dsl_pool.c revision 263390
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) 2013 by Delphix. All rights reserved. 24 * Copyright (c) 2013 Steven Hartland. All rights reserved. 25 */ 26 27#include <sys/dsl_pool.h> 28#include <sys/dsl_dataset.h> 29#include <sys/dsl_prop.h> 30#include <sys/dsl_dir.h> 31#include <sys/dsl_synctask.h> 32#include <sys/dsl_scan.h> 33#include <sys/dnode.h> 34#include <sys/dmu_tx.h> 35#include <sys/dmu_objset.h> 36#include <sys/arc.h> 37#include <sys/zap.h> 38#include <sys/zio.h> 39#include <sys/zfs_context.h> 40#include <sys/fs/zfs.h> 41#include <sys/zfs_znode.h> 42#include <sys/spa_impl.h> 43#include <sys/dsl_deadlist.h> 44#include <sys/bptree.h> 45#include <sys/zfeature.h> 46#include <sys/zil_impl.h> 47#include <sys/dsl_userhold.h> 48 49/* 50 * ZFS Write Throttle 51 * ------------------ 52 * 53 * ZFS must limit the rate of incoming writes to the rate at which it is able 54 * to sync data modifications to the backend storage. Throttling by too much 55 * creates an artificial limit; throttling by too little can only be sustained 56 * for short periods and would lead to highly lumpy performance. On a per-pool 57 * basis, ZFS tracks the amount of modified (dirty) data. As operations change 58 * data, the amount of dirty data increases; as ZFS syncs out data, the amount 59 * of dirty data decreases. When the amount of dirty data exceeds a 60 * predetermined threshold further modifications are blocked until the amount 61 * of dirty data decreases (as data is synced out). 62 * 63 * The limit on dirty data is tunable, and should be adjusted according to 64 * both the IO capacity and available memory of the system. The larger the 65 * window, the more ZFS is able to aggregate and amortize metadata (and data) 66 * changes. However, memory is a limited resource, and allowing for more dirty 67 * data comes at the cost of keeping other useful data in memory (for example 68 * ZFS data cached by the ARC). 69 * 70 * Implementation 71 * 72 * As buffers are modified dsl_pool_willuse_space() increments both the per- 73 * txg (dp_dirty_pertxg[]) and poolwide (dp_dirty_total) accounting of 74 * dirty space used; dsl_pool_dirty_space() decrements those values as data 75 * is synced out from dsl_pool_sync(). While only the poolwide value is 76 * relevant, the per-txg value is useful for debugging. The tunable 77 * zfs_dirty_data_max determines the dirty space limit. Once that value is 78 * exceeded, new writes are halted until space frees up. 79 * 80 * The zfs_dirty_data_sync tunable dictates the threshold at which we 81 * ensure that there is a txg syncing (see the comment in txg.c for a full 82 * description of transaction group stages). 83 * 84 * The IO scheduler uses both the dirty space limit and current amount of 85 * dirty data as inputs. Those values affect the number of concurrent IOs ZFS 86 * issues. See the comment in vdev_queue.c for details of the IO scheduler. 87 * 88 * The delay is also calculated based on the amount of dirty data. See the 89 * comment above dmu_tx_delay() for details. 90 */ 91 92/* 93 * zfs_dirty_data_max will be set to zfs_dirty_data_max_percent% of all memory, 94 * capped at zfs_dirty_data_max_max. It can also be overridden in /etc/system. 95 */ 96uint64_t zfs_dirty_data_max; 97uint64_t zfs_dirty_data_max_max = 4ULL * 1024 * 1024 * 1024; 98int zfs_dirty_data_max_percent = 10; 99 100/* 101 * If there is at least this much dirty data, push out a txg. 102 */ 103uint64_t zfs_dirty_data_sync = 64 * 1024 * 1024; 104 105/* 106 * Once there is this amount of dirty data, the dmu_tx_delay() will kick in 107 * and delay each transaction. 108 * This value should be >= zfs_vdev_async_write_active_max_dirty_percent. 109 */ 110int zfs_delay_min_dirty_percent = 60; 111 112/* 113 * This controls how quickly the delay approaches infinity. 114 * Larger values cause it to delay less for a given amount of dirty data. 115 * Therefore larger values will cause there to be more dirty data for a 116 * given throughput. 117 * 118 * For the smoothest delay, this value should be about 1 billion divided 119 * by the maximum number of operations per second. This will smoothly 120 * handle between 10x and 1/10th this number. 121 * 122 * Note: zfs_delay_scale * zfs_dirty_data_max must be < 2^64, due to the 123 * multiply in dmu_tx_delay(). 124 */ 125uint64_t zfs_delay_scale = 1000 * 1000 * 1000 / 2000; 126 127 128/* 129 * XXX someday maybe turn these into #defines, and you have to tune it on a 130 * per-pool basis using zfs.conf. 131 */ 132 133 134SYSCTL_DECL(_vfs_zfs); 135#if 0 136TUNABLE_INT("vfs.zfs.no_write_throttle", &zfs_no_write_throttle); 137SYSCTL_INT(_vfs_zfs, OID_AUTO, no_write_throttle, CTLFLAG_RDTUN, 138 &zfs_no_write_throttle, 0, ""); 139TUNABLE_INT("vfs.zfs.write_limit_shift", &zfs_write_limit_shift); 140SYSCTL_INT(_vfs_zfs, OID_AUTO, write_limit_shift, CTLFLAG_RDTUN, 141 &zfs_write_limit_shift, 0, "2^N of physical memory"); 142SYSCTL_DECL(_vfs_zfs_txg); 143TUNABLE_INT("vfs.zfs.txg.synctime_ms", &zfs_txg_synctime_ms); 144SYSCTL_INT(_vfs_zfs_txg, OID_AUTO, synctime_ms, CTLFLAG_RDTUN, 145 &zfs_txg_synctime_ms, 0, "Target milliseconds to sync a txg"); 146 147TUNABLE_QUAD("vfs.zfs.write_limit_min", &zfs_write_limit_min); 148SYSCTL_UQUAD(_vfs_zfs, OID_AUTO, write_limit_min, CTLFLAG_RDTUN, 149 &zfs_write_limit_min, 0, "Minimum write limit"); 150TUNABLE_QUAD("vfs.zfs.write_limit_max", &zfs_write_limit_max); 151SYSCTL_UQUAD(_vfs_zfs, OID_AUTO, write_limit_max, CTLFLAG_RDTUN, 152 &zfs_write_limit_max, 0, "Maximum data payload per txg"); 153TUNABLE_QUAD("vfs.zfs.write_limit_inflated", &zfs_write_limit_inflated); 154SYSCTL_UQUAD(_vfs_zfs, OID_AUTO, write_limit_inflated, CTLFLAG_RDTUN, 155 &zfs_write_limit_inflated, 0, "Maximum size of the dynamic write limit"); 156TUNABLE_QUAD("vfs.zfs.write_limit_override", &zfs_write_limit_override); 157SYSCTL_UQUAD(_vfs_zfs, OID_AUTO, write_limit_override, CTLFLAG_RDTUN, 158 &zfs_write_limit_override, 0, 159 "Force a txg if dirty buffers exceed this value (bytes)"); 160#endif 161 162hrtime_t zfs_throttle_delay = MSEC2NSEC(10); 163hrtime_t zfs_throttle_resolution = MSEC2NSEC(10); 164 165int 166dsl_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 dp->dp_root_dir->dd_phys->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 180static dsl_pool_t * 181dsl_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, 193 offsetof(dsl_dataset_t, ds_dirty_link)); 194 txg_list_create(&dp->dp_dirty_zilogs, 195 offsetof(zilog_t, zl_dirty_link)); 196 txg_list_create(&dp->dp_dirty_dirs, 197 offsetof(dsl_dir_t, dd_dirty_link)); 198 txg_list_create(&dp->dp_sync_tasks, 199 offsetof(dsl_sync_task_t, dst_node)); 200 201 mutex_init(&dp->dp_lock, NULL, MUTEX_DEFAULT, NULL); 202 cv_init(&dp->dp_spaceavail_cv, NULL, CV_DEFAULT, NULL); 203 204 dp->dp_vnrele_taskq = taskq_create("zfs_vn_rele_taskq", 1, minclsyspri, 205 1, 4, 0); 206 207 return (dp); 208} 209 210int 211dsl_pool_init(spa_t *spa, uint64_t txg, dsl_pool_t **dpp) 212{ 213 int err; 214 dsl_pool_t *dp = dsl_pool_open_impl(spa, txg); 215 216 err = dmu_objset_open_impl(spa, NULL, &dp->dp_meta_rootbp, 217 &dp->dp_meta_objset); 218 if (err != 0) 219 dsl_pool_close(dp); 220 else 221 *dpp = dp; 222 223 return (err); 224} 225 226int 227dsl_pool_open(dsl_pool_t *dp) 228{ 229 int err; 230 dsl_dir_t *dd; 231 dsl_dataset_t *ds; 232 uint64_t obj; 233 234 rrw_enter(&dp->dp_config_rwlock, RW_WRITER, FTAG); 235 err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT, 236 DMU_POOL_ROOT_DATASET, sizeof (uint64_t), 1, 237 &dp->dp_root_dir_obj); 238 if (err) 239 goto out; 240 241 err = dsl_dir_hold_obj(dp, dp->dp_root_dir_obj, 242 NULL, dp, &dp->dp_root_dir); 243 if (err) 244 goto out; 245 246 err = dsl_pool_open_special_dir(dp, MOS_DIR_NAME, &dp->dp_mos_dir); 247 if (err) 248 goto out; 249 250 if (spa_version(dp->dp_spa) >= SPA_VERSION_ORIGIN) { 251 err = dsl_pool_open_special_dir(dp, ORIGIN_DIR_NAME, &dd); 252 if (err) 253 goto out; 254 err = dsl_dataset_hold_obj(dp, dd->dd_phys->dd_head_dataset_obj, 255 FTAG, &ds); 256 if (err == 0) { 257 err = dsl_dataset_hold_obj(dp, 258 ds->ds_phys->ds_prev_snap_obj, dp, 259 &dp->dp_origin_snap); 260 dsl_dataset_rele(ds, FTAG); 261 } 262 dsl_dir_rele(dd, dp); 263 if (err) 264 goto out; 265 } 266 267 if (spa_version(dp->dp_spa) >= SPA_VERSION_DEADLISTS) { 268 err = dsl_pool_open_special_dir(dp, FREE_DIR_NAME, 269 &dp->dp_free_dir); 270 if (err) 271 goto out; 272 273 err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT, 274 DMU_POOL_FREE_BPOBJ, sizeof (uint64_t), 1, &obj); 275 if (err) 276 goto out; 277 VERIFY0(bpobj_open(&dp->dp_free_bpobj, 278 dp->dp_meta_objset, obj)); 279 } 280 281 if (spa_feature_is_active(dp->dp_spa, SPA_FEATURE_ASYNC_DESTROY)) { 282 err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT, 283 DMU_POOL_BPTREE_OBJ, sizeof (uint64_t), 1, 284 &dp->dp_bptree_obj); 285 if (err != 0) 286 goto out; 287 } 288 289 if (spa_feature_is_active(dp->dp_spa, SPA_FEATURE_EMPTY_BPOBJ)) { 290 err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT, 291 DMU_POOL_EMPTY_BPOBJ, sizeof (uint64_t), 1, 292 &dp->dp_empty_bpobj); 293 if (err != 0) 294 goto out; 295 } 296 297 err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT, 298 DMU_POOL_TMP_USERREFS, sizeof (uint64_t), 1, 299 &dp->dp_tmp_userrefs_obj); 300 if (err == ENOENT) 301 err = 0; 302 if (err) 303 goto out; 304 305 err = dsl_scan_init(dp, dp->dp_tx.tx_open_txg); 306 307out: 308 rrw_exit(&dp->dp_config_rwlock, FTAG); 309 return (err); 310} 311 312void 313dsl_pool_close(dsl_pool_t *dp) 314{ 315 /* 316 * Drop our references from dsl_pool_open(). 317 * 318 * Since we held the origin_snap from "syncing" context (which 319 * includes pool-opening context), it actually only got a "ref" 320 * and not a hold, so just drop that here. 321 */ 322 if (dp->dp_origin_snap) 323 dsl_dataset_rele(dp->dp_origin_snap, dp); 324 if (dp->dp_mos_dir) 325 dsl_dir_rele(dp->dp_mos_dir, dp); 326 if (dp->dp_free_dir) 327 dsl_dir_rele(dp->dp_free_dir, dp); 328 if (dp->dp_root_dir) 329 dsl_dir_rele(dp->dp_root_dir, dp); 330 331 bpobj_close(&dp->dp_free_bpobj); 332 333 /* undo the dmu_objset_open_impl(mos) from dsl_pool_open() */ 334 if (dp->dp_meta_objset) 335 dmu_objset_evict(dp->dp_meta_objset); 336 337 txg_list_destroy(&dp->dp_dirty_datasets); 338 txg_list_destroy(&dp->dp_dirty_zilogs); 339 txg_list_destroy(&dp->dp_sync_tasks); 340 txg_list_destroy(&dp->dp_dirty_dirs); 341 342 arc_flush(dp->dp_spa); 343 txg_fini(dp); 344 dsl_scan_fini(dp); 345 rrw_destroy(&dp->dp_config_rwlock); 346 mutex_destroy(&dp->dp_lock); 347 taskq_destroy(dp->dp_vnrele_taskq); 348 if (dp->dp_blkstats) 349 kmem_free(dp->dp_blkstats, sizeof (zfs_all_blkstats_t)); 350 kmem_free(dp, sizeof (dsl_pool_t)); 351} 352 353dsl_pool_t * 354dsl_pool_create(spa_t *spa, nvlist_t *zplprops, uint64_t txg) 355{ 356 int err; 357 dsl_pool_t *dp = dsl_pool_open_impl(spa, txg); 358 dmu_tx_t *tx = dmu_tx_create_assigned(dp, txg); 359 objset_t *os; 360 dsl_dataset_t *ds; 361 uint64_t obj; 362 363 rrw_enter(&dp->dp_config_rwlock, RW_WRITER, FTAG); 364 365 /* create and open the MOS (meta-objset) */ 366 dp->dp_meta_objset = dmu_objset_create_impl(spa, 367 NULL, &dp->dp_meta_rootbp, DMU_OST_META, tx); 368 369 /* create the pool directory */ 370 err = zap_create_claim(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT, 371 DMU_OT_OBJECT_DIRECTORY, DMU_OT_NONE, 0, tx); 372 ASSERT0(err); 373 374 /* Initialize scan structures */ 375 VERIFY0(dsl_scan_init(dp, txg)); 376 377 /* create and open the root dir */ 378 dp->dp_root_dir_obj = dsl_dir_create_sync(dp, NULL, NULL, tx); 379 VERIFY0(dsl_dir_hold_obj(dp, dp->dp_root_dir_obj, 380 NULL, dp, &dp->dp_root_dir)); 381 382 /* create and open the meta-objset dir */ 383 (void) dsl_dir_create_sync(dp, dp->dp_root_dir, MOS_DIR_NAME, tx); 384 VERIFY0(dsl_pool_open_special_dir(dp, 385 MOS_DIR_NAME, &dp->dp_mos_dir)); 386 387 if (spa_version(spa) >= SPA_VERSION_DEADLISTS) { 388 /* create and open the free dir */ 389 (void) dsl_dir_create_sync(dp, dp->dp_root_dir, 390 FREE_DIR_NAME, tx); 391 VERIFY0(dsl_pool_open_special_dir(dp, 392 FREE_DIR_NAME, &dp->dp_free_dir)); 393 394 /* create and open the free_bplist */ 395 obj = bpobj_alloc(dp->dp_meta_objset, SPA_MAXBLOCKSIZE, tx); 396 VERIFY(zap_add(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT, 397 DMU_POOL_FREE_BPOBJ, sizeof (uint64_t), 1, &obj, tx) == 0); 398 VERIFY0(bpobj_open(&dp->dp_free_bpobj, 399 dp->dp_meta_objset, obj)); 400 } 401 402 if (spa_version(spa) >= SPA_VERSION_DSL_SCRUB) 403 dsl_pool_create_origin(dp, tx); 404 405 /* create the root dataset */ 406 obj = dsl_dataset_create_sync_dd(dp->dp_root_dir, NULL, 0, tx); 407 408 /* create the root objset */ 409 VERIFY0(dsl_dataset_hold_obj(dp, obj, FTAG, &ds)); 410 os = dmu_objset_create_impl(dp->dp_spa, ds, 411 dsl_dataset_get_blkptr(ds), DMU_OST_ZFS, tx); 412#ifdef _KERNEL 413 zfs_create_fs(os, kcred, zplprops, tx); 414#endif 415 dsl_dataset_rele(ds, FTAG); 416 417 dmu_tx_commit(tx); 418 419 rrw_exit(&dp->dp_config_rwlock, FTAG); 420 421 return (dp); 422} 423 424/* 425 * Account for the meta-objset space in its placeholder dsl_dir. 426 */ 427void 428dsl_pool_mos_diduse_space(dsl_pool_t *dp, 429 int64_t used, int64_t comp, int64_t uncomp) 430{ 431 ASSERT3U(comp, ==, uncomp); /* it's all metadata */ 432 mutex_enter(&dp->dp_lock); 433 dp->dp_mos_used_delta += used; 434 dp->dp_mos_compressed_delta += comp; 435 dp->dp_mos_uncompressed_delta += uncomp; 436 mutex_exit(&dp->dp_lock); 437} 438 439static int 440deadlist_enqueue_cb(void *arg, const blkptr_t *bp, dmu_tx_t *tx) 441{ 442 dsl_deadlist_t *dl = arg; 443 dsl_deadlist_insert(dl, bp, tx); 444 return (0); 445} 446 447static void 448dsl_pool_sync_mos(dsl_pool_t *dp, dmu_tx_t *tx) 449{ 450 zio_t *zio = zio_root(dp->dp_spa, NULL, NULL, ZIO_FLAG_MUSTSUCCEED); 451 dmu_objset_sync(dp->dp_meta_objset, zio, tx); 452 VERIFY0(zio_wait(zio)); 453 dprintf_bp(&dp->dp_meta_rootbp, "meta objset rootbp is %s", ""); 454 spa_set_rootblkptr(dp->dp_spa, &dp->dp_meta_rootbp); 455} 456 457static void 458dsl_pool_dirty_delta(dsl_pool_t *dp, int64_t delta) 459{ 460 ASSERT(MUTEX_HELD(&dp->dp_lock)); 461 462 if (delta < 0) 463 ASSERT3U(-delta, <=, dp->dp_dirty_total); 464 465 dp->dp_dirty_total += delta; 466 467 /* 468 * Note: we signal even when increasing dp_dirty_total. 469 * This ensures forward progress -- each thread wakes the next waiter. 470 */ 471 if (dp->dp_dirty_total <= zfs_dirty_data_max) 472 cv_signal(&dp->dp_spaceavail_cv); 473} 474 475void 476dsl_pool_sync(dsl_pool_t *dp, uint64_t txg) 477{ 478 zio_t *zio; 479 dmu_tx_t *tx; 480 dsl_dir_t *dd; 481 dsl_dataset_t *ds; 482 objset_t *mos = dp->dp_meta_objset; 483 list_t synced_datasets; 484 485 list_create(&synced_datasets, sizeof (dsl_dataset_t), 486 offsetof(dsl_dataset_t, ds_synced_link)); 487 488 tx = dmu_tx_create_assigned(dp, txg); 489 490 /* 491 * Write out all dirty blocks of dirty datasets. 492 */ 493 zio = zio_root(dp->dp_spa, NULL, NULL, ZIO_FLAG_MUSTSUCCEED); 494 while ((ds = txg_list_remove(&dp->dp_dirty_datasets, txg)) != NULL) { 495 /* 496 * We must not sync any non-MOS datasets twice, because 497 * we may have taken a snapshot of them. However, we 498 * may sync newly-created datasets on pass 2. 499 */ 500 ASSERT(!list_link_active(&ds->ds_synced_link)); 501 list_insert_tail(&synced_datasets, ds); 502 dsl_dataset_sync(ds, zio, tx); 503 } 504 VERIFY0(zio_wait(zio)); 505 506 /* 507 * We have written all of the accounted dirty data, so our 508 * dp_space_towrite should now be zero. However, some seldom-used 509 * code paths do not adhere to this (e.g. dbuf_undirty(), also 510 * rounding error in dbuf_write_physdone). 511 * Shore up the accounting of any dirtied space now. 512 */ 513 dsl_pool_undirty_space(dp, dp->dp_dirty_pertxg[txg & TXG_MASK], txg); 514 515 /* 516 * After the data blocks have been written (ensured by the zio_wait() 517 * above), update the user/group space accounting. 518 */ 519 for (ds = list_head(&synced_datasets); ds != NULL; 520 ds = list_next(&synced_datasets, ds)) { 521 dmu_objset_do_userquota_updates(ds->ds_objset, tx); 522 } 523 524 /* 525 * Sync the datasets again to push out the changes due to 526 * userspace updates. This must be done before we process the 527 * sync tasks, so that any snapshots will have the correct 528 * user accounting information (and we won't get confused 529 * about which blocks are part of the snapshot). 530 */ 531 zio = zio_root(dp->dp_spa, NULL, NULL, ZIO_FLAG_MUSTSUCCEED); 532 while ((ds = txg_list_remove(&dp->dp_dirty_datasets, txg)) != NULL) { 533 ASSERT(list_link_active(&ds->ds_synced_link)); 534 dmu_buf_rele(ds->ds_dbuf, ds); 535 dsl_dataset_sync(ds, zio, tx); 536 } 537 VERIFY0(zio_wait(zio)); 538 539 /* 540 * Now that the datasets have been completely synced, we can 541 * clean up our in-memory structures accumulated while syncing: 542 * 543 * - move dead blocks from the pending deadlist to the on-disk deadlist 544 * - release hold from dsl_dataset_dirty() 545 */ 546 while ((ds = list_remove_head(&synced_datasets)) != NULL) { 547 objset_t *os = ds->ds_objset; 548 bplist_iterate(&ds->ds_pending_deadlist, 549 deadlist_enqueue_cb, &ds->ds_deadlist, tx); 550 ASSERT(!dmu_objset_is_dirty(os, txg)); 551 dmu_buf_rele(ds->ds_dbuf, ds); 552 } 553 while ((dd = txg_list_remove(&dp->dp_dirty_dirs, txg)) != NULL) { 554 dsl_dir_sync(dd, tx); 555 } 556 557 /* 558 * The MOS's space is accounted for in the pool/$MOS 559 * (dp_mos_dir). We can't modify the mos while we're syncing 560 * it, so we remember the deltas and apply them here. 561 */ 562 if (dp->dp_mos_used_delta != 0 || dp->dp_mos_compressed_delta != 0 || 563 dp->dp_mos_uncompressed_delta != 0) { 564 dsl_dir_diduse_space(dp->dp_mos_dir, DD_USED_HEAD, 565 dp->dp_mos_used_delta, 566 dp->dp_mos_compressed_delta, 567 dp->dp_mos_uncompressed_delta, tx); 568 dp->dp_mos_used_delta = 0; 569 dp->dp_mos_compressed_delta = 0; 570 dp->dp_mos_uncompressed_delta = 0; 571 } 572 573 if (list_head(&mos->os_dirty_dnodes[txg & TXG_MASK]) != NULL || 574 list_head(&mos->os_free_dnodes[txg & TXG_MASK]) != NULL) { 575 dsl_pool_sync_mos(dp, tx); 576 } 577 578 /* 579 * If we modify a dataset in the same txg that we want to destroy it, 580 * its dsl_dir's dd_dbuf will be dirty, and thus have a hold on it. 581 * dsl_dir_destroy_check() will fail if there are unexpected holds. 582 * Therefore, we want to sync the MOS (thus syncing the dd_dbuf 583 * and clearing the hold on it) before we process the sync_tasks. 584 * The MOS data dirtied by the sync_tasks will be synced on the next 585 * pass. 586 */ 587 if (!txg_list_empty(&dp->dp_sync_tasks, txg)) { 588 dsl_sync_task_t *dst; 589 /* 590 * No more sync tasks should have been added while we 591 * were syncing. 592 */ 593 ASSERT3U(spa_sync_pass(dp->dp_spa), ==, 1); 594 while ((dst = txg_list_remove(&dp->dp_sync_tasks, txg)) != NULL) 595 dsl_sync_task_sync(dst, tx); 596 } 597 598 dmu_tx_commit(tx); 599 600 DTRACE_PROBE2(dsl_pool_sync__done, dsl_pool_t *dp, dp, uint64_t, txg); 601} 602 603void 604dsl_pool_sync_done(dsl_pool_t *dp, uint64_t txg) 605{ 606 zilog_t *zilog; 607 608 while (zilog = txg_list_remove(&dp->dp_dirty_zilogs, txg)) { 609 dsl_dataset_t *ds = dmu_objset_ds(zilog->zl_os); 610 zil_clean(zilog, txg); 611 ASSERT(!dmu_objset_is_dirty(zilog->zl_os, txg)); 612 dmu_buf_rele(ds->ds_dbuf, zilog); 613 } 614 ASSERT(!dmu_objset_is_dirty(dp->dp_meta_objset, txg)); 615} 616 617/* 618 * TRUE if the current thread is the tx_sync_thread or if we 619 * are being called from SPA context during pool initialization. 620 */ 621int 622dsl_pool_sync_context(dsl_pool_t *dp) 623{ 624 return (curthread == dp->dp_tx.tx_sync_thread || 625 spa_is_initializing(dp->dp_spa)); 626} 627 628uint64_t 629dsl_pool_adjustedsize(dsl_pool_t *dp, boolean_t netfree) 630{ 631 uint64_t space, resv; 632 633 /* 634 * Reserve about 1.6% (1/64), or at least 32MB, for allocation 635 * efficiency. 636 * XXX The intent log is not accounted for, so it must fit 637 * within this slop. 638 * 639 * If we're trying to assess whether it's OK to do a free, 640 * cut the reservation in half to allow forward progress 641 * (e.g. make it possible to rm(1) files from a full pool). 642 */ 643 space = spa_get_dspace(dp->dp_spa); 644 resv = MAX(space >> 6, SPA_MINDEVSIZE >> 1); 645 if (netfree) 646 resv >>= 1; 647 648 return (space - resv); 649} 650 651boolean_t 652dsl_pool_need_dirty_delay(dsl_pool_t *dp) 653{ 654 uint64_t delay_min_bytes = 655 zfs_dirty_data_max * zfs_delay_min_dirty_percent / 100; 656 boolean_t rv; 657 658 mutex_enter(&dp->dp_lock); 659 if (dp->dp_dirty_total > zfs_dirty_data_sync) 660 txg_kick(dp); 661 rv = (dp->dp_dirty_total > delay_min_bytes); 662 mutex_exit(&dp->dp_lock); 663 return (rv); 664} 665 666void 667dsl_pool_dirty_space(dsl_pool_t *dp, int64_t space, dmu_tx_t *tx) 668{ 669 if (space > 0) { 670 mutex_enter(&dp->dp_lock); 671 dp->dp_dirty_pertxg[tx->tx_txg & TXG_MASK] += space; 672 dsl_pool_dirty_delta(dp, space); 673 mutex_exit(&dp->dp_lock); 674 } 675} 676 677void 678dsl_pool_undirty_space(dsl_pool_t *dp, int64_t space, uint64_t txg) 679{ 680 ASSERT3S(space, >=, 0); 681 if (space == 0) 682 return; 683 mutex_enter(&dp->dp_lock); 684 if (dp->dp_dirty_pertxg[txg & TXG_MASK] < space) { 685 /* XXX writing something we didn't dirty? */ 686 space = dp->dp_dirty_pertxg[txg & TXG_MASK]; 687 } 688 ASSERT3U(dp->dp_dirty_pertxg[txg & TXG_MASK], >=, space); 689 dp->dp_dirty_pertxg[txg & TXG_MASK] -= space; 690 ASSERT3U(dp->dp_dirty_total, >=, space); 691 dsl_pool_dirty_delta(dp, -space); 692 mutex_exit(&dp->dp_lock); 693} 694 695/* ARGSUSED */ 696static int 697upgrade_clones_cb(dsl_pool_t *dp, dsl_dataset_t *hds, void *arg) 698{ 699 dmu_tx_t *tx = arg; 700 dsl_dataset_t *ds, *prev = NULL; 701 int err; 702 703 err = dsl_dataset_hold_obj(dp, hds->ds_object, FTAG, &ds); 704 if (err) 705 return (err); 706 707 while (ds->ds_phys->ds_prev_snap_obj != 0) { 708 err = dsl_dataset_hold_obj(dp, ds->ds_phys->ds_prev_snap_obj, 709 FTAG, &prev); 710 if (err) { 711 dsl_dataset_rele(ds, FTAG); 712 return (err); 713 } 714 715 if (prev->ds_phys->ds_next_snap_obj != ds->ds_object) 716 break; 717 dsl_dataset_rele(ds, FTAG); 718 ds = prev; 719 prev = NULL; 720 } 721 722 if (prev == NULL) { 723 prev = dp->dp_origin_snap; 724 725 /* 726 * The $ORIGIN can't have any data, or the accounting 727 * will be wrong. 728 */ 729 ASSERT0(prev->ds_phys->ds_bp.blk_birth); 730 731 /* The origin doesn't get attached to itself */ 732 if (ds->ds_object == prev->ds_object) { 733 dsl_dataset_rele(ds, FTAG); 734 return (0); 735 } 736 737 dmu_buf_will_dirty(ds->ds_dbuf, tx); 738 ds->ds_phys->ds_prev_snap_obj = prev->ds_object; 739 ds->ds_phys->ds_prev_snap_txg = prev->ds_phys->ds_creation_txg; 740 741 dmu_buf_will_dirty(ds->ds_dir->dd_dbuf, tx); 742 ds->ds_dir->dd_phys->dd_origin_obj = prev->ds_object; 743 744 dmu_buf_will_dirty(prev->ds_dbuf, tx); 745 prev->ds_phys->ds_num_children++; 746 747 if (ds->ds_phys->ds_next_snap_obj == 0) { 748 ASSERT(ds->ds_prev == NULL); 749 VERIFY0(dsl_dataset_hold_obj(dp, 750 ds->ds_phys->ds_prev_snap_obj, ds, &ds->ds_prev)); 751 } 752 } 753 754 ASSERT3U(ds->ds_dir->dd_phys->dd_origin_obj, ==, prev->ds_object); 755 ASSERT3U(ds->ds_phys->ds_prev_snap_obj, ==, prev->ds_object); 756 757 if (prev->ds_phys->ds_next_clones_obj == 0) { 758 dmu_buf_will_dirty(prev->ds_dbuf, tx); 759 prev->ds_phys->ds_next_clones_obj = 760 zap_create(dp->dp_meta_objset, 761 DMU_OT_NEXT_CLONES, DMU_OT_NONE, 0, tx); 762 } 763 VERIFY0(zap_add_int(dp->dp_meta_objset, 764 prev->ds_phys->ds_next_clones_obj, ds->ds_object, tx)); 765 766 dsl_dataset_rele(ds, FTAG); 767 if (prev != dp->dp_origin_snap) 768 dsl_dataset_rele(prev, FTAG); 769 return (0); 770} 771 772void 773dsl_pool_upgrade_clones(dsl_pool_t *dp, dmu_tx_t *tx) 774{ 775 ASSERT(dmu_tx_is_syncing(tx)); 776 ASSERT(dp->dp_origin_snap != NULL); 777 778 VERIFY0(dmu_objset_find_dp(dp, dp->dp_root_dir_obj, upgrade_clones_cb, 779 tx, DS_FIND_CHILDREN)); 780} 781 782/* ARGSUSED */ 783static int 784upgrade_dir_clones_cb(dsl_pool_t *dp, dsl_dataset_t *ds, void *arg) 785{ 786 dmu_tx_t *tx = arg; 787 objset_t *mos = dp->dp_meta_objset; 788 789 if (ds->ds_dir->dd_phys->dd_origin_obj != 0) { 790 dsl_dataset_t *origin; 791 792 VERIFY0(dsl_dataset_hold_obj(dp, 793 ds->ds_dir->dd_phys->dd_origin_obj, FTAG, &origin)); 794 795 if (origin->ds_dir->dd_phys->dd_clones == 0) { 796 dmu_buf_will_dirty(origin->ds_dir->dd_dbuf, tx); 797 origin->ds_dir->dd_phys->dd_clones = zap_create(mos, 798 DMU_OT_DSL_CLONES, DMU_OT_NONE, 0, tx); 799 } 800 801 VERIFY0(zap_add_int(dp->dp_meta_objset, 802 origin->ds_dir->dd_phys->dd_clones, ds->ds_object, tx)); 803 804 dsl_dataset_rele(origin, FTAG); 805 } 806 return (0); 807} 808 809void 810dsl_pool_upgrade_dir_clones(dsl_pool_t *dp, dmu_tx_t *tx) 811{ 812 ASSERT(dmu_tx_is_syncing(tx)); 813 uint64_t obj; 814 815 (void) dsl_dir_create_sync(dp, dp->dp_root_dir, FREE_DIR_NAME, tx); 816 VERIFY0(dsl_pool_open_special_dir(dp, 817 FREE_DIR_NAME, &dp->dp_free_dir)); 818 819 /* 820 * We can't use bpobj_alloc(), because spa_version() still 821 * returns the old version, and we need a new-version bpobj with 822 * subobj support. So call dmu_object_alloc() directly. 823 */ 824 obj = dmu_object_alloc(dp->dp_meta_objset, DMU_OT_BPOBJ, 825 SPA_MAXBLOCKSIZE, DMU_OT_BPOBJ_HDR, sizeof (bpobj_phys_t), tx); 826 VERIFY0(zap_add(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT, 827 DMU_POOL_FREE_BPOBJ, sizeof (uint64_t), 1, &obj, tx)); 828 VERIFY0(bpobj_open(&dp->dp_free_bpobj, dp->dp_meta_objset, obj)); 829 830 VERIFY0(dmu_objset_find_dp(dp, dp->dp_root_dir_obj, 831 upgrade_dir_clones_cb, tx, DS_FIND_CHILDREN)); 832} 833 834void 835dsl_pool_create_origin(dsl_pool_t *dp, dmu_tx_t *tx) 836{ 837 uint64_t dsobj; 838 dsl_dataset_t *ds; 839 840 ASSERT(dmu_tx_is_syncing(tx)); 841 ASSERT(dp->dp_origin_snap == NULL); 842 ASSERT(rrw_held(&dp->dp_config_rwlock, RW_WRITER)); 843 844 /* create the origin dir, ds, & snap-ds */ 845 dsobj = dsl_dataset_create_sync(dp->dp_root_dir, ORIGIN_DIR_NAME, 846 NULL, 0, kcred, tx); 847 VERIFY0(dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds)); 848 dsl_dataset_snapshot_sync_impl(ds, ORIGIN_DIR_NAME, tx); 849 VERIFY0(dsl_dataset_hold_obj(dp, ds->ds_phys->ds_prev_snap_obj, 850 dp, &dp->dp_origin_snap)); 851 dsl_dataset_rele(ds, FTAG); 852} 853 854taskq_t * 855dsl_pool_vnrele_taskq(dsl_pool_t *dp) 856{ 857 return (dp->dp_vnrele_taskq); 858} 859 860/* 861 * Walk through the pool-wide zap object of temporary snapshot user holds 862 * and release them. 863 */ 864void 865dsl_pool_clean_tmp_userrefs(dsl_pool_t *dp) 866{ 867 zap_attribute_t za; 868 zap_cursor_t zc; 869 objset_t *mos = dp->dp_meta_objset; 870 uint64_t zapobj = dp->dp_tmp_userrefs_obj; 871 nvlist_t *holds; 872 873 if (zapobj == 0) 874 return; 875 ASSERT(spa_version(dp->dp_spa) >= SPA_VERSION_USERREFS); 876 877 holds = fnvlist_alloc(); 878 879 for (zap_cursor_init(&zc, mos, zapobj); 880 zap_cursor_retrieve(&zc, &za) == 0; 881 zap_cursor_advance(&zc)) { 882 char *htag; 883 nvlist_t *tags; 884 885 htag = strchr(za.za_name, '-'); 886 *htag = '\0'; 887 ++htag; 888 if (nvlist_lookup_nvlist(holds, za.za_name, &tags) != 0) { 889 tags = fnvlist_alloc(); 890 fnvlist_add_boolean(tags, htag); 891 fnvlist_add_nvlist(holds, za.za_name, tags); 892 fnvlist_free(tags); 893 } else { 894 fnvlist_add_boolean(tags, htag); 895 } 896 } 897 dsl_dataset_user_release_tmp(dp, holds); 898 fnvlist_free(holds); 899 zap_cursor_fini(&zc); 900} 901 902/* 903 * Create the pool-wide zap object for storing temporary snapshot holds. 904 */ 905void 906dsl_pool_user_hold_create_obj(dsl_pool_t *dp, dmu_tx_t *tx) 907{ 908 objset_t *mos = dp->dp_meta_objset; 909 910 ASSERT(dp->dp_tmp_userrefs_obj == 0); 911 ASSERT(dmu_tx_is_syncing(tx)); 912 913 dp->dp_tmp_userrefs_obj = zap_create_link(mos, DMU_OT_USERREFS, 914 DMU_POOL_DIRECTORY_OBJECT, DMU_POOL_TMP_USERREFS, tx); 915} 916 917static int 918dsl_pool_user_hold_rele_impl(dsl_pool_t *dp, uint64_t dsobj, 919 const char *tag, uint64_t now, dmu_tx_t *tx, boolean_t holding) 920{ 921 objset_t *mos = dp->dp_meta_objset; 922 uint64_t zapobj = dp->dp_tmp_userrefs_obj; 923 char *name; 924 int error; 925 926 ASSERT(spa_version(dp->dp_spa) >= SPA_VERSION_USERREFS); 927 ASSERT(dmu_tx_is_syncing(tx)); 928 929 /* 930 * If the pool was created prior to SPA_VERSION_USERREFS, the 931 * zap object for temporary holds might not exist yet. 932 */ 933 if (zapobj == 0) { 934 if (holding) { 935 dsl_pool_user_hold_create_obj(dp, tx); 936 zapobj = dp->dp_tmp_userrefs_obj; 937 } else { 938 return (SET_ERROR(ENOENT)); 939 } 940 } 941 942 name = kmem_asprintf("%llx-%s", (u_longlong_t)dsobj, tag); 943 if (holding) 944 error = zap_add(mos, zapobj, name, 8, 1, &now, tx); 945 else 946 error = zap_remove(mos, zapobj, name, tx); 947 strfree(name); 948 949 return (error); 950} 951 952/* 953 * Add a temporary hold for the given dataset object and tag. 954 */ 955int 956dsl_pool_user_hold(dsl_pool_t *dp, uint64_t dsobj, const char *tag, 957 uint64_t now, dmu_tx_t *tx) 958{ 959 return (dsl_pool_user_hold_rele_impl(dp, dsobj, tag, now, tx, B_TRUE)); 960} 961 962/* 963 * Release a temporary hold for the given dataset object and tag. 964 */ 965int 966dsl_pool_user_release(dsl_pool_t *dp, uint64_t dsobj, const char *tag, 967 dmu_tx_t *tx) 968{ 969 return (dsl_pool_user_hold_rele_impl(dp, dsobj, tag, 0, 970 tx, B_FALSE)); 971} 972 973/* 974 * DSL Pool Configuration Lock 975 * 976 * The dp_config_rwlock protects against changes to DSL state (e.g. dataset 977 * creation / destruction / rename / property setting). It must be held for 978 * read to hold a dataset or dsl_dir. I.e. you must call 979 * dsl_pool_config_enter() or dsl_pool_hold() before calling 980 * dsl_{dataset,dir}_hold{_obj}. In most circumstances, the dp_config_rwlock 981 * must be held continuously until all datasets and dsl_dirs are released. 982 * 983 * The only exception to this rule is that if a "long hold" is placed on 984 * a dataset, then the dp_config_rwlock may be dropped while the dataset 985 * is still held. The long hold will prevent the dataset from being 986 * destroyed -- the destroy will fail with EBUSY. A long hold can be 987 * obtained by calling dsl_dataset_long_hold(), or by "owning" a dataset 988 * (by calling dsl_{dataset,objset}_{try}own{_obj}). 989 * 990 * Legitimate long-holders (including owners) should be long-running, cancelable 991 * tasks that should cause "zfs destroy" to fail. This includes DMU 992 * consumers (i.e. a ZPL filesystem being mounted or ZVOL being open), 993 * "zfs send", and "zfs diff". There are several other long-holders whose 994 * uses are suboptimal (e.g. "zfs promote", and zil_suspend()). 995 * 996 * The usual formula for long-holding would be: 997 * dsl_pool_hold() 998 * dsl_dataset_hold() 999 * ... perform checks ... 1000 * dsl_dataset_long_hold() 1001 * dsl_pool_rele() 1002 * ... perform long-running task ... 1003 * dsl_dataset_long_rele() 1004 * dsl_dataset_rele() 1005 * 1006 * Note that when the long hold is released, the dataset is still held but 1007 * the pool is not held. The dataset may change arbitrarily during this time 1008 * (e.g. it could be destroyed). Therefore you shouldn't do anything to the 1009 * dataset except release it. 1010 * 1011 * User-initiated operations (e.g. ioctls, zfs_ioc_*()) are either read-only 1012 * or modifying operations. 1013 * 1014 * Modifying operations should generally use dsl_sync_task(). The synctask 1015 * infrastructure enforces proper locking strategy with respect to the 1016 * dp_config_rwlock. See the comment above dsl_sync_task() for details. 1017 * 1018 * Read-only operations will manually hold the pool, then the dataset, obtain 1019 * information from the dataset, then release the pool and dataset. 1020 * dmu_objset_{hold,rele}() are convenience routines that also do the pool 1021 * hold/rele. 1022 */ 1023 1024int 1025dsl_pool_hold(const char *name, void *tag, dsl_pool_t **dp) 1026{ 1027 spa_t *spa; 1028 int error; 1029 1030 error = spa_open(name, &spa, tag); 1031 if (error == 0) { 1032 *dp = spa_get_dsl(spa); 1033 dsl_pool_config_enter(*dp, tag); 1034 } 1035 return (error); 1036} 1037 1038void 1039dsl_pool_rele(dsl_pool_t *dp, void *tag) 1040{ 1041 dsl_pool_config_exit(dp, tag); 1042 spa_close(dp->dp_spa, tag); 1043} 1044 1045void 1046dsl_pool_config_enter(dsl_pool_t *dp, void *tag) 1047{ 1048 /* 1049 * We use a "reentrant" reader-writer lock, but not reentrantly. 1050 * 1051 * The rrwlock can (with the track_all flag) track all reading threads, 1052 * which is very useful for debugging which code path failed to release 1053 * the lock, and for verifying that the *current* thread does hold 1054 * the lock. 1055 * 1056 * (Unlike a rwlock, which knows that N threads hold it for 1057 * read, but not *which* threads, so rw_held(RW_READER) returns TRUE 1058 * if any thread holds it for read, even if this thread doesn't). 1059 */ 1060 ASSERT(!rrw_held(&dp->dp_config_rwlock, RW_READER)); 1061 rrw_enter(&dp->dp_config_rwlock, RW_READER, tag); 1062} 1063 1064void 1065dsl_pool_config_exit(dsl_pool_t *dp, void *tag) 1066{ 1067 rrw_exit(&dp->dp_config_rwlock, tag); 1068} 1069 1070boolean_t 1071dsl_pool_config_held(dsl_pool_t *dp) 1072{ 1073 return (RRW_LOCK_HELD(&dp->dp_config_rwlock)); 1074} 1075