sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_destroy.c

   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/zfs_context.h>
  28 #include <sys/dsl_userhold.h>
  29 #include <sys/dsl_dataset.h>
  30 #include <sys/dsl_synctask.h>
  31 #include <sys/dmu_tx.h>
  32 #include <sys/dsl_pool.h>
  33 #include <sys/dsl_dir.h>
  34 #include <sys/dmu_traverse.h>
  35 #include <sys/dsl_scan.h>
  36 #include <sys/dmu_objset.h>
  37 #include <sys/zap.h>
  38 #include <sys/zfeature.h>
  39 #include <sys/zfs_ioctl.h>
  40 #include <sys/dsl_deleg.h>
  41
  42 typedef struct dmu_snapshots_destroy_arg {
  43         nvlist_t *dsda_snaps;
  44         nvlist_t *dsda_successful_snaps;
  45         boolean_t dsda_defer;
  46         nvlist_t *dsda_errlist;
  47 } dmu_snapshots_destroy_arg_t;
  48
  49 int
  50 dsl_destroy_snapshot_check_impl(dsl_dataset_t *ds, boolean_t defer)
  51 {
  52         if (!dsl_dataset_is_snapshot(ds))
  53                 return (SET_ERROR(EINVAL));
  54
  55         if (dsl_dataset_long_held(ds))
  56                 return (SET_ERROR(EBUSY));
  57
  58         /*
  59          * Only allow deferred destroy on pools that support it.
  60          * NOTE: deferred destroy is only supported on snapshots.
  61          */
  62         if (defer) {
  63                 if (spa_version(ds->ds_dir->dd_pool->dp_spa) <
  64                     SPA_VERSION_USERREFS)
  65                         return (SET_ERROR(ENOTSUP));
  66                 return (0);
  67         }
  68
  69         /*
  70          * If this snapshot has an elevated user reference count,
  71          * we can't destroy it yet.
  72          */
  73         if (ds->ds_userrefs > 0)
  74                 return (SET_ERROR(EBUSY));
  75
  76         /*
  77          * Can't delete a branch point.
  78          */
  79         if (ds->ds_phys->ds_num_children > 1)
  80                 return (SET_ERROR(EEXIST));
  81
  82         return (0);
  83 }
  84
  85 static int
  86 dsl_destroy_snapshot_check(void *arg, dmu_tx_t *tx)
  87 {
  88         dmu_snapshots_destroy_arg_t *dsda = arg;
  89         dsl_pool_t *dp = dmu_tx_pool(tx);
  90         nvpair_t *pair;
  91         int error = 0;
  92
  93         if (!dmu_tx_is_syncing(tx))
  94                 return (0);
  95
  96         for (pair = nvlist_next_nvpair(dsda->dsda_snaps, NULL);
  97             pair != NULL; pair = nvlist_next_nvpair(dsda->dsda_snaps, pair)) {
  98                 dsl_dataset_t *ds;
  99
 100                 error = dsl_dataset_hold(dp, nvpair_name(pair),
 101                     FTAG, &ds);
 102
 103                 /*
 104                  * If the snapshot does not exist, silently ignore it
 105                  * (it's "already destroyed").
 106                  */
 107                 if (error == ENOENT)
 108                         continue;
 109
 110                 if (error == 0) {
 111                         error = dsl_destroy_snapshot_check_impl(ds,
 112                             dsda->dsda_defer);
 113                         dsl_dataset_rele(ds, FTAG);
 114                 }
 115
 116                 if (error == 0) {
 117                         fnvlist_add_boolean(dsda->dsda_successful_snaps,
 118                             nvpair_name(pair));
 119                 } else {
 120                         fnvlist_add_int32(dsda->dsda_errlist,
 121                             nvpair_name(pair), error);
 122                 }
 123         }
 124
 125         pair = nvlist_next_nvpair(dsda->dsda_errlist, NULL);
 126         if (pair != NULL)
 127                 return (fnvpair_value_int32(pair));
 128
 129         return (0);
 130 }
 131
 132 struct process_old_arg {
 133         dsl_dataset_t *ds;
 134         dsl_dataset_t *ds_prev;
 135         boolean_t after_branch_point;
 136         zio_t *pio;
 137         uint64_t used, comp, uncomp;
 138 };
 139
 140 static int
 141 process_old_cb(void *arg, const blkptr_t *bp, dmu_tx_t *tx)
 142 {
 143         struct process_old_arg *poa = arg;
 144         dsl_pool_t *dp = poa->ds->ds_dir->dd_pool;
 145
 146         if (bp->blk_birth <= poa->ds->ds_phys->ds_prev_snap_txg) {
 147                 dsl_deadlist_insert(&poa->ds->ds_deadlist, bp, tx);
 148                 if (poa->ds_prev && !poa->after_branch_point &&
 149                     bp->blk_birth >
 150                     poa->ds_prev->ds_phys->ds_prev_snap_txg) {
 151                         poa->ds_prev->ds_phys->ds_unique_bytes +=
 152                             bp_get_dsize_sync(dp->dp_spa, bp);
 153                 }
 154         } else {
 155                 poa->used += bp_get_dsize_sync(dp->dp_spa, bp);
 156                 poa->comp += BP_GET_PSIZE(bp);
 157                 poa->uncomp += BP_GET_UCSIZE(bp);
 158                 dsl_free_sync(poa->pio, dp, tx->tx_txg, bp);
 159         }
 160         return (0);
 161 }
 162
 163 static void
 164 process_old_deadlist(dsl_dataset_t *ds, dsl_dataset_t *ds_prev,
 165     dsl_dataset_t *ds_next, boolean_t after_branch_point, dmu_tx_t *tx)
 166 {
 167         struct process_old_arg poa = { 0 };
 168         dsl_pool_t *dp = ds->ds_dir->dd_pool;
 169         objset_t *mos = dp->dp_meta_objset;
 170         uint64_t deadlist_obj;
 171
 172         ASSERT(ds->ds_deadlist.dl_oldfmt);
 173         ASSERT(ds_next->ds_deadlist.dl_oldfmt);
 174
 175         poa.ds = ds;
 176         poa.ds_prev = ds_prev;
 177         poa.after_branch_point = after_branch_point;
 178         poa.pio = zio_root(dp->dp_spa, NULL, NULL, ZIO_FLAG_MUSTSUCCEED);
 179         VERIFY0(bpobj_iterate(&ds_next->ds_deadlist.dl_bpobj,
 180             process_old_cb, &poa, tx));
 181         VERIFY0(zio_wait(poa.pio));
 182         ASSERT3U(poa.used, ==, ds->ds_phys->ds_unique_bytes);
 183
 184         /* change snapused */
 185         dsl_dir_diduse_space(ds->ds_dir, DD_USED_SNAP,
 186             -poa.used, -poa.comp, -poa.uncomp, tx);
 187
 188         /* swap next's deadlist to our deadlist */
 189         dsl_deadlist_close(&ds->ds_deadlist);
 190         dsl_deadlist_close(&ds_next->ds_deadlist);
 191         deadlist_obj = ds->ds_phys->ds_deadlist_obj;
 192         ds->ds_phys->ds_deadlist_obj = ds_next->ds_phys->ds_deadlist_obj;
 193         ds_next->ds_phys->ds_deadlist_obj = deadlist_obj;
 194         dsl_deadlist_open(&ds->ds_deadlist, mos, ds->ds_phys->ds_deadlist_obj);
 195         dsl_deadlist_open(&ds_next->ds_deadlist, mos,
 196             ds_next->ds_phys->ds_deadlist_obj);
 197 }
 198
 199 static void
 200 dsl_dataset_remove_clones_key(dsl_dataset_t *ds, uint64_t mintxg, dmu_tx_t *tx)
 201 {
 202         objset_t *mos = ds->ds_dir->dd_pool->dp_meta_objset;
 203         zap_cursor_t zc;
 204         zap_attribute_t za;
 205
 206         /*
 207          * If it is the old version, dd_clones doesn't exist so we can't
 208          * find the clones, but dsl_deadlist_remove_key() is a no-op so it
 209          * doesn't matter.
 210          */
 211         if (ds->ds_dir->dd_phys->dd_clones == 0)
 212                 return;
 213
 214         for (zap_cursor_init(&zc, mos, ds->ds_dir->dd_phys->dd_clones);
 215             zap_cursor_retrieve(&zc, &za) == 0;
 216             zap_cursor_advance(&zc)) {
 217                 dsl_dataset_t *clone;
 218
 219                 VERIFY0(dsl_dataset_hold_obj(ds->ds_dir->dd_pool,
 220                     za.za_first_integer, FTAG, &clone));
 221                 if (clone->ds_dir->dd_origin_txg > mintxg) {
 222                         dsl_deadlist_remove_key(&clone->ds_deadlist,
 223                             mintxg, tx);
 224                         dsl_dataset_remove_clones_key(clone, mintxg, tx);
 225                 }
 226                 dsl_dataset_rele(clone, FTAG);
 227         }
 228         zap_cursor_fini(&zc);
 229 }
 230
 231 void
 232 dsl_destroy_snapshot_sync_impl(dsl_dataset_t *ds, boolean_t defer, dmu_tx_t *tx)
 233 {
 234         int err;
 235         int after_branch_point = FALSE;
 236         dsl_pool_t *dp = ds->ds_dir->dd_pool;
 237         objset_t *mos = dp->dp_meta_objset;
 238         dsl_dataset_t *ds_prev = NULL;
 239         uint64_t obj;
 240
 241         ASSERT(RRW_WRITE_HELD(&dp->dp_config_rwlock));
 242         ASSERT3U(ds->ds_phys->ds_bp.blk_birth, <=, tx->tx_txg);
 243         ASSERT(refcount_is_zero(&ds->ds_longholds));
 244
 245         if (defer &&
 246             (ds->ds_userrefs > 0 || ds->ds_phys->ds_num_children > 1)) {
 247                 ASSERT(spa_version(dp->dp_spa) >= SPA_VERSION_USERREFS);
 248                 dmu_buf_will_dirty(ds->ds_dbuf, tx);
 249                 ds->ds_phys->ds_flags |= DS_FLAG_DEFER_DESTROY;
 250                 spa_history_log_internal_ds(ds, "defer_destroy", tx, "");
 251                 return;
 252         }
 253
 254         ASSERT3U(ds->ds_phys->ds_num_children, <=, 1);
 255
 256         /* We need to log before removing it from the namespace. */
 257         spa_history_log_internal_ds(ds, "destroy", tx, "");
 258
 259         dsl_scan_ds_destroyed(ds, tx);
 260
 261         obj = ds->ds_object;
 262
 263         if (ds->ds_phys->ds_prev_snap_obj != 0) {
 264                 ASSERT3P(ds->ds_prev, ==, NULL);
 265                 VERIFY0(dsl_dataset_hold_obj(dp,
 266                     ds->ds_phys->ds_prev_snap_obj, FTAG, &ds_prev));
 267                 after_branch_point =
 268                     (ds_prev->ds_phys->ds_next_snap_obj != obj);
 269
 270                 dmu_buf_will_dirty(ds_prev->ds_dbuf, tx);
 271                 if (after_branch_point &&
 272                     ds_prev->ds_phys->ds_next_clones_obj != 0) {
 273                         dsl_dataset_remove_from_next_clones(ds_prev, obj, tx);
 274                         if (ds->ds_phys->ds_next_snap_obj != 0) {
 275                                 VERIFY0(zap_add_int(mos,
 276                                     ds_prev->ds_phys->ds_next_clones_obj,
 277                                     ds->ds_phys->ds_next_snap_obj, tx));
 278                         }
 279                 }
 280                 if (!after_branch_point) {
 281                         ds_prev->ds_phys->ds_next_snap_obj =
 282                             ds->ds_phys->ds_next_snap_obj;
 283                 }
 284         }
 285
 286         dsl_dataset_t *ds_next;
 287         uint64_t old_unique;
 288         uint64_t used = 0, comp = 0, uncomp = 0;
 289
 290         VERIFY0(dsl_dataset_hold_obj(dp,
 291             ds->ds_phys->ds_next_snap_obj, FTAG, &ds_next));
 292         ASSERT3U(ds_next->ds_phys->ds_prev_snap_obj, ==, obj);
 293
 294         old_unique = ds_next->ds_phys->ds_unique_bytes;
 295
 296         dmu_buf_will_dirty(ds_next->ds_dbuf, tx);
 297         ds_next->ds_phys->ds_prev_snap_obj =
 298             ds->ds_phys->ds_prev_snap_obj;
 299         ds_next->ds_phys->ds_prev_snap_txg =
 300             ds->ds_phys->ds_prev_snap_txg;
 301         ASSERT3U(ds->ds_phys->ds_prev_snap_txg, ==,
 302             ds_prev ? ds_prev->ds_phys->ds_creation_txg : 0);
 303
 304         if (ds_next->ds_deadlist.dl_oldfmt) {
 305                 process_old_deadlist(ds, ds_prev, ds_next,
 306                     after_branch_point, tx);
 307         } else {
 308                 /* Adjust prev's unique space. */
 309                 if (ds_prev && !after_branch_point) {
 310                         dsl_deadlist_space_range(&ds_next->ds_deadlist,
 311                             ds_prev->ds_phys->ds_prev_snap_txg,
 312                             ds->ds_phys->ds_prev_snap_txg,
 313                             &used, &comp, &uncomp);
 314                         ds_prev->ds_phys->ds_unique_bytes += used;
 315                 }
 316
 317                 /* Adjust snapused. */
 318                 dsl_deadlist_space_range(&ds_next->ds_deadlist,
 319                     ds->ds_phys->ds_prev_snap_txg, UINT64_MAX,
 320                     &used, &comp, &uncomp);
 321                 dsl_dir_diduse_space(ds->ds_dir, DD_USED_SNAP,
 322                     -used, -comp, -uncomp, tx);
 323
 324                 /* Move blocks to be freed to pool's free list. */
 325                 dsl_deadlist_move_bpobj(&ds_next->ds_deadlist,
 326                     &dp->dp_free_bpobj, ds->ds_phys->ds_prev_snap_txg,
 327                     tx);
 328                 dsl_dir_diduse_space(tx->tx_pool->dp_free_dir,
 329                     DD_USED_HEAD, used, comp, uncomp, tx);
 330
 331                 /* Merge our deadlist into next's and free it. */
 332                 dsl_deadlist_merge(&ds_next->ds_deadlist,
 333                     ds->ds_phys->ds_deadlist_obj, tx);
 334         }
 335         dsl_deadlist_close(&ds->ds_deadlist);
 336         dsl_deadlist_free(mos, ds->ds_phys->ds_deadlist_obj, tx);
 337         dmu_buf_will_dirty(ds->ds_dbuf, tx);
 338         ds->ds_phys->ds_deadlist_obj = 0;
 339
 340         /* Collapse range in clone heads */
 341         dsl_dataset_remove_clones_key(ds,
 342             ds->ds_phys->ds_creation_txg, tx);
 343
 344         if (dsl_dataset_is_snapshot(ds_next)) {
 345                 dsl_dataset_t *ds_nextnext;
 346
 347                 /*
 348                  * Update next's unique to include blocks which
 349                  * were previously shared by only this snapshot
 350                  * and it.  Those blocks will be born after the
 351                  * prev snap and before this snap, and will have
 352                  * died after the next snap and before the one
 353                  * after that (ie. be on the snap after next's
 354                  * deadlist).
 355                  */
 356                 VERIFY0(dsl_dataset_hold_obj(dp,
 357                     ds_next->ds_phys->ds_next_snap_obj, FTAG, &ds_nextnext));
 358                 dsl_deadlist_space_range(&ds_nextnext->ds_deadlist,
 359                     ds->ds_phys->ds_prev_snap_txg,
 360                     ds->ds_phys->ds_creation_txg,
 361                     &used, &comp, &uncomp);
 362                 ds_next->ds_phys->ds_unique_bytes += used;
 363                 dsl_dataset_rele(ds_nextnext, FTAG);
 364                 ASSERT3P(ds_next->ds_prev, ==, NULL);
 365
 366                 /* Collapse range in this head. */
 367                 dsl_dataset_t *hds;
 368                 VERIFY0(dsl_dataset_hold_obj(dp,
 369                     ds->ds_dir->dd_phys->dd_head_dataset_obj, FTAG, &hds));
 370                 dsl_deadlist_remove_key(&hds->ds_deadlist,
 371                     ds->ds_phys->ds_creation_txg, tx);
 372                 dsl_dataset_rele(hds, FTAG);
 373
 374         } else {
 375                 ASSERT3P(ds_next->ds_prev, ==, ds);
 376                 dsl_dataset_rele(ds_next->ds_prev, ds_next);
 377                 ds_next->ds_prev = NULL;
 378                 if (ds_prev) {
 379                         VERIFY0(dsl_dataset_hold_obj(dp,
 380                             ds->ds_phys->ds_prev_snap_obj,
 381                             ds_next, &ds_next->ds_prev));
 382                 }
 383
 384                 dsl_dataset_recalc_head_uniq(ds_next);
 385
 386                 /*
 387                  * Reduce the amount of our unconsumed refreservation
 388                  * being charged to our parent by the amount of
 389                  * new unique data we have gained.
 390                  */
 391                 if (old_unique < ds_next->ds_reserved) {
 392                         int64_t mrsdelta;
 393                         uint64_t new_unique =
 394                             ds_next->ds_phys->ds_unique_bytes;
 395
 396                         ASSERT(old_unique <= new_unique);
 397                         mrsdelta = MIN(new_unique - old_unique,
 398                             ds_next->ds_reserved - old_unique);
 399                         dsl_dir_diduse_space(ds->ds_dir,
 400                             DD_USED_REFRSRV, -mrsdelta, 0, 0, tx);
 401                 }
 402         }
 403         dsl_dataset_rele(ds_next, FTAG);
 404
 405         /*
 406          * This must be done after the dsl_traverse(), because it will
 407          * re-open the objset.
 408          */
 409         if (ds->ds_objset) {
 410                 dmu_objset_evict(ds->ds_objset);
 411                 ds->ds_objset = NULL;
 412         }
 413
 414         /* remove from snapshot namespace */
 415         dsl_dataset_t *ds_head;
 416         ASSERT(ds->ds_phys->ds_snapnames_zapobj == 0);
 417         VERIFY0(dsl_dataset_hold_obj(dp,
 418             ds->ds_dir->dd_phys->dd_head_dataset_obj, FTAG, &ds_head));
 419         VERIFY0(dsl_dataset_get_snapname(ds));
 420 #ifdef ZFS_DEBUG
 421         {
 422                 uint64_t val;
 423
 424                 err = dsl_dataset_snap_lookup(ds_head,
 425                     ds->ds_snapname, &val);
 426                 ASSERT0(err);
 427                 ASSERT3U(val, ==, obj);
 428         }
 429 #endif
 430         VERIFY0(dsl_dataset_snap_remove(ds_head, ds->ds_snapname, tx));
 431         dsl_dataset_rele(ds_head, FTAG);
 432
 433         if (ds_prev != NULL)
 434                 dsl_dataset_rele(ds_prev, FTAG);
 435
 436         spa_prop_clear_bootfs(dp->dp_spa, ds->ds_object, tx);
 437
 438         if (ds->ds_phys->ds_next_clones_obj != 0) {
 439                 uint64_t count;
 440                 ASSERT0(zap_count(mos,
 441                     ds->ds_phys->ds_next_clones_obj, &count) && count == 0);
 442                 VERIFY0(dmu_object_free(mos,
 443                     ds->ds_phys->ds_next_clones_obj, tx));
 444         }
 445         if (ds->ds_phys->ds_props_obj != 0)
 446                 VERIFY0(zap_destroy(mos, ds->ds_phys->ds_props_obj, tx));
 447         if (ds->ds_phys->ds_userrefs_obj != 0)
 448                 VERIFY0(zap_destroy(mos, ds->ds_phys->ds_userrefs_obj, tx));
 449         dsl_dir_rele(ds->ds_dir, ds);
 450         ds->ds_dir = NULL;
 451         VERIFY0(dmu_object_free(mos, obj, tx));
 452 }
 453
 454 static void
 455 dsl_destroy_snapshot_sync(void *arg, dmu_tx_t *tx)
 456 {
 457         dmu_snapshots_destroy_arg_t *dsda = arg;
 458         dsl_pool_t *dp = dmu_tx_pool(tx);
 459         nvpair_t *pair;
 460
 461         for (pair = nvlist_next_nvpair(dsda->dsda_successful_snaps, NULL);
 462             pair != NULL;
 463             pair = nvlist_next_nvpair(dsda->dsda_successful_snaps, pair)) {
 464                 dsl_dataset_t *ds;
 465
 466                 VERIFY0(dsl_dataset_hold(dp, nvpair_name(pair), FTAG, &ds));
 467
 468                 dsl_destroy_snapshot_sync_impl(ds, dsda->dsda_defer, tx);
 469                 dsl_dataset_rele(ds, FTAG);
 470         }
 471 }
 472
 473 /*
 474  * The semantics of this function are described in the comment above
 475  * lzc_destroy_snaps().  To summarize:
 476  *
 477  * The snapshots must all be in the same pool.
 478  *
 479  * Snapshots that don't exist will be silently ignored (considered to be
 480  * "already deleted").
 481  *
 482  * On success, all snaps will be destroyed and this will return 0.
 483  * On failure, no snaps will be destroyed, the errlist will be filled in,
 484  * and this will return an errno.
 485  */
 486 int
 487 dsl_destroy_snapshots_nvl(nvlist_t *snaps, boolean_t defer,
 488     nvlist_t *errlist)
 489 {
 490         dmu_snapshots_destroy_arg_t dsda;
 491         int error;
 492         nvpair_t *pair;
 493
 494         pair = nvlist_next_nvpair(snaps, NULL);
 495         if (pair == NULL)
 496                 return (0);
 497
 498         dsda.dsda_snaps = snaps;
 499         dsda.dsda_successful_snaps = fnvlist_alloc();
 500         dsda.dsda_defer = defer;
 501         dsda.dsda_errlist = errlist;
 502
 503         error = dsl_sync_task(nvpair_name(pair),
 504             dsl_destroy_snapshot_check, dsl_destroy_snapshot_sync,
 505             &dsda, 0);
 506         fnvlist_free(dsda.dsda_successful_snaps);
 507
 508         return (error);
 509 }
 510
 511 int
 512 dsl_destroy_snapshot(const char *name, boolean_t defer)
 513 {
 514         int error;
 515         nvlist_t *nvl = fnvlist_alloc();
 516         nvlist_t *errlist = fnvlist_alloc();
 517
 518         fnvlist_add_boolean(nvl, name);
 519         error = dsl_destroy_snapshots_nvl(nvl, defer, errlist);
 520         fnvlist_free(errlist);
 521         fnvlist_free(nvl);
 522         return (error);
 523 }
 524
 525 struct killarg {
 526         dsl_dataset_t *ds;
 527         dmu_tx_t *tx;
 528 };
 529
 530 /* ARGSUSED */
 531 static int
 532 kill_blkptr(spa_t *spa, zilog_t *zilog, const blkptr_t *bp,
 533     const zbookmark_t *zb, const dnode_phys_t *dnp, void *arg)
 534 {
 535         struct killarg *ka = arg;
 536         dmu_tx_t *tx = ka->tx;
 537
 538         if (bp == NULL)
 539                 return (0);
 540
 541         if (zb->zb_level == ZB_ZIL_LEVEL) {
 542                 ASSERT(zilog != NULL);
 543                 /*
 544                  * It's a block in the intent log.  It has no
 545                  * accounting, so just free it.
 546                  */
 547                 dsl_free(ka->tx->tx_pool, ka->tx->tx_txg, bp);
 548         } else {
 549                 ASSERT(zilog == NULL);
 550                 ASSERT3U(bp->blk_birth, >, ka->ds->ds_phys->ds_prev_snap_txg);
 551                 (void) dsl_dataset_block_kill(ka->ds, bp, tx, B_FALSE);
 552         }
 553
 554         return (0);
 555 }
 556
 557 static void
 558 old_synchronous_dataset_destroy(dsl_dataset_t *ds, dmu_tx_t *tx)
 559 {
 560         struct killarg ka;
 561
 562         /*
 563          * Free everything that we point to (that's born after
 564          * the previous snapshot, if we are a clone)
 565          *
 566          * NB: this should be very quick, because we already
 567          * freed all the objects in open context.
 568          */
 569         ka.ds = ds;
 570         ka.tx = tx;
 571         VERIFY0(traverse_dataset(ds,
 572             ds->ds_phys->ds_prev_snap_txg, TRAVERSE_POST,
 573             kill_blkptr, &ka));
 574         ASSERT(!DS_UNIQUE_IS_ACCURATE(ds) || ds->ds_phys->ds_unique_bytes == 0);
 575 }
 576
 577 typedef struct dsl_destroy_head_arg {
 578         const char *ddha_name;
 579 } dsl_destroy_head_arg_t;
 580
 581 int
 582 dsl_destroy_head_check_impl(dsl_dataset_t *ds, int expected_holds)
 583 {
 584         int error;
 585         uint64_t count;
 586         objset_t *mos;
 587
 588         if (dsl_dataset_is_snapshot(ds))
 589                 return (SET_ERROR(EINVAL));
 590
 591         if (refcount_count(&ds->ds_longholds) != expected_holds)
 592                 return (SET_ERROR(EBUSY));
 593
 594         mos = ds->ds_dir->dd_pool->dp_meta_objset;
 595
 596         /*
 597          * Can't delete a head dataset if there are snapshots of it.
 598          * (Except if the only snapshots are from the branch we cloned
 599          * from.)
 600          */
 601         if (ds->ds_prev != NULL &&
 602             ds->ds_prev->ds_phys->ds_next_snap_obj == ds->ds_object)
 603                 return (SET_ERROR(EBUSY));
 604
 605         /*
 606          * Can't delete if there are children of this fs.
 607          */
 608         error = zap_count(mos,
 609             ds->ds_dir->dd_phys->dd_child_dir_zapobj, &count);
 610         if (error != 0)
 611                 return (error);
 612         if (count != 0)
 613                 return (SET_ERROR(EEXIST));
 614
 615         if (dsl_dir_is_clone(ds->ds_dir) && DS_IS_DEFER_DESTROY(ds->ds_prev) &&
 616             ds->ds_prev->ds_phys->ds_num_children == 2 &&
 617             ds->ds_prev->ds_userrefs == 0) {
 618                 /* We need to remove the origin snapshot as well. */
 619                 if (!refcount_is_zero(&ds->ds_prev->ds_longholds))
 620                         return (SET_ERROR(EBUSY));
 621         }
 622         return (0);
 623 }
 624
 625 static int
 626 dsl_destroy_head_check(void *arg, dmu_tx_t *tx)
 627 {
 628         dsl_destroy_head_arg_t *ddha = arg;
 629         dsl_pool_t *dp = dmu_tx_pool(tx);
 630         dsl_dataset_t *ds;
 631         int error;
 632
 633         error = dsl_dataset_hold(dp, ddha->ddha_name, FTAG, &ds);
 634         if (error != 0)
 635                 return (error);
 636
 637         error = dsl_destroy_head_check_impl(ds, 0);
 638         dsl_dataset_rele(ds, FTAG);
 639         return (error);
 640 }
 641
 642 static void
 643 dsl_dir_destroy_sync(uint64_t ddobj, dmu_tx_t *tx)
 644 {
 645         dsl_dir_t *dd;
 646         dsl_pool_t *dp = dmu_tx_pool(tx);
 647         objset_t *mos = dp->dp_meta_objset;
 648         dd_used_t t;
 649
 650         ASSERT(RRW_WRITE_HELD(&dmu_tx_pool(tx)->dp_config_rwlock));
 651
 652         VERIFY0(dsl_dir_hold_obj(dp, ddobj, NULL, FTAG, &dd));
 653
 654         ASSERT0(dd->dd_phys->dd_head_dataset_obj);
 655
 656         /*
 657          * Remove our reservation. The impl() routine avoids setting the
 658          * actual property, which would require the (already destroyed) ds.
 659          */
 660         dsl_dir_set_reservation_sync_impl(dd, 0, tx);
 661
 662         ASSERT0(dd->dd_phys->dd_used_bytes);
 663         ASSERT0(dd->dd_phys->dd_reserved);
 664         for (t = 0; t < DD_USED_NUM; t++)
 665                 ASSERT0(dd->dd_phys->dd_used_breakdown[t]);
 666
 667         VERIFY0(zap_destroy(mos, dd->dd_phys->dd_child_dir_zapobj, tx));
 668         VERIFY0(zap_destroy(mos, dd->dd_phys->dd_props_zapobj, tx));
 669         VERIFY0(dsl_deleg_destroy(mos, dd->dd_phys->dd_deleg_zapobj, tx));
 670         VERIFY0(zap_remove(mos,
 671             dd->dd_parent->dd_phys->dd_child_dir_zapobj, dd->dd_myname, tx));
 672
 673         dsl_dir_rele(dd, FTAG);
 674         VERIFY0(dmu_object_free(mos, ddobj, tx));
 675 }
 676
 677 void
 678 dsl_destroy_head_sync_impl(dsl_dataset_t *ds, dmu_tx_t *tx)
 679 {
 680         dsl_pool_t *dp = dmu_tx_pool(tx);
 681         objset_t *mos = dp->dp_meta_objset;
 682         uint64_t obj, ddobj, prevobj = 0;
 683         boolean_t rmorigin;
 684
 685         ASSERT3U(ds->ds_phys->ds_num_children, <=, 1);
 686         ASSERT(ds->ds_prev == NULL ||
 687             ds->ds_prev->ds_phys->ds_next_snap_obj != ds->ds_object);
 688         ASSERT3U(ds->ds_phys->ds_bp.blk_birth, <=, tx->tx_txg);
 689         ASSERT(RRW_WRITE_HELD(&dp->dp_config_rwlock));
 690
 691         /* We need to log before removing it from the namespace. */
 692         spa_history_log_internal_ds(ds, "destroy", tx, "");
 693
 694         rmorigin = (dsl_dir_is_clone(ds->ds_dir) &&
 695             DS_IS_DEFER_DESTROY(ds->ds_prev) &&
 696             ds->ds_prev->ds_phys->ds_num_children == 2 &&
 697             ds->ds_prev->ds_userrefs == 0);
 698
 699         /* Remove our reservation */
 700         if (ds->ds_reserved != 0) {
 701                 dsl_dataset_set_refreservation_sync_impl(ds,
 702                     (ZPROP_SRC_NONE | ZPROP_SRC_LOCAL | ZPROP_SRC_RECEIVED),
 703                     0, tx);
 704                 ASSERT0(ds->ds_reserved);
 705         }
 706
 707         dsl_scan_ds_destroyed(ds, tx);
 708
 709         obj = ds->ds_object;
 710
 711         if (ds->ds_phys->ds_prev_snap_obj != 0) {
 712                 /* This is a clone */
 713                 ASSERT(ds->ds_prev != NULL);
 714                 ASSERT3U(ds->ds_prev->ds_phys->ds_next_snap_obj, !=, obj);
 715                 ASSERT0(ds->ds_phys->ds_next_snap_obj);
 716
 717                 dmu_buf_will_dirty(ds->ds_prev->ds_dbuf, tx);
 718                 if (ds->ds_prev->ds_phys->ds_next_clones_obj != 0) {
 719                         dsl_dataset_remove_from_next_clones(ds->ds_prev,
 720                             obj, tx);
 721                 }
 722
 723                 ASSERT3U(ds->ds_prev->ds_phys->ds_num_children, >, 1);
 724                 ds->ds_prev->ds_phys->ds_num_children--;
 725         }
 726
 727         zfeature_info_t *async_destroy =
 728             &spa_feature_table[SPA_FEATURE_ASYNC_DESTROY];
 729         objset_t *os;
 730
 731         /*
 732          * Destroy the deadlist.  Unless it's a clone, the
 733          * deadlist should be empty.  (If it's a clone, it's
 734          * safe to ignore the deadlist contents.)
 735          */
 736         dsl_deadlist_close(&ds->ds_deadlist);
 737         dsl_deadlist_free(mos, ds->ds_phys->ds_deadlist_obj, tx);
 738         dmu_buf_will_dirty(ds->ds_dbuf, tx);
 739         ds->ds_phys->ds_deadlist_obj = 0;
 740
 741         VERIFY0(dmu_objset_from_ds(ds, &os));
 742
 743         if (!spa_feature_is_enabled(dp->dp_spa, async_destroy)) {
 744                 old_synchronous_dataset_destroy(ds, tx);
 745         } else {
 746                 /*
 747                  * Move the bptree into the pool's list of trees to
 748                  * clean up and update space accounting information.
 749                  */
 750                 uint64_t used, comp, uncomp;
 751
 752                 zil_destroy_sync(dmu_objset_zil(os), tx);
 753
 754                 if (!spa_feature_is_active(dp->dp_spa, async_destroy)) {
 755                         dsl_scan_t *scn = dp->dp_scan;
 756
 757                         spa_feature_incr(dp->dp_spa, async_destroy, tx);
 758                         dp->dp_bptree_obj = bptree_alloc(mos, tx);
 759                         VERIFY0(zap_add(mos,
 760                             DMU_POOL_DIRECTORY_OBJECT,
 761                             DMU_POOL_BPTREE_OBJ, sizeof (uint64_t), 1,
 762                             &dp->dp_bptree_obj, tx));
 763                         ASSERT(!scn->scn_async_destroying);
 764                         scn->scn_async_destroying = B_TRUE;
 765                 }
 766
 767                 used = ds->ds_dir->dd_phys->dd_used_bytes;
 768                 comp = ds->ds_dir->dd_phys->dd_compressed_bytes;
 769                 uncomp = ds->ds_dir->dd_phys->dd_uncompressed_bytes;
 770
 771                 ASSERT(!DS_UNIQUE_IS_ACCURATE(ds) ||
 772                     ds->ds_phys->ds_unique_bytes == used);
 773
 774                 bptree_add(mos, dp->dp_bptree_obj,
 775                     &ds->ds_phys->ds_bp, ds->ds_phys->ds_prev_snap_txg,
 776                     used, comp, uncomp, tx);
 777                 dsl_dir_diduse_space(ds->ds_dir, DD_USED_HEAD,
 778                     -used, -comp, -uncomp, tx);
 779                 dsl_dir_diduse_space(dp->dp_free_dir, DD_USED_HEAD,
 780                     used, comp, uncomp, tx);
 781         }
 782
 783         if (ds->ds_prev != NULL) {
 784                 if (spa_version(dp->dp_spa) >= SPA_VERSION_DIR_CLONES) {
 785                         VERIFY0(zap_remove_int(mos,
 786                             ds->ds_prev->ds_dir->dd_phys->dd_clones,
 787                             ds->ds_object, tx));
 788                 }
 789                 prevobj = ds->ds_prev->ds_object;
 790                 dsl_dataset_rele(ds->ds_prev, ds);
 791                 ds->ds_prev = NULL;
 792         }
 793
 794         /*
 795          * This must be done after the dsl_traverse(), because it will
 796          * re-open the objset.
 797          */
 798         if (ds->ds_objset) {
 799                 dmu_objset_evict(ds->ds_objset);
 800                 ds->ds_objset = NULL;
 801         }
 802
 803         /* Erase the link in the dir */
 804         dmu_buf_will_dirty(ds->ds_dir->dd_dbuf, tx);
 805         ds->ds_dir->dd_phys->dd_head_dataset_obj = 0;
 806         ddobj = ds->ds_dir->dd_object;
 807         ASSERT(ds->ds_phys->ds_snapnames_zapobj != 0);
 808         VERIFY0(zap_destroy(mos, ds->ds_phys->ds_snapnames_zapobj, tx));
 809
 810         spa_prop_clear_bootfs(dp->dp_spa, ds->ds_object, tx);
 811
 812         ASSERT0(ds->ds_phys->ds_next_clones_obj);
 813         ASSERT0(ds->ds_phys->ds_props_obj);
 814         ASSERT0(ds->ds_phys->ds_userrefs_obj);
 815         dsl_dir_rele(ds->ds_dir, ds);
 816         ds->ds_dir = NULL;
 817         VERIFY0(dmu_object_free(mos, obj, tx));
 818
 819         dsl_dir_destroy_sync(ddobj, tx);
 820
 821         if (rmorigin) {
 822                 dsl_dataset_t *prev;
 823                 VERIFY0(dsl_dataset_hold_obj(dp, prevobj, FTAG, &prev));
 824                 dsl_destroy_snapshot_sync_impl(prev, B_FALSE, tx);
 825                 dsl_dataset_rele(prev, FTAG);
 826         }
 827 }
 828
 829 static void
 830 dsl_destroy_head_sync(void *arg, dmu_tx_t *tx)
 831 {
 832         dsl_destroy_head_arg_t *ddha = arg;
 833         dsl_pool_t *dp = dmu_tx_pool(tx);
 834         dsl_dataset_t *ds;
 835
 836         VERIFY0(dsl_dataset_hold(dp, ddha->ddha_name, FTAG, &ds));
 837         dsl_destroy_head_sync_impl(ds, tx);
 838         dsl_dataset_rele(ds, FTAG);
 839 }
 840
 841 static void
 842 dsl_destroy_head_begin_sync(void *arg, dmu_tx_t *tx)
 843 {
 844         dsl_destroy_head_arg_t *ddha = arg;
 845         dsl_pool_t *dp = dmu_tx_pool(tx);
 846         dsl_dataset_t *ds;
 847
 848         VERIFY0(dsl_dataset_hold(dp, ddha->ddha_name, FTAG, &ds));
 849
 850         /* Mark it as inconsistent on-disk, in case we crash */
 851         dmu_buf_will_dirty(ds->ds_dbuf, tx);
 852         ds->ds_phys->ds_flags |= DS_FLAG_INCONSISTENT;
 853
 854         spa_history_log_internal_ds(ds, "destroy begin", tx, "");
 855         dsl_dataset_rele(ds, FTAG);
 856 }
 857
 858 int
 859 dsl_destroy_head(const char *name)
 860 {
 861         dsl_destroy_head_arg_t ddha;
 862         int error;
 863         spa_t *spa;
 864         boolean_t isenabled;
 865
 866 #ifdef _KERNEL
 867         zfs_destroy_unmount_origin(name);
 868 #endif
 869
 870         error = spa_open(name, &spa, FTAG);
 871         if (error != 0)
 872                 return (error);
 873         isenabled = spa_feature_is_enabled(spa,
 874             &spa_feature_table[SPA_FEATURE_ASYNC_DESTROY]);
 875         spa_close(spa, FTAG);
 876
 877         ddha.ddha_name = name;
 878
 879         if (!isenabled) {
 880                 objset_t *os;
 881
 882                 error = dsl_sync_task(name, dsl_destroy_head_check,
 883                     dsl_destroy_head_begin_sync, &ddha, 0);
 884                 if (error != 0)
 885                         return (error);
 886
 887                 /*
 888                  * Head deletion is processed in one txg on old pools;
 889                  * remove the objects from open context so that the txg sync
 890                  * is not too long.
 891                  */
 892                 error = dmu_objset_own(name, DMU_OST_ANY, B_FALSE, FTAG, &os);
 893                 if (error == 0) {
 894                         uint64_t prev_snap_txg =
 895                             dmu_objset_ds(os)->ds_phys->ds_prev_snap_txg;
 896                         for (uint64_t obj = 0; error == 0;
 897                             error = dmu_object_next(os, &obj, FALSE,
 898                             prev_snap_txg))
 899                                 (void) dmu_free_long_object(os, obj);
 900                         /* sync out all frees */
 901                         txg_wait_synced(dmu_objset_pool(os), 0);
 902                         dmu_objset_disown(os, FTAG);
 903                 }
 904         }
 905
 906         return (dsl_sync_task(name, dsl_destroy_head_check,
 907             dsl_destroy_head_sync, &ddha, 0));
 908 }
 909
 910 /*
 911  * Note, this function is used as the callback for dmu_objset_find().  We
 912  * always return 0 so that we will continue to find and process
 913  * inconsistent datasets, even if we encounter an error trying to
 914  * process one of them.
 915  */
 916 /* ARGSUSED */
 917 int
 918 dsl_destroy_inconsistent(const char *dsname, void *arg)
 919 {
 920         objset_t *os;
 921
 922         if (dmu_objset_hold(dsname, FTAG, &os) == 0) {
 923                 boolean_t inconsistent = DS_IS_INCONSISTENT(dmu_objset_ds(os));
 924                 dmu_objset_rele(os, FTAG);
 925                 if (inconsistent)
 926                         (void) dsl_destroy_head(dsname);
 927         }
 928         return (0);
 929 }