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 * Copyright (c) 2018 Datto Inc. 26 */ 27 28 /* Portions Copyright 2010 Robert Milkowski */ 29 30 #include <sys/zfs_context.h> 31 #include <sys/spa.h> 32 #include <sys/spa_impl.h> 33 #include <sys/dmu.h> 34 #include <sys/zap.h> 35 #include <sys/arc.h> 36 #include <sys/stat.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/metaslab.h> 44 #include <sys/trace_zfs.h> 45 #include <sys/abd.h> 46 47 /* 48 * The ZFS Intent Log (ZIL) saves "transaction records" (itxs) of system 49 * calls that change the file system. Each itx has enough information to 50 * be able to replay them after a system crash, power loss, or 51 * equivalent failure mode. These are stored in memory until either: 52 * 53 * 1. they are committed to the pool by the DMU transaction group 54 * (txg), at which point they can be discarded; or 55 * 2. they are committed to the on-disk ZIL for the dataset being 56 * modified (e.g. due to an fsync, O_DSYNC, or other synchronous 57 * requirement). 58 * 59 * In the event of a crash or power loss, the itxs contained by each 60 * dataset's on-disk ZIL will be replayed when that dataset is first 61 * instantiated (e.g. if the dataset is a normal filesystem, when it is 62 * first mounted). 63 * 64 * As hinted at above, there is one ZIL per dataset (both the in-memory 65 * representation, and the on-disk representation). The on-disk format 66 * consists of 3 parts: 67 * 68 * - a single, per-dataset, ZIL header; which points to a chain of 69 * - zero or more ZIL blocks; each of which contains 70 * - zero or more ZIL records 71 * 72 * A ZIL record holds the information necessary to replay a single 73 * system call transaction. A ZIL block can hold many ZIL records, and 74 * the blocks are chained together, similarly to a singly linked list. 75 * 76 * Each ZIL block contains a block pointer (blkptr_t) to the next ZIL 77 * block in the chain, and the ZIL header points to the first block in 78 * the chain. 79 * 80 * Note, there is not a fixed place in the pool to hold these ZIL 81 * blocks; they are dynamically allocated and freed as needed from the 82 * blocks available on the pool, though they can be preferentially 83 * allocated from a dedicated "log" vdev. 84 */ 85 86 /* 87 * This controls the amount of time that a ZIL block (lwb) will remain 88 * "open" when it isn't "full", and it has a thread waiting for it to be 89 * committed to stable storage. Please refer to the zil_commit_waiter() 90 * function (and the comments within it) for more details. 91 */ 92 static int zfs_commit_timeout_pct = 5; 93 94 /* 95 * See zil.h for more information about these fields. 96 */ 97 static zil_stats_t zil_stats = { 98 { "zil_commit_count", KSTAT_DATA_UINT64 }, 99 { "zil_commit_writer_count", KSTAT_DATA_UINT64 }, 100 { "zil_itx_count", KSTAT_DATA_UINT64 }, 101 { "zil_itx_indirect_count", KSTAT_DATA_UINT64 }, 102 { "zil_itx_indirect_bytes", KSTAT_DATA_UINT64 }, 103 { "zil_itx_copied_count", KSTAT_DATA_UINT64 }, 104 { "zil_itx_copied_bytes", KSTAT_DATA_UINT64 }, 105 { "zil_itx_needcopy_count", KSTAT_DATA_UINT64 }, 106 { "zil_itx_needcopy_bytes", KSTAT_DATA_UINT64 }, 107 { "zil_itx_metaslab_normal_count", KSTAT_DATA_UINT64 }, 108 { "zil_itx_metaslab_normal_bytes", KSTAT_DATA_UINT64 }, 109 { "zil_itx_metaslab_slog_count", KSTAT_DATA_UINT64 }, 110 { "zil_itx_metaslab_slog_bytes", KSTAT_DATA_UINT64 }, 111 }; 112 113 static kstat_t *zil_ksp; 114 115 /* 116 * Disable intent logging replay. This global ZIL switch affects all pools. 117 */ 118 int zil_replay_disable = 0; 119 120 /* 121 * Disable the DKIOCFLUSHWRITECACHE commands that are normally sent to 122 * the disk(s) by the ZIL after an LWB write has completed. Setting this 123 * will cause ZIL corruption on power loss if a volatile out-of-order 124 * write cache is enabled. 125 */ 126 static int zil_nocacheflush = 0; 127 128 /* 129 * Limit SLOG write size per commit executed with synchronous priority. 130 * Any writes above that will be executed with lower (asynchronous) priority 131 * to limit potential SLOG device abuse by single active ZIL writer. 132 */ 133 static unsigned long zil_slog_bulk = 768 * 1024; 134 135 static kmem_cache_t *zil_lwb_cache; 136 static kmem_cache_t *zil_zcw_cache; 137 138 #define LWB_EMPTY(lwb) ((BP_GET_LSIZE(&lwb->lwb_blk) - \ 139 sizeof (zil_chain_t)) == (lwb->lwb_sz - lwb->lwb_nused)) 140 141 static int 142 zil_bp_compare(const void *x1, const void *x2) 143 { 144 const dva_t *dva1 = &((zil_bp_node_t *)x1)->zn_dva; 145 const dva_t *dva2 = &((zil_bp_node_t *)x2)->zn_dva; 146 147 int cmp = TREE_CMP(DVA_GET_VDEV(dva1), DVA_GET_VDEV(dva2)); 148 if (likely(cmp)) 149 return (cmp); 150 151 return (TREE_CMP(DVA_GET_OFFSET(dva1), DVA_GET_OFFSET(dva2))); 152 } 153 154 static void 155 zil_bp_tree_init(zilog_t *zilog) 156 { 157 avl_create(&zilog->zl_bp_tree, zil_bp_compare, 158 sizeof (zil_bp_node_t), offsetof(zil_bp_node_t, zn_node)); 159 } 160 161 static void 162 zil_bp_tree_fini(zilog_t *zilog) 163 { 164 avl_tree_t *t = &zilog->zl_bp_tree; 165 zil_bp_node_t *zn; 166 void *cookie = NULL; 167 168 while ((zn = avl_destroy_nodes(t, &cookie)) != NULL) 169 kmem_free(zn, sizeof (zil_bp_node_t)); 170 171 avl_destroy(t); 172 } 173 174 int 175 zil_bp_tree_add(zilog_t *zilog, const blkptr_t *bp) 176 { 177 avl_tree_t *t = &zilog->zl_bp_tree; 178 const dva_t *dva; 179 zil_bp_node_t *zn; 180 avl_index_t where; 181 182 if (BP_IS_EMBEDDED(bp)) 183 return (0); 184 185 dva = BP_IDENTITY(bp); 186 187 if (avl_find(t, dva, &where) != NULL) 188 return (SET_ERROR(EEXIST)); 189 190 zn = kmem_alloc(sizeof (zil_bp_node_t), KM_SLEEP); 191 zn->zn_dva = *dva; 192 avl_insert(t, zn, where); 193 194 return (0); 195 } 196 197 static zil_header_t * 198 zil_header_in_syncing_context(zilog_t *zilog) 199 { 200 return ((zil_header_t *)zilog->zl_header); 201 } 202 203 static void 204 zil_init_log_chain(zilog_t *zilog, blkptr_t *bp) 205 { 206 zio_cksum_t *zc = &bp->blk_cksum; 207 208 (void) random_get_pseudo_bytes((void *)&zc->zc_word[ZIL_ZC_GUID_0], 209 sizeof (zc->zc_word[ZIL_ZC_GUID_0])); 210 (void) random_get_pseudo_bytes((void *)&zc->zc_word[ZIL_ZC_GUID_1], 211 sizeof (zc->zc_word[ZIL_ZC_GUID_1])); 212 zc->zc_word[ZIL_ZC_OBJSET] = dmu_objset_id(zilog->zl_os); 213 zc->zc_word[ZIL_ZC_SEQ] = 1ULL; 214 } 215 216 /* 217 * Read a log block and make sure it's valid. 218 */ 219 static int 220 zil_read_log_block(zilog_t *zilog, boolean_t decrypt, const blkptr_t *bp, 221 blkptr_t *nbp, void *dst, char **end) 222 { 223 enum zio_flag zio_flags = ZIO_FLAG_CANFAIL; 224 arc_flags_t aflags = ARC_FLAG_WAIT; 225 arc_buf_t *abuf = NULL; 226 zbookmark_phys_t zb; 227 int error; 228 229 if (zilog->zl_header->zh_claim_txg == 0) 230 zio_flags |= ZIO_FLAG_SPECULATIVE | ZIO_FLAG_SCRUB; 231 232 if (!(zilog->zl_header->zh_flags & ZIL_CLAIM_LR_SEQ_VALID)) 233 zio_flags |= ZIO_FLAG_SPECULATIVE; 234 235 if (!decrypt) 236 zio_flags |= ZIO_FLAG_RAW; 237 238 SET_BOOKMARK(&zb, bp->blk_cksum.zc_word[ZIL_ZC_OBJSET], 239 ZB_ZIL_OBJECT, ZB_ZIL_LEVEL, bp->blk_cksum.zc_word[ZIL_ZC_SEQ]); 240 241 error = arc_read(NULL, zilog->zl_spa, bp, arc_getbuf_func, 242 &abuf, ZIO_PRIORITY_SYNC_READ, zio_flags, &aflags, &zb); 243 244 if (error == 0) { 245 zio_cksum_t cksum = bp->blk_cksum; 246 247 /* 248 * Validate the checksummed log block. 249 * 250 * Sequence numbers should be... sequential. The checksum 251 * verifier for the next block should be bp's checksum plus 1. 252 * 253 * Also check the log chain linkage and size used. 254 */ 255 cksum.zc_word[ZIL_ZC_SEQ]++; 256 257 if (BP_GET_CHECKSUM(bp) == ZIO_CHECKSUM_ZILOG2) { 258 zil_chain_t *zilc = abuf->b_data; 259 char *lr = (char *)(zilc + 1); 260 uint64_t len = zilc->zc_nused - sizeof (zil_chain_t); 261 262 if (bcmp(&cksum, &zilc->zc_next_blk.blk_cksum, 263 sizeof (cksum)) || BP_IS_HOLE(&zilc->zc_next_blk)) { 264 error = SET_ERROR(ECKSUM); 265 } else { 266 ASSERT3U(len, <=, SPA_OLD_MAXBLOCKSIZE); 267 bcopy(lr, dst, len); 268 *end = (char *)dst + len; 269 *nbp = zilc->zc_next_blk; 270 } 271 } else { 272 char *lr = abuf->b_data; 273 uint64_t size = BP_GET_LSIZE(bp); 274 zil_chain_t *zilc = (zil_chain_t *)(lr + size) - 1; 275 276 if (bcmp(&cksum, &zilc->zc_next_blk.blk_cksum, 277 sizeof (cksum)) || BP_IS_HOLE(&zilc->zc_next_blk) || 278 (zilc->zc_nused > (size - sizeof (*zilc)))) { 279 error = SET_ERROR(ECKSUM); 280 } else { 281 ASSERT3U(zilc->zc_nused, <=, 282 SPA_OLD_MAXBLOCKSIZE); 283 bcopy(lr, dst, zilc->zc_nused); 284 *end = (char *)dst + zilc->zc_nused; 285 *nbp = zilc->zc_next_blk; 286 } 287 } 288 289 arc_buf_destroy(abuf, &abuf); 290 } 291 292 return (error); 293 } 294 295 /* 296 * Read a TX_WRITE log data block. 297 */ 298 static int 299 zil_read_log_data(zilog_t *zilog, const lr_write_t *lr, void *wbuf) 300 { 301 enum zio_flag zio_flags = ZIO_FLAG_CANFAIL; 302 const blkptr_t *bp = &lr->lr_blkptr; 303 arc_flags_t aflags = ARC_FLAG_WAIT; 304 arc_buf_t *abuf = NULL; 305 zbookmark_phys_t zb; 306 int error; 307 308 if (BP_IS_HOLE(bp)) { 309 if (wbuf != NULL) 310 bzero(wbuf, MAX(BP_GET_LSIZE(bp), lr->lr_length)); 311 return (0); 312 } 313 314 if (zilog->zl_header->zh_claim_txg == 0) 315 zio_flags |= ZIO_FLAG_SPECULATIVE | ZIO_FLAG_SCRUB; 316 317 /* 318 * If we are not using the resulting data, we are just checking that 319 * it hasn't been corrupted so we don't need to waste CPU time 320 * decompressing and decrypting it. 321 */ 322 if (wbuf == NULL) 323 zio_flags |= ZIO_FLAG_RAW; 324 325 SET_BOOKMARK(&zb, dmu_objset_id(zilog->zl_os), lr->lr_foid, 326 ZB_ZIL_LEVEL, lr->lr_offset / BP_GET_LSIZE(bp)); 327 328 error = arc_read(NULL, zilog->zl_spa, bp, arc_getbuf_func, &abuf, 329 ZIO_PRIORITY_SYNC_READ, zio_flags, &aflags, &zb); 330 331 if (error == 0) { 332 if (wbuf != NULL) 333 bcopy(abuf->b_data, wbuf, arc_buf_size(abuf)); 334 arc_buf_destroy(abuf, &abuf); 335 } 336 337 return (error); 338 } 339 340 /* 341 * Parse the intent log, and call parse_func for each valid record within. 342 */ 343 int 344 zil_parse(zilog_t *zilog, zil_parse_blk_func_t *parse_blk_func, 345 zil_parse_lr_func_t *parse_lr_func, void *arg, uint64_t txg, 346 boolean_t decrypt) 347 { 348 const zil_header_t *zh = zilog->zl_header; 349 boolean_t claimed = !!zh->zh_claim_txg; 350 uint64_t claim_blk_seq = claimed ? zh->zh_claim_blk_seq : UINT64_MAX; 351 uint64_t claim_lr_seq = claimed ? zh->zh_claim_lr_seq : UINT64_MAX; 352 uint64_t max_blk_seq = 0; 353 uint64_t max_lr_seq = 0; 354 uint64_t blk_count = 0; 355 uint64_t lr_count = 0; 356 blkptr_t blk, next_blk; 357 char *lrbuf, *lrp; 358 int error = 0; 359 360 bzero(&next_blk, sizeof (blkptr_t)); 361 362 /* 363 * Old logs didn't record the maximum zh_claim_lr_seq. 364 */ 365 if (!(zh->zh_flags & ZIL_CLAIM_LR_SEQ_VALID)) 366 claim_lr_seq = UINT64_MAX; 367 368 /* 369 * Starting at the block pointed to by zh_log we read the log chain. 370 * For each block in the chain we strongly check that block to 371 * ensure its validity. We stop when an invalid block is found. 372 * For each block pointer in the chain we call parse_blk_func(). 373 * For each record in each valid block we call parse_lr_func(). 374 * If the log has been claimed, stop if we encounter a sequence 375 * number greater than the highest claimed sequence number. 376 */ 377 lrbuf = zio_buf_alloc(SPA_OLD_MAXBLOCKSIZE); 378 zil_bp_tree_init(zilog); 379 380 for (blk = zh->zh_log; !BP_IS_HOLE(&blk); blk = next_blk) { 381 uint64_t blk_seq = blk.blk_cksum.zc_word[ZIL_ZC_SEQ]; 382 int reclen; 383 char *end = NULL; 384 385 if (blk_seq > claim_blk_seq) 386 break; 387 388 error = parse_blk_func(zilog, &blk, arg, txg); 389 if (error != 0) 390 break; 391 ASSERT3U(max_blk_seq, <, blk_seq); 392 max_blk_seq = blk_seq; 393 blk_count++; 394 395 if (max_lr_seq == claim_lr_seq && max_blk_seq == claim_blk_seq) 396 break; 397 398 error = zil_read_log_block(zilog, decrypt, &blk, &next_blk, 399 lrbuf, &end); 400 if (error != 0) 401 break; 402 403 for (lrp = lrbuf; lrp < end; lrp += reclen) { 404 lr_t *lr = (lr_t *)lrp; 405 reclen = lr->lrc_reclen; 406 ASSERT3U(reclen, >=, sizeof (lr_t)); 407 if (lr->lrc_seq > claim_lr_seq) 408 goto done; 409 410 error = parse_lr_func(zilog, lr, arg, txg); 411 if (error != 0) 412 goto done; 413 ASSERT3U(max_lr_seq, <, lr->lrc_seq); 414 max_lr_seq = lr->lrc_seq; 415 lr_count++; 416 } 417 } 418 done: 419 zilog->zl_parse_error = error; 420 zilog->zl_parse_blk_seq = max_blk_seq; 421 zilog->zl_parse_lr_seq = max_lr_seq; 422 zilog->zl_parse_blk_count = blk_count; 423 zilog->zl_parse_lr_count = lr_count; 424 425 ASSERT(!claimed || !(zh->zh_flags & ZIL_CLAIM_LR_SEQ_VALID) || 426 (max_blk_seq == claim_blk_seq && max_lr_seq == claim_lr_seq) || 427 (decrypt && error == EIO)); 428 429 zil_bp_tree_fini(zilog); 430 zio_buf_free(lrbuf, SPA_OLD_MAXBLOCKSIZE); 431 432 return (error); 433 } 434 435 static int 436 zil_clear_log_block(zilog_t *zilog, const blkptr_t *bp, void *tx, 437 uint64_t first_txg) 438 { 439 (void) tx; 440 ASSERT(!BP_IS_HOLE(bp)); 441 442 /* 443 * As we call this function from the context of a rewind to a 444 * checkpoint, each ZIL block whose txg is later than the txg 445 * that we rewind to is invalid. Thus, we return -1 so 446 * zil_parse() doesn't attempt to read it. 447 */ 448 if (bp->blk_birth >= first_txg) 449 return (-1); 450 451 if (zil_bp_tree_add(zilog, bp) != 0) 452 return (0); 453 454 zio_free(zilog->zl_spa, first_txg, bp); 455 return (0); 456 } 457 458 static int 459 zil_noop_log_record(zilog_t *zilog, const lr_t *lrc, void *tx, 460 uint64_t first_txg) 461 { 462 (void) zilog, (void) lrc, (void) tx, (void) first_txg; 463 return (0); 464 } 465 466 static int 467 zil_claim_log_block(zilog_t *zilog, const blkptr_t *bp, void *tx, 468 uint64_t first_txg) 469 { 470 /* 471 * Claim log block if not already committed and not already claimed. 472 * If tx == NULL, just verify that the block is claimable. 473 */ 474 if (BP_IS_HOLE(bp) || bp->blk_birth < first_txg || 475 zil_bp_tree_add(zilog, bp) != 0) 476 return (0); 477 478 return (zio_wait(zio_claim(NULL, zilog->zl_spa, 479 tx == NULL ? 0 : first_txg, bp, spa_claim_notify, NULL, 480 ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE | ZIO_FLAG_SCRUB))); 481 } 482 483 static int 484 zil_claim_log_record(zilog_t *zilog, const lr_t *lrc, void *tx, 485 uint64_t first_txg) 486 { 487 lr_write_t *lr = (lr_write_t *)lrc; 488 int error; 489 490 if (lrc->lrc_txtype != TX_WRITE) 491 return (0); 492 493 /* 494 * If the block is not readable, don't claim it. This can happen 495 * in normal operation when a log block is written to disk before 496 * some of the dmu_sync() blocks it points to. In this case, the 497 * transaction cannot have been committed to anyone (we would have 498 * waited for all writes to be stable first), so it is semantically 499 * correct to declare this the end of the log. 500 */ 501 if (lr->lr_blkptr.blk_birth >= first_txg) { 502 error = zil_read_log_data(zilog, lr, NULL); 503 if (error != 0) 504 return (error); 505 } 506 507 return (zil_claim_log_block(zilog, &lr->lr_blkptr, tx, first_txg)); 508 } 509 510 static int 511 zil_free_log_block(zilog_t *zilog, const blkptr_t *bp, void *tx, 512 uint64_t claim_txg) 513 { 514 (void) claim_txg; 515 516 zio_free(zilog->zl_spa, dmu_tx_get_txg(tx), bp); 517 518 return (0); 519 } 520 521 static int 522 zil_free_log_record(zilog_t *zilog, const lr_t *lrc, void *tx, 523 uint64_t claim_txg) 524 { 525 lr_write_t *lr = (lr_write_t *)lrc; 526 blkptr_t *bp = &lr->lr_blkptr; 527 528 /* 529 * If we previously claimed it, we need to free it. 530 */ 531 if (claim_txg != 0 && lrc->lrc_txtype == TX_WRITE && 532 bp->blk_birth >= claim_txg && zil_bp_tree_add(zilog, bp) == 0 && 533 !BP_IS_HOLE(bp)) 534 zio_free(zilog->zl_spa, dmu_tx_get_txg(tx), bp); 535 536 return (0); 537 } 538 539 static int 540 zil_lwb_vdev_compare(const void *x1, const void *x2) 541 { 542 const uint64_t v1 = ((zil_vdev_node_t *)x1)->zv_vdev; 543 const uint64_t v2 = ((zil_vdev_node_t *)x2)->zv_vdev; 544 545 return (TREE_CMP(v1, v2)); 546 } 547 548 static lwb_t * 549 zil_alloc_lwb(zilog_t *zilog, blkptr_t *bp, boolean_t slog, uint64_t txg, 550 boolean_t fastwrite) 551 { 552 lwb_t *lwb; 553 554 lwb = kmem_cache_alloc(zil_lwb_cache, KM_SLEEP); 555 lwb->lwb_zilog = zilog; 556 lwb->lwb_blk = *bp; 557 lwb->lwb_fastwrite = fastwrite; 558 lwb->lwb_slog = slog; 559 lwb->lwb_state = LWB_STATE_CLOSED; 560 lwb->lwb_buf = zio_buf_alloc(BP_GET_LSIZE(bp)); 561 lwb->lwb_max_txg = txg; 562 lwb->lwb_write_zio = NULL; 563 lwb->lwb_root_zio = NULL; 564 lwb->lwb_tx = NULL; 565 lwb->lwb_issued_timestamp = 0; 566 if (BP_GET_CHECKSUM(bp) == ZIO_CHECKSUM_ZILOG2) { 567 lwb->lwb_nused = sizeof (zil_chain_t); 568 lwb->lwb_sz = BP_GET_LSIZE(bp); 569 } else { 570 lwb->lwb_nused = 0; 571 lwb->lwb_sz = BP_GET_LSIZE(bp) - sizeof (zil_chain_t); 572 } 573 574 mutex_enter(&zilog->zl_lock); 575 list_insert_tail(&zilog->zl_lwb_list, lwb); 576 mutex_exit(&zilog->zl_lock); 577 578 ASSERT(!MUTEX_HELD(&lwb->lwb_vdev_lock)); 579 ASSERT(avl_is_empty(&lwb->lwb_vdev_tree)); 580 VERIFY(list_is_empty(&lwb->lwb_waiters)); 581 VERIFY(list_is_empty(&lwb->lwb_itxs)); 582 583 return (lwb); 584 } 585 586 static void 587 zil_free_lwb(zilog_t *zilog, lwb_t *lwb) 588 { 589 ASSERT(MUTEX_HELD(&zilog->zl_lock)); 590 ASSERT(!MUTEX_HELD(&lwb->lwb_vdev_lock)); 591 VERIFY(list_is_empty(&lwb->lwb_waiters)); 592 VERIFY(list_is_empty(&lwb->lwb_itxs)); 593 ASSERT(avl_is_empty(&lwb->lwb_vdev_tree)); 594 ASSERT3P(lwb->lwb_write_zio, ==, NULL); 595 ASSERT3P(lwb->lwb_root_zio, ==, NULL); 596 ASSERT3U(lwb->lwb_max_txg, <=, spa_syncing_txg(zilog->zl_spa)); 597 ASSERT(lwb->lwb_state == LWB_STATE_CLOSED || 598 lwb->lwb_state == LWB_STATE_FLUSH_DONE); 599 600 /* 601 * Clear the zilog's field to indicate this lwb is no longer 602 * valid, and prevent use-after-free errors. 603 */ 604 if (zilog->zl_last_lwb_opened == lwb) 605 zilog->zl_last_lwb_opened = NULL; 606 607 kmem_cache_free(zil_lwb_cache, lwb); 608 } 609 610 /* 611 * Called when we create in-memory log transactions so that we know 612 * to cleanup the itxs at the end of spa_sync(). 613 */ 614 static void 615 zilog_dirty(zilog_t *zilog, uint64_t txg) 616 { 617 dsl_pool_t *dp = zilog->zl_dmu_pool; 618 dsl_dataset_t *ds = dmu_objset_ds(zilog->zl_os); 619 620 ASSERT(spa_writeable(zilog->zl_spa)); 621 622 if (ds->ds_is_snapshot) 623 panic("dirtying snapshot!"); 624 625 if (txg_list_add(&dp->dp_dirty_zilogs, zilog, txg)) { 626 /* up the hold count until we can be written out */ 627 dmu_buf_add_ref(ds->ds_dbuf, zilog); 628 629 zilog->zl_dirty_max_txg = MAX(txg, zilog->zl_dirty_max_txg); 630 } 631 } 632 633 /* 634 * Determine if the zil is dirty in the specified txg. Callers wanting to 635 * ensure that the dirty state does not change must hold the itxg_lock for 636 * the specified txg. Holding the lock will ensure that the zil cannot be 637 * dirtied (zil_itx_assign) or cleaned (zil_clean) while we check its current 638 * state. 639 */ 640 static boolean_t __maybe_unused 641 zilog_is_dirty_in_txg(zilog_t *zilog, uint64_t txg) 642 { 643 dsl_pool_t *dp = zilog->zl_dmu_pool; 644 645 if (txg_list_member(&dp->dp_dirty_zilogs, zilog, txg & TXG_MASK)) 646 return (B_TRUE); 647 return (B_FALSE); 648 } 649 650 /* 651 * Determine if the zil is dirty. The zil is considered dirty if it has 652 * any pending itx records that have not been cleaned by zil_clean(). 653 */ 654 static boolean_t 655 zilog_is_dirty(zilog_t *zilog) 656 { 657 dsl_pool_t *dp = zilog->zl_dmu_pool; 658 659 for (int t = 0; t < TXG_SIZE; t++) { 660 if (txg_list_member(&dp->dp_dirty_zilogs, zilog, t)) 661 return (B_TRUE); 662 } 663 return (B_FALSE); 664 } 665 666 /* 667 * Create an on-disk intent log. 668 */ 669 static lwb_t * 670 zil_create(zilog_t *zilog) 671 { 672 const zil_header_t *zh = zilog->zl_header; 673 lwb_t *lwb = NULL; 674 uint64_t txg = 0; 675 dmu_tx_t *tx = NULL; 676 blkptr_t blk; 677 int error = 0; 678 boolean_t fastwrite = FALSE; 679 boolean_t slog = FALSE; 680 681 /* 682 * Wait for any previous destroy to complete. 683 */ 684 txg_wait_synced(zilog->zl_dmu_pool, zilog->zl_destroy_txg); 685 686 ASSERT(zh->zh_claim_txg == 0); 687 ASSERT(zh->zh_replay_seq == 0); 688 689 blk = zh->zh_log; 690 691 /* 692 * Allocate an initial log block if: 693 * - there isn't one already 694 * - the existing block is the wrong endianness 695 */ 696 if (BP_IS_HOLE(&blk) || BP_SHOULD_BYTESWAP(&blk)) { 697 tx = dmu_tx_create(zilog->zl_os); 698 VERIFY0(dmu_tx_assign(tx, TXG_WAIT)); 699 dsl_dataset_dirty(dmu_objset_ds(zilog->zl_os), tx); 700 txg = dmu_tx_get_txg(tx); 701 702 if (!BP_IS_HOLE(&blk)) { 703 zio_free(zilog->zl_spa, txg, &blk); 704 BP_ZERO(&blk); 705 } 706 707 error = zio_alloc_zil(zilog->zl_spa, zilog->zl_os, txg, &blk, 708 ZIL_MIN_BLKSZ, &slog); 709 fastwrite = TRUE; 710 711 if (error == 0) 712 zil_init_log_chain(zilog, &blk); 713 } 714 715 /* 716 * Allocate a log write block (lwb) for the first log block. 717 */ 718 if (error == 0) 719 lwb = zil_alloc_lwb(zilog, &blk, slog, txg, fastwrite); 720 721 /* 722 * If we just allocated the first log block, commit our transaction 723 * and wait for zil_sync() to stuff the block pointer into zh_log. 724 * (zh is part of the MOS, so we cannot modify it in open context.) 725 */ 726 if (tx != NULL) { 727 dmu_tx_commit(tx); 728 txg_wait_synced(zilog->zl_dmu_pool, txg); 729 } 730 731 ASSERT(error != 0 || bcmp(&blk, &zh->zh_log, sizeof (blk)) == 0); 732 IMPLY(error == 0, lwb != NULL); 733 734 return (lwb); 735 } 736 737 /* 738 * In one tx, free all log blocks and clear the log header. If keep_first 739 * is set, then we're replaying a log with no content. We want to keep the 740 * first block, however, so that the first synchronous transaction doesn't 741 * require a txg_wait_synced() in zil_create(). We don't need to 742 * txg_wait_synced() here either when keep_first is set, because both 743 * zil_create() and zil_destroy() will wait for any in-progress destroys 744 * to complete. 745 */ 746 void 747 zil_destroy(zilog_t *zilog, boolean_t keep_first) 748 { 749 const zil_header_t *zh = zilog->zl_header; 750 lwb_t *lwb; 751 dmu_tx_t *tx; 752 uint64_t txg; 753 754 /* 755 * Wait for any previous destroy to complete. 756 */ 757 txg_wait_synced(zilog->zl_dmu_pool, zilog->zl_destroy_txg); 758 759 zilog->zl_old_header = *zh; /* debugging aid */ 760 761 if (BP_IS_HOLE(&zh->zh_log)) 762 return; 763 764 tx = dmu_tx_create(zilog->zl_os); 765 VERIFY0(dmu_tx_assign(tx, TXG_WAIT)); 766 dsl_dataset_dirty(dmu_objset_ds(zilog->zl_os), tx); 767 txg = dmu_tx_get_txg(tx); 768 769 mutex_enter(&zilog->zl_lock); 770 771 ASSERT3U(zilog->zl_destroy_txg, <, txg); 772 zilog->zl_destroy_txg = txg; 773 zilog->zl_keep_first = keep_first; 774 775 if (!list_is_empty(&zilog->zl_lwb_list)) { 776 ASSERT(zh->zh_claim_txg == 0); 777 VERIFY(!keep_first); 778 while ((lwb = list_head(&zilog->zl_lwb_list)) != NULL) { 779 if (lwb->lwb_fastwrite) 780 metaslab_fastwrite_unmark(zilog->zl_spa, 781 &lwb->lwb_blk); 782 783 list_remove(&zilog->zl_lwb_list, lwb); 784 if (lwb->lwb_buf != NULL) 785 zio_buf_free(lwb->lwb_buf, lwb->lwb_sz); 786 zio_free(zilog->zl_spa, txg, &lwb->lwb_blk); 787 zil_free_lwb(zilog, lwb); 788 } 789 } else if (!keep_first) { 790 zil_destroy_sync(zilog, tx); 791 } 792 mutex_exit(&zilog->zl_lock); 793 794 dmu_tx_commit(tx); 795 } 796 797 void 798 zil_destroy_sync(zilog_t *zilog, dmu_tx_t *tx) 799 { 800 ASSERT(list_is_empty(&zilog->zl_lwb_list)); 801 (void) zil_parse(zilog, zil_free_log_block, 802 zil_free_log_record, tx, zilog->zl_header->zh_claim_txg, B_FALSE); 803 } 804 805 int 806 zil_claim(dsl_pool_t *dp, dsl_dataset_t *ds, void *txarg) 807 { 808 dmu_tx_t *tx = txarg; 809 zilog_t *zilog; 810 uint64_t first_txg; 811 zil_header_t *zh; 812 objset_t *os; 813 int error; 814 815 error = dmu_objset_own_obj(dp, ds->ds_object, 816 DMU_OST_ANY, B_FALSE, B_FALSE, FTAG, &os); 817 if (error != 0) { 818 /* 819 * EBUSY indicates that the objset is inconsistent, in which 820 * case it can not have a ZIL. 821 */ 822 if (error != EBUSY) { 823 cmn_err(CE_WARN, "can't open objset for %llu, error %u", 824 (unsigned long long)ds->ds_object, error); 825 } 826 827 return (0); 828 } 829 830 zilog = dmu_objset_zil(os); 831 zh = zil_header_in_syncing_context(zilog); 832 ASSERT3U(tx->tx_txg, ==, spa_first_txg(zilog->zl_spa)); 833 first_txg = spa_min_claim_txg(zilog->zl_spa); 834 835 /* 836 * If the spa_log_state is not set to be cleared, check whether 837 * the current uberblock is a checkpoint one and if the current 838 * header has been claimed before moving on. 839 * 840 * If the current uberblock is a checkpointed uberblock then 841 * one of the following scenarios took place: 842 * 843 * 1] We are currently rewinding to the checkpoint of the pool. 844 * 2] We crashed in the middle of a checkpoint rewind but we 845 * did manage to write the checkpointed uberblock to the 846 * vdev labels, so when we tried to import the pool again 847 * the checkpointed uberblock was selected from the import 848 * procedure. 849 * 850 * In both cases we want to zero out all the ZIL blocks, except 851 * the ones that have been claimed at the time of the checkpoint 852 * (their zh_claim_txg != 0). The reason is that these blocks 853 * may be corrupted since we may have reused their locations on 854 * disk after we took the checkpoint. 855 * 856 * We could try to set spa_log_state to SPA_LOG_CLEAR earlier 857 * when we first figure out whether the current uberblock is 858 * checkpointed or not. Unfortunately, that would discard all 859 * the logs, including the ones that are claimed, and we would 860 * leak space. 861 */ 862 if (spa_get_log_state(zilog->zl_spa) == SPA_LOG_CLEAR || 863 (zilog->zl_spa->spa_uberblock.ub_checkpoint_txg != 0 && 864 zh->zh_claim_txg == 0)) { 865 if (!BP_IS_HOLE(&zh->zh_log)) { 866 (void) zil_parse(zilog, zil_clear_log_block, 867 zil_noop_log_record, tx, first_txg, B_FALSE); 868 } 869 BP_ZERO(&zh->zh_log); 870 if (os->os_encrypted) 871 os->os_next_write_raw[tx->tx_txg & TXG_MASK] = B_TRUE; 872 dsl_dataset_dirty(dmu_objset_ds(os), tx); 873 dmu_objset_disown(os, B_FALSE, FTAG); 874 return (0); 875 } 876 877 /* 878 * If we are not rewinding and opening the pool normally, then 879 * the min_claim_txg should be equal to the first txg of the pool. 880 */ 881 ASSERT3U(first_txg, ==, spa_first_txg(zilog->zl_spa)); 882 883 /* 884 * Claim all log blocks if we haven't already done so, and remember 885 * the highest claimed sequence number. This ensures that if we can 886 * read only part of the log now (e.g. due to a missing device), 887 * but we can read the entire log later, we will not try to replay 888 * or destroy beyond the last block we successfully claimed. 889 */ 890 ASSERT3U(zh->zh_claim_txg, <=, first_txg); 891 if (zh->zh_claim_txg == 0 && !BP_IS_HOLE(&zh->zh_log)) { 892 (void) zil_parse(zilog, zil_claim_log_block, 893 zil_claim_log_record, tx, first_txg, B_FALSE); 894 zh->zh_claim_txg = first_txg; 895 zh->zh_claim_blk_seq = zilog->zl_parse_blk_seq; 896 zh->zh_claim_lr_seq = zilog->zl_parse_lr_seq; 897 if (zilog->zl_parse_lr_count || zilog->zl_parse_blk_count > 1) 898 zh->zh_flags |= ZIL_REPLAY_NEEDED; 899 zh->zh_flags |= ZIL_CLAIM_LR_SEQ_VALID; 900 if (os->os_encrypted) 901 os->os_next_write_raw[tx->tx_txg & TXG_MASK] = B_TRUE; 902 dsl_dataset_dirty(dmu_objset_ds(os), tx); 903 } 904 905 ASSERT3U(first_txg, ==, (spa_last_synced_txg(zilog->zl_spa) + 1)); 906 dmu_objset_disown(os, B_FALSE, FTAG); 907 return (0); 908 } 909 910 /* 911 * Check the log by walking the log chain. 912 * Checksum errors are ok as they indicate the end of the chain. 913 * Any other error (no device or read failure) returns an error. 914 */ 915 int 916 zil_check_log_chain(dsl_pool_t *dp, dsl_dataset_t *ds, void *tx) 917 { 918 (void) dp; 919 zilog_t *zilog; 920 objset_t *os; 921 blkptr_t *bp; 922 int error; 923 924 ASSERT(tx == NULL); 925 926 error = dmu_objset_from_ds(ds, &os); 927 if (error != 0) { 928 cmn_err(CE_WARN, "can't open objset %llu, error %d", 929 (unsigned long long)ds->ds_object, error); 930 return (0); 931 } 932 933 zilog = dmu_objset_zil(os); 934 bp = (blkptr_t *)&zilog->zl_header->zh_log; 935 936 if (!BP_IS_HOLE(bp)) { 937 vdev_t *vd; 938 boolean_t valid = B_TRUE; 939 940 /* 941 * Check the first block and determine if it's on a log device 942 * which may have been removed or faulted prior to loading this 943 * pool. If so, there's no point in checking the rest of the 944 * log as its content should have already been synced to the 945 * pool. 946 */ 947 spa_config_enter(os->os_spa, SCL_STATE, FTAG, RW_READER); 948 vd = vdev_lookup_top(os->os_spa, DVA_GET_VDEV(&bp->blk_dva[0])); 949 if (vd->vdev_islog && vdev_is_dead(vd)) 950 valid = vdev_log_state_valid(vd); 951 spa_config_exit(os->os_spa, SCL_STATE, FTAG); 952 953 if (!valid) 954 return (0); 955 956 /* 957 * Check whether the current uberblock is checkpointed (e.g. 958 * we are rewinding) and whether the current header has been 959 * claimed or not. If it hasn't then skip verifying it. We 960 * do this because its ZIL blocks may be part of the pool's 961 * state before the rewind, which is no longer valid. 962 */ 963 zil_header_t *zh = zil_header_in_syncing_context(zilog); 964 if (zilog->zl_spa->spa_uberblock.ub_checkpoint_txg != 0 && 965 zh->zh_claim_txg == 0) 966 return (0); 967 } 968 969 /* 970 * Because tx == NULL, zil_claim_log_block() will not actually claim 971 * any blocks, but just determine whether it is possible to do so. 972 * In addition to checking the log chain, zil_claim_log_block() 973 * will invoke zio_claim() with a done func of spa_claim_notify(), 974 * which will update spa_max_claim_txg. See spa_load() for details. 975 */ 976 error = zil_parse(zilog, zil_claim_log_block, zil_claim_log_record, tx, 977 zilog->zl_header->zh_claim_txg ? -1ULL : 978 spa_min_claim_txg(os->os_spa), B_FALSE); 979 980 return ((error == ECKSUM || error == ENOENT) ? 0 : error); 981 } 982 983 /* 984 * When an itx is "skipped", this function is used to properly mark the 985 * waiter as "done, and signal any thread(s) waiting on it. An itx can 986 * be skipped (and not committed to an lwb) for a variety of reasons, 987 * one of them being that the itx was committed via spa_sync(), prior to 988 * it being committed to an lwb; this can happen if a thread calling 989 * zil_commit() is racing with spa_sync(). 990 */ 991 static void 992 zil_commit_waiter_skip(zil_commit_waiter_t *zcw) 993 { 994 mutex_enter(&zcw->zcw_lock); 995 ASSERT3B(zcw->zcw_done, ==, B_FALSE); 996 zcw->zcw_done = B_TRUE; 997 cv_broadcast(&zcw->zcw_cv); 998 mutex_exit(&zcw->zcw_lock); 999 } 1000 1001 /* 1002 * This function is used when the given waiter is to be linked into an 1003 * lwb's "lwb_waiter" list; i.e. when the itx is committed to the lwb. 1004 * At this point, the waiter will no longer be referenced by the itx, 1005 * and instead, will be referenced by the lwb. 1006 */ 1007 static void 1008 zil_commit_waiter_link_lwb(zil_commit_waiter_t *zcw, lwb_t *lwb) 1009 { 1010 /* 1011 * The lwb_waiters field of the lwb is protected by the zilog's 1012 * zl_lock, thus it must be held when calling this function. 1013 */ 1014 ASSERT(MUTEX_HELD(&lwb->lwb_zilog->zl_lock)); 1015 1016 mutex_enter(&zcw->zcw_lock); 1017 ASSERT(!list_link_active(&zcw->zcw_node)); 1018 ASSERT3P(zcw->zcw_lwb, ==, NULL); 1019 ASSERT3P(lwb, !=, NULL); 1020 ASSERT(lwb->lwb_state == LWB_STATE_OPENED || 1021 lwb->lwb_state == LWB_STATE_ISSUED || 1022 lwb->lwb_state == LWB_STATE_WRITE_DONE); 1023 1024 list_insert_tail(&lwb->lwb_waiters, zcw); 1025 zcw->zcw_lwb = lwb; 1026 mutex_exit(&zcw->zcw_lock); 1027 } 1028 1029 /* 1030 * This function is used when zio_alloc_zil() fails to allocate a ZIL 1031 * block, and the given waiter must be linked to the "nolwb waiters" 1032 * list inside of zil_process_commit_list(). 1033 */ 1034 static void 1035 zil_commit_waiter_link_nolwb(zil_commit_waiter_t *zcw, list_t *nolwb) 1036 { 1037 mutex_enter(&zcw->zcw_lock); 1038 ASSERT(!list_link_active(&zcw->zcw_node)); 1039 ASSERT3P(zcw->zcw_lwb, ==, NULL); 1040 list_insert_tail(nolwb, zcw); 1041 mutex_exit(&zcw->zcw_lock); 1042 } 1043 1044 void 1045 zil_lwb_add_block(lwb_t *lwb, const blkptr_t *bp) 1046 { 1047 avl_tree_t *t = &lwb->lwb_vdev_tree; 1048 avl_index_t where; 1049 zil_vdev_node_t *zv, zvsearch; 1050 int ndvas = BP_GET_NDVAS(bp); 1051 int i; 1052 1053 if (zil_nocacheflush) 1054 return; 1055 1056 mutex_enter(&lwb->lwb_vdev_lock); 1057 for (i = 0; i < ndvas; i++) { 1058 zvsearch.zv_vdev = DVA_GET_VDEV(&bp->blk_dva[i]); 1059 if (avl_find(t, &zvsearch, &where) == NULL) { 1060 zv = kmem_alloc(sizeof (*zv), KM_SLEEP); 1061 zv->zv_vdev = zvsearch.zv_vdev; 1062 avl_insert(t, zv, where); 1063 } 1064 } 1065 mutex_exit(&lwb->lwb_vdev_lock); 1066 } 1067 1068 static void 1069 zil_lwb_flush_defer(lwb_t *lwb, lwb_t *nlwb) 1070 { 1071 avl_tree_t *src = &lwb->lwb_vdev_tree; 1072 avl_tree_t *dst = &nlwb->lwb_vdev_tree; 1073 void *cookie = NULL; 1074 zil_vdev_node_t *zv; 1075 1076 ASSERT3S(lwb->lwb_state, ==, LWB_STATE_WRITE_DONE); 1077 ASSERT3S(nlwb->lwb_state, !=, LWB_STATE_WRITE_DONE); 1078 ASSERT3S(nlwb->lwb_state, !=, LWB_STATE_FLUSH_DONE); 1079 1080 /* 1081 * While 'lwb' is at a point in its lifetime where lwb_vdev_tree does 1082 * not need the protection of lwb_vdev_lock (it will only be modified 1083 * while holding zilog->zl_lock) as its writes and those of its 1084 * children have all completed. The younger 'nlwb' may be waiting on 1085 * future writes to additional vdevs. 1086 */ 1087 mutex_enter(&nlwb->lwb_vdev_lock); 1088 /* 1089 * Tear down the 'lwb' vdev tree, ensuring that entries which do not 1090 * exist in 'nlwb' are moved to it, freeing any would-be duplicates. 1091 */ 1092 while ((zv = avl_destroy_nodes(src, &cookie)) != NULL) { 1093 avl_index_t where; 1094 1095 if (avl_find(dst, zv, &where) == NULL) { 1096 avl_insert(dst, zv, where); 1097 } else { 1098 kmem_free(zv, sizeof (*zv)); 1099 } 1100 } 1101 mutex_exit(&nlwb->lwb_vdev_lock); 1102 } 1103 1104 void 1105 zil_lwb_add_txg(lwb_t *lwb, uint64_t txg) 1106 { 1107 lwb->lwb_max_txg = MAX(lwb->lwb_max_txg, txg); 1108 } 1109 1110 /* 1111 * This function is a called after all vdevs associated with a given lwb 1112 * write have completed their DKIOCFLUSHWRITECACHE command; or as soon 1113 * as the lwb write completes, if "zil_nocacheflush" is set. Further, 1114 * all "previous" lwb's will have completed before this function is 1115 * called; i.e. this function is called for all previous lwbs before 1116 * it's called for "this" lwb (enforced via zio the dependencies 1117 * configured in zil_lwb_set_zio_dependency()). 1118 * 1119 * The intention is for this function to be called as soon as the 1120 * contents of an lwb are considered "stable" on disk, and will survive 1121 * any sudden loss of power. At this point, any threads waiting for the 1122 * lwb to reach this state are signalled, and the "waiter" structures 1123 * are marked "done". 1124 */ 1125 static void 1126 zil_lwb_flush_vdevs_done(zio_t *zio) 1127 { 1128 lwb_t *lwb = zio->io_private; 1129 zilog_t *zilog = lwb->lwb_zilog; 1130 dmu_tx_t *tx = lwb->lwb_tx; 1131 zil_commit_waiter_t *zcw; 1132 itx_t *itx; 1133 1134 spa_config_exit(zilog->zl_spa, SCL_STATE, lwb); 1135 1136 zio_buf_free(lwb->lwb_buf, lwb->lwb_sz); 1137 1138 mutex_enter(&zilog->zl_lock); 1139 1140 /* 1141 * Ensure the lwb buffer pointer is cleared before releasing the 1142 * txg. If we have had an allocation failure and the txg is 1143 * waiting to sync then we want zil_sync() to remove the lwb so 1144 * that it's not picked up as the next new one in 1145 * zil_process_commit_list(). zil_sync() will only remove the 1146 * lwb if lwb_buf is null. 1147 */ 1148 lwb->lwb_buf = NULL; 1149 lwb->lwb_tx = NULL; 1150 1151 ASSERT3U(lwb->lwb_issued_timestamp, >, 0); 1152 zilog->zl_last_lwb_latency = gethrtime() - lwb->lwb_issued_timestamp; 1153 1154 lwb->lwb_root_zio = NULL; 1155 1156 ASSERT3S(lwb->lwb_state, ==, LWB_STATE_WRITE_DONE); 1157 lwb->lwb_state = LWB_STATE_FLUSH_DONE; 1158 1159 if (zilog->zl_last_lwb_opened == lwb) { 1160 /* 1161 * Remember the highest committed log sequence number 1162 * for ztest. We only update this value when all the log 1163 * writes succeeded, because ztest wants to ASSERT that 1164 * it got the whole log chain. 1165 */ 1166 zilog->zl_commit_lr_seq = zilog->zl_lr_seq; 1167 } 1168 1169 while ((itx = list_head(&lwb->lwb_itxs)) != NULL) { 1170 list_remove(&lwb->lwb_itxs, itx); 1171 zil_itx_destroy(itx); 1172 } 1173 1174 while ((zcw = list_head(&lwb->lwb_waiters)) != NULL) { 1175 mutex_enter(&zcw->zcw_lock); 1176 1177 ASSERT(list_link_active(&zcw->zcw_node)); 1178 list_remove(&lwb->lwb_waiters, zcw); 1179 1180 ASSERT3P(zcw->zcw_lwb, ==, lwb); 1181 zcw->zcw_lwb = NULL; 1182 /* 1183 * We expect any ZIO errors from child ZIOs to have been 1184 * propagated "up" to this specific LWB's root ZIO, in 1185 * order for this error handling to work correctly. This 1186 * includes ZIO errors from either this LWB's write or 1187 * flush, as well as any errors from other dependent LWBs 1188 * (e.g. a root LWB ZIO that might be a child of this LWB). 1189 * 1190 * With that said, it's important to note that LWB flush 1191 * errors are not propagated up to the LWB root ZIO. 1192 * This is incorrect behavior, and results in VDEV flush 1193 * errors not being handled correctly here. See the 1194 * comment above the call to "zio_flush" for details. 1195 */ 1196 1197 zcw->zcw_zio_error = zio->io_error; 1198 1199 ASSERT3B(zcw->zcw_done, ==, B_FALSE); 1200 zcw->zcw_done = B_TRUE; 1201 cv_broadcast(&zcw->zcw_cv); 1202 1203 mutex_exit(&zcw->zcw_lock); 1204 } 1205 1206 mutex_exit(&zilog->zl_lock); 1207 1208 /* 1209 * Now that we've written this log block, we have a stable pointer 1210 * to the next block in the chain, so it's OK to let the txg in 1211 * which we allocated the next block sync. 1212 */ 1213 dmu_tx_commit(tx); 1214 } 1215 1216 /* 1217 * This is called when an lwb's write zio completes. The callback's 1218 * purpose is to issue the DKIOCFLUSHWRITECACHE commands for the vdevs 1219 * in the lwb's lwb_vdev_tree. The tree will contain the vdevs involved 1220 * in writing out this specific lwb's data, and in the case that cache 1221 * flushes have been deferred, vdevs involved in writing the data for 1222 * previous lwbs. The writes corresponding to all the vdevs in the 1223 * lwb_vdev_tree will have completed by the time this is called, due to 1224 * the zio dependencies configured in zil_lwb_set_zio_dependency(), 1225 * which takes deferred flushes into account. The lwb will be "done" 1226 * once zil_lwb_flush_vdevs_done() is called, which occurs in the zio 1227 * completion callback for the lwb's root zio. 1228 */ 1229 static void 1230 zil_lwb_write_done(zio_t *zio) 1231 { 1232 lwb_t *lwb = zio->io_private; 1233 spa_t *spa = zio->io_spa; 1234 zilog_t *zilog = lwb->lwb_zilog; 1235 avl_tree_t *t = &lwb->lwb_vdev_tree; 1236 void *cookie = NULL; 1237 zil_vdev_node_t *zv; 1238 lwb_t *nlwb; 1239 1240 ASSERT3S(spa_config_held(spa, SCL_STATE, RW_READER), !=, 0); 1241 1242 ASSERT(BP_GET_COMPRESS(zio->io_bp) == ZIO_COMPRESS_OFF); 1243 ASSERT(BP_GET_TYPE(zio->io_bp) == DMU_OT_INTENT_LOG); 1244 ASSERT(BP_GET_LEVEL(zio->io_bp) == 0); 1245 ASSERT(BP_GET_BYTEORDER(zio->io_bp) == ZFS_HOST_BYTEORDER); 1246 ASSERT(!BP_IS_GANG(zio->io_bp)); 1247 ASSERT(!BP_IS_HOLE(zio->io_bp)); 1248 ASSERT(BP_GET_FILL(zio->io_bp) == 0); 1249 1250 abd_free(zio->io_abd); 1251 1252 mutex_enter(&zilog->zl_lock); 1253 ASSERT3S(lwb->lwb_state, ==, LWB_STATE_ISSUED); 1254 lwb->lwb_state = LWB_STATE_WRITE_DONE; 1255 lwb->lwb_write_zio = NULL; 1256 lwb->lwb_fastwrite = FALSE; 1257 nlwb = list_next(&zilog->zl_lwb_list, lwb); 1258 mutex_exit(&zilog->zl_lock); 1259 1260 if (avl_numnodes(t) == 0) 1261 return; 1262 1263 /* 1264 * If there was an IO error, we're not going to call zio_flush() 1265 * on these vdevs, so we simply empty the tree and free the 1266 * nodes. We avoid calling zio_flush() since there isn't any 1267 * good reason for doing so, after the lwb block failed to be 1268 * written out. 1269 * 1270 * Additionally, we don't perform any further error handling at 1271 * this point (e.g. setting "zcw_zio_error" appropriately), as 1272 * we expect that to occur in "zil_lwb_flush_vdevs_done" (thus, 1273 * we expect any error seen here, to have been propagated to 1274 * that function). 1275 */ 1276 if (zio->io_error != 0) { 1277 while ((zv = avl_destroy_nodes(t, &cookie)) != NULL) 1278 kmem_free(zv, sizeof (*zv)); 1279 return; 1280 } 1281 1282 /* 1283 * If this lwb does not have any threads waiting for it to 1284 * complete, we want to defer issuing the DKIOCFLUSHWRITECACHE 1285 * command to the vdevs written to by "this" lwb, and instead 1286 * rely on the "next" lwb to handle the DKIOCFLUSHWRITECACHE 1287 * command for those vdevs. Thus, we merge the vdev tree of 1288 * "this" lwb with the vdev tree of the "next" lwb in the list, 1289 * and assume the "next" lwb will handle flushing the vdevs (or 1290 * deferring the flush(s) again). 1291 * 1292 * This is a useful performance optimization, especially for 1293 * workloads with lots of async write activity and few sync 1294 * write and/or fsync activity, as it has the potential to 1295 * coalesce multiple flush commands to a vdev into one. 1296 */ 1297 if (list_head(&lwb->lwb_waiters) == NULL && nlwb != NULL) { 1298 zil_lwb_flush_defer(lwb, nlwb); 1299 ASSERT(avl_is_empty(&lwb->lwb_vdev_tree)); 1300 return; 1301 } 1302 1303 while ((zv = avl_destroy_nodes(t, &cookie)) != NULL) { 1304 vdev_t *vd = vdev_lookup_top(spa, zv->zv_vdev); 1305 if (vd != NULL) { 1306 /* 1307 * The "ZIO_FLAG_DONT_PROPAGATE" is currently 1308 * always used within "zio_flush". This means, 1309 * any errors when flushing the vdev(s), will 1310 * (unfortunately) not be handled correctly, 1311 * since these "zio_flush" errors will not be 1312 * propagated up to "zil_lwb_flush_vdevs_done". 1313 */ 1314 zio_flush(lwb->lwb_root_zio, vd); 1315 } 1316 kmem_free(zv, sizeof (*zv)); 1317 } 1318 } 1319 1320 static void 1321 zil_lwb_set_zio_dependency(zilog_t *zilog, lwb_t *lwb) 1322 { 1323 lwb_t *last_lwb_opened = zilog->zl_last_lwb_opened; 1324 1325 ASSERT(MUTEX_HELD(&zilog->zl_issuer_lock)); 1326 ASSERT(MUTEX_HELD(&zilog->zl_lock)); 1327 1328 /* 1329 * The zilog's "zl_last_lwb_opened" field is used to build the 1330 * lwb/zio dependency chain, which is used to preserve the 1331 * ordering of lwb completions that is required by the semantics 1332 * of the ZIL. Each new lwb zio becomes a parent of the 1333 * "previous" lwb zio, such that the new lwb's zio cannot 1334 * complete until the "previous" lwb's zio completes. 1335 * 1336 * This is required by the semantics of zil_commit(); the commit 1337 * waiters attached to the lwbs will be woken in the lwb zio's 1338 * completion callback, so this zio dependency graph ensures the 1339 * waiters are woken in the correct order (the same order the 1340 * lwbs were created). 1341 */ 1342 if (last_lwb_opened != NULL && 1343 last_lwb_opened->lwb_state != LWB_STATE_FLUSH_DONE) { 1344 ASSERT(last_lwb_opened->lwb_state == LWB_STATE_OPENED || 1345 last_lwb_opened->lwb_state == LWB_STATE_ISSUED || 1346 last_lwb_opened->lwb_state == LWB_STATE_WRITE_DONE); 1347 1348 ASSERT3P(last_lwb_opened->lwb_root_zio, !=, NULL); 1349 zio_add_child(lwb->lwb_root_zio, 1350 last_lwb_opened->lwb_root_zio); 1351 1352 /* 1353 * If the previous lwb's write hasn't already completed, 1354 * we also want to order the completion of the lwb write 1355 * zios (above, we only order the completion of the lwb 1356 * root zios). This is required because of how we can 1357 * defer the DKIOCFLUSHWRITECACHE commands for each lwb. 1358 * 1359 * When the DKIOCFLUSHWRITECACHE commands are deferred, 1360 * the previous lwb will rely on this lwb to flush the 1361 * vdevs written to by that previous lwb. Thus, we need 1362 * to ensure this lwb doesn't issue the flush until 1363 * after the previous lwb's write completes. We ensure 1364 * this ordering by setting the zio parent/child 1365 * relationship here. 1366 * 1367 * Without this relationship on the lwb's write zio, 1368 * it's possible for this lwb's write to complete prior 1369 * to the previous lwb's write completing; and thus, the 1370 * vdevs for the previous lwb would be flushed prior to 1371 * that lwb's data being written to those vdevs (the 1372 * vdevs are flushed in the lwb write zio's completion 1373 * handler, zil_lwb_write_done()). 1374 */ 1375 if (last_lwb_opened->lwb_state != LWB_STATE_WRITE_DONE) { 1376 ASSERT(last_lwb_opened->lwb_state == LWB_STATE_OPENED || 1377 last_lwb_opened->lwb_state == LWB_STATE_ISSUED); 1378 1379 ASSERT3P(last_lwb_opened->lwb_write_zio, !=, NULL); 1380 zio_add_child(lwb->lwb_write_zio, 1381 last_lwb_opened->lwb_write_zio); 1382 } 1383 } 1384 } 1385 1386 1387 /* 1388 * This function's purpose is to "open" an lwb such that it is ready to 1389 * accept new itxs being committed to it. To do this, the lwb's zio 1390 * structures are created, and linked to the lwb. This function is 1391 * idempotent; if the passed in lwb has already been opened, this 1392 * function is essentially a no-op. 1393 */ 1394 static void 1395 zil_lwb_write_open(zilog_t *zilog, lwb_t *lwb) 1396 { 1397 zbookmark_phys_t zb; 1398 zio_priority_t prio; 1399 1400 ASSERT(MUTEX_HELD(&zilog->zl_issuer_lock)); 1401 ASSERT3P(lwb, !=, NULL); 1402 EQUIV(lwb->lwb_root_zio == NULL, lwb->lwb_state == LWB_STATE_CLOSED); 1403 EQUIV(lwb->lwb_root_zio != NULL, lwb->lwb_state == LWB_STATE_OPENED); 1404 1405 SET_BOOKMARK(&zb, lwb->lwb_blk.blk_cksum.zc_word[ZIL_ZC_OBJSET], 1406 ZB_ZIL_OBJECT, ZB_ZIL_LEVEL, 1407 lwb->lwb_blk.blk_cksum.zc_word[ZIL_ZC_SEQ]); 1408 1409 /* Lock so zil_sync() doesn't fastwrite_unmark after zio is created */ 1410 mutex_enter(&zilog->zl_lock); 1411 if (lwb->lwb_root_zio == NULL) { 1412 abd_t *lwb_abd = abd_get_from_buf(lwb->lwb_buf, 1413 BP_GET_LSIZE(&lwb->lwb_blk)); 1414 1415 if (!lwb->lwb_fastwrite) { 1416 metaslab_fastwrite_mark(zilog->zl_spa, &lwb->lwb_blk); 1417 lwb->lwb_fastwrite = 1; 1418 } 1419 1420 if (!lwb->lwb_slog || zilog->zl_cur_used <= zil_slog_bulk) 1421 prio = ZIO_PRIORITY_SYNC_WRITE; 1422 else 1423 prio = ZIO_PRIORITY_ASYNC_WRITE; 1424 1425 lwb->lwb_root_zio = zio_root(zilog->zl_spa, 1426 zil_lwb_flush_vdevs_done, lwb, ZIO_FLAG_CANFAIL); 1427 ASSERT3P(lwb->lwb_root_zio, !=, NULL); 1428 1429 lwb->lwb_write_zio = zio_rewrite(lwb->lwb_root_zio, 1430 zilog->zl_spa, 0, &lwb->lwb_blk, lwb_abd, 1431 BP_GET_LSIZE(&lwb->lwb_blk), zil_lwb_write_done, lwb, 1432 prio, ZIO_FLAG_CANFAIL | ZIO_FLAG_FASTWRITE, &zb); 1433 ASSERT3P(lwb->lwb_write_zio, !=, NULL); 1434 1435 lwb->lwb_state = LWB_STATE_OPENED; 1436 1437 zil_lwb_set_zio_dependency(zilog, lwb); 1438 zilog->zl_last_lwb_opened = lwb; 1439 } 1440 mutex_exit(&zilog->zl_lock); 1441 1442 ASSERT3P(lwb->lwb_root_zio, !=, NULL); 1443 ASSERT3P(lwb->lwb_write_zio, !=, NULL); 1444 ASSERT3S(lwb->lwb_state, ==, LWB_STATE_OPENED); 1445 } 1446 1447 /* 1448 * Define a limited set of intent log block sizes. 1449 * 1450 * These must be a multiple of 4KB. Note only the amount used (again 1451 * aligned to 4KB) actually gets written. However, we can't always just 1452 * allocate SPA_OLD_MAXBLOCKSIZE as the slog space could be exhausted. 1453 */ 1454 static const struct { 1455 uint64_t limit; 1456 uint64_t blksz; 1457 } zil_block_buckets[] = { 1458 { 4096, 4096 }, /* non TX_WRITE */ 1459 { 8192 + 4096, 8192 + 4096 }, /* database */ 1460 { 32768 + 4096, 32768 + 4096 }, /* NFS writes */ 1461 { 65536 + 4096, 65536 + 4096 }, /* 64KB writes */ 1462 { 131072, 131072 }, /* < 128KB writes */ 1463 { 131072 +4096, 65536 + 4096 }, /* 128KB writes */ 1464 { UINT64_MAX, SPA_OLD_MAXBLOCKSIZE}, /* > 128KB writes */ 1465 }; 1466 1467 /* 1468 * Maximum block size used by the ZIL. This is picked up when the ZIL is 1469 * initialized. Otherwise this should not be used directly; see 1470 * zl_max_block_size instead. 1471 */ 1472 static int zil_maxblocksize = SPA_OLD_MAXBLOCKSIZE; 1473 1474 /* 1475 * Start a log block write and advance to the next log block. 1476 * Calls are serialized. 1477 */ 1478 static lwb_t * 1479 zil_lwb_write_issue(zilog_t *zilog, lwb_t *lwb) 1480 { 1481 lwb_t *nlwb = NULL; 1482 zil_chain_t *zilc; 1483 spa_t *spa = zilog->zl_spa; 1484 blkptr_t *bp; 1485 dmu_tx_t *tx; 1486 uint64_t txg; 1487 uint64_t zil_blksz, wsz; 1488 int i, error; 1489 boolean_t slog; 1490 1491 ASSERT(MUTEX_HELD(&zilog->zl_issuer_lock)); 1492 ASSERT3P(lwb->lwb_root_zio, !=, NULL); 1493 ASSERT3P(lwb->lwb_write_zio, !=, NULL); 1494 ASSERT3S(lwb->lwb_state, ==, LWB_STATE_OPENED); 1495 1496 if (BP_GET_CHECKSUM(&lwb->lwb_blk) == ZIO_CHECKSUM_ZILOG2) { 1497 zilc = (zil_chain_t *)lwb->lwb_buf; 1498 bp = &zilc->zc_next_blk; 1499 } else { 1500 zilc = (zil_chain_t *)(lwb->lwb_buf + lwb->lwb_sz); 1501 bp = &zilc->zc_next_blk; 1502 } 1503 1504 ASSERT(lwb->lwb_nused <= lwb->lwb_sz); 1505 1506 /* 1507 * Allocate the next block and save its address in this block 1508 * before writing it in order to establish the log chain. 1509 * Note that if the allocation of nlwb synced before we wrote 1510 * the block that points at it (lwb), we'd leak it if we crashed. 1511 * Therefore, we don't do dmu_tx_commit() until zil_lwb_write_done(). 1512 * We dirty the dataset to ensure that zil_sync() will be called 1513 * to clean up in the event of allocation failure or I/O failure. 1514 */ 1515 1516 tx = dmu_tx_create(zilog->zl_os); 1517 1518 /* 1519 * Since we are not going to create any new dirty data, and we 1520 * can even help with clearing the existing dirty data, we 1521 * should not be subject to the dirty data based delays. We 1522 * use TXG_NOTHROTTLE to bypass the delay mechanism. 1523 */ 1524 VERIFY0(dmu_tx_assign(tx, TXG_WAIT | TXG_NOTHROTTLE)); 1525 1526 dsl_dataset_dirty(dmu_objset_ds(zilog->zl_os), tx); 1527 txg = dmu_tx_get_txg(tx); 1528 1529 lwb->lwb_tx = tx; 1530 1531 /* 1532 * Log blocks are pre-allocated. Here we select the size of the next 1533 * block, based on size used in the last block. 1534 * - first find the smallest bucket that will fit the block from a 1535 * limited set of block sizes. This is because it's faster to write 1536 * blocks allocated from the same metaslab as they are adjacent or 1537 * close. 1538 * - next find the maximum from the new suggested size and an array of 1539 * previous sizes. This lessens a picket fence effect of wrongly 1540 * guessing the size if we have a stream of say 2k, 64k, 2k, 64k 1541 * requests. 1542 * 1543 * Note we only write what is used, but we can't just allocate 1544 * the maximum block size because we can exhaust the available 1545 * pool log space. 1546 */ 1547 zil_blksz = zilog->zl_cur_used + sizeof (zil_chain_t); 1548 for (i = 0; zil_blksz > zil_block_buckets[i].limit; i++) 1549 continue; 1550 zil_blksz = MIN(zil_block_buckets[i].blksz, zilog->zl_max_block_size); 1551 zilog->zl_prev_blks[zilog->zl_prev_rotor] = zil_blksz; 1552 for (i = 0; i < ZIL_PREV_BLKS; i++) 1553 zil_blksz = MAX(zil_blksz, zilog->zl_prev_blks[i]); 1554 zilog->zl_prev_rotor = (zilog->zl_prev_rotor + 1) & (ZIL_PREV_BLKS - 1); 1555 1556 BP_ZERO(bp); 1557 error = zio_alloc_zil(spa, zilog->zl_os, txg, bp, zil_blksz, &slog); 1558 if (slog) { 1559 ZIL_STAT_BUMP(zil_itx_metaslab_slog_count); 1560 ZIL_STAT_INCR(zil_itx_metaslab_slog_bytes, lwb->lwb_nused); 1561 } else { 1562 ZIL_STAT_BUMP(zil_itx_metaslab_normal_count); 1563 ZIL_STAT_INCR(zil_itx_metaslab_normal_bytes, lwb->lwb_nused); 1564 } 1565 if (error == 0) { 1566 ASSERT3U(bp->blk_birth, ==, txg); 1567 bp->blk_cksum = lwb->lwb_blk.blk_cksum; 1568 bp->blk_cksum.zc_word[ZIL_ZC_SEQ]++; 1569 1570 /* 1571 * Allocate a new log write block (lwb). 1572 */ 1573 nlwb = zil_alloc_lwb(zilog, bp, slog, txg, TRUE); 1574 } 1575 1576 if (BP_GET_CHECKSUM(&lwb->lwb_blk) == ZIO_CHECKSUM_ZILOG2) { 1577 /* For Slim ZIL only write what is used. */ 1578 wsz = P2ROUNDUP_TYPED(lwb->lwb_nused, ZIL_MIN_BLKSZ, uint64_t); 1579 ASSERT3U(wsz, <=, lwb->lwb_sz); 1580 zio_shrink(lwb->lwb_write_zio, wsz); 1581 1582 } else { 1583 wsz = lwb->lwb_sz; 1584 } 1585 1586 zilc->zc_pad = 0; 1587 zilc->zc_nused = lwb->lwb_nused; 1588 zilc->zc_eck.zec_cksum = lwb->lwb_blk.blk_cksum; 1589 1590 /* 1591 * clear unused data for security 1592 */ 1593 bzero(lwb->lwb_buf + lwb->lwb_nused, wsz - lwb->lwb_nused); 1594 1595 spa_config_enter(zilog->zl_spa, SCL_STATE, lwb, RW_READER); 1596 1597 zil_lwb_add_block(lwb, &lwb->lwb_blk); 1598 lwb->lwb_issued_timestamp = gethrtime(); 1599 lwb->lwb_state = LWB_STATE_ISSUED; 1600 1601 zio_nowait(lwb->lwb_root_zio); 1602 zio_nowait(lwb->lwb_write_zio); 1603 1604 /* 1605 * If there was an allocation failure then nlwb will be null which 1606 * forces a txg_wait_synced(). 1607 */ 1608 return (nlwb); 1609 } 1610 1611 /* 1612 * Maximum amount of write data that can be put into single log block. 1613 */ 1614 uint64_t 1615 zil_max_log_data(zilog_t *zilog) 1616 { 1617 return (zilog->zl_max_block_size - 1618 sizeof (zil_chain_t) - sizeof (lr_write_t)); 1619 } 1620 1621 /* 1622 * Maximum amount of log space we agree to waste to reduce number of 1623 * WR_NEED_COPY chunks to reduce zl_get_data() overhead (~12%). 1624 */ 1625 static inline uint64_t 1626 zil_max_waste_space(zilog_t *zilog) 1627 { 1628 return (zil_max_log_data(zilog) / 8); 1629 } 1630 1631 /* 1632 * Maximum amount of write data for WR_COPIED. For correctness, consumers 1633 * must fall back to WR_NEED_COPY if we can't fit the entire record into one 1634 * maximum sized log block, because each WR_COPIED record must fit in a 1635 * single log block. For space efficiency, we want to fit two records into a 1636 * max-sized log block. 1637 */ 1638 uint64_t 1639 zil_max_copied_data(zilog_t *zilog) 1640 { 1641 return ((zilog->zl_max_block_size - sizeof (zil_chain_t)) / 2 - 1642 sizeof (lr_write_t)); 1643 } 1644 1645 static lwb_t * 1646 zil_lwb_commit(zilog_t *zilog, itx_t *itx, lwb_t *lwb) 1647 { 1648 lr_t *lrcb, *lrc; 1649 lr_write_t *lrwb, *lrw; 1650 char *lr_buf; 1651 uint64_t dlen, dnow, dpad, lwb_sp, reclen, txg, max_log_data; 1652 1653 ASSERT(MUTEX_HELD(&zilog->zl_issuer_lock)); 1654 ASSERT3P(lwb, !=, NULL); 1655 ASSERT3P(lwb->lwb_buf, !=, NULL); 1656 1657 zil_lwb_write_open(zilog, lwb); 1658 1659 lrc = &itx->itx_lr; 1660 lrw = (lr_write_t *)lrc; 1661 1662 /* 1663 * A commit itx doesn't represent any on-disk state; instead 1664 * it's simply used as a place holder on the commit list, and 1665 * provides a mechanism for attaching a "commit waiter" onto the 1666 * correct lwb (such that the waiter can be signalled upon 1667 * completion of that lwb). Thus, we don't process this itx's 1668 * log record if it's a commit itx (these itx's don't have log 1669 * records), and instead link the itx's waiter onto the lwb's 1670 * list of waiters. 1671 * 1672 * For more details, see the comment above zil_commit(). 1673 */ 1674 if (lrc->lrc_txtype == TX_COMMIT) { 1675 mutex_enter(&zilog->zl_lock); 1676 zil_commit_waiter_link_lwb(itx->itx_private, lwb); 1677 itx->itx_private = NULL; 1678 mutex_exit(&zilog->zl_lock); 1679 return (lwb); 1680 } 1681 1682 if (lrc->lrc_txtype == TX_WRITE && itx->itx_wr_state == WR_NEED_COPY) { 1683 dlen = P2ROUNDUP_TYPED( 1684 lrw->lr_length, sizeof (uint64_t), uint64_t); 1685 dpad = dlen - lrw->lr_length; 1686 } else { 1687 dlen = dpad = 0; 1688 } 1689 reclen = lrc->lrc_reclen; 1690 zilog->zl_cur_used += (reclen + dlen); 1691 txg = lrc->lrc_txg; 1692 1693 ASSERT3U(zilog->zl_cur_used, <, UINT64_MAX - (reclen + dlen)); 1694 1695 cont: 1696 /* 1697 * If this record won't fit in the current log block, start a new one. 1698 * For WR_NEED_COPY optimize layout for minimal number of chunks. 1699 */ 1700 lwb_sp = lwb->lwb_sz - lwb->lwb_nused; 1701 max_log_data = zil_max_log_data(zilog); 1702 if (reclen > lwb_sp || (reclen + dlen > lwb_sp && 1703 lwb_sp < zil_max_waste_space(zilog) && 1704 (dlen % max_log_data == 0 || 1705 lwb_sp < reclen + dlen % max_log_data))) { 1706 lwb = zil_lwb_write_issue(zilog, lwb); 1707 if (lwb == NULL) 1708 return (NULL); 1709 zil_lwb_write_open(zilog, lwb); 1710 ASSERT(LWB_EMPTY(lwb)); 1711 lwb_sp = lwb->lwb_sz - lwb->lwb_nused; 1712 1713 /* 1714 * There must be enough space in the new, empty log block to 1715 * hold reclen. For WR_COPIED, we need to fit the whole 1716 * record in one block, and reclen is the header size + the 1717 * data size. For WR_NEED_COPY, we can create multiple 1718 * records, splitting the data into multiple blocks, so we 1719 * only need to fit one word of data per block; in this case 1720 * reclen is just the header size (no data). 1721 */ 1722 ASSERT3U(reclen + MIN(dlen, sizeof (uint64_t)), <=, lwb_sp); 1723 } 1724 1725 dnow = MIN(dlen, lwb_sp - reclen); 1726 lr_buf = lwb->lwb_buf + lwb->lwb_nused; 1727 bcopy(lrc, lr_buf, reclen); 1728 lrcb = (lr_t *)lr_buf; /* Like lrc, but inside lwb. */ 1729 lrwb = (lr_write_t *)lrcb; /* Like lrw, but inside lwb. */ 1730 1731 ZIL_STAT_BUMP(zil_itx_count); 1732 1733 /* 1734 * If it's a write, fetch the data or get its blkptr as appropriate. 1735 */ 1736 if (lrc->lrc_txtype == TX_WRITE) { 1737 if (txg > spa_freeze_txg(zilog->zl_spa)) 1738 txg_wait_synced(zilog->zl_dmu_pool, txg); 1739 if (itx->itx_wr_state == WR_COPIED) { 1740 ZIL_STAT_BUMP(zil_itx_copied_count); 1741 ZIL_STAT_INCR(zil_itx_copied_bytes, lrw->lr_length); 1742 } else { 1743 char *dbuf; 1744 int error; 1745 1746 if (itx->itx_wr_state == WR_NEED_COPY) { 1747 dbuf = lr_buf + reclen; 1748 lrcb->lrc_reclen += dnow; 1749 if (lrwb->lr_length > dnow) 1750 lrwb->lr_length = dnow; 1751 lrw->lr_offset += dnow; 1752 lrw->lr_length -= dnow; 1753 ZIL_STAT_BUMP(zil_itx_needcopy_count); 1754 ZIL_STAT_INCR(zil_itx_needcopy_bytes, dnow); 1755 } else { 1756 ASSERT3S(itx->itx_wr_state, ==, WR_INDIRECT); 1757 dbuf = NULL; 1758 ZIL_STAT_BUMP(zil_itx_indirect_count); 1759 ZIL_STAT_INCR(zil_itx_indirect_bytes, 1760 lrw->lr_length); 1761 } 1762 1763 /* 1764 * We pass in the "lwb_write_zio" rather than 1765 * "lwb_root_zio" so that the "lwb_write_zio" 1766 * becomes the parent of any zio's created by 1767 * the "zl_get_data" callback. The vdevs are 1768 * flushed after the "lwb_write_zio" completes, 1769 * so we want to make sure that completion 1770 * callback waits for these additional zio's, 1771 * such that the vdevs used by those zio's will 1772 * be included in the lwb's vdev tree, and those 1773 * vdevs will be properly flushed. If we passed 1774 * in "lwb_root_zio" here, then these additional 1775 * vdevs may not be flushed; e.g. if these zio's 1776 * completed after "lwb_write_zio" completed. 1777 */ 1778 error = zilog->zl_get_data(itx->itx_private, 1779 itx->itx_gen, lrwb, dbuf, lwb, 1780 lwb->lwb_write_zio); 1781 if (dbuf != NULL && error == 0 && dnow == dlen) 1782 /* Zero any padding bytes in the last block. */ 1783 bzero((char *)dbuf + lrwb->lr_length, dpad); 1784 1785 if (error == EIO) { 1786 txg_wait_synced(zilog->zl_dmu_pool, txg); 1787 return (lwb); 1788 } 1789 if (error != 0) { 1790 ASSERT(error == ENOENT || error == EEXIST || 1791 error == EALREADY); 1792 return (lwb); 1793 } 1794 } 1795 } 1796 1797 /* 1798 * We're actually making an entry, so update lrc_seq to be the 1799 * log record sequence number. Note that this is generally not 1800 * equal to the itx sequence number because not all transactions 1801 * are synchronous, and sometimes spa_sync() gets there first. 1802 */ 1803 lrcb->lrc_seq = ++zilog->zl_lr_seq; 1804 lwb->lwb_nused += reclen + dnow; 1805 1806 zil_lwb_add_txg(lwb, txg); 1807 1808 ASSERT3U(lwb->lwb_nused, <=, lwb->lwb_sz); 1809 ASSERT0(P2PHASE(lwb->lwb_nused, sizeof (uint64_t))); 1810 1811 dlen -= dnow; 1812 if (dlen > 0) { 1813 zilog->zl_cur_used += reclen; 1814 goto cont; 1815 } 1816 1817 return (lwb); 1818 } 1819 1820 itx_t * 1821 zil_itx_create(uint64_t txtype, size_t olrsize) 1822 { 1823 size_t itxsize, lrsize; 1824 itx_t *itx; 1825 1826 lrsize = P2ROUNDUP_TYPED(olrsize, sizeof (uint64_t), size_t); 1827 itxsize = offsetof(itx_t, itx_lr) + lrsize; 1828 1829 itx = zio_data_buf_alloc(itxsize); 1830 itx->itx_lr.lrc_txtype = txtype; 1831 itx->itx_lr.lrc_reclen = lrsize; 1832 itx->itx_lr.lrc_seq = 0; /* defensive */ 1833 bzero((char *)&itx->itx_lr + olrsize, lrsize - olrsize); 1834 itx->itx_sync = B_TRUE; /* default is synchronous */ 1835 itx->itx_callback = NULL; 1836 itx->itx_callback_data = NULL; 1837 itx->itx_size = itxsize; 1838 1839 return (itx); 1840 } 1841 1842 void 1843 zil_itx_destroy(itx_t *itx) 1844 { 1845 IMPLY(itx->itx_lr.lrc_txtype == TX_COMMIT, itx->itx_callback == NULL); 1846 IMPLY(itx->itx_callback != NULL, itx->itx_lr.lrc_txtype != TX_COMMIT); 1847 1848 if (itx->itx_callback != NULL) 1849 itx->itx_callback(itx->itx_callback_data); 1850 1851 zio_data_buf_free(itx, itx->itx_size); 1852 } 1853 1854 /* 1855 * Free up the sync and async itxs. The itxs_t has already been detached 1856 * so no locks are needed. 1857 */ 1858 static void 1859 zil_itxg_clean(void *arg) 1860 { 1861 itx_t *itx; 1862 list_t *list; 1863 avl_tree_t *t; 1864 void *cookie; 1865 itxs_t *itxs = arg; 1866 itx_async_node_t *ian; 1867 1868 list = &itxs->i_sync_list; 1869 while ((itx = list_head(list)) != NULL) { 1870 /* 1871 * In the general case, commit itxs will not be found 1872 * here, as they'll be committed to an lwb via 1873 * zil_lwb_commit(), and free'd in that function. Having 1874 * said that, it is still possible for commit itxs to be 1875 * found here, due to the following race: 1876 * 1877 * - a thread calls zil_commit() which assigns the 1878 * commit itx to a per-txg i_sync_list 1879 * - zil_itxg_clean() is called (e.g. via spa_sync()) 1880 * while the waiter is still on the i_sync_list 1881 * 1882 * There's nothing to prevent syncing the txg while the 1883 * waiter is on the i_sync_list. This normally doesn't 1884 * happen because spa_sync() is slower than zil_commit(), 1885 * but if zil_commit() calls txg_wait_synced() (e.g. 1886 * because zil_create() or zil_commit_writer_stall() is 1887 * called) we will hit this case. 1888 */ 1889 if (itx->itx_lr.lrc_txtype == TX_COMMIT) 1890 zil_commit_waiter_skip(itx->itx_private); 1891 1892 list_remove(list, itx); 1893 zil_itx_destroy(itx); 1894 } 1895 1896 cookie = NULL; 1897 t = &itxs->i_async_tree; 1898 while ((ian = avl_destroy_nodes(t, &cookie)) != NULL) { 1899 list = &ian->ia_list; 1900 while ((itx = list_head(list)) != NULL) { 1901 list_remove(list, itx); 1902 /* commit itxs should never be on the async lists. */ 1903 ASSERT3U(itx->itx_lr.lrc_txtype, !=, TX_COMMIT); 1904 zil_itx_destroy(itx); 1905 } 1906 list_destroy(list); 1907 kmem_free(ian, sizeof (itx_async_node_t)); 1908 } 1909 avl_destroy(t); 1910 1911 kmem_free(itxs, sizeof (itxs_t)); 1912 } 1913 1914 static int 1915 zil_aitx_compare(const void *x1, const void *x2) 1916 { 1917 const uint64_t o1 = ((itx_async_node_t *)x1)->ia_foid; 1918 const uint64_t o2 = ((itx_async_node_t *)x2)->ia_foid; 1919 1920 return (TREE_CMP(o1, o2)); 1921 } 1922 1923 /* 1924 * Remove all async itx with the given oid. 1925 */ 1926 void 1927 zil_remove_async(zilog_t *zilog, uint64_t oid) 1928 { 1929 uint64_t otxg, txg; 1930 itx_async_node_t *ian; 1931 avl_tree_t *t; 1932 avl_index_t where; 1933 list_t clean_list; 1934 itx_t *itx; 1935 1936 ASSERT(oid != 0); 1937 list_create(&clean_list, sizeof (itx_t), offsetof(itx_t, itx_node)); 1938 1939 if (spa_freeze_txg(zilog->zl_spa) != UINT64_MAX) /* ziltest support */ 1940 otxg = ZILTEST_TXG; 1941 else 1942 otxg = spa_last_synced_txg(zilog->zl_spa) + 1; 1943 1944 for (txg = otxg; txg < (otxg + TXG_CONCURRENT_STATES); txg++) { 1945 itxg_t *itxg = &zilog->zl_itxg[txg & TXG_MASK]; 1946 1947 mutex_enter(&itxg->itxg_lock); 1948 if (itxg->itxg_txg != txg) { 1949 mutex_exit(&itxg->itxg_lock); 1950 continue; 1951 } 1952 1953 /* 1954 * Locate the object node and append its list. 1955 */ 1956 t = &itxg->itxg_itxs->i_async_tree; 1957 ian = avl_find(t, &oid, &where); 1958 if (ian != NULL) 1959 list_move_tail(&clean_list, &ian->ia_list); 1960 mutex_exit(&itxg->itxg_lock); 1961 } 1962 while ((itx = list_head(&clean_list)) != NULL) { 1963 list_remove(&clean_list, itx); 1964 /* commit itxs should never be on the async lists. */ 1965 ASSERT3U(itx->itx_lr.lrc_txtype, !=, TX_COMMIT); 1966 zil_itx_destroy(itx); 1967 } 1968 list_destroy(&clean_list); 1969 } 1970 1971 void 1972 zil_itx_assign(zilog_t *zilog, itx_t *itx, dmu_tx_t *tx) 1973 { 1974 uint64_t txg; 1975 itxg_t *itxg; 1976 itxs_t *itxs, *clean = NULL; 1977 1978 /* 1979 * Ensure the data of a renamed file is committed before the rename. 1980 */ 1981 if ((itx->itx_lr.lrc_txtype & ~TX_CI) == TX_RENAME) 1982 zil_async_to_sync(zilog, itx->itx_oid); 1983 1984 if (spa_freeze_txg(zilog->zl_spa) != UINT64_MAX) 1985 txg = ZILTEST_TXG; 1986 else 1987 txg = dmu_tx_get_txg(tx); 1988 1989 itxg = &zilog->zl_itxg[txg & TXG_MASK]; 1990 mutex_enter(&itxg->itxg_lock); 1991 itxs = itxg->itxg_itxs; 1992 if (itxg->itxg_txg != txg) { 1993 if (itxs != NULL) { 1994 /* 1995 * The zil_clean callback hasn't got around to cleaning 1996 * this itxg. Save the itxs for release below. 1997 * This should be rare. 1998 */ 1999 zfs_dbgmsg("zil_itx_assign: missed itx cleanup for " 2000 "txg %llu", (u_longlong_t)itxg->itxg_txg); 2001 clean = itxg->itxg_itxs; 2002 } 2003 itxg->itxg_txg = txg; 2004 itxs = itxg->itxg_itxs = kmem_zalloc(sizeof (itxs_t), 2005 KM_SLEEP); 2006 2007 list_create(&itxs->i_sync_list, sizeof (itx_t), 2008 offsetof(itx_t, itx_node)); 2009 avl_create(&itxs->i_async_tree, zil_aitx_compare, 2010 sizeof (itx_async_node_t), 2011 offsetof(itx_async_node_t, ia_node)); 2012 } 2013 if (itx->itx_sync) { 2014 list_insert_tail(&itxs->i_sync_list, itx); 2015 } else { 2016 avl_tree_t *t = &itxs->i_async_tree; 2017 uint64_t foid = 2018 LR_FOID_GET_OBJ(((lr_ooo_t *)&itx->itx_lr)->lr_foid); 2019 itx_async_node_t *ian; 2020 avl_index_t where; 2021 2022 ian = avl_find(t, &foid, &where); 2023 if (ian == NULL) { 2024 ian = kmem_alloc(sizeof (itx_async_node_t), 2025 KM_SLEEP); 2026 list_create(&ian->ia_list, sizeof (itx_t), 2027 offsetof(itx_t, itx_node)); 2028 ian->ia_foid = foid; 2029 avl_insert(t, ian, where); 2030 } 2031 list_insert_tail(&ian->ia_list, itx); 2032 } 2033 2034 itx->itx_lr.lrc_txg = dmu_tx_get_txg(tx); 2035 2036 /* 2037 * We don't want to dirty the ZIL using ZILTEST_TXG, because 2038 * zil_clean() will never be called using ZILTEST_TXG. Thus, we 2039 * need to be careful to always dirty the ZIL using the "real" 2040 * TXG (not itxg_txg) even when the SPA is frozen. 2041 */ 2042 zilog_dirty(zilog, dmu_tx_get_txg(tx)); 2043 mutex_exit(&itxg->itxg_lock); 2044 2045 /* Release the old itxs now we've dropped the lock */ 2046 if (clean != NULL) 2047 zil_itxg_clean(clean); 2048 } 2049 2050 /* 2051 * If there are any in-memory intent log transactions which have now been 2052 * synced then start up a taskq to free them. We should only do this after we 2053 * have written out the uberblocks (i.e. txg has been committed) so that 2054 * don't inadvertently clean out in-memory log records that would be required 2055 * by zil_commit(). 2056 */ 2057 void 2058 zil_clean(zilog_t *zilog, uint64_t synced_txg) 2059 { 2060 itxg_t *itxg = &zilog->zl_itxg[synced_txg & TXG_MASK]; 2061 itxs_t *clean_me; 2062 2063 ASSERT3U(synced_txg, <, ZILTEST_TXG); 2064 2065 mutex_enter(&itxg->itxg_lock); 2066 if (itxg->itxg_itxs == NULL || itxg->itxg_txg == ZILTEST_TXG) { 2067 mutex_exit(&itxg->itxg_lock); 2068 return; 2069 } 2070 ASSERT3U(itxg->itxg_txg, <=, synced_txg); 2071 ASSERT3U(itxg->itxg_txg, !=, 0); 2072 clean_me = itxg->itxg_itxs; 2073 itxg->itxg_itxs = NULL; 2074 itxg->itxg_txg = 0; 2075 mutex_exit(&itxg->itxg_lock); 2076 /* 2077 * Preferably start a task queue to free up the old itxs but 2078 * if taskq_dispatch can't allocate resources to do that then 2079 * free it in-line. This should be rare. Note, using TQ_SLEEP 2080 * created a bad performance problem. 2081 */ 2082 ASSERT3P(zilog->zl_dmu_pool, !=, NULL); 2083 ASSERT3P(zilog->zl_dmu_pool->dp_zil_clean_taskq, !=, NULL); 2084 taskqid_t id = taskq_dispatch(zilog->zl_dmu_pool->dp_zil_clean_taskq, 2085 zil_itxg_clean, clean_me, TQ_NOSLEEP); 2086 if (id == TASKQID_INVALID) 2087 zil_itxg_clean(clean_me); 2088 } 2089 2090 /* 2091 * This function will traverse the queue of itxs that need to be 2092 * committed, and move them onto the ZIL's zl_itx_commit_list. 2093 */ 2094 static void 2095 zil_get_commit_list(zilog_t *zilog) 2096 { 2097 uint64_t otxg, txg; 2098 list_t *commit_list = &zilog->zl_itx_commit_list; 2099 2100 ASSERT(MUTEX_HELD(&zilog->zl_issuer_lock)); 2101 2102 if (spa_freeze_txg(zilog->zl_spa) != UINT64_MAX) /* ziltest support */ 2103 otxg = ZILTEST_TXG; 2104 else 2105 otxg = spa_last_synced_txg(zilog->zl_spa) + 1; 2106 2107 /* 2108 * This is inherently racy, since there is nothing to prevent 2109 * the last synced txg from changing. That's okay since we'll 2110 * only commit things in the future. 2111 */ 2112 for (txg = otxg; txg < (otxg + TXG_CONCURRENT_STATES); txg++) { 2113 itxg_t *itxg = &zilog->zl_itxg[txg & TXG_MASK]; 2114 2115 mutex_enter(&itxg->itxg_lock); 2116 if (itxg->itxg_txg != txg) { 2117 mutex_exit(&itxg->itxg_lock); 2118 continue; 2119 } 2120 2121 /* 2122 * If we're adding itx records to the zl_itx_commit_list, 2123 * then the zil better be dirty in this "txg". We can assert 2124 * that here since we're holding the itxg_lock which will 2125 * prevent spa_sync from cleaning it. Once we add the itxs 2126 * to the zl_itx_commit_list we must commit it to disk even 2127 * if it's unnecessary (i.e. the txg was synced). 2128 */ 2129 ASSERT(zilog_is_dirty_in_txg(zilog, txg) || 2130 spa_freeze_txg(zilog->zl_spa) != UINT64_MAX); 2131 list_move_tail(commit_list, &itxg->itxg_itxs->i_sync_list); 2132 2133 mutex_exit(&itxg->itxg_lock); 2134 } 2135 } 2136 2137 /* 2138 * Move the async itxs for a specified object to commit into sync lists. 2139 */ 2140 void 2141 zil_async_to_sync(zilog_t *zilog, uint64_t foid) 2142 { 2143 uint64_t otxg, txg; 2144 itx_async_node_t *ian; 2145 avl_tree_t *t; 2146 avl_index_t where; 2147 2148 if (spa_freeze_txg(zilog->zl_spa) != UINT64_MAX) /* ziltest support */ 2149 otxg = ZILTEST_TXG; 2150 else 2151 otxg = spa_last_synced_txg(zilog->zl_spa) + 1; 2152 2153 /* 2154 * This is inherently racy, since there is nothing to prevent 2155 * the last synced txg from changing. 2156 */ 2157 for (txg = otxg; txg < (otxg + TXG_CONCURRENT_STATES); txg++) { 2158 itxg_t *itxg = &zilog->zl_itxg[txg & TXG_MASK]; 2159 2160 mutex_enter(&itxg->itxg_lock); 2161 if (itxg->itxg_txg != txg) { 2162 mutex_exit(&itxg->itxg_lock); 2163 continue; 2164 } 2165 2166 /* 2167 * If a foid is specified then find that node and append its 2168 * list. Otherwise walk the tree appending all the lists 2169 * to the sync list. We add to the end rather than the 2170 * beginning to ensure the create has happened. 2171 */ 2172 t = &itxg->itxg_itxs->i_async_tree; 2173 if (foid != 0) { 2174 ian = avl_find(t, &foid, &where); 2175 if (ian != NULL) { 2176 list_move_tail(&itxg->itxg_itxs->i_sync_list, 2177 &ian->ia_list); 2178 } 2179 } else { 2180 void *cookie = NULL; 2181 2182 while ((ian = avl_destroy_nodes(t, &cookie)) != NULL) { 2183 list_move_tail(&itxg->itxg_itxs->i_sync_list, 2184 &ian->ia_list); 2185 list_destroy(&ian->ia_list); 2186 kmem_free(ian, sizeof (itx_async_node_t)); 2187 } 2188 } 2189 mutex_exit(&itxg->itxg_lock); 2190 } 2191 } 2192 2193 /* 2194 * This function will prune commit itxs that are at the head of the 2195 * commit list (it won't prune past the first non-commit itx), and 2196 * either: a) attach them to the last lwb that's still pending 2197 * completion, or b) skip them altogether. 2198 * 2199 * This is used as a performance optimization to prevent commit itxs 2200 * from generating new lwbs when it's unnecessary to do so. 2201 */ 2202 static void 2203 zil_prune_commit_list(zilog_t *zilog) 2204 { 2205 itx_t *itx; 2206 2207 ASSERT(MUTEX_HELD(&zilog->zl_issuer_lock)); 2208 2209 while ((itx = list_head(&zilog->zl_itx_commit_list)) != NULL) { 2210 lr_t *lrc = &itx->itx_lr; 2211 if (lrc->lrc_txtype != TX_COMMIT) 2212 break; 2213 2214 mutex_enter(&zilog->zl_lock); 2215 2216 lwb_t *last_lwb = zilog->zl_last_lwb_opened; 2217 if (last_lwb == NULL || 2218 last_lwb->lwb_state == LWB_STATE_FLUSH_DONE) { 2219 /* 2220 * All of the itxs this waiter was waiting on 2221 * must have already completed (or there were 2222 * never any itx's for it to wait on), so it's 2223 * safe to skip this waiter and mark it done. 2224 */ 2225 zil_commit_waiter_skip(itx->itx_private); 2226 } else { 2227 zil_commit_waiter_link_lwb(itx->itx_private, last_lwb); 2228 itx->itx_private = NULL; 2229 } 2230 2231 mutex_exit(&zilog->zl_lock); 2232 2233 list_remove(&zilog->zl_itx_commit_list, itx); 2234 zil_itx_destroy(itx); 2235 } 2236 2237 IMPLY(itx != NULL, itx->itx_lr.lrc_txtype != TX_COMMIT); 2238 } 2239 2240 static void 2241 zil_commit_writer_stall(zilog_t *zilog) 2242 { 2243 /* 2244 * When zio_alloc_zil() fails to allocate the next lwb block on 2245 * disk, we must call txg_wait_synced() to ensure all of the 2246 * lwbs in the zilog's zl_lwb_list are synced and then freed (in 2247 * zil_sync()), such that any subsequent ZIL writer (i.e. a call 2248 * to zil_process_commit_list()) will have to call zil_create(), 2249 * and start a new ZIL chain. 2250 * 2251 * Since zil_alloc_zil() failed, the lwb that was previously 2252 * issued does not have a pointer to the "next" lwb on disk. 2253 * Thus, if another ZIL writer thread was to allocate the "next" 2254 * on-disk lwb, that block could be leaked in the event of a 2255 * crash (because the previous lwb on-disk would not point to 2256 * it). 2257 * 2258 * We must hold the zilog's zl_issuer_lock while we do this, to 2259 * ensure no new threads enter zil_process_commit_list() until 2260 * all lwb's in the zl_lwb_list have been synced and freed 2261 * (which is achieved via the txg_wait_synced() call). 2262 */ 2263 ASSERT(MUTEX_HELD(&zilog->zl_issuer_lock)); 2264 txg_wait_synced(zilog->zl_dmu_pool, 0); 2265 ASSERT3P(list_tail(&zilog->zl_lwb_list), ==, NULL); 2266 } 2267 2268 /* 2269 * This function will traverse the commit list, creating new lwbs as 2270 * needed, and committing the itxs from the commit list to these newly 2271 * created lwbs. Additionally, as a new lwb is created, the previous 2272 * lwb will be issued to the zio layer to be written to disk. 2273 */ 2274 static void 2275 zil_process_commit_list(zilog_t *zilog) 2276 { 2277 spa_t *spa = zilog->zl_spa; 2278 list_t nolwb_itxs; 2279 list_t nolwb_waiters; 2280 lwb_t *lwb; 2281 itx_t *itx; 2282 2283 ASSERT(MUTEX_HELD(&zilog->zl_issuer_lock)); 2284 2285 /* 2286 * Return if there's nothing to commit before we dirty the fs by 2287 * calling zil_create(). 2288 */ 2289 if (list_head(&zilog->zl_itx_commit_list) == NULL) 2290 return; 2291 2292 list_create(&nolwb_itxs, sizeof (itx_t), offsetof(itx_t, itx_node)); 2293 list_create(&nolwb_waiters, sizeof (zil_commit_waiter_t), 2294 offsetof(zil_commit_waiter_t, zcw_node)); 2295 2296 lwb = list_tail(&zilog->zl_lwb_list); 2297 if (lwb == NULL) { 2298 lwb = zil_create(zilog); 2299 } else { 2300 ASSERT3S(lwb->lwb_state, !=, LWB_STATE_ISSUED); 2301 ASSERT3S(lwb->lwb_state, !=, LWB_STATE_WRITE_DONE); 2302 ASSERT3S(lwb->lwb_state, !=, LWB_STATE_FLUSH_DONE); 2303 } 2304 2305 while ((itx = list_head(&zilog->zl_itx_commit_list)) != NULL) { 2306 lr_t *lrc = &itx->itx_lr; 2307 uint64_t txg = lrc->lrc_txg; 2308 2309 ASSERT3U(txg, !=, 0); 2310 2311 if (lrc->lrc_txtype == TX_COMMIT) { 2312 DTRACE_PROBE2(zil__process__commit__itx, 2313 zilog_t *, zilog, itx_t *, itx); 2314 } else { 2315 DTRACE_PROBE2(zil__process__normal__itx, 2316 zilog_t *, zilog, itx_t *, itx); 2317 } 2318 2319 list_remove(&zilog->zl_itx_commit_list, itx); 2320 2321 boolean_t synced = txg <= spa_last_synced_txg(spa); 2322 boolean_t frozen = txg > spa_freeze_txg(spa); 2323 2324 /* 2325 * If the txg of this itx has already been synced out, then 2326 * we don't need to commit this itx to an lwb. This is 2327 * because the data of this itx will have already been 2328 * written to the main pool. This is inherently racy, and 2329 * it's still ok to commit an itx whose txg has already 2330 * been synced; this will result in a write that's 2331 * unnecessary, but will do no harm. 2332 * 2333 * With that said, we always want to commit TX_COMMIT itxs 2334 * to an lwb, regardless of whether or not that itx's txg 2335 * has been synced out. We do this to ensure any OPENED lwb 2336 * will always have at least one zil_commit_waiter_t linked 2337 * to the lwb. 2338 * 2339 * As a counter-example, if we skipped TX_COMMIT itx's 2340 * whose txg had already been synced, the following 2341 * situation could occur if we happened to be racing with 2342 * spa_sync: 2343 * 2344 * 1. We commit a non-TX_COMMIT itx to an lwb, where the 2345 * itx's txg is 10 and the last synced txg is 9. 2346 * 2. spa_sync finishes syncing out txg 10. 2347 * 3. We move to the next itx in the list, it's a TX_COMMIT 2348 * whose txg is 10, so we skip it rather than committing 2349 * it to the lwb used in (1). 2350 * 2351 * If the itx that is skipped in (3) is the last TX_COMMIT 2352 * itx in the commit list, than it's possible for the lwb 2353 * used in (1) to remain in the OPENED state indefinitely. 2354 * 2355 * To prevent the above scenario from occurring, ensuring 2356 * that once an lwb is OPENED it will transition to ISSUED 2357 * and eventually DONE, we always commit TX_COMMIT itx's to 2358 * an lwb here, even if that itx's txg has already been 2359 * synced. 2360 * 2361 * Finally, if the pool is frozen, we _always_ commit the 2362 * itx. The point of freezing the pool is to prevent data 2363 * from being written to the main pool via spa_sync, and 2364 * instead rely solely on the ZIL to persistently store the 2365 * data; i.e. when the pool is frozen, the last synced txg 2366 * value can't be trusted. 2367 */ 2368 if (frozen || !synced || lrc->lrc_txtype == TX_COMMIT) { 2369 if (lwb != NULL) { 2370 lwb = zil_lwb_commit(zilog, itx, lwb); 2371 2372 if (lwb == NULL) 2373 list_insert_tail(&nolwb_itxs, itx); 2374 else 2375 list_insert_tail(&lwb->lwb_itxs, itx); 2376 } else { 2377 if (lrc->lrc_txtype == TX_COMMIT) { 2378 zil_commit_waiter_link_nolwb( 2379 itx->itx_private, &nolwb_waiters); 2380 } 2381 2382 list_insert_tail(&nolwb_itxs, itx); 2383 } 2384 } else { 2385 ASSERT3S(lrc->lrc_txtype, !=, TX_COMMIT); 2386 zil_itx_destroy(itx); 2387 } 2388 } 2389 2390 if (lwb == NULL) { 2391 /* 2392 * This indicates zio_alloc_zil() failed to allocate the 2393 * "next" lwb on-disk. When this happens, we must stall 2394 * the ZIL write pipeline; see the comment within 2395 * zil_commit_writer_stall() for more details. 2396 */ 2397 zil_commit_writer_stall(zilog); 2398 2399 /* 2400 * Additionally, we have to signal and mark the "nolwb" 2401 * waiters as "done" here, since without an lwb, we 2402 * can't do this via zil_lwb_flush_vdevs_done() like 2403 * normal. 2404 */ 2405 zil_commit_waiter_t *zcw; 2406 while ((zcw = list_head(&nolwb_waiters)) != NULL) { 2407 zil_commit_waiter_skip(zcw); 2408 list_remove(&nolwb_waiters, zcw); 2409 } 2410 2411 /* 2412 * And finally, we have to destroy the itx's that 2413 * couldn't be committed to an lwb; this will also call 2414 * the itx's callback if one exists for the itx. 2415 */ 2416 while ((itx = list_head(&nolwb_itxs)) != NULL) { 2417 list_remove(&nolwb_itxs, itx); 2418 zil_itx_destroy(itx); 2419 } 2420 } else { 2421 ASSERT(list_is_empty(&nolwb_waiters)); 2422 ASSERT3P(lwb, !=, NULL); 2423 ASSERT3S(lwb->lwb_state, !=, LWB_STATE_ISSUED); 2424 ASSERT3S(lwb->lwb_state, !=, LWB_STATE_WRITE_DONE); 2425 ASSERT3S(lwb->lwb_state, !=, LWB_STATE_FLUSH_DONE); 2426 2427 /* 2428 * At this point, the ZIL block pointed at by the "lwb" 2429 * variable is in one of the following states: "closed" 2430 * or "open". 2431 * 2432 * If it's "closed", then no itxs have been committed to 2433 * it, so there's no point in issuing its zio (i.e. it's 2434 * "empty"). 2435 * 2436 * If it's "open", then it contains one or more itxs that 2437 * eventually need to be committed to stable storage. In 2438 * this case we intentionally do not issue the lwb's zio 2439 * to disk yet, and instead rely on one of the following 2440 * two mechanisms for issuing the zio: 2441 * 2442 * 1. Ideally, there will be more ZIL activity occurring 2443 * on the system, such that this function will be 2444 * immediately called again (not necessarily by the same 2445 * thread) and this lwb's zio will be issued via 2446 * zil_lwb_commit(). This way, the lwb is guaranteed to 2447 * be "full" when it is issued to disk, and we'll make 2448 * use of the lwb's size the best we can. 2449 * 2450 * 2. If there isn't sufficient ZIL activity occurring on 2451 * the system, such that this lwb's zio isn't issued via 2452 * zil_lwb_commit(), zil_commit_waiter() will issue the 2453 * lwb's zio. If this occurs, the lwb is not guaranteed 2454 * to be "full" by the time its zio is issued, and means 2455 * the size of the lwb was "too large" given the amount 2456 * of ZIL activity occurring on the system at that time. 2457 * 2458 * We do this for a couple of reasons: 2459 * 2460 * 1. To try and reduce the number of IOPs needed to 2461 * write the same number of itxs. If an lwb has space 2462 * available in its buffer for more itxs, and more itxs 2463 * will be committed relatively soon (relative to the 2464 * latency of performing a write), then it's beneficial 2465 * to wait for these "next" itxs. This way, more itxs 2466 * can be committed to stable storage with fewer writes. 2467 * 2468 * 2. To try and use the largest lwb block size that the 2469 * incoming rate of itxs can support. Again, this is to 2470 * try and pack as many itxs into as few lwbs as 2471 * possible, without significantly impacting the latency 2472 * of each individual itx. 2473 */ 2474 } 2475 } 2476 2477 /* 2478 * This function is responsible for ensuring the passed in commit waiter 2479 * (and associated commit itx) is committed to an lwb. If the waiter is 2480 * not already committed to an lwb, all itxs in the zilog's queue of 2481 * itxs will be processed. The assumption is the passed in waiter's 2482 * commit itx will found in the queue just like the other non-commit 2483 * itxs, such that when the entire queue is processed, the waiter will 2484 * have been committed to an lwb. 2485 * 2486 * The lwb associated with the passed in waiter is not guaranteed to 2487 * have been issued by the time this function completes. If the lwb is 2488 * not issued, we rely on future calls to zil_commit_writer() to issue 2489 * the lwb, or the timeout mechanism found in zil_commit_waiter(). 2490 */ 2491 static void 2492 zil_commit_writer(zilog_t *zilog, zil_commit_waiter_t *zcw) 2493 { 2494 ASSERT(!MUTEX_HELD(&zilog->zl_lock)); 2495 ASSERT(spa_writeable(zilog->zl_spa)); 2496 2497 mutex_enter(&zilog->zl_issuer_lock); 2498 2499 if (zcw->zcw_lwb != NULL || zcw->zcw_done) { 2500 /* 2501 * It's possible that, while we were waiting to acquire 2502 * the "zl_issuer_lock", another thread committed this 2503 * waiter to an lwb. If that occurs, we bail out early, 2504 * without processing any of the zilog's queue of itxs. 2505 * 2506 * On certain workloads and system configurations, the 2507 * "zl_issuer_lock" can become highly contended. In an 2508 * attempt to reduce this contention, we immediately drop 2509 * the lock if the waiter has already been processed. 2510 * 2511 * We've measured this optimization to reduce CPU spent 2512 * contending on this lock by up to 5%, using a system 2513 * with 32 CPUs, low latency storage (~50 usec writes), 2514 * and 1024 threads performing sync writes. 2515 */ 2516 goto out; 2517 } 2518 2519 ZIL_STAT_BUMP(zil_commit_writer_count); 2520 2521 zil_get_commit_list(zilog); 2522 zil_prune_commit_list(zilog); 2523 zil_process_commit_list(zilog); 2524 2525 out: 2526 mutex_exit(&zilog->zl_issuer_lock); 2527 } 2528 2529 static void 2530 zil_commit_waiter_timeout(zilog_t *zilog, zil_commit_waiter_t *zcw) 2531 { 2532 ASSERT(!MUTEX_HELD(&zilog->zl_issuer_lock)); 2533 ASSERT(MUTEX_HELD(&zcw->zcw_lock)); 2534 ASSERT3B(zcw->zcw_done, ==, B_FALSE); 2535 2536 lwb_t *lwb = zcw->zcw_lwb; 2537 ASSERT3P(lwb, !=, NULL); 2538 ASSERT3S(lwb->lwb_state, !=, LWB_STATE_CLOSED); 2539 2540 /* 2541 * If the lwb has already been issued by another thread, we can 2542 * immediately return since there's no work to be done (the 2543 * point of this function is to issue the lwb). Additionally, we 2544 * do this prior to acquiring the zl_issuer_lock, to avoid 2545 * acquiring it when it's not necessary to do so. 2546 */ 2547 if (lwb->lwb_state == LWB_STATE_ISSUED || 2548 lwb->lwb_state == LWB_STATE_WRITE_DONE || 2549 lwb->lwb_state == LWB_STATE_FLUSH_DONE) 2550 return; 2551 2552 /* 2553 * In order to call zil_lwb_write_issue() we must hold the 2554 * zilog's "zl_issuer_lock". We can't simply acquire that lock, 2555 * since we're already holding the commit waiter's "zcw_lock", 2556 * and those two locks are acquired in the opposite order 2557 * elsewhere. 2558 */ 2559 mutex_exit(&zcw->zcw_lock); 2560 mutex_enter(&zilog->zl_issuer_lock); 2561 mutex_enter(&zcw->zcw_lock); 2562 2563 /* 2564 * Since we just dropped and re-acquired the commit waiter's 2565 * lock, we have to re-check to see if the waiter was marked 2566 * "done" during that process. If the waiter was marked "done", 2567 * the "lwb" pointer is no longer valid (it can be free'd after 2568 * the waiter is marked "done"), so without this check we could 2569 * wind up with a use-after-free error below. 2570 */ 2571 if (zcw->zcw_done) 2572 goto out; 2573 2574 ASSERT3P(lwb, ==, zcw->zcw_lwb); 2575 2576 /* 2577 * We've already checked this above, but since we hadn't acquired 2578 * the zilog's zl_issuer_lock, we have to perform this check a 2579 * second time while holding the lock. 2580 * 2581 * We don't need to hold the zl_lock since the lwb cannot transition 2582 * from OPENED to ISSUED while we hold the zl_issuer_lock. The lwb 2583 * _can_ transition from ISSUED to DONE, but it's OK to race with 2584 * that transition since we treat the lwb the same, whether it's in 2585 * the ISSUED or DONE states. 2586 * 2587 * The important thing, is we treat the lwb differently depending on 2588 * if it's ISSUED or OPENED, and block any other threads that might 2589 * attempt to issue this lwb. For that reason we hold the 2590 * zl_issuer_lock when checking the lwb_state; we must not call 2591 * zil_lwb_write_issue() if the lwb had already been issued. 2592 * 2593 * See the comment above the lwb_state_t structure definition for 2594 * more details on the lwb states, and locking requirements. 2595 */ 2596 if (lwb->lwb_state == LWB_STATE_ISSUED || 2597 lwb->lwb_state == LWB_STATE_WRITE_DONE || 2598 lwb->lwb_state == LWB_STATE_FLUSH_DONE) 2599 goto out; 2600 2601 ASSERT3S(lwb->lwb_state, ==, LWB_STATE_OPENED); 2602 2603 /* 2604 * As described in the comments above zil_commit_waiter() and 2605 * zil_process_commit_list(), we need to issue this lwb's zio 2606 * since we've reached the commit waiter's timeout and it still 2607 * hasn't been issued. 2608 */ 2609 lwb_t *nlwb = zil_lwb_write_issue(zilog, lwb); 2610 2611 IMPLY(nlwb != NULL, lwb->lwb_state != LWB_STATE_OPENED); 2612 2613 /* 2614 * Since the lwb's zio hadn't been issued by the time this thread 2615 * reached its timeout, we reset the zilog's "zl_cur_used" field 2616 * to influence the zil block size selection algorithm. 2617 * 2618 * By having to issue the lwb's zio here, it means the size of the 2619 * lwb was too large, given the incoming throughput of itxs. By 2620 * setting "zl_cur_used" to zero, we communicate this fact to the 2621 * block size selection algorithm, so it can take this information 2622 * into account, and potentially select a smaller size for the 2623 * next lwb block that is allocated. 2624 */ 2625 zilog->zl_cur_used = 0; 2626 2627 if (nlwb == NULL) { 2628 /* 2629 * When zil_lwb_write_issue() returns NULL, this 2630 * indicates zio_alloc_zil() failed to allocate the 2631 * "next" lwb on-disk. When this occurs, the ZIL write 2632 * pipeline must be stalled; see the comment within the 2633 * zil_commit_writer_stall() function for more details. 2634 * 2635 * We must drop the commit waiter's lock prior to 2636 * calling zil_commit_writer_stall() or else we can wind 2637 * up with the following deadlock: 2638 * 2639 * - This thread is waiting for the txg to sync while 2640 * holding the waiter's lock; txg_wait_synced() is 2641 * used within txg_commit_writer_stall(). 2642 * 2643 * - The txg can't sync because it is waiting for this 2644 * lwb's zio callback to call dmu_tx_commit(). 2645 * 2646 * - The lwb's zio callback can't call dmu_tx_commit() 2647 * because it's blocked trying to acquire the waiter's 2648 * lock, which occurs prior to calling dmu_tx_commit() 2649 */ 2650 mutex_exit(&zcw->zcw_lock); 2651 zil_commit_writer_stall(zilog); 2652 mutex_enter(&zcw->zcw_lock); 2653 } 2654 2655 out: 2656 mutex_exit(&zilog->zl_issuer_lock); 2657 ASSERT(MUTEX_HELD(&zcw->zcw_lock)); 2658 } 2659 2660 /* 2661 * This function is responsible for performing the following two tasks: 2662 * 2663 * 1. its primary responsibility is to block until the given "commit 2664 * waiter" is considered "done". 2665 * 2666 * 2. its secondary responsibility is to issue the zio for the lwb that 2667 * the given "commit waiter" is waiting on, if this function has 2668 * waited "long enough" and the lwb is still in the "open" state. 2669 * 2670 * Given a sufficient amount of itxs being generated and written using 2671 * the ZIL, the lwb's zio will be issued via the zil_lwb_commit() 2672 * function. If this does not occur, this secondary responsibility will 2673 * ensure the lwb is issued even if there is not other synchronous 2674 * activity on the system. 2675 * 2676 * For more details, see zil_process_commit_list(); more specifically, 2677 * the comment at the bottom of that function. 2678 */ 2679 static void 2680 zil_commit_waiter(zilog_t *zilog, zil_commit_waiter_t *zcw) 2681 { 2682 ASSERT(!MUTEX_HELD(&zilog->zl_lock)); 2683 ASSERT(!MUTEX_HELD(&zilog->zl_issuer_lock)); 2684 ASSERT(spa_writeable(zilog->zl_spa)); 2685 2686 mutex_enter(&zcw->zcw_lock); 2687 2688 /* 2689 * The timeout is scaled based on the lwb latency to avoid 2690 * significantly impacting the latency of each individual itx. 2691 * For more details, see the comment at the bottom of the 2692 * zil_process_commit_list() function. 2693 */ 2694 int pct = MAX(zfs_commit_timeout_pct, 1); 2695 hrtime_t sleep = (zilog->zl_last_lwb_latency * pct) / 100; 2696 hrtime_t wakeup = gethrtime() + sleep; 2697 boolean_t timedout = B_FALSE; 2698 2699 while (!zcw->zcw_done) { 2700 ASSERT(MUTEX_HELD(&zcw->zcw_lock)); 2701 2702 lwb_t *lwb = zcw->zcw_lwb; 2703 2704 /* 2705 * Usually, the waiter will have a non-NULL lwb field here, 2706 * but it's possible for it to be NULL as a result of 2707 * zil_commit() racing with spa_sync(). 2708 * 2709 * When zil_clean() is called, it's possible for the itxg 2710 * list (which may be cleaned via a taskq) to contain 2711 * commit itxs. When this occurs, the commit waiters linked 2712 * off of these commit itxs will not be committed to an 2713 * lwb. Additionally, these commit waiters will not be 2714 * marked done until zil_commit_waiter_skip() is called via 2715 * zil_itxg_clean(). 2716 * 2717 * Thus, it's possible for this commit waiter (i.e. the 2718 * "zcw" variable) to be found in this "in between" state; 2719 * where it's "zcw_lwb" field is NULL, and it hasn't yet 2720 * been skipped, so it's "zcw_done" field is still B_FALSE. 2721 */ 2722 IMPLY(lwb != NULL, lwb->lwb_state != LWB_STATE_CLOSED); 2723 2724 if (lwb != NULL && lwb->lwb_state == LWB_STATE_OPENED) { 2725 ASSERT3B(timedout, ==, B_FALSE); 2726 2727 /* 2728 * If the lwb hasn't been issued yet, then we 2729 * need to wait with a timeout, in case this 2730 * function needs to issue the lwb after the 2731 * timeout is reached; responsibility (2) from 2732 * the comment above this function. 2733 */ 2734 int rc = cv_timedwait_hires(&zcw->zcw_cv, 2735 &zcw->zcw_lock, wakeup, USEC2NSEC(1), 2736 CALLOUT_FLAG_ABSOLUTE); 2737 2738 if (rc != -1 || zcw->zcw_done) 2739 continue; 2740 2741 timedout = B_TRUE; 2742 zil_commit_waiter_timeout(zilog, zcw); 2743 2744 if (!zcw->zcw_done) { 2745 /* 2746 * If the commit waiter has already been 2747 * marked "done", it's possible for the 2748 * waiter's lwb structure to have already 2749 * been freed. Thus, we can only reliably 2750 * make these assertions if the waiter 2751 * isn't done. 2752 */ 2753 ASSERT3P(lwb, ==, zcw->zcw_lwb); 2754 ASSERT3S(lwb->lwb_state, !=, LWB_STATE_OPENED); 2755 } 2756 } else { 2757 /* 2758 * If the lwb isn't open, then it must have already 2759 * been issued. In that case, there's no need to 2760 * use a timeout when waiting for the lwb to 2761 * complete. 2762 * 2763 * Additionally, if the lwb is NULL, the waiter 2764 * will soon be signaled and marked done via 2765 * zil_clean() and zil_itxg_clean(), so no timeout 2766 * is required. 2767 */ 2768 2769 IMPLY(lwb != NULL, 2770 lwb->lwb_state == LWB_STATE_ISSUED || 2771 lwb->lwb_state == LWB_STATE_WRITE_DONE || 2772 lwb->lwb_state == LWB_STATE_FLUSH_DONE); 2773 cv_wait(&zcw->zcw_cv, &zcw->zcw_lock); 2774 } 2775 } 2776 2777 mutex_exit(&zcw->zcw_lock); 2778 } 2779 2780 static zil_commit_waiter_t * 2781 zil_alloc_commit_waiter(void) 2782 { 2783 zil_commit_waiter_t *zcw = kmem_cache_alloc(zil_zcw_cache, KM_SLEEP); 2784 2785 cv_init(&zcw->zcw_cv, NULL, CV_DEFAULT, NULL); 2786 mutex_init(&zcw->zcw_lock, NULL, MUTEX_DEFAULT, NULL); 2787 list_link_init(&zcw->zcw_node); 2788 zcw->zcw_lwb = NULL; 2789 zcw->zcw_done = B_FALSE; 2790 zcw->zcw_zio_error = 0; 2791 2792 return (zcw); 2793 } 2794 2795 static void 2796 zil_free_commit_waiter(zil_commit_waiter_t *zcw) 2797 { 2798 ASSERT(!list_link_active(&zcw->zcw_node)); 2799 ASSERT3P(zcw->zcw_lwb, ==, NULL); 2800 ASSERT3B(zcw->zcw_done, ==, B_TRUE); 2801 mutex_destroy(&zcw->zcw_lock); 2802 cv_destroy(&zcw->zcw_cv); 2803 kmem_cache_free(zil_zcw_cache, zcw); 2804 } 2805 2806 /* 2807 * This function is used to create a TX_COMMIT itx and assign it. This 2808 * way, it will be linked into the ZIL's list of synchronous itxs, and 2809 * then later committed to an lwb (or skipped) when 2810 * zil_process_commit_list() is called. 2811 */ 2812 static void 2813 zil_commit_itx_assign(zilog_t *zilog, zil_commit_waiter_t *zcw) 2814 { 2815 dmu_tx_t *tx = dmu_tx_create(zilog->zl_os); 2816 VERIFY0(dmu_tx_assign(tx, TXG_WAIT)); 2817 2818 itx_t *itx = zil_itx_create(TX_COMMIT, sizeof (lr_t)); 2819 itx->itx_sync = B_TRUE; 2820 itx->itx_private = zcw; 2821 2822 zil_itx_assign(zilog, itx, tx); 2823 2824 dmu_tx_commit(tx); 2825 } 2826 2827 /* 2828 * Commit ZFS Intent Log transactions (itxs) to stable storage. 2829 * 2830 * When writing ZIL transactions to the on-disk representation of the 2831 * ZIL, the itxs are committed to a Log Write Block (lwb). Multiple 2832 * itxs can be committed to a single lwb. Once a lwb is written and 2833 * committed to stable storage (i.e. the lwb is written, and vdevs have 2834 * been flushed), each itx that was committed to that lwb is also 2835 * considered to be committed to stable storage. 2836 * 2837 * When an itx is committed to an lwb, the log record (lr_t) contained 2838 * by the itx is copied into the lwb's zio buffer, and once this buffer 2839 * is written to disk, it becomes an on-disk ZIL block. 2840 * 2841 * As itxs are generated, they're inserted into the ZIL's queue of 2842 * uncommitted itxs. The semantics of zil_commit() are such that it will 2843 * block until all itxs that were in the queue when it was called, are 2844 * committed to stable storage. 2845 * 2846 * If "foid" is zero, this means all "synchronous" and "asynchronous" 2847 * itxs, for all objects in the dataset, will be committed to stable 2848 * storage prior to zil_commit() returning. If "foid" is non-zero, all 2849 * "synchronous" itxs for all objects, but only "asynchronous" itxs 2850 * that correspond to the foid passed in, will be committed to stable 2851 * storage prior to zil_commit() returning. 2852 * 2853 * Generally speaking, when zil_commit() is called, the consumer doesn't 2854 * actually care about _all_ of the uncommitted itxs. Instead, they're 2855 * simply trying to waiting for a specific itx to be committed to disk, 2856 * but the interface(s) for interacting with the ZIL don't allow such 2857 * fine-grained communication. A better interface would allow a consumer 2858 * to create and assign an itx, and then pass a reference to this itx to 2859 * zil_commit(); such that zil_commit() would return as soon as that 2860 * specific itx was committed to disk (instead of waiting for _all_ 2861 * itxs to be committed). 2862 * 2863 * When a thread calls zil_commit() a special "commit itx" will be 2864 * generated, along with a corresponding "waiter" for this commit itx. 2865 * zil_commit() will wait on this waiter's CV, such that when the waiter 2866 * is marked done, and signaled, zil_commit() will return. 2867 * 2868 * This commit itx is inserted into the queue of uncommitted itxs. This 2869 * provides an easy mechanism for determining which itxs were in the 2870 * queue prior to zil_commit() having been called, and which itxs were 2871 * added after zil_commit() was called. 2872 * 2873 * The commit it is special; it doesn't have any on-disk representation. 2874 * When a commit itx is "committed" to an lwb, the waiter associated 2875 * with it is linked onto the lwb's list of waiters. Then, when that lwb 2876 * completes, each waiter on the lwb's list is marked done and signaled 2877 * -- allowing the thread waiting on the waiter to return from zil_commit(). 2878 * 2879 * It's important to point out a few critical factors that allow us 2880 * to make use of the commit itxs, commit waiters, per-lwb lists of 2881 * commit waiters, and zio completion callbacks like we're doing: 2882 * 2883 * 1. The list of waiters for each lwb is traversed, and each commit 2884 * waiter is marked "done" and signaled, in the zio completion 2885 * callback of the lwb's zio[*]. 2886 * 2887 * * Actually, the waiters are signaled in the zio completion 2888 * callback of the root zio for the DKIOCFLUSHWRITECACHE commands 2889 * that are sent to the vdevs upon completion of the lwb zio. 2890 * 2891 * 2. When the itxs are inserted into the ZIL's queue of uncommitted 2892 * itxs, the order in which they are inserted is preserved[*]; as 2893 * itxs are added to the queue, they are added to the tail of 2894 * in-memory linked lists. 2895 * 2896 * When committing the itxs to lwbs (to be written to disk), they 2897 * are committed in the same order in which the itxs were added to 2898 * the uncommitted queue's linked list(s); i.e. the linked list of 2899 * itxs to commit is traversed from head to tail, and each itx is 2900 * committed to an lwb in that order. 2901 * 2902 * * To clarify: 2903 * 2904 * - the order of "sync" itxs is preserved w.r.t. other 2905 * "sync" itxs, regardless of the corresponding objects. 2906 * - the order of "async" itxs is preserved w.r.t. other 2907 * "async" itxs corresponding to the same object. 2908 * - the order of "async" itxs is *not* preserved w.r.t. other 2909 * "async" itxs corresponding to different objects. 2910 * - the order of "sync" itxs w.r.t. "async" itxs (or vice 2911 * versa) is *not* preserved, even for itxs that correspond 2912 * to the same object. 2913 * 2914 * For more details, see: zil_itx_assign(), zil_async_to_sync(), 2915 * zil_get_commit_list(), and zil_process_commit_list(). 2916 * 2917 * 3. The lwbs represent a linked list of blocks on disk. Thus, any 2918 * lwb cannot be considered committed to stable storage, until its 2919 * "previous" lwb is also committed to stable storage. This fact, 2920 * coupled with the fact described above, means that itxs are 2921 * committed in (roughly) the order in which they were generated. 2922 * This is essential because itxs are dependent on prior itxs. 2923 * Thus, we *must not* deem an itx as being committed to stable 2924 * storage, until *all* prior itxs have also been committed to 2925 * stable storage. 2926 * 2927 * To enforce this ordering of lwb zio's, while still leveraging as 2928 * much of the underlying storage performance as possible, we rely 2929 * on two fundamental concepts: 2930 * 2931 * 1. The creation and issuance of lwb zio's is protected by 2932 * the zilog's "zl_issuer_lock", which ensures only a single 2933 * thread is creating and/or issuing lwb's at a time 2934 * 2. The "previous" lwb is a child of the "current" lwb 2935 * (leveraging the zio parent-child dependency graph) 2936 * 2937 * By relying on this parent-child zio relationship, we can have 2938 * many lwb zio's concurrently issued to the underlying storage, 2939 * but the order in which they complete will be the same order in 2940 * which they were created. 2941 */ 2942 void 2943 zil_commit(zilog_t *zilog, uint64_t foid) 2944 { 2945 /* 2946 * We should never attempt to call zil_commit on a snapshot for 2947 * a couple of reasons: 2948 * 2949 * 1. A snapshot may never be modified, thus it cannot have any 2950 * in-flight itxs that would have modified the dataset. 2951 * 2952 * 2. By design, when zil_commit() is called, a commit itx will 2953 * be assigned to this zilog; as a result, the zilog will be 2954 * dirtied. We must not dirty the zilog of a snapshot; there's 2955 * checks in the code that enforce this invariant, and will 2956 * cause a panic if it's not upheld. 2957 */ 2958 ASSERT3B(dmu_objset_is_snapshot(zilog->zl_os), ==, B_FALSE); 2959 2960 if (zilog->zl_sync == ZFS_SYNC_DISABLED) 2961 return; 2962 2963 if (!spa_writeable(zilog->zl_spa)) { 2964 /* 2965 * If the SPA is not writable, there should never be any 2966 * pending itxs waiting to be committed to disk. If that 2967 * weren't true, we'd skip writing those itxs out, and 2968 * would break the semantics of zil_commit(); thus, we're 2969 * verifying that truth before we return to the caller. 2970 */ 2971 ASSERT(list_is_empty(&zilog->zl_lwb_list)); 2972 ASSERT3P(zilog->zl_last_lwb_opened, ==, NULL); 2973 for (int i = 0; i < TXG_SIZE; i++) 2974 ASSERT3P(zilog->zl_itxg[i].itxg_itxs, ==, NULL); 2975 return; 2976 } 2977 2978 /* 2979 * If the ZIL is suspended, we don't want to dirty it by calling 2980 * zil_commit_itx_assign() below, nor can we write out 2981 * lwbs like would be done in zil_commit_write(). Thus, we 2982 * simply rely on txg_wait_synced() to maintain the necessary 2983 * semantics, and avoid calling those functions altogether. 2984 */ 2985 if (zilog->zl_suspend > 0) { 2986 txg_wait_synced(zilog->zl_dmu_pool, 0); 2987 return; 2988 } 2989 2990 zil_commit_impl(zilog, foid); 2991 } 2992 2993 void 2994 zil_commit_impl(zilog_t *zilog, uint64_t foid) 2995 { 2996 ZIL_STAT_BUMP(zil_commit_count); 2997 2998 /* 2999 * Move the "async" itxs for the specified foid to the "sync" 3000 * queues, such that they will be later committed (or skipped) 3001 * to an lwb when zil_process_commit_list() is called. 3002 * 3003 * Since these "async" itxs must be committed prior to this 3004 * call to zil_commit returning, we must perform this operation 3005 * before we call zil_commit_itx_assign(). 3006 */ 3007 zil_async_to_sync(zilog, foid); 3008 3009 /* 3010 * We allocate a new "waiter" structure which will initially be 3011 * linked to the commit itx using the itx's "itx_private" field. 3012 * Since the commit itx doesn't represent any on-disk state, 3013 * when it's committed to an lwb, rather than copying the its 3014 * lr_t into the lwb's buffer, the commit itx's "waiter" will be 3015 * added to the lwb's list of waiters. Then, when the lwb is 3016 * committed to stable storage, each waiter in the lwb's list of 3017 * waiters will be marked "done", and signalled. 3018 * 3019 * We must create the waiter and assign the commit itx prior to 3020 * calling zil_commit_writer(), or else our specific commit itx 3021 * is not guaranteed to be committed to an lwb prior to calling 3022 * zil_commit_waiter(). 3023 */ 3024 zil_commit_waiter_t *zcw = zil_alloc_commit_waiter(); 3025 zil_commit_itx_assign(zilog, zcw); 3026 3027 zil_commit_writer(zilog, zcw); 3028 zil_commit_waiter(zilog, zcw); 3029 3030 if (zcw->zcw_zio_error != 0) { 3031 /* 3032 * If there was an error writing out the ZIL blocks that 3033 * this thread is waiting on, then we fallback to 3034 * relying on spa_sync() to write out the data this 3035 * thread is waiting on. Obviously this has performance 3036 * implications, but the expectation is for this to be 3037 * an exceptional case, and shouldn't occur often. 3038 */ 3039 DTRACE_PROBE2(zil__commit__io__error, 3040 zilog_t *, zilog, zil_commit_waiter_t *, zcw); 3041 txg_wait_synced(zilog->zl_dmu_pool, 0); 3042 } 3043 3044 zil_free_commit_waiter(zcw); 3045 } 3046 3047 /* 3048 * Called in syncing context to free committed log blocks and update log header. 3049 */ 3050 void 3051 zil_sync(zilog_t *zilog, dmu_tx_t *tx) 3052 { 3053 zil_header_t *zh = zil_header_in_syncing_context(zilog); 3054 uint64_t txg = dmu_tx_get_txg(tx); 3055 spa_t *spa = zilog->zl_spa; 3056 uint64_t *replayed_seq = &zilog->zl_replayed_seq[txg & TXG_MASK]; 3057 lwb_t *lwb; 3058 3059 /* 3060 * We don't zero out zl_destroy_txg, so make sure we don't try 3061 * to destroy it twice. 3062 */ 3063 if (spa_sync_pass(spa) != 1) 3064 return; 3065 3066 mutex_enter(&zilog->zl_lock); 3067 3068 ASSERT(zilog->zl_stop_sync == 0); 3069 3070 if (*replayed_seq != 0) { 3071 ASSERT(zh->zh_replay_seq < *replayed_seq); 3072 zh->zh_replay_seq = *replayed_seq; 3073 *replayed_seq = 0; 3074 } 3075 3076 if (zilog->zl_destroy_txg == txg) { 3077 blkptr_t blk = zh->zh_log; 3078 3079 ASSERT(list_head(&zilog->zl_lwb_list) == NULL); 3080 3081 bzero(zh, sizeof (zil_header_t)); 3082 bzero(zilog->zl_replayed_seq, sizeof (zilog->zl_replayed_seq)); 3083 3084 if (zilog->zl_keep_first) { 3085 /* 3086 * If this block was part of log chain that couldn't 3087 * be claimed because a device was missing during 3088 * zil_claim(), but that device later returns, 3089 * then this block could erroneously appear valid. 3090 * To guard against this, assign a new GUID to the new 3091 * log chain so it doesn't matter what blk points to. 3092 */ 3093 zil_init_log_chain(zilog, &blk); 3094 zh->zh_log = blk; 3095 } 3096 } 3097 3098 while ((lwb = list_head(&zilog->zl_lwb_list)) != NULL) { 3099 zh->zh_log = lwb->lwb_blk; 3100 if (lwb->lwb_buf != NULL || lwb->lwb_max_txg > txg) 3101 break; 3102 list_remove(&zilog->zl_lwb_list, lwb); 3103 zio_free(spa, txg, &lwb->lwb_blk); 3104 zil_free_lwb(zilog, lwb); 3105 3106 /* 3107 * If we don't have anything left in the lwb list then 3108 * we've had an allocation failure and we need to zero 3109 * out the zil_header blkptr so that we don't end 3110 * up freeing the same block twice. 3111 */ 3112 if (list_head(&zilog->zl_lwb_list) == NULL) 3113 BP_ZERO(&zh->zh_log); 3114 } 3115 3116 /* 3117 * Remove fastwrite on any blocks that have been pre-allocated for 3118 * the next commit. This prevents fastwrite counter pollution by 3119 * unused, long-lived LWBs. 3120 */ 3121 for (; lwb != NULL; lwb = list_next(&zilog->zl_lwb_list, lwb)) { 3122 if (lwb->lwb_fastwrite && !lwb->lwb_write_zio) { 3123 metaslab_fastwrite_unmark(zilog->zl_spa, &lwb->lwb_blk); 3124 lwb->lwb_fastwrite = 0; 3125 } 3126 } 3127 3128 mutex_exit(&zilog->zl_lock); 3129 } 3130 3131 static int 3132 zil_lwb_cons(void *vbuf, void *unused, int kmflag) 3133 { 3134 (void) unused, (void) kmflag; 3135 lwb_t *lwb = vbuf; 3136 list_create(&lwb->lwb_itxs, sizeof (itx_t), offsetof(itx_t, itx_node)); 3137 list_create(&lwb->lwb_waiters, sizeof (zil_commit_waiter_t), 3138 offsetof(zil_commit_waiter_t, zcw_node)); 3139 avl_create(&lwb->lwb_vdev_tree, zil_lwb_vdev_compare, 3140 sizeof (zil_vdev_node_t), offsetof(zil_vdev_node_t, zv_node)); 3141 mutex_init(&lwb->lwb_vdev_lock, NULL, MUTEX_DEFAULT, NULL); 3142 return (0); 3143 } 3144 3145 static void 3146 zil_lwb_dest(void *vbuf, void *unused) 3147 { 3148 (void) unused; 3149 lwb_t *lwb = vbuf; 3150 mutex_destroy(&lwb->lwb_vdev_lock); 3151 avl_destroy(&lwb->lwb_vdev_tree); 3152 list_destroy(&lwb->lwb_waiters); 3153 list_destroy(&lwb->lwb_itxs); 3154 } 3155 3156 void 3157 zil_init(void) 3158 { 3159 zil_lwb_cache = kmem_cache_create("zil_lwb_cache", 3160 sizeof (lwb_t), 0, zil_lwb_cons, zil_lwb_dest, NULL, NULL, NULL, 0); 3161 3162 zil_zcw_cache = kmem_cache_create("zil_zcw_cache", 3163 sizeof (zil_commit_waiter_t), 0, NULL, NULL, NULL, NULL, NULL, 0); 3164 3165 zil_ksp = kstat_create("zfs", 0, "zil", "misc", 3166 KSTAT_TYPE_NAMED, sizeof (zil_stats) / sizeof (kstat_named_t), 3167 KSTAT_FLAG_VIRTUAL); 3168 3169 if (zil_ksp != NULL) { 3170 zil_ksp->ks_data = &zil_stats; 3171 kstat_install(zil_ksp); 3172 } 3173 } 3174 3175 void 3176 zil_fini(void) 3177 { 3178 kmem_cache_destroy(zil_zcw_cache); 3179 kmem_cache_destroy(zil_lwb_cache); 3180 3181 if (zil_ksp != NULL) { 3182 kstat_delete(zil_ksp); 3183 zil_ksp = NULL; 3184 } 3185 } 3186 3187 void 3188 zil_set_sync(zilog_t *zilog, uint64_t sync) 3189 { 3190 zilog->zl_sync = sync; 3191 } 3192 3193 void 3194 zil_set_logbias(zilog_t *zilog, uint64_t logbias) 3195 { 3196 zilog->zl_logbias = logbias; 3197 } 3198 3199 zilog_t * 3200 zil_alloc(objset_t *os, zil_header_t *zh_phys) 3201 { 3202 zilog_t *zilog; 3203 3204 zilog = kmem_zalloc(sizeof (zilog_t), KM_SLEEP); 3205 3206 zilog->zl_header = zh_phys; 3207 zilog->zl_os = os; 3208 zilog->zl_spa = dmu_objset_spa(os); 3209 zilog->zl_dmu_pool = dmu_objset_pool(os); 3210 zilog->zl_destroy_txg = TXG_INITIAL - 1; 3211 zilog->zl_logbias = dmu_objset_logbias(os); 3212 zilog->zl_sync = dmu_objset_syncprop(os); 3213 zilog->zl_dirty_max_txg = 0; 3214 zilog->zl_last_lwb_opened = NULL; 3215 zilog->zl_last_lwb_latency = 0; 3216 zilog->zl_max_block_size = zil_maxblocksize; 3217 3218 mutex_init(&zilog->zl_lock, NULL, MUTEX_DEFAULT, NULL); 3219 mutex_init(&zilog->zl_issuer_lock, NULL, MUTEX_DEFAULT, NULL); 3220 3221 for (int i = 0; i < TXG_SIZE; i++) { 3222 mutex_init(&zilog->zl_itxg[i].itxg_lock, NULL, 3223 MUTEX_DEFAULT, NULL); 3224 } 3225 3226 list_create(&zilog->zl_lwb_list, sizeof (lwb_t), 3227 offsetof(lwb_t, lwb_node)); 3228 3229 list_create(&zilog->zl_itx_commit_list, sizeof (itx_t), 3230 offsetof(itx_t, itx_node)); 3231 3232 cv_init(&zilog->zl_cv_suspend, NULL, CV_DEFAULT, NULL); 3233 3234 return (zilog); 3235 } 3236 3237 void 3238 zil_free(zilog_t *zilog) 3239 { 3240 int i; 3241 3242 zilog->zl_stop_sync = 1; 3243 3244 ASSERT0(zilog->zl_suspend); 3245 ASSERT0(zilog->zl_suspending); 3246 3247 ASSERT(list_is_empty(&zilog->zl_lwb_list)); 3248 list_destroy(&zilog->zl_lwb_list); 3249 3250 ASSERT(list_is_empty(&zilog->zl_itx_commit_list)); 3251 list_destroy(&zilog->zl_itx_commit_list); 3252 3253 for (i = 0; i < TXG_SIZE; i++) { 3254 /* 3255 * It's possible for an itx to be generated that doesn't dirty 3256 * a txg (e.g. ztest TX_TRUNCATE). So there's no zil_clean() 3257 * callback to remove the entry. We remove those here. 3258 * 3259 * Also free up the ziltest itxs. 3260 */ 3261 if (zilog->zl_itxg[i].itxg_itxs) 3262 zil_itxg_clean(zilog->zl_itxg[i].itxg_itxs); 3263 mutex_destroy(&zilog->zl_itxg[i].itxg_lock); 3264 } 3265 3266 mutex_destroy(&zilog->zl_issuer_lock); 3267 mutex_destroy(&zilog->zl_lock); 3268 3269 cv_destroy(&zilog->zl_cv_suspend); 3270 3271 kmem_free(zilog, sizeof (zilog_t)); 3272 } 3273 3274 /* 3275 * Open an intent log. 3276 */ 3277 zilog_t * 3278 zil_open(objset_t *os, zil_get_data_t *get_data) 3279 { 3280 zilog_t *zilog = dmu_objset_zil(os); 3281 3282 ASSERT3P(zilog->zl_get_data, ==, NULL); 3283 ASSERT3P(zilog->zl_last_lwb_opened, ==, NULL); 3284 ASSERT(list_is_empty(&zilog->zl_lwb_list)); 3285 3286 zilog->zl_get_data = get_data; 3287 3288 return (zilog); 3289 } 3290 3291 /* 3292 * Close an intent log. 3293 */ 3294 void 3295 zil_close(zilog_t *zilog) 3296 { 3297 lwb_t *lwb; 3298 uint64_t txg; 3299 3300 if (!dmu_objset_is_snapshot(zilog->zl_os)) { 3301 zil_commit(zilog, 0); 3302 } else { 3303 ASSERT3P(list_tail(&zilog->zl_lwb_list), ==, NULL); 3304 ASSERT0(zilog->zl_dirty_max_txg); 3305 ASSERT3B(zilog_is_dirty(zilog), ==, B_FALSE); 3306 } 3307 3308 mutex_enter(&zilog->zl_lock); 3309 lwb = list_tail(&zilog->zl_lwb_list); 3310 if (lwb == NULL) 3311 txg = zilog->zl_dirty_max_txg; 3312 else 3313 txg = MAX(zilog->zl_dirty_max_txg, lwb->lwb_max_txg); 3314 mutex_exit(&zilog->zl_lock); 3315 3316 /* 3317 * We need to use txg_wait_synced() to wait long enough for the 3318 * ZIL to be clean, and to wait for all pending lwbs to be 3319 * written out. 3320 */ 3321 if (txg != 0) 3322 txg_wait_synced(zilog->zl_dmu_pool, txg); 3323 3324 if (zilog_is_dirty(zilog)) 3325 zfs_dbgmsg("zil (%px) is dirty, txg %llu", zilog, 3326 (u_longlong_t)txg); 3327 if (txg < spa_freeze_txg(zilog->zl_spa)) 3328 VERIFY(!zilog_is_dirty(zilog)); 3329 3330 zilog->zl_get_data = NULL; 3331 3332 /* 3333 * We should have only one lwb left on the list; remove it now. 3334 */ 3335 mutex_enter(&zilog->zl_lock); 3336 lwb = list_head(&zilog->zl_lwb_list); 3337 if (lwb != NULL) { 3338 ASSERT3P(lwb, ==, list_tail(&zilog->zl_lwb_list)); 3339 ASSERT3S(lwb->lwb_state, !=, LWB_STATE_ISSUED); 3340 3341 if (lwb->lwb_fastwrite) 3342 metaslab_fastwrite_unmark(zilog->zl_spa, &lwb->lwb_blk); 3343 3344 list_remove(&zilog->zl_lwb_list, lwb); 3345 zio_buf_free(lwb->lwb_buf, lwb->lwb_sz); 3346 zil_free_lwb(zilog, lwb); 3347 } 3348 mutex_exit(&zilog->zl_lock); 3349 } 3350 3351 static char *suspend_tag = "zil suspending"; 3352 3353 /* 3354 * Suspend an intent log. While in suspended mode, we still honor 3355 * synchronous semantics, but we rely on txg_wait_synced() to do it. 3356 * On old version pools, we suspend the log briefly when taking a 3357 * snapshot so that it will have an empty intent log. 3358 * 3359 * Long holds are not really intended to be used the way we do here -- 3360 * held for such a short time. A concurrent caller of dsl_dataset_long_held() 3361 * could fail. Therefore we take pains to only put a long hold if it is 3362 * actually necessary. Fortunately, it will only be necessary if the 3363 * objset is currently mounted (or the ZVOL equivalent). In that case it 3364 * will already have a long hold, so we are not really making things any worse. 3365 * 3366 * Ideally, we would locate the existing long-holder (i.e. the zfsvfs_t or 3367 * zvol_state_t), and use their mechanism to prevent their hold from being 3368 * dropped (e.g. VFS_HOLD()). However, that would be even more pain for 3369 * very little gain. 3370 * 3371 * if cookiep == NULL, this does both the suspend & resume. 3372 * Otherwise, it returns with the dataset "long held", and the cookie 3373 * should be passed into zil_resume(). 3374 */ 3375 int 3376 zil_suspend(const char *osname, void **cookiep) 3377 { 3378 objset_t *os; 3379 zilog_t *zilog; 3380 const zil_header_t *zh; 3381 int error; 3382 3383 error = dmu_objset_hold(osname, suspend_tag, &os); 3384 if (error != 0) 3385 return (error); 3386 zilog = dmu_objset_zil(os); 3387 3388 mutex_enter(&zilog->zl_lock); 3389 zh = zilog->zl_header; 3390 3391 if (zh->zh_flags & ZIL_REPLAY_NEEDED) { /* unplayed log */ 3392 mutex_exit(&zilog->zl_lock); 3393 dmu_objset_rele(os, suspend_tag); 3394 return (SET_ERROR(EBUSY)); 3395 } 3396 3397 /* 3398 * Don't put a long hold in the cases where we can avoid it. This 3399 * is when there is no cookie so we are doing a suspend & resume 3400 * (i.e. called from zil_vdev_offline()), and there's nothing to do 3401 * for the suspend because it's already suspended, or there's no ZIL. 3402 */ 3403 if (cookiep == NULL && !zilog->zl_suspending && 3404 (zilog->zl_suspend > 0 || BP_IS_HOLE(&zh->zh_log))) { 3405 mutex_exit(&zilog->zl_lock); 3406 dmu_objset_rele(os, suspend_tag); 3407 return (0); 3408 } 3409 3410 dsl_dataset_long_hold(dmu_objset_ds(os), suspend_tag); 3411 dsl_pool_rele(dmu_objset_pool(os), suspend_tag); 3412 3413 zilog->zl_suspend++; 3414 3415 if (zilog->zl_suspend > 1) { 3416 /* 3417 * Someone else is already suspending it. 3418 * Just wait for them to finish. 3419 */ 3420 3421 while (zilog->zl_suspending) 3422 cv_wait(&zilog->zl_cv_suspend, &zilog->zl_lock); 3423 mutex_exit(&zilog->zl_lock); 3424 3425 if (cookiep == NULL) 3426 zil_resume(os); 3427 else 3428 *cookiep = os; 3429 return (0); 3430 } 3431 3432 /* 3433 * If there is no pointer to an on-disk block, this ZIL must not 3434 * be active (e.g. filesystem not mounted), so there's nothing 3435 * to clean up. 3436 */ 3437 if (BP_IS_HOLE(&zh->zh_log)) { 3438 ASSERT(cookiep != NULL); /* fast path already handled */ 3439 3440 *cookiep = os; 3441 mutex_exit(&zilog->zl_lock); 3442 return (0); 3443 } 3444 3445 /* 3446 * The ZIL has work to do. Ensure that the associated encryption 3447 * key will remain mapped while we are committing the log by 3448 * grabbing a reference to it. If the key isn't loaded we have no 3449 * choice but to return an error until the wrapping key is loaded. 3450 */ 3451 if (os->os_encrypted && 3452 dsl_dataset_create_key_mapping(dmu_objset_ds(os)) != 0) { 3453 zilog->zl_suspend--; 3454 mutex_exit(&zilog->zl_lock); 3455 dsl_dataset_long_rele(dmu_objset_ds(os), suspend_tag); 3456 dsl_dataset_rele(dmu_objset_ds(os), suspend_tag); 3457 return (SET_ERROR(EACCES)); 3458 } 3459 3460 zilog->zl_suspending = B_TRUE; 3461 mutex_exit(&zilog->zl_lock); 3462 3463 /* 3464 * We need to use zil_commit_impl to ensure we wait for all 3465 * LWB_STATE_OPENED and LWB_STATE_ISSUED lwbs to be committed 3466 * to disk before proceeding. If we used zil_commit instead, it 3467 * would just call txg_wait_synced(), because zl_suspend is set. 3468 * txg_wait_synced() doesn't wait for these lwb's to be 3469 * LWB_STATE_FLUSH_DONE before returning. 3470 */ 3471 zil_commit_impl(zilog, 0); 3472 3473 /* 3474 * Now that we've ensured all lwb's are LWB_STATE_FLUSH_DONE, we 3475 * use txg_wait_synced() to ensure the data from the zilog has 3476 * migrated to the main pool before calling zil_destroy(). 3477 */ 3478 txg_wait_synced(zilog->zl_dmu_pool, 0); 3479 3480 zil_destroy(zilog, B_FALSE); 3481 3482 mutex_enter(&zilog->zl_lock); 3483 zilog->zl_suspending = B_FALSE; 3484 cv_broadcast(&zilog->zl_cv_suspend); 3485 mutex_exit(&zilog->zl_lock); 3486 3487 if (os->os_encrypted) 3488 dsl_dataset_remove_key_mapping(dmu_objset_ds(os)); 3489 3490 if (cookiep == NULL) 3491 zil_resume(os); 3492 else 3493 *cookiep = os; 3494 return (0); 3495 } 3496 3497 void 3498 zil_resume(void *cookie) 3499 { 3500 objset_t *os = cookie; 3501 zilog_t *zilog = dmu_objset_zil(os); 3502 3503 mutex_enter(&zilog->zl_lock); 3504 ASSERT(zilog->zl_suspend != 0); 3505 zilog->zl_suspend--; 3506 mutex_exit(&zilog->zl_lock); 3507 dsl_dataset_long_rele(dmu_objset_ds(os), suspend_tag); 3508 dsl_dataset_rele(dmu_objset_ds(os), suspend_tag); 3509 } 3510 3511 typedef struct zil_replay_arg { 3512 zil_replay_func_t *const *zr_replay; 3513 void *zr_arg; 3514 boolean_t zr_byteswap; 3515 char *zr_lr; 3516 } zil_replay_arg_t; 3517 3518 static int 3519 zil_replay_error(zilog_t *zilog, const lr_t *lr, int error) 3520 { 3521 char name[ZFS_MAX_DATASET_NAME_LEN]; 3522 3523 zilog->zl_replaying_seq--; /* didn't actually replay this one */ 3524 3525 dmu_objset_name(zilog->zl_os, name); 3526 3527 cmn_err(CE_WARN, "ZFS replay transaction error %d, " 3528 "dataset %s, seq 0x%llx, txtype %llu %s\n", error, name, 3529 (u_longlong_t)lr->lrc_seq, 3530 (u_longlong_t)(lr->lrc_txtype & ~TX_CI), 3531 (lr->lrc_txtype & TX_CI) ? "CI" : ""); 3532 3533 return (error); 3534 } 3535 3536 static int 3537 zil_replay_log_record(zilog_t *zilog, const lr_t *lr, void *zra, 3538 uint64_t claim_txg) 3539 { 3540 zil_replay_arg_t *zr = zra; 3541 const zil_header_t *zh = zilog->zl_header; 3542 uint64_t reclen = lr->lrc_reclen; 3543 uint64_t txtype = lr->lrc_txtype; 3544 int error = 0; 3545 3546 zilog->zl_replaying_seq = lr->lrc_seq; 3547 3548 if (lr->lrc_seq <= zh->zh_replay_seq) /* already replayed */ 3549 return (0); 3550 3551 if (lr->lrc_txg < claim_txg) /* already committed */ 3552 return (0); 3553 3554 /* Strip case-insensitive bit, still present in log record */ 3555 txtype &= ~TX_CI; 3556 3557 if (txtype == 0 || txtype >= TX_MAX_TYPE) 3558 return (zil_replay_error(zilog, lr, EINVAL)); 3559 3560 /* 3561 * If this record type can be logged out of order, the object 3562 * (lr_foid) may no longer exist. That's legitimate, not an error. 3563 */ 3564 if (TX_OOO(txtype)) { 3565 error = dmu_object_info(zilog->zl_os, 3566 LR_FOID_GET_OBJ(((lr_ooo_t *)lr)->lr_foid), NULL); 3567 if (error == ENOENT || error == EEXIST) 3568 return (0); 3569 } 3570 3571 /* 3572 * Make a copy of the data so we can revise and extend it. 3573 */ 3574 bcopy(lr, zr->zr_lr, reclen); 3575 3576 /* 3577 * If this is a TX_WRITE with a blkptr, suck in the data. 3578 */ 3579 if (txtype == TX_WRITE && reclen == sizeof (lr_write_t)) { 3580 error = zil_read_log_data(zilog, (lr_write_t *)lr, 3581 zr->zr_lr + reclen); 3582 if (error != 0) 3583 return (zil_replay_error(zilog, lr, error)); 3584 } 3585 3586 /* 3587 * The log block containing this lr may have been byteswapped 3588 * so that we can easily examine common fields like lrc_txtype. 3589 * However, the log is a mix of different record types, and only the 3590 * replay vectors know how to byteswap their records. Therefore, if 3591 * the lr was byteswapped, undo it before invoking the replay vector. 3592 */ 3593 if (zr->zr_byteswap) 3594 byteswap_uint64_array(zr->zr_lr, reclen); 3595 3596 /* 3597 * We must now do two things atomically: replay this log record, 3598 * and update the log header sequence number to reflect the fact that 3599 * we did so. At the end of each replay function the sequence number 3600 * is updated if we are in replay mode. 3601 */ 3602 error = zr->zr_replay[txtype](zr->zr_arg, zr->zr_lr, zr->zr_byteswap); 3603 if (error != 0) { 3604 /* 3605 * The DMU's dnode layer doesn't see removes until the txg 3606 * commits, so a subsequent claim can spuriously fail with 3607 * EEXIST. So if we receive any error we try syncing out 3608 * any removes then retry the transaction. Note that we 3609 * specify B_FALSE for byteswap now, so we don't do it twice. 3610 */ 3611 txg_wait_synced(spa_get_dsl(zilog->zl_spa), 0); 3612 error = zr->zr_replay[txtype](zr->zr_arg, zr->zr_lr, B_FALSE); 3613 if (error != 0) 3614 return (zil_replay_error(zilog, lr, error)); 3615 } 3616 return (0); 3617 } 3618 3619 static int 3620 zil_incr_blks(zilog_t *zilog, const blkptr_t *bp, void *arg, uint64_t claim_txg) 3621 { 3622 (void) bp, (void) arg, (void) claim_txg; 3623 3624 zilog->zl_replay_blks++; 3625 3626 return (0); 3627 } 3628 3629 /* 3630 * If this dataset has a non-empty intent log, replay it and destroy it. 3631 */ 3632 void 3633 zil_replay(objset_t *os, void *arg, 3634 zil_replay_func_t *const replay_func[TX_MAX_TYPE]) 3635 { 3636 zilog_t *zilog = dmu_objset_zil(os); 3637 const zil_header_t *zh = zilog->zl_header; 3638 zil_replay_arg_t zr; 3639 3640 if ((zh->zh_flags & ZIL_REPLAY_NEEDED) == 0) { 3641 zil_destroy(zilog, B_TRUE); 3642 return; 3643 } 3644 3645 zr.zr_replay = replay_func; 3646 zr.zr_arg = arg; 3647 zr.zr_byteswap = BP_SHOULD_BYTESWAP(&zh->zh_log); 3648 zr.zr_lr = vmem_alloc(2 * SPA_MAXBLOCKSIZE, KM_SLEEP); 3649 3650 /* 3651 * Wait for in-progress removes to sync before starting replay. 3652 */ 3653 txg_wait_synced(zilog->zl_dmu_pool, 0); 3654 3655 zilog->zl_replay = B_TRUE; 3656 zilog->zl_replay_time = ddi_get_lbolt(); 3657 ASSERT(zilog->zl_replay_blks == 0); 3658 (void) zil_parse(zilog, zil_incr_blks, zil_replay_log_record, &zr, 3659 zh->zh_claim_txg, B_TRUE); 3660 vmem_free(zr.zr_lr, 2 * SPA_MAXBLOCKSIZE); 3661 3662 zil_destroy(zilog, B_FALSE); 3663 txg_wait_synced(zilog->zl_dmu_pool, zilog->zl_destroy_txg); 3664 zilog->zl_replay = B_FALSE; 3665 } 3666 3667 boolean_t 3668 zil_replaying(zilog_t *zilog, dmu_tx_t *tx) 3669 { 3670 if (zilog->zl_sync == ZFS_SYNC_DISABLED) 3671 return (B_TRUE); 3672 3673 if (zilog->zl_replay) { 3674 dsl_dataset_dirty(dmu_objset_ds(zilog->zl_os), tx); 3675 zilog->zl_replayed_seq[dmu_tx_get_txg(tx) & TXG_MASK] = 3676 zilog->zl_replaying_seq; 3677 return (B_TRUE); 3678 } 3679 3680 return (B_FALSE); 3681 } 3682 3683 int 3684 zil_reset(const char *osname, void *arg) 3685 { 3686 (void) arg; 3687 3688 int error = zil_suspend(osname, NULL); 3689 /* EACCES means crypto key not loaded */ 3690 if ((error == EACCES) || (error == EBUSY)) 3691 return (SET_ERROR(error)); 3692 if (error != 0) 3693 return (SET_ERROR(EEXIST)); 3694 return (0); 3695 } 3696 3697 EXPORT_SYMBOL(zil_alloc); 3698 EXPORT_SYMBOL(zil_free); 3699 EXPORT_SYMBOL(zil_open); 3700 EXPORT_SYMBOL(zil_close); 3701 EXPORT_SYMBOL(zil_replay); 3702 EXPORT_SYMBOL(zil_replaying); 3703 EXPORT_SYMBOL(zil_destroy); 3704 EXPORT_SYMBOL(zil_destroy_sync); 3705 EXPORT_SYMBOL(zil_itx_create); 3706 EXPORT_SYMBOL(zil_itx_destroy); 3707 EXPORT_SYMBOL(zil_itx_assign); 3708 EXPORT_SYMBOL(zil_commit); 3709 EXPORT_SYMBOL(zil_claim); 3710 EXPORT_SYMBOL(zil_check_log_chain); 3711 EXPORT_SYMBOL(zil_sync); 3712 EXPORT_SYMBOL(zil_clean); 3713 EXPORT_SYMBOL(zil_suspend); 3714 EXPORT_SYMBOL(zil_resume); 3715 EXPORT_SYMBOL(zil_lwb_add_block); 3716 EXPORT_SYMBOL(zil_bp_tree_add); 3717 EXPORT_SYMBOL(zil_set_sync); 3718 EXPORT_SYMBOL(zil_set_logbias); 3719 3720 /* BEGIN CSTYLED */ 3721 ZFS_MODULE_PARAM(zfs, zfs_, commit_timeout_pct, INT, ZMOD_RW, 3722 "ZIL block open timeout percentage"); 3723 3724 ZFS_MODULE_PARAM(zfs_zil, zil_, replay_disable, INT, ZMOD_RW, 3725 "Disable intent logging replay"); 3726 3727 ZFS_MODULE_PARAM(zfs_zil, zil_, nocacheflush, INT, ZMOD_RW, 3728 "Disable ZIL cache flushes"); 3729 3730 ZFS_MODULE_PARAM(zfs_zil, zil_, slog_bulk, ULONG, ZMOD_RW, 3731 "Limit in bytes slog sync writes per commit"); 3732 3733 ZFS_MODULE_PARAM(zfs_zil, zil_, maxblocksize, INT, ZMOD_RW, 3734 "Limit in bytes of ZIL log block size"); 3735 /* END CSTYLED */ 3736