zil.c revision 332547
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, 2017 by Delphix. All rights reserved. 24 * Copyright (c) 2014 Integros [integros.com] 25 */ 26 27/* Portions Copyright 2010 Robert Milkowski */ 28 29#include <sys/zfs_context.h> 30#include <sys/spa.h> 31#include <sys/spa_impl.h> 32#include <sys/dmu.h> 33#include <sys/zap.h> 34#include <sys/arc.h> 35#include <sys/stat.h> 36#include <sys/resource.h> 37#include <sys/zil.h> 38#include <sys/zil_impl.h> 39#include <sys/dsl_dataset.h> 40#include <sys/vdev_impl.h> 41#include <sys/dmu_tx.h> 42#include <sys/dsl_pool.h> 43#include <sys/abd.h> 44 45/* 46 * The ZFS Intent Log (ZIL) saves "transaction records" (itxs) of system 47 * calls that change the file system. Each itx has enough information to 48 * be able to replay them after a system crash, power loss, or 49 * equivalent failure mode. These are stored in memory until either: 50 * 51 * 1. they are committed to the pool by the DMU transaction group 52 * (txg), at which point they can be discarded; or 53 * 2. they are committed to the on-disk ZIL for the dataset being 54 * modified (e.g. due to an fsync, O_DSYNC, or other synchronous 55 * requirement). 56 * 57 * In the event of a crash or power loss, the itxs contained by each 58 * dataset's on-disk ZIL will be replayed when that dataset is first 59 * instantianted (e.g. if the dataset is a normal fileystem, when it is 60 * first mounted). 61 * 62 * As hinted at above, there is one ZIL per dataset (both the in-memory 63 * representation, and the on-disk representation). The on-disk format 64 * consists of 3 parts: 65 * 66 * - a single, per-dataset, ZIL header; which points to a chain of 67 * - zero or more ZIL blocks; each of which contains 68 * - zero or more ZIL records 69 * 70 * A ZIL record holds the information necessary to replay a single 71 * system call transaction. A ZIL block can hold many ZIL records, and 72 * the blocks are chained together, similarly to a singly linked list. 73 * 74 * Each ZIL block contains a block pointer (blkptr_t) to the next ZIL 75 * block in the chain, and the ZIL header points to the first block in 76 * the chain. 77 * 78 * Note, there is not a fixed place in the pool to hold these ZIL 79 * blocks; they are dynamically allocated and freed as needed from the 80 * blocks available on the pool, though they can be preferentially 81 * allocated from a dedicated "log" vdev. 82 */ 83 84/* 85 * This controls the amount of time that a ZIL block (lwb) will remain 86 * "open" when it isn't "full", and it has a thread waiting for it to be 87 * committed to stable storage. Please refer to the zil_commit_waiter() 88 * function (and the comments within it) for more details. 89 */ 90int zfs_commit_timeout_pct = 5; 91 92/* 93 * Disable intent logging replay. This global ZIL switch affects all pools. 94 */ 95int zil_replay_disable = 0; 96SYSCTL_DECL(_vfs_zfs); 97SYSCTL_INT(_vfs_zfs, OID_AUTO, zil_replay_disable, CTLFLAG_RWTUN, 98 &zil_replay_disable, 0, "Disable intent logging replay"); 99 100/* 101 * Tunable parameter for debugging or performance analysis. Setting 102 * zfs_nocacheflush will cause corruption on power loss if a volatile 103 * out-of-order write cache is enabled. 104 */ 105boolean_t zfs_nocacheflush = B_FALSE; 106SYSCTL_INT(_vfs_zfs, OID_AUTO, cache_flush_disable, CTLFLAG_RDTUN, 107 &zfs_nocacheflush, 0, "Disable cache flush"); 108boolean_t zfs_trim_enabled = B_TRUE; 109SYSCTL_DECL(_vfs_zfs_trim); 110SYSCTL_INT(_vfs_zfs_trim, OID_AUTO, enabled, CTLFLAG_RDTUN, &zfs_trim_enabled, 0, 111 "Enable ZFS TRIM"); 112 113/* 114 * Limit SLOG write size per commit executed with synchronous priority. 115 * Any writes above that will be executed with lower (asynchronous) priority 116 * to limit potential SLOG device abuse by single active ZIL writer. 117 */ 118uint64_t zil_slog_bulk = 768 * 1024; 119SYSCTL_QUAD(_vfs_zfs, OID_AUTO, zil_slog_bulk, CTLFLAG_RWTUN, 120 &zil_slog_bulk, 0, "Maximal SLOG commit size with sync priority"); 121 122static kmem_cache_t *zil_lwb_cache; 123static kmem_cache_t *zil_zcw_cache; 124 125#define LWB_EMPTY(lwb) ((BP_GET_LSIZE(&lwb->lwb_blk) - \ 126 sizeof (zil_chain_t)) == (lwb->lwb_sz - lwb->lwb_nused)) 127 128static int 129zil_bp_compare(const void *x1, const void *x2) 130{ 131 const dva_t *dva1 = &((zil_bp_node_t *)x1)->zn_dva; 132 const dva_t *dva2 = &((zil_bp_node_t *)x2)->zn_dva; 133 134 if (DVA_GET_VDEV(dva1) < DVA_GET_VDEV(dva2)) 135 return (-1); 136 if (DVA_GET_VDEV(dva1) > DVA_GET_VDEV(dva2)) 137 return (1); 138 139 if (DVA_GET_OFFSET(dva1) < DVA_GET_OFFSET(dva2)) 140 return (-1); 141 if (DVA_GET_OFFSET(dva1) > DVA_GET_OFFSET(dva2)) 142 return (1); 143 144 return (0); 145} 146 147static void 148zil_bp_tree_init(zilog_t *zilog) 149{ 150 avl_create(&zilog->zl_bp_tree, zil_bp_compare, 151 sizeof (zil_bp_node_t), offsetof(zil_bp_node_t, zn_node)); 152} 153 154static void 155zil_bp_tree_fini(zilog_t *zilog) 156{ 157 avl_tree_t *t = &zilog->zl_bp_tree; 158 zil_bp_node_t *zn; 159 void *cookie = NULL; 160 161 while ((zn = avl_destroy_nodes(t, &cookie)) != NULL) 162 kmem_free(zn, sizeof (zil_bp_node_t)); 163 164 avl_destroy(t); 165} 166 167int 168zil_bp_tree_add(zilog_t *zilog, const blkptr_t *bp) 169{ 170 avl_tree_t *t = &zilog->zl_bp_tree; 171 const dva_t *dva; 172 zil_bp_node_t *zn; 173 avl_index_t where; 174 175 if (BP_IS_EMBEDDED(bp)) 176 return (0); 177 178 dva = BP_IDENTITY(bp); 179 180 if (avl_find(t, dva, &where) != NULL) 181 return (SET_ERROR(EEXIST)); 182 183 zn = kmem_alloc(sizeof (zil_bp_node_t), KM_SLEEP); 184 zn->zn_dva = *dva; 185 avl_insert(t, zn, where); 186 187 return (0); 188} 189 190static zil_header_t * 191zil_header_in_syncing_context(zilog_t *zilog) 192{ 193 return ((zil_header_t *)zilog->zl_header); 194} 195 196static void 197zil_init_log_chain(zilog_t *zilog, blkptr_t *bp) 198{ 199 zio_cksum_t *zc = &bp->blk_cksum; 200 201 zc->zc_word[ZIL_ZC_GUID_0] = spa_get_random(-1ULL); 202 zc->zc_word[ZIL_ZC_GUID_1] = spa_get_random(-1ULL); 203 zc->zc_word[ZIL_ZC_OBJSET] = dmu_objset_id(zilog->zl_os); 204 zc->zc_word[ZIL_ZC_SEQ] = 1ULL; 205} 206 207/* 208 * Read a log block and make sure it's valid. 209 */ 210static int 211zil_read_log_block(zilog_t *zilog, const blkptr_t *bp, blkptr_t *nbp, void *dst, 212 char **end) 213{ 214 enum zio_flag zio_flags = ZIO_FLAG_CANFAIL; 215 arc_flags_t aflags = ARC_FLAG_WAIT; 216 arc_buf_t *abuf = NULL; 217 zbookmark_phys_t zb; 218 int error; 219 220 if (zilog->zl_header->zh_claim_txg == 0) 221 zio_flags |= ZIO_FLAG_SPECULATIVE | ZIO_FLAG_SCRUB; 222 223 if (!(zilog->zl_header->zh_flags & ZIL_CLAIM_LR_SEQ_VALID)) 224 zio_flags |= ZIO_FLAG_SPECULATIVE; 225 226 SET_BOOKMARK(&zb, bp->blk_cksum.zc_word[ZIL_ZC_OBJSET], 227 ZB_ZIL_OBJECT, ZB_ZIL_LEVEL, bp->blk_cksum.zc_word[ZIL_ZC_SEQ]); 228 229 error = arc_read(NULL, zilog->zl_spa, bp, arc_getbuf_func, &abuf, 230 ZIO_PRIORITY_SYNC_READ, zio_flags, &aflags, &zb); 231 232 if (error == 0) { 233 zio_cksum_t cksum = bp->blk_cksum; 234 235 /* 236 * Validate the checksummed log block. 237 * 238 * Sequence numbers should be... sequential. The checksum 239 * verifier for the next block should be bp's checksum plus 1. 240 * 241 * Also check the log chain linkage and size used. 242 */ 243 cksum.zc_word[ZIL_ZC_SEQ]++; 244 245 if (BP_GET_CHECKSUM(bp) == ZIO_CHECKSUM_ZILOG2) { 246 zil_chain_t *zilc = abuf->b_data; 247 char *lr = (char *)(zilc + 1); 248 uint64_t len = zilc->zc_nused - sizeof (zil_chain_t); 249 250 if (bcmp(&cksum, &zilc->zc_next_blk.blk_cksum, 251 sizeof (cksum)) || BP_IS_HOLE(&zilc->zc_next_blk)) { 252 error = SET_ERROR(ECKSUM); 253 } else { 254 ASSERT3U(len, <=, SPA_OLD_MAXBLOCKSIZE); 255 bcopy(lr, dst, len); 256 *end = (char *)dst + len; 257 *nbp = zilc->zc_next_blk; 258 } 259 } else { 260 char *lr = abuf->b_data; 261 uint64_t size = BP_GET_LSIZE(bp); 262 zil_chain_t *zilc = (zil_chain_t *)(lr + size) - 1; 263 264 if (bcmp(&cksum, &zilc->zc_next_blk.blk_cksum, 265 sizeof (cksum)) || BP_IS_HOLE(&zilc->zc_next_blk) || 266 (zilc->zc_nused > (size - sizeof (*zilc)))) { 267 error = SET_ERROR(ECKSUM); 268 } else { 269 ASSERT3U(zilc->zc_nused, <=, 270 SPA_OLD_MAXBLOCKSIZE); 271 bcopy(lr, dst, zilc->zc_nused); 272 *end = (char *)dst + zilc->zc_nused; 273 *nbp = zilc->zc_next_blk; 274 } 275 } 276 277 arc_buf_destroy(abuf, &abuf); 278 } 279 280 return (error); 281} 282 283/* 284 * Read a TX_WRITE log data block. 285 */ 286static int 287zil_read_log_data(zilog_t *zilog, const lr_write_t *lr, void *wbuf) 288{ 289 enum zio_flag zio_flags = ZIO_FLAG_CANFAIL; 290 const blkptr_t *bp = &lr->lr_blkptr; 291 arc_flags_t aflags = ARC_FLAG_WAIT; 292 arc_buf_t *abuf = NULL; 293 zbookmark_phys_t zb; 294 int error; 295 296 if (BP_IS_HOLE(bp)) { 297 if (wbuf != NULL) 298 bzero(wbuf, MAX(BP_GET_LSIZE(bp), lr->lr_length)); 299 return (0); 300 } 301 302 if (zilog->zl_header->zh_claim_txg == 0) 303 zio_flags |= ZIO_FLAG_SPECULATIVE | ZIO_FLAG_SCRUB; 304 305 SET_BOOKMARK(&zb, dmu_objset_id(zilog->zl_os), lr->lr_foid, 306 ZB_ZIL_LEVEL, lr->lr_offset / BP_GET_LSIZE(bp)); 307 308 error = arc_read(NULL, zilog->zl_spa, bp, arc_getbuf_func, &abuf, 309 ZIO_PRIORITY_SYNC_READ, zio_flags, &aflags, &zb); 310 311 if (error == 0) { 312 if (wbuf != NULL) 313 bcopy(abuf->b_data, wbuf, arc_buf_size(abuf)); 314 arc_buf_destroy(abuf, &abuf); 315 } 316 317 return (error); 318} 319 320/* 321 * Parse the intent log, and call parse_func for each valid record within. 322 */ 323int 324zil_parse(zilog_t *zilog, zil_parse_blk_func_t *parse_blk_func, 325 zil_parse_lr_func_t *parse_lr_func, void *arg, uint64_t txg) 326{ 327 const zil_header_t *zh = zilog->zl_header; 328 boolean_t claimed = !!zh->zh_claim_txg; 329 uint64_t claim_blk_seq = claimed ? zh->zh_claim_blk_seq : UINT64_MAX; 330 uint64_t claim_lr_seq = claimed ? zh->zh_claim_lr_seq : UINT64_MAX; 331 uint64_t max_blk_seq = 0; 332 uint64_t max_lr_seq = 0; 333 uint64_t blk_count = 0; 334 uint64_t lr_count = 0; 335 blkptr_t blk, next_blk; 336 char *lrbuf, *lrp; 337 int error = 0; 338 339 /* 340 * Old logs didn't record the maximum zh_claim_lr_seq. 341 */ 342 if (!(zh->zh_flags & ZIL_CLAIM_LR_SEQ_VALID)) 343 claim_lr_seq = UINT64_MAX; 344 345 /* 346 * Starting at the block pointed to by zh_log we read the log chain. 347 * For each block in the chain we strongly check that block to 348 * ensure its validity. We stop when an invalid block is found. 349 * For each block pointer in the chain we call parse_blk_func(). 350 * For each record in each valid block we call parse_lr_func(). 351 * If the log has been claimed, stop if we encounter a sequence 352 * number greater than the highest claimed sequence number. 353 */ 354 lrbuf = zio_buf_alloc(SPA_OLD_MAXBLOCKSIZE); 355 zil_bp_tree_init(zilog); 356 357 for (blk = zh->zh_log; !BP_IS_HOLE(&blk); blk = next_blk) { 358 uint64_t blk_seq = blk.blk_cksum.zc_word[ZIL_ZC_SEQ]; 359 int reclen; 360 char *end; 361 362 if (blk_seq > claim_blk_seq) 363 break; 364 if ((error = parse_blk_func(zilog, &blk, arg, txg)) != 0) 365 break; 366 ASSERT3U(max_blk_seq, <, blk_seq); 367 max_blk_seq = blk_seq; 368 blk_count++; 369 370 if (max_lr_seq == claim_lr_seq && max_blk_seq == claim_blk_seq) 371 break; 372 373 error = zil_read_log_block(zilog, &blk, &next_blk, lrbuf, &end); 374 if (error != 0) 375 break; 376 377 for (lrp = lrbuf; lrp < end; lrp += reclen) { 378 lr_t *lr = (lr_t *)lrp; 379 reclen = lr->lrc_reclen; 380 ASSERT3U(reclen, >=, sizeof (lr_t)); 381 if (lr->lrc_seq > claim_lr_seq) 382 goto done; 383 if ((error = parse_lr_func(zilog, lr, arg, txg)) != 0) 384 goto done; 385 ASSERT3U(max_lr_seq, <, lr->lrc_seq); 386 max_lr_seq = lr->lrc_seq; 387 lr_count++; 388 } 389 } 390done: 391 zilog->zl_parse_error = error; 392 zilog->zl_parse_blk_seq = max_blk_seq; 393 zilog->zl_parse_lr_seq = max_lr_seq; 394 zilog->zl_parse_blk_count = blk_count; 395 zilog->zl_parse_lr_count = lr_count; 396 397 ASSERT(!claimed || !(zh->zh_flags & ZIL_CLAIM_LR_SEQ_VALID) || 398 (max_blk_seq == claim_blk_seq && max_lr_seq == claim_lr_seq)); 399 400 zil_bp_tree_fini(zilog); 401 zio_buf_free(lrbuf, SPA_OLD_MAXBLOCKSIZE); 402 403 return (error); 404} 405 406/* ARGSUSED */ 407static int 408zil_clear_log_block(zilog_t *zilog, blkptr_t *bp, void *tx, uint64_t first_txg) 409{ 410 ASSERT(!BP_IS_HOLE(bp)); 411 412 /* 413 * As we call this function from the context of a rewind to a 414 * checkpoint, each ZIL block whose txg is later than the txg 415 * that we rewind to is invalid. Thus, we return -1 so 416 * zil_parse() doesn't attempt to read it. 417 */ 418 if (bp->blk_birth >= first_txg) 419 return (-1); 420 421 if (zil_bp_tree_add(zilog, bp) != 0) 422 return (0); 423 424 zio_free(zilog->zl_spa, first_txg, bp); 425 return (0); 426} 427 428/* ARGSUSED */ 429static int 430zil_noop_log_record(zilog_t *zilog, lr_t *lrc, void *tx, uint64_t first_txg) 431{ 432 return (0); 433} 434 435static int 436zil_claim_log_block(zilog_t *zilog, blkptr_t *bp, void *tx, uint64_t first_txg) 437{ 438 /* 439 * Claim log block if not already committed and not already claimed. 440 * If tx == NULL, just verify that the block is claimable. 441 */ 442 if (BP_IS_HOLE(bp) || bp->blk_birth < first_txg || 443 zil_bp_tree_add(zilog, bp) != 0) 444 return (0); 445 446 return (zio_wait(zio_claim(NULL, zilog->zl_spa, 447 tx == NULL ? 0 : first_txg, bp, spa_claim_notify, NULL, 448 ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE | ZIO_FLAG_SCRUB))); 449} 450 451static int 452zil_claim_log_record(zilog_t *zilog, lr_t *lrc, void *tx, uint64_t first_txg) 453{ 454 lr_write_t *lr = (lr_write_t *)lrc; 455 int error; 456 457 if (lrc->lrc_txtype != TX_WRITE) 458 return (0); 459 460 /* 461 * If the block is not readable, don't claim it. This can happen 462 * in normal operation when a log block is written to disk before 463 * some of the dmu_sync() blocks it points to. In this case, the 464 * transaction cannot have been committed to anyone (we would have 465 * waited for all writes to be stable first), so it is semantically 466 * correct to declare this the end of the log. 467 */ 468 if (lr->lr_blkptr.blk_birth >= first_txg && 469 (error = zil_read_log_data(zilog, lr, NULL)) != 0) 470 return (error); 471 return (zil_claim_log_block(zilog, &lr->lr_blkptr, tx, first_txg)); 472} 473 474/* ARGSUSED */ 475static int 476zil_free_log_block(zilog_t *zilog, blkptr_t *bp, void *tx, uint64_t claim_txg) 477{ 478 zio_free(zilog->zl_spa, dmu_tx_get_txg(tx), bp); 479 480 return (0); 481} 482 483static int 484zil_free_log_record(zilog_t *zilog, lr_t *lrc, void *tx, uint64_t claim_txg) 485{ 486 lr_write_t *lr = (lr_write_t *)lrc; 487 blkptr_t *bp = &lr->lr_blkptr; 488 489 /* 490 * If we previously claimed it, we need to free it. 491 */ 492 if (claim_txg != 0 && lrc->lrc_txtype == TX_WRITE && 493 bp->blk_birth >= claim_txg && zil_bp_tree_add(zilog, bp) == 0 && 494 !BP_IS_HOLE(bp)) 495 zio_free(zilog->zl_spa, dmu_tx_get_txg(tx), bp); 496 497 return (0); 498} 499 500static int 501zil_lwb_vdev_compare(const void *x1, const void *x2) 502{ 503 const uint64_t v1 = ((zil_vdev_node_t *)x1)->zv_vdev; 504 const uint64_t v2 = ((zil_vdev_node_t *)x2)->zv_vdev; 505 506 if (v1 < v2) 507 return (-1); 508 if (v1 > v2) 509 return (1); 510 511 return (0); 512} 513 514static lwb_t * 515zil_alloc_lwb(zilog_t *zilog, blkptr_t *bp, boolean_t slog, uint64_t txg) 516{ 517 lwb_t *lwb; 518 519 lwb = kmem_cache_alloc(zil_lwb_cache, KM_SLEEP); 520 lwb->lwb_zilog = zilog; 521 lwb->lwb_blk = *bp; 522 lwb->lwb_slog = slog; 523 lwb->lwb_state = LWB_STATE_CLOSED; 524 lwb->lwb_buf = zio_buf_alloc(BP_GET_LSIZE(bp)); 525 lwb->lwb_max_txg = txg; 526 lwb->lwb_write_zio = NULL; 527 lwb->lwb_root_zio = NULL; 528 lwb->lwb_tx = NULL; 529 lwb->lwb_issued_timestamp = 0; 530 if (BP_GET_CHECKSUM(bp) == ZIO_CHECKSUM_ZILOG2) { 531 lwb->lwb_nused = sizeof (zil_chain_t); 532 lwb->lwb_sz = BP_GET_LSIZE(bp); 533 } else { 534 lwb->lwb_nused = 0; 535 lwb->lwb_sz = BP_GET_LSIZE(bp) - sizeof (zil_chain_t); 536 } 537 538 mutex_enter(&zilog->zl_lock); 539 list_insert_tail(&zilog->zl_lwb_list, lwb); 540 mutex_exit(&zilog->zl_lock); 541 542 ASSERT(!MUTEX_HELD(&lwb->lwb_vdev_lock)); 543 ASSERT(avl_is_empty(&lwb->lwb_vdev_tree)); 544 VERIFY(list_is_empty(&lwb->lwb_waiters)); 545 546 return (lwb); 547} 548 549static void 550zil_free_lwb(zilog_t *zilog, lwb_t *lwb) 551{ 552 ASSERT(MUTEX_HELD(&zilog->zl_lock)); 553 ASSERT(!MUTEX_HELD(&lwb->lwb_vdev_lock)); 554 VERIFY(list_is_empty(&lwb->lwb_waiters)); 555 ASSERT(avl_is_empty(&lwb->lwb_vdev_tree)); 556 ASSERT3P(lwb->lwb_write_zio, ==, NULL); 557 ASSERT3P(lwb->lwb_root_zio, ==, NULL); 558 ASSERT3U(lwb->lwb_max_txg, <=, spa_syncing_txg(zilog->zl_spa)); 559 ASSERT(lwb->lwb_state == LWB_STATE_CLOSED || 560 lwb->lwb_state == LWB_STATE_DONE); 561 562 /* 563 * Clear the zilog's field to indicate this lwb is no longer 564 * valid, and prevent use-after-free errors. 565 */ 566 if (zilog->zl_last_lwb_opened == lwb) 567 zilog->zl_last_lwb_opened = NULL; 568 569 kmem_cache_free(zil_lwb_cache, lwb); 570} 571 572/* 573 * Called when we create in-memory log transactions so that we know 574 * to cleanup the itxs at the end of spa_sync(). 575 */ 576void 577zilog_dirty(zilog_t *zilog, uint64_t txg) 578{ 579 dsl_pool_t *dp = zilog->zl_dmu_pool; 580 dsl_dataset_t *ds = dmu_objset_ds(zilog->zl_os); 581 582 ASSERT(spa_writeable(zilog->zl_spa)); 583 584 if (ds->ds_is_snapshot) 585 panic("dirtying snapshot!"); 586 587 if (txg_list_add(&dp->dp_dirty_zilogs, zilog, txg)) { 588 /* up the hold count until we can be written out */ 589 dmu_buf_add_ref(ds->ds_dbuf, zilog); 590 591 zilog->zl_dirty_max_txg = MAX(txg, zilog->zl_dirty_max_txg); 592 } 593} 594 595/* 596 * Determine if the zil is dirty in the specified txg. Callers wanting to 597 * ensure that the dirty state does not change must hold the itxg_lock for 598 * the specified txg. Holding the lock will ensure that the zil cannot be 599 * dirtied (zil_itx_assign) or cleaned (zil_clean) while we check its current 600 * state. 601 */ 602boolean_t 603zilog_is_dirty_in_txg(zilog_t *zilog, uint64_t txg) 604{ 605 dsl_pool_t *dp = zilog->zl_dmu_pool; 606 607 if (txg_list_member(&dp->dp_dirty_zilogs, zilog, txg & TXG_MASK)) 608 return (B_TRUE); 609 return (B_FALSE); 610} 611 612/* 613 * Determine if the zil is dirty. The zil is considered dirty if it has 614 * any pending itx records that have not been cleaned by zil_clean(). 615 */ 616boolean_t 617zilog_is_dirty(zilog_t *zilog) 618{ 619 dsl_pool_t *dp = zilog->zl_dmu_pool; 620 621 for (int t = 0; t < TXG_SIZE; t++) { 622 if (txg_list_member(&dp->dp_dirty_zilogs, zilog, t)) 623 return (B_TRUE); 624 } 625 return (B_FALSE); 626} 627 628/* 629 * Create an on-disk intent log. 630 */ 631static lwb_t * 632zil_create(zilog_t *zilog) 633{ 634 const zil_header_t *zh = zilog->zl_header; 635 lwb_t *lwb = NULL; 636 uint64_t txg = 0; 637 dmu_tx_t *tx = NULL; 638 blkptr_t blk; 639 int error = 0; 640 boolean_t slog = FALSE; 641 642 /* 643 * Wait for any previous destroy to complete. 644 */ 645 txg_wait_synced(zilog->zl_dmu_pool, zilog->zl_destroy_txg); 646 647 ASSERT(zh->zh_claim_txg == 0); 648 ASSERT(zh->zh_replay_seq == 0); 649 650 blk = zh->zh_log; 651 652 /* 653 * Allocate an initial log block if: 654 * - there isn't one already 655 * - the existing block is the wrong endianess 656 */ 657 if (BP_IS_HOLE(&blk) || BP_SHOULD_BYTESWAP(&blk)) { 658 tx = dmu_tx_create(zilog->zl_os); 659 VERIFY0(dmu_tx_assign(tx, TXG_WAIT)); 660 dsl_dataset_dirty(dmu_objset_ds(zilog->zl_os), tx); 661 txg = dmu_tx_get_txg(tx); 662 663 if (!BP_IS_HOLE(&blk)) { 664 zio_free(zilog->zl_spa, txg, &blk); 665 BP_ZERO(&blk); 666 } 667 668 error = zio_alloc_zil(zilog->zl_spa, txg, &blk, NULL, 669 ZIL_MIN_BLKSZ, &slog); 670 671 if (error == 0) 672 zil_init_log_chain(zilog, &blk); 673 } 674 675 /* 676 * Allocate a log write block (lwb) for the first log block. 677 */ 678 if (error == 0) 679 lwb = zil_alloc_lwb(zilog, &blk, slog, txg); 680 681 /* 682 * If we just allocated the first log block, commit our transaction 683 * and wait for zil_sync() to stuff the block poiner into zh_log. 684 * (zh is part of the MOS, so we cannot modify it in open context.) 685 */ 686 if (tx != NULL) { 687 dmu_tx_commit(tx); 688 txg_wait_synced(zilog->zl_dmu_pool, txg); 689 } 690 691 ASSERT(bcmp(&blk, &zh->zh_log, sizeof (blk)) == 0); 692 693 return (lwb); 694} 695 696/* 697 * In one tx, free all log blocks and clear the log header. If keep_first 698 * is set, then we're replaying a log with no content. We want to keep the 699 * first block, however, so that the first synchronous transaction doesn't 700 * require a txg_wait_synced() in zil_create(). We don't need to 701 * txg_wait_synced() here either when keep_first is set, because both 702 * zil_create() and zil_destroy() will wait for any in-progress destroys 703 * to complete. 704 */ 705void 706zil_destroy(zilog_t *zilog, boolean_t keep_first) 707{ 708 const zil_header_t *zh = zilog->zl_header; 709 lwb_t *lwb; 710 dmu_tx_t *tx; 711 uint64_t txg; 712 713 /* 714 * Wait for any previous destroy to complete. 715 */ 716 txg_wait_synced(zilog->zl_dmu_pool, zilog->zl_destroy_txg); 717 718 zilog->zl_old_header = *zh; /* debugging aid */ 719 720 if (BP_IS_HOLE(&zh->zh_log)) 721 return; 722 723 tx = dmu_tx_create(zilog->zl_os); 724 VERIFY0(dmu_tx_assign(tx, TXG_WAIT)); 725 dsl_dataset_dirty(dmu_objset_ds(zilog->zl_os), tx); 726 txg = dmu_tx_get_txg(tx); 727 728 mutex_enter(&zilog->zl_lock); 729 730 ASSERT3U(zilog->zl_destroy_txg, <, txg); 731 zilog->zl_destroy_txg = txg; 732 zilog->zl_keep_first = keep_first; 733 734 if (!list_is_empty(&zilog->zl_lwb_list)) { 735 ASSERT(zh->zh_claim_txg == 0); 736 VERIFY(!keep_first); 737 while ((lwb = list_head(&zilog->zl_lwb_list)) != NULL) { 738 list_remove(&zilog->zl_lwb_list, lwb); 739 if (lwb->lwb_buf != NULL) 740 zio_buf_free(lwb->lwb_buf, lwb->lwb_sz); 741 zio_free(zilog->zl_spa, txg, &lwb->lwb_blk); 742 zil_free_lwb(zilog, lwb); 743 } 744 } else if (!keep_first) { 745 zil_destroy_sync(zilog, tx); 746 } 747 mutex_exit(&zilog->zl_lock); 748 749 dmu_tx_commit(tx); 750} 751 752void 753zil_destroy_sync(zilog_t *zilog, dmu_tx_t *tx) 754{ 755 ASSERT(list_is_empty(&zilog->zl_lwb_list)); 756 (void) zil_parse(zilog, zil_free_log_block, 757 zil_free_log_record, tx, zilog->zl_header->zh_claim_txg); 758} 759 760int 761zil_claim(dsl_pool_t *dp, dsl_dataset_t *ds, void *txarg) 762{ 763 dmu_tx_t *tx = txarg; 764 zilog_t *zilog; 765 uint64_t first_txg; 766 zil_header_t *zh; 767 objset_t *os; 768 int error; 769 770 error = dmu_objset_own_obj(dp, ds->ds_object, 771 DMU_OST_ANY, B_FALSE, FTAG, &os); 772 if (error != 0) { 773 /* 774 * EBUSY indicates that the objset is inconsistent, in which 775 * case it can not have a ZIL. 776 */ 777 if (error != EBUSY) { 778 cmn_err(CE_WARN, "can't open objset for %llu, error %u", 779 (unsigned long long)ds->ds_object, error); 780 } 781 return (0); 782 } 783 784 zilog = dmu_objset_zil(os); 785 zh = zil_header_in_syncing_context(zilog); 786 ASSERT3U(tx->tx_txg, ==, spa_first_txg(zilog->zl_spa)); 787 first_txg = spa_min_claim_txg(zilog->zl_spa); 788 789 /* 790 * If the spa_log_state is not set to be cleared, check whether 791 * the current uberblock is a checkpoint one and if the current 792 * header has been claimed before moving on. 793 * 794 * If the current uberblock is a checkpointed uberblock then 795 * one of the following scenarios took place: 796 * 797 * 1] We are currently rewinding to the checkpoint of the pool. 798 * 2] We crashed in the middle of a checkpoint rewind but we 799 * did manage to write the checkpointed uberblock to the 800 * vdev labels, so when we tried to import the pool again 801 * the checkpointed uberblock was selected from the import 802 * procedure. 803 * 804 * In both cases we want to zero out all the ZIL blocks, except 805 * the ones that have been claimed at the time of the checkpoint 806 * (their zh_claim_txg != 0). The reason is that these blocks 807 * may be corrupted since we may have reused their locations on 808 * disk after we took the checkpoint. 809 * 810 * We could try to set spa_log_state to SPA_LOG_CLEAR earlier 811 * when we first figure out whether the current uberblock is 812 * checkpointed or not. Unfortunately, that would discard all 813 * the logs, including the ones that are claimed, and we would 814 * leak space. 815 */ 816 if (spa_get_log_state(zilog->zl_spa) == SPA_LOG_CLEAR || 817 (zilog->zl_spa->spa_uberblock.ub_checkpoint_txg != 0 && 818 zh->zh_claim_txg == 0)) { 819 if (!BP_IS_HOLE(&zh->zh_log)) { 820 (void) zil_parse(zilog, zil_clear_log_block, 821 zil_noop_log_record, tx, first_txg); 822 } 823 BP_ZERO(&zh->zh_log); 824 dsl_dataset_dirty(dmu_objset_ds(os), tx); 825 dmu_objset_disown(os, FTAG); 826 return (0); 827 } 828 829 /* 830 * If we are not rewinding and opening the pool normally, then 831 * the min_claim_txg should be equal to the first txg of the pool. 832 */ 833 ASSERT3U(first_txg, ==, spa_first_txg(zilog->zl_spa)); 834 835 /* 836 * Claim all log blocks if we haven't already done so, and remember 837 * the highest claimed sequence number. This ensures that if we can 838 * read only part of the log now (e.g. due to a missing device), 839 * but we can read the entire log later, we will not try to replay 840 * or destroy beyond the last block we successfully claimed. 841 */ 842 ASSERT3U(zh->zh_claim_txg, <=, first_txg); 843 if (zh->zh_claim_txg == 0 && !BP_IS_HOLE(&zh->zh_log)) { 844 (void) zil_parse(zilog, zil_claim_log_block, 845 zil_claim_log_record, tx, first_txg); 846 zh->zh_claim_txg = first_txg; 847 zh->zh_claim_blk_seq = zilog->zl_parse_blk_seq; 848 zh->zh_claim_lr_seq = zilog->zl_parse_lr_seq; 849 if (zilog->zl_parse_lr_count || zilog->zl_parse_blk_count > 1) 850 zh->zh_flags |= ZIL_REPLAY_NEEDED; 851 zh->zh_flags |= ZIL_CLAIM_LR_SEQ_VALID; 852 dsl_dataset_dirty(dmu_objset_ds(os), tx); 853 } 854 855 ASSERT3U(first_txg, ==, (spa_last_synced_txg(zilog->zl_spa) + 1)); 856 dmu_objset_disown(os, FTAG); 857 return (0); 858} 859 860/* 861 * Check the log by walking the log chain. 862 * Checksum errors are ok as they indicate the end of the chain. 863 * Any other error (no device or read failure) returns an error. 864 */ 865/* ARGSUSED */ 866int 867zil_check_log_chain(dsl_pool_t *dp, dsl_dataset_t *ds, void *tx) 868{ 869 zilog_t *zilog; 870 objset_t *os; 871 blkptr_t *bp; 872 int error; 873 874 ASSERT(tx == NULL); 875 876 error = dmu_objset_from_ds(ds, &os); 877 if (error != 0) { 878 cmn_err(CE_WARN, "can't open objset %llu, error %d", 879 (unsigned long long)ds->ds_object, error); 880 return (0); 881 } 882 883 zilog = dmu_objset_zil(os); 884 bp = (blkptr_t *)&zilog->zl_header->zh_log; 885 886 if (!BP_IS_HOLE(bp)) { 887 vdev_t *vd; 888 boolean_t valid = B_TRUE; 889 890 /* 891 * Check the first block and determine if it's on a log device 892 * which may have been removed or faulted prior to loading this 893 * pool. If so, there's no point in checking the rest of the 894 * log as its content should have already been synced to the 895 * pool. 896 */ 897 spa_config_enter(os->os_spa, SCL_STATE, FTAG, RW_READER); 898 vd = vdev_lookup_top(os->os_spa, DVA_GET_VDEV(&bp->blk_dva[0])); 899 if (vd->vdev_islog && vdev_is_dead(vd)) 900 valid = vdev_log_state_valid(vd); 901 spa_config_exit(os->os_spa, SCL_STATE, FTAG); 902 903 if (!valid) 904 return (0); 905 906 /* 907 * Check whether the current uberblock is checkpointed (e.g. 908 * we are rewinding) and whether the current header has been 909 * claimed or not. If it hasn't then skip verifying it. We 910 * do this because its ZIL blocks may be part of the pool's 911 * state before the rewind, which is no longer valid. 912 */ 913 zil_header_t *zh = zil_header_in_syncing_context(zilog); 914 if (zilog->zl_spa->spa_uberblock.ub_checkpoint_txg != 0 && 915 zh->zh_claim_txg == 0) 916 return (0); 917 } 918 919 /* 920 * Because tx == NULL, zil_claim_log_block() will not actually claim 921 * any blocks, but just determine whether it is possible to do so. 922 * In addition to checking the log chain, zil_claim_log_block() 923 * will invoke zio_claim() with a done func of spa_claim_notify(), 924 * which will update spa_max_claim_txg. See spa_load() for details. 925 */ 926 error = zil_parse(zilog, zil_claim_log_block, zil_claim_log_record, tx, 927 zilog->zl_header->zh_claim_txg ? -1ULL : 928 spa_min_claim_txg(os->os_spa)); 929 930 return ((error == ECKSUM || error == ENOENT) ? 0 : error); 931} 932 933/* 934 * When an itx is "skipped", this function is used to properly mark the 935 * waiter as "done, and signal any thread(s) waiting on it. An itx can 936 * be skipped (and not committed to an lwb) for a variety of reasons, 937 * one of them being that the itx was committed via spa_sync(), prior to 938 * it being committed to an lwb; this can happen if a thread calling 939 * zil_commit() is racing with spa_sync(). 940 */ 941static void 942zil_commit_waiter_skip(zil_commit_waiter_t *zcw) 943{ 944 mutex_enter(&zcw->zcw_lock); 945 ASSERT3B(zcw->zcw_done, ==, B_FALSE); 946 zcw->zcw_done = B_TRUE; 947 cv_broadcast(&zcw->zcw_cv); 948 mutex_exit(&zcw->zcw_lock); 949} 950 951/* 952 * This function is used when the given waiter is to be linked into an 953 * lwb's "lwb_waiter" list; i.e. when the itx is committed to the lwb. 954 * At this point, the waiter will no longer be referenced by the itx, 955 * and instead, will be referenced by the lwb. 956 */ 957static void 958zil_commit_waiter_link_lwb(zil_commit_waiter_t *zcw, lwb_t *lwb) 959{ 960 /* 961 * The lwb_waiters field of the lwb is protected by the zilog's 962 * zl_lock, thus it must be held when calling this function. 963 */ 964 ASSERT(MUTEX_HELD(&lwb->lwb_zilog->zl_lock)); 965 966 mutex_enter(&zcw->zcw_lock); 967 ASSERT(!list_link_active(&zcw->zcw_node)); 968 ASSERT3P(zcw->zcw_lwb, ==, NULL); 969 ASSERT3P(lwb, !=, NULL); 970 ASSERT(lwb->lwb_state == LWB_STATE_OPENED || 971 lwb->lwb_state == LWB_STATE_ISSUED); 972 973 list_insert_tail(&lwb->lwb_waiters, zcw); 974 zcw->zcw_lwb = lwb; 975 mutex_exit(&zcw->zcw_lock); 976} 977 978/* 979 * This function is used when zio_alloc_zil() fails to allocate a ZIL 980 * block, and the given waiter must be linked to the "nolwb waiters" 981 * list inside of zil_process_commit_list(). 982 */ 983static void 984zil_commit_waiter_link_nolwb(zil_commit_waiter_t *zcw, list_t *nolwb) 985{ 986 mutex_enter(&zcw->zcw_lock); 987 ASSERT(!list_link_active(&zcw->zcw_node)); 988 ASSERT3P(zcw->zcw_lwb, ==, NULL); 989 list_insert_tail(nolwb, zcw); 990 mutex_exit(&zcw->zcw_lock); 991} 992 993void 994zil_lwb_add_block(lwb_t *lwb, const blkptr_t *bp) 995{ 996 avl_tree_t *t = &lwb->lwb_vdev_tree; 997 avl_index_t where; 998 zil_vdev_node_t *zv, zvsearch; 999 int ndvas = BP_GET_NDVAS(bp); 1000 int i; 1001 1002 if (zfs_nocacheflush) 1003 return; 1004 1005 mutex_enter(&lwb->lwb_vdev_lock); 1006 for (i = 0; i < ndvas; i++) { 1007 zvsearch.zv_vdev = DVA_GET_VDEV(&bp->blk_dva[i]); 1008 if (avl_find(t, &zvsearch, &where) == NULL) { 1009 zv = kmem_alloc(sizeof (*zv), KM_SLEEP); 1010 zv->zv_vdev = zvsearch.zv_vdev; 1011 avl_insert(t, zv, where); 1012 } 1013 } 1014 mutex_exit(&lwb->lwb_vdev_lock); 1015} 1016 1017void 1018zil_lwb_add_txg(lwb_t *lwb, uint64_t txg) 1019{ 1020 lwb->lwb_max_txg = MAX(lwb->lwb_max_txg, txg); 1021} 1022 1023/* 1024 * This function is a called after all VDEVs associated with a given lwb 1025 * write have completed their DKIOCFLUSHWRITECACHE command; or as soon 1026 * as the lwb write completes, if "zfs_nocacheflush" is set. 1027 * 1028 * The intention is for this function to be called as soon as the 1029 * contents of an lwb are considered "stable" on disk, and will survive 1030 * any sudden loss of power. At this point, any threads waiting for the 1031 * lwb to reach this state are signalled, and the "waiter" structures 1032 * are marked "done". 1033 */ 1034static void 1035zil_lwb_flush_vdevs_done(zio_t *zio) 1036{ 1037 lwb_t *lwb = zio->io_private; 1038 zilog_t *zilog = lwb->lwb_zilog; 1039 dmu_tx_t *tx = lwb->lwb_tx; 1040 zil_commit_waiter_t *zcw; 1041 1042 spa_config_exit(zilog->zl_spa, SCL_STATE, lwb); 1043 1044 zio_buf_free(lwb->lwb_buf, lwb->lwb_sz); 1045 1046 mutex_enter(&zilog->zl_lock); 1047 1048 /* 1049 * Ensure the lwb buffer pointer is cleared before releasing the 1050 * txg. If we have had an allocation failure and the txg is 1051 * waiting to sync then we want zil_sync() to remove the lwb so 1052 * that it's not picked up as the next new one in 1053 * zil_process_commit_list(). zil_sync() will only remove the 1054 * lwb if lwb_buf is null. 1055 */ 1056 lwb->lwb_buf = NULL; 1057 lwb->lwb_tx = NULL; 1058 1059 ASSERT3U(lwb->lwb_issued_timestamp, >, 0); 1060 zilog->zl_last_lwb_latency = gethrtime() - lwb->lwb_issued_timestamp; 1061 1062 lwb->lwb_root_zio = NULL; 1063 lwb->lwb_state = LWB_STATE_DONE; 1064 1065 if (zilog->zl_last_lwb_opened == lwb) { 1066 /* 1067 * Remember the highest committed log sequence number 1068 * for ztest. We only update this value when all the log 1069 * writes succeeded, because ztest wants to ASSERT that 1070 * it got the whole log chain. 1071 */ 1072 zilog->zl_commit_lr_seq = zilog->zl_lr_seq; 1073 } 1074 1075 while ((zcw = list_head(&lwb->lwb_waiters)) != NULL) { 1076 mutex_enter(&zcw->zcw_lock); 1077 1078 ASSERT(list_link_active(&zcw->zcw_node)); 1079 list_remove(&lwb->lwb_waiters, zcw); 1080 1081 ASSERT3P(zcw->zcw_lwb, ==, lwb); 1082 zcw->zcw_lwb = NULL; 1083 1084 zcw->zcw_zio_error = zio->io_error; 1085 1086 ASSERT3B(zcw->zcw_done, ==, B_FALSE); 1087 zcw->zcw_done = B_TRUE; 1088 cv_broadcast(&zcw->zcw_cv); 1089 1090 mutex_exit(&zcw->zcw_lock); 1091 } 1092 1093 mutex_exit(&zilog->zl_lock); 1094 1095 /* 1096 * Now that we've written this log block, we have a stable pointer 1097 * to the next block in the chain, so it's OK to let the txg in 1098 * which we allocated the next block sync. 1099 */ 1100 dmu_tx_commit(tx); 1101} 1102 1103/* 1104 * This is called when an lwb write completes. This means, this specific 1105 * lwb was written to disk, and all dependent lwb have also been 1106 * written to disk. 1107 * 1108 * At this point, a DKIOCFLUSHWRITECACHE command hasn't been issued to 1109 * the VDEVs involved in writing out this specific lwb. The lwb will be 1110 * "done" once zil_lwb_flush_vdevs_done() is called, which occurs in the 1111 * zio completion callback for the lwb's root zio. 1112 */ 1113static void 1114zil_lwb_write_done(zio_t *zio) 1115{ 1116 lwb_t *lwb = zio->io_private; 1117 spa_t *spa = zio->io_spa; 1118 zilog_t *zilog = lwb->lwb_zilog; 1119 avl_tree_t *t = &lwb->lwb_vdev_tree; 1120 void *cookie = NULL; 1121 zil_vdev_node_t *zv; 1122 1123 ASSERT3S(spa_config_held(spa, SCL_STATE, RW_READER), !=, 0); 1124 1125 ASSERT(BP_GET_COMPRESS(zio->io_bp) == ZIO_COMPRESS_OFF); 1126 ASSERT(BP_GET_TYPE(zio->io_bp) == DMU_OT_INTENT_LOG); 1127 ASSERT(BP_GET_LEVEL(zio->io_bp) == 0); 1128 ASSERT(BP_GET_BYTEORDER(zio->io_bp) == ZFS_HOST_BYTEORDER); 1129 ASSERT(!BP_IS_GANG(zio->io_bp)); 1130 ASSERT(!BP_IS_HOLE(zio->io_bp)); 1131 ASSERT(BP_GET_FILL(zio->io_bp) == 0); 1132 1133 abd_put(zio->io_abd); 1134 1135 ASSERT3S(lwb->lwb_state, ==, LWB_STATE_ISSUED); 1136 1137 mutex_enter(&zilog->zl_lock); 1138 lwb->lwb_write_zio = NULL; 1139 mutex_exit(&zilog->zl_lock); 1140 1141 if (avl_numnodes(t) == 0) 1142 return; 1143 1144 /* 1145 * If there was an IO error, we're not going to call zio_flush() 1146 * on these vdevs, so we simply empty the tree and free the 1147 * nodes. We avoid calling zio_flush() since there isn't any 1148 * good reason for doing so, after the lwb block failed to be 1149 * written out. 1150 */ 1151 if (zio->io_error != 0) { 1152 while ((zv = avl_destroy_nodes(t, &cookie)) != NULL) 1153 kmem_free(zv, sizeof (*zv)); 1154 return; 1155 } 1156 1157 while ((zv = avl_destroy_nodes(t, &cookie)) != NULL) { 1158 vdev_t *vd = vdev_lookup_top(spa, zv->zv_vdev); 1159 if (vd != NULL) 1160 zio_flush(lwb->lwb_root_zio, vd); 1161 kmem_free(zv, sizeof (*zv)); 1162 } 1163} 1164 1165/* 1166 * This function's purpose is to "open" an lwb such that it is ready to 1167 * accept new itxs being committed to it. To do this, the lwb's zio 1168 * structures are created, and linked to the lwb. This function is 1169 * idempotent; if the passed in lwb has already been opened, this 1170 * function is essentially a no-op. 1171 */ 1172static void 1173zil_lwb_write_open(zilog_t *zilog, lwb_t *lwb) 1174{ 1175 zbookmark_phys_t zb; 1176 zio_priority_t prio; 1177 1178 ASSERT(MUTEX_HELD(&zilog->zl_issuer_lock)); 1179 ASSERT3P(lwb, !=, NULL); 1180 EQUIV(lwb->lwb_root_zio == NULL, lwb->lwb_state == LWB_STATE_CLOSED); 1181 EQUIV(lwb->lwb_root_zio != NULL, lwb->lwb_state == LWB_STATE_OPENED); 1182 1183 SET_BOOKMARK(&zb, lwb->lwb_blk.blk_cksum.zc_word[ZIL_ZC_OBJSET], 1184 ZB_ZIL_OBJECT, ZB_ZIL_LEVEL, 1185 lwb->lwb_blk.blk_cksum.zc_word[ZIL_ZC_SEQ]); 1186 1187 if (lwb->lwb_root_zio == NULL) { 1188 abd_t *lwb_abd = abd_get_from_buf(lwb->lwb_buf, 1189 BP_GET_LSIZE(&lwb->lwb_blk)); 1190 1191 if (!lwb->lwb_slog || zilog->zl_cur_used <= zil_slog_bulk) 1192 prio = ZIO_PRIORITY_SYNC_WRITE; 1193 else 1194 prio = ZIO_PRIORITY_ASYNC_WRITE; 1195 1196 lwb->lwb_root_zio = zio_root(zilog->zl_spa, 1197 zil_lwb_flush_vdevs_done, lwb, ZIO_FLAG_CANFAIL); 1198 ASSERT3P(lwb->lwb_root_zio, !=, NULL); 1199 1200 lwb->lwb_write_zio = zio_rewrite(lwb->lwb_root_zio, 1201 zilog->zl_spa, 0, &lwb->lwb_blk, lwb_abd, 1202 BP_GET_LSIZE(&lwb->lwb_blk), zil_lwb_write_done, lwb, 1203 prio, ZIO_FLAG_CANFAIL | ZIO_FLAG_DONT_PROPAGATE, &zb); 1204 ASSERT3P(lwb->lwb_write_zio, !=, NULL); 1205 1206 lwb->lwb_state = LWB_STATE_OPENED; 1207 1208 mutex_enter(&zilog->zl_lock); 1209 1210 /* 1211 * The zilog's "zl_last_lwb_opened" field is used to 1212 * build the lwb/zio dependency chain, which is used to 1213 * preserve the ordering of lwb completions that is 1214 * required by the semantics of the ZIL. Each new lwb 1215 * zio becomes a parent of the "previous" lwb zio, such 1216 * that the new lwb's zio cannot complete until the 1217 * "previous" lwb's zio completes. 1218 * 1219 * This is required by the semantics of zil_commit(); 1220 * the commit waiters attached to the lwbs will be woken 1221 * in the lwb zio's completion callback, so this zio 1222 * dependency graph ensures the waiters are woken in the 1223 * correct order (the same order the lwbs were created). 1224 */ 1225 lwb_t *last_lwb_opened = zilog->zl_last_lwb_opened; 1226 if (last_lwb_opened != NULL && 1227 last_lwb_opened->lwb_state != LWB_STATE_DONE) { 1228 ASSERT(last_lwb_opened->lwb_state == LWB_STATE_OPENED || 1229 last_lwb_opened->lwb_state == LWB_STATE_ISSUED); 1230 ASSERT3P(last_lwb_opened->lwb_root_zio, !=, NULL); 1231 zio_add_child(lwb->lwb_root_zio, 1232 last_lwb_opened->lwb_root_zio); 1233 } 1234 zilog->zl_last_lwb_opened = lwb; 1235 1236 mutex_exit(&zilog->zl_lock); 1237 } 1238 1239 ASSERT3P(lwb->lwb_root_zio, !=, NULL); 1240 ASSERT3P(lwb->lwb_write_zio, !=, NULL); 1241 ASSERT3S(lwb->lwb_state, ==, LWB_STATE_OPENED); 1242} 1243 1244/* 1245 * Define a limited set of intent log block sizes. 1246 * 1247 * These must be a multiple of 4KB. Note only the amount used (again 1248 * aligned to 4KB) actually gets written. However, we can't always just 1249 * allocate SPA_OLD_MAXBLOCKSIZE as the slog space could be exhausted. 1250 */ 1251uint64_t zil_block_buckets[] = { 1252 4096, /* non TX_WRITE */ 1253 8192+4096, /* data base */ 1254 32*1024 + 4096, /* NFS writes */ 1255 UINT64_MAX 1256}; 1257 1258/* 1259 * Start a log block write and advance to the next log block. 1260 * Calls are serialized. 1261 */ 1262static lwb_t * 1263zil_lwb_write_issue(zilog_t *zilog, lwb_t *lwb) 1264{ 1265 lwb_t *nlwb = NULL; 1266 zil_chain_t *zilc; 1267 spa_t *spa = zilog->zl_spa; 1268 blkptr_t *bp; 1269 dmu_tx_t *tx; 1270 uint64_t txg; 1271 uint64_t zil_blksz, wsz; 1272 int i, error; 1273 boolean_t slog; 1274 1275 ASSERT(MUTEX_HELD(&zilog->zl_issuer_lock)); 1276 ASSERT3P(lwb->lwb_root_zio, !=, NULL); 1277 ASSERT3P(lwb->lwb_write_zio, !=, NULL); 1278 ASSERT3S(lwb->lwb_state, ==, LWB_STATE_OPENED); 1279 1280 if (BP_GET_CHECKSUM(&lwb->lwb_blk) == ZIO_CHECKSUM_ZILOG2) { 1281 zilc = (zil_chain_t *)lwb->lwb_buf; 1282 bp = &zilc->zc_next_blk; 1283 } else { 1284 zilc = (zil_chain_t *)(lwb->lwb_buf + lwb->lwb_sz); 1285 bp = &zilc->zc_next_blk; 1286 } 1287 1288 ASSERT(lwb->lwb_nused <= lwb->lwb_sz); 1289 1290 /* 1291 * Allocate the next block and save its address in this block 1292 * before writing it in order to establish the log chain. 1293 * Note that if the allocation of nlwb synced before we wrote 1294 * the block that points at it (lwb), we'd leak it if we crashed. 1295 * Therefore, we don't do dmu_tx_commit() until zil_lwb_write_done(). 1296 * We dirty the dataset to ensure that zil_sync() will be called 1297 * to clean up in the event of allocation failure or I/O failure. 1298 */ 1299 1300 tx = dmu_tx_create(zilog->zl_os); 1301 1302 /* 1303 * Since we are not going to create any new dirty data, and we 1304 * can even help with clearing the existing dirty data, we 1305 * should not be subject to the dirty data based delays. We 1306 * use TXG_NOTHROTTLE to bypass the delay mechanism. 1307 */ 1308 VERIFY0(dmu_tx_assign(tx, TXG_WAIT | TXG_NOTHROTTLE)); 1309 1310 dsl_dataset_dirty(dmu_objset_ds(zilog->zl_os), tx); 1311 txg = dmu_tx_get_txg(tx); 1312 1313 lwb->lwb_tx = tx; 1314 1315 /* 1316 * Log blocks are pre-allocated. Here we select the size of the next 1317 * block, based on size used in the last block. 1318 * - first find the smallest bucket that will fit the block from a 1319 * limited set of block sizes. This is because it's faster to write 1320 * blocks allocated from the same metaslab as they are adjacent or 1321 * close. 1322 * - next find the maximum from the new suggested size and an array of 1323 * previous sizes. This lessens a picket fence effect of wrongly 1324 * guesssing the size if we have a stream of say 2k, 64k, 2k, 64k 1325 * requests. 1326 * 1327 * Note we only write what is used, but we can't just allocate 1328 * the maximum block size because we can exhaust the available 1329 * pool log space. 1330 */ 1331 zil_blksz = zilog->zl_cur_used + sizeof (zil_chain_t); 1332 for (i = 0; zil_blksz > zil_block_buckets[i]; i++) 1333 continue; 1334 zil_blksz = zil_block_buckets[i]; 1335 if (zil_blksz == UINT64_MAX) 1336 zil_blksz = SPA_OLD_MAXBLOCKSIZE; 1337 zilog->zl_prev_blks[zilog->zl_prev_rotor] = zil_blksz; 1338 for (i = 0; i < ZIL_PREV_BLKS; i++) 1339 zil_blksz = MAX(zil_blksz, zilog->zl_prev_blks[i]); 1340 zilog->zl_prev_rotor = (zilog->zl_prev_rotor + 1) & (ZIL_PREV_BLKS - 1); 1341 1342 BP_ZERO(bp); 1343 1344 /* pass the old blkptr in order to spread log blocks across devs */ 1345 error = zio_alloc_zil(spa, txg, bp, &lwb->lwb_blk, zil_blksz, &slog); 1346 if (error == 0) { 1347 ASSERT3U(bp->blk_birth, ==, txg); 1348 bp->blk_cksum = lwb->lwb_blk.blk_cksum; 1349 bp->blk_cksum.zc_word[ZIL_ZC_SEQ]++; 1350 1351 /* 1352 * Allocate a new log write block (lwb). 1353 */ 1354 nlwb = zil_alloc_lwb(zilog, bp, slog, txg); 1355 } 1356 1357 if (BP_GET_CHECKSUM(&lwb->lwb_blk) == ZIO_CHECKSUM_ZILOG2) { 1358 /* For Slim ZIL only write what is used. */ 1359 wsz = P2ROUNDUP_TYPED(lwb->lwb_nused, ZIL_MIN_BLKSZ, uint64_t); 1360 ASSERT3U(wsz, <=, lwb->lwb_sz); 1361 zio_shrink(lwb->lwb_write_zio, wsz); 1362 1363 } else { 1364 wsz = lwb->lwb_sz; 1365 } 1366 1367 zilc->zc_pad = 0; 1368 zilc->zc_nused = lwb->lwb_nused; 1369 zilc->zc_eck.zec_cksum = lwb->lwb_blk.blk_cksum; 1370 1371 /* 1372 * clear unused data for security 1373 */ 1374 bzero(lwb->lwb_buf + lwb->lwb_nused, wsz - lwb->lwb_nused); 1375 1376 spa_config_enter(zilog->zl_spa, SCL_STATE, lwb, RW_READER); 1377 1378 zil_lwb_add_block(lwb, &lwb->lwb_blk); 1379 lwb->lwb_issued_timestamp = gethrtime(); 1380 lwb->lwb_state = LWB_STATE_ISSUED; 1381 1382 zio_nowait(lwb->lwb_root_zio); 1383 zio_nowait(lwb->lwb_write_zio); 1384 1385 /* 1386 * If there was an allocation failure then nlwb will be null which 1387 * forces a txg_wait_synced(). 1388 */ 1389 return (nlwb); 1390} 1391 1392static lwb_t * 1393zil_lwb_commit(zilog_t *zilog, itx_t *itx, lwb_t *lwb) 1394{ 1395 lr_t *lrcb, *lrc; 1396 lr_write_t *lrwb, *lrw; 1397 char *lr_buf; 1398 uint64_t dlen, dnow, lwb_sp, reclen, txg; 1399 1400 ASSERT(MUTEX_HELD(&zilog->zl_issuer_lock)); 1401 ASSERT3P(lwb, !=, NULL); 1402 ASSERT3P(lwb->lwb_buf, !=, NULL); 1403 1404 zil_lwb_write_open(zilog, lwb); 1405 1406 lrc = &itx->itx_lr; 1407 lrw = (lr_write_t *)lrc; 1408 1409 /* 1410 * A commit itx doesn't represent any on-disk state; instead 1411 * it's simply used as a place holder on the commit list, and 1412 * provides a mechanism for attaching a "commit waiter" onto the 1413 * correct lwb (such that the waiter can be signalled upon 1414 * completion of that lwb). Thus, we don't process this itx's 1415 * log record if it's a commit itx (these itx's don't have log 1416 * records), and instead link the itx's waiter onto the lwb's 1417 * list of waiters. 1418 * 1419 * For more details, see the comment above zil_commit(). 1420 */ 1421 if (lrc->lrc_txtype == TX_COMMIT) { 1422 mutex_enter(&zilog->zl_lock); 1423 zil_commit_waiter_link_lwb(itx->itx_private, lwb); 1424 itx->itx_private = NULL; 1425 mutex_exit(&zilog->zl_lock); 1426 return (lwb); 1427 } 1428 1429 if (lrc->lrc_txtype == TX_WRITE && itx->itx_wr_state == WR_NEED_COPY) { 1430 dlen = P2ROUNDUP_TYPED( 1431 lrw->lr_length, sizeof (uint64_t), uint64_t); 1432 } else { 1433 dlen = 0; 1434 } 1435 reclen = lrc->lrc_reclen; 1436 zilog->zl_cur_used += (reclen + dlen); 1437 txg = lrc->lrc_txg; 1438 1439 ASSERT3U(zilog->zl_cur_used, <, UINT64_MAX - (reclen + dlen)); 1440 1441cont: 1442 /* 1443 * If this record won't fit in the current log block, start a new one. 1444 * For WR_NEED_COPY optimize layout for minimal number of chunks. 1445 */ 1446 lwb_sp = lwb->lwb_sz - lwb->lwb_nused; 1447 if (reclen > lwb_sp || (reclen + dlen > lwb_sp && 1448 lwb_sp < ZIL_MAX_WASTE_SPACE && (dlen % ZIL_MAX_LOG_DATA == 0 || 1449 lwb_sp < reclen + dlen % ZIL_MAX_LOG_DATA))) { 1450 lwb = zil_lwb_write_issue(zilog, lwb); 1451 if (lwb == NULL) 1452 return (NULL); 1453 zil_lwb_write_open(zilog, lwb); 1454 ASSERT(LWB_EMPTY(lwb)); 1455 lwb_sp = lwb->lwb_sz - lwb->lwb_nused; 1456 ASSERT3U(reclen + MIN(dlen, sizeof (uint64_t)), <=, lwb_sp); 1457 } 1458 1459 dnow = MIN(dlen, lwb_sp - reclen); 1460 lr_buf = lwb->lwb_buf + lwb->lwb_nused; 1461 bcopy(lrc, lr_buf, reclen); 1462 lrcb = (lr_t *)lr_buf; /* Like lrc, but inside lwb. */ 1463 lrwb = (lr_write_t *)lrcb; /* Like lrw, but inside lwb. */ 1464 1465 /* 1466 * If it's a write, fetch the data or get its blkptr as appropriate. 1467 */ 1468 if (lrc->lrc_txtype == TX_WRITE) { 1469 if (txg > spa_freeze_txg(zilog->zl_spa)) 1470 txg_wait_synced(zilog->zl_dmu_pool, txg); 1471 if (itx->itx_wr_state != WR_COPIED) { 1472 char *dbuf; 1473 int error; 1474 1475 if (itx->itx_wr_state == WR_NEED_COPY) { 1476 dbuf = lr_buf + reclen; 1477 lrcb->lrc_reclen += dnow; 1478 if (lrwb->lr_length > dnow) 1479 lrwb->lr_length = dnow; 1480 lrw->lr_offset += dnow; 1481 lrw->lr_length -= dnow; 1482 } else { 1483 ASSERT(itx->itx_wr_state == WR_INDIRECT); 1484 dbuf = NULL; 1485 } 1486 1487 /* 1488 * We pass in the "lwb_write_zio" rather than 1489 * "lwb_root_zio" so that the "lwb_write_zio" 1490 * becomes the parent of any zio's created by 1491 * the "zl_get_data" callback. The vdevs are 1492 * flushed after the "lwb_write_zio" completes, 1493 * so we want to make sure that completion 1494 * callback waits for these additional zio's, 1495 * such that the vdevs used by those zio's will 1496 * be included in the lwb's vdev tree, and those 1497 * vdevs will be properly flushed. If we passed 1498 * in "lwb_root_zio" here, then these additional 1499 * vdevs may not be flushed; e.g. if these zio's 1500 * completed after "lwb_write_zio" completed. 1501 */ 1502 error = zilog->zl_get_data(itx->itx_private, 1503 lrwb, dbuf, lwb, lwb->lwb_write_zio); 1504 1505 if (error == EIO) { 1506 txg_wait_synced(zilog->zl_dmu_pool, txg); 1507 return (lwb); 1508 } 1509 if (error != 0) { 1510 ASSERT(error == ENOENT || error == EEXIST || 1511 error == EALREADY); 1512 return (lwb); 1513 } 1514 } 1515 } 1516 1517 /* 1518 * We're actually making an entry, so update lrc_seq to be the 1519 * log record sequence number. Note that this is generally not 1520 * equal to the itx sequence number because not all transactions 1521 * are synchronous, and sometimes spa_sync() gets there first. 1522 */ 1523 lrcb->lrc_seq = ++zilog->zl_lr_seq; 1524 lwb->lwb_nused += reclen + dnow; 1525 1526 zil_lwb_add_txg(lwb, txg); 1527 1528 ASSERT3U(lwb->lwb_nused, <=, lwb->lwb_sz); 1529 ASSERT0(P2PHASE(lwb->lwb_nused, sizeof (uint64_t))); 1530 1531 dlen -= dnow; 1532 if (dlen > 0) { 1533 zilog->zl_cur_used += reclen; 1534 goto cont; 1535 } 1536 1537 return (lwb); 1538} 1539 1540itx_t * 1541zil_itx_create(uint64_t txtype, size_t lrsize) 1542{ 1543 itx_t *itx; 1544 1545 lrsize = P2ROUNDUP_TYPED(lrsize, sizeof (uint64_t), size_t); 1546 1547 itx = kmem_alloc(offsetof(itx_t, itx_lr) + lrsize, KM_SLEEP); 1548 itx->itx_lr.lrc_txtype = txtype; 1549 itx->itx_lr.lrc_reclen = lrsize; 1550 itx->itx_lr.lrc_seq = 0; /* defensive */ 1551 itx->itx_sync = B_TRUE; /* default is synchronous */ 1552 1553 return (itx); 1554} 1555 1556void 1557zil_itx_destroy(itx_t *itx) 1558{ 1559 kmem_free(itx, offsetof(itx_t, itx_lr) + itx->itx_lr.lrc_reclen); 1560} 1561 1562/* 1563 * Free up the sync and async itxs. The itxs_t has already been detached 1564 * so no locks are needed. 1565 */ 1566static void 1567zil_itxg_clean(itxs_t *itxs) 1568{ 1569 itx_t *itx; 1570 list_t *list; 1571 avl_tree_t *t; 1572 void *cookie; 1573 itx_async_node_t *ian; 1574 1575 list = &itxs->i_sync_list; 1576 while ((itx = list_head(list)) != NULL) { 1577 /* 1578 * In the general case, commit itxs will not be found 1579 * here, as they'll be committed to an lwb via 1580 * zil_lwb_commit(), and free'd in that function. Having 1581 * said that, it is still possible for commit itxs to be 1582 * found here, due to the following race: 1583 * 1584 * - a thread calls zil_commit() which assigns the 1585 * commit itx to a per-txg i_sync_list 1586 * - zil_itxg_clean() is called (e.g. via spa_sync()) 1587 * while the waiter is still on the i_sync_list 1588 * 1589 * There's nothing to prevent syncing the txg while the 1590 * waiter is on the i_sync_list. This normally doesn't 1591 * happen because spa_sync() is slower than zil_commit(), 1592 * but if zil_commit() calls txg_wait_synced() (e.g. 1593 * because zil_create() or zil_commit_writer_stall() is 1594 * called) we will hit this case. 1595 */ 1596 if (itx->itx_lr.lrc_txtype == TX_COMMIT) 1597 zil_commit_waiter_skip(itx->itx_private); 1598 1599 list_remove(list, itx); 1600 zil_itx_destroy(itx); 1601 } 1602 1603 cookie = NULL; 1604 t = &itxs->i_async_tree; 1605 while ((ian = avl_destroy_nodes(t, &cookie)) != NULL) { 1606 list = &ian->ia_list; 1607 while ((itx = list_head(list)) != NULL) { 1608 list_remove(list, itx); 1609 /* commit itxs should never be on the async lists. */ 1610 ASSERT3U(itx->itx_lr.lrc_txtype, !=, TX_COMMIT); 1611 zil_itx_destroy(itx); 1612 } 1613 list_destroy(list); 1614 kmem_free(ian, sizeof (itx_async_node_t)); 1615 } 1616 avl_destroy(t); 1617 1618 kmem_free(itxs, sizeof (itxs_t)); 1619} 1620 1621static int 1622zil_aitx_compare(const void *x1, const void *x2) 1623{ 1624 const uint64_t o1 = ((itx_async_node_t *)x1)->ia_foid; 1625 const uint64_t o2 = ((itx_async_node_t *)x2)->ia_foid; 1626 1627 if (o1 < o2) 1628 return (-1); 1629 if (o1 > o2) 1630 return (1); 1631 1632 return (0); 1633} 1634 1635/* 1636 * Remove all async itx with the given oid. 1637 */ 1638static void 1639zil_remove_async(zilog_t *zilog, uint64_t oid) 1640{ 1641 uint64_t otxg, txg; 1642 itx_async_node_t *ian; 1643 avl_tree_t *t; 1644 avl_index_t where; 1645 list_t clean_list; 1646 itx_t *itx; 1647 1648 ASSERT(oid != 0); 1649 list_create(&clean_list, sizeof (itx_t), offsetof(itx_t, itx_node)); 1650 1651 if (spa_freeze_txg(zilog->zl_spa) != UINT64_MAX) /* ziltest support */ 1652 otxg = ZILTEST_TXG; 1653 else 1654 otxg = spa_last_synced_txg(zilog->zl_spa) + 1; 1655 1656 for (txg = otxg; txg < (otxg + TXG_CONCURRENT_STATES); txg++) { 1657 itxg_t *itxg = &zilog->zl_itxg[txg & TXG_MASK]; 1658 1659 mutex_enter(&itxg->itxg_lock); 1660 if (itxg->itxg_txg != txg) { 1661 mutex_exit(&itxg->itxg_lock); 1662 continue; 1663 } 1664 1665 /* 1666 * Locate the object node and append its list. 1667 */ 1668 t = &itxg->itxg_itxs->i_async_tree; 1669 ian = avl_find(t, &oid, &where); 1670 if (ian != NULL) 1671 list_move_tail(&clean_list, &ian->ia_list); 1672 mutex_exit(&itxg->itxg_lock); 1673 } 1674 while ((itx = list_head(&clean_list)) != NULL) { 1675 list_remove(&clean_list, itx); 1676 /* commit itxs should never be on the async lists. */ 1677 ASSERT3U(itx->itx_lr.lrc_txtype, !=, TX_COMMIT); 1678 zil_itx_destroy(itx); 1679 } 1680 list_destroy(&clean_list); 1681} 1682 1683void 1684zil_itx_assign(zilog_t *zilog, itx_t *itx, dmu_tx_t *tx) 1685{ 1686 uint64_t txg; 1687 itxg_t *itxg; 1688 itxs_t *itxs, *clean = NULL; 1689 1690 /* 1691 * Object ids can be re-instantiated in the next txg so 1692 * remove any async transactions to avoid future leaks. 1693 * This can happen if a fsync occurs on the re-instantiated 1694 * object for a WR_INDIRECT or WR_NEED_COPY write, which gets 1695 * the new file data and flushes a write record for the old object. 1696 */ 1697 if ((itx->itx_lr.lrc_txtype & ~TX_CI) == TX_REMOVE) 1698 zil_remove_async(zilog, itx->itx_oid); 1699 1700 /* 1701 * Ensure the data of a renamed file is committed before the rename. 1702 */ 1703 if ((itx->itx_lr.lrc_txtype & ~TX_CI) == TX_RENAME) 1704 zil_async_to_sync(zilog, itx->itx_oid); 1705 1706 if (spa_freeze_txg(zilog->zl_spa) != UINT64_MAX) 1707 txg = ZILTEST_TXG; 1708 else 1709 txg = dmu_tx_get_txg(tx); 1710 1711 itxg = &zilog->zl_itxg[txg & TXG_MASK]; 1712 mutex_enter(&itxg->itxg_lock); 1713 itxs = itxg->itxg_itxs; 1714 if (itxg->itxg_txg != txg) { 1715 if (itxs != NULL) { 1716 /* 1717 * The zil_clean callback hasn't got around to cleaning 1718 * this itxg. Save the itxs for release below. 1719 * This should be rare. 1720 */ 1721 zfs_dbgmsg("zil_itx_assign: missed itx cleanup for " 1722 "txg %llu", itxg->itxg_txg); 1723 clean = itxg->itxg_itxs; 1724 } 1725 itxg->itxg_txg = txg; 1726 itxs = itxg->itxg_itxs = kmem_zalloc(sizeof (itxs_t), KM_SLEEP); 1727 1728 list_create(&itxs->i_sync_list, sizeof (itx_t), 1729 offsetof(itx_t, itx_node)); 1730 avl_create(&itxs->i_async_tree, zil_aitx_compare, 1731 sizeof (itx_async_node_t), 1732 offsetof(itx_async_node_t, ia_node)); 1733 } 1734 if (itx->itx_sync) { 1735 list_insert_tail(&itxs->i_sync_list, itx); 1736 } else { 1737 avl_tree_t *t = &itxs->i_async_tree; 1738 uint64_t foid = ((lr_ooo_t *)&itx->itx_lr)->lr_foid; 1739 itx_async_node_t *ian; 1740 avl_index_t where; 1741 1742 ian = avl_find(t, &foid, &where); 1743 if (ian == NULL) { 1744 ian = kmem_alloc(sizeof (itx_async_node_t), KM_SLEEP); 1745 list_create(&ian->ia_list, sizeof (itx_t), 1746 offsetof(itx_t, itx_node)); 1747 ian->ia_foid = foid; 1748 avl_insert(t, ian, where); 1749 } 1750 list_insert_tail(&ian->ia_list, itx); 1751 } 1752 1753 itx->itx_lr.lrc_txg = dmu_tx_get_txg(tx); 1754 1755 /* 1756 * We don't want to dirty the ZIL using ZILTEST_TXG, because 1757 * zil_clean() will never be called using ZILTEST_TXG. Thus, we 1758 * need to be careful to always dirty the ZIL using the "real" 1759 * TXG (not itxg_txg) even when the SPA is frozen. 1760 */ 1761 zilog_dirty(zilog, dmu_tx_get_txg(tx)); 1762 mutex_exit(&itxg->itxg_lock); 1763 1764 /* Release the old itxs now we've dropped the lock */ 1765 if (clean != NULL) 1766 zil_itxg_clean(clean); 1767} 1768 1769/* 1770 * If there are any in-memory intent log transactions which have now been 1771 * synced then start up a taskq to free them. We should only do this after we 1772 * have written out the uberblocks (i.e. txg has been comitted) so that 1773 * don't inadvertently clean out in-memory log records that would be required 1774 * by zil_commit(). 1775 */ 1776void 1777zil_clean(zilog_t *zilog, uint64_t synced_txg) 1778{ 1779 itxg_t *itxg = &zilog->zl_itxg[synced_txg & TXG_MASK]; 1780 itxs_t *clean_me; 1781 1782 ASSERT3U(synced_txg, <, ZILTEST_TXG); 1783 1784 mutex_enter(&itxg->itxg_lock); 1785 if (itxg->itxg_itxs == NULL || itxg->itxg_txg == ZILTEST_TXG) { 1786 mutex_exit(&itxg->itxg_lock); 1787 return; 1788 } 1789 ASSERT3U(itxg->itxg_txg, <=, synced_txg); 1790 ASSERT3U(itxg->itxg_txg, !=, 0); 1791 clean_me = itxg->itxg_itxs; 1792 itxg->itxg_itxs = NULL; 1793 itxg->itxg_txg = 0; 1794 mutex_exit(&itxg->itxg_lock); 1795 /* 1796 * Preferably start a task queue to free up the old itxs but 1797 * if taskq_dispatch can't allocate resources to do that then 1798 * free it in-line. This should be rare. Note, using TQ_SLEEP 1799 * created a bad performance problem. 1800 */ 1801 ASSERT3P(zilog->zl_dmu_pool, !=, NULL); 1802 ASSERT3P(zilog->zl_dmu_pool->dp_zil_clean_taskq, !=, NULL); 1803 if (taskq_dispatch(zilog->zl_dmu_pool->dp_zil_clean_taskq, 1804 (void (*)(void *))zil_itxg_clean, clean_me, TQ_NOSLEEP) == 0) 1805 zil_itxg_clean(clean_me); 1806} 1807 1808/* 1809 * This function will traverse the queue of itxs that need to be 1810 * committed, and move them onto the ZIL's zl_itx_commit_list. 1811 */ 1812static void 1813zil_get_commit_list(zilog_t *zilog) 1814{ 1815 uint64_t otxg, txg; 1816 list_t *commit_list = &zilog->zl_itx_commit_list; 1817 1818 ASSERT(MUTEX_HELD(&zilog->zl_issuer_lock)); 1819 1820 if (spa_freeze_txg(zilog->zl_spa) != UINT64_MAX) /* ziltest support */ 1821 otxg = ZILTEST_TXG; 1822 else 1823 otxg = spa_last_synced_txg(zilog->zl_spa) + 1; 1824 1825 /* 1826 * This is inherently racy, since there is nothing to prevent 1827 * the last synced txg from changing. That's okay since we'll 1828 * only commit things in the future. 1829 */ 1830 for (txg = otxg; txg < (otxg + TXG_CONCURRENT_STATES); txg++) { 1831 itxg_t *itxg = &zilog->zl_itxg[txg & TXG_MASK]; 1832 1833 mutex_enter(&itxg->itxg_lock); 1834 if (itxg->itxg_txg != txg) { 1835 mutex_exit(&itxg->itxg_lock); 1836 continue; 1837 } 1838 1839 /* 1840 * If we're adding itx records to the zl_itx_commit_list, 1841 * then the zil better be dirty in this "txg". We can assert 1842 * that here since we're holding the itxg_lock which will 1843 * prevent spa_sync from cleaning it. Once we add the itxs 1844 * to the zl_itx_commit_list we must commit it to disk even 1845 * if it's unnecessary (i.e. the txg was synced). 1846 */ 1847 ASSERT(zilog_is_dirty_in_txg(zilog, txg) || 1848 spa_freeze_txg(zilog->zl_spa) != UINT64_MAX); 1849 list_move_tail(commit_list, &itxg->itxg_itxs->i_sync_list); 1850 1851 mutex_exit(&itxg->itxg_lock); 1852 } 1853} 1854 1855/* 1856 * Move the async itxs for a specified object to commit into sync lists. 1857 */ 1858void 1859zil_async_to_sync(zilog_t *zilog, uint64_t foid) 1860{ 1861 uint64_t otxg, txg; 1862 itx_async_node_t *ian; 1863 avl_tree_t *t; 1864 avl_index_t where; 1865 1866 if (spa_freeze_txg(zilog->zl_spa) != UINT64_MAX) /* ziltest support */ 1867 otxg = ZILTEST_TXG; 1868 else 1869 otxg = spa_last_synced_txg(zilog->zl_spa) + 1; 1870 1871 /* 1872 * This is inherently racy, since there is nothing to prevent 1873 * the last synced txg from changing. 1874 */ 1875 for (txg = otxg; txg < (otxg + TXG_CONCURRENT_STATES); txg++) { 1876 itxg_t *itxg = &zilog->zl_itxg[txg & TXG_MASK]; 1877 1878 mutex_enter(&itxg->itxg_lock); 1879 if (itxg->itxg_txg != txg) { 1880 mutex_exit(&itxg->itxg_lock); 1881 continue; 1882 } 1883 1884 /* 1885 * If a foid is specified then find that node and append its 1886 * list. Otherwise walk the tree appending all the lists 1887 * to the sync list. We add to the end rather than the 1888 * beginning to ensure the create has happened. 1889 */ 1890 t = &itxg->itxg_itxs->i_async_tree; 1891 if (foid != 0) { 1892 ian = avl_find(t, &foid, &where); 1893 if (ian != NULL) { 1894 list_move_tail(&itxg->itxg_itxs->i_sync_list, 1895 &ian->ia_list); 1896 } 1897 } else { 1898 void *cookie = NULL; 1899 1900 while ((ian = avl_destroy_nodes(t, &cookie)) != NULL) { 1901 list_move_tail(&itxg->itxg_itxs->i_sync_list, 1902 &ian->ia_list); 1903 list_destroy(&ian->ia_list); 1904 kmem_free(ian, sizeof (itx_async_node_t)); 1905 } 1906 } 1907 mutex_exit(&itxg->itxg_lock); 1908 } 1909} 1910 1911/* 1912 * This function will prune commit itxs that are at the head of the 1913 * commit list (it won't prune past the first non-commit itx), and 1914 * either: a) attach them to the last lwb that's still pending 1915 * completion, or b) skip them altogether. 1916 * 1917 * This is used as a performance optimization to prevent commit itxs 1918 * from generating new lwbs when it's unnecessary to do so. 1919 */ 1920static void 1921zil_prune_commit_list(zilog_t *zilog) 1922{ 1923 itx_t *itx; 1924 1925 ASSERT(MUTEX_HELD(&zilog->zl_issuer_lock)); 1926 1927 while (itx = list_head(&zilog->zl_itx_commit_list)) { 1928 lr_t *lrc = &itx->itx_lr; 1929 if (lrc->lrc_txtype != TX_COMMIT) 1930 break; 1931 1932 mutex_enter(&zilog->zl_lock); 1933 1934 lwb_t *last_lwb = zilog->zl_last_lwb_opened; 1935 if (last_lwb == NULL || last_lwb->lwb_state == LWB_STATE_DONE) { 1936 /* 1937 * All of the itxs this waiter was waiting on 1938 * must have already completed (or there were 1939 * never any itx's for it to wait on), so it's 1940 * safe to skip this waiter and mark it done. 1941 */ 1942 zil_commit_waiter_skip(itx->itx_private); 1943 } else { 1944 zil_commit_waiter_link_lwb(itx->itx_private, last_lwb); 1945 itx->itx_private = NULL; 1946 } 1947 1948 mutex_exit(&zilog->zl_lock); 1949 1950 list_remove(&zilog->zl_itx_commit_list, itx); 1951 zil_itx_destroy(itx); 1952 } 1953 1954 IMPLY(itx != NULL, itx->itx_lr.lrc_txtype != TX_COMMIT); 1955} 1956 1957static void 1958zil_commit_writer_stall(zilog_t *zilog) 1959{ 1960 /* 1961 * When zio_alloc_zil() fails to allocate the next lwb block on 1962 * disk, we must call txg_wait_synced() to ensure all of the 1963 * lwbs in the zilog's zl_lwb_list are synced and then freed (in 1964 * zil_sync()), such that any subsequent ZIL writer (i.e. a call 1965 * to zil_process_commit_list()) will have to call zil_create(), 1966 * and start a new ZIL chain. 1967 * 1968 * Since zil_alloc_zil() failed, the lwb that was previously 1969 * issued does not have a pointer to the "next" lwb on disk. 1970 * Thus, if another ZIL writer thread was to allocate the "next" 1971 * on-disk lwb, that block could be leaked in the event of a 1972 * crash (because the previous lwb on-disk would not point to 1973 * it). 1974 * 1975 * We must hold the zilog's zl_issuer_lock while we do this, to 1976 * ensure no new threads enter zil_process_commit_list() until 1977 * all lwb's in the zl_lwb_list have been synced and freed 1978 * (which is achieved via the txg_wait_synced() call). 1979 */ 1980 ASSERT(MUTEX_HELD(&zilog->zl_issuer_lock)); 1981 txg_wait_synced(zilog->zl_dmu_pool, 0); 1982 ASSERT3P(list_tail(&zilog->zl_lwb_list), ==, NULL); 1983} 1984 1985/* 1986 * This function will traverse the commit list, creating new lwbs as 1987 * needed, and committing the itxs from the commit list to these newly 1988 * created lwbs. Additionally, as a new lwb is created, the previous 1989 * lwb will be issued to the zio layer to be written to disk. 1990 */ 1991static void 1992zil_process_commit_list(zilog_t *zilog) 1993{ 1994 spa_t *spa = zilog->zl_spa; 1995 list_t nolwb_waiters; 1996 lwb_t *lwb; 1997 itx_t *itx; 1998 1999 ASSERT(MUTEX_HELD(&zilog->zl_issuer_lock)); 2000 2001 /* 2002 * Return if there's nothing to commit before we dirty the fs by 2003 * calling zil_create(). 2004 */ 2005 if (list_head(&zilog->zl_itx_commit_list) == NULL) 2006 return; 2007 2008 list_create(&nolwb_waiters, sizeof (zil_commit_waiter_t), 2009 offsetof(zil_commit_waiter_t, zcw_node)); 2010 2011 lwb = list_tail(&zilog->zl_lwb_list); 2012 if (lwb == NULL) { 2013 lwb = zil_create(zilog); 2014 } else { 2015 ASSERT3S(lwb->lwb_state, !=, LWB_STATE_ISSUED); 2016 ASSERT3S(lwb->lwb_state, !=, LWB_STATE_DONE); 2017 } 2018 2019 while (itx = list_head(&zilog->zl_itx_commit_list)) { 2020 lr_t *lrc = &itx->itx_lr; 2021 uint64_t txg = lrc->lrc_txg; 2022 2023 ASSERT3U(txg, !=, 0); 2024 2025 if (lrc->lrc_txtype == TX_COMMIT) { 2026 DTRACE_PROBE2(zil__process__commit__itx, 2027 zilog_t *, zilog, itx_t *, itx); 2028 } else { 2029 DTRACE_PROBE2(zil__process__normal__itx, 2030 zilog_t *, zilog, itx_t *, itx); 2031 } 2032 2033 boolean_t synced = txg <= spa_last_synced_txg(spa); 2034 boolean_t frozen = txg > spa_freeze_txg(spa); 2035 2036 /* 2037 * If the txg of this itx has already been synced out, then 2038 * we don't need to commit this itx to an lwb. This is 2039 * because the data of this itx will have already been 2040 * written to the main pool. This is inherently racy, and 2041 * it's still ok to commit an itx whose txg has already 2042 * been synced; this will result in a write that's 2043 * unnecessary, but will do no harm. 2044 * 2045 * With that said, we always want to commit TX_COMMIT itxs 2046 * to an lwb, regardless of whether or not that itx's txg 2047 * has been synced out. We do this to ensure any OPENED lwb 2048 * will always have at least one zil_commit_waiter_t linked 2049 * to the lwb. 2050 * 2051 * As a counter-example, if we skipped TX_COMMIT itx's 2052 * whose txg had already been synced, the following 2053 * situation could occur if we happened to be racing with 2054 * spa_sync: 2055 * 2056 * 1. we commit a non-TX_COMMIT itx to an lwb, where the 2057 * itx's txg is 10 and the last synced txg is 9. 2058 * 2. spa_sync finishes syncing out txg 10. 2059 * 3. we move to the next itx in the list, it's a TX_COMMIT 2060 * whose txg is 10, so we skip it rather than committing 2061 * it to the lwb used in (1). 2062 * 2063 * If the itx that is skipped in (3) is the last TX_COMMIT 2064 * itx in the commit list, than it's possible for the lwb 2065 * used in (1) to remain in the OPENED state indefinitely. 2066 * 2067 * To prevent the above scenario from occuring, ensuring 2068 * that once an lwb is OPENED it will transition to ISSUED 2069 * and eventually DONE, we always commit TX_COMMIT itx's to 2070 * an lwb here, even if that itx's txg has already been 2071 * synced. 2072 * 2073 * Finally, if the pool is frozen, we _always_ commit the 2074 * itx. The point of freezing the pool is to prevent data 2075 * from being written to the main pool via spa_sync, and 2076 * instead rely solely on the ZIL to persistently store the 2077 * data; i.e. when the pool is frozen, the last synced txg 2078 * value can't be trusted. 2079 */ 2080 if (frozen || !synced || lrc->lrc_txtype == TX_COMMIT) { 2081 if (lwb != NULL) { 2082 lwb = zil_lwb_commit(zilog, itx, lwb); 2083 } else if (lrc->lrc_txtype == TX_COMMIT) { 2084 ASSERT3P(lwb, ==, NULL); 2085 zil_commit_waiter_link_nolwb( 2086 itx->itx_private, &nolwb_waiters); 2087 } 2088 } 2089 2090 list_remove(&zilog->zl_itx_commit_list, itx); 2091 zil_itx_destroy(itx); 2092 } 2093 2094 if (lwb == NULL) { 2095 /* 2096 * This indicates zio_alloc_zil() failed to allocate the 2097 * "next" lwb on-disk. When this happens, we must stall 2098 * the ZIL write pipeline; see the comment within 2099 * zil_commit_writer_stall() for more details. 2100 */ 2101 zil_commit_writer_stall(zilog); 2102 2103 /* 2104 * Additionally, we have to signal and mark the "nolwb" 2105 * waiters as "done" here, since without an lwb, we 2106 * can't do this via zil_lwb_flush_vdevs_done() like 2107 * normal. 2108 */ 2109 zil_commit_waiter_t *zcw; 2110 while (zcw = list_head(&nolwb_waiters)) { 2111 zil_commit_waiter_skip(zcw); 2112 list_remove(&nolwb_waiters, zcw); 2113 } 2114 } else { 2115 ASSERT(list_is_empty(&nolwb_waiters)); 2116 ASSERT3P(lwb, !=, NULL); 2117 ASSERT3S(lwb->lwb_state, !=, LWB_STATE_ISSUED); 2118 ASSERT3S(lwb->lwb_state, !=, LWB_STATE_DONE); 2119 2120 /* 2121 * At this point, the ZIL block pointed at by the "lwb" 2122 * variable is in one of the following states: "closed" 2123 * or "open". 2124 * 2125 * If its "closed", then no itxs have been committed to 2126 * it, so there's no point in issuing its zio (i.e. 2127 * it's "empty"). 2128 * 2129 * If its "open" state, then it contains one or more 2130 * itxs that eventually need to be committed to stable 2131 * storage. In this case we intentionally do not issue 2132 * the lwb's zio to disk yet, and instead rely on one of 2133 * the following two mechanisms for issuing the zio: 2134 * 2135 * 1. Ideally, there will be more ZIL activity occuring 2136 * on the system, such that this function will be 2137 * immediately called again (not necessarily by the same 2138 * thread) and this lwb's zio will be issued via 2139 * zil_lwb_commit(). This way, the lwb is guaranteed to 2140 * be "full" when it is issued to disk, and we'll make 2141 * use of the lwb's size the best we can. 2142 * 2143 * 2. If there isn't sufficient ZIL activity occuring on 2144 * the system, such that this lwb's zio isn't issued via 2145 * zil_lwb_commit(), zil_commit_waiter() will issue the 2146 * lwb's zio. If this occurs, the lwb is not guaranteed 2147 * to be "full" by the time its zio is issued, and means 2148 * the size of the lwb was "too large" given the amount 2149 * of ZIL activity occuring on the system at that time. 2150 * 2151 * We do this for a couple of reasons: 2152 * 2153 * 1. To try and reduce the number of IOPs needed to 2154 * write the same number of itxs. If an lwb has space 2155 * available in it's buffer for more itxs, and more itxs 2156 * will be committed relatively soon (relative to the 2157 * latency of performing a write), then it's beneficial 2158 * to wait for these "next" itxs. This way, more itxs 2159 * can be committed to stable storage with fewer writes. 2160 * 2161 * 2. To try and use the largest lwb block size that the 2162 * incoming rate of itxs can support. Again, this is to 2163 * try and pack as many itxs into as few lwbs as 2164 * possible, without significantly impacting the latency 2165 * of each individual itx. 2166 */ 2167 } 2168} 2169 2170/* 2171 * This function is responsible for ensuring the passed in commit waiter 2172 * (and associated commit itx) is committed to an lwb. If the waiter is 2173 * not already committed to an lwb, all itxs in the zilog's queue of 2174 * itxs will be processed. The assumption is the passed in waiter's 2175 * commit itx will found in the queue just like the other non-commit 2176 * itxs, such that when the entire queue is processed, the waiter will 2177 * have been commited to an lwb. 2178 * 2179 * The lwb associated with the passed in waiter is not guaranteed to 2180 * have been issued by the time this function completes. If the lwb is 2181 * not issued, we rely on future calls to zil_commit_writer() to issue 2182 * the lwb, or the timeout mechanism found in zil_commit_waiter(). 2183 */ 2184static void 2185zil_commit_writer(zilog_t *zilog, zil_commit_waiter_t *zcw) 2186{ 2187 ASSERT(!MUTEX_HELD(&zilog->zl_lock)); 2188 ASSERT(spa_writeable(zilog->zl_spa)); 2189 2190 mutex_enter(&zilog->zl_issuer_lock); 2191 2192 if (zcw->zcw_lwb != NULL || zcw->zcw_done) { 2193 /* 2194 * It's possible that, while we were waiting to acquire 2195 * the "zl_issuer_lock", another thread committed this 2196 * waiter to an lwb. If that occurs, we bail out early, 2197 * without processing any of the zilog's queue of itxs. 2198 * 2199 * On certain workloads and system configurations, the 2200 * "zl_issuer_lock" can become highly contended. In an 2201 * attempt to reduce this contention, we immediately drop 2202 * the lock if the waiter has already been processed. 2203 * 2204 * We've measured this optimization to reduce CPU spent 2205 * contending on this lock by up to 5%, using a system 2206 * with 32 CPUs, low latency storage (~50 usec writes), 2207 * and 1024 threads performing sync writes. 2208 */ 2209 goto out; 2210 } 2211 2212 zil_get_commit_list(zilog); 2213 zil_prune_commit_list(zilog); 2214 zil_process_commit_list(zilog); 2215 2216out: 2217 mutex_exit(&zilog->zl_issuer_lock); 2218} 2219 2220static void 2221zil_commit_waiter_timeout(zilog_t *zilog, zil_commit_waiter_t *zcw) 2222{ 2223 ASSERT(!MUTEX_HELD(&zilog->zl_issuer_lock)); 2224 ASSERT(MUTEX_HELD(&zcw->zcw_lock)); 2225 ASSERT3B(zcw->zcw_done, ==, B_FALSE); 2226 2227 lwb_t *lwb = zcw->zcw_lwb; 2228 ASSERT3P(lwb, !=, NULL); 2229 ASSERT3S(lwb->lwb_state, !=, LWB_STATE_CLOSED); 2230 2231 /* 2232 * If the lwb has already been issued by another thread, we can 2233 * immediately return since there's no work to be done (the 2234 * point of this function is to issue the lwb). Additionally, we 2235 * do this prior to acquiring the zl_issuer_lock, to avoid 2236 * acquiring it when it's not necessary to do so. 2237 */ 2238 if (lwb->lwb_state == LWB_STATE_ISSUED || 2239 lwb->lwb_state == LWB_STATE_DONE) 2240 return; 2241 2242 /* 2243 * In order to call zil_lwb_write_issue() we must hold the 2244 * zilog's "zl_issuer_lock". We can't simply acquire that lock, 2245 * since we're already holding the commit waiter's "zcw_lock", 2246 * and those two locks are aquired in the opposite order 2247 * elsewhere. 2248 */ 2249 mutex_exit(&zcw->zcw_lock); 2250 mutex_enter(&zilog->zl_issuer_lock); 2251 mutex_enter(&zcw->zcw_lock); 2252 2253 /* 2254 * Since we just dropped and re-acquired the commit waiter's 2255 * lock, we have to re-check to see if the waiter was marked 2256 * "done" during that process. If the waiter was marked "done", 2257 * the "lwb" pointer is no longer valid (it can be free'd after 2258 * the waiter is marked "done"), so without this check we could 2259 * wind up with a use-after-free error below. 2260 */ 2261 if (zcw->zcw_done) 2262 goto out; 2263 2264 ASSERT3P(lwb, ==, zcw->zcw_lwb); 2265 2266 /* 2267 * We've already checked this above, but since we hadn't acquired 2268 * the zilog's zl_issuer_lock, we have to perform this check a 2269 * second time while holding the lock. 2270 * 2271 * We don't need to hold the zl_lock since the lwb cannot transition 2272 * from OPENED to ISSUED while we hold the zl_issuer_lock. The lwb 2273 * _can_ transition from ISSUED to DONE, but it's OK to race with 2274 * that transition since we treat the lwb the same, whether it's in 2275 * the ISSUED or DONE states. 2276 * 2277 * The important thing, is we treat the lwb differently depending on 2278 * if it's ISSUED or OPENED, and block any other threads that might 2279 * attempt to issue this lwb. For that reason we hold the 2280 * zl_issuer_lock when checking the lwb_state; we must not call 2281 * zil_lwb_write_issue() if the lwb had already been issued. 2282 * 2283 * See the comment above the lwb_state_t structure definition for 2284 * more details on the lwb states, and locking requirements. 2285 */ 2286 if (lwb->lwb_state == LWB_STATE_ISSUED || 2287 lwb->lwb_state == LWB_STATE_DONE) 2288 goto out; 2289 2290 ASSERT3S(lwb->lwb_state, ==, LWB_STATE_OPENED); 2291 2292 /* 2293 * As described in the comments above zil_commit_waiter() and 2294 * zil_process_commit_list(), we need to issue this lwb's zio 2295 * since we've reached the commit waiter's timeout and it still 2296 * hasn't been issued. 2297 */ 2298 lwb_t *nlwb = zil_lwb_write_issue(zilog, lwb); 2299 2300 ASSERT3S(lwb->lwb_state, !=, LWB_STATE_OPENED); 2301 2302 /* 2303 * Since the lwb's zio hadn't been issued by the time this thread 2304 * reached its timeout, we reset the zilog's "zl_cur_used" field 2305 * to influence the zil block size selection algorithm. 2306 * 2307 * By having to issue the lwb's zio here, it means the size of the 2308 * lwb was too large, given the incoming throughput of itxs. By 2309 * setting "zl_cur_used" to zero, we communicate this fact to the 2310 * block size selection algorithm, so it can take this informaiton 2311 * into account, and potentially select a smaller size for the 2312 * next lwb block that is allocated. 2313 */ 2314 zilog->zl_cur_used = 0; 2315 2316 if (nlwb == NULL) { 2317 /* 2318 * When zil_lwb_write_issue() returns NULL, this 2319 * indicates zio_alloc_zil() failed to allocate the 2320 * "next" lwb on-disk. When this occurs, the ZIL write 2321 * pipeline must be stalled; see the comment within the 2322 * zil_commit_writer_stall() function for more details. 2323 * 2324 * We must drop the commit waiter's lock prior to 2325 * calling zil_commit_writer_stall() or else we can wind 2326 * up with the following deadlock: 2327 * 2328 * - This thread is waiting for the txg to sync while 2329 * holding the waiter's lock; txg_wait_synced() is 2330 * used within txg_commit_writer_stall(). 2331 * 2332 * - The txg can't sync because it is waiting for this 2333 * lwb's zio callback to call dmu_tx_commit(). 2334 * 2335 * - The lwb's zio callback can't call dmu_tx_commit() 2336 * because it's blocked trying to acquire the waiter's 2337 * lock, which occurs prior to calling dmu_tx_commit() 2338 */ 2339 mutex_exit(&zcw->zcw_lock); 2340 zil_commit_writer_stall(zilog); 2341 mutex_enter(&zcw->zcw_lock); 2342 } 2343 2344out: 2345 mutex_exit(&zilog->zl_issuer_lock); 2346 ASSERT(MUTEX_HELD(&zcw->zcw_lock)); 2347} 2348 2349/* 2350 * This function is responsible for performing the following two tasks: 2351 * 2352 * 1. its primary responsibility is to block until the given "commit 2353 * waiter" is considered "done". 2354 * 2355 * 2. its secondary responsibility is to issue the zio for the lwb that 2356 * the given "commit waiter" is waiting on, if this function has 2357 * waited "long enough" and the lwb is still in the "open" state. 2358 * 2359 * Given a sufficient amount of itxs being generated and written using 2360 * the ZIL, the lwb's zio will be issued via the zil_lwb_commit() 2361 * function. If this does not occur, this secondary responsibility will 2362 * ensure the lwb is issued even if there is not other synchronous 2363 * activity on the system. 2364 * 2365 * For more details, see zil_process_commit_list(); more specifically, 2366 * the comment at the bottom of that function. 2367 */ 2368static void 2369zil_commit_waiter(zilog_t *zilog, zil_commit_waiter_t *zcw) 2370{ 2371 ASSERT(!MUTEX_HELD(&zilog->zl_lock)); 2372 ASSERT(!MUTEX_HELD(&zilog->zl_issuer_lock)); 2373 ASSERT(spa_writeable(zilog->zl_spa)); 2374 2375 mutex_enter(&zcw->zcw_lock); 2376 2377 /* 2378 * The timeout is scaled based on the lwb latency to avoid 2379 * significantly impacting the latency of each individual itx. 2380 * For more details, see the comment at the bottom of the 2381 * zil_process_commit_list() function. 2382 */ 2383 int pct = MAX(zfs_commit_timeout_pct, 1); 2384#if defined(illumos) || !defined(_KERNEL) 2385 hrtime_t sleep = (zilog->zl_last_lwb_latency * pct) / 100; 2386 hrtime_t wakeup = gethrtime() + sleep; 2387#else 2388 sbintime_t sleep = nstosbt((zilog->zl_last_lwb_latency * pct) / 100); 2389 sbintime_t wakeup = getsbinuptime() + sleep; 2390#endif 2391 boolean_t timedout = B_FALSE; 2392 2393 while (!zcw->zcw_done) { 2394 ASSERT(MUTEX_HELD(&zcw->zcw_lock)); 2395 2396 lwb_t *lwb = zcw->zcw_lwb; 2397 2398 /* 2399 * Usually, the waiter will have a non-NULL lwb field here, 2400 * but it's possible for it to be NULL as a result of 2401 * zil_commit() racing with spa_sync(). 2402 * 2403 * When zil_clean() is called, it's possible for the itxg 2404 * list (which may be cleaned via a taskq) to contain 2405 * commit itxs. When this occurs, the commit waiters linked 2406 * off of these commit itxs will not be committed to an 2407 * lwb. Additionally, these commit waiters will not be 2408 * marked done until zil_commit_waiter_skip() is called via 2409 * zil_itxg_clean(). 2410 * 2411 * Thus, it's possible for this commit waiter (i.e. the 2412 * "zcw" variable) to be found in this "in between" state; 2413 * where it's "zcw_lwb" field is NULL, and it hasn't yet 2414 * been skipped, so it's "zcw_done" field is still B_FALSE. 2415 */ 2416 IMPLY(lwb != NULL, lwb->lwb_state != LWB_STATE_CLOSED); 2417 2418 if (lwb != NULL && lwb->lwb_state == LWB_STATE_OPENED) { 2419 ASSERT3B(timedout, ==, B_FALSE); 2420 2421 /* 2422 * If the lwb hasn't been issued yet, then we 2423 * need to wait with a timeout, in case this 2424 * function needs to issue the lwb after the 2425 * timeout is reached; responsibility (2) from 2426 * the comment above this function. 2427 */ 2428#if defined(illumos) || !defined(_KERNEL) 2429 clock_t timeleft = cv_timedwait_hires(&zcw->zcw_cv, 2430 &zcw->zcw_lock, wakeup, USEC2NSEC(1), 2431 CALLOUT_FLAG_ABSOLUTE); 2432 2433 if (timeleft >= 0 || zcw->zcw_done) 2434 continue; 2435#else 2436 int wait_err = cv_timedwait_sbt(&zcw->zcw_cv, 2437 &zcw->zcw_lock, wakeup, SBT_1NS, C_ABSOLUTE); 2438 if (wait_err != EWOULDBLOCK || zcw->zcw_done) 2439 continue; 2440#endif 2441 2442 timedout = B_TRUE; 2443 zil_commit_waiter_timeout(zilog, zcw); 2444 2445 if (!zcw->zcw_done) { 2446 /* 2447 * If the commit waiter has already been 2448 * marked "done", it's possible for the 2449 * waiter's lwb structure to have already 2450 * been freed. Thus, we can only reliably 2451 * make these assertions if the waiter 2452 * isn't done. 2453 */ 2454 ASSERT3P(lwb, ==, zcw->zcw_lwb); 2455 ASSERT3S(lwb->lwb_state, !=, LWB_STATE_OPENED); 2456 } 2457 } else { 2458 /* 2459 * If the lwb isn't open, then it must have already 2460 * been issued. In that case, there's no need to 2461 * use a timeout when waiting for the lwb to 2462 * complete. 2463 * 2464 * Additionally, if the lwb is NULL, the waiter 2465 * will soon be signalled and marked done via 2466 * zil_clean() and zil_itxg_clean(), so no timeout 2467 * is required. 2468 */ 2469 2470 IMPLY(lwb != NULL, 2471 lwb->lwb_state == LWB_STATE_ISSUED || 2472 lwb->lwb_state == LWB_STATE_DONE); 2473 cv_wait(&zcw->zcw_cv, &zcw->zcw_lock); 2474 } 2475 } 2476 2477 mutex_exit(&zcw->zcw_lock); 2478} 2479 2480static zil_commit_waiter_t * 2481zil_alloc_commit_waiter() 2482{ 2483 zil_commit_waiter_t *zcw = kmem_cache_alloc(zil_zcw_cache, KM_SLEEP); 2484 2485 cv_init(&zcw->zcw_cv, NULL, CV_DEFAULT, NULL); 2486 mutex_init(&zcw->zcw_lock, NULL, MUTEX_DEFAULT, NULL); 2487 list_link_init(&zcw->zcw_node); 2488 zcw->zcw_lwb = NULL; 2489 zcw->zcw_done = B_FALSE; 2490 zcw->zcw_zio_error = 0; 2491 2492 return (zcw); 2493} 2494 2495static void 2496zil_free_commit_waiter(zil_commit_waiter_t *zcw) 2497{ 2498 ASSERT(!list_link_active(&zcw->zcw_node)); 2499 ASSERT3P(zcw->zcw_lwb, ==, NULL); 2500 ASSERT3B(zcw->zcw_done, ==, B_TRUE); 2501 mutex_destroy(&zcw->zcw_lock); 2502 cv_destroy(&zcw->zcw_cv); 2503 kmem_cache_free(zil_zcw_cache, zcw); 2504} 2505 2506/* 2507 * This function is used to create a TX_COMMIT itx and assign it. This 2508 * way, it will be linked into the ZIL's list of synchronous itxs, and 2509 * then later committed to an lwb (or skipped) when 2510 * zil_process_commit_list() is called. 2511 */ 2512static void 2513zil_commit_itx_assign(zilog_t *zilog, zil_commit_waiter_t *zcw) 2514{ 2515 dmu_tx_t *tx = dmu_tx_create(zilog->zl_os); 2516 VERIFY0(dmu_tx_assign(tx, TXG_WAIT)); 2517 2518 itx_t *itx = zil_itx_create(TX_COMMIT, sizeof (lr_t)); 2519 itx->itx_sync = B_TRUE; 2520 itx->itx_private = zcw; 2521 2522 zil_itx_assign(zilog, itx, tx); 2523 2524 dmu_tx_commit(tx); 2525} 2526 2527/* 2528 * Commit ZFS Intent Log transactions (itxs) to stable storage. 2529 * 2530 * When writing ZIL transactions to the on-disk representation of the 2531 * ZIL, the itxs are committed to a Log Write Block (lwb). Multiple 2532 * itxs can be committed to a single lwb. Once a lwb is written and 2533 * committed to stable storage (i.e. the lwb is written, and vdevs have 2534 * been flushed), each itx that was committed to that lwb is also 2535 * considered to be committed to stable storage. 2536 * 2537 * When an itx is committed to an lwb, the log record (lr_t) contained 2538 * by the itx is copied into the lwb's zio buffer, and once this buffer 2539 * is written to disk, it becomes an on-disk ZIL block. 2540 * 2541 * As itxs are generated, they're inserted into the ZIL's queue of 2542 * uncommitted itxs. The semantics of zil_commit() are such that it will 2543 * block until all itxs that were in the queue when it was called, are 2544 * committed to stable storage. 2545 * 2546 * If "foid" is zero, this means all "synchronous" and "asynchronous" 2547 * itxs, for all objects in the dataset, will be committed to stable 2548 * storage prior to zil_commit() returning. If "foid" is non-zero, all 2549 * "synchronous" itxs for all objects, but only "asynchronous" itxs 2550 * that correspond to the foid passed in, will be committed to stable 2551 * storage prior to zil_commit() returning. 2552 * 2553 * Generally speaking, when zil_commit() is called, the consumer doesn't 2554 * actually care about _all_ of the uncommitted itxs. Instead, they're 2555 * simply trying to waiting for a specific itx to be committed to disk, 2556 * but the interface(s) for interacting with the ZIL don't allow such 2557 * fine-grained communication. A better interface would allow a consumer 2558 * to create and assign an itx, and then pass a reference to this itx to 2559 * zil_commit(); such that zil_commit() would return as soon as that 2560 * specific itx was committed to disk (instead of waiting for _all_ 2561 * itxs to be committed). 2562 * 2563 * When a thread calls zil_commit() a special "commit itx" will be 2564 * generated, along with a corresponding "waiter" for this commit itx. 2565 * zil_commit() will wait on this waiter's CV, such that when the waiter 2566 * is marked done, and signalled, zil_commit() will return. 2567 * 2568 * This commit itx is inserted into the queue of uncommitted itxs. This 2569 * provides an easy mechanism for determining which itxs were in the 2570 * queue prior to zil_commit() having been called, and which itxs were 2571 * added after zil_commit() was called. 2572 * 2573 * The commit it is special; it doesn't have any on-disk representation. 2574 * When a commit itx is "committed" to an lwb, the waiter associated 2575 * with it is linked onto the lwb's list of waiters. Then, when that lwb 2576 * completes, each waiter on the lwb's list is marked done and signalled 2577 * -- allowing the thread waiting on the waiter to return from zil_commit(). 2578 * 2579 * It's important to point out a few critical factors that allow us 2580 * to make use of the commit itxs, commit waiters, per-lwb lists of 2581 * commit waiters, and zio completion callbacks like we're doing: 2582 * 2583 * 1. The list of waiters for each lwb is traversed, and each commit 2584 * waiter is marked "done" and signalled, in the zio completion 2585 * callback of the lwb's zio[*]. 2586 * 2587 * * Actually, the waiters are signalled in the zio completion 2588 * callback of the root zio for the DKIOCFLUSHWRITECACHE commands 2589 * that are sent to the vdevs upon completion of the lwb zio. 2590 * 2591 * 2. When the itxs are inserted into the ZIL's queue of uncommitted 2592 * itxs, the order in which they are inserted is preserved[*]; as 2593 * itxs are added to the queue, they are added to the tail of 2594 * in-memory linked lists. 2595 * 2596 * When committing the itxs to lwbs (to be written to disk), they 2597 * are committed in the same order in which the itxs were added to 2598 * the uncommitted queue's linked list(s); i.e. the linked list of 2599 * itxs to commit is traversed from head to tail, and each itx is 2600 * committed to an lwb in that order. 2601 * 2602 * * To clarify: 2603 * 2604 * - the order of "sync" itxs is preserved w.r.t. other 2605 * "sync" itxs, regardless of the corresponding objects. 2606 * - the order of "async" itxs is preserved w.r.t. other 2607 * "async" itxs corresponding to the same object. 2608 * - the order of "async" itxs is *not* preserved w.r.t. other 2609 * "async" itxs corresponding to different objects. 2610 * - the order of "sync" itxs w.r.t. "async" itxs (or vice 2611 * versa) is *not* preserved, even for itxs that correspond 2612 * to the same object. 2613 * 2614 * For more details, see: zil_itx_assign(), zil_async_to_sync(), 2615 * zil_get_commit_list(), and zil_process_commit_list(). 2616 * 2617 * 3. The lwbs represent a linked list of blocks on disk. Thus, any 2618 * lwb cannot be considered committed to stable storage, until its 2619 * "previous" lwb is also committed to stable storage. This fact, 2620 * coupled with the fact described above, means that itxs are 2621 * committed in (roughly) the order in which they were generated. 2622 * This is essential because itxs are dependent on prior itxs. 2623 * Thus, we *must not* deem an itx as being committed to stable 2624 * storage, until *all* prior itxs have also been committed to 2625 * stable storage. 2626 * 2627 * To enforce this ordering of lwb zio's, while still leveraging as 2628 * much of the underlying storage performance as possible, we rely 2629 * on two fundamental concepts: 2630 * 2631 * 1. The creation and issuance of lwb zio's is protected by 2632 * the zilog's "zl_issuer_lock", which ensures only a single 2633 * thread is creating and/or issuing lwb's at a time 2634 * 2. The "previous" lwb is a child of the "current" lwb 2635 * (leveraging the zio parent-child depenency graph) 2636 * 2637 * By relying on this parent-child zio relationship, we can have 2638 * many lwb zio's concurrently issued to the underlying storage, 2639 * but the order in which they complete will be the same order in 2640 * which they were created. 2641 */ 2642void 2643zil_commit(zilog_t *zilog, uint64_t foid) 2644{ 2645 /* 2646 * We should never attempt to call zil_commit on a snapshot for 2647 * a couple of reasons: 2648 * 2649 * 1. A snapshot may never be modified, thus it cannot have any 2650 * in-flight itxs that would have modified the dataset. 2651 * 2652 * 2. By design, when zil_commit() is called, a commit itx will 2653 * be assigned to this zilog; as a result, the zilog will be 2654 * dirtied. We must not dirty the zilog of a snapshot; there's 2655 * checks in the code that enforce this invariant, and will 2656 * cause a panic if it's not upheld. 2657 */ 2658 ASSERT3B(dmu_objset_is_snapshot(zilog->zl_os), ==, B_FALSE); 2659 2660 if (zilog->zl_sync == ZFS_SYNC_DISABLED) 2661 return; 2662 2663 if (!spa_writeable(zilog->zl_spa)) { 2664 /* 2665 * If the SPA is not writable, there should never be any 2666 * pending itxs waiting to be committed to disk. If that 2667 * weren't true, we'd skip writing those itxs out, and 2668 * would break the sematics of zil_commit(); thus, we're 2669 * verifying that truth before we return to the caller. 2670 */ 2671 ASSERT(list_is_empty(&zilog->zl_lwb_list)); 2672 ASSERT3P(zilog->zl_last_lwb_opened, ==, NULL); 2673 for (int i = 0; i < TXG_SIZE; i++) 2674 ASSERT3P(zilog->zl_itxg[i].itxg_itxs, ==, NULL); 2675 return; 2676 } 2677 2678 /* 2679 * If the ZIL is suspended, we don't want to dirty it by calling 2680 * zil_commit_itx_assign() below, nor can we write out 2681 * lwbs like would be done in zil_commit_write(). Thus, we 2682 * simply rely on txg_wait_synced() to maintain the necessary 2683 * semantics, and avoid calling those functions altogether. 2684 */ 2685 if (zilog->zl_suspend > 0) { 2686 txg_wait_synced(zilog->zl_dmu_pool, 0); 2687 return; 2688 } 2689 2690 zil_commit_impl(zilog, foid); 2691} 2692 2693void 2694zil_commit_impl(zilog_t *zilog, uint64_t foid) 2695{ 2696 /* 2697 * Move the "async" itxs for the specified foid to the "sync" 2698 * queues, such that they will be later committed (or skipped) 2699 * to an lwb when zil_process_commit_list() is called. 2700 * 2701 * Since these "async" itxs must be committed prior to this 2702 * call to zil_commit returning, we must perform this operation 2703 * before we call zil_commit_itx_assign(). 2704 */ 2705 zil_async_to_sync(zilog, foid); 2706 2707 /* 2708 * We allocate a new "waiter" structure which will initially be 2709 * linked to the commit itx using the itx's "itx_private" field. 2710 * Since the commit itx doesn't represent any on-disk state, 2711 * when it's committed to an lwb, rather than copying the its 2712 * lr_t into the lwb's buffer, the commit itx's "waiter" will be 2713 * added to the lwb's list of waiters. Then, when the lwb is 2714 * committed to stable storage, each waiter in the lwb's list of 2715 * waiters will be marked "done", and signalled. 2716 * 2717 * We must create the waiter and assign the commit itx prior to 2718 * calling zil_commit_writer(), or else our specific commit itx 2719 * is not guaranteed to be committed to an lwb prior to calling 2720 * zil_commit_waiter(). 2721 */ 2722 zil_commit_waiter_t *zcw = zil_alloc_commit_waiter(); 2723 zil_commit_itx_assign(zilog, zcw); 2724 2725 zil_commit_writer(zilog, zcw); 2726 zil_commit_waiter(zilog, zcw); 2727 2728 if (zcw->zcw_zio_error != 0) { 2729 /* 2730 * If there was an error writing out the ZIL blocks that 2731 * this thread is waiting on, then we fallback to 2732 * relying on spa_sync() to write out the data this 2733 * thread is waiting on. Obviously this has performance 2734 * implications, but the expectation is for this to be 2735 * an exceptional case, and shouldn't occur often. 2736 */ 2737 DTRACE_PROBE2(zil__commit__io__error, 2738 zilog_t *, zilog, zil_commit_waiter_t *, zcw); 2739 txg_wait_synced(zilog->zl_dmu_pool, 0); 2740 } 2741 2742 zil_free_commit_waiter(zcw); 2743} 2744 2745/* 2746 * Called in syncing context to free committed log blocks and update log header. 2747 */ 2748void 2749zil_sync(zilog_t *zilog, dmu_tx_t *tx) 2750{ 2751 zil_header_t *zh = zil_header_in_syncing_context(zilog); 2752 uint64_t txg = dmu_tx_get_txg(tx); 2753 spa_t *spa = zilog->zl_spa; 2754 uint64_t *replayed_seq = &zilog->zl_replayed_seq[txg & TXG_MASK]; 2755 lwb_t *lwb; 2756 2757 /* 2758 * We don't zero out zl_destroy_txg, so make sure we don't try 2759 * to destroy it twice. 2760 */ 2761 if (spa_sync_pass(spa) != 1) 2762 return; 2763 2764 mutex_enter(&zilog->zl_lock); 2765 2766 ASSERT(zilog->zl_stop_sync == 0); 2767 2768 if (*replayed_seq != 0) { 2769 ASSERT(zh->zh_replay_seq < *replayed_seq); 2770 zh->zh_replay_seq = *replayed_seq; 2771 *replayed_seq = 0; 2772 } 2773 2774 if (zilog->zl_destroy_txg == txg) { 2775 blkptr_t blk = zh->zh_log; 2776 2777 ASSERT(list_head(&zilog->zl_lwb_list) == NULL); 2778 2779 bzero(zh, sizeof (zil_header_t)); 2780 bzero(zilog->zl_replayed_seq, sizeof (zilog->zl_replayed_seq)); 2781 2782 if (zilog->zl_keep_first) { 2783 /* 2784 * If this block was part of log chain that couldn't 2785 * be claimed because a device was missing during 2786 * zil_claim(), but that device later returns, 2787 * then this block could erroneously appear valid. 2788 * To guard against this, assign a new GUID to the new 2789 * log chain so it doesn't matter what blk points to. 2790 */ 2791 zil_init_log_chain(zilog, &blk); 2792 zh->zh_log = blk; 2793 } 2794 } 2795 2796 while ((lwb = list_head(&zilog->zl_lwb_list)) != NULL) { 2797 zh->zh_log = lwb->lwb_blk; 2798 if (lwb->lwb_buf != NULL || lwb->lwb_max_txg > txg) 2799 break; 2800 list_remove(&zilog->zl_lwb_list, lwb); 2801 zio_free(spa, txg, &lwb->lwb_blk); 2802 zil_free_lwb(zilog, lwb); 2803 2804 /* 2805 * If we don't have anything left in the lwb list then 2806 * we've had an allocation failure and we need to zero 2807 * out the zil_header blkptr so that we don't end 2808 * up freeing the same block twice. 2809 */ 2810 if (list_head(&zilog->zl_lwb_list) == NULL) 2811 BP_ZERO(&zh->zh_log); 2812 } 2813 mutex_exit(&zilog->zl_lock); 2814} 2815 2816/* ARGSUSED */ 2817static int 2818zil_lwb_cons(void *vbuf, void *unused, int kmflag) 2819{ 2820 lwb_t *lwb = vbuf; 2821 list_create(&lwb->lwb_waiters, sizeof (zil_commit_waiter_t), 2822 offsetof(zil_commit_waiter_t, zcw_node)); 2823 avl_create(&lwb->lwb_vdev_tree, zil_lwb_vdev_compare, 2824 sizeof (zil_vdev_node_t), offsetof(zil_vdev_node_t, zv_node)); 2825 mutex_init(&lwb->lwb_vdev_lock, NULL, MUTEX_DEFAULT, NULL); 2826 return (0); 2827} 2828 2829/* ARGSUSED */ 2830static void 2831zil_lwb_dest(void *vbuf, void *unused) 2832{ 2833 lwb_t *lwb = vbuf; 2834 mutex_destroy(&lwb->lwb_vdev_lock); 2835 avl_destroy(&lwb->lwb_vdev_tree); 2836 list_destroy(&lwb->lwb_waiters); 2837} 2838 2839void 2840zil_init(void) 2841{ 2842 zil_lwb_cache = kmem_cache_create("zil_lwb_cache", 2843 sizeof (lwb_t), 0, zil_lwb_cons, zil_lwb_dest, NULL, NULL, NULL, 0); 2844 2845 zil_zcw_cache = kmem_cache_create("zil_zcw_cache", 2846 sizeof (zil_commit_waiter_t), 0, NULL, NULL, NULL, NULL, NULL, 0); 2847} 2848 2849void 2850zil_fini(void) 2851{ 2852 kmem_cache_destroy(zil_zcw_cache); 2853 kmem_cache_destroy(zil_lwb_cache); 2854} 2855 2856void 2857zil_set_sync(zilog_t *zilog, uint64_t sync) 2858{ 2859 zilog->zl_sync = sync; 2860} 2861 2862void 2863zil_set_logbias(zilog_t *zilog, uint64_t logbias) 2864{ 2865 zilog->zl_logbias = logbias; 2866} 2867 2868zilog_t * 2869zil_alloc(objset_t *os, zil_header_t *zh_phys) 2870{ 2871 zilog_t *zilog; 2872 2873 zilog = kmem_zalloc(sizeof (zilog_t), KM_SLEEP); 2874 2875 zilog->zl_header = zh_phys; 2876 zilog->zl_os = os; 2877 zilog->zl_spa = dmu_objset_spa(os); 2878 zilog->zl_dmu_pool = dmu_objset_pool(os); 2879 zilog->zl_destroy_txg = TXG_INITIAL - 1; 2880 zilog->zl_logbias = dmu_objset_logbias(os); 2881 zilog->zl_sync = dmu_objset_syncprop(os); 2882 zilog->zl_dirty_max_txg = 0; 2883 zilog->zl_last_lwb_opened = NULL; 2884 zilog->zl_last_lwb_latency = 0; 2885 2886 mutex_init(&zilog->zl_lock, NULL, MUTEX_DEFAULT, NULL); 2887 mutex_init(&zilog->zl_issuer_lock, NULL, MUTEX_DEFAULT, NULL); 2888 2889 for (int i = 0; i < TXG_SIZE; i++) { 2890 mutex_init(&zilog->zl_itxg[i].itxg_lock, NULL, 2891 MUTEX_DEFAULT, NULL); 2892 } 2893 2894 list_create(&zilog->zl_lwb_list, sizeof (lwb_t), 2895 offsetof(lwb_t, lwb_node)); 2896 2897 list_create(&zilog->zl_itx_commit_list, sizeof (itx_t), 2898 offsetof(itx_t, itx_node)); 2899 2900 cv_init(&zilog->zl_cv_suspend, NULL, CV_DEFAULT, NULL); 2901 2902 return (zilog); 2903} 2904 2905void 2906zil_free(zilog_t *zilog) 2907{ 2908 zilog->zl_stop_sync = 1; 2909 2910 ASSERT0(zilog->zl_suspend); 2911 ASSERT0(zilog->zl_suspending); 2912 2913 ASSERT(list_is_empty(&zilog->zl_lwb_list)); 2914 list_destroy(&zilog->zl_lwb_list); 2915 2916 ASSERT(list_is_empty(&zilog->zl_itx_commit_list)); 2917 list_destroy(&zilog->zl_itx_commit_list); 2918 2919 for (int i = 0; i < TXG_SIZE; i++) { 2920 /* 2921 * It's possible for an itx to be generated that doesn't dirty 2922 * a txg (e.g. ztest TX_TRUNCATE). So there's no zil_clean() 2923 * callback to remove the entry. We remove those here. 2924 * 2925 * Also free up the ziltest itxs. 2926 */ 2927 if (zilog->zl_itxg[i].itxg_itxs) 2928 zil_itxg_clean(zilog->zl_itxg[i].itxg_itxs); 2929 mutex_destroy(&zilog->zl_itxg[i].itxg_lock); 2930 } 2931 2932 mutex_destroy(&zilog->zl_issuer_lock); 2933 mutex_destroy(&zilog->zl_lock); 2934 2935 cv_destroy(&zilog->zl_cv_suspend); 2936 2937 kmem_free(zilog, sizeof (zilog_t)); 2938} 2939 2940/* 2941 * Open an intent log. 2942 */ 2943zilog_t * 2944zil_open(objset_t *os, zil_get_data_t *get_data) 2945{ 2946 zilog_t *zilog = dmu_objset_zil(os); 2947 2948 ASSERT3P(zilog->zl_get_data, ==, NULL); 2949 ASSERT3P(zilog->zl_last_lwb_opened, ==, NULL); 2950 ASSERT(list_is_empty(&zilog->zl_lwb_list)); 2951 2952 zilog->zl_get_data = get_data; 2953 2954 return (zilog); 2955} 2956 2957/* 2958 * Close an intent log. 2959 */ 2960void 2961zil_close(zilog_t *zilog) 2962{ 2963 lwb_t *lwb; 2964 uint64_t txg; 2965 2966 if (!dmu_objset_is_snapshot(zilog->zl_os)) { 2967 zil_commit(zilog, 0); 2968 } else { 2969 ASSERT3P(list_tail(&zilog->zl_lwb_list), ==, NULL); 2970 ASSERT0(zilog->zl_dirty_max_txg); 2971 ASSERT3B(zilog_is_dirty(zilog), ==, B_FALSE); 2972 } 2973 2974 mutex_enter(&zilog->zl_lock); 2975 lwb = list_tail(&zilog->zl_lwb_list); 2976 if (lwb == NULL) 2977 txg = zilog->zl_dirty_max_txg; 2978 else 2979 txg = MAX(zilog->zl_dirty_max_txg, lwb->lwb_max_txg); 2980 mutex_exit(&zilog->zl_lock); 2981 2982 /* 2983 * We need to use txg_wait_synced() to wait long enough for the 2984 * ZIL to be clean, and to wait for all pending lwbs to be 2985 * written out. 2986 */ 2987 if (txg != 0) 2988 txg_wait_synced(zilog->zl_dmu_pool, txg); 2989 2990 if (zilog_is_dirty(zilog)) 2991 zfs_dbgmsg("zil (%p) is dirty, txg %llu", zilog, txg); 2992 VERIFY(!zilog_is_dirty(zilog)); 2993 2994 zilog->zl_get_data = NULL; 2995 2996 /* 2997 * We should have only one lwb left on the list; remove it now. 2998 */ 2999 mutex_enter(&zilog->zl_lock); 3000 lwb = list_head(&zilog->zl_lwb_list); 3001 if (lwb != NULL) { 3002 ASSERT3P(lwb, ==, list_tail(&zilog->zl_lwb_list)); 3003 ASSERT3S(lwb->lwb_state, !=, LWB_STATE_ISSUED); 3004 list_remove(&zilog->zl_lwb_list, lwb); 3005 zio_buf_free(lwb->lwb_buf, lwb->lwb_sz); 3006 zil_free_lwb(zilog, lwb); 3007 } 3008 mutex_exit(&zilog->zl_lock); 3009} 3010 3011static char *suspend_tag = "zil suspending"; 3012 3013/* 3014 * Suspend an intent log. While in suspended mode, we still honor 3015 * synchronous semantics, but we rely on txg_wait_synced() to do it. 3016 * On old version pools, we suspend the log briefly when taking a 3017 * snapshot so that it will have an empty intent log. 3018 * 3019 * Long holds are not really intended to be used the way we do here -- 3020 * held for such a short time. A concurrent caller of dsl_dataset_long_held() 3021 * could fail. Therefore we take pains to only put a long hold if it is 3022 * actually necessary. Fortunately, it will only be necessary if the 3023 * objset is currently mounted (or the ZVOL equivalent). In that case it 3024 * will already have a long hold, so we are not really making things any worse. 3025 * 3026 * Ideally, we would locate the existing long-holder (i.e. the zfsvfs_t or 3027 * zvol_state_t), and use their mechanism to prevent their hold from being 3028 * dropped (e.g. VFS_HOLD()). However, that would be even more pain for 3029 * very little gain. 3030 * 3031 * if cookiep == NULL, this does both the suspend & resume. 3032 * Otherwise, it returns with the dataset "long held", and the cookie 3033 * should be passed into zil_resume(). 3034 */ 3035int 3036zil_suspend(const char *osname, void **cookiep) 3037{ 3038 objset_t *os; 3039 zilog_t *zilog; 3040 const zil_header_t *zh; 3041 int error; 3042 3043 error = dmu_objset_hold(osname, suspend_tag, &os); 3044 if (error != 0) 3045 return (error); 3046 zilog = dmu_objset_zil(os); 3047 3048 mutex_enter(&zilog->zl_lock); 3049 zh = zilog->zl_header; 3050 3051 if (zh->zh_flags & ZIL_REPLAY_NEEDED) { /* unplayed log */ 3052 mutex_exit(&zilog->zl_lock); 3053 dmu_objset_rele(os, suspend_tag); 3054 return (SET_ERROR(EBUSY)); 3055 } 3056 3057 /* 3058 * Don't put a long hold in the cases where we can avoid it. This 3059 * is when there is no cookie so we are doing a suspend & resume 3060 * (i.e. called from zil_vdev_offline()), and there's nothing to do 3061 * for the suspend because it's already suspended, or there's no ZIL. 3062 */ 3063 if (cookiep == NULL && !zilog->zl_suspending && 3064 (zilog->zl_suspend > 0 || BP_IS_HOLE(&zh->zh_log))) { 3065 mutex_exit(&zilog->zl_lock); 3066 dmu_objset_rele(os, suspend_tag); 3067 return (0); 3068 } 3069 3070 dsl_dataset_long_hold(dmu_objset_ds(os), suspend_tag); 3071 dsl_pool_rele(dmu_objset_pool(os), suspend_tag); 3072 3073 zilog->zl_suspend++; 3074 3075 if (zilog->zl_suspend > 1) { 3076 /* 3077 * Someone else is already suspending it. 3078 * Just wait for them to finish. 3079 */ 3080 3081 while (zilog->zl_suspending) 3082 cv_wait(&zilog->zl_cv_suspend, &zilog->zl_lock); 3083 mutex_exit(&zilog->zl_lock); 3084 3085 if (cookiep == NULL) 3086 zil_resume(os); 3087 else 3088 *cookiep = os; 3089 return (0); 3090 } 3091 3092 /* 3093 * If there is no pointer to an on-disk block, this ZIL must not 3094 * be active (e.g. filesystem not mounted), so there's nothing 3095 * to clean up. 3096 */ 3097 if (BP_IS_HOLE(&zh->zh_log)) { 3098 ASSERT(cookiep != NULL); /* fast path already handled */ 3099 3100 *cookiep = os; 3101 mutex_exit(&zilog->zl_lock); 3102 return (0); 3103 } 3104 3105 zilog->zl_suspending = B_TRUE; 3106 mutex_exit(&zilog->zl_lock); 3107 3108 /* 3109 * We need to use zil_commit_impl to ensure we wait for all 3110 * LWB_STATE_OPENED and LWB_STATE_ISSUED lwb's to be committed 3111 * to disk before proceeding. If we used zil_commit instead, it 3112 * would just call txg_wait_synced(), because zl_suspend is set. 3113 * txg_wait_synced() doesn't wait for these lwb's to be 3114 * LWB_STATE_DONE before returning. 3115 */ 3116 zil_commit_impl(zilog, 0); 3117 3118 /* 3119 * Now that we've ensured all lwb's are LWB_STATE_DONE, we use 3120 * txg_wait_synced() to ensure the data from the zilog has 3121 * migrated to the main pool before calling zil_destroy(). 3122 */ 3123 txg_wait_synced(zilog->zl_dmu_pool, 0); 3124 3125 zil_destroy(zilog, B_FALSE); 3126 3127 mutex_enter(&zilog->zl_lock); 3128 zilog->zl_suspending = B_FALSE; 3129 cv_broadcast(&zilog->zl_cv_suspend); 3130 mutex_exit(&zilog->zl_lock); 3131 3132 if (cookiep == NULL) 3133 zil_resume(os); 3134 else 3135 *cookiep = os; 3136 return (0); 3137} 3138 3139void 3140zil_resume(void *cookie) 3141{ 3142 objset_t *os = cookie; 3143 zilog_t *zilog = dmu_objset_zil(os); 3144 3145 mutex_enter(&zilog->zl_lock); 3146 ASSERT(zilog->zl_suspend != 0); 3147 zilog->zl_suspend--; 3148 mutex_exit(&zilog->zl_lock); 3149 dsl_dataset_long_rele(dmu_objset_ds(os), suspend_tag); 3150 dsl_dataset_rele(dmu_objset_ds(os), suspend_tag); 3151} 3152 3153typedef struct zil_replay_arg { 3154 zil_replay_func_t **zr_replay; 3155 void *zr_arg; 3156 boolean_t zr_byteswap; 3157 char *zr_lr; 3158} zil_replay_arg_t; 3159 3160static int 3161zil_replay_error(zilog_t *zilog, lr_t *lr, int error) 3162{ 3163 char name[ZFS_MAX_DATASET_NAME_LEN]; 3164 3165 zilog->zl_replaying_seq--; /* didn't actually replay this one */ 3166 3167 dmu_objset_name(zilog->zl_os, name); 3168 3169 cmn_err(CE_WARN, "ZFS replay transaction error %d, " 3170 "dataset %s, seq 0x%llx, txtype %llu %s\n", error, name, 3171 (u_longlong_t)lr->lrc_seq, 3172 (u_longlong_t)(lr->lrc_txtype & ~TX_CI), 3173 (lr->lrc_txtype & TX_CI) ? "CI" : ""); 3174 3175 return (error); 3176} 3177 3178static int 3179zil_replay_log_record(zilog_t *zilog, lr_t *lr, void *zra, uint64_t claim_txg) 3180{ 3181 zil_replay_arg_t *zr = zra; 3182 const zil_header_t *zh = zilog->zl_header; 3183 uint64_t reclen = lr->lrc_reclen; 3184 uint64_t txtype = lr->lrc_txtype; 3185 int error = 0; 3186 3187 zilog->zl_replaying_seq = lr->lrc_seq; 3188 3189 if (lr->lrc_seq <= zh->zh_replay_seq) /* already replayed */ 3190 return (0); 3191 3192 if (lr->lrc_txg < claim_txg) /* already committed */ 3193 return (0); 3194 3195 /* Strip case-insensitive bit, still present in log record */ 3196 txtype &= ~TX_CI; 3197 3198 if (txtype == 0 || txtype >= TX_MAX_TYPE) 3199 return (zil_replay_error(zilog, lr, EINVAL)); 3200 3201 /* 3202 * If this record type can be logged out of order, the object 3203 * (lr_foid) may no longer exist. That's legitimate, not an error. 3204 */ 3205 if (TX_OOO(txtype)) { 3206 error = dmu_object_info(zilog->zl_os, 3207 ((lr_ooo_t *)lr)->lr_foid, NULL); 3208 if (error == ENOENT || error == EEXIST) 3209 return (0); 3210 } 3211 3212 /* 3213 * Make a copy of the data so we can revise and extend it. 3214 */ 3215 bcopy(lr, zr->zr_lr, reclen); 3216 3217 /* 3218 * If this is a TX_WRITE with a blkptr, suck in the data. 3219 */ 3220 if (txtype == TX_WRITE && reclen == sizeof (lr_write_t)) { 3221 error = zil_read_log_data(zilog, (lr_write_t *)lr, 3222 zr->zr_lr + reclen); 3223 if (error != 0) 3224 return (zil_replay_error(zilog, lr, error)); 3225 } 3226 3227 /* 3228 * The log block containing this lr may have been byteswapped 3229 * so that we can easily examine common fields like lrc_txtype. 3230 * However, the log is a mix of different record types, and only the 3231 * replay vectors know how to byteswap their records. Therefore, if 3232 * the lr was byteswapped, undo it before invoking the replay vector. 3233 */ 3234 if (zr->zr_byteswap) 3235 byteswap_uint64_array(zr->zr_lr, reclen); 3236 3237 /* 3238 * We must now do two things atomically: replay this log record, 3239 * and update the log header sequence number to reflect the fact that 3240 * we did so. At the end of each replay function the sequence number 3241 * is updated if we are in replay mode. 3242 */ 3243 error = zr->zr_replay[txtype](zr->zr_arg, zr->zr_lr, zr->zr_byteswap); 3244 if (error != 0) { 3245 /* 3246 * The DMU's dnode layer doesn't see removes until the txg 3247 * commits, so a subsequent claim can spuriously fail with 3248 * EEXIST. So if we receive any error we try syncing out 3249 * any removes then retry the transaction. Note that we 3250 * specify B_FALSE for byteswap now, so we don't do it twice. 3251 */ 3252 txg_wait_synced(spa_get_dsl(zilog->zl_spa), 0); 3253 error = zr->zr_replay[txtype](zr->zr_arg, zr->zr_lr, B_FALSE); 3254 if (error != 0) 3255 return (zil_replay_error(zilog, lr, error)); 3256 } 3257 return (0); 3258} 3259 3260/* ARGSUSED */ 3261static int 3262zil_incr_blks(zilog_t *zilog, blkptr_t *bp, void *arg, uint64_t claim_txg) 3263{ 3264 zilog->zl_replay_blks++; 3265 3266 return (0); 3267} 3268 3269/* 3270 * If this dataset has a non-empty intent log, replay it and destroy it. 3271 */ 3272void 3273zil_replay(objset_t *os, void *arg, zil_replay_func_t *replay_func[TX_MAX_TYPE]) 3274{ 3275 zilog_t *zilog = dmu_objset_zil(os); 3276 const zil_header_t *zh = zilog->zl_header; 3277 zil_replay_arg_t zr; 3278 3279 if ((zh->zh_flags & ZIL_REPLAY_NEEDED) == 0) { 3280 zil_destroy(zilog, B_TRUE); 3281 return; 3282 } 3283 3284 zr.zr_replay = replay_func; 3285 zr.zr_arg = arg; 3286 zr.zr_byteswap = BP_SHOULD_BYTESWAP(&zh->zh_log); 3287 zr.zr_lr = kmem_alloc(2 * SPA_MAXBLOCKSIZE, KM_SLEEP); 3288 3289 /* 3290 * Wait for in-progress removes to sync before starting replay. 3291 */ 3292 txg_wait_synced(zilog->zl_dmu_pool, 0); 3293 3294 zilog->zl_replay = B_TRUE; 3295 zilog->zl_replay_time = ddi_get_lbolt(); 3296 ASSERT(zilog->zl_replay_blks == 0); 3297 (void) zil_parse(zilog, zil_incr_blks, zil_replay_log_record, &zr, 3298 zh->zh_claim_txg); 3299 kmem_free(zr.zr_lr, 2 * SPA_MAXBLOCKSIZE); 3300 3301 zil_destroy(zilog, B_FALSE); 3302 txg_wait_synced(zilog->zl_dmu_pool, zilog->zl_destroy_txg); 3303 zilog->zl_replay = B_FALSE; 3304} 3305 3306boolean_t 3307zil_replaying(zilog_t *zilog, dmu_tx_t *tx) 3308{ 3309 if (zilog->zl_sync == ZFS_SYNC_DISABLED) 3310 return (B_TRUE); 3311 3312 if (zilog->zl_replay) { 3313 dsl_dataset_dirty(dmu_objset_ds(zilog->zl_os), tx); 3314 zilog->zl_replayed_seq[dmu_tx_get_txg(tx) & TXG_MASK] = 3315 zilog->zl_replaying_seq; 3316 return (B_TRUE); 3317 } 3318 3319 return (B_FALSE); 3320} 3321 3322/* ARGSUSED */ 3323int 3324zil_reset(const char *osname, void *arg) 3325{ 3326 int error; 3327 3328 error = zil_suspend(osname, NULL); 3329 if (error != 0) 3330 return (SET_ERROR(EEXIST)); 3331 return (0); 3332} 3333