sys/contrib/openzfs/module/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) 2012, 2018 by Delphix. All rights reserved.
  24  * Copyright (c) 2013 Steven Hartland. All rights reserved.
  25  * Copyright (c) 2013 by Joyent, Inc. All rights reserved.
  26  * Copyright (c) 2016 Actifio, Inc. All rights reserved.
  27  */
  28
  29 #include <sys/zfs_context.h>
  30 #include <sys/dsl_userhold.h>
  31 #include <sys/dsl_dataset.h>
  32 #include <sys/dsl_synctask.h>
  33 #include <sys/dsl_destroy.h>
  34 #include <sys/dsl_bookmark.h>
  35 #include <sys/dmu_tx.h>
  36 #include <sys/dsl_pool.h>
  37 #include <sys/dsl_dir.h>
  38 #include <sys/dmu_traverse.h>
  39 #include <sys/dsl_scan.h>
  40 #include <sys/dmu_objset.h>
  41 #include <sys/zap.h>
  42 #include <sys/zfeature.h>
  43 #include <sys/zfs_ioctl.h>
  44 #include <sys/dsl_deleg.h>
  45 #include <sys/dmu_impl.h>
  46 #include <sys/zvol.h>
  47 #include <sys/zcp.h>
  48 #include <sys/dsl_deadlist.h>
  49 #include <sys/zthr.h>
  50 #include <sys/spa_impl.h>
  51
  52 int
  53 dsl_destroy_snapshot_check_impl(dsl_dataset_t *ds, boolean_t defer)
  54 {
  55         if (!ds->ds_is_snapshot)
  56                 return (SET_ERROR(EINVAL));
  57
  58         if (dsl_dataset_long_held(ds))
  59                 return (SET_ERROR(EBUSY));
  60
  61         /*
  62          * Only allow deferred destroy on pools that support it.
  63          * NOTE: deferred destroy is only supported on snapshots.
  64          */
  65         if (defer) {
  66                 if (spa_version(ds->ds_dir->dd_pool->dp_spa) <
  67                     SPA_VERSION_USERREFS)
  68                         return (SET_ERROR(ENOTSUP));
  69                 return (0);
  70         }
  71
  72         /*
  73          * If this snapshot has an elevated user reference count,
  74          * we can't destroy it yet.
  75          */
  76         if (ds->ds_userrefs > 0)
  77                 return (SET_ERROR(EBUSY));
  78
  79         /*
  80          * Can't delete a branch point.
  81          */
  82         if (dsl_dataset_phys(ds)->ds_num_children > 1)
  83                 return (SET_ERROR(EEXIST));
  84
  85         return (0);
  86 }
  87
  88 int
  89 dsl_destroy_snapshot_check(void *arg, dmu_tx_t *tx)
  90 {
  91         dsl_destroy_snapshot_arg_t *ddsa = arg;
  92         const char *dsname = ddsa->ddsa_name;
  93         boolean_t defer = ddsa->ddsa_defer;
  94
  95         dsl_pool_t *dp = dmu_tx_pool(tx);
  96         int error = 0;
  97         dsl_dataset_t *ds;
  98
  99         error = dsl_dataset_hold(dp, dsname, FTAG, &ds);
 100
 101         /*
 102          * If the snapshot does not exist, silently ignore it, and
 103          * dsl_destroy_snapshot_sync() will be a no-op
 104          * (it's "already destroyed").
 105          */
 106         if (error == ENOENT)
 107                 return (0);
 108
 109         if (error == 0) {
 110                 error = dsl_destroy_snapshot_check_impl(ds, defer);
 111                 dsl_dataset_rele(ds, FTAG);
 112         }
 113
 114         return (error);
 115 }
 116
 117 struct process_old_arg {
 118         dsl_dataset_t *ds;
 119         dsl_dataset_t *ds_prev;
 120         boolean_t after_branch_point;
 121         zio_t *pio;
 122         uint64_t used, comp, uncomp;
 123 };
 124
 125 static int
 126 process_old_cb(void *arg, const blkptr_t *bp, boolean_t bp_freed, dmu_tx_t *tx)
 127 {
 128         struct process_old_arg *poa = arg;
 129         dsl_pool_t *dp = poa->ds->ds_dir->dd_pool;
 130
 131         ASSERT(!BP_IS_HOLE(bp));
 132
 133         if (bp->blk_birth <= dsl_dataset_phys(poa->ds)->ds_prev_snap_txg) {
 134                 dsl_deadlist_insert(&poa->ds->ds_deadlist, bp, bp_freed, tx);
 135                 if (poa->ds_prev && !poa->after_branch_point &&
 136                     bp->blk_birth >
 137                     dsl_dataset_phys(poa->ds_prev)->ds_prev_snap_txg) {
 138                         dsl_dataset_phys(poa->ds_prev)->ds_unique_bytes +=
 139                             bp_get_dsize_sync(dp->dp_spa, bp);
 140                 }
 141         } else {
 142                 poa->used += bp_get_dsize_sync(dp->dp_spa, bp);
 143                 poa->comp += BP_GET_PSIZE(bp);
 144                 poa->uncomp += BP_GET_UCSIZE(bp);
 145                 dsl_free_sync(poa->pio, dp, tx->tx_txg, bp);
 146         }
 147         return (0);
 148 }
 149
 150 static void
 151 process_old_deadlist(dsl_dataset_t *ds, dsl_dataset_t *ds_prev,
 152     dsl_dataset_t *ds_next, boolean_t after_branch_point, dmu_tx_t *tx)
 153 {
 154         struct process_old_arg poa = { 0 };
 155         dsl_pool_t *dp = ds->ds_dir->dd_pool;
 156         objset_t *mos = dp->dp_meta_objset;
 157         uint64_t deadlist_obj;
 158
 159         ASSERT(ds->ds_deadlist.dl_oldfmt);
 160         ASSERT(ds_next->ds_deadlist.dl_oldfmt);
 161
 162         poa.ds = ds;
 163         poa.ds_prev = ds_prev;
 164         poa.after_branch_point = after_branch_point;
 165         poa.pio = zio_root(dp->dp_spa, NULL, NULL, ZIO_FLAG_MUSTSUCCEED);
 166         VERIFY0(bpobj_iterate(&ds_next->ds_deadlist.dl_bpobj,
 167             process_old_cb, &poa, tx));
 168         VERIFY0(zio_wait(poa.pio));
 169         ASSERT3U(poa.used, ==, dsl_dataset_phys(ds)->ds_unique_bytes);
 170
 171         /* change snapused */
 172         dsl_dir_diduse_space(ds->ds_dir, DD_USED_SNAP,
 173             -poa.used, -poa.comp, -poa.uncomp, tx);
 174
 175         /* swap next's deadlist to our deadlist */
 176         dsl_deadlist_close(&ds->ds_deadlist);
 177         dsl_deadlist_close(&ds_next->ds_deadlist);
 178         deadlist_obj = dsl_dataset_phys(ds)->ds_deadlist_obj;
 179         dsl_dataset_phys(ds)->ds_deadlist_obj =
 180             dsl_dataset_phys(ds_next)->ds_deadlist_obj;
 181         dsl_dataset_phys(ds_next)->ds_deadlist_obj = deadlist_obj;
 182         dsl_deadlist_open(&ds->ds_deadlist, mos,
 183             dsl_dataset_phys(ds)->ds_deadlist_obj);
 184         dsl_deadlist_open(&ds_next->ds_deadlist, mos,
 185             dsl_dataset_phys(ds_next)->ds_deadlist_obj);
 186 }
 187
 188 typedef struct remaining_clones_key {
 189         dsl_dataset_t *rck_clone;
 190         list_node_t rck_node;
 191 } remaining_clones_key_t;
 192
 193 static remaining_clones_key_t *
 194 rck_alloc(dsl_dataset_t *clone)
 195 {
 196         remaining_clones_key_t *rck = kmem_alloc(sizeof (*rck), KM_SLEEP);
 197         rck->rck_clone = clone;
 198         return (rck);
 199 }
 200
 201 static void
 202 dsl_dir_remove_clones_key_impl(dsl_dir_t *dd, uint64_t mintxg, dmu_tx_t *tx,
 203     list_t *stack, void *tag)
 204 {
 205         objset_t *mos = dd->dd_pool->dp_meta_objset;
 206
 207         /*
 208          * If it is the old version, dd_clones doesn't exist so we can't
 209          * find the clones, but dsl_deadlist_remove_key() is a no-op so it
 210          * doesn't matter.
 211          */
 212         if (dsl_dir_phys(dd)->dd_clones == 0)
 213                 return;
 214
 215         zap_cursor_t *zc = kmem_alloc(sizeof (zap_cursor_t), KM_SLEEP);
 216         zap_attribute_t *za = kmem_alloc(sizeof (zap_attribute_t), KM_SLEEP);
 217
 218         for (zap_cursor_init(zc, mos, dsl_dir_phys(dd)->dd_clones);
 219             zap_cursor_retrieve(zc, za) == 0;
 220             zap_cursor_advance(zc)) {
 221                 dsl_dataset_t *clone;
 222
 223                 VERIFY0(dsl_dataset_hold_obj(dd->dd_pool,
 224                     za->za_first_integer, tag, &clone));
 225
 226                 if (clone->ds_dir->dd_origin_txg > mintxg) {
 227                         dsl_deadlist_remove_key(&clone->ds_deadlist,
 228                             mintxg, tx);
 229
 230                         if (dsl_dataset_remap_deadlist_exists(clone)) {
 231                                 dsl_deadlist_remove_key(
 232                                     &clone->ds_remap_deadlist, mintxg, tx);
 233                         }
 234
 235                         list_insert_head(stack, rck_alloc(clone));
 236                 } else {
 237                         dsl_dataset_rele(clone, tag);
 238                 }
 239         }
 240         zap_cursor_fini(zc);
 241
 242         kmem_free(za, sizeof (zap_attribute_t));
 243         kmem_free(zc, sizeof (zap_cursor_t));
 244 }
 245
 246 void
 247 dsl_dir_remove_clones_key(dsl_dir_t *top_dd, uint64_t mintxg, dmu_tx_t *tx)
 248 {
 249         list_t stack;
 250
 251         list_create(&stack, sizeof (remaining_clones_key_t),
 252             offsetof(remaining_clones_key_t, rck_node));
 253
 254         dsl_dir_remove_clones_key_impl(top_dd, mintxg, tx, &stack, FTAG);
 255         for (remaining_clones_key_t *rck = list_remove_head(&stack);
 256             rck != NULL; rck = list_remove_head(&stack)) {
 257                 dsl_dataset_t *clone = rck->rck_clone;
 258                 dsl_dir_t *clone_dir = clone->ds_dir;
 259
 260                 kmem_free(rck, sizeof (*rck));
 261
 262                 dsl_dir_remove_clones_key_impl(clone_dir, mintxg, tx,
 263                     &stack, FTAG);
 264                 dsl_dataset_rele(clone, FTAG);
 265         }
 266
 267         list_destroy(&stack);
 268 }
 269
 270 static void
 271 dsl_destroy_snapshot_handle_remaps(dsl_dataset_t *ds, dsl_dataset_t *ds_next,
 272     dmu_tx_t *tx)
 273 {
 274         dsl_pool_t *dp = ds->ds_dir->dd_pool;
 275
 276         /* Move blocks to be obsoleted to pool's obsolete list. */
 277         if (dsl_dataset_remap_deadlist_exists(ds_next)) {
 278                 if (!bpobj_is_open(&dp->dp_obsolete_bpobj))
 279                         dsl_pool_create_obsolete_bpobj(dp, tx);
 280
 281                 dsl_deadlist_move_bpobj(&ds_next->ds_remap_deadlist,
 282                     &dp->dp_obsolete_bpobj,
 283                     dsl_dataset_phys(ds)->ds_prev_snap_txg, tx);
 284         }
 285
 286         /* Merge our deadlist into next's and free it. */
 287         if (dsl_dataset_remap_deadlist_exists(ds)) {
 288                 uint64_t remap_deadlist_object =
 289                     dsl_dataset_get_remap_deadlist_object(ds);
 290                 ASSERT(remap_deadlist_object != 0);
 291
 292                 mutex_enter(&ds_next->ds_remap_deadlist_lock);
 293                 if (!dsl_dataset_remap_deadlist_exists(ds_next))
 294                         dsl_dataset_create_remap_deadlist(ds_next, tx);
 295                 mutex_exit(&ds_next->ds_remap_deadlist_lock);
 296
 297                 dsl_deadlist_merge(&ds_next->ds_remap_deadlist,
 298                     remap_deadlist_object, tx);
 299                 dsl_dataset_destroy_remap_deadlist(ds, tx);
 300         }
 301 }
 302
 303 void
 304 dsl_destroy_snapshot_sync_impl(dsl_dataset_t *ds, boolean_t defer, dmu_tx_t *tx)
 305 {
 306         int after_branch_point = FALSE;
 307         dsl_pool_t *dp = ds->ds_dir->dd_pool;
 308         objset_t *mos = dp->dp_meta_objset;
 309         dsl_dataset_t *ds_prev = NULL;
 310         uint64_t obj;
 311
 312         ASSERT(RRW_WRITE_HELD(&dp->dp_config_rwlock));
 313         rrw_enter(&ds->ds_bp_rwlock, RW_READER, FTAG);
 314         ASSERT3U(dsl_dataset_phys(ds)->ds_bp.blk_birth, <=, tx->tx_txg);
 315         rrw_exit(&ds->ds_bp_rwlock, FTAG);
 316         ASSERT(zfs_refcount_is_zero(&ds->ds_longholds));
 317
 318         if (defer &&
 319             (ds->ds_userrefs > 0 ||
 320             dsl_dataset_phys(ds)->ds_num_children > 1)) {
 321                 ASSERT(spa_version(dp->dp_spa) >= SPA_VERSION_USERREFS);
 322                 dmu_buf_will_dirty(ds->ds_dbuf, tx);
 323                 dsl_dataset_phys(ds)->ds_flags |= DS_FLAG_DEFER_DESTROY;
 324                 spa_history_log_internal_ds(ds, "defer_destroy", tx, " ");
 325                 return;
 326         }
 327
 328         ASSERT3U(dsl_dataset_phys(ds)->ds_num_children, <=, 1);
 329
 330         /* We need to log before removing it from the namespace. */
 331         spa_history_log_internal_ds(ds, "destroy", tx, " ");
 332
 333         dsl_scan_ds_destroyed(ds, tx);
 334
 335         obj = ds->ds_object;
 336
 337         boolean_t book_exists = dsl_bookmark_ds_destroyed(ds, tx);
 338
 339         for (spa_feature_t f = 0; f < SPA_FEATURES; f++) {
 340                 if (dsl_dataset_feature_is_active(ds, f))
 341                         dsl_dataset_deactivate_feature(ds, f, tx);
 342         }
 343         if (dsl_dataset_phys(ds)->ds_prev_snap_obj != 0) {
 344                 ASSERT3P(ds->ds_prev, ==, NULL);
 345                 VERIFY0(dsl_dataset_hold_obj(dp,
 346                     dsl_dataset_phys(ds)->ds_prev_snap_obj, FTAG, &ds_prev));
 347                 after_branch_point =
 348                     (dsl_dataset_phys(ds_prev)->ds_next_snap_obj != obj);
 349
 350                 dmu_buf_will_dirty(ds_prev->ds_dbuf, tx);
 351                 if (after_branch_point &&
 352                     dsl_dataset_phys(ds_prev)->ds_next_clones_obj != 0) {
 353                         dsl_dataset_remove_from_next_clones(ds_prev, obj, tx);
 354                         if (dsl_dataset_phys(ds)->ds_next_snap_obj != 0) {
 355                                 VERIFY0(zap_add_int(mos,
 356                                     dsl_dataset_phys(ds_prev)->
 357                                     ds_next_clones_obj,
 358                                     dsl_dataset_phys(ds)->ds_next_snap_obj,
 359                                     tx));
 360                         }
 361                 }
 362                 if (!after_branch_point) {
 363                         dsl_dataset_phys(ds_prev)->ds_next_snap_obj =
 364                             dsl_dataset_phys(ds)->ds_next_snap_obj;
 365                 }
 366         }
 367
 368         dsl_dataset_t *ds_next;
 369         uint64_t old_unique;
 370         uint64_t used = 0, comp = 0, uncomp = 0;
 371
 372         VERIFY0(dsl_dataset_hold_obj(dp,
 373             dsl_dataset_phys(ds)->ds_next_snap_obj, FTAG, &ds_next));
 374         ASSERT3U(dsl_dataset_phys(ds_next)->ds_prev_snap_obj, ==, obj);
 375
 376         old_unique = dsl_dataset_phys(ds_next)->ds_unique_bytes;
 377
 378         dmu_buf_will_dirty(ds_next->ds_dbuf, tx);
 379         dsl_dataset_phys(ds_next)->ds_prev_snap_obj =
 380             dsl_dataset_phys(ds)->ds_prev_snap_obj;
 381         dsl_dataset_phys(ds_next)->ds_prev_snap_txg =
 382             dsl_dataset_phys(ds)->ds_prev_snap_txg;
 383         ASSERT3U(dsl_dataset_phys(ds)->ds_prev_snap_txg, ==,
 384             ds_prev ? dsl_dataset_phys(ds_prev)->ds_creation_txg : 0);
 385
 386         if (ds_next->ds_deadlist.dl_oldfmt) {
 387                 process_old_deadlist(ds, ds_prev, ds_next,
 388                     after_branch_point, tx);
 389         } else {
 390                 /* Adjust prev's unique space. */
 391                 if (ds_prev && !after_branch_point) {
 392                         dsl_deadlist_space_range(&ds_next->ds_deadlist,
 393                             dsl_dataset_phys(ds_prev)->ds_prev_snap_txg,
 394                             dsl_dataset_phys(ds)->ds_prev_snap_txg,
 395                             &used, &comp, &uncomp);
 396                         dsl_dataset_phys(ds_prev)->ds_unique_bytes += used;
 397                 }
 398
 399                 /* Adjust snapused. */
 400                 dsl_deadlist_space_range(&ds_next->ds_deadlist,
 401                     dsl_dataset_phys(ds)->ds_prev_snap_txg, UINT64_MAX,
 402                     &used, &comp, &uncomp);
 403                 dsl_dir_diduse_space(ds->ds_dir, DD_USED_SNAP,
 404                     -used, -comp, -uncomp, tx);
 405
 406                 /* Move blocks to be freed to pool's free list. */
 407                 dsl_deadlist_move_bpobj(&ds_next->ds_deadlist,
 408                     &dp->dp_free_bpobj, dsl_dataset_phys(ds)->ds_prev_snap_txg,
 409                     tx);
 410                 dsl_dir_diduse_space(tx->tx_pool->dp_free_dir,
 411                     DD_USED_HEAD, used, comp, uncomp, tx);
 412
 413                 /* Merge our deadlist into next's and free it. */
 414                 dsl_deadlist_merge(&ds_next->ds_deadlist,
 415                     dsl_dataset_phys(ds)->ds_deadlist_obj, tx);
 416
 417                 /*
 418                  * We are done with the deadlist tree (generated/used
 419                  * by dsl_deadlist_move_bpobj() and dsl_deadlist_merge()).
 420                  * Discard it to save memory.
 421                  */
 422                 dsl_deadlist_discard_tree(&ds_next->ds_deadlist);
 423         }
 424
 425         dsl_deadlist_close(&ds->ds_deadlist);
 426         dsl_deadlist_free(mos, dsl_dataset_phys(ds)->ds_deadlist_obj, tx);
 427         dmu_buf_will_dirty(ds->ds_dbuf, tx);
 428         dsl_dataset_phys(ds)->ds_deadlist_obj = 0;
 429
 430         dsl_destroy_snapshot_handle_remaps(ds, ds_next, tx);
 431
 432         if (!book_exists) {
 433                 /* Collapse range in clone heads */
 434                 dsl_dir_remove_clones_key(ds->ds_dir,
 435                     dsl_dataset_phys(ds)->ds_creation_txg, tx);
 436         }
 437
 438         if (ds_next->ds_is_snapshot) {
 439                 dsl_dataset_t *ds_nextnext;
 440
 441                 /*
 442                  * Update next's unique to include blocks which
 443                  * were previously shared by only this snapshot
 444                  * and it.  Those blocks will be born after the
 445                  * prev snap and before this snap, and will have
 446                  * died after the next snap and before the one
 447                  * after that (ie. be on the snap after next's
 448                  * deadlist).
 449                  */
 450                 VERIFY0(dsl_dataset_hold_obj(dp,
 451                     dsl_dataset_phys(ds_next)->ds_next_snap_obj,
 452                     FTAG, &ds_nextnext));
 453                 dsl_deadlist_space_range(&ds_nextnext->ds_deadlist,
 454                     dsl_dataset_phys(ds)->ds_prev_snap_txg,
 455                     dsl_dataset_phys(ds)->ds_creation_txg,
 456                     &used, &comp, &uncomp);
 457                 dsl_dataset_phys(ds_next)->ds_unique_bytes += used;
 458                 dsl_dataset_rele(ds_nextnext, FTAG);
 459                 ASSERT3P(ds_next->ds_prev, ==, NULL);
 460
 461                 /* Collapse range in this head. */
 462                 dsl_dataset_t *hds;
 463                 VERIFY0(dsl_dataset_hold_obj(dp,
 464                     dsl_dir_phys(ds->ds_dir)->dd_head_dataset_obj,
 465                     FTAG, &hds));
 466                 if (!book_exists) {
 467                         /* Collapse range in this head. */
 468                         dsl_deadlist_remove_key(&hds->ds_deadlist,
 469                             dsl_dataset_phys(ds)->ds_creation_txg, tx);
 470                 }
 471                 if (dsl_dataset_remap_deadlist_exists(hds)) {
 472                         dsl_deadlist_remove_key(&hds->ds_remap_deadlist,
 473                             dsl_dataset_phys(ds)->ds_creation_txg, tx);
 474                 }
 475                 dsl_dataset_rele(hds, FTAG);
 476
 477         } else {
 478                 ASSERT3P(ds_next->ds_prev, ==, ds);
 479                 dsl_dataset_rele(ds_next->ds_prev, ds_next);
 480                 ds_next->ds_prev = NULL;
 481                 if (ds_prev) {
 482                         VERIFY0(dsl_dataset_hold_obj(dp,
 483                             dsl_dataset_phys(ds)->ds_prev_snap_obj,
 484                             ds_next, &ds_next->ds_prev));
 485                 }
 486
 487                 dsl_dataset_recalc_head_uniq(ds_next);
 488
 489                 /*
 490                  * Reduce the amount of our unconsumed refreservation
 491                  * being charged to our parent by the amount of
 492                  * new unique data we have gained.
 493                  */
 494                 if (old_unique < ds_next->ds_reserved) {
 495                         int64_t mrsdelta;
 496                         uint64_t new_unique =
 497                             dsl_dataset_phys(ds_next)->ds_unique_bytes;
 498
 499                         ASSERT(old_unique <= new_unique);
 500                         mrsdelta = MIN(new_unique - old_unique,
 501                             ds_next->ds_reserved - old_unique);
 502                         dsl_dir_diduse_space(ds->ds_dir,
 503                             DD_USED_REFRSRV, -mrsdelta, 0, 0, tx);
 504                 }
 505         }
 506         dsl_dataset_rele(ds_next, FTAG);
 507
 508         /*
 509          * This must be done after the dsl_traverse(), because it will
 510          * re-open the objset.
 511          */
 512         if (ds->ds_objset) {
 513                 dmu_objset_evict(ds->ds_objset);
 514                 ds->ds_objset = NULL;
 515         }
 516
 517         /* remove from snapshot namespace */
 518         dsl_dataset_t *ds_head;
 519         ASSERT(dsl_dataset_phys(ds)->ds_snapnames_zapobj == 0);
 520         VERIFY0(dsl_dataset_hold_obj(dp,
 521             dsl_dir_phys(ds->ds_dir)->dd_head_dataset_obj, FTAG, &ds_head));
 522         VERIFY0(dsl_dataset_get_snapname(ds));
 523 #ifdef ZFS_DEBUG
 524         {
 525                 uint64_t val;
 526                 int err;
 527
 528                 err = dsl_dataset_snap_lookup(ds_head,
 529                     ds->ds_snapname, &val);
 530                 ASSERT0(err);
 531                 ASSERT3U(val, ==, obj);
 532         }
 533 #endif
 534         VERIFY0(dsl_dataset_snap_remove(ds_head, ds->ds_snapname, tx, B_TRUE));
 535         dsl_dataset_rele(ds_head, FTAG);
 536
 537         if (ds_prev != NULL)
 538                 dsl_dataset_rele(ds_prev, FTAG);
 539
 540         spa_prop_clear_bootfs(dp->dp_spa, ds->ds_object, tx);
 541
 542         if (dsl_dataset_phys(ds)->ds_next_clones_obj != 0) {
 543                 uint64_t count __maybe_unused;
 544                 ASSERT0(zap_count(mos,
 545                     dsl_dataset_phys(ds)->ds_next_clones_obj, &count) &&
 546                     count == 0);
 547                 VERIFY0(dmu_object_free(mos,
 548                     dsl_dataset_phys(ds)->ds_next_clones_obj, tx));
 549         }
 550         if (dsl_dataset_phys(ds)->ds_props_obj != 0)
 551                 VERIFY0(zap_destroy(mos, dsl_dataset_phys(ds)->ds_props_obj,
 552                     tx));
 553         if (dsl_dataset_phys(ds)->ds_userrefs_obj != 0)
 554                 VERIFY0(zap_destroy(mos, dsl_dataset_phys(ds)->ds_userrefs_obj,
 555                     tx));
 556         dsl_dir_rele(ds->ds_dir, ds);
 557         ds->ds_dir = NULL;
 558         dmu_object_free_zapified(mos, obj, tx);
 559 }
 560
 561 void
 562 dsl_destroy_snapshot_sync(void *arg, dmu_tx_t *tx)
 563 {
 564         dsl_destroy_snapshot_arg_t *ddsa = arg;
 565         const char *dsname = ddsa->ddsa_name;
 566         boolean_t defer = ddsa->ddsa_defer;
 567
 568         dsl_pool_t *dp = dmu_tx_pool(tx);
 569         dsl_dataset_t *ds;
 570
 571         int error = dsl_dataset_hold(dp, dsname, FTAG, &ds);
 572         if (error == ENOENT)
 573                 return;
 574         ASSERT0(error);
 575         dsl_destroy_snapshot_sync_impl(ds, defer, tx);
 576         zvol_remove_minors(dp->dp_spa, dsname, B_TRUE);
 577         dsl_dataset_rele(ds, FTAG);
 578 }
 579
 580 /*
 581  * The semantics of this function are described in the comment above
 582  * lzc_destroy_snaps().  To summarize:
 583  *
 584  * The snapshots must all be in the same pool.
 585  *
 586  * Snapshots that don't exist will be silently ignored (considered to be
 587  * "already deleted").
 588  *
 589  * On success, all snaps will be destroyed and this will return 0.
 590  * On failure, no snaps will be destroyed, the errlist will be filled in,
 591  * and this will return an errno.
 592  */
 593 int
 594 dsl_destroy_snapshots_nvl(nvlist_t *snaps, boolean_t defer,
 595     nvlist_t *errlist)
 596 {
 597         if (nvlist_next_nvpair(snaps, NULL) == NULL)
 598                 return (0);
 599
 600         /*
 601          * lzc_destroy_snaps() is documented to take an nvlist whose
 602          * values "don't matter".  We need to convert that nvlist to
 603          * one that we know can be converted to LUA. We also don't
 604          * care about any duplicate entries because the nvlist will
 605          * be converted to a LUA table which should take care of this.
 606          */
 607         nvlist_t *snaps_normalized;
 608         VERIFY0(nvlist_alloc(&snaps_normalized, 0, KM_SLEEP));
 609         for (nvpair_t *pair = nvlist_next_nvpair(snaps, NULL);
 610             pair != NULL; pair = nvlist_next_nvpair(snaps, pair)) {
 611                 fnvlist_add_boolean_value(snaps_normalized,
 612                     nvpair_name(pair), B_TRUE);
 613         }
 614
 615         nvlist_t *arg;
 616         VERIFY0(nvlist_alloc(&arg, 0, KM_SLEEP));
 617         fnvlist_add_nvlist(arg, "snaps", snaps_normalized);
 618         fnvlist_free(snaps_normalized);
 619         fnvlist_add_boolean_value(arg, "defer", defer);
 620
 621         nvlist_t *wrapper;
 622         VERIFY0(nvlist_alloc(&wrapper, 0, KM_SLEEP));
 623         fnvlist_add_nvlist(wrapper, ZCP_ARG_ARGLIST, arg);
 624         fnvlist_free(arg);
 625
 626         const char *program =
 627             "arg = ...\n"
 628             "snaps = arg['snaps']\n"
 629             "defer = arg['defer']\n"
 630             "errors = { }\n"
 631             "has_errors = false\n"
 632             "for snap, v in pairs(snaps) do\n"
 633             "    errno = zfs.check.destroy{snap, defer=defer}\n"
 634             "    zfs.debug('snap: ' .. snap .. ' errno: ' .. errno)\n"
 635             "    if errno == ENOENT then\n"
 636             "        snaps[snap] = nil\n"
 637             "    elseif errno ~= 0 then\n"
 638             "        errors[snap] = errno\n"
 639             "        has_errors = true\n"
 640             "    end\n"
 641             "end\n"
 642             "if has_errors then\n"
 643             "    return errors\n"
 644             "end\n"
 645             "for snap, v in pairs(snaps) do\n"
 646             "    errno = zfs.sync.destroy{snap, defer=defer}\n"
 647             "    assert(errno == 0)\n"
 648             "end\n"
 649             "return { }\n";
 650
 651         nvlist_t *result = fnvlist_alloc();
 652         int error = zcp_eval(nvpair_name(nvlist_next_nvpair(snaps, NULL)),
 653             program,
 654             B_TRUE,
 655             0,
 656             zfs_lua_max_memlimit,
 657             nvlist_next_nvpair(wrapper, NULL), result);
 658         if (error != 0) {
 659                 char *errorstr = NULL;
 660                 (void) nvlist_lookup_string(result, ZCP_RET_ERROR, &errorstr);
 661                 if (errorstr != NULL) {
 662                         zfs_dbgmsg(errorstr);
 663                 }
 664                 fnvlist_free(wrapper);
 665                 fnvlist_free(result);
 666                 return (error);
 667         }
 668         fnvlist_free(wrapper);
 669
 670         /*
 671          * lzc_destroy_snaps() is documented to fill the errlist with
 672          * int32 values, so we need to convert the int64 values that are
 673          * returned from LUA.
 674          */
 675         int rv = 0;
 676         nvlist_t *errlist_raw = fnvlist_lookup_nvlist(result, ZCP_RET_RETURN);
 677         for (nvpair_t *pair = nvlist_next_nvpair(errlist_raw, NULL);
 678             pair != NULL; pair = nvlist_next_nvpair(errlist_raw, pair)) {
 679                 int32_t val = (int32_t)fnvpair_value_int64(pair);
 680                 if (rv == 0)
 681                         rv = val;
 682                 fnvlist_add_int32(errlist, nvpair_name(pair), val);
 683         }
 684         fnvlist_free(result);
 685         return (rv);
 686 }
 687
 688 int
 689 dsl_destroy_snapshot(const char *name, boolean_t defer)
 690 {
 691         int error;
 692         nvlist_t *nvl = fnvlist_alloc();
 693         nvlist_t *errlist = fnvlist_alloc();
 694
 695         fnvlist_add_boolean(nvl, name);
 696         error = dsl_destroy_snapshots_nvl(nvl, defer, errlist);
 697         fnvlist_free(errlist);
 698         fnvlist_free(nvl);
 699         return (error);
 700 }
 701
 702 struct killarg {
 703         dsl_dataset_t *ds;
 704         dmu_tx_t *tx;
 705 };
 706
 707 /* ARGSUSED */
 708 static int
 709 kill_blkptr(spa_t *spa, zilog_t *zilog, const blkptr_t *bp,
 710     const zbookmark_phys_t *zb, const dnode_phys_t *dnp, void *arg)
 711 {
 712         struct killarg *ka = arg;
 713         dmu_tx_t *tx = ka->tx;
 714
 715         if (zb->zb_level == ZB_DNODE_LEVEL || BP_IS_HOLE(bp) ||
 716             BP_IS_EMBEDDED(bp))
 717                 return (0);
 718
 719         if (zb->zb_level == ZB_ZIL_LEVEL) {
 720                 ASSERT(zilog != NULL);
 721                 /*
 722                  * It's a block in the intent log.  It has no
 723                  * accounting, so just free it.
 724                  */
 725                 dsl_free(ka->tx->tx_pool, ka->tx->tx_txg, bp);
 726         } else {
 727                 ASSERT(zilog == NULL);
 728                 ASSERT3U(bp->blk_birth, >,
 729                     dsl_dataset_phys(ka->ds)->ds_prev_snap_txg);
 730                 (void) dsl_dataset_block_kill(ka->ds, bp, tx, B_FALSE);
 731         }
 732
 733         return (0);
 734 }
 735
 736 static void
 737 old_synchronous_dataset_destroy(dsl_dataset_t *ds, dmu_tx_t *tx)
 738 {
 739         struct killarg ka;
 740
 741         spa_history_log_internal_ds(ds, "destroy", tx,
 742             "(synchronous, mintxg=%llu)",
 743             (long long)dsl_dataset_phys(ds)->ds_prev_snap_txg);
 744
 745         /*
 746          * Free everything that we point to (that's born after
 747          * the previous snapshot, if we are a clone)
 748          *
 749          * NB: this should be very quick, because we already
 750          * freed all the objects in open context.
 751          */
 752         ka.ds = ds;
 753         ka.tx = tx;
 754         VERIFY0(traverse_dataset(ds,
 755             dsl_dataset_phys(ds)->ds_prev_snap_txg, TRAVERSE_POST |
 756             TRAVERSE_NO_DECRYPT, kill_blkptr, &ka));
 757         ASSERT(!DS_UNIQUE_IS_ACCURATE(ds) ||
 758             dsl_dataset_phys(ds)->ds_unique_bytes == 0);
 759 }
 760
 761 int
 762 dsl_destroy_head_check_impl(dsl_dataset_t *ds, int expected_holds)
 763 {
 764         int error;
 765         uint64_t count;
 766         objset_t *mos;
 767
 768         ASSERT(!ds->ds_is_snapshot);
 769         if (ds->ds_is_snapshot)
 770                 return (SET_ERROR(EINVAL));
 771
 772         if (zfs_refcount_count(&ds->ds_longholds) != expected_holds)
 773                 return (SET_ERROR(EBUSY));
 774
 775         ASSERT0(ds->ds_dir->dd_activity_waiters);
 776
 777         mos = ds->ds_dir->dd_pool->dp_meta_objset;
 778
 779         /*
 780          * Can't delete a head dataset if there are snapshots of it.
 781          * (Except if the only snapshots are from the branch we cloned
 782          * from.)
 783          */
 784         if (ds->ds_prev != NULL &&
 785             dsl_dataset_phys(ds->ds_prev)->ds_next_snap_obj == ds->ds_object)
 786                 return (SET_ERROR(EBUSY));
 787
 788         /*
 789          * Can't delete if there are children of this fs.
 790          */
 791         error = zap_count(mos,
 792             dsl_dir_phys(ds->ds_dir)->dd_child_dir_zapobj, &count);
 793         if (error != 0)
 794                 return (error);
 795         if (count != 0)
 796                 return (SET_ERROR(EEXIST));
 797
 798         if (dsl_dir_is_clone(ds->ds_dir) && DS_IS_DEFER_DESTROY(ds->ds_prev) &&
 799             dsl_dataset_phys(ds->ds_prev)->ds_num_children == 2 &&
 800             ds->ds_prev->ds_userrefs == 0) {
 801                 /* We need to remove the origin snapshot as well. */
 802                 if (!zfs_refcount_is_zero(&ds->ds_prev->ds_longholds))
 803                         return (SET_ERROR(EBUSY));
 804         }
 805         return (0);
 806 }
 807
 808 int
 809 dsl_destroy_head_check(void *arg, dmu_tx_t *tx)
 810 {
 811         dsl_destroy_head_arg_t *ddha = arg;
 812         dsl_pool_t *dp = dmu_tx_pool(tx);
 813         dsl_dataset_t *ds;
 814         int error;
 815
 816         error = dsl_dataset_hold(dp, ddha->ddha_name, FTAG, &ds);
 817         if (error != 0)
 818                 return (error);
 819
 820         error = dsl_destroy_head_check_impl(ds, 0);
 821         dsl_dataset_rele(ds, FTAG);
 822         return (error);
 823 }
 824
 825 static void
 826 dsl_dir_destroy_sync(uint64_t ddobj, dmu_tx_t *tx)
 827 {
 828         dsl_dir_t *dd;
 829         dsl_pool_t *dp = dmu_tx_pool(tx);
 830         objset_t *mos = dp->dp_meta_objset;
 831         dd_used_t t;
 832
 833         ASSERT(RRW_WRITE_HELD(&dmu_tx_pool(tx)->dp_config_rwlock));
 834
 835         VERIFY0(dsl_dir_hold_obj(dp, ddobj, NULL, FTAG, &dd));
 836
 837         ASSERT0(dsl_dir_phys(dd)->dd_head_dataset_obj);
 838
 839         /* Decrement the filesystem count for all parent filesystems. */
 840         if (dd->dd_parent != NULL)
 841                 dsl_fs_ss_count_adjust(dd->dd_parent, -1,
 842                     DD_FIELD_FILESYSTEM_COUNT, tx);
 843
 844         /*
 845          * Remove our reservation. The impl() routine avoids setting the
 846          * actual property, which would require the (already destroyed) ds.
 847          */
 848         dsl_dir_set_reservation_sync_impl(dd, 0, tx);
 849
 850         ASSERT0(dsl_dir_phys(dd)->dd_used_bytes);
 851         ASSERT0(dsl_dir_phys(dd)->dd_reserved);
 852         for (t = 0; t < DD_USED_NUM; t++)
 853                 ASSERT0(dsl_dir_phys(dd)->dd_used_breakdown[t]);
 854
 855         if (dd->dd_crypto_obj != 0) {
 856                 dsl_crypto_key_destroy_sync(dd->dd_crypto_obj, tx);
 857                 (void) spa_keystore_unload_wkey_impl(dp->dp_spa, dd->dd_object);
 858         }
 859
 860         VERIFY0(zap_destroy(mos, dsl_dir_phys(dd)->dd_child_dir_zapobj, tx));
 861         VERIFY0(zap_destroy(mos, dsl_dir_phys(dd)->dd_props_zapobj, tx));
 862         if (dsl_dir_phys(dd)->dd_clones != 0)
 863                 VERIFY0(zap_destroy(mos, dsl_dir_phys(dd)->dd_clones, tx));
 864         VERIFY0(dsl_deleg_destroy(mos, dsl_dir_phys(dd)->dd_deleg_zapobj, tx));
 865         VERIFY0(zap_remove(mos,
 866             dsl_dir_phys(dd->dd_parent)->dd_child_dir_zapobj,
 867             dd->dd_myname, tx));
 868
 869         dsl_dir_rele(dd, FTAG);
 870         dmu_object_free_zapified(mos, ddobj, tx);
 871 }
 872
 873 static void
 874 dsl_clone_destroy_assert(dsl_dir_t *dd)
 875 {
 876         uint64_t used, comp, uncomp;
 877
 878         ASSERT(dsl_dir_is_clone(dd));
 879         dsl_deadlist_space(&dd->dd_livelist, &used, &comp, &uncomp);
 880
 881         ASSERT3U(dsl_dir_phys(dd)->dd_used_bytes, ==, used);
 882         ASSERT3U(dsl_dir_phys(dd)->dd_compressed_bytes, ==, comp);
 883         /*
 884          * Greater than because we do not track embedded block pointers in
 885          * the livelist
 886          */
 887         ASSERT3U(dsl_dir_phys(dd)->dd_uncompressed_bytes, >=, uncomp);
 888
 889         ASSERT(list_is_empty(&dd->dd_pending_allocs.bpl_list));
 890         ASSERT(list_is_empty(&dd->dd_pending_frees.bpl_list));
 891 }
 892
 893 /*
 894  * Start the delete process for a clone. Free its zil, verify the space usage
 895  * and queue the blkptrs for deletion by adding the livelist to the pool-wide
 896  * delete queue.
 897  */
 898 static void
 899 dsl_async_clone_destroy(dsl_dataset_t *ds, dmu_tx_t *tx)
 900 {
 901         uint64_t zap_obj, to_delete, used, comp, uncomp;
 902         objset_t *os;
 903         dsl_dir_t *dd = ds->ds_dir;
 904         dsl_pool_t *dp = dmu_tx_pool(tx);
 905         objset_t *mos = dp->dp_meta_objset;
 906         spa_t *spa = dmu_tx_pool(tx)->dp_spa;
 907         VERIFY0(dmu_objset_from_ds(ds, &os));
 908
 909         uint64_t mintxg = 0;
 910         dsl_deadlist_entry_t *dle = dsl_deadlist_first(&dd->dd_livelist);
 911         if (dle != NULL)
 912                 mintxg = dle->dle_mintxg;
 913
 914         spa_history_log_internal_ds(ds, "destroy", tx,
 915             "(livelist, mintxg=%llu)", (long long)mintxg);
 916
 917         /* Check that the clone is in a correct state to be deleted */
 918         dsl_clone_destroy_assert(dd);
 919
 920         /* Destroy the zil */
 921         zil_destroy_sync(dmu_objset_zil(os), tx);
 922
 923         VERIFY0(zap_lookup(mos, dd->dd_object,
 924             DD_FIELD_LIVELIST, sizeof (uint64_t), 1, &to_delete));
 925         /* Initialize deleted_clones entry to track livelists to cleanup */
 926         int error = zap_lookup(mos, DMU_POOL_DIRECTORY_OBJECT,
 927             DMU_POOL_DELETED_CLONES, sizeof (uint64_t), 1, &zap_obj);
 928         if (error == ENOENT) {
 929                 zap_obj = zap_create(mos, DMU_OTN_ZAP_METADATA,
 930                     DMU_OT_NONE, 0, tx);
 931                 VERIFY0(zap_add(mos, DMU_POOL_DIRECTORY_OBJECT,
 932                     DMU_POOL_DELETED_CLONES, sizeof (uint64_t), 1,
 933                     &(zap_obj), tx));
 934                 spa->spa_livelists_to_delete = zap_obj;
 935         } else if (error != 0) {
 936                 zfs_panic_recover("zfs: error %d was returned while looking "
 937                     "up DMU_POOL_DELETED_CLONES in the zap", error);
 938                 return;
 939         }
 940         VERIFY0(zap_add_int(mos, zap_obj, to_delete, tx));
 941
 942         /* Clone is no longer using space, now tracked by dp_free_dir */
 943         dsl_deadlist_space(&dd->dd_livelist, &used, &comp, &uncomp);
 944         dsl_dir_diduse_space(dd, DD_USED_HEAD,
 945             -used, -comp, -dsl_dir_phys(dd)->dd_uncompressed_bytes,
 946             tx);
 947         dsl_dir_diduse_space(dp->dp_free_dir, DD_USED_HEAD,
 948             used, comp, uncomp, tx);
 949         dsl_dir_remove_livelist(dd, tx, B_FALSE);
 950         zthr_wakeup(spa->spa_livelist_delete_zthr);
 951 }
 952
 953 /*
 954  * Move the bptree into the pool's list of trees to clean up, update space
 955  * accounting information and destroy the zil.
 956  */
 957 static void
 958 dsl_async_dataset_destroy(dsl_dataset_t *ds, dmu_tx_t *tx)
 959 {
 960         uint64_t used, comp, uncomp;
 961         objset_t *os;
 962
 963         VERIFY0(dmu_objset_from_ds(ds, &os));
 964         dsl_pool_t *dp = dmu_tx_pool(tx);
 965         objset_t *mos = dp->dp_meta_objset;
 966
 967         spa_history_log_internal_ds(ds, "destroy", tx,
 968             "(bptree, mintxg=%llu)",
 969             (long long)dsl_dataset_phys(ds)->ds_prev_snap_txg);
 970
 971         zil_destroy_sync(dmu_objset_zil(os), tx);
 972
 973         if (!spa_feature_is_active(dp->dp_spa,
 974             SPA_FEATURE_ASYNC_DESTROY)) {
 975                 dsl_scan_t *scn = dp->dp_scan;
 976                 spa_feature_incr(dp->dp_spa, SPA_FEATURE_ASYNC_DESTROY,
 977                     tx);
 978                 dp->dp_bptree_obj = bptree_alloc(mos, tx);
 979                 VERIFY0(zap_add(mos,
 980                     DMU_POOL_DIRECTORY_OBJECT,
 981                     DMU_POOL_BPTREE_OBJ, sizeof (uint64_t), 1,
 982                     &dp->dp_bptree_obj, tx));
 983                 ASSERT(!scn->scn_async_destroying);
 984                 scn->scn_async_destroying = B_TRUE;
 985         }
 986
 987         used = dsl_dir_phys(ds->ds_dir)->dd_used_bytes;
 988         comp = dsl_dir_phys(ds->ds_dir)->dd_compressed_bytes;
 989         uncomp = dsl_dir_phys(ds->ds_dir)->dd_uncompressed_bytes;
 990
 991         ASSERT(!DS_UNIQUE_IS_ACCURATE(ds) ||
 992             dsl_dataset_phys(ds)->ds_unique_bytes == used);
 993
 994         rrw_enter(&ds->ds_bp_rwlock, RW_READER, FTAG);
 995         bptree_add(mos, dp->dp_bptree_obj,
 996             &dsl_dataset_phys(ds)->ds_bp,
 997             dsl_dataset_phys(ds)->ds_prev_snap_txg,
 998             used, comp, uncomp, tx);
 999         rrw_exit(&ds->ds_bp_rwlock, FTAG);
1000         dsl_dir_diduse_space(ds->ds_dir, DD_USED_HEAD,
1001             -used, -comp, -uncomp, tx);
1002         dsl_dir_diduse_space(dp->dp_free_dir, DD_USED_HEAD,
1003             used, comp, uncomp, tx);
1004 }
1005
1006 void
1007 dsl_destroy_head_sync_impl(dsl_dataset_t *ds, dmu_tx_t *tx)
1008 {
1009         dsl_pool_t *dp = dmu_tx_pool(tx);
1010         objset_t *mos = dp->dp_meta_objset;
1011         uint64_t obj, ddobj, prevobj = 0;
1012         boolean_t rmorigin;
1013
1014         ASSERT3U(dsl_dataset_phys(ds)->ds_num_children, <=, 1);
1015         ASSERT(ds->ds_prev == NULL ||
1016             dsl_dataset_phys(ds->ds_prev)->ds_next_snap_obj != ds->ds_object);
1017         rrw_enter(&ds->ds_bp_rwlock, RW_READER, FTAG);
1018         ASSERT3U(dsl_dataset_phys(ds)->ds_bp.blk_birth, <=, tx->tx_txg);
1019         rrw_exit(&ds->ds_bp_rwlock, FTAG);
1020         ASSERT(RRW_WRITE_HELD(&dp->dp_config_rwlock));
1021
1022         dsl_dir_cancel_waiters(ds->ds_dir);
1023
1024         rmorigin = (dsl_dir_is_clone(ds->ds_dir) &&
1025             DS_IS_DEFER_DESTROY(ds->ds_prev) &&
1026             dsl_dataset_phys(ds->ds_prev)->ds_num_children == 2 &&
1027             ds->ds_prev->ds_userrefs == 0);
1028
1029         /* Remove our reservation. */
1030         if (ds->ds_reserved != 0) {
1031                 dsl_dataset_set_refreservation_sync_impl(ds,
1032                     (ZPROP_SRC_NONE | ZPROP_SRC_LOCAL | ZPROP_SRC_RECEIVED),
1033                     0, tx);
1034                 ASSERT0(ds->ds_reserved);
1035         }
1036
1037         obj = ds->ds_object;
1038
1039         for (spa_feature_t f = 0; f < SPA_FEATURES; f++) {
1040                 if (dsl_dataset_feature_is_active(ds, f))
1041                         dsl_dataset_deactivate_feature(ds, f, tx);
1042         }
1043
1044         dsl_scan_ds_destroyed(ds, tx);
1045
1046         if (dsl_dataset_phys(ds)->ds_prev_snap_obj != 0) {
1047                 /* This is a clone */
1048                 ASSERT(ds->ds_prev != NULL);
1049                 ASSERT3U(dsl_dataset_phys(ds->ds_prev)->ds_next_snap_obj, !=,
1050                     obj);
1051                 ASSERT0(dsl_dataset_phys(ds)->ds_next_snap_obj);
1052
1053                 dmu_buf_will_dirty(ds->ds_prev->ds_dbuf, tx);
1054                 if (dsl_dataset_phys(ds->ds_prev)->ds_next_clones_obj != 0) {
1055                         dsl_dataset_remove_from_next_clones(ds->ds_prev,
1056                             obj, tx);
1057                 }
1058
1059                 ASSERT3U(dsl_dataset_phys(ds->ds_prev)->ds_num_children, >, 1);
1060                 dsl_dataset_phys(ds->ds_prev)->ds_num_children--;
1061         }
1062
1063         /*
1064          * Destroy the deadlist. Unless it's a clone, the
1065          * deadlist should be empty since the dataset has no snapshots.
1066          * (If it's a clone, it's safe to ignore the deadlist contents
1067          * since they are still referenced by the origin snapshot.)
1068          */
1069         dsl_deadlist_close(&ds->ds_deadlist);
1070         dsl_deadlist_free(mos, dsl_dataset_phys(ds)->ds_deadlist_obj, tx);
1071         dmu_buf_will_dirty(ds->ds_dbuf, tx);
1072         dsl_dataset_phys(ds)->ds_deadlist_obj = 0;
1073
1074         if (dsl_dataset_remap_deadlist_exists(ds))
1075                 dsl_dataset_destroy_remap_deadlist(ds, tx);
1076
1077         /*
1078          * Each destroy is responsible for both destroying (enqueuing
1079          * to be destroyed) the blkptrs comprising the dataset as well as
1080          * those belonging to the zil.
1081          */
1082         if (dsl_deadlist_is_open(&ds->ds_dir->dd_livelist)) {
1083                 dsl_async_clone_destroy(ds, tx);
1084         } else if (spa_feature_is_enabled(dp->dp_spa,
1085             SPA_FEATURE_ASYNC_DESTROY)) {
1086                 dsl_async_dataset_destroy(ds, tx);
1087         } else {
1088                 old_synchronous_dataset_destroy(ds, tx);
1089         }
1090
1091         if (ds->ds_prev != NULL) {
1092                 if (spa_version(dp->dp_spa) >= SPA_VERSION_DIR_CLONES) {
1093                         VERIFY0(zap_remove_int(mos,
1094                             dsl_dir_phys(ds->ds_prev->ds_dir)->dd_clones,
1095                             ds->ds_object, tx));
1096                 }
1097                 prevobj = ds->ds_prev->ds_object;
1098                 dsl_dataset_rele(ds->ds_prev, ds);
1099                 ds->ds_prev = NULL;
1100         }
1101
1102         /*
1103          * This must be done after the dsl_traverse(), because it will
1104          * re-open the objset.
1105          */
1106         if (ds->ds_objset) {
1107                 dmu_objset_evict(ds->ds_objset);
1108                 ds->ds_objset = NULL;
1109         }
1110
1111         /* Erase the link in the dir */
1112         dmu_buf_will_dirty(ds->ds_dir->dd_dbuf, tx);
1113         dsl_dir_phys(ds->ds_dir)->dd_head_dataset_obj = 0;
1114         ddobj = ds->ds_dir->dd_object;
1115         ASSERT(dsl_dataset_phys(ds)->ds_snapnames_zapobj != 0);
1116         VERIFY0(zap_destroy(mos,
1117             dsl_dataset_phys(ds)->ds_snapnames_zapobj, tx));
1118
1119         if (ds->ds_bookmarks_obj != 0) {
1120                 void *cookie = NULL;
1121                 dsl_bookmark_node_t *dbn;
1122
1123                 while ((dbn = avl_destroy_nodes(&ds->ds_bookmarks, &cookie)) !=
1124                     NULL) {
1125                         if (dbn->dbn_phys.zbm_redaction_obj != 0) {
1126                                 VERIFY0(dmu_object_free(mos,
1127                                     dbn->dbn_phys.zbm_redaction_obj, tx));
1128                                 spa_feature_decr(dmu_objset_spa(mos),
1129                                     SPA_FEATURE_REDACTION_BOOKMARKS, tx);
1130                         }
1131                         if (dbn->dbn_phys.zbm_flags & ZBM_FLAG_HAS_FBN) {
1132                                 spa_feature_decr(dmu_objset_spa(mos),
1133                                     SPA_FEATURE_BOOKMARK_WRITTEN, tx);
1134                         }
1135                         spa_strfree(dbn->dbn_name);
1136                         mutex_destroy(&dbn->dbn_lock);
1137                         kmem_free(dbn, sizeof (*dbn));
1138                 }
1139                 avl_destroy(&ds->ds_bookmarks);
1140                 VERIFY0(zap_destroy(mos, ds->ds_bookmarks_obj, tx));
1141                 spa_feature_decr(dp->dp_spa, SPA_FEATURE_BOOKMARKS, tx);
1142         }
1143
1144         spa_prop_clear_bootfs(dp->dp_spa, ds->ds_object, tx);
1145
1146         ASSERT0(dsl_dataset_phys(ds)->ds_next_clones_obj);
1147         ASSERT0(dsl_dataset_phys(ds)->ds_props_obj);
1148         ASSERT0(dsl_dataset_phys(ds)->ds_userrefs_obj);
1149         dsl_dir_rele(ds->ds_dir, ds);
1150         ds->ds_dir = NULL;
1151         dmu_object_free_zapified(mos, obj, tx);
1152
1153         dsl_dir_destroy_sync(ddobj, tx);
1154
1155         if (rmorigin) {
1156                 dsl_dataset_t *prev;
1157                 VERIFY0(dsl_dataset_hold_obj(dp, prevobj, FTAG, &prev));
1158                 dsl_destroy_snapshot_sync_impl(prev, B_FALSE, tx);
1159                 dsl_dataset_rele(prev, FTAG);
1160         }
1161 }
1162
1163 void
1164 dsl_destroy_head_sync(void *arg, dmu_tx_t *tx)
1165 {
1166         dsl_destroy_head_arg_t *ddha = arg;
1167         dsl_pool_t *dp = dmu_tx_pool(tx);
1168         dsl_dataset_t *ds;
1169
1170         VERIFY0(dsl_dataset_hold(dp, ddha->ddha_name, FTAG, &ds));
1171         dsl_destroy_head_sync_impl(ds, tx);
1172         zvol_remove_minors(dp->dp_spa, ddha->ddha_name, B_TRUE);
1173         dsl_dataset_rele(ds, FTAG);
1174 }
1175
1176 static void
1177 dsl_destroy_head_begin_sync(void *arg, dmu_tx_t *tx)
1178 {
1179         dsl_destroy_head_arg_t *ddha = arg;
1180         dsl_pool_t *dp = dmu_tx_pool(tx);
1181         dsl_dataset_t *ds;
1182
1183         VERIFY0(dsl_dataset_hold(dp, ddha->ddha_name, FTAG, &ds));
1184
1185         /* Mark it as inconsistent on-disk, in case we crash */
1186         dmu_buf_will_dirty(ds->ds_dbuf, tx);
1187         dsl_dataset_phys(ds)->ds_flags |= DS_FLAG_INCONSISTENT;
1188
1189         spa_history_log_internal_ds(ds, "destroy begin", tx, " ");
1190         dsl_dataset_rele(ds, FTAG);
1191 }
1192
1193 int
1194 dsl_destroy_head(const char *name)
1195 {
1196         dsl_destroy_head_arg_t ddha;
1197         int error;
1198         spa_t *spa;
1199         boolean_t isenabled;
1200
1201 #ifdef _KERNEL
1202         zfs_destroy_unmount_origin(name);
1203 #endif
1204
1205         error = spa_open(name, &spa, FTAG);
1206         if (error != 0)
1207                 return (error);
1208         isenabled = spa_feature_is_enabled(spa, SPA_FEATURE_ASYNC_DESTROY);
1209         spa_close(spa, FTAG);
1210
1211         ddha.ddha_name = name;
1212
1213         if (!isenabled) {
1214                 objset_t *os;
1215
1216                 error = dsl_sync_task(name, dsl_destroy_head_check,
1217                     dsl_destroy_head_begin_sync, &ddha,
1218                     0, ZFS_SPACE_CHECK_DESTROY);
1219                 if (error != 0)
1220                         return (error);
1221
1222                 /*
1223                  * Head deletion is processed in one txg on old pools;
1224                  * remove the objects from open context so that the txg sync
1225                  * is not too long. This optimization can only work for
1226                  * encrypted datasets if the wrapping key is loaded.
1227                  */
1228                 error = dmu_objset_own(name, DMU_OST_ANY, B_FALSE, B_TRUE,
1229                     FTAG, &os);
1230                 if (error == 0) {
1231                         uint64_t prev_snap_txg =
1232                             dsl_dataset_phys(dmu_objset_ds(os))->
1233                             ds_prev_snap_txg;
1234                         for (uint64_t obj = 0; error == 0;
1235                             error = dmu_object_next(os, &obj, FALSE,
1236                             prev_snap_txg))
1237                                 (void) dmu_free_long_object(os, obj);
1238                         /* sync out all frees */
1239                         txg_wait_synced(dmu_objset_pool(os), 0);
1240                         dmu_objset_disown(os, B_TRUE, FTAG);
1241                 }
1242         }
1243
1244         return (dsl_sync_task(name, dsl_destroy_head_check,
1245             dsl_destroy_head_sync, &ddha, 0, ZFS_SPACE_CHECK_DESTROY));
1246 }
1247
1248 /*
1249  * Note, this function is used as the callback for dmu_objset_find().  We
1250  * always return 0 so that we will continue to find and process
1251  * inconsistent datasets, even if we encounter an error trying to
1252  * process one of them.
1253  */
1254 /* ARGSUSED */
1255 int
1256 dsl_destroy_inconsistent(const char *dsname, void *arg)
1257 {
1258         objset_t *os;
1259
1260         if (dmu_objset_hold(dsname, FTAG, &os) == 0) {
1261                 boolean_t need_destroy = DS_IS_INCONSISTENT(dmu_objset_ds(os));
1262
1263                 /*
1264                  * If the dataset is inconsistent because a resumable receive
1265                  * has failed, then do not destroy it.
1266                  */
1267                 if (dsl_dataset_has_resume_receive_state(dmu_objset_ds(os)))
1268                         need_destroy = B_FALSE;
1269
1270                 dmu_objset_rele(os, FTAG);
1271                 if (need_destroy)
1272                         (void) dsl_destroy_head(dsname);
1273         }
1274         return (0);
1275 }
1276
1277
1278 #if defined(_KERNEL)
1279 EXPORT_SYMBOL(dsl_destroy_head);
1280 EXPORT_SYMBOL(dsl_destroy_head_sync_impl);
1281 EXPORT_SYMBOL(dsl_dataset_user_hold_check_one);
1282 EXPORT_SYMBOL(dsl_destroy_snapshot_sync_impl);
1283 EXPORT_SYMBOL(dsl_destroy_inconsistent);
1284 EXPORT_SYMBOL(dsl_dataset_user_release_tmp);
1285 EXPORT_SYMBOL(dsl_destroy_head_check_impl);
1286 #endif