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) 2011, 2018 by Delphix. All rights reserved. 24 * Copyright (c) 2014 Integros [integros.com] 25 */ 26 27/* Portions Copyright 2010 Robert Milkowski */ 28 29#include <sys/zfs_context.h> 30#include <sys/spa.h> 31#include <sys/spa_impl.h> 32#include <sys/dmu.h> 33#include <sys/zap.h> 34#include <sys/arc.h> 35#include <sys/stat.h> 36#include <sys/resource.h> 37#include <sys/zil.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/abd.h> 44 45/* 46 * The ZFS Intent Log (ZIL) saves "transaction records" (itxs) of system 47 * calls that change the file system. Each itx has enough information to 48 * be able to replay them after a system crash, power loss, or 49 * equivalent failure mode. These are stored in memory until either: 50 * 51 * 1. they are committed to the pool by the DMU transaction group 52 * (txg), at which point they can be discarded; or 53 * 2. they are committed to the on-disk ZIL for the dataset being 54 * modified (e.g. due to an fsync, O_DSYNC, or other synchronous 55 * requirement). 56 * 57 * In the event of a crash or power loss, the itxs contained by each 58 * dataset's on-disk ZIL will be replayed when that dataset is first 59 * instantianted (e.g. if the dataset is a normal fileystem, when it is 60 * first mounted). 61 * 62 * As hinted at above, there is one ZIL per dataset (both the in-memory 63 * representation, and the on-disk representation). The on-disk format 64 * consists of 3 parts: 65 * 66 * - a single, per-dataset, ZIL header; which points to a chain of 67 * - zero or more ZIL blocks; each of which contains 68 * - zero or more ZIL records 69 * 70 * A ZIL record holds the information necessary to replay a single 71 * system call transaction. A ZIL block can hold many ZIL records, and 72 * the blocks are chained together, similarly to a singly linked list. 73 * 74 * Each ZIL block contains a block pointer (blkptr_t) to the next ZIL 75 * block in the chain, and the ZIL header points to the first block in 76 * the chain. 77 * 78 * Note, there is not a fixed place in the pool to hold these ZIL 79 * blocks; they are dynamically allocated and freed as needed from the 80 * blocks available on the pool, though they can be preferentially 81 * allocated from a dedicated "log" vdev. 82 */ 83 84/* 85 * This controls the amount of time that a ZIL block (lwb) will remain 86 * "open" when it isn't "full", and it has a thread waiting for it to be 87 * committed to stable storage. Please refer to the zil_commit_waiter() 88 * function (and the comments within it) for more details. 89 */ 90int zfs_commit_timeout_pct = 5; 91 92/* 93 * Disable intent logging replay. This global ZIL switch affects all pools. 94 */ 95int zil_replay_disable = 0; 96SYSCTL_DECL(_vfs_zfs); 97SYSCTL_INT(_vfs_zfs, OID_AUTO, zil_replay_disable, CTLFLAG_RWTUN, 98 &zil_replay_disable, 0, "Disable intent logging replay"); 99 100/* 101 * Disable the DKIOCFLUSHWRITECACHE commands that are normally sent to 102 * the disk(s) by the ZIL after an LWB write has completed. Setting this 103 * will cause ZIL corruption on power loss if a volatile out-of-order 104 * write cache is enabled. 105 */ 106boolean_t zil_nocacheflush = B_FALSE; 107SYSCTL_INT(_vfs_zfs, OID_AUTO, zil_nocacheflush, CTLFLAG_RWTUN, 108 &zil_nocacheflush, 0, "Disable ZIL cache flush"); 109 110boolean_t zfs_trim_enabled = B_TRUE; 111SYSCTL_DECL(_vfs_zfs_trim); 112SYSCTL_INT(_vfs_zfs_trim, OID_AUTO, enabled, CTLFLAG_RDTUN, &zfs_trim_enabled, 0, 113 "Enable ZFS TRIM"); 114 115/* 116 * Limit SLOG write size per commit executed with synchronous priority. 117 * Any writes above that will be executed with lower (asynchronous) priority 118 * to limit potential SLOG device abuse by single active ZIL writer. 119 */ 120uint64_t zil_slog_bulk = 768 * 1024; 121SYSCTL_QUAD(_vfs_zfs, OID_AUTO, zil_slog_bulk, CTLFLAG_RWTUN, 122 &zil_slog_bulk, 0, "Maximal SLOG commit size with sync priority"); 123 124static kmem_cache_t *zil_lwb_cache; 125static kmem_cache_t *zil_zcw_cache; 126 127#define LWB_EMPTY(lwb) ((BP_GET_LSIZE(&lwb->lwb_blk) - \ 128 sizeof (zil_chain_t)) == (lwb->lwb_sz - lwb->lwb_nused)) 129 130static int 131zil_bp_compare(const void *x1, const void *x2) 132{ 133 const dva_t *dva1 = &((zil_bp_node_t *)x1)->zn_dva; 134 const dva_t *dva2 = &((zil_bp_node_t *)x2)->zn_dva; 135 136 int cmp = AVL_CMP(DVA_GET_VDEV(dva1), DVA_GET_VDEV(dva2)); 137 if (likely(cmp)) 138 return (cmp); 139 140 return (AVL_CMP(DVA_GET_OFFSET(dva1), DVA_GET_OFFSET(dva2))); 141} 142 143static void 144zil_bp_tree_init(zilog_t *zilog) 145{ 146 avl_create(&zilog->zl_bp_tree, zil_bp_compare, 147 sizeof (zil_bp_node_t), offsetof(zil_bp_node_t, zn_node)); 148} 149 150static void 151zil_bp_tree_fini(zilog_t *zilog) 152{ 153 avl_tree_t *t = &zilog->zl_bp_tree; 154 zil_bp_node_t *zn; 155 void *cookie = NULL; 156 157 while ((zn = avl_destroy_nodes(t, &cookie)) != NULL) 158 kmem_free(zn, sizeof (zil_bp_node_t)); 159 160 avl_destroy(t); 161} 162 163int 164zil_bp_tree_add(zilog_t *zilog, const blkptr_t *bp) 165{ 166 avl_tree_t *t = &zilog->zl_bp_tree; 167 const dva_t *dva; 168 zil_bp_node_t *zn; 169 avl_index_t where; 170 171 if (BP_IS_EMBEDDED(bp)) 172 return (0); 173 174 dva = BP_IDENTITY(bp); 175 176 if (avl_find(t, dva, &where) != NULL) 177 return (SET_ERROR(EEXIST)); 178 179 zn = kmem_alloc(sizeof (zil_bp_node_t), KM_SLEEP); 180 zn->zn_dva = *dva; 181 avl_insert(t, zn, where); 182 183 return (0); 184} 185 186static zil_header_t * 187zil_header_in_syncing_context(zilog_t *zilog) 188{ 189 return ((zil_header_t *)zilog->zl_header); 190} 191 192static void 193zil_init_log_chain(zilog_t *zilog, blkptr_t *bp) 194{ 195 zio_cksum_t *zc = &bp->blk_cksum; 196 197 zc->zc_word[ZIL_ZC_GUID_0] = spa_get_random(-1ULL); 198 zc->zc_word[ZIL_ZC_GUID_1] = spa_get_random(-1ULL); 199 zc->zc_word[ZIL_ZC_OBJSET] = dmu_objset_id(zilog->zl_os); 200 zc->zc_word[ZIL_ZC_SEQ] = 1ULL; 201} 202 203/* 204 * Read a log block and make sure it's valid. 205 */ 206static int 207zil_read_log_block(zilog_t *zilog, const blkptr_t *bp, blkptr_t *nbp, void *dst, 208 char **end) 209{ 210 enum zio_flag zio_flags = ZIO_FLAG_CANFAIL; 211 arc_flags_t aflags = ARC_FLAG_WAIT; 212 arc_buf_t *abuf = NULL; 213 zbookmark_phys_t zb; 214 int error; 215 216 if (zilog->zl_header->zh_claim_txg == 0) 217 zio_flags |= ZIO_FLAG_SPECULATIVE | ZIO_FLAG_SCRUB; 218 219 if (!(zilog->zl_header->zh_flags & ZIL_CLAIM_LR_SEQ_VALID)) 220 zio_flags |= ZIO_FLAG_SPECULATIVE; 221 222 SET_BOOKMARK(&zb, bp->blk_cksum.zc_word[ZIL_ZC_OBJSET], 223 ZB_ZIL_OBJECT, ZB_ZIL_LEVEL, bp->blk_cksum.zc_word[ZIL_ZC_SEQ]); 224 225 error = arc_read(NULL, zilog->zl_spa, bp, arc_getbuf_func, &abuf, 226 ZIO_PRIORITY_SYNC_READ, zio_flags, &aflags, &zb); 227 228 if (error == 0) { 229 zio_cksum_t cksum = bp->blk_cksum; 230 231 /* 232 * Validate the checksummed log block. 233 * 234 * Sequence numbers should be... sequential. The checksum 235 * verifier for the next block should be bp's checksum plus 1. 236 * 237 * Also check the log chain linkage and size used. 238 */ 239 cksum.zc_word[ZIL_ZC_SEQ]++; 240 241 if (BP_GET_CHECKSUM(bp) == ZIO_CHECKSUM_ZILOG2) { 242 zil_chain_t *zilc = abuf->b_data; 243 char *lr = (char *)(zilc + 1); 244 uint64_t len = zilc->zc_nused - sizeof (zil_chain_t); 245 246 if (bcmp(&cksum, &zilc->zc_next_blk.blk_cksum, 247 sizeof (cksum)) || BP_IS_HOLE(&zilc->zc_next_blk)) { 248 error = SET_ERROR(ECKSUM); 249 } else { 250 ASSERT3U(len, <=, SPA_OLD_MAXBLOCKSIZE); 251 bcopy(lr, dst, len); 252 *end = (char *)dst + len; 253 *nbp = zilc->zc_next_blk; 254 } 255 } else { 256 char *lr = abuf->b_data; 257 uint64_t size = BP_GET_LSIZE(bp); 258 zil_chain_t *zilc = (zil_chain_t *)(lr + size) - 1; 259 260 if (bcmp(&cksum, &zilc->zc_next_blk.blk_cksum, 261 sizeof (cksum)) || BP_IS_HOLE(&zilc->zc_next_blk) || 262 (zilc->zc_nused > (size - sizeof (*zilc)))) { 263 error = SET_ERROR(ECKSUM); 264 } else { 265 ASSERT3U(zilc->zc_nused, <=, 266 SPA_OLD_MAXBLOCKSIZE); 267 bcopy(lr, dst, zilc->zc_nused); 268 *end = (char *)dst + zilc->zc_nused; 269 *nbp = zilc->zc_next_blk; 270 } 271 } 272 273 arc_buf_destroy(abuf, &abuf); 274 } 275 276 return (error); 277} 278 279/* 280 * Read a TX_WRITE log data block. 281 */ 282static int 283zil_read_log_data(zilog_t *zilog, const lr_write_t *lr, void *wbuf) 284{ 285 enum zio_flag zio_flags = ZIO_FLAG_CANFAIL; 286 const blkptr_t *bp = &lr->lr_blkptr; 287 arc_flags_t aflags = ARC_FLAG_WAIT; 288 arc_buf_t *abuf = NULL; 289 zbookmark_phys_t zb; 290 int error; 291 292 if (BP_IS_HOLE(bp)) { 293 if (wbuf != NULL) 294 bzero(wbuf, MAX(BP_GET_LSIZE(bp), lr->lr_length)); 295 return (0); 296 } 297 298 if (zilog->zl_header->zh_claim_txg == 0) 299 zio_flags |= ZIO_FLAG_SPECULATIVE | ZIO_FLAG_SCRUB; 300 301 SET_BOOKMARK(&zb, dmu_objset_id(zilog->zl_os), lr->lr_foid, 302 ZB_ZIL_LEVEL, lr->lr_offset / BP_GET_LSIZE(bp)); 303 304 error = arc_read(NULL, zilog->zl_spa, bp, arc_getbuf_func, &abuf, 305 ZIO_PRIORITY_SYNC_READ, zio_flags, &aflags, &zb); 306 307 if (error == 0) { 308 if (wbuf != NULL) 309 bcopy(abuf->b_data, wbuf, arc_buf_size(abuf)); 310 arc_buf_destroy(abuf, &abuf); 311 } 312 313 return (error); 314} 315 316/* 317 * Parse the intent log, and call parse_func for each valid record within. 318 */ 319int 320zil_parse(zilog_t *zilog, zil_parse_blk_func_t *parse_blk_func, 321 zil_parse_lr_func_t *parse_lr_func, void *arg, uint64_t txg) 322{ 323 const zil_header_t *zh = zilog->zl_header; 324 boolean_t claimed = !!zh->zh_claim_txg; 325 uint64_t claim_blk_seq = claimed ? zh->zh_claim_blk_seq : UINT64_MAX; 326 uint64_t claim_lr_seq = claimed ? zh->zh_claim_lr_seq : UINT64_MAX; 327 uint64_t max_blk_seq = 0; 328 uint64_t max_lr_seq = 0; 329 uint64_t blk_count = 0; 330 uint64_t lr_count = 0; 331 blkptr_t blk, next_blk; 332 char *lrbuf, *lrp; 333 int error = 0; 334 335 /* 336 * Old logs didn't record the maximum zh_claim_lr_seq. 337 */ 338 if (!(zh->zh_flags & ZIL_CLAIM_LR_SEQ_VALID)) 339 claim_lr_seq = UINT64_MAX; 340 341 /* 342 * Starting at the block pointed to by zh_log we read the log chain. 343 * For each block in the chain we strongly check that block to 344 * ensure its validity. We stop when an invalid block is found. 345 * For each block pointer in the chain we call parse_blk_func(). 346 * For each record in each valid block we call parse_lr_func(). 347 * If the log has been claimed, stop if we encounter a sequence 348 * number greater than the highest claimed sequence number. 349 */ 350 lrbuf = zio_buf_alloc(SPA_OLD_MAXBLOCKSIZE); 351 zil_bp_tree_init(zilog); 352 353 for (blk = zh->zh_log; !BP_IS_HOLE(&blk); blk = next_blk) { 354 uint64_t blk_seq = blk.blk_cksum.zc_word[ZIL_ZC_SEQ]; 355 int reclen; 356 char *end; 357 358 if (blk_seq > claim_blk_seq) 359 break; 360 if ((error = parse_blk_func(zilog, &blk, arg, txg)) != 0) 361 break; 362 ASSERT3U(max_blk_seq, <, blk_seq); 363 max_blk_seq = blk_seq; 364 blk_count++; 365 366 if (max_lr_seq == claim_lr_seq && max_blk_seq == claim_blk_seq) 367 break; 368 369 error = zil_read_log_block(zilog, &blk, &next_blk, lrbuf, &end); 370 if (error != 0) 371 break; 372 373 for (lrp = lrbuf; lrp < end; lrp += reclen) { 374 lr_t *lr = (lr_t *)lrp; 375 reclen = lr->lrc_reclen; 376 ASSERT3U(reclen, >=, sizeof (lr_t)); 377 if (lr->lrc_seq > claim_lr_seq) 378 goto done; 379 if ((error = parse_lr_func(zilog, lr, arg, txg)) != 0) 380 goto done; 381 ASSERT3U(max_lr_seq, <, lr->lrc_seq); 382 max_lr_seq = lr->lrc_seq; 383 lr_count++; 384 } 385 } 386done: 387 zilog->zl_parse_error = error; 388 zilog->zl_parse_blk_seq = max_blk_seq; 389 zilog->zl_parse_lr_seq = max_lr_seq; 390 zilog->zl_parse_blk_count = blk_count; 391 zilog->zl_parse_lr_count = lr_count; 392 393 ASSERT(!claimed || !(zh->zh_flags & ZIL_CLAIM_LR_SEQ_VALID) || 394 (max_blk_seq == claim_blk_seq && max_lr_seq == claim_lr_seq)); 395 396 zil_bp_tree_fini(zilog); 397 zio_buf_free(lrbuf, SPA_OLD_MAXBLOCKSIZE); 398 399 return (error); 400} 401 402/* ARGSUSED */ 403static int 404zil_clear_log_block(zilog_t *zilog, blkptr_t *bp, void *tx, uint64_t first_txg) 405{ 406 ASSERT(!BP_IS_HOLE(bp)); 407 408 /* 409 * As we call this function from the context of a rewind to a 410 * checkpoint, each ZIL block whose txg is later than the txg 411 * that we rewind to is invalid. Thus, we return -1 so 412 * zil_parse() doesn't attempt to read it. 413 */ 414 if (bp->blk_birth >= first_txg) 415 return (-1); 416 417 if (zil_bp_tree_add(zilog, bp) != 0) 418 return (0); 419 420 zio_free(zilog->zl_spa, first_txg, bp); 421 return (0); 422} 423 424/* ARGSUSED */ 425static int 426zil_noop_log_record(zilog_t *zilog, lr_t *lrc, void *tx, uint64_t first_txg) 427{ 428 return (0); 429} 430 431static int 432zil_claim_log_block(zilog_t *zilog, blkptr_t *bp, void *tx, uint64_t first_txg) 433{ 434 /* 435 * Claim log block if not already committed and not already claimed. 436 * If tx == NULL, just verify that the block is claimable. 437 */ 438 if (BP_IS_HOLE(bp) || bp->blk_birth < first_txg || 439 zil_bp_tree_add(zilog, bp) != 0) 440 return (0); 441 442 return (zio_wait(zio_claim(NULL, zilog->zl_spa, 443 tx == NULL ? 0 : first_txg, bp, spa_claim_notify, NULL, 444 ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE | ZIO_FLAG_SCRUB))); 445} 446 447static int 448zil_claim_log_record(zilog_t *zilog, lr_t *lrc, void *tx, uint64_t first_txg) 449{ 450 lr_write_t *lr = (lr_write_t *)lrc; 451 int error; 452 453 if (lrc->lrc_txtype != TX_WRITE) 454 return (0); 455 456 /* 457 * If the block is not readable, don't claim it. This can happen 458 * in normal operation when a log block is written to disk before 459 * some of the dmu_sync() blocks it points to. In this case, the 460 * transaction cannot have been committed to anyone (we would have 461 * waited for all writes to be stable first), so it is semantically 462 * correct to declare this the end of the log. 463 */ 464 if (lr->lr_blkptr.blk_birth >= first_txg && 465 (error = zil_read_log_data(zilog, lr, NULL)) != 0) 466 return (error); 467 return (zil_claim_log_block(zilog, &lr->lr_blkptr, tx, first_txg)); 468} 469 470/* ARGSUSED */ 471static int 472zil_free_log_block(zilog_t *zilog, blkptr_t *bp, void *tx, uint64_t claim_txg) 473{ 474 zio_free(zilog->zl_spa, dmu_tx_get_txg(tx), bp); 475 476 return (0); 477} 478 479static int 480zil_free_log_record(zilog_t *zilog, lr_t *lrc, void *tx, uint64_t claim_txg) 481{ 482 lr_write_t *lr = (lr_write_t *)lrc; 483 blkptr_t *bp = &lr->lr_blkptr; 484 485 /* 486 * If we previously claimed it, we need to free it. 487 */ 488 if (claim_txg != 0 && lrc->lrc_txtype == TX_WRITE && 489 bp->blk_birth >= claim_txg && zil_bp_tree_add(zilog, bp) == 0 && 490 !BP_IS_HOLE(bp)) 491 zio_free(zilog->zl_spa, dmu_tx_get_txg(tx), bp); 492 493 return (0); 494} 495 496static int 497zil_lwb_vdev_compare(const void *x1, const void *x2) 498{ 499 const uint64_t v1 = ((zil_vdev_node_t *)x1)->zv_vdev; 500 const uint64_t v2 = ((zil_vdev_node_t *)x2)->zv_vdev; 501 502 return (AVL_CMP(v1, v2)); 503} 504 505static lwb_t * 506zil_alloc_lwb(zilog_t *zilog, blkptr_t *bp, boolean_t slog, uint64_t txg) 507{ 508 lwb_t *lwb; 509 510 lwb = kmem_cache_alloc(zil_lwb_cache, KM_SLEEP); 511 lwb->lwb_zilog = zilog; 512 lwb->lwb_blk = *bp; 513 lwb->lwb_slog = slog; 514 lwb->lwb_state = LWB_STATE_CLOSED; 515 lwb->lwb_buf = zio_buf_alloc(BP_GET_LSIZE(bp)); 516 lwb->lwb_max_txg = txg; 517 lwb->lwb_write_zio = NULL; 518 lwb->lwb_root_zio = NULL; 519 lwb->lwb_tx = NULL; 520 lwb->lwb_issued_timestamp = 0; 521 if (BP_GET_CHECKSUM(bp) == ZIO_CHECKSUM_ZILOG2) { 522 lwb->lwb_nused = sizeof (zil_chain_t); 523 lwb->lwb_sz = BP_GET_LSIZE(bp); 524 } else { 525 lwb->lwb_nused = 0; 526 lwb->lwb_sz = BP_GET_LSIZE(bp) - sizeof (zil_chain_t); 527 } 528 529 mutex_enter(&zilog->zl_lock); 530 list_insert_tail(&zilog->zl_lwb_list, lwb); 531 mutex_exit(&zilog->zl_lock); 532 533 ASSERT(!MUTEX_HELD(&lwb->lwb_vdev_lock)); 534 ASSERT(avl_is_empty(&lwb->lwb_vdev_tree)); 535 VERIFY(list_is_empty(&lwb->lwb_waiters)); 536 537 return (lwb); 538} 539 540static void 541zil_free_lwb(zilog_t *zilog, lwb_t *lwb) 542{ 543 ASSERT(MUTEX_HELD(&zilog->zl_lock)); 544 ASSERT(!MUTEX_HELD(&lwb->lwb_vdev_lock)); 545 VERIFY(list_is_empty(&lwb->lwb_waiters)); 546 ASSERT(avl_is_empty(&lwb->lwb_vdev_tree)); 547 ASSERT3P(lwb->lwb_write_zio, ==, NULL); 548 ASSERT3P(lwb->lwb_root_zio, ==, NULL); 549 ASSERT3U(lwb->lwb_max_txg, <=, spa_syncing_txg(zilog->zl_spa)); 550 ASSERT(lwb->lwb_state == LWB_STATE_CLOSED || 551 lwb->lwb_state == LWB_STATE_FLUSH_DONE); 552 553 /* 554 * Clear the zilog's field to indicate this lwb is no longer 555 * valid, and prevent use-after-free errors. 556 */ 557 if (zilog->zl_last_lwb_opened == lwb) 558 zilog->zl_last_lwb_opened = NULL; 559 560 kmem_cache_free(zil_lwb_cache, lwb); 561} 562 563/* 564 * Called when we create in-memory log transactions so that we know 565 * to cleanup the itxs at the end of spa_sync(). 566 */ 567void 568zilog_dirty(zilog_t *zilog, uint64_t txg) 569{ 570 dsl_pool_t *dp = zilog->zl_dmu_pool; 571 dsl_dataset_t *ds = dmu_objset_ds(zilog->zl_os); 572 573 ASSERT(spa_writeable(zilog->zl_spa)); 574 575 if (ds->ds_is_snapshot) 576 panic("dirtying snapshot!"); 577 578 if (txg_list_add(&dp->dp_dirty_zilogs, zilog, txg)) { 579 /* up the hold count until we can be written out */ 580 dmu_buf_add_ref(ds->ds_dbuf, zilog); 581 582 zilog->zl_dirty_max_txg = MAX(txg, zilog->zl_dirty_max_txg); 583 } 584} 585 586/* 587 * Determine if the zil is dirty in the specified txg. Callers wanting to 588 * ensure that the dirty state does not change must hold the itxg_lock for 589 * the specified txg. Holding the lock will ensure that the zil cannot be 590 * dirtied (zil_itx_assign) or cleaned (zil_clean) while we check its current 591 * state. 592 */ 593boolean_t 594zilog_is_dirty_in_txg(zilog_t *zilog, uint64_t txg) 595{ 596 dsl_pool_t *dp = zilog->zl_dmu_pool; 597 598 if (txg_list_member(&dp->dp_dirty_zilogs, zilog, txg & TXG_MASK)) 599 return (B_TRUE); 600 return (B_FALSE); 601} 602 603/* 604 * Determine if the zil is dirty. The zil is considered dirty if it has 605 * any pending itx records that have not been cleaned by zil_clean(). 606 */ 607boolean_t 608zilog_is_dirty(zilog_t *zilog) 609{ 610 dsl_pool_t *dp = zilog->zl_dmu_pool; 611 612 for (int t = 0; t < TXG_SIZE; t++) { 613 if (txg_list_member(&dp->dp_dirty_zilogs, zilog, t)) 614 return (B_TRUE); 615 } 616 return (B_FALSE); 617} 618 619/* 620 * Create an on-disk intent log. 621 */ 622static lwb_t * 623zil_create(zilog_t *zilog) 624{ 625 const zil_header_t *zh = zilog->zl_header; 626 lwb_t *lwb = NULL; 627 uint64_t txg = 0; 628 dmu_tx_t *tx = NULL; 629 blkptr_t blk; 630 int error = 0; 631 boolean_t slog = FALSE; 632 633 /* 634 * Wait for any previous destroy to complete. 635 */ 636 txg_wait_synced(zilog->zl_dmu_pool, zilog->zl_destroy_txg); 637 638 ASSERT(zh->zh_claim_txg == 0); 639 ASSERT(zh->zh_replay_seq == 0); 640 641 blk = zh->zh_log; 642 643 /* 644 * Allocate an initial log block if: 645 * - there isn't one already 646 * - the existing block is the wrong endianess 647 */ 648 if (BP_IS_HOLE(&blk) || BP_SHOULD_BYTESWAP(&blk)) { 649 tx = dmu_tx_create(zilog->zl_os); 650 VERIFY0(dmu_tx_assign(tx, TXG_WAIT)); 651 dsl_dataset_dirty(dmu_objset_ds(zilog->zl_os), tx); 652 txg = dmu_tx_get_txg(tx); 653 654 if (!BP_IS_HOLE(&blk)) { 655 zio_free(zilog->zl_spa, txg, &blk); 656 BP_ZERO(&blk); 657 } 658 659 error = zio_alloc_zil(zilog->zl_spa, 660 zilog->zl_os->os_dsl_dataset->ds_object, txg, &blk, NULL, 661 ZIL_MIN_BLKSZ, &slog); 662 663 if (error == 0) 664 zil_init_log_chain(zilog, &blk); 665 } 666 667 /* 668 * Allocate a log write block (lwb) for the first log block. 669 */ 670 if (error == 0) 671 lwb = zil_alloc_lwb(zilog, &blk, slog, txg); 672 673 /* 674 * If we just allocated the first log block, commit our transaction 675 * and wait for zil_sync() to stuff the block poiner into zh_log. 676 * (zh is part of the MOS, so we cannot modify it in open context.) 677 */ 678 if (tx != NULL) { 679 dmu_tx_commit(tx); 680 txg_wait_synced(zilog->zl_dmu_pool, txg); 681 } 682 683 ASSERT(bcmp(&blk, &zh->zh_log, sizeof (blk)) == 0); 684 685 return (lwb); 686} 687 688/* 689 * In one tx, free all log blocks and clear the log header. If keep_first 690 * is set, then we're replaying a log with no content. We want to keep the 691 * first block, however, so that the first synchronous transaction doesn't 692 * require a txg_wait_synced() in zil_create(). We don't need to 693 * txg_wait_synced() here either when keep_first is set, because both 694 * zil_create() and zil_destroy() will wait for any in-progress destroys 695 * to complete. 696 */ 697void 698zil_destroy(zilog_t *zilog, boolean_t keep_first) 699{ 700 const zil_header_t *zh = zilog->zl_header; 701 lwb_t *lwb; 702 dmu_tx_t *tx; 703 uint64_t txg; 704 705 /* 706 * Wait for any previous destroy to complete. 707 */ 708 txg_wait_synced(zilog->zl_dmu_pool, zilog->zl_destroy_txg); 709 710 zilog->zl_old_header = *zh; /* debugging aid */ 711 712 if (BP_IS_HOLE(&zh->zh_log)) 713 return; 714 715 tx = dmu_tx_create(zilog->zl_os); 716 VERIFY0(dmu_tx_assign(tx, TXG_WAIT)); 717 dsl_dataset_dirty(dmu_objset_ds(zilog->zl_os), tx); 718 txg = dmu_tx_get_txg(tx); 719 720 mutex_enter(&zilog->zl_lock); 721 722 ASSERT3U(zilog->zl_destroy_txg, <, txg); 723 zilog->zl_destroy_txg = txg; 724 zilog->zl_keep_first = keep_first; 725 726 if (!list_is_empty(&zilog->zl_lwb_list)) { 727 ASSERT(zh->zh_claim_txg == 0); 728 VERIFY(!keep_first); 729 while ((lwb = list_head(&zilog->zl_lwb_list)) != NULL) { 730 list_remove(&zilog->zl_lwb_list, lwb); 731 if (lwb->lwb_buf != NULL) 732 zio_buf_free(lwb->lwb_buf, lwb->lwb_sz); 733 zio_free(zilog->zl_spa, txg, &lwb->lwb_blk); 734 zil_free_lwb(zilog, lwb); 735 } 736 } else if (!keep_first) { 737 zil_destroy_sync(zilog, tx); 738 } 739 mutex_exit(&zilog->zl_lock); 740 741 dmu_tx_commit(tx); 742} 743 744void 745zil_destroy_sync(zilog_t *zilog, dmu_tx_t *tx) 746{ 747 ASSERT(list_is_empty(&zilog->zl_lwb_list)); 748 (void) zil_parse(zilog, zil_free_log_block, 749 zil_free_log_record, tx, zilog->zl_header->zh_claim_txg); 750} 751 752int 753zil_claim(dsl_pool_t *dp, dsl_dataset_t *ds, void *txarg) 754{ 755 dmu_tx_t *tx = txarg; 756 zilog_t *zilog; 757 uint64_t first_txg; 758 zil_header_t *zh; 759 objset_t *os; 760 int error; 761 762 error = dmu_objset_own_obj(dp, ds->ds_object, 763 DMU_OST_ANY, B_FALSE, FTAG, &os); 764 if (error != 0) { 765 /* 766 * EBUSY indicates that the objset is inconsistent, in which 767 * case it can not have a ZIL. 768 */ 769 if (error != EBUSY) { 770 cmn_err(CE_WARN, "can't open objset for %llu, error %u", 771 (unsigned long long)ds->ds_object, error); 772 } 773 return (0); 774 } 775 776 zilog = dmu_objset_zil(os); 777 zh = zil_header_in_syncing_context(zilog); 778 ASSERT3U(tx->tx_txg, ==, spa_first_txg(zilog->zl_spa)); 779 first_txg = spa_min_claim_txg(zilog->zl_spa); 780 781 /* 782 * If the spa_log_state is not set to be cleared, check whether 783 * the current uberblock is a checkpoint one and if the current 784 * header has been claimed before moving on. 785 * 786 * If the current uberblock is a checkpointed uberblock then 787 * one of the following scenarios took place: 788 * 789 * 1] We are currently rewinding to the checkpoint of the pool. 790 * 2] We crashed in the middle of a checkpoint rewind but we 791 * did manage to write the checkpointed uberblock to the 792 * vdev labels, so when we tried to import the pool again 793 * the checkpointed uberblock was selected from the import 794 * procedure. 795 * 796 * In both cases we want to zero out all the ZIL blocks, except 797 * the ones that have been claimed at the time of the checkpoint 798 * (their zh_claim_txg != 0). The reason is that these blocks 799 * may be corrupted since we may have reused their locations on 800 * disk after we took the checkpoint. 801 * 802 * We could try to set spa_log_state to SPA_LOG_CLEAR earlier 803 * when we first figure out whether the current uberblock is 804 * checkpointed or not. Unfortunately, that would discard all 805 * the logs, including the ones that are claimed, and we would 806 * leak space. 807 */ 808 if (spa_get_log_state(zilog->zl_spa) == SPA_LOG_CLEAR || 809 (zilog->zl_spa->spa_uberblock.ub_checkpoint_txg != 0 && 810 zh->zh_claim_txg == 0)) { 811 if (!BP_IS_HOLE(&zh->zh_log)) { 812 (void) zil_parse(zilog, zil_clear_log_block, 813 zil_noop_log_record, tx, first_txg); 814 } 815 BP_ZERO(&zh->zh_log); 816 dsl_dataset_dirty(dmu_objset_ds(os), tx); 817 dmu_objset_disown(os, FTAG); 818 return (0); 819 } 820 821 /* 822 * If we are not rewinding and opening the pool normally, then 823 * the min_claim_txg should be equal to the first txg of the pool. 824 */ 825 ASSERT3U(first_txg, ==, spa_first_txg(zilog->zl_spa)); 826 827 /* 828 * Claim all log blocks if we haven't already done so, and remember 829 * the highest claimed sequence number. This ensures that if we can 830 * read only part of the log now (e.g. due to a missing device), 831 * but we can read the entire log later, we will not try to replay 832 * or destroy beyond the last block we successfully claimed. 833 */ 834 ASSERT3U(zh->zh_claim_txg, <=, first_txg); 835 if (zh->zh_claim_txg == 0 && !BP_IS_HOLE(&zh->zh_log)) { 836 (void) zil_parse(zilog, zil_claim_log_block, 837 zil_claim_log_record, tx, first_txg); 838 zh->zh_claim_txg = first_txg; 839 zh->zh_claim_blk_seq = zilog->zl_parse_blk_seq; 840 zh->zh_claim_lr_seq = zilog->zl_parse_lr_seq; 841 if (zilog->zl_parse_lr_count || zilog->zl_parse_blk_count > 1) 842 zh->zh_flags |= ZIL_REPLAY_NEEDED; 843 zh->zh_flags |= ZIL_CLAIM_LR_SEQ_VALID; 844 dsl_dataset_dirty(dmu_objset_ds(os), tx); 845 } 846 847 ASSERT3U(first_txg, ==, (spa_last_synced_txg(zilog->zl_spa) + 1)); 848 dmu_objset_disown(os, FTAG); 849 return (0); 850} 851 852/* 853 * Check the log by walking the log chain. 854 * Checksum errors are ok as they indicate the end of the chain. 855 * Any other error (no device or read failure) returns an error. 856 */ 857/* ARGSUSED */ 858int 859zil_check_log_chain(dsl_pool_t *dp, dsl_dataset_t *ds, void *tx) 860{ 861 zilog_t *zilog; 862 objset_t *os; 863 blkptr_t *bp; 864 int error; 865 866 ASSERT(tx == NULL); 867 868 error = dmu_objset_from_ds(ds, &os); 869 if (error != 0) { 870 cmn_err(CE_WARN, "can't open objset %llu, error %d", 871 (unsigned long long)ds->ds_object, error); 872 return (0); 873 } 874 875 zilog = dmu_objset_zil(os); 876 bp = (blkptr_t *)&zilog->zl_header->zh_log; 877 878 if (!BP_IS_HOLE(bp)) { 879 vdev_t *vd; 880 boolean_t valid = B_TRUE; 881 882 /* 883 * Check the first block and determine if it's on a log device 884 * which may have been removed or faulted prior to loading this 885 * pool. If so, there's no point in checking the rest of the 886 * log as its content should have already been synced to the 887 * pool. 888 */ 889 spa_config_enter(os->os_spa, SCL_STATE, FTAG, RW_READER); 890 vd = vdev_lookup_top(os->os_spa, DVA_GET_VDEV(&bp->blk_dva[0])); 891 if (vd->vdev_islog && vdev_is_dead(vd)) 892 valid = vdev_log_state_valid(vd); 893 spa_config_exit(os->os_spa, SCL_STATE, FTAG); 894 895 if (!valid) 896 return (0); 897 898 /* 899 * Check whether the current uberblock is checkpointed (e.g. 900 * we are rewinding) and whether the current header has been 901 * claimed or not. If it hasn't then skip verifying it. We 902 * do this because its ZIL blocks may be part of the pool's 903 * state before the rewind, which is no longer valid. 904 */ 905 zil_header_t *zh = zil_header_in_syncing_context(zilog); 906 if (zilog->zl_spa->spa_uberblock.ub_checkpoint_txg != 0 && 907 zh->zh_claim_txg == 0) 908 return (0); 909 } 910 911 /* 912 * Because tx == NULL, zil_claim_log_block() will not actually claim 913 * any blocks, but just determine whether it is possible to do so. 914 * In addition to checking the log chain, zil_claim_log_block() 915 * will invoke zio_claim() with a done func of spa_claim_notify(), 916 * which will update spa_max_claim_txg. See spa_load() for details. 917 */ 918 error = zil_parse(zilog, zil_claim_log_block, zil_claim_log_record, tx, 919 zilog->zl_header->zh_claim_txg ? -1ULL : 920 spa_min_claim_txg(os->os_spa)); 921 922 return ((error == ECKSUM || error == ENOENT) ? 0 : error); 923} 924 925/* 926 * When an itx is "skipped", this function is used to properly mark the 927 * waiter as "done, and signal any thread(s) waiting on it. An itx can 928 * be skipped (and not committed to an lwb) for a variety of reasons, 929 * one of them being that the itx was committed via spa_sync(), prior to 930 * it being committed to an lwb; this can happen if a thread calling 931 * zil_commit() is racing with spa_sync(). 932 */ 933static void 934zil_commit_waiter_skip(zil_commit_waiter_t *zcw) 935{ 936 mutex_enter(&zcw->zcw_lock); 937 ASSERT3B(zcw->zcw_done, ==, B_FALSE); 938 zcw->zcw_done = B_TRUE; 939 cv_broadcast(&zcw->zcw_cv); 940 mutex_exit(&zcw->zcw_lock); 941} 942 943/* 944 * This function is used when the given waiter is to be linked into an 945 * lwb's "lwb_waiter" list; i.e. when the itx is committed to the lwb. 946 * At this point, the waiter will no longer be referenced by the itx, 947 * and instead, will be referenced by the lwb. 948 */ 949static void 950zil_commit_waiter_link_lwb(zil_commit_waiter_t *zcw, lwb_t *lwb) 951{ 952 /* 953 * The lwb_waiters field of the lwb is protected by the zilog's 954 * zl_lock, thus it must be held when calling this function. 955 */ 956 ASSERT(MUTEX_HELD(&lwb->lwb_zilog->zl_lock)); 957 958 mutex_enter(&zcw->zcw_lock); 959 ASSERT(!list_link_active(&zcw->zcw_node)); 960 ASSERT3P(zcw->zcw_lwb, ==, NULL); 961 ASSERT3P(lwb, !=, NULL); 962 ASSERT(lwb->lwb_state == LWB_STATE_OPENED || 963 lwb->lwb_state == LWB_STATE_ISSUED || 964 lwb->lwb_state == LWB_STATE_WRITE_DONE); 965 966 list_insert_tail(&lwb->lwb_waiters, zcw); 967 zcw->zcw_lwb = lwb; 968 mutex_exit(&zcw->zcw_lock); 969} 970 971/* 972 * This function is used when zio_alloc_zil() fails to allocate a ZIL 973 * block, and the given waiter must be linked to the "nolwb waiters" 974 * list inside of zil_process_commit_list(). 975 */ 976static void 977zil_commit_waiter_link_nolwb(zil_commit_waiter_t *zcw, list_t *nolwb) 978{ 979 mutex_enter(&zcw->zcw_lock); 980 ASSERT(!list_link_active(&zcw->zcw_node)); 981 ASSERT3P(zcw->zcw_lwb, ==, NULL); 982 list_insert_tail(nolwb, zcw); 983 mutex_exit(&zcw->zcw_lock); 984} 985 986void 987zil_lwb_add_block(lwb_t *lwb, const blkptr_t *bp) 988{ 989 avl_tree_t *t = &lwb->lwb_vdev_tree; 990 avl_index_t where; 991 zil_vdev_node_t *zv, zvsearch; 992 int ndvas = BP_GET_NDVAS(bp); 993 int i; 994 995 if (zil_nocacheflush) 996 return; 997 998 mutex_enter(&lwb->lwb_vdev_lock); 999 for (i = 0; i < ndvas; i++) { 1000 zvsearch.zv_vdev = DVA_GET_VDEV(&bp->blk_dva[i]); 1001 if (avl_find(t, &zvsearch, &where) == NULL) { 1002 zv = kmem_alloc(sizeof (*zv), KM_SLEEP); 1003 zv->zv_vdev = zvsearch.zv_vdev; 1004 avl_insert(t, zv, where); 1005 } 1006 } 1007 mutex_exit(&lwb->lwb_vdev_lock); 1008} 1009 1010static void 1011zil_lwb_flush_defer(lwb_t *lwb, lwb_t *nlwb) 1012{ 1013 avl_tree_t *src = &lwb->lwb_vdev_tree; 1014 avl_tree_t *dst = &nlwb->lwb_vdev_tree; 1015 void *cookie = NULL; 1016 zil_vdev_node_t *zv; 1017 1018 ASSERT3S(lwb->lwb_state, ==, LWB_STATE_WRITE_DONE); 1019 ASSERT3S(nlwb->lwb_state, !=, LWB_STATE_WRITE_DONE); 1020 ASSERT3S(nlwb->lwb_state, !=, LWB_STATE_FLUSH_DONE); 1021 1022 /* 1023 * While 'lwb' is at a point in its lifetime where lwb_vdev_tree does 1024 * not need the protection of lwb_vdev_lock (it will only be modified 1025 * while holding zilog->zl_lock) as its writes and those of its 1026 * children have all completed. The younger 'nlwb' may be waiting on 1027 * future writes to additional vdevs. 1028 */ 1029 mutex_enter(&nlwb->lwb_vdev_lock); 1030 /* 1031 * Tear down the 'lwb' vdev tree, ensuring that entries which do not 1032 * exist in 'nlwb' are moved to it, freeing any would-be duplicates. 1033 */ 1034 while ((zv = avl_destroy_nodes(src, &cookie)) != NULL) { 1035 avl_index_t where; 1036 1037 if (avl_find(dst, zv, &where) == NULL) { 1038 avl_insert(dst, zv, where); 1039 } else { 1040 kmem_free(zv, sizeof (*zv)); 1041 } 1042 } 1043 mutex_exit(&nlwb->lwb_vdev_lock); 1044} 1045 1046void 1047zil_lwb_add_txg(lwb_t *lwb, uint64_t txg) 1048{ 1049 lwb->lwb_max_txg = MAX(lwb->lwb_max_txg, txg); 1050} 1051 1052/* 1053 * This function is a called after all vdevs associated with a given lwb 1054 * write have completed their DKIOCFLUSHWRITECACHE command; or as soon 1055 * as the lwb write completes, if "zil_nocacheflush" is set. Further, 1056 * all "previous" lwb's will have completed before this function is 1057 * called; i.e. this function is called for all previous lwbs before 1058 * it's called for "this" lwb (enforced via zio the dependencies 1059 * configured in zil_lwb_set_zio_dependency()). 1060 * 1061 * The intention is for this function to be called as soon as the 1062 * contents of an lwb are considered "stable" on disk, and will survive 1063 * any sudden loss of power. At this point, any threads waiting for the 1064 * lwb to reach this state are signalled, and the "waiter" structures 1065 * are marked "done". 1066 */ 1067static void 1068zil_lwb_flush_vdevs_done(zio_t *zio) 1069{ 1070 lwb_t *lwb = zio->io_private; 1071 zilog_t *zilog = lwb->lwb_zilog; 1072 dmu_tx_t *tx = lwb->lwb_tx; 1073 zil_commit_waiter_t *zcw; 1074 1075 spa_config_exit(zilog->zl_spa, SCL_STATE, lwb); 1076 1077 zio_buf_free(lwb->lwb_buf, lwb->lwb_sz); 1078 1079 mutex_enter(&zilog->zl_lock); 1080 1081 /* 1082 * Ensure the lwb buffer pointer is cleared before releasing the 1083 * txg. If we have had an allocation failure and the txg is 1084 * waiting to sync then we want zil_sync() to remove the lwb so 1085 * that it's not picked up as the next new one in 1086 * zil_process_commit_list(). zil_sync() will only remove the 1087 * lwb if lwb_buf is null. 1088 */ 1089 lwb->lwb_buf = NULL; 1090 lwb->lwb_tx = NULL; 1091 1092 ASSERT3U(lwb->lwb_issued_timestamp, >, 0); 1093 zilog->zl_last_lwb_latency = gethrtime() - lwb->lwb_issued_timestamp; 1094 1095 lwb->lwb_root_zio = NULL; 1096 1097 ASSERT3S(lwb->lwb_state, ==, LWB_STATE_WRITE_DONE); 1098 lwb->lwb_state = LWB_STATE_FLUSH_DONE; 1099 1100 if (zilog->zl_last_lwb_opened == lwb) { 1101 /* 1102 * Remember the highest committed log sequence number 1103 * for ztest. We only update this value when all the log 1104 * writes succeeded, because ztest wants to ASSERT that 1105 * it got the whole log chain. 1106 */ 1107 zilog->zl_commit_lr_seq = zilog->zl_lr_seq; 1108 } 1109 1110 while ((zcw = list_head(&lwb->lwb_waiters)) != NULL) { 1111 mutex_enter(&zcw->zcw_lock); 1112 1113 ASSERT(list_link_active(&zcw->zcw_node)); 1114 list_remove(&lwb->lwb_waiters, zcw); 1115 1116 ASSERT3P(zcw->zcw_lwb, ==, lwb); 1117 zcw->zcw_lwb = NULL; 1118 1119 zcw->zcw_zio_error = zio->io_error; 1120 1121 ASSERT3B(zcw->zcw_done, ==, B_FALSE); 1122 zcw->zcw_done = B_TRUE; 1123 cv_broadcast(&zcw->zcw_cv); 1124 1125 mutex_exit(&zcw->zcw_lock); 1126 } 1127 1128 mutex_exit(&zilog->zl_lock); 1129 1130 /* 1131 * Now that we've written this log block, we have a stable pointer 1132 * to the next block in the chain, so it's OK to let the txg in 1133 * which we allocated the next block sync. 1134 */ 1135 dmu_tx_commit(tx); 1136} 1137 1138/* 1139 * This is called when an lwb's write zio completes. The callback's 1140 * purpose is to issue the DKIOCFLUSHWRITECACHE commands for the vdevs 1141 * in the lwb's lwb_vdev_tree. The tree will contain the vdevs involved 1142 * in writing out this specific lwb's data, and in the case that cache 1143 * flushes have been deferred, vdevs involved in writing the data for 1144 * previous lwbs. The writes corresponding to all the vdevs in the 1145 * lwb_vdev_tree will have completed by the time this is called, due to 1146 * the zio dependencies configured in zil_lwb_set_zio_dependency(), 1147 * which takes deferred flushes into account. The lwb will be "done" 1148 * once zil_lwb_flush_vdevs_done() is called, which occurs in the zio 1149 * completion callback for the lwb's root zio. 1150 */ 1151static void 1152zil_lwb_write_done(zio_t *zio) 1153{ 1154 lwb_t *lwb = zio->io_private; 1155 spa_t *spa = zio->io_spa; 1156 zilog_t *zilog = lwb->lwb_zilog; 1157 avl_tree_t *t = &lwb->lwb_vdev_tree; 1158 void *cookie = NULL; 1159 zil_vdev_node_t *zv; 1160 lwb_t *nlwb; 1161 1162 ASSERT3S(spa_config_held(spa, SCL_STATE, RW_READER), !=, 0); 1163 1164 ASSERT(BP_GET_COMPRESS(zio->io_bp) == ZIO_COMPRESS_OFF); 1165 ASSERT(BP_GET_TYPE(zio->io_bp) == DMU_OT_INTENT_LOG); 1166 ASSERT(BP_GET_LEVEL(zio->io_bp) == 0); 1167 ASSERT(BP_GET_BYTEORDER(zio->io_bp) == ZFS_HOST_BYTEORDER); 1168 ASSERT(!BP_IS_GANG(zio->io_bp)); 1169 ASSERT(!BP_IS_HOLE(zio->io_bp)); 1170 ASSERT(BP_GET_FILL(zio->io_bp) == 0); 1171 1172 abd_put(zio->io_abd); 1173 1174 mutex_enter(&zilog->zl_lock); 1175 ASSERT3S(lwb->lwb_state, ==, LWB_STATE_ISSUED); 1176 lwb->lwb_state = LWB_STATE_WRITE_DONE; 1177 lwb->lwb_write_zio = NULL; 1178 nlwb = list_next(&zilog->zl_lwb_list, lwb); 1179 mutex_exit(&zilog->zl_lock); 1180 1181 if (avl_numnodes(t) == 0) 1182 return; 1183 1184 /* 1185 * If there was an IO error, we're not going to call zio_flush() 1186 * on these vdevs, so we simply empty the tree and free the 1187 * nodes. We avoid calling zio_flush() since there isn't any 1188 * good reason for doing so, after the lwb block failed to be 1189 * written out. 1190 */ 1191 if (zio->io_error != 0) { 1192 while ((zv = avl_destroy_nodes(t, &cookie)) != NULL) 1193 kmem_free(zv, sizeof (*zv)); 1194 return; 1195 } 1196 1197 /* 1198 * If this lwb does not have any threads waiting for it to 1199 * complete, we want to defer issuing the DKIOCFLUSHWRITECACHE 1200 * command to the vdevs written to by "this" lwb, and instead 1201 * rely on the "next" lwb to handle the DKIOCFLUSHWRITECACHE 1202 * command for those vdevs. Thus, we merge the vdev tree of 1203 * "this" lwb with the vdev tree of the "next" lwb in the list, 1204 * and assume the "next" lwb will handle flushing the vdevs (or 1205 * deferring the flush(s) again). 1206 * 1207 * This is a useful performance optimization, especially for 1208 * workloads with lots of async write activity and few sync 1209 * write and/or fsync activity, as it has the potential to 1210 * coalesce multiple flush commands to a vdev into one. 1211 */ 1212 if (list_head(&lwb->lwb_waiters) == NULL && nlwb != NULL) { 1213 zil_lwb_flush_defer(lwb, nlwb); 1214 ASSERT(avl_is_empty(&lwb->lwb_vdev_tree)); 1215 return; 1216 } 1217 1218 while ((zv = avl_destroy_nodes(t, &cookie)) != NULL) { 1219 vdev_t *vd = vdev_lookup_top(spa, zv->zv_vdev); 1220 if (vd != NULL) 1221 zio_flush(lwb->lwb_root_zio, vd); 1222 kmem_free(zv, sizeof (*zv)); 1223 } 1224} 1225 1226static void 1227zil_lwb_set_zio_dependency(zilog_t *zilog, lwb_t *lwb) 1228{ 1229 lwb_t *last_lwb_opened = zilog->zl_last_lwb_opened; 1230 1231 ASSERT(MUTEX_HELD(&zilog->zl_issuer_lock)); 1232 ASSERT(MUTEX_HELD(&zilog->zl_lock)); 1233 1234 /* 1235 * The zilog's "zl_last_lwb_opened" field is used to build the 1236 * lwb/zio dependency chain, which is used to preserve the 1237 * ordering of lwb completions that is required by the semantics 1238 * of the ZIL. Each new lwb zio becomes a parent of the 1239 * "previous" lwb zio, such that the new lwb's zio cannot 1240 * complete until the "previous" lwb's zio completes. 1241 * 1242 * This is required by the semantics of zil_commit(); the commit 1243 * waiters attached to the lwbs will be woken in the lwb zio's 1244 * completion callback, so this zio dependency graph ensures the 1245 * waiters are woken in the correct order (the same order the 1246 * lwbs were created). 1247 */ 1248 if (last_lwb_opened != NULL && 1249 last_lwb_opened->lwb_state != LWB_STATE_FLUSH_DONE) { 1250 ASSERT(last_lwb_opened->lwb_state == LWB_STATE_OPENED || 1251 last_lwb_opened->lwb_state == LWB_STATE_ISSUED || 1252 last_lwb_opened->lwb_state == LWB_STATE_WRITE_DONE); 1253 1254 ASSERT3P(last_lwb_opened->lwb_root_zio, !=, NULL); 1255 zio_add_child(lwb->lwb_root_zio, 1256 last_lwb_opened->lwb_root_zio); 1257 1258 /* 1259 * If the previous lwb's write hasn't already completed, 1260 * we also want to order the completion of the lwb write 1261 * zios (above, we only order the completion of the lwb 1262 * root zios). This is required because of how we can 1263 * defer the DKIOCFLUSHWRITECACHE commands for each lwb. 1264 * 1265 * When the DKIOCFLUSHWRITECACHE commands are defered, 1266 * the previous lwb will rely on this lwb to flush the 1267 * vdevs written to by that previous lwb. Thus, we need 1268 * to ensure this lwb doesn't issue the flush until 1269 * after the previous lwb's write completes. We ensure 1270 * this ordering by setting the zio parent/child 1271 * relationship here. 1272 * 1273 * Without this relationship on the lwb's write zio, 1274 * it's possible for this lwb's write to complete prior 1275 * to the previous lwb's write completing; and thus, the 1276 * vdevs for the previous lwb would be flushed prior to 1277 * that lwb's data being written to those vdevs (the 1278 * vdevs are flushed in the lwb write zio's completion 1279 * handler, zil_lwb_write_done()). 1280 */ 1281 if (last_lwb_opened->lwb_state != LWB_STATE_WRITE_DONE) { 1282 ASSERT(last_lwb_opened->lwb_state == LWB_STATE_OPENED || 1283 last_lwb_opened->lwb_state == LWB_STATE_ISSUED); 1284 1285 ASSERT3P(last_lwb_opened->lwb_write_zio, !=, NULL); 1286 zio_add_child(lwb->lwb_write_zio, 1287 last_lwb_opened->lwb_write_zio); 1288 } 1289 } 1290} 1291 1292 1293/* 1294 * This function's purpose is to "open" an lwb such that it is ready to 1295 * accept new itxs being committed to it. To do this, the lwb's zio 1296 * structures are created, and linked to the lwb. This function is 1297 * idempotent; if the passed in lwb has already been opened, this 1298 * function is essentially a no-op. 1299 */ 1300static void 1301zil_lwb_write_open(zilog_t *zilog, lwb_t *lwb) 1302{ 1303 zbookmark_phys_t zb; 1304 zio_priority_t prio; 1305 1306 ASSERT(MUTEX_HELD(&zilog->zl_issuer_lock)); 1307 ASSERT3P(lwb, !=, NULL); 1308 EQUIV(lwb->lwb_root_zio == NULL, lwb->lwb_state == LWB_STATE_CLOSED); 1309 EQUIV(lwb->lwb_root_zio != NULL, lwb->lwb_state == LWB_STATE_OPENED); 1310 1311 SET_BOOKMARK(&zb, lwb->lwb_blk.blk_cksum.zc_word[ZIL_ZC_OBJSET], 1312 ZB_ZIL_OBJECT, ZB_ZIL_LEVEL, 1313 lwb->lwb_blk.blk_cksum.zc_word[ZIL_ZC_SEQ]); 1314 1315 if (lwb->lwb_root_zio == NULL) { 1316 abd_t *lwb_abd = abd_get_from_buf(lwb->lwb_buf, 1317 BP_GET_LSIZE(&lwb->lwb_blk)); 1318 1319 if (!lwb->lwb_slog || zilog->zl_cur_used <= zil_slog_bulk) 1320 prio = ZIO_PRIORITY_SYNC_WRITE; 1321 else 1322 prio = ZIO_PRIORITY_ASYNC_WRITE; 1323 1324 lwb->lwb_root_zio = zio_root(zilog->zl_spa, 1325 zil_lwb_flush_vdevs_done, lwb, ZIO_FLAG_CANFAIL); 1326 ASSERT3P(lwb->lwb_root_zio, !=, NULL); 1327 1328 lwb->lwb_write_zio = zio_rewrite(lwb->lwb_root_zio, 1329 zilog->zl_spa, 0, &lwb->lwb_blk, lwb_abd, 1330 BP_GET_LSIZE(&lwb->lwb_blk), zil_lwb_write_done, lwb, 1331 prio, ZIO_FLAG_CANFAIL | ZIO_FLAG_DONT_PROPAGATE, &zb); 1332 ASSERT3P(lwb->lwb_write_zio, !=, NULL); 1333 1334 lwb->lwb_state = LWB_STATE_OPENED; 1335 1336 mutex_enter(&zilog->zl_lock); 1337 zil_lwb_set_zio_dependency(zilog, lwb); 1338 zilog->zl_last_lwb_opened = lwb; 1339 mutex_exit(&zilog->zl_lock); 1340 } 1341 1342 ASSERT3P(lwb->lwb_root_zio, !=, NULL); 1343 ASSERT3P(lwb->lwb_write_zio, !=, NULL); 1344 ASSERT3S(lwb->lwb_state, ==, LWB_STATE_OPENED); 1345} 1346 1347/* 1348 * Define a limited set of intent log block sizes. 1349 * 1350 * These must be a multiple of 4KB. Note only the amount used (again 1351 * aligned to 4KB) actually gets written. However, we can't always just 1352 * allocate SPA_OLD_MAXBLOCKSIZE as the slog space could be exhausted. 1353 */ 1354struct { 1355 uint64_t limit; 1356 uint64_t blksz; 1357} zil_block_buckets[] = { 1358 { 4096, 4096 }, /* non TX_WRITE */ 1359 { 8192 + 4096, 8192 + 4096 }, /* database */ 1360 { 32768 + 4096, 32768 + 4096 }, /* NFS writes */ 1361 { 65536 + 4096, 65536 + 4096 }, /* 64KB writes */ 1362 { 131072, 131072 }, /* < 128KB writes */ 1363 { 131072 + 4096, 65536 + 4096 }, /* 128KB writes */ 1364 { UINT64_MAX, SPA_OLD_MAXBLOCKSIZE}, /* > 128KB writes */ 1365}; 1366 1367/* 1368 * Maximum block size used by the ZIL. This is picked up when the ZIL is 1369 * initialized. Otherwise this should not be used directly; see 1370 * zl_max_block_size instead. 1371 */ 1372int zil_maxblocksize = SPA_OLD_MAXBLOCKSIZE; 1373SYSCTL_INT(_vfs_zfs, OID_AUTO, zil_maxblocksize, CTLFLAG_RWTUN, 1374 &zil_maxblocksize, 0, "Limit in bytes of ZIL log block size"); 1375 1376/* 1377 * Start a log block write and advance to the next log block. 1378 * Calls are serialized. 1379 */ 1380static lwb_t * 1381zil_lwb_write_issue(zilog_t *zilog, lwb_t *lwb) 1382{ 1383 lwb_t *nlwb = NULL; 1384 zil_chain_t *zilc; 1385 spa_t *spa = zilog->zl_spa; 1386 blkptr_t *bp; 1387 dmu_tx_t *tx; 1388 uint64_t txg; 1389 uint64_t zil_blksz, wsz; 1390 int i, error; 1391 boolean_t slog; 1392 1393 ASSERT(MUTEX_HELD(&zilog->zl_issuer_lock)); 1394 ASSERT3P(lwb->lwb_root_zio, !=, NULL); 1395 ASSERT3P(lwb->lwb_write_zio, !=, NULL); 1396 ASSERT3S(lwb->lwb_state, ==, LWB_STATE_OPENED); 1397 1398 if (BP_GET_CHECKSUM(&lwb->lwb_blk) == ZIO_CHECKSUM_ZILOG2) { 1399 zilc = (zil_chain_t *)lwb->lwb_buf; 1400 bp = &zilc->zc_next_blk; 1401 } else { 1402 zilc = (zil_chain_t *)(lwb->lwb_buf + lwb->lwb_sz); 1403 bp = &zilc->zc_next_blk; 1404 } 1405 1406 ASSERT(lwb->lwb_nused <= lwb->lwb_sz); 1407 1408 /* 1409 * Allocate the next block and save its address in this block 1410 * before writing it in order to establish the log chain. 1411 * Note that if the allocation of nlwb synced before we wrote 1412 * the block that points at it (lwb), we'd leak it if we crashed. 1413 * Therefore, we don't do dmu_tx_commit() until zil_lwb_write_done(). 1414 * We dirty the dataset to ensure that zil_sync() will be called 1415 * to clean up in the event of allocation failure or I/O failure. 1416 */ 1417 1418 tx = dmu_tx_create(zilog->zl_os); 1419 1420 /* 1421 * Since we are not going to create any new dirty data, and we 1422 * can even help with clearing the existing dirty data, we 1423 * should not be subject to the dirty data based delays. We 1424 * use TXG_NOTHROTTLE to bypass the delay mechanism. 1425 */ 1426 VERIFY0(dmu_tx_assign(tx, TXG_WAIT | TXG_NOTHROTTLE)); 1427 1428 dsl_dataset_dirty(dmu_objset_ds(zilog->zl_os), tx); 1429 txg = dmu_tx_get_txg(tx); 1430 1431 lwb->lwb_tx = tx; 1432 1433 /* 1434 * Log blocks are pre-allocated. Here we select the size of the next 1435 * block, based on size used in the last block. 1436 * - first find the smallest bucket that will fit the block from a 1437 * limited set of block sizes. This is because it's faster to write 1438 * blocks allocated from the same metaslab as they are adjacent or 1439 * close. 1440 * - next find the maximum from the new suggested size and an array of 1441 * previous sizes. This lessens a picket fence effect of wrongly 1442 * guesssing the size if we have a stream of say 2k, 64k, 2k, 64k 1443 * requests. 1444 * 1445 * Note we only write what is used, but we can't just allocate 1446 * the maximum block size because we can exhaust the available 1447 * pool log space. 1448 */ 1449 zil_blksz = zilog->zl_cur_used + sizeof (zil_chain_t); 1450 for (i = 0; zil_blksz > zil_block_buckets[i].limit; i++) 1451 continue; 1452 zil_blksz = MIN(zil_block_buckets[i].blksz, zilog->zl_max_block_size); 1453 zilog->zl_prev_blks[zilog->zl_prev_rotor] = zil_blksz; 1454 for (i = 0; i < ZIL_PREV_BLKS; i++) 1455 zil_blksz = MAX(zil_blksz, zilog->zl_prev_blks[i]); 1456 zilog->zl_prev_rotor = (zilog->zl_prev_rotor + 1) & (ZIL_PREV_BLKS - 1); 1457 1458 BP_ZERO(bp); 1459 1460 /* pass the old blkptr in order to spread log blocks across devs */ 1461 error = zio_alloc_zil(spa, zilog->zl_os->os_dsl_dataset->ds_object, 1462 txg, bp, &lwb->lwb_blk, zil_blksz, &slog); 1463 if (error == 0) { 1464 ASSERT3U(bp->blk_birth, ==, txg); 1465 bp->blk_cksum = lwb->lwb_blk.blk_cksum; 1466 bp->blk_cksum.zc_word[ZIL_ZC_SEQ]++; 1467 1468 /* 1469 * Allocate a new log write block (lwb). 1470 */ 1471 nlwb = zil_alloc_lwb(zilog, bp, slog, txg); 1472 } 1473 1474 if (BP_GET_CHECKSUM(&lwb->lwb_blk) == ZIO_CHECKSUM_ZILOG2) { 1475 /* For Slim ZIL only write what is used. */ 1476 wsz = P2ROUNDUP_TYPED(lwb->lwb_nused, ZIL_MIN_BLKSZ, uint64_t); 1477 ASSERT3U(wsz, <=, lwb->lwb_sz); 1478 zio_shrink(lwb->lwb_write_zio, wsz); 1479 1480 } else { 1481 wsz = lwb->lwb_sz; 1482 } 1483 1484 zilc->zc_pad = 0; 1485 zilc->zc_nused = lwb->lwb_nused; 1486 zilc->zc_eck.zec_cksum = lwb->lwb_blk.blk_cksum; 1487 1488 /* 1489 * clear unused data for security 1490 */ 1491 bzero(lwb->lwb_buf + lwb->lwb_nused, wsz - lwb->lwb_nused); 1492 1493 spa_config_enter(zilog->zl_spa, SCL_STATE, lwb, RW_READER); 1494 1495 zil_lwb_add_block(lwb, &lwb->lwb_blk); 1496 lwb->lwb_issued_timestamp = gethrtime(); 1497 lwb->lwb_state = LWB_STATE_ISSUED; 1498 1499 zio_nowait(lwb->lwb_root_zio); 1500 zio_nowait(lwb->lwb_write_zio); 1501 1502 /* 1503 * If there was an allocation failure then nlwb will be null which 1504 * forces a txg_wait_synced(). 1505 */ 1506 return (nlwb); 1507} 1508 1509/* 1510 * Maximum amount of write data that can be put into single log block. 1511 */ 1512uint64_t 1513zil_max_log_data(zilog_t *zilog) 1514{ 1515 return (zilog->zl_max_block_size - 1516 sizeof (zil_chain_t) - sizeof (lr_write_t)); 1517} 1518 1519/* 1520 * Maximum amount of log space we agree to waste to reduce number of 1521 * WR_NEED_COPY chunks to reduce zl_get_data() overhead (~12%). 1522 */ 1523static inline uint64_t 1524zil_max_waste_space(zilog_t *zilog) 1525{ 1526 return (zil_max_log_data(zilog) / 8); 1527} 1528 1529/* 1530 * Maximum amount of write data for WR_COPIED. For correctness, consumers 1531 * must fall back to WR_NEED_COPY if we can't fit the entire record into one 1532 * maximum sized log block, because each WR_COPIED record must fit in a 1533 * single log block. For space efficiency, we want to fit two records into a 1534 * max-sized log block. 1535 */ 1536uint64_t 1537zil_max_copied_data(zilog_t *zilog) 1538{ 1539 return ((zilog->zl_max_block_size - sizeof (zil_chain_t)) / 2 - 1540 sizeof (lr_write_t)); 1541} 1542 1543static lwb_t * 1544zil_lwb_commit(zilog_t *zilog, itx_t *itx, lwb_t *lwb) 1545{ 1546 lr_t *lrcb, *lrc; 1547 lr_write_t *lrwb, *lrw; 1548 char *lr_buf; 1549 uint64_t dlen, dnow, lwb_sp, reclen, txg, max_log_data; 1550 1551 ASSERT(MUTEX_HELD(&zilog->zl_issuer_lock)); 1552 ASSERT3P(lwb, !=, NULL); 1553 ASSERT3P(lwb->lwb_buf, !=, NULL); 1554 1555 zil_lwb_write_open(zilog, lwb); 1556 1557 lrc = &itx->itx_lr; 1558 lrw = (lr_write_t *)lrc; 1559 1560 /* 1561 * A commit itx doesn't represent any on-disk state; instead 1562 * it's simply used as a place holder on the commit list, and 1563 * provides a mechanism for attaching a "commit waiter" onto the 1564 * correct lwb (such that the waiter can be signalled upon 1565 * completion of that lwb). Thus, we don't process this itx's 1566 * log record if it's a commit itx (these itx's don't have log 1567 * records), and instead link the itx's waiter onto the lwb's 1568 * list of waiters. 1569 * 1570 * For more details, see the comment above zil_commit(). 1571 */ 1572 if (lrc->lrc_txtype == TX_COMMIT) { 1573 mutex_enter(&zilog->zl_lock); 1574 zil_commit_waiter_link_lwb(itx->itx_private, lwb); 1575 itx->itx_private = NULL; 1576 mutex_exit(&zilog->zl_lock); 1577 return (lwb); 1578 } 1579 1580 if (lrc->lrc_txtype == TX_WRITE && itx->itx_wr_state == WR_NEED_COPY) { 1581 dlen = P2ROUNDUP_TYPED( 1582 lrw->lr_length, sizeof (uint64_t), uint64_t); 1583 } else { 1584 dlen = 0; 1585 } 1586 reclen = lrc->lrc_reclen; 1587 zilog->zl_cur_used += (reclen + dlen); 1588 txg = lrc->lrc_txg; 1589 1590 ASSERT3U(zilog->zl_cur_used, <, UINT64_MAX - (reclen + dlen)); 1591 1592cont: 1593 /* 1594 * If this record won't fit in the current log block, start a new one. 1595 * For WR_NEED_COPY optimize layout for minimal number of chunks. 1596 */ 1597 lwb_sp = lwb->lwb_sz - lwb->lwb_nused; 1598 max_log_data = zil_max_log_data(zilog); 1599 if (reclen > lwb_sp || (reclen + dlen > lwb_sp && 1600 lwb_sp < zil_max_waste_space(zilog) && 1601 (dlen % max_log_data == 0 || 1602 lwb_sp < reclen + dlen % max_log_data))) { 1603 lwb = zil_lwb_write_issue(zilog, lwb); 1604 if (lwb == NULL) 1605 return (NULL); 1606 zil_lwb_write_open(zilog, lwb); 1607 ASSERT(LWB_EMPTY(lwb)); 1608 lwb_sp = lwb->lwb_sz - lwb->lwb_nused; 1609 1610 /* 1611 * There must be enough space in the new, empty log block to 1612 * hold reclen. For WR_COPIED, we need to fit the whole 1613 * record in one block, and reclen is the header size + the 1614 * data size. For WR_NEED_COPY, we can create multiple 1615 * records, splitting the data into multiple blocks, so we 1616 * only need to fit one word of data per block; in this case 1617 * reclen is just the header size (no data). 1618 */ 1619 ASSERT3U(reclen + MIN(dlen, sizeof (uint64_t)), <=, lwb_sp); 1620 } 1621 1622 dnow = MIN(dlen, lwb_sp - reclen); 1623 lr_buf = lwb->lwb_buf + lwb->lwb_nused; 1624 bcopy(lrc, lr_buf, reclen); 1625 lrcb = (lr_t *)lr_buf; /* Like lrc, but inside lwb. */ 1626 lrwb = (lr_write_t *)lrcb; /* Like lrw, but inside lwb. */ 1627 1628 /* 1629 * If it's a write, fetch the data or get its blkptr as appropriate. 1630 */ 1631 if (lrc->lrc_txtype == TX_WRITE) { 1632 if (txg > spa_freeze_txg(zilog->zl_spa)) 1633 txg_wait_synced(zilog->zl_dmu_pool, txg); 1634 if (itx->itx_wr_state != WR_COPIED) { 1635 char *dbuf; 1636 int error; 1637 1638 if (itx->itx_wr_state == WR_NEED_COPY) { 1639 dbuf = lr_buf + reclen; 1640 lrcb->lrc_reclen += dnow; 1641 if (lrwb->lr_length > dnow) 1642 lrwb->lr_length = dnow; 1643 lrw->lr_offset += dnow; 1644 lrw->lr_length -= dnow; 1645 } else { 1646 ASSERT(itx->itx_wr_state == WR_INDIRECT); 1647 dbuf = NULL; 1648 } 1649 1650 /* 1651 * We pass in the "lwb_write_zio" rather than 1652 * "lwb_root_zio" so that the "lwb_write_zio" 1653 * becomes the parent of any zio's created by 1654 * the "zl_get_data" callback. The vdevs are 1655 * flushed after the "lwb_write_zio" completes, 1656 * so we want to make sure that completion 1657 * callback waits for these additional zio's, 1658 * such that the vdevs used by those zio's will 1659 * be included in the lwb's vdev tree, and those 1660 * vdevs will be properly flushed. If we passed 1661 * in "lwb_root_zio" here, then these additional 1662 * vdevs may not be flushed; e.g. if these zio's 1663 * completed after "lwb_write_zio" completed. 1664 */ 1665 error = zilog->zl_get_data(itx->itx_private, 1666 lrwb, dbuf, lwb, lwb->lwb_write_zio); 1667 1668 if (error == EIO) { 1669 txg_wait_synced(zilog->zl_dmu_pool, txg); 1670 return (lwb); 1671 } 1672 if (error != 0) { 1673 ASSERT(error == ENOENT || error == EEXIST || 1674 error == EALREADY); 1675 return (lwb); 1676 } 1677 } 1678 } 1679 1680 /* 1681 * We're actually making an entry, so update lrc_seq to be the 1682 * log record sequence number. Note that this is generally not 1683 * equal to the itx sequence number because not all transactions 1684 * are synchronous, and sometimes spa_sync() gets there first. 1685 */ 1686 lrcb->lrc_seq = ++zilog->zl_lr_seq; 1687 lwb->lwb_nused += reclen + dnow; 1688 1689 zil_lwb_add_txg(lwb, txg); 1690 1691 ASSERT3U(lwb->lwb_nused, <=, lwb->lwb_sz); 1692 ASSERT0(P2PHASE(lwb->lwb_nused, sizeof (uint64_t))); 1693 1694 dlen -= dnow; 1695 if (dlen > 0) { 1696 zilog->zl_cur_used += reclen; 1697 goto cont; 1698 } 1699 1700 return (lwb); 1701} 1702 1703itx_t * 1704zil_itx_create(uint64_t txtype, size_t lrsize) 1705{ 1706 itx_t *itx; 1707 1708 lrsize = P2ROUNDUP_TYPED(lrsize, sizeof (uint64_t), size_t); 1709 1710 itx = kmem_alloc(offsetof(itx_t, itx_lr) + lrsize, KM_SLEEP); 1711 itx->itx_lr.lrc_txtype = txtype; 1712 itx->itx_lr.lrc_reclen = lrsize; 1713 itx->itx_lr.lrc_seq = 0; /* defensive */ 1714 itx->itx_sync = B_TRUE; /* default is synchronous */ 1715 1716 return (itx); 1717} 1718 1719void 1720zil_itx_destroy(itx_t *itx) 1721{ 1722 kmem_free(itx, offsetof(itx_t, itx_lr) + itx->itx_lr.lrc_reclen); 1723} 1724 1725/* 1726 * Free up the sync and async itxs. The itxs_t has already been detached 1727 * so no locks are needed. 1728 */ 1729static void 1730zil_itxg_clean(itxs_t *itxs) 1731{ 1732 itx_t *itx; 1733 list_t *list; 1734 avl_tree_t *t; 1735 void *cookie; 1736 itx_async_node_t *ian; 1737 1738 list = &itxs->i_sync_list; 1739 while ((itx = list_head(list)) != NULL) { 1740 /* 1741 * In the general case, commit itxs will not be found 1742 * here, as they'll be committed to an lwb via 1743 * zil_lwb_commit(), and free'd in that function. Having 1744 * said that, it is still possible for commit itxs to be 1745 * found here, due to the following race: 1746 * 1747 * - a thread calls zil_commit() which assigns the 1748 * commit itx to a per-txg i_sync_list 1749 * - zil_itxg_clean() is called (e.g. via spa_sync()) 1750 * while the waiter is still on the i_sync_list 1751 * 1752 * There's nothing to prevent syncing the txg while the 1753 * waiter is on the i_sync_list. This normally doesn't 1754 * happen because spa_sync() is slower than zil_commit(), 1755 * but if zil_commit() calls txg_wait_synced() (e.g. 1756 * because zil_create() or zil_commit_writer_stall() is 1757 * called) we will hit this case. 1758 */ 1759 if (itx->itx_lr.lrc_txtype == TX_COMMIT) 1760 zil_commit_waiter_skip(itx->itx_private); 1761 1762 list_remove(list, itx); 1763 zil_itx_destroy(itx); 1764 } 1765 1766 cookie = NULL; 1767 t = &itxs->i_async_tree; 1768 while ((ian = avl_destroy_nodes(t, &cookie)) != NULL) { 1769 list = &ian->ia_list; 1770 while ((itx = list_head(list)) != NULL) { 1771 list_remove(list, itx); 1772 /* commit itxs should never be on the async lists. */ 1773 ASSERT3U(itx->itx_lr.lrc_txtype, !=, TX_COMMIT); 1774 zil_itx_destroy(itx); 1775 } 1776 list_destroy(list); 1777 kmem_free(ian, sizeof (itx_async_node_t)); 1778 } 1779 avl_destroy(t); 1780 1781 kmem_free(itxs, sizeof (itxs_t)); 1782} 1783 1784static int 1785zil_aitx_compare(const void *x1, const void *x2) 1786{ 1787 const uint64_t o1 = ((itx_async_node_t *)x1)->ia_foid; 1788 const uint64_t o2 = ((itx_async_node_t *)x2)->ia_foid; 1789 1790 return (AVL_CMP(o1, o2)); 1791} 1792 1793/* 1794 * Remove all async itx with the given oid. 1795 */ 1796static void 1797zil_remove_async(zilog_t *zilog, uint64_t oid) 1798{ 1799 uint64_t otxg, txg; 1800 itx_async_node_t *ian; 1801 avl_tree_t *t; 1802 avl_index_t where; 1803 list_t clean_list; 1804 itx_t *itx; 1805 1806 ASSERT(oid != 0); 1807 list_create(&clean_list, sizeof (itx_t), offsetof(itx_t, itx_node)); 1808 1809 if (spa_freeze_txg(zilog->zl_spa) != UINT64_MAX) /* ziltest support */ 1810 otxg = ZILTEST_TXG; 1811 else 1812 otxg = spa_last_synced_txg(zilog->zl_spa) + 1; 1813 1814 for (txg = otxg; txg < (otxg + TXG_CONCURRENT_STATES); txg++) { 1815 itxg_t *itxg = &zilog->zl_itxg[txg & TXG_MASK]; 1816 1817 mutex_enter(&itxg->itxg_lock); 1818 if (itxg->itxg_txg != txg) { 1819 mutex_exit(&itxg->itxg_lock); 1820 continue; 1821 } 1822 1823 /* 1824 * Locate the object node and append its list. 1825 */ 1826 t = &itxg->itxg_itxs->i_async_tree; 1827 ian = avl_find(t, &oid, &where); 1828 if (ian != NULL) 1829 list_move_tail(&clean_list, &ian->ia_list); 1830 mutex_exit(&itxg->itxg_lock); 1831 } 1832 while ((itx = list_head(&clean_list)) != NULL) { 1833 list_remove(&clean_list, itx); 1834 /* commit itxs should never be on the async lists. */ 1835 ASSERT3U(itx->itx_lr.lrc_txtype, !=, TX_COMMIT); 1836 zil_itx_destroy(itx); 1837 } 1838 list_destroy(&clean_list); 1839} 1840 1841void 1842zil_itx_assign(zilog_t *zilog, itx_t *itx, dmu_tx_t *tx) 1843{ 1844 uint64_t txg; 1845 itxg_t *itxg; 1846 itxs_t *itxs, *clean = NULL; 1847 1848 /* 1849 * Object ids can be re-instantiated in the next txg so 1850 * remove any async transactions to avoid future leaks. 1851 * This can happen if a fsync occurs on the re-instantiated 1852 * object for a WR_INDIRECT or WR_NEED_COPY write, which gets 1853 * the new file data and flushes a write record for the old object. 1854 */ 1855 if ((itx->itx_lr.lrc_txtype & ~TX_CI) == TX_REMOVE) 1856 zil_remove_async(zilog, itx->itx_oid); 1857 1858 /* 1859 * Ensure the data of a renamed file is committed before the rename. 1860 */ 1861 if ((itx->itx_lr.lrc_txtype & ~TX_CI) == TX_RENAME) 1862 zil_async_to_sync(zilog, itx->itx_oid); 1863 1864 if (spa_freeze_txg(zilog->zl_spa) != UINT64_MAX) 1865 txg = ZILTEST_TXG; 1866 else 1867 txg = dmu_tx_get_txg(tx); 1868 1869 itxg = &zilog->zl_itxg[txg & TXG_MASK]; 1870 mutex_enter(&itxg->itxg_lock); 1871 itxs = itxg->itxg_itxs; 1872 if (itxg->itxg_txg != txg) { 1873 if (itxs != NULL) { 1874 /* 1875 * The zil_clean callback hasn't got around to cleaning 1876 * this itxg. Save the itxs for release below. 1877 * This should be rare. 1878 */ 1879 zfs_dbgmsg("zil_itx_assign: missed itx cleanup for " 1880 "txg %llu", itxg->itxg_txg); 1881 clean = itxg->itxg_itxs; 1882 } 1883 itxg->itxg_txg = txg; 1884 itxs = itxg->itxg_itxs = kmem_zalloc(sizeof (itxs_t), KM_SLEEP); 1885 1886 list_create(&itxs->i_sync_list, sizeof (itx_t), 1887 offsetof(itx_t, itx_node)); 1888 avl_create(&itxs->i_async_tree, zil_aitx_compare, 1889 sizeof (itx_async_node_t), 1890 offsetof(itx_async_node_t, ia_node)); 1891 } 1892 if (itx->itx_sync) { 1893 list_insert_tail(&itxs->i_sync_list, itx); 1894 } else { 1895 avl_tree_t *t = &itxs->i_async_tree; 1896 uint64_t foid = 1897 LR_FOID_GET_OBJ(((lr_ooo_t *)&itx->itx_lr)->lr_foid); 1898 itx_async_node_t *ian; 1899 avl_index_t where; 1900 1901 ian = avl_find(t, &foid, &where); 1902 if (ian == NULL) { 1903 ian = kmem_alloc(sizeof (itx_async_node_t), KM_SLEEP); 1904 list_create(&ian->ia_list, sizeof (itx_t), 1905 offsetof(itx_t, itx_node)); 1906 ian->ia_foid = foid; 1907 avl_insert(t, ian, where); 1908 } 1909 list_insert_tail(&ian->ia_list, itx); 1910 } 1911 1912 itx->itx_lr.lrc_txg = dmu_tx_get_txg(tx); 1913 1914 /* 1915 * We don't want to dirty the ZIL using ZILTEST_TXG, because 1916 * zil_clean() will never be called using ZILTEST_TXG. Thus, we 1917 * need to be careful to always dirty the ZIL using the "real" 1918 * TXG (not itxg_txg) even when the SPA is frozen. 1919 */ 1920 zilog_dirty(zilog, dmu_tx_get_txg(tx)); 1921 mutex_exit(&itxg->itxg_lock); 1922 1923 /* Release the old itxs now we've dropped the lock */ 1924 if (clean != NULL) 1925 zil_itxg_clean(clean); 1926} 1927 1928/* 1929 * If there are any in-memory intent log transactions which have now been 1930 * synced then start up a taskq to free them. We should only do this after we 1931 * have written out the uberblocks (i.e. txg has been comitted) so that 1932 * don't inadvertently clean out in-memory log records that would be required 1933 * by zil_commit(). 1934 */ 1935void 1936zil_clean(zilog_t *zilog, uint64_t synced_txg) 1937{ 1938 itxg_t *itxg = &zilog->zl_itxg[synced_txg & TXG_MASK]; 1939 itxs_t *clean_me; 1940 1941 ASSERT3U(synced_txg, <, ZILTEST_TXG); 1942 1943 mutex_enter(&itxg->itxg_lock); 1944 if (itxg->itxg_itxs == NULL || itxg->itxg_txg == ZILTEST_TXG) { 1945 mutex_exit(&itxg->itxg_lock); 1946 return; 1947 } 1948 ASSERT3U(itxg->itxg_txg, <=, synced_txg); 1949 ASSERT3U(itxg->itxg_txg, !=, 0); 1950 clean_me = itxg->itxg_itxs; 1951 itxg->itxg_itxs = NULL; 1952 itxg->itxg_txg = 0; 1953 mutex_exit(&itxg->itxg_lock); 1954 /* 1955 * Preferably start a task queue to free up the old itxs but 1956 * if taskq_dispatch can't allocate resources to do that then 1957 * free it in-line. This should be rare. Note, using TQ_SLEEP 1958 * created a bad performance problem. 1959 */ 1960 ASSERT3P(zilog->zl_dmu_pool, !=, NULL); 1961 ASSERT3P(zilog->zl_dmu_pool->dp_zil_clean_taskq, !=, NULL); 1962 if (taskq_dispatch(zilog->zl_dmu_pool->dp_zil_clean_taskq, 1963 (void (*)(void *))zil_itxg_clean, clean_me, TQ_NOSLEEP) == 0) 1964 zil_itxg_clean(clean_me); 1965} 1966 1967/* 1968 * This function will traverse the queue of itxs that need to be 1969 * committed, and move them onto the ZIL's zl_itx_commit_list. 1970 */ 1971static void 1972zil_get_commit_list(zilog_t *zilog) 1973{ 1974 uint64_t otxg, txg; 1975 list_t *commit_list = &zilog->zl_itx_commit_list; 1976 1977 ASSERT(MUTEX_HELD(&zilog->zl_issuer_lock)); 1978 1979 if (spa_freeze_txg(zilog->zl_spa) != UINT64_MAX) /* ziltest support */ 1980 otxg = ZILTEST_TXG; 1981 else 1982 otxg = spa_last_synced_txg(zilog->zl_spa) + 1; 1983 1984 /* 1985 * This is inherently racy, since there is nothing to prevent 1986 * the last synced txg from changing. That's okay since we'll 1987 * only commit things in the future. 1988 */ 1989 for (txg = otxg; txg < (otxg + TXG_CONCURRENT_STATES); txg++) { 1990 itxg_t *itxg = &zilog->zl_itxg[txg & TXG_MASK]; 1991 1992 mutex_enter(&itxg->itxg_lock); 1993 if (itxg->itxg_txg != txg) { 1994 mutex_exit(&itxg->itxg_lock); 1995 continue; 1996 } 1997 1998 /* 1999 * If we're adding itx records to the zl_itx_commit_list, 2000 * then the zil better be dirty in this "txg". We can assert 2001 * that here since we're holding the itxg_lock which will 2002 * prevent spa_sync from cleaning it. Once we add the itxs 2003 * to the zl_itx_commit_list we must commit it to disk even 2004 * if it's unnecessary (i.e. the txg was synced). 2005 */ 2006 ASSERT(zilog_is_dirty_in_txg(zilog, txg) || 2007 spa_freeze_txg(zilog->zl_spa) != UINT64_MAX); 2008 list_move_tail(commit_list, &itxg->itxg_itxs->i_sync_list); 2009 2010 mutex_exit(&itxg->itxg_lock); 2011 } 2012} 2013 2014/* 2015 * Move the async itxs for a specified object to commit into sync lists. 2016 */ 2017void 2018zil_async_to_sync(zilog_t *zilog, uint64_t foid) 2019{ 2020 uint64_t otxg, txg; 2021 itx_async_node_t *ian; 2022 avl_tree_t *t; 2023 avl_index_t where; 2024 2025 if (spa_freeze_txg(zilog->zl_spa) != UINT64_MAX) /* ziltest support */ 2026 otxg = ZILTEST_TXG; 2027 else 2028 otxg = spa_last_synced_txg(zilog->zl_spa) + 1; 2029 2030 /* 2031 * This is inherently racy, since there is nothing to prevent 2032 * the last synced txg from changing. 2033 */ 2034 for (txg = otxg; txg < (otxg + TXG_CONCURRENT_STATES); txg++) { 2035 itxg_t *itxg = &zilog->zl_itxg[txg & TXG_MASK]; 2036 2037 mutex_enter(&itxg->itxg_lock); 2038 if (itxg->itxg_txg != txg) { 2039 mutex_exit(&itxg->itxg_lock); 2040 continue; 2041 } 2042 2043 /* 2044 * If a foid is specified then find that node and append its 2045 * list. Otherwise walk the tree appending all the lists 2046 * to the sync list. We add to the end rather than the 2047 * beginning to ensure the create has happened. 2048 */ 2049 t = &itxg->itxg_itxs->i_async_tree; 2050 if (foid != 0) { 2051 ian = avl_find(t, &foid, &where); 2052 if (ian != NULL) { 2053 list_move_tail(&itxg->itxg_itxs->i_sync_list, 2054 &ian->ia_list); 2055 } 2056 } else { 2057 void *cookie = NULL; 2058 2059 while ((ian = avl_destroy_nodes(t, &cookie)) != NULL) { 2060 list_move_tail(&itxg->itxg_itxs->i_sync_list, 2061 &ian->ia_list); 2062 list_destroy(&ian->ia_list); 2063 kmem_free(ian, sizeof (itx_async_node_t)); 2064 } 2065 } 2066 mutex_exit(&itxg->itxg_lock); 2067 } 2068} 2069 2070/* 2071 * This function will prune commit itxs that are at the head of the 2072 * commit list (it won't prune past the first non-commit itx), and 2073 * either: a) attach them to the last lwb that's still pending 2074 * completion, or b) skip them altogether. 2075 * 2076 * This is used as a performance optimization to prevent commit itxs 2077 * from generating new lwbs when it's unnecessary to do so. 2078 */ 2079static void 2080zil_prune_commit_list(zilog_t *zilog) 2081{ 2082 itx_t *itx; 2083 2084 ASSERT(MUTEX_HELD(&zilog->zl_issuer_lock)); 2085 2086 while (itx = list_head(&zilog->zl_itx_commit_list)) { 2087 lr_t *lrc = &itx->itx_lr; 2088 if (lrc->lrc_txtype != TX_COMMIT) 2089 break; 2090 2091 mutex_enter(&zilog->zl_lock); 2092 2093 lwb_t *last_lwb = zilog->zl_last_lwb_opened; 2094 if (last_lwb == NULL || 2095 last_lwb->lwb_state == LWB_STATE_FLUSH_DONE) { 2096 /* 2097 * All of the itxs this waiter was waiting on 2098 * must have already completed (or there were 2099 * never any itx's for it to wait on), so it's 2100 * safe to skip this waiter and mark it done. 2101 */ 2102 zil_commit_waiter_skip(itx->itx_private); 2103 } else { 2104 zil_commit_waiter_link_lwb(itx->itx_private, last_lwb); 2105 itx->itx_private = NULL; 2106 } 2107 2108 mutex_exit(&zilog->zl_lock); 2109 2110 list_remove(&zilog->zl_itx_commit_list, itx); 2111 zil_itx_destroy(itx); 2112 } 2113 2114 IMPLY(itx != NULL, itx->itx_lr.lrc_txtype != TX_COMMIT); 2115} 2116 2117static void 2118zil_commit_writer_stall(zilog_t *zilog) 2119{ 2120 /* 2121 * When zio_alloc_zil() fails to allocate the next lwb block on 2122 * disk, we must call txg_wait_synced() to ensure all of the 2123 * lwbs in the zilog's zl_lwb_list are synced and then freed (in 2124 * zil_sync()), such that any subsequent ZIL writer (i.e. a call 2125 * to zil_process_commit_list()) will have to call zil_create(), 2126 * and start a new ZIL chain. 2127 * 2128 * Since zil_alloc_zil() failed, the lwb that was previously 2129 * issued does not have a pointer to the "next" lwb on disk. 2130 * Thus, if another ZIL writer thread was to allocate the "next" 2131 * on-disk lwb, that block could be leaked in the event of a 2132 * crash (because the previous lwb on-disk would not point to 2133 * it). 2134 * 2135 * We must hold the zilog's zl_issuer_lock while we do this, to 2136 * ensure no new threads enter zil_process_commit_list() until 2137 * all lwb's in the zl_lwb_list have been synced and freed 2138 * (which is achieved via the txg_wait_synced() call). 2139 */ 2140 ASSERT(MUTEX_HELD(&zilog->zl_issuer_lock)); 2141 txg_wait_synced(zilog->zl_dmu_pool, 0); 2142 ASSERT3P(list_tail(&zilog->zl_lwb_list), ==, NULL); 2143} 2144 2145/* 2146 * This function will traverse the commit list, creating new lwbs as 2147 * needed, and committing the itxs from the commit list to these newly 2148 * created lwbs. Additionally, as a new lwb is created, the previous 2149 * lwb will be issued to the zio layer to be written to disk. 2150 */ 2151static void 2152zil_process_commit_list(zilog_t *zilog) 2153{ 2154 spa_t *spa = zilog->zl_spa; 2155 list_t nolwb_waiters; 2156 lwb_t *lwb; 2157 itx_t *itx; 2158 2159 ASSERT(MUTEX_HELD(&zilog->zl_issuer_lock)); 2160 2161 /* 2162 * Return if there's nothing to commit before we dirty the fs by 2163 * calling zil_create(). 2164 */ 2165 if (list_head(&zilog->zl_itx_commit_list) == NULL) 2166 return; 2167 2168 list_create(&nolwb_waiters, sizeof (zil_commit_waiter_t), 2169 offsetof(zil_commit_waiter_t, zcw_node)); 2170 2171 lwb = list_tail(&zilog->zl_lwb_list); 2172 if (lwb == NULL) { 2173 lwb = zil_create(zilog); 2174 } else { 2175 ASSERT3S(lwb->lwb_state, !=, LWB_STATE_ISSUED); 2176 ASSERT3S(lwb->lwb_state, !=, LWB_STATE_WRITE_DONE); 2177 ASSERT3S(lwb->lwb_state, !=, LWB_STATE_FLUSH_DONE); 2178 } 2179 2180 while (itx = list_head(&zilog->zl_itx_commit_list)) { 2181 lr_t *lrc = &itx->itx_lr; 2182 uint64_t txg = lrc->lrc_txg; 2183 2184 ASSERT3U(txg, !=, 0); 2185 2186 if (lrc->lrc_txtype == TX_COMMIT) { 2187 DTRACE_PROBE2(zil__process__commit__itx, 2188 zilog_t *, zilog, itx_t *, itx); 2189 } else { 2190 DTRACE_PROBE2(zil__process__normal__itx, 2191 zilog_t *, zilog, itx_t *, itx); 2192 } 2193 2194 boolean_t synced = txg <= spa_last_synced_txg(spa); 2195 boolean_t frozen = txg > spa_freeze_txg(spa); 2196 2197 /* 2198 * If the txg of this itx has already been synced out, then 2199 * we don't need to commit this itx to an lwb. This is 2200 * because the data of this itx will have already been 2201 * written to the main pool. This is inherently racy, and 2202 * it's still ok to commit an itx whose txg has already 2203 * been synced; this will result in a write that's 2204 * unnecessary, but will do no harm. 2205 * 2206 * With that said, we always want to commit TX_COMMIT itxs 2207 * to an lwb, regardless of whether or not that itx's txg 2208 * has been synced out. We do this to ensure any OPENED lwb 2209 * will always have at least one zil_commit_waiter_t linked 2210 * to the lwb. 2211 * 2212 * As a counter-example, if we skipped TX_COMMIT itx's 2213 * whose txg had already been synced, the following 2214 * situation could occur if we happened to be racing with 2215 * spa_sync: 2216 * 2217 * 1. we commit a non-TX_COMMIT itx to an lwb, where the 2218 * itx's txg is 10 and the last synced txg is 9. 2219 * 2. spa_sync finishes syncing out txg 10. 2220 * 3. we move to the next itx in the list, it's a TX_COMMIT 2221 * whose txg is 10, so we skip it rather than committing 2222 * it to the lwb used in (1). 2223 * 2224 * If the itx that is skipped in (3) is the last TX_COMMIT 2225 * itx in the commit list, than it's possible for the lwb 2226 * used in (1) to remain in the OPENED state indefinitely. 2227 * 2228 * To prevent the above scenario from occuring, ensuring 2229 * that once an lwb is OPENED it will transition to ISSUED 2230 * and eventually DONE, we always commit TX_COMMIT itx's to 2231 * an lwb here, even if that itx's txg has already been 2232 * synced. 2233 * 2234 * Finally, if the pool is frozen, we _always_ commit the 2235 * itx. The point of freezing the pool is to prevent data 2236 * from being written to the main pool via spa_sync, and 2237 * instead rely solely on the ZIL to persistently store the 2238 * data; i.e. when the pool is frozen, the last synced txg 2239 * value can't be trusted. 2240 */ 2241 if (frozen || !synced || lrc->lrc_txtype == TX_COMMIT) { 2242 if (lwb != NULL) { 2243 lwb = zil_lwb_commit(zilog, itx, lwb); 2244 } else if (lrc->lrc_txtype == TX_COMMIT) { 2245 ASSERT3P(lwb, ==, NULL); 2246 zil_commit_waiter_link_nolwb( 2247 itx->itx_private, &nolwb_waiters); 2248 } 2249 } 2250 2251 list_remove(&zilog->zl_itx_commit_list, itx); 2252 zil_itx_destroy(itx); 2253 } 2254 2255 if (lwb == NULL) { 2256 /* 2257 * This indicates zio_alloc_zil() failed to allocate the 2258 * "next" lwb on-disk. When this happens, we must stall 2259 * the ZIL write pipeline; see the comment within 2260 * zil_commit_writer_stall() for more details. 2261 */ 2262 zil_commit_writer_stall(zilog); 2263 2264 /* 2265 * Additionally, we have to signal and mark the "nolwb" 2266 * waiters as "done" here, since without an lwb, we 2267 * can't do this via zil_lwb_flush_vdevs_done() like 2268 * normal. 2269 */ 2270 zil_commit_waiter_t *zcw; 2271 while (zcw = list_head(&nolwb_waiters)) { 2272 zil_commit_waiter_skip(zcw); 2273 list_remove(&nolwb_waiters, zcw); 2274 } 2275 } else { 2276 ASSERT(list_is_empty(&nolwb_waiters)); 2277 ASSERT3P(lwb, !=, NULL); 2278 ASSERT3S(lwb->lwb_state, !=, LWB_STATE_ISSUED); 2279 ASSERT3S(lwb->lwb_state, !=, LWB_STATE_WRITE_DONE); 2280 ASSERT3S(lwb->lwb_state, !=, LWB_STATE_FLUSH_DONE); 2281 2282 /* 2283 * At this point, the ZIL block pointed at by the "lwb" 2284 * variable is in one of the following states: "closed" 2285 * or "open". 2286 * 2287 * If its "closed", then no itxs have been committed to 2288 * it, so there's no point in issuing its zio (i.e. 2289 * it's "empty"). 2290 * 2291 * If its "open" state, then it contains one or more 2292 * itxs that eventually need to be committed to stable 2293 * storage. In this case we intentionally do not issue 2294 * the lwb's zio to disk yet, and instead rely on one of 2295 * the following two mechanisms for issuing the zio: 2296 * 2297 * 1. Ideally, there will be more ZIL activity occuring 2298 * on the system, such that this function will be 2299 * immediately called again (not necessarily by the same 2300 * thread) and this lwb's zio will be issued via 2301 * zil_lwb_commit(). This way, the lwb is guaranteed to 2302 * be "full" when it is issued to disk, and we'll make 2303 * use of the lwb's size the best we can. 2304 * 2305 * 2. If there isn't sufficient ZIL activity occuring on 2306 * the system, such that this lwb's zio isn't issued via 2307 * zil_lwb_commit(), zil_commit_waiter() will issue the 2308 * lwb's zio. If this occurs, the lwb is not guaranteed 2309 * to be "full" by the time its zio is issued, and means 2310 * the size of the lwb was "too large" given the amount 2311 * of ZIL activity occuring on the system at that time. 2312 * 2313 * We do this for a couple of reasons: 2314 * 2315 * 1. To try and reduce the number of IOPs needed to 2316 * write the same number of itxs. If an lwb has space 2317 * available in it's buffer for more itxs, and more itxs 2318 * will be committed relatively soon (relative to the 2319 * latency of performing a write), then it's beneficial 2320 * to wait for these "next" itxs. This way, more itxs 2321 * can be committed to stable storage with fewer writes. 2322 * 2323 * 2. To try and use the largest lwb block size that the 2324 * incoming rate of itxs can support. Again, this is to 2325 * try and pack as many itxs into as few lwbs as 2326 * possible, without significantly impacting the latency 2327 * of each individual itx. 2328 */ 2329 } 2330} 2331 2332/* 2333 * This function is responsible for ensuring the passed in commit waiter 2334 * (and associated commit itx) is committed to an lwb. If the waiter is 2335 * not already committed to an lwb, all itxs in the zilog's queue of 2336 * itxs will be processed. The assumption is the passed in waiter's 2337 * commit itx will found in the queue just like the other non-commit 2338 * itxs, such that when the entire queue is processed, the waiter will 2339 * have been commited to an lwb. 2340 * 2341 * The lwb associated with the passed in waiter is not guaranteed to 2342 * have been issued by the time this function completes. If the lwb is 2343 * not issued, we rely on future calls to zil_commit_writer() to issue 2344 * the lwb, or the timeout mechanism found in zil_commit_waiter(). 2345 */ 2346static void 2347zil_commit_writer(zilog_t *zilog, zil_commit_waiter_t *zcw) 2348{ 2349 ASSERT(!MUTEX_HELD(&zilog->zl_lock)); 2350 ASSERT(spa_writeable(zilog->zl_spa)); 2351 2352 mutex_enter(&zilog->zl_issuer_lock); 2353 2354 if (zcw->zcw_lwb != NULL || zcw->zcw_done) { 2355 /* 2356 * It's possible that, while we were waiting to acquire 2357 * the "zl_issuer_lock", another thread committed this 2358 * waiter to an lwb. If that occurs, we bail out early, 2359 * without processing any of the zilog's queue of itxs. 2360 * 2361 * On certain workloads and system configurations, the 2362 * "zl_issuer_lock" can become highly contended. In an 2363 * attempt to reduce this contention, we immediately drop 2364 * the lock if the waiter has already been processed. 2365 * 2366 * We've measured this optimization to reduce CPU spent 2367 * contending on this lock by up to 5%, using a system 2368 * with 32 CPUs, low latency storage (~50 usec writes), 2369 * and 1024 threads performing sync writes. 2370 */ 2371 goto out; 2372 } 2373 2374 zil_get_commit_list(zilog); 2375 zil_prune_commit_list(zilog); 2376 zil_process_commit_list(zilog); 2377 2378out: 2379 mutex_exit(&zilog->zl_issuer_lock); 2380} 2381 2382static void 2383zil_commit_waiter_timeout(zilog_t *zilog, zil_commit_waiter_t *zcw) 2384{ 2385 ASSERT(!MUTEX_HELD(&zilog->zl_issuer_lock)); 2386 ASSERT(MUTEX_HELD(&zcw->zcw_lock)); 2387 ASSERT3B(zcw->zcw_done, ==, B_FALSE); 2388 2389 lwb_t *lwb = zcw->zcw_lwb; 2390 ASSERT3P(lwb, !=, NULL); 2391 ASSERT3S(lwb->lwb_state, !=, LWB_STATE_CLOSED); 2392 2393 /* 2394 * If the lwb has already been issued by another thread, we can 2395 * immediately return since there's no work to be done (the 2396 * point of this function is to issue the lwb). Additionally, we 2397 * do this prior to acquiring the zl_issuer_lock, to avoid 2398 * acquiring it when it's not necessary to do so. 2399 */ 2400 if (lwb->lwb_state == LWB_STATE_ISSUED || 2401 lwb->lwb_state == LWB_STATE_WRITE_DONE || 2402 lwb->lwb_state == LWB_STATE_FLUSH_DONE) 2403 return; 2404 2405 /* 2406 * In order to call zil_lwb_write_issue() we must hold the 2407 * zilog's "zl_issuer_lock". We can't simply acquire that lock, 2408 * since we're already holding the commit waiter's "zcw_lock", 2409 * and those two locks are aquired in the opposite order 2410 * elsewhere. 2411 */ 2412 mutex_exit(&zcw->zcw_lock); 2413 mutex_enter(&zilog->zl_issuer_lock); 2414 mutex_enter(&zcw->zcw_lock); 2415 2416 /* 2417 * Since we just dropped and re-acquired the commit waiter's 2418 * lock, we have to re-check to see if the waiter was marked 2419 * "done" during that process. If the waiter was marked "done", 2420 * the "lwb" pointer is no longer valid (it can be free'd after 2421 * the waiter is marked "done"), so without this check we could 2422 * wind up with a use-after-free error below. 2423 */ 2424 if (zcw->zcw_done) 2425 goto out; 2426 2427 ASSERT3P(lwb, ==, zcw->zcw_lwb); 2428 2429 /* 2430 * We've already checked this above, but since we hadn't acquired 2431 * the zilog's zl_issuer_lock, we have to perform this check a 2432 * second time while holding the lock. 2433 * 2434 * We don't need to hold the zl_lock since the lwb cannot transition 2435 * from OPENED to ISSUED while we hold the zl_issuer_lock. The lwb 2436 * _can_ transition from ISSUED to DONE, but it's OK to race with 2437 * that transition since we treat the lwb the same, whether it's in 2438 * the ISSUED or DONE states. 2439 * 2440 * The important thing, is we treat the lwb differently depending on 2441 * if it's ISSUED or OPENED, and block any other threads that might 2442 * attempt to issue this lwb. For that reason we hold the 2443 * zl_issuer_lock when checking the lwb_state; we must not call 2444 * zil_lwb_write_issue() if the lwb had already been issued. 2445 * 2446 * See the comment above the lwb_state_t structure definition for 2447 * more details on the lwb states, and locking requirements. 2448 */ 2449 if (lwb->lwb_state == LWB_STATE_ISSUED || 2450 lwb->lwb_state == LWB_STATE_WRITE_DONE || 2451 lwb->lwb_state == LWB_STATE_FLUSH_DONE) 2452 goto out; 2453 2454 ASSERT3S(lwb->lwb_state, ==, LWB_STATE_OPENED); 2455 2456 /* 2457 * As described in the comments above zil_commit_waiter() and 2458 * zil_process_commit_list(), we need to issue this lwb's zio 2459 * since we've reached the commit waiter's timeout and it still 2460 * hasn't been issued. 2461 */ 2462 lwb_t *nlwb = zil_lwb_write_issue(zilog, lwb); 2463 2464 IMPLY(nlwb != NULL, lwb->lwb_state != LWB_STATE_OPENED); 2465 2466 /* 2467 * Since the lwb's zio hadn't been issued by the time this thread 2468 * reached its timeout, we reset the zilog's "zl_cur_used" field 2469 * to influence the zil block size selection algorithm. 2470 * 2471 * By having to issue the lwb's zio here, it means the size of the 2472 * lwb was too large, given the incoming throughput of itxs. By 2473 * setting "zl_cur_used" to zero, we communicate this fact to the 2474 * block size selection algorithm, so it can take this informaiton 2475 * into account, and potentially select a smaller size for the 2476 * next lwb block that is allocated. 2477 */ 2478 zilog->zl_cur_used = 0; 2479 2480 if (nlwb == NULL) { 2481 /* 2482 * When zil_lwb_write_issue() returns NULL, this 2483 * indicates zio_alloc_zil() failed to allocate the 2484 * "next" lwb on-disk. When this occurs, the ZIL write 2485 * pipeline must be stalled; see the comment within the 2486 * zil_commit_writer_stall() function for more details. 2487 * 2488 * We must drop the commit waiter's lock prior to 2489 * calling zil_commit_writer_stall() or else we can wind 2490 * up with the following deadlock: 2491 * 2492 * - This thread is waiting for the txg to sync while 2493 * holding the waiter's lock; txg_wait_synced() is 2494 * used within txg_commit_writer_stall(). 2495 * 2496 * - The txg can't sync because it is waiting for this 2497 * lwb's zio callback to call dmu_tx_commit(). 2498 * 2499 * - The lwb's zio callback can't call dmu_tx_commit() 2500 * because it's blocked trying to acquire the waiter's 2501 * lock, which occurs prior to calling dmu_tx_commit() 2502 */ 2503 mutex_exit(&zcw->zcw_lock); 2504 zil_commit_writer_stall(zilog); 2505 mutex_enter(&zcw->zcw_lock); 2506 } 2507 2508out: 2509 mutex_exit(&zilog->zl_issuer_lock); 2510 ASSERT(MUTEX_HELD(&zcw->zcw_lock)); 2511} 2512 2513/* 2514 * This function is responsible for performing the following two tasks: 2515 * 2516 * 1. its primary responsibility is to block until the given "commit 2517 * waiter" is considered "done". 2518 * 2519 * 2. its secondary responsibility is to issue the zio for the lwb that 2520 * the given "commit waiter" is waiting on, if this function has 2521 * waited "long enough" and the lwb is still in the "open" state. 2522 * 2523 * Given a sufficient amount of itxs being generated and written using 2524 * the ZIL, the lwb's zio will be issued via the zil_lwb_commit() 2525 * function. If this does not occur, this secondary responsibility will 2526 * ensure the lwb is issued even if there is not other synchronous 2527 * activity on the system. 2528 * 2529 * For more details, see zil_process_commit_list(); more specifically, 2530 * the comment at the bottom of that function. 2531 */ 2532static void 2533zil_commit_waiter(zilog_t *zilog, zil_commit_waiter_t *zcw) 2534{ 2535 ASSERT(!MUTEX_HELD(&zilog->zl_lock)); 2536 ASSERT(!MUTEX_HELD(&zilog->zl_issuer_lock)); 2537 ASSERT(spa_writeable(zilog->zl_spa)); 2538 2539 mutex_enter(&zcw->zcw_lock); 2540 2541 /* 2542 * The timeout is scaled based on the lwb latency to avoid 2543 * significantly impacting the latency of each individual itx. 2544 * For more details, see the comment at the bottom of the 2545 * zil_process_commit_list() function. 2546 */ 2547 int pct = MAX(zfs_commit_timeout_pct, 1); 2548#if defined(illumos) || !defined(_KERNEL) 2549 hrtime_t sleep = (zilog->zl_last_lwb_latency * pct) / 100; 2550 hrtime_t wakeup = gethrtime() + sleep; 2551#else 2552 sbintime_t sleep = nstosbt((zilog->zl_last_lwb_latency * pct) / 100); 2553 sbintime_t wakeup = getsbinuptime() + sleep; 2554#endif 2555 boolean_t timedout = B_FALSE; 2556 2557 while (!zcw->zcw_done) { 2558 ASSERT(MUTEX_HELD(&zcw->zcw_lock)); 2559 2560 lwb_t *lwb = zcw->zcw_lwb; 2561 2562 /* 2563 * Usually, the waiter will have a non-NULL lwb field here, 2564 * but it's possible for it to be NULL as a result of 2565 * zil_commit() racing with spa_sync(). 2566 * 2567 * When zil_clean() is called, it's possible for the itxg 2568 * list (which may be cleaned via a taskq) to contain 2569 * commit itxs. When this occurs, the commit waiters linked 2570 * off of these commit itxs will not be committed to an 2571 * lwb. Additionally, these commit waiters will not be 2572 * marked done until zil_commit_waiter_skip() is called via 2573 * zil_itxg_clean(). 2574 * 2575 * Thus, it's possible for this commit waiter (i.e. the 2576 * "zcw" variable) to be found in this "in between" state; 2577 * where it's "zcw_lwb" field is NULL, and it hasn't yet 2578 * been skipped, so it's "zcw_done" field is still B_FALSE. 2579 */ 2580 IMPLY(lwb != NULL, lwb->lwb_state != LWB_STATE_CLOSED); 2581 2582 if (lwb != NULL && lwb->lwb_state == LWB_STATE_OPENED) { 2583 ASSERT3B(timedout, ==, B_FALSE); 2584 2585 /* 2586 * If the lwb hasn't been issued yet, then we 2587 * need to wait with a timeout, in case this 2588 * function needs to issue the lwb after the 2589 * timeout is reached; responsibility (2) from 2590 * the comment above this function. 2591 */ 2592#if defined(illumos) || !defined(_KERNEL) 2593 clock_t timeleft = cv_timedwait_hires(&zcw->zcw_cv, 2594 &zcw->zcw_lock, wakeup, USEC2NSEC(1), 2595 CALLOUT_FLAG_ABSOLUTE); 2596 2597 if (timeleft >= 0 || zcw->zcw_done) 2598 continue; 2599#else 2600 int wait_err = cv_timedwait_sbt(&zcw->zcw_cv, 2601 &zcw->zcw_lock, wakeup, SBT_1NS, C_ABSOLUTE); 2602 if (wait_err != EWOULDBLOCK || zcw->zcw_done) 2603 continue; 2604#endif 2605 2606 timedout = B_TRUE; 2607 zil_commit_waiter_timeout(zilog, zcw); 2608 2609 if (!zcw->zcw_done) { 2610 /* 2611 * If the commit waiter has already been 2612 * marked "done", it's possible for the 2613 * waiter's lwb structure to have already 2614 * been freed. Thus, we can only reliably 2615 * make these assertions if the waiter 2616 * isn't done. 2617 */ 2618 ASSERT3P(lwb, ==, zcw->zcw_lwb); 2619 ASSERT3S(lwb->lwb_state, !=, LWB_STATE_OPENED); 2620 } 2621 } else { 2622 /* 2623 * If the lwb isn't open, then it must have already 2624 * been issued. In that case, there's no need to 2625 * use a timeout when waiting for the lwb to 2626 * complete. 2627 * 2628 * Additionally, if the lwb is NULL, the waiter 2629 * will soon be signalled and marked done via 2630 * zil_clean() and zil_itxg_clean(), so no timeout 2631 * is required. 2632 */ 2633 2634 IMPLY(lwb != NULL, 2635 lwb->lwb_state == LWB_STATE_ISSUED || 2636 lwb->lwb_state == LWB_STATE_WRITE_DONE || 2637 lwb->lwb_state == LWB_STATE_FLUSH_DONE); 2638 cv_wait(&zcw->zcw_cv, &zcw->zcw_lock); 2639 } 2640 } 2641 2642 mutex_exit(&zcw->zcw_lock); 2643} 2644 2645static zil_commit_waiter_t * 2646zil_alloc_commit_waiter() 2647{ 2648 zil_commit_waiter_t *zcw = kmem_cache_alloc(zil_zcw_cache, KM_SLEEP); 2649 2650 cv_init(&zcw->zcw_cv, NULL, CV_DEFAULT, NULL); 2651 mutex_init(&zcw->zcw_lock, NULL, MUTEX_DEFAULT, NULL); 2652 list_link_init(&zcw->zcw_node); 2653 zcw->zcw_lwb = NULL; 2654 zcw->zcw_done = B_FALSE; 2655 zcw->zcw_zio_error = 0; 2656 2657 return (zcw); 2658} 2659 2660static void 2661zil_free_commit_waiter(zil_commit_waiter_t *zcw) 2662{ 2663 ASSERT(!list_link_active(&zcw->zcw_node)); 2664 ASSERT3P(zcw->zcw_lwb, ==, NULL); 2665 ASSERT3B(zcw->zcw_done, ==, B_TRUE); 2666 mutex_destroy(&zcw->zcw_lock); 2667 cv_destroy(&zcw->zcw_cv); 2668 kmem_cache_free(zil_zcw_cache, zcw); 2669} 2670 2671/* 2672 * This function is used to create a TX_COMMIT itx and assign it. This 2673 * way, it will be linked into the ZIL's list of synchronous itxs, and 2674 * then later committed to an lwb (or skipped) when 2675 * zil_process_commit_list() is called. 2676 */ 2677static void 2678zil_commit_itx_assign(zilog_t *zilog, zil_commit_waiter_t *zcw) 2679{ 2680 dmu_tx_t *tx = dmu_tx_create(zilog->zl_os); 2681 VERIFY0(dmu_tx_assign(tx, TXG_WAIT)); 2682 2683 itx_t *itx = zil_itx_create(TX_COMMIT, sizeof (lr_t)); 2684 itx->itx_sync = B_TRUE; 2685 itx->itx_private = zcw; 2686 2687 zil_itx_assign(zilog, itx, tx); 2688 2689 dmu_tx_commit(tx); 2690} 2691 2692/* 2693 * Commit ZFS Intent Log transactions (itxs) to stable storage. 2694 * 2695 * When writing ZIL transactions to the on-disk representation of the 2696 * ZIL, the itxs are committed to a Log Write Block (lwb). Multiple 2697 * itxs can be committed to a single lwb. Once a lwb is written and 2698 * committed to stable storage (i.e. the lwb is written, and vdevs have 2699 * been flushed), each itx that was committed to that lwb is also 2700 * considered to be committed to stable storage. 2701 * 2702 * When an itx is committed to an lwb, the log record (lr_t) contained 2703 * by the itx is copied into the lwb's zio buffer, and once this buffer 2704 * is written to disk, it becomes an on-disk ZIL block. 2705 * 2706 * As itxs are generated, they're inserted into the ZIL's queue of 2707 * uncommitted itxs. The semantics of zil_commit() are such that it will 2708 * block until all itxs that were in the queue when it was called, are 2709 * committed to stable storage. 2710 * 2711 * If "foid" is zero, this means all "synchronous" and "asynchronous" 2712 * itxs, for all objects in the dataset, will be committed to stable 2713 * storage prior to zil_commit() returning. If "foid" is non-zero, all 2714 * "synchronous" itxs for all objects, but only "asynchronous" itxs 2715 * that correspond to the foid passed in, will be committed to stable 2716 * storage prior to zil_commit() returning. 2717 * 2718 * Generally speaking, when zil_commit() is called, the consumer doesn't 2719 * actually care about _all_ of the uncommitted itxs. Instead, they're 2720 * simply trying to waiting for a specific itx to be committed to disk, 2721 * but the interface(s) for interacting with the ZIL don't allow such 2722 * fine-grained communication. A better interface would allow a consumer 2723 * to create and assign an itx, and then pass a reference to this itx to 2724 * zil_commit(); such that zil_commit() would return as soon as that 2725 * specific itx was committed to disk (instead of waiting for _all_ 2726 * itxs to be committed). 2727 * 2728 * When a thread calls zil_commit() a special "commit itx" will be 2729 * generated, along with a corresponding "waiter" for this commit itx. 2730 * zil_commit() will wait on this waiter's CV, such that when the waiter 2731 * is marked done, and signalled, zil_commit() will return. 2732 * 2733 * This commit itx is inserted into the queue of uncommitted itxs. This 2734 * provides an easy mechanism for determining which itxs were in the 2735 * queue prior to zil_commit() having been called, and which itxs were 2736 * added after zil_commit() was called. 2737 * 2738 * The commit it is special; it doesn't have any on-disk representation. 2739 * When a commit itx is "committed" to an lwb, the waiter associated 2740 * with it is linked onto the lwb's list of waiters. Then, when that lwb 2741 * completes, each waiter on the lwb's list is marked done and signalled 2742 * -- allowing the thread waiting on the waiter to return from zil_commit(). 2743 * 2744 * It's important to point out a few critical factors that allow us 2745 * to make use of the commit itxs, commit waiters, per-lwb lists of 2746 * commit waiters, and zio completion callbacks like we're doing: 2747 * 2748 * 1. The list of waiters for each lwb is traversed, and each commit 2749 * waiter is marked "done" and signalled, in the zio completion 2750 * callback of the lwb's zio[*]. 2751 * 2752 * * Actually, the waiters are signalled in the zio completion 2753 * callback of the root zio for the DKIOCFLUSHWRITECACHE commands 2754 * that are sent to the vdevs upon completion of the lwb zio. 2755 * 2756 * 2. When the itxs are inserted into the ZIL's queue of uncommitted 2757 * itxs, the order in which they are inserted is preserved[*]; as 2758 * itxs are added to the queue, they are added to the tail of 2759 * in-memory linked lists. 2760 * 2761 * When committing the itxs to lwbs (to be written to disk), they 2762 * are committed in the same order in which the itxs were added to 2763 * the uncommitted queue's linked list(s); i.e. the linked list of 2764 * itxs to commit is traversed from head to tail, and each itx is 2765 * committed to an lwb in that order. 2766 * 2767 * * To clarify: 2768 * 2769 * - the order of "sync" itxs is preserved w.r.t. other 2770 * "sync" itxs, regardless of the corresponding objects. 2771 * - the order of "async" itxs is preserved w.r.t. other 2772 * "async" itxs corresponding to the same object. 2773 * - the order of "async" itxs is *not* preserved w.r.t. other 2774 * "async" itxs corresponding to different objects. 2775 * - the order of "sync" itxs w.r.t. "async" itxs (or vice 2776 * versa) is *not* preserved, even for itxs that correspond 2777 * to the same object. 2778 * 2779 * For more details, see: zil_itx_assign(), zil_async_to_sync(), 2780 * zil_get_commit_list(), and zil_process_commit_list(). 2781 * 2782 * 3. The lwbs represent a linked list of blocks on disk. Thus, any 2783 * lwb cannot be considered committed to stable storage, until its 2784 * "previous" lwb is also committed to stable storage. This fact, 2785 * coupled with the fact described above, means that itxs are 2786 * committed in (roughly) the order in which they were generated. 2787 * This is essential because itxs are dependent on prior itxs. 2788 * Thus, we *must not* deem an itx as being committed to stable 2789 * storage, until *all* prior itxs have also been committed to 2790 * stable storage. 2791 * 2792 * To enforce this ordering of lwb zio's, while still leveraging as 2793 * much of the underlying storage performance as possible, we rely 2794 * on two fundamental concepts: 2795 * 2796 * 1. The creation and issuance of lwb zio's is protected by 2797 * the zilog's "zl_issuer_lock", which ensures only a single 2798 * thread is creating and/or issuing lwb's at a time 2799 * 2. The "previous" lwb is a child of the "current" lwb 2800 * (leveraging the zio parent-child depenency graph) 2801 * 2802 * By relying on this parent-child zio relationship, we can have 2803 * many lwb zio's concurrently issued to the underlying storage, 2804 * but the order in which they complete will be the same order in 2805 * which they were created. 2806 */ 2807void 2808zil_commit(zilog_t *zilog, uint64_t foid) 2809{ 2810 /* 2811 * We should never attempt to call zil_commit on a snapshot for 2812 * a couple of reasons: 2813 * 2814 * 1. A snapshot may never be modified, thus it cannot have any 2815 * in-flight itxs that would have modified the dataset. 2816 * 2817 * 2. By design, when zil_commit() is called, a commit itx will 2818 * be assigned to this zilog; as a result, the zilog will be 2819 * dirtied. We must not dirty the zilog of a snapshot; there's 2820 * checks in the code that enforce this invariant, and will 2821 * cause a panic if it's not upheld. 2822 */ 2823 ASSERT3B(dmu_objset_is_snapshot(zilog->zl_os), ==, B_FALSE); 2824 2825 if (zilog->zl_sync == ZFS_SYNC_DISABLED) 2826 return; 2827 2828 if (!spa_writeable(zilog->zl_spa)) { 2829 /* 2830 * If the SPA is not writable, there should never be any 2831 * pending itxs waiting to be committed to disk. If that 2832 * weren't true, we'd skip writing those itxs out, and 2833 * would break the sematics of zil_commit(); thus, we're 2834 * verifying that truth before we return to the caller. 2835 */ 2836 ASSERT(list_is_empty(&zilog->zl_lwb_list)); 2837 ASSERT3P(zilog->zl_last_lwb_opened, ==, NULL); 2838 for (int i = 0; i < TXG_SIZE; i++) 2839 ASSERT3P(zilog->zl_itxg[i].itxg_itxs, ==, NULL); 2840 return; 2841 } 2842 2843 /* 2844 * If the ZIL is suspended, we don't want to dirty it by calling 2845 * zil_commit_itx_assign() below, nor can we write out 2846 * lwbs like would be done in zil_commit_write(). Thus, we 2847 * simply rely on txg_wait_synced() to maintain the necessary 2848 * semantics, and avoid calling those functions altogether. 2849 */ 2850 if (zilog->zl_suspend > 0) { 2851 txg_wait_synced(zilog->zl_dmu_pool, 0); 2852 return; 2853 } 2854 2855 zil_commit_impl(zilog, foid); 2856} 2857 2858void 2859zil_commit_impl(zilog_t *zilog, uint64_t foid) 2860{ 2861 /* 2862 * Move the "async" itxs for the specified foid to the "sync" 2863 * queues, such that they will be later committed (or skipped) 2864 * to an lwb when zil_process_commit_list() is called. 2865 * 2866 * Since these "async" itxs must be committed prior to this 2867 * call to zil_commit returning, we must perform this operation 2868 * before we call zil_commit_itx_assign(). 2869 */ 2870 zil_async_to_sync(zilog, foid); 2871 2872 /* 2873 * We allocate a new "waiter" structure which will initially be 2874 * linked to the commit itx using the itx's "itx_private" field. 2875 * Since the commit itx doesn't represent any on-disk state, 2876 * when it's committed to an lwb, rather than copying the its 2877 * lr_t into the lwb's buffer, the commit itx's "waiter" will be 2878 * added to the lwb's list of waiters. Then, when the lwb is 2879 * committed to stable storage, each waiter in the lwb's list of 2880 * waiters will be marked "done", and signalled. 2881 * 2882 * We must create the waiter and assign the commit itx prior to 2883 * calling zil_commit_writer(), or else our specific commit itx 2884 * is not guaranteed to be committed to an lwb prior to calling 2885 * zil_commit_waiter(). 2886 */ 2887 zil_commit_waiter_t *zcw = zil_alloc_commit_waiter(); 2888 zil_commit_itx_assign(zilog, zcw); 2889 2890 zil_commit_writer(zilog, zcw); 2891 zil_commit_waiter(zilog, zcw); 2892 2893 if (zcw->zcw_zio_error != 0) { 2894 /* 2895 * If there was an error writing out the ZIL blocks that 2896 * this thread is waiting on, then we fallback to 2897 * relying on spa_sync() to write out the data this 2898 * thread is waiting on. Obviously this has performance 2899 * implications, but the expectation is for this to be 2900 * an exceptional case, and shouldn't occur often. 2901 */ 2902 DTRACE_PROBE2(zil__commit__io__error, 2903 zilog_t *, zilog, zil_commit_waiter_t *, zcw); 2904 txg_wait_synced(zilog->zl_dmu_pool, 0); 2905 } 2906 2907 zil_free_commit_waiter(zcw); 2908} 2909 2910/* 2911 * Called in syncing context to free committed log blocks and update log header. 2912 */ 2913void 2914zil_sync(zilog_t *zilog, dmu_tx_t *tx) 2915{ 2916 zil_header_t *zh = zil_header_in_syncing_context(zilog); 2917 uint64_t txg = dmu_tx_get_txg(tx); 2918 spa_t *spa = zilog->zl_spa; 2919 uint64_t *replayed_seq = &zilog->zl_replayed_seq[txg & TXG_MASK]; 2920 lwb_t *lwb; 2921 2922 /* 2923 * We don't zero out zl_destroy_txg, so make sure we don't try 2924 * to destroy it twice. 2925 */ 2926 if (spa_sync_pass(spa) != 1) 2927 return; 2928 2929 mutex_enter(&zilog->zl_lock); 2930 2931 ASSERT(zilog->zl_stop_sync == 0); 2932 2933 if (*replayed_seq != 0) { 2934 ASSERT(zh->zh_replay_seq < *replayed_seq); 2935 zh->zh_replay_seq = *replayed_seq; 2936 *replayed_seq = 0; 2937 } 2938 2939 if (zilog->zl_destroy_txg == txg) { 2940 blkptr_t blk = zh->zh_log; 2941 2942 ASSERT(list_head(&zilog->zl_lwb_list) == NULL); 2943 2944 bzero(zh, sizeof (zil_header_t)); 2945 bzero(zilog->zl_replayed_seq, sizeof (zilog->zl_replayed_seq)); 2946 2947 if (zilog->zl_keep_first) { 2948 /* 2949 * If this block was part of log chain that couldn't 2950 * be claimed because a device was missing during 2951 * zil_claim(), but that device later returns, 2952 * then this block could erroneously appear valid. 2953 * To guard against this, assign a new GUID to the new 2954 * log chain so it doesn't matter what blk points to. 2955 */ 2956 zil_init_log_chain(zilog, &blk); 2957 zh->zh_log = blk; 2958 } 2959 } 2960 2961 while ((lwb = list_head(&zilog->zl_lwb_list)) != NULL) { 2962 zh->zh_log = lwb->lwb_blk; 2963 if (lwb->lwb_buf != NULL || lwb->lwb_max_txg > txg) 2964 break; 2965 list_remove(&zilog->zl_lwb_list, lwb); 2966 zio_free(spa, txg, &lwb->lwb_blk); 2967 zil_free_lwb(zilog, lwb); 2968 2969 /* 2970 * If we don't have anything left in the lwb list then 2971 * we've had an allocation failure and we need to zero 2972 * out the zil_header blkptr so that we don't end 2973 * up freeing the same block twice. 2974 */ 2975 if (list_head(&zilog->zl_lwb_list) == NULL) 2976 BP_ZERO(&zh->zh_log); 2977 } 2978 mutex_exit(&zilog->zl_lock); 2979} 2980 2981/* ARGSUSED */ 2982static int 2983zil_lwb_cons(void *vbuf, void *unused, int kmflag) 2984{ 2985 lwb_t *lwb = vbuf; 2986 list_create(&lwb->lwb_waiters, sizeof (zil_commit_waiter_t), 2987 offsetof(zil_commit_waiter_t, zcw_node)); 2988 avl_create(&lwb->lwb_vdev_tree, zil_lwb_vdev_compare, 2989 sizeof (zil_vdev_node_t), offsetof(zil_vdev_node_t, zv_node)); 2990 mutex_init(&lwb->lwb_vdev_lock, NULL, MUTEX_DEFAULT, NULL); 2991 return (0); 2992} 2993 2994/* ARGSUSED */ 2995static void 2996zil_lwb_dest(void *vbuf, void *unused) 2997{ 2998 lwb_t *lwb = vbuf; 2999 mutex_destroy(&lwb->lwb_vdev_lock); 3000 avl_destroy(&lwb->lwb_vdev_tree); 3001 list_destroy(&lwb->lwb_waiters); 3002} 3003 3004void 3005zil_init(void) 3006{ 3007 zil_lwb_cache = kmem_cache_create("zil_lwb_cache", 3008 sizeof (lwb_t), 0, zil_lwb_cons, zil_lwb_dest, NULL, NULL, NULL, 0); 3009 3010 zil_zcw_cache = kmem_cache_create("zil_zcw_cache", 3011 sizeof (zil_commit_waiter_t), 0, NULL, NULL, NULL, NULL, NULL, 0); 3012} 3013 3014void 3015zil_fini(void) 3016{ 3017 kmem_cache_destroy(zil_zcw_cache); 3018 kmem_cache_destroy(zil_lwb_cache); 3019} 3020 3021void 3022zil_set_sync(zilog_t *zilog, uint64_t sync) 3023{ 3024 zilog->zl_sync = sync; 3025} 3026 3027void 3028zil_set_logbias(zilog_t *zilog, uint64_t logbias) 3029{ 3030 zilog->zl_logbias = logbias; 3031} 3032 3033zilog_t * 3034zil_alloc(objset_t *os, zil_header_t *zh_phys) 3035{ 3036 zilog_t *zilog; 3037 3038 zilog = kmem_zalloc(sizeof (zilog_t), KM_SLEEP); 3039 3040 zilog->zl_header = zh_phys; 3041 zilog->zl_os = os; 3042 zilog->zl_spa = dmu_objset_spa(os); 3043 zilog->zl_dmu_pool = dmu_objset_pool(os); 3044 zilog->zl_destroy_txg = TXG_INITIAL - 1; 3045 zilog->zl_logbias = dmu_objset_logbias(os); 3046 zilog->zl_sync = dmu_objset_syncprop(os); 3047 zilog->zl_dirty_max_txg = 0; 3048 zilog->zl_last_lwb_opened = NULL; 3049 zilog->zl_last_lwb_latency = 0; 3050 zilog->zl_max_block_size = zil_maxblocksize; 3051 3052 mutex_init(&zilog->zl_lock, NULL, MUTEX_DEFAULT, NULL); 3053 mutex_init(&zilog->zl_issuer_lock, NULL, MUTEX_DEFAULT, NULL); 3054 3055 for (int i = 0; i < TXG_SIZE; i++) { 3056 mutex_init(&zilog->zl_itxg[i].itxg_lock, NULL, 3057 MUTEX_DEFAULT, NULL); 3058 } 3059 3060 list_create(&zilog->zl_lwb_list, sizeof (lwb_t), 3061 offsetof(lwb_t, lwb_node)); 3062 3063 list_create(&zilog->zl_itx_commit_list, sizeof (itx_t), 3064 offsetof(itx_t, itx_node)); 3065 3066 cv_init(&zilog->zl_cv_suspend, NULL, CV_DEFAULT, NULL); 3067 3068 return (zilog); 3069} 3070 3071void 3072zil_free(zilog_t *zilog) 3073{ 3074 zilog->zl_stop_sync = 1; 3075 3076 ASSERT0(zilog->zl_suspend); 3077 ASSERT0(zilog->zl_suspending); 3078 3079 ASSERT(list_is_empty(&zilog->zl_lwb_list)); 3080 list_destroy(&zilog->zl_lwb_list); 3081 3082 ASSERT(list_is_empty(&zilog->zl_itx_commit_list)); 3083 list_destroy(&zilog->zl_itx_commit_list); 3084 3085 for (int i = 0; i < TXG_SIZE; i++) { 3086 /* 3087 * It's possible for an itx to be generated that doesn't dirty 3088 * a txg (e.g. ztest TX_TRUNCATE). So there's no zil_clean() 3089 * callback to remove the entry. We remove those here. 3090 * 3091 * Also free up the ziltest itxs. 3092 */ 3093 if (zilog->zl_itxg[i].itxg_itxs) 3094 zil_itxg_clean(zilog->zl_itxg[i].itxg_itxs); 3095 mutex_destroy(&zilog->zl_itxg[i].itxg_lock); 3096 } 3097 3098 mutex_destroy(&zilog->zl_issuer_lock); 3099 mutex_destroy(&zilog->zl_lock); 3100 3101 cv_destroy(&zilog->zl_cv_suspend); 3102 3103 kmem_free(zilog, sizeof (zilog_t)); 3104} 3105 3106/* 3107 * Open an intent log. 3108 */ 3109zilog_t * 3110zil_open(objset_t *os, zil_get_data_t *get_data) 3111{ 3112 zilog_t *zilog = dmu_objset_zil(os); 3113 3114 ASSERT3P(zilog->zl_get_data, ==, NULL); 3115 ASSERT3P(zilog->zl_last_lwb_opened, ==, NULL); 3116 ASSERT(list_is_empty(&zilog->zl_lwb_list)); 3117 3118 zilog->zl_get_data = get_data; 3119 3120 return (zilog); 3121} 3122 3123/* 3124 * Close an intent log. 3125 */ 3126void 3127zil_close(zilog_t *zilog) 3128{ 3129 lwb_t *lwb; 3130 uint64_t txg; 3131 3132 if (!dmu_objset_is_snapshot(zilog->zl_os)) { 3133 zil_commit(zilog, 0); 3134 } else { 3135 ASSERT3P(list_tail(&zilog->zl_lwb_list), ==, NULL); 3136 ASSERT0(zilog->zl_dirty_max_txg); 3137 ASSERT3B(zilog_is_dirty(zilog), ==, B_FALSE); 3138 } 3139 3140 mutex_enter(&zilog->zl_lock); 3141 lwb = list_tail(&zilog->zl_lwb_list); 3142 if (lwb == NULL) 3143 txg = zilog->zl_dirty_max_txg; 3144 else 3145 txg = MAX(zilog->zl_dirty_max_txg, lwb->lwb_max_txg); 3146 mutex_exit(&zilog->zl_lock); 3147 3148 /* 3149 * We need to use txg_wait_synced() to wait long enough for the 3150 * ZIL to be clean, and to wait for all pending lwbs to be 3151 * written out. 3152 */ 3153 if (txg) 3154 txg_wait_synced(zilog->zl_dmu_pool, txg); 3155 3156 if (zilog_is_dirty(zilog)) 3157 zfs_dbgmsg("zil (%p) is dirty, txg %llu", zilog, txg); 3158 if (txg < spa_freeze_txg(zilog->zl_spa)) 3159 VERIFY(!zilog_is_dirty(zilog)); 3160 3161 zilog->zl_get_data = NULL; 3162 3163 /* 3164 * We should have only one lwb left on the list; remove it now. 3165 */ 3166 mutex_enter(&zilog->zl_lock); 3167 lwb = list_head(&zilog->zl_lwb_list); 3168 if (lwb != NULL) { 3169 ASSERT3P(lwb, ==, list_tail(&zilog->zl_lwb_list)); 3170 ASSERT3S(lwb->lwb_state, !=, LWB_STATE_ISSUED); 3171 list_remove(&zilog->zl_lwb_list, lwb); 3172 zio_buf_free(lwb->lwb_buf, lwb->lwb_sz); 3173 zil_free_lwb(zilog, lwb); 3174 } 3175 mutex_exit(&zilog->zl_lock); 3176} 3177 3178static char *suspend_tag = "zil suspending"; 3179 3180/* 3181 * Suspend an intent log. While in suspended mode, we still honor 3182 * synchronous semantics, but we rely on txg_wait_synced() to do it. 3183 * On old version pools, we suspend the log briefly when taking a 3184 * snapshot so that it will have an empty intent log. 3185 * 3186 * Long holds are not really intended to be used the way we do here -- 3187 * held for such a short time. A concurrent caller of dsl_dataset_long_held() 3188 * could fail. Therefore we take pains to only put a long hold if it is 3189 * actually necessary. Fortunately, it will only be necessary if the 3190 * objset is currently mounted (or the ZVOL equivalent). In that case it 3191 * will already have a long hold, so we are not really making things any worse. 3192 * 3193 * Ideally, we would locate the existing long-holder (i.e. the zfsvfs_t or 3194 * zvol_state_t), and use their mechanism to prevent their hold from being 3195 * dropped (e.g. VFS_HOLD()). However, that would be even more pain for 3196 * very little gain. 3197 * 3198 * if cookiep == NULL, this does both the suspend & resume. 3199 * Otherwise, it returns with the dataset "long held", and the cookie 3200 * should be passed into zil_resume(). 3201 */ 3202int 3203zil_suspend(const char *osname, void **cookiep) 3204{ 3205 objset_t *os; 3206 zilog_t *zilog; 3207 const zil_header_t *zh; 3208 int error; 3209 3210 error = dmu_objset_hold(osname, suspend_tag, &os); 3211 if (error != 0) 3212 return (error); 3213 zilog = dmu_objset_zil(os); 3214 3215 mutex_enter(&zilog->zl_lock); 3216 zh = zilog->zl_header; 3217 3218 if (zh->zh_flags & ZIL_REPLAY_NEEDED) { /* unplayed log */ 3219 mutex_exit(&zilog->zl_lock); 3220 dmu_objset_rele(os, suspend_tag); 3221 return (SET_ERROR(EBUSY)); 3222 } 3223 3224 /* 3225 * Don't put a long hold in the cases where we can avoid it. This 3226 * is when there is no cookie so we are doing a suspend & resume 3227 * (i.e. called from zil_vdev_offline()), and there's nothing to do 3228 * for the suspend because it's already suspended, or there's no ZIL. 3229 */ 3230 if (cookiep == NULL && !zilog->zl_suspending && 3231 (zilog->zl_suspend > 0 || BP_IS_HOLE(&zh->zh_log))) { 3232 mutex_exit(&zilog->zl_lock); 3233 dmu_objset_rele(os, suspend_tag); 3234 return (0); 3235 } 3236 3237 dsl_dataset_long_hold(dmu_objset_ds(os), suspend_tag); 3238 dsl_pool_rele(dmu_objset_pool(os), suspend_tag); 3239 3240 zilog->zl_suspend++; 3241 3242 if (zilog->zl_suspend > 1) { 3243 /* 3244 * Someone else is already suspending it. 3245 * Just wait for them to finish. 3246 */ 3247 3248 while (zilog->zl_suspending) 3249 cv_wait(&zilog->zl_cv_suspend, &zilog->zl_lock); 3250 mutex_exit(&zilog->zl_lock); 3251 3252 if (cookiep == NULL) 3253 zil_resume(os); 3254 else 3255 *cookiep = os; 3256 return (0); 3257 } 3258 3259 /* 3260 * If there is no pointer to an on-disk block, this ZIL must not 3261 * be active (e.g. filesystem not mounted), so there's nothing 3262 * to clean up. 3263 */ 3264 if (BP_IS_HOLE(&zh->zh_log)) { 3265 ASSERT(cookiep != NULL); /* fast path already handled */ 3266 3267 *cookiep = os; 3268 mutex_exit(&zilog->zl_lock); 3269 return (0); 3270 } 3271 3272 zilog->zl_suspending = B_TRUE; 3273 mutex_exit(&zilog->zl_lock); 3274 3275 /* 3276 * We need to use zil_commit_impl to ensure we wait for all 3277 * LWB_STATE_OPENED and LWB_STATE_ISSUED lwb's to be committed 3278 * to disk before proceeding. If we used zil_commit instead, it 3279 * would just call txg_wait_synced(), because zl_suspend is set. 3280 * txg_wait_synced() doesn't wait for these lwb's to be 3281 * LWB_STATE_FLUSH_DONE before returning. 3282 */ 3283 zil_commit_impl(zilog, 0); 3284 3285 /* 3286 * Now that we've ensured all lwb's are LWB_STATE_FLUSH_DONE, we 3287 * use txg_wait_synced() to ensure the data from the zilog has 3288 * migrated to the main pool before calling zil_destroy(). 3289 */ 3290 txg_wait_synced(zilog->zl_dmu_pool, 0); 3291 3292 zil_destroy(zilog, B_FALSE); 3293 3294 mutex_enter(&zilog->zl_lock); 3295 zilog->zl_suspending = B_FALSE; 3296 cv_broadcast(&zilog->zl_cv_suspend); 3297 mutex_exit(&zilog->zl_lock); 3298 3299 if (cookiep == NULL) 3300 zil_resume(os); 3301 else 3302 *cookiep = os; 3303 return (0); 3304} 3305 3306void 3307zil_resume(void *cookie) 3308{ 3309 objset_t *os = cookie; 3310 zilog_t *zilog = dmu_objset_zil(os); 3311 3312 mutex_enter(&zilog->zl_lock); 3313 ASSERT(zilog->zl_suspend != 0); 3314 zilog->zl_suspend--; 3315 mutex_exit(&zilog->zl_lock); 3316 dsl_dataset_long_rele(dmu_objset_ds(os), suspend_tag); 3317 dsl_dataset_rele(dmu_objset_ds(os), suspend_tag); 3318} 3319 3320typedef struct zil_replay_arg { 3321 zil_replay_func_t **zr_replay; 3322 void *zr_arg; 3323 boolean_t zr_byteswap; 3324 char *zr_lr; 3325} zil_replay_arg_t; 3326 3327static int 3328zil_replay_error(zilog_t *zilog, lr_t *lr, int error) 3329{ 3330 char name[ZFS_MAX_DATASET_NAME_LEN]; 3331 3332 zilog->zl_replaying_seq--; /* didn't actually replay this one */ 3333 3334 dmu_objset_name(zilog->zl_os, name); 3335 3336 cmn_err(CE_WARN, "ZFS replay transaction error %d, " 3337 "dataset %s, seq 0x%llx, txtype %llu %s\n", error, name, 3338 (u_longlong_t)lr->lrc_seq, 3339 (u_longlong_t)(lr->lrc_txtype & ~TX_CI), 3340 (lr->lrc_txtype & TX_CI) ? "CI" : ""); 3341 3342 return (error); 3343} 3344 3345static int 3346zil_replay_log_record(zilog_t *zilog, lr_t *lr, void *zra, uint64_t claim_txg) 3347{ 3348 zil_replay_arg_t *zr = zra; 3349 const zil_header_t *zh = zilog->zl_header; 3350 uint64_t reclen = lr->lrc_reclen; 3351 uint64_t txtype = lr->lrc_txtype; 3352 int error = 0; 3353 3354 zilog->zl_replaying_seq = lr->lrc_seq; 3355 3356 if (lr->lrc_seq <= zh->zh_replay_seq) /* already replayed */ 3357 return (0); 3358 3359 if (lr->lrc_txg < claim_txg) /* already committed */ 3360 return (0); 3361 3362 /* Strip case-insensitive bit, still present in log record */ 3363 txtype &= ~TX_CI; 3364 3365 if (txtype == 0 || txtype >= TX_MAX_TYPE) 3366 return (zil_replay_error(zilog, lr, EINVAL)); 3367 3368 /* 3369 * If this record type can be logged out of order, the object 3370 * (lr_foid) may no longer exist. That's legitimate, not an error. 3371 */ 3372 if (TX_OOO(txtype)) { 3373 error = dmu_object_info(zilog->zl_os, 3374 LR_FOID_GET_OBJ(((lr_ooo_t *)lr)->lr_foid), NULL); 3375 if (error == ENOENT || error == EEXIST) 3376 return (0); 3377 } 3378 3379 /* 3380 * Make a copy of the data so we can revise and extend it. 3381 */ 3382 bcopy(lr, zr->zr_lr, reclen); 3383 3384 /* 3385 * If this is a TX_WRITE with a blkptr, suck in the data. 3386 */ 3387 if (txtype == TX_WRITE && reclen == sizeof (lr_write_t)) { 3388 error = zil_read_log_data(zilog, (lr_write_t *)lr, 3389 zr->zr_lr + reclen); 3390 if (error != 0) 3391 return (zil_replay_error(zilog, lr, error)); 3392 } 3393 3394 /* 3395 * The log block containing this lr may have been byteswapped 3396 * so that we can easily examine common fields like lrc_txtype. 3397 * However, the log is a mix of different record types, and only the 3398 * replay vectors know how to byteswap their records. Therefore, if 3399 * the lr was byteswapped, undo it before invoking the replay vector. 3400 */ 3401 if (zr->zr_byteswap) 3402 byteswap_uint64_array(zr->zr_lr, reclen); 3403 3404 /* 3405 * We must now do two things atomically: replay this log record, 3406 * and update the log header sequence number to reflect the fact that 3407 * we did so. At the end of each replay function the sequence number 3408 * is updated if we are in replay mode. 3409 */ 3410 error = zr->zr_replay[txtype](zr->zr_arg, zr->zr_lr, zr->zr_byteswap); 3411 if (error != 0) { 3412 /* 3413 * The DMU's dnode layer doesn't see removes until the txg 3414 * commits, so a subsequent claim can spuriously fail with 3415 * EEXIST. So if we receive any error we try syncing out 3416 * any removes then retry the transaction. Note that we 3417 * specify B_FALSE for byteswap now, so we don't do it twice. 3418 */ 3419 txg_wait_synced(spa_get_dsl(zilog->zl_spa), 0); 3420 error = zr->zr_replay[txtype](zr->zr_arg, zr->zr_lr, B_FALSE); 3421 if (error != 0) 3422 return (zil_replay_error(zilog, lr, error)); 3423 } 3424 return (0); 3425} 3426 3427/* ARGSUSED */ 3428static int 3429zil_incr_blks(zilog_t *zilog, blkptr_t *bp, void *arg, uint64_t claim_txg) 3430{ 3431 zilog->zl_replay_blks++; 3432 3433 return (0); 3434} 3435 3436/* 3437 * If this dataset has a non-empty intent log, replay it and destroy it. 3438 */ 3439void 3440zil_replay(objset_t *os, void *arg, zil_replay_func_t *replay_func[TX_MAX_TYPE]) 3441{ 3442 zilog_t *zilog = dmu_objset_zil(os); 3443 const zil_header_t *zh = zilog->zl_header; 3444 zil_replay_arg_t zr; 3445 3446 if ((zh->zh_flags & ZIL_REPLAY_NEEDED) == 0) { 3447 zil_destroy(zilog, B_TRUE); 3448 return; 3449 } 3450 3451 zr.zr_replay = replay_func; 3452 zr.zr_arg = arg; 3453 zr.zr_byteswap = BP_SHOULD_BYTESWAP(&zh->zh_log); 3454 zr.zr_lr = kmem_alloc(2 * SPA_MAXBLOCKSIZE, KM_SLEEP); 3455 3456 /* 3457 * Wait for in-progress removes to sync before starting replay. 3458 */ 3459 txg_wait_synced(zilog->zl_dmu_pool, 0); 3460 3461 zilog->zl_replay = B_TRUE; 3462 zilog->zl_replay_time = ddi_get_lbolt(); 3463 ASSERT(zilog->zl_replay_blks == 0); 3464 (void) zil_parse(zilog, zil_incr_blks, zil_replay_log_record, &zr, 3465 zh->zh_claim_txg); 3466 kmem_free(zr.zr_lr, 2 * SPA_MAXBLOCKSIZE); 3467 3468 zil_destroy(zilog, B_FALSE); 3469 txg_wait_synced(zilog->zl_dmu_pool, zilog->zl_destroy_txg); 3470 zilog->zl_replay = B_FALSE; 3471} 3472 3473boolean_t 3474zil_replaying(zilog_t *zilog, dmu_tx_t *tx) 3475{ 3476 if (zilog->zl_sync == ZFS_SYNC_DISABLED) 3477 return (B_TRUE); 3478 3479 if (zilog->zl_replay) { 3480 dsl_dataset_dirty(dmu_objset_ds(zilog->zl_os), tx); 3481 zilog->zl_replayed_seq[dmu_tx_get_txg(tx) & TXG_MASK] = 3482 zilog->zl_replaying_seq; 3483 return (B_TRUE); 3484 } 3485 3486 return (B_FALSE); 3487} 3488 3489/* ARGSUSED */ 3490int 3491zil_reset(const char *osname, void *arg) 3492{ 3493 int error; 3494 3495 error = zil_suspend(osname, NULL); 3496 if (error != 0) 3497 return (SET_ERROR(EEXIST)); 3498 return (0); 3499} 3500