1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21 /* 22 * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved. 23 * Copyright (c) 2011, 2017 by Delphix. All rights reserved. 24 * Copyright (c) 2013 Steven Hartland. All rights reserved. 25 * Copyright (c) 2014 Spectra Logic Corporation, All rights reserved. 26 * Copyright (c) 2014 Integros [integros.com] 27 * Copyright 2016 Nexenta Systems, Inc. All rights reserved. 28 */ 29 30 #include <sys/dsl_pool.h> 31 #include <sys/dsl_dataset.h> 32 #include <sys/dsl_prop.h> 33 #include <sys/dsl_dir.h> 34 #include <sys/dsl_synctask.h> 35 #include <sys/dsl_scan.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/dsl_deadlist.h> 47 #include <sys/bptree.h> 48 #include <sys/zfeature.h> 49 #include <sys/zil_impl.h> 50 #include <sys/dsl_userhold.h> 51 52 /* 53 * ZFS Write Throttle 54 * ------------------ 55 * 56 * ZFS must limit the rate of incoming writes to the rate at which it is able 57 * to sync data modifications to the backend storage. Throttling by too much 58 * creates an artificial limit; throttling by too little can only be sustained 59 * for short periods and would lead to highly lumpy performance. On a per-pool 60 * basis, ZFS tracks the amount of modified (dirty) data. As operations change 61 * data, the amount of dirty data increases; as ZFS syncs out data, the amount 62 * of dirty data decreases. When the amount of dirty data exceeds a 63 * predetermined threshold further modifications are blocked until the amount 64 * of dirty data decreases (as data is synced out). 65 * 66 * The limit on dirty data is tunable, and should be adjusted according to 67 * both the IO capacity and available memory of the system. The larger the 68 * window, the more ZFS is able to aggregate and amortize metadata (and data) 69 * changes. However, memory is a limited resource, and allowing for more dirty 70 * data comes at the cost of keeping other useful data in memory (for example 71 * ZFS data cached by the ARC). 72 * 73 * Implementation 74 * 75 * As buffers are modified dsl_pool_willuse_space() increments both the per- 76 * txg (dp_dirty_pertxg[]) and poolwide (dp_dirty_total) accounting of 77 * dirty space used; dsl_pool_dirty_space() decrements those values as data 78 * is synced out from dsl_pool_sync(). While only the poolwide value is 79 * relevant, the per-txg value is useful for debugging. The tunable 80 * zfs_dirty_data_max determines the dirty space limit. Once that value is 81 * exceeded, new writes are halted until space frees up. 82 * 83 * The zfs_dirty_data_sync tunable dictates the threshold at which we 84 * ensure that there is a txg syncing (see the comment in txg.c for a full 85 * description of transaction group stages). 86 * 87 * The IO scheduler uses both the dirty space limit and current amount of 88 * dirty data as inputs. Those values affect the number of concurrent IOs ZFS 89 * issues. See the comment in vdev_queue.c for details of the IO scheduler. 90 * 91 * The delay is also calculated based on the amount of dirty data. See the 92 * comment above dmu_tx_delay() for details. 93 */ 94 95 /* 96 * zfs_dirty_data_max will be set to zfs_dirty_data_max_percent% of all memory, 97 * capped at zfs_dirty_data_max_max. It can also be overridden in /etc/system. 98 */ 99 uint64_t zfs_dirty_data_max; 100 uint64_t zfs_dirty_data_max_max = 4ULL * 1024 * 1024 * 1024; 101 int zfs_dirty_data_max_percent = 10; 102 103 /* 104 * If there is at least this much dirty data, push out a txg. 105 */ 106 uint64_t zfs_dirty_data_sync = 64 * 1024 * 1024; 107 108 /* 109 * Once there is this amount of dirty data, the dmu_tx_delay() will kick in 110 * and delay each transaction. 111 * This value should be >= zfs_vdev_async_write_active_max_dirty_percent. 112 */ 113 int zfs_delay_min_dirty_percent = 60; 114 115 /* 116 * This controls how quickly the delay approaches infinity. 117 * Larger values cause it to delay more for a given amount of dirty data. 118 * Therefore larger values will cause there to be less dirty data for a 119 * given throughput. 120 * 121 * For the smoothest delay, this value should be about 1 billion divided 122 * by the maximum number of operations per second. This will smoothly 123 * handle between 10x and 1/10th this number. 124 * 125 * Note: zfs_delay_scale * zfs_dirty_data_max must be < 2^64, due to the 126 * multiply in dmu_tx_delay(). 127 */ 128 uint64_t zfs_delay_scale = 1000 * 1000 * 1000 / 2000; 129 130 /* 131 * This determines the number of threads used by the dp_sync_taskq. 132 */ 133 int zfs_sync_taskq_batch_pct = 75; 134 135 /* 136 * These tunables determine the behavior of how zil_itxg_clean() is 137 * called via zil_clean() in the context of spa_sync(). When an itxg 138 * list needs to be cleaned, TQ_NOSLEEP will be used when dispatching. 139 * If the dispatch fails, the call to zil_itxg_clean() will occur 140 * synchronously in the context of spa_sync(), which can negatively 141 * impact the performance of spa_sync() (e.g. in the case of the itxg 142 * list having a large number of itxs that needs to be cleaned). 143 * 144 * Thus, these tunables can be used to manipulate the behavior of the 145 * taskq used by zil_clean(); they determine the number of taskq entries 146 * that are pre-populated when the taskq is first created (via the 147 * "zfs_zil_clean_taskq_minalloc" tunable) and the maximum number of 148 * taskq entries that are cached after an on-demand allocation (via the 149 * "zfs_zil_clean_taskq_maxalloc"). 150 * 151 * The idea being, we want to try reasonably hard to ensure there will 152 * already be a taskq entry pre-allocated by the time that it is needed 153 * by zil_clean(). This way, we can avoid the possibility of an 154 * on-demand allocation of a new taskq entry from failing, which would 155 * result in zil_itxg_clean() being called synchronously from zil_clean() 156 * (which can adversely affect performance of spa_sync()). 157 * 158 * Additionally, the number of threads used by the taskq can be 159 * configured via the "zfs_zil_clean_taskq_nthr_pct" tunable. 160 */ 161 int zfs_zil_clean_taskq_nthr_pct = 100; 162 int zfs_zil_clean_taskq_minalloc = 1024; 163 int zfs_zil_clean_taskq_maxalloc = 1024 * 1024; 164 165 int 166 dsl_pool_open_special_dir(dsl_pool_t *dp, const char *name, dsl_dir_t **ddp) 167 { 168 uint64_t obj; 169 int err; 170 171 err = zap_lookup(dp->dp_meta_objset, 172 dsl_dir_phys(dp->dp_root_dir)->dd_child_dir_zapobj, 173 name, sizeof (obj), 1, &obj); 174 if (err) 175 return (err); 176 177 return (dsl_dir_hold_obj(dp, obj, name, dp, ddp)); 178 } 179 180 static dsl_pool_t * 181 dsl_pool_open_impl(spa_t *spa, uint64_t txg) 182 { 183 dsl_pool_t *dp; 184 blkptr_t *bp = spa_get_rootblkptr(spa); 185 186 dp = kmem_zalloc(sizeof (dsl_pool_t), KM_SLEEP); 187 dp->dp_spa = spa; 188 dp->dp_meta_rootbp = *bp; 189 rrw_init(&dp->dp_config_rwlock, B_TRUE); 190 txg_init(dp, txg); 191 192 txg_list_create(&dp->dp_dirty_datasets, spa, 193 offsetof(dsl_dataset_t, ds_dirty_link)); 194 txg_list_create(&dp->dp_dirty_zilogs, spa, 195 offsetof(zilog_t, zl_dirty_link)); 196 txg_list_create(&dp->dp_dirty_dirs, spa, 197 offsetof(dsl_dir_t, dd_dirty_link)); 198 txg_list_create(&dp->dp_sync_tasks, spa, 199 offsetof(dsl_sync_task_t, dst_node)); 200 201 dp->dp_sync_taskq = taskq_create("dp_sync_taskq", 202 zfs_sync_taskq_batch_pct, minclsyspri, 1, INT_MAX, 203 TASKQ_THREADS_CPU_PCT); 204 205 dp->dp_zil_clean_taskq = taskq_create("dp_zil_clean_taskq", 206 zfs_zil_clean_taskq_nthr_pct, minclsyspri, 207 zfs_zil_clean_taskq_minalloc, 208 zfs_zil_clean_taskq_maxalloc, 209 TASKQ_PREPOPULATE | TASKQ_THREADS_CPU_PCT); 210 211 mutex_init(&dp->dp_lock, NULL, MUTEX_DEFAULT, NULL); 212 cv_init(&dp->dp_spaceavail_cv, NULL, CV_DEFAULT, NULL); 213 214 dp->dp_vnrele_taskq = taskq_create("zfs_vn_rele_taskq", 1, minclsyspri, 215 1, 4, 0); 216 217 return (dp); 218 } 219 220 int 221 dsl_pool_init(spa_t *spa, uint64_t txg, dsl_pool_t **dpp) 222 { 223 int err; 224 dsl_pool_t *dp = dsl_pool_open_impl(spa, txg); 225 226 err = dmu_objset_open_impl(spa, NULL, &dp->dp_meta_rootbp, 227 &dp->dp_meta_objset); 228 if (err != 0) 229 dsl_pool_close(dp); 230 else 231 *dpp = dp; 232 233 return (err); 234 } 235 236 int 237 dsl_pool_open(dsl_pool_t *dp) 238 { 239 int err; 240 dsl_dir_t *dd; 241 dsl_dataset_t *ds; 242 uint64_t obj; 243 244 rrw_enter(&dp->dp_config_rwlock, RW_WRITER, FTAG); 245 err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT, 246 DMU_POOL_ROOT_DATASET, sizeof (uint64_t), 1, 247 &dp->dp_root_dir_obj); 248 if (err) 249 goto out; 250 251 err = dsl_dir_hold_obj(dp, dp->dp_root_dir_obj, 252 NULL, dp, &dp->dp_root_dir); 253 if (err) 254 goto out; 255 256 err = dsl_pool_open_special_dir(dp, MOS_DIR_NAME, &dp->dp_mos_dir); 257 if (err) 258 goto out; 259 260 if (spa_version(dp->dp_spa) >= SPA_VERSION_ORIGIN) { 261 err = dsl_pool_open_special_dir(dp, ORIGIN_DIR_NAME, &dd); 262 if (err) 263 goto out; 264 err = dsl_dataset_hold_obj(dp, 265 dsl_dir_phys(dd)->dd_head_dataset_obj, FTAG, &ds); 266 if (err == 0) { 267 err = dsl_dataset_hold_obj(dp, 268 dsl_dataset_phys(ds)->ds_prev_snap_obj, dp, 269 &dp->dp_origin_snap); 270 dsl_dataset_rele(ds, FTAG); 271 } 272 dsl_dir_rele(dd, dp); 273 if (err) 274 goto out; 275 } 276 277 if (spa_version(dp->dp_spa) >= SPA_VERSION_DEADLISTS) { 278 err = dsl_pool_open_special_dir(dp, FREE_DIR_NAME, 279 &dp->dp_free_dir); 280 if (err) 281 goto out; 282 283 err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT, 284 DMU_POOL_FREE_BPOBJ, sizeof (uint64_t), 1, &obj); 285 if (err) 286 goto out; 287 VERIFY0(bpobj_open(&dp->dp_free_bpobj, 288 dp->dp_meta_objset, obj)); 289 } 290 291 /* 292 * Note: errors ignored, because the leak dir will not exist if we 293 * have not encountered a leak yet. 294 */ 295 (void) dsl_pool_open_special_dir(dp, LEAK_DIR_NAME, 296 &dp->dp_leak_dir); 297 298 if (spa_feature_is_active(dp->dp_spa, SPA_FEATURE_ASYNC_DESTROY)) { 299 err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT, 300 DMU_POOL_BPTREE_OBJ, sizeof (uint64_t), 1, 301 &dp->dp_bptree_obj); 302 if (err != 0) 303 goto out; 304 } 305 306 if (spa_feature_is_active(dp->dp_spa, SPA_FEATURE_EMPTY_BPOBJ)) { 307 err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT, 308 DMU_POOL_EMPTY_BPOBJ, sizeof (uint64_t), 1, 309 &dp->dp_empty_bpobj); 310 if (err != 0) 311 goto out; 312 } 313 314 err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT, 315 DMU_POOL_TMP_USERREFS, sizeof (uint64_t), 1, 316 &dp->dp_tmp_userrefs_obj); 317 if (err == ENOENT) 318 err = 0; 319 if (err) 320 goto out; 321 322 err = dsl_scan_init(dp, dp->dp_tx.tx_open_txg); 323 324 out: 325 rrw_exit(&dp->dp_config_rwlock, FTAG); 326 return (err); 327 } 328 329 void 330 dsl_pool_close(dsl_pool_t *dp) 331 { 332 /* 333 * Drop our references from dsl_pool_open(). 334 * 335 * Since we held the origin_snap from "syncing" context (which 336 * includes pool-opening context), it actually only got a "ref" 337 * and not a hold, so just drop that here. 338 */ 339 if (dp->dp_origin_snap) 340 dsl_dataset_rele(dp->dp_origin_snap, dp); 341 if (dp->dp_mos_dir) 342 dsl_dir_rele(dp->dp_mos_dir, dp); 343 if (dp->dp_free_dir) 344 dsl_dir_rele(dp->dp_free_dir, dp); 345 if (dp->dp_leak_dir) 346 dsl_dir_rele(dp->dp_leak_dir, dp); 347 if (dp->dp_root_dir) 348 dsl_dir_rele(dp->dp_root_dir, dp); 349 350 bpobj_close(&dp->dp_free_bpobj); 351 352 /* undo the dmu_objset_open_impl(mos) from dsl_pool_open() */ 353 if (dp->dp_meta_objset) 354 dmu_objset_evict(dp->dp_meta_objset); 355 356 txg_list_destroy(&dp->dp_dirty_datasets); 357 txg_list_destroy(&dp->dp_dirty_zilogs); 358 txg_list_destroy(&dp->dp_sync_tasks); 359 txg_list_destroy(&dp->dp_dirty_dirs); 360 361 taskq_destroy(dp->dp_zil_clean_taskq); 362 taskq_destroy(dp->dp_sync_taskq); 363 364 /* 365 * We can't set retry to TRUE since we're explicitly specifying 366 * a spa to flush. This is good enough; any missed buffers for 367 * this spa won't cause trouble, and they'll eventually fall 368 * out of the ARC just like any other unused buffer. 369 */ 370 arc_flush(dp->dp_spa, FALSE); 371 372 txg_fini(dp); 373 dsl_scan_fini(dp); 374 dmu_buf_user_evict_wait(); 375 376 rrw_destroy(&dp->dp_config_rwlock); 377 mutex_destroy(&dp->dp_lock); 378 taskq_destroy(dp->dp_vnrele_taskq); 379 if (dp->dp_blkstats) 380 kmem_free(dp->dp_blkstats, sizeof (zfs_all_blkstats_t)); 381 kmem_free(dp, sizeof (dsl_pool_t)); 382 } 383 384 dsl_pool_t * 385 dsl_pool_create(spa_t *spa, nvlist_t *zplprops, uint64_t txg) 386 { 387 int err; 388 dsl_pool_t *dp = dsl_pool_open_impl(spa, txg); 389 dmu_tx_t *tx = dmu_tx_create_assigned(dp, txg); 390 objset_t *os; 391 dsl_dataset_t *ds; 392 uint64_t obj; 393 394 rrw_enter(&dp->dp_config_rwlock, RW_WRITER, FTAG); 395 396 /* create and open the MOS (meta-objset) */ 397 dp->dp_meta_objset = dmu_objset_create_impl(spa, 398 NULL, &dp->dp_meta_rootbp, DMU_OST_META, tx); 399 400 /* create the pool directory */ 401 err = zap_create_claim(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT, 402 DMU_OT_OBJECT_DIRECTORY, DMU_OT_NONE, 0, tx); 403 ASSERT0(err); 404 405 /* Initialize scan structures */ 406 VERIFY0(dsl_scan_init(dp, txg)); 407 408 /* create and open the root dir */ 409 dp->dp_root_dir_obj = dsl_dir_create_sync(dp, NULL, NULL, tx); 410 VERIFY0(dsl_dir_hold_obj(dp, dp->dp_root_dir_obj, 411 NULL, dp, &dp->dp_root_dir)); 412 413 /* create and open the meta-objset dir */ 414 (void) dsl_dir_create_sync(dp, dp->dp_root_dir, MOS_DIR_NAME, tx); 415 VERIFY0(dsl_pool_open_special_dir(dp, 416 MOS_DIR_NAME, &dp->dp_mos_dir)); 417 418 if (spa_version(spa) >= SPA_VERSION_DEADLISTS) { 419 /* create and open the free dir */ 420 (void) dsl_dir_create_sync(dp, dp->dp_root_dir, 421 FREE_DIR_NAME, tx); 422 VERIFY0(dsl_pool_open_special_dir(dp, 423 FREE_DIR_NAME, &dp->dp_free_dir)); 424 425 /* create and open the free_bplist */ 426 obj = bpobj_alloc(dp->dp_meta_objset, SPA_OLD_MAXBLOCKSIZE, tx); 427 VERIFY(zap_add(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT, 428 DMU_POOL_FREE_BPOBJ, sizeof (uint64_t), 1, &obj, tx) == 0); 429 VERIFY0(bpobj_open(&dp->dp_free_bpobj, 430 dp->dp_meta_objset, obj)); 431 } 432 433 if (spa_version(spa) >= SPA_VERSION_DSL_SCRUB) 434 dsl_pool_create_origin(dp, tx); 435 436 /* create the root dataset */ 437 obj = dsl_dataset_create_sync_dd(dp->dp_root_dir, NULL, 0, tx); 438 439 /* create the root objset */ 440 VERIFY0(dsl_dataset_hold_obj(dp, obj, FTAG, &ds)); 441 rrw_enter(&ds->ds_bp_rwlock, RW_READER, FTAG); 442 os = dmu_objset_create_impl(dp->dp_spa, ds, 443 dsl_dataset_get_blkptr(ds), DMU_OST_ZFS, tx); 444 rrw_exit(&ds->ds_bp_rwlock, FTAG); 445 #ifdef _KERNEL 446 zfs_create_fs(os, kcred, zplprops, tx); 447 #endif 448 dsl_dataset_rele(ds, FTAG); 449 450 dmu_tx_commit(tx); 451 452 rrw_exit(&dp->dp_config_rwlock, FTAG); 453 454 return (dp); 455 } 456 457 /* 458 * Account for the meta-objset space in its placeholder dsl_dir. 459 */ 460 void 461 dsl_pool_mos_diduse_space(dsl_pool_t *dp, 462 int64_t used, int64_t comp, int64_t uncomp) 463 { 464 ASSERT3U(comp, ==, uncomp); /* it's all metadata */ 465 mutex_enter(&dp->dp_lock); 466 dp->dp_mos_used_delta += used; 467 dp->dp_mos_compressed_delta += comp; 468 dp->dp_mos_uncompressed_delta += uncomp; 469 mutex_exit(&dp->dp_lock); 470 } 471 472 static void 473 dsl_pool_sync_mos(dsl_pool_t *dp, dmu_tx_t *tx) 474 { 475 zio_t *zio = zio_root(dp->dp_spa, NULL, NULL, ZIO_FLAG_MUSTSUCCEED); 476 dmu_objset_sync(dp->dp_meta_objset, zio, tx); 477 VERIFY0(zio_wait(zio)); 478 dprintf_bp(&dp->dp_meta_rootbp, "meta objset rootbp is %s", ""); 479 spa_set_rootblkptr(dp->dp_spa, &dp->dp_meta_rootbp); 480 } 481 482 static void 483 dsl_pool_dirty_delta(dsl_pool_t *dp, int64_t delta) 484 { 485 ASSERT(MUTEX_HELD(&dp->dp_lock)); 486 487 if (delta < 0) 488 ASSERT3U(-delta, <=, dp->dp_dirty_total); 489 490 dp->dp_dirty_total += delta; 491 492 /* 493 * Note: we signal even when increasing dp_dirty_total. 494 * This ensures forward progress -- each thread wakes the next waiter. 495 */ 496 if (dp->dp_dirty_total < zfs_dirty_data_max) 497 cv_signal(&dp->dp_spaceavail_cv); 498 } 499 500 void 501 dsl_pool_sync(dsl_pool_t *dp, uint64_t txg) 502 { 503 zio_t *zio; 504 dmu_tx_t *tx; 505 dsl_dir_t *dd; 506 dsl_dataset_t *ds; 507 objset_t *mos = dp->dp_meta_objset; 508 list_t synced_datasets; 509 510 list_create(&synced_datasets, sizeof (dsl_dataset_t), 511 offsetof(dsl_dataset_t, ds_synced_link)); 512 513 tx = dmu_tx_create_assigned(dp, txg); 514 515 /* 516 * Write out all dirty blocks of dirty datasets. 517 */ 518 zio = zio_root(dp->dp_spa, NULL, NULL, ZIO_FLAG_MUSTSUCCEED); 519 while ((ds = txg_list_remove(&dp->dp_dirty_datasets, txg)) != NULL) { 520 /* 521 * We must not sync any non-MOS datasets twice, because 522 * we may have taken a snapshot of them. However, we 523 * may sync newly-created datasets on pass 2. 524 */ 525 ASSERT(!list_link_active(&ds->ds_synced_link)); 526 list_insert_tail(&synced_datasets, ds); 527 dsl_dataset_sync(ds, zio, tx); 528 } 529 VERIFY0(zio_wait(zio)); 530 531 /* 532 * We have written all of the accounted dirty data, so our 533 * dp_space_towrite should now be zero. However, some seldom-used 534 * code paths do not adhere to this (e.g. dbuf_undirty(), also 535 * rounding error in dbuf_write_physdone). 536 * Shore up the accounting of any dirtied space now. 537 */ 538 dsl_pool_undirty_space(dp, dp->dp_dirty_pertxg[txg & TXG_MASK], txg); 539 540 /* 541 * Update the long range free counter after 542 * we're done syncing user data 543 */ 544 mutex_enter(&dp->dp_lock); 545 ASSERT(spa_sync_pass(dp->dp_spa) == 1 || 546 dp->dp_long_free_dirty_pertxg[txg & TXG_MASK] == 0); 547 dp->dp_long_free_dirty_pertxg[txg & TXG_MASK] = 0; 548 mutex_exit(&dp->dp_lock); 549 550 /* 551 * After the data blocks have been written (ensured by the zio_wait() 552 * above), update the user/group space accounting. This happens 553 * in tasks dispatched to dp_sync_taskq, so wait for them before 554 * continuing. 555 */ 556 for (ds = list_head(&synced_datasets); ds != NULL; 557 ds = list_next(&synced_datasets, ds)) { 558 dmu_objset_do_userquota_updates(ds->ds_objset, tx); 559 } 560 taskq_wait(dp->dp_sync_taskq); 561 562 /* 563 * Sync the datasets again to push out the changes due to 564 * userspace updates. This must be done before we process the 565 * sync tasks, so that any snapshots will have the correct 566 * user accounting information (and we won't get confused 567 * about which blocks are part of the snapshot). 568 */ 569 zio = zio_root(dp->dp_spa, NULL, NULL, ZIO_FLAG_MUSTSUCCEED); 570 while ((ds = txg_list_remove(&dp->dp_dirty_datasets, txg)) != NULL) { 571 ASSERT(list_link_active(&ds->ds_synced_link)); 572 dmu_buf_rele(ds->ds_dbuf, ds); 573 dsl_dataset_sync(ds, zio, tx); 574 } 575 VERIFY0(zio_wait(zio)); 576 577 /* 578 * Now that the datasets have been completely synced, we can 579 * clean up our in-memory structures accumulated while syncing: 580 * 581 * - move dead blocks from the pending deadlist to the on-disk deadlist 582 * - release hold from dsl_dataset_dirty() 583 */ 584 while ((ds = list_remove_head(&synced_datasets)) != NULL) { 585 dsl_dataset_sync_done(ds, tx); 586 } 587 while ((dd = txg_list_remove(&dp->dp_dirty_dirs, txg)) != NULL) { 588 dsl_dir_sync(dd, tx); 589 } 590 591 /* 592 * The MOS's space is accounted for in the pool/$MOS 593 * (dp_mos_dir). We can't modify the mos while we're syncing 594 * it, so we remember the deltas and apply them here. 595 */ 596 if (dp->dp_mos_used_delta != 0 || dp->dp_mos_compressed_delta != 0 || 597 dp->dp_mos_uncompressed_delta != 0) { 598 dsl_dir_diduse_space(dp->dp_mos_dir, DD_USED_HEAD, 599 dp->dp_mos_used_delta, 600 dp->dp_mos_compressed_delta, 601 dp->dp_mos_uncompressed_delta, tx); 602 dp->dp_mos_used_delta = 0; 603 dp->dp_mos_compressed_delta = 0; 604 dp->dp_mos_uncompressed_delta = 0; 605 } 606 607 if (!multilist_is_empty(mos->os_dirty_dnodes[txg & TXG_MASK])) { 608 dsl_pool_sync_mos(dp, tx); 609 } 610 611 /* 612 * If we modify a dataset in the same txg that we want to destroy it, 613 * its dsl_dir's dd_dbuf will be dirty, and thus have a hold on it. 614 * dsl_dir_destroy_check() will fail if there are unexpected holds. 615 * Therefore, we want to sync the MOS (thus syncing the dd_dbuf 616 * and clearing the hold on it) before we process the sync_tasks. 617 * The MOS data dirtied by the sync_tasks will be synced on the next 618 * pass. 619 */ 620 if (!txg_list_empty(&dp->dp_sync_tasks, txg)) { 621 dsl_sync_task_t *dst; 622 /* 623 * No more sync tasks should have been added while we 624 * were syncing. 625 */ 626 ASSERT3U(spa_sync_pass(dp->dp_spa), ==, 1); 627 while ((dst = txg_list_remove(&dp->dp_sync_tasks, txg)) != NULL) 628 dsl_sync_task_sync(dst, tx); 629 } 630 631 dmu_tx_commit(tx); 632 633 DTRACE_PROBE2(dsl_pool_sync__done, dsl_pool_t *dp, dp, uint64_t, txg); 634 } 635 636 void 637 dsl_pool_sync_done(dsl_pool_t *dp, uint64_t txg) 638 { 639 zilog_t *zilog; 640 641 while (zilog = txg_list_head(&dp->dp_dirty_zilogs, txg)) { 642 dsl_dataset_t *ds = dmu_objset_ds(zilog->zl_os); 643 /* 644 * We don't remove the zilog from the dp_dirty_zilogs 645 * list until after we've cleaned it. This ensures that 646 * callers of zilog_is_dirty() receive an accurate 647 * answer when they are racing with the spa sync thread. 648 */ 649 zil_clean(zilog, txg); 650 (void) txg_list_remove_this(&dp->dp_dirty_zilogs, zilog, txg); 651 ASSERT(!dmu_objset_is_dirty(zilog->zl_os, txg)); 652 dmu_buf_rele(ds->ds_dbuf, zilog); 653 } 654 ASSERT(!dmu_objset_is_dirty(dp->dp_meta_objset, txg)); 655 } 656 657 /* 658 * TRUE if the current thread is the tx_sync_thread or if we 659 * are being called from SPA context during pool initialization. 660 */ 661 int 662 dsl_pool_sync_context(dsl_pool_t *dp) 663 { 664 return (curthread == dp->dp_tx.tx_sync_thread || 665 spa_is_initializing(dp->dp_spa) || 666 taskq_member(dp->dp_sync_taskq, curthread)); 667 } 668 669 uint64_t 670 dsl_pool_adjustedsize(dsl_pool_t *dp, boolean_t netfree) 671 { 672 uint64_t space, resv; 673 674 /* 675 * If we're trying to assess whether it's OK to do a free, 676 * cut the reservation in half to allow forward progress 677 * (e.g. make it possible to rm(1) files from a full pool). 678 */ 679 space = spa_get_dspace(dp->dp_spa); 680 resv = spa_get_slop_space(dp->dp_spa); 681 if (netfree) 682 resv >>= 1; 683 684 return (space - resv); 685 } 686 687 boolean_t 688 dsl_pool_need_dirty_delay(dsl_pool_t *dp) 689 { 690 uint64_t delay_min_bytes = 691 zfs_dirty_data_max * zfs_delay_min_dirty_percent / 100; 692 boolean_t rv; 693 694 mutex_enter(&dp->dp_lock); 695 if (dp->dp_dirty_total > zfs_dirty_data_sync) 696 txg_kick(dp); 697 rv = (dp->dp_dirty_total > delay_min_bytes); 698 mutex_exit(&dp->dp_lock); 699 return (rv); 700 } 701 702 void 703 dsl_pool_dirty_space(dsl_pool_t *dp, int64_t space, dmu_tx_t *tx) 704 { 705 if (space > 0) { 706 mutex_enter(&dp->dp_lock); 707 dp->dp_dirty_pertxg[tx->tx_txg & TXG_MASK] += space; 708 dsl_pool_dirty_delta(dp, space); 709 mutex_exit(&dp->dp_lock); 710 } 711 } 712 713 void 714 dsl_pool_undirty_space(dsl_pool_t *dp, int64_t space, uint64_t txg) 715 { 716 ASSERT3S(space, >=, 0); 717 if (space == 0) 718 return; 719 mutex_enter(&dp->dp_lock); 720 if (dp->dp_dirty_pertxg[txg & TXG_MASK] < space) { 721 /* XXX writing something we didn't dirty? */ 722 space = dp->dp_dirty_pertxg[txg & TXG_MASK]; 723 } 724 ASSERT3U(dp->dp_dirty_pertxg[txg & TXG_MASK], >=, space); 725 dp->dp_dirty_pertxg[txg & TXG_MASK] -= space; 726 ASSERT3U(dp->dp_dirty_total, >=, space); 727 dsl_pool_dirty_delta(dp, -space); 728 mutex_exit(&dp->dp_lock); 729 } 730 731 /* ARGSUSED */ 732 static int 733 upgrade_clones_cb(dsl_pool_t *dp, dsl_dataset_t *hds, void *arg) 734 { 735 dmu_tx_t *tx = arg; 736 dsl_dataset_t *ds, *prev = NULL; 737 int err; 738 739 err = dsl_dataset_hold_obj(dp, hds->ds_object, FTAG, &ds); 740 if (err) 741 return (err); 742 743 while (dsl_dataset_phys(ds)->ds_prev_snap_obj != 0) { 744 err = dsl_dataset_hold_obj(dp, 745 dsl_dataset_phys(ds)->ds_prev_snap_obj, FTAG, &prev); 746 if (err) { 747 dsl_dataset_rele(ds, FTAG); 748 return (err); 749 } 750 751 if (dsl_dataset_phys(prev)->ds_next_snap_obj != ds->ds_object) 752 break; 753 dsl_dataset_rele(ds, FTAG); 754 ds = prev; 755 prev = NULL; 756 } 757 758 if (prev == NULL) { 759 prev = dp->dp_origin_snap; 760 761 /* 762 * The $ORIGIN can't have any data, or the accounting 763 * will be wrong. 764 */ 765 rrw_enter(&ds->ds_bp_rwlock, RW_READER, FTAG); 766 ASSERT0(dsl_dataset_phys(prev)->ds_bp.blk_birth); 767 rrw_exit(&ds->ds_bp_rwlock, FTAG); 768 769 /* The origin doesn't get attached to itself */ 770 if (ds->ds_object == prev->ds_object) { 771 dsl_dataset_rele(ds, FTAG); 772 return (0); 773 } 774 775 dmu_buf_will_dirty(ds->ds_dbuf, tx); 776 dsl_dataset_phys(ds)->ds_prev_snap_obj = prev->ds_object; 777 dsl_dataset_phys(ds)->ds_prev_snap_txg = 778 dsl_dataset_phys(prev)->ds_creation_txg; 779 780 dmu_buf_will_dirty(ds->ds_dir->dd_dbuf, tx); 781 dsl_dir_phys(ds->ds_dir)->dd_origin_obj = prev->ds_object; 782 783 dmu_buf_will_dirty(prev->ds_dbuf, tx); 784 dsl_dataset_phys(prev)->ds_num_children++; 785 786 if (dsl_dataset_phys(ds)->ds_next_snap_obj == 0) { 787 ASSERT(ds->ds_prev == NULL); 788 VERIFY0(dsl_dataset_hold_obj(dp, 789 dsl_dataset_phys(ds)->ds_prev_snap_obj, 790 ds, &ds->ds_prev)); 791 } 792 } 793 794 ASSERT3U(dsl_dir_phys(ds->ds_dir)->dd_origin_obj, ==, prev->ds_object); 795 ASSERT3U(dsl_dataset_phys(ds)->ds_prev_snap_obj, ==, prev->ds_object); 796 797 if (dsl_dataset_phys(prev)->ds_next_clones_obj == 0) { 798 dmu_buf_will_dirty(prev->ds_dbuf, tx); 799 dsl_dataset_phys(prev)->ds_next_clones_obj = 800 zap_create(dp->dp_meta_objset, 801 DMU_OT_NEXT_CLONES, DMU_OT_NONE, 0, tx); 802 } 803 VERIFY0(zap_add_int(dp->dp_meta_objset, 804 dsl_dataset_phys(prev)->ds_next_clones_obj, ds->ds_object, tx)); 805 806 dsl_dataset_rele(ds, FTAG); 807 if (prev != dp->dp_origin_snap) 808 dsl_dataset_rele(prev, FTAG); 809 return (0); 810 } 811 812 void 813 dsl_pool_upgrade_clones(dsl_pool_t *dp, dmu_tx_t *tx) 814 { 815 ASSERT(dmu_tx_is_syncing(tx)); 816 ASSERT(dp->dp_origin_snap != NULL); 817 818 VERIFY0(dmu_objset_find_dp(dp, dp->dp_root_dir_obj, upgrade_clones_cb, 819 tx, DS_FIND_CHILDREN | DS_FIND_SERIALIZE)); 820 } 821 822 /* ARGSUSED */ 823 static int 824 upgrade_dir_clones_cb(dsl_pool_t *dp, dsl_dataset_t *ds, void *arg) 825 { 826 dmu_tx_t *tx = arg; 827 objset_t *mos = dp->dp_meta_objset; 828 829 if (dsl_dir_phys(ds->ds_dir)->dd_origin_obj != 0) { 830 dsl_dataset_t *origin; 831 832 VERIFY0(dsl_dataset_hold_obj(dp, 833 dsl_dir_phys(ds->ds_dir)->dd_origin_obj, FTAG, &origin)); 834 835 if (dsl_dir_phys(origin->ds_dir)->dd_clones == 0) { 836 dmu_buf_will_dirty(origin->ds_dir->dd_dbuf, tx); 837 dsl_dir_phys(origin->ds_dir)->dd_clones = 838 zap_create(mos, DMU_OT_DSL_CLONES, DMU_OT_NONE, 839 0, tx); 840 } 841 842 VERIFY0(zap_add_int(dp->dp_meta_objset, 843 dsl_dir_phys(origin->ds_dir)->dd_clones, 844 ds->ds_object, tx)); 845 846 dsl_dataset_rele(origin, FTAG); 847 } 848 return (0); 849 } 850 851 void 852 dsl_pool_upgrade_dir_clones(dsl_pool_t *dp, dmu_tx_t *tx) 853 { 854 ASSERT(dmu_tx_is_syncing(tx)); 855 uint64_t obj; 856 857 (void) dsl_dir_create_sync(dp, dp->dp_root_dir, FREE_DIR_NAME, tx); 858 VERIFY0(dsl_pool_open_special_dir(dp, 859 FREE_DIR_NAME, &dp->dp_free_dir)); 860 861 /* 862 * We can't use bpobj_alloc(), because spa_version() still 863 * returns the old version, and we need a new-version bpobj with 864 * subobj support. So call dmu_object_alloc() directly. 865 */ 866 obj = dmu_object_alloc(dp->dp_meta_objset, DMU_OT_BPOBJ, 867 SPA_OLD_MAXBLOCKSIZE, DMU_OT_BPOBJ_HDR, sizeof (bpobj_phys_t), tx); 868 VERIFY0(zap_add(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT, 869 DMU_POOL_FREE_BPOBJ, sizeof (uint64_t), 1, &obj, tx)); 870 VERIFY0(bpobj_open(&dp->dp_free_bpobj, dp->dp_meta_objset, obj)); 871 872 VERIFY0(dmu_objset_find_dp(dp, dp->dp_root_dir_obj, 873 upgrade_dir_clones_cb, tx, DS_FIND_CHILDREN | DS_FIND_SERIALIZE)); 874 } 875 876 void 877 dsl_pool_create_origin(dsl_pool_t *dp, dmu_tx_t *tx) 878 { 879 uint64_t dsobj; 880 dsl_dataset_t *ds; 881 882 ASSERT(dmu_tx_is_syncing(tx)); 883 ASSERT(dp->dp_origin_snap == NULL); 884 ASSERT(rrw_held(&dp->dp_config_rwlock, RW_WRITER)); 885 886 /* create the origin dir, ds, & snap-ds */ 887 dsobj = dsl_dataset_create_sync(dp->dp_root_dir, ORIGIN_DIR_NAME, 888 NULL, 0, kcred, tx); 889 VERIFY0(dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds)); 890 dsl_dataset_snapshot_sync_impl(ds, ORIGIN_DIR_NAME, tx); 891 VERIFY0(dsl_dataset_hold_obj(dp, dsl_dataset_phys(ds)->ds_prev_snap_obj, 892 dp, &dp->dp_origin_snap)); 893 dsl_dataset_rele(ds, FTAG); 894 } 895 896 taskq_t * 897 dsl_pool_vnrele_taskq(dsl_pool_t *dp) 898 { 899 return (dp->dp_vnrele_taskq); 900 } 901 902 /* 903 * Walk through the pool-wide zap object of temporary snapshot user holds 904 * and release them. 905 */ 906 void 907 dsl_pool_clean_tmp_userrefs(dsl_pool_t *dp) 908 { 909 zap_attribute_t za; 910 zap_cursor_t zc; 911 objset_t *mos = dp->dp_meta_objset; 912 uint64_t zapobj = dp->dp_tmp_userrefs_obj; 913 nvlist_t *holds; 914 915 if (zapobj == 0) 916 return; 917 ASSERT(spa_version(dp->dp_spa) >= SPA_VERSION_USERREFS); 918 919 holds = fnvlist_alloc(); 920 921 for (zap_cursor_init(&zc, mos, zapobj); 922 zap_cursor_retrieve(&zc, &za) == 0; 923 zap_cursor_advance(&zc)) { 924 char *htag; 925 nvlist_t *tags; 926 927 htag = strchr(za.za_name, '-'); 928 *htag = '\0'; 929 ++htag; 930 if (nvlist_lookup_nvlist(holds, za.za_name, &tags) != 0) { 931 tags = fnvlist_alloc(); 932 fnvlist_add_boolean(tags, htag); 933 fnvlist_add_nvlist(holds, za.za_name, tags); 934 fnvlist_free(tags); 935 } else { 936 fnvlist_add_boolean(tags, htag); 937 } 938 } 939 dsl_dataset_user_release_tmp(dp, holds); 940 fnvlist_free(holds); 941 zap_cursor_fini(&zc); 942 } 943 944 /* 945 * Create the pool-wide zap object for storing temporary snapshot holds. 946 */ 947 void 948 dsl_pool_user_hold_create_obj(dsl_pool_t *dp, dmu_tx_t *tx) 949 { 950 objset_t *mos = dp->dp_meta_objset; 951 952 ASSERT(dp->dp_tmp_userrefs_obj == 0); 953 ASSERT(dmu_tx_is_syncing(tx)); 954 955 dp->dp_tmp_userrefs_obj = zap_create_link(mos, DMU_OT_USERREFS, 956 DMU_POOL_DIRECTORY_OBJECT, DMU_POOL_TMP_USERREFS, tx); 957 } 958 959 static int 960 dsl_pool_user_hold_rele_impl(dsl_pool_t *dp, uint64_t dsobj, 961 const char *tag, uint64_t now, dmu_tx_t *tx, boolean_t holding) 962 { 963 objset_t *mos = dp->dp_meta_objset; 964 uint64_t zapobj = dp->dp_tmp_userrefs_obj; 965 char *name; 966 int error; 967 968 ASSERT(spa_version(dp->dp_spa) >= SPA_VERSION_USERREFS); 969 ASSERT(dmu_tx_is_syncing(tx)); 970 971 /* 972 * If the pool was created prior to SPA_VERSION_USERREFS, the 973 * zap object for temporary holds might not exist yet. 974 */ 975 if (zapobj == 0) { 976 if (holding) { 977 dsl_pool_user_hold_create_obj(dp, tx); 978 zapobj = dp->dp_tmp_userrefs_obj; 979 } else { 980 return (SET_ERROR(ENOENT)); 981 } 982 } 983 984 name = kmem_asprintf("%llx-%s", (u_longlong_t)dsobj, tag); 985 if (holding) 986 error = zap_add(mos, zapobj, name, 8, 1, &now, tx); 987 else 988 error = zap_remove(mos, zapobj, name, tx); 989 strfree(name); 990 991 return (error); 992 } 993 994 /* 995 * Add a temporary hold for the given dataset object and tag. 996 */ 997 int 998 dsl_pool_user_hold(dsl_pool_t *dp, uint64_t dsobj, const char *tag, 999 uint64_t now, dmu_tx_t *tx) 1000 { 1001 return (dsl_pool_user_hold_rele_impl(dp, dsobj, tag, now, tx, B_TRUE)); 1002 } 1003 1004 /* 1005 * Release a temporary hold for the given dataset object and tag. 1006 */ 1007 int 1008 dsl_pool_user_release(dsl_pool_t *dp, uint64_t dsobj, const char *tag, 1009 dmu_tx_t *tx) 1010 { 1011 return (dsl_pool_user_hold_rele_impl(dp, dsobj, tag, NULL, 1012 tx, B_FALSE)); 1013 } 1014 1015 /* 1016 * DSL Pool Configuration Lock 1017 * 1018 * The dp_config_rwlock protects against changes to DSL state (e.g. dataset 1019 * creation / destruction / rename / property setting). It must be held for 1020 * read to hold a dataset or dsl_dir. I.e. you must call 1021 * dsl_pool_config_enter() or dsl_pool_hold() before calling 1022 * dsl_{dataset,dir}_hold{_obj}. In most circumstances, the dp_config_rwlock 1023 * must be held continuously until all datasets and dsl_dirs are released. 1024 * 1025 * The only exception to this rule is that if a "long hold" is placed on 1026 * a dataset, then the dp_config_rwlock may be dropped while the dataset 1027 * is still held. The long hold will prevent the dataset from being 1028 * destroyed -- the destroy will fail with EBUSY. A long hold can be 1029 * obtained by calling dsl_dataset_long_hold(), or by "owning" a dataset 1030 * (by calling dsl_{dataset,objset}_{try}own{_obj}). 1031 * 1032 * Legitimate long-holders (including owners) should be long-running, cancelable 1033 * tasks that should cause "zfs destroy" to fail. This includes DMU 1034 * consumers (i.e. a ZPL filesystem being mounted or ZVOL being open), 1035 * "zfs send", and "zfs diff". There are several other long-holders whose 1036 * uses are suboptimal (e.g. "zfs promote", and zil_suspend()). 1037 * 1038 * The usual formula for long-holding would be: 1039 * dsl_pool_hold() 1040 * dsl_dataset_hold() 1041 * ... perform checks ... 1042 * dsl_dataset_long_hold() 1043 * dsl_pool_rele() 1044 * ... perform long-running task ... 1045 * dsl_dataset_long_rele() 1046 * dsl_dataset_rele() 1047 * 1048 * Note that when the long hold is released, the dataset is still held but 1049 * the pool is not held. The dataset may change arbitrarily during this time 1050 * (e.g. it could be destroyed). Therefore you shouldn't do anything to the 1051 * dataset except release it. 1052 * 1053 * User-initiated operations (e.g. ioctls, zfs_ioc_*()) are either read-only 1054 * or modifying operations. 1055 * 1056 * Modifying operations should generally use dsl_sync_task(). The synctask 1057 * infrastructure enforces proper locking strategy with respect to the 1058 * dp_config_rwlock. See the comment above dsl_sync_task() for details. 1059 * 1060 * Read-only operations will manually hold the pool, then the dataset, obtain 1061 * information from the dataset, then release the pool and dataset. 1062 * dmu_objset_{hold,rele}() are convenience routines that also do the pool 1063 * hold/rele. 1064 */ 1065 1066 int 1067 dsl_pool_hold(const char *name, void *tag, dsl_pool_t **dp) 1068 { 1069 spa_t *spa; 1070 int error; 1071 1072 error = spa_open(name, &spa, tag); 1073 if (error == 0) { 1074 *dp = spa_get_dsl(spa); 1075 dsl_pool_config_enter(*dp, tag); 1076 } 1077 return (error); 1078 } 1079 1080 void 1081 dsl_pool_rele(dsl_pool_t *dp, void *tag) 1082 { 1083 dsl_pool_config_exit(dp, tag); 1084 spa_close(dp->dp_spa, tag); 1085 } 1086 1087 void 1088 dsl_pool_config_enter(dsl_pool_t *dp, void *tag) 1089 { 1090 /* 1091 * We use a "reentrant" reader-writer lock, but not reentrantly. 1092 * 1093 * The rrwlock can (with the track_all flag) track all reading threads, 1094 * which is very useful for debugging which code path failed to release 1095 * the lock, and for verifying that the *current* thread does hold 1096 * the lock. 1097 * 1098 * (Unlike a rwlock, which knows that N threads hold it for 1099 * read, but not *which* threads, so rw_held(RW_READER) returns TRUE 1100 * if any thread holds it for read, even if this thread doesn't). 1101 */ 1102 ASSERT(!rrw_held(&dp->dp_config_rwlock, RW_READER)); 1103 rrw_enter(&dp->dp_config_rwlock, RW_READER, tag); 1104 } 1105 1106 void 1107 dsl_pool_config_enter_prio(dsl_pool_t *dp, void *tag) 1108 { 1109 ASSERT(!rrw_held(&dp->dp_config_rwlock, RW_READER)); 1110 rrw_enter_read_prio(&dp->dp_config_rwlock, tag); 1111 } 1112 1113 void 1114 dsl_pool_config_exit(dsl_pool_t *dp, void *tag) 1115 { 1116 rrw_exit(&dp->dp_config_rwlock, tag); 1117 } 1118 1119 boolean_t 1120 dsl_pool_config_held(dsl_pool_t *dp) 1121 { 1122 return (RRW_LOCK_HELD(&dp->dp_config_rwlock)); 1123 } 1124 1125 boolean_t 1126 dsl_pool_config_held_writer(dsl_pool_t *dp) 1127 { 1128 return (RRW_WRITE_HELD(&dp->dp_config_rwlock)); 1129 } 1130