1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21 /* 22 * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved. 23 * Copyright (c) 2013 by Delphix. All rights reserved. 24 * Copyright (c) 2011 Nexenta Systems, Inc. All rights reserved. 25 */ 26 27 #include <sys/zfs_context.h> 28 #include <sys/fm/fs/zfs.h> 29 #include <sys/spa.h> 30 #include <sys/txg.h> 31 #include <sys/spa_impl.h> 32 #include <sys/vdev_impl.h> 33 #include <sys/zio_impl.h> 34 #include <sys/zio_compress.h> 35 #include <sys/zio_checksum.h> 36 #include <sys/dmu_objset.h> 37 #include <sys/arc.h> 38 #include <sys/ddt.h> 39 40 /* 41 * ========================================================================== 42 * I/O type descriptions 43 * ========================================================================== 44 */ 45 const char *zio_type_name[ZIO_TYPES] = { 46 "zio_null", "zio_read", "zio_write", "zio_free", "zio_claim", 47 "zio_ioctl" 48 }; 49 50 /* 51 * ========================================================================== 52 * I/O kmem caches 53 * ========================================================================== 54 */ 55 kmem_cache_t *zio_cache; 56 kmem_cache_t *zio_link_cache; 57 kmem_cache_t *zio_buf_cache[SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT]; 58 kmem_cache_t *zio_data_buf_cache[SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT]; 59 60 #ifdef _KERNEL 61 extern vmem_t *zio_alloc_arena; 62 #endif 63 extern int zfs_mg_alloc_failures; 64 65 /* 66 * The following actions directly effect the spa's sync-to-convergence logic. 67 * The values below define the sync pass when we start performing the action. 68 * Care should be taken when changing these values as they directly impact 69 * spa_sync() performance. Tuning these values may introduce subtle performance 70 * pathologies and should only be done in the context of performance analysis. 71 * These tunables will eventually be removed and replaced with #defines once 72 * enough analysis has been done to determine optimal values. 73 * 74 * The 'zfs_sync_pass_deferred_free' pass must be greater than 1 to ensure that 75 * regular blocks are not deferred. 76 */ 77 int zfs_sync_pass_deferred_free = 2; /* defer frees starting in this pass */ 78 int zfs_sync_pass_dont_compress = 5; /* don't compress starting in this pass */ 79 int zfs_sync_pass_rewrite = 2; /* rewrite new bps starting in this pass */ 80 81 /* 82 * An allocating zio is one that either currently has the DVA allocate 83 * stage set or will have it later in its lifetime. 84 */ 85 #define IO_IS_ALLOCATING(zio) ((zio)->io_orig_pipeline & ZIO_STAGE_DVA_ALLOCATE) 86 87 boolean_t zio_requeue_io_start_cut_in_line = B_TRUE; 88 89 #ifdef ZFS_DEBUG 90 int zio_buf_debug_limit = 16384; 91 #else 92 int zio_buf_debug_limit = 0; 93 #endif 94 95 void 96 zio_init(void) 97 { 98 size_t c; 99 vmem_t *data_alloc_arena = NULL; 100 101 #ifdef _KERNEL 102 data_alloc_arena = zio_alloc_arena; 103 #endif 104 zio_cache = kmem_cache_create("zio_cache", 105 sizeof (zio_t), 0, NULL, NULL, NULL, NULL, NULL, 0); 106 zio_link_cache = kmem_cache_create("zio_link_cache", 107 sizeof (zio_link_t), 0, NULL, NULL, NULL, NULL, NULL, 0); 108 109 /* 110 * For small buffers, we want a cache for each multiple of 111 * SPA_MINBLOCKSIZE. For medium-size buffers, we want a cache 112 * for each quarter-power of 2. For large buffers, we want 113 * a cache for each multiple of PAGESIZE. 114 */ 115 for (c = 0; c < SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT; c++) { 116 size_t size = (c + 1) << SPA_MINBLOCKSHIFT; 117 size_t p2 = size; 118 size_t align = 0; 119 size_t cflags = (size > zio_buf_debug_limit) ? KMC_NODEBUG : 0; 120 121 while (p2 & (p2 - 1)) 122 p2 &= p2 - 1; 123 124 #ifndef _KERNEL 125 /* 126 * If we are using watchpoints, put each buffer on its own page, 127 * to eliminate the performance overhead of trapping to the 128 * kernel when modifying a non-watched buffer that shares the 129 * page with a watched buffer. 130 */ 131 if (arc_watch && !IS_P2ALIGNED(size, PAGESIZE)) 132 continue; 133 #endif 134 if (size <= 4 * SPA_MINBLOCKSIZE) { 135 align = SPA_MINBLOCKSIZE; 136 } else if (IS_P2ALIGNED(size, PAGESIZE)) { 137 align = PAGESIZE; 138 } else if (IS_P2ALIGNED(size, p2 >> 2)) { 139 align = p2 >> 2; 140 } 141 142 if (align != 0) { 143 char name[36]; 144 (void) sprintf(name, "zio_buf_%lu", (ulong_t)size); 145 zio_buf_cache[c] = kmem_cache_create(name, size, 146 align, NULL, NULL, NULL, NULL, NULL, cflags); 147 148 /* 149 * Since zio_data bufs do not appear in crash dumps, we 150 * pass KMC_NOTOUCH so that no allocator metadata is 151 * stored with the buffers. 152 */ 153 (void) sprintf(name, "zio_data_buf_%lu", (ulong_t)size); 154 zio_data_buf_cache[c] = kmem_cache_create(name, size, 155 align, NULL, NULL, NULL, NULL, data_alloc_arena, 156 cflags | KMC_NOTOUCH); 157 } 158 } 159 160 while (--c != 0) { 161 ASSERT(zio_buf_cache[c] != NULL); 162 if (zio_buf_cache[c - 1] == NULL) 163 zio_buf_cache[c - 1] = zio_buf_cache[c]; 164 165 ASSERT(zio_data_buf_cache[c] != NULL); 166 if (zio_data_buf_cache[c - 1] == NULL) 167 zio_data_buf_cache[c - 1] = zio_data_buf_cache[c]; 168 } 169 170 /* 171 * The zio write taskqs have 1 thread per cpu, allow 1/2 of the taskqs 172 * to fail 3 times per txg or 8 failures, whichever is greater. 173 */ 174 if (zfs_mg_alloc_failures == 0) 175 zfs_mg_alloc_failures = MAX((3 * max_ncpus / 2), 8); 176 177 zio_inject_init(); 178 } 179 180 void 181 zio_fini(void) 182 { 183 size_t c; 184 kmem_cache_t *last_cache = NULL; 185 kmem_cache_t *last_data_cache = NULL; 186 187 for (c = 0; c < SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT; c++) { 188 if (zio_buf_cache[c] != last_cache) { 189 last_cache = zio_buf_cache[c]; 190 kmem_cache_destroy(zio_buf_cache[c]); 191 } 192 zio_buf_cache[c] = NULL; 193 194 if (zio_data_buf_cache[c] != last_data_cache) { 195 last_data_cache = zio_data_buf_cache[c]; 196 kmem_cache_destroy(zio_data_buf_cache[c]); 197 } 198 zio_data_buf_cache[c] = NULL; 199 } 200 201 kmem_cache_destroy(zio_link_cache); 202 kmem_cache_destroy(zio_cache); 203 204 zio_inject_fini(); 205 } 206 207 /* 208 * ========================================================================== 209 * Allocate and free I/O buffers 210 * ========================================================================== 211 */ 212 213 /* 214 * Use zio_buf_alloc to allocate ZFS metadata. This data will appear in a 215 * crashdump if the kernel panics, so use it judiciously. Obviously, it's 216 * useful to inspect ZFS metadata, but if possible, we should avoid keeping 217 * excess / transient data in-core during a crashdump. 218 */ 219 void * 220 zio_buf_alloc(size_t size) 221 { 222 size_t c = (size - 1) >> SPA_MINBLOCKSHIFT; 223 224 ASSERT(c < SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT); 225 226 return (kmem_cache_alloc(zio_buf_cache[c], KM_PUSHPAGE)); 227 } 228 229 /* 230 * Use zio_data_buf_alloc to allocate data. The data will not appear in a 231 * crashdump if the kernel panics. This exists so that we will limit the amount 232 * of ZFS data that shows up in a kernel crashdump. (Thus reducing the amount 233 * of kernel heap dumped to disk when the kernel panics) 234 */ 235 void * 236 zio_data_buf_alloc(size_t size) 237 { 238 size_t c = (size - 1) >> SPA_MINBLOCKSHIFT; 239 240 ASSERT(c < SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT); 241 242 return (kmem_cache_alloc(zio_data_buf_cache[c], KM_PUSHPAGE)); 243 } 244 245 void 246 zio_buf_free(void *buf, size_t size) 247 { 248 size_t c = (size - 1) >> SPA_MINBLOCKSHIFT; 249 250 ASSERT(c < SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT); 251 252 kmem_cache_free(zio_buf_cache[c], buf); 253 } 254 255 void 256 zio_data_buf_free(void *buf, size_t size) 257 { 258 size_t c = (size - 1) >> SPA_MINBLOCKSHIFT; 259 260 ASSERT(c < SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT); 261 262 kmem_cache_free(zio_data_buf_cache[c], buf); 263 } 264 265 /* 266 * ========================================================================== 267 * Push and pop I/O transform buffers 268 * ========================================================================== 269 */ 270 static void 271 zio_push_transform(zio_t *zio, void *data, uint64_t size, uint64_t bufsize, 272 zio_transform_func_t *transform) 273 { 274 zio_transform_t *zt = kmem_alloc(sizeof (zio_transform_t), KM_SLEEP); 275 276 zt->zt_orig_data = zio->io_data; 277 zt->zt_orig_size = zio->io_size; 278 zt->zt_bufsize = bufsize; 279 zt->zt_transform = transform; 280 281 zt->zt_next = zio->io_transform_stack; 282 zio->io_transform_stack = zt; 283 284 zio->io_data = data; 285 zio->io_size = size; 286 } 287 288 static void 289 zio_pop_transforms(zio_t *zio) 290 { 291 zio_transform_t *zt; 292 293 while ((zt = zio->io_transform_stack) != NULL) { 294 if (zt->zt_transform != NULL) 295 zt->zt_transform(zio, 296 zt->zt_orig_data, zt->zt_orig_size); 297 298 if (zt->zt_bufsize != 0) 299 zio_buf_free(zio->io_data, zt->zt_bufsize); 300 301 zio->io_data = zt->zt_orig_data; 302 zio->io_size = zt->zt_orig_size; 303 zio->io_transform_stack = zt->zt_next; 304 305 kmem_free(zt, sizeof (zio_transform_t)); 306 } 307 } 308 309 /* 310 * ========================================================================== 311 * I/O transform callbacks for subblocks and decompression 312 * ========================================================================== 313 */ 314 static void 315 zio_subblock(zio_t *zio, void *data, uint64_t size) 316 { 317 ASSERT(zio->io_size > size); 318 319 if (zio->io_type == ZIO_TYPE_READ) 320 bcopy(zio->io_data, data, size); 321 } 322 323 static void 324 zio_decompress(zio_t *zio, void *data, uint64_t size) 325 { 326 if (zio->io_error == 0 && 327 zio_decompress_data(BP_GET_COMPRESS(zio->io_bp), 328 zio->io_data, data, zio->io_size, size) != 0) 329 zio->io_error = SET_ERROR(EIO); 330 } 331 332 /* 333 * ========================================================================== 334 * I/O parent/child relationships and pipeline interlocks 335 * ========================================================================== 336 */ 337 /* 338 * NOTE - Callers to zio_walk_parents() and zio_walk_children must 339 * continue calling these functions until they return NULL. 340 * Otherwise, the next caller will pick up the list walk in 341 * some indeterminate state. (Otherwise every caller would 342 * have to pass in a cookie to keep the state represented by 343 * io_walk_link, which gets annoying.) 344 */ 345 zio_t * 346 zio_walk_parents(zio_t *cio) 347 { 348 zio_link_t *zl = cio->io_walk_link; 349 list_t *pl = &cio->io_parent_list; 350 351 zl = (zl == NULL) ? list_head(pl) : list_next(pl, zl); 352 cio->io_walk_link = zl; 353 354 if (zl == NULL) 355 return (NULL); 356 357 ASSERT(zl->zl_child == cio); 358 return (zl->zl_parent); 359 } 360 361 zio_t * 362 zio_walk_children(zio_t *pio) 363 { 364 zio_link_t *zl = pio->io_walk_link; 365 list_t *cl = &pio->io_child_list; 366 367 zl = (zl == NULL) ? list_head(cl) : list_next(cl, zl); 368 pio->io_walk_link = zl; 369 370 if (zl == NULL) 371 return (NULL); 372 373 ASSERT(zl->zl_parent == pio); 374 return (zl->zl_child); 375 } 376 377 zio_t * 378 zio_unique_parent(zio_t *cio) 379 { 380 zio_t *pio = zio_walk_parents(cio); 381 382 VERIFY(zio_walk_parents(cio) == NULL); 383 return (pio); 384 } 385 386 void 387 zio_add_child(zio_t *pio, zio_t *cio) 388 { 389 zio_link_t *zl = kmem_cache_alloc(zio_link_cache, KM_SLEEP); 390 391 /* 392 * Logical I/Os can have logical, gang, or vdev children. 393 * Gang I/Os can have gang or vdev children. 394 * Vdev I/Os can only have vdev children. 395 * The following ASSERT captures all of these constraints. 396 */ 397 ASSERT(cio->io_child_type <= pio->io_child_type); 398 399 zl->zl_parent = pio; 400 zl->zl_child = cio; 401 402 mutex_enter(&cio->io_lock); 403 mutex_enter(&pio->io_lock); 404 405 ASSERT(pio->io_state[ZIO_WAIT_DONE] == 0); 406 407 for (int w = 0; w < ZIO_WAIT_TYPES; w++) 408 pio->io_children[cio->io_child_type][w] += !cio->io_state[w]; 409 410 list_insert_head(&pio->io_child_list, zl); 411 list_insert_head(&cio->io_parent_list, zl); 412 413 pio->io_child_count++; 414 cio->io_parent_count++; 415 416 mutex_exit(&pio->io_lock); 417 mutex_exit(&cio->io_lock); 418 } 419 420 static void 421 zio_remove_child(zio_t *pio, zio_t *cio, zio_link_t *zl) 422 { 423 ASSERT(zl->zl_parent == pio); 424 ASSERT(zl->zl_child == cio); 425 426 mutex_enter(&cio->io_lock); 427 mutex_enter(&pio->io_lock); 428 429 list_remove(&pio->io_child_list, zl); 430 list_remove(&cio->io_parent_list, zl); 431 432 pio->io_child_count--; 433 cio->io_parent_count--; 434 435 mutex_exit(&pio->io_lock); 436 mutex_exit(&cio->io_lock); 437 438 kmem_cache_free(zio_link_cache, zl); 439 } 440 441 static boolean_t 442 zio_wait_for_children(zio_t *zio, enum zio_child child, enum zio_wait_type wait) 443 { 444 uint64_t *countp = &zio->io_children[child][wait]; 445 boolean_t waiting = B_FALSE; 446 447 mutex_enter(&zio->io_lock); 448 ASSERT(zio->io_stall == NULL); 449 if (*countp != 0) { 450 zio->io_stage >>= 1; 451 zio->io_stall = countp; 452 waiting = B_TRUE; 453 } 454 mutex_exit(&zio->io_lock); 455 456 return (waiting); 457 } 458 459 static void 460 zio_notify_parent(zio_t *pio, zio_t *zio, enum zio_wait_type wait) 461 { 462 uint64_t *countp = &pio->io_children[zio->io_child_type][wait]; 463 int *errorp = &pio->io_child_error[zio->io_child_type]; 464 465 mutex_enter(&pio->io_lock); 466 if (zio->io_error && !(zio->io_flags & ZIO_FLAG_DONT_PROPAGATE)) 467 *errorp = zio_worst_error(*errorp, zio->io_error); 468 pio->io_reexecute |= zio->io_reexecute; 469 ASSERT3U(*countp, >, 0); 470 471 (*countp)--; 472 473 if (*countp == 0 && pio->io_stall == countp) { 474 pio->io_stall = NULL; 475 mutex_exit(&pio->io_lock); 476 zio_execute(pio); 477 } else { 478 mutex_exit(&pio->io_lock); 479 } 480 } 481 482 static void 483 zio_inherit_child_errors(zio_t *zio, enum zio_child c) 484 { 485 if (zio->io_child_error[c] != 0 && zio->io_error == 0) 486 zio->io_error = zio->io_child_error[c]; 487 } 488 489 /* 490 * ========================================================================== 491 * Create the various types of I/O (read, write, free, etc) 492 * ========================================================================== 493 */ 494 static zio_t * 495 zio_create(zio_t *pio, spa_t *spa, uint64_t txg, const blkptr_t *bp, 496 void *data, uint64_t size, zio_done_func_t *done, void *private, 497 zio_type_t type, zio_priority_t priority, enum zio_flag flags, 498 vdev_t *vd, uint64_t offset, const zbookmark_t *zb, 499 enum zio_stage stage, enum zio_stage pipeline) 500 { 501 zio_t *zio; 502 503 ASSERT3U(size, <=, SPA_MAXBLOCKSIZE); 504 ASSERT(P2PHASE(size, SPA_MINBLOCKSIZE) == 0); 505 ASSERT(P2PHASE(offset, SPA_MINBLOCKSIZE) == 0); 506 507 ASSERT(!vd || spa_config_held(spa, SCL_STATE_ALL, RW_READER)); 508 ASSERT(!bp || !(flags & ZIO_FLAG_CONFIG_WRITER)); 509 ASSERT(vd || stage == ZIO_STAGE_OPEN); 510 511 zio = kmem_cache_alloc(zio_cache, KM_SLEEP); 512 bzero(zio, sizeof (zio_t)); 513 514 mutex_init(&zio->io_lock, NULL, MUTEX_DEFAULT, NULL); 515 cv_init(&zio->io_cv, NULL, CV_DEFAULT, NULL); 516 517 list_create(&zio->io_parent_list, sizeof (zio_link_t), 518 offsetof(zio_link_t, zl_parent_node)); 519 list_create(&zio->io_child_list, sizeof (zio_link_t), 520 offsetof(zio_link_t, zl_child_node)); 521 522 if (vd != NULL) 523 zio->io_child_type = ZIO_CHILD_VDEV; 524 else if (flags & ZIO_FLAG_GANG_CHILD) 525 zio->io_child_type = ZIO_CHILD_GANG; 526 else if (flags & ZIO_FLAG_DDT_CHILD) 527 zio->io_child_type = ZIO_CHILD_DDT; 528 else 529 zio->io_child_type = ZIO_CHILD_LOGICAL; 530 531 if (bp != NULL) { 532 zio->io_bp = (blkptr_t *)bp; 533 zio->io_bp_copy = *bp; 534 zio->io_bp_orig = *bp; 535 if (type != ZIO_TYPE_WRITE || 536 zio->io_child_type == ZIO_CHILD_DDT) 537 zio->io_bp = &zio->io_bp_copy; /* so caller can free */ 538 if (zio->io_child_type == ZIO_CHILD_LOGICAL) 539 zio->io_logical = zio; 540 if (zio->io_child_type > ZIO_CHILD_GANG && BP_IS_GANG(bp)) 541 pipeline |= ZIO_GANG_STAGES; 542 } 543 544 zio->io_spa = spa; 545 zio->io_txg = txg; 546 zio->io_done = done; 547 zio->io_private = private; 548 zio->io_type = type; 549 zio->io_priority = priority; 550 zio->io_vd = vd; 551 zio->io_offset = offset; 552 zio->io_orig_data = zio->io_data = data; 553 zio->io_orig_size = zio->io_size = size; 554 zio->io_orig_flags = zio->io_flags = flags; 555 zio->io_orig_stage = zio->io_stage = stage; 556 zio->io_orig_pipeline = zio->io_pipeline = pipeline; 557 558 zio->io_state[ZIO_WAIT_READY] = (stage >= ZIO_STAGE_READY); 559 zio->io_state[ZIO_WAIT_DONE] = (stage >= ZIO_STAGE_DONE); 560 561 if (zb != NULL) 562 zio->io_bookmark = *zb; 563 564 if (pio != NULL) { 565 if (zio->io_logical == NULL) 566 zio->io_logical = pio->io_logical; 567 if (zio->io_child_type == ZIO_CHILD_GANG) 568 zio->io_gang_leader = pio->io_gang_leader; 569 zio_add_child(pio, zio); 570 } 571 572 return (zio); 573 } 574 575 static void 576 zio_destroy(zio_t *zio) 577 { 578 list_destroy(&zio->io_parent_list); 579 list_destroy(&zio->io_child_list); 580 mutex_destroy(&zio->io_lock); 581 cv_destroy(&zio->io_cv); 582 kmem_cache_free(zio_cache, zio); 583 } 584 585 zio_t * 586 zio_null(zio_t *pio, spa_t *spa, vdev_t *vd, zio_done_func_t *done, 587 void *private, enum zio_flag flags) 588 { 589 zio_t *zio; 590 591 zio = zio_create(pio, spa, 0, NULL, NULL, 0, done, private, 592 ZIO_TYPE_NULL, ZIO_PRIORITY_NOW, flags, vd, 0, NULL, 593 ZIO_STAGE_OPEN, ZIO_INTERLOCK_PIPELINE); 594 595 return (zio); 596 } 597 598 zio_t * 599 zio_root(spa_t *spa, zio_done_func_t *done, void *private, enum zio_flag flags) 600 { 601 return (zio_null(NULL, spa, NULL, done, private, flags)); 602 } 603 604 zio_t * 605 zio_read(zio_t *pio, spa_t *spa, const blkptr_t *bp, 606 void *data, uint64_t size, zio_done_func_t *done, void *private, 607 zio_priority_t priority, enum zio_flag flags, const zbookmark_t *zb) 608 { 609 zio_t *zio; 610 611 zio = zio_create(pio, spa, BP_PHYSICAL_BIRTH(bp), bp, 612 data, size, done, private, 613 ZIO_TYPE_READ, priority, flags, NULL, 0, zb, 614 ZIO_STAGE_OPEN, (flags & ZIO_FLAG_DDT_CHILD) ? 615 ZIO_DDT_CHILD_READ_PIPELINE : ZIO_READ_PIPELINE); 616 617 return (zio); 618 } 619 620 zio_t * 621 zio_write(zio_t *pio, spa_t *spa, uint64_t txg, blkptr_t *bp, 622 void *data, uint64_t size, const zio_prop_t *zp, 623 zio_done_func_t *ready, zio_done_func_t *physdone, zio_done_func_t *done, 624 void *private, 625 zio_priority_t priority, enum zio_flag flags, const zbookmark_t *zb) 626 { 627 zio_t *zio; 628 629 ASSERT(zp->zp_checksum >= ZIO_CHECKSUM_OFF && 630 zp->zp_checksum < ZIO_CHECKSUM_FUNCTIONS && 631 zp->zp_compress >= ZIO_COMPRESS_OFF && 632 zp->zp_compress < ZIO_COMPRESS_FUNCTIONS && 633 DMU_OT_IS_VALID(zp->zp_type) && 634 zp->zp_level < 32 && 635 zp->zp_copies > 0 && 636 zp->zp_copies <= spa_max_replication(spa)); 637 638 zio = zio_create(pio, spa, txg, bp, data, size, done, private, 639 ZIO_TYPE_WRITE, priority, flags, NULL, 0, zb, 640 ZIO_STAGE_OPEN, (flags & ZIO_FLAG_DDT_CHILD) ? 641 ZIO_DDT_CHILD_WRITE_PIPELINE : ZIO_WRITE_PIPELINE); 642 643 zio->io_ready = ready; 644 zio->io_physdone = physdone; 645 zio->io_prop = *zp; 646 647 return (zio); 648 } 649 650 zio_t * 651 zio_rewrite(zio_t *pio, spa_t *spa, uint64_t txg, blkptr_t *bp, void *data, 652 uint64_t size, zio_done_func_t *done, void *private, 653 zio_priority_t priority, enum zio_flag flags, zbookmark_t *zb) 654 { 655 zio_t *zio; 656 657 zio = zio_create(pio, spa, txg, bp, data, size, done, private, 658 ZIO_TYPE_WRITE, priority, flags, NULL, 0, zb, 659 ZIO_STAGE_OPEN, ZIO_REWRITE_PIPELINE); 660 661 return (zio); 662 } 663 664 void 665 zio_write_override(zio_t *zio, blkptr_t *bp, int copies, boolean_t nopwrite) 666 { 667 ASSERT(zio->io_type == ZIO_TYPE_WRITE); 668 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL); 669 ASSERT(zio->io_stage == ZIO_STAGE_OPEN); 670 ASSERT(zio->io_txg == spa_syncing_txg(zio->io_spa)); 671 672 /* 673 * We must reset the io_prop to match the values that existed 674 * when the bp was first written by dmu_sync() keeping in mind 675 * that nopwrite and dedup are mutually exclusive. 676 */ 677 zio->io_prop.zp_dedup = nopwrite ? B_FALSE : zio->io_prop.zp_dedup; 678 zio->io_prop.zp_nopwrite = nopwrite; 679 zio->io_prop.zp_copies = copies; 680 zio->io_bp_override = bp; 681 } 682 683 void 684 zio_free(spa_t *spa, uint64_t txg, const blkptr_t *bp) 685 { 686 metaslab_check_free(spa, bp); 687 688 /* 689 * Frees that are for the currently-syncing txg, are not going to be 690 * deferred, and which will not need to do a read (i.e. not GANG or 691 * DEDUP), can be processed immediately. Otherwise, put them on the 692 * in-memory list for later processing. 693 */ 694 if (BP_IS_GANG(bp) || BP_GET_DEDUP(bp) || 695 txg != spa->spa_syncing_txg || 696 spa_sync_pass(spa) >= zfs_sync_pass_deferred_free) { 697 bplist_append(&spa->spa_free_bplist[txg & TXG_MASK], bp); 698 } else { 699 VERIFY0(zio_wait(zio_free_sync(NULL, spa, txg, bp, 0))); 700 } 701 } 702 703 zio_t * 704 zio_free_sync(zio_t *pio, spa_t *spa, uint64_t txg, const blkptr_t *bp, 705 enum zio_flag flags) 706 { 707 zio_t *zio; 708 enum zio_stage stage = ZIO_FREE_PIPELINE; 709 710 dprintf_bp(bp, "freeing in txg %llu, pass %u", 711 (longlong_t)txg, spa->spa_sync_pass); 712 713 ASSERT(!BP_IS_HOLE(bp)); 714 ASSERT(spa_syncing_txg(spa) == txg); 715 ASSERT(spa_sync_pass(spa) < zfs_sync_pass_deferred_free); 716 717 metaslab_check_free(spa, bp); 718 arc_freed(spa, bp); 719 720 /* 721 * GANG and DEDUP blocks can induce a read (for the gang block header, 722 * or the DDT), so issue them asynchronously so that this thread is 723 * not tied up. 724 */ 725 if (BP_IS_GANG(bp) || BP_GET_DEDUP(bp)) 726 stage |= ZIO_STAGE_ISSUE_ASYNC; 727 728 zio = zio_create(pio, spa, txg, bp, NULL, BP_GET_PSIZE(bp), 729 NULL, NULL, ZIO_TYPE_FREE, ZIO_PRIORITY_NOW, flags, 730 NULL, 0, NULL, ZIO_STAGE_OPEN, stage); 731 732 733 return (zio); 734 } 735 736 zio_t * 737 zio_claim(zio_t *pio, spa_t *spa, uint64_t txg, const blkptr_t *bp, 738 zio_done_func_t *done, void *private, enum zio_flag flags) 739 { 740 zio_t *zio; 741 742 /* 743 * A claim is an allocation of a specific block. Claims are needed 744 * to support immediate writes in the intent log. The issue is that 745 * immediate writes contain committed data, but in a txg that was 746 * *not* committed. Upon opening the pool after an unclean shutdown, 747 * the intent log claims all blocks that contain immediate write data 748 * so that the SPA knows they're in use. 749 * 750 * All claims *must* be resolved in the first txg -- before the SPA 751 * starts allocating blocks -- so that nothing is allocated twice. 752 * If txg == 0 we just verify that the block is claimable. 753 */ 754 ASSERT3U(spa->spa_uberblock.ub_rootbp.blk_birth, <, spa_first_txg(spa)); 755 ASSERT(txg == spa_first_txg(spa) || txg == 0); 756 ASSERT(!BP_GET_DEDUP(bp) || !spa_writeable(spa)); /* zdb(1M) */ 757 758 zio = zio_create(pio, spa, txg, bp, NULL, BP_GET_PSIZE(bp), 759 done, private, ZIO_TYPE_CLAIM, ZIO_PRIORITY_NOW, flags, 760 NULL, 0, NULL, ZIO_STAGE_OPEN, ZIO_CLAIM_PIPELINE); 761 762 return (zio); 763 } 764 765 zio_t * 766 zio_ioctl(zio_t *pio, spa_t *spa, vdev_t *vd, int cmd, 767 zio_done_func_t *done, void *private, enum zio_flag flags) 768 { 769 zio_t *zio; 770 int c; 771 772 if (vd->vdev_children == 0) { 773 zio = zio_create(pio, spa, 0, NULL, NULL, 0, done, private, 774 ZIO_TYPE_IOCTL, ZIO_PRIORITY_NOW, flags, vd, 0, NULL, 775 ZIO_STAGE_OPEN, ZIO_IOCTL_PIPELINE); 776 777 zio->io_cmd = cmd; 778 } else { 779 zio = zio_null(pio, spa, NULL, NULL, NULL, flags); 780 781 for (c = 0; c < vd->vdev_children; c++) 782 zio_nowait(zio_ioctl(zio, spa, vd->vdev_child[c], cmd, 783 done, private, flags)); 784 } 785 786 return (zio); 787 } 788 789 zio_t * 790 zio_read_phys(zio_t *pio, vdev_t *vd, uint64_t offset, uint64_t size, 791 void *data, int checksum, zio_done_func_t *done, void *private, 792 zio_priority_t priority, enum zio_flag flags, boolean_t labels) 793 { 794 zio_t *zio; 795 796 ASSERT(vd->vdev_children == 0); 797 ASSERT(!labels || offset + size <= VDEV_LABEL_START_SIZE || 798 offset >= vd->vdev_psize - VDEV_LABEL_END_SIZE); 799 ASSERT3U(offset + size, <=, vd->vdev_psize); 800 801 zio = zio_create(pio, vd->vdev_spa, 0, NULL, data, size, done, private, 802 ZIO_TYPE_READ, priority, flags, vd, offset, NULL, 803 ZIO_STAGE_OPEN, ZIO_READ_PHYS_PIPELINE); 804 805 zio->io_prop.zp_checksum = checksum; 806 807 return (zio); 808 } 809 810 zio_t * 811 zio_write_phys(zio_t *pio, vdev_t *vd, uint64_t offset, uint64_t size, 812 void *data, int checksum, zio_done_func_t *done, void *private, 813 zio_priority_t priority, enum zio_flag flags, boolean_t labels) 814 { 815 zio_t *zio; 816 817 ASSERT(vd->vdev_children == 0); 818 ASSERT(!labels || offset + size <= VDEV_LABEL_START_SIZE || 819 offset >= vd->vdev_psize - VDEV_LABEL_END_SIZE); 820 ASSERT3U(offset + size, <=, vd->vdev_psize); 821 822 zio = zio_create(pio, vd->vdev_spa, 0, NULL, data, size, done, private, 823 ZIO_TYPE_WRITE, priority, flags, vd, offset, NULL, 824 ZIO_STAGE_OPEN, ZIO_WRITE_PHYS_PIPELINE); 825 826 zio->io_prop.zp_checksum = checksum; 827 828 if (zio_checksum_table[checksum].ci_eck) { 829 /* 830 * zec checksums are necessarily destructive -- they modify 831 * the end of the write buffer to hold the verifier/checksum. 832 * Therefore, we must make a local copy in case the data is 833 * being written to multiple places in parallel. 834 */ 835 void *wbuf = zio_buf_alloc(size); 836 bcopy(data, wbuf, size); 837 zio_push_transform(zio, wbuf, size, size, NULL); 838 } 839 840 return (zio); 841 } 842 843 /* 844 * Create a child I/O to do some work for us. 845 */ 846 zio_t * 847 zio_vdev_child_io(zio_t *pio, blkptr_t *bp, vdev_t *vd, uint64_t offset, 848 void *data, uint64_t size, int type, zio_priority_t priority, 849 enum zio_flag flags, zio_done_func_t *done, void *private) 850 { 851 enum zio_stage pipeline = ZIO_VDEV_CHILD_PIPELINE; 852 zio_t *zio; 853 854 ASSERT(vd->vdev_parent == 855 (pio->io_vd ? pio->io_vd : pio->io_spa->spa_root_vdev)); 856 857 if (type == ZIO_TYPE_READ && bp != NULL) { 858 /* 859 * If we have the bp, then the child should perform the 860 * checksum and the parent need not. This pushes error 861 * detection as close to the leaves as possible and 862 * eliminates redundant checksums in the interior nodes. 863 */ 864 pipeline |= ZIO_STAGE_CHECKSUM_VERIFY; 865 pio->io_pipeline &= ~ZIO_STAGE_CHECKSUM_VERIFY; 866 } 867 868 if (vd->vdev_children == 0) 869 offset += VDEV_LABEL_START_SIZE; 870 871 flags |= ZIO_VDEV_CHILD_FLAGS(pio) | ZIO_FLAG_DONT_PROPAGATE; 872 873 /* 874 * If we've decided to do a repair, the write is not speculative -- 875 * even if the original read was. 876 */ 877 if (flags & ZIO_FLAG_IO_REPAIR) 878 flags &= ~ZIO_FLAG_SPECULATIVE; 879 880 zio = zio_create(pio, pio->io_spa, pio->io_txg, bp, data, size, 881 done, private, type, priority, flags, vd, offset, &pio->io_bookmark, 882 ZIO_STAGE_VDEV_IO_START >> 1, pipeline); 883 884 zio->io_physdone = pio->io_physdone; 885 if (vd->vdev_ops->vdev_op_leaf && zio->io_logical != NULL) 886 zio->io_logical->io_phys_children++; 887 888 return (zio); 889 } 890 891 zio_t * 892 zio_vdev_delegated_io(vdev_t *vd, uint64_t offset, void *data, uint64_t size, 893 int type, zio_priority_t priority, enum zio_flag flags, 894 zio_done_func_t *done, void *private) 895 { 896 zio_t *zio; 897 898 ASSERT(vd->vdev_ops->vdev_op_leaf); 899 900 zio = zio_create(NULL, vd->vdev_spa, 0, NULL, 901 data, size, done, private, type, priority, 902 flags | ZIO_FLAG_CANFAIL | ZIO_FLAG_DONT_RETRY | ZIO_FLAG_DELEGATED, 903 vd, offset, NULL, 904 ZIO_STAGE_VDEV_IO_START >> 1, ZIO_VDEV_CHILD_PIPELINE); 905 906 return (zio); 907 } 908 909 void 910 zio_flush(zio_t *zio, vdev_t *vd) 911 { 912 zio_nowait(zio_ioctl(zio, zio->io_spa, vd, DKIOCFLUSHWRITECACHE, 913 NULL, NULL, 914 ZIO_FLAG_CANFAIL | ZIO_FLAG_DONT_PROPAGATE | ZIO_FLAG_DONT_RETRY)); 915 } 916 917 void 918 zio_shrink(zio_t *zio, uint64_t size) 919 { 920 ASSERT(zio->io_executor == NULL); 921 ASSERT(zio->io_orig_size == zio->io_size); 922 ASSERT(size <= zio->io_size); 923 924 /* 925 * We don't shrink for raidz because of problems with the 926 * reconstruction when reading back less than the block size. 927 * Note, BP_IS_RAIDZ() assumes no compression. 928 */ 929 ASSERT(BP_GET_COMPRESS(zio->io_bp) == ZIO_COMPRESS_OFF); 930 if (!BP_IS_RAIDZ(zio->io_bp)) 931 zio->io_orig_size = zio->io_size = size; 932 } 933 934 /* 935 * ========================================================================== 936 * Prepare to read and write logical blocks 937 * ========================================================================== 938 */ 939 940 static int 941 zio_read_bp_init(zio_t *zio) 942 { 943 blkptr_t *bp = zio->io_bp; 944 945 if (BP_GET_COMPRESS(bp) != ZIO_COMPRESS_OFF && 946 zio->io_child_type == ZIO_CHILD_LOGICAL && 947 !(zio->io_flags & ZIO_FLAG_RAW)) { 948 uint64_t psize = BP_GET_PSIZE(bp); 949 void *cbuf = zio_buf_alloc(psize); 950 951 zio_push_transform(zio, cbuf, psize, psize, zio_decompress); 952 } 953 954 if (!DMU_OT_IS_METADATA(BP_GET_TYPE(bp)) && BP_GET_LEVEL(bp) == 0) 955 zio->io_flags |= ZIO_FLAG_DONT_CACHE; 956 957 if (BP_GET_TYPE(bp) == DMU_OT_DDT_ZAP) 958 zio->io_flags |= ZIO_FLAG_DONT_CACHE; 959 960 if (BP_GET_DEDUP(bp) && zio->io_child_type == ZIO_CHILD_LOGICAL) 961 zio->io_pipeline = ZIO_DDT_READ_PIPELINE; 962 963 return (ZIO_PIPELINE_CONTINUE); 964 } 965 966 static int 967 zio_write_bp_init(zio_t *zio) 968 { 969 spa_t *spa = zio->io_spa; 970 zio_prop_t *zp = &zio->io_prop; 971 enum zio_compress compress = zp->zp_compress; 972 blkptr_t *bp = zio->io_bp; 973 uint64_t lsize = zio->io_size; 974 uint64_t psize = lsize; 975 int pass = 1; 976 977 /* 978 * If our children haven't all reached the ready stage, 979 * wait for them and then repeat this pipeline stage. 980 */ 981 if (zio_wait_for_children(zio, ZIO_CHILD_GANG, ZIO_WAIT_READY) || 982 zio_wait_for_children(zio, ZIO_CHILD_LOGICAL, ZIO_WAIT_READY)) 983 return (ZIO_PIPELINE_STOP); 984 985 if (!IO_IS_ALLOCATING(zio)) 986 return (ZIO_PIPELINE_CONTINUE); 987 988 ASSERT(zio->io_child_type != ZIO_CHILD_DDT); 989 990 if (zio->io_bp_override) { 991 ASSERT(bp->blk_birth != zio->io_txg); 992 ASSERT(BP_GET_DEDUP(zio->io_bp_override) == 0); 993 994 *bp = *zio->io_bp_override; 995 zio->io_pipeline = ZIO_INTERLOCK_PIPELINE; 996 997 /* 998 * If we've been overridden and nopwrite is set then 999 * set the flag accordingly to indicate that a nopwrite 1000 * has already occurred. 1001 */ 1002 if (!BP_IS_HOLE(bp) && zp->zp_nopwrite) { 1003 ASSERT(!zp->zp_dedup); 1004 zio->io_flags |= ZIO_FLAG_NOPWRITE; 1005 return (ZIO_PIPELINE_CONTINUE); 1006 } 1007 1008 ASSERT(!zp->zp_nopwrite); 1009 1010 if (BP_IS_HOLE(bp) || !zp->zp_dedup) 1011 return (ZIO_PIPELINE_CONTINUE); 1012 1013 ASSERT(zio_checksum_table[zp->zp_checksum].ci_dedup || 1014 zp->zp_dedup_verify); 1015 1016 if (BP_GET_CHECKSUM(bp) == zp->zp_checksum) { 1017 BP_SET_DEDUP(bp, 1); 1018 zio->io_pipeline |= ZIO_STAGE_DDT_WRITE; 1019 return (ZIO_PIPELINE_CONTINUE); 1020 } 1021 zio->io_bp_override = NULL; 1022 BP_ZERO(bp); 1023 } 1024 1025 if (bp->blk_birth == zio->io_txg) { 1026 /* 1027 * We're rewriting an existing block, which means we're 1028 * working on behalf of spa_sync(). For spa_sync() to 1029 * converge, it must eventually be the case that we don't 1030 * have to allocate new blocks. But compression changes 1031 * the blocksize, which forces a reallocate, and makes 1032 * convergence take longer. Therefore, after the first 1033 * few passes, stop compressing to ensure convergence. 1034 */ 1035 pass = spa_sync_pass(spa); 1036 1037 ASSERT(zio->io_txg == spa_syncing_txg(spa)); 1038 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL); 1039 ASSERT(!BP_GET_DEDUP(bp)); 1040 1041 if (pass >= zfs_sync_pass_dont_compress) 1042 compress = ZIO_COMPRESS_OFF; 1043 1044 /* Make sure someone doesn't change their mind on overwrites */ 1045 ASSERT(MIN(zp->zp_copies + BP_IS_GANG(bp), 1046 spa_max_replication(spa)) == BP_GET_NDVAS(bp)); 1047 } 1048 1049 if (compress != ZIO_COMPRESS_OFF) { 1050 void *cbuf = zio_buf_alloc(lsize); 1051 psize = zio_compress_data(compress, zio->io_data, cbuf, lsize); 1052 if (psize == 0 || psize == lsize) { 1053 compress = ZIO_COMPRESS_OFF; 1054 zio_buf_free(cbuf, lsize); 1055 } else { 1056 ASSERT(psize < lsize); 1057 zio_push_transform(zio, cbuf, psize, lsize, NULL); 1058 } 1059 } 1060 1061 /* 1062 * The final pass of spa_sync() must be all rewrites, but the first 1063 * few passes offer a trade-off: allocating blocks defers convergence, 1064 * but newly allocated blocks are sequential, so they can be written 1065 * to disk faster. Therefore, we allow the first few passes of 1066 * spa_sync() to allocate new blocks, but force rewrites after that. 1067 * There should only be a handful of blocks after pass 1 in any case. 1068 */ 1069 if (bp->blk_birth == zio->io_txg && BP_GET_PSIZE(bp) == psize && 1070 pass >= zfs_sync_pass_rewrite) { 1071 ASSERT(psize != 0); 1072 enum zio_stage gang_stages = zio->io_pipeline & ZIO_GANG_STAGES; 1073 zio->io_pipeline = ZIO_REWRITE_PIPELINE | gang_stages; 1074 zio->io_flags |= ZIO_FLAG_IO_REWRITE; 1075 } else { 1076 BP_ZERO(bp); 1077 zio->io_pipeline = ZIO_WRITE_PIPELINE; 1078 } 1079 1080 if (psize == 0) { 1081 zio->io_pipeline = ZIO_INTERLOCK_PIPELINE; 1082 } else { 1083 ASSERT(zp->zp_checksum != ZIO_CHECKSUM_GANG_HEADER); 1084 BP_SET_LSIZE(bp, lsize); 1085 BP_SET_PSIZE(bp, psize); 1086 BP_SET_COMPRESS(bp, compress); 1087 BP_SET_CHECKSUM(bp, zp->zp_checksum); 1088 BP_SET_TYPE(bp, zp->zp_type); 1089 BP_SET_LEVEL(bp, zp->zp_level); 1090 BP_SET_DEDUP(bp, zp->zp_dedup); 1091 BP_SET_BYTEORDER(bp, ZFS_HOST_BYTEORDER); 1092 if (zp->zp_dedup) { 1093 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL); 1094 ASSERT(!(zio->io_flags & ZIO_FLAG_IO_REWRITE)); 1095 zio->io_pipeline = ZIO_DDT_WRITE_PIPELINE; 1096 } 1097 if (zp->zp_nopwrite) { 1098 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL); 1099 ASSERT(!(zio->io_flags & ZIO_FLAG_IO_REWRITE)); 1100 zio->io_pipeline |= ZIO_STAGE_NOP_WRITE; 1101 } 1102 } 1103 1104 return (ZIO_PIPELINE_CONTINUE); 1105 } 1106 1107 static int 1108 zio_free_bp_init(zio_t *zio) 1109 { 1110 blkptr_t *bp = zio->io_bp; 1111 1112 if (zio->io_child_type == ZIO_CHILD_LOGICAL) { 1113 if (BP_GET_DEDUP(bp)) 1114 zio->io_pipeline = ZIO_DDT_FREE_PIPELINE; 1115 } 1116 1117 return (ZIO_PIPELINE_CONTINUE); 1118 } 1119 1120 /* 1121 * ========================================================================== 1122 * Execute the I/O pipeline 1123 * ========================================================================== 1124 */ 1125 1126 static void 1127 zio_taskq_dispatch(zio_t *zio, zio_taskq_type_t q, boolean_t cutinline) 1128 { 1129 spa_t *spa = zio->io_spa; 1130 zio_type_t t = zio->io_type; 1131 int flags = (cutinline ? TQ_FRONT : 0); 1132 1133 /* 1134 * If we're a config writer or a probe, the normal issue and 1135 * interrupt threads may all be blocked waiting for the config lock. 1136 * In this case, select the otherwise-unused taskq for ZIO_TYPE_NULL. 1137 */ 1138 if (zio->io_flags & (ZIO_FLAG_CONFIG_WRITER | ZIO_FLAG_PROBE)) 1139 t = ZIO_TYPE_NULL; 1140 1141 /* 1142 * A similar issue exists for the L2ARC write thread until L2ARC 2.0. 1143 */ 1144 if (t == ZIO_TYPE_WRITE && zio->io_vd && zio->io_vd->vdev_aux) 1145 t = ZIO_TYPE_NULL; 1146 1147 /* 1148 * If this is a high priority I/O, then use the high priority taskq if 1149 * available. 1150 */ 1151 if (zio->io_priority == ZIO_PRIORITY_NOW && 1152 spa->spa_zio_taskq[t][q + 1].stqs_count != 0) 1153 q++; 1154 1155 ASSERT3U(q, <, ZIO_TASKQ_TYPES); 1156 1157 /* 1158 * NB: We are assuming that the zio can only be dispatched 1159 * to a single taskq at a time. It would be a grievous error 1160 * to dispatch the zio to another taskq at the same time. 1161 */ 1162 ASSERT(zio->io_tqent.tqent_next == NULL); 1163 spa_taskq_dispatch_ent(spa, t, q, (task_func_t *)zio_execute, zio, 1164 flags, &zio->io_tqent); 1165 } 1166 1167 static boolean_t 1168 zio_taskq_member(zio_t *zio, zio_taskq_type_t q) 1169 { 1170 kthread_t *executor = zio->io_executor; 1171 spa_t *spa = zio->io_spa; 1172 1173 for (zio_type_t t = 0; t < ZIO_TYPES; t++) { 1174 spa_taskqs_t *tqs = &spa->spa_zio_taskq[t][q]; 1175 uint_t i; 1176 for (i = 0; i < tqs->stqs_count; i++) { 1177 if (taskq_member(tqs->stqs_taskq[i], executor)) 1178 return (B_TRUE); 1179 } 1180 } 1181 1182 return (B_FALSE); 1183 } 1184 1185 static int 1186 zio_issue_async(zio_t *zio) 1187 { 1188 zio_taskq_dispatch(zio, ZIO_TASKQ_ISSUE, B_FALSE); 1189 1190 return (ZIO_PIPELINE_STOP); 1191 } 1192 1193 void 1194 zio_interrupt(zio_t *zio) 1195 { 1196 zio_taskq_dispatch(zio, ZIO_TASKQ_INTERRUPT, B_FALSE); 1197 } 1198 1199 /* 1200 * Execute the I/O pipeline until one of the following occurs: 1201 * 1202 * (1) the I/O completes 1203 * (2) the pipeline stalls waiting for dependent child I/Os 1204 * (3) the I/O issues, so we're waiting for an I/O completion interrupt 1205 * (4) the I/O is delegated by vdev-level caching or aggregation 1206 * (5) the I/O is deferred due to vdev-level queueing 1207 * (6) the I/O is handed off to another thread. 1208 * 1209 * In all cases, the pipeline stops whenever there's no CPU work; it never 1210 * burns a thread in cv_wait(). 1211 * 1212 * There's no locking on io_stage because there's no legitimate way 1213 * for multiple threads to be attempting to process the same I/O. 1214 */ 1215 static zio_pipe_stage_t *zio_pipeline[]; 1216 1217 void 1218 zio_execute(zio_t *zio) 1219 { 1220 zio->io_executor = curthread; 1221 1222 while (zio->io_stage < ZIO_STAGE_DONE) { 1223 enum zio_stage pipeline = zio->io_pipeline; 1224 enum zio_stage stage = zio->io_stage; 1225 int rv; 1226 1227 ASSERT(!MUTEX_HELD(&zio->io_lock)); 1228 ASSERT(ISP2(stage)); 1229 ASSERT(zio->io_stall == NULL); 1230 1231 do { 1232 stage <<= 1; 1233 } while ((stage & pipeline) == 0); 1234 1235 ASSERT(stage <= ZIO_STAGE_DONE); 1236 1237 /* 1238 * If we are in interrupt context and this pipeline stage 1239 * will grab a config lock that is held across I/O, 1240 * or may wait for an I/O that needs an interrupt thread 1241 * to complete, issue async to avoid deadlock. 1242 * 1243 * For VDEV_IO_START, we cut in line so that the io will 1244 * be sent to disk promptly. 1245 */ 1246 if ((stage & ZIO_BLOCKING_STAGES) && zio->io_vd == NULL && 1247 zio_taskq_member(zio, ZIO_TASKQ_INTERRUPT)) { 1248 boolean_t cut = (stage == ZIO_STAGE_VDEV_IO_START) ? 1249 zio_requeue_io_start_cut_in_line : B_FALSE; 1250 zio_taskq_dispatch(zio, ZIO_TASKQ_ISSUE, cut); 1251 return; 1252 } 1253 1254 zio->io_stage = stage; 1255 rv = zio_pipeline[highbit(stage) - 1](zio); 1256 1257 if (rv == ZIO_PIPELINE_STOP) 1258 return; 1259 1260 ASSERT(rv == ZIO_PIPELINE_CONTINUE); 1261 } 1262 } 1263 1264 /* 1265 * ========================================================================== 1266 * Initiate I/O, either sync or async 1267 * ========================================================================== 1268 */ 1269 int 1270 zio_wait(zio_t *zio) 1271 { 1272 int error; 1273 1274 ASSERT(zio->io_stage == ZIO_STAGE_OPEN); 1275 ASSERT(zio->io_executor == NULL); 1276 1277 zio->io_waiter = curthread; 1278 1279 zio_execute(zio); 1280 1281 mutex_enter(&zio->io_lock); 1282 while (zio->io_executor != NULL) 1283 cv_wait(&zio->io_cv, &zio->io_lock); 1284 mutex_exit(&zio->io_lock); 1285 1286 error = zio->io_error; 1287 zio_destroy(zio); 1288 1289 return (error); 1290 } 1291 1292 void 1293 zio_nowait(zio_t *zio) 1294 { 1295 ASSERT(zio->io_executor == NULL); 1296 1297 if (zio->io_child_type == ZIO_CHILD_LOGICAL && 1298 zio_unique_parent(zio) == NULL) { 1299 /* 1300 * This is a logical async I/O with no parent to wait for it. 1301 * We add it to the spa_async_root_zio "Godfather" I/O which 1302 * will ensure they complete prior to unloading the pool. 1303 */ 1304 spa_t *spa = zio->io_spa; 1305 1306 zio_add_child(spa->spa_async_zio_root, zio); 1307 } 1308 1309 zio_execute(zio); 1310 } 1311 1312 /* 1313 * ========================================================================== 1314 * Reexecute or suspend/resume failed I/O 1315 * ========================================================================== 1316 */ 1317 1318 static void 1319 zio_reexecute(zio_t *pio) 1320 { 1321 zio_t *cio, *cio_next; 1322 1323 ASSERT(pio->io_child_type == ZIO_CHILD_LOGICAL); 1324 ASSERT(pio->io_orig_stage == ZIO_STAGE_OPEN); 1325 ASSERT(pio->io_gang_leader == NULL); 1326 ASSERT(pio->io_gang_tree == NULL); 1327 1328 pio->io_flags = pio->io_orig_flags; 1329 pio->io_stage = pio->io_orig_stage; 1330 pio->io_pipeline = pio->io_orig_pipeline; 1331 pio->io_reexecute = 0; 1332 pio->io_flags |= ZIO_FLAG_REEXECUTED; 1333 pio->io_error = 0; 1334 for (int w = 0; w < ZIO_WAIT_TYPES; w++) 1335 pio->io_state[w] = 0; 1336 for (int c = 0; c < ZIO_CHILD_TYPES; c++) 1337 pio->io_child_error[c] = 0; 1338 1339 if (IO_IS_ALLOCATING(pio)) 1340 BP_ZERO(pio->io_bp); 1341 1342 /* 1343 * As we reexecute pio's children, new children could be created. 1344 * New children go to the head of pio's io_child_list, however, 1345 * so we will (correctly) not reexecute them. The key is that 1346 * the remainder of pio's io_child_list, from 'cio_next' onward, 1347 * cannot be affected by any side effects of reexecuting 'cio'. 1348 */ 1349 for (cio = zio_walk_children(pio); cio != NULL; cio = cio_next) { 1350 cio_next = zio_walk_children(pio); 1351 mutex_enter(&pio->io_lock); 1352 for (int w = 0; w < ZIO_WAIT_TYPES; w++) 1353 pio->io_children[cio->io_child_type][w]++; 1354 mutex_exit(&pio->io_lock); 1355 zio_reexecute(cio); 1356 } 1357 1358 /* 1359 * Now that all children have been reexecuted, execute the parent. 1360 * We don't reexecute "The Godfather" I/O here as it's the 1361 * responsibility of the caller to wait on him. 1362 */ 1363 if (!(pio->io_flags & ZIO_FLAG_GODFATHER)) 1364 zio_execute(pio); 1365 } 1366 1367 void 1368 zio_suspend(spa_t *spa, zio_t *zio) 1369 { 1370 if (spa_get_failmode(spa) == ZIO_FAILURE_MODE_PANIC) 1371 fm_panic("Pool '%s' has encountered an uncorrectable I/O " 1372 "failure and the failure mode property for this pool " 1373 "is set to panic.", spa_name(spa)); 1374 1375 zfs_ereport_post(FM_EREPORT_ZFS_IO_FAILURE, spa, NULL, NULL, 0, 0); 1376 1377 mutex_enter(&spa->spa_suspend_lock); 1378 1379 if (spa->spa_suspend_zio_root == NULL) 1380 spa->spa_suspend_zio_root = zio_root(spa, NULL, NULL, 1381 ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE | 1382 ZIO_FLAG_GODFATHER); 1383 1384 spa->spa_suspended = B_TRUE; 1385 1386 if (zio != NULL) { 1387 ASSERT(!(zio->io_flags & ZIO_FLAG_GODFATHER)); 1388 ASSERT(zio != spa->spa_suspend_zio_root); 1389 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL); 1390 ASSERT(zio_unique_parent(zio) == NULL); 1391 ASSERT(zio->io_stage == ZIO_STAGE_DONE); 1392 zio_add_child(spa->spa_suspend_zio_root, zio); 1393 } 1394 1395 mutex_exit(&spa->spa_suspend_lock); 1396 } 1397 1398 int 1399 zio_resume(spa_t *spa) 1400 { 1401 zio_t *pio; 1402 1403 /* 1404 * Reexecute all previously suspended i/o. 1405 */ 1406 mutex_enter(&spa->spa_suspend_lock); 1407 spa->spa_suspended = B_FALSE; 1408 cv_broadcast(&spa->spa_suspend_cv); 1409 pio = spa->spa_suspend_zio_root; 1410 spa->spa_suspend_zio_root = NULL; 1411 mutex_exit(&spa->spa_suspend_lock); 1412 1413 if (pio == NULL) 1414 return (0); 1415 1416 zio_reexecute(pio); 1417 return (zio_wait(pio)); 1418 } 1419 1420 void 1421 zio_resume_wait(spa_t *spa) 1422 { 1423 mutex_enter(&spa->spa_suspend_lock); 1424 while (spa_suspended(spa)) 1425 cv_wait(&spa->spa_suspend_cv, &spa->spa_suspend_lock); 1426 mutex_exit(&spa->spa_suspend_lock); 1427 } 1428 1429 /* 1430 * ========================================================================== 1431 * Gang blocks. 1432 * 1433 * A gang block is a collection of small blocks that looks to the DMU 1434 * like one large block. When zio_dva_allocate() cannot find a block 1435 * of the requested size, due to either severe fragmentation or the pool 1436 * being nearly full, it calls zio_write_gang_block() to construct the 1437 * block from smaller fragments. 1438 * 1439 * A gang block consists of a gang header (zio_gbh_phys_t) and up to 1440 * three (SPA_GBH_NBLKPTRS) gang members. The gang header is just like 1441 * an indirect block: it's an array of block pointers. It consumes 1442 * only one sector and hence is allocatable regardless of fragmentation. 1443 * The gang header's bps point to its gang members, which hold the data. 1444 * 1445 * Gang blocks are self-checksumming, using the bp's <vdev, offset, txg> 1446 * as the verifier to ensure uniqueness of the SHA256 checksum. 1447 * Critically, the gang block bp's blk_cksum is the checksum of the data, 1448 * not the gang header. This ensures that data block signatures (needed for 1449 * deduplication) are independent of how the block is physically stored. 1450 * 1451 * Gang blocks can be nested: a gang member may itself be a gang block. 1452 * Thus every gang block is a tree in which root and all interior nodes are 1453 * gang headers, and the leaves are normal blocks that contain user data. 1454 * The root of the gang tree is called the gang leader. 1455 * 1456 * To perform any operation (read, rewrite, free, claim) on a gang block, 1457 * zio_gang_assemble() first assembles the gang tree (minus data leaves) 1458 * in the io_gang_tree field of the original logical i/o by recursively 1459 * reading the gang leader and all gang headers below it. This yields 1460 * an in-core tree containing the contents of every gang header and the 1461 * bps for every constituent of the gang block. 1462 * 1463 * With the gang tree now assembled, zio_gang_issue() just walks the gang tree 1464 * and invokes a callback on each bp. To free a gang block, zio_gang_issue() 1465 * calls zio_free_gang() -- a trivial wrapper around zio_free() -- for each bp. 1466 * zio_claim_gang() provides a similarly trivial wrapper for zio_claim(). 1467 * zio_read_gang() is a wrapper around zio_read() that omits reading gang 1468 * headers, since we already have those in io_gang_tree. zio_rewrite_gang() 1469 * performs a zio_rewrite() of the data or, for gang headers, a zio_rewrite() 1470 * of the gang header plus zio_checksum_compute() of the data to update the 1471 * gang header's blk_cksum as described above. 1472 * 1473 * The two-phase assemble/issue model solves the problem of partial failure -- 1474 * what if you'd freed part of a gang block but then couldn't read the 1475 * gang header for another part? Assembling the entire gang tree first 1476 * ensures that all the necessary gang header I/O has succeeded before 1477 * starting the actual work of free, claim, or write. Once the gang tree 1478 * is assembled, free and claim are in-memory operations that cannot fail. 1479 * 1480 * In the event that a gang write fails, zio_dva_unallocate() walks the 1481 * gang tree to immediately free (i.e. insert back into the space map) 1482 * everything we've allocated. This ensures that we don't get ENOSPC 1483 * errors during repeated suspend/resume cycles due to a flaky device. 1484 * 1485 * Gang rewrites only happen during sync-to-convergence. If we can't assemble 1486 * the gang tree, we won't modify the block, so we can safely defer the free 1487 * (knowing that the block is still intact). If we *can* assemble the gang 1488 * tree, then even if some of the rewrites fail, zio_dva_unallocate() will free 1489 * each constituent bp and we can allocate a new block on the next sync pass. 1490 * 1491 * In all cases, the gang tree allows complete recovery from partial failure. 1492 * ========================================================================== 1493 */ 1494 1495 static zio_t * 1496 zio_read_gang(zio_t *pio, blkptr_t *bp, zio_gang_node_t *gn, void *data) 1497 { 1498 if (gn != NULL) 1499 return (pio); 1500 1501 return (zio_read(pio, pio->io_spa, bp, data, BP_GET_PSIZE(bp), 1502 NULL, NULL, pio->io_priority, ZIO_GANG_CHILD_FLAGS(pio), 1503 &pio->io_bookmark)); 1504 } 1505 1506 zio_t * 1507 zio_rewrite_gang(zio_t *pio, blkptr_t *bp, zio_gang_node_t *gn, void *data) 1508 { 1509 zio_t *zio; 1510 1511 if (gn != NULL) { 1512 zio = zio_rewrite(pio, pio->io_spa, pio->io_txg, bp, 1513 gn->gn_gbh, SPA_GANGBLOCKSIZE, NULL, NULL, pio->io_priority, 1514 ZIO_GANG_CHILD_FLAGS(pio), &pio->io_bookmark); 1515 /* 1516 * As we rewrite each gang header, the pipeline will compute 1517 * a new gang block header checksum for it; but no one will 1518 * compute a new data checksum, so we do that here. The one 1519 * exception is the gang leader: the pipeline already computed 1520 * its data checksum because that stage precedes gang assembly. 1521 * (Presently, nothing actually uses interior data checksums; 1522 * this is just good hygiene.) 1523 */ 1524 if (gn != pio->io_gang_leader->io_gang_tree) { 1525 zio_checksum_compute(zio, BP_GET_CHECKSUM(bp), 1526 data, BP_GET_PSIZE(bp)); 1527 } 1528 /* 1529 * If we are here to damage data for testing purposes, 1530 * leave the GBH alone so that we can detect the damage. 1531 */ 1532 if (pio->io_gang_leader->io_flags & ZIO_FLAG_INDUCE_DAMAGE) 1533 zio->io_pipeline &= ~ZIO_VDEV_IO_STAGES; 1534 } else { 1535 zio = zio_rewrite(pio, pio->io_spa, pio->io_txg, bp, 1536 data, BP_GET_PSIZE(bp), NULL, NULL, pio->io_priority, 1537 ZIO_GANG_CHILD_FLAGS(pio), &pio->io_bookmark); 1538 } 1539 1540 return (zio); 1541 } 1542 1543 /* ARGSUSED */ 1544 zio_t * 1545 zio_free_gang(zio_t *pio, blkptr_t *bp, zio_gang_node_t *gn, void *data) 1546 { 1547 return (zio_free_sync(pio, pio->io_spa, pio->io_txg, bp, 1548 ZIO_GANG_CHILD_FLAGS(pio))); 1549 } 1550 1551 /* ARGSUSED */ 1552 zio_t * 1553 zio_claim_gang(zio_t *pio, blkptr_t *bp, zio_gang_node_t *gn, void *data) 1554 { 1555 return (zio_claim(pio, pio->io_spa, pio->io_txg, bp, 1556 NULL, NULL, ZIO_GANG_CHILD_FLAGS(pio))); 1557 } 1558 1559 static zio_gang_issue_func_t *zio_gang_issue_func[ZIO_TYPES] = { 1560 NULL, 1561 zio_read_gang, 1562 zio_rewrite_gang, 1563 zio_free_gang, 1564 zio_claim_gang, 1565 NULL 1566 }; 1567 1568 static void zio_gang_tree_assemble_done(zio_t *zio); 1569 1570 static zio_gang_node_t * 1571 zio_gang_node_alloc(zio_gang_node_t **gnpp) 1572 { 1573 zio_gang_node_t *gn; 1574 1575 ASSERT(*gnpp == NULL); 1576 1577 gn = kmem_zalloc(sizeof (*gn), KM_SLEEP); 1578 gn->gn_gbh = zio_buf_alloc(SPA_GANGBLOCKSIZE); 1579 *gnpp = gn; 1580 1581 return (gn); 1582 } 1583 1584 static void 1585 zio_gang_node_free(zio_gang_node_t **gnpp) 1586 { 1587 zio_gang_node_t *gn = *gnpp; 1588 1589 for (int g = 0; g < SPA_GBH_NBLKPTRS; g++) 1590 ASSERT(gn->gn_child[g] == NULL); 1591 1592 zio_buf_free(gn->gn_gbh, SPA_GANGBLOCKSIZE); 1593 kmem_free(gn, sizeof (*gn)); 1594 *gnpp = NULL; 1595 } 1596 1597 static void 1598 zio_gang_tree_free(zio_gang_node_t **gnpp) 1599 { 1600 zio_gang_node_t *gn = *gnpp; 1601 1602 if (gn == NULL) 1603 return; 1604 1605 for (int g = 0; g < SPA_GBH_NBLKPTRS; g++) 1606 zio_gang_tree_free(&gn->gn_child[g]); 1607 1608 zio_gang_node_free(gnpp); 1609 } 1610 1611 static void 1612 zio_gang_tree_assemble(zio_t *gio, blkptr_t *bp, zio_gang_node_t **gnpp) 1613 { 1614 zio_gang_node_t *gn = zio_gang_node_alloc(gnpp); 1615 1616 ASSERT(gio->io_gang_leader == gio); 1617 ASSERT(BP_IS_GANG(bp)); 1618 1619 zio_nowait(zio_read(gio, gio->io_spa, bp, gn->gn_gbh, 1620 SPA_GANGBLOCKSIZE, zio_gang_tree_assemble_done, gn, 1621 gio->io_priority, ZIO_GANG_CHILD_FLAGS(gio), &gio->io_bookmark)); 1622 } 1623 1624 static void 1625 zio_gang_tree_assemble_done(zio_t *zio) 1626 { 1627 zio_t *gio = zio->io_gang_leader; 1628 zio_gang_node_t *gn = zio->io_private; 1629 blkptr_t *bp = zio->io_bp; 1630 1631 ASSERT(gio == zio_unique_parent(zio)); 1632 ASSERT(zio->io_child_count == 0); 1633 1634 if (zio->io_error) 1635 return; 1636 1637 if (BP_SHOULD_BYTESWAP(bp)) 1638 byteswap_uint64_array(zio->io_data, zio->io_size); 1639 1640 ASSERT(zio->io_data == gn->gn_gbh); 1641 ASSERT(zio->io_size == SPA_GANGBLOCKSIZE); 1642 ASSERT(gn->gn_gbh->zg_tail.zec_magic == ZEC_MAGIC); 1643 1644 for (int g = 0; g < SPA_GBH_NBLKPTRS; g++) { 1645 blkptr_t *gbp = &gn->gn_gbh->zg_blkptr[g]; 1646 if (!BP_IS_GANG(gbp)) 1647 continue; 1648 zio_gang_tree_assemble(gio, gbp, &gn->gn_child[g]); 1649 } 1650 } 1651 1652 static void 1653 zio_gang_tree_issue(zio_t *pio, zio_gang_node_t *gn, blkptr_t *bp, void *data) 1654 { 1655 zio_t *gio = pio->io_gang_leader; 1656 zio_t *zio; 1657 1658 ASSERT(BP_IS_GANG(bp) == !!gn); 1659 ASSERT(BP_GET_CHECKSUM(bp) == BP_GET_CHECKSUM(gio->io_bp)); 1660 ASSERT(BP_GET_LSIZE(bp) == BP_GET_PSIZE(bp) || gn == gio->io_gang_tree); 1661 1662 /* 1663 * If you're a gang header, your data is in gn->gn_gbh. 1664 * If you're a gang member, your data is in 'data' and gn == NULL. 1665 */ 1666 zio = zio_gang_issue_func[gio->io_type](pio, bp, gn, data); 1667 1668 if (gn != NULL) { 1669 ASSERT(gn->gn_gbh->zg_tail.zec_magic == ZEC_MAGIC); 1670 1671 for (int g = 0; g < SPA_GBH_NBLKPTRS; g++) { 1672 blkptr_t *gbp = &gn->gn_gbh->zg_blkptr[g]; 1673 if (BP_IS_HOLE(gbp)) 1674 continue; 1675 zio_gang_tree_issue(zio, gn->gn_child[g], gbp, data); 1676 data = (char *)data + BP_GET_PSIZE(gbp); 1677 } 1678 } 1679 1680 if (gn == gio->io_gang_tree) 1681 ASSERT3P((char *)gio->io_data + gio->io_size, ==, data); 1682 1683 if (zio != pio) 1684 zio_nowait(zio); 1685 } 1686 1687 static int 1688 zio_gang_assemble(zio_t *zio) 1689 { 1690 blkptr_t *bp = zio->io_bp; 1691 1692 ASSERT(BP_IS_GANG(bp) && zio->io_gang_leader == NULL); 1693 ASSERT(zio->io_child_type > ZIO_CHILD_GANG); 1694 1695 zio->io_gang_leader = zio; 1696 1697 zio_gang_tree_assemble(zio, bp, &zio->io_gang_tree); 1698 1699 return (ZIO_PIPELINE_CONTINUE); 1700 } 1701 1702 static int 1703 zio_gang_issue(zio_t *zio) 1704 { 1705 blkptr_t *bp = zio->io_bp; 1706 1707 if (zio_wait_for_children(zio, ZIO_CHILD_GANG, ZIO_WAIT_DONE)) 1708 return (ZIO_PIPELINE_STOP); 1709 1710 ASSERT(BP_IS_GANG(bp) && zio->io_gang_leader == zio); 1711 ASSERT(zio->io_child_type > ZIO_CHILD_GANG); 1712 1713 if (zio->io_child_error[ZIO_CHILD_GANG] == 0) 1714 zio_gang_tree_issue(zio, zio->io_gang_tree, bp, zio->io_data); 1715 else 1716 zio_gang_tree_free(&zio->io_gang_tree); 1717 1718 zio->io_pipeline = ZIO_INTERLOCK_PIPELINE; 1719 1720 return (ZIO_PIPELINE_CONTINUE); 1721 } 1722 1723 static void 1724 zio_write_gang_member_ready(zio_t *zio) 1725 { 1726 zio_t *pio = zio_unique_parent(zio); 1727 zio_t *gio = zio->io_gang_leader; 1728 dva_t *cdva = zio->io_bp->blk_dva; 1729 dva_t *pdva = pio->io_bp->blk_dva; 1730 uint64_t asize; 1731 1732 if (BP_IS_HOLE(zio->io_bp)) 1733 return; 1734 1735 ASSERT(BP_IS_HOLE(&zio->io_bp_orig)); 1736 1737 ASSERT(zio->io_child_type == ZIO_CHILD_GANG); 1738 ASSERT3U(zio->io_prop.zp_copies, ==, gio->io_prop.zp_copies); 1739 ASSERT3U(zio->io_prop.zp_copies, <=, BP_GET_NDVAS(zio->io_bp)); 1740 ASSERT3U(pio->io_prop.zp_copies, <=, BP_GET_NDVAS(pio->io_bp)); 1741 ASSERT3U(BP_GET_NDVAS(zio->io_bp), <=, BP_GET_NDVAS(pio->io_bp)); 1742 1743 mutex_enter(&pio->io_lock); 1744 for (int d = 0; d < BP_GET_NDVAS(zio->io_bp); d++) { 1745 ASSERT(DVA_GET_GANG(&pdva[d])); 1746 asize = DVA_GET_ASIZE(&pdva[d]); 1747 asize += DVA_GET_ASIZE(&cdva[d]); 1748 DVA_SET_ASIZE(&pdva[d], asize); 1749 } 1750 mutex_exit(&pio->io_lock); 1751 } 1752 1753 static int 1754 zio_write_gang_block(zio_t *pio) 1755 { 1756 spa_t *spa = pio->io_spa; 1757 blkptr_t *bp = pio->io_bp; 1758 zio_t *gio = pio->io_gang_leader; 1759 zio_t *zio; 1760 zio_gang_node_t *gn, **gnpp; 1761 zio_gbh_phys_t *gbh; 1762 uint64_t txg = pio->io_txg; 1763 uint64_t resid = pio->io_size; 1764 uint64_t lsize; 1765 int copies = gio->io_prop.zp_copies; 1766 int gbh_copies = MIN(copies + 1, spa_max_replication(spa)); 1767 zio_prop_t zp; 1768 int error; 1769 1770 error = metaslab_alloc(spa, spa_normal_class(spa), SPA_GANGBLOCKSIZE, 1771 bp, gbh_copies, txg, pio == gio ? NULL : gio->io_bp, 1772 METASLAB_HINTBP_FAVOR | METASLAB_GANG_HEADER); 1773 if (error) { 1774 pio->io_error = error; 1775 return (ZIO_PIPELINE_CONTINUE); 1776 } 1777 1778 if (pio == gio) { 1779 gnpp = &gio->io_gang_tree; 1780 } else { 1781 gnpp = pio->io_private; 1782 ASSERT(pio->io_ready == zio_write_gang_member_ready); 1783 } 1784 1785 gn = zio_gang_node_alloc(gnpp); 1786 gbh = gn->gn_gbh; 1787 bzero(gbh, SPA_GANGBLOCKSIZE); 1788 1789 /* 1790 * Create the gang header. 1791 */ 1792 zio = zio_rewrite(pio, spa, txg, bp, gbh, SPA_GANGBLOCKSIZE, NULL, NULL, 1793 pio->io_priority, ZIO_GANG_CHILD_FLAGS(pio), &pio->io_bookmark); 1794 1795 /* 1796 * Create and nowait the gang children. 1797 */ 1798 for (int g = 0; resid != 0; resid -= lsize, g++) { 1799 lsize = P2ROUNDUP(resid / (SPA_GBH_NBLKPTRS - g), 1800 SPA_MINBLOCKSIZE); 1801 ASSERT(lsize >= SPA_MINBLOCKSIZE && lsize <= resid); 1802 1803 zp.zp_checksum = gio->io_prop.zp_checksum; 1804 zp.zp_compress = ZIO_COMPRESS_OFF; 1805 zp.zp_type = DMU_OT_NONE; 1806 zp.zp_level = 0; 1807 zp.zp_copies = gio->io_prop.zp_copies; 1808 zp.zp_dedup = B_FALSE; 1809 zp.zp_dedup_verify = B_FALSE; 1810 zp.zp_nopwrite = B_FALSE; 1811 1812 zio_nowait(zio_write(zio, spa, txg, &gbh->zg_blkptr[g], 1813 (char *)pio->io_data + (pio->io_size - resid), lsize, &zp, 1814 zio_write_gang_member_ready, NULL, NULL, &gn->gn_child[g], 1815 pio->io_priority, ZIO_GANG_CHILD_FLAGS(pio), 1816 &pio->io_bookmark)); 1817 } 1818 1819 /* 1820 * Set pio's pipeline to just wait for zio to finish. 1821 */ 1822 pio->io_pipeline = ZIO_INTERLOCK_PIPELINE; 1823 1824 zio_nowait(zio); 1825 1826 return (ZIO_PIPELINE_CONTINUE); 1827 } 1828 1829 /* 1830 * The zio_nop_write stage in the pipeline determines if allocating 1831 * a new bp is necessary. By leveraging a cryptographically secure checksum, 1832 * such as SHA256, we can compare the checksums of the new data and the old 1833 * to determine if allocating a new block is required. The nopwrite 1834 * feature can handle writes in either syncing or open context (i.e. zil 1835 * writes) and as a result is mutually exclusive with dedup. 1836 */ 1837 static int 1838 zio_nop_write(zio_t *zio) 1839 { 1840 blkptr_t *bp = zio->io_bp; 1841 blkptr_t *bp_orig = &zio->io_bp_orig; 1842 zio_prop_t *zp = &zio->io_prop; 1843 1844 ASSERT(BP_GET_LEVEL(bp) == 0); 1845 ASSERT(!(zio->io_flags & ZIO_FLAG_IO_REWRITE)); 1846 ASSERT(zp->zp_nopwrite); 1847 ASSERT(!zp->zp_dedup); 1848 ASSERT(zio->io_bp_override == NULL); 1849 ASSERT(IO_IS_ALLOCATING(zio)); 1850 1851 /* 1852 * Check to see if the original bp and the new bp have matching 1853 * characteristics (i.e. same checksum, compression algorithms, etc). 1854 * If they don't then just continue with the pipeline which will 1855 * allocate a new bp. 1856 */ 1857 if (BP_IS_HOLE(bp_orig) || 1858 !zio_checksum_table[BP_GET_CHECKSUM(bp)].ci_dedup || 1859 BP_GET_CHECKSUM(bp) != BP_GET_CHECKSUM(bp_orig) || 1860 BP_GET_COMPRESS(bp) != BP_GET_COMPRESS(bp_orig) || 1861 BP_GET_DEDUP(bp) != BP_GET_DEDUP(bp_orig) || 1862 zp->zp_copies != BP_GET_NDVAS(bp_orig)) 1863 return (ZIO_PIPELINE_CONTINUE); 1864 1865 /* 1866 * If the checksums match then reset the pipeline so that we 1867 * avoid allocating a new bp and issuing any I/O. 1868 */ 1869 if (ZIO_CHECKSUM_EQUAL(bp->blk_cksum, bp_orig->blk_cksum)) { 1870 ASSERT(zio_checksum_table[zp->zp_checksum].ci_dedup); 1871 ASSERT3U(BP_GET_PSIZE(bp), ==, BP_GET_PSIZE(bp_orig)); 1872 ASSERT3U(BP_GET_LSIZE(bp), ==, BP_GET_LSIZE(bp_orig)); 1873 ASSERT(zp->zp_compress != ZIO_COMPRESS_OFF); 1874 ASSERT(bcmp(&bp->blk_prop, &bp_orig->blk_prop, 1875 sizeof (uint64_t)) == 0); 1876 1877 *bp = *bp_orig; 1878 zio->io_pipeline = ZIO_INTERLOCK_PIPELINE; 1879 zio->io_flags |= ZIO_FLAG_NOPWRITE; 1880 } 1881 1882 return (ZIO_PIPELINE_CONTINUE); 1883 } 1884 1885 /* 1886 * ========================================================================== 1887 * Dedup 1888 * ========================================================================== 1889 */ 1890 static void 1891 zio_ddt_child_read_done(zio_t *zio) 1892 { 1893 blkptr_t *bp = zio->io_bp; 1894 ddt_entry_t *dde = zio->io_private; 1895 ddt_phys_t *ddp; 1896 zio_t *pio = zio_unique_parent(zio); 1897 1898 mutex_enter(&pio->io_lock); 1899 ddp = ddt_phys_select(dde, bp); 1900 if (zio->io_error == 0) 1901 ddt_phys_clear(ddp); /* this ddp doesn't need repair */ 1902 if (zio->io_error == 0 && dde->dde_repair_data == NULL) 1903 dde->dde_repair_data = zio->io_data; 1904 else 1905 zio_buf_free(zio->io_data, zio->io_size); 1906 mutex_exit(&pio->io_lock); 1907 } 1908 1909 static int 1910 zio_ddt_read_start(zio_t *zio) 1911 { 1912 blkptr_t *bp = zio->io_bp; 1913 1914 ASSERT(BP_GET_DEDUP(bp)); 1915 ASSERT(BP_GET_PSIZE(bp) == zio->io_size); 1916 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL); 1917 1918 if (zio->io_child_error[ZIO_CHILD_DDT]) { 1919 ddt_t *ddt = ddt_select(zio->io_spa, bp); 1920 ddt_entry_t *dde = ddt_repair_start(ddt, bp); 1921 ddt_phys_t *ddp = dde->dde_phys; 1922 ddt_phys_t *ddp_self = ddt_phys_select(dde, bp); 1923 blkptr_t blk; 1924 1925 ASSERT(zio->io_vsd == NULL); 1926 zio->io_vsd = dde; 1927 1928 if (ddp_self == NULL) 1929 return (ZIO_PIPELINE_CONTINUE); 1930 1931 for (int p = 0; p < DDT_PHYS_TYPES; p++, ddp++) { 1932 if (ddp->ddp_phys_birth == 0 || ddp == ddp_self) 1933 continue; 1934 ddt_bp_create(ddt->ddt_checksum, &dde->dde_key, ddp, 1935 &blk); 1936 zio_nowait(zio_read(zio, zio->io_spa, &blk, 1937 zio_buf_alloc(zio->io_size), zio->io_size, 1938 zio_ddt_child_read_done, dde, zio->io_priority, 1939 ZIO_DDT_CHILD_FLAGS(zio) | ZIO_FLAG_DONT_PROPAGATE, 1940 &zio->io_bookmark)); 1941 } 1942 return (ZIO_PIPELINE_CONTINUE); 1943 } 1944 1945 zio_nowait(zio_read(zio, zio->io_spa, bp, 1946 zio->io_data, zio->io_size, NULL, NULL, zio->io_priority, 1947 ZIO_DDT_CHILD_FLAGS(zio), &zio->io_bookmark)); 1948 1949 return (ZIO_PIPELINE_CONTINUE); 1950 } 1951 1952 static int 1953 zio_ddt_read_done(zio_t *zio) 1954 { 1955 blkptr_t *bp = zio->io_bp; 1956 1957 if (zio_wait_for_children(zio, ZIO_CHILD_DDT, ZIO_WAIT_DONE)) 1958 return (ZIO_PIPELINE_STOP); 1959 1960 ASSERT(BP_GET_DEDUP(bp)); 1961 ASSERT(BP_GET_PSIZE(bp) == zio->io_size); 1962 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL); 1963 1964 if (zio->io_child_error[ZIO_CHILD_DDT]) { 1965 ddt_t *ddt = ddt_select(zio->io_spa, bp); 1966 ddt_entry_t *dde = zio->io_vsd; 1967 if (ddt == NULL) { 1968 ASSERT(spa_load_state(zio->io_spa) != SPA_LOAD_NONE); 1969 return (ZIO_PIPELINE_CONTINUE); 1970 } 1971 if (dde == NULL) { 1972 zio->io_stage = ZIO_STAGE_DDT_READ_START >> 1; 1973 zio_taskq_dispatch(zio, ZIO_TASKQ_ISSUE, B_FALSE); 1974 return (ZIO_PIPELINE_STOP); 1975 } 1976 if (dde->dde_repair_data != NULL) { 1977 bcopy(dde->dde_repair_data, zio->io_data, zio->io_size); 1978 zio->io_child_error[ZIO_CHILD_DDT] = 0; 1979 } 1980 ddt_repair_done(ddt, dde); 1981 zio->io_vsd = NULL; 1982 } 1983 1984 ASSERT(zio->io_vsd == NULL); 1985 1986 return (ZIO_PIPELINE_CONTINUE); 1987 } 1988 1989 static boolean_t 1990 zio_ddt_collision(zio_t *zio, ddt_t *ddt, ddt_entry_t *dde) 1991 { 1992 spa_t *spa = zio->io_spa; 1993 1994 /* 1995 * Note: we compare the original data, not the transformed data, 1996 * because when zio->io_bp is an override bp, we will not have 1997 * pushed the I/O transforms. That's an important optimization 1998 * because otherwise we'd compress/encrypt all dmu_sync() data twice. 1999 */ 2000 for (int p = DDT_PHYS_SINGLE; p <= DDT_PHYS_TRIPLE; p++) { 2001 zio_t *lio = dde->dde_lead_zio[p]; 2002 2003 if (lio != NULL) { 2004 return (lio->io_orig_size != zio->io_orig_size || 2005 bcmp(zio->io_orig_data, lio->io_orig_data, 2006 zio->io_orig_size) != 0); 2007 } 2008 } 2009 2010 for (int p = DDT_PHYS_SINGLE; p <= DDT_PHYS_TRIPLE; p++) { 2011 ddt_phys_t *ddp = &dde->dde_phys[p]; 2012 2013 if (ddp->ddp_phys_birth != 0) { 2014 arc_buf_t *abuf = NULL; 2015 uint32_t aflags = ARC_WAIT; 2016 blkptr_t blk = *zio->io_bp; 2017 int error; 2018 2019 ddt_bp_fill(ddp, &blk, ddp->ddp_phys_birth); 2020 2021 ddt_exit(ddt); 2022 2023 error = arc_read(NULL, spa, &blk, 2024 arc_getbuf_func, &abuf, ZIO_PRIORITY_SYNC_READ, 2025 ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE, 2026 &aflags, &zio->io_bookmark); 2027 2028 if (error == 0) { 2029 if (arc_buf_size(abuf) != zio->io_orig_size || 2030 bcmp(abuf->b_data, zio->io_orig_data, 2031 zio->io_orig_size) != 0) 2032 error = SET_ERROR(EEXIST); 2033 VERIFY(arc_buf_remove_ref(abuf, &abuf)); 2034 } 2035 2036 ddt_enter(ddt); 2037 return (error != 0); 2038 } 2039 } 2040 2041 return (B_FALSE); 2042 } 2043 2044 static void 2045 zio_ddt_child_write_ready(zio_t *zio) 2046 { 2047 int p = zio->io_prop.zp_copies; 2048 ddt_t *ddt = ddt_select(zio->io_spa, zio->io_bp); 2049 ddt_entry_t *dde = zio->io_private; 2050 ddt_phys_t *ddp = &dde->dde_phys[p]; 2051 zio_t *pio; 2052 2053 if (zio->io_error) 2054 return; 2055 2056 ddt_enter(ddt); 2057 2058 ASSERT(dde->dde_lead_zio[p] == zio); 2059 2060 ddt_phys_fill(ddp, zio->io_bp); 2061 2062 while ((pio = zio_walk_parents(zio)) != NULL) 2063 ddt_bp_fill(ddp, pio->io_bp, zio->io_txg); 2064 2065 ddt_exit(ddt); 2066 } 2067 2068 static void 2069 zio_ddt_child_write_done(zio_t *zio) 2070 { 2071 int p = zio->io_prop.zp_copies; 2072 ddt_t *ddt = ddt_select(zio->io_spa, zio->io_bp); 2073 ddt_entry_t *dde = zio->io_private; 2074 ddt_phys_t *ddp = &dde->dde_phys[p]; 2075 2076 ddt_enter(ddt); 2077 2078 ASSERT(ddp->ddp_refcnt == 0); 2079 ASSERT(dde->dde_lead_zio[p] == zio); 2080 dde->dde_lead_zio[p] = NULL; 2081 2082 if (zio->io_error == 0) { 2083 while (zio_walk_parents(zio) != NULL) 2084 ddt_phys_addref(ddp); 2085 } else { 2086 ddt_phys_clear(ddp); 2087 } 2088 2089 ddt_exit(ddt); 2090 } 2091 2092 static void 2093 zio_ddt_ditto_write_done(zio_t *zio) 2094 { 2095 int p = DDT_PHYS_DITTO; 2096 zio_prop_t *zp = &zio->io_prop; 2097 blkptr_t *bp = zio->io_bp; 2098 ddt_t *ddt = ddt_select(zio->io_spa, bp); 2099 ddt_entry_t *dde = zio->io_private; 2100 ddt_phys_t *ddp = &dde->dde_phys[p]; 2101 ddt_key_t *ddk = &dde->dde_key; 2102 2103 ddt_enter(ddt); 2104 2105 ASSERT(ddp->ddp_refcnt == 0); 2106 ASSERT(dde->dde_lead_zio[p] == zio); 2107 dde->dde_lead_zio[p] = NULL; 2108 2109 if (zio->io_error == 0) { 2110 ASSERT(ZIO_CHECKSUM_EQUAL(bp->blk_cksum, ddk->ddk_cksum)); 2111 ASSERT(zp->zp_copies < SPA_DVAS_PER_BP); 2112 ASSERT(zp->zp_copies == BP_GET_NDVAS(bp) - BP_IS_GANG(bp)); 2113 if (ddp->ddp_phys_birth != 0) 2114 ddt_phys_free(ddt, ddk, ddp, zio->io_txg); 2115 ddt_phys_fill(ddp, bp); 2116 } 2117 2118 ddt_exit(ddt); 2119 } 2120 2121 static int 2122 zio_ddt_write(zio_t *zio) 2123 { 2124 spa_t *spa = zio->io_spa; 2125 blkptr_t *bp = zio->io_bp; 2126 uint64_t txg = zio->io_txg; 2127 zio_prop_t *zp = &zio->io_prop; 2128 int p = zp->zp_copies; 2129 int ditto_copies; 2130 zio_t *cio = NULL; 2131 zio_t *dio = NULL; 2132 ddt_t *ddt = ddt_select(spa, bp); 2133 ddt_entry_t *dde; 2134 ddt_phys_t *ddp; 2135 2136 ASSERT(BP_GET_DEDUP(bp)); 2137 ASSERT(BP_GET_CHECKSUM(bp) == zp->zp_checksum); 2138 ASSERT(BP_IS_HOLE(bp) || zio->io_bp_override); 2139 2140 ddt_enter(ddt); 2141 dde = ddt_lookup(ddt, bp, B_TRUE); 2142 ddp = &dde->dde_phys[p]; 2143 2144 if (zp->zp_dedup_verify && zio_ddt_collision(zio, ddt, dde)) { 2145 /* 2146 * If we're using a weak checksum, upgrade to a strong checksum 2147 * and try again. If we're already using a strong checksum, 2148 * we can't resolve it, so just convert to an ordinary write. 2149 * (And automatically e-mail a paper to Nature?) 2150 */ 2151 if (!zio_checksum_table[zp->zp_checksum].ci_dedup) { 2152 zp->zp_checksum = spa_dedup_checksum(spa); 2153 zio_pop_transforms(zio); 2154 zio->io_stage = ZIO_STAGE_OPEN; 2155 BP_ZERO(bp); 2156 } else { 2157 zp->zp_dedup = B_FALSE; 2158 } 2159 zio->io_pipeline = ZIO_WRITE_PIPELINE; 2160 ddt_exit(ddt); 2161 return (ZIO_PIPELINE_CONTINUE); 2162 } 2163 2164 ditto_copies = ddt_ditto_copies_needed(ddt, dde, ddp); 2165 ASSERT(ditto_copies < SPA_DVAS_PER_BP); 2166 2167 if (ditto_copies > ddt_ditto_copies_present(dde) && 2168 dde->dde_lead_zio[DDT_PHYS_DITTO] == NULL) { 2169 zio_prop_t czp = *zp; 2170 2171 czp.zp_copies = ditto_copies; 2172 2173 /* 2174 * If we arrived here with an override bp, we won't have run 2175 * the transform stack, so we won't have the data we need to 2176 * generate a child i/o. So, toss the override bp and restart. 2177 * This is safe, because using the override bp is just an 2178 * optimization; and it's rare, so the cost doesn't matter. 2179 */ 2180 if (zio->io_bp_override) { 2181 zio_pop_transforms(zio); 2182 zio->io_stage = ZIO_STAGE_OPEN; 2183 zio->io_pipeline = ZIO_WRITE_PIPELINE; 2184 zio->io_bp_override = NULL; 2185 BP_ZERO(bp); 2186 ddt_exit(ddt); 2187 return (ZIO_PIPELINE_CONTINUE); 2188 } 2189 2190 dio = zio_write(zio, spa, txg, bp, zio->io_orig_data, 2191 zio->io_orig_size, &czp, NULL, NULL, 2192 zio_ddt_ditto_write_done, dde, zio->io_priority, 2193 ZIO_DDT_CHILD_FLAGS(zio), &zio->io_bookmark); 2194 2195 zio_push_transform(dio, zio->io_data, zio->io_size, 0, NULL); 2196 dde->dde_lead_zio[DDT_PHYS_DITTO] = dio; 2197 } 2198 2199 if (ddp->ddp_phys_birth != 0 || dde->dde_lead_zio[p] != NULL) { 2200 if (ddp->ddp_phys_birth != 0) 2201 ddt_bp_fill(ddp, bp, txg); 2202 if (dde->dde_lead_zio[p] != NULL) 2203 zio_add_child(zio, dde->dde_lead_zio[p]); 2204 else 2205 ddt_phys_addref(ddp); 2206 } else if (zio->io_bp_override) { 2207 ASSERT(bp->blk_birth == txg); 2208 ASSERT(BP_EQUAL(bp, zio->io_bp_override)); 2209 ddt_phys_fill(ddp, bp); 2210 ddt_phys_addref(ddp); 2211 } else { 2212 cio = zio_write(zio, spa, txg, bp, zio->io_orig_data, 2213 zio->io_orig_size, zp, zio_ddt_child_write_ready, NULL, 2214 zio_ddt_child_write_done, dde, zio->io_priority, 2215 ZIO_DDT_CHILD_FLAGS(zio), &zio->io_bookmark); 2216 2217 zio_push_transform(cio, zio->io_data, zio->io_size, 0, NULL); 2218 dde->dde_lead_zio[p] = cio; 2219 } 2220 2221 ddt_exit(ddt); 2222 2223 if (cio) 2224 zio_nowait(cio); 2225 if (dio) 2226 zio_nowait(dio); 2227 2228 return (ZIO_PIPELINE_CONTINUE); 2229 } 2230 2231 ddt_entry_t *freedde; /* for debugging */ 2232 2233 static int 2234 zio_ddt_free(zio_t *zio) 2235 { 2236 spa_t *spa = zio->io_spa; 2237 blkptr_t *bp = zio->io_bp; 2238 ddt_t *ddt = ddt_select(spa, bp); 2239 ddt_entry_t *dde; 2240 ddt_phys_t *ddp; 2241 2242 ASSERT(BP_GET_DEDUP(bp)); 2243 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL); 2244 2245 ddt_enter(ddt); 2246 freedde = dde = ddt_lookup(ddt, bp, B_TRUE); 2247 ddp = ddt_phys_select(dde, bp); 2248 ddt_phys_decref(ddp); 2249 ddt_exit(ddt); 2250 2251 return (ZIO_PIPELINE_CONTINUE); 2252 } 2253 2254 /* 2255 * ========================================================================== 2256 * Allocate and free blocks 2257 * ========================================================================== 2258 */ 2259 static int 2260 zio_dva_allocate(zio_t *zio) 2261 { 2262 spa_t *spa = zio->io_spa; 2263 metaslab_class_t *mc = spa_normal_class(spa); 2264 blkptr_t *bp = zio->io_bp; 2265 int error; 2266 int flags = 0; 2267 2268 if (zio->io_gang_leader == NULL) { 2269 ASSERT(zio->io_child_type > ZIO_CHILD_GANG); 2270 zio->io_gang_leader = zio; 2271 } 2272 2273 ASSERT(BP_IS_HOLE(bp)); 2274 ASSERT0(BP_GET_NDVAS(bp)); 2275 ASSERT3U(zio->io_prop.zp_copies, >, 0); 2276 ASSERT3U(zio->io_prop.zp_copies, <=, spa_max_replication(spa)); 2277 ASSERT3U(zio->io_size, ==, BP_GET_PSIZE(bp)); 2278 2279 /* 2280 * The dump device does not support gang blocks so allocation on 2281 * behalf of the dump device (i.e. ZIO_FLAG_NODATA) must avoid 2282 * the "fast" gang feature. 2283 */ 2284 flags |= (zio->io_flags & ZIO_FLAG_NODATA) ? METASLAB_GANG_AVOID : 0; 2285 flags |= (zio->io_flags & ZIO_FLAG_GANG_CHILD) ? 2286 METASLAB_GANG_CHILD : 0; 2287 error = metaslab_alloc(spa, mc, zio->io_size, bp, 2288 zio->io_prop.zp_copies, zio->io_txg, NULL, flags); 2289 2290 if (error) { 2291 spa_dbgmsg(spa, "%s: metaslab allocation failure: zio %p, " 2292 "size %llu, error %d", spa_name(spa), zio, zio->io_size, 2293 error); 2294 if (error == ENOSPC && zio->io_size > SPA_MINBLOCKSIZE) 2295 return (zio_write_gang_block(zio)); 2296 zio->io_error = error; 2297 } 2298 2299 return (ZIO_PIPELINE_CONTINUE); 2300 } 2301 2302 static int 2303 zio_dva_free(zio_t *zio) 2304 { 2305 metaslab_free(zio->io_spa, zio->io_bp, zio->io_txg, B_FALSE); 2306 2307 return (ZIO_PIPELINE_CONTINUE); 2308 } 2309 2310 static int 2311 zio_dva_claim(zio_t *zio) 2312 { 2313 int error; 2314 2315 error = metaslab_claim(zio->io_spa, zio->io_bp, zio->io_txg); 2316 if (error) 2317 zio->io_error = error; 2318 2319 return (ZIO_PIPELINE_CONTINUE); 2320 } 2321 2322 /* 2323 * Undo an allocation. This is used by zio_done() when an I/O fails 2324 * and we want to give back the block we just allocated. 2325 * This handles both normal blocks and gang blocks. 2326 */ 2327 static void 2328 zio_dva_unallocate(zio_t *zio, zio_gang_node_t *gn, blkptr_t *bp) 2329 { 2330 ASSERT(bp->blk_birth == zio->io_txg || BP_IS_HOLE(bp)); 2331 ASSERT(zio->io_bp_override == NULL); 2332 2333 if (!BP_IS_HOLE(bp)) 2334 metaslab_free(zio->io_spa, bp, bp->blk_birth, B_TRUE); 2335 2336 if (gn != NULL) { 2337 for (int g = 0; g < SPA_GBH_NBLKPTRS; g++) { 2338 zio_dva_unallocate(zio, gn->gn_child[g], 2339 &gn->gn_gbh->zg_blkptr[g]); 2340 } 2341 } 2342 } 2343 2344 /* 2345 * Try to allocate an intent log block. Return 0 on success, errno on failure. 2346 */ 2347 int 2348 zio_alloc_zil(spa_t *spa, uint64_t txg, blkptr_t *new_bp, blkptr_t *old_bp, 2349 uint64_t size, boolean_t use_slog) 2350 { 2351 int error = 1; 2352 2353 ASSERT(txg > spa_syncing_txg(spa)); 2354 2355 /* 2356 * ZIL blocks are always contiguous (i.e. not gang blocks) so we 2357 * set the METASLAB_GANG_AVOID flag so that they don't "fast gang" 2358 * when allocating them. 2359 */ 2360 if (use_slog) { 2361 error = metaslab_alloc(spa, spa_log_class(spa), size, 2362 new_bp, 1, txg, old_bp, 2363 METASLAB_HINTBP_AVOID | METASLAB_GANG_AVOID); 2364 } 2365 2366 if (error) { 2367 error = metaslab_alloc(spa, spa_normal_class(spa), size, 2368 new_bp, 1, txg, old_bp, 2369 METASLAB_HINTBP_AVOID); 2370 } 2371 2372 if (error == 0) { 2373 BP_SET_LSIZE(new_bp, size); 2374 BP_SET_PSIZE(new_bp, size); 2375 BP_SET_COMPRESS(new_bp, ZIO_COMPRESS_OFF); 2376 BP_SET_CHECKSUM(new_bp, 2377 spa_version(spa) >= SPA_VERSION_SLIM_ZIL 2378 ? ZIO_CHECKSUM_ZILOG2 : ZIO_CHECKSUM_ZILOG); 2379 BP_SET_TYPE(new_bp, DMU_OT_INTENT_LOG); 2380 BP_SET_LEVEL(new_bp, 0); 2381 BP_SET_DEDUP(new_bp, 0); 2382 BP_SET_BYTEORDER(new_bp, ZFS_HOST_BYTEORDER); 2383 } 2384 2385 return (error); 2386 } 2387 2388 /* 2389 * Free an intent log block. 2390 */ 2391 void 2392 zio_free_zil(spa_t *spa, uint64_t txg, blkptr_t *bp) 2393 { 2394 ASSERT(BP_GET_TYPE(bp) == DMU_OT_INTENT_LOG); 2395 ASSERT(!BP_IS_GANG(bp)); 2396 2397 zio_free(spa, txg, bp); 2398 } 2399 2400 /* 2401 * ========================================================================== 2402 * Read and write to physical devices 2403 * ========================================================================== 2404 */ 2405 static int 2406 zio_vdev_io_start(zio_t *zio) 2407 { 2408 vdev_t *vd = zio->io_vd; 2409 uint64_t align; 2410 spa_t *spa = zio->io_spa; 2411 2412 ASSERT(zio->io_error == 0); 2413 ASSERT(zio->io_child_error[ZIO_CHILD_VDEV] == 0); 2414 2415 if (vd == NULL) { 2416 if (!(zio->io_flags & ZIO_FLAG_CONFIG_WRITER)) 2417 spa_config_enter(spa, SCL_ZIO, zio, RW_READER); 2418 2419 /* 2420 * The mirror_ops handle multiple DVAs in a single BP. 2421 */ 2422 return (vdev_mirror_ops.vdev_op_io_start(zio)); 2423 } 2424 2425 /* 2426 * We keep track of time-sensitive I/Os so that the scan thread 2427 * can quickly react to certain workloads. In particular, we care 2428 * about non-scrubbing, top-level reads and writes with the following 2429 * characteristics: 2430 * - synchronous writes of user data to non-slog devices 2431 * - any reads of user data 2432 * When these conditions are met, adjust the timestamp of spa_last_io 2433 * which allows the scan thread to adjust its workload accordingly. 2434 */ 2435 if (!(zio->io_flags & ZIO_FLAG_SCAN_THREAD) && zio->io_bp != NULL && 2436 vd == vd->vdev_top && !vd->vdev_islog && 2437 zio->io_bookmark.zb_objset != DMU_META_OBJSET && 2438 zio->io_txg != spa_syncing_txg(spa)) { 2439 uint64_t old = spa->spa_last_io; 2440 uint64_t new = ddi_get_lbolt64(); 2441 if (old != new) 2442 (void) atomic_cas_64(&spa->spa_last_io, old, new); 2443 } 2444 2445 align = 1ULL << vd->vdev_top->vdev_ashift; 2446 2447 if (P2PHASE(zio->io_size, align) != 0) { 2448 uint64_t asize = P2ROUNDUP(zio->io_size, align); 2449 char *abuf = zio_buf_alloc(asize); 2450 ASSERT(vd == vd->vdev_top); 2451 if (zio->io_type == ZIO_TYPE_WRITE) { 2452 bcopy(zio->io_data, abuf, zio->io_size); 2453 bzero(abuf + zio->io_size, asize - zio->io_size); 2454 } 2455 zio_push_transform(zio, abuf, asize, asize, zio_subblock); 2456 } 2457 2458 ASSERT(P2PHASE(zio->io_offset, align) == 0); 2459 ASSERT(P2PHASE(zio->io_size, align) == 0); 2460 VERIFY(zio->io_type != ZIO_TYPE_WRITE || spa_writeable(spa)); 2461 2462 /* 2463 * If this is a repair I/O, and there's no self-healing involved -- 2464 * that is, we're just resilvering what we expect to resilver -- 2465 * then don't do the I/O unless zio's txg is actually in vd's DTL. 2466 * This prevents spurious resilvering with nested replication. 2467 * For example, given a mirror of mirrors, (A+B)+(C+D), if only 2468 * A is out of date, we'll read from C+D, then use the data to 2469 * resilver A+B -- but we don't actually want to resilver B, just A. 2470 * The top-level mirror has no way to know this, so instead we just 2471 * discard unnecessary repairs as we work our way down the vdev tree. 2472 * The same logic applies to any form of nested replication: 2473 * ditto + mirror, RAID-Z + replacing, etc. This covers them all. 2474 */ 2475 if ((zio->io_flags & ZIO_FLAG_IO_REPAIR) && 2476 !(zio->io_flags & ZIO_FLAG_SELF_HEAL) && 2477 zio->io_txg != 0 && /* not a delegated i/o */ 2478 !vdev_dtl_contains(vd, DTL_PARTIAL, zio->io_txg, 1)) { 2479 ASSERT(zio->io_type == ZIO_TYPE_WRITE); 2480 zio_vdev_io_bypass(zio); 2481 return (ZIO_PIPELINE_CONTINUE); 2482 } 2483 2484 if (vd->vdev_ops->vdev_op_leaf && 2485 (zio->io_type == ZIO_TYPE_READ || zio->io_type == ZIO_TYPE_WRITE)) { 2486 2487 if (zio->io_type == ZIO_TYPE_READ && vdev_cache_read(zio) == 0) 2488 return (ZIO_PIPELINE_CONTINUE); 2489 2490 if ((zio = vdev_queue_io(zio)) == NULL) 2491 return (ZIO_PIPELINE_STOP); 2492 2493 if (!vdev_accessible(vd, zio)) { 2494 zio->io_error = SET_ERROR(ENXIO); 2495 zio_interrupt(zio); 2496 return (ZIO_PIPELINE_STOP); 2497 } 2498 } 2499 2500 return (vd->vdev_ops->vdev_op_io_start(zio)); 2501 } 2502 2503 static int 2504 zio_vdev_io_done(zio_t *zio) 2505 { 2506 vdev_t *vd = zio->io_vd; 2507 vdev_ops_t *ops = vd ? vd->vdev_ops : &vdev_mirror_ops; 2508 boolean_t unexpected_error = B_FALSE; 2509 2510 if (zio_wait_for_children(zio, ZIO_CHILD_VDEV, ZIO_WAIT_DONE)) 2511 return (ZIO_PIPELINE_STOP); 2512 2513 ASSERT(zio->io_type == ZIO_TYPE_READ || zio->io_type == ZIO_TYPE_WRITE); 2514 2515 if (vd != NULL && vd->vdev_ops->vdev_op_leaf) { 2516 2517 vdev_queue_io_done(zio); 2518 2519 if (zio->io_type == ZIO_TYPE_WRITE) 2520 vdev_cache_write(zio); 2521 2522 if (zio_injection_enabled && zio->io_error == 0) 2523 zio->io_error = zio_handle_device_injection(vd, 2524 zio, EIO); 2525 2526 if (zio_injection_enabled && zio->io_error == 0) 2527 zio->io_error = zio_handle_label_injection(zio, EIO); 2528 2529 if (zio->io_error) { 2530 if (!vdev_accessible(vd, zio)) { 2531 zio->io_error = SET_ERROR(ENXIO); 2532 } else { 2533 unexpected_error = B_TRUE; 2534 } 2535 } 2536 } 2537 2538 ops->vdev_op_io_done(zio); 2539 2540 if (unexpected_error) 2541 VERIFY(vdev_probe(vd, zio) == NULL); 2542 2543 return (ZIO_PIPELINE_CONTINUE); 2544 } 2545 2546 /* 2547 * For non-raidz ZIOs, we can just copy aside the bad data read from the 2548 * disk, and use that to finish the checksum ereport later. 2549 */ 2550 static void 2551 zio_vsd_default_cksum_finish(zio_cksum_report_t *zcr, 2552 const void *good_buf) 2553 { 2554 /* no processing needed */ 2555 zfs_ereport_finish_checksum(zcr, good_buf, zcr->zcr_cbdata, B_FALSE); 2556 } 2557 2558 /*ARGSUSED*/ 2559 void 2560 zio_vsd_default_cksum_report(zio_t *zio, zio_cksum_report_t *zcr, void *ignored) 2561 { 2562 void *buf = zio_buf_alloc(zio->io_size); 2563 2564 bcopy(zio->io_data, buf, zio->io_size); 2565 2566 zcr->zcr_cbinfo = zio->io_size; 2567 zcr->zcr_cbdata = buf; 2568 zcr->zcr_finish = zio_vsd_default_cksum_finish; 2569 zcr->zcr_free = zio_buf_free; 2570 } 2571 2572 static int 2573 zio_vdev_io_assess(zio_t *zio) 2574 { 2575 vdev_t *vd = zio->io_vd; 2576 2577 if (zio_wait_for_children(zio, ZIO_CHILD_VDEV, ZIO_WAIT_DONE)) 2578 return (ZIO_PIPELINE_STOP); 2579 2580 if (vd == NULL && !(zio->io_flags & ZIO_FLAG_CONFIG_WRITER)) 2581 spa_config_exit(zio->io_spa, SCL_ZIO, zio); 2582 2583 if (zio->io_vsd != NULL) { 2584 zio->io_vsd_ops->vsd_free(zio); 2585 zio->io_vsd = NULL; 2586 } 2587 2588 if (zio_injection_enabled && zio->io_error == 0) 2589 zio->io_error = zio_handle_fault_injection(zio, EIO); 2590 2591 /* 2592 * If the I/O failed, determine whether we should attempt to retry it. 2593 * 2594 * On retry, we cut in line in the issue queue, since we don't want 2595 * compression/checksumming/etc. work to prevent our (cheap) IO reissue. 2596 */ 2597 if (zio->io_error && vd == NULL && 2598 !(zio->io_flags & (ZIO_FLAG_DONT_RETRY | ZIO_FLAG_IO_RETRY))) { 2599 ASSERT(!(zio->io_flags & ZIO_FLAG_DONT_QUEUE)); /* not a leaf */ 2600 ASSERT(!(zio->io_flags & ZIO_FLAG_IO_BYPASS)); /* not a leaf */ 2601 zio->io_error = 0; 2602 zio->io_flags |= ZIO_FLAG_IO_RETRY | 2603 ZIO_FLAG_DONT_CACHE | ZIO_FLAG_DONT_AGGREGATE; 2604 zio->io_stage = ZIO_STAGE_VDEV_IO_START >> 1; 2605 zio_taskq_dispatch(zio, ZIO_TASKQ_ISSUE, 2606 zio_requeue_io_start_cut_in_line); 2607 return (ZIO_PIPELINE_STOP); 2608 } 2609 2610 /* 2611 * If we got an error on a leaf device, convert it to ENXIO 2612 * if the device is not accessible at all. 2613 */ 2614 if (zio->io_error && vd != NULL && vd->vdev_ops->vdev_op_leaf && 2615 !vdev_accessible(vd, zio)) 2616 zio->io_error = SET_ERROR(ENXIO); 2617 2618 /* 2619 * If we can't write to an interior vdev (mirror or RAID-Z), 2620 * set vdev_cant_write so that we stop trying to allocate from it. 2621 */ 2622 if (zio->io_error == ENXIO && zio->io_type == ZIO_TYPE_WRITE && 2623 vd != NULL && !vd->vdev_ops->vdev_op_leaf) { 2624 vd->vdev_cant_write = B_TRUE; 2625 } 2626 2627 if (zio->io_error) 2628 zio->io_pipeline = ZIO_INTERLOCK_PIPELINE; 2629 2630 if (vd != NULL && vd->vdev_ops->vdev_op_leaf && 2631 zio->io_physdone != NULL) { 2632 ASSERT(!(zio->io_flags & ZIO_FLAG_DELEGATED)); 2633 ASSERT(zio->io_child_type == ZIO_CHILD_VDEV); 2634 zio->io_physdone(zio->io_logical); 2635 } 2636 2637 return (ZIO_PIPELINE_CONTINUE); 2638 } 2639 2640 void 2641 zio_vdev_io_reissue(zio_t *zio) 2642 { 2643 ASSERT(zio->io_stage == ZIO_STAGE_VDEV_IO_START); 2644 ASSERT(zio->io_error == 0); 2645 2646 zio->io_stage >>= 1; 2647 } 2648 2649 void 2650 zio_vdev_io_redone(zio_t *zio) 2651 { 2652 ASSERT(zio->io_stage == ZIO_STAGE_VDEV_IO_DONE); 2653 2654 zio->io_stage >>= 1; 2655 } 2656 2657 void 2658 zio_vdev_io_bypass(zio_t *zio) 2659 { 2660 ASSERT(zio->io_stage == ZIO_STAGE_VDEV_IO_START); 2661 ASSERT(zio->io_error == 0); 2662 2663 zio->io_flags |= ZIO_FLAG_IO_BYPASS; 2664 zio->io_stage = ZIO_STAGE_VDEV_IO_ASSESS >> 1; 2665 } 2666 2667 /* 2668 * ========================================================================== 2669 * Generate and verify checksums 2670 * ========================================================================== 2671 */ 2672 static int 2673 zio_checksum_generate(zio_t *zio) 2674 { 2675 blkptr_t *bp = zio->io_bp; 2676 enum zio_checksum checksum; 2677 2678 if (bp == NULL) { 2679 /* 2680 * This is zio_write_phys(). 2681 * We're either generating a label checksum, or none at all. 2682 */ 2683 checksum = zio->io_prop.zp_checksum; 2684 2685 if (checksum == ZIO_CHECKSUM_OFF) 2686 return (ZIO_PIPELINE_CONTINUE); 2687 2688 ASSERT(checksum == ZIO_CHECKSUM_LABEL); 2689 } else { 2690 if (BP_IS_GANG(bp) && zio->io_child_type == ZIO_CHILD_GANG) { 2691 ASSERT(!IO_IS_ALLOCATING(zio)); 2692 checksum = ZIO_CHECKSUM_GANG_HEADER; 2693 } else { 2694 checksum = BP_GET_CHECKSUM(bp); 2695 } 2696 } 2697 2698 zio_checksum_compute(zio, checksum, zio->io_data, zio->io_size); 2699 2700 return (ZIO_PIPELINE_CONTINUE); 2701 } 2702 2703 static int 2704 zio_checksum_verify(zio_t *zio) 2705 { 2706 zio_bad_cksum_t info; 2707 blkptr_t *bp = zio->io_bp; 2708 int error; 2709 2710 ASSERT(zio->io_vd != NULL); 2711 2712 if (bp == NULL) { 2713 /* 2714 * This is zio_read_phys(). 2715 * We're either verifying a label checksum, or nothing at all. 2716 */ 2717 if (zio->io_prop.zp_checksum == ZIO_CHECKSUM_OFF) 2718 return (ZIO_PIPELINE_CONTINUE); 2719 2720 ASSERT(zio->io_prop.zp_checksum == ZIO_CHECKSUM_LABEL); 2721 } 2722 2723 if ((error = zio_checksum_error(zio, &info)) != 0) { 2724 zio->io_error = error; 2725 if (!(zio->io_flags & ZIO_FLAG_SPECULATIVE)) { 2726 zfs_ereport_start_checksum(zio->io_spa, 2727 zio->io_vd, zio, zio->io_offset, 2728 zio->io_size, NULL, &info); 2729 } 2730 } 2731 2732 return (ZIO_PIPELINE_CONTINUE); 2733 } 2734 2735 /* 2736 * Called by RAID-Z to ensure we don't compute the checksum twice. 2737 */ 2738 void 2739 zio_checksum_verified(zio_t *zio) 2740 { 2741 zio->io_pipeline &= ~ZIO_STAGE_CHECKSUM_VERIFY; 2742 } 2743 2744 /* 2745 * ========================================================================== 2746 * Error rank. Error are ranked in the order 0, ENXIO, ECKSUM, EIO, other. 2747 * An error of 0 indictes success. ENXIO indicates whole-device failure, 2748 * which may be transient (e.g. unplugged) or permament. ECKSUM and EIO 2749 * indicate errors that are specific to one I/O, and most likely permanent. 2750 * Any other error is presumed to be worse because we weren't expecting it. 2751 * ========================================================================== 2752 */ 2753 int 2754 zio_worst_error(int e1, int e2) 2755 { 2756 static int zio_error_rank[] = { 0, ENXIO, ECKSUM, EIO }; 2757 int r1, r2; 2758 2759 for (r1 = 0; r1 < sizeof (zio_error_rank) / sizeof (int); r1++) 2760 if (e1 == zio_error_rank[r1]) 2761 break; 2762 2763 for (r2 = 0; r2 < sizeof (zio_error_rank) / sizeof (int); r2++) 2764 if (e2 == zio_error_rank[r2]) 2765 break; 2766 2767 return (r1 > r2 ? e1 : e2); 2768 } 2769 2770 /* 2771 * ========================================================================== 2772 * I/O completion 2773 * ========================================================================== 2774 */ 2775 static int 2776 zio_ready(zio_t *zio) 2777 { 2778 blkptr_t *bp = zio->io_bp; 2779 zio_t *pio, *pio_next; 2780 2781 if (zio_wait_for_children(zio, ZIO_CHILD_GANG, ZIO_WAIT_READY) || 2782 zio_wait_for_children(zio, ZIO_CHILD_DDT, ZIO_WAIT_READY)) 2783 return (ZIO_PIPELINE_STOP); 2784 2785 if (zio->io_ready) { 2786 ASSERT(IO_IS_ALLOCATING(zio)); 2787 ASSERT(bp->blk_birth == zio->io_txg || BP_IS_HOLE(bp) || 2788 (zio->io_flags & ZIO_FLAG_NOPWRITE)); 2789 ASSERT(zio->io_children[ZIO_CHILD_GANG][ZIO_WAIT_READY] == 0); 2790 2791 zio->io_ready(zio); 2792 } 2793 2794 if (bp != NULL && bp != &zio->io_bp_copy) 2795 zio->io_bp_copy = *bp; 2796 2797 if (zio->io_error) 2798 zio->io_pipeline = ZIO_INTERLOCK_PIPELINE; 2799 2800 mutex_enter(&zio->io_lock); 2801 zio->io_state[ZIO_WAIT_READY] = 1; 2802 pio = zio_walk_parents(zio); 2803 mutex_exit(&zio->io_lock); 2804 2805 /* 2806 * As we notify zio's parents, new parents could be added. 2807 * New parents go to the head of zio's io_parent_list, however, 2808 * so we will (correctly) not notify them. The remainder of zio's 2809 * io_parent_list, from 'pio_next' onward, cannot change because 2810 * all parents must wait for us to be done before they can be done. 2811 */ 2812 for (; pio != NULL; pio = pio_next) { 2813 pio_next = zio_walk_parents(zio); 2814 zio_notify_parent(pio, zio, ZIO_WAIT_READY); 2815 } 2816 2817 if (zio->io_flags & ZIO_FLAG_NODATA) { 2818 if (BP_IS_GANG(bp)) { 2819 zio->io_flags &= ~ZIO_FLAG_NODATA; 2820 } else { 2821 ASSERT((uintptr_t)zio->io_data < SPA_MAXBLOCKSIZE); 2822 zio->io_pipeline &= ~ZIO_VDEV_IO_STAGES; 2823 } 2824 } 2825 2826 if (zio_injection_enabled && 2827 zio->io_spa->spa_syncing_txg == zio->io_txg) 2828 zio_handle_ignored_writes(zio); 2829 2830 return (ZIO_PIPELINE_CONTINUE); 2831 } 2832 2833 static int 2834 zio_done(zio_t *zio) 2835 { 2836 spa_t *spa = zio->io_spa; 2837 zio_t *lio = zio->io_logical; 2838 blkptr_t *bp = zio->io_bp; 2839 vdev_t *vd = zio->io_vd; 2840 uint64_t psize = zio->io_size; 2841 zio_t *pio, *pio_next; 2842 2843 /* 2844 * If our children haven't all completed, 2845 * wait for them and then repeat this pipeline stage. 2846 */ 2847 if (zio_wait_for_children(zio, ZIO_CHILD_VDEV, ZIO_WAIT_DONE) || 2848 zio_wait_for_children(zio, ZIO_CHILD_GANG, ZIO_WAIT_DONE) || 2849 zio_wait_for_children(zio, ZIO_CHILD_DDT, ZIO_WAIT_DONE) || 2850 zio_wait_for_children(zio, ZIO_CHILD_LOGICAL, ZIO_WAIT_DONE)) 2851 return (ZIO_PIPELINE_STOP); 2852 2853 for (int c = 0; c < ZIO_CHILD_TYPES; c++) 2854 for (int w = 0; w < ZIO_WAIT_TYPES; w++) 2855 ASSERT(zio->io_children[c][w] == 0); 2856 2857 if (bp != NULL) { 2858 ASSERT(bp->blk_pad[0] == 0); 2859 ASSERT(bp->blk_pad[1] == 0); 2860 ASSERT(bcmp(bp, &zio->io_bp_copy, sizeof (blkptr_t)) == 0 || 2861 (bp == zio_unique_parent(zio)->io_bp)); 2862 if (zio->io_type == ZIO_TYPE_WRITE && !BP_IS_HOLE(bp) && 2863 zio->io_bp_override == NULL && 2864 !(zio->io_flags & ZIO_FLAG_IO_REPAIR)) { 2865 ASSERT(!BP_SHOULD_BYTESWAP(bp)); 2866 ASSERT3U(zio->io_prop.zp_copies, <=, BP_GET_NDVAS(bp)); 2867 ASSERT(BP_COUNT_GANG(bp) == 0 || 2868 (BP_COUNT_GANG(bp) == BP_GET_NDVAS(bp))); 2869 } 2870 if (zio->io_flags & ZIO_FLAG_NOPWRITE) 2871 VERIFY(BP_EQUAL(bp, &zio->io_bp_orig)); 2872 } 2873 2874 /* 2875 * If there were child vdev/gang/ddt errors, they apply to us now. 2876 */ 2877 zio_inherit_child_errors(zio, ZIO_CHILD_VDEV); 2878 zio_inherit_child_errors(zio, ZIO_CHILD_GANG); 2879 zio_inherit_child_errors(zio, ZIO_CHILD_DDT); 2880 2881 /* 2882 * If the I/O on the transformed data was successful, generate any 2883 * checksum reports now while we still have the transformed data. 2884 */ 2885 if (zio->io_error == 0) { 2886 while (zio->io_cksum_report != NULL) { 2887 zio_cksum_report_t *zcr = zio->io_cksum_report; 2888 uint64_t align = zcr->zcr_align; 2889 uint64_t asize = P2ROUNDUP(psize, align); 2890 char *abuf = zio->io_data; 2891 2892 if (asize != psize) { 2893 abuf = zio_buf_alloc(asize); 2894 bcopy(zio->io_data, abuf, psize); 2895 bzero(abuf + psize, asize - psize); 2896 } 2897 2898 zio->io_cksum_report = zcr->zcr_next; 2899 zcr->zcr_next = NULL; 2900 zcr->zcr_finish(zcr, abuf); 2901 zfs_ereport_free_checksum(zcr); 2902 2903 if (asize != psize) 2904 zio_buf_free(abuf, asize); 2905 } 2906 } 2907 2908 zio_pop_transforms(zio); /* note: may set zio->io_error */ 2909 2910 vdev_stat_update(zio, psize); 2911 2912 if (zio->io_error) { 2913 /* 2914 * If this I/O is attached to a particular vdev, 2915 * generate an error message describing the I/O failure 2916 * at the block level. We ignore these errors if the 2917 * device is currently unavailable. 2918 */ 2919 if (zio->io_error != ECKSUM && vd != NULL && !vdev_is_dead(vd)) 2920 zfs_ereport_post(FM_EREPORT_ZFS_IO, spa, vd, zio, 0, 0); 2921 2922 if ((zio->io_error == EIO || !(zio->io_flags & 2923 (ZIO_FLAG_SPECULATIVE | ZIO_FLAG_DONT_PROPAGATE))) && 2924 zio == lio) { 2925 /* 2926 * For logical I/O requests, tell the SPA to log the 2927 * error and generate a logical data ereport. 2928 */ 2929 spa_log_error(spa, zio); 2930 zfs_ereport_post(FM_EREPORT_ZFS_DATA, spa, NULL, zio, 2931 0, 0); 2932 } 2933 } 2934 2935 if (zio->io_error && zio == lio) { 2936 /* 2937 * Determine whether zio should be reexecuted. This will 2938 * propagate all the way to the root via zio_notify_parent(). 2939 */ 2940 ASSERT(vd == NULL && bp != NULL); 2941 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL); 2942 2943 if (IO_IS_ALLOCATING(zio) && 2944 !(zio->io_flags & ZIO_FLAG_CANFAIL)) { 2945 if (zio->io_error != ENOSPC) 2946 zio->io_reexecute |= ZIO_REEXECUTE_NOW; 2947 else 2948 zio->io_reexecute |= ZIO_REEXECUTE_SUSPEND; 2949 } 2950 2951 if ((zio->io_type == ZIO_TYPE_READ || 2952 zio->io_type == ZIO_TYPE_FREE) && 2953 !(zio->io_flags & ZIO_FLAG_SCAN_THREAD) && 2954 zio->io_error == ENXIO && 2955 spa_load_state(spa) == SPA_LOAD_NONE && 2956 spa_get_failmode(spa) != ZIO_FAILURE_MODE_CONTINUE) 2957 zio->io_reexecute |= ZIO_REEXECUTE_SUSPEND; 2958 2959 if (!(zio->io_flags & ZIO_FLAG_CANFAIL) && !zio->io_reexecute) 2960 zio->io_reexecute |= ZIO_REEXECUTE_SUSPEND; 2961 2962 /* 2963 * Here is a possibly good place to attempt to do 2964 * either combinatorial reconstruction or error correction 2965 * based on checksums. It also might be a good place 2966 * to send out preliminary ereports before we suspend 2967 * processing. 2968 */ 2969 } 2970 2971 /* 2972 * If there were logical child errors, they apply to us now. 2973 * We defer this until now to avoid conflating logical child 2974 * errors with errors that happened to the zio itself when 2975 * updating vdev stats and reporting FMA events above. 2976 */ 2977 zio_inherit_child_errors(zio, ZIO_CHILD_LOGICAL); 2978 2979 if ((zio->io_error || zio->io_reexecute) && 2980 IO_IS_ALLOCATING(zio) && zio->io_gang_leader == zio && 2981 !(zio->io_flags & (ZIO_FLAG_IO_REWRITE | ZIO_FLAG_NOPWRITE))) 2982 zio_dva_unallocate(zio, zio->io_gang_tree, bp); 2983 2984 zio_gang_tree_free(&zio->io_gang_tree); 2985 2986 /* 2987 * Godfather I/Os should never suspend. 2988 */ 2989 if ((zio->io_flags & ZIO_FLAG_GODFATHER) && 2990 (zio->io_reexecute & ZIO_REEXECUTE_SUSPEND)) 2991 zio->io_reexecute = 0; 2992 2993 if (zio->io_reexecute) { 2994 /* 2995 * This is a logical I/O that wants to reexecute. 2996 * 2997 * Reexecute is top-down. When an i/o fails, if it's not 2998 * the root, it simply notifies its parent and sticks around. 2999 * The parent, seeing that it still has children in zio_done(), 3000 * does the same. This percolates all the way up to the root. 3001 * The root i/o will reexecute or suspend the entire tree. 3002 * 3003 * This approach ensures that zio_reexecute() honors 3004 * all the original i/o dependency relationships, e.g. 3005 * parents not executing until children are ready. 3006 */ 3007 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL); 3008 3009 zio->io_gang_leader = NULL; 3010 3011 mutex_enter(&zio->io_lock); 3012 zio->io_state[ZIO_WAIT_DONE] = 1; 3013 mutex_exit(&zio->io_lock); 3014 3015 /* 3016 * "The Godfather" I/O monitors its children but is 3017 * not a true parent to them. It will track them through 3018 * the pipeline but severs its ties whenever they get into 3019 * trouble (e.g. suspended). This allows "The Godfather" 3020 * I/O to return status without blocking. 3021 */ 3022 for (pio = zio_walk_parents(zio); pio != NULL; pio = pio_next) { 3023 zio_link_t *zl = zio->io_walk_link; 3024 pio_next = zio_walk_parents(zio); 3025 3026 if ((pio->io_flags & ZIO_FLAG_GODFATHER) && 3027 (zio->io_reexecute & ZIO_REEXECUTE_SUSPEND)) { 3028 zio_remove_child(pio, zio, zl); 3029 zio_notify_parent(pio, zio, ZIO_WAIT_DONE); 3030 } 3031 } 3032 3033 if ((pio = zio_unique_parent(zio)) != NULL) { 3034 /* 3035 * We're not a root i/o, so there's nothing to do 3036 * but notify our parent. Don't propagate errors 3037 * upward since we haven't permanently failed yet. 3038 */ 3039 ASSERT(!(zio->io_flags & ZIO_FLAG_GODFATHER)); 3040 zio->io_flags |= ZIO_FLAG_DONT_PROPAGATE; 3041 zio_notify_parent(pio, zio, ZIO_WAIT_DONE); 3042 } else if (zio->io_reexecute & ZIO_REEXECUTE_SUSPEND) { 3043 /* 3044 * We'd fail again if we reexecuted now, so suspend 3045 * until conditions improve (e.g. device comes online). 3046 */ 3047 zio_suspend(spa, zio); 3048 } else { 3049 /* 3050 * Reexecution is potentially a huge amount of work. 3051 * Hand it off to the otherwise-unused claim taskq. 3052 */ 3053 ASSERT(zio->io_tqent.tqent_next == NULL); 3054 spa_taskq_dispatch_ent(spa, ZIO_TYPE_CLAIM, 3055 ZIO_TASKQ_ISSUE, (task_func_t *)zio_reexecute, zio, 3056 0, &zio->io_tqent); 3057 } 3058 return (ZIO_PIPELINE_STOP); 3059 } 3060 3061 ASSERT(zio->io_child_count == 0); 3062 ASSERT(zio->io_reexecute == 0); 3063 ASSERT(zio->io_error == 0 || (zio->io_flags & ZIO_FLAG_CANFAIL)); 3064 3065 /* 3066 * Report any checksum errors, since the I/O is complete. 3067 */ 3068 while (zio->io_cksum_report != NULL) { 3069 zio_cksum_report_t *zcr = zio->io_cksum_report; 3070 zio->io_cksum_report = zcr->zcr_next; 3071 zcr->zcr_next = NULL; 3072 zcr->zcr_finish(zcr, NULL); 3073 zfs_ereport_free_checksum(zcr); 3074 } 3075 3076 /* 3077 * It is the responsibility of the done callback to ensure that this 3078 * particular zio is no longer discoverable for adoption, and as 3079 * such, cannot acquire any new parents. 3080 */ 3081 if (zio->io_done) 3082 zio->io_done(zio); 3083 3084 mutex_enter(&zio->io_lock); 3085 zio->io_state[ZIO_WAIT_DONE] = 1; 3086 mutex_exit(&zio->io_lock); 3087 3088 for (pio = zio_walk_parents(zio); pio != NULL; pio = pio_next) { 3089 zio_link_t *zl = zio->io_walk_link; 3090 pio_next = zio_walk_parents(zio); 3091 zio_remove_child(pio, zio, zl); 3092 zio_notify_parent(pio, zio, ZIO_WAIT_DONE); 3093 } 3094 3095 if (zio->io_waiter != NULL) { 3096 mutex_enter(&zio->io_lock); 3097 zio->io_executor = NULL; 3098 cv_broadcast(&zio->io_cv); 3099 mutex_exit(&zio->io_lock); 3100 } else { 3101 zio_destroy(zio); 3102 } 3103 3104 return (ZIO_PIPELINE_STOP); 3105 } 3106 3107 /* 3108 * ========================================================================== 3109 * I/O pipeline definition 3110 * ========================================================================== 3111 */ 3112 static zio_pipe_stage_t *zio_pipeline[] = { 3113 NULL, 3114 zio_read_bp_init, 3115 zio_free_bp_init, 3116 zio_issue_async, 3117 zio_write_bp_init, 3118 zio_checksum_generate, 3119 zio_nop_write, 3120 zio_ddt_read_start, 3121 zio_ddt_read_done, 3122 zio_ddt_write, 3123 zio_ddt_free, 3124 zio_gang_assemble, 3125 zio_gang_issue, 3126 zio_dva_allocate, 3127 zio_dva_free, 3128 zio_dva_claim, 3129 zio_ready, 3130 zio_vdev_io_start, 3131 zio_vdev_io_done, 3132 zio_vdev_io_assess, 3133 zio_checksum_verify, 3134 zio_done 3135 }; 3136 3137 /* dnp is the dnode for zb1->zb_object */ 3138 boolean_t 3139 zbookmark_is_before(const dnode_phys_t *dnp, const zbookmark_t *zb1, 3140 const zbookmark_t *zb2) 3141 { 3142 uint64_t zb1nextL0, zb2thisobj; 3143 3144 ASSERT(zb1->zb_objset == zb2->zb_objset); 3145 ASSERT(zb2->zb_level == 0); 3146 3147 /* 3148 * A bookmark in the deadlist is considered to be after 3149 * everything else. 3150 */ 3151 if (zb2->zb_object == DMU_DEADLIST_OBJECT) 3152 return (B_TRUE); 3153 3154 /* The objset_phys_t isn't before anything. */ 3155 if (dnp == NULL) 3156 return (B_FALSE); 3157 3158 zb1nextL0 = (zb1->zb_blkid + 1) << 3159 ((zb1->zb_level) * (dnp->dn_indblkshift - SPA_BLKPTRSHIFT)); 3160 3161 zb2thisobj = zb2->zb_object ? zb2->zb_object : 3162 zb2->zb_blkid << (DNODE_BLOCK_SHIFT - DNODE_SHIFT); 3163 3164 if (zb1->zb_object == DMU_META_DNODE_OBJECT) { 3165 uint64_t nextobj = zb1nextL0 * 3166 (dnp->dn_datablkszsec << SPA_MINBLOCKSHIFT) >> DNODE_SHIFT; 3167 return (nextobj <= zb2thisobj); 3168 } 3169 3170 if (zb1->zb_object < zb2thisobj) 3171 return (B_TRUE); 3172 if (zb1->zb_object > zb2thisobj) 3173 return (B_FALSE); 3174 if (zb2->zb_object == DMU_META_DNODE_OBJECT) 3175 return (B_FALSE); 3176 return (zb1nextL0 <= zb2->zb_blkid); 3177 } 3178