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 */ 24 25 #include <sys/zfs_context.h> 26 #include <sys/fm/fs/zfs.h> 27 #include <sys/spa.h> 28 #include <sys/txg.h> 29 #include <sys/spa_impl.h> 30 #include <sys/vdev_impl.h> 31 #include <sys/zio_impl.h> 32 #include <sys/zio_compress.h> 33 #include <sys/zio_checksum.h> 34 #include <sys/dmu_objset.h> 35 #include <sys/arc.h> 36 #include <sys/ddt.h> 37 38 /* 39 * ========================================================================== 40 * I/O priority table 41 * ========================================================================== 42 */ 43 uint8_t zio_priority_table[ZIO_PRIORITY_TABLE_SIZE] = { 44 0, /* ZIO_PRIORITY_NOW */ 45 0, /* ZIO_PRIORITY_SYNC_READ */ 46 0, /* ZIO_PRIORITY_SYNC_WRITE */ 47 0, /* ZIO_PRIORITY_LOG_WRITE */ 48 1, /* ZIO_PRIORITY_CACHE_FILL */ 49 1, /* ZIO_PRIORITY_AGG */ 50 4, /* ZIO_PRIORITY_FREE */ 51 4, /* ZIO_PRIORITY_ASYNC_WRITE */ 52 6, /* ZIO_PRIORITY_ASYNC_READ */ 53 10, /* ZIO_PRIORITY_RESILVER */ 54 20, /* ZIO_PRIORITY_SCRUB */ 55 2, /* ZIO_PRIORITY_DDT_PREFETCH */ 56 }; 57 58 /* 59 * ========================================================================== 60 * I/O type descriptions 61 * ========================================================================== 62 */ 63 char *zio_type_name[ZIO_TYPES] = { 64 "zio_null", "zio_read", "zio_write", "zio_free", "zio_claim", 65 "zio_ioctl" 66 }; 67 68 /* 69 * ========================================================================== 70 * I/O kmem caches 71 * ========================================================================== 72 */ 73 kmem_cache_t *zio_cache; 74 kmem_cache_t *zio_link_cache; 75 kmem_cache_t *zio_buf_cache[SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT]; 76 kmem_cache_t *zio_data_buf_cache[SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT]; 77 78 #ifdef _KERNEL 79 extern vmem_t *zio_alloc_arena; 80 #endif 81 82 /* 83 * An allocating zio is one that either currently has the DVA allocate 84 * stage set or will have it later in its lifetime. 85 */ 86 #define IO_IS_ALLOCATING(zio) ((zio)->io_orig_pipeline & ZIO_STAGE_DVA_ALLOCATE) 87 88 boolean_t zio_requeue_io_start_cut_in_line = B_TRUE; 89 90 #ifdef ZFS_DEBUG 91 int zio_buf_debug_limit = 16384; 92 #else 93 int zio_buf_debug_limit = 0; 94 #endif 95 96 void 97 zio_init(void) 98 { 99 size_t c; 100 vmem_t *data_alloc_arena = NULL; 101 102 #ifdef _KERNEL 103 data_alloc_arena = zio_alloc_arena; 104 #endif 105 zio_cache = kmem_cache_create("zio_cache", 106 sizeof (zio_t), 0, NULL, NULL, NULL, NULL, NULL, 0); 107 zio_link_cache = kmem_cache_create("zio_link_cache", 108 sizeof (zio_link_t), 0, NULL, NULL, NULL, NULL, NULL, 0); 109 110 /* 111 * For small buffers, we want a cache for each multiple of 112 * SPA_MINBLOCKSIZE. For medium-size buffers, we want a cache 113 * for each quarter-power of 2. For large buffers, we want 114 * a cache for each multiple of PAGESIZE. 115 */ 116 for (c = 0; c < SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT; c++) { 117 size_t size = (c + 1) << SPA_MINBLOCKSHIFT; 118 size_t p2 = size; 119 size_t align = 0; 120 121 while (p2 & (p2 - 1)) 122 p2 &= p2 - 1; 123 124 if (size <= 4 * SPA_MINBLOCKSIZE) { 125 align = SPA_MINBLOCKSIZE; 126 } else if (P2PHASE(size, PAGESIZE) == 0) { 127 align = PAGESIZE; 128 } else if (P2PHASE(size, p2 >> 2) == 0) { 129 align = p2 >> 2; 130 } 131 132 if (align != 0) { 133 char name[36]; 134 (void) sprintf(name, "zio_buf_%lu", (ulong_t)size); 135 zio_buf_cache[c] = kmem_cache_create(name, size, 136 align, NULL, NULL, NULL, NULL, NULL, 137 size > zio_buf_debug_limit ? KMC_NODEBUG : 0); 138 139 (void) sprintf(name, "zio_data_buf_%lu", (ulong_t)size); 140 zio_data_buf_cache[c] = kmem_cache_create(name, size, 141 align, NULL, NULL, NULL, NULL, data_alloc_arena, 142 size > zio_buf_debug_limit ? KMC_NODEBUG : 0); 143 } 144 } 145 146 while (--c != 0) { 147 ASSERT(zio_buf_cache[c] != NULL); 148 if (zio_buf_cache[c - 1] == NULL) 149 zio_buf_cache[c - 1] = zio_buf_cache[c]; 150 151 ASSERT(zio_data_buf_cache[c] != NULL); 152 if (zio_data_buf_cache[c - 1] == NULL) 153 zio_data_buf_cache[c - 1] = zio_data_buf_cache[c]; 154 } 155 156 zio_inject_init(); 157 } 158 159 void 160 zio_fini(void) 161 { 162 size_t c; 163 kmem_cache_t *last_cache = NULL; 164 kmem_cache_t *last_data_cache = NULL; 165 166 for (c = 0; c < SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT; c++) { 167 if (zio_buf_cache[c] != last_cache) { 168 last_cache = zio_buf_cache[c]; 169 kmem_cache_destroy(zio_buf_cache[c]); 170 } 171 zio_buf_cache[c] = NULL; 172 173 if (zio_data_buf_cache[c] != last_data_cache) { 174 last_data_cache = zio_data_buf_cache[c]; 175 kmem_cache_destroy(zio_data_buf_cache[c]); 176 } 177 zio_data_buf_cache[c] = NULL; 178 } 179 180 kmem_cache_destroy(zio_link_cache); 181 kmem_cache_destroy(zio_cache); 182 183 zio_inject_fini(); 184 } 185 186 /* 187 * ========================================================================== 188 * Allocate and free I/O buffers 189 * ========================================================================== 190 */ 191 192 /* 193 * Use zio_buf_alloc to allocate ZFS metadata. This data will appear in a 194 * crashdump if the kernel panics, so use it judiciously. Obviously, it's 195 * useful to inspect ZFS metadata, but if possible, we should avoid keeping 196 * excess / transient data in-core during a crashdump. 197 */ 198 void * 199 zio_buf_alloc(size_t size) 200 { 201 size_t c = (size - 1) >> SPA_MINBLOCKSHIFT; 202 203 ASSERT(c < SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT); 204 205 return (kmem_cache_alloc(zio_buf_cache[c], KM_PUSHPAGE)); 206 } 207 208 /* 209 * Use zio_data_buf_alloc to allocate data. The data will not appear in a 210 * crashdump if the kernel panics. This exists so that we will limit the amount 211 * of ZFS data that shows up in a kernel crashdump. (Thus reducing the amount 212 * of kernel heap dumped to disk when the kernel panics) 213 */ 214 void * 215 zio_data_buf_alloc(size_t size) 216 { 217 size_t c = (size - 1) >> SPA_MINBLOCKSHIFT; 218 219 ASSERT(c < SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT); 220 221 return (kmem_cache_alloc(zio_data_buf_cache[c], KM_PUSHPAGE)); 222 } 223 224 void 225 zio_buf_free(void *buf, size_t size) 226 { 227 size_t c = (size - 1) >> SPA_MINBLOCKSHIFT; 228 229 ASSERT(c < SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT); 230 231 kmem_cache_free(zio_buf_cache[c], buf); 232 } 233 234 void 235 zio_data_buf_free(void *buf, size_t size) 236 { 237 size_t c = (size - 1) >> SPA_MINBLOCKSHIFT; 238 239 ASSERT(c < SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT); 240 241 kmem_cache_free(zio_data_buf_cache[c], buf); 242 } 243 244 /* 245 * ========================================================================== 246 * Push and pop I/O transform buffers 247 * ========================================================================== 248 */ 249 static void 250 zio_push_transform(zio_t *zio, void *data, uint64_t size, uint64_t bufsize, 251 zio_transform_func_t *transform) 252 { 253 zio_transform_t *zt = kmem_alloc(sizeof (zio_transform_t), KM_SLEEP); 254 255 zt->zt_orig_data = zio->io_data; 256 zt->zt_orig_size = zio->io_size; 257 zt->zt_bufsize = bufsize; 258 zt->zt_transform = transform; 259 260 zt->zt_next = zio->io_transform_stack; 261 zio->io_transform_stack = zt; 262 263 zio->io_data = data; 264 zio->io_size = size; 265 } 266 267 static void 268 zio_pop_transforms(zio_t *zio) 269 { 270 zio_transform_t *zt; 271 272 while ((zt = zio->io_transform_stack) != NULL) { 273 if (zt->zt_transform != NULL) 274 zt->zt_transform(zio, 275 zt->zt_orig_data, zt->zt_orig_size); 276 277 if (zt->zt_bufsize != 0) 278 zio_buf_free(zio->io_data, zt->zt_bufsize); 279 280 zio->io_data = zt->zt_orig_data; 281 zio->io_size = zt->zt_orig_size; 282 zio->io_transform_stack = zt->zt_next; 283 284 kmem_free(zt, sizeof (zio_transform_t)); 285 } 286 } 287 288 /* 289 * ========================================================================== 290 * I/O transform callbacks for subblocks and decompression 291 * ========================================================================== 292 */ 293 static void 294 zio_subblock(zio_t *zio, void *data, uint64_t size) 295 { 296 ASSERT(zio->io_size > size); 297 298 if (zio->io_type == ZIO_TYPE_READ) 299 bcopy(zio->io_data, data, size); 300 } 301 302 static void 303 zio_decompress(zio_t *zio, void *data, uint64_t size) 304 { 305 if (zio->io_error == 0 && 306 zio_decompress_data(BP_GET_COMPRESS(zio->io_bp), 307 zio->io_data, data, zio->io_size, size) != 0) 308 zio->io_error = EIO; 309 } 310 311 /* 312 * ========================================================================== 313 * I/O parent/child relationships and pipeline interlocks 314 * ========================================================================== 315 */ 316 /* 317 * NOTE - Callers to zio_walk_parents() and zio_walk_children must 318 * continue calling these functions until they return NULL. 319 * Otherwise, the next caller will pick up the list walk in 320 * some indeterminate state. (Otherwise every caller would 321 * have to pass in a cookie to keep the state represented by 322 * io_walk_link, which gets annoying.) 323 */ 324 zio_t * 325 zio_walk_parents(zio_t *cio) 326 { 327 zio_link_t *zl = cio->io_walk_link; 328 list_t *pl = &cio->io_parent_list; 329 330 zl = (zl == NULL) ? list_head(pl) : list_next(pl, zl); 331 cio->io_walk_link = zl; 332 333 if (zl == NULL) 334 return (NULL); 335 336 ASSERT(zl->zl_child == cio); 337 return (zl->zl_parent); 338 } 339 340 zio_t * 341 zio_walk_children(zio_t *pio) 342 { 343 zio_link_t *zl = pio->io_walk_link; 344 list_t *cl = &pio->io_child_list; 345 346 zl = (zl == NULL) ? list_head(cl) : list_next(cl, zl); 347 pio->io_walk_link = zl; 348 349 if (zl == NULL) 350 return (NULL); 351 352 ASSERT(zl->zl_parent == pio); 353 return (zl->zl_child); 354 } 355 356 zio_t * 357 zio_unique_parent(zio_t *cio) 358 { 359 zio_t *pio = zio_walk_parents(cio); 360 361 VERIFY(zio_walk_parents(cio) == NULL); 362 return (pio); 363 } 364 365 void 366 zio_add_child(zio_t *pio, zio_t *cio) 367 { 368 zio_link_t *zl = kmem_cache_alloc(zio_link_cache, KM_SLEEP); 369 370 /* 371 * Logical I/Os can have logical, gang, or vdev children. 372 * Gang I/Os can have gang or vdev children. 373 * Vdev I/Os can only have vdev children. 374 * The following ASSERT captures all of these constraints. 375 */ 376 ASSERT(cio->io_child_type <= pio->io_child_type); 377 378 zl->zl_parent = pio; 379 zl->zl_child = cio; 380 381 mutex_enter(&cio->io_lock); 382 mutex_enter(&pio->io_lock); 383 384 ASSERT(pio->io_state[ZIO_WAIT_DONE] == 0); 385 386 for (int w = 0; w < ZIO_WAIT_TYPES; w++) 387 pio->io_children[cio->io_child_type][w] += !cio->io_state[w]; 388 389 list_insert_head(&pio->io_child_list, zl); 390 list_insert_head(&cio->io_parent_list, zl); 391 392 pio->io_child_count++; 393 cio->io_parent_count++; 394 395 mutex_exit(&pio->io_lock); 396 mutex_exit(&cio->io_lock); 397 } 398 399 static void 400 zio_remove_child(zio_t *pio, zio_t *cio, zio_link_t *zl) 401 { 402 ASSERT(zl->zl_parent == pio); 403 ASSERT(zl->zl_child == cio); 404 405 mutex_enter(&cio->io_lock); 406 mutex_enter(&pio->io_lock); 407 408 list_remove(&pio->io_child_list, zl); 409 list_remove(&cio->io_parent_list, zl); 410 411 pio->io_child_count--; 412 cio->io_parent_count--; 413 414 mutex_exit(&pio->io_lock); 415 mutex_exit(&cio->io_lock); 416 417 kmem_cache_free(zio_link_cache, zl); 418 } 419 420 static boolean_t 421 zio_wait_for_children(zio_t *zio, enum zio_child child, enum zio_wait_type wait) 422 { 423 uint64_t *countp = &zio->io_children[child][wait]; 424 boolean_t waiting = B_FALSE; 425 426 mutex_enter(&zio->io_lock); 427 ASSERT(zio->io_stall == NULL); 428 if (*countp != 0) { 429 zio->io_stage >>= 1; 430 zio->io_stall = countp; 431 waiting = B_TRUE; 432 } 433 mutex_exit(&zio->io_lock); 434 435 return (waiting); 436 } 437 438 static void 439 zio_notify_parent(zio_t *pio, zio_t *zio, enum zio_wait_type wait) 440 { 441 uint64_t *countp = &pio->io_children[zio->io_child_type][wait]; 442 int *errorp = &pio->io_child_error[zio->io_child_type]; 443 444 mutex_enter(&pio->io_lock); 445 if (zio->io_error && !(zio->io_flags & ZIO_FLAG_DONT_PROPAGATE)) 446 *errorp = zio_worst_error(*errorp, zio->io_error); 447 pio->io_reexecute |= zio->io_reexecute; 448 ASSERT3U(*countp, >, 0); 449 if (--*countp == 0 && pio->io_stall == countp) { 450 pio->io_stall = NULL; 451 mutex_exit(&pio->io_lock); 452 zio_execute(pio); 453 } else { 454 mutex_exit(&pio->io_lock); 455 } 456 } 457 458 static void 459 zio_inherit_child_errors(zio_t *zio, enum zio_child c) 460 { 461 if (zio->io_child_error[c] != 0 && zio->io_error == 0) 462 zio->io_error = zio->io_child_error[c]; 463 } 464 465 /* 466 * ========================================================================== 467 * Create the various types of I/O (read, write, free, etc) 468 * ========================================================================== 469 */ 470 static zio_t * 471 zio_create(zio_t *pio, spa_t *spa, uint64_t txg, const blkptr_t *bp, 472 void *data, uint64_t size, zio_done_func_t *done, void *private, 473 zio_type_t type, int priority, enum zio_flag flags, 474 vdev_t *vd, uint64_t offset, const zbookmark_t *zb, 475 enum zio_stage stage, enum zio_stage pipeline) 476 { 477 zio_t *zio; 478 479 ASSERT3U(size, <=, SPA_MAXBLOCKSIZE); 480 ASSERT(P2PHASE(size, SPA_MINBLOCKSIZE) == 0); 481 ASSERT(P2PHASE(offset, SPA_MINBLOCKSIZE) == 0); 482 483 ASSERT(!vd || spa_config_held(spa, SCL_STATE_ALL, RW_READER)); 484 ASSERT(!bp || !(flags & ZIO_FLAG_CONFIG_WRITER)); 485 ASSERT(vd || stage == ZIO_STAGE_OPEN); 486 487 zio = kmem_cache_alloc(zio_cache, KM_SLEEP); 488 bzero(zio, sizeof (zio_t)); 489 490 mutex_init(&zio->io_lock, NULL, MUTEX_DEFAULT, NULL); 491 cv_init(&zio->io_cv, NULL, CV_DEFAULT, NULL); 492 493 list_create(&zio->io_parent_list, sizeof (zio_link_t), 494 offsetof(zio_link_t, zl_parent_node)); 495 list_create(&zio->io_child_list, sizeof (zio_link_t), 496 offsetof(zio_link_t, zl_child_node)); 497 498 if (vd != NULL) 499 zio->io_child_type = ZIO_CHILD_VDEV; 500 else if (flags & ZIO_FLAG_GANG_CHILD) 501 zio->io_child_type = ZIO_CHILD_GANG; 502 else if (flags & ZIO_FLAG_DDT_CHILD) 503 zio->io_child_type = ZIO_CHILD_DDT; 504 else 505 zio->io_child_type = ZIO_CHILD_LOGICAL; 506 507 if (bp != NULL) { 508 zio->io_bp = (blkptr_t *)bp; 509 zio->io_bp_copy = *bp; 510 zio->io_bp_orig = *bp; 511 if (type != ZIO_TYPE_WRITE || 512 zio->io_child_type == ZIO_CHILD_DDT) 513 zio->io_bp = &zio->io_bp_copy; /* so caller can free */ 514 if (zio->io_child_type == ZIO_CHILD_LOGICAL) 515 zio->io_logical = zio; 516 if (zio->io_child_type > ZIO_CHILD_GANG && BP_IS_GANG(bp)) 517 pipeline |= ZIO_GANG_STAGES; 518 } 519 520 zio->io_spa = spa; 521 zio->io_txg = txg; 522 zio->io_done = done; 523 zio->io_private = private; 524 zio->io_type = type; 525 zio->io_priority = priority; 526 zio->io_vd = vd; 527 zio->io_offset = offset; 528 zio->io_orig_data = zio->io_data = data; 529 zio->io_orig_size = zio->io_size = size; 530 zio->io_orig_flags = zio->io_flags = flags; 531 zio->io_orig_stage = zio->io_stage = stage; 532 zio->io_orig_pipeline = zio->io_pipeline = pipeline; 533 534 zio->io_state[ZIO_WAIT_READY] = (stage >= ZIO_STAGE_READY); 535 zio->io_state[ZIO_WAIT_DONE] = (stage >= ZIO_STAGE_DONE); 536 537 if (zb != NULL) 538 zio->io_bookmark = *zb; 539 540 if (pio != NULL) { 541 if (zio->io_logical == NULL) 542 zio->io_logical = pio->io_logical; 543 if (zio->io_child_type == ZIO_CHILD_GANG) 544 zio->io_gang_leader = pio->io_gang_leader; 545 zio_add_child(pio, zio); 546 } 547 548 return (zio); 549 } 550 551 static void 552 zio_destroy(zio_t *zio) 553 { 554 list_destroy(&zio->io_parent_list); 555 list_destroy(&zio->io_child_list); 556 mutex_destroy(&zio->io_lock); 557 cv_destroy(&zio->io_cv); 558 kmem_cache_free(zio_cache, zio); 559 } 560 561 zio_t * 562 zio_null(zio_t *pio, spa_t *spa, vdev_t *vd, zio_done_func_t *done, 563 void *private, enum zio_flag flags) 564 { 565 zio_t *zio; 566 567 zio = zio_create(pio, spa, 0, NULL, NULL, 0, done, private, 568 ZIO_TYPE_NULL, ZIO_PRIORITY_NOW, flags, vd, 0, NULL, 569 ZIO_STAGE_OPEN, ZIO_INTERLOCK_PIPELINE); 570 571 return (zio); 572 } 573 574 zio_t * 575 zio_root(spa_t *spa, zio_done_func_t *done, void *private, enum zio_flag flags) 576 { 577 return (zio_null(NULL, spa, NULL, done, private, flags)); 578 } 579 580 zio_t * 581 zio_read(zio_t *pio, spa_t *spa, const blkptr_t *bp, 582 void *data, uint64_t size, zio_done_func_t *done, void *private, 583 int priority, enum zio_flag flags, const zbookmark_t *zb) 584 { 585 zio_t *zio; 586 587 zio = zio_create(pio, spa, BP_PHYSICAL_BIRTH(bp), bp, 588 data, size, done, private, 589 ZIO_TYPE_READ, priority, flags, NULL, 0, zb, 590 ZIO_STAGE_OPEN, (flags & ZIO_FLAG_DDT_CHILD) ? 591 ZIO_DDT_CHILD_READ_PIPELINE : ZIO_READ_PIPELINE); 592 593 return (zio); 594 } 595 596 zio_t * 597 zio_write(zio_t *pio, spa_t *spa, uint64_t txg, blkptr_t *bp, 598 void *data, uint64_t size, const zio_prop_t *zp, 599 zio_done_func_t *ready, zio_done_func_t *done, void *private, 600 int priority, enum zio_flag flags, const zbookmark_t *zb) 601 { 602 zio_t *zio; 603 604 ASSERT(zp->zp_checksum >= ZIO_CHECKSUM_OFF && 605 zp->zp_checksum < ZIO_CHECKSUM_FUNCTIONS && 606 zp->zp_compress >= ZIO_COMPRESS_OFF && 607 zp->zp_compress < ZIO_COMPRESS_FUNCTIONS && 608 zp->zp_type < DMU_OT_NUMTYPES && 609 zp->zp_level < 32 && 610 zp->zp_copies > 0 && 611 zp->zp_copies <= spa_max_replication(spa) && 612 zp->zp_dedup <= 1 && 613 zp->zp_dedup_verify <= 1); 614 615 zio = zio_create(pio, spa, txg, bp, data, size, done, private, 616 ZIO_TYPE_WRITE, priority, flags, NULL, 0, zb, 617 ZIO_STAGE_OPEN, (flags & ZIO_FLAG_DDT_CHILD) ? 618 ZIO_DDT_CHILD_WRITE_PIPELINE : ZIO_WRITE_PIPELINE); 619 620 zio->io_ready = ready; 621 zio->io_prop = *zp; 622 623 return (zio); 624 } 625 626 zio_t * 627 zio_rewrite(zio_t *pio, spa_t *spa, uint64_t txg, blkptr_t *bp, void *data, 628 uint64_t size, zio_done_func_t *done, void *private, int priority, 629 enum zio_flag flags, zbookmark_t *zb) 630 { 631 zio_t *zio; 632 633 zio = zio_create(pio, spa, txg, bp, data, size, done, private, 634 ZIO_TYPE_WRITE, priority, flags, NULL, 0, zb, 635 ZIO_STAGE_OPEN, ZIO_REWRITE_PIPELINE); 636 637 return (zio); 638 } 639 640 void 641 zio_write_override(zio_t *zio, blkptr_t *bp, int copies) 642 { 643 ASSERT(zio->io_type == ZIO_TYPE_WRITE); 644 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL); 645 ASSERT(zio->io_stage == ZIO_STAGE_OPEN); 646 ASSERT(zio->io_txg == spa_syncing_txg(zio->io_spa)); 647 648 zio->io_prop.zp_copies = copies; 649 zio->io_bp_override = bp; 650 } 651 652 void 653 zio_free(spa_t *spa, uint64_t txg, const blkptr_t *bp) 654 { 655 bplist_append(&spa->spa_free_bplist[txg & TXG_MASK], bp); 656 } 657 658 zio_t * 659 zio_free_sync(zio_t *pio, spa_t *spa, uint64_t txg, const blkptr_t *bp, 660 enum zio_flag flags) 661 { 662 zio_t *zio; 663 664 dprintf_bp(bp, "freeing in txg %llu, pass %u", 665 (longlong_t)txg, spa->spa_sync_pass); 666 667 ASSERT(!BP_IS_HOLE(bp)); 668 ASSERT(spa_syncing_txg(spa) == txg); 669 ASSERT(spa_sync_pass(spa) <= SYNC_PASS_DEFERRED_FREE); 670 671 zio = zio_create(pio, spa, txg, bp, NULL, BP_GET_PSIZE(bp), 672 NULL, NULL, ZIO_TYPE_FREE, ZIO_PRIORITY_FREE, flags, 673 NULL, 0, NULL, ZIO_STAGE_OPEN, ZIO_FREE_PIPELINE); 674 675 return (zio); 676 } 677 678 zio_t * 679 zio_claim(zio_t *pio, spa_t *spa, uint64_t txg, const blkptr_t *bp, 680 zio_done_func_t *done, void *private, enum zio_flag flags) 681 { 682 zio_t *zio; 683 684 /* 685 * A claim is an allocation of a specific block. Claims are needed 686 * to support immediate writes in the intent log. The issue is that 687 * immediate writes contain committed data, but in a txg that was 688 * *not* committed. Upon opening the pool after an unclean shutdown, 689 * the intent log claims all blocks that contain immediate write data 690 * so that the SPA knows they're in use. 691 * 692 * All claims *must* be resolved in the first txg -- before the SPA 693 * starts allocating blocks -- so that nothing is allocated twice. 694 * If txg == 0 we just verify that the block is claimable. 695 */ 696 ASSERT3U(spa->spa_uberblock.ub_rootbp.blk_birth, <, spa_first_txg(spa)); 697 ASSERT(txg == spa_first_txg(spa) || txg == 0); 698 ASSERT(!BP_GET_DEDUP(bp) || !spa_writeable(spa)); /* zdb(1M) */ 699 700 zio = zio_create(pio, spa, txg, bp, NULL, BP_GET_PSIZE(bp), 701 done, private, ZIO_TYPE_CLAIM, ZIO_PRIORITY_NOW, flags, 702 NULL, 0, NULL, ZIO_STAGE_OPEN, ZIO_CLAIM_PIPELINE); 703 704 return (zio); 705 } 706 707 zio_t * 708 zio_ioctl(zio_t *pio, spa_t *spa, vdev_t *vd, int cmd, 709 zio_done_func_t *done, void *private, int priority, enum zio_flag flags) 710 { 711 zio_t *zio; 712 int c; 713 714 if (vd->vdev_children == 0) { 715 zio = zio_create(pio, spa, 0, NULL, NULL, 0, done, private, 716 ZIO_TYPE_IOCTL, priority, flags, vd, 0, NULL, 717 ZIO_STAGE_OPEN, ZIO_IOCTL_PIPELINE); 718 719 zio->io_cmd = cmd; 720 } else { 721 zio = zio_null(pio, spa, NULL, NULL, NULL, flags); 722 723 for (c = 0; c < vd->vdev_children; c++) 724 zio_nowait(zio_ioctl(zio, spa, vd->vdev_child[c], cmd, 725 done, private, priority, flags)); 726 } 727 728 return (zio); 729 } 730 731 zio_t * 732 zio_read_phys(zio_t *pio, vdev_t *vd, uint64_t offset, uint64_t size, 733 void *data, int checksum, zio_done_func_t *done, void *private, 734 int priority, enum zio_flag flags, boolean_t labels) 735 { 736 zio_t *zio; 737 738 ASSERT(vd->vdev_children == 0); 739 ASSERT(!labels || offset + size <= VDEV_LABEL_START_SIZE || 740 offset >= vd->vdev_psize - VDEV_LABEL_END_SIZE); 741 ASSERT3U(offset + size, <=, vd->vdev_psize); 742 743 zio = zio_create(pio, vd->vdev_spa, 0, NULL, data, size, done, private, 744 ZIO_TYPE_READ, priority, flags, vd, offset, NULL, 745 ZIO_STAGE_OPEN, ZIO_READ_PHYS_PIPELINE); 746 747 zio->io_prop.zp_checksum = checksum; 748 749 return (zio); 750 } 751 752 zio_t * 753 zio_write_phys(zio_t *pio, vdev_t *vd, uint64_t offset, uint64_t size, 754 void *data, int checksum, zio_done_func_t *done, void *private, 755 int priority, enum zio_flag flags, boolean_t labels) 756 { 757 zio_t *zio; 758 759 ASSERT(vd->vdev_children == 0); 760 ASSERT(!labels || offset + size <= VDEV_LABEL_START_SIZE || 761 offset >= vd->vdev_psize - VDEV_LABEL_END_SIZE); 762 ASSERT3U(offset + size, <=, vd->vdev_psize); 763 764 zio = zio_create(pio, vd->vdev_spa, 0, NULL, data, size, done, private, 765 ZIO_TYPE_WRITE, priority, flags, vd, offset, NULL, 766 ZIO_STAGE_OPEN, ZIO_WRITE_PHYS_PIPELINE); 767 768 zio->io_prop.zp_checksum = checksum; 769 770 if (zio_checksum_table[checksum].ci_eck) { 771 /* 772 * zec checksums are necessarily destructive -- they modify 773 * the end of the write buffer to hold the verifier/checksum. 774 * Therefore, we must make a local copy in case the data is 775 * being written to multiple places in parallel. 776 */ 777 void *wbuf = zio_buf_alloc(size); 778 bcopy(data, wbuf, size); 779 zio_push_transform(zio, wbuf, size, size, NULL); 780 } 781 782 return (zio); 783 } 784 785 /* 786 * Create a child I/O to do some work for us. 787 */ 788 zio_t * 789 zio_vdev_child_io(zio_t *pio, blkptr_t *bp, vdev_t *vd, uint64_t offset, 790 void *data, uint64_t size, int type, int priority, enum zio_flag flags, 791 zio_done_func_t *done, void *private) 792 { 793 enum zio_stage pipeline = ZIO_VDEV_CHILD_PIPELINE; 794 zio_t *zio; 795 796 ASSERT(vd->vdev_parent == 797 (pio->io_vd ? pio->io_vd : pio->io_spa->spa_root_vdev)); 798 799 if (type == ZIO_TYPE_READ && bp != NULL) { 800 /* 801 * If we have the bp, then the child should perform the 802 * checksum and the parent need not. This pushes error 803 * detection as close to the leaves as possible and 804 * eliminates redundant checksums in the interior nodes. 805 */ 806 pipeline |= ZIO_STAGE_CHECKSUM_VERIFY; 807 pio->io_pipeline &= ~ZIO_STAGE_CHECKSUM_VERIFY; 808 } 809 810 if (vd->vdev_children == 0) 811 offset += VDEV_LABEL_START_SIZE; 812 813 flags |= ZIO_VDEV_CHILD_FLAGS(pio) | ZIO_FLAG_DONT_PROPAGATE; 814 815 /* 816 * If we've decided to do a repair, the write is not speculative -- 817 * even if the original read was. 818 */ 819 if (flags & ZIO_FLAG_IO_REPAIR) 820 flags &= ~ZIO_FLAG_SPECULATIVE; 821 822 zio = zio_create(pio, pio->io_spa, pio->io_txg, bp, data, size, 823 done, private, type, priority, flags, vd, offset, &pio->io_bookmark, 824 ZIO_STAGE_VDEV_IO_START >> 1, pipeline); 825 826 return (zio); 827 } 828 829 zio_t * 830 zio_vdev_delegated_io(vdev_t *vd, uint64_t offset, void *data, uint64_t size, 831 int type, int priority, enum zio_flag flags, 832 zio_done_func_t *done, void *private) 833 { 834 zio_t *zio; 835 836 ASSERT(vd->vdev_ops->vdev_op_leaf); 837 838 zio = zio_create(NULL, vd->vdev_spa, 0, NULL, 839 data, size, done, private, type, priority, 840 flags | ZIO_FLAG_CANFAIL | ZIO_FLAG_DONT_RETRY, 841 vd, offset, NULL, 842 ZIO_STAGE_VDEV_IO_START >> 1, ZIO_VDEV_CHILD_PIPELINE); 843 844 return (zio); 845 } 846 847 void 848 zio_flush(zio_t *zio, vdev_t *vd) 849 { 850 zio_nowait(zio_ioctl(zio, zio->io_spa, vd, DKIOCFLUSHWRITECACHE, 851 NULL, NULL, ZIO_PRIORITY_NOW, 852 ZIO_FLAG_CANFAIL | ZIO_FLAG_DONT_PROPAGATE | ZIO_FLAG_DONT_RETRY)); 853 } 854 855 void 856 zio_shrink(zio_t *zio, uint64_t size) 857 { 858 ASSERT(zio->io_executor == NULL); 859 ASSERT(zio->io_orig_size == zio->io_size); 860 ASSERT(size <= zio->io_size); 861 862 /* 863 * We don't shrink for raidz because of problems with the 864 * reconstruction when reading back less than the block size. 865 * Note, BP_IS_RAIDZ() assumes no compression. 866 */ 867 ASSERT(BP_GET_COMPRESS(zio->io_bp) == ZIO_COMPRESS_OFF); 868 if (!BP_IS_RAIDZ(zio->io_bp)) 869 zio->io_orig_size = zio->io_size = size; 870 } 871 872 /* 873 * ========================================================================== 874 * Prepare to read and write logical blocks 875 * ========================================================================== 876 */ 877 878 static int 879 zio_read_bp_init(zio_t *zio) 880 { 881 blkptr_t *bp = zio->io_bp; 882 883 if (BP_GET_COMPRESS(bp) != ZIO_COMPRESS_OFF && 884 zio->io_child_type == ZIO_CHILD_LOGICAL && 885 !(zio->io_flags & ZIO_FLAG_RAW)) { 886 uint64_t psize = BP_GET_PSIZE(bp); 887 void *cbuf = zio_buf_alloc(psize); 888 889 zio_push_transform(zio, cbuf, psize, psize, zio_decompress); 890 } 891 892 if (!dmu_ot[BP_GET_TYPE(bp)].ot_metadata && BP_GET_LEVEL(bp) == 0) 893 zio->io_flags |= ZIO_FLAG_DONT_CACHE; 894 895 if (BP_GET_TYPE(bp) == DMU_OT_DDT_ZAP) 896 zio->io_flags |= ZIO_FLAG_DONT_CACHE; 897 898 if (BP_GET_DEDUP(bp) && zio->io_child_type == ZIO_CHILD_LOGICAL) 899 zio->io_pipeline = ZIO_DDT_READ_PIPELINE; 900 901 return (ZIO_PIPELINE_CONTINUE); 902 } 903 904 static int 905 zio_write_bp_init(zio_t *zio) 906 { 907 spa_t *spa = zio->io_spa; 908 zio_prop_t *zp = &zio->io_prop; 909 enum zio_compress compress = zp->zp_compress; 910 blkptr_t *bp = zio->io_bp; 911 uint64_t lsize = zio->io_size; 912 uint64_t psize = lsize; 913 int pass = 1; 914 915 /* 916 * If our children haven't all reached the ready stage, 917 * wait for them and then repeat this pipeline stage. 918 */ 919 if (zio_wait_for_children(zio, ZIO_CHILD_GANG, ZIO_WAIT_READY) || 920 zio_wait_for_children(zio, ZIO_CHILD_LOGICAL, ZIO_WAIT_READY)) 921 return (ZIO_PIPELINE_STOP); 922 923 if (!IO_IS_ALLOCATING(zio)) 924 return (ZIO_PIPELINE_CONTINUE); 925 926 ASSERT(zio->io_child_type != ZIO_CHILD_DDT); 927 928 if (zio->io_bp_override) { 929 ASSERT(bp->blk_birth != zio->io_txg); 930 ASSERT(BP_GET_DEDUP(zio->io_bp_override) == 0); 931 932 *bp = *zio->io_bp_override; 933 zio->io_pipeline = ZIO_INTERLOCK_PIPELINE; 934 935 if (BP_IS_HOLE(bp) || !zp->zp_dedup) 936 return (ZIO_PIPELINE_CONTINUE); 937 938 ASSERT(zio_checksum_table[zp->zp_checksum].ci_dedup || 939 zp->zp_dedup_verify); 940 941 if (BP_GET_CHECKSUM(bp) == zp->zp_checksum) { 942 BP_SET_DEDUP(bp, 1); 943 zio->io_pipeline |= ZIO_STAGE_DDT_WRITE; 944 return (ZIO_PIPELINE_CONTINUE); 945 } 946 zio->io_bp_override = NULL; 947 BP_ZERO(bp); 948 } 949 950 if (bp->blk_birth == zio->io_txg) { 951 /* 952 * We're rewriting an existing block, which means we're 953 * working on behalf of spa_sync(). For spa_sync() to 954 * converge, it must eventually be the case that we don't 955 * have to allocate new blocks. But compression changes 956 * the blocksize, which forces a reallocate, and makes 957 * convergence take longer. Therefore, after the first 958 * few passes, stop compressing to ensure convergence. 959 */ 960 pass = spa_sync_pass(spa); 961 962 ASSERT(zio->io_txg == spa_syncing_txg(spa)); 963 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL); 964 ASSERT(!BP_GET_DEDUP(bp)); 965 966 if (pass > SYNC_PASS_DONT_COMPRESS) 967 compress = ZIO_COMPRESS_OFF; 968 969 /* Make sure someone doesn't change their mind on overwrites */ 970 ASSERT(MIN(zp->zp_copies + BP_IS_GANG(bp), 971 spa_max_replication(spa)) == BP_GET_NDVAS(bp)); 972 } 973 974 if (compress != ZIO_COMPRESS_OFF) { 975 void *cbuf = zio_buf_alloc(lsize); 976 psize = zio_compress_data(compress, zio->io_data, cbuf, lsize); 977 if (psize == 0 || psize == lsize) { 978 compress = ZIO_COMPRESS_OFF; 979 zio_buf_free(cbuf, lsize); 980 } else { 981 ASSERT(psize < lsize); 982 zio_push_transform(zio, cbuf, psize, lsize, NULL); 983 } 984 } 985 986 /* 987 * The final pass of spa_sync() must be all rewrites, but the first 988 * few passes offer a trade-off: allocating blocks defers convergence, 989 * but newly allocated blocks are sequential, so they can be written 990 * to disk faster. Therefore, we allow the first few passes of 991 * spa_sync() to allocate new blocks, but force rewrites after that. 992 * There should only be a handful of blocks after pass 1 in any case. 993 */ 994 if (bp->blk_birth == zio->io_txg && BP_GET_PSIZE(bp) == psize && 995 pass > SYNC_PASS_REWRITE) { 996 ASSERT(psize != 0); 997 enum zio_stage gang_stages = zio->io_pipeline & ZIO_GANG_STAGES; 998 zio->io_pipeline = ZIO_REWRITE_PIPELINE | gang_stages; 999 zio->io_flags |= ZIO_FLAG_IO_REWRITE; 1000 } else { 1001 BP_ZERO(bp); 1002 zio->io_pipeline = ZIO_WRITE_PIPELINE; 1003 } 1004 1005 if (psize == 0) { 1006 zio->io_pipeline = ZIO_INTERLOCK_PIPELINE; 1007 } else { 1008 ASSERT(zp->zp_checksum != ZIO_CHECKSUM_GANG_HEADER); 1009 BP_SET_LSIZE(bp, lsize); 1010 BP_SET_PSIZE(bp, psize); 1011 BP_SET_COMPRESS(bp, compress); 1012 BP_SET_CHECKSUM(bp, zp->zp_checksum); 1013 BP_SET_TYPE(bp, zp->zp_type); 1014 BP_SET_LEVEL(bp, zp->zp_level); 1015 BP_SET_DEDUP(bp, zp->zp_dedup); 1016 BP_SET_BYTEORDER(bp, ZFS_HOST_BYTEORDER); 1017 if (zp->zp_dedup) { 1018 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL); 1019 ASSERT(!(zio->io_flags & ZIO_FLAG_IO_REWRITE)); 1020 zio->io_pipeline = ZIO_DDT_WRITE_PIPELINE; 1021 } 1022 } 1023 1024 return (ZIO_PIPELINE_CONTINUE); 1025 } 1026 1027 static int 1028 zio_free_bp_init(zio_t *zio) 1029 { 1030 blkptr_t *bp = zio->io_bp; 1031 1032 if (zio->io_child_type == ZIO_CHILD_LOGICAL) { 1033 if (BP_GET_DEDUP(bp)) 1034 zio->io_pipeline = ZIO_DDT_FREE_PIPELINE; 1035 } 1036 1037 return (ZIO_PIPELINE_CONTINUE); 1038 } 1039 1040 /* 1041 * ========================================================================== 1042 * Execute the I/O pipeline 1043 * ========================================================================== 1044 */ 1045 1046 static void 1047 zio_taskq_dispatch(zio_t *zio, enum zio_taskq_type q, boolean_t cutinline) 1048 { 1049 spa_t *spa = zio->io_spa; 1050 zio_type_t t = zio->io_type; 1051 int flags = TQ_SLEEP | (cutinline ? TQ_FRONT : 0); 1052 1053 /* 1054 * If we're a config writer or a probe, the normal issue and 1055 * interrupt threads may all be blocked waiting for the config lock. 1056 * In this case, select the otherwise-unused taskq for ZIO_TYPE_NULL. 1057 */ 1058 if (zio->io_flags & (ZIO_FLAG_CONFIG_WRITER | ZIO_FLAG_PROBE)) 1059 t = ZIO_TYPE_NULL; 1060 1061 /* 1062 * A similar issue exists for the L2ARC write thread until L2ARC 2.0. 1063 */ 1064 if (t == ZIO_TYPE_WRITE && zio->io_vd && zio->io_vd->vdev_aux) 1065 t = ZIO_TYPE_NULL; 1066 1067 /* 1068 * If this is a high priority I/O, then use the high priority taskq. 1069 */ 1070 if (zio->io_priority == ZIO_PRIORITY_NOW && 1071 spa->spa_zio_taskq[t][q + 1] != NULL) 1072 q++; 1073 1074 ASSERT3U(q, <, ZIO_TASKQ_TYPES); 1075 (void) taskq_dispatch(spa->spa_zio_taskq[t][q], 1076 (task_func_t *)zio_execute, zio, flags); 1077 } 1078 1079 static boolean_t 1080 zio_taskq_member(zio_t *zio, enum zio_taskq_type q) 1081 { 1082 kthread_t *executor = zio->io_executor; 1083 spa_t *spa = zio->io_spa; 1084 1085 for (zio_type_t t = 0; t < ZIO_TYPES; t++) 1086 if (taskq_member(spa->spa_zio_taskq[t][q], executor)) 1087 return (B_TRUE); 1088 1089 return (B_FALSE); 1090 } 1091 1092 static int 1093 zio_issue_async(zio_t *zio) 1094 { 1095 zio_taskq_dispatch(zio, ZIO_TASKQ_ISSUE, B_FALSE); 1096 1097 return (ZIO_PIPELINE_STOP); 1098 } 1099 1100 void 1101 zio_interrupt(zio_t *zio) 1102 { 1103 zio_taskq_dispatch(zio, ZIO_TASKQ_INTERRUPT, B_FALSE); 1104 } 1105 1106 /* 1107 * Execute the I/O pipeline until one of the following occurs: 1108 * (1) the I/O completes; (2) the pipeline stalls waiting for 1109 * dependent child I/Os; (3) the I/O issues, so we're waiting 1110 * for an I/O completion interrupt; (4) the I/O is delegated by 1111 * vdev-level caching or aggregation; (5) the I/O is deferred 1112 * due to vdev-level queueing; (6) the I/O is handed off to 1113 * another thread. In all cases, the pipeline stops whenever 1114 * there's no CPU work; it never burns a thread in cv_wait(). 1115 * 1116 * There's no locking on io_stage because there's no legitimate way 1117 * for multiple threads to be attempting to process the same I/O. 1118 */ 1119 static zio_pipe_stage_t *zio_pipeline[]; 1120 1121 void 1122 zio_execute(zio_t *zio) 1123 { 1124 zio->io_executor = curthread; 1125 1126 while (zio->io_stage < ZIO_STAGE_DONE) { 1127 enum zio_stage pipeline = zio->io_pipeline; 1128 enum zio_stage stage = zio->io_stage; 1129 int rv; 1130 1131 ASSERT(!MUTEX_HELD(&zio->io_lock)); 1132 ASSERT(ISP2(stage)); 1133 ASSERT(zio->io_stall == NULL); 1134 1135 do { 1136 stage <<= 1; 1137 } while ((stage & pipeline) == 0); 1138 1139 ASSERT(stage <= ZIO_STAGE_DONE); 1140 1141 /* 1142 * If we are in interrupt context and this pipeline stage 1143 * will grab a config lock that is held across I/O, 1144 * or may wait for an I/O that needs an interrupt thread 1145 * to complete, issue async to avoid deadlock. 1146 * 1147 * For VDEV_IO_START, we cut in line so that the io will 1148 * be sent to disk promptly. 1149 */ 1150 if ((stage & ZIO_BLOCKING_STAGES) && zio->io_vd == NULL && 1151 zio_taskq_member(zio, ZIO_TASKQ_INTERRUPT)) { 1152 boolean_t cut = (stage == ZIO_STAGE_VDEV_IO_START) ? 1153 zio_requeue_io_start_cut_in_line : B_FALSE; 1154 zio_taskq_dispatch(zio, ZIO_TASKQ_ISSUE, cut); 1155 return; 1156 } 1157 1158 zio->io_stage = stage; 1159 rv = zio_pipeline[highbit(stage) - 1](zio); 1160 1161 if (rv == ZIO_PIPELINE_STOP) 1162 return; 1163 1164 ASSERT(rv == ZIO_PIPELINE_CONTINUE); 1165 } 1166 } 1167 1168 /* 1169 * ========================================================================== 1170 * Initiate I/O, either sync or async 1171 * ========================================================================== 1172 */ 1173 int 1174 zio_wait(zio_t *zio) 1175 { 1176 int error; 1177 1178 ASSERT(zio->io_stage == ZIO_STAGE_OPEN); 1179 ASSERT(zio->io_executor == NULL); 1180 1181 zio->io_waiter = curthread; 1182 1183 zio_execute(zio); 1184 1185 mutex_enter(&zio->io_lock); 1186 while (zio->io_executor != NULL) 1187 cv_wait(&zio->io_cv, &zio->io_lock); 1188 mutex_exit(&zio->io_lock); 1189 1190 error = zio->io_error; 1191 zio_destroy(zio); 1192 1193 return (error); 1194 } 1195 1196 void 1197 zio_nowait(zio_t *zio) 1198 { 1199 ASSERT(zio->io_executor == NULL); 1200 1201 if (zio->io_child_type == ZIO_CHILD_LOGICAL && 1202 zio_unique_parent(zio) == NULL) { 1203 /* 1204 * This is a logical async I/O with no parent to wait for it. 1205 * We add it to the spa_async_root_zio "Godfather" I/O which 1206 * will ensure they complete prior to unloading the pool. 1207 */ 1208 spa_t *spa = zio->io_spa; 1209 1210 zio_add_child(spa->spa_async_zio_root, zio); 1211 } 1212 1213 zio_execute(zio); 1214 } 1215 1216 /* 1217 * ========================================================================== 1218 * Reexecute or suspend/resume failed I/O 1219 * ========================================================================== 1220 */ 1221 1222 static void 1223 zio_reexecute(zio_t *pio) 1224 { 1225 zio_t *cio, *cio_next; 1226 1227 ASSERT(pio->io_child_type == ZIO_CHILD_LOGICAL); 1228 ASSERT(pio->io_orig_stage == ZIO_STAGE_OPEN); 1229 ASSERT(pio->io_gang_leader == NULL); 1230 ASSERT(pio->io_gang_tree == NULL); 1231 1232 pio->io_flags = pio->io_orig_flags; 1233 pio->io_stage = pio->io_orig_stage; 1234 pio->io_pipeline = pio->io_orig_pipeline; 1235 pio->io_reexecute = 0; 1236 pio->io_error = 0; 1237 for (int w = 0; w < ZIO_WAIT_TYPES; w++) 1238 pio->io_state[w] = 0; 1239 for (int c = 0; c < ZIO_CHILD_TYPES; c++) 1240 pio->io_child_error[c] = 0; 1241 1242 if (IO_IS_ALLOCATING(pio)) 1243 BP_ZERO(pio->io_bp); 1244 1245 /* 1246 * As we reexecute pio's children, new children could be created. 1247 * New children go to the head of pio's io_child_list, however, 1248 * so we will (correctly) not reexecute them. The key is that 1249 * the remainder of pio's io_child_list, from 'cio_next' onward, 1250 * cannot be affected by any side effects of reexecuting 'cio'. 1251 */ 1252 for (cio = zio_walk_children(pio); cio != NULL; cio = cio_next) { 1253 cio_next = zio_walk_children(pio); 1254 mutex_enter(&pio->io_lock); 1255 for (int w = 0; w < ZIO_WAIT_TYPES; w++) 1256 pio->io_children[cio->io_child_type][w]++; 1257 mutex_exit(&pio->io_lock); 1258 zio_reexecute(cio); 1259 } 1260 1261 /* 1262 * Now that all children have been reexecuted, execute the parent. 1263 * We don't reexecute "The Godfather" I/O here as it's the 1264 * responsibility of the caller to wait on him. 1265 */ 1266 if (!(pio->io_flags & ZIO_FLAG_GODFATHER)) 1267 zio_execute(pio); 1268 } 1269 1270 void 1271 zio_suspend(spa_t *spa, zio_t *zio) 1272 { 1273 if (spa_get_failmode(spa) == ZIO_FAILURE_MODE_PANIC) 1274 fm_panic("Pool '%s' has encountered an uncorrectable I/O " 1275 "failure and the failure mode property for this pool " 1276 "is set to panic.", spa_name(spa)); 1277 1278 zfs_ereport_post(FM_EREPORT_ZFS_IO_FAILURE, spa, NULL, NULL, 0, 0); 1279 1280 mutex_enter(&spa->spa_suspend_lock); 1281 1282 if (spa->spa_suspend_zio_root == NULL) 1283 spa->spa_suspend_zio_root = zio_root(spa, NULL, NULL, 1284 ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE | 1285 ZIO_FLAG_GODFATHER); 1286 1287 spa->spa_suspended = B_TRUE; 1288 1289 if (zio != NULL) { 1290 ASSERT(!(zio->io_flags & ZIO_FLAG_GODFATHER)); 1291 ASSERT(zio != spa->spa_suspend_zio_root); 1292 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL); 1293 ASSERT(zio_unique_parent(zio) == NULL); 1294 ASSERT(zio->io_stage == ZIO_STAGE_DONE); 1295 zio_add_child(spa->spa_suspend_zio_root, zio); 1296 } 1297 1298 mutex_exit(&spa->spa_suspend_lock); 1299 } 1300 1301 int 1302 zio_resume(spa_t *spa) 1303 { 1304 zio_t *pio; 1305 1306 /* 1307 * Reexecute all previously suspended i/o. 1308 */ 1309 mutex_enter(&spa->spa_suspend_lock); 1310 spa->spa_suspended = B_FALSE; 1311 cv_broadcast(&spa->spa_suspend_cv); 1312 pio = spa->spa_suspend_zio_root; 1313 spa->spa_suspend_zio_root = NULL; 1314 mutex_exit(&spa->spa_suspend_lock); 1315 1316 if (pio == NULL) 1317 return (0); 1318 1319 zio_reexecute(pio); 1320 return (zio_wait(pio)); 1321 } 1322 1323 void 1324 zio_resume_wait(spa_t *spa) 1325 { 1326 mutex_enter(&spa->spa_suspend_lock); 1327 while (spa_suspended(spa)) 1328 cv_wait(&spa->spa_suspend_cv, &spa->spa_suspend_lock); 1329 mutex_exit(&spa->spa_suspend_lock); 1330 } 1331 1332 /* 1333 * ========================================================================== 1334 * Gang blocks. 1335 * 1336 * A gang block is a collection of small blocks that looks to the DMU 1337 * like one large block. When zio_dva_allocate() cannot find a block 1338 * of the requested size, due to either severe fragmentation or the pool 1339 * being nearly full, it calls zio_write_gang_block() to construct the 1340 * block from smaller fragments. 1341 * 1342 * A gang block consists of a gang header (zio_gbh_phys_t) and up to 1343 * three (SPA_GBH_NBLKPTRS) gang members. The gang header is just like 1344 * an indirect block: it's an array of block pointers. It consumes 1345 * only one sector and hence is allocatable regardless of fragmentation. 1346 * The gang header's bps point to its gang members, which hold the data. 1347 * 1348 * Gang blocks are self-checksumming, using the bp's <vdev, offset, txg> 1349 * as the verifier to ensure uniqueness of the SHA256 checksum. 1350 * Critically, the gang block bp's blk_cksum is the checksum of the data, 1351 * not the gang header. This ensures that data block signatures (needed for 1352 * deduplication) are independent of how the block is physically stored. 1353 * 1354 * Gang blocks can be nested: a gang member may itself be a gang block. 1355 * Thus every gang block is a tree in which root and all interior nodes are 1356 * gang headers, and the leaves are normal blocks that contain user data. 1357 * The root of the gang tree is called the gang leader. 1358 * 1359 * To perform any operation (read, rewrite, free, claim) on a gang block, 1360 * zio_gang_assemble() first assembles the gang tree (minus data leaves) 1361 * in the io_gang_tree field of the original logical i/o by recursively 1362 * reading the gang leader and all gang headers below it. This yields 1363 * an in-core tree containing the contents of every gang header and the 1364 * bps for every constituent of the gang block. 1365 * 1366 * With the gang tree now assembled, zio_gang_issue() just walks the gang tree 1367 * and invokes a callback on each bp. To free a gang block, zio_gang_issue() 1368 * calls zio_free_gang() -- a trivial wrapper around zio_free() -- for each bp. 1369 * zio_claim_gang() provides a similarly trivial wrapper for zio_claim(). 1370 * zio_read_gang() is a wrapper around zio_read() that omits reading gang 1371 * headers, since we already have those in io_gang_tree. zio_rewrite_gang() 1372 * performs a zio_rewrite() of the data or, for gang headers, a zio_rewrite() 1373 * of the gang header plus zio_checksum_compute() of the data to update the 1374 * gang header's blk_cksum as described above. 1375 * 1376 * The two-phase assemble/issue model solves the problem of partial failure -- 1377 * what if you'd freed part of a gang block but then couldn't read the 1378 * gang header for another part? Assembling the entire gang tree first 1379 * ensures that all the necessary gang header I/O has succeeded before 1380 * starting the actual work of free, claim, or write. Once the gang tree 1381 * is assembled, free and claim are in-memory operations that cannot fail. 1382 * 1383 * In the event that a gang write fails, zio_dva_unallocate() walks the 1384 * gang tree to immediately free (i.e. insert back into the space map) 1385 * everything we've allocated. This ensures that we don't get ENOSPC 1386 * errors during repeated suspend/resume cycles due to a flaky device. 1387 * 1388 * Gang rewrites only happen during sync-to-convergence. If we can't assemble 1389 * the gang tree, we won't modify the block, so we can safely defer the free 1390 * (knowing that the block is still intact). If we *can* assemble the gang 1391 * tree, then even if some of the rewrites fail, zio_dva_unallocate() will free 1392 * each constituent bp and we can allocate a new block on the next sync pass. 1393 * 1394 * In all cases, the gang tree allows complete recovery from partial failure. 1395 * ========================================================================== 1396 */ 1397 1398 static zio_t * 1399 zio_read_gang(zio_t *pio, blkptr_t *bp, zio_gang_node_t *gn, void *data) 1400 { 1401 if (gn != NULL) 1402 return (pio); 1403 1404 return (zio_read(pio, pio->io_spa, bp, data, BP_GET_PSIZE(bp), 1405 NULL, NULL, pio->io_priority, ZIO_GANG_CHILD_FLAGS(pio), 1406 &pio->io_bookmark)); 1407 } 1408 1409 zio_t * 1410 zio_rewrite_gang(zio_t *pio, blkptr_t *bp, zio_gang_node_t *gn, void *data) 1411 { 1412 zio_t *zio; 1413 1414 if (gn != NULL) { 1415 zio = zio_rewrite(pio, pio->io_spa, pio->io_txg, bp, 1416 gn->gn_gbh, SPA_GANGBLOCKSIZE, NULL, NULL, pio->io_priority, 1417 ZIO_GANG_CHILD_FLAGS(pio), &pio->io_bookmark); 1418 /* 1419 * As we rewrite each gang header, the pipeline will compute 1420 * a new gang block header checksum for it; but no one will 1421 * compute a new data checksum, so we do that here. The one 1422 * exception is the gang leader: the pipeline already computed 1423 * its data checksum because that stage precedes gang assembly. 1424 * (Presently, nothing actually uses interior data checksums; 1425 * this is just good hygiene.) 1426 */ 1427 if (gn != pio->io_gang_leader->io_gang_tree) { 1428 zio_checksum_compute(zio, BP_GET_CHECKSUM(bp), 1429 data, BP_GET_PSIZE(bp)); 1430 } 1431 /* 1432 * If we are here to damage data for testing purposes, 1433 * leave the GBH alone so that we can detect the damage. 1434 */ 1435 if (pio->io_gang_leader->io_flags & ZIO_FLAG_INDUCE_DAMAGE) 1436 zio->io_pipeline &= ~ZIO_VDEV_IO_STAGES; 1437 } else { 1438 zio = zio_rewrite(pio, pio->io_spa, pio->io_txg, bp, 1439 data, BP_GET_PSIZE(bp), NULL, NULL, pio->io_priority, 1440 ZIO_GANG_CHILD_FLAGS(pio), &pio->io_bookmark); 1441 } 1442 1443 return (zio); 1444 } 1445 1446 /* ARGSUSED */ 1447 zio_t * 1448 zio_free_gang(zio_t *pio, blkptr_t *bp, zio_gang_node_t *gn, void *data) 1449 { 1450 return (zio_free_sync(pio, pio->io_spa, pio->io_txg, bp, 1451 ZIO_GANG_CHILD_FLAGS(pio))); 1452 } 1453 1454 /* ARGSUSED */ 1455 zio_t * 1456 zio_claim_gang(zio_t *pio, blkptr_t *bp, zio_gang_node_t *gn, void *data) 1457 { 1458 return (zio_claim(pio, pio->io_spa, pio->io_txg, bp, 1459 NULL, NULL, ZIO_GANG_CHILD_FLAGS(pio))); 1460 } 1461 1462 static zio_gang_issue_func_t *zio_gang_issue_func[ZIO_TYPES] = { 1463 NULL, 1464 zio_read_gang, 1465 zio_rewrite_gang, 1466 zio_free_gang, 1467 zio_claim_gang, 1468 NULL 1469 }; 1470 1471 static void zio_gang_tree_assemble_done(zio_t *zio); 1472 1473 static zio_gang_node_t * 1474 zio_gang_node_alloc(zio_gang_node_t **gnpp) 1475 { 1476 zio_gang_node_t *gn; 1477 1478 ASSERT(*gnpp == NULL); 1479 1480 gn = kmem_zalloc(sizeof (*gn), KM_SLEEP); 1481 gn->gn_gbh = zio_buf_alloc(SPA_GANGBLOCKSIZE); 1482 *gnpp = gn; 1483 1484 return (gn); 1485 } 1486 1487 static void 1488 zio_gang_node_free(zio_gang_node_t **gnpp) 1489 { 1490 zio_gang_node_t *gn = *gnpp; 1491 1492 for (int g = 0; g < SPA_GBH_NBLKPTRS; g++) 1493 ASSERT(gn->gn_child[g] == NULL); 1494 1495 zio_buf_free(gn->gn_gbh, SPA_GANGBLOCKSIZE); 1496 kmem_free(gn, sizeof (*gn)); 1497 *gnpp = NULL; 1498 } 1499 1500 static void 1501 zio_gang_tree_free(zio_gang_node_t **gnpp) 1502 { 1503 zio_gang_node_t *gn = *gnpp; 1504 1505 if (gn == NULL) 1506 return; 1507 1508 for (int g = 0; g < SPA_GBH_NBLKPTRS; g++) 1509 zio_gang_tree_free(&gn->gn_child[g]); 1510 1511 zio_gang_node_free(gnpp); 1512 } 1513 1514 static void 1515 zio_gang_tree_assemble(zio_t *gio, blkptr_t *bp, zio_gang_node_t **gnpp) 1516 { 1517 zio_gang_node_t *gn = zio_gang_node_alloc(gnpp); 1518 1519 ASSERT(gio->io_gang_leader == gio); 1520 ASSERT(BP_IS_GANG(bp)); 1521 1522 zio_nowait(zio_read(gio, gio->io_spa, bp, gn->gn_gbh, 1523 SPA_GANGBLOCKSIZE, zio_gang_tree_assemble_done, gn, 1524 gio->io_priority, ZIO_GANG_CHILD_FLAGS(gio), &gio->io_bookmark)); 1525 } 1526 1527 static void 1528 zio_gang_tree_assemble_done(zio_t *zio) 1529 { 1530 zio_t *gio = zio->io_gang_leader; 1531 zio_gang_node_t *gn = zio->io_private; 1532 blkptr_t *bp = zio->io_bp; 1533 1534 ASSERT(gio == zio_unique_parent(zio)); 1535 ASSERT(zio->io_child_count == 0); 1536 1537 if (zio->io_error) 1538 return; 1539 1540 if (BP_SHOULD_BYTESWAP(bp)) 1541 byteswap_uint64_array(zio->io_data, zio->io_size); 1542 1543 ASSERT(zio->io_data == gn->gn_gbh); 1544 ASSERT(zio->io_size == SPA_GANGBLOCKSIZE); 1545 ASSERT(gn->gn_gbh->zg_tail.zec_magic == ZEC_MAGIC); 1546 1547 for (int g = 0; g < SPA_GBH_NBLKPTRS; g++) { 1548 blkptr_t *gbp = &gn->gn_gbh->zg_blkptr[g]; 1549 if (!BP_IS_GANG(gbp)) 1550 continue; 1551 zio_gang_tree_assemble(gio, gbp, &gn->gn_child[g]); 1552 } 1553 } 1554 1555 static void 1556 zio_gang_tree_issue(zio_t *pio, zio_gang_node_t *gn, blkptr_t *bp, void *data) 1557 { 1558 zio_t *gio = pio->io_gang_leader; 1559 zio_t *zio; 1560 1561 ASSERT(BP_IS_GANG(bp) == !!gn); 1562 ASSERT(BP_GET_CHECKSUM(bp) == BP_GET_CHECKSUM(gio->io_bp)); 1563 ASSERT(BP_GET_LSIZE(bp) == BP_GET_PSIZE(bp) || gn == gio->io_gang_tree); 1564 1565 /* 1566 * If you're a gang header, your data is in gn->gn_gbh. 1567 * If you're a gang member, your data is in 'data' and gn == NULL. 1568 */ 1569 zio = zio_gang_issue_func[gio->io_type](pio, bp, gn, data); 1570 1571 if (gn != NULL) { 1572 ASSERT(gn->gn_gbh->zg_tail.zec_magic == ZEC_MAGIC); 1573 1574 for (int g = 0; g < SPA_GBH_NBLKPTRS; g++) { 1575 blkptr_t *gbp = &gn->gn_gbh->zg_blkptr[g]; 1576 if (BP_IS_HOLE(gbp)) 1577 continue; 1578 zio_gang_tree_issue(zio, gn->gn_child[g], gbp, data); 1579 data = (char *)data + BP_GET_PSIZE(gbp); 1580 } 1581 } 1582 1583 if (gn == gio->io_gang_tree) 1584 ASSERT3P((char *)gio->io_data + gio->io_size, ==, data); 1585 1586 if (zio != pio) 1587 zio_nowait(zio); 1588 } 1589 1590 static int 1591 zio_gang_assemble(zio_t *zio) 1592 { 1593 blkptr_t *bp = zio->io_bp; 1594 1595 ASSERT(BP_IS_GANG(bp) && zio->io_gang_leader == NULL); 1596 ASSERT(zio->io_child_type > ZIO_CHILD_GANG); 1597 1598 zio->io_gang_leader = zio; 1599 1600 zio_gang_tree_assemble(zio, bp, &zio->io_gang_tree); 1601 1602 return (ZIO_PIPELINE_CONTINUE); 1603 } 1604 1605 static int 1606 zio_gang_issue(zio_t *zio) 1607 { 1608 blkptr_t *bp = zio->io_bp; 1609 1610 if (zio_wait_for_children(zio, ZIO_CHILD_GANG, ZIO_WAIT_DONE)) 1611 return (ZIO_PIPELINE_STOP); 1612 1613 ASSERT(BP_IS_GANG(bp) && zio->io_gang_leader == zio); 1614 ASSERT(zio->io_child_type > ZIO_CHILD_GANG); 1615 1616 if (zio->io_child_error[ZIO_CHILD_GANG] == 0) 1617 zio_gang_tree_issue(zio, zio->io_gang_tree, bp, zio->io_data); 1618 else 1619 zio_gang_tree_free(&zio->io_gang_tree); 1620 1621 zio->io_pipeline = ZIO_INTERLOCK_PIPELINE; 1622 1623 return (ZIO_PIPELINE_CONTINUE); 1624 } 1625 1626 static void 1627 zio_write_gang_member_ready(zio_t *zio) 1628 { 1629 zio_t *pio = zio_unique_parent(zio); 1630 zio_t *gio = zio->io_gang_leader; 1631 dva_t *cdva = zio->io_bp->blk_dva; 1632 dva_t *pdva = pio->io_bp->blk_dva; 1633 uint64_t asize; 1634 1635 if (BP_IS_HOLE(zio->io_bp)) 1636 return; 1637 1638 ASSERT(BP_IS_HOLE(&zio->io_bp_orig)); 1639 1640 ASSERT(zio->io_child_type == ZIO_CHILD_GANG); 1641 ASSERT3U(zio->io_prop.zp_copies, ==, gio->io_prop.zp_copies); 1642 ASSERT3U(zio->io_prop.zp_copies, <=, BP_GET_NDVAS(zio->io_bp)); 1643 ASSERT3U(pio->io_prop.zp_copies, <=, BP_GET_NDVAS(pio->io_bp)); 1644 ASSERT3U(BP_GET_NDVAS(zio->io_bp), <=, BP_GET_NDVAS(pio->io_bp)); 1645 1646 mutex_enter(&pio->io_lock); 1647 for (int d = 0; d < BP_GET_NDVAS(zio->io_bp); d++) { 1648 ASSERT(DVA_GET_GANG(&pdva[d])); 1649 asize = DVA_GET_ASIZE(&pdva[d]); 1650 asize += DVA_GET_ASIZE(&cdva[d]); 1651 DVA_SET_ASIZE(&pdva[d], asize); 1652 } 1653 mutex_exit(&pio->io_lock); 1654 } 1655 1656 static int 1657 zio_write_gang_block(zio_t *pio) 1658 { 1659 spa_t *spa = pio->io_spa; 1660 blkptr_t *bp = pio->io_bp; 1661 zio_t *gio = pio->io_gang_leader; 1662 zio_t *zio; 1663 zio_gang_node_t *gn, **gnpp; 1664 zio_gbh_phys_t *gbh; 1665 uint64_t txg = pio->io_txg; 1666 uint64_t resid = pio->io_size; 1667 uint64_t lsize; 1668 int copies = gio->io_prop.zp_copies; 1669 int gbh_copies = MIN(copies + 1, spa_max_replication(spa)); 1670 zio_prop_t zp; 1671 int error; 1672 1673 error = metaslab_alloc(spa, spa_normal_class(spa), SPA_GANGBLOCKSIZE, 1674 bp, gbh_copies, txg, pio == gio ? NULL : gio->io_bp, 1675 METASLAB_HINTBP_FAVOR | METASLAB_GANG_HEADER); 1676 if (error) { 1677 pio->io_error = error; 1678 return (ZIO_PIPELINE_CONTINUE); 1679 } 1680 1681 if (pio == gio) { 1682 gnpp = &gio->io_gang_tree; 1683 } else { 1684 gnpp = pio->io_private; 1685 ASSERT(pio->io_ready == zio_write_gang_member_ready); 1686 } 1687 1688 gn = zio_gang_node_alloc(gnpp); 1689 gbh = gn->gn_gbh; 1690 bzero(gbh, SPA_GANGBLOCKSIZE); 1691 1692 /* 1693 * Create the gang header. 1694 */ 1695 zio = zio_rewrite(pio, spa, txg, bp, gbh, SPA_GANGBLOCKSIZE, NULL, NULL, 1696 pio->io_priority, ZIO_GANG_CHILD_FLAGS(pio), &pio->io_bookmark); 1697 1698 /* 1699 * Create and nowait the gang children. 1700 */ 1701 for (int g = 0; resid != 0; resid -= lsize, g++) { 1702 lsize = P2ROUNDUP(resid / (SPA_GBH_NBLKPTRS - g), 1703 SPA_MINBLOCKSIZE); 1704 ASSERT(lsize >= SPA_MINBLOCKSIZE && lsize <= resid); 1705 1706 zp.zp_checksum = gio->io_prop.zp_checksum; 1707 zp.zp_compress = ZIO_COMPRESS_OFF; 1708 zp.zp_type = DMU_OT_NONE; 1709 zp.zp_level = 0; 1710 zp.zp_copies = gio->io_prop.zp_copies; 1711 zp.zp_dedup = 0; 1712 zp.zp_dedup_verify = 0; 1713 1714 zio_nowait(zio_write(zio, spa, txg, &gbh->zg_blkptr[g], 1715 (char *)pio->io_data + (pio->io_size - resid), lsize, &zp, 1716 zio_write_gang_member_ready, NULL, &gn->gn_child[g], 1717 pio->io_priority, ZIO_GANG_CHILD_FLAGS(pio), 1718 &pio->io_bookmark)); 1719 } 1720 1721 /* 1722 * Set pio's pipeline to just wait for zio to finish. 1723 */ 1724 pio->io_pipeline = ZIO_INTERLOCK_PIPELINE; 1725 1726 zio_nowait(zio); 1727 1728 return (ZIO_PIPELINE_CONTINUE); 1729 } 1730 1731 /* 1732 * ========================================================================== 1733 * Dedup 1734 * ========================================================================== 1735 */ 1736 static void 1737 zio_ddt_child_read_done(zio_t *zio) 1738 { 1739 blkptr_t *bp = zio->io_bp; 1740 ddt_entry_t *dde = zio->io_private; 1741 ddt_phys_t *ddp; 1742 zio_t *pio = zio_unique_parent(zio); 1743 1744 mutex_enter(&pio->io_lock); 1745 ddp = ddt_phys_select(dde, bp); 1746 if (zio->io_error == 0) 1747 ddt_phys_clear(ddp); /* this ddp doesn't need repair */ 1748 if (zio->io_error == 0 && dde->dde_repair_data == NULL) 1749 dde->dde_repair_data = zio->io_data; 1750 else 1751 zio_buf_free(zio->io_data, zio->io_size); 1752 mutex_exit(&pio->io_lock); 1753 } 1754 1755 static int 1756 zio_ddt_read_start(zio_t *zio) 1757 { 1758 blkptr_t *bp = zio->io_bp; 1759 1760 ASSERT(BP_GET_DEDUP(bp)); 1761 ASSERT(BP_GET_PSIZE(bp) == zio->io_size); 1762 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL); 1763 1764 if (zio->io_child_error[ZIO_CHILD_DDT]) { 1765 ddt_t *ddt = ddt_select(zio->io_spa, bp); 1766 ddt_entry_t *dde = ddt_repair_start(ddt, bp); 1767 ddt_phys_t *ddp = dde->dde_phys; 1768 ddt_phys_t *ddp_self = ddt_phys_select(dde, bp); 1769 blkptr_t blk; 1770 1771 ASSERT(zio->io_vsd == NULL); 1772 zio->io_vsd = dde; 1773 1774 if (ddp_self == NULL) 1775 return (ZIO_PIPELINE_CONTINUE); 1776 1777 for (int p = 0; p < DDT_PHYS_TYPES; p++, ddp++) { 1778 if (ddp->ddp_phys_birth == 0 || ddp == ddp_self) 1779 continue; 1780 ddt_bp_create(ddt->ddt_checksum, &dde->dde_key, ddp, 1781 &blk); 1782 zio_nowait(zio_read(zio, zio->io_spa, &blk, 1783 zio_buf_alloc(zio->io_size), zio->io_size, 1784 zio_ddt_child_read_done, dde, zio->io_priority, 1785 ZIO_DDT_CHILD_FLAGS(zio) | ZIO_FLAG_DONT_PROPAGATE, 1786 &zio->io_bookmark)); 1787 } 1788 return (ZIO_PIPELINE_CONTINUE); 1789 } 1790 1791 zio_nowait(zio_read(zio, zio->io_spa, bp, 1792 zio->io_data, zio->io_size, NULL, NULL, zio->io_priority, 1793 ZIO_DDT_CHILD_FLAGS(zio), &zio->io_bookmark)); 1794 1795 return (ZIO_PIPELINE_CONTINUE); 1796 } 1797 1798 static int 1799 zio_ddt_read_done(zio_t *zio) 1800 { 1801 blkptr_t *bp = zio->io_bp; 1802 1803 if (zio_wait_for_children(zio, ZIO_CHILD_DDT, ZIO_WAIT_DONE)) 1804 return (ZIO_PIPELINE_STOP); 1805 1806 ASSERT(BP_GET_DEDUP(bp)); 1807 ASSERT(BP_GET_PSIZE(bp) == zio->io_size); 1808 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL); 1809 1810 if (zio->io_child_error[ZIO_CHILD_DDT]) { 1811 ddt_t *ddt = ddt_select(zio->io_spa, bp); 1812 ddt_entry_t *dde = zio->io_vsd; 1813 if (ddt == NULL) { 1814 ASSERT(spa_load_state(zio->io_spa) != SPA_LOAD_NONE); 1815 return (ZIO_PIPELINE_CONTINUE); 1816 } 1817 if (dde == NULL) { 1818 zio->io_stage = ZIO_STAGE_DDT_READ_START >> 1; 1819 zio_taskq_dispatch(zio, ZIO_TASKQ_ISSUE, B_FALSE); 1820 return (ZIO_PIPELINE_STOP); 1821 } 1822 if (dde->dde_repair_data != NULL) { 1823 bcopy(dde->dde_repair_data, zio->io_data, zio->io_size); 1824 zio->io_child_error[ZIO_CHILD_DDT] = 0; 1825 } 1826 ddt_repair_done(ddt, dde); 1827 zio->io_vsd = NULL; 1828 } 1829 1830 ASSERT(zio->io_vsd == NULL); 1831 1832 return (ZIO_PIPELINE_CONTINUE); 1833 } 1834 1835 static boolean_t 1836 zio_ddt_collision(zio_t *zio, ddt_t *ddt, ddt_entry_t *dde) 1837 { 1838 spa_t *spa = zio->io_spa; 1839 1840 /* 1841 * Note: we compare the original data, not the transformed data, 1842 * because when zio->io_bp is an override bp, we will not have 1843 * pushed the I/O transforms. That's an important optimization 1844 * because otherwise we'd compress/encrypt all dmu_sync() data twice. 1845 */ 1846 for (int p = DDT_PHYS_SINGLE; p <= DDT_PHYS_TRIPLE; p++) { 1847 zio_t *lio = dde->dde_lead_zio[p]; 1848 1849 if (lio != NULL) { 1850 return (lio->io_orig_size != zio->io_orig_size || 1851 bcmp(zio->io_orig_data, lio->io_orig_data, 1852 zio->io_orig_size) != 0); 1853 } 1854 } 1855 1856 for (int p = DDT_PHYS_SINGLE; p <= DDT_PHYS_TRIPLE; p++) { 1857 ddt_phys_t *ddp = &dde->dde_phys[p]; 1858 1859 if (ddp->ddp_phys_birth != 0) { 1860 arc_buf_t *abuf = NULL; 1861 uint32_t aflags = ARC_WAIT; 1862 blkptr_t blk = *zio->io_bp; 1863 int error; 1864 1865 ddt_bp_fill(ddp, &blk, ddp->ddp_phys_birth); 1866 1867 ddt_exit(ddt); 1868 1869 error = arc_read_nolock(NULL, spa, &blk, 1870 arc_getbuf_func, &abuf, ZIO_PRIORITY_SYNC_READ, 1871 ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE, 1872 &aflags, &zio->io_bookmark); 1873 1874 if (error == 0) { 1875 if (arc_buf_size(abuf) != zio->io_orig_size || 1876 bcmp(abuf->b_data, zio->io_orig_data, 1877 zio->io_orig_size) != 0) 1878 error = EEXIST; 1879 VERIFY(arc_buf_remove_ref(abuf, &abuf) == 1); 1880 } 1881 1882 ddt_enter(ddt); 1883 return (error != 0); 1884 } 1885 } 1886 1887 return (B_FALSE); 1888 } 1889 1890 static void 1891 zio_ddt_child_write_ready(zio_t *zio) 1892 { 1893 int p = zio->io_prop.zp_copies; 1894 ddt_t *ddt = ddt_select(zio->io_spa, zio->io_bp); 1895 ddt_entry_t *dde = zio->io_private; 1896 ddt_phys_t *ddp = &dde->dde_phys[p]; 1897 zio_t *pio; 1898 1899 if (zio->io_error) 1900 return; 1901 1902 ddt_enter(ddt); 1903 1904 ASSERT(dde->dde_lead_zio[p] == zio); 1905 1906 ddt_phys_fill(ddp, zio->io_bp); 1907 1908 while ((pio = zio_walk_parents(zio)) != NULL) 1909 ddt_bp_fill(ddp, pio->io_bp, zio->io_txg); 1910 1911 ddt_exit(ddt); 1912 } 1913 1914 static void 1915 zio_ddt_child_write_done(zio_t *zio) 1916 { 1917 int p = zio->io_prop.zp_copies; 1918 ddt_t *ddt = ddt_select(zio->io_spa, zio->io_bp); 1919 ddt_entry_t *dde = zio->io_private; 1920 ddt_phys_t *ddp = &dde->dde_phys[p]; 1921 1922 ddt_enter(ddt); 1923 1924 ASSERT(ddp->ddp_refcnt == 0); 1925 ASSERT(dde->dde_lead_zio[p] == zio); 1926 dde->dde_lead_zio[p] = NULL; 1927 1928 if (zio->io_error == 0) { 1929 while (zio_walk_parents(zio) != NULL) 1930 ddt_phys_addref(ddp); 1931 } else { 1932 ddt_phys_clear(ddp); 1933 } 1934 1935 ddt_exit(ddt); 1936 } 1937 1938 static void 1939 zio_ddt_ditto_write_done(zio_t *zio) 1940 { 1941 int p = DDT_PHYS_DITTO; 1942 zio_prop_t *zp = &zio->io_prop; 1943 blkptr_t *bp = zio->io_bp; 1944 ddt_t *ddt = ddt_select(zio->io_spa, bp); 1945 ddt_entry_t *dde = zio->io_private; 1946 ddt_phys_t *ddp = &dde->dde_phys[p]; 1947 ddt_key_t *ddk = &dde->dde_key; 1948 1949 ddt_enter(ddt); 1950 1951 ASSERT(ddp->ddp_refcnt == 0); 1952 ASSERT(dde->dde_lead_zio[p] == zio); 1953 dde->dde_lead_zio[p] = NULL; 1954 1955 if (zio->io_error == 0) { 1956 ASSERT(ZIO_CHECKSUM_EQUAL(bp->blk_cksum, ddk->ddk_cksum)); 1957 ASSERT(zp->zp_copies < SPA_DVAS_PER_BP); 1958 ASSERT(zp->zp_copies == BP_GET_NDVAS(bp) - BP_IS_GANG(bp)); 1959 if (ddp->ddp_phys_birth != 0) 1960 ddt_phys_free(ddt, ddk, ddp, zio->io_txg); 1961 ddt_phys_fill(ddp, bp); 1962 } 1963 1964 ddt_exit(ddt); 1965 } 1966 1967 static int 1968 zio_ddt_write(zio_t *zio) 1969 { 1970 spa_t *spa = zio->io_spa; 1971 blkptr_t *bp = zio->io_bp; 1972 uint64_t txg = zio->io_txg; 1973 zio_prop_t *zp = &zio->io_prop; 1974 int p = zp->zp_copies; 1975 int ditto_copies; 1976 zio_t *cio = NULL; 1977 zio_t *dio = NULL; 1978 ddt_t *ddt = ddt_select(spa, bp); 1979 ddt_entry_t *dde; 1980 ddt_phys_t *ddp; 1981 1982 ASSERT(BP_GET_DEDUP(bp)); 1983 ASSERT(BP_GET_CHECKSUM(bp) == zp->zp_checksum); 1984 ASSERT(BP_IS_HOLE(bp) || zio->io_bp_override); 1985 1986 ddt_enter(ddt); 1987 dde = ddt_lookup(ddt, bp, B_TRUE); 1988 ddp = &dde->dde_phys[p]; 1989 1990 if (zp->zp_dedup_verify && zio_ddt_collision(zio, ddt, dde)) { 1991 /* 1992 * If we're using a weak checksum, upgrade to a strong checksum 1993 * and try again. If we're already using a strong checksum, 1994 * we can't resolve it, so just convert to an ordinary write. 1995 * (And automatically e-mail a paper to Nature?) 1996 */ 1997 if (!zio_checksum_table[zp->zp_checksum].ci_dedup) { 1998 zp->zp_checksum = spa_dedup_checksum(spa); 1999 zio_pop_transforms(zio); 2000 zio->io_stage = ZIO_STAGE_OPEN; 2001 BP_ZERO(bp); 2002 } else { 2003 zp->zp_dedup = 0; 2004 } 2005 zio->io_pipeline = ZIO_WRITE_PIPELINE; 2006 ddt_exit(ddt); 2007 return (ZIO_PIPELINE_CONTINUE); 2008 } 2009 2010 ditto_copies = ddt_ditto_copies_needed(ddt, dde, ddp); 2011 ASSERT(ditto_copies < SPA_DVAS_PER_BP); 2012 2013 if (ditto_copies > ddt_ditto_copies_present(dde) && 2014 dde->dde_lead_zio[DDT_PHYS_DITTO] == NULL) { 2015 zio_prop_t czp = *zp; 2016 2017 czp.zp_copies = ditto_copies; 2018 2019 /* 2020 * If we arrived here with an override bp, we won't have run 2021 * the transform stack, so we won't have the data we need to 2022 * generate a child i/o. So, toss the override bp and restart. 2023 * This is safe, because using the override bp is just an 2024 * optimization; and it's rare, so the cost doesn't matter. 2025 */ 2026 if (zio->io_bp_override) { 2027 zio_pop_transforms(zio); 2028 zio->io_stage = ZIO_STAGE_OPEN; 2029 zio->io_pipeline = ZIO_WRITE_PIPELINE; 2030 zio->io_bp_override = NULL; 2031 BP_ZERO(bp); 2032 ddt_exit(ddt); 2033 return (ZIO_PIPELINE_CONTINUE); 2034 } 2035 2036 dio = zio_write(zio, spa, txg, bp, zio->io_orig_data, 2037 zio->io_orig_size, &czp, NULL, 2038 zio_ddt_ditto_write_done, dde, zio->io_priority, 2039 ZIO_DDT_CHILD_FLAGS(zio), &zio->io_bookmark); 2040 2041 zio_push_transform(dio, zio->io_data, zio->io_size, 0, NULL); 2042 dde->dde_lead_zio[DDT_PHYS_DITTO] = dio; 2043 } 2044 2045 if (ddp->ddp_phys_birth != 0 || dde->dde_lead_zio[p] != NULL) { 2046 if (ddp->ddp_phys_birth != 0) 2047 ddt_bp_fill(ddp, bp, txg); 2048 if (dde->dde_lead_zio[p] != NULL) 2049 zio_add_child(zio, dde->dde_lead_zio[p]); 2050 else 2051 ddt_phys_addref(ddp); 2052 } else if (zio->io_bp_override) { 2053 ASSERT(bp->blk_birth == txg); 2054 ASSERT(BP_EQUAL(bp, zio->io_bp_override)); 2055 ddt_phys_fill(ddp, bp); 2056 ddt_phys_addref(ddp); 2057 } else { 2058 cio = zio_write(zio, spa, txg, bp, zio->io_orig_data, 2059 zio->io_orig_size, zp, zio_ddt_child_write_ready, 2060 zio_ddt_child_write_done, dde, zio->io_priority, 2061 ZIO_DDT_CHILD_FLAGS(zio), &zio->io_bookmark); 2062 2063 zio_push_transform(cio, zio->io_data, zio->io_size, 0, NULL); 2064 dde->dde_lead_zio[p] = cio; 2065 } 2066 2067 ddt_exit(ddt); 2068 2069 if (cio) 2070 zio_nowait(cio); 2071 if (dio) 2072 zio_nowait(dio); 2073 2074 return (ZIO_PIPELINE_CONTINUE); 2075 } 2076 2077 ddt_entry_t *freedde; /* for debugging */ 2078 2079 static int 2080 zio_ddt_free(zio_t *zio) 2081 { 2082 spa_t *spa = zio->io_spa; 2083 blkptr_t *bp = zio->io_bp; 2084 ddt_t *ddt = ddt_select(spa, bp); 2085 ddt_entry_t *dde; 2086 ddt_phys_t *ddp; 2087 2088 ASSERT(BP_GET_DEDUP(bp)); 2089 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL); 2090 2091 ddt_enter(ddt); 2092 freedde = dde = ddt_lookup(ddt, bp, B_TRUE); 2093 ddp = ddt_phys_select(dde, bp); 2094 ddt_phys_decref(ddp); 2095 ddt_exit(ddt); 2096 2097 return (ZIO_PIPELINE_CONTINUE); 2098 } 2099 2100 /* 2101 * ========================================================================== 2102 * Allocate and free blocks 2103 * ========================================================================== 2104 */ 2105 static int 2106 zio_dva_allocate(zio_t *zio) 2107 { 2108 spa_t *spa = zio->io_spa; 2109 metaslab_class_t *mc = spa_normal_class(spa); 2110 blkptr_t *bp = zio->io_bp; 2111 int error; 2112 2113 if (zio->io_gang_leader == NULL) { 2114 ASSERT(zio->io_child_type > ZIO_CHILD_GANG); 2115 zio->io_gang_leader = zio; 2116 } 2117 2118 ASSERT(BP_IS_HOLE(bp)); 2119 ASSERT3U(BP_GET_NDVAS(bp), ==, 0); 2120 ASSERT3U(zio->io_prop.zp_copies, >, 0); 2121 ASSERT3U(zio->io_prop.zp_copies, <=, spa_max_replication(spa)); 2122 ASSERT3U(zio->io_size, ==, BP_GET_PSIZE(bp)); 2123 2124 error = metaslab_alloc(spa, mc, zio->io_size, bp, 2125 zio->io_prop.zp_copies, zio->io_txg, NULL, 0); 2126 2127 if (error) { 2128 if (error == ENOSPC && zio->io_size > SPA_MINBLOCKSIZE) 2129 return (zio_write_gang_block(zio)); 2130 zio->io_error = error; 2131 } 2132 2133 return (ZIO_PIPELINE_CONTINUE); 2134 } 2135 2136 static int 2137 zio_dva_free(zio_t *zio) 2138 { 2139 metaslab_free(zio->io_spa, zio->io_bp, zio->io_txg, B_FALSE); 2140 2141 return (ZIO_PIPELINE_CONTINUE); 2142 } 2143 2144 static int 2145 zio_dva_claim(zio_t *zio) 2146 { 2147 int error; 2148 2149 error = metaslab_claim(zio->io_spa, zio->io_bp, zio->io_txg); 2150 if (error) 2151 zio->io_error = error; 2152 2153 return (ZIO_PIPELINE_CONTINUE); 2154 } 2155 2156 /* 2157 * Undo an allocation. This is used by zio_done() when an I/O fails 2158 * and we want to give back the block we just allocated. 2159 * This handles both normal blocks and gang blocks. 2160 */ 2161 static void 2162 zio_dva_unallocate(zio_t *zio, zio_gang_node_t *gn, blkptr_t *bp) 2163 { 2164 ASSERT(bp->blk_birth == zio->io_txg || BP_IS_HOLE(bp)); 2165 ASSERT(zio->io_bp_override == NULL); 2166 2167 if (!BP_IS_HOLE(bp)) 2168 metaslab_free(zio->io_spa, bp, bp->blk_birth, B_TRUE); 2169 2170 if (gn != NULL) { 2171 for (int g = 0; g < SPA_GBH_NBLKPTRS; g++) { 2172 zio_dva_unallocate(zio, gn->gn_child[g], 2173 &gn->gn_gbh->zg_blkptr[g]); 2174 } 2175 } 2176 } 2177 2178 /* 2179 * Try to allocate an intent log block. Return 0 on success, errno on failure. 2180 */ 2181 int 2182 zio_alloc_zil(spa_t *spa, uint64_t txg, blkptr_t *new_bp, blkptr_t *old_bp, 2183 uint64_t size, boolean_t use_slog) 2184 { 2185 int error = 1; 2186 2187 ASSERT(txg > spa_syncing_txg(spa)); 2188 2189 if (use_slog) 2190 error = metaslab_alloc(spa, spa_log_class(spa), size, 2191 new_bp, 1, txg, old_bp, METASLAB_HINTBP_AVOID); 2192 2193 if (error) 2194 error = metaslab_alloc(spa, spa_normal_class(spa), size, 2195 new_bp, 1, txg, old_bp, METASLAB_HINTBP_AVOID); 2196 2197 if (error == 0) { 2198 BP_SET_LSIZE(new_bp, size); 2199 BP_SET_PSIZE(new_bp, size); 2200 BP_SET_COMPRESS(new_bp, ZIO_COMPRESS_OFF); 2201 BP_SET_CHECKSUM(new_bp, 2202 spa_version(spa) >= SPA_VERSION_SLIM_ZIL 2203 ? ZIO_CHECKSUM_ZILOG2 : ZIO_CHECKSUM_ZILOG); 2204 BP_SET_TYPE(new_bp, DMU_OT_INTENT_LOG); 2205 BP_SET_LEVEL(new_bp, 0); 2206 BP_SET_DEDUP(new_bp, 0); 2207 BP_SET_BYTEORDER(new_bp, ZFS_HOST_BYTEORDER); 2208 } 2209 2210 return (error); 2211 } 2212 2213 /* 2214 * Free an intent log block. 2215 */ 2216 void 2217 zio_free_zil(spa_t *spa, uint64_t txg, blkptr_t *bp) 2218 { 2219 ASSERT(BP_GET_TYPE(bp) == DMU_OT_INTENT_LOG); 2220 ASSERT(!BP_IS_GANG(bp)); 2221 2222 zio_free(spa, txg, bp); 2223 } 2224 2225 /* 2226 * ========================================================================== 2227 * Read and write to physical devices 2228 * ========================================================================== 2229 */ 2230 static int 2231 zio_vdev_io_start(zio_t *zio) 2232 { 2233 vdev_t *vd = zio->io_vd; 2234 uint64_t align; 2235 spa_t *spa = zio->io_spa; 2236 2237 ASSERT(zio->io_error == 0); 2238 ASSERT(zio->io_child_error[ZIO_CHILD_VDEV] == 0); 2239 2240 if (vd == NULL) { 2241 if (!(zio->io_flags & ZIO_FLAG_CONFIG_WRITER)) 2242 spa_config_enter(spa, SCL_ZIO, zio, RW_READER); 2243 2244 /* 2245 * The mirror_ops handle multiple DVAs in a single BP. 2246 */ 2247 return (vdev_mirror_ops.vdev_op_io_start(zio)); 2248 } 2249 2250 /* 2251 * We keep track of time-sensitive I/Os so that the scan thread 2252 * can quickly react to certain workloads. In particular, we care 2253 * about non-scrubbing, top-level reads and writes with the following 2254 * characteristics: 2255 * - synchronous writes of user data to non-slog devices 2256 * - any reads of user data 2257 * When these conditions are met, adjust the timestamp of spa_last_io 2258 * which allows the scan thread to adjust its workload accordingly. 2259 */ 2260 if (!(zio->io_flags & ZIO_FLAG_SCAN_THREAD) && zio->io_bp != NULL && 2261 vd == vd->vdev_top && !vd->vdev_islog && 2262 zio->io_bookmark.zb_objset != DMU_META_OBJSET && 2263 zio->io_txg != spa_syncing_txg(spa)) { 2264 uint64_t old = spa->spa_last_io; 2265 uint64_t new = ddi_get_lbolt64(); 2266 if (old != new) 2267 (void) atomic_cas_64(&spa->spa_last_io, old, new); 2268 } 2269 2270 align = 1ULL << vd->vdev_top->vdev_ashift; 2271 2272 if (P2PHASE(zio->io_size, align) != 0) { 2273 uint64_t asize = P2ROUNDUP(zio->io_size, align); 2274 char *abuf = zio_buf_alloc(asize); 2275 ASSERT(vd == vd->vdev_top); 2276 if (zio->io_type == ZIO_TYPE_WRITE) { 2277 bcopy(zio->io_data, abuf, zio->io_size); 2278 bzero(abuf + zio->io_size, asize - zio->io_size); 2279 } 2280 zio_push_transform(zio, abuf, asize, asize, zio_subblock); 2281 } 2282 2283 ASSERT(P2PHASE(zio->io_offset, align) == 0); 2284 ASSERT(P2PHASE(zio->io_size, align) == 0); 2285 ASSERT(zio->io_type != ZIO_TYPE_WRITE || spa_writeable(spa)); 2286 2287 /* 2288 * If this is a repair I/O, and there's no self-healing involved -- 2289 * that is, we're just resilvering what we expect to resilver -- 2290 * then don't do the I/O unless zio's txg is actually in vd's DTL. 2291 * This prevents spurious resilvering with nested replication. 2292 * For example, given a mirror of mirrors, (A+B)+(C+D), if only 2293 * A is out of date, we'll read from C+D, then use the data to 2294 * resilver A+B -- but we don't actually want to resilver B, just A. 2295 * The top-level mirror has no way to know this, so instead we just 2296 * discard unnecessary repairs as we work our way down the vdev tree. 2297 * The same logic applies to any form of nested replication: 2298 * ditto + mirror, RAID-Z + replacing, etc. This covers them all. 2299 */ 2300 if ((zio->io_flags & ZIO_FLAG_IO_REPAIR) && 2301 !(zio->io_flags & ZIO_FLAG_SELF_HEAL) && 2302 zio->io_txg != 0 && /* not a delegated i/o */ 2303 !vdev_dtl_contains(vd, DTL_PARTIAL, zio->io_txg, 1)) { 2304 ASSERT(zio->io_type == ZIO_TYPE_WRITE); 2305 zio_vdev_io_bypass(zio); 2306 return (ZIO_PIPELINE_CONTINUE); 2307 } 2308 2309 if (vd->vdev_ops->vdev_op_leaf && 2310 (zio->io_type == ZIO_TYPE_READ || zio->io_type == ZIO_TYPE_WRITE)) { 2311 2312 if (zio->io_type == ZIO_TYPE_READ && vdev_cache_read(zio) == 0) 2313 return (ZIO_PIPELINE_CONTINUE); 2314 2315 if ((zio = vdev_queue_io(zio)) == NULL) 2316 return (ZIO_PIPELINE_STOP); 2317 2318 if (!vdev_accessible(vd, zio)) { 2319 zio->io_error = ENXIO; 2320 zio_interrupt(zio); 2321 return (ZIO_PIPELINE_STOP); 2322 } 2323 } 2324 2325 return (vd->vdev_ops->vdev_op_io_start(zio)); 2326 } 2327 2328 static int 2329 zio_vdev_io_done(zio_t *zio) 2330 { 2331 vdev_t *vd = zio->io_vd; 2332 vdev_ops_t *ops = vd ? vd->vdev_ops : &vdev_mirror_ops; 2333 boolean_t unexpected_error = B_FALSE; 2334 2335 if (zio_wait_for_children(zio, ZIO_CHILD_VDEV, ZIO_WAIT_DONE)) 2336 return (ZIO_PIPELINE_STOP); 2337 2338 ASSERT(zio->io_type == ZIO_TYPE_READ || zio->io_type == ZIO_TYPE_WRITE); 2339 2340 if (vd != NULL && vd->vdev_ops->vdev_op_leaf) { 2341 2342 vdev_queue_io_done(zio); 2343 2344 if (zio->io_type == ZIO_TYPE_WRITE) 2345 vdev_cache_write(zio); 2346 2347 if (zio_injection_enabled && zio->io_error == 0) 2348 zio->io_error = zio_handle_device_injection(vd, 2349 zio, EIO); 2350 2351 if (zio_injection_enabled && zio->io_error == 0) 2352 zio->io_error = zio_handle_label_injection(zio, EIO); 2353 2354 if (zio->io_error) { 2355 if (!vdev_accessible(vd, zio)) { 2356 zio->io_error = ENXIO; 2357 } else { 2358 unexpected_error = B_TRUE; 2359 } 2360 } 2361 } 2362 2363 ops->vdev_op_io_done(zio); 2364 2365 if (unexpected_error) 2366 VERIFY(vdev_probe(vd, zio) == NULL); 2367 2368 return (ZIO_PIPELINE_CONTINUE); 2369 } 2370 2371 /* 2372 * For non-raidz ZIOs, we can just copy aside the bad data read from the 2373 * disk, and use that to finish the checksum ereport later. 2374 */ 2375 static void 2376 zio_vsd_default_cksum_finish(zio_cksum_report_t *zcr, 2377 const void *good_buf) 2378 { 2379 /* no processing needed */ 2380 zfs_ereport_finish_checksum(zcr, good_buf, zcr->zcr_cbdata, B_FALSE); 2381 } 2382 2383 /*ARGSUSED*/ 2384 void 2385 zio_vsd_default_cksum_report(zio_t *zio, zio_cksum_report_t *zcr, void *ignored) 2386 { 2387 void *buf = zio_buf_alloc(zio->io_size); 2388 2389 bcopy(zio->io_data, buf, zio->io_size); 2390 2391 zcr->zcr_cbinfo = zio->io_size; 2392 zcr->zcr_cbdata = buf; 2393 zcr->zcr_finish = zio_vsd_default_cksum_finish; 2394 zcr->zcr_free = zio_buf_free; 2395 } 2396 2397 static int 2398 zio_vdev_io_assess(zio_t *zio) 2399 { 2400 vdev_t *vd = zio->io_vd; 2401 2402 if (zio_wait_for_children(zio, ZIO_CHILD_VDEV, ZIO_WAIT_DONE)) 2403 return (ZIO_PIPELINE_STOP); 2404 2405 if (vd == NULL && !(zio->io_flags & ZIO_FLAG_CONFIG_WRITER)) 2406 spa_config_exit(zio->io_spa, SCL_ZIO, zio); 2407 2408 if (zio->io_vsd != NULL) { 2409 zio->io_vsd_ops->vsd_free(zio); 2410 zio->io_vsd = NULL; 2411 } 2412 2413 if (zio_injection_enabled && zio->io_error == 0) 2414 zio->io_error = zio_handle_fault_injection(zio, EIO); 2415 2416 /* 2417 * If the I/O failed, determine whether we should attempt to retry it. 2418 * 2419 * On retry, we cut in line in the issue queue, since we don't want 2420 * compression/checksumming/etc. work to prevent our (cheap) IO reissue. 2421 */ 2422 if (zio->io_error && vd == NULL && 2423 !(zio->io_flags & (ZIO_FLAG_DONT_RETRY | ZIO_FLAG_IO_RETRY))) { 2424 ASSERT(!(zio->io_flags & ZIO_FLAG_DONT_QUEUE)); /* not a leaf */ 2425 ASSERT(!(zio->io_flags & ZIO_FLAG_IO_BYPASS)); /* not a leaf */ 2426 zio->io_error = 0; 2427 zio->io_flags |= ZIO_FLAG_IO_RETRY | 2428 ZIO_FLAG_DONT_CACHE | ZIO_FLAG_DONT_AGGREGATE; 2429 zio->io_stage = ZIO_STAGE_VDEV_IO_START >> 1; 2430 zio_taskq_dispatch(zio, ZIO_TASKQ_ISSUE, 2431 zio_requeue_io_start_cut_in_line); 2432 return (ZIO_PIPELINE_STOP); 2433 } 2434 2435 /* 2436 * If we got an error on a leaf device, convert it to ENXIO 2437 * if the device is not accessible at all. 2438 */ 2439 if (zio->io_error && vd != NULL && vd->vdev_ops->vdev_op_leaf && 2440 !vdev_accessible(vd, zio)) 2441 zio->io_error = ENXIO; 2442 2443 /* 2444 * If we can't write to an interior vdev (mirror or RAID-Z), 2445 * set vdev_cant_write so that we stop trying to allocate from it. 2446 */ 2447 if (zio->io_error == ENXIO && zio->io_type == ZIO_TYPE_WRITE && 2448 vd != NULL && !vd->vdev_ops->vdev_op_leaf) 2449 vd->vdev_cant_write = B_TRUE; 2450 2451 if (zio->io_error) 2452 zio->io_pipeline = ZIO_INTERLOCK_PIPELINE; 2453 2454 return (ZIO_PIPELINE_CONTINUE); 2455 } 2456 2457 void 2458 zio_vdev_io_reissue(zio_t *zio) 2459 { 2460 ASSERT(zio->io_stage == ZIO_STAGE_VDEV_IO_START); 2461 ASSERT(zio->io_error == 0); 2462 2463 zio->io_stage >>= 1; 2464 } 2465 2466 void 2467 zio_vdev_io_redone(zio_t *zio) 2468 { 2469 ASSERT(zio->io_stage == ZIO_STAGE_VDEV_IO_DONE); 2470 2471 zio->io_stage >>= 1; 2472 } 2473 2474 void 2475 zio_vdev_io_bypass(zio_t *zio) 2476 { 2477 ASSERT(zio->io_stage == ZIO_STAGE_VDEV_IO_START); 2478 ASSERT(zio->io_error == 0); 2479 2480 zio->io_flags |= ZIO_FLAG_IO_BYPASS; 2481 zio->io_stage = ZIO_STAGE_VDEV_IO_ASSESS >> 1; 2482 } 2483 2484 /* 2485 * ========================================================================== 2486 * Generate and verify checksums 2487 * ========================================================================== 2488 */ 2489 static int 2490 zio_checksum_generate(zio_t *zio) 2491 { 2492 blkptr_t *bp = zio->io_bp; 2493 enum zio_checksum checksum; 2494 2495 if (bp == NULL) { 2496 /* 2497 * This is zio_write_phys(). 2498 * We're either generating a label checksum, or none at all. 2499 */ 2500 checksum = zio->io_prop.zp_checksum; 2501 2502 if (checksum == ZIO_CHECKSUM_OFF) 2503 return (ZIO_PIPELINE_CONTINUE); 2504 2505 ASSERT(checksum == ZIO_CHECKSUM_LABEL); 2506 } else { 2507 if (BP_IS_GANG(bp) && zio->io_child_type == ZIO_CHILD_GANG) { 2508 ASSERT(!IO_IS_ALLOCATING(zio)); 2509 checksum = ZIO_CHECKSUM_GANG_HEADER; 2510 } else { 2511 checksum = BP_GET_CHECKSUM(bp); 2512 } 2513 } 2514 2515 zio_checksum_compute(zio, checksum, zio->io_data, zio->io_size); 2516 2517 return (ZIO_PIPELINE_CONTINUE); 2518 } 2519 2520 static int 2521 zio_checksum_verify(zio_t *zio) 2522 { 2523 zio_bad_cksum_t info; 2524 blkptr_t *bp = zio->io_bp; 2525 int error; 2526 2527 ASSERT(zio->io_vd != NULL); 2528 2529 if (bp == NULL) { 2530 /* 2531 * This is zio_read_phys(). 2532 * We're either verifying a label checksum, or nothing at all. 2533 */ 2534 if (zio->io_prop.zp_checksum == ZIO_CHECKSUM_OFF) 2535 return (ZIO_PIPELINE_CONTINUE); 2536 2537 ASSERT(zio->io_prop.zp_checksum == ZIO_CHECKSUM_LABEL); 2538 } 2539 2540 if ((error = zio_checksum_error(zio, &info)) != 0) { 2541 zio->io_error = error; 2542 if (!(zio->io_flags & ZIO_FLAG_SPECULATIVE)) { 2543 zfs_ereport_start_checksum(zio->io_spa, 2544 zio->io_vd, zio, zio->io_offset, 2545 zio->io_size, NULL, &info); 2546 } 2547 } 2548 2549 return (ZIO_PIPELINE_CONTINUE); 2550 } 2551 2552 /* 2553 * Called by RAID-Z to ensure we don't compute the checksum twice. 2554 */ 2555 void 2556 zio_checksum_verified(zio_t *zio) 2557 { 2558 zio->io_pipeline &= ~ZIO_STAGE_CHECKSUM_VERIFY; 2559 } 2560 2561 /* 2562 * ========================================================================== 2563 * Error rank. Error are ranked in the order 0, ENXIO, ECKSUM, EIO, other. 2564 * An error of 0 indictes success. ENXIO indicates whole-device failure, 2565 * which may be transient (e.g. unplugged) or permament. ECKSUM and EIO 2566 * indicate errors that are specific to one I/O, and most likely permanent. 2567 * Any other error is presumed to be worse because we weren't expecting it. 2568 * ========================================================================== 2569 */ 2570 int 2571 zio_worst_error(int e1, int e2) 2572 { 2573 static int zio_error_rank[] = { 0, ENXIO, ECKSUM, EIO }; 2574 int r1, r2; 2575 2576 for (r1 = 0; r1 < sizeof (zio_error_rank) / sizeof (int); r1++) 2577 if (e1 == zio_error_rank[r1]) 2578 break; 2579 2580 for (r2 = 0; r2 < sizeof (zio_error_rank) / sizeof (int); r2++) 2581 if (e2 == zio_error_rank[r2]) 2582 break; 2583 2584 return (r1 > r2 ? e1 : e2); 2585 } 2586 2587 /* 2588 * ========================================================================== 2589 * I/O completion 2590 * ========================================================================== 2591 */ 2592 static int 2593 zio_ready(zio_t *zio) 2594 { 2595 blkptr_t *bp = zio->io_bp; 2596 zio_t *pio, *pio_next; 2597 2598 if (zio_wait_for_children(zio, ZIO_CHILD_GANG, ZIO_WAIT_READY) || 2599 zio_wait_for_children(zio, ZIO_CHILD_DDT, ZIO_WAIT_READY)) 2600 return (ZIO_PIPELINE_STOP); 2601 2602 if (zio->io_ready) { 2603 ASSERT(IO_IS_ALLOCATING(zio)); 2604 ASSERT(bp->blk_birth == zio->io_txg || BP_IS_HOLE(bp)); 2605 ASSERT(zio->io_children[ZIO_CHILD_GANG][ZIO_WAIT_READY] == 0); 2606 2607 zio->io_ready(zio); 2608 } 2609 2610 if (bp != NULL && bp != &zio->io_bp_copy) 2611 zio->io_bp_copy = *bp; 2612 2613 if (zio->io_error) 2614 zio->io_pipeline = ZIO_INTERLOCK_PIPELINE; 2615 2616 mutex_enter(&zio->io_lock); 2617 zio->io_state[ZIO_WAIT_READY] = 1; 2618 pio = zio_walk_parents(zio); 2619 mutex_exit(&zio->io_lock); 2620 2621 /* 2622 * As we notify zio's parents, new parents could be added. 2623 * New parents go to the head of zio's io_parent_list, however, 2624 * so we will (correctly) not notify them. The remainder of zio's 2625 * io_parent_list, from 'pio_next' onward, cannot change because 2626 * all parents must wait for us to be done before they can be done. 2627 */ 2628 for (; pio != NULL; pio = pio_next) { 2629 pio_next = zio_walk_parents(zio); 2630 zio_notify_parent(pio, zio, ZIO_WAIT_READY); 2631 } 2632 2633 if (zio->io_flags & ZIO_FLAG_NODATA) { 2634 if (BP_IS_GANG(bp)) { 2635 zio->io_flags &= ~ZIO_FLAG_NODATA; 2636 } else { 2637 ASSERT((uintptr_t)zio->io_data < SPA_MAXBLOCKSIZE); 2638 zio->io_pipeline &= ~ZIO_VDEV_IO_STAGES; 2639 } 2640 } 2641 2642 if (zio_injection_enabled && 2643 zio->io_spa->spa_syncing_txg == zio->io_txg) 2644 zio_handle_ignored_writes(zio); 2645 2646 return (ZIO_PIPELINE_CONTINUE); 2647 } 2648 2649 static int 2650 zio_done(zio_t *zio) 2651 { 2652 spa_t *spa = zio->io_spa; 2653 zio_t *lio = zio->io_logical; 2654 blkptr_t *bp = zio->io_bp; 2655 vdev_t *vd = zio->io_vd; 2656 uint64_t psize = zio->io_size; 2657 zio_t *pio, *pio_next; 2658 2659 /* 2660 * If our children haven't all completed, 2661 * wait for them and then repeat this pipeline stage. 2662 */ 2663 if (zio_wait_for_children(zio, ZIO_CHILD_VDEV, ZIO_WAIT_DONE) || 2664 zio_wait_for_children(zio, ZIO_CHILD_GANG, ZIO_WAIT_DONE) || 2665 zio_wait_for_children(zio, ZIO_CHILD_DDT, ZIO_WAIT_DONE) || 2666 zio_wait_for_children(zio, ZIO_CHILD_LOGICAL, ZIO_WAIT_DONE)) 2667 return (ZIO_PIPELINE_STOP); 2668 2669 for (int c = 0; c < ZIO_CHILD_TYPES; c++) 2670 for (int w = 0; w < ZIO_WAIT_TYPES; w++) 2671 ASSERT(zio->io_children[c][w] == 0); 2672 2673 if (bp != NULL) { 2674 ASSERT(bp->blk_pad[0] == 0); 2675 ASSERT(bp->blk_pad[1] == 0); 2676 ASSERT(bcmp(bp, &zio->io_bp_copy, sizeof (blkptr_t)) == 0 || 2677 (bp == zio_unique_parent(zio)->io_bp)); 2678 if (zio->io_type == ZIO_TYPE_WRITE && !BP_IS_HOLE(bp) && 2679 zio->io_bp_override == NULL && 2680 !(zio->io_flags & ZIO_FLAG_IO_REPAIR)) { 2681 ASSERT(!BP_SHOULD_BYTESWAP(bp)); 2682 ASSERT3U(zio->io_prop.zp_copies, <=, BP_GET_NDVAS(bp)); 2683 ASSERT(BP_COUNT_GANG(bp) == 0 || 2684 (BP_COUNT_GANG(bp) == BP_GET_NDVAS(bp))); 2685 } 2686 } 2687 2688 /* 2689 * If there were child vdev/gang/ddt errors, they apply to us now. 2690 */ 2691 zio_inherit_child_errors(zio, ZIO_CHILD_VDEV); 2692 zio_inherit_child_errors(zio, ZIO_CHILD_GANG); 2693 zio_inherit_child_errors(zio, ZIO_CHILD_DDT); 2694 2695 /* 2696 * If the I/O on the transformed data was successful, generate any 2697 * checksum reports now while we still have the transformed data. 2698 */ 2699 if (zio->io_error == 0) { 2700 while (zio->io_cksum_report != NULL) { 2701 zio_cksum_report_t *zcr = zio->io_cksum_report; 2702 uint64_t align = zcr->zcr_align; 2703 uint64_t asize = P2ROUNDUP(psize, align); 2704 char *abuf = zio->io_data; 2705 2706 if (asize != psize) { 2707 abuf = zio_buf_alloc(asize); 2708 bcopy(zio->io_data, abuf, psize); 2709 bzero(abuf + psize, asize - psize); 2710 } 2711 2712 zio->io_cksum_report = zcr->zcr_next; 2713 zcr->zcr_next = NULL; 2714 zcr->zcr_finish(zcr, abuf); 2715 zfs_ereport_free_checksum(zcr); 2716 2717 if (asize != psize) 2718 zio_buf_free(abuf, asize); 2719 } 2720 } 2721 2722 zio_pop_transforms(zio); /* note: may set zio->io_error */ 2723 2724 vdev_stat_update(zio, psize); 2725 2726 if (zio->io_error) { 2727 /* 2728 * If this I/O is attached to a particular vdev, 2729 * generate an error message describing the I/O failure 2730 * at the block level. We ignore these errors if the 2731 * device is currently unavailable. 2732 */ 2733 if (zio->io_error != ECKSUM && vd != NULL && !vdev_is_dead(vd)) 2734 zfs_ereport_post(FM_EREPORT_ZFS_IO, spa, vd, zio, 0, 0); 2735 2736 if ((zio->io_error == EIO || !(zio->io_flags & 2737 (ZIO_FLAG_SPECULATIVE | ZIO_FLAG_DONT_PROPAGATE))) && 2738 zio == lio) { 2739 /* 2740 * For logical I/O requests, tell the SPA to log the 2741 * error and generate a logical data ereport. 2742 */ 2743 spa_log_error(spa, zio); 2744 zfs_ereport_post(FM_EREPORT_ZFS_DATA, spa, NULL, zio, 2745 0, 0); 2746 } 2747 } 2748 2749 if (zio->io_error && zio == lio) { 2750 /* 2751 * Determine whether zio should be reexecuted. This will 2752 * propagate all the way to the root via zio_notify_parent(). 2753 */ 2754 ASSERT(vd == NULL && bp != NULL); 2755 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL); 2756 2757 if (IO_IS_ALLOCATING(zio) && 2758 !(zio->io_flags & ZIO_FLAG_CANFAIL)) { 2759 if (zio->io_error != ENOSPC) 2760 zio->io_reexecute |= ZIO_REEXECUTE_NOW; 2761 else 2762 zio->io_reexecute |= ZIO_REEXECUTE_SUSPEND; 2763 } 2764 2765 if ((zio->io_type == ZIO_TYPE_READ || 2766 zio->io_type == ZIO_TYPE_FREE) && 2767 !(zio->io_flags & ZIO_FLAG_SCAN_THREAD) && 2768 zio->io_error == ENXIO && 2769 spa_load_state(spa) == SPA_LOAD_NONE && 2770 spa_get_failmode(spa) != ZIO_FAILURE_MODE_CONTINUE) 2771 zio->io_reexecute |= ZIO_REEXECUTE_SUSPEND; 2772 2773 if (!(zio->io_flags & ZIO_FLAG_CANFAIL) && !zio->io_reexecute) 2774 zio->io_reexecute |= ZIO_REEXECUTE_SUSPEND; 2775 2776 /* 2777 * Here is a possibly good place to attempt to do 2778 * either combinatorial reconstruction or error correction 2779 * based on checksums. It also might be a good place 2780 * to send out preliminary ereports before we suspend 2781 * processing. 2782 */ 2783 } 2784 2785 /* 2786 * If there were logical child errors, they apply to us now. 2787 * We defer this until now to avoid conflating logical child 2788 * errors with errors that happened to the zio itself when 2789 * updating vdev stats and reporting FMA events above. 2790 */ 2791 zio_inherit_child_errors(zio, ZIO_CHILD_LOGICAL); 2792 2793 if ((zio->io_error || zio->io_reexecute) && 2794 IO_IS_ALLOCATING(zio) && zio->io_gang_leader == zio && 2795 !(zio->io_flags & ZIO_FLAG_IO_REWRITE)) 2796 zio_dva_unallocate(zio, zio->io_gang_tree, bp); 2797 2798 zio_gang_tree_free(&zio->io_gang_tree); 2799 2800 /* 2801 * Godfather I/Os should never suspend. 2802 */ 2803 if ((zio->io_flags & ZIO_FLAG_GODFATHER) && 2804 (zio->io_reexecute & ZIO_REEXECUTE_SUSPEND)) 2805 zio->io_reexecute = 0; 2806 2807 if (zio->io_reexecute) { 2808 /* 2809 * This is a logical I/O that wants to reexecute. 2810 * 2811 * Reexecute is top-down. When an i/o fails, if it's not 2812 * the root, it simply notifies its parent and sticks around. 2813 * The parent, seeing that it still has children in zio_done(), 2814 * does the same. This percolates all the way up to the root. 2815 * The root i/o will reexecute or suspend the entire tree. 2816 * 2817 * This approach ensures that zio_reexecute() honors 2818 * all the original i/o dependency relationships, e.g. 2819 * parents not executing until children are ready. 2820 */ 2821 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL); 2822 2823 zio->io_gang_leader = NULL; 2824 2825 mutex_enter(&zio->io_lock); 2826 zio->io_state[ZIO_WAIT_DONE] = 1; 2827 mutex_exit(&zio->io_lock); 2828 2829 /* 2830 * "The Godfather" I/O monitors its children but is 2831 * not a true parent to them. It will track them through 2832 * the pipeline but severs its ties whenever they get into 2833 * trouble (e.g. suspended). This allows "The Godfather" 2834 * I/O to return status without blocking. 2835 */ 2836 for (pio = zio_walk_parents(zio); pio != NULL; pio = pio_next) { 2837 zio_link_t *zl = zio->io_walk_link; 2838 pio_next = zio_walk_parents(zio); 2839 2840 if ((pio->io_flags & ZIO_FLAG_GODFATHER) && 2841 (zio->io_reexecute & ZIO_REEXECUTE_SUSPEND)) { 2842 zio_remove_child(pio, zio, zl); 2843 zio_notify_parent(pio, zio, ZIO_WAIT_DONE); 2844 } 2845 } 2846 2847 if ((pio = zio_unique_parent(zio)) != NULL) { 2848 /* 2849 * We're not a root i/o, so there's nothing to do 2850 * but notify our parent. Don't propagate errors 2851 * upward since we haven't permanently failed yet. 2852 */ 2853 ASSERT(!(zio->io_flags & ZIO_FLAG_GODFATHER)); 2854 zio->io_flags |= ZIO_FLAG_DONT_PROPAGATE; 2855 zio_notify_parent(pio, zio, ZIO_WAIT_DONE); 2856 } else if (zio->io_reexecute & ZIO_REEXECUTE_SUSPEND) { 2857 /* 2858 * We'd fail again if we reexecuted now, so suspend 2859 * until conditions improve (e.g. device comes online). 2860 */ 2861 zio_suspend(spa, zio); 2862 } else { 2863 /* 2864 * Reexecution is potentially a huge amount of work. 2865 * Hand it off to the otherwise-unused claim taskq. 2866 */ 2867 (void) taskq_dispatch( 2868 spa->spa_zio_taskq[ZIO_TYPE_CLAIM][ZIO_TASKQ_ISSUE], 2869 (task_func_t *)zio_reexecute, zio, TQ_SLEEP); 2870 } 2871 return (ZIO_PIPELINE_STOP); 2872 } 2873 2874 ASSERT(zio->io_child_count == 0); 2875 ASSERT(zio->io_reexecute == 0); 2876 ASSERT(zio->io_error == 0 || (zio->io_flags & ZIO_FLAG_CANFAIL)); 2877 2878 /* 2879 * Report any checksum errors, since the I/O is complete. 2880 */ 2881 while (zio->io_cksum_report != NULL) { 2882 zio_cksum_report_t *zcr = zio->io_cksum_report; 2883 zio->io_cksum_report = zcr->zcr_next; 2884 zcr->zcr_next = NULL; 2885 zcr->zcr_finish(zcr, NULL); 2886 zfs_ereport_free_checksum(zcr); 2887 } 2888 2889 /* 2890 * It is the responsibility of the done callback to ensure that this 2891 * particular zio is no longer discoverable for adoption, and as 2892 * such, cannot acquire any new parents. 2893 */ 2894 if (zio->io_done) 2895 zio->io_done(zio); 2896 2897 mutex_enter(&zio->io_lock); 2898 zio->io_state[ZIO_WAIT_DONE] = 1; 2899 mutex_exit(&zio->io_lock); 2900 2901 for (pio = zio_walk_parents(zio); pio != NULL; pio = pio_next) { 2902 zio_link_t *zl = zio->io_walk_link; 2903 pio_next = zio_walk_parents(zio); 2904 zio_remove_child(pio, zio, zl); 2905 zio_notify_parent(pio, zio, ZIO_WAIT_DONE); 2906 } 2907 2908 if (zio->io_waiter != NULL) { 2909 mutex_enter(&zio->io_lock); 2910 zio->io_executor = NULL; 2911 cv_broadcast(&zio->io_cv); 2912 mutex_exit(&zio->io_lock); 2913 } else { 2914 zio_destroy(zio); 2915 } 2916 2917 return (ZIO_PIPELINE_STOP); 2918 } 2919 2920 /* 2921 * ========================================================================== 2922 * I/O pipeline definition 2923 * ========================================================================== 2924 */ 2925 static zio_pipe_stage_t *zio_pipeline[] = { 2926 NULL, 2927 zio_read_bp_init, 2928 zio_free_bp_init, 2929 zio_issue_async, 2930 zio_write_bp_init, 2931 zio_checksum_generate, 2932 zio_ddt_read_start, 2933 zio_ddt_read_done, 2934 zio_ddt_write, 2935 zio_ddt_free, 2936 zio_gang_assemble, 2937 zio_gang_issue, 2938 zio_dva_allocate, 2939 zio_dva_free, 2940 zio_dva_claim, 2941 zio_ready, 2942 zio_vdev_io_start, 2943 zio_vdev_io_done, 2944 zio_vdev_io_assess, 2945 zio_checksum_verify, 2946 zio_done 2947 }; 2948