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) 2012, 2015 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  */
  27
  28 #include <sys/zfs_context.h>
  29 #include <sys/dsl_userhold.h>
  30 #include <sys/dsl_dataset.h>
  31 #include <sys/dsl_synctask.h>
  32 #include <sys/dmu_tx.h>
  33 #include <sys/dsl_pool.h>
  34 #include <sys/dsl_dir.h>
  35 #include <sys/dmu_traverse.h>
  36 #include <sys/dsl_scan.h>
  37 #include <sys/dmu_objset.h>
  38 #include <sys/zap.h>
  39 #include <sys/zfeature.h>
  40 #include <sys/zfs_ioctl.h>
  41 #include <sys/dsl_deleg.h>
  42 #include <sys/dmu_impl.h>
  43
  44 typedef struct dmu_snapshots_destroy_arg {
  45         nvlist_t *dsda_snaps;
  46         nvlist_t *dsda_successful_snaps;
  47         boolean_t dsda_defer;
  48         nvlist_t *dsda_errlist;
  49 } dmu_snapshots_destroy_arg_t;
  50
  51 int
  52 dsl_destroy_snapshot_check_impl(dsl_dataset_t *ds, boolean_t defer)
  53 {
  54         if (!ds->ds_is_snapshot)
  55                 return (SET_ERROR(EINVAL));
  56
  57         if (dsl_dataset_long_held(ds))
  58                 return (SET_ERROR(EBUSY));
  59
  60         /*
  61          * Only allow deferred destroy on pools that support it.
  62          * NOTE: deferred destroy is only supported on snapshots.
  63          */
  64         if (defer) {
  65                 if (spa_version(ds->ds_dir->dd_pool->dp_spa) <
  66                     SPA_VERSION_USERREFS)
  67                         return (SET_ERROR(ENOTSUP));
  68                 return (0);
  69         }
  70
  71         /*
  72          * If this snapshot has an elevated user reference count,
  73          * we can't destroy it yet.
  74          */
  75         if (ds->ds_userrefs > 0)
  76                 return (SET_ERROR(EBUSY));
  77
  78         /*
  79          * Can't delete a branch point.
  80          */
  81         if (dsl_dataset_phys(ds)->ds_num_children > 1)
  82                 return (SET_ERROR(EEXIST));
  83
  84         return (0);
  85 }
  86
  87 static int
  88 dsl_destroy_snapshot_check(void *arg, dmu_tx_t *tx)
  89 {
  90         dmu_snapshots_destroy_arg_t *dsda = arg;
  91         dsl_pool_t *dp = dmu_tx_pool(tx);
  92         nvpair_t *pair;
  93         int error = 0;
  94
  95         if (!dmu_tx_is_syncing(tx))
  96                 return (0);
  97
  98         for (pair = nvlist_next_nvpair(dsda->dsda_snaps, NULL);
  99             pair != NULL; pair = nvlist_next_nvpair(dsda->dsda_snaps, pair)) {
 100                 dsl_dataset_t *ds;
 101
 102                 error = dsl_dataset_hold(dp, nvpair_name(pair),
 103                     FTAG, &ds);
 104
 105                 /*
 106                  * If the snapshot does not exist, silently ignore it
 107                  * (it's "already destroyed").
 108                  */
 109                 if (error == ENOENT)
 110                         continue;
 111
 112                 if (error == 0) {
 113                         error = dsl_destroy_snapshot_check_impl(ds,
 114                             dsda->dsda_defer);
 115                         dsl_dataset_rele(ds, FTAG);
 116                 }
 117
 118                 if (error == 0) {
 119                         fnvlist_add_boolean(dsda->dsda_successful_snaps,
 120                             nvpair_name(pair));
 121                 } else {
 122                         fnvlist_add_int32(dsda->dsda_errlist,
 123                             nvpair_name(pair), error);
 124                 }
 125         }
 126
 127         pair = nvlist_next_nvpair(dsda->dsda_errlist, NULL);
 128         if (pair != NULL)
 129                 return (fnvpair_value_int32(pair));
 130
 131         return (0);
 132 }
 133
 134 struct process_old_arg {
 135         dsl_dataset_t *ds;
 136         dsl_dataset_t *ds_prev;
 137         boolean_t after_branch_point;
 138         zio_t *pio;
 139         uint64_t used, comp, uncomp;
 140 };
 141
 142 static int
 143 process_old_cb(void *arg, const blkptr_t *bp, dmu_tx_t *tx)
 144 {
 145         struct process_old_arg *poa = arg;
 146         dsl_pool_t *dp = poa->ds->ds_dir->dd_pool;
 147
 148         ASSERT(!BP_IS_HOLE(bp));
 149
 150         if (bp->blk_birth <= dsl_dataset_phys(poa->ds)->ds_prev_snap_txg) {
 151                 dsl_deadlist_insert(&poa->ds->ds_deadlist, bp, tx);
 152                 if (poa->ds_prev && !poa->after_branch_point &&
 153                     bp->blk_birth >
 154                     dsl_dataset_phys(poa->ds_prev)->ds_prev_snap_txg) {
 155                         dsl_dataset_phys(poa->ds_prev)->ds_unique_bytes +=
 156                             bp_get_dsize_sync(dp->dp_spa, bp);
 157                 }
 158         } else {
 159                 poa->used += bp_get_dsize_sync(dp->dp_spa, bp);
 160                 poa->comp += BP_GET_PSIZE(bp);
 161                 poa->uncomp += BP_GET_UCSIZE(bp);
 162                 dsl_free_sync(poa->pio, dp, tx->tx_txg, bp);
 163         }
 164         return (0);
 165 }
 166
 167 static void
 168 process_old_deadlist(dsl_dataset_t *ds, dsl_dataset_t *ds_prev,
 169     dsl_dataset_t *ds_next, boolean_t after_branch_point, dmu_tx_t *tx)
 170 {
 171         struct process_old_arg poa = { 0 };
 172         dsl_pool_t *dp = ds->ds_dir->dd_pool;
 173         objset_t *mos = dp->dp_meta_objset;
 174         uint64_t deadlist_obj;
 175
 176         ASSERT(ds->ds_deadlist.dl_oldfmt);
 177         ASSERT(ds_next->ds_deadlist.dl_oldfmt);
 178
 179         poa.ds = ds;
 180         poa.ds_prev = ds_prev;
 181         poa.after_branch_point = after_branch_point;
 182         poa.pio = zio_root(dp->dp_spa, NULL, NULL, ZIO_FLAG_MUSTSUCCEED);
 183         VERIFY0(bpobj_iterate(&ds_next->ds_deadlist.dl_bpobj,
 184             process_old_cb, &poa, tx));
 185         VERIFY0(zio_wait(poa.pio));
 186         ASSERT3U(poa.used, ==, dsl_dataset_phys(ds)->ds_unique_bytes);
 187
 188         /* change snapused */
 189         dsl_dir_diduse_space(ds->ds_dir, DD_USED_SNAP,
 190             -poa.used, -poa.comp, -poa.uncomp, tx);
 191
 192         /* swap next's deadlist to our deadlist */
 193         dsl_deadlist_close(&ds->ds_deadlist);
 194         dsl_deadlist_close(&ds_next->ds_deadlist);
 195         deadlist_obj = dsl_dataset_phys(ds)->ds_deadlist_obj;
 196         dsl_dataset_phys(ds)->ds_deadlist_obj =
 197             dsl_dataset_phys(ds_next)->ds_deadlist_obj;
 198         dsl_dataset_phys(ds_next)->ds_deadlist_obj = deadlist_obj;
 199         dsl_deadlist_open(&ds->ds_deadlist, mos,
 200             dsl_dataset_phys(ds)->ds_deadlist_obj);
 201         dsl_deadlist_open(&ds_next->ds_deadlist, mos,
 202             dsl_dataset_phys(ds_next)->ds_deadlist_obj);
 203 }
 204
 205 static void
 206 dsl_dataset_remove_clones_key(dsl_dataset_t *ds, uint64_t mintxg, dmu_tx_t *tx)
 207 {
 208         objset_t *mos = ds->ds_dir->dd_pool->dp_meta_objset;
 209         zap_cursor_t zc;
 210         zap_attribute_t za;
 211
 212         /*
 213          * If it is the old version, dd_clones doesn't exist so we can't
 214          * find the clones, but dsl_deadlist_remove_key() is a no-op so it
 215          * doesn't matter.
 216          */
 217         if (dsl_dir_phys(ds->ds_dir)->dd_clones == 0)
 218                 return;
 219
 220         for (zap_cursor_init(&zc, mos, dsl_dir_phys(ds->ds_dir)->dd_clones);
 221             zap_cursor_retrieve(&zc, &za) == 0;
 222             zap_cursor_advance(&zc)) {
 223                 dsl_dataset_t *clone;
 224
 225                 VERIFY0(dsl_dataset_hold_obj(ds->ds_dir->dd_pool,
 226                     za.za_first_integer, FTAG, &clone));
 227                 if (clone->ds_dir->dd_origin_txg > mintxg) {
 228                         dsl_deadlist_remove_key(&clone->ds_deadlist,
 229                             mintxg, tx);
 230                         dsl_dataset_remove_clones_key(clone, mintxg, tx);
 231                 }
 232                 dsl_dataset_rele(clone, FTAG);
 233         }
 234         zap_cursor_fini(&zc);
 235 }
 236
 237 void
 238 dsl_destroy_snapshot_sync_impl(dsl_dataset_t *ds, boolean_t defer, dmu_tx_t *tx)
 239 {
 240         int err;
 241         int after_branch_point = FALSE;
 242         dsl_pool_t *dp = ds->ds_dir->dd_pool;
 243         objset_t *mos = dp->dp_meta_objset;
 244         dsl_dataset_t *ds_prev = NULL;
 245         uint64_t obj;
 246
 247         ASSERT(RRW_WRITE_HELD(&dp->dp_config_rwlock));
 248         ASSERT3U(dsl_dataset_phys(ds)->ds_bp.blk_birth, <=, tx->tx_txg);
 249         ASSERT(refcount_is_zero(&ds->ds_longholds));
 250
 251         if (defer &&
 252             (ds->ds_userrefs > 0 ||
 253             dsl_dataset_phys(ds)->ds_num_children > 1)) {
 254                 ASSERT(spa_version(dp->dp_spa) >= SPA_VERSION_USERREFS);
 255                 dmu_buf_will_dirty(ds->ds_dbuf, tx);
 256                 dsl_dataset_phys(ds)->ds_flags |= DS_FLAG_DEFER_DESTROY;
 257                 spa_history_log_internal_ds(ds, "defer_destroy", tx, "");
 258                 return;
 259         }
 260
 261         ASSERT3U(dsl_dataset_phys(ds)->ds_num_children, <=, 1);
 262
 263         /* We need to log before removing it from the namespace. */
 264         spa_history_log_internal_ds(ds, "destroy", tx, "");
 265
 266         dsl_scan_ds_destroyed(ds, tx);
 267
 268         obj = ds->ds_object;
 269
 270         for (spa_feature_t f = 0; f < SPA_FEATURES; f++) {
 271                 if (ds->ds_feature_inuse[f]) {
 272                         dsl_dataset_deactivate_feature(obj, f, tx);
 273                         ds->ds_feature_inuse[f] = B_FALSE;
 274                 }
 275         }
 276         if (dsl_dataset_phys(ds)->ds_prev_snap_obj != 0) {
 277                 ASSERT3P(ds->ds_prev, ==, NULL);
 278                 VERIFY0(dsl_dataset_hold_obj(dp,
 279                     dsl_dataset_phys(ds)->ds_prev_snap_obj, FTAG, &ds_prev));
 280                 after_branch_point =
 281                     (dsl_dataset_phys(ds_prev)->ds_next_snap_obj != obj);
 282
 283                 dmu_buf_will_dirty(ds_prev->ds_dbuf, tx);
 284                 if (after_branch_point &&
 285                     dsl_dataset_phys(ds_prev)->ds_next_clones_obj != 0) {
 286                         dsl_dataset_remove_from_next_clones(ds_prev, obj, tx);
 287                         if (dsl_dataset_phys(ds)->ds_next_snap_obj != 0) {
 288                                 VERIFY0(zap_add_int(mos,
 289                                     dsl_dataset_phys(ds_prev)->
 290                                     ds_next_clones_obj,
 291                                     dsl_dataset_phys(ds)->ds_next_snap_obj,
 292                                     tx));
 293                         }
 294                 }
 295                 if (!after_branch_point) {
 296                         dsl_dataset_phys(ds_prev)->ds_next_snap_obj =
 297                             dsl_dataset_phys(ds)->ds_next_snap_obj;
 298                 }
 299         }
 300
 301         dsl_dataset_t *ds_next;
 302         uint64_t old_unique;
 303         uint64_t used = 0, comp = 0, uncomp = 0;
 304
 305         VERIFY0(dsl_dataset_hold_obj(dp,
 306             dsl_dataset_phys(ds)->ds_next_snap_obj, FTAG, &ds_next));
 307         ASSERT3U(dsl_dataset_phys(ds_next)->ds_prev_snap_obj, ==, obj);
 308
 309         old_unique = dsl_dataset_phys(ds_next)->ds_unique_bytes;
 310
 311         dmu_buf_will_dirty(ds_next->ds_dbuf, tx);
 312         dsl_dataset_phys(ds_next)->ds_prev_snap_obj =
 313             dsl_dataset_phys(ds)->ds_prev_snap_obj;
 314         dsl_dataset_phys(ds_next)->ds_prev_snap_txg =
 315             dsl_dataset_phys(ds)->ds_prev_snap_txg;
 316         ASSERT3U(dsl_dataset_phys(ds)->ds_prev_snap_txg, ==,
 317             ds_prev ? dsl_dataset_phys(ds_prev)->ds_creation_txg : 0);
 318
 319         if (ds_next->ds_deadlist.dl_oldfmt) {
 320                 process_old_deadlist(ds, ds_prev, ds_next,
 321                     after_branch_point, tx);
 322         } else {
 323                 /* Adjust prev's unique space. */
 324                 if (ds_prev && !after_branch_point) {
 325                         dsl_deadlist_space_range(&ds_next->ds_deadlist,
 326                             dsl_dataset_phys(ds_prev)->ds_prev_snap_txg,
 327                             dsl_dataset_phys(ds)->ds_prev_snap_txg,
 328                             &used, &comp, &uncomp);
 329                         dsl_dataset_phys(ds_prev)->ds_unique_bytes += used;
 330                 }
 331
 332                 /* Adjust snapused. */
 333                 dsl_deadlist_space_range(&ds_next->ds_deadlist,
 334                     dsl_dataset_phys(ds)->ds_prev_snap_txg, UINT64_MAX,
 335                     &used, &comp, &uncomp);
 336                 dsl_dir_diduse_space(ds->ds_dir, DD_USED_SNAP,
 337                     -used, -comp, -uncomp, tx);
 338
 339                 /* Move blocks to be freed to pool's free list. */
 340                 dsl_deadlist_move_bpobj(&ds_next->ds_deadlist,
 341                     &dp->dp_free_bpobj, dsl_dataset_phys(ds)->ds_prev_snap_txg,
 342                     tx);
 343                 dsl_dir_diduse_space(tx->tx_pool->dp_free_dir,
 344                     DD_USED_HEAD, used, comp, uncomp, tx);
 345
 346                 /* Merge our deadlist into next's and free it. */
 347                 dsl_deadlist_merge(&ds_next->ds_deadlist,
 348                     dsl_dataset_phys(ds)->ds_deadlist_obj, tx);
 349         }
 350         dsl_deadlist_close(&ds->ds_deadlist);
 351         dsl_deadlist_free(mos, dsl_dataset_phys(ds)->ds_deadlist_obj, tx);
 352         dmu_buf_will_dirty(ds->ds_dbuf, tx);
 353         dsl_dataset_phys(ds)->ds_deadlist_obj = 0;
 354
 355         /* Collapse range in clone heads */
 356         dsl_dataset_remove_clones_key(ds,
 357             dsl_dataset_phys(ds)->ds_creation_txg, tx);
 358
 359         if (ds_next->ds_is_snapshot) {
 360                 dsl_dataset_t *ds_nextnext;
 361
 362                 /*
 363                  * Update next's unique to include blocks which
 364                  * were previously shared by only this snapshot
 365                  * and it.  Those blocks will be born after the
 366                  * prev snap and before this snap, and will have
 367                  * died after the next snap and before the one
 368                  * after that (ie. be on the snap after next's
 369                  * deadlist).
 370                  */
 371                 VERIFY0(dsl_dataset_hold_obj(dp,
 372                     dsl_dataset_phys(ds_next)->ds_next_snap_obj,
 373                     FTAG, &ds_nextnext));
 374                 dsl_deadlist_space_range(&ds_nextnext->ds_deadlist,
 375                     dsl_dataset_phys(ds)->ds_prev_snap_txg,
 376                     dsl_dataset_phys(ds)->ds_creation_txg,
 377                     &used, &comp, &uncomp);
 378                 dsl_dataset_phys(ds_next)->ds_unique_bytes += used;
 379                 dsl_dataset_rele(ds_nextnext, FTAG);
 380                 ASSERT3P(ds_next->ds_prev, ==, NULL);
 381
 382                 /* Collapse range in this head. */
 383                 dsl_dataset_t *hds;
 384                 VERIFY0(dsl_dataset_hold_obj(dp,
 385                     dsl_dir_phys(ds->ds_dir)->dd_head_dataset_obj, FTAG, &hds));
 386                 dsl_deadlist_remove_key(&hds->ds_deadlist,
 387                     dsl_dataset_phys(ds)->ds_creation_txg, tx);
 388                 dsl_dataset_rele(hds, FTAG);
 389
 390         } else {
 391                 ASSERT3P(ds_next->ds_prev, ==, ds);
 392                 dsl_dataset_rele(ds_next->ds_prev, ds_next);
 393                 ds_next->ds_prev = NULL;
 394                 if (ds_prev) {
 395                         VERIFY0(dsl_dataset_hold_obj(dp,
 396                             dsl_dataset_phys(ds)->ds_prev_snap_obj,
 397                             ds_next, &ds_next->ds_prev));
 398                 }
 399
 400                 dsl_dataset_recalc_head_uniq(ds_next);
 401
 402                 /*
 403                  * Reduce the amount of our unconsumed refreservation
 404                  * being charged to our parent by the amount of
 405                  * new unique data we have gained.
 406                  */
 407                 if (old_unique < ds_next->ds_reserved) {
 408                         int64_t mrsdelta;
 409                         uint64_t new_unique =
 410                             dsl_dataset_phys(ds_next)->ds_unique_bytes;
 411
 412                         ASSERT(old_unique <= new_unique);
 413                         mrsdelta = MIN(new_unique - old_unique,
 414                             ds_next->ds_reserved - old_unique);
 415                         dsl_dir_diduse_space(ds->ds_dir,
 416                             DD_USED_REFRSRV, -mrsdelta, 0, 0, tx);
 417                 }
 418         }
 419         dsl_dataset_rele(ds_next, FTAG);
 420
 421         /*
 422          * This must be done after the dsl_traverse(), because it will
 423          * re-open the objset.
 424          */
 425         if (ds->ds_objset) {
 426                 dmu_objset_evict(ds->ds_objset);
 427                 ds->ds_objset = NULL;
 428         }
 429
 430         /* remove from snapshot namespace */
 431         dsl_dataset_t *ds_head;
 432         ASSERT(dsl_dataset_phys(ds)->ds_snapnames_zapobj == 0);
 433         VERIFY0(dsl_dataset_hold_obj(dp,
 434             dsl_dir_phys(ds->ds_dir)->dd_head_dataset_obj, FTAG, &ds_head));
 435         VERIFY0(dsl_dataset_get_snapname(ds));
 436 #ifdef ZFS_DEBUG
 437         {
 438                 uint64_t val;
 439
 440                 err = dsl_dataset_snap_lookup(ds_head,
 441                     ds->ds_snapname, &val);
 442                 ASSERT0(err);
 443                 ASSERT3U(val, ==, obj);
 444         }
 445 #endif
 446         VERIFY0(dsl_dataset_snap_remove(ds_head, ds->ds_snapname, tx, B_TRUE));
 447         dsl_dataset_rele(ds_head, FTAG);
 448
 449         if (ds_prev != NULL)
 450                 dsl_dataset_rele(ds_prev, FTAG);
 451
 452         spa_prop_clear_bootfs(dp->dp_spa, ds->ds_object, tx);
 453
 454         if (dsl_dataset_phys(ds)->ds_next_clones_obj != 0) {
 455                 uint64_t count;
 456                 ASSERT0(zap_count(mos,
 457                     dsl_dataset_phys(ds)->ds_next_clones_obj, &count) &&
 458                     count == 0);
 459                 VERIFY0(dmu_object_free(mos,
 460                     dsl_dataset_phys(ds)->ds_next_clones_obj, tx));
 461         }
 462         if (dsl_dataset_phys(ds)->ds_props_obj != 0)
 463                 VERIFY0(zap_destroy(mos, dsl_dataset_phys(ds)->ds_props_obj,
 464                     tx));
 465         if (dsl_dataset_phys(ds)->ds_userrefs_obj != 0)
 466                 VERIFY0(zap_destroy(mos, dsl_dataset_phys(ds)->ds_userrefs_obj,
 467                     tx));
 468         dsl_dir_rele(ds->ds_dir, ds);
 469         ds->ds_dir = NULL;
 470         dmu_object_free_zapified(mos, obj, tx);
 471 }
 472
 473 static void
 474 dsl_destroy_snapshot_sync(void *arg, dmu_tx_t *tx)
 475 {
 476         dmu_snapshots_destroy_arg_t *dsda = arg;
 477         dsl_pool_t *dp = dmu_tx_pool(tx);
 478         nvpair_t *pair;
 479
 480         for (pair = nvlist_next_nvpair(dsda->dsda_successful_snaps, NULL);
 481             pair != NULL;
 482             pair = nvlist_next_nvpair(dsda->dsda_successful_snaps, pair)) {
 483                 dsl_dataset_t *ds;
 484
 485                 VERIFY0(dsl_dataset_hold(dp, nvpair_name(pair), FTAG, &ds));
 486
 487                 dsl_destroy_snapshot_sync_impl(ds, dsda->dsda_defer, tx);
 488                 dsl_dataset_rele(ds, FTAG);
 489         }
 490 }
 491
 492 /*
 493  * The semantics of this function are described in the comment above
 494  * lzc_destroy_snaps().  To summarize:
 495  *
 496  * The snapshots must all be in the same pool.
 497  *
 498  * Snapshots that don't exist will be silently ignored (considered to be
 499  * "already deleted").
 500  *
 501  * On success, all snaps will be destroyed and this will return 0.
 502  * On failure, no snaps will be destroyed, the errlist will be filled in,
 503  * and this will return an errno.
 504  */
 505 int
 506 dsl_destroy_snapshots_nvl(nvlist_t *snaps, boolean_t defer,
 507     nvlist_t *errlist)
 508 {
 509         dmu_snapshots_destroy_arg_t dsda;
 510         int error;
 511         nvpair_t *pair;
 512
 513         pair = nvlist_next_nvpair(snaps, NULL);
 514         if (pair == NULL)
 515                 return (0);
 516
 517         dsda.dsda_snaps = snaps;
 518         dsda.dsda_successful_snaps = fnvlist_alloc();
 519         dsda.dsda_defer = defer;
 520         dsda.dsda_errlist = errlist;
 521
 522         error = dsl_sync_task(nvpair_name(pair),
 523             dsl_destroy_snapshot_check, dsl_destroy_snapshot_sync,
 524             &dsda, 0, ZFS_SPACE_CHECK_NONE);
 525         fnvlist_free(dsda.dsda_successful_snaps);
 526
 527         return (error);
 528 }
 529
 530 int
 531 dsl_destroy_snapshot(const char *name, boolean_t defer)
 532 {
 533         int error;
 534         nvlist_t *nvl = fnvlist_alloc();
 535         nvlist_t *errlist = fnvlist_alloc();
 536
 537         fnvlist_add_boolean(nvl, name);
 538         error = dsl_destroy_snapshots_nvl(nvl, defer, errlist);
 539         fnvlist_free(errlist);
 540         fnvlist_free(nvl);
 541         return (error);
 542 }
 543
 544 struct killarg {
 545         dsl_dataset_t *ds;
 546         dmu_tx_t *tx;
 547 };
 548
 549 /* ARGSUSED */
 550 static int
 551 kill_blkptr(spa_t *spa, zilog_t *zilog, const blkptr_t *bp,
 552     const zbookmark_phys_t *zb, const dnode_phys_t *dnp, void *arg)
 553 {
 554         struct killarg *ka = arg;
 555         dmu_tx_t *tx = ka->tx;
 556
 557         if (bp == NULL || BP_IS_HOLE(bp) || BP_IS_EMBEDDED(bp))
 558                 return (0);
 559
 560         if (zb->zb_level == ZB_ZIL_LEVEL) {
 561                 ASSERT(zilog != NULL);
 562                 /*
 563                  * It's a block in the intent log.  It has no
 564                  * accounting, so just free it.
 565                  */
 566                 dsl_free(ka->tx->tx_pool, ka->tx->tx_txg, bp);
 567         } else {
 568                 ASSERT(zilog == NULL);
 569                 ASSERT3U(bp->blk_birth, >,
 570                     dsl_dataset_phys(ka->ds)->ds_prev_snap_txg);
 571                 (void) dsl_dataset_block_kill(ka->ds, bp, tx, B_FALSE);
 572         }
 573
 574         return (0);
 575 }
 576
 577 static void
 578 old_synchronous_dataset_destroy(dsl_dataset_t *ds, dmu_tx_t *tx)
 579 {
 580         struct killarg ka;
 581
 582         /*
 583          * Free everything that we point to (that's born after
 584          * the previous snapshot, if we are a clone)
 585          *
 586          * NB: this should be very quick, because we already
 587          * freed all the objects in open context.
 588          */
 589         ka.ds = ds;
 590         ka.tx = tx;
 591         VERIFY0(traverse_dataset(ds,
 592             dsl_dataset_phys(ds)->ds_prev_snap_txg, TRAVERSE_POST,
 593             kill_blkptr, &ka));
 594         ASSERT(!DS_UNIQUE_IS_ACCURATE(ds) ||
 595             dsl_dataset_phys(ds)->ds_unique_bytes == 0);
 596 }
 597
 598 typedef struct dsl_destroy_head_arg {
 599         const char *ddha_name;
 600 } dsl_destroy_head_arg_t;
 601
 602 int
 603 dsl_destroy_head_check_impl(dsl_dataset_t *ds, int expected_holds)
 604 {
 605         int error;
 606         uint64_t count;
 607         objset_t *mos;
 608
 609         ASSERT(!ds->ds_is_snapshot);
 610         if (ds->ds_is_snapshot)
 611                 return (SET_ERROR(EINVAL));
 612
 613         if (refcount_count(&ds->ds_longholds) != expected_holds)
 614                 return (SET_ERROR(EBUSY));
 615
 616         mos = ds->ds_dir->dd_pool->dp_meta_objset;
 617
 618         /*
 619          * Can't delete a head dataset if there are snapshots of it.
 620          * (Except if the only snapshots are from the branch we cloned
 621          * from.)
 622          */
 623         if (ds->ds_prev != NULL &&
 624             dsl_dataset_phys(ds->ds_prev)->ds_next_snap_obj == ds->ds_object)
 625                 return (SET_ERROR(EBUSY));
 626
 627         /*
 628          * Can't delete if there are children of this fs.
 629          */
 630         error = zap_count(mos,
 631             dsl_dir_phys(ds->ds_dir)->dd_child_dir_zapobj, &count);
 632         if (error != 0)
 633                 return (error);
 634         if (count != 0)
 635                 return (SET_ERROR(EEXIST));
 636
 637         if (dsl_dir_is_clone(ds->ds_dir) && DS_IS_DEFER_DESTROY(ds->ds_prev) &&
 638             dsl_dataset_phys(ds->ds_prev)->ds_num_children == 2 &&
 639             ds->ds_prev->ds_userrefs == 0) {
 640                 /* We need to remove the origin snapshot as well. */
 641                 if (!refcount_is_zero(&ds->ds_prev->ds_longholds))
 642                         return (SET_ERROR(EBUSY));
 643         }
 644         return (0);
 645 }
 646
 647 static int
 648 dsl_destroy_head_check(void *arg, dmu_tx_t *tx)
 649 {
 650         dsl_destroy_head_arg_t *ddha = arg;
 651         dsl_pool_t *dp = dmu_tx_pool(tx);
 652         dsl_dataset_t *ds;
 653         int error;
 654
 655         error = dsl_dataset_hold(dp, ddha->ddha_name, FTAG, &ds);
 656         if (error != 0)
 657                 return (error);
 658
 659         error = dsl_destroy_head_check_impl(ds, 0);
 660         dsl_dataset_rele(ds, FTAG);
 661         return (error);
 662 }
 663
 664 static void
 665 dsl_dir_destroy_sync(uint64_t ddobj, dmu_tx_t *tx)
 666 {
 667         dsl_dir_t *dd;
 668         dsl_pool_t *dp = dmu_tx_pool(tx);
 669         objset_t *mos = dp->dp_meta_objset;
 670         dd_used_t t;
 671
 672         ASSERT(RRW_WRITE_HELD(&dmu_tx_pool(tx)->dp_config_rwlock));
 673
 674         VERIFY0(dsl_dir_hold_obj(dp, ddobj, NULL, FTAG, &dd));
 675
 676         ASSERT0(dsl_dir_phys(dd)->dd_head_dataset_obj);
 677
 678         /*
 679          * Decrement the filesystem count for all parent filesystems.
 680          *
 681          * When we receive an incremental stream into a filesystem that already
 682          * exists, a temporary clone is created.  We never count this temporary
 683          * clone, whose name begins with a '%'.
 684          */
 685         if (dd->dd_myname[0] != '%' && dd->dd_parent != NULL)
 686                 dsl_fs_ss_count_adjust(dd->dd_parent, -1,
 687                     DD_FIELD_FILESYSTEM_COUNT, tx);
 688
 689         /*
 690          * Remove our reservation. The impl() routine avoids setting the
 691          * actual property, which would require the (already destroyed) ds.
 692          */
 693         dsl_dir_set_reservation_sync_impl(dd, 0, tx);
 694
 695         ASSERT0(dsl_dir_phys(dd)->dd_used_bytes);
 696         ASSERT0(dsl_dir_phys(dd)->dd_reserved);
 697         for (t = 0; t < DD_USED_NUM; t++)
 698                 ASSERT0(dsl_dir_phys(dd)->dd_used_breakdown[t]);
 699
 700         VERIFY0(zap_destroy(mos, dsl_dir_phys(dd)->dd_child_dir_zapobj, tx));
 701         VERIFY0(zap_destroy(mos, dsl_dir_phys(dd)->dd_props_zapobj, tx));
 702         VERIFY0(dsl_deleg_destroy(mos, dsl_dir_phys(dd)->dd_deleg_zapobj, tx));
 703         VERIFY0(zap_remove(mos,
 704             dsl_dir_phys(dd->dd_parent)->dd_child_dir_zapobj,
 705             dd->dd_myname, tx));
 706
 707         dsl_dir_rele(dd, FTAG);
 708         dmu_object_free_zapified(mos, ddobj, tx);
 709 }
 710
 711 void
 712 dsl_destroy_head_sync_impl(dsl_dataset_t *ds, dmu_tx_t *tx)
 713 {
 714         dsl_pool_t *dp = dmu_tx_pool(tx);
 715         objset_t *mos = dp->dp_meta_objset;
 716         uint64_t obj, ddobj, prevobj = 0;
 717         boolean_t rmorigin;
 718
 719         ASSERT3U(dsl_dataset_phys(ds)->ds_num_children, <=, 1);
 720         ASSERT(ds->ds_prev == NULL ||
 721             dsl_dataset_phys(ds->ds_prev)->ds_next_snap_obj != ds->ds_object);
 722         ASSERT3U(dsl_dataset_phys(ds)->ds_bp.blk_birth, <=, tx->tx_txg);
 723         ASSERT(RRW_WRITE_HELD(&dp->dp_config_rwlock));
 724
 725         /* We need to log before removing it from the namespace. */
 726         spa_history_log_internal_ds(ds, "destroy", tx, "");
 727
 728         rmorigin = (dsl_dir_is_clone(ds->ds_dir) &&
 729             DS_IS_DEFER_DESTROY(ds->ds_prev) &&
 730             dsl_dataset_phys(ds->ds_prev)->ds_num_children == 2 &&
 731             ds->ds_prev->ds_userrefs == 0);
 732
 733         /* Remove our reservation. */
 734         if (ds->ds_reserved != 0) {
 735                 dsl_dataset_set_refreservation_sync_impl(ds,
 736                     (ZPROP_SRC_NONE | ZPROP_SRC_LOCAL | ZPROP_SRC_RECEIVED),
 737                     0, tx);
 738                 ASSERT0(ds->ds_reserved);
 739         }
 740
 741         obj = ds->ds_object;
 742
 743         for (spa_feature_t f = 0; f < SPA_FEATURES; f++) {
 744                 if (ds->ds_feature_inuse[f]) {
 745                         dsl_dataset_deactivate_feature(obj, f, tx);
 746                         ds->ds_feature_inuse[f] = B_FALSE;
 747                 }
 748         }
 749
 750         dsl_scan_ds_destroyed(ds, tx);
 751
 752         if (dsl_dataset_phys(ds)->ds_prev_snap_obj != 0) {
 753                 /* This is a clone */
 754                 ASSERT(ds->ds_prev != NULL);
 755                 ASSERT3U(dsl_dataset_phys(ds->ds_prev)->ds_next_snap_obj, !=,
 756                     obj);
 757                 ASSERT0(dsl_dataset_phys(ds)->ds_next_snap_obj);
 758
 759                 dmu_buf_will_dirty(ds->ds_prev->ds_dbuf, tx);
 760                 if (dsl_dataset_phys(ds->ds_prev)->ds_next_clones_obj != 0) {
 761                         dsl_dataset_remove_from_next_clones(ds->ds_prev,
 762                             obj, tx);
 763                 }
 764
 765                 ASSERT3U(dsl_dataset_phys(ds->ds_prev)->ds_num_children, >, 1);
 766                 dsl_dataset_phys(ds->ds_prev)->ds_num_children--;
 767         }
 768
 769         /*
 770          * Destroy the deadlist.  Unless it's a clone, the
 771          * deadlist should be empty.  (If it's a clone, it's
 772          * safe to ignore the deadlist contents.)
 773          */
 774         dsl_deadlist_close(&ds->ds_deadlist);
 775         dsl_deadlist_free(mos, dsl_dataset_phys(ds)->ds_deadlist_obj, tx);
 776         dmu_buf_will_dirty(ds->ds_dbuf, tx);
 777         dsl_dataset_phys(ds)->ds_deadlist_obj = 0;
 778
 779         objset_t *os;
 780         VERIFY0(dmu_objset_from_ds(ds, &os));
 781
 782         if (!spa_feature_is_enabled(dp->dp_spa, SPA_FEATURE_ASYNC_DESTROY)) {
 783                 old_synchronous_dataset_destroy(ds, tx);
 784         } else {
 785                 /*
 786                  * Move the bptree into the pool's list of trees to
 787                  * clean up and update space accounting information.
 788                  */
 789                 uint64_t used, comp, uncomp;
 790
 791                 zil_destroy_sync(dmu_objset_zil(os), tx);
 792
 793                 if (!spa_feature_is_active(dp->dp_spa,
 794                     SPA_FEATURE_ASYNC_DESTROY)) {
 795                         dsl_scan_t *scn = dp->dp_scan;
 796                         spa_feature_incr(dp->dp_spa, SPA_FEATURE_ASYNC_DESTROY,
 797                             tx);
 798                         dp->dp_bptree_obj = bptree_alloc(mos, tx);
 799                         VERIFY0(zap_add(mos,
 800                             DMU_POOL_DIRECTORY_OBJECT,
 801                             DMU_POOL_BPTREE_OBJ, sizeof (uint64_t), 1,
 802                             &dp->dp_bptree_obj, tx));
 803                         ASSERT(!scn->scn_async_destroying);
 804                         scn->scn_async_destroying = B_TRUE;
 805                 }
 806
 807                 used = dsl_dir_phys(ds->ds_dir)->dd_used_bytes;
 808                 comp = dsl_dir_phys(ds->ds_dir)->dd_compressed_bytes;
 809                 uncomp = dsl_dir_phys(ds->ds_dir)->dd_uncompressed_bytes;
 810
 811                 ASSERT(!DS_UNIQUE_IS_ACCURATE(ds) ||
 812                     dsl_dataset_phys(ds)->ds_unique_bytes == used);
 813
 814                 bptree_add(mos, dp->dp_bptree_obj,
 815                     &dsl_dataset_phys(ds)->ds_bp,
 816                     dsl_dataset_phys(ds)->ds_prev_snap_txg,
 817                     used, comp, uncomp, tx);
 818                 dsl_dir_diduse_space(ds->ds_dir, DD_USED_HEAD,
 819                     -used, -comp, -uncomp, tx);
 820                 dsl_dir_diduse_space(dp->dp_free_dir, DD_USED_HEAD,
 821                     used, comp, uncomp, tx);
 822         }
 823
 824         if (ds->ds_prev != NULL) {
 825                 if (spa_version(dp->dp_spa) >= SPA_VERSION_DIR_CLONES) {
 826                         VERIFY0(zap_remove_int(mos,
 827                             dsl_dir_phys(ds->ds_prev->ds_dir)->dd_clones,
 828                             ds->ds_object, tx));
 829                 }
 830                 prevobj = ds->ds_prev->ds_object;
 831                 dsl_dataset_rele(ds->ds_prev, ds);
 832                 ds->ds_prev = NULL;
 833         }
 834
 835         /*
 836          * This must be done after the dsl_traverse(), because it will
 837          * re-open the objset.
 838          */
 839         if (ds->ds_objset) {
 840                 dmu_objset_evict(ds->ds_objset);
 841                 ds->ds_objset = NULL;
 842         }
 843
 844         /* Erase the link in the dir */
 845         dmu_buf_will_dirty(ds->ds_dir->dd_dbuf, tx);
 846         dsl_dir_phys(ds->ds_dir)->dd_head_dataset_obj = 0;
 847         ddobj = ds->ds_dir->dd_object;
 848         ASSERT(dsl_dataset_phys(ds)->ds_snapnames_zapobj != 0);
 849         VERIFY0(zap_destroy(mos,
 850             dsl_dataset_phys(ds)->ds_snapnames_zapobj, tx));
 851
 852         if (ds->ds_bookmarks != 0) {
 853                 VERIFY0(zap_destroy(mos, ds->ds_bookmarks, tx));
 854                 spa_feature_decr(dp->dp_spa, SPA_FEATURE_BOOKMARKS, tx);
 855         }
 856
 857         spa_prop_clear_bootfs(dp->dp_spa, ds->ds_object, tx);
 858
 859         ASSERT0(dsl_dataset_phys(ds)->ds_next_clones_obj);
 860         ASSERT0(dsl_dataset_phys(ds)->ds_props_obj);
 861         ASSERT0(dsl_dataset_phys(ds)->ds_userrefs_obj);
 862         dsl_dir_rele(ds->ds_dir, ds);
 863         ds->ds_dir = NULL;
 864         dmu_object_free_zapified(mos, obj, tx);
 865
 866         dsl_dir_destroy_sync(ddobj, tx);
 867
 868         if (rmorigin) {
 869                 dsl_dataset_t *prev;
 870                 VERIFY0(dsl_dataset_hold_obj(dp, prevobj, FTAG, &prev));
 871                 dsl_destroy_snapshot_sync_impl(prev, B_FALSE, tx);
 872                 dsl_dataset_rele(prev, FTAG);
 873         }
 874 }
 875
 876 static void
 877 dsl_destroy_head_sync(void *arg, dmu_tx_t *tx)
 878 {
 879         dsl_destroy_head_arg_t *ddha = arg;
 880         dsl_pool_t *dp = dmu_tx_pool(tx);
 881         dsl_dataset_t *ds;
 882
 883         VERIFY0(dsl_dataset_hold(dp, ddha->ddha_name, FTAG, &ds));
 884         dsl_destroy_head_sync_impl(ds, tx);
 885         dsl_dataset_rele(ds, FTAG);
 886 }
 887
 888 static void
 889 dsl_destroy_head_begin_sync(void *arg, dmu_tx_t *tx)
 890 {
 891         dsl_destroy_head_arg_t *ddha = arg;
 892         dsl_pool_t *dp = dmu_tx_pool(tx);
 893         dsl_dataset_t *ds;
 894
 895         VERIFY0(dsl_dataset_hold(dp, ddha->ddha_name, FTAG, &ds));
 896
 897         /* Mark it as inconsistent on-disk, in case we crash */
 898         dmu_buf_will_dirty(ds->ds_dbuf, tx);
 899         dsl_dataset_phys(ds)->ds_flags |= DS_FLAG_INCONSISTENT;
 900
 901         spa_history_log_internal_ds(ds, "destroy begin", tx, "");
 902         dsl_dataset_rele(ds, FTAG);
 903 }
 904
 905 int
 906 dsl_destroy_head(const char *name)
 907 {
 908         dsl_destroy_head_arg_t ddha;
 909         int error;
 910         spa_t *spa;
 911         boolean_t isenabled;
 912
 913 #ifdef _KERNEL
 914         zfs_destroy_unmount_origin(name);
 915 #endif
 916
 917         error = spa_open(name, &spa, FTAG);
 918         if (error != 0)
 919                 return (error);
 920         isenabled = spa_feature_is_enabled(spa, SPA_FEATURE_ASYNC_DESTROY);
 921         spa_close(spa, FTAG);
 922
 923         ddha.ddha_name = name;
 924
 925         if (!isenabled) {
 926                 objset_t *os;
 927
 928                 error = dsl_sync_task(name, dsl_destroy_head_check,
 929                     dsl_destroy_head_begin_sync, &ddha,
 930                     0, ZFS_SPACE_CHECK_NONE);
 931                 if (error != 0)
 932                         return (error);
 933
 934                 /*
 935                  * Head deletion is processed in one txg on old pools;
 936                  * remove the objects from open context so that the txg sync
 937                  * is not too long.
 938                  */
 939                 error = dmu_objset_own(name, DMU_OST_ANY, B_FALSE, FTAG, &os);
 940                 if (error == 0) {
 941                         uint64_t prev_snap_txg =
 942                             dsl_dataset_phys(dmu_objset_ds(os))->
 943                             ds_prev_snap_txg;
 944                         for (uint64_t obj = 0; error == 0;
 945                             error = dmu_object_next(os, &obj, FALSE,
 946                             prev_snap_txg))
 947                                 (void) dmu_free_long_object(os, obj);
 948                         /* sync out all frees */
 949                         txg_wait_synced(dmu_objset_pool(os), 0);
 950                         dmu_objset_disown(os, FTAG);
 951                 }
 952         }
 953
 954         return (dsl_sync_task(name, dsl_destroy_head_check,
 955             dsl_destroy_head_sync, &ddha, 0, ZFS_SPACE_CHECK_NONE));
 956 }
 957
 958 /*
 959  * Note, this function is used as the callback for dmu_objset_find().  We
 960  * always return 0 so that we will continue to find and process
 961  * inconsistent datasets, even if we encounter an error trying to
 962  * process one of them.
 963  */
 964 /* ARGSUSED */
 965 int
 966 dsl_destroy_inconsistent(const char *dsname, void *arg)
 967 {
 968         objset_t *os;
 969
 970         if (dmu_objset_hold(dsname, FTAG, &os) == 0) {
 971                 boolean_t need_destroy = DS_IS_INCONSISTENT(dmu_objset_ds(os));
 972
 973                 /*
 974                  * If the dataset is inconsistent because a resumable receive
 975                  * has failed, then do not destroy it.
 976                  */
 977                 if (dsl_dataset_has_resume_receive_state(dmu_objset_ds(os)))
 978                         need_destroy = B_FALSE;
 979
 980                 dmu_objset_rele(os, FTAG);
 981                 if (need_destroy)
 982                         (void) dsl_destroy_head(dsname);
 983         }
 984         return (0);
 985 }