2007 if (error != 0)
2008 return (zil_replay_error(zilog, lr, error));
2009 }
2010
2011 /*
2012 * The log block containing this lr may have been byteswapped
2013 * so that we can easily examine common fields like lrc_txtype.
2014 * However, the log is a mix of different record types, and only the
2015 * replay vectors know how to byteswap their records. Therefore, if
2016 * the lr was byteswapped, undo it before invoking the replay vector.
2017 */
2018 if (zr->zr_byteswap)
2019 byteswap_uint64_array(zr->zr_lr, reclen);
2020
2021 /*
2022 * We must now do two things atomically: replay this log record,
2023 * and update the log header sequence number to reflect the fact that
2024 * we did so. At the end of each replay function the sequence number
2025 * is updated if we are in replay mode.
2026 */
2027 error = zr->zr_replay[txtype](zr->zr_arg, zr->zr_lr, zr->zr_byteswap);
2028 if (error != 0) {
2029 /*
2030 * The DMU's dnode layer doesn't see removes until the txg
2031 * commits, so a subsequent claim can spuriously fail with
2032 * EEXIST. So if we receive any error we try syncing out
2033 * any removes then retry the transaction. Note that we
2034 * specify B_FALSE for byteswap now, so we don't do it twice.
2035 */
2036 txg_wait_synced(spa_get_dsl(zilog->zl_spa), 0);
2037 error = zr->zr_replay[txtype](zr->zr_arg, zr->zr_lr, B_FALSE);
2038 if (error != 0)
2039 return (zil_replay_error(zilog, lr, error));
2040 }
2041 return (0);
2042 }
2043
2044 /* ARGSUSED */
2045 static int
2046 zil_incr_blks(zilog_t *zilog, blkptr_t *bp, void *arg, uint64_t claim_txg)
2047 {
2048 zilog->zl_replay_blks++;
2049
2050 return (0);
2051 }
2052
2053 /*
2054 * If this dataset has a non-empty intent log, replay it and destroy it.
2055 */
2056 void
2057 zil_replay(objset_t *os, void *arg, zil_replay_func_t *replay_func[TX_MAX_TYPE])
2058 {
2059 zilog_t *zilog = dmu_objset_zil(os);
2060 const zil_header_t *zh = zilog->zl_header;
2061 zil_replay_arg_t zr;
2062
2063 if ((zh->zh_flags & ZIL_REPLAY_NEEDED) == 0) {
2064 zil_destroy(zilog, B_TRUE);
2065 return;
2066 }
2067
2068 zr.zr_replay = replay_func;
2069 zr.zr_arg = arg;
2070 zr.zr_byteswap = BP_SHOULD_BYTESWAP(&zh->zh_log);
2071 zr.zr_lr = kmem_alloc(2 * SPA_MAXBLOCKSIZE, KM_SLEEP);
2072
2073 /*
2074 * Wait for in-progress removes to sync before starting replay.
2075 */
2076 txg_wait_synced(zilog->zl_dmu_pool, 0);
2077
2078 zilog->zl_replay = B_TRUE;
2079 zilog->zl_replay_time = ddi_get_lbolt();
2080 ASSERT(zilog->zl_replay_blks == 0);
2081 (void) zil_parse(zilog, zil_incr_blks, zil_replay_log_record, &zr,
2082 zh->zh_claim_txg);
2083 kmem_free(zr.zr_lr, 2 * SPA_MAXBLOCKSIZE);
2084
2085 zil_destroy(zilog, B_FALSE);
2086 txg_wait_synced(zilog->zl_dmu_pool, zilog->zl_destroy_txg);
2087 zilog->zl_replay = B_FALSE;
2088 }
2089
2090 boolean_t
2091 zil_replaying(zilog_t *zilog, dmu_tx_t *tx)
2092 {
2093 if (zilog->zl_sync == ZFS_SYNC_DISABLED)
2094 return (B_TRUE);
2095
2096 if (zilog->zl_replay) {
2097 dsl_dataset_dirty(dmu_objset_ds(zilog->zl_os), tx);
2098 zilog->zl_replayed_seq[dmu_tx_get_txg(tx) & TXG_MASK] =
2099 zilog->zl_replaying_seq;
2100 return (B_TRUE);
2101 }
2102
2103 return (B_FALSE);
2104 }
2105
2106 /* ARGSUSED */
2107 int
2108 zil_vdev_offline(const char *osname, void *arg)
2109 {
2110 int error;
2111
2112 error = zil_suspend(osname, NULL);
2113 if (error != 0)
2114 return (SET_ERROR(EEXIST));
2115 return (0);
2116 }