zio.c revision 320496
1/* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21/* 22 * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved. 23 * Copyright (c) 2011, 2016 by Delphix. All rights reserved. 24 * Copyright (c) 2011 Nexenta Systems, Inc. All rights reserved. 25 * Copyright (c) 2014 Integros [integros.com] 26 */ 27 28#include <sys/sysmacros.h> 29#include <sys/zfs_context.h> 30#include <sys/fm/fs/zfs.h> 31#include <sys/spa.h> 32#include <sys/txg.h> 33#include <sys/spa_impl.h> 34#include <sys/vdev_impl.h> 35#include <sys/zio_impl.h> 36#include <sys/zio_compress.h> 37#include <sys/zio_checksum.h> 38#include <sys/dmu_objset.h> 39#include <sys/arc.h> 40#include <sys/ddt.h> 41#include <sys/trim_map.h> 42#include <sys/blkptr.h> 43#include <sys/zfeature.h> 44#include <sys/metaslab_impl.h> 45 46SYSCTL_DECL(_vfs_zfs); 47SYSCTL_NODE(_vfs_zfs, OID_AUTO, zio, CTLFLAG_RW, 0, "ZFS ZIO"); 48#if defined(__amd64__) 49static int zio_use_uma = 1; 50#else 51static int zio_use_uma = 0; 52#endif 53TUNABLE_INT("vfs.zfs.zio.use_uma", &zio_use_uma); 54SYSCTL_INT(_vfs_zfs_zio, OID_AUTO, use_uma, CTLFLAG_RDTUN, &zio_use_uma, 0, 55 "Use uma(9) for ZIO allocations"); 56static int zio_exclude_metadata = 0; 57TUNABLE_INT("vfs.zfs.zio.exclude_metadata", &zio_exclude_metadata); 58SYSCTL_INT(_vfs_zfs_zio, OID_AUTO, exclude_metadata, CTLFLAG_RDTUN, &zio_exclude_metadata, 0, 59 "Exclude metadata buffers from dumps as well"); 60 61zio_trim_stats_t zio_trim_stats = { 62 { "bytes", KSTAT_DATA_UINT64, 63 "Number of bytes successfully TRIMmed" }, 64 { "success", KSTAT_DATA_UINT64, 65 "Number of successful TRIM requests" }, 66 { "unsupported", KSTAT_DATA_UINT64, 67 "Number of TRIM requests that failed because TRIM is not supported" }, 68 { "failed", KSTAT_DATA_UINT64, 69 "Number of TRIM requests that failed for reasons other than not supported" }, 70}; 71 72static kstat_t *zio_trim_ksp; 73 74/* 75 * ========================================================================== 76 * I/O type descriptions 77 * ========================================================================== 78 */ 79const char *zio_type_name[ZIO_TYPES] = { 80 "zio_null", "zio_read", "zio_write", "zio_free", "zio_claim", 81 "zio_ioctl" 82}; 83 84boolean_t zio_dva_throttle_enabled = B_TRUE; 85SYSCTL_INT(_vfs_zfs_zio, OID_AUTO, dva_throttle_enabled, CTLFLAG_RDTUN, 86 &zio_dva_throttle_enabled, 0, ""); 87 88/* 89 * ========================================================================== 90 * I/O kmem caches 91 * ========================================================================== 92 */ 93kmem_cache_t *zio_cache; 94kmem_cache_t *zio_link_cache; 95kmem_cache_t *zio_buf_cache[SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT]; 96kmem_cache_t *zio_data_buf_cache[SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT]; 97 98#ifdef _KERNEL 99extern vmem_t *zio_alloc_arena; 100#endif 101 102#define ZIO_PIPELINE_CONTINUE 0x100 103#define ZIO_PIPELINE_STOP 0x101 104 105#define BP_SPANB(indblkshift, level) \ 106 (((uint64_t)1) << ((level) * ((indblkshift) - SPA_BLKPTRSHIFT))) 107#define COMPARE_META_LEVEL 0x80000000ul 108/* 109 * The following actions directly effect the spa's sync-to-convergence logic. 110 * The values below define the sync pass when we start performing the action. 111 * Care should be taken when changing these values as they directly impact 112 * spa_sync() performance. Tuning these values may introduce subtle performance 113 * pathologies and should only be done in the context of performance analysis. 114 * These tunables will eventually be removed and replaced with #defines once 115 * enough analysis has been done to determine optimal values. 116 * 117 * The 'zfs_sync_pass_deferred_free' pass must be greater than 1 to ensure that 118 * regular blocks are not deferred. 119 */ 120int zfs_sync_pass_deferred_free = 2; /* defer frees starting in this pass */ 121TUNABLE_INT("vfs.zfs.sync_pass_deferred_free", &zfs_sync_pass_deferred_free); 122SYSCTL_INT(_vfs_zfs, OID_AUTO, sync_pass_deferred_free, CTLFLAG_RDTUN, 123 &zfs_sync_pass_deferred_free, 0, "defer frees starting in this pass"); 124int zfs_sync_pass_dont_compress = 5; /* don't compress starting in this pass */ 125TUNABLE_INT("vfs.zfs.sync_pass_dont_compress", &zfs_sync_pass_dont_compress); 126SYSCTL_INT(_vfs_zfs, OID_AUTO, sync_pass_dont_compress, CTLFLAG_RDTUN, 127 &zfs_sync_pass_dont_compress, 0, "don't compress starting in this pass"); 128int zfs_sync_pass_rewrite = 2; /* rewrite new bps starting in this pass */ 129TUNABLE_INT("vfs.zfs.sync_pass_rewrite", &zfs_sync_pass_rewrite); 130SYSCTL_INT(_vfs_zfs, OID_AUTO, sync_pass_rewrite, CTLFLAG_RDTUN, 131 &zfs_sync_pass_rewrite, 0, "rewrite new bps starting in this pass"); 132 133/* 134 * An allocating zio is one that either currently has the DVA allocate 135 * stage set or will have it later in its lifetime. 136 */ 137#define IO_IS_ALLOCATING(zio) ((zio)->io_orig_pipeline & ZIO_STAGE_DVA_ALLOCATE) 138 139boolean_t zio_requeue_io_start_cut_in_line = B_TRUE; 140 141#ifdef illumos 142#ifdef ZFS_DEBUG 143int zio_buf_debug_limit = 16384; 144#else 145int zio_buf_debug_limit = 0; 146#endif 147#endif 148 149static void zio_taskq_dispatch(zio_t *, zio_taskq_type_t, boolean_t); 150 151void 152zio_init(void) 153{ 154 size_t c; 155 zio_cache = kmem_cache_create("zio_cache", 156 sizeof (zio_t), 0, NULL, NULL, NULL, NULL, NULL, 0); 157 zio_link_cache = kmem_cache_create("zio_link_cache", 158 sizeof (zio_link_t), 0, NULL, NULL, NULL, NULL, NULL, 0); 159 if (!zio_use_uma) 160 goto out; 161 162 /* 163 * For small buffers, we want a cache for each multiple of 164 * SPA_MINBLOCKSIZE. For larger buffers, we want a cache 165 * for each quarter-power of 2. 166 */ 167 for (c = 0; c < SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT; c++) { 168 size_t size = (c + 1) << SPA_MINBLOCKSHIFT; 169 size_t p2 = size; 170 size_t align = 0; 171 int cflags = zio_exclude_metadata ? KMC_NODEBUG : 0; 172 173 while (!ISP2(p2)) 174 p2 &= p2 - 1; 175 176#ifdef illumos 177#ifndef _KERNEL 178 /* 179 * If we are using watchpoints, put each buffer on its own page, 180 * to eliminate the performance overhead of trapping to the 181 * kernel when modifying a non-watched buffer that shares the 182 * page with a watched buffer. 183 */ 184 if (arc_watch && !IS_P2ALIGNED(size, PAGESIZE)) 185 continue; 186#endif 187#endif /* illumos */ 188 if (size <= 4 * SPA_MINBLOCKSIZE) { 189 align = SPA_MINBLOCKSIZE; 190 } else if (IS_P2ALIGNED(size, p2 >> 2)) { 191 align = MIN(p2 >> 2, PAGESIZE); 192 } 193 194 if (align != 0) { 195 char name[36]; 196 (void) sprintf(name, "zio_buf_%lu", (ulong_t)size); 197 zio_buf_cache[c] = kmem_cache_create(name, size, 198 align, NULL, NULL, NULL, NULL, NULL, cflags); 199 200 /* 201 * Since zio_data bufs do not appear in crash dumps, we 202 * pass KMC_NOTOUCH so that no allocator metadata is 203 * stored with the buffers. 204 */ 205 (void) sprintf(name, "zio_data_buf_%lu", (ulong_t)size); 206 zio_data_buf_cache[c] = kmem_cache_create(name, size, 207 align, NULL, NULL, NULL, NULL, NULL, 208 cflags | KMC_NOTOUCH | KMC_NODEBUG); 209 } 210 } 211 212 while (--c != 0) { 213 ASSERT(zio_buf_cache[c] != NULL); 214 if (zio_buf_cache[c - 1] == NULL) 215 zio_buf_cache[c - 1] = zio_buf_cache[c]; 216 217 ASSERT(zio_data_buf_cache[c] != NULL); 218 if (zio_data_buf_cache[c - 1] == NULL) 219 zio_data_buf_cache[c - 1] = zio_data_buf_cache[c]; 220 } 221out: 222 223 zio_inject_init(); 224 225 zio_trim_ksp = kstat_create("zfs", 0, "zio_trim", "misc", 226 KSTAT_TYPE_NAMED, 227 sizeof(zio_trim_stats) / sizeof(kstat_named_t), 228 KSTAT_FLAG_VIRTUAL); 229 230 if (zio_trim_ksp != NULL) { 231 zio_trim_ksp->ks_data = &zio_trim_stats; 232 kstat_install(zio_trim_ksp); 233 } 234} 235 236void 237zio_fini(void) 238{ 239 size_t c; 240 kmem_cache_t *last_cache = NULL; 241 kmem_cache_t *last_data_cache = NULL; 242 243 for (c = 0; c < SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT; c++) { 244 if (zio_buf_cache[c] != last_cache) { 245 last_cache = zio_buf_cache[c]; 246 kmem_cache_destroy(zio_buf_cache[c]); 247 } 248 zio_buf_cache[c] = NULL; 249 250 if (zio_data_buf_cache[c] != last_data_cache) { 251 last_data_cache = zio_data_buf_cache[c]; 252 kmem_cache_destroy(zio_data_buf_cache[c]); 253 } 254 zio_data_buf_cache[c] = NULL; 255 } 256 257 kmem_cache_destroy(zio_link_cache); 258 kmem_cache_destroy(zio_cache); 259 260 zio_inject_fini(); 261 262 if (zio_trim_ksp != NULL) { 263 kstat_delete(zio_trim_ksp); 264 zio_trim_ksp = NULL; 265 } 266} 267 268/* 269 * ========================================================================== 270 * Allocate and free I/O buffers 271 * ========================================================================== 272 */ 273 274/* 275 * Use zio_buf_alloc to allocate ZFS metadata. This data will appear in a 276 * crashdump if the kernel panics, so use it judiciously. Obviously, it's 277 * useful to inspect ZFS metadata, but if possible, we should avoid keeping 278 * excess / transient data in-core during a crashdump. 279 */ 280static void * 281zio_buf_alloc_impl(size_t size, boolean_t canwait) 282{ 283 size_t c = (size - 1) >> SPA_MINBLOCKSHIFT; 284 int flags = zio_exclude_metadata ? KM_NODEBUG : 0; 285 286 VERIFY3U(c, <, SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT); 287 288 if (zio_use_uma) { 289 return (kmem_cache_alloc(zio_buf_cache[c], 290 canwait ? KM_PUSHPAGE : KM_NOSLEEP)); 291 } else { 292 return (kmem_alloc(size, 293 (canwait ? KM_SLEEP : KM_NOSLEEP) | flags)); 294 } 295} 296 297void * 298zio_buf_alloc(size_t size) 299{ 300 return (zio_buf_alloc_impl(size, B_TRUE)); 301} 302 303void * 304zio_buf_alloc_nowait(size_t size) 305{ 306 return (zio_buf_alloc_impl(size, B_FALSE)); 307} 308 309/* 310 * Use zio_data_buf_alloc to allocate data. The data will not appear in a 311 * crashdump if the kernel panics. This exists so that we will limit the amount 312 * of ZFS data that shows up in a kernel crashdump. (Thus reducing the amount 313 * of kernel heap dumped to disk when the kernel panics) 314 */ 315void * 316zio_data_buf_alloc(size_t size) 317{ 318 size_t c = (size - 1) >> SPA_MINBLOCKSHIFT; 319 320 VERIFY3U(c, <, SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT); 321 322 if (zio_use_uma) 323 return (kmem_cache_alloc(zio_data_buf_cache[c], KM_PUSHPAGE)); 324 else 325 return (kmem_alloc(size, KM_SLEEP | KM_NODEBUG)); 326} 327 328void 329zio_buf_free(void *buf, size_t size) 330{ 331 size_t c = (size - 1) >> SPA_MINBLOCKSHIFT; 332 333 VERIFY3U(c, <, SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT); 334 335 if (zio_use_uma) 336 kmem_cache_free(zio_buf_cache[c], buf); 337 else 338 kmem_free(buf, size); 339} 340 341void 342zio_data_buf_free(void *buf, size_t size) 343{ 344 size_t c = (size - 1) >> SPA_MINBLOCKSHIFT; 345 346 VERIFY3U(c, <, SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT); 347 348 if (zio_use_uma) 349 kmem_cache_free(zio_data_buf_cache[c], buf); 350 else 351 kmem_free(buf, size); 352} 353 354/* 355 * ========================================================================== 356 * Push and pop I/O transform buffers 357 * ========================================================================== 358 */ 359void 360zio_push_transform(zio_t *zio, void *data, uint64_t size, uint64_t bufsize, 361 zio_transform_func_t *transform) 362{ 363 zio_transform_t *zt = kmem_alloc(sizeof (zio_transform_t), KM_SLEEP); 364 365 zt->zt_orig_data = zio->io_data; 366 zt->zt_orig_size = zio->io_size; 367 zt->zt_bufsize = bufsize; 368 zt->zt_transform = transform; 369 370 zt->zt_next = zio->io_transform_stack; 371 zio->io_transform_stack = zt; 372 373 zio->io_data = data; 374 zio->io_size = size; 375} 376 377void 378zio_pop_transforms(zio_t *zio) 379{ 380 zio_transform_t *zt; 381 382 while ((zt = zio->io_transform_stack) != NULL) { 383 if (zt->zt_transform != NULL) 384 zt->zt_transform(zio, 385 zt->zt_orig_data, zt->zt_orig_size); 386 387 if (zt->zt_bufsize != 0) 388 zio_buf_free(zio->io_data, zt->zt_bufsize); 389 390 zio->io_data = zt->zt_orig_data; 391 zio->io_size = zt->zt_orig_size; 392 zio->io_transform_stack = zt->zt_next; 393 394 kmem_free(zt, sizeof (zio_transform_t)); 395 } 396} 397 398/* 399 * ========================================================================== 400 * I/O transform callbacks for subblocks and decompression 401 * ========================================================================== 402 */ 403static void 404zio_subblock(zio_t *zio, void *data, uint64_t size) 405{ 406 ASSERT(zio->io_size > size); 407 408 if (zio->io_type == ZIO_TYPE_READ) 409 bcopy(zio->io_data, data, size); 410} 411 412static void 413zio_decompress(zio_t *zio, void *data, uint64_t size) 414{ 415 if (zio->io_error == 0 && 416 zio_decompress_data(BP_GET_COMPRESS(zio->io_bp), 417 zio->io_data, data, zio->io_size, size) != 0) 418 zio->io_error = SET_ERROR(EIO); 419} 420 421/* 422 * ========================================================================== 423 * I/O parent/child relationships and pipeline interlocks 424 * ========================================================================== 425 */ 426zio_t * 427zio_walk_parents(zio_t *cio, zio_link_t **zl) 428{ 429 list_t *pl = &cio->io_parent_list; 430 431 *zl = (*zl == NULL) ? list_head(pl) : list_next(pl, *zl); 432 if (*zl == NULL) 433 return (NULL); 434 435 ASSERT((*zl)->zl_child == cio); 436 return ((*zl)->zl_parent); 437} 438 439zio_t * 440zio_walk_children(zio_t *pio, zio_link_t **zl) 441{ 442 list_t *cl = &pio->io_child_list; 443 444 *zl = (*zl == NULL) ? list_head(cl) : list_next(cl, *zl); 445 if (*zl == NULL) 446 return (NULL); 447 448 ASSERT((*zl)->zl_parent == pio); 449 return ((*zl)->zl_child); 450} 451 452zio_t * 453zio_unique_parent(zio_t *cio) 454{ 455 zio_link_t *zl = NULL; 456 zio_t *pio = zio_walk_parents(cio, &zl); 457 458 VERIFY3P(zio_walk_parents(cio, &zl), ==, NULL); 459 return (pio); 460} 461 462void 463zio_add_child(zio_t *pio, zio_t *cio) 464{ 465 zio_link_t *zl = kmem_cache_alloc(zio_link_cache, KM_SLEEP); 466 467 /* 468 * Logical I/Os can have logical, gang, or vdev children. 469 * Gang I/Os can have gang or vdev children. 470 * Vdev I/Os can only have vdev children. 471 * The following ASSERT captures all of these constraints. 472 */ 473 ASSERT(cio->io_child_type <= pio->io_child_type); 474 475 zl->zl_parent = pio; 476 zl->zl_child = cio; 477 478 mutex_enter(&cio->io_lock); 479 mutex_enter(&pio->io_lock); 480 481 ASSERT(pio->io_state[ZIO_WAIT_DONE] == 0); 482 483 for (int w = 0; w < ZIO_WAIT_TYPES; w++) 484 pio->io_children[cio->io_child_type][w] += !cio->io_state[w]; 485 486 list_insert_head(&pio->io_child_list, zl); 487 list_insert_head(&cio->io_parent_list, zl); 488 489 pio->io_child_count++; 490 cio->io_parent_count++; 491 492 mutex_exit(&pio->io_lock); 493 mutex_exit(&cio->io_lock); 494} 495 496static void 497zio_remove_child(zio_t *pio, zio_t *cio, zio_link_t *zl) 498{ 499 ASSERT(zl->zl_parent == pio); 500 ASSERT(zl->zl_child == cio); 501 502 mutex_enter(&cio->io_lock); 503 mutex_enter(&pio->io_lock); 504 505 list_remove(&pio->io_child_list, zl); 506 list_remove(&cio->io_parent_list, zl); 507 508 pio->io_child_count--; 509 cio->io_parent_count--; 510 511 mutex_exit(&pio->io_lock); 512 mutex_exit(&cio->io_lock); 513 514 kmem_cache_free(zio_link_cache, zl); 515} 516 517static boolean_t 518zio_wait_for_children(zio_t *zio, enum zio_child child, enum zio_wait_type wait) 519{ 520 uint64_t *countp = &zio->io_children[child][wait]; 521 boolean_t waiting = B_FALSE; 522 523 mutex_enter(&zio->io_lock); 524 ASSERT(zio->io_stall == NULL); 525 if (*countp != 0) { 526 zio->io_stage >>= 1; 527 ASSERT3U(zio->io_stage, !=, ZIO_STAGE_OPEN); 528 zio->io_stall = countp; 529 waiting = B_TRUE; 530 } 531 mutex_exit(&zio->io_lock); 532 533 return (waiting); 534} 535 536static void 537zio_notify_parent(zio_t *pio, zio_t *zio, enum zio_wait_type wait) 538{ 539 uint64_t *countp = &pio->io_children[zio->io_child_type][wait]; 540 int *errorp = &pio->io_child_error[zio->io_child_type]; 541 542 mutex_enter(&pio->io_lock); 543 if (zio->io_error && !(zio->io_flags & ZIO_FLAG_DONT_PROPAGATE)) 544 *errorp = zio_worst_error(*errorp, zio->io_error); 545 pio->io_reexecute |= zio->io_reexecute; 546 ASSERT3U(*countp, >, 0); 547 548 (*countp)--; 549 550 if (*countp == 0 && pio->io_stall == countp) { 551 zio_taskq_type_t type = 552 pio->io_stage < ZIO_STAGE_VDEV_IO_START ? ZIO_TASKQ_ISSUE : 553 ZIO_TASKQ_INTERRUPT; 554 pio->io_stall = NULL; 555 mutex_exit(&pio->io_lock); 556 /* 557 * Dispatch the parent zio in its own taskq so that 558 * the child can continue to make progress. This also 559 * prevents overflowing the stack when we have deeply nested 560 * parent-child relationships. 561 */ 562 zio_taskq_dispatch(pio, type, B_FALSE); 563 } else { 564 mutex_exit(&pio->io_lock); 565 } 566} 567 568static void 569zio_inherit_child_errors(zio_t *zio, enum zio_child c) 570{ 571 if (zio->io_child_error[c] != 0 && zio->io_error == 0) 572 zio->io_error = zio->io_child_error[c]; 573} 574 575int 576zio_timestamp_compare(const void *x1, const void *x2) 577{ 578 const zio_t *z1 = x1; 579 const zio_t *z2 = x2; 580 581 if (z1->io_queued_timestamp < z2->io_queued_timestamp) 582 return (-1); 583 if (z1->io_queued_timestamp > z2->io_queued_timestamp) 584 return (1); 585 586 if (z1->io_bookmark.zb_objset < z2->io_bookmark.zb_objset) 587 return (-1); 588 if (z1->io_bookmark.zb_objset > z2->io_bookmark.zb_objset) 589 return (1); 590 591 if (z1->io_bookmark.zb_object < z2->io_bookmark.zb_object) 592 return (-1); 593 if (z1->io_bookmark.zb_object > z2->io_bookmark.zb_object) 594 return (1); 595 596 if (z1->io_bookmark.zb_level < z2->io_bookmark.zb_level) 597 return (-1); 598 if (z1->io_bookmark.zb_level > z2->io_bookmark.zb_level) 599 return (1); 600 601 if (z1->io_bookmark.zb_blkid < z2->io_bookmark.zb_blkid) 602 return (-1); 603 if (z1->io_bookmark.zb_blkid > z2->io_bookmark.zb_blkid) 604 return (1); 605 606 if (z1 < z2) 607 return (-1); 608 if (z1 > z2) 609 return (1); 610 611 return (0); 612} 613 614/* 615 * ========================================================================== 616 * Create the various types of I/O (read, write, free, etc) 617 * ========================================================================== 618 */ 619static zio_t * 620zio_create(zio_t *pio, spa_t *spa, uint64_t txg, const blkptr_t *bp, 621 void *data, uint64_t size, zio_done_func_t *done, void *private, 622 zio_type_t type, zio_priority_t priority, enum zio_flag flags, 623 vdev_t *vd, uint64_t offset, const zbookmark_phys_t *zb, 624 enum zio_stage stage, enum zio_stage pipeline) 625{ 626 zio_t *zio; 627 628 ASSERT3U(type == ZIO_TYPE_FREE || size, <=, SPA_MAXBLOCKSIZE); 629 ASSERT(P2PHASE(size, SPA_MINBLOCKSIZE) == 0); 630 ASSERT(P2PHASE(offset, SPA_MINBLOCKSIZE) == 0); 631 632 ASSERT(!vd || spa_config_held(spa, SCL_STATE_ALL, RW_READER)); 633 ASSERT(!bp || !(flags & ZIO_FLAG_CONFIG_WRITER)); 634 ASSERT(vd || stage == ZIO_STAGE_OPEN); 635 636 zio = kmem_cache_alloc(zio_cache, KM_SLEEP); 637 bzero(zio, sizeof (zio_t)); 638 639 mutex_init(&zio->io_lock, NULL, MUTEX_DEFAULT, NULL); 640 cv_init(&zio->io_cv, NULL, CV_DEFAULT, NULL); 641 642 list_create(&zio->io_parent_list, sizeof (zio_link_t), 643 offsetof(zio_link_t, zl_parent_node)); 644 list_create(&zio->io_child_list, sizeof (zio_link_t), 645 offsetof(zio_link_t, zl_child_node)); 646 647 if (vd != NULL) 648 zio->io_child_type = ZIO_CHILD_VDEV; 649 else if (flags & ZIO_FLAG_GANG_CHILD) 650 zio->io_child_type = ZIO_CHILD_GANG; 651 else if (flags & ZIO_FLAG_DDT_CHILD) 652 zio->io_child_type = ZIO_CHILD_DDT; 653 else 654 zio->io_child_type = ZIO_CHILD_LOGICAL; 655 656 if (bp != NULL) { 657 zio->io_bp = (blkptr_t *)bp; 658 zio->io_bp_copy = *bp; 659 zio->io_bp_orig = *bp; 660 if (type != ZIO_TYPE_WRITE || 661 zio->io_child_type == ZIO_CHILD_DDT) 662 zio->io_bp = &zio->io_bp_copy; /* so caller can free */ 663 if (zio->io_child_type == ZIO_CHILD_LOGICAL) 664 zio->io_logical = zio; 665 if (zio->io_child_type > ZIO_CHILD_GANG && BP_IS_GANG(bp)) 666 pipeline |= ZIO_GANG_STAGES; 667 } 668 669 zio->io_spa = spa; 670 zio->io_txg = txg; 671 zio->io_done = done; 672 zio->io_private = private; 673 zio->io_type = type; 674 zio->io_priority = priority; 675 zio->io_vd = vd; 676 zio->io_offset = offset; 677 zio->io_orig_data = zio->io_data = data; 678 zio->io_orig_size = zio->io_size = size; 679 zio->io_orig_flags = zio->io_flags = flags; 680 zio->io_orig_stage = zio->io_stage = stage; 681 zio->io_orig_pipeline = zio->io_pipeline = pipeline; 682 zio->io_pipeline_trace = ZIO_STAGE_OPEN; 683 684 zio->io_state[ZIO_WAIT_READY] = (stage >= ZIO_STAGE_READY); 685 zio->io_state[ZIO_WAIT_DONE] = (stage >= ZIO_STAGE_DONE); 686 687 if (zb != NULL) 688 zio->io_bookmark = *zb; 689 690 if (pio != NULL) { 691 if (zio->io_logical == NULL) 692 zio->io_logical = pio->io_logical; 693 if (zio->io_child_type == ZIO_CHILD_GANG) 694 zio->io_gang_leader = pio->io_gang_leader; 695 zio_add_child(pio, zio); 696 } 697 698 return (zio); 699} 700 701static void 702zio_destroy(zio_t *zio) 703{ 704 list_destroy(&zio->io_parent_list); 705 list_destroy(&zio->io_child_list); 706 mutex_destroy(&zio->io_lock); 707 cv_destroy(&zio->io_cv); 708 kmem_cache_free(zio_cache, zio); 709} 710 711zio_t * 712zio_null(zio_t *pio, spa_t *spa, vdev_t *vd, zio_done_func_t *done, 713 void *private, enum zio_flag flags) 714{ 715 zio_t *zio; 716 717 zio = zio_create(pio, spa, 0, NULL, NULL, 0, done, private, 718 ZIO_TYPE_NULL, ZIO_PRIORITY_NOW, flags, vd, 0, NULL, 719 ZIO_STAGE_OPEN, ZIO_INTERLOCK_PIPELINE); 720 721 return (zio); 722} 723 724zio_t * 725zio_root(spa_t *spa, zio_done_func_t *done, void *private, enum zio_flag flags) 726{ 727 return (zio_null(NULL, spa, NULL, done, private, flags)); 728} 729 730void 731zfs_blkptr_verify(spa_t *spa, const blkptr_t *bp) 732{ 733 if (!DMU_OT_IS_VALID(BP_GET_TYPE(bp))) { 734 zfs_panic_recover("blkptr at %p has invalid TYPE %llu", 735 bp, (longlong_t)BP_GET_TYPE(bp)); 736 } 737 if (BP_GET_CHECKSUM(bp) >= ZIO_CHECKSUM_FUNCTIONS || 738 BP_GET_CHECKSUM(bp) <= ZIO_CHECKSUM_ON) { 739 zfs_panic_recover("blkptr at %p has invalid CHECKSUM %llu", 740 bp, (longlong_t)BP_GET_CHECKSUM(bp)); 741 } 742 if (BP_GET_COMPRESS(bp) >= ZIO_COMPRESS_FUNCTIONS || 743 BP_GET_COMPRESS(bp) <= ZIO_COMPRESS_ON) { 744 zfs_panic_recover("blkptr at %p has invalid COMPRESS %llu", 745 bp, (longlong_t)BP_GET_COMPRESS(bp)); 746 } 747 if (BP_GET_LSIZE(bp) > SPA_MAXBLOCKSIZE) { 748 zfs_panic_recover("blkptr at %p has invalid LSIZE %llu", 749 bp, (longlong_t)BP_GET_LSIZE(bp)); 750 } 751 if (BP_GET_PSIZE(bp) > SPA_MAXBLOCKSIZE) { 752 zfs_panic_recover("blkptr at %p has invalid PSIZE %llu", 753 bp, (longlong_t)BP_GET_PSIZE(bp)); 754 } 755 756 if (BP_IS_EMBEDDED(bp)) { 757 if (BPE_GET_ETYPE(bp) > NUM_BP_EMBEDDED_TYPES) { 758 zfs_panic_recover("blkptr at %p has invalid ETYPE %llu", 759 bp, (longlong_t)BPE_GET_ETYPE(bp)); 760 } 761 } 762 763 /* 764 * Pool-specific checks. 765 * 766 * Note: it would be nice to verify that the blk_birth and 767 * BP_PHYSICAL_BIRTH() are not too large. However, spa_freeze() 768 * allows the birth time of log blocks (and dmu_sync()-ed blocks 769 * that are in the log) to be arbitrarily large. 770 */ 771 for (int i = 0; i < BP_GET_NDVAS(bp); i++) { 772 uint64_t vdevid = DVA_GET_VDEV(&bp->blk_dva[i]); 773 if (vdevid >= spa->spa_root_vdev->vdev_children) { 774 zfs_panic_recover("blkptr at %p DVA %u has invalid " 775 "VDEV %llu", 776 bp, i, (longlong_t)vdevid); 777 continue; 778 } 779 vdev_t *vd = spa->spa_root_vdev->vdev_child[vdevid]; 780 if (vd == NULL) { 781 zfs_panic_recover("blkptr at %p DVA %u has invalid " 782 "VDEV %llu", 783 bp, i, (longlong_t)vdevid); 784 continue; 785 } 786 if (vd->vdev_ops == &vdev_hole_ops) { 787 zfs_panic_recover("blkptr at %p DVA %u has hole " 788 "VDEV %llu", 789 bp, i, (longlong_t)vdevid); 790 continue; 791 } 792 if (vd->vdev_ops == &vdev_missing_ops) { 793 /* 794 * "missing" vdevs are valid during import, but we 795 * don't have their detailed info (e.g. asize), so 796 * we can't perform any more checks on them. 797 */ 798 continue; 799 } 800 uint64_t offset = DVA_GET_OFFSET(&bp->blk_dva[i]); 801 uint64_t asize = DVA_GET_ASIZE(&bp->blk_dva[i]); 802 if (BP_IS_GANG(bp)) 803 asize = vdev_psize_to_asize(vd, SPA_GANGBLOCKSIZE); 804 if (offset + asize > vd->vdev_asize) { 805 zfs_panic_recover("blkptr at %p DVA %u has invalid " 806 "OFFSET %llu", 807 bp, i, (longlong_t)offset); 808 } 809 } 810} 811 812zio_t * 813zio_read(zio_t *pio, spa_t *spa, const blkptr_t *bp, 814 void *data, uint64_t size, zio_done_func_t *done, void *private, 815 zio_priority_t priority, enum zio_flag flags, const zbookmark_phys_t *zb) 816{ 817 zio_t *zio; 818 819 zfs_blkptr_verify(spa, bp); 820 821 zio = zio_create(pio, spa, BP_PHYSICAL_BIRTH(bp), bp, 822 data, size, done, private, 823 ZIO_TYPE_READ, priority, flags, NULL, 0, zb, 824 ZIO_STAGE_OPEN, (flags & ZIO_FLAG_DDT_CHILD) ? 825 ZIO_DDT_CHILD_READ_PIPELINE : ZIO_READ_PIPELINE); 826 827 return (zio); 828} 829 830zio_t * 831zio_write(zio_t *pio, spa_t *spa, uint64_t txg, blkptr_t *bp, 832 void *data, uint64_t size, const zio_prop_t *zp, 833 zio_done_func_t *ready, zio_done_func_t *children_ready, 834 zio_done_func_t *physdone, zio_done_func_t *done, 835 void *private, zio_priority_t priority, enum zio_flag flags, 836 const zbookmark_phys_t *zb) 837{ 838 zio_t *zio; 839 840 ASSERT(zp->zp_checksum >= ZIO_CHECKSUM_OFF && 841 zp->zp_checksum < ZIO_CHECKSUM_FUNCTIONS && 842 zp->zp_compress >= ZIO_COMPRESS_OFF && 843 zp->zp_compress < ZIO_COMPRESS_FUNCTIONS && 844 DMU_OT_IS_VALID(zp->zp_type) && 845 zp->zp_level < 32 && 846 zp->zp_copies > 0 && 847 zp->zp_copies <= spa_max_replication(spa)); 848 849 zio = zio_create(pio, spa, txg, bp, data, size, done, private, 850 ZIO_TYPE_WRITE, priority, flags, NULL, 0, zb, 851 ZIO_STAGE_OPEN, (flags & ZIO_FLAG_DDT_CHILD) ? 852 ZIO_DDT_CHILD_WRITE_PIPELINE : ZIO_WRITE_PIPELINE); 853 854 zio->io_ready = ready; 855 zio->io_children_ready = children_ready; 856 zio->io_physdone = physdone; 857 zio->io_prop = *zp; 858 859 /* 860 * Data can be NULL if we are going to call zio_write_override() to 861 * provide the already-allocated BP. But we may need the data to 862 * verify a dedup hit (if requested). In this case, don't try to 863 * dedup (just take the already-allocated BP verbatim). 864 */ 865 if (data == NULL && zio->io_prop.zp_dedup_verify) { 866 zio->io_prop.zp_dedup = zio->io_prop.zp_dedup_verify = B_FALSE; 867 } 868 869 return (zio); 870} 871 872zio_t * 873zio_rewrite(zio_t *pio, spa_t *spa, uint64_t txg, blkptr_t *bp, void *data, 874 uint64_t size, zio_done_func_t *done, void *private, 875 zio_priority_t priority, enum zio_flag flags, zbookmark_phys_t *zb) 876{ 877 zio_t *zio; 878 879 zio = zio_create(pio, spa, txg, bp, data, size, done, private, 880 ZIO_TYPE_WRITE, priority, flags | ZIO_FLAG_IO_REWRITE, NULL, 0, zb, 881 ZIO_STAGE_OPEN, ZIO_REWRITE_PIPELINE); 882 883 return (zio); 884} 885 886void 887zio_write_override(zio_t *zio, blkptr_t *bp, int copies, boolean_t nopwrite) 888{ 889 ASSERT(zio->io_type == ZIO_TYPE_WRITE); 890 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL); 891 ASSERT(zio->io_stage == ZIO_STAGE_OPEN); 892 ASSERT(zio->io_txg == spa_syncing_txg(zio->io_spa)); 893 894 /* 895 * We must reset the io_prop to match the values that existed 896 * when the bp was first written by dmu_sync() keeping in mind 897 * that nopwrite and dedup are mutually exclusive. 898 */ 899 zio->io_prop.zp_dedup = nopwrite ? B_FALSE : zio->io_prop.zp_dedup; 900 zio->io_prop.zp_nopwrite = nopwrite; 901 zio->io_prop.zp_copies = copies; 902 zio->io_bp_override = bp; 903} 904 905void 906zio_free(spa_t *spa, uint64_t txg, const blkptr_t *bp) 907{ 908 909 /* 910 * The check for EMBEDDED is a performance optimization. We 911 * process the free here (by ignoring it) rather than 912 * putting it on the list and then processing it in zio_free_sync(). 913 */ 914 if (BP_IS_EMBEDDED(bp)) 915 return; 916 metaslab_check_free(spa, bp); 917 918 /* 919 * Frees that are for the currently-syncing txg, are not going to be 920 * deferred, and which will not need to do a read (i.e. not GANG or 921 * DEDUP), can be processed immediately. Otherwise, put them on the 922 * in-memory list for later processing. 923 */ 924 if (zfs_trim_enabled || BP_IS_GANG(bp) || BP_GET_DEDUP(bp) || 925 txg != spa->spa_syncing_txg || 926 spa_sync_pass(spa) >= zfs_sync_pass_deferred_free) { 927 bplist_append(&spa->spa_free_bplist[txg & TXG_MASK], bp); 928 } else { 929 VERIFY0(zio_wait(zio_free_sync(NULL, spa, txg, bp, 930 BP_GET_PSIZE(bp), 0))); 931 } 932} 933 934zio_t * 935zio_free_sync(zio_t *pio, spa_t *spa, uint64_t txg, const blkptr_t *bp, 936 uint64_t size, enum zio_flag flags) 937{ 938 zio_t *zio; 939 enum zio_stage stage = ZIO_FREE_PIPELINE; 940 941 ASSERT(!BP_IS_HOLE(bp)); 942 ASSERT(spa_syncing_txg(spa) == txg); 943 ASSERT(spa_sync_pass(spa) < zfs_sync_pass_deferred_free); 944 945 if (BP_IS_EMBEDDED(bp)) 946 return (zio_null(pio, spa, NULL, NULL, NULL, 0)); 947 948 metaslab_check_free(spa, bp); 949 arc_freed(spa, bp); 950 951 if (zfs_trim_enabled) 952 stage |= ZIO_STAGE_ISSUE_ASYNC | ZIO_STAGE_VDEV_IO_START | 953 ZIO_STAGE_VDEV_IO_ASSESS; 954 /* 955 * GANG and DEDUP blocks can induce a read (for the gang block header, 956 * or the DDT), so issue them asynchronously so that this thread is 957 * not tied up. 958 */ 959 else if (BP_IS_GANG(bp) || BP_GET_DEDUP(bp)) 960 stage |= ZIO_STAGE_ISSUE_ASYNC; 961 962 flags |= ZIO_FLAG_DONT_QUEUE; 963 964 zio = zio_create(pio, spa, txg, bp, NULL, size, 965 NULL, NULL, ZIO_TYPE_FREE, ZIO_PRIORITY_NOW, flags, 966 NULL, 0, NULL, ZIO_STAGE_OPEN, stage); 967 968 return (zio); 969} 970 971zio_t * 972zio_claim(zio_t *pio, spa_t *spa, uint64_t txg, const blkptr_t *bp, 973 zio_done_func_t *done, void *private, enum zio_flag flags) 974{ 975 zio_t *zio; 976 977 dprintf_bp(bp, "claiming in txg %llu", txg); 978 979 if (BP_IS_EMBEDDED(bp)) 980 return (zio_null(pio, spa, NULL, NULL, NULL, 0)); 981 982 /* 983 * A claim is an allocation of a specific block. Claims are needed 984 * to support immediate writes in the intent log. The issue is that 985 * immediate writes contain committed data, but in a txg that was 986 * *not* committed. Upon opening the pool after an unclean shutdown, 987 * the intent log claims all blocks that contain immediate write data 988 * so that the SPA knows they're in use. 989 * 990 * All claims *must* be resolved in the first txg -- before the SPA 991 * starts allocating blocks -- so that nothing is allocated twice. 992 * If txg == 0 we just verify that the block is claimable. 993 */ 994 ASSERT3U(spa->spa_uberblock.ub_rootbp.blk_birth, <, spa_first_txg(spa)); 995 ASSERT(txg == spa_first_txg(spa) || txg == 0); 996 ASSERT(!BP_GET_DEDUP(bp) || !spa_writeable(spa)); /* zdb(1M) */ 997 998 zio = zio_create(pio, spa, txg, bp, NULL, BP_GET_PSIZE(bp), 999 done, private, ZIO_TYPE_CLAIM, ZIO_PRIORITY_NOW, flags, 1000 NULL, 0, NULL, ZIO_STAGE_OPEN, ZIO_CLAIM_PIPELINE); 1001 ASSERT0(zio->io_queued_timestamp); 1002 1003 return (zio); 1004} 1005 1006zio_t * 1007zio_ioctl(zio_t *pio, spa_t *spa, vdev_t *vd, int cmd, uint64_t offset, 1008 uint64_t size, zio_done_func_t *done, void *private, 1009 zio_priority_t priority, enum zio_flag flags) 1010{ 1011 zio_t *zio; 1012 int c; 1013 1014 if (vd->vdev_children == 0) { 1015 zio = zio_create(pio, spa, 0, NULL, NULL, size, done, private, 1016 ZIO_TYPE_IOCTL, priority, flags, vd, offset, NULL, 1017 ZIO_STAGE_OPEN, ZIO_IOCTL_PIPELINE); 1018 1019 zio->io_cmd = cmd; 1020 } else { 1021 zio = zio_null(pio, spa, NULL, NULL, NULL, flags); 1022 1023 for (c = 0; c < vd->vdev_children; c++) 1024 zio_nowait(zio_ioctl(zio, spa, vd->vdev_child[c], cmd, 1025 offset, size, done, private, priority, flags)); 1026 } 1027 1028 return (zio); 1029} 1030 1031zio_t * 1032zio_read_phys(zio_t *pio, vdev_t *vd, uint64_t offset, uint64_t size, 1033 void *data, int checksum, zio_done_func_t *done, void *private, 1034 zio_priority_t priority, enum zio_flag flags, boolean_t labels) 1035{ 1036 zio_t *zio; 1037 1038 ASSERT(vd->vdev_children == 0); 1039 ASSERT(!labels || offset + size <= VDEV_LABEL_START_SIZE || 1040 offset >= vd->vdev_psize - VDEV_LABEL_END_SIZE); 1041 ASSERT3U(offset + size, <=, vd->vdev_psize); 1042 1043 zio = zio_create(pio, vd->vdev_spa, 0, NULL, data, size, done, private, 1044 ZIO_TYPE_READ, priority, flags | ZIO_FLAG_PHYSICAL, vd, offset, 1045 NULL, ZIO_STAGE_OPEN, ZIO_READ_PHYS_PIPELINE); 1046 1047 zio->io_prop.zp_checksum = checksum; 1048 1049 return (zio); 1050} 1051 1052zio_t * 1053zio_write_phys(zio_t *pio, vdev_t *vd, uint64_t offset, uint64_t size, 1054 void *data, int checksum, zio_done_func_t *done, void *private, 1055 zio_priority_t priority, enum zio_flag flags, boolean_t labels) 1056{ 1057 zio_t *zio; 1058 1059 ASSERT(vd->vdev_children == 0); 1060 ASSERT(!labels || offset + size <= VDEV_LABEL_START_SIZE || 1061 offset >= vd->vdev_psize - VDEV_LABEL_END_SIZE); 1062 ASSERT3U(offset + size, <=, vd->vdev_psize); 1063 1064 zio = zio_create(pio, vd->vdev_spa, 0, NULL, data, size, done, private, 1065 ZIO_TYPE_WRITE, priority, flags | ZIO_FLAG_PHYSICAL, vd, offset, 1066 NULL, ZIO_STAGE_OPEN, ZIO_WRITE_PHYS_PIPELINE); 1067 1068 zio->io_prop.zp_checksum = checksum; 1069 1070 if (zio_checksum_table[checksum].ci_flags & ZCHECKSUM_FLAG_EMBEDDED) { 1071 /* 1072 * zec checksums are necessarily destructive -- they modify 1073 * the end of the write buffer to hold the verifier/checksum. 1074 * Therefore, we must make a local copy in case the data is 1075 * being written to multiple places in parallel. 1076 */ 1077 void *wbuf = zio_buf_alloc(size); 1078 bcopy(data, wbuf, size); 1079 zio_push_transform(zio, wbuf, size, size, NULL); 1080 } 1081 1082 return (zio); 1083} 1084 1085/* 1086 * Create a child I/O to do some work for us. 1087 */ 1088zio_t * 1089zio_vdev_child_io(zio_t *pio, blkptr_t *bp, vdev_t *vd, uint64_t offset, 1090 void *data, uint64_t size, int type, zio_priority_t priority, 1091 enum zio_flag flags, zio_done_func_t *done, void *private) 1092{ 1093 enum zio_stage pipeline = ZIO_VDEV_CHILD_PIPELINE; 1094 zio_t *zio; 1095 1096 ASSERT(vd->vdev_parent == 1097 (pio->io_vd ? pio->io_vd : pio->io_spa->spa_root_vdev)); 1098 1099 if (type == ZIO_TYPE_READ && bp != NULL) { 1100 /* 1101 * If we have the bp, then the child should perform the 1102 * checksum and the parent need not. This pushes error 1103 * detection as close to the leaves as possible and 1104 * eliminates redundant checksums in the interior nodes. 1105 */ 1106 pipeline |= ZIO_STAGE_CHECKSUM_VERIFY; 1107 pio->io_pipeline &= ~ZIO_STAGE_CHECKSUM_VERIFY; 1108 } 1109 1110 /* Not all IO types require vdev io done stage e.g. free */ 1111 if (!(pio->io_pipeline & ZIO_STAGE_VDEV_IO_DONE)) 1112 pipeline &= ~ZIO_STAGE_VDEV_IO_DONE; 1113 1114 if (vd->vdev_children == 0) 1115 offset += VDEV_LABEL_START_SIZE; 1116 1117 flags |= ZIO_VDEV_CHILD_FLAGS(pio) | ZIO_FLAG_DONT_PROPAGATE; 1118 1119 /* 1120 * If we've decided to do a repair, the write is not speculative -- 1121 * even if the original read was. 1122 */ 1123 if (flags & ZIO_FLAG_IO_REPAIR) 1124 flags &= ~ZIO_FLAG_SPECULATIVE; 1125 1126 /* 1127 * If we're creating a child I/O that is not associated with a 1128 * top-level vdev, then the child zio is not an allocating I/O. 1129 * If this is a retried I/O then we ignore it since we will 1130 * have already processed the original allocating I/O. 1131 */ 1132 if (flags & ZIO_FLAG_IO_ALLOCATING && 1133 (vd != vd->vdev_top || (flags & ZIO_FLAG_IO_RETRY))) { 1134 metaslab_class_t *mc = spa_normal_class(pio->io_spa); 1135 1136 ASSERT(mc->mc_alloc_throttle_enabled); 1137 ASSERT(type == ZIO_TYPE_WRITE); 1138 ASSERT(priority == ZIO_PRIORITY_ASYNC_WRITE); 1139 ASSERT(!(flags & ZIO_FLAG_IO_REPAIR)); 1140 ASSERT(!(pio->io_flags & ZIO_FLAG_IO_REWRITE) || 1141 pio->io_child_type == ZIO_CHILD_GANG); 1142 1143 flags &= ~ZIO_FLAG_IO_ALLOCATING; 1144 } 1145 1146 zio = zio_create(pio, pio->io_spa, pio->io_txg, bp, data, size, 1147 done, private, type, priority, flags, vd, offset, &pio->io_bookmark, 1148 ZIO_STAGE_VDEV_IO_START >> 1, pipeline); 1149 ASSERT3U(zio->io_child_type, ==, ZIO_CHILD_VDEV); 1150 1151 zio->io_physdone = pio->io_physdone; 1152 if (vd->vdev_ops->vdev_op_leaf && zio->io_logical != NULL) 1153 zio->io_logical->io_phys_children++; 1154 1155 return (zio); 1156} 1157 1158zio_t * 1159zio_vdev_delegated_io(vdev_t *vd, uint64_t offset, void *data, uint64_t size, 1160 int type, zio_priority_t priority, enum zio_flag flags, 1161 zio_done_func_t *done, void *private) 1162{ 1163 zio_t *zio; 1164 1165 ASSERT(vd->vdev_ops->vdev_op_leaf); 1166 1167 zio = zio_create(NULL, vd->vdev_spa, 0, NULL, 1168 data, size, done, private, type, priority, 1169 flags | ZIO_FLAG_CANFAIL | ZIO_FLAG_DONT_RETRY | ZIO_FLAG_DELEGATED, 1170 vd, offset, NULL, 1171 ZIO_STAGE_VDEV_IO_START >> 1, ZIO_VDEV_CHILD_PIPELINE); 1172 1173 return (zio); 1174} 1175 1176void 1177zio_flush(zio_t *zio, vdev_t *vd) 1178{ 1179 zio_nowait(zio_ioctl(zio, zio->io_spa, vd, DKIOCFLUSHWRITECACHE, 0, 0, 1180 NULL, NULL, ZIO_PRIORITY_NOW, 1181 ZIO_FLAG_CANFAIL | ZIO_FLAG_DONT_PROPAGATE | ZIO_FLAG_DONT_RETRY)); 1182} 1183 1184zio_t * 1185zio_trim(zio_t *zio, spa_t *spa, vdev_t *vd, uint64_t offset, uint64_t size) 1186{ 1187 1188 ASSERT(vd->vdev_ops->vdev_op_leaf); 1189 1190 return (zio_create(zio, spa, 0, NULL, NULL, size, NULL, NULL, 1191 ZIO_TYPE_FREE, ZIO_PRIORITY_TRIM, ZIO_FLAG_DONT_AGGREGATE | 1192 ZIO_FLAG_CANFAIL | ZIO_FLAG_DONT_PROPAGATE | ZIO_FLAG_DONT_RETRY, 1193 vd, offset, NULL, ZIO_STAGE_OPEN, ZIO_FREE_PHYS_PIPELINE)); 1194} 1195 1196void 1197zio_shrink(zio_t *zio, uint64_t size) 1198{ 1199 ASSERT(zio->io_executor == NULL); 1200 ASSERT(zio->io_orig_size == zio->io_size); 1201 ASSERT(size <= zio->io_size); 1202 1203 /* 1204 * We don't shrink for raidz because of problems with the 1205 * reconstruction when reading back less than the block size. 1206 * Note, BP_IS_RAIDZ() assumes no compression. 1207 */ 1208 ASSERT(BP_GET_COMPRESS(zio->io_bp) == ZIO_COMPRESS_OFF); 1209 if (!BP_IS_RAIDZ(zio->io_bp)) 1210 zio->io_orig_size = zio->io_size = size; 1211} 1212 1213/* 1214 * ========================================================================== 1215 * Prepare to read and write logical blocks 1216 * ========================================================================== 1217 */ 1218 1219static int 1220zio_read_bp_init(zio_t *zio) 1221{ 1222 blkptr_t *bp = zio->io_bp; 1223 1224 if (BP_GET_COMPRESS(bp) != ZIO_COMPRESS_OFF && 1225 zio->io_child_type == ZIO_CHILD_LOGICAL && 1226 !(zio->io_flags & ZIO_FLAG_RAW)) { 1227 uint64_t psize = 1228 BP_IS_EMBEDDED(bp) ? BPE_GET_PSIZE(bp) : BP_GET_PSIZE(bp); 1229 void *cbuf = zio_buf_alloc(psize); 1230 1231 zio_push_transform(zio, cbuf, psize, psize, zio_decompress); 1232 } 1233 1234 if (BP_IS_EMBEDDED(bp) && BPE_GET_ETYPE(bp) == BP_EMBEDDED_TYPE_DATA) { 1235 zio->io_pipeline = ZIO_INTERLOCK_PIPELINE; 1236 decode_embedded_bp_compressed(bp, zio->io_data); 1237 } else { 1238 ASSERT(!BP_IS_EMBEDDED(bp)); 1239 } 1240 1241 if (!DMU_OT_IS_METADATA(BP_GET_TYPE(bp)) && BP_GET_LEVEL(bp) == 0) 1242 zio->io_flags |= ZIO_FLAG_DONT_CACHE; 1243 1244 if (BP_GET_TYPE(bp) == DMU_OT_DDT_ZAP) 1245 zio->io_flags |= ZIO_FLAG_DONT_CACHE; 1246 1247 if (BP_GET_DEDUP(bp) && zio->io_child_type == ZIO_CHILD_LOGICAL) 1248 zio->io_pipeline = ZIO_DDT_READ_PIPELINE; 1249 1250 return (ZIO_PIPELINE_CONTINUE); 1251} 1252 1253static int 1254zio_write_bp_init(zio_t *zio) 1255{ 1256 if (!IO_IS_ALLOCATING(zio)) 1257 return (ZIO_PIPELINE_CONTINUE); 1258 1259 ASSERT(zio->io_child_type != ZIO_CHILD_DDT); 1260 1261 if (zio->io_bp_override) { 1262 blkptr_t *bp = zio->io_bp; 1263 zio_prop_t *zp = &zio->io_prop; 1264 1265 ASSERT(bp->blk_birth != zio->io_txg); 1266 ASSERT(BP_GET_DEDUP(zio->io_bp_override) == 0); 1267 1268 *bp = *zio->io_bp_override; 1269 zio->io_pipeline = ZIO_INTERLOCK_PIPELINE; 1270 1271 if (BP_IS_EMBEDDED(bp)) 1272 return (ZIO_PIPELINE_CONTINUE); 1273 1274 /* 1275 * If we've been overridden and nopwrite is set then 1276 * set the flag accordingly to indicate that a nopwrite 1277 * has already occurred. 1278 */ 1279 if (!BP_IS_HOLE(bp) && zp->zp_nopwrite) { 1280 ASSERT(!zp->zp_dedup); 1281 ASSERT3U(BP_GET_CHECKSUM(bp), ==, zp->zp_checksum); 1282 zio->io_flags |= ZIO_FLAG_NOPWRITE; 1283 return (ZIO_PIPELINE_CONTINUE); 1284 } 1285 1286 ASSERT(!zp->zp_nopwrite); 1287 1288 if (BP_IS_HOLE(bp) || !zp->zp_dedup) 1289 return (ZIO_PIPELINE_CONTINUE); 1290 1291 ASSERT((zio_checksum_table[zp->zp_checksum].ci_flags & 1292 ZCHECKSUM_FLAG_DEDUP) || zp->zp_dedup_verify); 1293 1294 if (BP_GET_CHECKSUM(bp) == zp->zp_checksum) { 1295 BP_SET_DEDUP(bp, 1); 1296 zio->io_pipeline |= ZIO_STAGE_DDT_WRITE; 1297 return (ZIO_PIPELINE_CONTINUE); 1298 } 1299 1300 /* 1301 * We were unable to handle this as an override bp, treat 1302 * it as a regular write I/O. 1303 */ 1304 zio->io_bp_override = NULL; 1305 *bp = zio->io_bp_orig; 1306 zio->io_pipeline = zio->io_orig_pipeline; 1307 } 1308 1309 return (ZIO_PIPELINE_CONTINUE); 1310} 1311 1312static int 1313zio_write_compress(zio_t *zio) 1314{ 1315 spa_t *spa = zio->io_spa; 1316 zio_prop_t *zp = &zio->io_prop; 1317 enum zio_compress compress = zp->zp_compress; 1318 blkptr_t *bp = zio->io_bp; 1319 uint64_t lsize = zio->io_size; 1320 uint64_t psize = lsize; 1321 int pass = 1; 1322 1323 /* 1324 * If our children haven't all reached the ready stage, 1325 * wait for them and then repeat this pipeline stage. 1326 */ 1327 if (zio_wait_for_children(zio, ZIO_CHILD_GANG, ZIO_WAIT_READY) || 1328 zio_wait_for_children(zio, ZIO_CHILD_LOGICAL, ZIO_WAIT_READY)) 1329 return (ZIO_PIPELINE_STOP); 1330 1331 if (!IO_IS_ALLOCATING(zio)) 1332 return (ZIO_PIPELINE_CONTINUE); 1333 1334 if (zio->io_children_ready != NULL) { 1335 /* 1336 * Now that all our children are ready, run the callback 1337 * associated with this zio in case it wants to modify the 1338 * data to be written. 1339 */ 1340 ASSERT3U(zp->zp_level, >, 0); 1341 zio->io_children_ready(zio); 1342 } 1343 1344 ASSERT(zio->io_child_type != ZIO_CHILD_DDT); 1345 ASSERT(zio->io_bp_override == NULL); 1346 1347 if (!BP_IS_HOLE(bp) && bp->blk_birth == zio->io_txg) { 1348 /* 1349 * We're rewriting an existing block, which means we're 1350 * working on behalf of spa_sync(). For spa_sync() to 1351 * converge, it must eventually be the case that we don't 1352 * have to allocate new blocks. But compression changes 1353 * the blocksize, which forces a reallocate, and makes 1354 * convergence take longer. Therefore, after the first 1355 * few passes, stop compressing to ensure convergence. 1356 */ 1357 pass = spa_sync_pass(spa); 1358 1359 ASSERT(zio->io_txg == spa_syncing_txg(spa)); 1360 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL); 1361 ASSERT(!BP_GET_DEDUP(bp)); 1362 1363 if (pass >= zfs_sync_pass_dont_compress) 1364 compress = ZIO_COMPRESS_OFF; 1365 1366 /* Make sure someone doesn't change their mind on overwrites */ 1367 ASSERT(BP_IS_EMBEDDED(bp) || MIN(zp->zp_copies + BP_IS_GANG(bp), 1368 spa_max_replication(spa)) == BP_GET_NDVAS(bp)); 1369 } 1370 1371 if (compress != ZIO_COMPRESS_OFF) { 1372 void *cbuf = zio_buf_alloc(lsize); 1373 psize = zio_compress_data(compress, zio->io_data, cbuf, lsize); 1374 if (psize == 0 || psize == lsize) { 1375 compress = ZIO_COMPRESS_OFF; 1376 zio_buf_free(cbuf, lsize); 1377 } else if (!zp->zp_dedup && psize <= BPE_PAYLOAD_SIZE && 1378 zp->zp_level == 0 && !DMU_OT_HAS_FILL(zp->zp_type) && 1379 spa_feature_is_enabled(spa, SPA_FEATURE_EMBEDDED_DATA)) { 1380 encode_embedded_bp_compressed(bp, 1381 cbuf, compress, lsize, psize); 1382 BPE_SET_ETYPE(bp, BP_EMBEDDED_TYPE_DATA); 1383 BP_SET_TYPE(bp, zio->io_prop.zp_type); 1384 BP_SET_LEVEL(bp, zio->io_prop.zp_level); 1385 zio_buf_free(cbuf, lsize); 1386 bp->blk_birth = zio->io_txg; 1387 zio->io_pipeline = ZIO_INTERLOCK_PIPELINE; 1388 ASSERT(spa_feature_is_active(spa, 1389 SPA_FEATURE_EMBEDDED_DATA)); 1390 return (ZIO_PIPELINE_CONTINUE); 1391 } else { 1392 /* 1393 * Round up compressed size up to the ashift 1394 * of the smallest-ashift device, and zero the tail. 1395 * This ensures that the compressed size of the BP 1396 * (and thus compressratio property) are correct, 1397 * in that we charge for the padding used to fill out 1398 * the last sector. 1399 */ 1400 ASSERT3U(spa->spa_min_ashift, >=, SPA_MINBLOCKSHIFT); 1401 size_t rounded = (size_t)P2ROUNDUP(psize, 1402 1ULL << spa->spa_min_ashift); 1403 if (rounded >= lsize) { 1404 compress = ZIO_COMPRESS_OFF; 1405 zio_buf_free(cbuf, lsize); 1406 psize = lsize; 1407 } else { 1408 bzero((char *)cbuf + psize, rounded - psize); 1409 psize = rounded; 1410 zio_push_transform(zio, cbuf, 1411 psize, lsize, NULL); 1412 } 1413 } 1414 1415 /* 1416 * We were unable to handle this as an override bp, treat 1417 * it as a regular write I/O. 1418 */ 1419 zio->io_bp_override = NULL; 1420 *bp = zio->io_bp_orig; 1421 zio->io_pipeline = zio->io_orig_pipeline; 1422 } 1423 1424 /* 1425 * The final pass of spa_sync() must be all rewrites, but the first 1426 * few passes offer a trade-off: allocating blocks defers convergence, 1427 * but newly allocated blocks are sequential, so they can be written 1428 * to disk faster. Therefore, we allow the first few passes of 1429 * spa_sync() to allocate new blocks, but force rewrites after that. 1430 * There should only be a handful of blocks after pass 1 in any case. 1431 */ 1432 if (!BP_IS_HOLE(bp) && bp->blk_birth == zio->io_txg && 1433 BP_GET_PSIZE(bp) == psize && 1434 pass >= zfs_sync_pass_rewrite) { 1435 ASSERT(psize != 0); 1436 enum zio_stage gang_stages = zio->io_pipeline & ZIO_GANG_STAGES; 1437 zio->io_pipeline = ZIO_REWRITE_PIPELINE | gang_stages; 1438 zio->io_flags |= ZIO_FLAG_IO_REWRITE; 1439 } else { 1440 BP_ZERO(bp); 1441 zio->io_pipeline = ZIO_WRITE_PIPELINE; 1442 } 1443 1444 if (psize == 0) { 1445 if (zio->io_bp_orig.blk_birth != 0 && 1446 spa_feature_is_active(spa, SPA_FEATURE_HOLE_BIRTH)) { 1447 BP_SET_LSIZE(bp, lsize); 1448 BP_SET_TYPE(bp, zp->zp_type); 1449 BP_SET_LEVEL(bp, zp->zp_level); 1450 BP_SET_BIRTH(bp, zio->io_txg, 0); 1451 } 1452 zio->io_pipeline = ZIO_INTERLOCK_PIPELINE; 1453 } else { 1454 ASSERT(zp->zp_checksum != ZIO_CHECKSUM_GANG_HEADER); 1455 BP_SET_LSIZE(bp, lsize); 1456 BP_SET_TYPE(bp, zp->zp_type); 1457 BP_SET_LEVEL(bp, zp->zp_level); 1458 BP_SET_PSIZE(bp, psize); 1459 BP_SET_COMPRESS(bp, compress); 1460 BP_SET_CHECKSUM(bp, zp->zp_checksum); 1461 BP_SET_DEDUP(bp, zp->zp_dedup); 1462 BP_SET_BYTEORDER(bp, ZFS_HOST_BYTEORDER); 1463 if (zp->zp_dedup) { 1464 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL); 1465 ASSERT(!(zio->io_flags & ZIO_FLAG_IO_REWRITE)); 1466 zio->io_pipeline = ZIO_DDT_WRITE_PIPELINE; 1467 } 1468 if (zp->zp_nopwrite) { 1469 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL); 1470 ASSERT(!(zio->io_flags & ZIO_FLAG_IO_REWRITE)); 1471 zio->io_pipeline |= ZIO_STAGE_NOP_WRITE; 1472 } 1473 } 1474 return (ZIO_PIPELINE_CONTINUE); 1475} 1476 1477static int 1478zio_free_bp_init(zio_t *zio) 1479{ 1480 blkptr_t *bp = zio->io_bp; 1481 1482 if (zio->io_child_type == ZIO_CHILD_LOGICAL) { 1483 if (BP_GET_DEDUP(bp)) 1484 zio->io_pipeline = ZIO_DDT_FREE_PIPELINE; 1485 } 1486 1487 return (ZIO_PIPELINE_CONTINUE); 1488} 1489 1490/* 1491 * ========================================================================== 1492 * Execute the I/O pipeline 1493 * ========================================================================== 1494 */ 1495 1496static void 1497zio_taskq_dispatch(zio_t *zio, zio_taskq_type_t q, boolean_t cutinline) 1498{ 1499 spa_t *spa = zio->io_spa; 1500 zio_type_t t = zio->io_type; 1501 int flags = (cutinline ? TQ_FRONT : 0); 1502 1503 ASSERT(q == ZIO_TASKQ_ISSUE || q == ZIO_TASKQ_INTERRUPT); 1504 1505 /* 1506 * If we're a config writer or a probe, the normal issue and 1507 * interrupt threads may all be blocked waiting for the config lock. 1508 * In this case, select the otherwise-unused taskq for ZIO_TYPE_NULL. 1509 */ 1510 if (zio->io_flags & (ZIO_FLAG_CONFIG_WRITER | ZIO_FLAG_PROBE)) 1511 t = ZIO_TYPE_NULL; 1512 1513 /* 1514 * A similar issue exists for the L2ARC write thread until L2ARC 2.0. 1515 */ 1516 if (t == ZIO_TYPE_WRITE && zio->io_vd && zio->io_vd->vdev_aux) 1517 t = ZIO_TYPE_NULL; 1518 1519 /* 1520 * If this is a high priority I/O, then use the high priority taskq if 1521 * available. 1522 */ 1523 if (zio->io_priority == ZIO_PRIORITY_NOW && 1524 spa->spa_zio_taskq[t][q + 1].stqs_count != 0) 1525 q++; 1526 1527 ASSERT3U(q, <, ZIO_TASKQ_TYPES); 1528 1529 /* 1530 * NB: We are assuming that the zio can only be dispatched 1531 * to a single taskq at a time. It would be a grievous error 1532 * to dispatch the zio to another taskq at the same time. 1533 */ 1534#if defined(illumos) || !defined(_KERNEL) 1535 ASSERT(zio->io_tqent.tqent_next == NULL); 1536#else 1537 ASSERT(zio->io_tqent.tqent_task.ta_pending == 0); 1538#endif 1539 spa_taskq_dispatch_ent(spa, t, q, (task_func_t *)zio_execute, zio, 1540 flags, &zio->io_tqent); 1541} 1542 1543static boolean_t 1544zio_taskq_member(zio_t *zio, zio_taskq_type_t q) 1545{ 1546 kthread_t *executor = zio->io_executor; 1547 spa_t *spa = zio->io_spa; 1548 1549 for (zio_type_t t = 0; t < ZIO_TYPES; t++) { 1550 spa_taskqs_t *tqs = &spa->spa_zio_taskq[t][q]; 1551 uint_t i; 1552 for (i = 0; i < tqs->stqs_count; i++) { 1553 if (taskq_member(tqs->stqs_taskq[i], executor)) 1554 return (B_TRUE); 1555 } 1556 } 1557 1558 return (B_FALSE); 1559} 1560 1561static int 1562zio_issue_async(zio_t *zio) 1563{ 1564 zio_taskq_dispatch(zio, ZIO_TASKQ_ISSUE, B_FALSE); 1565 1566 return (ZIO_PIPELINE_STOP); 1567} 1568 1569void 1570zio_interrupt(zio_t *zio) 1571{ 1572 zio_taskq_dispatch(zio, ZIO_TASKQ_INTERRUPT, B_FALSE); 1573} 1574 1575void 1576zio_delay_interrupt(zio_t *zio) 1577{ 1578 /* 1579 * The timeout_generic() function isn't defined in userspace, so 1580 * rather than trying to implement the function, the zio delay 1581 * functionality has been disabled for userspace builds. 1582 */ 1583 1584#ifdef _KERNEL 1585 /* 1586 * If io_target_timestamp is zero, then no delay has been registered 1587 * for this IO, thus jump to the end of this function and "skip" the 1588 * delay; issuing it directly to the zio layer. 1589 */ 1590 if (zio->io_target_timestamp != 0) { 1591 hrtime_t now = gethrtime(); 1592 1593 if (now >= zio->io_target_timestamp) { 1594 /* 1595 * This IO has already taken longer than the target 1596 * delay to complete, so we don't want to delay it 1597 * any longer; we "miss" the delay and issue it 1598 * directly to the zio layer. This is likely due to 1599 * the target latency being set to a value less than 1600 * the underlying hardware can satisfy (e.g. delay 1601 * set to 1ms, but the disks take 10ms to complete an 1602 * IO request). 1603 */ 1604 1605 DTRACE_PROBE2(zio__delay__miss, zio_t *, zio, 1606 hrtime_t, now); 1607 1608 zio_interrupt(zio); 1609 } else { 1610 hrtime_t diff = zio->io_target_timestamp - now; 1611 1612 DTRACE_PROBE3(zio__delay__hit, zio_t *, zio, 1613 hrtime_t, now, hrtime_t, diff); 1614 1615 (void) timeout_generic(CALLOUT_NORMAL, 1616 (void (*)(void *))zio_interrupt, zio, diff, 1, 0); 1617 } 1618 1619 return; 1620 } 1621#endif 1622 1623 DTRACE_PROBE1(zio__delay__skip, zio_t *, zio); 1624 zio_interrupt(zio); 1625} 1626 1627/* 1628 * Execute the I/O pipeline until one of the following occurs: 1629 * 1630 * (1) the I/O completes 1631 * (2) the pipeline stalls waiting for dependent child I/Os 1632 * (3) the I/O issues, so we're waiting for an I/O completion interrupt 1633 * (4) the I/O is delegated by vdev-level caching or aggregation 1634 * (5) the I/O is deferred due to vdev-level queueing 1635 * (6) the I/O is handed off to another thread. 1636 * 1637 * In all cases, the pipeline stops whenever there's no CPU work; it never 1638 * burns a thread in cv_wait(). 1639 * 1640 * There's no locking on io_stage because there's no legitimate way 1641 * for multiple threads to be attempting to process the same I/O. 1642 */ 1643static zio_pipe_stage_t *zio_pipeline[]; 1644 1645void 1646zio_execute(zio_t *zio) 1647{ 1648 zio->io_executor = curthread; 1649 1650 ASSERT3U(zio->io_queued_timestamp, >, 0); 1651 1652 while (zio->io_stage < ZIO_STAGE_DONE) { 1653 enum zio_stage pipeline = zio->io_pipeline; 1654 enum zio_stage stage = zio->io_stage; 1655 int rv; 1656 1657 ASSERT(!MUTEX_HELD(&zio->io_lock)); 1658 ASSERT(ISP2(stage)); 1659 ASSERT(zio->io_stall == NULL); 1660 1661 do { 1662 stage <<= 1; 1663 } while ((stage & pipeline) == 0); 1664 1665 ASSERT(stage <= ZIO_STAGE_DONE); 1666 1667 /* 1668 * If we are in interrupt context and this pipeline stage 1669 * will grab a config lock that is held across I/O, 1670 * or may wait for an I/O that needs an interrupt thread 1671 * to complete, issue async to avoid deadlock. 1672 * 1673 * For VDEV_IO_START, we cut in line so that the io will 1674 * be sent to disk promptly. 1675 */ 1676 if ((stage & ZIO_BLOCKING_STAGES) && zio->io_vd == NULL && 1677 zio_taskq_member(zio, ZIO_TASKQ_INTERRUPT)) { 1678 boolean_t cut = (stage == ZIO_STAGE_VDEV_IO_START) ? 1679 zio_requeue_io_start_cut_in_line : B_FALSE; 1680 zio_taskq_dispatch(zio, ZIO_TASKQ_ISSUE, cut); 1681 return; 1682 } 1683 1684 zio->io_stage = stage; 1685 zio->io_pipeline_trace |= zio->io_stage; 1686 rv = zio_pipeline[highbit64(stage) - 1](zio); 1687 1688 if (rv == ZIO_PIPELINE_STOP) 1689 return; 1690 1691 ASSERT(rv == ZIO_PIPELINE_CONTINUE); 1692 } 1693} 1694 1695/* 1696 * ========================================================================== 1697 * Initiate I/O, either sync or async 1698 * ========================================================================== 1699 */ 1700int 1701zio_wait(zio_t *zio) 1702{ 1703 int error; 1704 1705 ASSERT(zio->io_stage == ZIO_STAGE_OPEN); 1706 ASSERT(zio->io_executor == NULL); 1707 1708 zio->io_waiter = curthread; 1709 ASSERT0(zio->io_queued_timestamp); 1710 zio->io_queued_timestamp = gethrtime(); 1711 1712 zio_execute(zio); 1713 1714 mutex_enter(&zio->io_lock); 1715 while (zio->io_executor != NULL) 1716 cv_wait(&zio->io_cv, &zio->io_lock); 1717 mutex_exit(&zio->io_lock); 1718 1719 error = zio->io_error; 1720 zio_destroy(zio); 1721 1722 return (error); 1723} 1724 1725void 1726zio_nowait(zio_t *zio) 1727{ 1728 ASSERT(zio->io_executor == NULL); 1729 1730 if (zio->io_child_type == ZIO_CHILD_LOGICAL && 1731 zio_unique_parent(zio) == NULL) { 1732 /* 1733 * This is a logical async I/O with no parent to wait for it. 1734 * We add it to the spa_async_root_zio "Godfather" I/O which 1735 * will ensure they complete prior to unloading the pool. 1736 */ 1737 spa_t *spa = zio->io_spa; 1738 1739 zio_add_child(spa->spa_async_zio_root[CPU_SEQID], zio); 1740 } 1741 1742 ASSERT0(zio->io_queued_timestamp); 1743 zio->io_queued_timestamp = gethrtime(); 1744 zio_execute(zio); 1745} 1746 1747/* 1748 * ========================================================================== 1749 * Reexecute or suspend/resume failed I/O 1750 * ========================================================================== 1751 */ 1752 1753static void 1754zio_reexecute(zio_t *pio) 1755{ 1756 zio_t *cio, *cio_next; 1757 1758 ASSERT(pio->io_child_type == ZIO_CHILD_LOGICAL); 1759 ASSERT(pio->io_orig_stage == ZIO_STAGE_OPEN); 1760 ASSERT(pio->io_gang_leader == NULL); 1761 ASSERT(pio->io_gang_tree == NULL); 1762 1763 pio->io_flags = pio->io_orig_flags; 1764 pio->io_stage = pio->io_orig_stage; 1765 pio->io_pipeline = pio->io_orig_pipeline; 1766 pio->io_reexecute = 0; 1767 pio->io_flags |= ZIO_FLAG_REEXECUTED; 1768 pio->io_pipeline_trace = 0; 1769 pio->io_error = 0; 1770 for (int w = 0; w < ZIO_WAIT_TYPES; w++) 1771 pio->io_state[w] = 0; 1772 for (int c = 0; c < ZIO_CHILD_TYPES; c++) 1773 pio->io_child_error[c] = 0; 1774 1775 if (IO_IS_ALLOCATING(pio)) 1776 BP_ZERO(pio->io_bp); 1777 1778 /* 1779 * As we reexecute pio's children, new children could be created. 1780 * New children go to the head of pio's io_child_list, however, 1781 * so we will (correctly) not reexecute them. The key is that 1782 * the remainder of pio's io_child_list, from 'cio_next' onward, 1783 * cannot be affected by any side effects of reexecuting 'cio'. 1784 */ 1785 zio_link_t *zl = NULL; 1786 for (cio = zio_walk_children(pio, &zl); cio != NULL; cio = cio_next) { 1787 cio_next = zio_walk_children(pio, &zl); 1788 mutex_enter(&pio->io_lock); 1789 for (int w = 0; w < ZIO_WAIT_TYPES; w++) 1790 pio->io_children[cio->io_child_type][w]++; 1791 mutex_exit(&pio->io_lock); 1792 zio_reexecute(cio); 1793 } 1794 1795 /* 1796 * Now that all children have been reexecuted, execute the parent. 1797 * We don't reexecute "The Godfather" I/O here as it's the 1798 * responsibility of the caller to wait on him. 1799 */ 1800 if (!(pio->io_flags & ZIO_FLAG_GODFATHER)) { 1801 pio->io_queued_timestamp = gethrtime(); 1802 zio_execute(pio); 1803 } 1804} 1805 1806void 1807zio_suspend(spa_t *spa, zio_t *zio) 1808{ 1809 if (spa_get_failmode(spa) == ZIO_FAILURE_MODE_PANIC) 1810 fm_panic("Pool '%s' has encountered an uncorrectable I/O " 1811 "failure and the failure mode property for this pool " 1812 "is set to panic.", spa_name(spa)); 1813 1814 zfs_ereport_post(FM_EREPORT_ZFS_IO_FAILURE, spa, NULL, NULL, 0, 0); 1815 1816 mutex_enter(&spa->spa_suspend_lock); 1817 1818 if (spa->spa_suspend_zio_root == NULL) 1819 spa->spa_suspend_zio_root = zio_root(spa, NULL, NULL, 1820 ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE | 1821 ZIO_FLAG_GODFATHER); 1822 1823 spa->spa_suspended = B_TRUE; 1824 1825 if (zio != NULL) { 1826 ASSERT(!(zio->io_flags & ZIO_FLAG_GODFATHER)); 1827 ASSERT(zio != spa->spa_suspend_zio_root); 1828 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL); 1829 ASSERT(zio_unique_parent(zio) == NULL); 1830 ASSERT(zio->io_stage == ZIO_STAGE_DONE); 1831 zio_add_child(spa->spa_suspend_zio_root, zio); 1832 } 1833 1834 mutex_exit(&spa->spa_suspend_lock); 1835} 1836 1837int 1838zio_resume(spa_t *spa) 1839{ 1840 zio_t *pio; 1841 1842 /* 1843 * Reexecute all previously suspended i/o. 1844 */ 1845 mutex_enter(&spa->spa_suspend_lock); 1846 spa->spa_suspended = B_FALSE; 1847 cv_broadcast(&spa->spa_suspend_cv); 1848 pio = spa->spa_suspend_zio_root; 1849 spa->spa_suspend_zio_root = NULL; 1850 mutex_exit(&spa->spa_suspend_lock); 1851 1852 if (pio == NULL) 1853 return (0); 1854 1855 zio_reexecute(pio); 1856 return (zio_wait(pio)); 1857} 1858 1859void 1860zio_resume_wait(spa_t *spa) 1861{ 1862 mutex_enter(&spa->spa_suspend_lock); 1863 while (spa_suspended(spa)) 1864 cv_wait(&spa->spa_suspend_cv, &spa->spa_suspend_lock); 1865 mutex_exit(&spa->spa_suspend_lock); 1866} 1867 1868/* 1869 * ========================================================================== 1870 * Gang blocks. 1871 * 1872 * A gang block is a collection of small blocks that looks to the DMU 1873 * like one large block. When zio_dva_allocate() cannot find a block 1874 * of the requested size, due to either severe fragmentation or the pool 1875 * being nearly full, it calls zio_write_gang_block() to construct the 1876 * block from smaller fragments. 1877 * 1878 * A gang block consists of a gang header (zio_gbh_phys_t) and up to 1879 * three (SPA_GBH_NBLKPTRS) gang members. The gang header is just like 1880 * an indirect block: it's an array of block pointers. It consumes 1881 * only one sector and hence is allocatable regardless of fragmentation. 1882 * The gang header's bps point to its gang members, which hold the data. 1883 * 1884 * Gang blocks are self-checksumming, using the bp's <vdev, offset, txg> 1885 * as the verifier to ensure uniqueness of the SHA256 checksum. 1886 * Critically, the gang block bp's blk_cksum is the checksum of the data, 1887 * not the gang header. This ensures that data block signatures (needed for 1888 * deduplication) are independent of how the block is physically stored. 1889 * 1890 * Gang blocks can be nested: a gang member may itself be a gang block. 1891 * Thus every gang block is a tree in which root and all interior nodes are 1892 * gang headers, and the leaves are normal blocks that contain user data. 1893 * The root of the gang tree is called the gang leader. 1894 * 1895 * To perform any operation (read, rewrite, free, claim) on a gang block, 1896 * zio_gang_assemble() first assembles the gang tree (minus data leaves) 1897 * in the io_gang_tree field of the original logical i/o by recursively 1898 * reading the gang leader and all gang headers below it. This yields 1899 * an in-core tree containing the contents of every gang header and the 1900 * bps for every constituent of the gang block. 1901 * 1902 * With the gang tree now assembled, zio_gang_issue() just walks the gang tree 1903 * and invokes a callback on each bp. To free a gang block, zio_gang_issue() 1904 * calls zio_free_gang() -- a trivial wrapper around zio_free() -- for each bp. 1905 * zio_claim_gang() provides a similarly trivial wrapper for zio_claim(). 1906 * zio_read_gang() is a wrapper around zio_read() that omits reading gang 1907 * headers, since we already have those in io_gang_tree. zio_rewrite_gang() 1908 * performs a zio_rewrite() of the data or, for gang headers, a zio_rewrite() 1909 * of the gang header plus zio_checksum_compute() of the data to update the 1910 * gang header's blk_cksum as described above. 1911 * 1912 * The two-phase assemble/issue model solves the problem of partial failure -- 1913 * what if you'd freed part of a gang block but then couldn't read the 1914 * gang header for another part? Assembling the entire gang tree first 1915 * ensures that all the necessary gang header I/O has succeeded before 1916 * starting the actual work of free, claim, or write. Once the gang tree 1917 * is assembled, free and claim are in-memory operations that cannot fail. 1918 * 1919 * In the event that a gang write fails, zio_dva_unallocate() walks the 1920 * gang tree to immediately free (i.e. insert back into the space map) 1921 * everything we've allocated. This ensures that we don't get ENOSPC 1922 * errors during repeated suspend/resume cycles due to a flaky device. 1923 * 1924 * Gang rewrites only happen during sync-to-convergence. If we can't assemble 1925 * the gang tree, we won't modify the block, so we can safely defer the free 1926 * (knowing that the block is still intact). If we *can* assemble the gang 1927 * tree, then even if some of the rewrites fail, zio_dva_unallocate() will free 1928 * each constituent bp and we can allocate a new block on the next sync pass. 1929 * 1930 * In all cases, the gang tree allows complete recovery from partial failure. 1931 * ========================================================================== 1932 */ 1933 1934static zio_t * 1935zio_read_gang(zio_t *pio, blkptr_t *bp, zio_gang_node_t *gn, void *data) 1936{ 1937 if (gn != NULL) 1938 return (pio); 1939 1940 return (zio_read(pio, pio->io_spa, bp, data, BP_GET_PSIZE(bp), 1941 NULL, NULL, pio->io_priority, ZIO_GANG_CHILD_FLAGS(pio), 1942 &pio->io_bookmark)); 1943} 1944 1945zio_t * 1946zio_rewrite_gang(zio_t *pio, blkptr_t *bp, zio_gang_node_t *gn, void *data) 1947{ 1948 zio_t *zio; 1949 1950 if (gn != NULL) { 1951 zio = zio_rewrite(pio, pio->io_spa, pio->io_txg, bp, 1952 gn->gn_gbh, SPA_GANGBLOCKSIZE, NULL, NULL, pio->io_priority, 1953 ZIO_GANG_CHILD_FLAGS(pio), &pio->io_bookmark); 1954 /* 1955 * As we rewrite each gang header, the pipeline will compute 1956 * a new gang block header checksum for it; but no one will 1957 * compute a new data checksum, so we do that here. The one 1958 * exception is the gang leader: the pipeline already computed 1959 * its data checksum because that stage precedes gang assembly. 1960 * (Presently, nothing actually uses interior data checksums; 1961 * this is just good hygiene.) 1962 */ 1963 if (gn != pio->io_gang_leader->io_gang_tree) { 1964 zio_checksum_compute(zio, BP_GET_CHECKSUM(bp), 1965 data, BP_GET_PSIZE(bp)); 1966 } 1967 /* 1968 * If we are here to damage data for testing purposes, 1969 * leave the GBH alone so that we can detect the damage. 1970 */ 1971 if (pio->io_gang_leader->io_flags & ZIO_FLAG_INDUCE_DAMAGE) 1972 zio->io_pipeline &= ~ZIO_VDEV_IO_STAGES; 1973 } else { 1974 zio = zio_rewrite(pio, pio->io_spa, pio->io_txg, bp, 1975 data, BP_GET_PSIZE(bp), NULL, NULL, pio->io_priority, 1976 ZIO_GANG_CHILD_FLAGS(pio), &pio->io_bookmark); 1977 } 1978 1979 return (zio); 1980} 1981 1982/* ARGSUSED */ 1983zio_t * 1984zio_free_gang(zio_t *pio, blkptr_t *bp, zio_gang_node_t *gn, void *data) 1985{ 1986 return (zio_free_sync(pio, pio->io_spa, pio->io_txg, bp, 1987 BP_IS_GANG(bp) ? SPA_GANGBLOCKSIZE : BP_GET_PSIZE(bp), 1988 ZIO_GANG_CHILD_FLAGS(pio))); 1989} 1990 1991/* ARGSUSED */ 1992zio_t * 1993zio_claim_gang(zio_t *pio, blkptr_t *bp, zio_gang_node_t *gn, void *data) 1994{ 1995 return (zio_claim(pio, pio->io_spa, pio->io_txg, bp, 1996 NULL, NULL, ZIO_GANG_CHILD_FLAGS(pio))); 1997} 1998 1999static zio_gang_issue_func_t *zio_gang_issue_func[ZIO_TYPES] = { 2000 NULL, 2001 zio_read_gang, 2002 zio_rewrite_gang, 2003 zio_free_gang, 2004 zio_claim_gang, 2005 NULL 2006}; 2007 2008static void zio_gang_tree_assemble_done(zio_t *zio); 2009 2010static zio_gang_node_t * 2011zio_gang_node_alloc(zio_gang_node_t **gnpp) 2012{ 2013 zio_gang_node_t *gn; 2014 2015 ASSERT(*gnpp == NULL); 2016 2017 gn = kmem_zalloc(sizeof (*gn), KM_SLEEP); 2018 gn->gn_gbh = zio_buf_alloc(SPA_GANGBLOCKSIZE); 2019 *gnpp = gn; 2020 2021 return (gn); 2022} 2023 2024static void 2025zio_gang_node_free(zio_gang_node_t **gnpp) 2026{ 2027 zio_gang_node_t *gn = *gnpp; 2028 2029 for (int g = 0; g < SPA_GBH_NBLKPTRS; g++) 2030 ASSERT(gn->gn_child[g] == NULL); 2031 2032 zio_buf_free(gn->gn_gbh, SPA_GANGBLOCKSIZE); 2033 kmem_free(gn, sizeof (*gn)); 2034 *gnpp = NULL; 2035} 2036 2037static void 2038zio_gang_tree_free(zio_gang_node_t **gnpp) 2039{ 2040 zio_gang_node_t *gn = *gnpp; 2041 2042 if (gn == NULL) 2043 return; 2044 2045 for (int g = 0; g < SPA_GBH_NBLKPTRS; g++) 2046 zio_gang_tree_free(&gn->gn_child[g]); 2047 2048 zio_gang_node_free(gnpp); 2049} 2050 2051static void 2052zio_gang_tree_assemble(zio_t *gio, blkptr_t *bp, zio_gang_node_t **gnpp) 2053{ 2054 zio_gang_node_t *gn = zio_gang_node_alloc(gnpp); 2055 2056 ASSERT(gio->io_gang_leader == gio); 2057 ASSERT(BP_IS_GANG(bp)); 2058 2059 zio_nowait(zio_read(gio, gio->io_spa, bp, gn->gn_gbh, 2060 SPA_GANGBLOCKSIZE, zio_gang_tree_assemble_done, gn, 2061 gio->io_priority, ZIO_GANG_CHILD_FLAGS(gio), &gio->io_bookmark)); 2062} 2063 2064static void 2065zio_gang_tree_assemble_done(zio_t *zio) 2066{ 2067 zio_t *gio = zio->io_gang_leader; 2068 zio_gang_node_t *gn = zio->io_private; 2069 blkptr_t *bp = zio->io_bp; 2070 2071 ASSERT(gio == zio_unique_parent(zio)); 2072 ASSERT(zio->io_child_count == 0); 2073 2074 if (zio->io_error) 2075 return; 2076 2077 if (BP_SHOULD_BYTESWAP(bp)) 2078 byteswap_uint64_array(zio->io_data, zio->io_size); 2079 2080 ASSERT(zio->io_data == gn->gn_gbh); 2081 ASSERT(zio->io_size == SPA_GANGBLOCKSIZE); 2082 ASSERT(gn->gn_gbh->zg_tail.zec_magic == ZEC_MAGIC); 2083 2084 for (int g = 0; g < SPA_GBH_NBLKPTRS; g++) { 2085 blkptr_t *gbp = &gn->gn_gbh->zg_blkptr[g]; 2086 if (!BP_IS_GANG(gbp)) 2087 continue; 2088 zio_gang_tree_assemble(gio, gbp, &gn->gn_child[g]); 2089 } 2090} 2091 2092static void 2093zio_gang_tree_issue(zio_t *pio, zio_gang_node_t *gn, blkptr_t *bp, void *data) 2094{ 2095 zio_t *gio = pio->io_gang_leader; 2096 zio_t *zio; 2097 2098 ASSERT(BP_IS_GANG(bp) == !!gn); 2099 ASSERT(BP_GET_CHECKSUM(bp) == BP_GET_CHECKSUM(gio->io_bp)); 2100 ASSERT(BP_GET_LSIZE(bp) == BP_GET_PSIZE(bp) || gn == gio->io_gang_tree); 2101 2102 /* 2103 * If you're a gang header, your data is in gn->gn_gbh. 2104 * If you're a gang member, your data is in 'data' and gn == NULL. 2105 */ 2106 zio = zio_gang_issue_func[gio->io_type](pio, bp, gn, data); 2107 2108 if (gn != NULL) { 2109 ASSERT(gn->gn_gbh->zg_tail.zec_magic == ZEC_MAGIC); 2110 2111 for (int g = 0; g < SPA_GBH_NBLKPTRS; g++) { 2112 blkptr_t *gbp = &gn->gn_gbh->zg_blkptr[g]; 2113 if (BP_IS_HOLE(gbp)) 2114 continue; 2115 zio_gang_tree_issue(zio, gn->gn_child[g], gbp, data); 2116 data = (char *)data + BP_GET_PSIZE(gbp); 2117 } 2118 } 2119 2120 if (gn == gio->io_gang_tree && gio->io_data != NULL) 2121 ASSERT3P((char *)gio->io_data + gio->io_size, ==, data); 2122 2123 if (zio != pio) 2124 zio_nowait(zio); 2125} 2126 2127static int 2128zio_gang_assemble(zio_t *zio) 2129{ 2130 blkptr_t *bp = zio->io_bp; 2131 2132 ASSERT(BP_IS_GANG(bp) && zio->io_gang_leader == NULL); 2133 ASSERT(zio->io_child_type > ZIO_CHILD_GANG); 2134 2135 zio->io_gang_leader = zio; 2136 2137 zio_gang_tree_assemble(zio, bp, &zio->io_gang_tree); 2138 2139 return (ZIO_PIPELINE_CONTINUE); 2140} 2141 2142static int 2143zio_gang_issue(zio_t *zio) 2144{ 2145 blkptr_t *bp = zio->io_bp; 2146 2147 if (zio_wait_for_children(zio, ZIO_CHILD_GANG, ZIO_WAIT_DONE)) 2148 return (ZIO_PIPELINE_STOP); 2149 2150 ASSERT(BP_IS_GANG(bp) && zio->io_gang_leader == zio); 2151 ASSERT(zio->io_child_type > ZIO_CHILD_GANG); 2152 2153 if (zio->io_child_error[ZIO_CHILD_GANG] == 0) 2154 zio_gang_tree_issue(zio, zio->io_gang_tree, bp, zio->io_data); 2155 else 2156 zio_gang_tree_free(&zio->io_gang_tree); 2157 2158 zio->io_pipeline = ZIO_INTERLOCK_PIPELINE; 2159 2160 return (ZIO_PIPELINE_CONTINUE); 2161} 2162 2163static void 2164zio_write_gang_member_ready(zio_t *zio) 2165{ 2166 zio_t *pio = zio_unique_parent(zio); 2167 zio_t *gio = zio->io_gang_leader; 2168 dva_t *cdva = zio->io_bp->blk_dva; 2169 dva_t *pdva = pio->io_bp->blk_dva; 2170 uint64_t asize; 2171 2172 if (BP_IS_HOLE(zio->io_bp)) 2173 return; 2174 2175 ASSERT(BP_IS_HOLE(&zio->io_bp_orig)); 2176 2177 ASSERT(zio->io_child_type == ZIO_CHILD_GANG); 2178 ASSERT3U(zio->io_prop.zp_copies, ==, gio->io_prop.zp_copies); 2179 ASSERT3U(zio->io_prop.zp_copies, <=, BP_GET_NDVAS(zio->io_bp)); 2180 ASSERT3U(pio->io_prop.zp_copies, <=, BP_GET_NDVAS(pio->io_bp)); 2181 ASSERT3U(BP_GET_NDVAS(zio->io_bp), <=, BP_GET_NDVAS(pio->io_bp)); 2182 2183 mutex_enter(&pio->io_lock); 2184 for (int d = 0; d < BP_GET_NDVAS(zio->io_bp); d++) { 2185 ASSERT(DVA_GET_GANG(&pdva[d])); 2186 asize = DVA_GET_ASIZE(&pdva[d]); 2187 asize += DVA_GET_ASIZE(&cdva[d]); 2188 DVA_SET_ASIZE(&pdva[d], asize); 2189 } 2190 mutex_exit(&pio->io_lock); 2191} 2192 2193static int 2194zio_write_gang_block(zio_t *pio) 2195{ 2196 spa_t *spa = pio->io_spa; 2197 metaslab_class_t *mc = spa_normal_class(spa); 2198 blkptr_t *bp = pio->io_bp; 2199 zio_t *gio = pio->io_gang_leader; 2200 zio_t *zio; 2201 zio_gang_node_t *gn, **gnpp; 2202 zio_gbh_phys_t *gbh; 2203 uint64_t txg = pio->io_txg; 2204 uint64_t resid = pio->io_size; 2205 uint64_t lsize; 2206 int copies = gio->io_prop.zp_copies; 2207 int gbh_copies = MIN(copies + 1, spa_max_replication(spa)); 2208 zio_prop_t zp; 2209 int error; 2210 2211 int flags = METASLAB_HINTBP_FAVOR | METASLAB_GANG_HEADER; 2212 if (pio->io_flags & ZIO_FLAG_IO_ALLOCATING) { 2213 ASSERT(pio->io_priority == ZIO_PRIORITY_ASYNC_WRITE); 2214 ASSERT(!(pio->io_flags & ZIO_FLAG_NODATA)); 2215 2216 flags |= METASLAB_ASYNC_ALLOC; 2217 VERIFY(refcount_held(&mc->mc_alloc_slots, pio)); 2218 2219 /* 2220 * The logical zio has already placed a reservation for 2221 * 'copies' allocation slots but gang blocks may require 2222 * additional copies. These additional copies 2223 * (i.e. gbh_copies - copies) are guaranteed to succeed 2224 * since metaslab_class_throttle_reserve() always allows 2225 * additional reservations for gang blocks. 2226 */ 2227 VERIFY(metaslab_class_throttle_reserve(mc, gbh_copies - copies, 2228 pio, flags)); 2229 } 2230 2231 error = metaslab_alloc(spa, mc, SPA_GANGBLOCKSIZE, 2232 bp, gbh_copies, txg, pio == gio ? NULL : gio->io_bp, flags, pio); 2233 if (error) { 2234 if (pio->io_flags & ZIO_FLAG_IO_ALLOCATING) { 2235 ASSERT(pio->io_priority == ZIO_PRIORITY_ASYNC_WRITE); 2236 ASSERT(!(pio->io_flags & ZIO_FLAG_NODATA)); 2237 2238 /* 2239 * If we failed to allocate the gang block header then 2240 * we remove any additional allocation reservations that 2241 * we placed here. The original reservation will 2242 * be removed when the logical I/O goes to the ready 2243 * stage. 2244 */ 2245 metaslab_class_throttle_unreserve(mc, 2246 gbh_copies - copies, pio); 2247 } 2248 pio->io_error = error; 2249 return (ZIO_PIPELINE_CONTINUE); 2250 } 2251 2252 if (pio == gio) { 2253 gnpp = &gio->io_gang_tree; 2254 } else { 2255 gnpp = pio->io_private; 2256 ASSERT(pio->io_ready == zio_write_gang_member_ready); 2257 } 2258 2259 gn = zio_gang_node_alloc(gnpp); 2260 gbh = gn->gn_gbh; 2261 bzero(gbh, SPA_GANGBLOCKSIZE); 2262 2263 /* 2264 * Create the gang header. 2265 */ 2266 zio = zio_rewrite(pio, spa, txg, bp, gbh, SPA_GANGBLOCKSIZE, NULL, NULL, 2267 pio->io_priority, ZIO_GANG_CHILD_FLAGS(pio), &pio->io_bookmark); 2268 2269 /* 2270 * Create and nowait the gang children. 2271 */ 2272 for (int g = 0; resid != 0; resid -= lsize, g++) { 2273 lsize = P2ROUNDUP(resid / (SPA_GBH_NBLKPTRS - g), 2274 SPA_MINBLOCKSIZE); 2275 ASSERT(lsize >= SPA_MINBLOCKSIZE && lsize <= resid); 2276 2277 zp.zp_checksum = gio->io_prop.zp_checksum; 2278 zp.zp_compress = ZIO_COMPRESS_OFF; 2279 zp.zp_type = DMU_OT_NONE; 2280 zp.zp_level = 0; 2281 zp.zp_copies = gio->io_prop.zp_copies; 2282 zp.zp_dedup = B_FALSE; 2283 zp.zp_dedup_verify = B_FALSE; 2284 zp.zp_nopwrite = B_FALSE; 2285 2286 zio_t *cio = zio_write(zio, spa, txg, &gbh->zg_blkptr[g], 2287 (char *)pio->io_data + (pio->io_size - resid), lsize, &zp, 2288 zio_write_gang_member_ready, NULL, NULL, NULL, 2289 &gn->gn_child[g], pio->io_priority, 2290 ZIO_GANG_CHILD_FLAGS(pio), &pio->io_bookmark); 2291 2292 if (pio->io_flags & ZIO_FLAG_IO_ALLOCATING) { 2293 ASSERT(pio->io_priority == ZIO_PRIORITY_ASYNC_WRITE); 2294 ASSERT(!(pio->io_flags & ZIO_FLAG_NODATA)); 2295 2296 /* 2297 * Gang children won't throttle but we should 2298 * account for their work, so reserve an allocation 2299 * slot for them here. 2300 */ 2301 VERIFY(metaslab_class_throttle_reserve(mc, 2302 zp.zp_copies, cio, flags)); 2303 } 2304 zio_nowait(cio); 2305 } 2306 2307 /* 2308 * Set pio's pipeline to just wait for zio to finish. 2309 */ 2310 pio->io_pipeline = ZIO_INTERLOCK_PIPELINE; 2311 2312 zio_nowait(zio); 2313 2314 return (ZIO_PIPELINE_CONTINUE); 2315} 2316 2317/* 2318 * The zio_nop_write stage in the pipeline determines if allocating a 2319 * new bp is necessary. The nopwrite feature can handle writes in 2320 * either syncing or open context (i.e. zil writes) and as a result is 2321 * mutually exclusive with dedup. 2322 * 2323 * By leveraging a cryptographically secure checksum, such as SHA256, we 2324 * can compare the checksums of the new data and the old to determine if 2325 * allocating a new block is required. Note that our requirements for 2326 * cryptographic strength are fairly weak: there can't be any accidental 2327 * hash collisions, but we don't need to be secure against intentional 2328 * (malicious) collisions. To trigger a nopwrite, you have to be able 2329 * to write the file to begin with, and triggering an incorrect (hash 2330 * collision) nopwrite is no worse than simply writing to the file. 2331 * That said, there are no known attacks against the checksum algorithms 2332 * used for nopwrite, assuming that the salt and the checksums 2333 * themselves remain secret. 2334 */ 2335static int 2336zio_nop_write(zio_t *zio) 2337{ 2338 blkptr_t *bp = zio->io_bp; 2339 blkptr_t *bp_orig = &zio->io_bp_orig; 2340 zio_prop_t *zp = &zio->io_prop; 2341 2342 ASSERT(BP_GET_LEVEL(bp) == 0); 2343 ASSERT(!(zio->io_flags & ZIO_FLAG_IO_REWRITE)); 2344 ASSERT(zp->zp_nopwrite); 2345 ASSERT(!zp->zp_dedup); 2346 ASSERT(zio->io_bp_override == NULL); 2347 ASSERT(IO_IS_ALLOCATING(zio)); 2348 2349 /* 2350 * Check to see if the original bp and the new bp have matching 2351 * characteristics (i.e. same checksum, compression algorithms, etc). 2352 * If they don't then just continue with the pipeline which will 2353 * allocate a new bp. 2354 */ 2355 if (BP_IS_HOLE(bp_orig) || 2356 !(zio_checksum_table[BP_GET_CHECKSUM(bp)].ci_flags & 2357 ZCHECKSUM_FLAG_NOPWRITE) || 2358 BP_GET_CHECKSUM(bp) != BP_GET_CHECKSUM(bp_orig) || 2359 BP_GET_COMPRESS(bp) != BP_GET_COMPRESS(bp_orig) || 2360 BP_GET_DEDUP(bp) != BP_GET_DEDUP(bp_orig) || 2361 zp->zp_copies != BP_GET_NDVAS(bp_orig)) 2362 return (ZIO_PIPELINE_CONTINUE); 2363 2364 /* 2365 * If the checksums match then reset the pipeline so that we 2366 * avoid allocating a new bp and issuing any I/O. 2367 */ 2368 if (ZIO_CHECKSUM_EQUAL(bp->blk_cksum, bp_orig->blk_cksum)) { 2369 ASSERT(zio_checksum_table[zp->zp_checksum].ci_flags & 2370 ZCHECKSUM_FLAG_NOPWRITE); 2371 ASSERT3U(BP_GET_PSIZE(bp), ==, BP_GET_PSIZE(bp_orig)); 2372 ASSERT3U(BP_GET_LSIZE(bp), ==, BP_GET_LSIZE(bp_orig)); 2373 ASSERT(zp->zp_compress != ZIO_COMPRESS_OFF); 2374 ASSERT(bcmp(&bp->blk_prop, &bp_orig->blk_prop, 2375 sizeof (uint64_t)) == 0); 2376 2377 *bp = *bp_orig; 2378 zio->io_pipeline = ZIO_INTERLOCK_PIPELINE; 2379 zio->io_flags |= ZIO_FLAG_NOPWRITE; 2380 } 2381 2382 return (ZIO_PIPELINE_CONTINUE); 2383} 2384 2385/* 2386 * ========================================================================== 2387 * Dedup 2388 * ========================================================================== 2389 */ 2390static void 2391zio_ddt_child_read_done(zio_t *zio) 2392{ 2393 blkptr_t *bp = zio->io_bp; 2394 ddt_entry_t *dde = zio->io_private; 2395 ddt_phys_t *ddp; 2396 zio_t *pio = zio_unique_parent(zio); 2397 2398 mutex_enter(&pio->io_lock); 2399 ddp = ddt_phys_select(dde, bp); 2400 if (zio->io_error == 0) 2401 ddt_phys_clear(ddp); /* this ddp doesn't need repair */ 2402 if (zio->io_error == 0 && dde->dde_repair_data == NULL) 2403 dde->dde_repair_data = zio->io_data; 2404 else 2405 zio_buf_free(zio->io_data, zio->io_size); 2406 mutex_exit(&pio->io_lock); 2407} 2408 2409static int 2410zio_ddt_read_start(zio_t *zio) 2411{ 2412 blkptr_t *bp = zio->io_bp; 2413 2414 ASSERT(BP_GET_DEDUP(bp)); 2415 ASSERT(BP_GET_PSIZE(bp) == zio->io_size); 2416 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL); 2417 2418 if (zio->io_child_error[ZIO_CHILD_DDT]) { 2419 ddt_t *ddt = ddt_select(zio->io_spa, bp); 2420 ddt_entry_t *dde = ddt_repair_start(ddt, bp); 2421 ddt_phys_t *ddp = dde->dde_phys; 2422 ddt_phys_t *ddp_self = ddt_phys_select(dde, bp); 2423 blkptr_t blk; 2424 2425 ASSERT(zio->io_vsd == NULL); 2426 zio->io_vsd = dde; 2427 2428 if (ddp_self == NULL) 2429 return (ZIO_PIPELINE_CONTINUE); 2430 2431 for (int p = 0; p < DDT_PHYS_TYPES; p++, ddp++) { 2432 if (ddp->ddp_phys_birth == 0 || ddp == ddp_self) 2433 continue; 2434 ddt_bp_create(ddt->ddt_checksum, &dde->dde_key, ddp, 2435 &blk); 2436 zio_nowait(zio_read(zio, zio->io_spa, &blk, 2437 zio_buf_alloc(zio->io_size), zio->io_size, 2438 zio_ddt_child_read_done, dde, zio->io_priority, 2439 ZIO_DDT_CHILD_FLAGS(zio) | ZIO_FLAG_DONT_PROPAGATE, 2440 &zio->io_bookmark)); 2441 } 2442 return (ZIO_PIPELINE_CONTINUE); 2443 } 2444 2445 zio_nowait(zio_read(zio, zio->io_spa, bp, 2446 zio->io_data, zio->io_size, NULL, NULL, zio->io_priority, 2447 ZIO_DDT_CHILD_FLAGS(zio), &zio->io_bookmark)); 2448 2449 return (ZIO_PIPELINE_CONTINUE); 2450} 2451 2452static int 2453zio_ddt_read_done(zio_t *zio) 2454{ 2455 blkptr_t *bp = zio->io_bp; 2456 2457 if (zio_wait_for_children(zio, ZIO_CHILD_DDT, ZIO_WAIT_DONE)) 2458 return (ZIO_PIPELINE_STOP); 2459 2460 ASSERT(BP_GET_DEDUP(bp)); 2461 ASSERT(BP_GET_PSIZE(bp) == zio->io_size); 2462 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL); 2463 2464 if (zio->io_child_error[ZIO_CHILD_DDT]) { 2465 ddt_t *ddt = ddt_select(zio->io_spa, bp); 2466 ddt_entry_t *dde = zio->io_vsd; 2467 if (ddt == NULL) { 2468 ASSERT(spa_load_state(zio->io_spa) != SPA_LOAD_NONE); 2469 return (ZIO_PIPELINE_CONTINUE); 2470 } 2471 if (dde == NULL) { 2472 zio->io_stage = ZIO_STAGE_DDT_READ_START >> 1; 2473 zio_taskq_dispatch(zio, ZIO_TASKQ_ISSUE, B_FALSE); 2474 return (ZIO_PIPELINE_STOP); 2475 } 2476 if (dde->dde_repair_data != NULL) { 2477 bcopy(dde->dde_repair_data, zio->io_data, zio->io_size); 2478 zio->io_child_error[ZIO_CHILD_DDT] = 0; 2479 } 2480 ddt_repair_done(ddt, dde); 2481 zio->io_vsd = NULL; 2482 } 2483 2484 ASSERT(zio->io_vsd == NULL); 2485 2486 return (ZIO_PIPELINE_CONTINUE); 2487} 2488 2489static boolean_t 2490zio_ddt_collision(zio_t *zio, ddt_t *ddt, ddt_entry_t *dde) 2491{ 2492 spa_t *spa = zio->io_spa; 2493 2494 /* 2495 * Note: we compare the original data, not the transformed data, 2496 * because when zio->io_bp is an override bp, we will not have 2497 * pushed the I/O transforms. That's an important optimization 2498 * because otherwise we'd compress/encrypt all dmu_sync() data twice. 2499 */ 2500 for (int p = DDT_PHYS_SINGLE; p <= DDT_PHYS_TRIPLE; p++) { 2501 zio_t *lio = dde->dde_lead_zio[p]; 2502 2503 if (lio != NULL) { 2504 return (lio->io_orig_size != zio->io_orig_size || 2505 bcmp(zio->io_orig_data, lio->io_orig_data, 2506 zio->io_orig_size) != 0); 2507 } 2508 } 2509 2510 for (int p = DDT_PHYS_SINGLE; p <= DDT_PHYS_TRIPLE; p++) { 2511 ddt_phys_t *ddp = &dde->dde_phys[p]; 2512 2513 if (ddp->ddp_phys_birth != 0) { 2514 arc_buf_t *abuf = NULL; 2515 arc_flags_t aflags = ARC_FLAG_WAIT; 2516 blkptr_t blk = *zio->io_bp; 2517 int error; 2518 2519 ddt_bp_fill(ddp, &blk, ddp->ddp_phys_birth); 2520 2521 ddt_exit(ddt); 2522 2523 error = arc_read(NULL, spa, &blk, 2524 arc_getbuf_func, &abuf, ZIO_PRIORITY_SYNC_READ, 2525 ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE, 2526 &aflags, &zio->io_bookmark); 2527 2528 if (error == 0) { 2529 if (arc_buf_size(abuf) != zio->io_orig_size || 2530 bcmp(abuf->b_data, zio->io_orig_data, 2531 zio->io_orig_size) != 0) 2532 error = SET_ERROR(EEXIST); 2533 arc_buf_destroy(abuf, &abuf); 2534 } 2535 2536 ddt_enter(ddt); 2537 return (error != 0); 2538 } 2539 } 2540 2541 return (B_FALSE); 2542} 2543 2544static void 2545zio_ddt_child_write_ready(zio_t *zio) 2546{ 2547 int p = zio->io_prop.zp_copies; 2548 ddt_t *ddt = ddt_select(zio->io_spa, zio->io_bp); 2549 ddt_entry_t *dde = zio->io_private; 2550 ddt_phys_t *ddp = &dde->dde_phys[p]; 2551 zio_t *pio; 2552 2553 if (zio->io_error) 2554 return; 2555 2556 ddt_enter(ddt); 2557 2558 ASSERT(dde->dde_lead_zio[p] == zio); 2559 2560 ddt_phys_fill(ddp, zio->io_bp); 2561 2562 zio_link_t *zl = NULL; 2563 while ((pio = zio_walk_parents(zio, &zl)) != NULL) 2564 ddt_bp_fill(ddp, pio->io_bp, zio->io_txg); 2565 2566 ddt_exit(ddt); 2567} 2568 2569static void 2570zio_ddt_child_write_done(zio_t *zio) 2571{ 2572 int p = zio->io_prop.zp_copies; 2573 ddt_t *ddt = ddt_select(zio->io_spa, zio->io_bp); 2574 ddt_entry_t *dde = zio->io_private; 2575 ddt_phys_t *ddp = &dde->dde_phys[p]; 2576 2577 ddt_enter(ddt); 2578 2579 ASSERT(ddp->ddp_refcnt == 0); 2580 ASSERT(dde->dde_lead_zio[p] == zio); 2581 dde->dde_lead_zio[p] = NULL; 2582 2583 if (zio->io_error == 0) { 2584 zio_link_t *zl = NULL; 2585 while (zio_walk_parents(zio, &zl) != NULL) 2586 ddt_phys_addref(ddp); 2587 } else { 2588 ddt_phys_clear(ddp); 2589 } 2590 2591 ddt_exit(ddt); 2592} 2593 2594static void 2595zio_ddt_ditto_write_done(zio_t *zio) 2596{ 2597 int p = DDT_PHYS_DITTO; 2598 zio_prop_t *zp = &zio->io_prop; 2599 blkptr_t *bp = zio->io_bp; 2600 ddt_t *ddt = ddt_select(zio->io_spa, bp); 2601 ddt_entry_t *dde = zio->io_private; 2602 ddt_phys_t *ddp = &dde->dde_phys[p]; 2603 ddt_key_t *ddk = &dde->dde_key; 2604 2605 ddt_enter(ddt); 2606 2607 ASSERT(ddp->ddp_refcnt == 0); 2608 ASSERT(dde->dde_lead_zio[p] == zio); 2609 dde->dde_lead_zio[p] = NULL; 2610 2611 if (zio->io_error == 0) { 2612 ASSERT(ZIO_CHECKSUM_EQUAL(bp->blk_cksum, ddk->ddk_cksum)); 2613 ASSERT(zp->zp_copies < SPA_DVAS_PER_BP); 2614 ASSERT(zp->zp_copies == BP_GET_NDVAS(bp) - BP_IS_GANG(bp)); 2615 if (ddp->ddp_phys_birth != 0) 2616 ddt_phys_free(ddt, ddk, ddp, zio->io_txg); 2617 ddt_phys_fill(ddp, bp); 2618 } 2619 2620 ddt_exit(ddt); 2621} 2622 2623static int 2624zio_ddt_write(zio_t *zio) 2625{ 2626 spa_t *spa = zio->io_spa; 2627 blkptr_t *bp = zio->io_bp; 2628 uint64_t txg = zio->io_txg; 2629 zio_prop_t *zp = &zio->io_prop; 2630 int p = zp->zp_copies; 2631 int ditto_copies; 2632 zio_t *cio = NULL; 2633 zio_t *dio = NULL; 2634 ddt_t *ddt = ddt_select(spa, bp); 2635 ddt_entry_t *dde; 2636 ddt_phys_t *ddp; 2637 2638 ASSERT(BP_GET_DEDUP(bp)); 2639 ASSERT(BP_GET_CHECKSUM(bp) == zp->zp_checksum); 2640 ASSERT(BP_IS_HOLE(bp) || zio->io_bp_override); 2641 2642 ddt_enter(ddt); 2643 dde = ddt_lookup(ddt, bp, B_TRUE); 2644 ddp = &dde->dde_phys[p]; 2645 2646 if (zp->zp_dedup_verify && zio_ddt_collision(zio, ddt, dde)) { 2647 /* 2648 * If we're using a weak checksum, upgrade to a strong checksum 2649 * and try again. If we're already using a strong checksum, 2650 * we can't resolve it, so just convert to an ordinary write. 2651 * (And automatically e-mail a paper to Nature?) 2652 */ 2653 if (!(zio_checksum_table[zp->zp_checksum].ci_flags & 2654 ZCHECKSUM_FLAG_DEDUP)) { 2655 zp->zp_checksum = spa_dedup_checksum(spa); 2656 zio_pop_transforms(zio); 2657 zio->io_stage = ZIO_STAGE_OPEN; 2658 BP_ZERO(bp); 2659 } else { 2660 zp->zp_dedup = B_FALSE; 2661 } 2662 zio->io_pipeline = ZIO_WRITE_PIPELINE; 2663 ddt_exit(ddt); 2664 return (ZIO_PIPELINE_CONTINUE); 2665 } 2666 2667 ditto_copies = ddt_ditto_copies_needed(ddt, dde, ddp); 2668 ASSERT(ditto_copies < SPA_DVAS_PER_BP); 2669 2670 if (ditto_copies > ddt_ditto_copies_present(dde) && 2671 dde->dde_lead_zio[DDT_PHYS_DITTO] == NULL) { 2672 zio_prop_t czp = *zp; 2673 2674 czp.zp_copies = ditto_copies; 2675 2676 /* 2677 * If we arrived here with an override bp, we won't have run 2678 * the transform stack, so we won't have the data we need to 2679 * generate a child i/o. So, toss the override bp and restart. 2680 * This is safe, because using the override bp is just an 2681 * optimization; and it's rare, so the cost doesn't matter. 2682 */ 2683 if (zio->io_bp_override) { 2684 zio_pop_transforms(zio); 2685 zio->io_stage = ZIO_STAGE_OPEN; 2686 zio->io_pipeline = ZIO_WRITE_PIPELINE; 2687 zio->io_bp_override = NULL; 2688 BP_ZERO(bp); 2689 ddt_exit(ddt); 2690 return (ZIO_PIPELINE_CONTINUE); 2691 } 2692 2693 dio = zio_write(zio, spa, txg, bp, zio->io_orig_data, 2694 zio->io_orig_size, &czp, NULL, NULL, 2695 NULL, zio_ddt_ditto_write_done, dde, zio->io_priority, 2696 ZIO_DDT_CHILD_FLAGS(zio), &zio->io_bookmark); 2697 2698 zio_push_transform(dio, zio->io_data, zio->io_size, 0, NULL); 2699 dde->dde_lead_zio[DDT_PHYS_DITTO] = dio; 2700 } 2701 2702 if (ddp->ddp_phys_birth != 0 || dde->dde_lead_zio[p] != NULL) { 2703 if (ddp->ddp_phys_birth != 0) 2704 ddt_bp_fill(ddp, bp, txg); 2705 if (dde->dde_lead_zio[p] != NULL) 2706 zio_add_child(zio, dde->dde_lead_zio[p]); 2707 else 2708 ddt_phys_addref(ddp); 2709 } else if (zio->io_bp_override) { 2710 ASSERT(bp->blk_birth == txg); 2711 ASSERT(BP_EQUAL(bp, zio->io_bp_override)); 2712 ddt_phys_fill(ddp, bp); 2713 ddt_phys_addref(ddp); 2714 } else { 2715 cio = zio_write(zio, spa, txg, bp, zio->io_orig_data, 2716 zio->io_orig_size, zp, 2717 zio_ddt_child_write_ready, NULL, NULL, 2718 zio_ddt_child_write_done, dde, zio->io_priority, 2719 ZIO_DDT_CHILD_FLAGS(zio), &zio->io_bookmark); 2720 2721 zio_push_transform(cio, zio->io_data, zio->io_size, 0, NULL); 2722 dde->dde_lead_zio[p] = cio; 2723 } 2724 2725 ddt_exit(ddt); 2726 2727 if (cio) 2728 zio_nowait(cio); 2729 if (dio) 2730 zio_nowait(dio); 2731 2732 return (ZIO_PIPELINE_CONTINUE); 2733} 2734 2735ddt_entry_t *freedde; /* for debugging */ 2736 2737static int 2738zio_ddt_free(zio_t *zio) 2739{ 2740 spa_t *spa = zio->io_spa; 2741 blkptr_t *bp = zio->io_bp; 2742 ddt_t *ddt = ddt_select(spa, bp); 2743 ddt_entry_t *dde; 2744 ddt_phys_t *ddp; 2745 2746 ASSERT(BP_GET_DEDUP(bp)); 2747 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL); 2748 2749 ddt_enter(ddt); 2750 freedde = dde = ddt_lookup(ddt, bp, B_TRUE); 2751 ddp = ddt_phys_select(dde, bp); 2752 ddt_phys_decref(ddp); 2753 ddt_exit(ddt); 2754 2755 return (ZIO_PIPELINE_CONTINUE); 2756} 2757 2758/* 2759 * ========================================================================== 2760 * Allocate and free blocks 2761 * ========================================================================== 2762 */ 2763 2764static zio_t * 2765zio_io_to_allocate(spa_t *spa) 2766{ 2767 zio_t *zio; 2768 2769 ASSERT(MUTEX_HELD(&spa->spa_alloc_lock)); 2770 2771 zio = avl_first(&spa->spa_alloc_tree); 2772 if (zio == NULL) 2773 return (NULL); 2774 2775 ASSERT(IO_IS_ALLOCATING(zio)); 2776 2777 /* 2778 * Try to place a reservation for this zio. If we're unable to 2779 * reserve then we throttle. 2780 */ 2781 if (!metaslab_class_throttle_reserve(spa_normal_class(spa), 2782 zio->io_prop.zp_copies, zio, 0)) { 2783 return (NULL); 2784 } 2785 2786 avl_remove(&spa->spa_alloc_tree, zio); 2787 ASSERT3U(zio->io_stage, <, ZIO_STAGE_DVA_ALLOCATE); 2788 2789 return (zio); 2790} 2791 2792static int 2793zio_dva_throttle(zio_t *zio) 2794{ 2795 spa_t *spa = zio->io_spa; 2796 zio_t *nio; 2797 2798 if (zio->io_priority == ZIO_PRIORITY_SYNC_WRITE || 2799 !spa_normal_class(zio->io_spa)->mc_alloc_throttle_enabled || 2800 zio->io_child_type == ZIO_CHILD_GANG || 2801 zio->io_flags & ZIO_FLAG_NODATA) { 2802 return (ZIO_PIPELINE_CONTINUE); 2803 } 2804 2805 ASSERT(zio->io_child_type > ZIO_CHILD_GANG); 2806 2807 ASSERT3U(zio->io_queued_timestamp, >, 0); 2808 ASSERT(zio->io_stage == ZIO_STAGE_DVA_THROTTLE); 2809 2810 mutex_enter(&spa->spa_alloc_lock); 2811 2812 ASSERT(zio->io_type == ZIO_TYPE_WRITE); 2813 avl_add(&spa->spa_alloc_tree, zio); 2814 2815 nio = zio_io_to_allocate(zio->io_spa); 2816 mutex_exit(&spa->spa_alloc_lock); 2817 2818 if (nio == zio) 2819 return (ZIO_PIPELINE_CONTINUE); 2820 2821 if (nio != NULL) { 2822 ASSERT3U(nio->io_queued_timestamp, <=, 2823 zio->io_queued_timestamp); 2824 ASSERT(nio->io_stage == ZIO_STAGE_DVA_THROTTLE); 2825 /* 2826 * We are passing control to a new zio so make sure that 2827 * it is processed by a different thread. We do this to 2828 * avoid stack overflows that can occur when parents are 2829 * throttled and children are making progress. We allow 2830 * it to go to the head of the taskq since it's already 2831 * been waiting. 2832 */ 2833 zio_taskq_dispatch(nio, ZIO_TASKQ_ISSUE, B_TRUE); 2834 } 2835 return (ZIO_PIPELINE_STOP); 2836} 2837 2838void 2839zio_allocate_dispatch(spa_t *spa) 2840{ 2841 zio_t *zio; 2842 2843 mutex_enter(&spa->spa_alloc_lock); 2844 zio = zio_io_to_allocate(spa); 2845 mutex_exit(&spa->spa_alloc_lock); 2846 if (zio == NULL) 2847 return; 2848 2849 ASSERT3U(zio->io_stage, ==, ZIO_STAGE_DVA_THROTTLE); 2850 ASSERT0(zio->io_error); 2851 zio_taskq_dispatch(zio, ZIO_TASKQ_ISSUE, B_TRUE); 2852} 2853 2854static int 2855zio_dva_allocate(zio_t *zio) 2856{ 2857 spa_t *spa = zio->io_spa; 2858 metaslab_class_t *mc = spa_normal_class(spa); 2859 blkptr_t *bp = zio->io_bp; 2860 int error; 2861 int flags = 0; 2862 2863 if (zio->io_gang_leader == NULL) { 2864 ASSERT(zio->io_child_type > ZIO_CHILD_GANG); 2865 zio->io_gang_leader = zio; 2866 } 2867 2868 ASSERT(BP_IS_HOLE(bp)); 2869 ASSERT0(BP_GET_NDVAS(bp)); 2870 ASSERT3U(zio->io_prop.zp_copies, >, 0); 2871 ASSERT3U(zio->io_prop.zp_copies, <=, spa_max_replication(spa)); 2872 ASSERT3U(zio->io_size, ==, BP_GET_PSIZE(bp)); 2873 2874 if (zio->io_flags & ZIO_FLAG_NODATA) { 2875 flags |= METASLAB_DONT_THROTTLE; 2876 } 2877 if (zio->io_flags & ZIO_FLAG_GANG_CHILD) { 2878 flags |= METASLAB_GANG_CHILD; 2879 } 2880 if (zio->io_priority == ZIO_PRIORITY_ASYNC_WRITE) { 2881 flags |= METASLAB_ASYNC_ALLOC; 2882 } 2883 2884 error = metaslab_alloc(spa, mc, zio->io_size, bp, 2885 zio->io_prop.zp_copies, zio->io_txg, NULL, flags, zio); 2886 2887 if (error != 0) { 2888 spa_dbgmsg(spa, "%s: metaslab allocation failure: zio %p, " 2889 "size %llu, error %d", spa_name(spa), zio, zio->io_size, 2890 error); 2891 if (error == ENOSPC && zio->io_size > SPA_MINBLOCKSIZE) 2892 return (zio_write_gang_block(zio)); 2893 zio->io_error = error; 2894 } 2895 2896 return (ZIO_PIPELINE_CONTINUE); 2897} 2898 2899static int 2900zio_dva_free(zio_t *zio) 2901{ 2902 metaslab_free(zio->io_spa, zio->io_bp, zio->io_txg, B_FALSE); 2903 2904 return (ZIO_PIPELINE_CONTINUE); 2905} 2906 2907static int 2908zio_dva_claim(zio_t *zio) 2909{ 2910 int error; 2911 2912 error = metaslab_claim(zio->io_spa, zio->io_bp, zio->io_txg); 2913 if (error) 2914 zio->io_error = error; 2915 2916 return (ZIO_PIPELINE_CONTINUE); 2917} 2918 2919/* 2920 * Undo an allocation. This is used by zio_done() when an I/O fails 2921 * and we want to give back the block we just allocated. 2922 * This handles both normal blocks and gang blocks. 2923 */ 2924static void 2925zio_dva_unallocate(zio_t *zio, zio_gang_node_t *gn, blkptr_t *bp) 2926{ 2927 ASSERT(bp->blk_birth == zio->io_txg || BP_IS_HOLE(bp)); 2928 ASSERT(zio->io_bp_override == NULL); 2929 2930 if (!BP_IS_HOLE(bp)) 2931 metaslab_free(zio->io_spa, bp, bp->blk_birth, B_TRUE); 2932 2933 if (gn != NULL) { 2934 for (int g = 0; g < SPA_GBH_NBLKPTRS; g++) { 2935 zio_dva_unallocate(zio, gn->gn_child[g], 2936 &gn->gn_gbh->zg_blkptr[g]); 2937 } 2938 } 2939} 2940 2941/* 2942 * Try to allocate an intent log block. Return 0 on success, errno on failure. 2943 */ 2944int 2945zio_alloc_zil(spa_t *spa, uint64_t txg, blkptr_t *new_bp, blkptr_t *old_bp, 2946 uint64_t size, boolean_t *slog) 2947{ 2948 int error = 1; 2949 2950 ASSERT(txg > spa_syncing_txg(spa)); 2951 2952 error = metaslab_alloc(spa, spa_log_class(spa), size, 2953 new_bp, 1, txg, old_bp, METASLAB_HINTBP_AVOID, NULL); 2954 if (error == 0) { 2955 *slog = TRUE; 2956 } else { 2957 error = metaslab_alloc(spa, spa_normal_class(spa), size, 2958 new_bp, 1, txg, old_bp, METASLAB_HINTBP_AVOID, NULL); 2959 if (error == 0) 2960 *slog = FALSE; 2961 } 2962 2963 if (error == 0) { 2964 BP_SET_LSIZE(new_bp, size); 2965 BP_SET_PSIZE(new_bp, size); 2966 BP_SET_COMPRESS(new_bp, ZIO_COMPRESS_OFF); 2967 BP_SET_CHECKSUM(new_bp, 2968 spa_version(spa) >= SPA_VERSION_SLIM_ZIL 2969 ? ZIO_CHECKSUM_ZILOG2 : ZIO_CHECKSUM_ZILOG); 2970 BP_SET_TYPE(new_bp, DMU_OT_INTENT_LOG); 2971 BP_SET_LEVEL(new_bp, 0); 2972 BP_SET_DEDUP(new_bp, 0); 2973 BP_SET_BYTEORDER(new_bp, ZFS_HOST_BYTEORDER); 2974 } 2975 2976 return (error); 2977} 2978 2979/* 2980 * Free an intent log block. 2981 */ 2982void 2983zio_free_zil(spa_t *spa, uint64_t txg, blkptr_t *bp) 2984{ 2985 ASSERT(BP_GET_TYPE(bp) == DMU_OT_INTENT_LOG); 2986 ASSERT(!BP_IS_GANG(bp)); 2987 2988 zio_free(spa, txg, bp); 2989} 2990 2991/* 2992 * ========================================================================== 2993 * Read, write and delete to physical devices 2994 * ========================================================================== 2995 */ 2996 2997 2998/* 2999 * Issue an I/O to the underlying vdev. Typically the issue pipeline 3000 * stops after this stage and will resume upon I/O completion. 3001 * However, there are instances where the vdev layer may need to 3002 * continue the pipeline when an I/O was not issued. Since the I/O 3003 * that was sent to the vdev layer might be different than the one 3004 * currently active in the pipeline (see vdev_queue_io()), we explicitly 3005 * force the underlying vdev layers to call either zio_execute() or 3006 * zio_interrupt() to ensure that the pipeline continues with the correct I/O. 3007 */ 3008static int 3009zio_vdev_io_start(zio_t *zio) 3010{ 3011 vdev_t *vd = zio->io_vd; 3012 uint64_t align; 3013 spa_t *spa = zio->io_spa; 3014 int ret; 3015 3016 ASSERT(zio->io_error == 0); 3017 ASSERT(zio->io_child_error[ZIO_CHILD_VDEV] == 0); 3018 3019 if (vd == NULL) { 3020 if (!(zio->io_flags & ZIO_FLAG_CONFIG_WRITER)) 3021 spa_config_enter(spa, SCL_ZIO, zio, RW_READER); 3022 3023 /* 3024 * The mirror_ops handle multiple DVAs in a single BP. 3025 */ 3026 vdev_mirror_ops.vdev_op_io_start(zio); 3027 return (ZIO_PIPELINE_STOP); 3028 } 3029 3030 if (vd->vdev_ops->vdev_op_leaf && zio->io_type == ZIO_TYPE_FREE && 3031 zio->io_priority == ZIO_PRIORITY_NOW) { 3032 trim_map_free(vd, zio->io_offset, zio->io_size, zio->io_txg); 3033 return (ZIO_PIPELINE_CONTINUE); 3034 } 3035 3036 ASSERT3P(zio->io_logical, !=, zio); 3037 3038 /* 3039 * We keep track of time-sensitive I/Os so that the scan thread 3040 * can quickly react to certain workloads. In particular, we care 3041 * about non-scrubbing, top-level reads and writes with the following 3042 * characteristics: 3043 * - synchronous writes of user data to non-slog devices 3044 * - any reads of user data 3045 * When these conditions are met, adjust the timestamp of spa_last_io 3046 * which allows the scan thread to adjust its workload accordingly. 3047 */ 3048 if (!(zio->io_flags & ZIO_FLAG_SCAN_THREAD) && zio->io_bp != NULL && 3049 vd == vd->vdev_top && !vd->vdev_islog && 3050 zio->io_bookmark.zb_objset != DMU_META_OBJSET && 3051 zio->io_txg != spa_syncing_txg(spa)) { 3052 uint64_t old = spa->spa_last_io; 3053 uint64_t new = ddi_get_lbolt64(); 3054 if (old != new) 3055 (void) atomic_cas_64(&spa->spa_last_io, old, new); 3056 } 3057 3058 align = 1ULL << vd->vdev_top->vdev_ashift; 3059 3060 if (!(zio->io_flags & ZIO_FLAG_PHYSICAL) && 3061 P2PHASE(zio->io_size, align) != 0) { 3062 /* Transform logical writes to be a full physical block size. */ 3063 uint64_t asize = P2ROUNDUP(zio->io_size, align); 3064 char *abuf = NULL; 3065 if (zio->io_type == ZIO_TYPE_READ || 3066 zio->io_type == ZIO_TYPE_WRITE) 3067 abuf = zio_buf_alloc(asize); 3068 ASSERT(vd == vd->vdev_top); 3069 if (zio->io_type == ZIO_TYPE_WRITE) { 3070 bcopy(zio->io_data, abuf, zio->io_size); 3071 bzero(abuf + zio->io_size, asize - zio->io_size); 3072 } 3073 zio_push_transform(zio, abuf, asize, abuf ? asize : 0, 3074 zio_subblock); 3075 } 3076 3077 /* 3078 * If this is not a physical io, make sure that it is properly aligned 3079 * before proceeding. 3080 */ 3081 if (!(zio->io_flags & ZIO_FLAG_PHYSICAL)) { 3082 ASSERT0(P2PHASE(zio->io_offset, align)); 3083 ASSERT0(P2PHASE(zio->io_size, align)); 3084 } else { 3085 /* 3086 * For the physical io we allow alignment 3087 * to a logical block size. 3088 */ 3089 uint64_t log_align = 3090 1ULL << vd->vdev_top->vdev_logical_ashift; 3091 ASSERT0(P2PHASE(zio->io_offset, log_align)); 3092 ASSERT0(P2PHASE(zio->io_size, log_align)); 3093 } 3094 3095 VERIFY(zio->io_type == ZIO_TYPE_READ || spa_writeable(spa)); 3096 3097 /* 3098 * If this is a repair I/O, and there's no self-healing involved -- 3099 * that is, we're just resilvering what we expect to resilver -- 3100 * then don't do the I/O unless zio's txg is actually in vd's DTL. 3101 * This prevents spurious resilvering with nested replication. 3102 * For example, given a mirror of mirrors, (A+B)+(C+D), if only 3103 * A is out of date, we'll read from C+D, then use the data to 3104 * resilver A+B -- but we don't actually want to resilver B, just A. 3105 * The top-level mirror has no way to know this, so instead we just 3106 * discard unnecessary repairs as we work our way down the vdev tree. 3107 * The same logic applies to any form of nested replication: 3108 * ditto + mirror, RAID-Z + replacing, etc. This covers them all. 3109 */ 3110 if ((zio->io_flags & ZIO_FLAG_IO_REPAIR) && 3111 !(zio->io_flags & ZIO_FLAG_SELF_HEAL) && 3112 zio->io_txg != 0 && /* not a delegated i/o */ 3113 !vdev_dtl_contains(vd, DTL_PARTIAL, zio->io_txg, 1)) { 3114 ASSERT(zio->io_type == ZIO_TYPE_WRITE); 3115 zio_vdev_io_bypass(zio); 3116 return (ZIO_PIPELINE_CONTINUE); 3117 } 3118 3119 if (vd->vdev_ops->vdev_op_leaf) { 3120 switch (zio->io_type) { 3121 case ZIO_TYPE_READ: 3122 if (vdev_cache_read(zio)) 3123 return (ZIO_PIPELINE_CONTINUE); 3124 /* FALLTHROUGH */ 3125 case ZIO_TYPE_WRITE: 3126 case ZIO_TYPE_FREE: 3127 if ((zio = vdev_queue_io(zio)) == NULL) 3128 return (ZIO_PIPELINE_STOP); 3129 3130 if (!vdev_accessible(vd, zio)) { 3131 zio->io_error = SET_ERROR(ENXIO); 3132 zio_interrupt(zio); 3133 return (ZIO_PIPELINE_STOP); 3134 } 3135 break; 3136 } 3137 /* 3138 * Note that we ignore repair writes for TRIM because they can 3139 * conflict with normal writes. This isn't an issue because, by 3140 * definition, we only repair blocks that aren't freed. 3141 */ 3142 if (zio->io_type == ZIO_TYPE_WRITE && 3143 !(zio->io_flags & ZIO_FLAG_IO_REPAIR) && 3144 !trim_map_write_start(zio)) 3145 return (ZIO_PIPELINE_STOP); 3146 } 3147 3148 vd->vdev_ops->vdev_op_io_start(zio); 3149 return (ZIO_PIPELINE_STOP); 3150} 3151 3152static int 3153zio_vdev_io_done(zio_t *zio) 3154{ 3155 vdev_t *vd = zio->io_vd; 3156 vdev_ops_t *ops = vd ? vd->vdev_ops : &vdev_mirror_ops; 3157 boolean_t unexpected_error = B_FALSE; 3158 3159 if (zio_wait_for_children(zio, ZIO_CHILD_VDEV, ZIO_WAIT_DONE)) 3160 return (ZIO_PIPELINE_STOP); 3161 3162 ASSERT(zio->io_type == ZIO_TYPE_READ || 3163 zio->io_type == ZIO_TYPE_WRITE || zio->io_type == ZIO_TYPE_FREE); 3164 3165 if (vd != NULL && vd->vdev_ops->vdev_op_leaf && 3166 (zio->io_type == ZIO_TYPE_READ || zio->io_type == ZIO_TYPE_WRITE || 3167 zio->io_type == ZIO_TYPE_FREE)) { 3168 3169 if (zio->io_type == ZIO_TYPE_WRITE && 3170 !(zio->io_flags & ZIO_FLAG_IO_REPAIR)) 3171 trim_map_write_done(zio); 3172 3173 vdev_queue_io_done(zio); 3174 3175 if (zio->io_type == ZIO_TYPE_WRITE) 3176 vdev_cache_write(zio); 3177 3178 if (zio_injection_enabled && zio->io_error == 0) 3179 zio->io_error = zio_handle_device_injection(vd, 3180 zio, EIO); 3181 3182 if (zio_injection_enabled && zio->io_error == 0) 3183 zio->io_error = zio_handle_label_injection(zio, EIO); 3184 3185 if (zio->io_error) { 3186 if (zio->io_error == ENOTSUP && 3187 zio->io_type == ZIO_TYPE_FREE) { 3188 /* Not all devices support TRIM. */ 3189 } else if (!vdev_accessible(vd, zio)) { 3190 zio->io_error = SET_ERROR(ENXIO); 3191 } else { 3192 unexpected_error = B_TRUE; 3193 } 3194 } 3195 } 3196 3197 ops->vdev_op_io_done(zio); 3198 3199 if (unexpected_error) 3200 VERIFY(vdev_probe(vd, zio) == NULL); 3201 3202 return (ZIO_PIPELINE_CONTINUE); 3203} 3204 3205/* 3206 * For non-raidz ZIOs, we can just copy aside the bad data read from the 3207 * disk, and use that to finish the checksum ereport later. 3208 */ 3209static void 3210zio_vsd_default_cksum_finish(zio_cksum_report_t *zcr, 3211 const void *good_buf) 3212{ 3213 /* no processing needed */ 3214 zfs_ereport_finish_checksum(zcr, good_buf, zcr->zcr_cbdata, B_FALSE); 3215} 3216 3217/*ARGSUSED*/ 3218void 3219zio_vsd_default_cksum_report(zio_t *zio, zio_cksum_report_t *zcr, void *ignored) 3220{ 3221 void *buf = zio_buf_alloc(zio->io_size); 3222 3223 bcopy(zio->io_data, buf, zio->io_size); 3224 3225 zcr->zcr_cbinfo = zio->io_size; 3226 zcr->zcr_cbdata = buf; 3227 zcr->zcr_finish = zio_vsd_default_cksum_finish; 3228 zcr->zcr_free = zio_buf_free; 3229} 3230 3231static int 3232zio_vdev_io_assess(zio_t *zio) 3233{ 3234 vdev_t *vd = zio->io_vd; 3235 3236 if (zio_wait_for_children(zio, ZIO_CHILD_VDEV, ZIO_WAIT_DONE)) 3237 return (ZIO_PIPELINE_STOP); 3238 3239 if (vd == NULL && !(zio->io_flags & ZIO_FLAG_CONFIG_WRITER)) 3240 spa_config_exit(zio->io_spa, SCL_ZIO, zio); 3241 3242 if (zio->io_vsd != NULL) { 3243 zio->io_vsd_ops->vsd_free(zio); 3244 zio->io_vsd = NULL; 3245 } 3246 3247 if (zio_injection_enabled && zio->io_error == 0) 3248 zio->io_error = zio_handle_fault_injection(zio, EIO); 3249 3250 if (zio->io_type == ZIO_TYPE_FREE && 3251 zio->io_priority != ZIO_PRIORITY_NOW) { 3252 switch (zio->io_error) { 3253 case 0: 3254 ZIO_TRIM_STAT_INCR(bytes, zio->io_size); 3255 ZIO_TRIM_STAT_BUMP(success); 3256 break; 3257 case EOPNOTSUPP: 3258 ZIO_TRIM_STAT_BUMP(unsupported); 3259 break; 3260 default: 3261 ZIO_TRIM_STAT_BUMP(failed); 3262 break; 3263 } 3264 } 3265 3266 /* 3267 * If the I/O failed, determine whether we should attempt to retry it. 3268 * 3269 * On retry, we cut in line in the issue queue, since we don't want 3270 * compression/checksumming/etc. work to prevent our (cheap) IO reissue. 3271 */ 3272 if (zio->io_error && vd == NULL && 3273 !(zio->io_flags & (ZIO_FLAG_DONT_RETRY | ZIO_FLAG_IO_RETRY))) { 3274 ASSERT(!(zio->io_flags & ZIO_FLAG_DONT_QUEUE)); /* not a leaf */ 3275 ASSERT(!(zio->io_flags & ZIO_FLAG_IO_BYPASS)); /* not a leaf */ 3276 zio->io_error = 0; 3277 zio->io_flags |= ZIO_FLAG_IO_RETRY | 3278 ZIO_FLAG_DONT_CACHE | ZIO_FLAG_DONT_AGGREGATE; 3279 zio->io_stage = ZIO_STAGE_VDEV_IO_START >> 1; 3280 zio_taskq_dispatch(zio, ZIO_TASKQ_ISSUE, 3281 zio_requeue_io_start_cut_in_line); 3282 return (ZIO_PIPELINE_STOP); 3283 } 3284 3285 /* 3286 * If we got an error on a leaf device, convert it to ENXIO 3287 * if the device is not accessible at all. 3288 */ 3289 if (zio->io_error && vd != NULL && vd->vdev_ops->vdev_op_leaf && 3290 !vdev_accessible(vd, zio)) 3291 zio->io_error = SET_ERROR(ENXIO); 3292 3293 /* 3294 * If we can't write to an interior vdev (mirror or RAID-Z), 3295 * set vdev_cant_write so that we stop trying to allocate from it. 3296 */ 3297 if (zio->io_error == ENXIO && zio->io_type == ZIO_TYPE_WRITE && 3298 vd != NULL && !vd->vdev_ops->vdev_op_leaf) { 3299 vd->vdev_cant_write = B_TRUE; 3300 } 3301 3302 if (zio->io_error) 3303 zio->io_pipeline = ZIO_INTERLOCK_PIPELINE; 3304 3305 if (vd != NULL && vd->vdev_ops->vdev_op_leaf && 3306 zio->io_physdone != NULL) { 3307 ASSERT(!(zio->io_flags & ZIO_FLAG_DELEGATED)); 3308 ASSERT(zio->io_child_type == ZIO_CHILD_VDEV); 3309 zio->io_physdone(zio->io_logical); 3310 } 3311 3312 return (ZIO_PIPELINE_CONTINUE); 3313} 3314 3315void 3316zio_vdev_io_reissue(zio_t *zio) 3317{ 3318 ASSERT(zio->io_stage == ZIO_STAGE_VDEV_IO_START); 3319 ASSERT(zio->io_error == 0); 3320 3321 zio->io_stage >>= 1; 3322} 3323 3324void 3325zio_vdev_io_redone(zio_t *zio) 3326{ 3327 ASSERT(zio->io_stage == ZIO_STAGE_VDEV_IO_DONE); 3328 3329 zio->io_stage >>= 1; 3330} 3331 3332void 3333zio_vdev_io_bypass(zio_t *zio) 3334{ 3335 ASSERT(zio->io_stage == ZIO_STAGE_VDEV_IO_START); 3336 ASSERT(zio->io_error == 0); 3337 3338 zio->io_flags |= ZIO_FLAG_IO_BYPASS; 3339 zio->io_stage = ZIO_STAGE_VDEV_IO_ASSESS >> 1; 3340} 3341 3342/* 3343 * ========================================================================== 3344 * Generate and verify checksums 3345 * ========================================================================== 3346 */ 3347static int 3348zio_checksum_generate(zio_t *zio) 3349{ 3350 blkptr_t *bp = zio->io_bp; 3351 enum zio_checksum checksum; 3352 3353 if (bp == NULL) { 3354 /* 3355 * This is zio_write_phys(). 3356 * We're either generating a label checksum, or none at all. 3357 */ 3358 checksum = zio->io_prop.zp_checksum; 3359 3360 if (checksum == ZIO_CHECKSUM_OFF) 3361 return (ZIO_PIPELINE_CONTINUE); 3362 3363 ASSERT(checksum == ZIO_CHECKSUM_LABEL); 3364 } else { 3365 if (BP_IS_GANG(bp) && zio->io_child_type == ZIO_CHILD_GANG) { 3366 ASSERT(!IO_IS_ALLOCATING(zio)); 3367 checksum = ZIO_CHECKSUM_GANG_HEADER; 3368 } else { 3369 checksum = BP_GET_CHECKSUM(bp); 3370 } 3371 } 3372 3373 zio_checksum_compute(zio, checksum, zio->io_data, zio->io_size); 3374 3375 return (ZIO_PIPELINE_CONTINUE); 3376} 3377 3378static int 3379zio_checksum_verify(zio_t *zio) 3380{ 3381 zio_bad_cksum_t info; 3382 blkptr_t *bp = zio->io_bp; 3383 int error; 3384 3385 ASSERT(zio->io_vd != NULL); 3386 3387 if (bp == NULL) { 3388 /* 3389 * This is zio_read_phys(). 3390 * We're either verifying a label checksum, or nothing at all. 3391 */ 3392 if (zio->io_prop.zp_checksum == ZIO_CHECKSUM_OFF) 3393 return (ZIO_PIPELINE_CONTINUE); 3394 3395 ASSERT(zio->io_prop.zp_checksum == ZIO_CHECKSUM_LABEL); 3396 } 3397 3398 if ((error = zio_checksum_error(zio, &info)) != 0) { 3399 zio->io_error = error; 3400 if (error == ECKSUM && 3401 !(zio->io_flags & ZIO_FLAG_SPECULATIVE)) { 3402 zfs_ereport_start_checksum(zio->io_spa, 3403 zio->io_vd, zio, zio->io_offset, 3404 zio->io_size, NULL, &info); 3405 } 3406 } 3407 3408 return (ZIO_PIPELINE_CONTINUE); 3409} 3410 3411/* 3412 * Called by RAID-Z to ensure we don't compute the checksum twice. 3413 */ 3414void 3415zio_checksum_verified(zio_t *zio) 3416{ 3417 zio->io_pipeline &= ~ZIO_STAGE_CHECKSUM_VERIFY; 3418} 3419 3420/* 3421 * ========================================================================== 3422 * Error rank. Error are ranked in the order 0, ENXIO, ECKSUM, EIO, other. 3423 * An error of 0 indicates success. ENXIO indicates whole-device failure, 3424 * which may be transient (e.g. unplugged) or permament. ECKSUM and EIO 3425 * indicate errors that are specific to one I/O, and most likely permanent. 3426 * Any other error is presumed to be worse because we weren't expecting it. 3427 * ========================================================================== 3428 */ 3429int 3430zio_worst_error(int e1, int e2) 3431{ 3432 static int zio_error_rank[] = { 0, ENXIO, ECKSUM, EIO }; 3433 int r1, r2; 3434 3435 for (r1 = 0; r1 < sizeof (zio_error_rank) / sizeof (int); r1++) 3436 if (e1 == zio_error_rank[r1]) 3437 break; 3438 3439 for (r2 = 0; r2 < sizeof (zio_error_rank) / sizeof (int); r2++) 3440 if (e2 == zio_error_rank[r2]) 3441 break; 3442 3443 return (r1 > r2 ? e1 : e2); 3444} 3445 3446/* 3447 * ========================================================================== 3448 * I/O completion 3449 * ========================================================================== 3450 */ 3451static int 3452zio_ready(zio_t *zio) 3453{ 3454 blkptr_t *bp = zio->io_bp; 3455 zio_t *pio, *pio_next; 3456 zio_link_t *zl = NULL; 3457 3458 if (zio_wait_for_children(zio, ZIO_CHILD_GANG, ZIO_WAIT_READY) || 3459 zio_wait_for_children(zio, ZIO_CHILD_DDT, ZIO_WAIT_READY)) 3460 return (ZIO_PIPELINE_STOP); 3461 3462 if (zio->io_ready) { 3463 ASSERT(IO_IS_ALLOCATING(zio)); 3464 ASSERT(bp->blk_birth == zio->io_txg || BP_IS_HOLE(bp) || 3465 (zio->io_flags & ZIO_FLAG_NOPWRITE)); 3466 ASSERT(zio->io_children[ZIO_CHILD_GANG][ZIO_WAIT_READY] == 0); 3467 3468 zio->io_ready(zio); 3469 } 3470 3471 if (bp != NULL && bp != &zio->io_bp_copy) 3472 zio->io_bp_copy = *bp; 3473 3474 if (zio->io_error != 0) { 3475 zio->io_pipeline = ZIO_INTERLOCK_PIPELINE; 3476 3477 if (zio->io_flags & ZIO_FLAG_IO_ALLOCATING) { 3478 ASSERT(IO_IS_ALLOCATING(zio)); 3479 ASSERT(zio->io_priority == ZIO_PRIORITY_ASYNC_WRITE); 3480 /* 3481 * We were unable to allocate anything, unreserve and 3482 * issue the next I/O to allocate. 3483 */ 3484 metaslab_class_throttle_unreserve( 3485 spa_normal_class(zio->io_spa), 3486 zio->io_prop.zp_copies, zio); 3487 zio_allocate_dispatch(zio->io_spa); 3488 } 3489 } 3490 3491 mutex_enter(&zio->io_lock); 3492 zio->io_state[ZIO_WAIT_READY] = 1; 3493 pio = zio_walk_parents(zio, &zl); 3494 mutex_exit(&zio->io_lock); 3495 3496 /* 3497 * As we notify zio's parents, new parents could be added. 3498 * New parents go to the head of zio's io_parent_list, however, 3499 * so we will (correctly) not notify them. The remainder of zio's 3500 * io_parent_list, from 'pio_next' onward, cannot change because 3501 * all parents must wait for us to be done before they can be done. 3502 */ 3503 for (; pio != NULL; pio = pio_next) { 3504 pio_next = zio_walk_parents(zio, &zl); 3505 zio_notify_parent(pio, zio, ZIO_WAIT_READY); 3506 } 3507 3508 if (zio->io_flags & ZIO_FLAG_NODATA) { 3509 if (BP_IS_GANG(bp)) { 3510 zio->io_flags &= ~ZIO_FLAG_NODATA; 3511 } else { 3512 ASSERT((uintptr_t)zio->io_data < SPA_MAXBLOCKSIZE); 3513 zio->io_pipeline &= ~ZIO_VDEV_IO_STAGES; 3514 } 3515 } 3516 3517 if (zio_injection_enabled && 3518 zio->io_spa->spa_syncing_txg == zio->io_txg) 3519 zio_handle_ignored_writes(zio); 3520 3521 return (ZIO_PIPELINE_CONTINUE); 3522} 3523 3524/* 3525 * Update the allocation throttle accounting. 3526 */ 3527static void 3528zio_dva_throttle_done(zio_t *zio) 3529{ 3530 zio_t *lio = zio->io_logical; 3531 zio_t *pio = zio_unique_parent(zio); 3532 vdev_t *vd = zio->io_vd; 3533 int flags = METASLAB_ASYNC_ALLOC; 3534 3535 ASSERT3P(zio->io_bp, !=, NULL); 3536 ASSERT3U(zio->io_type, ==, ZIO_TYPE_WRITE); 3537 ASSERT3U(zio->io_priority, ==, ZIO_PRIORITY_ASYNC_WRITE); 3538 ASSERT3U(zio->io_child_type, ==, ZIO_CHILD_VDEV); 3539 ASSERT(vd != NULL); 3540 ASSERT3P(vd, ==, vd->vdev_top); 3541 ASSERT(!(zio->io_flags & (ZIO_FLAG_IO_REPAIR | ZIO_FLAG_IO_RETRY))); 3542 ASSERT(zio->io_flags & ZIO_FLAG_IO_ALLOCATING); 3543 ASSERT(!(lio->io_flags & ZIO_FLAG_IO_REWRITE)); 3544 ASSERT(!(lio->io_orig_flags & ZIO_FLAG_NODATA)); 3545 3546 /* 3547 * Parents of gang children can have two flavors -- ones that 3548 * allocated the gang header (will have ZIO_FLAG_IO_REWRITE set) 3549 * and ones that allocated the constituent blocks. The allocation 3550 * throttle needs to know the allocating parent zio so we must find 3551 * it here. 3552 */ 3553 if (pio->io_child_type == ZIO_CHILD_GANG) { 3554 /* 3555 * If our parent is a rewrite gang child then our grandparent 3556 * would have been the one that performed the allocation. 3557 */ 3558 if (pio->io_flags & ZIO_FLAG_IO_REWRITE) 3559 pio = zio_unique_parent(pio); 3560 flags |= METASLAB_GANG_CHILD; 3561 } 3562 3563 ASSERT(IO_IS_ALLOCATING(pio)); 3564 ASSERT3P(zio, !=, zio->io_logical); 3565 ASSERT(zio->io_logical != NULL); 3566 ASSERT(!(zio->io_flags & ZIO_FLAG_IO_REPAIR)); 3567 ASSERT0(zio->io_flags & ZIO_FLAG_NOPWRITE); 3568 3569 mutex_enter(&pio->io_lock); 3570 metaslab_group_alloc_decrement(zio->io_spa, vd->vdev_id, pio, flags); 3571 mutex_exit(&pio->io_lock); 3572 3573 metaslab_class_throttle_unreserve(spa_normal_class(zio->io_spa), 3574 1, pio); 3575 3576 /* 3577 * Call into the pipeline to see if there is more work that 3578 * needs to be done. If there is work to be done it will be 3579 * dispatched to another taskq thread. 3580 */ 3581 zio_allocate_dispatch(zio->io_spa); 3582} 3583 3584static int 3585zio_done(zio_t *zio) 3586{ 3587 spa_t *spa = zio->io_spa; 3588 zio_t *lio = zio->io_logical; 3589 blkptr_t *bp = zio->io_bp; 3590 vdev_t *vd = zio->io_vd; 3591 uint64_t psize = zio->io_size; 3592 zio_t *pio, *pio_next; 3593 metaslab_class_t *mc = spa_normal_class(spa); 3594 zio_link_t *zl = NULL; 3595 3596 /* 3597 * If our children haven't all completed, 3598 * wait for them and then repeat this pipeline stage. 3599 */ 3600 if (zio_wait_for_children(zio, ZIO_CHILD_VDEV, ZIO_WAIT_DONE) || 3601 zio_wait_for_children(zio, ZIO_CHILD_GANG, ZIO_WAIT_DONE) || 3602 zio_wait_for_children(zio, ZIO_CHILD_DDT, ZIO_WAIT_DONE) || 3603 zio_wait_for_children(zio, ZIO_CHILD_LOGICAL, ZIO_WAIT_DONE)) 3604 return (ZIO_PIPELINE_STOP); 3605 3606 /* 3607 * If the allocation throttle is enabled, then update the accounting. 3608 * We only track child I/Os that are part of an allocating async 3609 * write. We must do this since the allocation is performed 3610 * by the logical I/O but the actual write is done by child I/Os. 3611 */ 3612 if (zio->io_flags & ZIO_FLAG_IO_ALLOCATING && 3613 zio->io_child_type == ZIO_CHILD_VDEV) { 3614 ASSERT(mc->mc_alloc_throttle_enabled); 3615 zio_dva_throttle_done(zio); 3616 } 3617 3618 /* 3619 * If the allocation throttle is enabled, verify that 3620 * we have decremented the refcounts for every I/O that was throttled. 3621 */ 3622 if (zio->io_flags & ZIO_FLAG_IO_ALLOCATING) { 3623 ASSERT(zio->io_type == ZIO_TYPE_WRITE); 3624 ASSERT(zio->io_priority == ZIO_PRIORITY_ASYNC_WRITE); 3625 ASSERT(bp != NULL); 3626 metaslab_group_alloc_verify(spa, zio->io_bp, zio); 3627 VERIFY(refcount_not_held(&mc->mc_alloc_slots, zio)); 3628 } 3629 3630 for (int c = 0; c < ZIO_CHILD_TYPES; c++) 3631 for (int w = 0; w < ZIO_WAIT_TYPES; w++) 3632 ASSERT(zio->io_children[c][w] == 0); 3633 3634 if (bp != NULL && !BP_IS_EMBEDDED(bp)) { 3635 ASSERT(bp->blk_pad[0] == 0); 3636 ASSERT(bp->blk_pad[1] == 0); 3637 ASSERT(bcmp(bp, &zio->io_bp_copy, sizeof (blkptr_t)) == 0 || 3638 (bp == zio_unique_parent(zio)->io_bp)); 3639 if (zio->io_type == ZIO_TYPE_WRITE && !BP_IS_HOLE(bp) && 3640 zio->io_bp_override == NULL && 3641 !(zio->io_flags & ZIO_FLAG_IO_REPAIR)) { 3642 ASSERT(!BP_SHOULD_BYTESWAP(bp)); 3643 ASSERT3U(zio->io_prop.zp_copies, <=, BP_GET_NDVAS(bp)); 3644 ASSERT(BP_COUNT_GANG(bp) == 0 || 3645 (BP_COUNT_GANG(bp) == BP_GET_NDVAS(bp))); 3646 } 3647 if (zio->io_flags & ZIO_FLAG_NOPWRITE) 3648 VERIFY(BP_EQUAL(bp, &zio->io_bp_orig)); 3649 } 3650 3651 /* 3652 * If there were child vdev/gang/ddt errors, they apply to us now. 3653 */ 3654 zio_inherit_child_errors(zio, ZIO_CHILD_VDEV); 3655 zio_inherit_child_errors(zio, ZIO_CHILD_GANG); 3656 zio_inherit_child_errors(zio, ZIO_CHILD_DDT); 3657 3658 /* 3659 * If the I/O on the transformed data was successful, generate any 3660 * checksum reports now while we still have the transformed data. 3661 */ 3662 if (zio->io_error == 0) { 3663 while (zio->io_cksum_report != NULL) { 3664 zio_cksum_report_t *zcr = zio->io_cksum_report; 3665 uint64_t align = zcr->zcr_align; 3666 uint64_t asize = P2ROUNDUP(psize, align); 3667 char *abuf = zio->io_data; 3668 3669 if (asize != psize) { 3670 abuf = zio_buf_alloc(asize); 3671 bcopy(zio->io_data, abuf, psize); 3672 bzero(abuf + psize, asize - psize); 3673 } 3674 3675 zio->io_cksum_report = zcr->zcr_next; 3676 zcr->zcr_next = NULL; 3677 zcr->zcr_finish(zcr, abuf); 3678 zfs_ereport_free_checksum(zcr); 3679 3680 if (asize != psize) 3681 zio_buf_free(abuf, asize); 3682 } 3683 } 3684 3685 zio_pop_transforms(zio); /* note: may set zio->io_error */ 3686 3687 vdev_stat_update(zio, psize); 3688 3689 if (zio->io_error) { 3690 /* 3691 * If this I/O is attached to a particular vdev, 3692 * generate an error message describing the I/O failure 3693 * at the block level. We ignore these errors if the 3694 * device is currently unavailable. 3695 */ 3696 if (zio->io_error != ECKSUM && vd != NULL && !vdev_is_dead(vd)) 3697 zfs_ereport_post(FM_EREPORT_ZFS_IO, spa, vd, zio, 0, 0); 3698 3699 if ((zio->io_error == EIO || !(zio->io_flags & 3700 (ZIO_FLAG_SPECULATIVE | ZIO_FLAG_DONT_PROPAGATE))) && 3701 zio == lio) { 3702 /* 3703 * For logical I/O requests, tell the SPA to log the 3704 * error and generate a logical data ereport. 3705 */ 3706 spa_log_error(spa, zio); 3707 zfs_ereport_post(FM_EREPORT_ZFS_DATA, spa, NULL, zio, 3708 0, 0); 3709 } 3710 } 3711 3712 if (zio->io_error && zio == lio) { 3713 /* 3714 * Determine whether zio should be reexecuted. This will 3715 * propagate all the way to the root via zio_notify_parent(). 3716 */ 3717 ASSERT(vd == NULL && bp != NULL); 3718 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL); 3719 3720 if (IO_IS_ALLOCATING(zio) && 3721 !(zio->io_flags & ZIO_FLAG_CANFAIL)) { 3722 if (zio->io_error != ENOSPC) 3723 zio->io_reexecute |= ZIO_REEXECUTE_NOW; 3724 else 3725 zio->io_reexecute |= ZIO_REEXECUTE_SUSPEND; 3726 } 3727 3728 if ((zio->io_type == ZIO_TYPE_READ || 3729 zio->io_type == ZIO_TYPE_FREE) && 3730 !(zio->io_flags & ZIO_FLAG_SCAN_THREAD) && 3731 zio->io_error == ENXIO && 3732 spa_load_state(spa) == SPA_LOAD_NONE && 3733 spa_get_failmode(spa) != ZIO_FAILURE_MODE_CONTINUE) 3734 zio->io_reexecute |= ZIO_REEXECUTE_SUSPEND; 3735 3736 if (!(zio->io_flags & ZIO_FLAG_CANFAIL) && !zio->io_reexecute) 3737 zio->io_reexecute |= ZIO_REEXECUTE_SUSPEND; 3738 3739 /* 3740 * Here is a possibly good place to attempt to do 3741 * either combinatorial reconstruction or error correction 3742 * based on checksums. It also might be a good place 3743 * to send out preliminary ereports before we suspend 3744 * processing. 3745 */ 3746 } 3747 3748 /* 3749 * If there were logical child errors, they apply to us now. 3750 * We defer this until now to avoid conflating logical child 3751 * errors with errors that happened to the zio itself when 3752 * updating vdev stats and reporting FMA events above. 3753 */ 3754 zio_inherit_child_errors(zio, ZIO_CHILD_LOGICAL); 3755 3756 if ((zio->io_error || zio->io_reexecute) && 3757 IO_IS_ALLOCATING(zio) && zio->io_gang_leader == zio && 3758 !(zio->io_flags & (ZIO_FLAG_IO_REWRITE | ZIO_FLAG_NOPWRITE))) 3759 zio_dva_unallocate(zio, zio->io_gang_tree, bp); 3760 3761 zio_gang_tree_free(&zio->io_gang_tree); 3762 3763 /* 3764 * Godfather I/Os should never suspend. 3765 */ 3766 if ((zio->io_flags & ZIO_FLAG_GODFATHER) && 3767 (zio->io_reexecute & ZIO_REEXECUTE_SUSPEND)) 3768 zio->io_reexecute = 0; 3769 3770 if (zio->io_reexecute) { 3771 /* 3772 * This is a logical I/O that wants to reexecute. 3773 * 3774 * Reexecute is top-down. When an i/o fails, if it's not 3775 * the root, it simply notifies its parent and sticks around. 3776 * The parent, seeing that it still has children in zio_done(), 3777 * does the same. This percolates all the way up to the root. 3778 * The root i/o will reexecute or suspend the entire tree. 3779 * 3780 * This approach ensures that zio_reexecute() honors 3781 * all the original i/o dependency relationships, e.g. 3782 * parents not executing until children are ready. 3783 */ 3784 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL); 3785 3786 zio->io_gang_leader = NULL; 3787 3788 mutex_enter(&zio->io_lock); 3789 zio->io_state[ZIO_WAIT_DONE] = 1; 3790 mutex_exit(&zio->io_lock); 3791 3792 /* 3793 * "The Godfather" I/O monitors its children but is 3794 * not a true parent to them. It will track them through 3795 * the pipeline but severs its ties whenever they get into 3796 * trouble (e.g. suspended). This allows "The Godfather" 3797 * I/O to return status without blocking. 3798 */ 3799 zl = NULL; 3800 for (pio = zio_walk_parents(zio, &zl); pio != NULL; 3801 pio = pio_next) { 3802 zio_link_t *remove_zl = zl; 3803 pio_next = zio_walk_parents(zio, &zl); 3804 3805 if ((pio->io_flags & ZIO_FLAG_GODFATHER) && 3806 (zio->io_reexecute & ZIO_REEXECUTE_SUSPEND)) { 3807 zio_remove_child(pio, zio, remove_zl); 3808 zio_notify_parent(pio, zio, ZIO_WAIT_DONE); 3809 } 3810 } 3811 3812 if ((pio = zio_unique_parent(zio)) != NULL) { 3813 /* 3814 * We're not a root i/o, so there's nothing to do 3815 * but notify our parent. Don't propagate errors 3816 * upward since we haven't permanently failed yet. 3817 */ 3818 ASSERT(!(zio->io_flags & ZIO_FLAG_GODFATHER)); 3819 zio->io_flags |= ZIO_FLAG_DONT_PROPAGATE; 3820 zio_notify_parent(pio, zio, ZIO_WAIT_DONE); 3821 } else if (zio->io_reexecute & ZIO_REEXECUTE_SUSPEND) { 3822 /* 3823 * We'd fail again if we reexecuted now, so suspend 3824 * until conditions improve (e.g. device comes online). 3825 */ 3826 zio_suspend(spa, zio); 3827 } else { 3828 /* 3829 * Reexecution is potentially a huge amount of work. 3830 * Hand it off to the otherwise-unused claim taskq. 3831 */ 3832#if defined(illumos) || !defined(_KERNEL) 3833 ASSERT(zio->io_tqent.tqent_next == NULL); 3834#else 3835 ASSERT(zio->io_tqent.tqent_task.ta_pending == 0); 3836#endif 3837 spa_taskq_dispatch_ent(spa, ZIO_TYPE_CLAIM, 3838 ZIO_TASKQ_ISSUE, (task_func_t *)zio_reexecute, zio, 3839 0, &zio->io_tqent); 3840 } 3841 return (ZIO_PIPELINE_STOP); 3842 } 3843 3844 ASSERT(zio->io_child_count == 0); 3845 ASSERT(zio->io_reexecute == 0); 3846 ASSERT(zio->io_error == 0 || (zio->io_flags & ZIO_FLAG_CANFAIL)); 3847 3848 /* 3849 * Report any checksum errors, since the I/O is complete. 3850 */ 3851 while (zio->io_cksum_report != NULL) { 3852 zio_cksum_report_t *zcr = zio->io_cksum_report; 3853 zio->io_cksum_report = zcr->zcr_next; 3854 zcr->zcr_next = NULL; 3855 zcr->zcr_finish(zcr, NULL); 3856 zfs_ereport_free_checksum(zcr); 3857 } 3858 3859 /* 3860 * It is the responsibility of the done callback to ensure that this 3861 * particular zio is no longer discoverable for adoption, and as 3862 * such, cannot acquire any new parents. 3863 */ 3864 if (zio->io_done) 3865 zio->io_done(zio); 3866 3867 mutex_enter(&zio->io_lock); 3868 zio->io_state[ZIO_WAIT_DONE] = 1; 3869 mutex_exit(&zio->io_lock); 3870 3871 zl = NULL; 3872 for (pio = zio_walk_parents(zio, &zl); pio != NULL; pio = pio_next) { 3873 zio_link_t *remove_zl = zl; 3874 pio_next = zio_walk_parents(zio, &zl); 3875 zio_remove_child(pio, zio, remove_zl); 3876 zio_notify_parent(pio, zio, ZIO_WAIT_DONE); 3877 } 3878 3879 if (zio->io_waiter != NULL) { 3880 mutex_enter(&zio->io_lock); 3881 zio->io_executor = NULL; 3882 cv_broadcast(&zio->io_cv); 3883 mutex_exit(&zio->io_lock); 3884 } else { 3885 zio_destroy(zio); 3886 } 3887 3888 return (ZIO_PIPELINE_STOP); 3889} 3890 3891/* 3892 * ========================================================================== 3893 * I/O pipeline definition 3894 * ========================================================================== 3895 */ 3896static zio_pipe_stage_t *zio_pipeline[] = { 3897 NULL, 3898 zio_read_bp_init, 3899 zio_write_bp_init, 3900 zio_free_bp_init, 3901 zio_issue_async, 3902 zio_write_compress, 3903 zio_checksum_generate, 3904 zio_nop_write, 3905 zio_ddt_read_start, 3906 zio_ddt_read_done, 3907 zio_ddt_write, 3908 zio_ddt_free, 3909 zio_gang_assemble, 3910 zio_gang_issue, 3911 zio_dva_throttle, 3912 zio_dva_allocate, 3913 zio_dva_free, 3914 zio_dva_claim, 3915 zio_ready, 3916 zio_vdev_io_start, 3917 zio_vdev_io_done, 3918 zio_vdev_io_assess, 3919 zio_checksum_verify, 3920 zio_done 3921}; 3922 3923 3924 3925 3926/* 3927 * Compare two zbookmark_phys_t's to see which we would reach first in a 3928 * pre-order traversal of the object tree. 3929 * 3930 * This is simple in every case aside from the meta-dnode object. For all other 3931 * objects, we traverse them in order (object 1 before object 2, and so on). 3932 * However, all of these objects are traversed while traversing object 0, since 3933 * the data it points to is the list of objects. Thus, we need to convert to a 3934 * canonical representation so we can compare meta-dnode bookmarks to 3935 * non-meta-dnode bookmarks. 3936 * 3937 * We do this by calculating "equivalents" for each field of the zbookmark. 3938 * zbookmarks outside of the meta-dnode use their own object and level, and 3939 * calculate the level 0 equivalent (the first L0 blkid that is contained in the 3940 * blocks this bookmark refers to) by multiplying their blkid by their span 3941 * (the number of L0 blocks contained within one block at their level). 3942 * zbookmarks inside the meta-dnode calculate their object equivalent 3943 * (which is L0equiv * dnodes per data block), use 0 for their L0equiv, and use 3944 * level + 1<<31 (any value larger than a level could ever be) for their level. 3945 * This causes them to always compare before a bookmark in their object 3946 * equivalent, compare appropriately to bookmarks in other objects, and to 3947 * compare appropriately to other bookmarks in the meta-dnode. 3948 */ 3949int 3950zbookmark_compare(uint16_t dbss1, uint8_t ibs1, uint16_t dbss2, uint8_t ibs2, 3951 const zbookmark_phys_t *zb1, const zbookmark_phys_t *zb2) 3952{ 3953 /* 3954 * These variables represent the "equivalent" values for the zbookmark, 3955 * after converting zbookmarks inside the meta dnode to their 3956 * normal-object equivalents. 3957 */ 3958 uint64_t zb1obj, zb2obj; 3959 uint64_t zb1L0, zb2L0; 3960 uint64_t zb1level, zb2level; 3961 3962 if (zb1->zb_object == zb2->zb_object && 3963 zb1->zb_level == zb2->zb_level && 3964 zb1->zb_blkid == zb2->zb_blkid) 3965 return (0); 3966 3967 /* 3968 * BP_SPANB calculates the span in blocks. 3969 */ 3970 zb1L0 = (zb1->zb_blkid) * BP_SPANB(ibs1, zb1->zb_level); 3971 zb2L0 = (zb2->zb_blkid) * BP_SPANB(ibs2, zb2->zb_level); 3972 3973 if (zb1->zb_object == DMU_META_DNODE_OBJECT) { 3974 zb1obj = zb1L0 * (dbss1 << (SPA_MINBLOCKSHIFT - DNODE_SHIFT)); 3975 zb1L0 = 0; 3976 zb1level = zb1->zb_level + COMPARE_META_LEVEL; 3977 } else { 3978 zb1obj = zb1->zb_object; 3979 zb1level = zb1->zb_level; 3980 } 3981 3982 if (zb2->zb_object == DMU_META_DNODE_OBJECT) { 3983 zb2obj = zb2L0 * (dbss2 << (SPA_MINBLOCKSHIFT - DNODE_SHIFT)); 3984 zb2L0 = 0; 3985 zb2level = zb2->zb_level + COMPARE_META_LEVEL; 3986 } else { 3987 zb2obj = zb2->zb_object; 3988 zb2level = zb2->zb_level; 3989 } 3990 3991 /* Now that we have a canonical representation, do the comparison. */ 3992 if (zb1obj != zb2obj) 3993 return (zb1obj < zb2obj ? -1 : 1); 3994 else if (zb1L0 != zb2L0) 3995 return (zb1L0 < zb2L0 ? -1 : 1); 3996 else if (zb1level != zb2level) 3997 return (zb1level > zb2level ? -1 : 1); 3998 /* 3999 * This can (theoretically) happen if the bookmarks have the same object 4000 * and level, but different blkids, if the block sizes are not the same. 4001 * There is presently no way to change the indirect block sizes 4002 */ 4003 return (0); 4004} 4005 4006/* 4007 * This function checks the following: given that last_block is the place that 4008 * our traversal stopped last time, does that guarantee that we've visited 4009 * every node under subtree_root? Therefore, we can't just use the raw output 4010 * of zbookmark_compare. We have to pass in a modified version of 4011 * subtree_root; by incrementing the block id, and then checking whether 4012 * last_block is before or equal to that, we can tell whether or not having 4013 * visited last_block implies that all of subtree_root's children have been 4014 * visited. 4015 */ 4016boolean_t 4017zbookmark_subtree_completed(const dnode_phys_t *dnp, 4018 const zbookmark_phys_t *subtree_root, const zbookmark_phys_t *last_block) 4019{ 4020 zbookmark_phys_t mod_zb = *subtree_root; 4021 mod_zb.zb_blkid++; 4022 ASSERT(last_block->zb_level == 0); 4023 4024 /* The objset_phys_t isn't before anything. */ 4025 if (dnp == NULL) 4026 return (B_FALSE); 4027 4028 /* 4029 * We pass in 1ULL << (DNODE_BLOCK_SHIFT - SPA_MINBLOCKSHIFT) for the 4030 * data block size in sectors, because that variable is only used if 4031 * the bookmark refers to a block in the meta-dnode. Since we don't 4032 * know without examining it what object it refers to, and there's no 4033 * harm in passing in this value in other cases, we always pass it in. 4034 * 4035 * We pass in 0 for the indirect block size shift because zb2 must be 4036 * level 0. The indirect block size is only used to calculate the span 4037 * of the bookmark, but since the bookmark must be level 0, the span is 4038 * always 1, so the math works out. 4039 * 4040 * If you make changes to how the zbookmark_compare code works, be sure 4041 * to make sure that this code still works afterwards. 4042 */ 4043 return (zbookmark_compare(dnp->dn_datablkszsec, dnp->dn_indblkshift, 4044 1ULL << (DNODE_BLOCK_SHIFT - SPA_MINBLOCKSHIFT), 0, &mod_zb, 4045 last_block) <= 0); 4046} 4047