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 2009 Sun Microsystems, Inc. All rights reserved. 23 * Use is subject to license terms. 24 */ 25 26 #include <sys/zfs_context.h> 27 #include <sys/fm/fs/zfs.h> 28 #include <sys/spa.h> 29 #include <sys/txg.h> 30 #include <sys/spa_impl.h> 31 #include <sys/vdev_impl.h> 32 #include <sys/zio_impl.h> 33 #include <sys/zio_compress.h> 34 #include <sys/zio_checksum.h> 35 #include <sys/dmu_objset.h> 36 #include <sys/arc.h> 37 #include <sys/ddt.h> 38 39 /* 40 * ========================================================================== 41 * I/O priority table 42 * ========================================================================== 43 */ 44 uint8_t zio_priority_table[ZIO_PRIORITY_TABLE_SIZE] = { 45 0, /* ZIO_PRIORITY_NOW */ 46 0, /* ZIO_PRIORITY_SYNC_READ */ 47 0, /* ZIO_PRIORITY_SYNC_WRITE */ 48 0, /* ZIO_PRIORITY_LOG_WRITE */ 49 1, /* ZIO_PRIORITY_CACHE_FILL */ 50 1, /* ZIO_PRIORITY_AGG */ 51 4, /* ZIO_PRIORITY_FREE */ 52 4, /* ZIO_PRIORITY_ASYNC_WRITE */ 53 6, /* ZIO_PRIORITY_ASYNC_READ */ 54 10, /* ZIO_PRIORITY_RESILVER */ 55 20, /* ZIO_PRIORITY_SCRUB */ 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_enqueue_deferred(&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 ASSERT(!BP_IS_HOLE(bp)); 665 ASSERT(spa_syncing_txg(spa) == txg); 666 ASSERT(spa_sync_pass(spa) <= SYNC_PASS_DEFERRED_FREE); 667 668 zio = zio_create(pio, spa, txg, bp, NULL, BP_GET_PSIZE(bp), 669 NULL, NULL, ZIO_TYPE_FREE, ZIO_PRIORITY_FREE, flags, 670 NULL, 0, NULL, ZIO_STAGE_OPEN, ZIO_FREE_PIPELINE); 671 672 return (zio); 673 } 674 675 zio_t * 676 zio_claim(zio_t *pio, spa_t *spa, uint64_t txg, const blkptr_t *bp, 677 zio_done_func_t *done, void *private, enum zio_flag flags) 678 { 679 zio_t *zio; 680 681 /* 682 * A claim is an allocation of a specific block. Claims are needed 683 * to support immediate writes in the intent log. The issue is that 684 * immediate writes contain committed data, but in a txg that was 685 * *not* committed. Upon opening the pool after an unclean shutdown, 686 * the intent log claims all blocks that contain immediate write data 687 * so that the SPA knows they're in use. 688 * 689 * All claims *must* be resolved in the first txg -- before the SPA 690 * starts allocating blocks -- so that nothing is allocated twice. 691 * If txg == 0 we just verify that the block is claimable. 692 */ 693 ASSERT3U(spa->spa_uberblock.ub_rootbp.blk_birth, <, spa_first_txg(spa)); 694 ASSERT(txg == spa_first_txg(spa) || txg == 0); 695 ASSERT(!BP_GET_DEDUP(bp) || !spa_writeable(spa)); /* zdb(1M) */ 696 697 zio = zio_create(pio, spa, txg, bp, NULL, BP_GET_PSIZE(bp), 698 done, private, ZIO_TYPE_CLAIM, ZIO_PRIORITY_NOW, flags, 699 NULL, 0, NULL, ZIO_STAGE_OPEN, ZIO_CLAIM_PIPELINE); 700 701 return (zio); 702 } 703 704 zio_t * 705 zio_ioctl(zio_t *pio, spa_t *spa, vdev_t *vd, int cmd, 706 zio_done_func_t *done, void *private, int priority, enum zio_flag flags) 707 { 708 zio_t *zio; 709 int c; 710 711 if (vd->vdev_children == 0) { 712 zio = zio_create(pio, spa, 0, NULL, NULL, 0, done, private, 713 ZIO_TYPE_IOCTL, priority, flags, vd, 0, NULL, 714 ZIO_STAGE_OPEN, ZIO_IOCTL_PIPELINE); 715 716 zio->io_cmd = cmd; 717 } else { 718 zio = zio_null(pio, spa, NULL, NULL, NULL, flags); 719 720 for (c = 0; c < vd->vdev_children; c++) 721 zio_nowait(zio_ioctl(zio, spa, vd->vdev_child[c], cmd, 722 done, private, priority, flags)); 723 } 724 725 return (zio); 726 } 727 728 zio_t * 729 zio_read_phys(zio_t *pio, vdev_t *vd, uint64_t offset, uint64_t size, 730 void *data, int checksum, zio_done_func_t *done, void *private, 731 int priority, enum zio_flag flags, boolean_t labels) 732 { 733 zio_t *zio; 734 735 ASSERT(vd->vdev_children == 0); 736 ASSERT(!labels || offset + size <= VDEV_LABEL_START_SIZE || 737 offset >= vd->vdev_psize - VDEV_LABEL_END_SIZE); 738 ASSERT3U(offset + size, <=, vd->vdev_psize); 739 740 zio = zio_create(pio, vd->vdev_spa, 0, NULL, data, size, done, private, 741 ZIO_TYPE_READ, priority, flags, vd, offset, NULL, 742 ZIO_STAGE_OPEN, ZIO_READ_PHYS_PIPELINE); 743 744 zio->io_prop.zp_checksum = checksum; 745 746 return (zio); 747 } 748 749 zio_t * 750 zio_write_phys(zio_t *pio, vdev_t *vd, uint64_t offset, uint64_t size, 751 void *data, int checksum, zio_done_func_t *done, void *private, 752 int priority, enum zio_flag flags, boolean_t labels) 753 { 754 zio_t *zio; 755 756 ASSERT(vd->vdev_children == 0); 757 ASSERT(!labels || offset + size <= VDEV_LABEL_START_SIZE || 758 offset >= vd->vdev_psize - VDEV_LABEL_END_SIZE); 759 ASSERT3U(offset + size, <=, vd->vdev_psize); 760 761 zio = zio_create(pio, vd->vdev_spa, 0, NULL, data, size, done, private, 762 ZIO_TYPE_WRITE, priority, flags, vd, offset, NULL, 763 ZIO_STAGE_OPEN, ZIO_WRITE_PHYS_PIPELINE); 764 765 zio->io_prop.zp_checksum = checksum; 766 767 if (zio_checksum_table[checksum].ci_zbt) { 768 /* 769 * zbt checksums are necessarily destructive -- they modify 770 * the end of the write buffer to hold the verifier/checksum. 771 * Therefore, we must make a local copy in case the data is 772 * being written to multiple places in parallel. 773 */ 774 void *wbuf = zio_buf_alloc(size); 775 bcopy(data, wbuf, size); 776 zio_push_transform(zio, wbuf, size, size, NULL); 777 } 778 779 return (zio); 780 } 781 782 /* 783 * Create a child I/O to do some work for us. 784 */ 785 zio_t * 786 zio_vdev_child_io(zio_t *pio, blkptr_t *bp, vdev_t *vd, uint64_t offset, 787 void *data, uint64_t size, int type, int priority, enum zio_flag flags, 788 zio_done_func_t *done, void *private) 789 { 790 enum zio_stage pipeline = ZIO_VDEV_CHILD_PIPELINE; 791 zio_t *zio; 792 793 ASSERT(vd->vdev_parent == 794 (pio->io_vd ? pio->io_vd : pio->io_spa->spa_root_vdev)); 795 796 if (type == ZIO_TYPE_READ && bp != NULL) { 797 /* 798 * If we have the bp, then the child should perform the 799 * checksum and the parent need not. This pushes error 800 * detection as close to the leaves as possible and 801 * eliminates redundant checksums in the interior nodes. 802 */ 803 pipeline |= ZIO_STAGE_CHECKSUM_VERIFY; 804 pio->io_pipeline &= ~ZIO_STAGE_CHECKSUM_VERIFY; 805 } 806 807 if (vd->vdev_children == 0) 808 offset += VDEV_LABEL_START_SIZE; 809 810 flags |= ZIO_VDEV_CHILD_FLAGS(pio) | ZIO_FLAG_DONT_PROPAGATE; 811 812 /* 813 * If we've decided to do a repair, the write is not speculative -- 814 * even if the original read was. 815 */ 816 if (flags & ZIO_FLAG_IO_REPAIR) 817 flags &= ~ZIO_FLAG_SPECULATIVE; 818 819 zio = zio_create(pio, pio->io_spa, pio->io_txg, bp, data, size, 820 done, private, type, priority, flags, vd, offset, &pio->io_bookmark, 821 ZIO_STAGE_VDEV_IO_START >> 1, pipeline); 822 823 return (zio); 824 } 825 826 zio_t * 827 zio_vdev_delegated_io(vdev_t *vd, uint64_t offset, void *data, uint64_t size, 828 int type, int priority, enum zio_flag flags, 829 zio_done_func_t *done, void *private) 830 { 831 zio_t *zio; 832 833 ASSERT(vd->vdev_ops->vdev_op_leaf); 834 835 zio = zio_create(NULL, vd->vdev_spa, 0, NULL, 836 data, size, done, private, type, priority, 837 flags | ZIO_FLAG_CANFAIL | ZIO_FLAG_DONT_RETRY, 838 vd, offset, NULL, 839 ZIO_STAGE_VDEV_IO_START >> 1, ZIO_VDEV_CHILD_PIPELINE); 840 841 return (zio); 842 } 843 844 void 845 zio_flush(zio_t *zio, vdev_t *vd) 846 { 847 zio_nowait(zio_ioctl(zio, zio->io_spa, vd, DKIOCFLUSHWRITECACHE, 848 NULL, NULL, ZIO_PRIORITY_NOW, 849 ZIO_FLAG_CANFAIL | ZIO_FLAG_DONT_PROPAGATE | ZIO_FLAG_DONT_RETRY)); 850 } 851 852 /* 853 * ========================================================================== 854 * Prepare to read and write logical blocks 855 * ========================================================================== 856 */ 857 858 static int 859 zio_read_bp_init(zio_t *zio) 860 { 861 blkptr_t *bp = zio->io_bp; 862 863 if (BP_GET_COMPRESS(bp) != ZIO_COMPRESS_OFF && 864 zio->io_child_type == ZIO_CHILD_LOGICAL && 865 !(zio->io_flags & ZIO_FLAG_RAW)) { 866 uint64_t psize = BP_GET_PSIZE(bp); 867 void *cbuf = zio_buf_alloc(psize); 868 869 zio_push_transform(zio, cbuf, psize, psize, zio_decompress); 870 } 871 872 if (!dmu_ot[BP_GET_TYPE(bp)].ot_metadata && BP_GET_LEVEL(bp) == 0) 873 zio->io_flags |= ZIO_FLAG_DONT_CACHE; 874 875 if (BP_GET_TYPE(bp) == DMU_OT_DDT_ZAP) 876 zio->io_flags |= ZIO_FLAG_DONT_CACHE; 877 878 if (BP_GET_DEDUP(bp) && zio->io_child_type == ZIO_CHILD_LOGICAL) 879 zio->io_pipeline = ZIO_DDT_READ_PIPELINE; 880 881 return (ZIO_PIPELINE_CONTINUE); 882 } 883 884 static int 885 zio_write_bp_init(zio_t *zio) 886 { 887 spa_t *spa = zio->io_spa; 888 zio_prop_t *zp = &zio->io_prop; 889 enum zio_compress compress = zp->zp_compress; 890 blkptr_t *bp = zio->io_bp; 891 uint64_t lsize = zio->io_size; 892 uint64_t psize = lsize; 893 int pass = 1; 894 895 /* 896 * If our children haven't all reached the ready stage, 897 * wait for them and then repeat this pipeline stage. 898 */ 899 if (zio_wait_for_children(zio, ZIO_CHILD_GANG, ZIO_WAIT_READY) || 900 zio_wait_for_children(zio, ZIO_CHILD_LOGICAL, ZIO_WAIT_READY)) 901 return (ZIO_PIPELINE_STOP); 902 903 if (!IO_IS_ALLOCATING(zio)) 904 return (ZIO_PIPELINE_CONTINUE); 905 906 ASSERT(zio->io_child_type != ZIO_CHILD_DDT); 907 908 if (zio->io_bp_override) { 909 ASSERT(bp->blk_birth != zio->io_txg); 910 ASSERT(BP_GET_DEDUP(zio->io_bp_override) == 0); 911 912 *bp = *zio->io_bp_override; 913 zio->io_pipeline = ZIO_INTERLOCK_PIPELINE; 914 915 if (BP_IS_HOLE(bp) || !zp->zp_dedup) 916 return (ZIO_PIPELINE_CONTINUE); 917 918 ASSERT(zio_checksum_table[zp->zp_checksum].ci_dedup || 919 zp->zp_dedup_verify); 920 921 if (BP_GET_CHECKSUM(bp) == zp->zp_checksum) { 922 BP_SET_DEDUP(bp, 1); 923 zio->io_pipeline |= ZIO_STAGE_DDT_WRITE; 924 return (ZIO_PIPELINE_CONTINUE); 925 } 926 zio->io_bp_override = NULL; 927 BP_ZERO(bp); 928 } 929 930 if (bp->blk_birth == zio->io_txg) { 931 /* 932 * We're rewriting an existing block, which means we're 933 * working on behalf of spa_sync(). For spa_sync() to 934 * converge, it must eventually be the case that we don't 935 * have to allocate new blocks. But compression changes 936 * the blocksize, which forces a reallocate, and makes 937 * convergence take longer. Therefore, after the first 938 * few passes, stop compressing to ensure convergence. 939 */ 940 pass = spa_sync_pass(spa); 941 942 ASSERT(zio->io_txg == spa_syncing_txg(spa)); 943 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL); 944 ASSERT(!BP_GET_DEDUP(bp)); 945 946 if (pass > SYNC_PASS_DONT_COMPRESS) 947 compress = ZIO_COMPRESS_OFF; 948 949 /* Make sure someone doesn't change their mind on overwrites */ 950 ASSERT(MIN(zp->zp_copies + BP_IS_GANG(bp), 951 spa_max_replication(spa)) == BP_GET_NDVAS(bp)); 952 } 953 954 if (compress != ZIO_COMPRESS_OFF) { 955 void *cbuf = zio_buf_alloc(lsize); 956 psize = zio_compress_data(compress, zio->io_data, cbuf, lsize); 957 if (psize == 0 || psize == lsize) { 958 compress = ZIO_COMPRESS_OFF; 959 zio_buf_free(cbuf, lsize); 960 } else { 961 ASSERT(psize < lsize); 962 zio_push_transform(zio, cbuf, psize, lsize, NULL); 963 } 964 } 965 966 /* 967 * The final pass of spa_sync() must be all rewrites, but the first 968 * few passes offer a trade-off: allocating blocks defers convergence, 969 * but newly allocated blocks are sequential, so they can be written 970 * to disk faster. Therefore, we allow the first few passes of 971 * spa_sync() to allocate new blocks, but force rewrites after that. 972 * There should only be a handful of blocks after pass 1 in any case. 973 */ 974 if (bp->blk_birth == zio->io_txg && BP_GET_PSIZE(bp) == psize && 975 pass > SYNC_PASS_REWRITE) { 976 ASSERT(psize != 0); 977 enum zio_stage gang_stages = zio->io_pipeline & ZIO_GANG_STAGES; 978 zio->io_pipeline = ZIO_REWRITE_PIPELINE | gang_stages; 979 zio->io_flags |= ZIO_FLAG_IO_REWRITE; 980 } else { 981 BP_ZERO(bp); 982 zio->io_pipeline = ZIO_WRITE_PIPELINE; 983 } 984 985 if (psize == 0) { 986 zio->io_pipeline = ZIO_INTERLOCK_PIPELINE; 987 } else { 988 ASSERT(zp->zp_checksum != ZIO_CHECKSUM_GANG_HEADER); 989 BP_SET_LSIZE(bp, lsize); 990 BP_SET_PSIZE(bp, psize); 991 BP_SET_COMPRESS(bp, compress); 992 BP_SET_CHECKSUM(bp, zp->zp_checksum); 993 BP_SET_TYPE(bp, zp->zp_type); 994 BP_SET_LEVEL(bp, zp->zp_level); 995 BP_SET_DEDUP(bp, zp->zp_dedup); 996 BP_SET_BYTEORDER(bp, ZFS_HOST_BYTEORDER); 997 if (zp->zp_dedup) { 998 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL); 999 ASSERT(!(zio->io_flags & ZIO_FLAG_IO_REWRITE)); 1000 zio->io_pipeline = ZIO_DDT_WRITE_PIPELINE; 1001 } 1002 } 1003 1004 return (ZIO_PIPELINE_CONTINUE); 1005 } 1006 1007 static int 1008 zio_free_bp_init(zio_t *zio) 1009 { 1010 blkptr_t *bp = zio->io_bp; 1011 1012 if (zio->io_child_type == ZIO_CHILD_LOGICAL) { 1013 if (BP_GET_DEDUP(bp)) 1014 zio->io_pipeline = ZIO_DDT_FREE_PIPELINE; 1015 else 1016 arc_free(zio->io_spa, bp); 1017 } 1018 1019 return (ZIO_PIPELINE_CONTINUE); 1020 } 1021 1022 /* 1023 * ========================================================================== 1024 * Execute the I/O pipeline 1025 * ========================================================================== 1026 */ 1027 1028 static void 1029 zio_taskq_dispatch(zio_t *zio, enum zio_taskq_type q, boolean_t cutinline) 1030 { 1031 spa_t *spa = zio->io_spa; 1032 zio_type_t t = zio->io_type; 1033 int flags = TQ_SLEEP | (cutinline ? TQ_FRONT : 0); 1034 1035 /* 1036 * If we're a config writer or a probe, the normal issue and 1037 * interrupt threads may all be blocked waiting for the config lock. 1038 * In this case, select the otherwise-unused taskq for ZIO_TYPE_NULL. 1039 */ 1040 if (zio->io_flags & (ZIO_FLAG_CONFIG_WRITER | ZIO_FLAG_PROBE)) 1041 t = ZIO_TYPE_NULL; 1042 1043 /* 1044 * A similar issue exists for the L2ARC write thread until L2ARC 2.0. 1045 */ 1046 if (t == ZIO_TYPE_WRITE && zio->io_vd && zio->io_vd->vdev_aux) 1047 t = ZIO_TYPE_NULL; 1048 1049 /* 1050 * If this is a high priority I/O, then use the high priority taskq. 1051 */ 1052 if (zio->io_priority == ZIO_PRIORITY_NOW && 1053 spa->spa_zio_taskq[t][q + 1] != NULL) 1054 q++; 1055 1056 ASSERT3U(q, <, ZIO_TASKQ_TYPES); 1057 (void) taskq_dispatch(spa->spa_zio_taskq[t][q], 1058 (task_func_t *)zio_execute, zio, flags); 1059 } 1060 1061 static boolean_t 1062 zio_taskq_member(zio_t *zio, enum zio_taskq_type q) 1063 { 1064 kthread_t *executor = zio->io_executor; 1065 spa_t *spa = zio->io_spa; 1066 1067 for (zio_type_t t = 0; t < ZIO_TYPES; t++) 1068 if (taskq_member(spa->spa_zio_taskq[t][q], executor)) 1069 return (B_TRUE); 1070 1071 return (B_FALSE); 1072 } 1073 1074 static int 1075 zio_issue_async(zio_t *zio) 1076 { 1077 zio_taskq_dispatch(zio, ZIO_TASKQ_ISSUE, B_FALSE); 1078 1079 return (ZIO_PIPELINE_STOP); 1080 } 1081 1082 void 1083 zio_interrupt(zio_t *zio) 1084 { 1085 zio_taskq_dispatch(zio, ZIO_TASKQ_INTERRUPT, B_FALSE); 1086 } 1087 1088 /* 1089 * Execute the I/O pipeline until one of the following occurs: 1090 * (1) the I/O completes; (2) the pipeline stalls waiting for 1091 * dependent child I/Os; (3) the I/O issues, so we're waiting 1092 * for an I/O completion interrupt; (4) the I/O is delegated by 1093 * vdev-level caching or aggregation; (5) the I/O is deferred 1094 * due to vdev-level queueing; (6) the I/O is handed off to 1095 * another thread. In all cases, the pipeline stops whenever 1096 * there's no CPU work; it never burns a thread in cv_wait(). 1097 * 1098 * There's no locking on io_stage because there's no legitimate way 1099 * for multiple threads to be attempting to process the same I/O. 1100 */ 1101 static zio_pipe_stage_t *zio_pipeline[]; 1102 1103 void 1104 zio_execute(zio_t *zio) 1105 { 1106 zio->io_executor = curthread; 1107 1108 while (zio->io_stage < ZIO_STAGE_DONE) { 1109 enum zio_stage pipeline = zio->io_pipeline; 1110 enum zio_stage stage = zio->io_stage; 1111 int rv; 1112 1113 ASSERT(!MUTEX_HELD(&zio->io_lock)); 1114 ASSERT(ISP2(stage)); 1115 ASSERT(zio->io_stall == NULL); 1116 1117 do { 1118 stage <<= 1; 1119 } while ((stage & pipeline) == 0); 1120 1121 ASSERT(stage <= ZIO_STAGE_DONE); 1122 1123 /* 1124 * If we are in interrupt context and this pipeline stage 1125 * will grab a config lock that is held across I/O, 1126 * or may wait for an I/O that needs an interrupt thread 1127 * to complete, issue async to avoid deadlock. 1128 * 1129 * For VDEV_IO_START, we cut in line so that the io will 1130 * be sent to disk promptly. 1131 */ 1132 if ((stage & ZIO_BLOCKING_STAGES) && zio->io_vd == NULL && 1133 zio_taskq_member(zio, ZIO_TASKQ_INTERRUPT)) { 1134 boolean_t cut = (stage == ZIO_STAGE_VDEV_IO_START) ? 1135 zio_requeue_io_start_cut_in_line : B_FALSE; 1136 zio_taskq_dispatch(zio, ZIO_TASKQ_ISSUE, cut); 1137 return; 1138 } 1139 1140 zio->io_stage = stage; 1141 rv = zio_pipeline[highbit(stage) - 1](zio); 1142 1143 if (rv == ZIO_PIPELINE_STOP) 1144 return; 1145 1146 ASSERT(rv == ZIO_PIPELINE_CONTINUE); 1147 } 1148 } 1149 1150 /* 1151 * ========================================================================== 1152 * Initiate I/O, either sync or async 1153 * ========================================================================== 1154 */ 1155 int 1156 zio_wait(zio_t *zio) 1157 { 1158 int error; 1159 1160 ASSERT(zio->io_stage == ZIO_STAGE_OPEN); 1161 ASSERT(zio->io_executor == NULL); 1162 1163 zio->io_waiter = curthread; 1164 1165 zio_execute(zio); 1166 1167 mutex_enter(&zio->io_lock); 1168 while (zio->io_executor != NULL) 1169 cv_wait(&zio->io_cv, &zio->io_lock); 1170 mutex_exit(&zio->io_lock); 1171 1172 error = zio->io_error; 1173 zio_destroy(zio); 1174 1175 return (error); 1176 } 1177 1178 void 1179 zio_nowait(zio_t *zio) 1180 { 1181 ASSERT(zio->io_executor == NULL); 1182 1183 if (zio->io_child_type == ZIO_CHILD_LOGICAL && 1184 zio_unique_parent(zio) == NULL) { 1185 /* 1186 * This is a logical async I/O with no parent to wait for it. 1187 * We add it to the spa_async_root_zio "Godfather" I/O which 1188 * will ensure they complete prior to unloading the pool. 1189 */ 1190 spa_t *spa = zio->io_spa; 1191 1192 zio_add_child(spa->spa_async_zio_root, zio); 1193 } 1194 1195 zio_execute(zio); 1196 } 1197 1198 /* 1199 * ========================================================================== 1200 * Reexecute or suspend/resume failed I/O 1201 * ========================================================================== 1202 */ 1203 1204 static void 1205 zio_reexecute(zio_t *pio) 1206 { 1207 zio_t *cio, *cio_next; 1208 1209 ASSERT(pio->io_child_type == ZIO_CHILD_LOGICAL); 1210 ASSERT(pio->io_orig_stage == ZIO_STAGE_OPEN); 1211 ASSERT(pio->io_gang_leader == NULL); 1212 ASSERT(pio->io_gang_tree == NULL); 1213 1214 pio->io_flags = pio->io_orig_flags; 1215 pio->io_stage = pio->io_orig_stage; 1216 pio->io_pipeline = pio->io_orig_pipeline; 1217 pio->io_reexecute = 0; 1218 pio->io_error = 0; 1219 for (int w = 0; w < ZIO_WAIT_TYPES; w++) 1220 pio->io_state[w] = 0; 1221 for (int c = 0; c < ZIO_CHILD_TYPES; c++) 1222 pio->io_child_error[c] = 0; 1223 1224 if (IO_IS_ALLOCATING(pio)) 1225 BP_ZERO(pio->io_bp); 1226 1227 /* 1228 * As we reexecute pio's children, new children could be created. 1229 * New children go to the head of pio's io_child_list, however, 1230 * so we will (correctly) not reexecute them. The key is that 1231 * the remainder of pio's io_child_list, from 'cio_next' onward, 1232 * cannot be affected by any side effects of reexecuting 'cio'. 1233 */ 1234 for (cio = zio_walk_children(pio); cio != NULL; cio = cio_next) { 1235 cio_next = zio_walk_children(pio); 1236 mutex_enter(&pio->io_lock); 1237 for (int w = 0; w < ZIO_WAIT_TYPES; w++) 1238 pio->io_children[cio->io_child_type][w]++; 1239 mutex_exit(&pio->io_lock); 1240 zio_reexecute(cio); 1241 } 1242 1243 /* 1244 * Now that all children have been reexecuted, execute the parent. 1245 * We don't reexecute "The Godfather" I/O here as it's the 1246 * responsibility of the caller to wait on him. 1247 */ 1248 if (!(pio->io_flags & ZIO_FLAG_GODFATHER)) 1249 zio_execute(pio); 1250 } 1251 1252 void 1253 zio_suspend(spa_t *spa, zio_t *zio) 1254 { 1255 if (spa_get_failmode(spa) == ZIO_FAILURE_MODE_PANIC) 1256 fm_panic("Pool '%s' has encountered an uncorrectable I/O " 1257 "failure and the failure mode property for this pool " 1258 "is set to panic.", spa_name(spa)); 1259 1260 zfs_ereport_post(FM_EREPORT_ZFS_IO_FAILURE, spa, NULL, NULL, 0, 0); 1261 1262 mutex_enter(&spa->spa_suspend_lock); 1263 1264 if (spa->spa_suspend_zio_root == NULL) 1265 spa->spa_suspend_zio_root = zio_root(spa, NULL, NULL, 1266 ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE | 1267 ZIO_FLAG_GODFATHER); 1268 1269 spa->spa_suspended = B_TRUE; 1270 1271 if (zio != NULL) { 1272 ASSERT(!(zio->io_flags & ZIO_FLAG_GODFATHER)); 1273 ASSERT(zio != spa->spa_suspend_zio_root); 1274 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL); 1275 ASSERT(zio_unique_parent(zio) == NULL); 1276 ASSERT(zio->io_stage == ZIO_STAGE_DONE); 1277 zio_add_child(spa->spa_suspend_zio_root, zio); 1278 } 1279 1280 mutex_exit(&spa->spa_suspend_lock); 1281 } 1282 1283 int 1284 zio_resume(spa_t *spa) 1285 { 1286 zio_t *pio; 1287 1288 /* 1289 * Reexecute all previously suspended i/o. 1290 */ 1291 mutex_enter(&spa->spa_suspend_lock); 1292 spa->spa_suspended = B_FALSE; 1293 cv_broadcast(&spa->spa_suspend_cv); 1294 pio = spa->spa_suspend_zio_root; 1295 spa->spa_suspend_zio_root = NULL; 1296 mutex_exit(&spa->spa_suspend_lock); 1297 1298 if (pio == NULL) 1299 return (0); 1300 1301 zio_reexecute(pio); 1302 return (zio_wait(pio)); 1303 } 1304 1305 void 1306 zio_resume_wait(spa_t *spa) 1307 { 1308 mutex_enter(&spa->spa_suspend_lock); 1309 while (spa_suspended(spa)) 1310 cv_wait(&spa->spa_suspend_cv, &spa->spa_suspend_lock); 1311 mutex_exit(&spa->spa_suspend_lock); 1312 } 1313 1314 /* 1315 * ========================================================================== 1316 * Gang blocks. 1317 * 1318 * A gang block is a collection of small blocks that looks to the DMU 1319 * like one large block. When zio_dva_allocate() cannot find a block 1320 * of the requested size, due to either severe fragmentation or the pool 1321 * being nearly full, it calls zio_write_gang_block() to construct the 1322 * block from smaller fragments. 1323 * 1324 * A gang block consists of a gang header (zio_gbh_phys_t) and up to 1325 * three (SPA_GBH_NBLKPTRS) gang members. The gang header is just like 1326 * an indirect block: it's an array of block pointers. It consumes 1327 * only one sector and hence is allocatable regardless of fragmentation. 1328 * The gang header's bps point to its gang members, which hold the data. 1329 * 1330 * Gang blocks are self-checksumming, using the bp's <vdev, offset, txg> 1331 * as the verifier to ensure uniqueness of the SHA256 checksum. 1332 * Critically, the gang block bp's blk_cksum is the checksum of the data, 1333 * not the gang header. This ensures that data block signatures (needed for 1334 * deduplication) are independent of how the block is physically stored. 1335 * 1336 * Gang blocks can be nested: a gang member may itself be a gang block. 1337 * Thus every gang block is a tree in which root and all interior nodes are 1338 * gang headers, and the leaves are normal blocks that contain user data. 1339 * The root of the gang tree is called the gang leader. 1340 * 1341 * To perform any operation (read, rewrite, free, claim) on a gang block, 1342 * zio_gang_assemble() first assembles the gang tree (minus data leaves) 1343 * in the io_gang_tree field of the original logical i/o by recursively 1344 * reading the gang leader and all gang headers below it. This yields 1345 * an in-core tree containing the contents of every gang header and the 1346 * bps for every constituent of the gang block. 1347 * 1348 * With the gang tree now assembled, zio_gang_issue() just walks the gang tree 1349 * and invokes a callback on each bp. To free a gang block, zio_gang_issue() 1350 * calls zio_free_gang() -- a trivial wrapper around zio_free() -- for each bp. 1351 * zio_claim_gang() provides a similarly trivial wrapper for zio_claim(). 1352 * zio_read_gang() is a wrapper around zio_read() that omits reading gang 1353 * headers, since we already have those in io_gang_tree. zio_rewrite_gang() 1354 * performs a zio_rewrite() of the data or, for gang headers, a zio_rewrite() 1355 * of the gang header plus zio_checksum_compute() of the data to update the 1356 * gang header's blk_cksum as described above. 1357 * 1358 * The two-phase assemble/issue model solves the problem of partial failure -- 1359 * what if you'd freed part of a gang block but then couldn't read the 1360 * gang header for another part? Assembling the entire gang tree first 1361 * ensures that all the necessary gang header I/O has succeeded before 1362 * starting the actual work of free, claim, or write. Once the gang tree 1363 * is assembled, free and claim are in-memory operations that cannot fail. 1364 * 1365 * In the event that a gang write fails, zio_dva_unallocate() walks the 1366 * gang tree to immediately free (i.e. insert back into the space map) 1367 * everything we've allocated. This ensures that we don't get ENOSPC 1368 * errors during repeated suspend/resume cycles due to a flaky device. 1369 * 1370 * Gang rewrites only happen during sync-to-convergence. If we can't assemble 1371 * the gang tree, we won't modify the block, so we can safely defer the free 1372 * (knowing that the block is still intact). If we *can* assemble the gang 1373 * tree, then even if some of the rewrites fail, zio_dva_unallocate() will free 1374 * each constituent bp and we can allocate a new block on the next sync pass. 1375 * 1376 * In all cases, the gang tree allows complete recovery from partial failure. 1377 * ========================================================================== 1378 */ 1379 1380 static zio_t * 1381 zio_read_gang(zio_t *pio, blkptr_t *bp, zio_gang_node_t *gn, void *data) 1382 { 1383 if (gn != NULL) 1384 return (pio); 1385 1386 return (zio_read(pio, pio->io_spa, bp, data, BP_GET_PSIZE(bp), 1387 NULL, NULL, pio->io_priority, ZIO_GANG_CHILD_FLAGS(pio), 1388 &pio->io_bookmark)); 1389 } 1390 1391 zio_t * 1392 zio_rewrite_gang(zio_t *pio, blkptr_t *bp, zio_gang_node_t *gn, void *data) 1393 { 1394 zio_t *zio; 1395 1396 if (gn != NULL) { 1397 zio = zio_rewrite(pio, pio->io_spa, pio->io_txg, bp, 1398 gn->gn_gbh, SPA_GANGBLOCKSIZE, NULL, NULL, pio->io_priority, 1399 ZIO_GANG_CHILD_FLAGS(pio), &pio->io_bookmark); 1400 /* 1401 * As we rewrite each gang header, the pipeline will compute 1402 * a new gang block header checksum for it; but no one will 1403 * compute a new data checksum, so we do that here. The one 1404 * exception is the gang leader: the pipeline already computed 1405 * its data checksum because that stage precedes gang assembly. 1406 * (Presently, nothing actually uses interior data checksums; 1407 * this is just good hygiene.) 1408 */ 1409 if (gn != pio->io_gang_leader->io_gang_tree) { 1410 zio_checksum_compute(zio, BP_GET_CHECKSUM(bp), 1411 data, BP_GET_PSIZE(bp)); 1412 } 1413 /* 1414 * If we are here to damage data for testing purposes, 1415 * leave the GBH alone so that we can detect the damage. 1416 */ 1417 if (pio->io_gang_leader->io_flags & ZIO_FLAG_INDUCE_DAMAGE) 1418 zio->io_pipeline &= ~ZIO_VDEV_IO_STAGES; 1419 } else { 1420 zio = zio_rewrite(pio, pio->io_spa, pio->io_txg, bp, 1421 data, BP_GET_PSIZE(bp), NULL, NULL, pio->io_priority, 1422 ZIO_GANG_CHILD_FLAGS(pio), &pio->io_bookmark); 1423 } 1424 1425 return (zio); 1426 } 1427 1428 /* ARGSUSED */ 1429 zio_t * 1430 zio_free_gang(zio_t *pio, blkptr_t *bp, zio_gang_node_t *gn, void *data) 1431 { 1432 return (zio_free_sync(pio, pio->io_spa, pio->io_txg, bp, 1433 ZIO_GANG_CHILD_FLAGS(pio))); 1434 } 1435 1436 /* ARGSUSED */ 1437 zio_t * 1438 zio_claim_gang(zio_t *pio, blkptr_t *bp, zio_gang_node_t *gn, void *data) 1439 { 1440 return (zio_claim(pio, pio->io_spa, pio->io_txg, bp, 1441 NULL, NULL, ZIO_GANG_CHILD_FLAGS(pio))); 1442 } 1443 1444 static zio_gang_issue_func_t *zio_gang_issue_func[ZIO_TYPES] = { 1445 NULL, 1446 zio_read_gang, 1447 zio_rewrite_gang, 1448 zio_free_gang, 1449 zio_claim_gang, 1450 NULL 1451 }; 1452 1453 static void zio_gang_tree_assemble_done(zio_t *zio); 1454 1455 static zio_gang_node_t * 1456 zio_gang_node_alloc(zio_gang_node_t **gnpp) 1457 { 1458 zio_gang_node_t *gn; 1459 1460 ASSERT(*gnpp == NULL); 1461 1462 gn = kmem_zalloc(sizeof (*gn), KM_SLEEP); 1463 gn->gn_gbh = zio_buf_alloc(SPA_GANGBLOCKSIZE); 1464 *gnpp = gn; 1465 1466 return (gn); 1467 } 1468 1469 static void 1470 zio_gang_node_free(zio_gang_node_t **gnpp) 1471 { 1472 zio_gang_node_t *gn = *gnpp; 1473 1474 for (int g = 0; g < SPA_GBH_NBLKPTRS; g++) 1475 ASSERT(gn->gn_child[g] == NULL); 1476 1477 zio_buf_free(gn->gn_gbh, SPA_GANGBLOCKSIZE); 1478 kmem_free(gn, sizeof (*gn)); 1479 *gnpp = NULL; 1480 } 1481 1482 static void 1483 zio_gang_tree_free(zio_gang_node_t **gnpp) 1484 { 1485 zio_gang_node_t *gn = *gnpp; 1486 1487 if (gn == NULL) 1488 return; 1489 1490 for (int g = 0; g < SPA_GBH_NBLKPTRS; g++) 1491 zio_gang_tree_free(&gn->gn_child[g]); 1492 1493 zio_gang_node_free(gnpp); 1494 } 1495 1496 static void 1497 zio_gang_tree_assemble(zio_t *gio, blkptr_t *bp, zio_gang_node_t **gnpp) 1498 { 1499 zio_gang_node_t *gn = zio_gang_node_alloc(gnpp); 1500 1501 ASSERT(gio->io_gang_leader == gio); 1502 ASSERT(BP_IS_GANG(bp)); 1503 1504 zio_nowait(zio_read(gio, gio->io_spa, bp, gn->gn_gbh, 1505 SPA_GANGBLOCKSIZE, zio_gang_tree_assemble_done, gn, 1506 gio->io_priority, ZIO_GANG_CHILD_FLAGS(gio), &gio->io_bookmark)); 1507 } 1508 1509 static void 1510 zio_gang_tree_assemble_done(zio_t *zio) 1511 { 1512 zio_t *gio = zio->io_gang_leader; 1513 zio_gang_node_t *gn = zio->io_private; 1514 blkptr_t *bp = zio->io_bp; 1515 1516 ASSERT(gio == zio_unique_parent(zio)); 1517 ASSERT(zio->io_child_count == 0); 1518 1519 if (zio->io_error) 1520 return; 1521 1522 if (BP_SHOULD_BYTESWAP(bp)) 1523 byteswap_uint64_array(zio->io_data, zio->io_size); 1524 1525 ASSERT(zio->io_data == gn->gn_gbh); 1526 ASSERT(zio->io_size == SPA_GANGBLOCKSIZE); 1527 ASSERT(gn->gn_gbh->zg_tail.zbt_magic == ZBT_MAGIC); 1528 1529 for (int g = 0; g < SPA_GBH_NBLKPTRS; g++) { 1530 blkptr_t *gbp = &gn->gn_gbh->zg_blkptr[g]; 1531 if (!BP_IS_GANG(gbp)) 1532 continue; 1533 zio_gang_tree_assemble(gio, gbp, &gn->gn_child[g]); 1534 } 1535 } 1536 1537 static void 1538 zio_gang_tree_issue(zio_t *pio, zio_gang_node_t *gn, blkptr_t *bp, void *data) 1539 { 1540 zio_t *gio = pio->io_gang_leader; 1541 zio_t *zio; 1542 1543 ASSERT(BP_IS_GANG(bp) == !!gn); 1544 ASSERT(BP_GET_CHECKSUM(bp) == BP_GET_CHECKSUM(gio->io_bp)); 1545 ASSERT(BP_GET_LSIZE(bp) == BP_GET_PSIZE(bp) || gn == gio->io_gang_tree); 1546 1547 /* 1548 * If you're a gang header, your data is in gn->gn_gbh. 1549 * If you're a gang member, your data is in 'data' and gn == NULL. 1550 */ 1551 zio = zio_gang_issue_func[gio->io_type](pio, bp, gn, data); 1552 1553 if (gn != NULL) { 1554 ASSERT(gn->gn_gbh->zg_tail.zbt_magic == ZBT_MAGIC); 1555 1556 for (int g = 0; g < SPA_GBH_NBLKPTRS; g++) { 1557 blkptr_t *gbp = &gn->gn_gbh->zg_blkptr[g]; 1558 if (BP_IS_HOLE(gbp)) 1559 continue; 1560 zio_gang_tree_issue(zio, gn->gn_child[g], gbp, data); 1561 data = (char *)data + BP_GET_PSIZE(gbp); 1562 } 1563 } 1564 1565 if (gn == gio->io_gang_tree) 1566 ASSERT3P((char *)gio->io_data + gio->io_size, ==, data); 1567 1568 if (zio != pio) 1569 zio_nowait(zio); 1570 } 1571 1572 static int 1573 zio_gang_assemble(zio_t *zio) 1574 { 1575 blkptr_t *bp = zio->io_bp; 1576 1577 ASSERT(BP_IS_GANG(bp) && zio->io_gang_leader == NULL); 1578 ASSERT(zio->io_child_type > ZIO_CHILD_GANG); 1579 1580 zio->io_gang_leader = zio; 1581 1582 zio_gang_tree_assemble(zio, bp, &zio->io_gang_tree); 1583 1584 return (ZIO_PIPELINE_CONTINUE); 1585 } 1586 1587 static int 1588 zio_gang_issue(zio_t *zio) 1589 { 1590 blkptr_t *bp = zio->io_bp; 1591 1592 if (zio_wait_for_children(zio, ZIO_CHILD_GANG, ZIO_WAIT_DONE)) 1593 return (ZIO_PIPELINE_STOP); 1594 1595 ASSERT(BP_IS_GANG(bp) && zio->io_gang_leader == zio); 1596 ASSERT(zio->io_child_type > ZIO_CHILD_GANG); 1597 1598 if (zio->io_child_error[ZIO_CHILD_GANG] == 0) 1599 zio_gang_tree_issue(zio, zio->io_gang_tree, bp, zio->io_data); 1600 else 1601 zio_gang_tree_free(&zio->io_gang_tree); 1602 1603 zio->io_pipeline = ZIO_INTERLOCK_PIPELINE; 1604 1605 return (ZIO_PIPELINE_CONTINUE); 1606 } 1607 1608 static void 1609 zio_write_gang_member_ready(zio_t *zio) 1610 { 1611 zio_t *pio = zio_unique_parent(zio); 1612 zio_t *gio = zio->io_gang_leader; 1613 dva_t *cdva = zio->io_bp->blk_dva; 1614 dva_t *pdva = pio->io_bp->blk_dva; 1615 uint64_t asize; 1616 1617 if (BP_IS_HOLE(zio->io_bp)) 1618 return; 1619 1620 ASSERT(BP_IS_HOLE(&zio->io_bp_orig)); 1621 1622 ASSERT(zio->io_child_type == ZIO_CHILD_GANG); 1623 ASSERT3U(zio->io_prop.zp_copies, ==, gio->io_prop.zp_copies); 1624 ASSERT3U(zio->io_prop.zp_copies, <=, BP_GET_NDVAS(zio->io_bp)); 1625 ASSERT3U(pio->io_prop.zp_copies, <=, BP_GET_NDVAS(pio->io_bp)); 1626 ASSERT3U(BP_GET_NDVAS(zio->io_bp), <=, BP_GET_NDVAS(pio->io_bp)); 1627 1628 mutex_enter(&pio->io_lock); 1629 for (int d = 0; d < BP_GET_NDVAS(zio->io_bp); d++) { 1630 ASSERT(DVA_GET_GANG(&pdva[d])); 1631 asize = DVA_GET_ASIZE(&pdva[d]); 1632 asize += DVA_GET_ASIZE(&cdva[d]); 1633 DVA_SET_ASIZE(&pdva[d], asize); 1634 } 1635 mutex_exit(&pio->io_lock); 1636 } 1637 1638 static int 1639 zio_write_gang_block(zio_t *pio) 1640 { 1641 spa_t *spa = pio->io_spa; 1642 blkptr_t *bp = pio->io_bp; 1643 zio_t *gio = pio->io_gang_leader; 1644 zio_t *zio; 1645 zio_gang_node_t *gn, **gnpp; 1646 zio_gbh_phys_t *gbh; 1647 uint64_t txg = pio->io_txg; 1648 uint64_t resid = pio->io_size; 1649 uint64_t lsize; 1650 int copies = gio->io_prop.zp_copies; 1651 int gbh_copies = MIN(copies + 1, spa_max_replication(spa)); 1652 zio_prop_t zp; 1653 int error; 1654 1655 error = metaslab_alloc(spa, spa_normal_class(spa), SPA_GANGBLOCKSIZE, 1656 bp, gbh_copies, txg, pio == gio ? NULL : gio->io_bp, 1657 METASLAB_HINTBP_FAVOR | METASLAB_GANG_HEADER); 1658 if (error) { 1659 pio->io_error = error; 1660 return (ZIO_PIPELINE_CONTINUE); 1661 } 1662 1663 if (pio == gio) { 1664 gnpp = &gio->io_gang_tree; 1665 } else { 1666 gnpp = pio->io_private; 1667 ASSERT(pio->io_ready == zio_write_gang_member_ready); 1668 } 1669 1670 gn = zio_gang_node_alloc(gnpp); 1671 gbh = gn->gn_gbh; 1672 bzero(gbh, SPA_GANGBLOCKSIZE); 1673 1674 /* 1675 * Create the gang header. 1676 */ 1677 zio = zio_rewrite(pio, spa, txg, bp, gbh, SPA_GANGBLOCKSIZE, NULL, NULL, 1678 pio->io_priority, ZIO_GANG_CHILD_FLAGS(pio), &pio->io_bookmark); 1679 1680 /* 1681 * Create and nowait the gang children. 1682 */ 1683 for (int g = 0; resid != 0; resid -= lsize, g++) { 1684 lsize = P2ROUNDUP(resid / (SPA_GBH_NBLKPTRS - g), 1685 SPA_MINBLOCKSIZE); 1686 ASSERT(lsize >= SPA_MINBLOCKSIZE && lsize <= resid); 1687 1688 zp.zp_checksum = gio->io_prop.zp_checksum; 1689 zp.zp_compress = ZIO_COMPRESS_OFF; 1690 zp.zp_type = DMU_OT_NONE; 1691 zp.zp_level = 0; 1692 zp.zp_copies = gio->io_prop.zp_copies; 1693 zp.zp_dedup = 0; 1694 zp.zp_dedup_verify = 0; 1695 1696 zio_nowait(zio_write(zio, spa, txg, &gbh->zg_blkptr[g], 1697 (char *)pio->io_data + (pio->io_size - resid), lsize, &zp, 1698 zio_write_gang_member_ready, NULL, &gn->gn_child[g], 1699 pio->io_priority, ZIO_GANG_CHILD_FLAGS(pio), 1700 &pio->io_bookmark)); 1701 } 1702 1703 /* 1704 * Set pio's pipeline to just wait for zio to finish. 1705 */ 1706 pio->io_pipeline = ZIO_INTERLOCK_PIPELINE; 1707 1708 zio_nowait(zio); 1709 1710 return (ZIO_PIPELINE_CONTINUE); 1711 } 1712 1713 /* 1714 * ========================================================================== 1715 * Dedup 1716 * ========================================================================== 1717 */ 1718 static void 1719 zio_ddt_child_read_done(zio_t *zio) 1720 { 1721 blkptr_t *bp = zio->io_bp; 1722 ddt_entry_t *dde = zio->io_private; 1723 ddt_phys_t *ddp; 1724 zio_t *pio = zio_unique_parent(zio); 1725 1726 mutex_enter(&pio->io_lock); 1727 ddp = ddt_phys_select(dde, bp); 1728 if (zio->io_error == 0) 1729 ddt_phys_clear(ddp); /* this ddp doesn't need repair */ 1730 if (zio->io_error == 0 && dde->dde_repair_data == NULL) 1731 dde->dde_repair_data = zio->io_data; 1732 else 1733 zio_buf_free(zio->io_data, zio->io_size); 1734 mutex_exit(&pio->io_lock); 1735 } 1736 1737 static int 1738 zio_ddt_read_start(zio_t *zio) 1739 { 1740 blkptr_t *bp = zio->io_bp; 1741 1742 ASSERT(BP_GET_DEDUP(bp)); 1743 ASSERT(BP_GET_PSIZE(bp) == zio->io_size); 1744 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL); 1745 1746 if (zio->io_child_error[ZIO_CHILD_DDT]) { 1747 ddt_t *ddt = ddt_select(zio->io_spa, bp); 1748 ddt_entry_t *dde = ddt_repair_start(ddt, bp); 1749 ddt_phys_t *ddp = dde->dde_phys; 1750 ddt_phys_t *ddp_self = ddt_phys_select(dde, bp); 1751 blkptr_t blk; 1752 1753 ASSERT(zio->io_vsd == NULL); 1754 zio->io_vsd = dde; 1755 1756 if (ddp_self == NULL) 1757 return (ZIO_PIPELINE_CONTINUE); 1758 1759 for (int p = 0; p < DDT_PHYS_TYPES; p++, ddp++) { 1760 if (ddp->ddp_phys_birth == 0 || ddp == ddp_self) 1761 continue; 1762 ddt_bp_create(ddt->ddt_checksum, &dde->dde_key, ddp, 1763 &blk); 1764 zio_nowait(zio_read(zio, zio->io_spa, &blk, 1765 zio_buf_alloc(zio->io_size), zio->io_size, 1766 zio_ddt_child_read_done, dde, zio->io_priority, 1767 ZIO_DDT_CHILD_FLAGS(zio) | ZIO_FLAG_DONT_PROPAGATE, 1768 &zio->io_bookmark)); 1769 } 1770 return (ZIO_PIPELINE_CONTINUE); 1771 } 1772 1773 zio_nowait(zio_read(zio, zio->io_spa, bp, 1774 zio->io_data, zio->io_size, NULL, NULL, zio->io_priority, 1775 ZIO_DDT_CHILD_FLAGS(zio), &zio->io_bookmark)); 1776 1777 return (ZIO_PIPELINE_CONTINUE); 1778 } 1779 1780 static int 1781 zio_ddt_read_done(zio_t *zio) 1782 { 1783 blkptr_t *bp = zio->io_bp; 1784 1785 if (zio_wait_for_children(zio, ZIO_CHILD_DDT, ZIO_WAIT_DONE)) 1786 return (ZIO_PIPELINE_STOP); 1787 1788 ASSERT(BP_GET_DEDUP(bp)); 1789 ASSERT(BP_GET_PSIZE(bp) == zio->io_size); 1790 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL); 1791 1792 if (zio->io_child_error[ZIO_CHILD_DDT]) { 1793 ddt_t *ddt = ddt_select(zio->io_spa, bp); 1794 ddt_entry_t *dde = zio->io_vsd; 1795 if (ddt == NULL) { 1796 ASSERT(spa_load_state(zio->io_spa) != SPA_LOAD_NONE); 1797 return (ZIO_PIPELINE_CONTINUE); 1798 } 1799 if (dde == NULL) { 1800 zio->io_stage = ZIO_STAGE_DDT_READ_START >> 1; 1801 zio_taskq_dispatch(zio, ZIO_TASKQ_ISSUE, B_FALSE); 1802 return (ZIO_PIPELINE_STOP); 1803 } 1804 if (dde->dde_repair_data != NULL) { 1805 bcopy(dde->dde_repair_data, zio->io_data, zio->io_size); 1806 zio->io_child_error[ZIO_CHILD_DDT] = 0; 1807 } 1808 ddt_repair_done(ddt, dde); 1809 zio->io_vsd = NULL; 1810 } 1811 1812 ASSERT(zio->io_vsd == NULL); 1813 1814 return (ZIO_PIPELINE_CONTINUE); 1815 } 1816 1817 static boolean_t 1818 zio_ddt_collision(zio_t *zio, ddt_t *ddt, ddt_entry_t *dde) 1819 { 1820 spa_t *spa = zio->io_spa; 1821 1822 /* 1823 * Note: we compare the original data, not the transformed data, 1824 * because when zio->io_bp is an override bp, we will not have 1825 * pushed the I/O transforms. That's an important optimization 1826 * because otherwise we'd compress/encrypt all dmu_sync() data twice. 1827 */ 1828 for (int p = DDT_PHYS_SINGLE; p <= DDT_PHYS_TRIPLE; p++) { 1829 zio_t *lio = dde->dde_lead_zio[p]; 1830 1831 if (lio != NULL) { 1832 return (lio->io_orig_size != zio->io_orig_size || 1833 bcmp(zio->io_orig_data, lio->io_orig_data, 1834 zio->io_orig_size) != 0); 1835 } 1836 } 1837 1838 for (int p = DDT_PHYS_SINGLE; p <= DDT_PHYS_TRIPLE; p++) { 1839 ddt_phys_t *ddp = &dde->dde_phys[p]; 1840 1841 if (ddp->ddp_phys_birth != 0) { 1842 arc_buf_t *abuf = NULL; 1843 uint32_t aflags = ARC_WAIT; 1844 blkptr_t blk = *zio->io_bp; 1845 int error; 1846 1847 ddt_bp_fill(ddp, &blk, ddp->ddp_phys_birth); 1848 1849 ddt_exit(ddt); 1850 1851 error = arc_read_nolock(NULL, spa, &blk, 1852 arc_getbuf_func, &abuf, ZIO_PRIORITY_SYNC_READ, 1853 ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE, 1854 &aflags, &zio->io_bookmark); 1855 1856 if (error == 0) { 1857 if (arc_buf_size(abuf) != zio->io_orig_size || 1858 bcmp(abuf->b_data, zio->io_orig_data, 1859 zio->io_orig_size) != 0) 1860 error = EEXIST; 1861 VERIFY(arc_buf_remove_ref(abuf, &abuf) == 1); 1862 } 1863 1864 ddt_enter(ddt); 1865 return (error != 0); 1866 } 1867 } 1868 1869 return (B_FALSE); 1870 } 1871 1872 static void 1873 zio_ddt_child_write_ready(zio_t *zio) 1874 { 1875 int p = zio->io_prop.zp_copies; 1876 ddt_t *ddt = ddt_select(zio->io_spa, zio->io_bp); 1877 ddt_entry_t *dde = zio->io_private; 1878 ddt_phys_t *ddp = &dde->dde_phys[p]; 1879 zio_t *pio; 1880 1881 if (zio->io_error) 1882 return; 1883 1884 ddt_enter(ddt); 1885 1886 ASSERT(dde->dde_lead_zio[p] == zio); 1887 1888 ddt_phys_fill(ddp, zio->io_bp); 1889 1890 while ((pio = zio_walk_parents(zio)) != NULL) 1891 ddt_bp_fill(ddp, pio->io_bp, zio->io_txg); 1892 1893 ddt_exit(ddt); 1894 } 1895 1896 static void 1897 zio_ddt_child_write_done(zio_t *zio) 1898 { 1899 int p = zio->io_prop.zp_copies; 1900 ddt_t *ddt = ddt_select(zio->io_spa, zio->io_bp); 1901 ddt_entry_t *dde = zio->io_private; 1902 ddt_phys_t *ddp = &dde->dde_phys[p]; 1903 1904 ddt_enter(ddt); 1905 1906 ASSERT(ddp->ddp_refcnt == 0); 1907 ASSERT(dde->dde_lead_zio[p] == zio); 1908 dde->dde_lead_zio[p] = NULL; 1909 1910 if (zio->io_error == 0) { 1911 while (zio_walk_parents(zio) != NULL) 1912 ddt_phys_addref(ddp); 1913 } else { 1914 ddt_phys_clear(ddp); 1915 } 1916 1917 ddt_exit(ddt); 1918 } 1919 1920 static void 1921 zio_ddt_ditto_write_done(zio_t *zio) 1922 { 1923 int p = DDT_PHYS_DITTO; 1924 zio_prop_t *zp = &zio->io_prop; 1925 blkptr_t *bp = zio->io_bp; 1926 ddt_t *ddt = ddt_select(zio->io_spa, bp); 1927 ddt_entry_t *dde = zio->io_private; 1928 ddt_phys_t *ddp = &dde->dde_phys[p]; 1929 ddt_key_t *ddk = &dde->dde_key; 1930 1931 ddt_enter(ddt); 1932 1933 ASSERT(ddp->ddp_refcnt == 0); 1934 ASSERT(dde->dde_lead_zio[p] == zio); 1935 dde->dde_lead_zio[p] = NULL; 1936 1937 if (zio->io_error == 0) { 1938 ASSERT(ZIO_CHECKSUM_EQUAL(bp->blk_cksum, ddk->ddk_cksum)); 1939 ASSERT(zp->zp_copies < SPA_DVAS_PER_BP); 1940 ASSERT(zp->zp_copies == BP_GET_NDVAS(bp) - BP_IS_GANG(bp)); 1941 if (ddp->ddp_phys_birth != 0) 1942 ddt_phys_free(ddt, ddk, ddp, zio->io_txg); 1943 ddt_phys_fill(ddp, bp); 1944 } 1945 1946 ddt_exit(ddt); 1947 } 1948 1949 static int 1950 zio_ddt_write(zio_t *zio) 1951 { 1952 spa_t *spa = zio->io_spa; 1953 blkptr_t *bp = zio->io_bp; 1954 uint64_t txg = zio->io_txg; 1955 zio_prop_t *zp = &zio->io_prop; 1956 int p = zp->zp_copies; 1957 int ditto_copies; 1958 zio_t *cio = NULL; 1959 zio_t *dio = NULL; 1960 ddt_t *ddt = ddt_select(spa, bp); 1961 ddt_entry_t *dde; 1962 ddt_phys_t *ddp; 1963 1964 ASSERT(BP_GET_DEDUP(bp)); 1965 ASSERT(BP_GET_CHECKSUM(bp) == zp->zp_checksum); 1966 ASSERT(BP_IS_HOLE(bp) || zio->io_bp_override); 1967 1968 ddt_enter(ddt); 1969 dde = ddt_lookup(ddt, bp, B_TRUE); 1970 ddp = &dde->dde_phys[p]; 1971 1972 if (zp->zp_dedup_verify && zio_ddt_collision(zio, ddt, dde)) { 1973 /* 1974 * If we're using a weak checksum, upgrade to a strong checksum 1975 * and try again. If we're already using a strong checksum, 1976 * we can't resolve it, so just convert to an ordinary write. 1977 * (And automatically e-mail a paper to Nature?) 1978 */ 1979 if (!zio_checksum_table[zp->zp_checksum].ci_dedup) { 1980 zp->zp_checksum = spa_dedup_checksum(spa); 1981 zio_pop_transforms(zio); 1982 zio->io_stage = ZIO_STAGE_OPEN; 1983 BP_ZERO(bp); 1984 } else { 1985 zp->zp_dedup = 0; 1986 } 1987 zio->io_pipeline = ZIO_WRITE_PIPELINE; 1988 ddt_exit(ddt); 1989 return (ZIO_PIPELINE_CONTINUE); 1990 } 1991 1992 ditto_copies = ddt_ditto_copies_needed(ddt, dde, ddp); 1993 ASSERT(ditto_copies < SPA_DVAS_PER_BP); 1994 1995 if (ditto_copies > ddt_ditto_copies_present(dde) && 1996 dde->dde_lead_zio[DDT_PHYS_DITTO] == NULL) { 1997 zio_prop_t czp = *zp; 1998 1999 czp.zp_copies = ditto_copies; 2000 2001 /* 2002 * If we arrived here with an override bp, we won't have run 2003 * the transform stack, so we won't have the data we need to 2004 * generate a child i/o. So, toss the override bp and restart. 2005 * This is safe, because using the override bp is just an 2006 * optimization; and it's rare, so the cost doesn't matter. 2007 */ 2008 if (zio->io_bp_override) { 2009 zio_pop_transforms(zio); 2010 zio->io_stage = ZIO_STAGE_OPEN; 2011 zio->io_pipeline = ZIO_WRITE_PIPELINE; 2012 zio->io_bp_override = NULL; 2013 BP_ZERO(bp); 2014 ddt_exit(ddt); 2015 return (ZIO_PIPELINE_CONTINUE); 2016 } 2017 2018 dio = zio_write(zio, spa, txg, bp, zio->io_orig_data, 2019 zio->io_orig_size, &czp, NULL, 2020 zio_ddt_ditto_write_done, dde, zio->io_priority, 2021 ZIO_DDT_CHILD_FLAGS(zio), &zio->io_bookmark); 2022 2023 zio_push_transform(dio, zio->io_data, zio->io_size, 0, NULL); 2024 dde->dde_lead_zio[DDT_PHYS_DITTO] = dio; 2025 } 2026 2027 if (ddp->ddp_phys_birth != 0 || dde->dde_lead_zio[p] != NULL) { 2028 if (ddp->ddp_phys_birth != 0) 2029 ddt_bp_fill(ddp, bp, txg); 2030 if (dde->dde_lead_zio[p] != NULL) 2031 zio_add_child(zio, dde->dde_lead_zio[p]); 2032 else 2033 ddt_phys_addref(ddp); 2034 } else if (zio->io_bp_override) { 2035 ASSERT(bp->blk_birth == txg); 2036 ASSERT(BP_EQUAL(bp, zio->io_bp_override)); 2037 ddt_phys_fill(ddp, bp); 2038 ddt_phys_addref(ddp); 2039 } else { 2040 cio = zio_write(zio, spa, txg, bp, zio->io_orig_data, 2041 zio->io_orig_size, zp, zio_ddt_child_write_ready, 2042 zio_ddt_child_write_done, dde, zio->io_priority, 2043 ZIO_DDT_CHILD_FLAGS(zio), &zio->io_bookmark); 2044 2045 zio_push_transform(cio, zio->io_data, zio->io_size, 0, NULL); 2046 dde->dde_lead_zio[p] = cio; 2047 } 2048 2049 ddt_exit(ddt); 2050 2051 if (cio) 2052 zio_nowait(cio); 2053 if (dio) 2054 zio_nowait(dio); 2055 2056 return (ZIO_PIPELINE_CONTINUE); 2057 } 2058 2059 static int 2060 zio_ddt_free(zio_t *zio) 2061 { 2062 spa_t *spa = zio->io_spa; 2063 blkptr_t *bp = zio->io_bp; 2064 ddt_t *ddt = ddt_select(spa, bp); 2065 ddt_entry_t *dde; 2066 ddt_phys_t *ddp; 2067 2068 ASSERT(BP_GET_DEDUP(bp)); 2069 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL); 2070 2071 ddt_enter(ddt); 2072 dde = ddt_lookup(ddt, bp, B_TRUE); 2073 ddp = ddt_phys_select(dde, bp); 2074 ddt_phys_decref(ddp); 2075 ddt_exit(ddt); 2076 2077 return (ZIO_PIPELINE_CONTINUE); 2078 } 2079 2080 /* 2081 * ========================================================================== 2082 * Allocate and free blocks 2083 * ========================================================================== 2084 */ 2085 static int 2086 zio_dva_allocate(zio_t *zio) 2087 { 2088 spa_t *spa = zio->io_spa; 2089 metaslab_class_t *mc = spa_normal_class(spa); 2090 blkptr_t *bp = zio->io_bp; 2091 int error; 2092 2093 if (zio->io_gang_leader == NULL) { 2094 ASSERT(zio->io_child_type > ZIO_CHILD_GANG); 2095 zio->io_gang_leader = zio; 2096 } 2097 2098 ASSERT(BP_IS_HOLE(bp)); 2099 ASSERT3U(BP_GET_NDVAS(bp), ==, 0); 2100 ASSERT3U(zio->io_prop.zp_copies, >, 0); 2101 ASSERT3U(zio->io_prop.zp_copies, <=, spa_max_replication(spa)); 2102 ASSERT3U(zio->io_size, ==, BP_GET_PSIZE(bp)); 2103 2104 error = metaslab_alloc(spa, mc, zio->io_size, bp, 2105 zio->io_prop.zp_copies, zio->io_txg, NULL, 0); 2106 2107 if (error) { 2108 if (error == ENOSPC && zio->io_size > SPA_MINBLOCKSIZE) 2109 return (zio_write_gang_block(zio)); 2110 zio->io_error = error; 2111 } 2112 2113 return (ZIO_PIPELINE_CONTINUE); 2114 } 2115 2116 static int 2117 zio_dva_free(zio_t *zio) 2118 { 2119 metaslab_free(zio->io_spa, zio->io_bp, zio->io_txg, B_FALSE); 2120 2121 return (ZIO_PIPELINE_CONTINUE); 2122 } 2123 2124 static int 2125 zio_dva_claim(zio_t *zio) 2126 { 2127 int error; 2128 2129 error = metaslab_claim(zio->io_spa, zio->io_bp, zio->io_txg); 2130 if (error) 2131 zio->io_error = error; 2132 2133 return (ZIO_PIPELINE_CONTINUE); 2134 } 2135 2136 /* 2137 * Undo an allocation. This is used by zio_done() when an I/O fails 2138 * and we want to give back the block we just allocated. 2139 * This handles both normal blocks and gang blocks. 2140 */ 2141 static void 2142 zio_dva_unallocate(zio_t *zio, zio_gang_node_t *gn, blkptr_t *bp) 2143 { 2144 ASSERT(bp->blk_birth == zio->io_txg || BP_IS_HOLE(bp)); 2145 ASSERT(zio->io_bp_override == NULL); 2146 2147 if (!BP_IS_HOLE(bp)) 2148 metaslab_free(zio->io_spa, bp, bp->blk_birth, B_TRUE); 2149 2150 if (gn != NULL) { 2151 for (int g = 0; g < SPA_GBH_NBLKPTRS; g++) { 2152 zio_dva_unallocate(zio, gn->gn_child[g], 2153 &gn->gn_gbh->zg_blkptr[g]); 2154 } 2155 } 2156 } 2157 2158 /* 2159 * Try to allocate an intent log block. Return 0 on success, errno on failure. 2160 */ 2161 int 2162 zio_alloc_zil(spa_t *spa, uint64_t txg, blkptr_t *new_bp, blkptr_t *old_bp, 2163 uint64_t size, boolean_t use_slog) 2164 { 2165 int error = 1; 2166 2167 ASSERT(txg > spa_syncing_txg(spa)); 2168 2169 if (use_slog) 2170 error = metaslab_alloc(spa, spa_log_class(spa), size, 2171 new_bp, 1, txg, old_bp, METASLAB_HINTBP_AVOID); 2172 2173 if (error) 2174 error = metaslab_alloc(spa, spa_normal_class(spa), size, 2175 new_bp, 1, txg, old_bp, METASLAB_HINTBP_AVOID); 2176 2177 if (error == 0) { 2178 BP_SET_LSIZE(new_bp, size); 2179 BP_SET_PSIZE(new_bp, size); 2180 BP_SET_COMPRESS(new_bp, ZIO_COMPRESS_OFF); 2181 BP_SET_CHECKSUM(new_bp, ZIO_CHECKSUM_ZILOG); 2182 BP_SET_TYPE(new_bp, DMU_OT_INTENT_LOG); 2183 BP_SET_LEVEL(new_bp, 0); 2184 BP_SET_DEDUP(new_bp, 0); 2185 BP_SET_BYTEORDER(new_bp, ZFS_HOST_BYTEORDER); 2186 } 2187 2188 return (error); 2189 } 2190 2191 /* 2192 * Free an intent log block. 2193 */ 2194 void 2195 zio_free_zil(spa_t *spa, uint64_t txg, blkptr_t *bp) 2196 { 2197 ASSERT(BP_GET_TYPE(bp) == DMU_OT_INTENT_LOG); 2198 ASSERT(!BP_IS_GANG(bp)); 2199 2200 zio_free(spa, txg, bp); 2201 } 2202 2203 /* 2204 * ========================================================================== 2205 * Read and write to physical devices 2206 * ========================================================================== 2207 */ 2208 static int 2209 zio_vdev_io_start(zio_t *zio) 2210 { 2211 vdev_t *vd = zio->io_vd; 2212 uint64_t align; 2213 spa_t *spa = zio->io_spa; 2214 2215 ASSERT(zio->io_error == 0); 2216 ASSERT(zio->io_child_error[ZIO_CHILD_VDEV] == 0); 2217 2218 if (vd == NULL) { 2219 if (!(zio->io_flags & ZIO_FLAG_CONFIG_WRITER)) 2220 spa_config_enter(spa, SCL_ZIO, zio, RW_READER); 2221 2222 /* 2223 * The mirror_ops handle multiple DVAs in a single BP. 2224 */ 2225 return (vdev_mirror_ops.vdev_op_io_start(zio)); 2226 } 2227 2228 align = 1ULL << vd->vdev_top->vdev_ashift; 2229 2230 if (P2PHASE(zio->io_size, align) != 0) { 2231 uint64_t asize = P2ROUNDUP(zio->io_size, align); 2232 char *abuf = zio_buf_alloc(asize); 2233 ASSERT(vd == vd->vdev_top); 2234 if (zio->io_type == ZIO_TYPE_WRITE) { 2235 bcopy(zio->io_data, abuf, zio->io_size); 2236 bzero(abuf + zio->io_size, asize - zio->io_size); 2237 } 2238 zio_push_transform(zio, abuf, asize, asize, zio_subblock); 2239 } 2240 2241 ASSERT(P2PHASE(zio->io_offset, align) == 0); 2242 ASSERT(P2PHASE(zio->io_size, align) == 0); 2243 ASSERT(zio->io_type != ZIO_TYPE_WRITE || spa_writeable(spa)); 2244 2245 /* 2246 * If this is a repair I/O, and there's no self-healing involved -- 2247 * that is, we're just resilvering what we expect to resilver -- 2248 * then don't do the I/O unless zio's txg is actually in vd's DTL. 2249 * This prevents spurious resilvering with nested replication. 2250 * For example, given a mirror of mirrors, (A+B)+(C+D), if only 2251 * A is out of date, we'll read from C+D, then use the data to 2252 * resilver A+B -- but we don't actually want to resilver B, just A. 2253 * The top-level mirror has no way to know this, so instead we just 2254 * discard unnecessary repairs as we work our way down the vdev tree. 2255 * The same logic applies to any form of nested replication: 2256 * ditto + mirror, RAID-Z + replacing, etc. This covers them all. 2257 */ 2258 if ((zio->io_flags & ZIO_FLAG_IO_REPAIR) && 2259 !(zio->io_flags & ZIO_FLAG_SELF_HEAL) && 2260 zio->io_txg != 0 && /* not a delegated i/o */ 2261 !vdev_dtl_contains(vd, DTL_PARTIAL, zio->io_txg, 1)) { 2262 ASSERT(zio->io_type == ZIO_TYPE_WRITE); 2263 zio_vdev_io_bypass(zio); 2264 return (ZIO_PIPELINE_CONTINUE); 2265 } 2266 2267 if (vd->vdev_ops->vdev_op_leaf && 2268 (zio->io_type == ZIO_TYPE_READ || zio->io_type == ZIO_TYPE_WRITE)) { 2269 2270 if (zio->io_type == ZIO_TYPE_READ && vdev_cache_read(zio) == 0) 2271 return (ZIO_PIPELINE_CONTINUE); 2272 2273 if ((zio = vdev_queue_io(zio)) == NULL) 2274 return (ZIO_PIPELINE_STOP); 2275 2276 if (!vdev_accessible(vd, zio)) { 2277 zio->io_error = ENXIO; 2278 zio_interrupt(zio); 2279 return (ZIO_PIPELINE_STOP); 2280 } 2281 } 2282 2283 return (vd->vdev_ops->vdev_op_io_start(zio)); 2284 } 2285 2286 static int 2287 zio_vdev_io_done(zio_t *zio) 2288 { 2289 vdev_t *vd = zio->io_vd; 2290 vdev_ops_t *ops = vd ? vd->vdev_ops : &vdev_mirror_ops; 2291 boolean_t unexpected_error = B_FALSE; 2292 2293 if (zio_wait_for_children(zio, ZIO_CHILD_VDEV, ZIO_WAIT_DONE)) 2294 return (ZIO_PIPELINE_STOP); 2295 2296 ASSERT(zio->io_type == ZIO_TYPE_READ || zio->io_type == ZIO_TYPE_WRITE); 2297 2298 if (vd != NULL && vd->vdev_ops->vdev_op_leaf) { 2299 2300 vdev_queue_io_done(zio); 2301 2302 if (zio->io_type == ZIO_TYPE_WRITE) 2303 vdev_cache_write(zio); 2304 2305 if (zio_injection_enabled && zio->io_error == 0) 2306 zio->io_error = zio_handle_device_injection(vd, 2307 zio, EIO); 2308 2309 if (zio_injection_enabled && zio->io_error == 0) 2310 zio->io_error = zio_handle_label_injection(zio, EIO); 2311 2312 if (zio->io_error) { 2313 if (!vdev_accessible(vd, zio)) { 2314 zio->io_error = ENXIO; 2315 } else { 2316 unexpected_error = B_TRUE; 2317 } 2318 } 2319 } 2320 2321 ops->vdev_op_io_done(zio); 2322 2323 if (unexpected_error) 2324 VERIFY(vdev_probe(vd, zio) == NULL); 2325 2326 return (ZIO_PIPELINE_CONTINUE); 2327 } 2328 2329 /* 2330 * For non-raidz ZIOs, we can just copy aside the bad data read from the 2331 * disk, and use that to finish the checksum ereport later. 2332 */ 2333 static void 2334 zio_vsd_default_cksum_finish(zio_cksum_report_t *zcr, 2335 const void *good_buf) 2336 { 2337 /* no processing needed */ 2338 zfs_ereport_finish_checksum(zcr, good_buf, zcr->zcr_cbdata, B_FALSE); 2339 } 2340 2341 /*ARGSUSED*/ 2342 void 2343 zio_vsd_default_cksum_report(zio_t *zio, zio_cksum_report_t *zcr, void *ignored) 2344 { 2345 void *buf = zio_buf_alloc(zio->io_size); 2346 2347 bcopy(zio->io_data, buf, zio->io_size); 2348 2349 zcr->zcr_cbinfo = zio->io_size; 2350 zcr->zcr_cbdata = buf; 2351 zcr->zcr_finish = zio_vsd_default_cksum_finish; 2352 zcr->zcr_free = zio_buf_free; 2353 } 2354 2355 static int 2356 zio_vdev_io_assess(zio_t *zio) 2357 { 2358 vdev_t *vd = zio->io_vd; 2359 2360 if (zio_wait_for_children(zio, ZIO_CHILD_VDEV, ZIO_WAIT_DONE)) 2361 return (ZIO_PIPELINE_STOP); 2362 2363 if (vd == NULL && !(zio->io_flags & ZIO_FLAG_CONFIG_WRITER)) 2364 spa_config_exit(zio->io_spa, SCL_ZIO, zio); 2365 2366 if (zio->io_vsd != NULL) { 2367 zio->io_vsd_ops->vsd_free(zio); 2368 zio->io_vsd = NULL; 2369 } 2370 2371 if (zio_injection_enabled && zio->io_error == 0) 2372 zio->io_error = zio_handle_fault_injection(zio, EIO); 2373 2374 /* 2375 * If the I/O failed, determine whether we should attempt to retry it. 2376 * 2377 * On retry, we cut in line in the issue queue, since we don't want 2378 * compression/checksumming/etc. work to prevent our (cheap) IO reissue. 2379 */ 2380 if (zio->io_error && vd == NULL && 2381 !(zio->io_flags & (ZIO_FLAG_DONT_RETRY | ZIO_FLAG_IO_RETRY))) { 2382 ASSERT(!(zio->io_flags & ZIO_FLAG_DONT_QUEUE)); /* not a leaf */ 2383 ASSERT(!(zio->io_flags & ZIO_FLAG_IO_BYPASS)); /* not a leaf */ 2384 zio->io_error = 0; 2385 zio->io_flags |= ZIO_FLAG_IO_RETRY | 2386 ZIO_FLAG_DONT_CACHE | ZIO_FLAG_DONT_AGGREGATE; 2387 zio->io_stage = ZIO_STAGE_VDEV_IO_START >> 1; 2388 zio_taskq_dispatch(zio, ZIO_TASKQ_ISSUE, 2389 zio_requeue_io_start_cut_in_line); 2390 return (ZIO_PIPELINE_STOP); 2391 } 2392 2393 /* 2394 * If we got an error on a leaf device, convert it to ENXIO 2395 * if the device is not accessible at all. 2396 */ 2397 if (zio->io_error && vd != NULL && vd->vdev_ops->vdev_op_leaf && 2398 !vdev_accessible(vd, zio)) 2399 zio->io_error = ENXIO; 2400 2401 /* 2402 * If we can't write to an interior vdev (mirror or RAID-Z), 2403 * set vdev_cant_write so that we stop trying to allocate from it. 2404 */ 2405 if (zio->io_error == ENXIO && zio->io_type == ZIO_TYPE_WRITE && 2406 vd != NULL && !vd->vdev_ops->vdev_op_leaf) 2407 vd->vdev_cant_write = B_TRUE; 2408 2409 if (zio->io_error) 2410 zio->io_pipeline = ZIO_INTERLOCK_PIPELINE; 2411 2412 return (ZIO_PIPELINE_CONTINUE); 2413 } 2414 2415 void 2416 zio_vdev_io_reissue(zio_t *zio) 2417 { 2418 ASSERT(zio->io_stage == ZIO_STAGE_VDEV_IO_START); 2419 ASSERT(zio->io_error == 0); 2420 2421 zio->io_stage >>= 1; 2422 } 2423 2424 void 2425 zio_vdev_io_redone(zio_t *zio) 2426 { 2427 ASSERT(zio->io_stage == ZIO_STAGE_VDEV_IO_DONE); 2428 2429 zio->io_stage >>= 1; 2430 } 2431 2432 void 2433 zio_vdev_io_bypass(zio_t *zio) 2434 { 2435 ASSERT(zio->io_stage == ZIO_STAGE_VDEV_IO_START); 2436 ASSERT(zio->io_error == 0); 2437 2438 zio->io_flags |= ZIO_FLAG_IO_BYPASS; 2439 zio->io_stage = ZIO_STAGE_VDEV_IO_ASSESS >> 1; 2440 } 2441 2442 /* 2443 * ========================================================================== 2444 * Generate and verify checksums 2445 * ========================================================================== 2446 */ 2447 static int 2448 zio_checksum_generate(zio_t *zio) 2449 { 2450 blkptr_t *bp = zio->io_bp; 2451 enum zio_checksum checksum; 2452 2453 if (bp == NULL) { 2454 /* 2455 * This is zio_write_phys(). 2456 * We're either generating a label checksum, or none at all. 2457 */ 2458 checksum = zio->io_prop.zp_checksum; 2459 2460 if (checksum == ZIO_CHECKSUM_OFF) 2461 return (ZIO_PIPELINE_CONTINUE); 2462 2463 ASSERT(checksum == ZIO_CHECKSUM_LABEL); 2464 } else { 2465 if (BP_IS_GANG(bp) && zio->io_child_type == ZIO_CHILD_GANG) { 2466 ASSERT(!IO_IS_ALLOCATING(zio)); 2467 checksum = ZIO_CHECKSUM_GANG_HEADER; 2468 } else { 2469 checksum = BP_GET_CHECKSUM(bp); 2470 } 2471 } 2472 2473 zio_checksum_compute(zio, checksum, zio->io_data, zio->io_size); 2474 2475 return (ZIO_PIPELINE_CONTINUE); 2476 } 2477 2478 static int 2479 zio_checksum_verify(zio_t *zio) 2480 { 2481 zio_bad_cksum_t info; 2482 blkptr_t *bp = zio->io_bp; 2483 int error; 2484 2485 ASSERT(zio->io_vd != NULL); 2486 2487 if (bp == NULL) { 2488 /* 2489 * This is zio_read_phys(). 2490 * We're either verifying a label checksum, or nothing at all. 2491 */ 2492 if (zio->io_prop.zp_checksum == ZIO_CHECKSUM_OFF) 2493 return (ZIO_PIPELINE_CONTINUE); 2494 2495 ASSERT(zio->io_prop.zp_checksum == ZIO_CHECKSUM_LABEL); 2496 } 2497 2498 if ((error = zio_checksum_error(zio, &info)) != 0) { 2499 zio->io_error = error; 2500 if (!(zio->io_flags & ZIO_FLAG_SPECULATIVE)) { 2501 zfs_ereport_start_checksum(zio->io_spa, 2502 zio->io_vd, zio, zio->io_offset, 2503 zio->io_size, NULL, &info); 2504 } 2505 } 2506 2507 return (ZIO_PIPELINE_CONTINUE); 2508 } 2509 2510 /* 2511 * Called by RAID-Z to ensure we don't compute the checksum twice. 2512 */ 2513 void 2514 zio_checksum_verified(zio_t *zio) 2515 { 2516 zio->io_pipeline &= ~ZIO_STAGE_CHECKSUM_VERIFY; 2517 } 2518 2519 /* 2520 * ========================================================================== 2521 * Error rank. Error are ranked in the order 0, ENXIO, ECKSUM, EIO, other. 2522 * An error of 0 indictes success. ENXIO indicates whole-device failure, 2523 * which may be transient (e.g. unplugged) or permament. ECKSUM and EIO 2524 * indicate errors that are specific to one I/O, and most likely permanent. 2525 * Any other error is presumed to be worse because we weren't expecting it. 2526 * ========================================================================== 2527 */ 2528 int 2529 zio_worst_error(int e1, int e2) 2530 { 2531 static int zio_error_rank[] = { 0, ENXIO, ECKSUM, EIO }; 2532 int r1, r2; 2533 2534 for (r1 = 0; r1 < sizeof (zio_error_rank) / sizeof (int); r1++) 2535 if (e1 == zio_error_rank[r1]) 2536 break; 2537 2538 for (r2 = 0; r2 < sizeof (zio_error_rank) / sizeof (int); r2++) 2539 if (e2 == zio_error_rank[r2]) 2540 break; 2541 2542 return (r1 > r2 ? e1 : e2); 2543 } 2544 2545 /* 2546 * ========================================================================== 2547 * I/O completion 2548 * ========================================================================== 2549 */ 2550 static int 2551 zio_ready(zio_t *zio) 2552 { 2553 blkptr_t *bp = zio->io_bp; 2554 zio_t *pio, *pio_next; 2555 2556 if (zio_wait_for_children(zio, ZIO_CHILD_GANG, ZIO_WAIT_READY) || 2557 zio_wait_for_children(zio, ZIO_CHILD_DDT, ZIO_WAIT_READY)) 2558 return (ZIO_PIPELINE_STOP); 2559 2560 if (zio->io_ready) { 2561 ASSERT(IO_IS_ALLOCATING(zio)); 2562 ASSERT(bp->blk_birth == zio->io_txg || BP_IS_HOLE(bp)); 2563 ASSERT(zio->io_children[ZIO_CHILD_GANG][ZIO_WAIT_READY] == 0); 2564 2565 zio->io_ready(zio); 2566 } 2567 2568 if (bp != NULL && bp != &zio->io_bp_copy) 2569 zio->io_bp_copy = *bp; 2570 2571 if (zio->io_error) 2572 zio->io_pipeline = ZIO_INTERLOCK_PIPELINE; 2573 2574 mutex_enter(&zio->io_lock); 2575 zio->io_state[ZIO_WAIT_READY] = 1; 2576 pio = zio_walk_parents(zio); 2577 mutex_exit(&zio->io_lock); 2578 2579 /* 2580 * As we notify zio's parents, new parents could be added. 2581 * New parents go to the head of zio's io_parent_list, however, 2582 * so we will (correctly) not notify them. The remainder of zio's 2583 * io_parent_list, from 'pio_next' onward, cannot change because 2584 * all parents must wait for us to be done before they can be done. 2585 */ 2586 for (; pio != NULL; pio = pio_next) { 2587 pio_next = zio_walk_parents(zio); 2588 zio_notify_parent(pio, zio, ZIO_WAIT_READY); 2589 } 2590 2591 if (zio->io_flags & ZIO_FLAG_NODATA) { 2592 if (BP_IS_GANG(bp)) { 2593 zio->io_flags &= ~ZIO_FLAG_NODATA; 2594 } else { 2595 ASSERT((uintptr_t)zio->io_data < SPA_MAXBLOCKSIZE); 2596 zio->io_pipeline &= ~ZIO_VDEV_IO_STAGES; 2597 } 2598 } 2599 2600 if (zio_injection_enabled && 2601 zio->io_spa->spa_syncing_txg == zio->io_txg) 2602 zio_handle_ignored_writes(zio); 2603 2604 return (ZIO_PIPELINE_CONTINUE); 2605 } 2606 2607 static int 2608 zio_done(zio_t *zio) 2609 { 2610 spa_t *spa = zio->io_spa; 2611 zio_t *lio = zio->io_logical; 2612 blkptr_t *bp = zio->io_bp; 2613 vdev_t *vd = zio->io_vd; 2614 uint64_t psize = zio->io_size; 2615 zio_t *pio, *pio_next; 2616 2617 /* 2618 * If our children haven't all completed, 2619 * wait for them and then repeat this pipeline stage. 2620 */ 2621 if (zio_wait_for_children(zio, ZIO_CHILD_VDEV, ZIO_WAIT_DONE) || 2622 zio_wait_for_children(zio, ZIO_CHILD_GANG, ZIO_WAIT_DONE) || 2623 zio_wait_for_children(zio, ZIO_CHILD_DDT, ZIO_WAIT_DONE) || 2624 zio_wait_for_children(zio, ZIO_CHILD_LOGICAL, ZIO_WAIT_DONE)) 2625 return (ZIO_PIPELINE_STOP); 2626 2627 for (int c = 0; c < ZIO_CHILD_TYPES; c++) 2628 for (int w = 0; w < ZIO_WAIT_TYPES; w++) 2629 ASSERT(zio->io_children[c][w] == 0); 2630 2631 if (bp != NULL) { 2632 ASSERT(bp->blk_pad[0] == 0); 2633 ASSERT(bp->blk_pad[1] == 0); 2634 ASSERT(bcmp(bp, &zio->io_bp_copy, sizeof (blkptr_t)) == 0 || 2635 (bp == zio_unique_parent(zio)->io_bp)); 2636 if (zio->io_type == ZIO_TYPE_WRITE && !BP_IS_HOLE(bp) && 2637 zio->io_bp_override == NULL && 2638 !(zio->io_flags & ZIO_FLAG_IO_REPAIR)) { 2639 ASSERT(!BP_SHOULD_BYTESWAP(bp)); 2640 ASSERT3U(zio->io_prop.zp_copies, <=, BP_GET_NDVAS(bp)); 2641 ASSERT(BP_COUNT_GANG(bp) == 0 || 2642 (BP_COUNT_GANG(bp) == BP_GET_NDVAS(bp))); 2643 } 2644 } 2645 2646 /* 2647 * If there were child vdev/gang/ddt errors, they apply to us now. 2648 */ 2649 zio_inherit_child_errors(zio, ZIO_CHILD_VDEV); 2650 zio_inherit_child_errors(zio, ZIO_CHILD_GANG); 2651 zio_inherit_child_errors(zio, ZIO_CHILD_DDT); 2652 2653 /* 2654 * If the I/O on the transformed data was successful, generate any 2655 * checksum reports now while we still have the transformed data. 2656 */ 2657 if (zio->io_error == 0) { 2658 while (zio->io_cksum_report != NULL) { 2659 zio_cksum_report_t *zcr = zio->io_cksum_report; 2660 uint64_t align = zcr->zcr_align; 2661 uint64_t asize = P2ROUNDUP(psize, align); 2662 char *abuf = zio->io_data; 2663 2664 if (asize != psize) { 2665 abuf = zio_buf_alloc(asize); 2666 bcopy(zio->io_data, abuf, psize); 2667 bzero(abuf + psize, asize - psize); 2668 } 2669 2670 zio->io_cksum_report = zcr->zcr_next; 2671 zcr->zcr_next = NULL; 2672 zcr->zcr_finish(zcr, abuf); 2673 zfs_ereport_free_checksum(zcr); 2674 2675 if (asize != psize) 2676 zio_buf_free(abuf, asize); 2677 } 2678 } 2679 2680 zio_pop_transforms(zio); /* note: may set zio->io_error */ 2681 2682 vdev_stat_update(zio, psize); 2683 2684 if (zio->io_error) { 2685 /* 2686 * If this I/O is attached to a particular vdev, 2687 * generate an error message describing the I/O failure 2688 * at the block level. We ignore these errors if the 2689 * device is currently unavailable. 2690 */ 2691 if (zio->io_error != ECKSUM && vd != NULL && !vdev_is_dead(vd)) 2692 zfs_ereport_post(FM_EREPORT_ZFS_IO, spa, vd, zio, 0, 0); 2693 2694 if ((zio->io_error == EIO || !(zio->io_flags & 2695 (ZIO_FLAG_SPECULATIVE | ZIO_FLAG_DONT_PROPAGATE))) && 2696 zio == lio) { 2697 /* 2698 * For logical I/O requests, tell the SPA to log the 2699 * error and generate a logical data ereport. 2700 */ 2701 spa_log_error(spa, zio); 2702 zfs_ereport_post(FM_EREPORT_ZFS_DATA, spa, NULL, zio, 2703 0, 0); 2704 } 2705 } 2706 2707 if (zio->io_error && zio == lio) { 2708 /* 2709 * Determine whether zio should be reexecuted. This will 2710 * propagate all the way to the root via zio_notify_parent(). 2711 */ 2712 ASSERT(vd == NULL && bp != NULL); 2713 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL); 2714 2715 if (IO_IS_ALLOCATING(zio) && 2716 !(zio->io_flags & ZIO_FLAG_CANFAIL)) { 2717 if (zio->io_error != ENOSPC) 2718 zio->io_reexecute |= ZIO_REEXECUTE_NOW; 2719 else 2720 zio->io_reexecute |= ZIO_REEXECUTE_SUSPEND; 2721 } 2722 2723 if ((zio->io_type == ZIO_TYPE_READ || 2724 zio->io_type == ZIO_TYPE_FREE) && 2725 zio->io_error == ENXIO && 2726 spa_load_state(spa) == SPA_LOAD_NONE && 2727 spa_get_failmode(spa) != ZIO_FAILURE_MODE_CONTINUE) 2728 zio->io_reexecute |= ZIO_REEXECUTE_SUSPEND; 2729 2730 if (!(zio->io_flags & ZIO_FLAG_CANFAIL) && !zio->io_reexecute) 2731 zio->io_reexecute |= ZIO_REEXECUTE_SUSPEND; 2732 2733 /* 2734 * Here is a possibly good place to attempt to do 2735 * either combinatorial reconstruction or error correction 2736 * based on checksums. It also might be a good place 2737 * to send out preliminary ereports before we suspend 2738 * processing. 2739 */ 2740 } 2741 2742 /* 2743 * If there were logical child errors, they apply to us now. 2744 * We defer this until now to avoid conflating logical child 2745 * errors with errors that happened to the zio itself when 2746 * updating vdev stats and reporting FMA events above. 2747 */ 2748 zio_inherit_child_errors(zio, ZIO_CHILD_LOGICAL); 2749 2750 if ((zio->io_error || zio->io_reexecute) && 2751 IO_IS_ALLOCATING(zio) && zio->io_gang_leader == zio && 2752 !(zio->io_flags & ZIO_FLAG_IO_REWRITE)) 2753 zio_dva_unallocate(zio, zio->io_gang_tree, bp); 2754 2755 zio_gang_tree_free(&zio->io_gang_tree); 2756 2757 /* 2758 * Godfather I/Os should never suspend. 2759 */ 2760 if ((zio->io_flags & ZIO_FLAG_GODFATHER) && 2761 (zio->io_reexecute & ZIO_REEXECUTE_SUSPEND)) 2762 zio->io_reexecute = 0; 2763 2764 if (zio->io_reexecute) { 2765 /* 2766 * This is a logical I/O that wants to reexecute. 2767 * 2768 * Reexecute is top-down. When an i/o fails, if it's not 2769 * the root, it simply notifies its parent and sticks around. 2770 * The parent, seeing that it still has children in zio_done(), 2771 * does the same. This percolates all the way up to the root. 2772 * The root i/o will reexecute or suspend the entire tree. 2773 * 2774 * This approach ensures that zio_reexecute() honors 2775 * all the original i/o dependency relationships, e.g. 2776 * parents not executing until children are ready. 2777 */ 2778 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL); 2779 2780 zio->io_gang_leader = NULL; 2781 2782 mutex_enter(&zio->io_lock); 2783 zio->io_state[ZIO_WAIT_DONE] = 1; 2784 mutex_exit(&zio->io_lock); 2785 2786 /* 2787 * "The Godfather" I/O monitors its children but is 2788 * not a true parent to them. It will track them through 2789 * the pipeline but severs its ties whenever they get into 2790 * trouble (e.g. suspended). This allows "The Godfather" 2791 * I/O to return status without blocking. 2792 */ 2793 for (pio = zio_walk_parents(zio); pio != NULL; pio = pio_next) { 2794 zio_link_t *zl = zio->io_walk_link; 2795 pio_next = zio_walk_parents(zio); 2796 2797 if ((pio->io_flags & ZIO_FLAG_GODFATHER) && 2798 (zio->io_reexecute & ZIO_REEXECUTE_SUSPEND)) { 2799 zio_remove_child(pio, zio, zl); 2800 zio_notify_parent(pio, zio, ZIO_WAIT_DONE); 2801 } 2802 } 2803 2804 if ((pio = zio_unique_parent(zio)) != NULL) { 2805 /* 2806 * We're not a root i/o, so there's nothing to do 2807 * but notify our parent. Don't propagate errors 2808 * upward since we haven't permanently failed yet. 2809 */ 2810 ASSERT(!(zio->io_flags & ZIO_FLAG_GODFATHER)); 2811 zio->io_flags |= ZIO_FLAG_DONT_PROPAGATE; 2812 zio_notify_parent(pio, zio, ZIO_WAIT_DONE); 2813 } else if (zio->io_reexecute & ZIO_REEXECUTE_SUSPEND) { 2814 /* 2815 * We'd fail again if we reexecuted now, so suspend 2816 * until conditions improve (e.g. device comes online). 2817 */ 2818 zio_suspend(spa, zio); 2819 } else { 2820 /* 2821 * Reexecution is potentially a huge amount of work. 2822 * Hand it off to the otherwise-unused claim taskq. 2823 */ 2824 (void) taskq_dispatch( 2825 spa->spa_zio_taskq[ZIO_TYPE_CLAIM][ZIO_TASKQ_ISSUE], 2826 (task_func_t *)zio_reexecute, zio, TQ_SLEEP); 2827 } 2828 return (ZIO_PIPELINE_STOP); 2829 } 2830 2831 ASSERT(zio->io_child_count == 0); 2832 ASSERT(zio->io_reexecute == 0); 2833 ASSERT(zio->io_error == 0 || (zio->io_flags & ZIO_FLAG_CANFAIL)); 2834 2835 /* 2836 * Report any checksum errors, since the I/O is complete. 2837 */ 2838 while (zio->io_cksum_report != NULL) { 2839 zio_cksum_report_t *zcr = zio->io_cksum_report; 2840 zio->io_cksum_report = zcr->zcr_next; 2841 zcr->zcr_next = NULL; 2842 zcr->zcr_finish(zcr, NULL); 2843 zfs_ereport_free_checksum(zcr); 2844 } 2845 2846 /* 2847 * It is the responsibility of the done callback to ensure that this 2848 * particular zio is no longer discoverable for adoption, and as 2849 * such, cannot acquire any new parents. 2850 */ 2851 if (zio->io_done) 2852 zio->io_done(zio); 2853 2854 mutex_enter(&zio->io_lock); 2855 zio->io_state[ZIO_WAIT_DONE] = 1; 2856 mutex_exit(&zio->io_lock); 2857 2858 for (pio = zio_walk_parents(zio); pio != NULL; pio = pio_next) { 2859 zio_link_t *zl = zio->io_walk_link; 2860 pio_next = zio_walk_parents(zio); 2861 zio_remove_child(pio, zio, zl); 2862 zio_notify_parent(pio, zio, ZIO_WAIT_DONE); 2863 } 2864 2865 if (zio->io_waiter != NULL) { 2866 mutex_enter(&zio->io_lock); 2867 zio->io_executor = NULL; 2868 cv_broadcast(&zio->io_cv); 2869 mutex_exit(&zio->io_lock); 2870 } else { 2871 zio_destroy(zio); 2872 } 2873 2874 return (ZIO_PIPELINE_STOP); 2875 } 2876 2877 /* 2878 * ========================================================================== 2879 * I/O pipeline definition 2880 * ========================================================================== 2881 */ 2882 static zio_pipe_stage_t *zio_pipeline[] = { 2883 NULL, 2884 zio_read_bp_init, 2885 zio_free_bp_init, 2886 zio_issue_async, 2887 zio_write_bp_init, 2888 zio_checksum_generate, 2889 zio_ddt_read_start, 2890 zio_ddt_read_done, 2891 zio_ddt_write, 2892 zio_ddt_free, 2893 zio_gang_assemble, 2894 zio_gang_issue, 2895 zio_dva_allocate, 2896 zio_dva_free, 2897 zio_dva_claim, 2898 zio_ready, 2899 zio_vdev_io_start, 2900 zio_vdev_io_done, 2901 zio_vdev_io_assess, 2902 zio_checksum_verify, 2903 zio_done 2904 }; 2905