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) 2008, 2010, Oracle and/or its affiliates. All rights reserved. 23 * Copyright (c) 2011, 2021 by Delphix. All rights reserved. 24 * Copyright 2016 Gary Mills 25 * Copyright (c) 2017, 2019, Datto Inc. All rights reserved. 26 * Copyright (c) 2015, Nexenta Systems, Inc. All rights reserved. 27 * Copyright 2019 Joyent, Inc. 28 */ 29 30 #include <sys/dsl_scan.h> 31 #include <sys/dsl_pool.h> 32 #include <sys/dsl_dataset.h> 33 #include <sys/dsl_prop.h> 34 #include <sys/dsl_dir.h> 35 #include <sys/dsl_synctask.h> 36 #include <sys/dnode.h> 37 #include <sys/dmu_tx.h> 38 #include <sys/dmu_objset.h> 39 #include <sys/arc.h> 40 #include <sys/zap.h> 41 #include <sys/zio.h> 42 #include <sys/zfs_context.h> 43 #include <sys/fs/zfs.h> 44 #include <sys/zfs_znode.h> 45 #include <sys/spa_impl.h> 46 #include <sys/vdev_impl.h> 47 #include <sys/zil_impl.h> 48 #include <sys/zio_checksum.h> 49 #include <sys/ddt.h> 50 #include <sys/sa.h> 51 #include <sys/sa_impl.h> 52 #include <sys/zfeature.h> 53 #include <sys/abd.h> 54 #include <sys/range_tree.h> 55 #ifdef _KERNEL 56 #include <sys/zfs_vfsops.h> 57 #endif 58 59 /* 60 * Grand theory statement on scan queue sorting 61 * 62 * Scanning is implemented by recursively traversing all indirection levels 63 * in an object and reading all blocks referenced from said objects. This 64 * results in us approximately traversing the object from lowest logical 65 * offset to the highest. For best performance, we would want the logical 66 * blocks to be physically contiguous. However, this is frequently not the 67 * case with pools given the allocation patterns of copy-on-write filesystems. 68 * So instead, we put the I/Os into a reordering queue and issue them in a 69 * way that will most benefit physical disks (LBA-order). 70 * 71 * Queue management: 72 * 73 * Ideally, we would want to scan all metadata and queue up all block I/O 74 * prior to starting to issue it, because that allows us to do an optimal 75 * sorting job. This can however consume large amounts of memory. Therefore 76 * we continuously monitor the size of the queues and constrain them to 5% 77 * (zfs_scan_mem_lim_fact) of physmem. If the queues grow larger than this 78 * limit, we clear out a few of the largest extents at the head of the queues 79 * to make room for more scanning. Hopefully, these extents will be fairly 80 * large and contiguous, allowing us to approach sequential I/O throughput 81 * even without a fully sorted tree. 82 * 83 * Metadata scanning takes place in dsl_scan_visit(), which is called from 84 * dsl_scan_sync() every spa_sync(). If we have either fully scanned all 85 * metadata on the pool, or we need to make room in memory because our 86 * queues are too large, dsl_scan_visit() is postponed and 87 * scan_io_queues_run() is called from dsl_scan_sync() instead. This implies 88 * that metadata scanning and queued I/O issuing are mutually exclusive. This 89 * allows us to provide maximum sequential I/O throughput for the majority of 90 * I/O's issued since sequential I/O performance is significantly negatively 91 * impacted if it is interleaved with random I/O. 92 * 93 * Implementation Notes 94 * 95 * One side effect of the queued scanning algorithm is that the scanning code 96 * needs to be notified whenever a block is freed. This is needed to allow 97 * the scanning code to remove these I/Os from the issuing queue. Additionally, 98 * we do not attempt to queue gang blocks to be issued sequentially since this 99 * is very hard to do and would have an extremely limited performance benefit. 100 * Instead, we simply issue gang I/Os as soon as we find them using the legacy 101 * algorithm. 102 * 103 * Backwards compatibility 104 * 105 * This new algorithm is backwards compatible with the legacy on-disk data 106 * structures (and therefore does not require a new feature flag). 107 * Periodically during scanning (see zfs_scan_checkpoint_intval), the scan 108 * will stop scanning metadata (in logical order) and wait for all outstanding 109 * sorted I/O to complete. Once this is done, we write out a checkpoint 110 * bookmark, indicating that we have scanned everything logically before it. 111 * If the pool is imported on a machine without the new sorting algorithm, 112 * the scan simply resumes from the last checkpoint using the legacy algorithm. 113 */ 114 115 typedef int (scan_cb_t)(dsl_pool_t *, const blkptr_t *, 116 const zbookmark_phys_t *); 117 118 static scan_cb_t dsl_scan_scrub_cb; 119 120 static int scan_ds_queue_compare(const void *a, const void *b); 121 static int scan_prefetch_queue_compare(const void *a, const void *b); 122 static void scan_ds_queue_clear(dsl_scan_t *scn); 123 static void scan_ds_prefetch_queue_clear(dsl_scan_t *scn); 124 static boolean_t scan_ds_queue_contains(dsl_scan_t *scn, uint64_t dsobj, 125 uint64_t *txg); 126 static void scan_ds_queue_insert(dsl_scan_t *scn, uint64_t dsobj, uint64_t txg); 127 static void scan_ds_queue_remove(dsl_scan_t *scn, uint64_t dsobj); 128 static void scan_ds_queue_sync(dsl_scan_t *scn, dmu_tx_t *tx); 129 static uint64_t dsl_scan_count_data_disks(vdev_t *vd); 130 131 extern int zfs_vdev_async_write_active_min_dirty_percent; 132 133 /* 134 * By default zfs will check to ensure it is not over the hard memory 135 * limit before each txg. If finer-grained control of this is needed 136 * this value can be set to 1 to enable checking before scanning each 137 * block. 138 */ 139 static int zfs_scan_strict_mem_lim = B_FALSE; 140 141 /* 142 * Maximum number of parallelly executed bytes per leaf vdev. We attempt 143 * to strike a balance here between keeping the vdev queues full of I/Os 144 * at all times and not overflowing the queues to cause long latency, 145 * which would cause long txg sync times. No matter what, we will not 146 * overload the drives with I/O, since that is protected by 147 * zfs_vdev_scrub_max_active. 148 */ 149 static unsigned long zfs_scan_vdev_limit = 4 << 20; 150 151 static int zfs_scan_issue_strategy = 0; 152 static int zfs_scan_legacy = B_FALSE; /* don't queue & sort zios, go direct */ 153 static unsigned long zfs_scan_max_ext_gap = 2 << 20; /* in bytes */ 154 155 /* 156 * fill_weight is non-tunable at runtime, so we copy it at module init from 157 * zfs_scan_fill_weight. Runtime adjustments to zfs_scan_fill_weight would 158 * break queue sorting. 159 */ 160 static int zfs_scan_fill_weight = 3; 161 static uint64_t fill_weight; 162 163 /* See dsl_scan_should_clear() for details on the memory limit tunables */ 164 static const uint64_t zfs_scan_mem_lim_min = 16 << 20; /* bytes */ 165 static const uint64_t zfs_scan_mem_lim_soft_max = 128 << 20; /* bytes */ 166 static int zfs_scan_mem_lim_fact = 20; /* fraction of physmem */ 167 static int zfs_scan_mem_lim_soft_fact = 20; /* fraction of mem lim above */ 168 169 static int zfs_scrub_min_time_ms = 1000; /* min millis to scrub per txg */ 170 static int zfs_obsolete_min_time_ms = 500; /* min millis to obsolete per txg */ 171 static int zfs_free_min_time_ms = 1000; /* min millis to free per txg */ 172 static int zfs_resilver_min_time_ms = 3000; /* min millis to resilver per txg */ 173 static int zfs_scan_checkpoint_intval = 7200; /* in seconds */ 174 int zfs_scan_suspend_progress = 0; /* set to prevent scans from progressing */ 175 static int zfs_no_scrub_io = B_FALSE; /* set to disable scrub i/o */ 176 static int zfs_no_scrub_prefetch = B_FALSE; /* set to disable scrub prefetch */ 177 static const enum ddt_class zfs_scrub_ddt_class_max = DDT_CLASS_DUPLICATE; 178 /* max number of blocks to free in a single TXG */ 179 static unsigned long zfs_async_block_max_blocks = ULONG_MAX; 180 /* max number of dedup blocks to free in a single TXG */ 181 static unsigned long zfs_max_async_dedup_frees = 100000; 182 183 /* set to disable resilver deferring */ 184 static int zfs_resilver_disable_defer = B_FALSE; 185 186 /* 187 * We wait a few txgs after importing a pool to begin scanning so that 188 * the import / mounting code isn't held up by scrub / resilver IO. 189 * Unfortunately, it is a bit difficult to determine exactly how long 190 * this will take since userspace will trigger fs mounts asynchronously 191 * and the kernel will create zvol minors asynchronously. As a result, 192 * the value provided here is a bit arbitrary, but represents a 193 * reasonable estimate of how many txgs it will take to finish fully 194 * importing a pool 195 */ 196 #define SCAN_IMPORT_WAIT_TXGS 5 197 198 #define DSL_SCAN_IS_SCRUB_RESILVER(scn) \ 199 ((scn)->scn_phys.scn_func == POOL_SCAN_SCRUB || \ 200 (scn)->scn_phys.scn_func == POOL_SCAN_RESILVER) 201 202 /* 203 * Enable/disable the processing of the free_bpobj object. 204 */ 205 static int zfs_free_bpobj_enabled = 1; 206 207 /* the order has to match pool_scan_type */ 208 static scan_cb_t *scan_funcs[POOL_SCAN_FUNCS] = { 209 NULL, 210 dsl_scan_scrub_cb, /* POOL_SCAN_SCRUB */ 211 dsl_scan_scrub_cb, /* POOL_SCAN_RESILVER */ 212 }; 213 214 /* In core node for the scn->scn_queue. Represents a dataset to be scanned */ 215 typedef struct { 216 uint64_t sds_dsobj; 217 uint64_t sds_txg; 218 avl_node_t sds_node; 219 } scan_ds_t; 220 221 /* 222 * This controls what conditions are placed on dsl_scan_sync_state(): 223 * SYNC_OPTIONAL) write out scn_phys iff scn_bytes_pending == 0 224 * SYNC_MANDATORY) write out scn_phys always. scn_bytes_pending must be 0. 225 * SYNC_CACHED) if scn_bytes_pending == 0, write out scn_phys. Otherwise 226 * write out the scn_phys_cached version. 227 * See dsl_scan_sync_state for details. 228 */ 229 typedef enum { 230 SYNC_OPTIONAL, 231 SYNC_MANDATORY, 232 SYNC_CACHED 233 } state_sync_type_t; 234 235 /* 236 * This struct represents the minimum information needed to reconstruct a 237 * zio for sequential scanning. This is useful because many of these will 238 * accumulate in the sequential IO queues before being issued, so saving 239 * memory matters here. 240 */ 241 typedef struct scan_io { 242 /* fields from blkptr_t */ 243 uint64_t sio_blk_prop; 244 uint64_t sio_phys_birth; 245 uint64_t sio_birth; 246 zio_cksum_t sio_cksum; 247 uint32_t sio_nr_dvas; 248 249 /* fields from zio_t */ 250 uint32_t sio_flags; 251 zbookmark_phys_t sio_zb; 252 253 /* members for queue sorting */ 254 union { 255 avl_node_t sio_addr_node; /* link into issuing queue */ 256 list_node_t sio_list_node; /* link for issuing to disk */ 257 } sio_nodes; 258 259 /* 260 * There may be up to SPA_DVAS_PER_BP DVAs here from the bp, 261 * depending on how many were in the original bp. Only the 262 * first DVA is really used for sorting and issuing purposes. 263 * The other DVAs (if provided) simply exist so that the zio 264 * layer can find additional copies to repair from in the 265 * event of an error. This array must go at the end of the 266 * struct to allow this for the variable number of elements. 267 */ 268 dva_t sio_dva[0]; 269 } scan_io_t; 270 271 #define SIO_SET_OFFSET(sio, x) DVA_SET_OFFSET(&(sio)->sio_dva[0], x) 272 #define SIO_SET_ASIZE(sio, x) DVA_SET_ASIZE(&(sio)->sio_dva[0], x) 273 #define SIO_GET_OFFSET(sio) DVA_GET_OFFSET(&(sio)->sio_dva[0]) 274 #define SIO_GET_ASIZE(sio) DVA_GET_ASIZE(&(sio)->sio_dva[0]) 275 #define SIO_GET_END_OFFSET(sio) \ 276 (SIO_GET_OFFSET(sio) + SIO_GET_ASIZE(sio)) 277 #define SIO_GET_MUSED(sio) \ 278 (sizeof (scan_io_t) + ((sio)->sio_nr_dvas * sizeof (dva_t))) 279 280 struct dsl_scan_io_queue { 281 dsl_scan_t *q_scn; /* associated dsl_scan_t */ 282 vdev_t *q_vd; /* top-level vdev that this queue represents */ 283 284 /* trees used for sorting I/Os and extents of I/Os */ 285 range_tree_t *q_exts_by_addr; 286 zfs_btree_t q_exts_by_size; 287 avl_tree_t q_sios_by_addr; 288 uint64_t q_sio_memused; 289 290 /* members for zio rate limiting */ 291 uint64_t q_maxinflight_bytes; 292 uint64_t q_inflight_bytes; 293 kcondvar_t q_zio_cv; /* used under vd->vdev_scan_io_queue_lock */ 294 295 /* per txg statistics */ 296 uint64_t q_total_seg_size_this_txg; 297 uint64_t q_segs_this_txg; 298 uint64_t q_total_zio_size_this_txg; 299 uint64_t q_zios_this_txg; 300 }; 301 302 /* private data for dsl_scan_prefetch_cb() */ 303 typedef struct scan_prefetch_ctx { 304 zfs_refcount_t spc_refcnt; /* refcount for memory management */ 305 dsl_scan_t *spc_scn; /* dsl_scan_t for the pool */ 306 boolean_t spc_root; /* is this prefetch for an objset? */ 307 uint8_t spc_indblkshift; /* dn_indblkshift of current dnode */ 308 uint16_t spc_datablkszsec; /* dn_idatablkszsec of current dnode */ 309 } scan_prefetch_ctx_t; 310 311 /* private data for dsl_scan_prefetch() */ 312 typedef struct scan_prefetch_issue_ctx { 313 avl_node_t spic_avl_node; /* link into scn->scn_prefetch_queue */ 314 scan_prefetch_ctx_t *spic_spc; /* spc for the callback */ 315 blkptr_t spic_bp; /* bp to prefetch */ 316 zbookmark_phys_t spic_zb; /* bookmark to prefetch */ 317 } scan_prefetch_issue_ctx_t; 318 319 static void scan_exec_io(dsl_pool_t *dp, const blkptr_t *bp, int zio_flags, 320 const zbookmark_phys_t *zb, dsl_scan_io_queue_t *queue); 321 static void scan_io_queue_insert_impl(dsl_scan_io_queue_t *queue, 322 scan_io_t *sio); 323 324 static dsl_scan_io_queue_t *scan_io_queue_create(vdev_t *vd); 325 static void scan_io_queues_destroy(dsl_scan_t *scn); 326 327 static kmem_cache_t *sio_cache[SPA_DVAS_PER_BP]; 328 329 /* sio->sio_nr_dvas must be set so we know which cache to free from */ 330 static void 331 sio_free(scan_io_t *sio) 332 { 333 ASSERT3U(sio->sio_nr_dvas, >, 0); 334 ASSERT3U(sio->sio_nr_dvas, <=, SPA_DVAS_PER_BP); 335 336 kmem_cache_free(sio_cache[sio->sio_nr_dvas - 1], sio); 337 } 338 339 /* It is up to the caller to set sio->sio_nr_dvas for freeing */ 340 static scan_io_t * 341 sio_alloc(unsigned short nr_dvas) 342 { 343 ASSERT3U(nr_dvas, >, 0); 344 ASSERT3U(nr_dvas, <=, SPA_DVAS_PER_BP); 345 346 return (kmem_cache_alloc(sio_cache[nr_dvas - 1], KM_SLEEP)); 347 } 348 349 void 350 scan_init(void) 351 { 352 /* 353 * This is used in ext_size_compare() to weight segments 354 * based on how sparse they are. This cannot be changed 355 * mid-scan and the tree comparison functions don't currently 356 * have a mechanism for passing additional context to the 357 * compare functions. Thus we store this value globally and 358 * we only allow it to be set at module initialization time 359 */ 360 fill_weight = zfs_scan_fill_weight; 361 362 for (int i = 0; i < SPA_DVAS_PER_BP; i++) { 363 char name[36]; 364 365 (void) snprintf(name, sizeof (name), "sio_cache_%d", i); 366 sio_cache[i] = kmem_cache_create(name, 367 (sizeof (scan_io_t) + ((i + 1) * sizeof (dva_t))), 368 0, NULL, NULL, NULL, NULL, NULL, 0); 369 } 370 } 371 372 void 373 scan_fini(void) 374 { 375 for (int i = 0; i < SPA_DVAS_PER_BP; i++) { 376 kmem_cache_destroy(sio_cache[i]); 377 } 378 } 379 380 static inline boolean_t 381 dsl_scan_is_running(const dsl_scan_t *scn) 382 { 383 return (scn->scn_phys.scn_state == DSS_SCANNING); 384 } 385 386 boolean_t 387 dsl_scan_resilvering(dsl_pool_t *dp) 388 { 389 return (dsl_scan_is_running(dp->dp_scan) && 390 dp->dp_scan->scn_phys.scn_func == POOL_SCAN_RESILVER); 391 } 392 393 static inline void 394 sio2bp(const scan_io_t *sio, blkptr_t *bp) 395 { 396 memset(bp, 0, sizeof (*bp)); 397 bp->blk_prop = sio->sio_blk_prop; 398 bp->blk_phys_birth = sio->sio_phys_birth; 399 bp->blk_birth = sio->sio_birth; 400 bp->blk_fill = 1; /* we always only work with data pointers */ 401 bp->blk_cksum = sio->sio_cksum; 402 403 ASSERT3U(sio->sio_nr_dvas, >, 0); 404 ASSERT3U(sio->sio_nr_dvas, <=, SPA_DVAS_PER_BP); 405 406 memcpy(bp->blk_dva, sio->sio_dva, sio->sio_nr_dvas * sizeof (dva_t)); 407 } 408 409 static inline void 410 bp2sio(const blkptr_t *bp, scan_io_t *sio, int dva_i) 411 { 412 sio->sio_blk_prop = bp->blk_prop; 413 sio->sio_phys_birth = bp->blk_phys_birth; 414 sio->sio_birth = bp->blk_birth; 415 sio->sio_cksum = bp->blk_cksum; 416 sio->sio_nr_dvas = BP_GET_NDVAS(bp); 417 418 /* 419 * Copy the DVAs to the sio. We need all copies of the block so 420 * that the self healing code can use the alternate copies if the 421 * first is corrupted. We want the DVA at index dva_i to be first 422 * in the sio since this is the primary one that we want to issue. 423 */ 424 for (int i = 0, j = dva_i; i < sio->sio_nr_dvas; i++, j++) { 425 sio->sio_dva[i] = bp->blk_dva[j % sio->sio_nr_dvas]; 426 } 427 } 428 429 int 430 dsl_scan_init(dsl_pool_t *dp, uint64_t txg) 431 { 432 int err; 433 dsl_scan_t *scn; 434 spa_t *spa = dp->dp_spa; 435 uint64_t f; 436 437 scn = dp->dp_scan = kmem_zalloc(sizeof (dsl_scan_t), KM_SLEEP); 438 scn->scn_dp = dp; 439 440 /* 441 * It's possible that we're resuming a scan after a reboot so 442 * make sure that the scan_async_destroying flag is initialized 443 * appropriately. 444 */ 445 ASSERT(!scn->scn_async_destroying); 446 scn->scn_async_destroying = spa_feature_is_active(dp->dp_spa, 447 SPA_FEATURE_ASYNC_DESTROY); 448 449 /* 450 * Calculate the max number of in-flight bytes for pool-wide 451 * scanning operations (minimum 1MB). Limits for the issuing 452 * phase are done per top-level vdev and are handled separately. 453 */ 454 scn->scn_maxinflight_bytes = MAX(zfs_scan_vdev_limit * 455 dsl_scan_count_data_disks(spa->spa_root_vdev), 1ULL << 20); 456 457 avl_create(&scn->scn_queue, scan_ds_queue_compare, sizeof (scan_ds_t), 458 offsetof(scan_ds_t, sds_node)); 459 avl_create(&scn->scn_prefetch_queue, scan_prefetch_queue_compare, 460 sizeof (scan_prefetch_issue_ctx_t), 461 offsetof(scan_prefetch_issue_ctx_t, spic_avl_node)); 462 463 err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT, 464 "scrub_func", sizeof (uint64_t), 1, &f); 465 if (err == 0) { 466 /* 467 * There was an old-style scrub in progress. Restart a 468 * new-style scrub from the beginning. 469 */ 470 scn->scn_restart_txg = txg; 471 zfs_dbgmsg("old-style scrub was in progress for %s; " 472 "restarting new-style scrub in txg %llu", 473 spa->spa_name, 474 (longlong_t)scn->scn_restart_txg); 475 476 /* 477 * Load the queue obj from the old location so that it 478 * can be freed by dsl_scan_done(). 479 */ 480 (void) zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT, 481 "scrub_queue", sizeof (uint64_t), 1, 482 &scn->scn_phys.scn_queue_obj); 483 } else { 484 err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT, 485 DMU_POOL_SCAN, sizeof (uint64_t), SCAN_PHYS_NUMINTS, 486 &scn->scn_phys); 487 /* 488 * Detect if the pool contains the signature of #2094. If it 489 * does properly update the scn->scn_phys structure and notify 490 * the administrator by setting an errata for the pool. 491 */ 492 if (err == EOVERFLOW) { 493 uint64_t zaptmp[SCAN_PHYS_NUMINTS + 1]; 494 VERIFY3S(SCAN_PHYS_NUMINTS, ==, 24); 495 VERIFY3S(offsetof(dsl_scan_phys_t, scn_flags), ==, 496 (23 * sizeof (uint64_t))); 497 498 err = zap_lookup(dp->dp_meta_objset, 499 DMU_POOL_DIRECTORY_OBJECT, DMU_POOL_SCAN, 500 sizeof (uint64_t), SCAN_PHYS_NUMINTS + 1, &zaptmp); 501 if (err == 0) { 502 uint64_t overflow = zaptmp[SCAN_PHYS_NUMINTS]; 503 504 if (overflow & ~DSL_SCAN_FLAGS_MASK || 505 scn->scn_async_destroying) { 506 spa->spa_errata = 507 ZPOOL_ERRATA_ZOL_2094_ASYNC_DESTROY; 508 return (EOVERFLOW); 509 } 510 511 memcpy(&scn->scn_phys, zaptmp, 512 SCAN_PHYS_NUMINTS * sizeof (uint64_t)); 513 scn->scn_phys.scn_flags = overflow; 514 515 /* Required scrub already in progress. */ 516 if (scn->scn_phys.scn_state == DSS_FINISHED || 517 scn->scn_phys.scn_state == DSS_CANCELED) 518 spa->spa_errata = 519 ZPOOL_ERRATA_ZOL_2094_SCRUB; 520 } 521 } 522 523 if (err == ENOENT) 524 return (0); 525 else if (err) 526 return (err); 527 528 /* 529 * We might be restarting after a reboot, so jump the issued 530 * counter to how far we've scanned. We know we're consistent 531 * up to here. 532 */ 533 scn->scn_issued_before_pass = scn->scn_phys.scn_examined; 534 535 if (dsl_scan_is_running(scn) && 536 spa_prev_software_version(dp->dp_spa) < SPA_VERSION_SCAN) { 537 /* 538 * A new-type scrub was in progress on an old 539 * pool, and the pool was accessed by old 540 * software. Restart from the beginning, since 541 * the old software may have changed the pool in 542 * the meantime. 543 */ 544 scn->scn_restart_txg = txg; 545 zfs_dbgmsg("new-style scrub for %s was modified " 546 "by old software; restarting in txg %llu", 547 spa->spa_name, 548 (longlong_t)scn->scn_restart_txg); 549 } else if (dsl_scan_resilvering(dp)) { 550 /* 551 * If a resilver is in progress and there are already 552 * errors, restart it instead of finishing this scan and 553 * then restarting it. If there haven't been any errors 554 * then remember that the incore DTL is valid. 555 */ 556 if (scn->scn_phys.scn_errors > 0) { 557 scn->scn_restart_txg = txg; 558 zfs_dbgmsg("resilver can't excise DTL_MISSING " 559 "when finished; restarting on %s in txg " 560 "%llu", 561 spa->spa_name, 562 (u_longlong_t)scn->scn_restart_txg); 563 } else { 564 /* it's safe to excise DTL when finished */ 565 spa->spa_scrub_started = B_TRUE; 566 } 567 } 568 } 569 570 memcpy(&scn->scn_phys_cached, &scn->scn_phys, sizeof (scn->scn_phys)); 571 572 /* reload the queue into the in-core state */ 573 if (scn->scn_phys.scn_queue_obj != 0) { 574 zap_cursor_t zc; 575 zap_attribute_t za; 576 577 for (zap_cursor_init(&zc, dp->dp_meta_objset, 578 scn->scn_phys.scn_queue_obj); 579 zap_cursor_retrieve(&zc, &za) == 0; 580 (void) zap_cursor_advance(&zc)) { 581 scan_ds_queue_insert(scn, 582 zfs_strtonum(za.za_name, NULL), 583 za.za_first_integer); 584 } 585 zap_cursor_fini(&zc); 586 } 587 588 spa_scan_stat_init(spa); 589 return (0); 590 } 591 592 void 593 dsl_scan_fini(dsl_pool_t *dp) 594 { 595 if (dp->dp_scan != NULL) { 596 dsl_scan_t *scn = dp->dp_scan; 597 598 if (scn->scn_taskq != NULL) 599 taskq_destroy(scn->scn_taskq); 600 601 scan_ds_queue_clear(scn); 602 avl_destroy(&scn->scn_queue); 603 scan_ds_prefetch_queue_clear(scn); 604 avl_destroy(&scn->scn_prefetch_queue); 605 606 kmem_free(dp->dp_scan, sizeof (dsl_scan_t)); 607 dp->dp_scan = NULL; 608 } 609 } 610 611 static boolean_t 612 dsl_scan_restarting(dsl_scan_t *scn, dmu_tx_t *tx) 613 { 614 return (scn->scn_restart_txg != 0 && 615 scn->scn_restart_txg <= tx->tx_txg); 616 } 617 618 boolean_t 619 dsl_scan_resilver_scheduled(dsl_pool_t *dp) 620 { 621 return ((dp->dp_scan && dp->dp_scan->scn_restart_txg != 0) || 622 (spa_async_tasks(dp->dp_spa) & SPA_ASYNC_RESILVER)); 623 } 624 625 boolean_t 626 dsl_scan_scrubbing(const dsl_pool_t *dp) 627 { 628 dsl_scan_phys_t *scn_phys = &dp->dp_scan->scn_phys; 629 630 return (scn_phys->scn_state == DSS_SCANNING && 631 scn_phys->scn_func == POOL_SCAN_SCRUB); 632 } 633 634 boolean_t 635 dsl_scan_is_paused_scrub(const dsl_scan_t *scn) 636 { 637 return (dsl_scan_scrubbing(scn->scn_dp) && 638 scn->scn_phys.scn_flags & DSF_SCRUB_PAUSED); 639 } 640 641 /* 642 * Writes out a persistent dsl_scan_phys_t record to the pool directory. 643 * Because we can be running in the block sorting algorithm, we do not always 644 * want to write out the record, only when it is "safe" to do so. This safety 645 * condition is achieved by making sure that the sorting queues are empty 646 * (scn_bytes_pending == 0). When this condition is not true, the sync'd state 647 * is inconsistent with how much actual scanning progress has been made. The 648 * kind of sync to be performed is specified by the sync_type argument. If the 649 * sync is optional, we only sync if the queues are empty. If the sync is 650 * mandatory, we do a hard ASSERT to make sure that the queues are empty. The 651 * third possible state is a "cached" sync. This is done in response to: 652 * 1) The dataset that was in the last sync'd dsl_scan_phys_t having been 653 * destroyed, so we wouldn't be able to restart scanning from it. 654 * 2) The snapshot that was in the last sync'd dsl_scan_phys_t having been 655 * superseded by a newer snapshot. 656 * 3) The dataset that was in the last sync'd dsl_scan_phys_t having been 657 * swapped with its clone. 658 * In all cases, a cached sync simply rewrites the last record we've written, 659 * just slightly modified. For the modifications that are performed to the 660 * last written dsl_scan_phys_t, see dsl_scan_ds_destroyed, 661 * dsl_scan_ds_snapshotted and dsl_scan_ds_clone_swapped. 662 */ 663 static void 664 dsl_scan_sync_state(dsl_scan_t *scn, dmu_tx_t *tx, state_sync_type_t sync_type) 665 { 666 int i; 667 spa_t *spa = scn->scn_dp->dp_spa; 668 669 ASSERT(sync_type != SYNC_MANDATORY || scn->scn_bytes_pending == 0); 670 if (scn->scn_bytes_pending == 0) { 671 for (i = 0; i < spa->spa_root_vdev->vdev_children; i++) { 672 vdev_t *vd = spa->spa_root_vdev->vdev_child[i]; 673 dsl_scan_io_queue_t *q = vd->vdev_scan_io_queue; 674 675 if (q == NULL) 676 continue; 677 678 mutex_enter(&vd->vdev_scan_io_queue_lock); 679 ASSERT3P(avl_first(&q->q_sios_by_addr), ==, NULL); 680 ASSERT3P(zfs_btree_first(&q->q_exts_by_size, NULL), ==, 681 NULL); 682 ASSERT3P(range_tree_first(q->q_exts_by_addr), ==, NULL); 683 mutex_exit(&vd->vdev_scan_io_queue_lock); 684 } 685 686 if (scn->scn_phys.scn_queue_obj != 0) 687 scan_ds_queue_sync(scn, tx); 688 VERIFY0(zap_update(scn->scn_dp->dp_meta_objset, 689 DMU_POOL_DIRECTORY_OBJECT, 690 DMU_POOL_SCAN, sizeof (uint64_t), SCAN_PHYS_NUMINTS, 691 &scn->scn_phys, tx)); 692 memcpy(&scn->scn_phys_cached, &scn->scn_phys, 693 sizeof (scn->scn_phys)); 694 695 if (scn->scn_checkpointing) 696 zfs_dbgmsg("finish scan checkpoint for %s", 697 spa->spa_name); 698 699 scn->scn_checkpointing = B_FALSE; 700 scn->scn_last_checkpoint = ddi_get_lbolt(); 701 } else if (sync_type == SYNC_CACHED) { 702 VERIFY0(zap_update(scn->scn_dp->dp_meta_objset, 703 DMU_POOL_DIRECTORY_OBJECT, 704 DMU_POOL_SCAN, sizeof (uint64_t), SCAN_PHYS_NUMINTS, 705 &scn->scn_phys_cached, tx)); 706 } 707 } 708 709 int 710 dsl_scan_setup_check(void *arg, dmu_tx_t *tx) 711 { 712 (void) arg; 713 dsl_scan_t *scn = dmu_tx_pool(tx)->dp_scan; 714 vdev_t *rvd = scn->scn_dp->dp_spa->spa_root_vdev; 715 716 if (dsl_scan_is_running(scn) || vdev_rebuild_active(rvd)) 717 return (SET_ERROR(EBUSY)); 718 719 return (0); 720 } 721 722 void 723 dsl_scan_setup_sync(void *arg, dmu_tx_t *tx) 724 { 725 dsl_scan_t *scn = dmu_tx_pool(tx)->dp_scan; 726 pool_scan_func_t *funcp = arg; 727 dmu_object_type_t ot = 0; 728 dsl_pool_t *dp = scn->scn_dp; 729 spa_t *spa = dp->dp_spa; 730 731 ASSERT(!dsl_scan_is_running(scn)); 732 ASSERT(*funcp > POOL_SCAN_NONE && *funcp < POOL_SCAN_FUNCS); 733 memset(&scn->scn_phys, 0, sizeof (scn->scn_phys)); 734 scn->scn_phys.scn_func = *funcp; 735 scn->scn_phys.scn_state = DSS_SCANNING; 736 scn->scn_phys.scn_min_txg = 0; 737 scn->scn_phys.scn_max_txg = tx->tx_txg; 738 scn->scn_phys.scn_ddt_class_max = DDT_CLASSES - 1; /* the entire DDT */ 739 scn->scn_phys.scn_start_time = gethrestime_sec(); 740 scn->scn_phys.scn_errors = 0; 741 scn->scn_phys.scn_to_examine = spa->spa_root_vdev->vdev_stat.vs_alloc; 742 scn->scn_issued_before_pass = 0; 743 scn->scn_restart_txg = 0; 744 scn->scn_done_txg = 0; 745 scn->scn_last_checkpoint = 0; 746 scn->scn_checkpointing = B_FALSE; 747 spa_scan_stat_init(spa); 748 749 if (DSL_SCAN_IS_SCRUB_RESILVER(scn)) { 750 scn->scn_phys.scn_ddt_class_max = zfs_scrub_ddt_class_max; 751 752 /* rewrite all disk labels */ 753 vdev_config_dirty(spa->spa_root_vdev); 754 755 if (vdev_resilver_needed(spa->spa_root_vdev, 756 &scn->scn_phys.scn_min_txg, &scn->scn_phys.scn_max_txg)) { 757 nvlist_t *aux = fnvlist_alloc(); 758 fnvlist_add_string(aux, ZFS_EV_RESILVER_TYPE, 759 "healing"); 760 spa_event_notify(spa, NULL, aux, 761 ESC_ZFS_RESILVER_START); 762 nvlist_free(aux); 763 } else { 764 spa_event_notify(spa, NULL, NULL, ESC_ZFS_SCRUB_START); 765 } 766 767 spa->spa_scrub_started = B_TRUE; 768 /* 769 * If this is an incremental scrub, limit the DDT scrub phase 770 * to just the auto-ditto class (for correctness); the rest 771 * of the scrub should go faster using top-down pruning. 772 */ 773 if (scn->scn_phys.scn_min_txg > TXG_INITIAL) 774 scn->scn_phys.scn_ddt_class_max = DDT_CLASS_DITTO; 775 776 /* 777 * When starting a resilver clear any existing rebuild state. 778 * This is required to prevent stale rebuild status from 779 * being reported when a rebuild is run, then a resilver and 780 * finally a scrub. In which case only the scrub status 781 * should be reported by 'zpool status'. 782 */ 783 if (scn->scn_phys.scn_func == POOL_SCAN_RESILVER) { 784 vdev_t *rvd = spa->spa_root_vdev; 785 for (uint64_t i = 0; i < rvd->vdev_children; i++) { 786 vdev_t *vd = rvd->vdev_child[i]; 787 vdev_rebuild_clear_sync( 788 (void *)(uintptr_t)vd->vdev_id, tx); 789 } 790 } 791 } 792 793 /* back to the generic stuff */ 794 795 if (dp->dp_blkstats == NULL) { 796 dp->dp_blkstats = 797 vmem_alloc(sizeof (zfs_all_blkstats_t), KM_SLEEP); 798 mutex_init(&dp->dp_blkstats->zab_lock, NULL, 799 MUTEX_DEFAULT, NULL); 800 } 801 memset(&dp->dp_blkstats->zab_type, 0, 802 sizeof (dp->dp_blkstats->zab_type)); 803 804 if (spa_version(spa) < SPA_VERSION_DSL_SCRUB) 805 ot = DMU_OT_ZAP_OTHER; 806 807 scn->scn_phys.scn_queue_obj = zap_create(dp->dp_meta_objset, 808 ot ? ot : DMU_OT_SCAN_QUEUE, DMU_OT_NONE, 0, tx); 809 810 memcpy(&scn->scn_phys_cached, &scn->scn_phys, sizeof (scn->scn_phys)); 811 812 dsl_scan_sync_state(scn, tx, SYNC_MANDATORY); 813 814 spa_history_log_internal(spa, "scan setup", tx, 815 "func=%u mintxg=%llu maxtxg=%llu", 816 *funcp, (u_longlong_t)scn->scn_phys.scn_min_txg, 817 (u_longlong_t)scn->scn_phys.scn_max_txg); 818 } 819 820 /* 821 * Called by the ZFS_IOC_POOL_SCAN ioctl to start a scrub or resilver. 822 * Can also be called to resume a paused scrub. 823 */ 824 int 825 dsl_scan(dsl_pool_t *dp, pool_scan_func_t func) 826 { 827 spa_t *spa = dp->dp_spa; 828 dsl_scan_t *scn = dp->dp_scan; 829 830 /* 831 * Purge all vdev caches and probe all devices. We do this here 832 * rather than in sync context because this requires a writer lock 833 * on the spa_config lock, which we can't do from sync context. The 834 * spa_scrub_reopen flag indicates that vdev_open() should not 835 * attempt to start another scrub. 836 */ 837 spa_vdev_state_enter(spa, SCL_NONE); 838 spa->spa_scrub_reopen = B_TRUE; 839 vdev_reopen(spa->spa_root_vdev); 840 spa->spa_scrub_reopen = B_FALSE; 841 (void) spa_vdev_state_exit(spa, NULL, 0); 842 843 if (func == POOL_SCAN_RESILVER) { 844 dsl_scan_restart_resilver(spa->spa_dsl_pool, 0); 845 return (0); 846 } 847 848 if (func == POOL_SCAN_SCRUB && dsl_scan_is_paused_scrub(scn)) { 849 /* got scrub start cmd, resume paused scrub */ 850 int err = dsl_scrub_set_pause_resume(scn->scn_dp, 851 POOL_SCRUB_NORMAL); 852 if (err == 0) { 853 spa_event_notify(spa, NULL, NULL, ESC_ZFS_SCRUB_RESUME); 854 return (SET_ERROR(ECANCELED)); 855 } 856 857 return (SET_ERROR(err)); 858 } 859 860 return (dsl_sync_task(spa_name(spa), dsl_scan_setup_check, 861 dsl_scan_setup_sync, &func, 0, ZFS_SPACE_CHECK_EXTRA_RESERVED)); 862 } 863 864 static void 865 dsl_scan_done(dsl_scan_t *scn, boolean_t complete, dmu_tx_t *tx) 866 { 867 static const char *old_names[] = { 868 "scrub_bookmark", 869 "scrub_ddt_bookmark", 870 "scrub_ddt_class_max", 871 "scrub_queue", 872 "scrub_min_txg", 873 "scrub_max_txg", 874 "scrub_func", 875 "scrub_errors", 876 NULL 877 }; 878 879 dsl_pool_t *dp = scn->scn_dp; 880 spa_t *spa = dp->dp_spa; 881 int i; 882 883 /* Remove any remnants of an old-style scrub. */ 884 for (i = 0; old_names[i]; i++) { 885 (void) zap_remove(dp->dp_meta_objset, 886 DMU_POOL_DIRECTORY_OBJECT, old_names[i], tx); 887 } 888 889 if (scn->scn_phys.scn_queue_obj != 0) { 890 VERIFY0(dmu_object_free(dp->dp_meta_objset, 891 scn->scn_phys.scn_queue_obj, tx)); 892 scn->scn_phys.scn_queue_obj = 0; 893 } 894 scan_ds_queue_clear(scn); 895 scan_ds_prefetch_queue_clear(scn); 896 897 scn->scn_phys.scn_flags &= ~DSF_SCRUB_PAUSED; 898 899 /* 900 * If we were "restarted" from a stopped state, don't bother 901 * with anything else. 902 */ 903 if (!dsl_scan_is_running(scn)) { 904 ASSERT(!scn->scn_is_sorted); 905 return; 906 } 907 908 if (scn->scn_is_sorted) { 909 scan_io_queues_destroy(scn); 910 scn->scn_is_sorted = B_FALSE; 911 912 if (scn->scn_taskq != NULL) { 913 taskq_destroy(scn->scn_taskq); 914 scn->scn_taskq = NULL; 915 } 916 } 917 918 scn->scn_phys.scn_state = complete ? DSS_FINISHED : DSS_CANCELED; 919 920 spa_notify_waiters(spa); 921 922 if (dsl_scan_restarting(scn, tx)) 923 spa_history_log_internal(spa, "scan aborted, restarting", tx, 924 "errors=%llu", (u_longlong_t)spa_get_errlog_size(spa)); 925 else if (!complete) 926 spa_history_log_internal(spa, "scan cancelled", tx, 927 "errors=%llu", (u_longlong_t)spa_get_errlog_size(spa)); 928 else 929 spa_history_log_internal(spa, "scan done", tx, 930 "errors=%llu", (u_longlong_t)spa_get_errlog_size(spa)); 931 932 if (DSL_SCAN_IS_SCRUB_RESILVER(scn)) { 933 spa->spa_scrub_active = B_FALSE; 934 935 /* 936 * If the scrub/resilver completed, update all DTLs to 937 * reflect this. Whether it succeeded or not, vacate 938 * all temporary scrub DTLs. 939 * 940 * As the scrub does not currently support traversing 941 * data that have been freed but are part of a checkpoint, 942 * we don't mark the scrub as done in the DTLs as faults 943 * may still exist in those vdevs. 944 */ 945 if (complete && 946 !spa_feature_is_active(spa, SPA_FEATURE_POOL_CHECKPOINT)) { 947 vdev_dtl_reassess(spa->spa_root_vdev, tx->tx_txg, 948 scn->scn_phys.scn_max_txg, B_TRUE, B_FALSE); 949 950 if (scn->scn_phys.scn_min_txg) { 951 nvlist_t *aux = fnvlist_alloc(); 952 fnvlist_add_string(aux, ZFS_EV_RESILVER_TYPE, 953 "healing"); 954 spa_event_notify(spa, NULL, aux, 955 ESC_ZFS_RESILVER_FINISH); 956 nvlist_free(aux); 957 } else { 958 spa_event_notify(spa, NULL, NULL, 959 ESC_ZFS_SCRUB_FINISH); 960 } 961 } else { 962 vdev_dtl_reassess(spa->spa_root_vdev, tx->tx_txg, 963 0, B_TRUE, B_FALSE); 964 } 965 spa_errlog_rotate(spa); 966 967 /* 968 * Don't clear flag until after vdev_dtl_reassess to ensure that 969 * DTL_MISSING will get updated when possible. 970 */ 971 spa->spa_scrub_started = B_FALSE; 972 973 /* 974 * We may have finished replacing a device. 975 * Let the async thread assess this and handle the detach. 976 */ 977 spa_async_request(spa, SPA_ASYNC_RESILVER_DONE); 978 979 /* 980 * Clear any resilver_deferred flags in the config. 981 * If there are drives that need resilvering, kick 982 * off an asynchronous request to start resilver. 983 * vdev_clear_resilver_deferred() may update the config 984 * before the resilver can restart. In the event of 985 * a crash during this period, the spa loading code 986 * will find the drives that need to be resilvered 987 * and start the resilver then. 988 */ 989 if (spa_feature_is_enabled(spa, SPA_FEATURE_RESILVER_DEFER) && 990 vdev_clear_resilver_deferred(spa->spa_root_vdev, tx)) { 991 spa_history_log_internal(spa, 992 "starting deferred resilver", tx, "errors=%llu", 993 (u_longlong_t)spa_get_errlog_size(spa)); 994 spa_async_request(spa, SPA_ASYNC_RESILVER); 995 } 996 997 /* Clear recent error events (i.e. duplicate events tracking) */ 998 if (complete) 999 zfs_ereport_clear(spa, NULL); 1000 } 1001 1002 scn->scn_phys.scn_end_time = gethrestime_sec(); 1003 1004 if (spa->spa_errata == ZPOOL_ERRATA_ZOL_2094_SCRUB) 1005 spa->spa_errata = 0; 1006 1007 ASSERT(!dsl_scan_is_running(scn)); 1008 } 1009 1010 static int 1011 dsl_scan_cancel_check(void *arg, dmu_tx_t *tx) 1012 { 1013 (void) arg; 1014 dsl_scan_t *scn = dmu_tx_pool(tx)->dp_scan; 1015 1016 if (!dsl_scan_is_running(scn)) 1017 return (SET_ERROR(ENOENT)); 1018 return (0); 1019 } 1020 1021 static void 1022 dsl_scan_cancel_sync(void *arg, dmu_tx_t *tx) 1023 { 1024 (void) arg; 1025 dsl_scan_t *scn = dmu_tx_pool(tx)->dp_scan; 1026 1027 dsl_scan_done(scn, B_FALSE, tx); 1028 dsl_scan_sync_state(scn, tx, SYNC_MANDATORY); 1029 spa_event_notify(scn->scn_dp->dp_spa, NULL, NULL, ESC_ZFS_SCRUB_ABORT); 1030 } 1031 1032 int 1033 dsl_scan_cancel(dsl_pool_t *dp) 1034 { 1035 return (dsl_sync_task(spa_name(dp->dp_spa), dsl_scan_cancel_check, 1036 dsl_scan_cancel_sync, NULL, 3, ZFS_SPACE_CHECK_RESERVED)); 1037 } 1038 1039 static int 1040 dsl_scrub_pause_resume_check(void *arg, dmu_tx_t *tx) 1041 { 1042 pool_scrub_cmd_t *cmd = arg; 1043 dsl_pool_t *dp = dmu_tx_pool(tx); 1044 dsl_scan_t *scn = dp->dp_scan; 1045 1046 if (*cmd == POOL_SCRUB_PAUSE) { 1047 /* can't pause a scrub when there is no in-progress scrub */ 1048 if (!dsl_scan_scrubbing(dp)) 1049 return (SET_ERROR(ENOENT)); 1050 1051 /* can't pause a paused scrub */ 1052 if (dsl_scan_is_paused_scrub(scn)) 1053 return (SET_ERROR(EBUSY)); 1054 } else if (*cmd != POOL_SCRUB_NORMAL) { 1055 return (SET_ERROR(ENOTSUP)); 1056 } 1057 1058 return (0); 1059 } 1060 1061 static void 1062 dsl_scrub_pause_resume_sync(void *arg, dmu_tx_t *tx) 1063 { 1064 pool_scrub_cmd_t *cmd = arg; 1065 dsl_pool_t *dp = dmu_tx_pool(tx); 1066 spa_t *spa = dp->dp_spa; 1067 dsl_scan_t *scn = dp->dp_scan; 1068 1069 if (*cmd == POOL_SCRUB_PAUSE) { 1070 /* can't pause a scrub when there is no in-progress scrub */ 1071 spa->spa_scan_pass_scrub_pause = gethrestime_sec(); 1072 scn->scn_phys.scn_flags |= DSF_SCRUB_PAUSED; 1073 scn->scn_phys_cached.scn_flags |= DSF_SCRUB_PAUSED; 1074 dsl_scan_sync_state(scn, tx, SYNC_CACHED); 1075 spa_event_notify(spa, NULL, NULL, ESC_ZFS_SCRUB_PAUSED); 1076 spa_notify_waiters(spa); 1077 } else { 1078 ASSERT3U(*cmd, ==, POOL_SCRUB_NORMAL); 1079 if (dsl_scan_is_paused_scrub(scn)) { 1080 /* 1081 * We need to keep track of how much time we spend 1082 * paused per pass so that we can adjust the scrub rate 1083 * shown in the output of 'zpool status' 1084 */ 1085 spa->spa_scan_pass_scrub_spent_paused += 1086 gethrestime_sec() - spa->spa_scan_pass_scrub_pause; 1087 spa->spa_scan_pass_scrub_pause = 0; 1088 scn->scn_phys.scn_flags &= ~DSF_SCRUB_PAUSED; 1089 scn->scn_phys_cached.scn_flags &= ~DSF_SCRUB_PAUSED; 1090 dsl_scan_sync_state(scn, tx, SYNC_CACHED); 1091 } 1092 } 1093 } 1094 1095 /* 1096 * Set scrub pause/resume state if it makes sense to do so 1097 */ 1098 int 1099 dsl_scrub_set_pause_resume(const dsl_pool_t *dp, pool_scrub_cmd_t cmd) 1100 { 1101 return (dsl_sync_task(spa_name(dp->dp_spa), 1102 dsl_scrub_pause_resume_check, dsl_scrub_pause_resume_sync, &cmd, 3, 1103 ZFS_SPACE_CHECK_RESERVED)); 1104 } 1105 1106 1107 /* start a new scan, or restart an existing one. */ 1108 void 1109 dsl_scan_restart_resilver(dsl_pool_t *dp, uint64_t txg) 1110 { 1111 if (txg == 0) { 1112 dmu_tx_t *tx; 1113 tx = dmu_tx_create_dd(dp->dp_mos_dir); 1114 VERIFY(0 == dmu_tx_assign(tx, TXG_WAIT)); 1115 1116 txg = dmu_tx_get_txg(tx); 1117 dp->dp_scan->scn_restart_txg = txg; 1118 dmu_tx_commit(tx); 1119 } else { 1120 dp->dp_scan->scn_restart_txg = txg; 1121 } 1122 zfs_dbgmsg("restarting resilver for %s at txg=%llu", 1123 dp->dp_spa->spa_name, (longlong_t)txg); 1124 } 1125 1126 void 1127 dsl_free(dsl_pool_t *dp, uint64_t txg, const blkptr_t *bp) 1128 { 1129 zio_free(dp->dp_spa, txg, bp); 1130 } 1131 1132 void 1133 dsl_free_sync(zio_t *pio, dsl_pool_t *dp, uint64_t txg, const blkptr_t *bpp) 1134 { 1135 ASSERT(dsl_pool_sync_context(dp)); 1136 zio_nowait(zio_free_sync(pio, dp->dp_spa, txg, bpp, pio->io_flags)); 1137 } 1138 1139 static int 1140 scan_ds_queue_compare(const void *a, const void *b) 1141 { 1142 const scan_ds_t *sds_a = a, *sds_b = b; 1143 1144 if (sds_a->sds_dsobj < sds_b->sds_dsobj) 1145 return (-1); 1146 if (sds_a->sds_dsobj == sds_b->sds_dsobj) 1147 return (0); 1148 return (1); 1149 } 1150 1151 static void 1152 scan_ds_queue_clear(dsl_scan_t *scn) 1153 { 1154 void *cookie = NULL; 1155 scan_ds_t *sds; 1156 while ((sds = avl_destroy_nodes(&scn->scn_queue, &cookie)) != NULL) { 1157 kmem_free(sds, sizeof (*sds)); 1158 } 1159 } 1160 1161 static boolean_t 1162 scan_ds_queue_contains(dsl_scan_t *scn, uint64_t dsobj, uint64_t *txg) 1163 { 1164 scan_ds_t srch, *sds; 1165 1166 srch.sds_dsobj = dsobj; 1167 sds = avl_find(&scn->scn_queue, &srch, NULL); 1168 if (sds != NULL && txg != NULL) 1169 *txg = sds->sds_txg; 1170 return (sds != NULL); 1171 } 1172 1173 static void 1174 scan_ds_queue_insert(dsl_scan_t *scn, uint64_t dsobj, uint64_t txg) 1175 { 1176 scan_ds_t *sds; 1177 avl_index_t where; 1178 1179 sds = kmem_zalloc(sizeof (*sds), KM_SLEEP); 1180 sds->sds_dsobj = dsobj; 1181 sds->sds_txg = txg; 1182 1183 VERIFY3P(avl_find(&scn->scn_queue, sds, &where), ==, NULL); 1184 avl_insert(&scn->scn_queue, sds, where); 1185 } 1186 1187 static void 1188 scan_ds_queue_remove(dsl_scan_t *scn, uint64_t dsobj) 1189 { 1190 scan_ds_t srch, *sds; 1191 1192 srch.sds_dsobj = dsobj; 1193 1194 sds = avl_find(&scn->scn_queue, &srch, NULL); 1195 VERIFY(sds != NULL); 1196 avl_remove(&scn->scn_queue, sds); 1197 kmem_free(sds, sizeof (*sds)); 1198 } 1199 1200 static void 1201 scan_ds_queue_sync(dsl_scan_t *scn, dmu_tx_t *tx) 1202 { 1203 dsl_pool_t *dp = scn->scn_dp; 1204 spa_t *spa = dp->dp_spa; 1205 dmu_object_type_t ot = (spa_version(spa) >= SPA_VERSION_DSL_SCRUB) ? 1206 DMU_OT_SCAN_QUEUE : DMU_OT_ZAP_OTHER; 1207 1208 ASSERT0(scn->scn_bytes_pending); 1209 ASSERT(scn->scn_phys.scn_queue_obj != 0); 1210 1211 VERIFY0(dmu_object_free(dp->dp_meta_objset, 1212 scn->scn_phys.scn_queue_obj, tx)); 1213 scn->scn_phys.scn_queue_obj = zap_create(dp->dp_meta_objset, ot, 1214 DMU_OT_NONE, 0, tx); 1215 for (scan_ds_t *sds = avl_first(&scn->scn_queue); 1216 sds != NULL; sds = AVL_NEXT(&scn->scn_queue, sds)) { 1217 VERIFY0(zap_add_int_key(dp->dp_meta_objset, 1218 scn->scn_phys.scn_queue_obj, sds->sds_dsobj, 1219 sds->sds_txg, tx)); 1220 } 1221 } 1222 1223 /* 1224 * Computes the memory limit state that we're currently in. A sorted scan 1225 * needs quite a bit of memory to hold the sorting queue, so we need to 1226 * reasonably constrain the size so it doesn't impact overall system 1227 * performance. We compute two limits: 1228 * 1) Hard memory limit: if the amount of memory used by the sorting 1229 * queues on a pool gets above this value, we stop the metadata 1230 * scanning portion and start issuing the queued up and sorted 1231 * I/Os to reduce memory usage. 1232 * This limit is calculated as a fraction of physmem (by default 5%). 1233 * We constrain the lower bound of the hard limit to an absolute 1234 * minimum of zfs_scan_mem_lim_min (default: 16 MiB). We also constrain 1235 * the upper bound to 5% of the total pool size - no chance we'll 1236 * ever need that much memory, but just to keep the value in check. 1237 * 2) Soft memory limit: once we hit the hard memory limit, we start 1238 * issuing I/O to reduce queue memory usage, but we don't want to 1239 * completely empty out the queues, since we might be able to find I/Os 1240 * that will fill in the gaps of our non-sequential IOs at some point 1241 * in the future. So we stop the issuing of I/Os once the amount of 1242 * memory used drops below the soft limit (at which point we stop issuing 1243 * I/O and start scanning metadata again). 1244 * 1245 * This limit is calculated by subtracting a fraction of the hard 1246 * limit from the hard limit. By default this fraction is 5%, so 1247 * the soft limit is 95% of the hard limit. We cap the size of the 1248 * difference between the hard and soft limits at an absolute 1249 * maximum of zfs_scan_mem_lim_soft_max (default: 128 MiB) - this is 1250 * sufficient to not cause too frequent switching between the 1251 * metadata scan and I/O issue (even at 2k recordsize, 128 MiB's 1252 * worth of queues is about 1.2 GiB of on-pool data, so scanning 1253 * that should take at least a decent fraction of a second). 1254 */ 1255 static boolean_t 1256 dsl_scan_should_clear(dsl_scan_t *scn) 1257 { 1258 spa_t *spa = scn->scn_dp->dp_spa; 1259 vdev_t *rvd = scn->scn_dp->dp_spa->spa_root_vdev; 1260 uint64_t alloc, mlim_hard, mlim_soft, mused; 1261 1262 alloc = metaslab_class_get_alloc(spa_normal_class(spa)); 1263 alloc += metaslab_class_get_alloc(spa_special_class(spa)); 1264 alloc += metaslab_class_get_alloc(spa_dedup_class(spa)); 1265 1266 mlim_hard = MAX((physmem / zfs_scan_mem_lim_fact) * PAGESIZE, 1267 zfs_scan_mem_lim_min); 1268 mlim_hard = MIN(mlim_hard, alloc / 20); 1269 mlim_soft = mlim_hard - MIN(mlim_hard / zfs_scan_mem_lim_soft_fact, 1270 zfs_scan_mem_lim_soft_max); 1271 mused = 0; 1272 for (uint64_t i = 0; i < rvd->vdev_children; i++) { 1273 vdev_t *tvd = rvd->vdev_child[i]; 1274 dsl_scan_io_queue_t *queue; 1275 1276 mutex_enter(&tvd->vdev_scan_io_queue_lock); 1277 queue = tvd->vdev_scan_io_queue; 1278 if (queue != NULL) { 1279 /* # extents in exts_by_size = # in exts_by_addr */ 1280 mused += zfs_btree_numnodes(&queue->q_exts_by_size) * 1281 sizeof (range_seg_gap_t) + queue->q_sio_memused; 1282 } 1283 mutex_exit(&tvd->vdev_scan_io_queue_lock); 1284 } 1285 1286 dprintf("current scan memory usage: %llu bytes\n", (longlong_t)mused); 1287 1288 if (mused == 0) 1289 ASSERT0(scn->scn_bytes_pending); 1290 1291 /* 1292 * If we are above our hard limit, we need to clear out memory. 1293 * If we are below our soft limit, we need to accumulate sequential IOs. 1294 * Otherwise, we should keep doing whatever we are currently doing. 1295 */ 1296 if (mused >= mlim_hard) 1297 return (B_TRUE); 1298 else if (mused < mlim_soft) 1299 return (B_FALSE); 1300 else 1301 return (scn->scn_clearing); 1302 } 1303 1304 static boolean_t 1305 dsl_scan_check_suspend(dsl_scan_t *scn, const zbookmark_phys_t *zb) 1306 { 1307 /* we never skip user/group accounting objects */ 1308 if (zb && (int64_t)zb->zb_object < 0) 1309 return (B_FALSE); 1310 1311 if (scn->scn_suspending) 1312 return (B_TRUE); /* we're already suspending */ 1313 1314 if (!ZB_IS_ZERO(&scn->scn_phys.scn_bookmark)) 1315 return (B_FALSE); /* we're resuming */ 1316 1317 /* We only know how to resume from level-0 and objset blocks. */ 1318 if (zb && (zb->zb_level != 0 && zb->zb_level != ZB_ROOT_LEVEL)) 1319 return (B_FALSE); 1320 1321 /* 1322 * We suspend if: 1323 * - we have scanned for at least the minimum time (default 1 sec 1324 * for scrub, 3 sec for resilver), and either we have sufficient 1325 * dirty data that we are starting to write more quickly 1326 * (default 30%), someone is explicitly waiting for this txg 1327 * to complete, or we have used up all of the time in the txg 1328 * timeout (default 5 sec). 1329 * or 1330 * - the spa is shutting down because this pool is being exported 1331 * or the machine is rebooting. 1332 * or 1333 * - the scan queue has reached its memory use limit 1334 */ 1335 uint64_t curr_time_ns = gethrtime(); 1336 uint64_t scan_time_ns = curr_time_ns - scn->scn_sync_start_time; 1337 uint64_t sync_time_ns = curr_time_ns - 1338 scn->scn_dp->dp_spa->spa_sync_starttime; 1339 int dirty_pct = scn->scn_dp->dp_dirty_total * 100 / zfs_dirty_data_max; 1340 int mintime = (scn->scn_phys.scn_func == POOL_SCAN_RESILVER) ? 1341 zfs_resilver_min_time_ms : zfs_scrub_min_time_ms; 1342 1343 if ((NSEC2MSEC(scan_time_ns) > mintime && 1344 (dirty_pct >= zfs_vdev_async_write_active_min_dirty_percent || 1345 txg_sync_waiting(scn->scn_dp) || 1346 NSEC2SEC(sync_time_ns) >= zfs_txg_timeout)) || 1347 spa_shutting_down(scn->scn_dp->dp_spa) || 1348 (zfs_scan_strict_mem_lim && dsl_scan_should_clear(scn))) { 1349 if (zb && zb->zb_level == ZB_ROOT_LEVEL) { 1350 dprintf("suspending at first available bookmark " 1351 "%llx/%llx/%llx/%llx\n", 1352 (longlong_t)zb->zb_objset, 1353 (longlong_t)zb->zb_object, 1354 (longlong_t)zb->zb_level, 1355 (longlong_t)zb->zb_blkid); 1356 SET_BOOKMARK(&scn->scn_phys.scn_bookmark, 1357 zb->zb_objset, 0, 0, 0); 1358 } else if (zb != NULL) { 1359 dprintf("suspending at bookmark %llx/%llx/%llx/%llx\n", 1360 (longlong_t)zb->zb_objset, 1361 (longlong_t)zb->zb_object, 1362 (longlong_t)zb->zb_level, 1363 (longlong_t)zb->zb_blkid); 1364 scn->scn_phys.scn_bookmark = *zb; 1365 } else { 1366 #ifdef ZFS_DEBUG 1367 dsl_scan_phys_t *scnp = &scn->scn_phys; 1368 dprintf("suspending at at DDT bookmark " 1369 "%llx/%llx/%llx/%llx\n", 1370 (longlong_t)scnp->scn_ddt_bookmark.ddb_class, 1371 (longlong_t)scnp->scn_ddt_bookmark.ddb_type, 1372 (longlong_t)scnp->scn_ddt_bookmark.ddb_checksum, 1373 (longlong_t)scnp->scn_ddt_bookmark.ddb_cursor); 1374 #endif 1375 } 1376 scn->scn_suspending = B_TRUE; 1377 return (B_TRUE); 1378 } 1379 return (B_FALSE); 1380 } 1381 1382 typedef struct zil_scan_arg { 1383 dsl_pool_t *zsa_dp; 1384 zil_header_t *zsa_zh; 1385 } zil_scan_arg_t; 1386 1387 static int 1388 dsl_scan_zil_block(zilog_t *zilog, const blkptr_t *bp, void *arg, 1389 uint64_t claim_txg) 1390 { 1391 (void) zilog; 1392 zil_scan_arg_t *zsa = arg; 1393 dsl_pool_t *dp = zsa->zsa_dp; 1394 dsl_scan_t *scn = dp->dp_scan; 1395 zil_header_t *zh = zsa->zsa_zh; 1396 zbookmark_phys_t zb; 1397 1398 ASSERT(!BP_IS_REDACTED(bp)); 1399 if (BP_IS_HOLE(bp) || bp->blk_birth <= scn->scn_phys.scn_cur_min_txg) 1400 return (0); 1401 1402 /* 1403 * One block ("stubby") can be allocated a long time ago; we 1404 * want to visit that one because it has been allocated 1405 * (on-disk) even if it hasn't been claimed (even though for 1406 * scrub there's nothing to do to it). 1407 */ 1408 if (claim_txg == 0 && bp->blk_birth >= spa_min_claim_txg(dp->dp_spa)) 1409 return (0); 1410 1411 SET_BOOKMARK(&zb, zh->zh_log.blk_cksum.zc_word[ZIL_ZC_OBJSET], 1412 ZB_ZIL_OBJECT, ZB_ZIL_LEVEL, bp->blk_cksum.zc_word[ZIL_ZC_SEQ]); 1413 1414 VERIFY(0 == scan_funcs[scn->scn_phys.scn_func](dp, bp, &zb)); 1415 return (0); 1416 } 1417 1418 static int 1419 dsl_scan_zil_record(zilog_t *zilog, const lr_t *lrc, void *arg, 1420 uint64_t claim_txg) 1421 { 1422 (void) zilog; 1423 if (lrc->lrc_txtype == TX_WRITE) { 1424 zil_scan_arg_t *zsa = arg; 1425 dsl_pool_t *dp = zsa->zsa_dp; 1426 dsl_scan_t *scn = dp->dp_scan; 1427 zil_header_t *zh = zsa->zsa_zh; 1428 const lr_write_t *lr = (const lr_write_t *)lrc; 1429 const blkptr_t *bp = &lr->lr_blkptr; 1430 zbookmark_phys_t zb; 1431 1432 ASSERT(!BP_IS_REDACTED(bp)); 1433 if (BP_IS_HOLE(bp) || 1434 bp->blk_birth <= scn->scn_phys.scn_cur_min_txg) 1435 return (0); 1436 1437 /* 1438 * birth can be < claim_txg if this record's txg is 1439 * already txg sync'ed (but this log block contains 1440 * other records that are not synced) 1441 */ 1442 if (claim_txg == 0 || bp->blk_birth < claim_txg) 1443 return (0); 1444 1445 SET_BOOKMARK(&zb, zh->zh_log.blk_cksum.zc_word[ZIL_ZC_OBJSET], 1446 lr->lr_foid, ZB_ZIL_LEVEL, 1447 lr->lr_offset / BP_GET_LSIZE(bp)); 1448 1449 VERIFY(0 == scan_funcs[scn->scn_phys.scn_func](dp, bp, &zb)); 1450 } 1451 return (0); 1452 } 1453 1454 static void 1455 dsl_scan_zil(dsl_pool_t *dp, zil_header_t *zh) 1456 { 1457 uint64_t claim_txg = zh->zh_claim_txg; 1458 zil_scan_arg_t zsa = { dp, zh }; 1459 zilog_t *zilog; 1460 1461 ASSERT(spa_writeable(dp->dp_spa)); 1462 1463 /* 1464 * We only want to visit blocks that have been claimed but not yet 1465 * replayed (or, in read-only mode, blocks that *would* be claimed). 1466 */ 1467 if (claim_txg == 0) 1468 return; 1469 1470 zilog = zil_alloc(dp->dp_meta_objset, zh); 1471 1472 (void) zil_parse(zilog, dsl_scan_zil_block, dsl_scan_zil_record, &zsa, 1473 claim_txg, B_FALSE); 1474 1475 zil_free(zilog); 1476 } 1477 1478 /* 1479 * We compare scan_prefetch_issue_ctx_t's based on their bookmarks. The idea 1480 * here is to sort the AVL tree by the order each block will be needed. 1481 */ 1482 static int 1483 scan_prefetch_queue_compare(const void *a, const void *b) 1484 { 1485 const scan_prefetch_issue_ctx_t *spic_a = a, *spic_b = b; 1486 const scan_prefetch_ctx_t *spc_a = spic_a->spic_spc; 1487 const scan_prefetch_ctx_t *spc_b = spic_b->spic_spc; 1488 1489 return (zbookmark_compare(spc_a->spc_datablkszsec, 1490 spc_a->spc_indblkshift, spc_b->spc_datablkszsec, 1491 spc_b->spc_indblkshift, &spic_a->spic_zb, &spic_b->spic_zb)); 1492 } 1493 1494 static void 1495 scan_prefetch_ctx_rele(scan_prefetch_ctx_t *spc, void *tag) 1496 { 1497 if (zfs_refcount_remove(&spc->spc_refcnt, tag) == 0) { 1498 zfs_refcount_destroy(&spc->spc_refcnt); 1499 kmem_free(spc, sizeof (scan_prefetch_ctx_t)); 1500 } 1501 } 1502 1503 static scan_prefetch_ctx_t * 1504 scan_prefetch_ctx_create(dsl_scan_t *scn, dnode_phys_t *dnp, void *tag) 1505 { 1506 scan_prefetch_ctx_t *spc; 1507 1508 spc = kmem_alloc(sizeof (scan_prefetch_ctx_t), KM_SLEEP); 1509 zfs_refcount_create(&spc->spc_refcnt); 1510 zfs_refcount_add(&spc->spc_refcnt, tag); 1511 spc->spc_scn = scn; 1512 if (dnp != NULL) { 1513 spc->spc_datablkszsec = dnp->dn_datablkszsec; 1514 spc->spc_indblkshift = dnp->dn_indblkshift; 1515 spc->spc_root = B_FALSE; 1516 } else { 1517 spc->spc_datablkszsec = 0; 1518 spc->spc_indblkshift = 0; 1519 spc->spc_root = B_TRUE; 1520 } 1521 1522 return (spc); 1523 } 1524 1525 static void 1526 scan_prefetch_ctx_add_ref(scan_prefetch_ctx_t *spc, void *tag) 1527 { 1528 zfs_refcount_add(&spc->spc_refcnt, tag); 1529 } 1530 1531 static void 1532 scan_ds_prefetch_queue_clear(dsl_scan_t *scn) 1533 { 1534 spa_t *spa = scn->scn_dp->dp_spa; 1535 void *cookie = NULL; 1536 scan_prefetch_issue_ctx_t *spic = NULL; 1537 1538 mutex_enter(&spa->spa_scrub_lock); 1539 while ((spic = avl_destroy_nodes(&scn->scn_prefetch_queue, 1540 &cookie)) != NULL) { 1541 scan_prefetch_ctx_rele(spic->spic_spc, scn); 1542 kmem_free(spic, sizeof (scan_prefetch_issue_ctx_t)); 1543 } 1544 mutex_exit(&spa->spa_scrub_lock); 1545 } 1546 1547 static boolean_t 1548 dsl_scan_check_prefetch_resume(scan_prefetch_ctx_t *spc, 1549 const zbookmark_phys_t *zb) 1550 { 1551 zbookmark_phys_t *last_zb = &spc->spc_scn->scn_prefetch_bookmark; 1552 dnode_phys_t tmp_dnp; 1553 dnode_phys_t *dnp = (spc->spc_root) ? NULL : &tmp_dnp; 1554 1555 if (zb->zb_objset != last_zb->zb_objset) 1556 return (B_TRUE); 1557 if ((int64_t)zb->zb_object < 0) 1558 return (B_FALSE); 1559 1560 tmp_dnp.dn_datablkszsec = spc->spc_datablkszsec; 1561 tmp_dnp.dn_indblkshift = spc->spc_indblkshift; 1562 1563 if (zbookmark_subtree_completed(dnp, zb, last_zb)) 1564 return (B_TRUE); 1565 1566 return (B_FALSE); 1567 } 1568 1569 static void 1570 dsl_scan_prefetch(scan_prefetch_ctx_t *spc, blkptr_t *bp, zbookmark_phys_t *zb) 1571 { 1572 avl_index_t idx; 1573 dsl_scan_t *scn = spc->spc_scn; 1574 spa_t *spa = scn->scn_dp->dp_spa; 1575 scan_prefetch_issue_ctx_t *spic; 1576 1577 if (zfs_no_scrub_prefetch || BP_IS_REDACTED(bp)) 1578 return; 1579 1580 if (BP_IS_HOLE(bp) || bp->blk_birth <= scn->scn_phys.scn_cur_min_txg || 1581 (BP_GET_LEVEL(bp) == 0 && BP_GET_TYPE(bp) != DMU_OT_DNODE && 1582 BP_GET_TYPE(bp) != DMU_OT_OBJSET)) 1583 return; 1584 1585 if (dsl_scan_check_prefetch_resume(spc, zb)) 1586 return; 1587 1588 scan_prefetch_ctx_add_ref(spc, scn); 1589 spic = kmem_alloc(sizeof (scan_prefetch_issue_ctx_t), KM_SLEEP); 1590 spic->spic_spc = spc; 1591 spic->spic_bp = *bp; 1592 spic->spic_zb = *zb; 1593 1594 /* 1595 * Add the IO to the queue of blocks to prefetch. This allows us to 1596 * prioritize blocks that we will need first for the main traversal 1597 * thread. 1598 */ 1599 mutex_enter(&spa->spa_scrub_lock); 1600 if (avl_find(&scn->scn_prefetch_queue, spic, &idx) != NULL) { 1601 /* this block is already queued for prefetch */ 1602 kmem_free(spic, sizeof (scan_prefetch_issue_ctx_t)); 1603 scan_prefetch_ctx_rele(spc, scn); 1604 mutex_exit(&spa->spa_scrub_lock); 1605 return; 1606 } 1607 1608 avl_insert(&scn->scn_prefetch_queue, spic, idx); 1609 cv_broadcast(&spa->spa_scrub_io_cv); 1610 mutex_exit(&spa->spa_scrub_lock); 1611 } 1612 1613 static void 1614 dsl_scan_prefetch_dnode(dsl_scan_t *scn, dnode_phys_t *dnp, 1615 uint64_t objset, uint64_t object) 1616 { 1617 int i; 1618 zbookmark_phys_t zb; 1619 scan_prefetch_ctx_t *spc; 1620 1621 if (dnp->dn_nblkptr == 0 && !(dnp->dn_flags & DNODE_FLAG_SPILL_BLKPTR)) 1622 return; 1623 1624 SET_BOOKMARK(&zb, objset, object, 0, 0); 1625 1626 spc = scan_prefetch_ctx_create(scn, dnp, FTAG); 1627 1628 for (i = 0; i < dnp->dn_nblkptr; i++) { 1629 zb.zb_level = BP_GET_LEVEL(&dnp->dn_blkptr[i]); 1630 zb.zb_blkid = i; 1631 dsl_scan_prefetch(spc, &dnp->dn_blkptr[i], &zb); 1632 } 1633 1634 if (dnp->dn_flags & DNODE_FLAG_SPILL_BLKPTR) { 1635 zb.zb_level = 0; 1636 zb.zb_blkid = DMU_SPILL_BLKID; 1637 dsl_scan_prefetch(spc, DN_SPILL_BLKPTR(dnp), &zb); 1638 } 1639 1640 scan_prefetch_ctx_rele(spc, FTAG); 1641 } 1642 1643 static void 1644 dsl_scan_prefetch_cb(zio_t *zio, const zbookmark_phys_t *zb, const blkptr_t *bp, 1645 arc_buf_t *buf, void *private) 1646 { 1647 (void) zio; 1648 scan_prefetch_ctx_t *spc = private; 1649 dsl_scan_t *scn = spc->spc_scn; 1650 spa_t *spa = scn->scn_dp->dp_spa; 1651 1652 /* broadcast that the IO has completed for rate limiting purposes */ 1653 mutex_enter(&spa->spa_scrub_lock); 1654 ASSERT3U(spa->spa_scrub_inflight, >=, BP_GET_PSIZE(bp)); 1655 spa->spa_scrub_inflight -= BP_GET_PSIZE(bp); 1656 cv_broadcast(&spa->spa_scrub_io_cv); 1657 mutex_exit(&spa->spa_scrub_lock); 1658 1659 /* if there was an error or we are done prefetching, just cleanup */ 1660 if (buf == NULL || scn->scn_prefetch_stop) 1661 goto out; 1662 1663 if (BP_GET_LEVEL(bp) > 0) { 1664 int i; 1665 blkptr_t *cbp; 1666 int epb = BP_GET_LSIZE(bp) >> SPA_BLKPTRSHIFT; 1667 zbookmark_phys_t czb; 1668 1669 for (i = 0, cbp = buf->b_data; i < epb; i++, cbp++) { 1670 SET_BOOKMARK(&czb, zb->zb_objset, zb->zb_object, 1671 zb->zb_level - 1, zb->zb_blkid * epb + i); 1672 dsl_scan_prefetch(spc, cbp, &czb); 1673 } 1674 } else if (BP_GET_TYPE(bp) == DMU_OT_DNODE) { 1675 dnode_phys_t *cdnp; 1676 int i; 1677 int epb = BP_GET_LSIZE(bp) >> DNODE_SHIFT; 1678 1679 for (i = 0, cdnp = buf->b_data; i < epb; 1680 i += cdnp->dn_extra_slots + 1, 1681 cdnp += cdnp->dn_extra_slots + 1) { 1682 dsl_scan_prefetch_dnode(scn, cdnp, 1683 zb->zb_objset, zb->zb_blkid * epb + i); 1684 } 1685 } else if (BP_GET_TYPE(bp) == DMU_OT_OBJSET) { 1686 objset_phys_t *osp = buf->b_data; 1687 1688 dsl_scan_prefetch_dnode(scn, &osp->os_meta_dnode, 1689 zb->zb_objset, DMU_META_DNODE_OBJECT); 1690 1691 if (OBJSET_BUF_HAS_USERUSED(buf)) { 1692 dsl_scan_prefetch_dnode(scn, 1693 &osp->os_groupused_dnode, zb->zb_objset, 1694 DMU_GROUPUSED_OBJECT); 1695 dsl_scan_prefetch_dnode(scn, 1696 &osp->os_userused_dnode, zb->zb_objset, 1697 DMU_USERUSED_OBJECT); 1698 } 1699 } 1700 1701 out: 1702 if (buf != NULL) 1703 arc_buf_destroy(buf, private); 1704 scan_prefetch_ctx_rele(spc, scn); 1705 } 1706 1707 static void 1708 dsl_scan_prefetch_thread(void *arg) 1709 { 1710 dsl_scan_t *scn = arg; 1711 spa_t *spa = scn->scn_dp->dp_spa; 1712 scan_prefetch_issue_ctx_t *spic; 1713 1714 /* loop until we are told to stop */ 1715 while (!scn->scn_prefetch_stop) { 1716 arc_flags_t flags = ARC_FLAG_NOWAIT | 1717 ARC_FLAG_PRESCIENT_PREFETCH | ARC_FLAG_PREFETCH; 1718 int zio_flags = ZIO_FLAG_CANFAIL | ZIO_FLAG_SCAN_THREAD; 1719 1720 mutex_enter(&spa->spa_scrub_lock); 1721 1722 /* 1723 * Wait until we have an IO to issue and are not above our 1724 * maximum in flight limit. 1725 */ 1726 while (!scn->scn_prefetch_stop && 1727 (avl_numnodes(&scn->scn_prefetch_queue) == 0 || 1728 spa->spa_scrub_inflight >= scn->scn_maxinflight_bytes)) { 1729 cv_wait(&spa->spa_scrub_io_cv, &spa->spa_scrub_lock); 1730 } 1731 1732 /* recheck if we should stop since we waited for the cv */ 1733 if (scn->scn_prefetch_stop) { 1734 mutex_exit(&spa->spa_scrub_lock); 1735 break; 1736 } 1737 1738 /* remove the prefetch IO from the tree */ 1739 spic = avl_first(&scn->scn_prefetch_queue); 1740 spa->spa_scrub_inflight += BP_GET_PSIZE(&spic->spic_bp); 1741 avl_remove(&scn->scn_prefetch_queue, spic); 1742 1743 mutex_exit(&spa->spa_scrub_lock); 1744 1745 if (BP_IS_PROTECTED(&spic->spic_bp)) { 1746 ASSERT(BP_GET_TYPE(&spic->spic_bp) == DMU_OT_DNODE || 1747 BP_GET_TYPE(&spic->spic_bp) == DMU_OT_OBJSET); 1748 ASSERT3U(BP_GET_LEVEL(&spic->spic_bp), ==, 0); 1749 zio_flags |= ZIO_FLAG_RAW; 1750 } 1751 1752 /* issue the prefetch asynchronously */ 1753 (void) arc_read(scn->scn_zio_root, scn->scn_dp->dp_spa, 1754 &spic->spic_bp, dsl_scan_prefetch_cb, spic->spic_spc, 1755 ZIO_PRIORITY_SCRUB, zio_flags, &flags, &spic->spic_zb); 1756 1757 kmem_free(spic, sizeof (scan_prefetch_issue_ctx_t)); 1758 } 1759 1760 ASSERT(scn->scn_prefetch_stop); 1761 1762 /* free any prefetches we didn't get to complete */ 1763 mutex_enter(&spa->spa_scrub_lock); 1764 while ((spic = avl_first(&scn->scn_prefetch_queue)) != NULL) { 1765 avl_remove(&scn->scn_prefetch_queue, spic); 1766 scan_prefetch_ctx_rele(spic->spic_spc, scn); 1767 kmem_free(spic, sizeof (scan_prefetch_issue_ctx_t)); 1768 } 1769 ASSERT0(avl_numnodes(&scn->scn_prefetch_queue)); 1770 mutex_exit(&spa->spa_scrub_lock); 1771 } 1772 1773 static boolean_t 1774 dsl_scan_check_resume(dsl_scan_t *scn, const dnode_phys_t *dnp, 1775 const zbookmark_phys_t *zb) 1776 { 1777 /* 1778 * We never skip over user/group accounting objects (obj<0) 1779 */ 1780 if (!ZB_IS_ZERO(&scn->scn_phys.scn_bookmark) && 1781 (int64_t)zb->zb_object >= 0) { 1782 /* 1783 * If we already visited this bp & everything below (in 1784 * a prior txg sync), don't bother doing it again. 1785 */ 1786 if (zbookmark_subtree_completed(dnp, zb, 1787 &scn->scn_phys.scn_bookmark)) 1788 return (B_TRUE); 1789 1790 /* 1791 * If we found the block we're trying to resume from, or 1792 * we went past it to a different object, zero it out to 1793 * indicate that it's OK to start checking for suspending 1794 * again. 1795 */ 1796 if (memcmp(zb, &scn->scn_phys.scn_bookmark, 1797 sizeof (*zb)) == 0 || 1798 zb->zb_object > scn->scn_phys.scn_bookmark.zb_object) { 1799 dprintf("resuming at %llx/%llx/%llx/%llx\n", 1800 (longlong_t)zb->zb_objset, 1801 (longlong_t)zb->zb_object, 1802 (longlong_t)zb->zb_level, 1803 (longlong_t)zb->zb_blkid); 1804 memset(&scn->scn_phys.scn_bookmark, 0, sizeof (*zb)); 1805 } 1806 } 1807 return (B_FALSE); 1808 } 1809 1810 static void dsl_scan_visitbp(blkptr_t *bp, const zbookmark_phys_t *zb, 1811 dnode_phys_t *dnp, dsl_dataset_t *ds, dsl_scan_t *scn, 1812 dmu_objset_type_t ostype, dmu_tx_t *tx); 1813 inline __attribute__((always_inline)) static void dsl_scan_visitdnode( 1814 dsl_scan_t *, dsl_dataset_t *ds, dmu_objset_type_t ostype, 1815 dnode_phys_t *dnp, uint64_t object, dmu_tx_t *tx); 1816 1817 /* 1818 * Return nonzero on i/o error. 1819 * Return new buf to write out in *bufp. 1820 */ 1821 inline __attribute__((always_inline)) static int 1822 dsl_scan_recurse(dsl_scan_t *scn, dsl_dataset_t *ds, dmu_objset_type_t ostype, 1823 dnode_phys_t *dnp, const blkptr_t *bp, 1824 const zbookmark_phys_t *zb, dmu_tx_t *tx) 1825 { 1826 dsl_pool_t *dp = scn->scn_dp; 1827 spa_t *spa = dp->dp_spa; 1828 int zio_flags = ZIO_FLAG_CANFAIL | ZIO_FLAG_SCAN_THREAD; 1829 int err; 1830 1831 ASSERT(!BP_IS_REDACTED(bp)); 1832 1833 /* 1834 * There is an unlikely case of encountering dnodes with contradicting 1835 * dn_bonuslen and DNODE_FLAG_SPILL_BLKPTR flag before in files created 1836 * or modified before commit 4254acb was merged. As it is not possible 1837 * to know which of the two is correct, report an error. 1838 */ 1839 if (dnp != NULL && 1840 dnp->dn_bonuslen > DN_MAX_BONUS_LEN(dnp)) { 1841 scn->scn_phys.scn_errors++; 1842 spa_log_error(spa, zb); 1843 return (SET_ERROR(EINVAL)); 1844 } 1845 1846 if (BP_GET_LEVEL(bp) > 0) { 1847 arc_flags_t flags = ARC_FLAG_WAIT; 1848 int i; 1849 blkptr_t *cbp; 1850 int epb = BP_GET_LSIZE(bp) >> SPA_BLKPTRSHIFT; 1851 arc_buf_t *buf; 1852 1853 err = arc_read(NULL, spa, bp, arc_getbuf_func, &buf, 1854 ZIO_PRIORITY_SCRUB, zio_flags, &flags, zb); 1855 if (err) { 1856 scn->scn_phys.scn_errors++; 1857 return (err); 1858 } 1859 for (i = 0, cbp = buf->b_data; i < epb; i++, cbp++) { 1860 zbookmark_phys_t czb; 1861 1862 SET_BOOKMARK(&czb, zb->zb_objset, zb->zb_object, 1863 zb->zb_level - 1, 1864 zb->zb_blkid * epb + i); 1865 dsl_scan_visitbp(cbp, &czb, dnp, 1866 ds, scn, ostype, tx); 1867 } 1868 arc_buf_destroy(buf, &buf); 1869 } else if (BP_GET_TYPE(bp) == DMU_OT_DNODE) { 1870 arc_flags_t flags = ARC_FLAG_WAIT; 1871 dnode_phys_t *cdnp; 1872 int i; 1873 int epb = BP_GET_LSIZE(bp) >> DNODE_SHIFT; 1874 arc_buf_t *buf; 1875 1876 if (BP_IS_PROTECTED(bp)) { 1877 ASSERT3U(BP_GET_COMPRESS(bp), ==, ZIO_COMPRESS_OFF); 1878 zio_flags |= ZIO_FLAG_RAW; 1879 } 1880 1881 err = arc_read(NULL, spa, bp, arc_getbuf_func, &buf, 1882 ZIO_PRIORITY_SCRUB, zio_flags, &flags, zb); 1883 if (err) { 1884 scn->scn_phys.scn_errors++; 1885 return (err); 1886 } 1887 for (i = 0, cdnp = buf->b_data; i < epb; 1888 i += cdnp->dn_extra_slots + 1, 1889 cdnp += cdnp->dn_extra_slots + 1) { 1890 dsl_scan_visitdnode(scn, ds, ostype, 1891 cdnp, zb->zb_blkid * epb + i, tx); 1892 } 1893 1894 arc_buf_destroy(buf, &buf); 1895 } else if (BP_GET_TYPE(bp) == DMU_OT_OBJSET) { 1896 arc_flags_t flags = ARC_FLAG_WAIT; 1897 objset_phys_t *osp; 1898 arc_buf_t *buf; 1899 1900 err = arc_read(NULL, spa, bp, arc_getbuf_func, &buf, 1901 ZIO_PRIORITY_SCRUB, zio_flags, &flags, zb); 1902 if (err) { 1903 scn->scn_phys.scn_errors++; 1904 return (err); 1905 } 1906 1907 osp = buf->b_data; 1908 1909 dsl_scan_visitdnode(scn, ds, osp->os_type, 1910 &osp->os_meta_dnode, DMU_META_DNODE_OBJECT, tx); 1911 1912 if (OBJSET_BUF_HAS_USERUSED(buf)) { 1913 /* 1914 * We also always visit user/group/project accounting 1915 * objects, and never skip them, even if we are 1916 * suspending. This is necessary so that the 1917 * space deltas from this txg get integrated. 1918 */ 1919 if (OBJSET_BUF_HAS_PROJECTUSED(buf)) 1920 dsl_scan_visitdnode(scn, ds, osp->os_type, 1921 &osp->os_projectused_dnode, 1922 DMU_PROJECTUSED_OBJECT, tx); 1923 dsl_scan_visitdnode(scn, ds, osp->os_type, 1924 &osp->os_groupused_dnode, 1925 DMU_GROUPUSED_OBJECT, tx); 1926 dsl_scan_visitdnode(scn, ds, osp->os_type, 1927 &osp->os_userused_dnode, 1928 DMU_USERUSED_OBJECT, tx); 1929 } 1930 arc_buf_destroy(buf, &buf); 1931 } else if (!zfs_blkptr_verify(spa, bp, B_FALSE, BLK_VERIFY_LOG)) { 1932 /* 1933 * Sanity check the block pointer contents, this is handled 1934 * by arc_read() for the cases above. 1935 */ 1936 scn->scn_phys.scn_errors++; 1937 spa_log_error(spa, zb); 1938 return (SET_ERROR(EINVAL)); 1939 } 1940 1941 return (0); 1942 } 1943 1944 inline __attribute__((always_inline)) static void 1945 dsl_scan_visitdnode(dsl_scan_t *scn, dsl_dataset_t *ds, 1946 dmu_objset_type_t ostype, dnode_phys_t *dnp, 1947 uint64_t object, dmu_tx_t *tx) 1948 { 1949 int j; 1950 1951 for (j = 0; j < dnp->dn_nblkptr; j++) { 1952 zbookmark_phys_t czb; 1953 1954 SET_BOOKMARK(&czb, ds ? ds->ds_object : 0, object, 1955 dnp->dn_nlevels - 1, j); 1956 dsl_scan_visitbp(&dnp->dn_blkptr[j], 1957 &czb, dnp, ds, scn, ostype, tx); 1958 } 1959 1960 if (dnp->dn_flags & DNODE_FLAG_SPILL_BLKPTR) { 1961 zbookmark_phys_t czb; 1962 SET_BOOKMARK(&czb, ds ? ds->ds_object : 0, object, 1963 0, DMU_SPILL_BLKID); 1964 dsl_scan_visitbp(DN_SPILL_BLKPTR(dnp), 1965 &czb, dnp, ds, scn, ostype, tx); 1966 } 1967 } 1968 1969 /* 1970 * The arguments are in this order because mdb can only print the 1971 * first 5; we want them to be useful. 1972 */ 1973 static void 1974 dsl_scan_visitbp(blkptr_t *bp, const zbookmark_phys_t *zb, 1975 dnode_phys_t *dnp, dsl_dataset_t *ds, dsl_scan_t *scn, 1976 dmu_objset_type_t ostype, dmu_tx_t *tx) 1977 { 1978 dsl_pool_t *dp = scn->scn_dp; 1979 blkptr_t *bp_toread = NULL; 1980 1981 if (dsl_scan_check_suspend(scn, zb)) 1982 return; 1983 1984 if (dsl_scan_check_resume(scn, dnp, zb)) 1985 return; 1986 1987 scn->scn_visited_this_txg++; 1988 1989 if (BP_IS_HOLE(bp)) { 1990 scn->scn_holes_this_txg++; 1991 return; 1992 } 1993 1994 if (BP_IS_REDACTED(bp)) { 1995 ASSERT(dsl_dataset_feature_is_active(ds, 1996 SPA_FEATURE_REDACTED_DATASETS)); 1997 return; 1998 } 1999 2000 if (bp->blk_birth <= scn->scn_phys.scn_cur_min_txg) { 2001 scn->scn_lt_min_this_txg++; 2002 return; 2003 } 2004 2005 bp_toread = kmem_alloc(sizeof (blkptr_t), KM_SLEEP); 2006 *bp_toread = *bp; 2007 2008 if (dsl_scan_recurse(scn, ds, ostype, dnp, bp_toread, zb, tx) != 0) 2009 goto out; 2010 2011 /* 2012 * If dsl_scan_ddt() has already visited this block, it will have 2013 * already done any translations or scrubbing, so don't call the 2014 * callback again. 2015 */ 2016 if (ddt_class_contains(dp->dp_spa, 2017 scn->scn_phys.scn_ddt_class_max, bp)) { 2018 scn->scn_ddt_contained_this_txg++; 2019 goto out; 2020 } 2021 2022 /* 2023 * If this block is from the future (after cur_max_txg), then we 2024 * are doing this on behalf of a deleted snapshot, and we will 2025 * revisit the future block on the next pass of this dataset. 2026 * Don't scan it now unless we need to because something 2027 * under it was modified. 2028 */ 2029 if (BP_PHYSICAL_BIRTH(bp) > scn->scn_phys.scn_cur_max_txg) { 2030 scn->scn_gt_max_this_txg++; 2031 goto out; 2032 } 2033 2034 scan_funcs[scn->scn_phys.scn_func](dp, bp, zb); 2035 2036 out: 2037 kmem_free(bp_toread, sizeof (blkptr_t)); 2038 } 2039 2040 static void 2041 dsl_scan_visit_rootbp(dsl_scan_t *scn, dsl_dataset_t *ds, blkptr_t *bp, 2042 dmu_tx_t *tx) 2043 { 2044 zbookmark_phys_t zb; 2045 scan_prefetch_ctx_t *spc; 2046 2047 SET_BOOKMARK(&zb, ds ? ds->ds_object : DMU_META_OBJSET, 2048 ZB_ROOT_OBJECT, ZB_ROOT_LEVEL, ZB_ROOT_BLKID); 2049 2050 if (ZB_IS_ZERO(&scn->scn_phys.scn_bookmark)) { 2051 SET_BOOKMARK(&scn->scn_prefetch_bookmark, 2052 zb.zb_objset, 0, 0, 0); 2053 } else { 2054 scn->scn_prefetch_bookmark = scn->scn_phys.scn_bookmark; 2055 } 2056 2057 scn->scn_objsets_visited_this_txg++; 2058 2059 spc = scan_prefetch_ctx_create(scn, NULL, FTAG); 2060 dsl_scan_prefetch(spc, bp, &zb); 2061 scan_prefetch_ctx_rele(spc, FTAG); 2062 2063 dsl_scan_visitbp(bp, &zb, NULL, ds, scn, DMU_OST_NONE, tx); 2064 2065 dprintf_ds(ds, "finished scan%s", ""); 2066 } 2067 2068 static void 2069 ds_destroyed_scn_phys(dsl_dataset_t *ds, dsl_scan_phys_t *scn_phys) 2070 { 2071 if (scn_phys->scn_bookmark.zb_objset == ds->ds_object) { 2072 if (ds->ds_is_snapshot) { 2073 /* 2074 * Note: 2075 * - scn_cur_{min,max}_txg stays the same. 2076 * - Setting the flag is not really necessary if 2077 * scn_cur_max_txg == scn_max_txg, because there 2078 * is nothing after this snapshot that we care 2079 * about. However, we set it anyway and then 2080 * ignore it when we retraverse it in 2081 * dsl_scan_visitds(). 2082 */ 2083 scn_phys->scn_bookmark.zb_objset = 2084 dsl_dataset_phys(ds)->ds_next_snap_obj; 2085 zfs_dbgmsg("destroying ds %llu on %s; currently " 2086 "traversing; reset zb_objset to %llu", 2087 (u_longlong_t)ds->ds_object, 2088 ds->ds_dir->dd_pool->dp_spa->spa_name, 2089 (u_longlong_t)dsl_dataset_phys(ds)-> 2090 ds_next_snap_obj); 2091 scn_phys->scn_flags |= DSF_VISIT_DS_AGAIN; 2092 } else { 2093 SET_BOOKMARK(&scn_phys->scn_bookmark, 2094 ZB_DESTROYED_OBJSET, 0, 0, 0); 2095 zfs_dbgmsg("destroying ds %llu on %s; currently " 2096 "traversing; reset bookmark to -1,0,0,0", 2097 (u_longlong_t)ds->ds_object, 2098 ds->ds_dir->dd_pool->dp_spa->spa_name); 2099 } 2100 } 2101 } 2102 2103 /* 2104 * Invoked when a dataset is destroyed. We need to make sure that: 2105 * 2106 * 1) If it is the dataset that was currently being scanned, we write 2107 * a new dsl_scan_phys_t and marking the objset reference in it 2108 * as destroyed. 2109 * 2) Remove it from the work queue, if it was present. 2110 * 2111 * If the dataset was actually a snapshot, instead of marking the dataset 2112 * as destroyed, we instead substitute the next snapshot in line. 2113 */ 2114 void 2115 dsl_scan_ds_destroyed(dsl_dataset_t *ds, dmu_tx_t *tx) 2116 { 2117 dsl_pool_t *dp = ds->ds_dir->dd_pool; 2118 dsl_scan_t *scn = dp->dp_scan; 2119 uint64_t mintxg; 2120 2121 if (!dsl_scan_is_running(scn)) 2122 return; 2123 2124 ds_destroyed_scn_phys(ds, &scn->scn_phys); 2125 ds_destroyed_scn_phys(ds, &scn->scn_phys_cached); 2126 2127 if (scan_ds_queue_contains(scn, ds->ds_object, &mintxg)) { 2128 scan_ds_queue_remove(scn, ds->ds_object); 2129 if (ds->ds_is_snapshot) 2130 scan_ds_queue_insert(scn, 2131 dsl_dataset_phys(ds)->ds_next_snap_obj, mintxg); 2132 } 2133 2134 if (zap_lookup_int_key(dp->dp_meta_objset, scn->scn_phys.scn_queue_obj, 2135 ds->ds_object, &mintxg) == 0) { 2136 ASSERT3U(dsl_dataset_phys(ds)->ds_num_children, <=, 1); 2137 VERIFY3U(0, ==, zap_remove_int(dp->dp_meta_objset, 2138 scn->scn_phys.scn_queue_obj, ds->ds_object, tx)); 2139 if (ds->ds_is_snapshot) { 2140 /* 2141 * We keep the same mintxg; it could be > 2142 * ds_creation_txg if the previous snapshot was 2143 * deleted too. 2144 */ 2145 VERIFY(zap_add_int_key(dp->dp_meta_objset, 2146 scn->scn_phys.scn_queue_obj, 2147 dsl_dataset_phys(ds)->ds_next_snap_obj, 2148 mintxg, tx) == 0); 2149 zfs_dbgmsg("destroying ds %llu on %s; in queue; " 2150 "replacing with %llu", 2151 (u_longlong_t)ds->ds_object, 2152 dp->dp_spa->spa_name, 2153 (u_longlong_t)dsl_dataset_phys(ds)-> 2154 ds_next_snap_obj); 2155 } else { 2156 zfs_dbgmsg("destroying ds %llu on %s; in queue; " 2157 "removing", 2158 (u_longlong_t)ds->ds_object, 2159 dp->dp_spa->spa_name); 2160 } 2161 } 2162 2163 /* 2164 * dsl_scan_sync() should be called after this, and should sync 2165 * out our changed state, but just to be safe, do it here. 2166 */ 2167 dsl_scan_sync_state(scn, tx, SYNC_CACHED); 2168 } 2169 2170 static void 2171 ds_snapshotted_bookmark(dsl_dataset_t *ds, zbookmark_phys_t *scn_bookmark) 2172 { 2173 if (scn_bookmark->zb_objset == ds->ds_object) { 2174 scn_bookmark->zb_objset = 2175 dsl_dataset_phys(ds)->ds_prev_snap_obj; 2176 zfs_dbgmsg("snapshotting ds %llu on %s; currently traversing; " 2177 "reset zb_objset to %llu", 2178 (u_longlong_t)ds->ds_object, 2179 ds->ds_dir->dd_pool->dp_spa->spa_name, 2180 (u_longlong_t)dsl_dataset_phys(ds)->ds_prev_snap_obj); 2181 } 2182 } 2183 2184 /* 2185 * Called when a dataset is snapshotted. If we were currently traversing 2186 * this snapshot, we reset our bookmark to point at the newly created 2187 * snapshot. We also modify our work queue to remove the old snapshot and 2188 * replace with the new one. 2189 */ 2190 void 2191 dsl_scan_ds_snapshotted(dsl_dataset_t *ds, dmu_tx_t *tx) 2192 { 2193 dsl_pool_t *dp = ds->ds_dir->dd_pool; 2194 dsl_scan_t *scn = dp->dp_scan; 2195 uint64_t mintxg; 2196 2197 if (!dsl_scan_is_running(scn)) 2198 return; 2199 2200 ASSERT(dsl_dataset_phys(ds)->ds_prev_snap_obj != 0); 2201 2202 ds_snapshotted_bookmark(ds, &scn->scn_phys.scn_bookmark); 2203 ds_snapshotted_bookmark(ds, &scn->scn_phys_cached.scn_bookmark); 2204 2205 if (scan_ds_queue_contains(scn, ds->ds_object, &mintxg)) { 2206 scan_ds_queue_remove(scn, ds->ds_object); 2207 scan_ds_queue_insert(scn, 2208 dsl_dataset_phys(ds)->ds_prev_snap_obj, mintxg); 2209 } 2210 2211 if (zap_lookup_int_key(dp->dp_meta_objset, scn->scn_phys.scn_queue_obj, 2212 ds->ds_object, &mintxg) == 0) { 2213 VERIFY3U(0, ==, zap_remove_int(dp->dp_meta_objset, 2214 scn->scn_phys.scn_queue_obj, ds->ds_object, tx)); 2215 VERIFY(zap_add_int_key(dp->dp_meta_objset, 2216 scn->scn_phys.scn_queue_obj, 2217 dsl_dataset_phys(ds)->ds_prev_snap_obj, mintxg, tx) == 0); 2218 zfs_dbgmsg("snapshotting ds %llu on %s; in queue; " 2219 "replacing with %llu", 2220 (u_longlong_t)ds->ds_object, 2221 dp->dp_spa->spa_name, 2222 (u_longlong_t)dsl_dataset_phys(ds)->ds_prev_snap_obj); 2223 } 2224 2225 dsl_scan_sync_state(scn, tx, SYNC_CACHED); 2226 } 2227 2228 static void 2229 ds_clone_swapped_bookmark(dsl_dataset_t *ds1, dsl_dataset_t *ds2, 2230 zbookmark_phys_t *scn_bookmark) 2231 { 2232 if (scn_bookmark->zb_objset == ds1->ds_object) { 2233 scn_bookmark->zb_objset = ds2->ds_object; 2234 zfs_dbgmsg("clone_swap ds %llu on %s; currently traversing; " 2235 "reset zb_objset to %llu", 2236 (u_longlong_t)ds1->ds_object, 2237 ds1->ds_dir->dd_pool->dp_spa->spa_name, 2238 (u_longlong_t)ds2->ds_object); 2239 } else if (scn_bookmark->zb_objset == ds2->ds_object) { 2240 scn_bookmark->zb_objset = ds1->ds_object; 2241 zfs_dbgmsg("clone_swap ds %llu on %s; currently traversing; " 2242 "reset zb_objset to %llu", 2243 (u_longlong_t)ds2->ds_object, 2244 ds2->ds_dir->dd_pool->dp_spa->spa_name, 2245 (u_longlong_t)ds1->ds_object); 2246 } 2247 } 2248 2249 /* 2250 * Called when an origin dataset and its clone are swapped. If we were 2251 * currently traversing the dataset, we need to switch to traversing the 2252 * newly promoted clone. 2253 */ 2254 void 2255 dsl_scan_ds_clone_swapped(dsl_dataset_t *ds1, dsl_dataset_t *ds2, dmu_tx_t *tx) 2256 { 2257 dsl_pool_t *dp = ds1->ds_dir->dd_pool; 2258 dsl_scan_t *scn = dp->dp_scan; 2259 uint64_t mintxg1, mintxg2; 2260 boolean_t ds1_queued, ds2_queued; 2261 2262 if (!dsl_scan_is_running(scn)) 2263 return; 2264 2265 ds_clone_swapped_bookmark(ds1, ds2, &scn->scn_phys.scn_bookmark); 2266 ds_clone_swapped_bookmark(ds1, ds2, &scn->scn_phys_cached.scn_bookmark); 2267 2268 /* 2269 * Handle the in-memory scan queue. 2270 */ 2271 ds1_queued = scan_ds_queue_contains(scn, ds1->ds_object, &mintxg1); 2272 ds2_queued = scan_ds_queue_contains(scn, ds2->ds_object, &mintxg2); 2273 2274 /* Sanity checking. */ 2275 if (ds1_queued) { 2276 ASSERT3U(mintxg1, ==, dsl_dataset_phys(ds1)->ds_prev_snap_txg); 2277 ASSERT3U(mintxg1, ==, dsl_dataset_phys(ds2)->ds_prev_snap_txg); 2278 } 2279 if (ds2_queued) { 2280 ASSERT3U(mintxg2, ==, dsl_dataset_phys(ds1)->ds_prev_snap_txg); 2281 ASSERT3U(mintxg2, ==, dsl_dataset_phys(ds2)->ds_prev_snap_txg); 2282 } 2283 2284 if (ds1_queued && ds2_queued) { 2285 /* 2286 * If both are queued, we don't need to do anything. 2287 * The swapping code below would not handle this case correctly, 2288 * since we can't insert ds2 if it is already there. That's 2289 * because scan_ds_queue_insert() prohibits a duplicate insert 2290 * and panics. 2291 */ 2292 } else if (ds1_queued) { 2293 scan_ds_queue_remove(scn, ds1->ds_object); 2294 scan_ds_queue_insert(scn, ds2->ds_object, mintxg1); 2295 } else if (ds2_queued) { 2296 scan_ds_queue_remove(scn, ds2->ds_object); 2297 scan_ds_queue_insert(scn, ds1->ds_object, mintxg2); 2298 } 2299 2300 /* 2301 * Handle the on-disk scan queue. 2302 * The on-disk state is an out-of-date version of the in-memory state, 2303 * so the in-memory and on-disk values for ds1_queued and ds2_queued may 2304 * be different. Therefore we need to apply the swap logic to the 2305 * on-disk state independently of the in-memory state. 2306 */ 2307 ds1_queued = zap_lookup_int_key(dp->dp_meta_objset, 2308 scn->scn_phys.scn_queue_obj, ds1->ds_object, &mintxg1) == 0; 2309 ds2_queued = zap_lookup_int_key(dp->dp_meta_objset, 2310 scn->scn_phys.scn_queue_obj, ds2->ds_object, &mintxg2) == 0; 2311 2312 /* Sanity checking. */ 2313 if (ds1_queued) { 2314 ASSERT3U(mintxg1, ==, dsl_dataset_phys(ds1)->ds_prev_snap_txg); 2315 ASSERT3U(mintxg1, ==, dsl_dataset_phys(ds2)->ds_prev_snap_txg); 2316 } 2317 if (ds2_queued) { 2318 ASSERT3U(mintxg2, ==, dsl_dataset_phys(ds1)->ds_prev_snap_txg); 2319 ASSERT3U(mintxg2, ==, dsl_dataset_phys(ds2)->ds_prev_snap_txg); 2320 } 2321 2322 if (ds1_queued && ds2_queued) { 2323 /* 2324 * If both are queued, we don't need to do anything. 2325 * Alternatively, we could check for EEXIST from 2326 * zap_add_int_key() and back out to the original state, but 2327 * that would be more work than checking for this case upfront. 2328 */ 2329 } else if (ds1_queued) { 2330 VERIFY3S(0, ==, zap_remove_int(dp->dp_meta_objset, 2331 scn->scn_phys.scn_queue_obj, ds1->ds_object, tx)); 2332 VERIFY3S(0, ==, zap_add_int_key(dp->dp_meta_objset, 2333 scn->scn_phys.scn_queue_obj, ds2->ds_object, mintxg1, tx)); 2334 zfs_dbgmsg("clone_swap ds %llu on %s; in queue; " 2335 "replacing with %llu", 2336 (u_longlong_t)ds1->ds_object, 2337 dp->dp_spa->spa_name, 2338 (u_longlong_t)ds2->ds_object); 2339 } else if (ds2_queued) { 2340 VERIFY3S(0, ==, zap_remove_int(dp->dp_meta_objset, 2341 scn->scn_phys.scn_queue_obj, ds2->ds_object, tx)); 2342 VERIFY3S(0, ==, zap_add_int_key(dp->dp_meta_objset, 2343 scn->scn_phys.scn_queue_obj, ds1->ds_object, mintxg2, tx)); 2344 zfs_dbgmsg("clone_swap ds %llu on %s; in queue; " 2345 "replacing with %llu", 2346 (u_longlong_t)ds2->ds_object, 2347 dp->dp_spa->spa_name, 2348 (u_longlong_t)ds1->ds_object); 2349 } 2350 2351 dsl_scan_sync_state(scn, tx, SYNC_CACHED); 2352 } 2353 2354 static int 2355 enqueue_clones_cb(dsl_pool_t *dp, dsl_dataset_t *hds, void *arg) 2356 { 2357 uint64_t originobj = *(uint64_t *)arg; 2358 dsl_dataset_t *ds; 2359 int err; 2360 dsl_scan_t *scn = dp->dp_scan; 2361 2362 if (dsl_dir_phys(hds->ds_dir)->dd_origin_obj != originobj) 2363 return (0); 2364 2365 err = dsl_dataset_hold_obj(dp, hds->ds_object, FTAG, &ds); 2366 if (err) 2367 return (err); 2368 2369 while (dsl_dataset_phys(ds)->ds_prev_snap_obj != originobj) { 2370 dsl_dataset_t *prev; 2371 err = dsl_dataset_hold_obj(dp, 2372 dsl_dataset_phys(ds)->ds_prev_snap_obj, FTAG, &prev); 2373 2374 dsl_dataset_rele(ds, FTAG); 2375 if (err) 2376 return (err); 2377 ds = prev; 2378 } 2379 scan_ds_queue_insert(scn, ds->ds_object, 2380 dsl_dataset_phys(ds)->ds_prev_snap_txg); 2381 dsl_dataset_rele(ds, FTAG); 2382 return (0); 2383 } 2384 2385 static void 2386 dsl_scan_visitds(dsl_scan_t *scn, uint64_t dsobj, dmu_tx_t *tx) 2387 { 2388 dsl_pool_t *dp = scn->scn_dp; 2389 dsl_dataset_t *ds; 2390 2391 VERIFY3U(0, ==, dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds)); 2392 2393 if (scn->scn_phys.scn_cur_min_txg >= 2394 scn->scn_phys.scn_max_txg) { 2395 /* 2396 * This can happen if this snapshot was created after the 2397 * scan started, and we already completed a previous snapshot 2398 * that was created after the scan started. This snapshot 2399 * only references blocks with: 2400 * 2401 * birth < our ds_creation_txg 2402 * cur_min_txg is no less than ds_creation_txg. 2403 * We have already visited these blocks. 2404 * or 2405 * birth > scn_max_txg 2406 * The scan requested not to visit these blocks. 2407 * 2408 * Subsequent snapshots (and clones) can reference our 2409 * blocks, or blocks with even higher birth times. 2410 * Therefore we do not need to visit them either, 2411 * so we do not add them to the work queue. 2412 * 2413 * Note that checking for cur_min_txg >= cur_max_txg 2414 * is not sufficient, because in that case we may need to 2415 * visit subsequent snapshots. This happens when min_txg > 0, 2416 * which raises cur_min_txg. In this case we will visit 2417 * this dataset but skip all of its blocks, because the 2418 * rootbp's birth time is < cur_min_txg. Then we will 2419 * add the next snapshots/clones to the work queue. 2420 */ 2421 char *dsname = kmem_alloc(ZFS_MAX_DATASET_NAME_LEN, KM_SLEEP); 2422 dsl_dataset_name(ds, dsname); 2423 zfs_dbgmsg("scanning dataset %llu (%s) is unnecessary because " 2424 "cur_min_txg (%llu) >= max_txg (%llu)", 2425 (longlong_t)dsobj, dsname, 2426 (longlong_t)scn->scn_phys.scn_cur_min_txg, 2427 (longlong_t)scn->scn_phys.scn_max_txg); 2428 kmem_free(dsname, MAXNAMELEN); 2429 2430 goto out; 2431 } 2432 2433 /* 2434 * Only the ZIL in the head (non-snapshot) is valid. Even though 2435 * snapshots can have ZIL block pointers (which may be the same 2436 * BP as in the head), they must be ignored. In addition, $ORIGIN 2437 * doesn't have a objset (i.e. its ds_bp is a hole) so we don't 2438 * need to look for a ZIL in it either. So we traverse the ZIL here, 2439 * rather than in scan_recurse(), because the regular snapshot 2440 * block-sharing rules don't apply to it. 2441 */ 2442 if (!dsl_dataset_is_snapshot(ds) && 2443 (dp->dp_origin_snap == NULL || 2444 ds->ds_dir != dp->dp_origin_snap->ds_dir)) { 2445 objset_t *os; 2446 if (dmu_objset_from_ds(ds, &os) != 0) { 2447 goto out; 2448 } 2449 dsl_scan_zil(dp, &os->os_zil_header); 2450 } 2451 2452 /* 2453 * Iterate over the bps in this ds. 2454 */ 2455 dmu_buf_will_dirty(ds->ds_dbuf, tx); 2456 rrw_enter(&ds->ds_bp_rwlock, RW_READER, FTAG); 2457 dsl_scan_visit_rootbp(scn, ds, &dsl_dataset_phys(ds)->ds_bp, tx); 2458 rrw_exit(&ds->ds_bp_rwlock, FTAG); 2459 2460 char *dsname = kmem_alloc(ZFS_MAX_DATASET_NAME_LEN, KM_SLEEP); 2461 dsl_dataset_name(ds, dsname); 2462 zfs_dbgmsg("scanned dataset %llu (%s) with min=%llu max=%llu; " 2463 "suspending=%u", 2464 (longlong_t)dsobj, dsname, 2465 (longlong_t)scn->scn_phys.scn_cur_min_txg, 2466 (longlong_t)scn->scn_phys.scn_cur_max_txg, 2467 (int)scn->scn_suspending); 2468 kmem_free(dsname, ZFS_MAX_DATASET_NAME_LEN); 2469 2470 if (scn->scn_suspending) 2471 goto out; 2472 2473 /* 2474 * We've finished this pass over this dataset. 2475 */ 2476 2477 /* 2478 * If we did not completely visit this dataset, do another pass. 2479 */ 2480 if (scn->scn_phys.scn_flags & DSF_VISIT_DS_AGAIN) { 2481 zfs_dbgmsg("incomplete pass on %s; visiting again", 2482 dp->dp_spa->spa_name); 2483 scn->scn_phys.scn_flags &= ~DSF_VISIT_DS_AGAIN; 2484 scan_ds_queue_insert(scn, ds->ds_object, 2485 scn->scn_phys.scn_cur_max_txg); 2486 goto out; 2487 } 2488 2489 /* 2490 * Add descendant datasets to work queue. 2491 */ 2492 if (dsl_dataset_phys(ds)->ds_next_snap_obj != 0) { 2493 scan_ds_queue_insert(scn, 2494 dsl_dataset_phys(ds)->ds_next_snap_obj, 2495 dsl_dataset_phys(ds)->ds_creation_txg); 2496 } 2497 if (dsl_dataset_phys(ds)->ds_num_children > 1) { 2498 boolean_t usenext = B_FALSE; 2499 if (dsl_dataset_phys(ds)->ds_next_clones_obj != 0) { 2500 uint64_t count; 2501 /* 2502 * A bug in a previous version of the code could 2503 * cause upgrade_clones_cb() to not set 2504 * ds_next_snap_obj when it should, leading to a 2505 * missing entry. Therefore we can only use the 2506 * next_clones_obj when its count is correct. 2507 */ 2508 int err = zap_count(dp->dp_meta_objset, 2509 dsl_dataset_phys(ds)->ds_next_clones_obj, &count); 2510 if (err == 0 && 2511 count == dsl_dataset_phys(ds)->ds_num_children - 1) 2512 usenext = B_TRUE; 2513 } 2514 2515 if (usenext) { 2516 zap_cursor_t zc; 2517 zap_attribute_t za; 2518 for (zap_cursor_init(&zc, dp->dp_meta_objset, 2519 dsl_dataset_phys(ds)->ds_next_clones_obj); 2520 zap_cursor_retrieve(&zc, &za) == 0; 2521 (void) zap_cursor_advance(&zc)) { 2522 scan_ds_queue_insert(scn, 2523 zfs_strtonum(za.za_name, NULL), 2524 dsl_dataset_phys(ds)->ds_creation_txg); 2525 } 2526 zap_cursor_fini(&zc); 2527 } else { 2528 VERIFY0(dmu_objset_find_dp(dp, dp->dp_root_dir_obj, 2529 enqueue_clones_cb, &ds->ds_object, 2530 DS_FIND_CHILDREN)); 2531 } 2532 } 2533 2534 out: 2535 dsl_dataset_rele(ds, FTAG); 2536 } 2537 2538 static int 2539 enqueue_cb(dsl_pool_t *dp, dsl_dataset_t *hds, void *arg) 2540 { 2541 (void) arg; 2542 dsl_dataset_t *ds; 2543 int err; 2544 dsl_scan_t *scn = dp->dp_scan; 2545 2546 err = dsl_dataset_hold_obj(dp, hds->ds_object, FTAG, &ds); 2547 if (err) 2548 return (err); 2549 2550 while (dsl_dataset_phys(ds)->ds_prev_snap_obj != 0) { 2551 dsl_dataset_t *prev; 2552 err = dsl_dataset_hold_obj(dp, 2553 dsl_dataset_phys(ds)->ds_prev_snap_obj, FTAG, &prev); 2554 if (err) { 2555 dsl_dataset_rele(ds, FTAG); 2556 return (err); 2557 } 2558 2559 /* 2560 * If this is a clone, we don't need to worry about it for now. 2561 */ 2562 if (dsl_dataset_phys(prev)->ds_next_snap_obj != ds->ds_object) { 2563 dsl_dataset_rele(ds, FTAG); 2564 dsl_dataset_rele(prev, FTAG); 2565 return (0); 2566 } 2567 dsl_dataset_rele(ds, FTAG); 2568 ds = prev; 2569 } 2570 2571 scan_ds_queue_insert(scn, ds->ds_object, 2572 dsl_dataset_phys(ds)->ds_prev_snap_txg); 2573 dsl_dataset_rele(ds, FTAG); 2574 return (0); 2575 } 2576 2577 void 2578 dsl_scan_ddt_entry(dsl_scan_t *scn, enum zio_checksum checksum, 2579 ddt_entry_t *dde, dmu_tx_t *tx) 2580 { 2581 (void) tx; 2582 const ddt_key_t *ddk = &dde->dde_key; 2583 ddt_phys_t *ddp = dde->dde_phys; 2584 blkptr_t bp; 2585 zbookmark_phys_t zb = { 0 }; 2586 2587 if (!dsl_scan_is_running(scn)) 2588 return; 2589 2590 /* 2591 * This function is special because it is the only thing 2592 * that can add scan_io_t's to the vdev scan queues from 2593 * outside dsl_scan_sync(). For the most part this is ok 2594 * as long as it is called from within syncing context. 2595 * However, dsl_scan_sync() expects that no new sio's will 2596 * be added between when all the work for a scan is done 2597 * and the next txg when the scan is actually marked as 2598 * completed. This check ensures we do not issue new sio's 2599 * during this period. 2600 */ 2601 if (scn->scn_done_txg != 0) 2602 return; 2603 2604 for (int p = 0; p < DDT_PHYS_TYPES; p++, ddp++) { 2605 if (ddp->ddp_phys_birth == 0 || 2606 ddp->ddp_phys_birth > scn->scn_phys.scn_max_txg) 2607 continue; 2608 ddt_bp_create(checksum, ddk, ddp, &bp); 2609 2610 scn->scn_visited_this_txg++; 2611 scan_funcs[scn->scn_phys.scn_func](scn->scn_dp, &bp, &zb); 2612 } 2613 } 2614 2615 /* 2616 * Scrub/dedup interaction. 2617 * 2618 * If there are N references to a deduped block, we don't want to scrub it 2619 * N times -- ideally, we should scrub it exactly once. 2620 * 2621 * We leverage the fact that the dde's replication class (enum ddt_class) 2622 * is ordered from highest replication class (DDT_CLASS_DITTO) to lowest 2623 * (DDT_CLASS_UNIQUE) so that we may walk the DDT in that order. 2624 * 2625 * To prevent excess scrubbing, the scrub begins by walking the DDT 2626 * to find all blocks with refcnt > 1, and scrubs each of these once. 2627 * Since there are two replication classes which contain blocks with 2628 * refcnt > 1, we scrub the highest replication class (DDT_CLASS_DITTO) first. 2629 * Finally the top-down scrub begins, only visiting blocks with refcnt == 1. 2630 * 2631 * There would be nothing more to say if a block's refcnt couldn't change 2632 * during a scrub, but of course it can so we must account for changes 2633 * in a block's replication class. 2634 * 2635 * Here's an example of what can occur: 2636 * 2637 * If a block has refcnt > 1 during the DDT scrub phase, but has refcnt == 1 2638 * when visited during the top-down scrub phase, it will be scrubbed twice. 2639 * This negates our scrub optimization, but is otherwise harmless. 2640 * 2641 * If a block has refcnt == 1 during the DDT scrub phase, but has refcnt > 1 2642 * on each visit during the top-down scrub phase, it will never be scrubbed. 2643 * To catch this, ddt_sync_entry() notifies the scrub code whenever a block's 2644 * reference class transitions to a higher level (i.e DDT_CLASS_UNIQUE to 2645 * DDT_CLASS_DUPLICATE); if it transitions from refcnt == 1 to refcnt > 1 2646 * while a scrub is in progress, it scrubs the block right then. 2647 */ 2648 static void 2649 dsl_scan_ddt(dsl_scan_t *scn, dmu_tx_t *tx) 2650 { 2651 ddt_bookmark_t *ddb = &scn->scn_phys.scn_ddt_bookmark; 2652 ddt_entry_t dde = {{{{0}}}}; 2653 int error; 2654 uint64_t n = 0; 2655 2656 while ((error = ddt_walk(scn->scn_dp->dp_spa, ddb, &dde)) == 0) { 2657 ddt_t *ddt; 2658 2659 if (ddb->ddb_class > scn->scn_phys.scn_ddt_class_max) 2660 break; 2661 dprintf("visiting ddb=%llu/%llu/%llu/%llx\n", 2662 (longlong_t)ddb->ddb_class, 2663 (longlong_t)ddb->ddb_type, 2664 (longlong_t)ddb->ddb_checksum, 2665 (longlong_t)ddb->ddb_cursor); 2666 2667 /* There should be no pending changes to the dedup table */ 2668 ddt = scn->scn_dp->dp_spa->spa_ddt[ddb->ddb_checksum]; 2669 ASSERT(avl_first(&ddt->ddt_tree) == NULL); 2670 2671 dsl_scan_ddt_entry(scn, ddb->ddb_checksum, &dde, tx); 2672 n++; 2673 2674 if (dsl_scan_check_suspend(scn, NULL)) 2675 break; 2676 } 2677 2678 zfs_dbgmsg("scanned %llu ddt entries on %s with class_max = %u; " 2679 "suspending=%u", (longlong_t)n, scn->scn_dp->dp_spa->spa_name, 2680 (int)scn->scn_phys.scn_ddt_class_max, (int)scn->scn_suspending); 2681 2682 ASSERT(error == 0 || error == ENOENT); 2683 ASSERT(error != ENOENT || 2684 ddb->ddb_class > scn->scn_phys.scn_ddt_class_max); 2685 } 2686 2687 static uint64_t 2688 dsl_scan_ds_maxtxg(dsl_dataset_t *ds) 2689 { 2690 uint64_t smt = ds->ds_dir->dd_pool->dp_scan->scn_phys.scn_max_txg; 2691 if (ds->ds_is_snapshot) 2692 return (MIN(smt, dsl_dataset_phys(ds)->ds_creation_txg)); 2693 return (smt); 2694 } 2695 2696 static void 2697 dsl_scan_visit(dsl_scan_t *scn, dmu_tx_t *tx) 2698 { 2699 scan_ds_t *sds; 2700 dsl_pool_t *dp = scn->scn_dp; 2701 2702 if (scn->scn_phys.scn_ddt_bookmark.ddb_class <= 2703 scn->scn_phys.scn_ddt_class_max) { 2704 scn->scn_phys.scn_cur_min_txg = scn->scn_phys.scn_min_txg; 2705 scn->scn_phys.scn_cur_max_txg = scn->scn_phys.scn_max_txg; 2706 dsl_scan_ddt(scn, tx); 2707 if (scn->scn_suspending) 2708 return; 2709 } 2710 2711 if (scn->scn_phys.scn_bookmark.zb_objset == DMU_META_OBJSET) { 2712 /* First do the MOS & ORIGIN */ 2713 2714 scn->scn_phys.scn_cur_min_txg = scn->scn_phys.scn_min_txg; 2715 scn->scn_phys.scn_cur_max_txg = scn->scn_phys.scn_max_txg; 2716 dsl_scan_visit_rootbp(scn, NULL, 2717 &dp->dp_meta_rootbp, tx); 2718 spa_set_rootblkptr(dp->dp_spa, &dp->dp_meta_rootbp); 2719 if (scn->scn_suspending) 2720 return; 2721 2722 if (spa_version(dp->dp_spa) < SPA_VERSION_DSL_SCRUB) { 2723 VERIFY0(dmu_objset_find_dp(dp, dp->dp_root_dir_obj, 2724 enqueue_cb, NULL, DS_FIND_CHILDREN)); 2725 } else { 2726 dsl_scan_visitds(scn, 2727 dp->dp_origin_snap->ds_object, tx); 2728 } 2729 ASSERT(!scn->scn_suspending); 2730 } else if (scn->scn_phys.scn_bookmark.zb_objset != 2731 ZB_DESTROYED_OBJSET) { 2732 uint64_t dsobj = scn->scn_phys.scn_bookmark.zb_objset; 2733 /* 2734 * If we were suspended, continue from here. Note if the 2735 * ds we were suspended on was deleted, the zb_objset may 2736 * be -1, so we will skip this and find a new objset 2737 * below. 2738 */ 2739 dsl_scan_visitds(scn, dsobj, tx); 2740 if (scn->scn_suspending) 2741 return; 2742 } 2743 2744 /* 2745 * In case we suspended right at the end of the ds, zero the 2746 * bookmark so we don't think that we're still trying to resume. 2747 */ 2748 memset(&scn->scn_phys.scn_bookmark, 0, sizeof (zbookmark_phys_t)); 2749 2750 /* 2751 * Keep pulling things out of the dataset avl queue. Updates to the 2752 * persistent zap-object-as-queue happen only at checkpoints. 2753 */ 2754 while ((sds = avl_first(&scn->scn_queue)) != NULL) { 2755 dsl_dataset_t *ds; 2756 uint64_t dsobj = sds->sds_dsobj; 2757 uint64_t txg = sds->sds_txg; 2758 2759 /* dequeue and free the ds from the queue */ 2760 scan_ds_queue_remove(scn, dsobj); 2761 sds = NULL; 2762 2763 /* set up min / max txg */ 2764 VERIFY3U(0, ==, dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds)); 2765 if (txg != 0) { 2766 scn->scn_phys.scn_cur_min_txg = 2767 MAX(scn->scn_phys.scn_min_txg, txg); 2768 } else { 2769 scn->scn_phys.scn_cur_min_txg = 2770 MAX(scn->scn_phys.scn_min_txg, 2771 dsl_dataset_phys(ds)->ds_prev_snap_txg); 2772 } 2773 scn->scn_phys.scn_cur_max_txg = dsl_scan_ds_maxtxg(ds); 2774 dsl_dataset_rele(ds, FTAG); 2775 2776 dsl_scan_visitds(scn, dsobj, tx); 2777 if (scn->scn_suspending) 2778 return; 2779 } 2780 2781 /* No more objsets to fetch, we're done */ 2782 scn->scn_phys.scn_bookmark.zb_objset = ZB_DESTROYED_OBJSET; 2783 ASSERT0(scn->scn_suspending); 2784 } 2785 2786 static uint64_t 2787 dsl_scan_count_data_disks(vdev_t *rvd) 2788 { 2789 uint64_t i, leaves = 0; 2790 2791 for (i = 0; i < rvd->vdev_children; i++) { 2792 vdev_t *vd = rvd->vdev_child[i]; 2793 if (vd->vdev_islog || vd->vdev_isspare || vd->vdev_isl2cache) 2794 continue; 2795 leaves += vdev_get_ndisks(vd) - vdev_get_nparity(vd); 2796 } 2797 return (leaves); 2798 } 2799 2800 static void 2801 scan_io_queues_update_zio_stats(dsl_scan_io_queue_t *q, const blkptr_t *bp) 2802 { 2803 int i; 2804 uint64_t cur_size = 0; 2805 2806 for (i = 0; i < BP_GET_NDVAS(bp); i++) { 2807 cur_size += DVA_GET_ASIZE(&bp->blk_dva[i]); 2808 } 2809 2810 q->q_total_zio_size_this_txg += cur_size; 2811 q->q_zios_this_txg++; 2812 } 2813 2814 static void 2815 scan_io_queues_update_seg_stats(dsl_scan_io_queue_t *q, uint64_t start, 2816 uint64_t end) 2817 { 2818 q->q_total_seg_size_this_txg += end - start; 2819 q->q_segs_this_txg++; 2820 } 2821 2822 static boolean_t 2823 scan_io_queue_check_suspend(dsl_scan_t *scn) 2824 { 2825 /* See comment in dsl_scan_check_suspend() */ 2826 uint64_t curr_time_ns = gethrtime(); 2827 uint64_t scan_time_ns = curr_time_ns - scn->scn_sync_start_time; 2828 uint64_t sync_time_ns = curr_time_ns - 2829 scn->scn_dp->dp_spa->spa_sync_starttime; 2830 int dirty_pct = scn->scn_dp->dp_dirty_total * 100 / zfs_dirty_data_max; 2831 int mintime = (scn->scn_phys.scn_func == POOL_SCAN_RESILVER) ? 2832 zfs_resilver_min_time_ms : zfs_scrub_min_time_ms; 2833 2834 return ((NSEC2MSEC(scan_time_ns) > mintime && 2835 (dirty_pct >= zfs_vdev_async_write_active_min_dirty_percent || 2836 txg_sync_waiting(scn->scn_dp) || 2837 NSEC2SEC(sync_time_ns) >= zfs_txg_timeout)) || 2838 spa_shutting_down(scn->scn_dp->dp_spa)); 2839 } 2840 2841 /* 2842 * Given a list of scan_io_t's in io_list, this issues the I/Os out to 2843 * disk. This consumes the io_list and frees the scan_io_t's. This is 2844 * called when emptying queues, either when we're up against the memory 2845 * limit or when we have finished scanning. Returns B_TRUE if we stopped 2846 * processing the list before we finished. Any sios that were not issued 2847 * will remain in the io_list. 2848 */ 2849 static boolean_t 2850 scan_io_queue_issue(dsl_scan_io_queue_t *queue, list_t *io_list) 2851 { 2852 dsl_scan_t *scn = queue->q_scn; 2853 scan_io_t *sio; 2854 int64_t bytes_issued = 0; 2855 boolean_t suspended = B_FALSE; 2856 2857 while ((sio = list_head(io_list)) != NULL) { 2858 blkptr_t bp; 2859 2860 if (scan_io_queue_check_suspend(scn)) { 2861 suspended = B_TRUE; 2862 break; 2863 } 2864 2865 sio2bp(sio, &bp); 2866 bytes_issued += SIO_GET_ASIZE(sio); 2867 scan_exec_io(scn->scn_dp, &bp, sio->sio_flags, 2868 &sio->sio_zb, queue); 2869 (void) list_remove_head(io_list); 2870 scan_io_queues_update_zio_stats(queue, &bp); 2871 sio_free(sio); 2872 } 2873 2874 atomic_add_64(&scn->scn_bytes_pending, -bytes_issued); 2875 2876 return (suspended); 2877 } 2878 2879 /* 2880 * This function removes sios from an IO queue which reside within a given 2881 * range_seg_t and inserts them (in offset order) into a list. Note that 2882 * we only ever return a maximum of 32 sios at once. If there are more sios 2883 * to process within this segment that did not make it onto the list we 2884 * return B_TRUE and otherwise B_FALSE. 2885 */ 2886 static boolean_t 2887 scan_io_queue_gather(dsl_scan_io_queue_t *queue, range_seg_t *rs, list_t *list) 2888 { 2889 scan_io_t *srch_sio, *sio, *next_sio; 2890 avl_index_t idx; 2891 uint_t num_sios = 0; 2892 int64_t bytes_issued = 0; 2893 2894 ASSERT(rs != NULL); 2895 ASSERT(MUTEX_HELD(&queue->q_vd->vdev_scan_io_queue_lock)); 2896 2897 srch_sio = sio_alloc(1); 2898 srch_sio->sio_nr_dvas = 1; 2899 SIO_SET_OFFSET(srch_sio, rs_get_start(rs, queue->q_exts_by_addr)); 2900 2901 /* 2902 * The exact start of the extent might not contain any matching zios, 2903 * so if that's the case, examine the next one in the tree. 2904 */ 2905 sio = avl_find(&queue->q_sios_by_addr, srch_sio, &idx); 2906 sio_free(srch_sio); 2907 2908 if (sio == NULL) 2909 sio = avl_nearest(&queue->q_sios_by_addr, idx, AVL_AFTER); 2910 2911 while (sio != NULL && SIO_GET_OFFSET(sio) < rs_get_end(rs, 2912 queue->q_exts_by_addr) && num_sios <= 32) { 2913 ASSERT3U(SIO_GET_OFFSET(sio), >=, rs_get_start(rs, 2914 queue->q_exts_by_addr)); 2915 ASSERT3U(SIO_GET_END_OFFSET(sio), <=, rs_get_end(rs, 2916 queue->q_exts_by_addr)); 2917 2918 next_sio = AVL_NEXT(&queue->q_sios_by_addr, sio); 2919 avl_remove(&queue->q_sios_by_addr, sio); 2920 queue->q_sio_memused -= SIO_GET_MUSED(sio); 2921 2922 bytes_issued += SIO_GET_ASIZE(sio); 2923 num_sios++; 2924 list_insert_tail(list, sio); 2925 sio = next_sio; 2926 } 2927 2928 /* 2929 * We limit the number of sios we process at once to 32 to avoid 2930 * biting off more than we can chew. If we didn't take everything 2931 * in the segment we update it to reflect the work we were able to 2932 * complete. Otherwise, we remove it from the range tree entirely. 2933 */ 2934 if (sio != NULL && SIO_GET_OFFSET(sio) < rs_get_end(rs, 2935 queue->q_exts_by_addr)) { 2936 range_tree_adjust_fill(queue->q_exts_by_addr, rs, 2937 -bytes_issued); 2938 range_tree_resize_segment(queue->q_exts_by_addr, rs, 2939 SIO_GET_OFFSET(sio), rs_get_end(rs, 2940 queue->q_exts_by_addr) - SIO_GET_OFFSET(sio)); 2941 2942 return (B_TRUE); 2943 } else { 2944 uint64_t rstart = rs_get_start(rs, queue->q_exts_by_addr); 2945 uint64_t rend = rs_get_end(rs, queue->q_exts_by_addr); 2946 range_tree_remove(queue->q_exts_by_addr, rstart, rend - rstart); 2947 return (B_FALSE); 2948 } 2949 } 2950 2951 /* 2952 * This is called from the queue emptying thread and selects the next 2953 * extent from which we are to issue I/Os. The behavior of this function 2954 * depends on the state of the scan, the current memory consumption and 2955 * whether or not we are performing a scan shutdown. 2956 * 1) We select extents in an elevator algorithm (LBA-order) if the scan 2957 * needs to perform a checkpoint 2958 * 2) We select the largest available extent if we are up against the 2959 * memory limit. 2960 * 3) Otherwise we don't select any extents. 2961 */ 2962 static range_seg_t * 2963 scan_io_queue_fetch_ext(dsl_scan_io_queue_t *queue) 2964 { 2965 dsl_scan_t *scn = queue->q_scn; 2966 range_tree_t *rt = queue->q_exts_by_addr; 2967 2968 ASSERT(MUTEX_HELD(&queue->q_vd->vdev_scan_io_queue_lock)); 2969 ASSERT(scn->scn_is_sorted); 2970 2971 /* handle tunable overrides */ 2972 if (scn->scn_checkpointing || scn->scn_clearing) { 2973 if (zfs_scan_issue_strategy == 1) { 2974 return (range_tree_first(rt)); 2975 } else if (zfs_scan_issue_strategy == 2) { 2976 /* 2977 * We need to get the original entry in the by_addr 2978 * tree so we can modify it. 2979 */ 2980 range_seg_t *size_rs = 2981 zfs_btree_first(&queue->q_exts_by_size, NULL); 2982 if (size_rs == NULL) 2983 return (NULL); 2984 uint64_t start = rs_get_start(size_rs, rt); 2985 uint64_t size = rs_get_end(size_rs, rt) - start; 2986 range_seg_t *addr_rs = range_tree_find(rt, start, 2987 size); 2988 ASSERT3P(addr_rs, !=, NULL); 2989 ASSERT3U(rs_get_start(size_rs, rt), ==, 2990 rs_get_start(addr_rs, rt)); 2991 ASSERT3U(rs_get_end(size_rs, rt), ==, 2992 rs_get_end(addr_rs, rt)); 2993 return (addr_rs); 2994 } 2995 } 2996 2997 /* 2998 * During normal clearing, we want to issue our largest segments 2999 * first, keeping IO as sequential as possible, and leaving the 3000 * smaller extents for later with the hope that they might eventually 3001 * grow to larger sequential segments. However, when the scan is 3002 * checkpointing, no new extents will be added to the sorting queue, 3003 * so the way we are sorted now is as good as it will ever get. 3004 * In this case, we instead switch to issuing extents in LBA order. 3005 */ 3006 if (scn->scn_checkpointing) { 3007 return (range_tree_first(rt)); 3008 } else if (scn->scn_clearing) { 3009 /* 3010 * We need to get the original entry in the by_addr 3011 * tree so we can modify it. 3012 */ 3013 range_seg_t *size_rs = zfs_btree_first(&queue->q_exts_by_size, 3014 NULL); 3015 if (size_rs == NULL) 3016 return (NULL); 3017 uint64_t start = rs_get_start(size_rs, rt); 3018 uint64_t size = rs_get_end(size_rs, rt) - start; 3019 range_seg_t *addr_rs = range_tree_find(rt, start, size); 3020 ASSERT3P(addr_rs, !=, NULL); 3021 ASSERT3U(rs_get_start(size_rs, rt), ==, rs_get_start(addr_rs, 3022 rt)); 3023 ASSERT3U(rs_get_end(size_rs, rt), ==, rs_get_end(addr_rs, rt)); 3024 return (addr_rs); 3025 } else { 3026 return (NULL); 3027 } 3028 } 3029 3030 static void 3031 scan_io_queues_run_one(void *arg) 3032 { 3033 dsl_scan_io_queue_t *queue = arg; 3034 kmutex_t *q_lock = &queue->q_vd->vdev_scan_io_queue_lock; 3035 boolean_t suspended = B_FALSE; 3036 range_seg_t *rs = NULL; 3037 scan_io_t *sio = NULL; 3038 list_t sio_list; 3039 3040 ASSERT(queue->q_scn->scn_is_sorted); 3041 3042 list_create(&sio_list, sizeof (scan_io_t), 3043 offsetof(scan_io_t, sio_nodes.sio_list_node)); 3044 mutex_enter(q_lock); 3045 3046 /* Calculate maximum in-flight bytes for this vdev. */ 3047 queue->q_maxinflight_bytes = MAX(1, zfs_scan_vdev_limit * 3048 (vdev_get_ndisks(queue->q_vd) - vdev_get_nparity(queue->q_vd))); 3049 3050 /* reset per-queue scan statistics for this txg */ 3051 queue->q_total_seg_size_this_txg = 0; 3052 queue->q_segs_this_txg = 0; 3053 queue->q_total_zio_size_this_txg = 0; 3054 queue->q_zios_this_txg = 0; 3055 3056 /* loop until we run out of time or sios */ 3057 while ((rs = scan_io_queue_fetch_ext(queue)) != NULL) { 3058 uint64_t seg_start = 0, seg_end = 0; 3059 boolean_t more_left = B_TRUE; 3060 3061 ASSERT(list_is_empty(&sio_list)); 3062 3063 /* loop while we still have sios left to process in this rs */ 3064 while (more_left) { 3065 scan_io_t *first_sio, *last_sio; 3066 3067 /* 3068 * We have selected which extent needs to be 3069 * processed next. Gather up the corresponding sios. 3070 */ 3071 more_left = scan_io_queue_gather(queue, rs, &sio_list); 3072 ASSERT(!list_is_empty(&sio_list)); 3073 first_sio = list_head(&sio_list); 3074 last_sio = list_tail(&sio_list); 3075 3076 seg_end = SIO_GET_END_OFFSET(last_sio); 3077 if (seg_start == 0) 3078 seg_start = SIO_GET_OFFSET(first_sio); 3079 3080 /* 3081 * Issuing sios can take a long time so drop the 3082 * queue lock. The sio queue won't be updated by 3083 * other threads since we're in syncing context so 3084 * we can be sure that our trees will remain exactly 3085 * as we left them. 3086 */ 3087 mutex_exit(q_lock); 3088 suspended = scan_io_queue_issue(queue, &sio_list); 3089 mutex_enter(q_lock); 3090 3091 if (suspended) 3092 break; 3093 } 3094 3095 /* update statistics for debugging purposes */ 3096 scan_io_queues_update_seg_stats(queue, seg_start, seg_end); 3097 3098 if (suspended) 3099 break; 3100 } 3101 3102 /* 3103 * If we were suspended in the middle of processing, 3104 * requeue any unfinished sios and exit. 3105 */ 3106 while ((sio = list_head(&sio_list)) != NULL) { 3107 list_remove(&sio_list, sio); 3108 scan_io_queue_insert_impl(queue, sio); 3109 } 3110 3111 mutex_exit(q_lock); 3112 list_destroy(&sio_list); 3113 } 3114 3115 /* 3116 * Performs an emptying run on all scan queues in the pool. This just 3117 * punches out one thread per top-level vdev, each of which processes 3118 * only that vdev's scan queue. We can parallelize the I/O here because 3119 * we know that each queue's I/Os only affect its own top-level vdev. 3120 * 3121 * This function waits for the queue runs to complete, and must be 3122 * called from dsl_scan_sync (or in general, syncing context). 3123 */ 3124 static void 3125 scan_io_queues_run(dsl_scan_t *scn) 3126 { 3127 spa_t *spa = scn->scn_dp->dp_spa; 3128 3129 ASSERT(scn->scn_is_sorted); 3130 ASSERT(spa_config_held(spa, SCL_CONFIG, RW_READER)); 3131 3132 if (scn->scn_bytes_pending == 0) 3133 return; 3134 3135 if (scn->scn_taskq == NULL) { 3136 int nthreads = spa->spa_root_vdev->vdev_children; 3137 3138 /* 3139 * We need to make this taskq *always* execute as many 3140 * threads in parallel as we have top-level vdevs and no 3141 * less, otherwise strange serialization of the calls to 3142 * scan_io_queues_run_one can occur during spa_sync runs 3143 * and that significantly impacts performance. 3144 */ 3145 scn->scn_taskq = taskq_create("dsl_scan_iss", nthreads, 3146 minclsyspri, nthreads, nthreads, TASKQ_PREPOPULATE); 3147 } 3148 3149 for (uint64_t i = 0; i < spa->spa_root_vdev->vdev_children; i++) { 3150 vdev_t *vd = spa->spa_root_vdev->vdev_child[i]; 3151 3152 mutex_enter(&vd->vdev_scan_io_queue_lock); 3153 if (vd->vdev_scan_io_queue != NULL) { 3154 VERIFY(taskq_dispatch(scn->scn_taskq, 3155 scan_io_queues_run_one, vd->vdev_scan_io_queue, 3156 TQ_SLEEP) != TASKQID_INVALID); 3157 } 3158 mutex_exit(&vd->vdev_scan_io_queue_lock); 3159 } 3160 3161 /* 3162 * Wait for the queues to finish issuing their IOs for this run 3163 * before we return. There may still be IOs in flight at this 3164 * point. 3165 */ 3166 taskq_wait(scn->scn_taskq); 3167 } 3168 3169 static boolean_t 3170 dsl_scan_async_block_should_pause(dsl_scan_t *scn) 3171 { 3172 uint64_t elapsed_nanosecs; 3173 3174 if (zfs_recover) 3175 return (B_FALSE); 3176 3177 if (zfs_async_block_max_blocks != 0 && 3178 scn->scn_visited_this_txg >= zfs_async_block_max_blocks) { 3179 return (B_TRUE); 3180 } 3181 3182 if (zfs_max_async_dedup_frees != 0 && 3183 scn->scn_dedup_frees_this_txg >= zfs_max_async_dedup_frees) { 3184 return (B_TRUE); 3185 } 3186 3187 elapsed_nanosecs = gethrtime() - scn->scn_sync_start_time; 3188 return (elapsed_nanosecs / NANOSEC > zfs_txg_timeout || 3189 (NSEC2MSEC(elapsed_nanosecs) > scn->scn_async_block_min_time_ms && 3190 txg_sync_waiting(scn->scn_dp)) || 3191 spa_shutting_down(scn->scn_dp->dp_spa)); 3192 } 3193 3194 static int 3195 dsl_scan_free_block_cb(void *arg, const blkptr_t *bp, dmu_tx_t *tx) 3196 { 3197 dsl_scan_t *scn = arg; 3198 3199 if (!scn->scn_is_bptree || 3200 (BP_GET_LEVEL(bp) == 0 && BP_GET_TYPE(bp) != DMU_OT_OBJSET)) { 3201 if (dsl_scan_async_block_should_pause(scn)) 3202 return (SET_ERROR(ERESTART)); 3203 } 3204 3205 zio_nowait(zio_free_sync(scn->scn_zio_root, scn->scn_dp->dp_spa, 3206 dmu_tx_get_txg(tx), bp, 0)); 3207 dsl_dir_diduse_space(tx->tx_pool->dp_free_dir, DD_USED_HEAD, 3208 -bp_get_dsize_sync(scn->scn_dp->dp_spa, bp), 3209 -BP_GET_PSIZE(bp), -BP_GET_UCSIZE(bp), tx); 3210 scn->scn_visited_this_txg++; 3211 if (BP_GET_DEDUP(bp)) 3212 scn->scn_dedup_frees_this_txg++; 3213 return (0); 3214 } 3215 3216 static void 3217 dsl_scan_update_stats(dsl_scan_t *scn) 3218 { 3219 spa_t *spa = scn->scn_dp->dp_spa; 3220 uint64_t i; 3221 uint64_t seg_size_total = 0, zio_size_total = 0; 3222 uint64_t seg_count_total = 0, zio_count_total = 0; 3223 3224 for (i = 0; i < spa->spa_root_vdev->vdev_children; i++) { 3225 vdev_t *vd = spa->spa_root_vdev->vdev_child[i]; 3226 dsl_scan_io_queue_t *queue = vd->vdev_scan_io_queue; 3227 3228 if (queue == NULL) 3229 continue; 3230 3231 seg_size_total += queue->q_total_seg_size_this_txg; 3232 zio_size_total += queue->q_total_zio_size_this_txg; 3233 seg_count_total += queue->q_segs_this_txg; 3234 zio_count_total += queue->q_zios_this_txg; 3235 } 3236 3237 if (seg_count_total == 0 || zio_count_total == 0) { 3238 scn->scn_avg_seg_size_this_txg = 0; 3239 scn->scn_avg_zio_size_this_txg = 0; 3240 scn->scn_segs_this_txg = 0; 3241 scn->scn_zios_this_txg = 0; 3242 return; 3243 } 3244 3245 scn->scn_avg_seg_size_this_txg = seg_size_total / seg_count_total; 3246 scn->scn_avg_zio_size_this_txg = zio_size_total / zio_count_total; 3247 scn->scn_segs_this_txg = seg_count_total; 3248 scn->scn_zios_this_txg = zio_count_total; 3249 } 3250 3251 static int 3252 bpobj_dsl_scan_free_block_cb(void *arg, const blkptr_t *bp, boolean_t bp_freed, 3253 dmu_tx_t *tx) 3254 { 3255 ASSERT(!bp_freed); 3256 return (dsl_scan_free_block_cb(arg, bp, tx)); 3257 } 3258 3259 static int 3260 dsl_scan_obsolete_block_cb(void *arg, const blkptr_t *bp, boolean_t bp_freed, 3261 dmu_tx_t *tx) 3262 { 3263 ASSERT(!bp_freed); 3264 dsl_scan_t *scn = arg; 3265 const dva_t *dva = &bp->blk_dva[0]; 3266 3267 if (dsl_scan_async_block_should_pause(scn)) 3268 return (SET_ERROR(ERESTART)); 3269 3270 spa_vdev_indirect_mark_obsolete(scn->scn_dp->dp_spa, 3271 DVA_GET_VDEV(dva), DVA_GET_OFFSET(dva), 3272 DVA_GET_ASIZE(dva), tx); 3273 scn->scn_visited_this_txg++; 3274 return (0); 3275 } 3276 3277 boolean_t 3278 dsl_scan_active(dsl_scan_t *scn) 3279 { 3280 spa_t *spa = scn->scn_dp->dp_spa; 3281 uint64_t used = 0, comp, uncomp; 3282 boolean_t clones_left; 3283 3284 if (spa->spa_load_state != SPA_LOAD_NONE) 3285 return (B_FALSE); 3286 if (spa_shutting_down(spa)) 3287 return (B_FALSE); 3288 if ((dsl_scan_is_running(scn) && !dsl_scan_is_paused_scrub(scn)) || 3289 (scn->scn_async_destroying && !scn->scn_async_stalled)) 3290 return (B_TRUE); 3291 3292 if (spa_version(scn->scn_dp->dp_spa) >= SPA_VERSION_DEADLISTS) { 3293 (void) bpobj_space(&scn->scn_dp->dp_free_bpobj, 3294 &used, &comp, &uncomp); 3295 } 3296 clones_left = spa_livelist_delete_check(spa); 3297 return ((used != 0) || (clones_left)); 3298 } 3299 3300 static boolean_t 3301 dsl_scan_check_deferred(vdev_t *vd) 3302 { 3303 boolean_t need_resilver = B_FALSE; 3304 3305 for (int c = 0; c < vd->vdev_children; c++) { 3306 need_resilver |= 3307 dsl_scan_check_deferred(vd->vdev_child[c]); 3308 } 3309 3310 if (!vdev_is_concrete(vd) || vd->vdev_aux || 3311 !vd->vdev_ops->vdev_op_leaf) 3312 return (need_resilver); 3313 3314 if (!vd->vdev_resilver_deferred) 3315 need_resilver = B_TRUE; 3316 3317 return (need_resilver); 3318 } 3319 3320 static boolean_t 3321 dsl_scan_need_resilver(spa_t *spa, const dva_t *dva, size_t psize, 3322 uint64_t phys_birth) 3323 { 3324 vdev_t *vd; 3325 3326 vd = vdev_lookup_top(spa, DVA_GET_VDEV(dva)); 3327 3328 if (vd->vdev_ops == &vdev_indirect_ops) { 3329 /* 3330 * The indirect vdev can point to multiple 3331 * vdevs. For simplicity, always create 3332 * the resilver zio_t. zio_vdev_io_start() 3333 * will bypass the child resilver i/o's if 3334 * they are on vdevs that don't have DTL's. 3335 */ 3336 return (B_TRUE); 3337 } 3338 3339 if (DVA_GET_GANG(dva)) { 3340 /* 3341 * Gang members may be spread across multiple 3342 * vdevs, so the best estimate we have is the 3343 * scrub range, which has already been checked. 3344 * XXX -- it would be better to change our 3345 * allocation policy to ensure that all 3346 * gang members reside on the same vdev. 3347 */ 3348 return (B_TRUE); 3349 } 3350 3351 /* 3352 * Check if the top-level vdev must resilver this offset. 3353 * When the offset does not intersect with a dirty leaf DTL 3354 * then it may be possible to skip the resilver IO. The psize 3355 * is provided instead of asize to simplify the check for RAIDZ. 3356 */ 3357 if (!vdev_dtl_need_resilver(vd, dva, psize, phys_birth)) 3358 return (B_FALSE); 3359 3360 /* 3361 * Check that this top-level vdev has a device under it which 3362 * is resilvering and is not deferred. 3363 */ 3364 if (!dsl_scan_check_deferred(vd)) 3365 return (B_FALSE); 3366 3367 return (B_TRUE); 3368 } 3369 3370 static int 3371 dsl_process_async_destroys(dsl_pool_t *dp, dmu_tx_t *tx) 3372 { 3373 dsl_scan_t *scn = dp->dp_scan; 3374 spa_t *spa = dp->dp_spa; 3375 int err = 0; 3376 3377 if (spa_suspend_async_destroy(spa)) 3378 return (0); 3379 3380 if (zfs_free_bpobj_enabled && 3381 spa_version(spa) >= SPA_VERSION_DEADLISTS) { 3382 scn->scn_is_bptree = B_FALSE; 3383 scn->scn_async_block_min_time_ms = zfs_free_min_time_ms; 3384 scn->scn_zio_root = zio_root(spa, NULL, 3385 NULL, ZIO_FLAG_MUSTSUCCEED); 3386 err = bpobj_iterate(&dp->dp_free_bpobj, 3387 bpobj_dsl_scan_free_block_cb, scn, tx); 3388 VERIFY0(zio_wait(scn->scn_zio_root)); 3389 scn->scn_zio_root = NULL; 3390 3391 if (err != 0 && err != ERESTART) 3392 zfs_panic_recover("error %u from bpobj_iterate()", err); 3393 } 3394 3395 if (err == 0 && spa_feature_is_active(spa, SPA_FEATURE_ASYNC_DESTROY)) { 3396 ASSERT(scn->scn_async_destroying); 3397 scn->scn_is_bptree = B_TRUE; 3398 scn->scn_zio_root = zio_root(spa, NULL, 3399 NULL, ZIO_FLAG_MUSTSUCCEED); 3400 err = bptree_iterate(dp->dp_meta_objset, 3401 dp->dp_bptree_obj, B_TRUE, dsl_scan_free_block_cb, scn, tx); 3402 VERIFY0(zio_wait(scn->scn_zio_root)); 3403 scn->scn_zio_root = NULL; 3404 3405 if (err == EIO || err == ECKSUM) { 3406 err = 0; 3407 } else if (err != 0 && err != ERESTART) { 3408 zfs_panic_recover("error %u from " 3409 "traverse_dataset_destroyed()", err); 3410 } 3411 3412 if (bptree_is_empty(dp->dp_meta_objset, dp->dp_bptree_obj)) { 3413 /* finished; deactivate async destroy feature */ 3414 spa_feature_decr(spa, SPA_FEATURE_ASYNC_DESTROY, tx); 3415 ASSERT(!spa_feature_is_active(spa, 3416 SPA_FEATURE_ASYNC_DESTROY)); 3417 VERIFY0(zap_remove(dp->dp_meta_objset, 3418 DMU_POOL_DIRECTORY_OBJECT, 3419 DMU_POOL_BPTREE_OBJ, tx)); 3420 VERIFY0(bptree_free(dp->dp_meta_objset, 3421 dp->dp_bptree_obj, tx)); 3422 dp->dp_bptree_obj = 0; 3423 scn->scn_async_destroying = B_FALSE; 3424 scn->scn_async_stalled = B_FALSE; 3425 } else { 3426 /* 3427 * If we didn't make progress, mark the async 3428 * destroy as stalled, so that we will not initiate 3429 * a spa_sync() on its behalf. Note that we only 3430 * check this if we are not finished, because if the 3431 * bptree had no blocks for us to visit, we can 3432 * finish without "making progress". 3433 */ 3434 scn->scn_async_stalled = 3435 (scn->scn_visited_this_txg == 0); 3436 } 3437 } 3438 if (scn->scn_visited_this_txg) { 3439 zfs_dbgmsg("freed %llu blocks in %llums from " 3440 "free_bpobj/bptree on %s in txg %llu; err=%u", 3441 (longlong_t)scn->scn_visited_this_txg, 3442 (longlong_t) 3443 NSEC2MSEC(gethrtime() - scn->scn_sync_start_time), 3444 spa->spa_name, (longlong_t)tx->tx_txg, err); 3445 scn->scn_visited_this_txg = 0; 3446 scn->scn_dedup_frees_this_txg = 0; 3447 3448 /* 3449 * Write out changes to the DDT that may be required as a 3450 * result of the blocks freed. This ensures that the DDT 3451 * is clean when a scrub/resilver runs. 3452 */ 3453 ddt_sync(spa, tx->tx_txg); 3454 } 3455 if (err != 0) 3456 return (err); 3457 if (dp->dp_free_dir != NULL && !scn->scn_async_destroying && 3458 zfs_free_leak_on_eio && 3459 (dsl_dir_phys(dp->dp_free_dir)->dd_used_bytes != 0 || 3460 dsl_dir_phys(dp->dp_free_dir)->dd_compressed_bytes != 0 || 3461 dsl_dir_phys(dp->dp_free_dir)->dd_uncompressed_bytes != 0)) { 3462 /* 3463 * We have finished background destroying, but there is still 3464 * some space left in the dp_free_dir. Transfer this leaked 3465 * space to the dp_leak_dir. 3466 */ 3467 if (dp->dp_leak_dir == NULL) { 3468 rrw_enter(&dp->dp_config_rwlock, RW_WRITER, FTAG); 3469 (void) dsl_dir_create_sync(dp, dp->dp_root_dir, 3470 LEAK_DIR_NAME, tx); 3471 VERIFY0(dsl_pool_open_special_dir(dp, 3472 LEAK_DIR_NAME, &dp->dp_leak_dir)); 3473 rrw_exit(&dp->dp_config_rwlock, FTAG); 3474 } 3475 dsl_dir_diduse_space(dp->dp_leak_dir, DD_USED_HEAD, 3476 dsl_dir_phys(dp->dp_free_dir)->dd_used_bytes, 3477 dsl_dir_phys(dp->dp_free_dir)->dd_compressed_bytes, 3478 dsl_dir_phys(dp->dp_free_dir)->dd_uncompressed_bytes, tx); 3479 dsl_dir_diduse_space(dp->dp_free_dir, DD_USED_HEAD, 3480 -dsl_dir_phys(dp->dp_free_dir)->dd_used_bytes, 3481 -dsl_dir_phys(dp->dp_free_dir)->dd_compressed_bytes, 3482 -dsl_dir_phys(dp->dp_free_dir)->dd_uncompressed_bytes, tx); 3483 } 3484 3485 if (dp->dp_free_dir != NULL && !scn->scn_async_destroying && 3486 !spa_livelist_delete_check(spa)) { 3487 /* finished; verify that space accounting went to zero */ 3488 ASSERT0(dsl_dir_phys(dp->dp_free_dir)->dd_used_bytes); 3489 ASSERT0(dsl_dir_phys(dp->dp_free_dir)->dd_compressed_bytes); 3490 ASSERT0(dsl_dir_phys(dp->dp_free_dir)->dd_uncompressed_bytes); 3491 } 3492 3493 spa_notify_waiters(spa); 3494 3495 EQUIV(bpobj_is_open(&dp->dp_obsolete_bpobj), 3496 0 == zap_contains(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT, 3497 DMU_POOL_OBSOLETE_BPOBJ)); 3498 if (err == 0 && bpobj_is_open(&dp->dp_obsolete_bpobj)) { 3499 ASSERT(spa_feature_is_active(dp->dp_spa, 3500 SPA_FEATURE_OBSOLETE_COUNTS)); 3501 3502 scn->scn_is_bptree = B_FALSE; 3503 scn->scn_async_block_min_time_ms = zfs_obsolete_min_time_ms; 3504 err = bpobj_iterate(&dp->dp_obsolete_bpobj, 3505 dsl_scan_obsolete_block_cb, scn, tx); 3506 if (err != 0 && err != ERESTART) 3507 zfs_panic_recover("error %u from bpobj_iterate()", err); 3508 3509 if (bpobj_is_empty(&dp->dp_obsolete_bpobj)) 3510 dsl_pool_destroy_obsolete_bpobj(dp, tx); 3511 } 3512 return (0); 3513 } 3514 3515 /* 3516 * This is the primary entry point for scans that is called from syncing 3517 * context. Scans must happen entirely during syncing context so that we 3518 * can guarantee that blocks we are currently scanning will not change out 3519 * from under us. While a scan is active, this function controls how quickly 3520 * transaction groups proceed, instead of the normal handling provided by 3521 * txg_sync_thread(). 3522 */ 3523 void 3524 dsl_scan_sync(dsl_pool_t *dp, dmu_tx_t *tx) 3525 { 3526 int err = 0; 3527 dsl_scan_t *scn = dp->dp_scan; 3528 spa_t *spa = dp->dp_spa; 3529 state_sync_type_t sync_type = SYNC_OPTIONAL; 3530 3531 if (spa->spa_resilver_deferred && 3532 !spa_feature_is_active(dp->dp_spa, SPA_FEATURE_RESILVER_DEFER)) 3533 spa_feature_incr(spa, SPA_FEATURE_RESILVER_DEFER, tx); 3534 3535 /* 3536 * Check for scn_restart_txg before checking spa_load_state, so 3537 * that we can restart an old-style scan while the pool is being 3538 * imported (see dsl_scan_init). We also restart scans if there 3539 * is a deferred resilver and the user has manually disabled 3540 * deferred resilvers via the tunable. 3541 */ 3542 if (dsl_scan_restarting(scn, tx) || 3543 (spa->spa_resilver_deferred && zfs_resilver_disable_defer)) { 3544 pool_scan_func_t func = POOL_SCAN_SCRUB; 3545 dsl_scan_done(scn, B_FALSE, tx); 3546 if (vdev_resilver_needed(spa->spa_root_vdev, NULL, NULL)) 3547 func = POOL_SCAN_RESILVER; 3548 zfs_dbgmsg("restarting scan func=%u on %s txg=%llu", 3549 func, dp->dp_spa->spa_name, (longlong_t)tx->tx_txg); 3550 dsl_scan_setup_sync(&func, tx); 3551 } 3552 3553 /* 3554 * Only process scans in sync pass 1. 3555 */ 3556 if (spa_sync_pass(spa) > 1) 3557 return; 3558 3559 /* 3560 * If the spa is shutting down, then stop scanning. This will 3561 * ensure that the scan does not dirty any new data during the 3562 * shutdown phase. 3563 */ 3564 if (spa_shutting_down(spa)) 3565 return; 3566 3567 /* 3568 * If the scan is inactive due to a stalled async destroy, try again. 3569 */ 3570 if (!scn->scn_async_stalled && !dsl_scan_active(scn)) 3571 return; 3572 3573 /* reset scan statistics */ 3574 scn->scn_visited_this_txg = 0; 3575 scn->scn_dedup_frees_this_txg = 0; 3576 scn->scn_holes_this_txg = 0; 3577 scn->scn_lt_min_this_txg = 0; 3578 scn->scn_gt_max_this_txg = 0; 3579 scn->scn_ddt_contained_this_txg = 0; 3580 scn->scn_objsets_visited_this_txg = 0; 3581 scn->scn_avg_seg_size_this_txg = 0; 3582 scn->scn_segs_this_txg = 0; 3583 scn->scn_avg_zio_size_this_txg = 0; 3584 scn->scn_zios_this_txg = 0; 3585 scn->scn_suspending = B_FALSE; 3586 scn->scn_sync_start_time = gethrtime(); 3587 spa->spa_scrub_active = B_TRUE; 3588 3589 /* 3590 * First process the async destroys. If we suspend, don't do 3591 * any scrubbing or resilvering. This ensures that there are no 3592 * async destroys while we are scanning, so the scan code doesn't 3593 * have to worry about traversing it. It is also faster to free the 3594 * blocks than to scrub them. 3595 */ 3596 err = dsl_process_async_destroys(dp, tx); 3597 if (err != 0) 3598 return; 3599 3600 if (!dsl_scan_is_running(scn) || dsl_scan_is_paused_scrub(scn)) 3601 return; 3602 3603 /* 3604 * Wait a few txgs after importing to begin scanning so that 3605 * we can get the pool imported quickly. 3606 */ 3607 if (spa->spa_syncing_txg < spa->spa_first_txg + SCAN_IMPORT_WAIT_TXGS) 3608 return; 3609 3610 /* 3611 * zfs_scan_suspend_progress can be set to disable scan progress. 3612 * We don't want to spin the txg_sync thread, so we add a delay 3613 * here to simulate the time spent doing a scan. This is mostly 3614 * useful for testing and debugging. 3615 */ 3616 if (zfs_scan_suspend_progress) { 3617 uint64_t scan_time_ns = gethrtime() - scn->scn_sync_start_time; 3618 int mintime = (scn->scn_phys.scn_func == POOL_SCAN_RESILVER) ? 3619 zfs_resilver_min_time_ms : zfs_scrub_min_time_ms; 3620 3621 while (zfs_scan_suspend_progress && 3622 !txg_sync_waiting(scn->scn_dp) && 3623 !spa_shutting_down(scn->scn_dp->dp_spa) && 3624 NSEC2MSEC(scan_time_ns) < mintime) { 3625 delay(hz); 3626 scan_time_ns = gethrtime() - scn->scn_sync_start_time; 3627 } 3628 return; 3629 } 3630 3631 /* 3632 * It is possible to switch from unsorted to sorted at any time, 3633 * but afterwards the scan will remain sorted unless reloaded from 3634 * a checkpoint after a reboot. 3635 */ 3636 if (!zfs_scan_legacy) { 3637 scn->scn_is_sorted = B_TRUE; 3638 if (scn->scn_last_checkpoint == 0) 3639 scn->scn_last_checkpoint = ddi_get_lbolt(); 3640 } 3641 3642 /* 3643 * For sorted scans, determine what kind of work we will be doing 3644 * this txg based on our memory limitations and whether or not we 3645 * need to perform a checkpoint. 3646 */ 3647 if (scn->scn_is_sorted) { 3648 /* 3649 * If we are over our checkpoint interval, set scn_clearing 3650 * so that we can begin checkpointing immediately. The 3651 * checkpoint allows us to save a consistent bookmark 3652 * representing how much data we have scrubbed so far. 3653 * Otherwise, use the memory limit to determine if we should 3654 * scan for metadata or start issue scrub IOs. We accumulate 3655 * metadata until we hit our hard memory limit at which point 3656 * we issue scrub IOs until we are at our soft memory limit. 3657 */ 3658 if (scn->scn_checkpointing || 3659 ddi_get_lbolt() - scn->scn_last_checkpoint > 3660 SEC_TO_TICK(zfs_scan_checkpoint_intval)) { 3661 if (!scn->scn_checkpointing) 3662 zfs_dbgmsg("begin scan checkpoint for %s", 3663 spa->spa_name); 3664 3665 scn->scn_checkpointing = B_TRUE; 3666 scn->scn_clearing = B_TRUE; 3667 } else { 3668 boolean_t should_clear = dsl_scan_should_clear(scn); 3669 if (should_clear && !scn->scn_clearing) { 3670 zfs_dbgmsg("begin scan clearing for %s", 3671 spa->spa_name); 3672 scn->scn_clearing = B_TRUE; 3673 } else if (!should_clear && scn->scn_clearing) { 3674 zfs_dbgmsg("finish scan clearing for %s", 3675 spa->spa_name); 3676 scn->scn_clearing = B_FALSE; 3677 } 3678 } 3679 } else { 3680 ASSERT0(scn->scn_checkpointing); 3681 ASSERT0(scn->scn_clearing); 3682 } 3683 3684 if (!scn->scn_clearing && scn->scn_done_txg == 0) { 3685 /* Need to scan metadata for more blocks to scrub */ 3686 dsl_scan_phys_t *scnp = &scn->scn_phys; 3687 taskqid_t prefetch_tqid; 3688 3689 /* 3690 * Recalculate the max number of in-flight bytes for pool-wide 3691 * scanning operations (minimum 1MB). Limits for the issuing 3692 * phase are done per top-level vdev and are handled separately. 3693 */ 3694 scn->scn_maxinflight_bytes = MAX(zfs_scan_vdev_limit * 3695 dsl_scan_count_data_disks(spa->spa_root_vdev), 1ULL << 20); 3696 3697 if (scnp->scn_ddt_bookmark.ddb_class <= 3698 scnp->scn_ddt_class_max) { 3699 ASSERT(ZB_IS_ZERO(&scnp->scn_bookmark)); 3700 zfs_dbgmsg("doing scan sync for %s txg %llu; " 3701 "ddt bm=%llu/%llu/%llu/%llx", 3702 spa->spa_name, 3703 (longlong_t)tx->tx_txg, 3704 (longlong_t)scnp->scn_ddt_bookmark.ddb_class, 3705 (longlong_t)scnp->scn_ddt_bookmark.ddb_type, 3706 (longlong_t)scnp->scn_ddt_bookmark.ddb_checksum, 3707 (longlong_t)scnp->scn_ddt_bookmark.ddb_cursor); 3708 } else { 3709 zfs_dbgmsg("doing scan sync for %s txg %llu; " 3710 "bm=%llu/%llu/%llu/%llu", 3711 spa->spa_name, 3712 (longlong_t)tx->tx_txg, 3713 (longlong_t)scnp->scn_bookmark.zb_objset, 3714 (longlong_t)scnp->scn_bookmark.zb_object, 3715 (longlong_t)scnp->scn_bookmark.zb_level, 3716 (longlong_t)scnp->scn_bookmark.zb_blkid); 3717 } 3718 3719 scn->scn_zio_root = zio_root(dp->dp_spa, NULL, 3720 NULL, ZIO_FLAG_CANFAIL); 3721 3722 scn->scn_prefetch_stop = B_FALSE; 3723 prefetch_tqid = taskq_dispatch(dp->dp_sync_taskq, 3724 dsl_scan_prefetch_thread, scn, TQ_SLEEP); 3725 ASSERT(prefetch_tqid != TASKQID_INVALID); 3726 3727 dsl_pool_config_enter(dp, FTAG); 3728 dsl_scan_visit(scn, tx); 3729 dsl_pool_config_exit(dp, FTAG); 3730 3731 mutex_enter(&dp->dp_spa->spa_scrub_lock); 3732 scn->scn_prefetch_stop = B_TRUE; 3733 cv_broadcast(&spa->spa_scrub_io_cv); 3734 mutex_exit(&dp->dp_spa->spa_scrub_lock); 3735 3736 taskq_wait_id(dp->dp_sync_taskq, prefetch_tqid); 3737 (void) zio_wait(scn->scn_zio_root); 3738 scn->scn_zio_root = NULL; 3739 3740 zfs_dbgmsg("scan visited %llu blocks of %s in %llums " 3741 "(%llu os's, %llu holes, %llu < mintxg, " 3742 "%llu in ddt, %llu > maxtxg)", 3743 (longlong_t)scn->scn_visited_this_txg, 3744 spa->spa_name, 3745 (longlong_t)NSEC2MSEC(gethrtime() - 3746 scn->scn_sync_start_time), 3747 (longlong_t)scn->scn_objsets_visited_this_txg, 3748 (longlong_t)scn->scn_holes_this_txg, 3749 (longlong_t)scn->scn_lt_min_this_txg, 3750 (longlong_t)scn->scn_ddt_contained_this_txg, 3751 (longlong_t)scn->scn_gt_max_this_txg); 3752 3753 if (!scn->scn_suspending) { 3754 ASSERT0(avl_numnodes(&scn->scn_queue)); 3755 scn->scn_done_txg = tx->tx_txg + 1; 3756 if (scn->scn_is_sorted) { 3757 scn->scn_checkpointing = B_TRUE; 3758 scn->scn_clearing = B_TRUE; 3759 } 3760 zfs_dbgmsg("scan complete for %s txg %llu", 3761 spa->spa_name, 3762 (longlong_t)tx->tx_txg); 3763 } 3764 } else if (scn->scn_is_sorted && scn->scn_bytes_pending != 0) { 3765 ASSERT(scn->scn_clearing); 3766 3767 /* need to issue scrubbing IOs from per-vdev queues */ 3768 scn->scn_zio_root = zio_root(dp->dp_spa, NULL, 3769 NULL, ZIO_FLAG_CANFAIL); 3770 scan_io_queues_run(scn); 3771 (void) zio_wait(scn->scn_zio_root); 3772 scn->scn_zio_root = NULL; 3773 3774 /* calculate and dprintf the current memory usage */ 3775 (void) dsl_scan_should_clear(scn); 3776 dsl_scan_update_stats(scn); 3777 3778 zfs_dbgmsg("scan issued %llu blocks for %s (%llu segs) " 3779 "in %llums (avg_block_size = %llu, avg_seg_size = %llu)", 3780 (longlong_t)scn->scn_zios_this_txg, 3781 spa->spa_name, 3782 (longlong_t)scn->scn_segs_this_txg, 3783 (longlong_t)NSEC2MSEC(gethrtime() - 3784 scn->scn_sync_start_time), 3785 (longlong_t)scn->scn_avg_zio_size_this_txg, 3786 (longlong_t)scn->scn_avg_seg_size_this_txg); 3787 } else if (scn->scn_done_txg != 0 && scn->scn_done_txg <= tx->tx_txg) { 3788 /* Finished with everything. Mark the scrub as complete */ 3789 zfs_dbgmsg("scan issuing complete txg %llu for %s", 3790 (longlong_t)tx->tx_txg, 3791 spa->spa_name); 3792 ASSERT3U(scn->scn_done_txg, !=, 0); 3793 ASSERT0(spa->spa_scrub_inflight); 3794 ASSERT0(scn->scn_bytes_pending); 3795 dsl_scan_done(scn, B_TRUE, tx); 3796 sync_type = SYNC_MANDATORY; 3797 } 3798 3799 dsl_scan_sync_state(scn, tx, sync_type); 3800 } 3801 3802 static void 3803 count_block(dsl_scan_t *scn, zfs_all_blkstats_t *zab, const blkptr_t *bp) 3804 { 3805 int i; 3806 3807 /* 3808 * Don't count embedded bp's, since we already did the work of 3809 * scanning these when we scanned the containing block. 3810 */ 3811 if (BP_IS_EMBEDDED(bp)) 3812 return; 3813 3814 /* 3815 * Update the spa's stats on how many bytes we have issued. 3816 * Sequential scrubs create a zio for each DVA of the bp. Each 3817 * of these will include all DVAs for repair purposes, but the 3818 * zio code will only try the first one unless there is an issue. 3819 * Therefore, we should only count the first DVA for these IOs. 3820 */ 3821 if (scn->scn_is_sorted) { 3822 atomic_add_64(&scn->scn_dp->dp_spa->spa_scan_pass_issued, 3823 DVA_GET_ASIZE(&bp->blk_dva[0])); 3824 } else { 3825 spa_t *spa = scn->scn_dp->dp_spa; 3826 3827 for (i = 0; i < BP_GET_NDVAS(bp); i++) { 3828 atomic_add_64(&spa->spa_scan_pass_issued, 3829 DVA_GET_ASIZE(&bp->blk_dva[i])); 3830 } 3831 } 3832 3833 /* 3834 * If we resume after a reboot, zab will be NULL; don't record 3835 * incomplete stats in that case. 3836 */ 3837 if (zab == NULL) 3838 return; 3839 3840 mutex_enter(&zab->zab_lock); 3841 3842 for (i = 0; i < 4; i++) { 3843 int l = (i < 2) ? BP_GET_LEVEL(bp) : DN_MAX_LEVELS; 3844 int t = (i & 1) ? BP_GET_TYPE(bp) : DMU_OT_TOTAL; 3845 3846 if (t & DMU_OT_NEWTYPE) 3847 t = DMU_OT_OTHER; 3848 zfs_blkstat_t *zb = &zab->zab_type[l][t]; 3849 int equal; 3850 3851 zb->zb_count++; 3852 zb->zb_asize += BP_GET_ASIZE(bp); 3853 zb->zb_lsize += BP_GET_LSIZE(bp); 3854 zb->zb_psize += BP_GET_PSIZE(bp); 3855 zb->zb_gangs += BP_COUNT_GANG(bp); 3856 3857 switch (BP_GET_NDVAS(bp)) { 3858 case 2: 3859 if (DVA_GET_VDEV(&bp->blk_dva[0]) == 3860 DVA_GET_VDEV(&bp->blk_dva[1])) 3861 zb->zb_ditto_2_of_2_samevdev++; 3862 break; 3863 case 3: 3864 equal = (DVA_GET_VDEV(&bp->blk_dva[0]) == 3865 DVA_GET_VDEV(&bp->blk_dva[1])) + 3866 (DVA_GET_VDEV(&bp->blk_dva[0]) == 3867 DVA_GET_VDEV(&bp->blk_dva[2])) + 3868 (DVA_GET_VDEV(&bp->blk_dva[1]) == 3869 DVA_GET_VDEV(&bp->blk_dva[2])); 3870 if (equal == 1) 3871 zb->zb_ditto_2_of_3_samevdev++; 3872 else if (equal == 3) 3873 zb->zb_ditto_3_of_3_samevdev++; 3874 break; 3875 } 3876 } 3877 3878 mutex_exit(&zab->zab_lock); 3879 } 3880 3881 static void 3882 scan_io_queue_insert_impl(dsl_scan_io_queue_t *queue, scan_io_t *sio) 3883 { 3884 avl_index_t idx; 3885 int64_t asize = SIO_GET_ASIZE(sio); 3886 dsl_scan_t *scn = queue->q_scn; 3887 3888 ASSERT(MUTEX_HELD(&queue->q_vd->vdev_scan_io_queue_lock)); 3889 3890 if (avl_find(&queue->q_sios_by_addr, sio, &idx) != NULL) { 3891 /* block is already scheduled for reading */ 3892 atomic_add_64(&scn->scn_bytes_pending, -asize); 3893 sio_free(sio); 3894 return; 3895 } 3896 avl_insert(&queue->q_sios_by_addr, sio, idx); 3897 queue->q_sio_memused += SIO_GET_MUSED(sio); 3898 range_tree_add(queue->q_exts_by_addr, SIO_GET_OFFSET(sio), asize); 3899 } 3900 3901 /* 3902 * Given all the info we got from our metadata scanning process, we 3903 * construct a scan_io_t and insert it into the scan sorting queue. The 3904 * I/O must already be suitable for us to process. This is controlled 3905 * by dsl_scan_enqueue(). 3906 */ 3907 static void 3908 scan_io_queue_insert(dsl_scan_io_queue_t *queue, const blkptr_t *bp, int dva_i, 3909 int zio_flags, const zbookmark_phys_t *zb) 3910 { 3911 dsl_scan_t *scn = queue->q_scn; 3912 scan_io_t *sio = sio_alloc(BP_GET_NDVAS(bp)); 3913 3914 ASSERT0(BP_IS_GANG(bp)); 3915 ASSERT(MUTEX_HELD(&queue->q_vd->vdev_scan_io_queue_lock)); 3916 3917 bp2sio(bp, sio, dva_i); 3918 sio->sio_flags = zio_flags; 3919 sio->sio_zb = *zb; 3920 3921 /* 3922 * Increment the bytes pending counter now so that we can't 3923 * get an integer underflow in case the worker processes the 3924 * zio before we get to incrementing this counter. 3925 */ 3926 atomic_add_64(&scn->scn_bytes_pending, SIO_GET_ASIZE(sio)); 3927 3928 scan_io_queue_insert_impl(queue, sio); 3929 } 3930 3931 /* 3932 * Given a set of I/O parameters as discovered by the metadata traversal 3933 * process, attempts to place the I/O into the sorted queues (if allowed), 3934 * or immediately executes the I/O. 3935 */ 3936 static void 3937 dsl_scan_enqueue(dsl_pool_t *dp, const blkptr_t *bp, int zio_flags, 3938 const zbookmark_phys_t *zb) 3939 { 3940 spa_t *spa = dp->dp_spa; 3941 3942 ASSERT(!BP_IS_EMBEDDED(bp)); 3943 3944 /* 3945 * Gang blocks are hard to issue sequentially, so we just issue them 3946 * here immediately instead of queuing them. 3947 */ 3948 if (!dp->dp_scan->scn_is_sorted || BP_IS_GANG(bp)) { 3949 scan_exec_io(dp, bp, zio_flags, zb, NULL); 3950 return; 3951 } 3952 3953 for (int i = 0; i < BP_GET_NDVAS(bp); i++) { 3954 dva_t dva; 3955 vdev_t *vdev; 3956 3957 dva = bp->blk_dva[i]; 3958 vdev = vdev_lookup_top(spa, DVA_GET_VDEV(&dva)); 3959 ASSERT(vdev != NULL); 3960 3961 mutex_enter(&vdev->vdev_scan_io_queue_lock); 3962 if (vdev->vdev_scan_io_queue == NULL) 3963 vdev->vdev_scan_io_queue = scan_io_queue_create(vdev); 3964 ASSERT(dp->dp_scan != NULL); 3965 scan_io_queue_insert(vdev->vdev_scan_io_queue, bp, 3966 i, zio_flags, zb); 3967 mutex_exit(&vdev->vdev_scan_io_queue_lock); 3968 } 3969 } 3970 3971 static int 3972 dsl_scan_scrub_cb(dsl_pool_t *dp, 3973 const blkptr_t *bp, const zbookmark_phys_t *zb) 3974 { 3975 dsl_scan_t *scn = dp->dp_scan; 3976 spa_t *spa = dp->dp_spa; 3977 uint64_t phys_birth = BP_PHYSICAL_BIRTH(bp); 3978 size_t psize = BP_GET_PSIZE(bp); 3979 boolean_t needs_io = B_FALSE; 3980 int zio_flags = ZIO_FLAG_SCAN_THREAD | ZIO_FLAG_RAW | ZIO_FLAG_CANFAIL; 3981 3982 3983 if (phys_birth <= scn->scn_phys.scn_min_txg || 3984 phys_birth >= scn->scn_phys.scn_max_txg) { 3985 count_block(scn, dp->dp_blkstats, bp); 3986 return (0); 3987 } 3988 3989 /* Embedded BP's have phys_birth==0, so we reject them above. */ 3990 ASSERT(!BP_IS_EMBEDDED(bp)); 3991 3992 ASSERT(DSL_SCAN_IS_SCRUB_RESILVER(scn)); 3993 if (scn->scn_phys.scn_func == POOL_SCAN_SCRUB) { 3994 zio_flags |= ZIO_FLAG_SCRUB; 3995 needs_io = B_TRUE; 3996 } else { 3997 ASSERT3U(scn->scn_phys.scn_func, ==, POOL_SCAN_RESILVER); 3998 zio_flags |= ZIO_FLAG_RESILVER; 3999 needs_io = B_FALSE; 4000 } 4001 4002 /* If it's an intent log block, failure is expected. */ 4003 if (zb->zb_level == ZB_ZIL_LEVEL) 4004 zio_flags |= ZIO_FLAG_SPECULATIVE; 4005 4006 for (int d = 0; d < BP_GET_NDVAS(bp); d++) { 4007 const dva_t *dva = &bp->blk_dva[d]; 4008 4009 /* 4010 * Keep track of how much data we've examined so that 4011 * zpool(8) status can make useful progress reports. 4012 */ 4013 scn->scn_phys.scn_examined += DVA_GET_ASIZE(dva); 4014 spa->spa_scan_pass_exam += DVA_GET_ASIZE(dva); 4015 4016 /* if it's a resilver, this may not be in the target range */ 4017 if (!needs_io) 4018 needs_io = dsl_scan_need_resilver(spa, dva, psize, 4019 phys_birth); 4020 } 4021 4022 if (needs_io && !zfs_no_scrub_io) { 4023 dsl_scan_enqueue(dp, bp, zio_flags, zb); 4024 } else { 4025 count_block(scn, dp->dp_blkstats, bp); 4026 } 4027 4028 /* do not relocate this block */ 4029 return (0); 4030 } 4031 4032 static void 4033 dsl_scan_scrub_done(zio_t *zio) 4034 { 4035 spa_t *spa = zio->io_spa; 4036 blkptr_t *bp = zio->io_bp; 4037 dsl_scan_io_queue_t *queue = zio->io_private; 4038 4039 abd_free(zio->io_abd); 4040 4041 if (queue == NULL) { 4042 mutex_enter(&spa->spa_scrub_lock); 4043 ASSERT3U(spa->spa_scrub_inflight, >=, BP_GET_PSIZE(bp)); 4044 spa->spa_scrub_inflight -= BP_GET_PSIZE(bp); 4045 cv_broadcast(&spa->spa_scrub_io_cv); 4046 mutex_exit(&spa->spa_scrub_lock); 4047 } else { 4048 mutex_enter(&queue->q_vd->vdev_scan_io_queue_lock); 4049 ASSERT3U(queue->q_inflight_bytes, >=, BP_GET_PSIZE(bp)); 4050 queue->q_inflight_bytes -= BP_GET_PSIZE(bp); 4051 cv_broadcast(&queue->q_zio_cv); 4052 mutex_exit(&queue->q_vd->vdev_scan_io_queue_lock); 4053 } 4054 4055 if (zio->io_error && (zio->io_error != ECKSUM || 4056 !(zio->io_flags & ZIO_FLAG_SPECULATIVE))) { 4057 atomic_inc_64(&spa->spa_dsl_pool->dp_scan->scn_phys.scn_errors); 4058 } 4059 } 4060 4061 /* 4062 * Given a scanning zio's information, executes the zio. The zio need 4063 * not necessarily be only sortable, this function simply executes the 4064 * zio, no matter what it is. The optional queue argument allows the 4065 * caller to specify that they want per top level vdev IO rate limiting 4066 * instead of the legacy global limiting. 4067 */ 4068 static void 4069 scan_exec_io(dsl_pool_t *dp, const blkptr_t *bp, int zio_flags, 4070 const zbookmark_phys_t *zb, dsl_scan_io_queue_t *queue) 4071 { 4072 spa_t *spa = dp->dp_spa; 4073 dsl_scan_t *scn = dp->dp_scan; 4074 size_t size = BP_GET_PSIZE(bp); 4075 abd_t *data = abd_alloc_for_io(size, B_FALSE); 4076 4077 if (queue == NULL) { 4078 ASSERT3U(scn->scn_maxinflight_bytes, >, 0); 4079 mutex_enter(&spa->spa_scrub_lock); 4080 while (spa->spa_scrub_inflight >= scn->scn_maxinflight_bytes) 4081 cv_wait(&spa->spa_scrub_io_cv, &spa->spa_scrub_lock); 4082 spa->spa_scrub_inflight += BP_GET_PSIZE(bp); 4083 mutex_exit(&spa->spa_scrub_lock); 4084 } else { 4085 kmutex_t *q_lock = &queue->q_vd->vdev_scan_io_queue_lock; 4086 4087 ASSERT3U(queue->q_maxinflight_bytes, >, 0); 4088 mutex_enter(q_lock); 4089 while (queue->q_inflight_bytes >= queue->q_maxinflight_bytes) 4090 cv_wait(&queue->q_zio_cv, q_lock); 4091 queue->q_inflight_bytes += BP_GET_PSIZE(bp); 4092 mutex_exit(q_lock); 4093 } 4094 4095 count_block(scn, dp->dp_blkstats, bp); 4096 zio_nowait(zio_read(scn->scn_zio_root, spa, bp, data, size, 4097 dsl_scan_scrub_done, queue, ZIO_PRIORITY_SCRUB, zio_flags, zb)); 4098 } 4099 4100 /* 4101 * This is the primary extent sorting algorithm. We balance two parameters: 4102 * 1) how many bytes of I/O are in an extent 4103 * 2) how well the extent is filled with I/O (as a fraction of its total size) 4104 * Since we allow extents to have gaps between their constituent I/Os, it's 4105 * possible to have a fairly large extent that contains the same amount of 4106 * I/O bytes than a much smaller extent, which just packs the I/O more tightly. 4107 * The algorithm sorts based on a score calculated from the extent's size, 4108 * the relative fill volume (in %) and a "fill weight" parameter that controls 4109 * the split between whether we prefer larger extents or more well populated 4110 * extents: 4111 * 4112 * SCORE = FILL_IN_BYTES + (FILL_IN_PERCENT * FILL_IN_BYTES * FILL_WEIGHT) 4113 * 4114 * Example: 4115 * 1) assume extsz = 64 MiB 4116 * 2) assume fill = 32 MiB (extent is half full) 4117 * 3) assume fill_weight = 3 4118 * 4) SCORE = 32M + (((32M * 100) / 64M) * 3 * 32M) / 100 4119 * SCORE = 32M + (50 * 3 * 32M) / 100 4120 * SCORE = 32M + (4800M / 100) 4121 * SCORE = 32M + 48M 4122 * ^ ^ 4123 * | +--- final total relative fill-based score 4124 * +--------- final total fill-based score 4125 * SCORE = 80M 4126 * 4127 * As can be seen, at fill_ratio=3, the algorithm is slightly biased towards 4128 * extents that are more completely filled (in a 3:2 ratio) vs just larger. 4129 * Note that as an optimization, we replace multiplication and division by 4130 * 100 with bitshifting by 7 (which effectively multiplies and divides by 128). 4131 */ 4132 static int 4133 ext_size_compare(const void *x, const void *y) 4134 { 4135 const range_seg_gap_t *rsa = x, *rsb = y; 4136 4137 uint64_t sa = rsa->rs_end - rsa->rs_start; 4138 uint64_t sb = rsb->rs_end - rsb->rs_start; 4139 uint64_t score_a, score_b; 4140 4141 score_a = rsa->rs_fill + ((((rsa->rs_fill << 7) / sa) * 4142 fill_weight * rsa->rs_fill) >> 7); 4143 score_b = rsb->rs_fill + ((((rsb->rs_fill << 7) / sb) * 4144 fill_weight * rsb->rs_fill) >> 7); 4145 4146 if (score_a > score_b) 4147 return (-1); 4148 if (score_a == score_b) { 4149 if (rsa->rs_start < rsb->rs_start) 4150 return (-1); 4151 if (rsa->rs_start == rsb->rs_start) 4152 return (0); 4153 return (1); 4154 } 4155 return (1); 4156 } 4157 4158 /* 4159 * Comparator for the q_sios_by_addr tree. Sorting is simply performed 4160 * based on LBA-order (from lowest to highest). 4161 */ 4162 static int 4163 sio_addr_compare(const void *x, const void *y) 4164 { 4165 const scan_io_t *a = x, *b = y; 4166 4167 return (TREE_CMP(SIO_GET_OFFSET(a), SIO_GET_OFFSET(b))); 4168 } 4169 4170 /* IO queues are created on demand when they are needed. */ 4171 static dsl_scan_io_queue_t * 4172 scan_io_queue_create(vdev_t *vd) 4173 { 4174 dsl_scan_t *scn = vd->vdev_spa->spa_dsl_pool->dp_scan; 4175 dsl_scan_io_queue_t *q = kmem_zalloc(sizeof (*q), KM_SLEEP); 4176 4177 q->q_scn = scn; 4178 q->q_vd = vd; 4179 q->q_sio_memused = 0; 4180 cv_init(&q->q_zio_cv, NULL, CV_DEFAULT, NULL); 4181 q->q_exts_by_addr = range_tree_create_impl(&rt_btree_ops, RANGE_SEG_GAP, 4182 &q->q_exts_by_size, 0, 0, ext_size_compare, zfs_scan_max_ext_gap); 4183 avl_create(&q->q_sios_by_addr, sio_addr_compare, 4184 sizeof (scan_io_t), offsetof(scan_io_t, sio_nodes.sio_addr_node)); 4185 4186 return (q); 4187 } 4188 4189 /* 4190 * Destroys a scan queue and all segments and scan_io_t's contained in it. 4191 * No further execution of I/O occurs, anything pending in the queue is 4192 * simply freed without being executed. 4193 */ 4194 void 4195 dsl_scan_io_queue_destroy(dsl_scan_io_queue_t *queue) 4196 { 4197 dsl_scan_t *scn = queue->q_scn; 4198 scan_io_t *sio; 4199 void *cookie = NULL; 4200 int64_t bytes_dequeued = 0; 4201 4202 ASSERT(MUTEX_HELD(&queue->q_vd->vdev_scan_io_queue_lock)); 4203 4204 while ((sio = avl_destroy_nodes(&queue->q_sios_by_addr, &cookie)) != 4205 NULL) { 4206 ASSERT(range_tree_contains(queue->q_exts_by_addr, 4207 SIO_GET_OFFSET(sio), SIO_GET_ASIZE(sio))); 4208 bytes_dequeued += SIO_GET_ASIZE(sio); 4209 queue->q_sio_memused -= SIO_GET_MUSED(sio); 4210 sio_free(sio); 4211 } 4212 4213 ASSERT0(queue->q_sio_memused); 4214 atomic_add_64(&scn->scn_bytes_pending, -bytes_dequeued); 4215 range_tree_vacate(queue->q_exts_by_addr, NULL, queue); 4216 range_tree_destroy(queue->q_exts_by_addr); 4217 avl_destroy(&queue->q_sios_by_addr); 4218 cv_destroy(&queue->q_zio_cv); 4219 4220 kmem_free(queue, sizeof (*queue)); 4221 } 4222 4223 /* 4224 * Properly transfers a dsl_scan_queue_t from `svd' to `tvd'. This is 4225 * called on behalf of vdev_top_transfer when creating or destroying 4226 * a mirror vdev due to zpool attach/detach. 4227 */ 4228 void 4229 dsl_scan_io_queue_vdev_xfer(vdev_t *svd, vdev_t *tvd) 4230 { 4231 mutex_enter(&svd->vdev_scan_io_queue_lock); 4232 mutex_enter(&tvd->vdev_scan_io_queue_lock); 4233 4234 VERIFY3P(tvd->vdev_scan_io_queue, ==, NULL); 4235 tvd->vdev_scan_io_queue = svd->vdev_scan_io_queue; 4236 svd->vdev_scan_io_queue = NULL; 4237 if (tvd->vdev_scan_io_queue != NULL) 4238 tvd->vdev_scan_io_queue->q_vd = tvd; 4239 4240 mutex_exit(&tvd->vdev_scan_io_queue_lock); 4241 mutex_exit(&svd->vdev_scan_io_queue_lock); 4242 } 4243 4244 static void 4245 scan_io_queues_destroy(dsl_scan_t *scn) 4246 { 4247 vdev_t *rvd = scn->scn_dp->dp_spa->spa_root_vdev; 4248 4249 for (uint64_t i = 0; i < rvd->vdev_children; i++) { 4250 vdev_t *tvd = rvd->vdev_child[i]; 4251 4252 mutex_enter(&tvd->vdev_scan_io_queue_lock); 4253 if (tvd->vdev_scan_io_queue != NULL) 4254 dsl_scan_io_queue_destroy(tvd->vdev_scan_io_queue); 4255 tvd->vdev_scan_io_queue = NULL; 4256 mutex_exit(&tvd->vdev_scan_io_queue_lock); 4257 } 4258 } 4259 4260 static void 4261 dsl_scan_freed_dva(spa_t *spa, const blkptr_t *bp, int dva_i) 4262 { 4263 dsl_pool_t *dp = spa->spa_dsl_pool; 4264 dsl_scan_t *scn = dp->dp_scan; 4265 vdev_t *vdev; 4266 kmutex_t *q_lock; 4267 dsl_scan_io_queue_t *queue; 4268 scan_io_t *srch_sio, *sio; 4269 avl_index_t idx; 4270 uint64_t start, size; 4271 4272 vdev = vdev_lookup_top(spa, DVA_GET_VDEV(&bp->blk_dva[dva_i])); 4273 ASSERT(vdev != NULL); 4274 q_lock = &vdev->vdev_scan_io_queue_lock; 4275 queue = vdev->vdev_scan_io_queue; 4276 4277 mutex_enter(q_lock); 4278 if (queue == NULL) { 4279 mutex_exit(q_lock); 4280 return; 4281 } 4282 4283 srch_sio = sio_alloc(BP_GET_NDVAS(bp)); 4284 bp2sio(bp, srch_sio, dva_i); 4285 start = SIO_GET_OFFSET(srch_sio); 4286 size = SIO_GET_ASIZE(srch_sio); 4287 4288 /* 4289 * We can find the zio in two states: 4290 * 1) Cold, just sitting in the queue of zio's to be issued at 4291 * some point in the future. In this case, all we do is 4292 * remove the zio from the q_sios_by_addr tree, decrement 4293 * its data volume from the containing range_seg_t and 4294 * resort the q_exts_by_size tree to reflect that the 4295 * range_seg_t has lost some of its 'fill'. We don't shorten 4296 * the range_seg_t - this is usually rare enough not to be 4297 * worth the extra hassle of trying keep track of precise 4298 * extent boundaries. 4299 * 2) Hot, where the zio is currently in-flight in 4300 * dsl_scan_issue_ios. In this case, we can't simply 4301 * reach in and stop the in-flight zio's, so we instead 4302 * block the caller. Eventually, dsl_scan_issue_ios will 4303 * be done with issuing the zio's it gathered and will 4304 * signal us. 4305 */ 4306 sio = avl_find(&queue->q_sios_by_addr, srch_sio, &idx); 4307 sio_free(srch_sio); 4308 4309 if (sio != NULL) { 4310 int64_t asize = SIO_GET_ASIZE(sio); 4311 blkptr_t tmpbp; 4312 4313 /* Got it while it was cold in the queue */ 4314 ASSERT3U(start, ==, SIO_GET_OFFSET(sio)); 4315 ASSERT3U(size, ==, asize); 4316 avl_remove(&queue->q_sios_by_addr, sio); 4317 queue->q_sio_memused -= SIO_GET_MUSED(sio); 4318 4319 ASSERT(range_tree_contains(queue->q_exts_by_addr, start, size)); 4320 range_tree_remove_fill(queue->q_exts_by_addr, start, size); 4321 4322 /* 4323 * We only update scn_bytes_pending in the cold path, 4324 * otherwise it will already have been accounted for as 4325 * part of the zio's execution. 4326 */ 4327 atomic_add_64(&scn->scn_bytes_pending, -asize); 4328 4329 /* count the block as though we issued it */ 4330 sio2bp(sio, &tmpbp); 4331 count_block(scn, dp->dp_blkstats, &tmpbp); 4332 4333 sio_free(sio); 4334 } 4335 mutex_exit(q_lock); 4336 } 4337 4338 /* 4339 * Callback invoked when a zio_free() zio is executing. This needs to be 4340 * intercepted to prevent the zio from deallocating a particular portion 4341 * of disk space and it then getting reallocated and written to, while we 4342 * still have it queued up for processing. 4343 */ 4344 void 4345 dsl_scan_freed(spa_t *spa, const blkptr_t *bp) 4346 { 4347 dsl_pool_t *dp = spa->spa_dsl_pool; 4348 dsl_scan_t *scn = dp->dp_scan; 4349 4350 ASSERT(!BP_IS_EMBEDDED(bp)); 4351 ASSERT(scn != NULL); 4352 if (!dsl_scan_is_running(scn)) 4353 return; 4354 4355 for (int i = 0; i < BP_GET_NDVAS(bp); i++) 4356 dsl_scan_freed_dva(spa, bp, i); 4357 } 4358 4359 /* 4360 * Check if a vdev needs resilvering (non-empty DTL), if so, and resilver has 4361 * not started, start it. Otherwise, only restart if max txg in DTL range is 4362 * greater than the max txg in the current scan. If the DTL max is less than 4363 * the scan max, then the vdev has not missed any new data since the resilver 4364 * started, so a restart is not needed. 4365 */ 4366 void 4367 dsl_scan_assess_vdev(dsl_pool_t *dp, vdev_t *vd) 4368 { 4369 uint64_t min, max; 4370 4371 if (!vdev_resilver_needed(vd, &min, &max)) 4372 return; 4373 4374 if (!dsl_scan_resilvering(dp)) { 4375 spa_async_request(dp->dp_spa, SPA_ASYNC_RESILVER); 4376 return; 4377 } 4378 4379 if (max <= dp->dp_scan->scn_phys.scn_max_txg) 4380 return; 4381 4382 /* restart is needed, check if it can be deferred */ 4383 if (spa_feature_is_enabled(dp->dp_spa, SPA_FEATURE_RESILVER_DEFER)) 4384 vdev_defer_resilver(vd); 4385 else 4386 spa_async_request(dp->dp_spa, SPA_ASYNC_RESILVER); 4387 } 4388 4389 ZFS_MODULE_PARAM(zfs, zfs_, scan_vdev_limit, ULONG, ZMOD_RW, 4390 "Max bytes in flight per leaf vdev for scrubs and resilvers"); 4391 4392 ZFS_MODULE_PARAM(zfs, zfs_, scrub_min_time_ms, INT, ZMOD_RW, 4393 "Min millisecs to scrub per txg"); 4394 4395 ZFS_MODULE_PARAM(zfs, zfs_, obsolete_min_time_ms, INT, ZMOD_RW, 4396 "Min millisecs to obsolete per txg"); 4397 4398 ZFS_MODULE_PARAM(zfs, zfs_, free_min_time_ms, INT, ZMOD_RW, 4399 "Min millisecs to free per txg"); 4400 4401 ZFS_MODULE_PARAM(zfs, zfs_, resilver_min_time_ms, INT, ZMOD_RW, 4402 "Min millisecs to resilver per txg"); 4403 4404 ZFS_MODULE_PARAM(zfs, zfs_, scan_suspend_progress, INT, ZMOD_RW, 4405 "Set to prevent scans from progressing"); 4406 4407 ZFS_MODULE_PARAM(zfs, zfs_, no_scrub_io, INT, ZMOD_RW, 4408 "Set to disable scrub I/O"); 4409 4410 ZFS_MODULE_PARAM(zfs, zfs_, no_scrub_prefetch, INT, ZMOD_RW, 4411 "Set to disable scrub prefetching"); 4412 4413 ZFS_MODULE_PARAM(zfs, zfs_, async_block_max_blocks, ULONG, ZMOD_RW, 4414 "Max number of blocks freed in one txg"); 4415 4416 ZFS_MODULE_PARAM(zfs, zfs_, max_async_dedup_frees, ULONG, ZMOD_RW, 4417 "Max number of dedup blocks freed in one txg"); 4418 4419 ZFS_MODULE_PARAM(zfs, zfs_, free_bpobj_enabled, INT, ZMOD_RW, 4420 "Enable processing of the free_bpobj"); 4421 4422 ZFS_MODULE_PARAM(zfs, zfs_, scan_mem_lim_fact, INT, ZMOD_RW, 4423 "Fraction of RAM for scan hard limit"); 4424 4425 ZFS_MODULE_PARAM(zfs, zfs_, scan_issue_strategy, INT, ZMOD_RW, 4426 "IO issuing strategy during scrubbing. 0 = default, 1 = LBA, 2 = size"); 4427 4428 ZFS_MODULE_PARAM(zfs, zfs_, scan_legacy, INT, ZMOD_RW, 4429 "Scrub using legacy non-sequential method"); 4430 4431 ZFS_MODULE_PARAM(zfs, zfs_, scan_checkpoint_intval, INT, ZMOD_RW, 4432 "Scan progress on-disk checkpointing interval"); 4433 4434 ZFS_MODULE_PARAM(zfs, zfs_, scan_max_ext_gap, ULONG, ZMOD_RW, 4435 "Max gap in bytes between sequential scrub / resilver I/Os"); 4436 4437 ZFS_MODULE_PARAM(zfs, zfs_, scan_mem_lim_soft_fact, INT, ZMOD_RW, 4438 "Fraction of hard limit used as soft limit"); 4439 4440 ZFS_MODULE_PARAM(zfs, zfs_, scan_strict_mem_lim, INT, ZMOD_RW, 4441 "Tunable to attempt to reduce lock contention"); 4442 4443 ZFS_MODULE_PARAM(zfs, zfs_, scan_fill_weight, INT, ZMOD_RW, 4444 "Tunable to adjust bias towards more filled segments during scans"); 4445 4446 ZFS_MODULE_PARAM(zfs, zfs_, resilver_disable_defer, INT, ZMOD_RW, 4447 "Process all resilvers immediately"); 4448