1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21 /*
  22  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
  23  * Copyright (c) 2011, 2015 by Delphix. All rights reserved.
  24  * Copyright (c) 2014, Joyent, Inc. All rights reserved.
  25  * Copyright (c) 2014 RackTop Systems.
  26  * Copyright (c) 2014 Spectra Logic Corporation, All rights reserved.
  27  */
  28 
  29 #include <sys/dmu_objset.h>
  30 #include <sys/dsl_dataset.h>
  31 #include <sys/dsl_dir.h>
  32 #include <sys/dsl_prop.h>
  33 #include <sys/dsl_synctask.h>
  34 #include <sys/dmu_traverse.h>
  35 #include <sys/dmu_impl.h>
  36 #include <sys/dmu_tx.h>
  37 #include <sys/arc.h>
  38 #include <sys/zio.h>
  39 #include <sys/zap.h>
  40 #include <sys/zfeature.h>
  41 #include <sys/unique.h>
  42 #include <sys/zfs_context.h>
  43 #include <sys/zfs_ioctl.h>
  44 #include <sys/spa.h>
  45 #include <sys/zfs_znode.h>
  46 #include <sys/zfs_onexit.h>
  47 #include <sys/zvol.h>
  48 #include <sys/dsl_scan.h>
  49 #include <sys/dsl_deadlist.h>
  50 #include <sys/dsl_destroy.h>
  51 #include <sys/dsl_userhold.h>
  52 #include <sys/dsl_bookmark.h>
  53 #include <sys/dmu_send.h>
  54 #include <sys/zio_checksum.h>
  55 #include <sys/zio_compress.h>
  56 #include <zfs_fletcher.h>
  57 
  58 /*
  59  * The SPA supports block sizes up to 16MB.  However, very large blocks
  60  * can have an impact on i/o latency (e.g. tying up a spinning disk for
  61  * ~300ms), and also potentially on the memory allocator.  Therefore,
  62  * we do not allow the recordsize to be set larger than zfs_max_recordsize
  63  * (default 1MB).  Larger blocks can be created by changing this tunable,
  64  * and pools with larger blocks can always be imported and used, regardless
  65  * of this setting.
  66  */
  67 int zfs_max_recordsize = 1 * 1024 * 1024;
  68 
  69 #define SWITCH64(x, y) \
  70         { \
  71                 uint64_t __tmp = (x); \
  72                 (x) = (y); \
  73                 (y) = __tmp; \
  74         }
  75 
  76 #define DS_REF_MAX      (1ULL << 62)
  77 
  78 extern inline dsl_dataset_phys_t *dsl_dataset_phys(dsl_dataset_t *ds);
  79 
  80 /*
  81  * Figure out how much of this delta should be propogated to the dsl_dir
  82  * layer.  If there's a refreservation, that space has already been
  83  * partially accounted for in our ancestors.
  84  */
  85 static int64_t
  86 parent_delta(dsl_dataset_t *ds, int64_t delta)
  87 {
  88         dsl_dataset_phys_t *ds_phys;
  89         uint64_t old_bytes, new_bytes;
  90 
  91         if (ds->ds_reserved == 0)
  92                 return (delta);
  93 
  94         ds_phys = dsl_dataset_phys(ds);
  95         old_bytes = MAX(ds_phys->ds_unique_bytes, ds->ds_reserved);
  96         new_bytes = MAX(ds_phys->ds_unique_bytes + delta, ds->ds_reserved);
  97 
  98         ASSERT3U(ABS((int64_t)(new_bytes - old_bytes)), <=, ABS(delta));
  99         return (new_bytes - old_bytes);
 100 }
 101 
 102 void
 103 dsl_dataset_block_born(dsl_dataset_t *ds, const blkptr_t *bp, dmu_tx_t *tx)
 104 {
 105         int used = bp_get_dsize_sync(tx->tx_pool->dp_spa, bp);
 106         int compressed = BP_GET_PSIZE(bp);
 107         int uncompressed = BP_GET_UCSIZE(bp);
 108         int64_t delta;
 109 
 110         dprintf_bp(bp, "ds=%p", ds);
 111 
 112         ASSERT(dmu_tx_is_syncing(tx));
 113         /* It could have been compressed away to nothing */
 114         if (BP_IS_HOLE(bp))
 115                 return;
 116         ASSERT(BP_GET_TYPE(bp) != DMU_OT_NONE);
 117         ASSERT(DMU_OT_IS_VALID(BP_GET_TYPE(bp)));
 118         if (ds == NULL) {
 119                 dsl_pool_mos_diduse_space(tx->tx_pool,
 120                     used, compressed, uncompressed);
 121                 return;
 122         }
 123 
 124         dmu_buf_will_dirty(ds->ds_dbuf, tx);
 125         mutex_enter(&ds->ds_lock);
 126         delta = parent_delta(ds, used);
 127         dsl_dataset_phys(ds)->ds_referenced_bytes += used;
 128         dsl_dataset_phys(ds)->ds_compressed_bytes += compressed;
 129         dsl_dataset_phys(ds)->ds_uncompressed_bytes += uncompressed;
 130         dsl_dataset_phys(ds)->ds_unique_bytes += used;
 131 
 132         if (BP_GET_LSIZE(bp) > SPA_OLD_MAXBLOCKSIZE) {
 133                 ds->ds_feature_activation_needed[SPA_FEATURE_LARGE_BLOCKS] =
 134                     B_TRUE;
 135         }
 136 
 137         spa_feature_t f = zio_checksum_to_feature(BP_GET_CHECKSUM(bp));
 138         if (f != SPA_FEATURE_NONE)
 139                 ds->ds_feature_activation_needed[f] = B_TRUE;
 140 
 141         mutex_exit(&ds->ds_lock);
 142         dsl_dir_diduse_space(ds->ds_dir, DD_USED_HEAD, delta,
 143             compressed, uncompressed, tx);
 144         dsl_dir_transfer_space(ds->ds_dir, used - delta,
 145             DD_USED_REFRSRV, DD_USED_HEAD, tx);
 146 }
 147 
 148 int
 149 dsl_dataset_block_kill(dsl_dataset_t *ds, const blkptr_t *bp, dmu_tx_t *tx,
 150     boolean_t async)
 151 {
 152         int used = bp_get_dsize_sync(tx->tx_pool->dp_spa, bp);
 153         int compressed = BP_GET_PSIZE(bp);
 154         int uncompressed = BP_GET_UCSIZE(bp);
 155 
 156         if (BP_IS_HOLE(bp))
 157                 return (0);
 158 
 159         ASSERT(dmu_tx_is_syncing(tx));
 160         ASSERT(bp->blk_birth <= tx->tx_txg);
 161 
 162         if (ds == NULL) {
 163                 dsl_free(tx->tx_pool, tx->tx_txg, bp);
 164                 dsl_pool_mos_diduse_space(tx->tx_pool,
 165                     -used, -compressed, -uncompressed);
 166                 return (used);
 167         }
 168         ASSERT3P(tx->tx_pool, ==, ds->ds_dir->dd_pool);
 169 
 170         ASSERT(!ds->ds_is_snapshot);
 171         dmu_buf_will_dirty(ds->ds_dbuf, tx);
 172 
 173         if (bp->blk_birth > dsl_dataset_phys(ds)->ds_prev_snap_txg) {
 174                 int64_t delta;
 175 
 176                 dprintf_bp(bp, "freeing ds=%llu", ds->ds_object);
 177                 dsl_free(tx->tx_pool, tx->tx_txg, bp);
 178 
 179                 mutex_enter(&ds->ds_lock);
 180                 ASSERT(dsl_dataset_phys(ds)->ds_unique_bytes >= used ||
 181                     !DS_UNIQUE_IS_ACCURATE(ds));
 182                 delta = parent_delta(ds, -used);
 183                 dsl_dataset_phys(ds)->ds_unique_bytes -= used;
 184                 mutex_exit(&ds->ds_lock);
 185                 dsl_dir_diduse_space(ds->ds_dir, DD_USED_HEAD,
 186                     delta, -compressed, -uncompressed, tx);
 187                 dsl_dir_transfer_space(ds->ds_dir, -used - delta,
 188                     DD_USED_REFRSRV, DD_USED_HEAD, tx);
 189         } else {
 190                 dprintf_bp(bp, "putting on dead list: %s", "");
 191                 if (async) {
 192                         /*
 193                          * We are here as part of zio's write done callback,
 194                          * which means we're a zio interrupt thread.  We can't
 195                          * call dsl_deadlist_insert() now because it may block
 196                          * waiting for I/O.  Instead, put bp on the deferred
 197                          * queue and let dsl_pool_sync() finish the job.
 198                          */
 199                         bplist_append(&ds->ds_pending_deadlist, bp);
 200                 } else {
 201                         dsl_deadlist_insert(&ds->ds_deadlist, bp, tx);
 202                 }
 203                 ASSERT3U(ds->ds_prev->ds_object, ==,
 204                     dsl_dataset_phys(ds)->ds_prev_snap_obj);
 205                 ASSERT(dsl_dataset_phys(ds->ds_prev)->ds_num_children > 0);
 206                 /* if (bp->blk_birth > prev prev snap txg) prev unique += bs */
 207                 if (dsl_dataset_phys(ds->ds_prev)->ds_next_snap_obj ==
 208                     ds->ds_object && bp->blk_birth >
 209                     dsl_dataset_phys(ds->ds_prev)->ds_prev_snap_txg) {
 210                         dmu_buf_will_dirty(ds->ds_prev->ds_dbuf, tx);
 211                         mutex_enter(&ds->ds_prev->ds_lock);
 212                         dsl_dataset_phys(ds->ds_prev)->ds_unique_bytes += used;
 213                         mutex_exit(&ds->ds_prev->ds_lock);
 214                 }
 215                 if (bp->blk_birth > ds->ds_dir->dd_origin_txg) {
 216                         dsl_dir_transfer_space(ds->ds_dir, used,
 217                             DD_USED_HEAD, DD_USED_SNAP, tx);
 218                 }
 219         }
 220         mutex_enter(&ds->ds_lock);
 221         ASSERT3U(dsl_dataset_phys(ds)->ds_referenced_bytes, >=, used);
 222         dsl_dataset_phys(ds)->ds_referenced_bytes -= used;
 223         ASSERT3U(dsl_dataset_phys(ds)->ds_compressed_bytes, >=, compressed);
 224         dsl_dataset_phys(ds)->ds_compressed_bytes -= compressed;
 225         ASSERT3U(dsl_dataset_phys(ds)->ds_uncompressed_bytes, >=, uncompressed);
 226         dsl_dataset_phys(ds)->ds_uncompressed_bytes -= uncompressed;
 227         mutex_exit(&ds->ds_lock);
 228 
 229         return (used);
 230 }
 231 
 232 uint64_t
 233 dsl_dataset_prev_snap_txg(dsl_dataset_t *ds)
 234 {
 235         uint64_t trysnap = 0;
 236 
 237         if (ds == NULL)
 238                 return (0);
 239         /*
 240          * The snapshot creation could fail, but that would cause an
 241          * incorrect FALSE return, which would only result in an
 242          * overestimation of the amount of space that an operation would
 243          * consume, which is OK.
 244          *
 245          * There's also a small window where we could miss a pending
 246          * snapshot, because we could set the sync task in the quiescing
 247          * phase.  So this should only be used as a guess.
 248          */
 249         if (ds->ds_trysnap_txg >
 250             spa_last_synced_txg(ds->ds_dir->dd_pool->dp_spa))
 251                 trysnap = ds->ds_trysnap_txg;
 252         return (MAX(dsl_dataset_phys(ds)->ds_prev_snap_txg, trysnap));
 253 }
 254 
 255 boolean_t
 256 dsl_dataset_block_freeable(dsl_dataset_t *ds, const blkptr_t *bp,
 257     uint64_t blk_birth)
 258 {
 259         if (blk_birth <= dsl_dataset_prev_snap_txg(ds) ||
 260             (bp != NULL && BP_IS_HOLE(bp)))
 261                 return (B_FALSE);
 262 
 263         ddt_prefetch(dsl_dataset_get_spa(ds), bp);
 264 
 265         return (B_TRUE);
 266 }
 267 
 268 static void
 269 dsl_dataset_evict(void *dbu)
 270 {
 271         dsl_dataset_t *ds = dbu;
 272 
 273         ASSERT(ds->ds_owner == NULL);
 274 
 275         ds->ds_dbuf = NULL;
 276 
 277         unique_remove(ds->ds_fsid_guid);
 278 
 279         if (ds->ds_objset != NULL)
 280                 dmu_objset_evict(ds->ds_objset);
 281 
 282         if (ds->ds_prev) {
 283                 dsl_dataset_rele(ds->ds_prev, ds);
 284                 ds->ds_prev = NULL;
 285         }
 286 
 287         bplist_destroy(&ds->ds_pending_deadlist);
 288         if (ds->ds_deadlist.dl_os != NULL)
 289                 dsl_deadlist_close(&ds->ds_deadlist);
 290         if (ds->ds_dir)
 291                 dsl_dir_async_rele(ds->ds_dir, ds);
 292 
 293         ASSERT(!list_link_active(&ds->ds_synced_link));
 294 
 295         list_destroy(&ds->ds_prop_cbs);
 296         mutex_destroy(&ds->ds_lock);
 297         mutex_destroy(&ds->ds_opening_lock);
 298         mutex_destroy(&ds->ds_sendstream_lock);
 299         refcount_destroy(&ds->ds_longholds);
 300 
 301         kmem_free(ds, sizeof (dsl_dataset_t));
 302 }
 303 
 304 int
 305 dsl_dataset_get_snapname(dsl_dataset_t *ds)
 306 {
 307         dsl_dataset_phys_t *headphys;
 308         int err;
 309         dmu_buf_t *headdbuf;
 310         dsl_pool_t *dp = ds->ds_dir->dd_pool;
 311         objset_t *mos = dp->dp_meta_objset;
 312 
 313         if (ds->ds_snapname[0])
 314                 return (0);
 315         if (dsl_dataset_phys(ds)->ds_next_snap_obj == 0)
 316                 return (0);
 317 
 318         err = dmu_bonus_hold(mos, dsl_dir_phys(ds->ds_dir)->dd_head_dataset_obj,
 319             FTAG, &headdbuf);
 320         if (err != 0)
 321                 return (err);
 322         headphys = headdbuf->db_data;
 323         err = zap_value_search(dp->dp_meta_objset,
 324             headphys->ds_snapnames_zapobj, ds->ds_object, 0, ds->ds_snapname);
 325         dmu_buf_rele(headdbuf, FTAG);
 326         return (err);
 327 }
 328 
 329 int
 330 dsl_dataset_snap_lookup(dsl_dataset_t *ds, const char *name, uint64_t *value)
 331 {
 332         objset_t *mos = ds->ds_dir->dd_pool->dp_meta_objset;
 333         uint64_t snapobj = dsl_dataset_phys(ds)->ds_snapnames_zapobj;
 334         matchtype_t mt;
 335         int err;
 336 
 337         if (dsl_dataset_phys(ds)->ds_flags & DS_FLAG_CI_DATASET)
 338                 mt = MT_FIRST;
 339         else
 340                 mt = MT_EXACT;
 341 
 342         err = zap_lookup_norm(mos, snapobj, name, 8, 1,
 343             value, mt, NULL, 0, NULL);
 344         if (err == ENOTSUP && mt == MT_FIRST)
 345                 err = zap_lookup(mos, snapobj, name, 8, 1, value);
 346         return (err);
 347 }
 348 
 349 int
 350 dsl_dataset_snap_remove(dsl_dataset_t *ds, const char *name, dmu_tx_t *tx,
 351     boolean_t adj_cnt)
 352 {
 353         objset_t *mos = ds->ds_dir->dd_pool->dp_meta_objset;
 354         uint64_t snapobj = dsl_dataset_phys(ds)->ds_snapnames_zapobj;
 355         matchtype_t mt;
 356         int err;
 357 
 358         dsl_dir_snap_cmtime_update(ds->ds_dir);
 359 
 360         if (dsl_dataset_phys(ds)->ds_flags & DS_FLAG_CI_DATASET)
 361                 mt = MT_FIRST;
 362         else
 363                 mt = MT_EXACT;
 364 
 365         err = zap_remove_norm(mos, snapobj, name, mt, tx);
 366         if (err == ENOTSUP && mt == MT_FIRST)
 367                 err = zap_remove(mos, snapobj, name, tx);
 368 
 369         if (err == 0 && adj_cnt)
 370                 dsl_fs_ss_count_adjust(ds->ds_dir, -1,
 371                     DD_FIELD_SNAPSHOT_COUNT, tx);
 372 
 373         return (err);
 374 }
 375 
 376 boolean_t
 377 dsl_dataset_try_add_ref(dsl_pool_t *dp, dsl_dataset_t *ds, void *tag)
 378 {
 379         dmu_buf_t *dbuf = ds->ds_dbuf;
 380         boolean_t result = B_FALSE;
 381 
 382         if (dbuf != NULL && dmu_buf_try_add_ref(dbuf, dp->dp_meta_objset,
 383             ds->ds_object, DMU_BONUS_BLKID, tag)) {
 384 
 385                 if (ds == dmu_buf_get_user(dbuf))
 386                         result = B_TRUE;
 387                 else
 388                         dmu_buf_rele(dbuf, tag);
 389         }
 390 
 391         return (result);
 392 }
 393 
 394 int
 395 dsl_dataset_hold_obj(dsl_pool_t *dp, uint64_t dsobj, void *tag,
 396     dsl_dataset_t **dsp)
 397 {
 398         objset_t *mos = dp->dp_meta_objset;
 399         dmu_buf_t *dbuf;
 400         dsl_dataset_t *ds;
 401         int err;
 402         dmu_object_info_t doi;
 403 
 404         ASSERT(dsl_pool_config_held(dp));
 405 
 406         err = dmu_bonus_hold(mos, dsobj, tag, &dbuf);
 407         if (err != 0)
 408                 return (err);
 409 
 410         /* Make sure dsobj has the correct object type. */
 411         dmu_object_info_from_db(dbuf, &doi);
 412         if (doi.doi_bonus_type != DMU_OT_DSL_DATASET) {
 413                 dmu_buf_rele(dbuf, tag);
 414                 return (SET_ERROR(EINVAL));
 415         }
 416 
 417         ds = dmu_buf_get_user(dbuf);
 418         if (ds == NULL) {
 419                 dsl_dataset_t *winner = NULL;
 420 
 421                 ds = kmem_zalloc(sizeof (dsl_dataset_t), KM_SLEEP);
 422                 ds->ds_dbuf = dbuf;
 423                 ds->ds_object = dsobj;
 424                 ds->ds_is_snapshot = dsl_dataset_phys(ds)->ds_num_children != 0;
 425 
 426                 mutex_init(&ds->ds_lock, NULL, MUTEX_DEFAULT, NULL);
 427                 mutex_init(&ds->ds_opening_lock, NULL, MUTEX_DEFAULT, NULL);
 428                 mutex_init(&ds->ds_sendstream_lock, NULL, MUTEX_DEFAULT, NULL);
 429                 refcount_create(&ds->ds_longholds);
 430 
 431                 bplist_create(&ds->ds_pending_deadlist);
 432                 dsl_deadlist_open(&ds->ds_deadlist,
 433                     mos, dsl_dataset_phys(ds)->ds_deadlist_obj);
 434 
 435                 list_create(&ds->ds_sendstreams, sizeof (dmu_sendarg_t),
 436                     offsetof(dmu_sendarg_t, dsa_link));
 437 
 438                 list_create(&ds->ds_prop_cbs, sizeof (dsl_prop_cb_record_t),
 439                     offsetof(dsl_prop_cb_record_t, cbr_ds_node));
 440 
 441                 if (doi.doi_type == DMU_OTN_ZAP_METADATA) {
 442                         for (spa_feature_t f = 0; f < SPA_FEATURES; f++) {
 443                                 if (!(spa_feature_table[f].fi_flags &
 444                                     ZFEATURE_FLAG_PER_DATASET))
 445                                         continue;
 446                                 err = zap_contains(mos, dsobj,
 447                                     spa_feature_table[f].fi_guid);
 448                                 if (err == 0) {
 449                                         ds->ds_feature_inuse[f] = B_TRUE;
 450                                 } else {
 451                                         ASSERT3U(err, ==, ENOENT);
 452                                         err = 0;
 453                                 }
 454                         }
 455                 }
 456 
 457                 err = dsl_dir_hold_obj(dp,
 458                     dsl_dataset_phys(ds)->ds_dir_obj, NULL, ds, &ds->ds_dir);
 459                 if (err != 0) {
 460                         mutex_destroy(&ds->ds_lock);
 461                         mutex_destroy(&ds->ds_opening_lock);
 462                         mutex_destroy(&ds->ds_sendstream_lock);
 463                         refcount_destroy(&ds->ds_longholds);
 464                         bplist_destroy(&ds->ds_pending_deadlist);
 465                         dsl_deadlist_close(&ds->ds_deadlist);
 466                         kmem_free(ds, sizeof (dsl_dataset_t));
 467                         dmu_buf_rele(dbuf, tag);
 468                         return (err);
 469                 }
 470 
 471                 if (!ds->ds_is_snapshot) {
 472                         ds->ds_snapname[0] = '\0';
 473                         if (dsl_dataset_phys(ds)->ds_prev_snap_obj != 0) {
 474                                 err = dsl_dataset_hold_obj(dp,
 475                                     dsl_dataset_phys(ds)->ds_prev_snap_obj,
 476                                     ds, &ds->ds_prev);
 477                         }
 478                         if (doi.doi_type == DMU_OTN_ZAP_METADATA) {
 479                                 int zaperr = zap_lookup(mos, ds->ds_object,
 480                                     DS_FIELD_BOOKMARK_NAMES,
 481                                     sizeof (ds->ds_bookmarks), 1,
 482                                     &ds->ds_bookmarks);
 483                                 if (zaperr != ENOENT)
 484                                         VERIFY0(zaperr);
 485                         }
 486                 } else {
 487                         if (zfs_flags & ZFS_DEBUG_SNAPNAMES)
 488                                 err = dsl_dataset_get_snapname(ds);
 489                         if (err == 0 &&
 490                             dsl_dataset_phys(ds)->ds_userrefs_obj != 0) {
 491                                 err = zap_count(
 492                                     ds->ds_dir->dd_pool->dp_meta_objset,
 493                                     dsl_dataset_phys(ds)->ds_userrefs_obj,
 494                                     &ds->ds_userrefs);
 495                         }
 496                 }
 497 
 498                 if (err == 0 && !ds->ds_is_snapshot) {
 499                         err = dsl_prop_get_int_ds(ds,
 500                             zfs_prop_to_name(ZFS_PROP_REFRESERVATION),
 501                             &ds->ds_reserved);
 502                         if (err == 0) {
 503                                 err = dsl_prop_get_int_ds(ds,
 504                                     zfs_prop_to_name(ZFS_PROP_REFQUOTA),
 505                                     &ds->ds_quota);
 506                         }
 507                 } else {
 508                         ds->ds_reserved = ds->ds_quota = 0;
 509                 }
 510 
 511                 dmu_buf_init_user(&ds->ds_dbu, dsl_dataset_evict, &ds->ds_dbuf);
 512                 if (err == 0)
 513                         winner = dmu_buf_set_user_ie(dbuf, &ds->ds_dbu);
 514 
 515                 if (err != 0 || winner != NULL) {
 516                         bplist_destroy(&ds->ds_pending_deadlist);
 517                         dsl_deadlist_close(&ds->ds_deadlist);
 518                         if (ds->ds_prev)
 519                                 dsl_dataset_rele(ds->ds_prev, ds);
 520                         dsl_dir_rele(ds->ds_dir, ds);
 521                         mutex_destroy(&ds->ds_lock);
 522                         mutex_destroy(&ds->ds_opening_lock);
 523                         mutex_destroy(&ds->ds_sendstream_lock);
 524                         refcount_destroy(&ds->ds_longholds);
 525                         kmem_free(ds, sizeof (dsl_dataset_t));
 526                         if (err != 0) {
 527                                 dmu_buf_rele(dbuf, tag);
 528                                 return (err);
 529                         }
 530                         ds = winner;
 531                 } else {
 532                         ds->ds_fsid_guid =
 533                             unique_insert(dsl_dataset_phys(ds)->ds_fsid_guid);
 534                 }
 535         }
 536         ASSERT3P(ds->ds_dbuf, ==, dbuf);
 537         ASSERT3P(dsl_dataset_phys(ds), ==, dbuf->db_data);
 538         ASSERT(dsl_dataset_phys(ds)->ds_prev_snap_obj != 0 ||
 539             spa_version(dp->dp_spa) < SPA_VERSION_ORIGIN ||
 540             dp->dp_origin_snap == NULL || ds == dp->dp_origin_snap);
 541         *dsp = ds;
 542         return (0);
 543 }
 544 
 545 int
 546 dsl_dataset_hold(dsl_pool_t *dp, const char *name,
 547     void *tag, dsl_dataset_t **dsp)
 548 {
 549         dsl_dir_t *dd;
 550         const char *snapname;
 551         uint64_t obj;
 552         int err = 0;
 553         dsl_dataset_t *ds;
 554 
 555         err = dsl_dir_hold(dp, name, FTAG, &dd, &snapname);
 556         if (err != 0)
 557                 return (err);
 558 
 559         ASSERT(dsl_pool_config_held(dp));
 560         obj = dsl_dir_phys(dd)->dd_head_dataset_obj;
 561         if (obj != 0)
 562                 err = dsl_dataset_hold_obj(dp, obj, tag, &ds);
 563         else
 564                 err = SET_ERROR(ENOENT);
 565 
 566         /* we may be looking for a snapshot */
 567         if (err == 0 && snapname != NULL) {
 568                 dsl_dataset_t *snap_ds;
 569 
 570                 if (*snapname++ != '@') {
 571                         dsl_dataset_rele(ds, tag);
 572                         dsl_dir_rele(dd, FTAG);
 573                         return (SET_ERROR(ENOENT));
 574                 }
 575 
 576                 dprintf("looking for snapshot '%s'\n", snapname);
 577                 err = dsl_dataset_snap_lookup(ds, snapname, &obj);
 578                 if (err == 0)
 579                         err = dsl_dataset_hold_obj(dp, obj, tag, &snap_ds);
 580                 dsl_dataset_rele(ds, tag);
 581 
 582                 if (err == 0) {
 583                         mutex_enter(&snap_ds->ds_lock);
 584                         if (snap_ds->ds_snapname[0] == 0)
 585                                 (void) strlcpy(snap_ds->ds_snapname, snapname,
 586                                     sizeof (snap_ds->ds_snapname));
 587                         mutex_exit(&snap_ds->ds_lock);
 588                         ds = snap_ds;
 589                 }
 590         }
 591         if (err == 0)
 592                 *dsp = ds;
 593         dsl_dir_rele(dd, FTAG);
 594         return (err);
 595 }
 596 
 597 int
 598 dsl_dataset_own_obj(dsl_pool_t *dp, uint64_t dsobj,
 599     void *tag, dsl_dataset_t **dsp)
 600 {
 601         int err = dsl_dataset_hold_obj(dp, dsobj, tag, dsp);
 602         if (err != 0)
 603                 return (err);
 604         if (!dsl_dataset_tryown(*dsp, tag)) {
 605                 dsl_dataset_rele(*dsp, tag);
 606                 *dsp = NULL;
 607                 return (SET_ERROR(EBUSY));
 608         }
 609         return (0);
 610 }
 611 
 612 int
 613 dsl_dataset_own(dsl_pool_t *dp, const char *name,
 614     void *tag, dsl_dataset_t **dsp)
 615 {
 616         int err = dsl_dataset_hold(dp, name, tag, dsp);
 617         if (err != 0)
 618                 return (err);
 619         if (!dsl_dataset_tryown(*dsp, tag)) {
 620                 dsl_dataset_rele(*dsp, tag);
 621                 return (SET_ERROR(EBUSY));
 622         }
 623         return (0);
 624 }
 625 
 626 /*
 627  * See the comment above dsl_pool_hold() for details.  In summary, a long
 628  * hold is used to prevent destruction of a dataset while the pool hold
 629  * is dropped, allowing other concurrent operations (e.g. spa_sync()).
 630  *
 631  * The dataset and pool must be held when this function is called.  After it
 632  * is called, the pool hold may be released while the dataset is still held
 633  * and accessed.
 634  */
 635 void
 636 dsl_dataset_long_hold(dsl_dataset_t *ds, void *tag)
 637 {
 638         ASSERT(dsl_pool_config_held(ds->ds_dir->dd_pool));
 639         (void) refcount_add(&ds->ds_longholds, tag);
 640 }
 641 
 642 void
 643 dsl_dataset_long_rele(dsl_dataset_t *ds, void *tag)
 644 {
 645         (void) refcount_remove(&ds->ds_longholds, tag);
 646 }
 647 
 648 /* Return B_TRUE if there are any long holds on this dataset. */
 649 boolean_t
 650 dsl_dataset_long_held(dsl_dataset_t *ds)
 651 {
 652         return (!refcount_is_zero(&ds->ds_longholds));
 653 }
 654 
 655 void
 656 dsl_dataset_name(dsl_dataset_t *ds, char *name)
 657 {
 658         if (ds == NULL) {
 659                 (void) strcpy(name, "mos");
 660         } else {
 661                 dsl_dir_name(ds->ds_dir, name);
 662                 VERIFY0(dsl_dataset_get_snapname(ds));
 663                 if (ds->ds_snapname[0]) {
 664                         (void) strcat(name, "@");
 665                         /*
 666                          * We use a "recursive" mutex so that we
 667                          * can call dprintf_ds() with ds_lock held.
 668                          */
 669                         if (!MUTEX_HELD(&ds->ds_lock)) {
 670                                 mutex_enter(&ds->ds_lock);
 671                                 VERIFY3U(strlen(name) +
 672                                          strlen(ds->ds_snapname) + 1, <=,
 673                                          ZFS_MAXNAMELEN);
 674                                 (void) strcat(name, ds->ds_snapname);
 675                                 mutex_exit(&ds->ds_lock);
 676                         } else {
 677                                 VERIFY3U(strlen(name) +
 678                                          strlen(ds->ds_snapname) + 1, <=,
 679                                          ZFS_MAXNAMELEN);
 680                                 (void) strcat(name, ds->ds_snapname);
 681                         }
 682                 }
 683         }
 684 }
 685 
 686 void
 687 dsl_dataset_rele(dsl_dataset_t *ds, void *tag)
 688 {
 689         dmu_buf_rele(ds->ds_dbuf, tag);
 690 }
 691 
 692 void
 693 dsl_dataset_disown(dsl_dataset_t *ds, void *tag)
 694 {
 695         ASSERT3P(ds->ds_owner, ==, tag);
 696         ASSERT(ds->ds_dbuf != NULL);
 697 
 698         mutex_enter(&ds->ds_lock);
 699         ds->ds_owner = NULL;
 700         mutex_exit(&ds->ds_lock);
 701         dsl_dataset_long_rele(ds, tag);
 702         dsl_dataset_rele(ds, tag);
 703 }
 704 
 705 boolean_t
 706 dsl_dataset_tryown(dsl_dataset_t *ds, void *tag)
 707 {
 708         boolean_t gotit = FALSE;
 709 
 710         ASSERT(dsl_pool_config_held(ds->ds_dir->dd_pool));
 711         mutex_enter(&ds->ds_lock);
 712         if (ds->ds_owner == NULL && !DS_IS_INCONSISTENT(ds)) {
 713                 ds->ds_owner = tag;
 714                 dsl_dataset_long_hold(ds, tag);
 715                 gotit = TRUE;
 716         }
 717         mutex_exit(&ds->ds_lock);
 718         return (gotit);
 719 }
 720 
 721 boolean_t
 722 dsl_dataset_has_owner(dsl_dataset_t *ds)
 723 {
 724         boolean_t rv;
 725         mutex_enter(&ds->ds_lock);
 726         rv = (ds->ds_owner != NULL);
 727         mutex_exit(&ds->ds_lock);
 728         return (rv);
 729 }
 730 
 731 static void
 732 dsl_dataset_activate_feature(uint64_t dsobj, spa_feature_t f, dmu_tx_t *tx)
 733 {
 734         spa_t *spa = dmu_tx_pool(tx)->dp_spa;
 735         objset_t *mos = dmu_tx_pool(tx)->dp_meta_objset;
 736         uint64_t zero = 0;
 737 
 738         VERIFY(spa_feature_table[f].fi_flags & ZFEATURE_FLAG_PER_DATASET);
 739 
 740         spa_feature_incr(spa, f, tx);
 741         dmu_object_zapify(mos, dsobj, DMU_OT_DSL_DATASET, tx);
 742 
 743         VERIFY0(zap_add(mos, dsobj, spa_feature_table[f].fi_guid,
 744             sizeof (zero), 1, &zero, tx));
 745 }
 746 
 747 void
 748 dsl_dataset_deactivate_feature(uint64_t dsobj, spa_feature_t f, dmu_tx_t *tx)
 749 {
 750         spa_t *spa = dmu_tx_pool(tx)->dp_spa;
 751         objset_t *mos = dmu_tx_pool(tx)->dp_meta_objset;
 752 
 753         VERIFY(spa_feature_table[f].fi_flags & ZFEATURE_FLAG_PER_DATASET);
 754 
 755         VERIFY0(zap_remove(mos, dsobj, spa_feature_table[f].fi_guid, tx));
 756         spa_feature_decr(spa, f, tx);
 757 }
 758 
 759 uint64_t
 760 dsl_dataset_create_sync_dd(dsl_dir_t *dd, dsl_dataset_t *origin,
 761     uint64_t flags, dmu_tx_t *tx)
 762 {
 763         dsl_pool_t *dp = dd->dd_pool;
 764         dmu_buf_t *dbuf;
 765         dsl_dataset_phys_t *dsphys;
 766         uint64_t dsobj;
 767         objset_t *mos = dp->dp_meta_objset;
 768 
 769         if (origin == NULL)
 770                 origin = dp->dp_origin_snap;
 771 
 772         ASSERT(origin == NULL || origin->ds_dir->dd_pool == dp);
 773         ASSERT(origin == NULL || dsl_dataset_phys(origin)->ds_num_children > 0);
 774         ASSERT(dmu_tx_is_syncing(tx));
 775         ASSERT(dsl_dir_phys(dd)->dd_head_dataset_obj == 0);
 776 
 777         dsobj = dmu_object_alloc(mos, DMU_OT_DSL_DATASET, 0,
 778             DMU_OT_DSL_DATASET, sizeof (dsl_dataset_phys_t), tx);
 779         VERIFY0(dmu_bonus_hold(mos, dsobj, FTAG, &dbuf));
 780         dmu_buf_will_dirty(dbuf, tx);
 781         dsphys = dbuf->db_data;
 782         bzero(dsphys, sizeof (dsl_dataset_phys_t));
 783         dsphys->ds_dir_obj = dd->dd_object;
 784         dsphys->ds_flags = flags;
 785         dsphys->ds_fsid_guid = unique_create();
 786         (void) random_get_pseudo_bytes((void*)&dsphys->ds_guid,
 787             sizeof (dsphys->ds_guid));
 788         dsphys->ds_snapnames_zapobj =
 789             zap_create_norm(mos, U8_TEXTPREP_TOUPPER, DMU_OT_DSL_DS_SNAP_MAP,
 790             DMU_OT_NONE, 0, tx);
 791         dsphys->ds_creation_time = gethrestime_sec();
 792         dsphys->ds_creation_txg = tx->tx_txg == TXG_INITIAL ? 1 : tx->tx_txg;
 793 
 794         if (origin == NULL) {
 795                 dsphys->ds_deadlist_obj = dsl_deadlist_alloc(mos, tx);
 796         } else {
 797                 dsl_dataset_t *ohds; /* head of the origin snapshot */
 798 
 799                 dsphys->ds_prev_snap_obj = origin->ds_object;
 800                 dsphys->ds_prev_snap_txg =
 801                     dsl_dataset_phys(origin)->ds_creation_txg;
 802                 dsphys->ds_referenced_bytes =
 803                     dsl_dataset_phys(origin)->ds_referenced_bytes;
 804                 dsphys->ds_compressed_bytes =
 805                     dsl_dataset_phys(origin)->ds_compressed_bytes;
 806                 dsphys->ds_uncompressed_bytes =
 807                     dsl_dataset_phys(origin)->ds_uncompressed_bytes;
 808                 dsphys->ds_bp = dsl_dataset_phys(origin)->ds_bp;
 809 
 810                 /*
 811                  * Inherit flags that describe the dataset's contents
 812                  * (INCONSISTENT) or properties (Case Insensitive).
 813                  */
 814                 dsphys->ds_flags |= dsl_dataset_phys(origin)->ds_flags &
 815                     (DS_FLAG_INCONSISTENT | DS_FLAG_CI_DATASET);
 816 
 817                 for (spa_feature_t f = 0; f < SPA_FEATURES; f++) {
 818                         if (origin->ds_feature_inuse[f])
 819                                 dsl_dataset_activate_feature(dsobj, f, tx);
 820                 }
 821 
 822                 dmu_buf_will_dirty(origin->ds_dbuf, tx);
 823                 dsl_dataset_phys(origin)->ds_num_children++;
 824 
 825                 VERIFY0(dsl_dataset_hold_obj(dp,
 826                     dsl_dir_phys(origin->ds_dir)->dd_head_dataset_obj,
 827                     FTAG, &ohds));
 828                 dsphys->ds_deadlist_obj = dsl_deadlist_clone(&ohds->ds_deadlist,
 829                     dsphys->ds_prev_snap_txg, dsphys->ds_prev_snap_obj, tx);
 830                 dsl_dataset_rele(ohds, FTAG);
 831 
 832                 if (spa_version(dp->dp_spa) >= SPA_VERSION_NEXT_CLONES) {
 833                         if (dsl_dataset_phys(origin)->ds_next_clones_obj == 0) {
 834                                 dsl_dataset_phys(origin)->ds_next_clones_obj =
 835                                     zap_create(mos,
 836                                     DMU_OT_NEXT_CLONES, DMU_OT_NONE, 0, tx);
 837                         }
 838                         VERIFY0(zap_add_int(mos,
 839                             dsl_dataset_phys(origin)->ds_next_clones_obj,
 840                             dsobj, tx));
 841                 }
 842 
 843                 dmu_buf_will_dirty(dd->dd_dbuf, tx);
 844                 dsl_dir_phys(dd)->dd_origin_obj = origin->ds_object;
 845                 if (spa_version(dp->dp_spa) >= SPA_VERSION_DIR_CLONES) {
 846                         if (dsl_dir_phys(origin->ds_dir)->dd_clones == 0) {
 847                                 dmu_buf_will_dirty(origin->ds_dir->dd_dbuf, tx);
 848                                 dsl_dir_phys(origin->ds_dir)->dd_clones =
 849                                     zap_create(mos,
 850                                     DMU_OT_DSL_CLONES, DMU_OT_NONE, 0, tx);
 851                         }
 852                         VERIFY0(zap_add_int(mos,
 853                             dsl_dir_phys(origin->ds_dir)->dd_clones,
 854                             dsobj, tx));
 855                 }
 856         }
 857 
 858         if (spa_version(dp->dp_spa) >= SPA_VERSION_UNIQUE_ACCURATE)
 859                 dsphys->ds_flags |= DS_FLAG_UNIQUE_ACCURATE;
 860 
 861         dmu_buf_rele(dbuf, FTAG);
 862 
 863         dmu_buf_will_dirty(dd->dd_dbuf, tx);
 864         dsl_dir_phys(dd)->dd_head_dataset_obj = dsobj;
 865 
 866         return (dsobj);
 867 }
 868 
 869 static void
 870 dsl_dataset_zero_zil(dsl_dataset_t *ds, dmu_tx_t *tx)
 871 {
 872         objset_t *os;
 873 
 874         VERIFY0(dmu_objset_from_ds(ds, &os));
 875         bzero(&os->os_zil_header, sizeof (os->os_zil_header));
 876         dsl_dataset_dirty(ds, tx);
 877 }
 878 
 879 uint64_t
 880 dsl_dataset_create_sync(dsl_dir_t *pdd, const char *lastname,
 881     dsl_dataset_t *origin, uint64_t flags, cred_t *cr, dmu_tx_t *tx)
 882 {
 883         dsl_pool_t *dp = pdd->dd_pool;
 884         uint64_t dsobj, ddobj;
 885         dsl_dir_t *dd;
 886 
 887         ASSERT(dmu_tx_is_syncing(tx));
 888         ASSERT(lastname[0] != '@');
 889 
 890         ddobj = dsl_dir_create_sync(dp, pdd, lastname, tx);
 891         VERIFY0(dsl_dir_hold_obj(dp, ddobj, lastname, FTAG, &dd));
 892 
 893         dsobj = dsl_dataset_create_sync_dd(dd, origin,
 894             flags & ~DS_CREATE_FLAG_NODIRTY, tx);
 895 
 896         dsl_deleg_set_create_perms(dd, tx, cr);
 897 
 898         /*
 899          * Since we're creating a new node we know it's a leaf, so we can
 900          * initialize the counts if the limit feature is active.
 901          */
 902         if (spa_feature_is_active(dp->dp_spa, SPA_FEATURE_FS_SS_LIMIT)) {
 903                 uint64_t cnt = 0;
 904                 objset_t *os = dd->dd_pool->dp_meta_objset;
 905 
 906                 dsl_dir_zapify(dd, tx);
 907                 VERIFY0(zap_add(os, dd->dd_object, DD_FIELD_FILESYSTEM_COUNT,
 908                     sizeof (cnt), 1, &cnt, tx));
 909                 VERIFY0(zap_add(os, dd->dd_object, DD_FIELD_SNAPSHOT_COUNT,
 910                     sizeof (cnt), 1, &cnt, tx));
 911         }
 912 
 913         dsl_dir_rele(dd, FTAG);
 914 
 915         /*
 916          * If we are creating a clone, make sure we zero out any stale
 917          * data from the origin snapshots zil header.
 918          */
 919         if (origin != NULL && !(flags & DS_CREATE_FLAG_NODIRTY)) {
 920                 dsl_dataset_t *ds;
 921 
 922                 VERIFY0(dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds));
 923                 dsl_dataset_zero_zil(ds, tx);
 924                 dsl_dataset_rele(ds, FTAG);
 925         }
 926 
 927         return (dsobj);
 928 }
 929 
 930 /*
 931  * The unique space in the head dataset can be calculated by subtracting
 932  * the space used in the most recent snapshot, that is still being used
 933  * in this file system, from the space currently in use.  To figure out
 934  * the space in the most recent snapshot still in use, we need to take
 935  * the total space used in the snapshot and subtract out the space that
 936  * has been freed up since the snapshot was taken.
 937  */
 938 void
 939 dsl_dataset_recalc_head_uniq(dsl_dataset_t *ds)
 940 {
 941         uint64_t mrs_used;
 942         uint64_t dlused, dlcomp, dluncomp;
 943 
 944         ASSERT(!ds->ds_is_snapshot);
 945 
 946         if (dsl_dataset_phys(ds)->ds_prev_snap_obj != 0)
 947                 mrs_used = dsl_dataset_phys(ds->ds_prev)->ds_referenced_bytes;
 948         else
 949                 mrs_used = 0;
 950 
 951         dsl_deadlist_space(&ds->ds_deadlist, &dlused, &dlcomp, &dluncomp);
 952 
 953         ASSERT3U(dlused, <=, mrs_used);
 954         dsl_dataset_phys(ds)->ds_unique_bytes =
 955             dsl_dataset_phys(ds)->ds_referenced_bytes - (mrs_used - dlused);
 956 
 957         if (spa_version(ds->ds_dir->dd_pool->dp_spa) >=
 958             SPA_VERSION_UNIQUE_ACCURATE)
 959                 dsl_dataset_phys(ds)->ds_flags |= DS_FLAG_UNIQUE_ACCURATE;
 960 }
 961 
 962 void
 963 dsl_dataset_remove_from_next_clones(dsl_dataset_t *ds, uint64_t obj,
 964     dmu_tx_t *tx)
 965 {
 966         objset_t *mos = ds->ds_dir->dd_pool->dp_meta_objset;
 967         uint64_t count;
 968         int err;
 969 
 970         ASSERT(dsl_dataset_phys(ds)->ds_num_children >= 2);
 971         err = zap_remove_int(mos, dsl_dataset_phys(ds)->ds_next_clones_obj,
 972             obj, tx);
 973         /*
 974          * The err should not be ENOENT, but a bug in a previous version
 975          * of the code could cause upgrade_clones_cb() to not set
 976          * ds_next_snap_obj when it should, leading to a missing entry.
 977          * If we knew that the pool was created after
 978          * SPA_VERSION_NEXT_CLONES, we could assert that it isn't
 979          * ENOENT.  However, at least we can check that we don't have
 980          * too many entries in the next_clones_obj even after failing to
 981          * remove this one.
 982          */
 983         if (err != ENOENT)
 984                 VERIFY0(err);
 985         ASSERT0(zap_count(mos, dsl_dataset_phys(ds)->ds_next_clones_obj,
 986             &count));
 987         ASSERT3U(count, <=, dsl_dataset_phys(ds)->ds_num_children - 2);
 988 }
 989 
 990 
 991 blkptr_t *
 992 dsl_dataset_get_blkptr(dsl_dataset_t *ds)
 993 {
 994         return (&dsl_dataset_phys(ds)->ds_bp);
 995 }
 996 
 997 void
 998 dsl_dataset_set_blkptr(dsl_dataset_t *ds, blkptr_t *bp, dmu_tx_t *tx)
 999 {
1000         ASSERT(dmu_tx_is_syncing(tx));
1001         /* If it's the meta-objset, set dp_meta_rootbp */
1002         if (ds == NULL) {
1003                 tx->tx_pool->dp_meta_rootbp = *bp;
1004         } else {
1005                 dmu_buf_will_dirty(ds->ds_dbuf, tx);
1006                 dsl_dataset_phys(ds)->ds_bp = *bp;
1007         }
1008 }
1009 
1010 spa_t *
1011 dsl_dataset_get_spa(dsl_dataset_t *ds)
1012 {
1013         return (ds->ds_dir->dd_pool->dp_spa);
1014 }
1015 
1016 void
1017 dsl_dataset_dirty(dsl_dataset_t *ds, dmu_tx_t *tx)
1018 {
1019         dsl_pool_t *dp;
1020 
1021         if (ds == NULL) /* this is the meta-objset */
1022                 return;
1023 
1024         ASSERT(ds->ds_objset != NULL);
1025 
1026         if (dsl_dataset_phys(ds)->ds_next_snap_obj != 0)
1027                 panic("dirtying snapshot!");
1028 
1029         dp = ds->ds_dir->dd_pool;
1030 
1031         if (txg_list_add(&dp->dp_dirty_datasets, ds, tx->tx_txg)) {
1032                 /* up the hold count until we can be written out */
1033                 dmu_buf_add_ref(ds->ds_dbuf, ds);
1034         }
1035 }
1036 
1037 boolean_t
1038 dsl_dataset_is_dirty(dsl_dataset_t *ds)
1039 {
1040         for (int t = 0; t < TXG_SIZE; t++) {
1041                 if (txg_list_member(&ds->ds_dir->dd_pool->dp_dirty_datasets,
1042                     ds, t))
1043                         return (B_TRUE);
1044         }
1045         return (B_FALSE);
1046 }
1047 
1048 static int
1049 dsl_dataset_snapshot_reserve_space(dsl_dataset_t *ds, dmu_tx_t *tx)
1050 {
1051         uint64_t asize;
1052 
1053         if (!dmu_tx_is_syncing(tx))
1054                 return (0);
1055 
1056         /*
1057          * If there's an fs-only reservation, any blocks that might become
1058          * owned by the snapshot dataset must be accommodated by space
1059          * outside of the reservation.
1060          */
1061         ASSERT(ds->ds_reserved == 0 || DS_UNIQUE_IS_ACCURATE(ds));
1062         asize = MIN(dsl_dataset_phys(ds)->ds_unique_bytes, ds->ds_reserved);
1063         if (asize > dsl_dir_space_available(ds->ds_dir, NULL, 0, TRUE))
1064                 return (SET_ERROR(ENOSPC));
1065 
1066         /*
1067          * Propagate any reserved space for this snapshot to other
1068          * snapshot checks in this sync group.
1069          */
1070         if (asize > 0)
1071                 dsl_dir_willuse_space(ds->ds_dir, asize, tx);
1072 
1073         return (0);
1074 }
1075 
1076 typedef struct dsl_dataset_snapshot_arg {
1077         nvlist_t *ddsa_snaps;
1078         nvlist_t *ddsa_props;
1079         nvlist_t *ddsa_errors;
1080         cred_t *ddsa_cr;
1081 } dsl_dataset_snapshot_arg_t;
1082 
1083 int
1084 dsl_dataset_snapshot_check_impl(dsl_dataset_t *ds, const char *snapname,
1085     dmu_tx_t *tx, boolean_t recv, uint64_t cnt, cred_t *cr)
1086 {
1087         int error;
1088         uint64_t value;
1089 
1090         ds->ds_trysnap_txg = tx->tx_txg;
1091 
1092         if (!dmu_tx_is_syncing(tx))
1093                 return (0);
1094 
1095         /*
1096          * We don't allow multiple snapshots of the same txg.  If there
1097          * is already one, try again.
1098          */
1099         if (dsl_dataset_phys(ds)->ds_prev_snap_txg >= tx->tx_txg)
1100                 return (SET_ERROR(EAGAIN));
1101 
1102         /*
1103          * Check for conflicting snapshot name.
1104          */
1105         error = dsl_dataset_snap_lookup(ds, snapname, &value);
1106         if (error == 0)
1107                 return (SET_ERROR(EEXIST));
1108         if (error != ENOENT)
1109                 return (error);
1110 
1111         /*
1112          * We don't allow taking snapshots of inconsistent datasets, such as
1113          * those into which we are currently receiving.  However, if we are
1114          * creating this snapshot as part of a receive, this check will be
1115          * executed atomically with respect to the completion of the receive
1116          * itself but prior to the clearing of DS_FLAG_INCONSISTENT; in this
1117          * case we ignore this, knowing it will be fixed up for us shortly in
1118          * dmu_recv_end_sync().
1119          */
1120         if (!recv && DS_IS_INCONSISTENT(ds))
1121                 return (SET_ERROR(EBUSY));
1122 
1123         /*
1124          * Skip the check for temporary snapshots or if we have already checked
1125          * the counts in dsl_dataset_snapshot_check. This means we really only
1126          * check the count here when we're receiving a stream.
1127          */
1128         if (cnt != 0 && cr != NULL) {
1129                 error = dsl_fs_ss_limit_check(ds->ds_dir, cnt,
1130                     ZFS_PROP_SNAPSHOT_LIMIT, NULL, cr);
1131                 if (error != 0)
1132                         return (error);
1133         }
1134 
1135         error = dsl_dataset_snapshot_reserve_space(ds, tx);
1136         if (error != 0)
1137                 return (error);
1138 
1139         return (0);
1140 }
1141 
1142 static int
1143 dsl_dataset_snapshot_check(void *arg, dmu_tx_t *tx)
1144 {
1145         dsl_dataset_snapshot_arg_t *ddsa = arg;
1146         dsl_pool_t *dp = dmu_tx_pool(tx);
1147         nvpair_t *pair;
1148         int rv = 0;
1149 
1150         /*
1151          * Pre-compute how many total new snapshots will be created for each
1152          * level in the tree and below. This is needed for validating the
1153          * snapshot limit when either taking a recursive snapshot or when
1154          * taking multiple snapshots.
1155          *
1156          * The problem is that the counts are not actually adjusted when
1157          * we are checking, only when we finally sync. For a single snapshot,
1158          * this is easy, the count will increase by 1 at each node up the tree,
1159          * but its more complicated for the recursive/multiple snapshot case.
1160          *
1161          * The dsl_fs_ss_limit_check function does recursively check the count
1162          * at each level up the tree but since it is validating each snapshot
1163          * independently we need to be sure that we are validating the complete
1164          * count for the entire set of snapshots. We do this by rolling up the
1165          * counts for each component of the name into an nvlist and then
1166          * checking each of those cases with the aggregated count.
1167          *
1168          * This approach properly handles not only the recursive snapshot
1169          * case (where we get all of those on the ddsa_snaps list) but also
1170          * the sibling case (e.g. snapshot a/b and a/c so that we will also
1171          * validate the limit on 'a' using a count of 2).
1172          *
1173          * We validate the snapshot names in the third loop and only report
1174          * name errors once.
1175          */
1176         if (dmu_tx_is_syncing(tx)) {
1177                 nvlist_t *cnt_track = NULL;
1178                 cnt_track = fnvlist_alloc();
1179 
1180                 /* Rollup aggregated counts into the cnt_track list */
1181                 for (pair = nvlist_next_nvpair(ddsa->ddsa_snaps, NULL);
1182                     pair != NULL;
1183                     pair = nvlist_next_nvpair(ddsa->ddsa_snaps, pair)) {
1184                         char *pdelim;
1185                         uint64_t val;
1186                         char nm[MAXPATHLEN];
1187 
1188                         (void) strlcpy(nm, nvpair_name(pair), sizeof (nm));
1189                         pdelim = strchr(nm, '@');
1190                         if (pdelim == NULL)
1191                                 continue;
1192                         *pdelim = '\0';
1193 
1194                         do {
1195                                 if (nvlist_lookup_uint64(cnt_track, nm,
1196                                     &val) == 0) {
1197                                         /* update existing entry */
1198                                         fnvlist_add_uint64(cnt_track, nm,
1199                                             val + 1);
1200                                 } else {
1201                                         /* add to list */
1202                                         fnvlist_add_uint64(cnt_track, nm, 1);
1203                                 }
1204 
1205                                 pdelim = strrchr(nm, '/');
1206                                 if (pdelim != NULL)
1207                                         *pdelim = '\0';
1208                         } while (pdelim != NULL);
1209                 }
1210 
1211                 /* Check aggregated counts at each level */
1212                 for (pair = nvlist_next_nvpair(cnt_track, NULL);
1213                     pair != NULL; pair = nvlist_next_nvpair(cnt_track, pair)) {
1214                         int error = 0;
1215                         char *name;
1216                         uint64_t cnt = 0;
1217                         dsl_dataset_t *ds;
1218 
1219                         name = nvpair_name(pair);
1220                         cnt = fnvpair_value_uint64(pair);
1221                         ASSERT(cnt > 0);
1222 
1223                         error = dsl_dataset_hold(dp, name, FTAG, &ds);
1224                         if (error == 0) {
1225                                 error = dsl_fs_ss_limit_check(ds->ds_dir, cnt,
1226                                     ZFS_PROP_SNAPSHOT_LIMIT, NULL,
1227                                     ddsa->ddsa_cr);
1228                                 dsl_dataset_rele(ds, FTAG);
1229                         }
1230 
1231                         if (error != 0) {
1232                                 if (ddsa->ddsa_errors != NULL)
1233                                         fnvlist_add_int32(ddsa->ddsa_errors,
1234                                             name, error);
1235                                 rv = error;
1236                                 /* only report one error for this check */
1237                                 break;
1238                         }
1239                 }
1240                 nvlist_free(cnt_track);
1241         }
1242 
1243         for (pair = nvlist_next_nvpair(ddsa->ddsa_snaps, NULL);
1244             pair != NULL; pair = nvlist_next_nvpair(ddsa->ddsa_snaps, pair)) {
1245                 int error = 0;
1246                 dsl_dataset_t *ds;
1247                 char *name, *atp;
1248                 char dsname[MAXNAMELEN];
1249 
1250                 name = nvpair_name(pair);
1251                 if (strlen(name) >= MAXNAMELEN)
1252                         error = SET_ERROR(ENAMETOOLONG);
1253                 if (error == 0) {
1254                         atp = strchr(name, '@');
1255                         if (atp == NULL)
1256                                 error = SET_ERROR(EINVAL);
1257                         if (error == 0)
1258                                 (void) strlcpy(dsname, name, atp - name + 1);
1259                 }
1260                 if (error == 0)
1261                         error = dsl_dataset_hold(dp, dsname, FTAG, &ds);
1262                 if (error == 0) {
1263                         /* passing 0/NULL skips dsl_fs_ss_limit_check */
1264                         error = dsl_dataset_snapshot_check_impl(ds,
1265                             atp + 1, tx, B_FALSE, 0, NULL);
1266                         dsl_dataset_rele(ds, FTAG);
1267                 }
1268 
1269                 if (error != 0) {
1270                         if (ddsa->ddsa_errors != NULL) {
1271                                 fnvlist_add_int32(ddsa->ddsa_errors,
1272                                     name, error);
1273                         }
1274                         rv = error;
1275                 }
1276         }
1277 
1278         return (rv);
1279 }
1280 
1281 void
1282 dsl_dataset_snapshot_sync_impl(dsl_dataset_t *ds, const char *snapname,
1283     dmu_tx_t *tx)
1284 {
1285         static zil_header_t zero_zil;
1286 
1287         dsl_pool_t *dp = ds->ds_dir->dd_pool;
1288         dmu_buf_t *dbuf;
1289         dsl_dataset_phys_t *dsphys;
1290         uint64_t dsobj, crtxg;
1291         objset_t *mos = dp->dp_meta_objset;
1292         objset_t *os;
1293 
1294         ASSERT(RRW_WRITE_HELD(&dp->dp_config_rwlock));
1295 
1296         /*
1297          * If we are on an old pool, the zil must not be active, in which
1298          * case it will be zeroed.  Usually zil_suspend() accomplishes this.
1299          */
1300         ASSERT(spa_version(dmu_tx_pool(tx)->dp_spa) >= SPA_VERSION_FAST_SNAP ||
1301             dmu_objset_from_ds(ds, &os) != 0 ||
1302             bcmp(&os->os_phys->os_zil_header, &zero_zil,
1303             sizeof (zero_zil)) == 0);
1304 
1305         dsl_fs_ss_count_adjust(ds->ds_dir, 1, DD_FIELD_SNAPSHOT_COUNT, tx);
1306 
1307         /*
1308          * The origin's ds_creation_txg has to be < TXG_INITIAL
1309          */
1310         if (strcmp(snapname, ORIGIN_DIR_NAME) == 0)
1311                 crtxg = 1;
1312         else
1313                 crtxg = tx->tx_txg;
1314 
1315         dsobj = dmu_object_alloc(mos, DMU_OT_DSL_DATASET, 0,
1316             DMU_OT_DSL_DATASET, sizeof (dsl_dataset_phys_t), tx);
1317         VERIFY0(dmu_bonus_hold(mos, dsobj, FTAG, &dbuf));
1318         dmu_buf_will_dirty(dbuf, tx);
1319         dsphys = dbuf->db_data;
1320         bzero(dsphys, sizeof (dsl_dataset_phys_t));
1321         dsphys->ds_dir_obj = ds->ds_dir->dd_object;
1322         dsphys->ds_fsid_guid = unique_create();
1323         (void) random_get_pseudo_bytes((void*)&dsphys->ds_guid,
1324             sizeof (dsphys->ds_guid));
1325         dsphys->ds_prev_snap_obj = dsl_dataset_phys(ds)->ds_prev_snap_obj;
1326         dsphys->ds_prev_snap_txg = dsl_dataset_phys(ds)->ds_prev_snap_txg;
1327         dsphys->ds_next_snap_obj = ds->ds_object;
1328         dsphys->ds_num_children = 1;
1329         dsphys->ds_creation_time = gethrestime_sec();
1330         dsphys->ds_creation_txg = crtxg;
1331         dsphys->ds_deadlist_obj = dsl_dataset_phys(ds)->ds_deadlist_obj;
1332         dsphys->ds_referenced_bytes = dsl_dataset_phys(ds)->ds_referenced_bytes;
1333         dsphys->ds_compressed_bytes = dsl_dataset_phys(ds)->ds_compressed_bytes;
1334         dsphys->ds_uncompressed_bytes =
1335             dsl_dataset_phys(ds)->ds_uncompressed_bytes;
1336         dsphys->ds_flags = dsl_dataset_phys(ds)->ds_flags;
1337         dsphys->ds_bp = dsl_dataset_phys(ds)->ds_bp;
1338         dmu_buf_rele(dbuf, FTAG);
1339 
1340         for (spa_feature_t f = 0; f < SPA_FEATURES; f++) {
1341                 if (ds->ds_feature_inuse[f])
1342                         dsl_dataset_activate_feature(dsobj, f, tx);
1343         }
1344 
1345         ASSERT3U(ds->ds_prev != 0, ==,
1346             dsl_dataset_phys(ds)->ds_prev_snap_obj != 0);
1347         if (ds->ds_prev) {
1348                 uint64_t next_clones_obj =
1349                     dsl_dataset_phys(ds->ds_prev)->ds_next_clones_obj;
1350                 ASSERT(dsl_dataset_phys(ds->ds_prev)->ds_next_snap_obj ==
1351                     ds->ds_object ||
1352                     dsl_dataset_phys(ds->ds_prev)->ds_num_children > 1);
1353                 if (dsl_dataset_phys(ds->ds_prev)->ds_next_snap_obj ==
1354                     ds->ds_object) {
1355                         dmu_buf_will_dirty(ds->ds_prev->ds_dbuf, tx);
1356                         ASSERT3U(dsl_dataset_phys(ds)->ds_prev_snap_txg, ==,
1357                             dsl_dataset_phys(ds->ds_prev)->ds_creation_txg);
1358                         dsl_dataset_phys(ds->ds_prev)->ds_next_snap_obj = dsobj;
1359                 } else if (next_clones_obj != 0) {
1360                         dsl_dataset_remove_from_next_clones(ds->ds_prev,
1361                             dsphys->ds_next_snap_obj, tx);
1362                         VERIFY0(zap_add_int(mos,
1363                             next_clones_obj, dsobj, tx));
1364                 }
1365         }
1366 
1367         /*
1368          * If we have a reference-reservation on this dataset, we will
1369          * need to increase the amount of refreservation being charged
1370          * since our unique space is going to zero.
1371          */
1372         if (ds->ds_reserved) {
1373                 int64_t delta;
1374                 ASSERT(DS_UNIQUE_IS_ACCURATE(ds));
1375                 delta = MIN(dsl_dataset_phys(ds)->ds_unique_bytes,
1376                     ds->ds_reserved);
1377                 dsl_dir_diduse_space(ds->ds_dir, DD_USED_REFRSRV,
1378                     delta, 0, 0, tx);
1379         }
1380 
1381         dmu_buf_will_dirty(ds->ds_dbuf, tx);
1382         dsl_dataset_phys(ds)->ds_deadlist_obj =
1383             dsl_deadlist_clone(&ds->ds_deadlist, UINT64_MAX,
1384             dsl_dataset_phys(ds)->ds_prev_snap_obj, tx);
1385         dsl_deadlist_close(&ds->ds_deadlist);
1386         dsl_deadlist_open(&ds->ds_deadlist, mos,
1387             dsl_dataset_phys(ds)->ds_deadlist_obj);
1388         dsl_deadlist_add_key(&ds->ds_deadlist,
1389             dsl_dataset_phys(ds)->ds_prev_snap_txg, tx);
1390 
1391         ASSERT3U(dsl_dataset_phys(ds)->ds_prev_snap_txg, <, tx->tx_txg);
1392         dsl_dataset_phys(ds)->ds_prev_snap_obj = dsobj;
1393         dsl_dataset_phys(ds)->ds_prev_snap_txg = crtxg;
1394         dsl_dataset_phys(ds)->ds_unique_bytes = 0;
1395         if (spa_version(dp->dp_spa) >= SPA_VERSION_UNIQUE_ACCURATE)
1396                 dsl_dataset_phys(ds)->ds_flags |= DS_FLAG_UNIQUE_ACCURATE;
1397 
1398         VERIFY0(zap_add(mos, dsl_dataset_phys(ds)->ds_snapnames_zapobj,
1399             snapname, 8, 1, &dsobj, tx));
1400 
1401         if (ds->ds_prev)
1402                 dsl_dataset_rele(ds->ds_prev, ds);
1403         VERIFY0(dsl_dataset_hold_obj(dp,
1404             dsl_dataset_phys(ds)->ds_prev_snap_obj, ds, &ds->ds_prev));
1405 
1406         dsl_scan_ds_snapshotted(ds, tx);
1407 
1408         dsl_dir_snap_cmtime_update(ds->ds_dir);
1409 
1410         spa_history_log_internal_ds(ds->ds_prev, "snapshot", tx, "");
1411 }
1412 
1413 static void
1414 dsl_dataset_snapshot_sync(void *arg, dmu_tx_t *tx)
1415 {
1416         dsl_dataset_snapshot_arg_t *ddsa = arg;
1417         dsl_pool_t *dp = dmu_tx_pool(tx);
1418         nvpair_t *pair;
1419 
1420         for (pair = nvlist_next_nvpair(ddsa->ddsa_snaps, NULL);
1421             pair != NULL; pair = nvlist_next_nvpair(ddsa->ddsa_snaps, pair)) {
1422                 dsl_dataset_t *ds;
1423                 char *name, *atp;
1424                 char dsname[MAXNAMELEN];
1425 
1426                 name = nvpair_name(pair);
1427                 atp = strchr(name, '@');
1428                 (void) strlcpy(dsname, name, atp - name + 1);
1429                 VERIFY0(dsl_dataset_hold(dp, dsname, FTAG, &ds));
1430 
1431                 dsl_dataset_snapshot_sync_impl(ds, atp + 1, tx);
1432                 if (ddsa->ddsa_props != NULL) {
1433                         dsl_props_set_sync_impl(ds->ds_prev,
1434                             ZPROP_SRC_LOCAL, ddsa->ddsa_props, tx);
1435                 }
1436                 dsl_dataset_rele(ds, FTAG);
1437         }
1438 }
1439 
1440 /*
1441  * The snapshots must all be in the same pool.
1442  * All-or-nothing: if there are any failures, nothing will be modified.
1443  */
1444 int
1445 dsl_dataset_snapshot(nvlist_t *snaps, nvlist_t *props, nvlist_t *errors)
1446 {
1447         dsl_dataset_snapshot_arg_t ddsa;
1448         nvpair_t *pair;
1449         boolean_t needsuspend;
1450         int error;
1451         spa_t *spa;
1452         char *firstname;
1453         nvlist_t *suspended = NULL;
1454 
1455         pair = nvlist_next_nvpair(snaps, NULL);
1456         if (pair == NULL)
1457                 return (0);
1458         firstname = nvpair_name(pair);
1459 
1460         error = spa_open(firstname, &spa, FTAG);
1461         if (error != 0)
1462                 return (error);
1463         needsuspend = (spa_version(spa) < SPA_VERSION_FAST_SNAP);
1464         spa_close(spa, FTAG);
1465 
1466         if (needsuspend) {
1467                 suspended = fnvlist_alloc();
1468                 for (pair = nvlist_next_nvpair(snaps, NULL); pair != NULL;
1469                     pair = nvlist_next_nvpair(snaps, pair)) {
1470                         char fsname[MAXNAMELEN];
1471                         char *snapname = nvpair_name(pair);
1472                         char *atp;
1473                         void *cookie;
1474 
1475                         atp = strchr(snapname, '@');
1476                         if (atp == NULL) {
1477                                 error = SET_ERROR(EINVAL);
1478                                 break;
1479                         }
1480                         (void) strlcpy(fsname, snapname, atp - snapname + 1);
1481 
1482                         error = zil_suspend(fsname, &cookie);
1483                         if (error != 0)
1484                                 break;
1485                         fnvlist_add_uint64(suspended, fsname,
1486                             (uintptr_t)cookie);
1487                 }
1488         }
1489 
1490         ddsa.ddsa_snaps = snaps;
1491         ddsa.ddsa_props = props;
1492         ddsa.ddsa_errors = errors;
1493         ddsa.ddsa_cr = CRED();
1494 
1495         if (error == 0) {
1496                 error = dsl_sync_task(firstname, dsl_dataset_snapshot_check,
1497                     dsl_dataset_snapshot_sync, &ddsa,
1498                     fnvlist_num_pairs(snaps) * 3, ZFS_SPACE_CHECK_NORMAL);
1499         }
1500 
1501         if (suspended != NULL) {
1502                 for (pair = nvlist_next_nvpair(suspended, NULL); pair != NULL;
1503                     pair = nvlist_next_nvpair(suspended, pair)) {
1504                         zil_resume((void *)(uintptr_t)
1505                             fnvpair_value_uint64(pair));
1506                 }
1507                 fnvlist_free(suspended);
1508         }
1509 
1510         return (error);
1511 }
1512 
1513 typedef struct dsl_dataset_snapshot_tmp_arg {
1514         const char *ddsta_fsname;
1515         const char *ddsta_snapname;
1516         minor_t ddsta_cleanup_minor;
1517         const char *ddsta_htag;
1518 } dsl_dataset_snapshot_tmp_arg_t;
1519 
1520 static int
1521 dsl_dataset_snapshot_tmp_check(void *arg, dmu_tx_t *tx)
1522 {
1523         dsl_dataset_snapshot_tmp_arg_t *ddsta = arg;
1524         dsl_pool_t *dp = dmu_tx_pool(tx);
1525         dsl_dataset_t *ds;
1526         int error;
1527 
1528         error = dsl_dataset_hold(dp, ddsta->ddsta_fsname, FTAG, &ds);
1529         if (error != 0)
1530                 return (error);
1531 
1532         /* NULL cred means no limit check for tmp snapshot */
1533         error = dsl_dataset_snapshot_check_impl(ds, ddsta->ddsta_snapname,
1534             tx, B_FALSE, 0, NULL);
1535         if (error != 0) {
1536                 dsl_dataset_rele(ds, FTAG);
1537                 return (error);
1538         }
1539 
1540         if (spa_version(dp->dp_spa) < SPA_VERSION_USERREFS) {
1541                 dsl_dataset_rele(ds, FTAG);
1542                 return (SET_ERROR(ENOTSUP));
1543         }
1544         error = dsl_dataset_user_hold_check_one(NULL, ddsta->ddsta_htag,
1545             B_TRUE, tx);
1546         if (error != 0) {
1547                 dsl_dataset_rele(ds, FTAG);
1548                 return (error);
1549         }
1550 
1551         dsl_dataset_rele(ds, FTAG);
1552         return (0);
1553 }
1554 
1555 static void
1556 dsl_dataset_snapshot_tmp_sync(void *arg, dmu_tx_t *tx)
1557 {
1558         dsl_dataset_snapshot_tmp_arg_t *ddsta = arg;
1559         dsl_pool_t *dp = dmu_tx_pool(tx);
1560         dsl_dataset_t *ds;
1561 
1562         VERIFY0(dsl_dataset_hold(dp, ddsta->ddsta_fsname, FTAG, &ds));
1563 
1564         dsl_dataset_snapshot_sync_impl(ds, ddsta->ddsta_snapname, tx);
1565         dsl_dataset_user_hold_sync_one(ds->ds_prev, ddsta->ddsta_htag,
1566             ddsta->ddsta_cleanup_minor, gethrestime_sec(), tx);
1567         dsl_destroy_snapshot_sync_impl(ds->ds_prev, B_TRUE, tx);
1568 
1569         dsl_dataset_rele(ds, FTAG);
1570 }
1571 
1572 int
1573 dsl_dataset_snapshot_tmp(const char *fsname, const char *snapname,
1574     minor_t cleanup_minor, const char *htag)
1575 {
1576         dsl_dataset_snapshot_tmp_arg_t ddsta;
1577         int error;
1578         spa_t *spa;
1579         boolean_t needsuspend;
1580         void *cookie;
1581 
1582         ddsta.ddsta_fsname = fsname;
1583         ddsta.ddsta_snapname = snapname;
1584         ddsta.ddsta_cleanup_minor = cleanup_minor;
1585         ddsta.ddsta_htag = htag;
1586 
1587         error = spa_open(fsname, &spa, FTAG);
1588         if (error != 0)
1589                 return (error);
1590         needsuspend = (spa_version(spa) < SPA_VERSION_FAST_SNAP);
1591         spa_close(spa, FTAG);
1592 
1593         if (needsuspend) {
1594                 error = zil_suspend(fsname, &cookie);
1595                 if (error != 0)
1596                         return (error);
1597         }
1598 
1599         error = dsl_sync_task(fsname, dsl_dataset_snapshot_tmp_check,
1600             dsl_dataset_snapshot_tmp_sync, &ddsta, 3, ZFS_SPACE_CHECK_RESERVED);
1601 
1602         if (needsuspend)
1603                 zil_resume(cookie);
1604         return (error);
1605 }
1606 
1607 
1608 void
1609 dsl_dataset_sync(dsl_dataset_t *ds, zio_t *zio, dmu_tx_t *tx)
1610 {
1611         ASSERT(dmu_tx_is_syncing(tx));
1612         ASSERT(ds->ds_objset != NULL);
1613         ASSERT(dsl_dataset_phys(ds)->ds_next_snap_obj == 0);
1614 
1615         /*
1616          * in case we had to change ds_fsid_guid when we opened it,
1617          * sync it out now.
1618          */
1619         dmu_buf_will_dirty(ds->ds_dbuf, tx);
1620         dsl_dataset_phys(ds)->ds_fsid_guid = ds->ds_fsid_guid;
1621 
1622         if (ds->ds_resume_bytes[tx->tx_txg & TXG_MASK] != 0) {
1623                 VERIFY0(zap_update(tx->tx_pool->dp_meta_objset,
1624                     ds->ds_object, DS_FIELD_RESUME_OBJECT, 8, 1,
1625                     &ds->ds_resume_object[tx->tx_txg & TXG_MASK], tx));
1626                 VERIFY0(zap_update(tx->tx_pool->dp_meta_objset,
1627                     ds->ds_object, DS_FIELD_RESUME_OFFSET, 8, 1,
1628                     &ds->ds_resume_offset[tx->tx_txg & TXG_MASK], tx));
1629                 VERIFY0(zap_update(tx->tx_pool->dp_meta_objset,
1630                     ds->ds_object, DS_FIELD_RESUME_BYTES, 8, 1,
1631                     &ds->ds_resume_bytes[tx->tx_txg & TXG_MASK], tx));
1632                 ds->ds_resume_object[tx->tx_txg & TXG_MASK] = 0;
1633                 ds->ds_resume_offset[tx->tx_txg & TXG_MASK] = 0;
1634                 ds->ds_resume_bytes[tx->tx_txg & TXG_MASK] = 0;
1635         }
1636 
1637         dmu_objset_sync(ds->ds_objset, zio, tx);
1638 
1639         for (spa_feature_t f = 0; f < SPA_FEATURES; f++) {
1640                 if (ds->ds_feature_activation_needed[f]) {
1641                         if (ds->ds_feature_inuse[f])
1642                                 continue;
1643                         dsl_dataset_activate_feature(ds->ds_object, f, tx);
1644                         ds->ds_feature_inuse[f] = B_TRUE;
1645                 }
1646         }
1647 }
1648 
1649 static void
1650 get_clones_stat(dsl_dataset_t *ds, nvlist_t *nv)
1651 {
1652         uint64_t count = 0;
1653         objset_t *mos = ds->ds_dir->dd_pool->dp_meta_objset;
1654         zap_cursor_t zc;
1655         zap_attribute_t za;
1656         nvlist_t *propval = fnvlist_alloc();
1657         nvlist_t *val = fnvlist_alloc();
1658 
1659         ASSERT(dsl_pool_config_held(ds->ds_dir->dd_pool));
1660 
1661         /*
1662          * There may be missing entries in ds_next_clones_obj
1663          * due to a bug in a previous version of the code.
1664          * Only trust it if it has the right number of entries.
1665          */
1666         if (dsl_dataset_phys(ds)->ds_next_clones_obj != 0) {
1667                 VERIFY0(zap_count(mos, dsl_dataset_phys(ds)->ds_next_clones_obj,
1668                     &count));
1669         }
1670         if (count != dsl_dataset_phys(ds)->ds_num_children - 1)
1671                 goto fail;
1672         for (zap_cursor_init(&zc, mos,
1673             dsl_dataset_phys(ds)->ds_next_clones_obj);
1674             zap_cursor_retrieve(&zc, &za) == 0;
1675             zap_cursor_advance(&zc)) {
1676                 dsl_dataset_t *clone;
1677                 char buf[ZFS_MAXNAMELEN];
1678                 VERIFY0(dsl_dataset_hold_obj(ds->ds_dir->dd_pool,
1679                     za.za_first_integer, FTAG, &clone));
1680                 dsl_dir_name(clone->ds_dir, buf);
1681                 fnvlist_add_boolean(val, buf);
1682                 dsl_dataset_rele(clone, FTAG);
1683         }
1684         zap_cursor_fini(&zc);
1685         fnvlist_add_nvlist(propval, ZPROP_VALUE, val);
1686         fnvlist_add_nvlist(nv, zfs_prop_to_name(ZFS_PROP_CLONES), propval);
1687 fail:
1688         nvlist_free(val);
1689         nvlist_free(propval);
1690 }
1691 
1692 static void
1693 get_receive_resume_stats(dsl_dataset_t *ds, nvlist_t *nv)
1694 {
1695         dsl_pool_t *dp = ds->ds_dir->dd_pool;
1696 
1697         if (dsl_dataset_has_resume_receive_state(ds)) {
1698                 char *str;
1699                 void *packed;
1700                 uint8_t *compressed;
1701                 uint64_t val;
1702                 nvlist_t *token_nv = fnvlist_alloc();
1703                 size_t packed_size, compressed_size;
1704 
1705                 if (zap_lookup(dp->dp_meta_objset, ds->ds_object,
1706                     DS_FIELD_RESUME_FROMGUID, sizeof (val), 1, &val) == 0) {
1707                         fnvlist_add_uint64(token_nv, "fromguid", val);
1708                 }
1709                 if (zap_lookup(dp->dp_meta_objset, ds->ds_object,
1710                     DS_FIELD_RESUME_OBJECT, sizeof (val), 1, &val) == 0) {
1711                         fnvlist_add_uint64(token_nv, "object", val);
1712                 }
1713                 if (zap_lookup(dp->dp_meta_objset, ds->ds_object,
1714                     DS_FIELD_RESUME_OFFSET, sizeof (val), 1, &val) == 0) {
1715                         fnvlist_add_uint64(token_nv, "offset", val);
1716                 }
1717                 if (zap_lookup(dp->dp_meta_objset, ds->ds_object,
1718                     DS_FIELD_RESUME_BYTES, sizeof (val), 1, &val) == 0) {
1719                         fnvlist_add_uint64(token_nv, "bytes", val);
1720                 }
1721                 if (zap_lookup(dp->dp_meta_objset, ds->ds_object,
1722                     DS_FIELD_RESUME_TOGUID, sizeof (val), 1, &val) == 0) {
1723                         fnvlist_add_uint64(token_nv, "toguid", val);
1724                 }
1725                 char buf[256];
1726                 if (zap_lookup(dp->dp_meta_objset, ds->ds_object,
1727                     DS_FIELD_RESUME_TONAME, 1, sizeof (buf), buf) == 0) {
1728                         fnvlist_add_string(token_nv, "toname", buf);
1729                 }
1730                 if (zap_contains(dp->dp_meta_objset, ds->ds_object,
1731                     DS_FIELD_RESUME_EMBEDOK) == 0) {
1732                         fnvlist_add_boolean(token_nv, "embedok");
1733                 }
1734                 packed = fnvlist_pack(token_nv, &packed_size);
1735                 fnvlist_free(token_nv);
1736                 compressed = kmem_alloc(packed_size, KM_SLEEP);
1737 
1738                 compressed_size = gzip_compress(packed, compressed,
1739                     packed_size, packed_size, 6);
1740 
1741                 zio_cksum_t cksum;
1742                 fletcher_4_native(compressed, compressed_size, NULL, &cksum);
1743 
1744                 str = kmem_alloc(compressed_size * 2 + 1, KM_SLEEP);
1745                 for (int i = 0; i < compressed_size; i++) {
1746                         (void) sprintf(str + i * 2, "%02x", compressed[i]);
1747                 }
1748                 str[compressed_size * 2] = '\0';
1749                 char *propval = kmem_asprintf("%u-%llx-%llx-%s",
1750                     ZFS_SEND_RESUME_TOKEN_VERSION,
1751                     (longlong_t)cksum.zc_word[0],
1752                     (longlong_t)packed_size, str);
1753                 dsl_prop_nvlist_add_string(nv,
1754                     ZFS_PROP_RECEIVE_RESUME_TOKEN, propval);
1755                 kmem_free(packed, packed_size);
1756                 kmem_free(str, compressed_size * 2 + 1);
1757                 kmem_free(compressed, packed_size);
1758                 strfree(propval);
1759         }
1760 }
1761 
1762 void
1763 dsl_dataset_stats(dsl_dataset_t *ds, nvlist_t *nv)
1764 {
1765         dsl_pool_t *dp = ds->ds_dir->dd_pool;
1766         uint64_t refd, avail, uobjs, aobjs, ratio;
1767 
1768         ASSERT(dsl_pool_config_held(dp));
1769 
1770         ratio = dsl_dataset_phys(ds)->ds_compressed_bytes == 0 ? 100 :
1771             (dsl_dataset_phys(ds)->ds_uncompressed_bytes * 100 /
1772             dsl_dataset_phys(ds)->ds_compressed_bytes);
1773 
1774         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_REFRATIO, ratio);
1775         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_LOGICALREFERENCED,
1776             dsl_dataset_phys(ds)->ds_uncompressed_bytes);
1777 
1778         if (ds->ds_is_snapshot) {
1779                 dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_COMPRESSRATIO, ratio);
1780                 dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_USED,
1781                     dsl_dataset_phys(ds)->ds_unique_bytes);
1782                 get_clones_stat(ds, nv);
1783         } else {
1784                 if (ds->ds_prev != NULL && ds->ds_prev != dp->dp_origin_snap) {
1785                         char buf[MAXNAMELEN];
1786                         dsl_dataset_name(ds->ds_prev, buf);
1787                         dsl_prop_nvlist_add_string(nv, ZFS_PROP_PREV_SNAP, buf);
1788                 }
1789 
1790                 dsl_dir_stats(ds->ds_dir, nv);
1791         }
1792 
1793         dsl_dataset_space(ds, &refd, &avail, &uobjs, &aobjs);
1794         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_AVAILABLE, avail);
1795         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_REFERENCED, refd);
1796 
1797         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_CREATION,
1798             dsl_dataset_phys(ds)->ds_creation_time);
1799         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_CREATETXG,
1800             dsl_dataset_phys(ds)->ds_creation_txg);
1801         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_REFQUOTA,
1802             ds->ds_quota);
1803         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_REFRESERVATION,
1804             ds->ds_reserved);
1805         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_GUID,
1806             dsl_dataset_phys(ds)->ds_guid);
1807         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_UNIQUE,
1808             dsl_dataset_phys(ds)->ds_unique_bytes);
1809         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_OBJSETID,
1810             ds->ds_object);
1811         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_USERREFS,
1812             ds->ds_userrefs);
1813         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_DEFER_DESTROY,
1814             DS_IS_DEFER_DESTROY(ds) ? 1 : 0);
1815 
1816         if (dsl_dataset_phys(ds)->ds_prev_snap_obj != 0) {
1817                 uint64_t written, comp, uncomp;
1818                 dsl_pool_t *dp = ds->ds_dir->dd_pool;
1819                 dsl_dataset_t *prev;
1820 
1821                 int err = dsl_dataset_hold_obj(dp,
1822                     dsl_dataset_phys(ds)->ds_prev_snap_obj, FTAG, &prev);
1823                 if (err == 0) {
1824                         err = dsl_dataset_space_written(prev, ds, &written,
1825                             &comp, &uncomp);
1826                         dsl_dataset_rele(prev, FTAG);
1827                         if (err == 0) {
1828                                 dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_WRITTEN,
1829                                     written);
1830                         }
1831                 }
1832         }
1833 
1834         if (!dsl_dataset_is_snapshot(ds)) {
1835                 /*
1836                  * A failed "newfs" (e.g. full) resumable receive leaves
1837                  * the stats set on this dataset.  Check here for the prop.
1838                  */
1839                 get_receive_resume_stats(ds, nv);
1840 
1841                 /*
1842                  * A failed incremental resumable receive leaves the
1843                  * stats set on our child named "%recv".  Check the child
1844                  * for the prop.
1845                  */
1846                 char recvname[ZFS_MAXNAMELEN];
1847                 dsl_dataset_t *recv_ds;
1848                 dsl_dataset_name(ds, recvname);
1849                 (void) strcat(recvname, "/");
1850                 (void) strcat(recvname, recv_clone_name);
1851                 if (dsl_dataset_hold(dp, recvname, FTAG, &recv_ds) == 0) {
1852                         get_receive_resume_stats(recv_ds, nv);
1853                         dsl_dataset_rele(recv_ds, FTAG);
1854                 }
1855         }
1856 }
1857 
1858 void
1859 dsl_dataset_fast_stat(dsl_dataset_t *ds, dmu_objset_stats_t *stat)
1860 {
1861         dsl_pool_t *dp = ds->ds_dir->dd_pool;
1862         ASSERT(dsl_pool_config_held(dp));
1863 
1864         stat->dds_creation_txg = dsl_dataset_phys(ds)->ds_creation_txg;
1865         stat->dds_inconsistent =
1866             dsl_dataset_phys(ds)->ds_flags & DS_FLAG_INCONSISTENT;
1867         stat->dds_guid = dsl_dataset_phys(ds)->ds_guid;
1868         stat->dds_origin[0] = '\0';
1869         if (ds->ds_is_snapshot) {
1870                 stat->dds_is_snapshot = B_TRUE;
1871                 stat->dds_num_clones =
1872                     dsl_dataset_phys(ds)->ds_num_children - 1;
1873         } else {
1874                 stat->dds_is_snapshot = B_FALSE;
1875                 stat->dds_num_clones = 0;
1876 
1877                 if (dsl_dir_is_clone(ds->ds_dir)) {
1878                         dsl_dataset_t *ods;
1879 
1880                         VERIFY0(dsl_dataset_hold_obj(dp,
1881                             dsl_dir_phys(ds->ds_dir)->dd_origin_obj,
1882                             FTAG, &ods));
1883                         dsl_dataset_name(ods, stat->dds_origin);
1884                         dsl_dataset_rele(ods, FTAG);
1885                 }
1886         }
1887 }
1888 
1889 uint64_t
1890 dsl_dataset_fsid_guid(dsl_dataset_t *ds)
1891 {
1892         return (ds->ds_fsid_guid);
1893 }
1894 
1895 void
1896 dsl_dataset_space(dsl_dataset_t *ds,
1897     uint64_t *refdbytesp, uint64_t *availbytesp,
1898     uint64_t *usedobjsp, uint64_t *availobjsp)
1899 {
1900         *refdbytesp = dsl_dataset_phys(ds)->ds_referenced_bytes;
1901         *availbytesp = dsl_dir_space_available(ds->ds_dir, NULL, 0, TRUE);
1902         if (ds->ds_reserved > dsl_dataset_phys(ds)->ds_unique_bytes)
1903                 *availbytesp +=
1904                     ds->ds_reserved - dsl_dataset_phys(ds)->ds_unique_bytes;
1905         if (ds->ds_quota != 0) {
1906                 /*
1907                  * Adjust available bytes according to refquota
1908                  */
1909                 if (*refdbytesp < ds->ds_quota)
1910                         *availbytesp = MIN(*availbytesp,
1911                             ds->ds_quota - *refdbytesp);
1912                 else
1913                         *availbytesp = 0;
1914         }
1915         *usedobjsp = BP_GET_FILL(&dsl_dataset_phys(ds)->ds_bp);
1916         *availobjsp = DN_MAX_OBJECT - *usedobjsp;
1917 }
1918 
1919 boolean_t
1920 dsl_dataset_modified_since_snap(dsl_dataset_t *ds, dsl_dataset_t *snap)
1921 {
1922         dsl_pool_t *dp = ds->ds_dir->dd_pool;
1923 
1924         ASSERT(dsl_pool_config_held(dp));
1925         if (snap == NULL)
1926                 return (B_FALSE);
1927         if (dsl_dataset_phys(ds)->ds_bp.blk_birth >
1928             dsl_dataset_phys(snap)->ds_creation_txg) {
1929                 objset_t *os, *os_snap;
1930                 /*
1931                  * It may be that only the ZIL differs, because it was
1932                  * reset in the head.  Don't count that as being
1933                  * modified.
1934                  */
1935                 if (dmu_objset_from_ds(ds, &os) != 0)
1936                         return (B_TRUE);
1937                 if (dmu_objset_from_ds(snap, &os_snap) != 0)
1938                         return (B_TRUE);
1939                 return (bcmp(&os->os_phys->os_meta_dnode,
1940                     &os_snap->os_phys->os_meta_dnode,
1941                     sizeof (os->os_phys->os_meta_dnode)) != 0);
1942         }
1943         return (B_FALSE);
1944 }
1945 
1946 typedef struct dsl_dataset_rename_snapshot_arg {
1947         const char *ddrsa_fsname;
1948         const char *ddrsa_oldsnapname;
1949         const char *ddrsa_newsnapname;
1950         boolean_t ddrsa_recursive;
1951         dmu_tx_t *ddrsa_tx;
1952 } dsl_dataset_rename_snapshot_arg_t;
1953 
1954 /* ARGSUSED */
1955 static int
1956 dsl_dataset_rename_snapshot_check_impl(dsl_pool_t *dp,
1957     dsl_dataset_t *hds, void *arg)
1958 {
1959         dsl_dataset_rename_snapshot_arg_t *ddrsa = arg;
1960         int error;
1961         uint64_t val;
1962 
1963         error = dsl_dataset_snap_lookup(hds, ddrsa->ddrsa_oldsnapname, &val);
1964         if (error != 0) {
1965                 /* ignore nonexistent snapshots */
1966                 return (error == ENOENT ? 0 : error);
1967         }
1968 
1969         /* new name should not exist */
1970         error = dsl_dataset_snap_lookup(hds, ddrsa->ddrsa_newsnapname, &val);
1971         if (error == 0)
1972                 error = SET_ERROR(EEXIST);
1973         else if (error == ENOENT)
1974                 error = 0;
1975 
1976         /* dataset name + 1 for the "@" + the new snapshot name must fit */
1977         if (dsl_dir_namelen(hds->ds_dir) + 1 +
1978             strlen(ddrsa->ddrsa_newsnapname) >= MAXNAMELEN)
1979                 error = SET_ERROR(ENAMETOOLONG);
1980 
1981         return (error);
1982 }
1983 
1984 static int
1985 dsl_dataset_rename_snapshot_check(void *arg, dmu_tx_t *tx)
1986 {
1987         dsl_dataset_rename_snapshot_arg_t *ddrsa = arg;
1988         dsl_pool_t *dp = dmu_tx_pool(tx);
1989         dsl_dataset_t *hds;
1990         int error;
1991 
1992         error = dsl_dataset_hold(dp, ddrsa->ddrsa_fsname, FTAG, &hds);
1993         if (error != 0)
1994                 return (error);
1995 
1996         if (ddrsa->ddrsa_recursive) {
1997                 error = dmu_objset_find_dp(dp, hds->ds_dir->dd_object,
1998                     dsl_dataset_rename_snapshot_check_impl, ddrsa,
1999                     DS_FIND_CHILDREN);
2000         } else {
2001                 error = dsl_dataset_rename_snapshot_check_impl(dp, hds, ddrsa);
2002         }
2003         dsl_dataset_rele(hds, FTAG);
2004         return (error);
2005 }
2006 
2007 static int
2008 dsl_dataset_rename_snapshot_sync_impl(dsl_pool_t *dp,
2009     dsl_dataset_t *hds, void *arg)
2010 {
2011         dsl_dataset_rename_snapshot_arg_t *ddrsa = arg;
2012         dsl_dataset_t *ds;
2013         uint64_t val;
2014         dmu_tx_t *tx = ddrsa->ddrsa_tx;
2015         int error;
2016 
2017         error = dsl_dataset_snap_lookup(hds, ddrsa->ddrsa_oldsnapname, &val);
2018         ASSERT(error == 0 || error == ENOENT);
2019         if (error == ENOENT) {
2020                 /* ignore nonexistent snapshots */
2021                 return (0);
2022         }
2023 
2024         VERIFY0(dsl_dataset_hold_obj(dp, val, FTAG, &ds));
2025 
2026         /* log before we change the name */
2027         spa_history_log_internal_ds(ds, "rename", tx,
2028             "-> @%s", ddrsa->ddrsa_newsnapname);
2029 
2030         VERIFY0(dsl_dataset_snap_remove(hds, ddrsa->ddrsa_oldsnapname, tx,
2031             B_FALSE));
2032         mutex_enter(&ds->ds_lock);
2033         (void) strcpy(ds->ds_snapname, ddrsa->ddrsa_newsnapname);
2034         mutex_exit(&ds->ds_lock);
2035         VERIFY0(zap_add(dp->dp_meta_objset,
2036             dsl_dataset_phys(hds)->ds_snapnames_zapobj,
2037             ds->ds_snapname, 8, 1, &ds->ds_object, tx));
2038 
2039         dsl_dataset_rele(ds, FTAG);
2040         return (0);
2041 }
2042 
2043 static void
2044 dsl_dataset_rename_snapshot_sync(void *arg, dmu_tx_t *tx)
2045 {
2046         dsl_dataset_rename_snapshot_arg_t *ddrsa = arg;
2047         dsl_pool_t *dp = dmu_tx_pool(tx);
2048         dsl_dataset_t *hds;
2049 
2050         VERIFY0(dsl_dataset_hold(dp, ddrsa->ddrsa_fsname, FTAG, &hds));
2051         ddrsa->ddrsa_tx = tx;
2052         if (ddrsa->ddrsa_recursive) {
2053                 VERIFY0(dmu_objset_find_dp(dp, hds->ds_dir->dd_object,
2054                     dsl_dataset_rename_snapshot_sync_impl, ddrsa,
2055                     DS_FIND_CHILDREN));
2056         } else {
2057                 VERIFY0(dsl_dataset_rename_snapshot_sync_impl(dp, hds, ddrsa));
2058         }
2059         dsl_dataset_rele(hds, FTAG);
2060 }
2061 
2062 int
2063 dsl_dataset_rename_snapshot(const char *fsname,
2064     const char *oldsnapname, const char *newsnapname, boolean_t recursive)
2065 {
2066         dsl_dataset_rename_snapshot_arg_t ddrsa;
2067 
2068         ddrsa.ddrsa_fsname = fsname;
2069         ddrsa.ddrsa_oldsnapname = oldsnapname;
2070         ddrsa.ddrsa_newsnapname = newsnapname;
2071         ddrsa.ddrsa_recursive = recursive;
2072 
2073         return (dsl_sync_task(fsname, dsl_dataset_rename_snapshot_check,
2074             dsl_dataset_rename_snapshot_sync, &ddrsa,
2075             1, ZFS_SPACE_CHECK_RESERVED));
2076 }
2077 
2078 /*
2079  * If we're doing an ownership handoff, we need to make sure that there is
2080  * only one long hold on the dataset.  We're not allowed to change anything here
2081  * so we don't permanently release the long hold or regular hold here.  We want
2082  * to do this only when syncing to avoid the dataset unexpectedly going away
2083  * when we release the long hold.
2084  */
2085 static int
2086 dsl_dataset_handoff_check(dsl_dataset_t *ds, void *owner, dmu_tx_t *tx)
2087 {
2088         boolean_t held;
2089 
2090         if (!dmu_tx_is_syncing(tx))
2091                 return (0);
2092 
2093         if (owner != NULL) {
2094                 VERIFY3P(ds->ds_owner, ==, owner);
2095                 dsl_dataset_long_rele(ds, owner);
2096         }
2097 
2098         held = dsl_dataset_long_held(ds);
2099 
2100         if (owner != NULL)
2101                 dsl_dataset_long_hold(ds, owner);
2102 
2103         if (held)
2104                 return (SET_ERROR(EBUSY));
2105 
2106         return (0);
2107 }
2108 
2109 typedef struct dsl_dataset_rollback_arg {
2110         const char *ddra_fsname;
2111         void *ddra_owner;
2112         nvlist_t *ddra_result;
2113 } dsl_dataset_rollback_arg_t;
2114 
2115 static int
2116 dsl_dataset_rollback_check(void *arg, dmu_tx_t *tx)
2117 {
2118         dsl_dataset_rollback_arg_t *ddra = arg;
2119         dsl_pool_t *dp = dmu_tx_pool(tx);
2120         dsl_dataset_t *ds;
2121         int64_t unused_refres_delta;
2122         int error;
2123 
2124         error = dsl_dataset_hold(dp, ddra->ddra_fsname, FTAG, &ds);
2125         if (error != 0)
2126                 return (error);
2127 
2128         /* must not be a snapshot */
2129         if (ds->ds_is_snapshot) {
2130                 dsl_dataset_rele(ds, FTAG);
2131                 return (SET_ERROR(EINVAL));
2132         }
2133 
2134         /* must have a most recent snapshot */
2135         if (dsl_dataset_phys(ds)->ds_prev_snap_txg < TXG_INITIAL) {
2136                 dsl_dataset_rele(ds, FTAG);
2137                 return (SET_ERROR(EINVAL));
2138         }
2139 
2140         /* must not have any bookmarks after the most recent snapshot */
2141         nvlist_t *proprequest = fnvlist_alloc();
2142         fnvlist_add_boolean(proprequest, zfs_prop_to_name(ZFS_PROP_CREATETXG));
2143         nvlist_t *bookmarks = fnvlist_alloc();
2144         error = dsl_get_bookmarks_impl(ds, proprequest, bookmarks);
2145         fnvlist_free(proprequest);
2146         if (error != 0)
2147                 return (error);
2148         for (nvpair_t *pair = nvlist_next_nvpair(bookmarks, NULL);
2149             pair != NULL; pair = nvlist_next_nvpair(bookmarks, pair)) {
2150                 nvlist_t *valuenv =
2151                     fnvlist_lookup_nvlist(fnvpair_value_nvlist(pair),
2152                     zfs_prop_to_name(ZFS_PROP_CREATETXG));
2153                 uint64_t createtxg = fnvlist_lookup_uint64(valuenv, "value");
2154                 if (createtxg > dsl_dataset_phys(ds)->ds_prev_snap_txg) {
2155                         fnvlist_free(bookmarks);
2156                         dsl_dataset_rele(ds, FTAG);
2157                         return (SET_ERROR(EEXIST));
2158                 }
2159         }
2160         fnvlist_free(bookmarks);
2161 
2162         error = dsl_dataset_handoff_check(ds, ddra->ddra_owner, tx);
2163         if (error != 0) {
2164                 dsl_dataset_rele(ds, FTAG);
2165                 return (error);
2166         }
2167 
2168         /*
2169          * Check if the snap we are rolling back to uses more than
2170          * the refquota.
2171          */
2172         if (ds->ds_quota != 0 &&
2173             dsl_dataset_phys(ds->ds_prev)->ds_referenced_bytes > ds->ds_quota) {
2174                 dsl_dataset_rele(ds, FTAG);
2175                 return (SET_ERROR(EDQUOT));
2176         }
2177 
2178         /*
2179          * When we do the clone swap, we will temporarily use more space
2180          * due to the refreservation (the head will no longer have any
2181          * unique space, so the entire amount of the refreservation will need
2182          * to be free).  We will immediately destroy the clone, freeing
2183          * this space, but the freeing happens over many txg's.
2184          */
2185         unused_refres_delta = (int64_t)MIN(ds->ds_reserved,
2186             dsl_dataset_phys(ds)->ds_unique_bytes);
2187 
2188         if (unused_refres_delta > 0 &&
2189             unused_refres_delta >
2190             dsl_dir_space_available(ds->ds_dir, NULL, 0, TRUE)) {
2191                 dsl_dataset_rele(ds, FTAG);
2192                 return (SET_ERROR(ENOSPC));
2193         }
2194 
2195         dsl_dataset_rele(ds, FTAG);
2196         return (0);
2197 }
2198 
2199 static void
2200 dsl_dataset_rollback_sync(void *arg, dmu_tx_t *tx)
2201 {
2202         dsl_dataset_rollback_arg_t *ddra = arg;
2203         dsl_pool_t *dp = dmu_tx_pool(tx);
2204         dsl_dataset_t *ds, *clone;
2205         uint64_t cloneobj;
2206         char namebuf[ZFS_MAXNAMELEN];
2207 
2208         VERIFY0(dsl_dataset_hold(dp, ddra->ddra_fsname, FTAG, &ds));
2209 
2210         dsl_dataset_name(ds->ds_prev, namebuf);
2211         fnvlist_add_string(ddra->ddra_result, "target", namebuf);
2212 
2213         cloneobj = dsl_dataset_create_sync(ds->ds_dir, "%rollback",
2214             ds->ds_prev, DS_CREATE_FLAG_NODIRTY, kcred, tx);
2215 
2216         VERIFY0(dsl_dataset_hold_obj(dp, cloneobj, FTAG, &clone));
2217 
2218         dsl_dataset_clone_swap_sync_impl(clone, ds, tx);
2219         dsl_dataset_zero_zil(ds, tx);
2220 
2221         dsl_destroy_head_sync_impl(clone, tx);
2222 
2223         dsl_dataset_rele(clone, FTAG);
2224         dsl_dataset_rele(ds, FTAG);
2225 }
2226 
2227 /*
2228  * Rolls back the given filesystem or volume to the most recent snapshot.
2229  * The name of the most recent snapshot will be returned under key "target"
2230  * in the result nvlist.
2231  *
2232  * If owner != NULL:
2233  * - The existing dataset MUST be owned by the specified owner at entry
2234  * - Upon return, dataset will still be held by the same owner, whether we
2235  *   succeed or not.
2236  *
2237  * This mode is required any time the existing filesystem is mounted.  See
2238  * notes above zfs_suspend_fs() for further details.
2239  */
2240 int
2241 dsl_dataset_rollback(const char *fsname, void *owner, nvlist_t *result)
2242 {
2243         dsl_dataset_rollback_arg_t ddra;
2244 
2245         ddra.ddra_fsname = fsname;
2246         ddra.ddra_owner = owner;
2247         ddra.ddra_result = result;
2248 
2249         return (dsl_sync_task(fsname, dsl_dataset_rollback_check,
2250             dsl_dataset_rollback_sync, &ddra,
2251             1, ZFS_SPACE_CHECK_RESERVED));
2252 }
2253 
2254 struct promotenode {
2255         list_node_t link;
2256         dsl_dataset_t *ds;
2257 };
2258 
2259 typedef struct dsl_dataset_promote_arg {
2260         const char *ddpa_clonename;
2261         dsl_dataset_t *ddpa_clone;
2262         list_t shared_snaps, origin_snaps, clone_snaps;
2263         dsl_dataset_t *origin_origin; /* origin of the origin */
2264         uint64_t used, comp, uncomp, unique, cloneusedsnap, originusedsnap;
2265         char *err_ds;
2266         cred_t *cr;
2267 } dsl_dataset_promote_arg_t;
2268 
2269 static int snaplist_space(list_t *l, uint64_t mintxg, uint64_t *spacep);
2270 static int promote_hold(dsl_dataset_promote_arg_t *ddpa, dsl_pool_t *dp,
2271     void *tag);
2272 static void promote_rele(dsl_dataset_promote_arg_t *ddpa, void *tag);
2273 
2274 static int
2275 dsl_dataset_promote_check(void *arg, dmu_tx_t *tx)
2276 {
2277         dsl_dataset_promote_arg_t *ddpa = arg;
2278         dsl_pool_t *dp = dmu_tx_pool(tx);
2279         dsl_dataset_t *hds;
2280         struct promotenode *snap;
2281         dsl_dataset_t *origin_ds;
2282         int err;
2283         uint64_t unused;
2284         uint64_t ss_mv_cnt;
2285         size_t max_snap_len;
2286 
2287         err = promote_hold(ddpa, dp, FTAG);
2288         if (err != 0)
2289                 return (err);
2290 
2291         hds = ddpa->ddpa_clone;
2292         max_snap_len = MAXNAMELEN - strlen(ddpa->ddpa_clonename) - 1;
2293 
2294         if (dsl_dataset_phys(hds)->ds_flags & DS_FLAG_NOPROMOTE) {
2295                 promote_rele(ddpa, FTAG);
2296                 return (SET_ERROR(EXDEV));
2297         }
2298 
2299         /*
2300          * Compute and check the amount of space to transfer.  Since this is
2301          * so expensive, don't do the preliminary check.
2302          */
2303         if (!dmu_tx_is_syncing(tx)) {
2304                 promote_rele(ddpa, FTAG);
2305                 return (0);
2306         }
2307 
2308         snap = list_head(&ddpa->shared_snaps);
2309         origin_ds = snap->ds;
2310 
2311         /* compute origin's new unique space */
2312         snap = list_tail(&ddpa->clone_snaps);
2313         ASSERT3U(dsl_dataset_phys(snap->ds)->ds_prev_snap_obj, ==,
2314             origin_ds->ds_object);
2315         dsl_deadlist_space_range(&snap->ds->ds_deadlist,
2316             dsl_dataset_phys(origin_ds)->ds_prev_snap_txg, UINT64_MAX,
2317             &ddpa->unique, &unused, &unused);
2318 
2319         /*
2320          * Walk the snapshots that we are moving
2321          *
2322          * Compute space to transfer.  Consider the incremental changes
2323          * to used by each snapshot:
2324          * (my used) = (prev's used) + (blocks born) - (blocks killed)
2325          * So each snapshot gave birth to:
2326          * (blocks born) = (my used) - (prev's used) + (blocks killed)
2327          * So a sequence would look like:
2328          * (uN - u(N-1) + kN) + ... + (u1 - u0 + k1) + (u0 - 0 + k0)
2329          * Which simplifies to:
2330          * uN + kN + kN-1 + ... + k1 + k0
2331          * Note however, if we stop before we reach the ORIGIN we get:
2332          * uN + kN + kN-1 + ... + kM - uM-1
2333          */
2334         ss_mv_cnt = 0;
2335         ddpa->used = dsl_dataset_phys(origin_ds)->ds_referenced_bytes;
2336         ddpa->comp = dsl_dataset_phys(origin_ds)->ds_compressed_bytes;
2337         ddpa->uncomp = dsl_dataset_phys(origin_ds)->ds_uncompressed_bytes;
2338         for (snap = list_head(&ddpa->shared_snaps); snap;
2339             snap = list_next(&ddpa->shared_snaps, snap)) {
2340                 uint64_t val, dlused, dlcomp, dluncomp;
2341                 dsl_dataset_t *ds = snap->ds;
2342 
2343                 ss_mv_cnt++;
2344 
2345                 /*
2346                  * If there are long holds, we won't be able to evict
2347                  * the objset.
2348                  */
2349                 if (dsl_dataset_long_held(ds)) {
2350                         err = SET_ERROR(EBUSY);
2351                         goto out;
2352                 }
2353 
2354                 /* Check that the snapshot name does not conflict */
2355                 VERIFY0(dsl_dataset_get_snapname(ds));
2356                 if (strlen(ds->ds_snapname) >= max_snap_len) {
2357                         err = SET_ERROR(ENAMETOOLONG);
2358                         goto out;
2359                 }
2360                 err = dsl_dataset_snap_lookup(hds, ds->ds_snapname, &val);
2361                 if (err == 0) {
2362                         (void) strcpy(ddpa->err_ds, snap->ds->ds_snapname);
2363                         err = SET_ERROR(EEXIST);
2364                         goto out;
2365                 }
2366                 if (err != ENOENT)
2367                         goto out;
2368 
2369                 /* The very first snapshot does not have a deadlist */
2370                 if (dsl_dataset_phys(ds)->ds_prev_snap_obj == 0)
2371                         continue;
2372 
2373                 dsl_deadlist_space(&ds->ds_deadlist,
2374                     &dlused, &dlcomp, &dluncomp);
2375                 ddpa->used += dlused;
2376                 ddpa->comp += dlcomp;
2377                 ddpa->uncomp += dluncomp;
2378         }
2379 
2380         /*
2381          * If we are a clone of a clone then we never reached ORIGIN,
2382          * so we need to subtract out the clone origin's used space.
2383          */
2384         if (ddpa->origin_origin) {
2385                 ddpa->used -=
2386                     dsl_dataset_phys(ddpa->origin_origin)->ds_referenced_bytes;
2387                 ddpa->comp -=
2388                     dsl_dataset_phys(ddpa->origin_origin)->ds_compressed_bytes;
2389                 ddpa->uncomp -=
2390                     dsl_dataset_phys(ddpa->origin_origin)->
2391                     ds_uncompressed_bytes;
2392         }
2393 
2394         /* Check that there is enough space and limit headroom here */
2395         err = dsl_dir_transfer_possible(origin_ds->ds_dir, hds->ds_dir,
2396             0, ss_mv_cnt, ddpa->used, ddpa->cr);
2397         if (err != 0)
2398                 goto out;
2399 
2400         /*
2401          * Compute the amounts of space that will be used by snapshots
2402          * after the promotion (for both origin and clone).  For each,
2403          * it is the amount of space that will be on all of their
2404          * deadlists (that was not born before their new origin).
2405          */
2406         if (dsl_dir_phys(hds->ds_dir)->dd_flags & DD_FLAG_USED_BREAKDOWN) {
2407                 uint64_t space;
2408 
2409                 /*
2410                  * Note, typically this will not be a clone of a clone,
2411                  * so dd_origin_txg will be < TXG_INITIAL, so
2412                  * these snaplist_space() -> dsl_deadlist_space_range()
2413                  * calls will be fast because they do not have to
2414                  * iterate over all bps.
2415                  */
2416                 snap = list_head(&ddpa->origin_snaps);
2417                 err = snaplist_space(&ddpa->shared_snaps,
2418                     snap->ds->ds_dir->dd_origin_txg, &ddpa->cloneusedsnap);
2419                 if (err != 0)
2420                         goto out;
2421 
2422                 err = snaplist_space(&ddpa->clone_snaps,
2423                     snap->ds->ds_dir->dd_origin_txg, &space);
2424                 if (err != 0)
2425                         goto out;
2426                 ddpa->cloneusedsnap += space;
2427         }
2428         if (dsl_dir_phys(origin_ds->ds_dir)->dd_flags &
2429             DD_FLAG_USED_BREAKDOWN) {
2430                 err = snaplist_space(&ddpa->origin_snaps,
2431                     dsl_dataset_phys(origin_ds)->ds_creation_txg,
2432                     &ddpa->originusedsnap);
2433                 if (err != 0)
2434                         goto out;
2435         }
2436 
2437 out:
2438         promote_rele(ddpa, FTAG);
2439         return (err);
2440 }
2441 
2442 static void
2443 dsl_dataset_promote_sync(void *arg, dmu_tx_t *tx)
2444 {
2445         dsl_dataset_promote_arg_t *ddpa = arg;
2446         dsl_pool_t *dp = dmu_tx_pool(tx);
2447         dsl_dataset_t *hds;
2448         struct promotenode *snap;
2449         dsl_dataset_t *origin_ds;
2450         dsl_dataset_t *origin_head;
2451         dsl_dir_t *dd;
2452         dsl_dir_t *odd = NULL;
2453         uint64_t oldnext_obj;
2454         int64_t delta;
2455 
2456         VERIFY0(promote_hold(ddpa, dp, FTAG));
2457         hds = ddpa->ddpa_clone;
2458 
2459         ASSERT0(dsl_dataset_phys(hds)->ds_flags & DS_FLAG_NOPROMOTE);
2460 
2461         snap = list_head(&ddpa->shared_snaps);
2462         origin_ds = snap->ds;
2463         dd = hds->ds_dir;
2464 
2465         snap = list_head(&ddpa->origin_snaps);
2466         origin_head = snap->ds;
2467 
2468         /*
2469          * We need to explicitly open odd, since origin_ds's dd will be
2470          * changing.
2471          */
2472         VERIFY0(dsl_dir_hold_obj(dp, origin_ds->ds_dir->dd_object,
2473             NULL, FTAG, &odd));
2474 
2475         /* change origin's next snap */
2476         dmu_buf_will_dirty(origin_ds->ds_dbuf, tx);
2477         oldnext_obj = dsl_dataset_phys(origin_ds)->ds_next_snap_obj;
2478         snap = list_tail(&ddpa->clone_snaps);
2479         ASSERT3U(dsl_dataset_phys(snap->ds)->ds_prev_snap_obj, ==,
2480             origin_ds->ds_object);
2481         dsl_dataset_phys(origin_ds)->ds_next_snap_obj = snap->ds->ds_object;
2482 
2483         /* change the origin's next clone */
2484         if (dsl_dataset_phys(origin_ds)->ds_next_clones_obj) {
2485                 dsl_dataset_remove_from_next_clones(origin_ds,
2486                     snap->ds->ds_object, tx);
2487                 VERIFY0(zap_add_int(dp->dp_meta_objset,
2488                     dsl_dataset_phys(origin_ds)->ds_next_clones_obj,
2489                     oldnext_obj, tx));
2490         }
2491 
2492         /* change origin */
2493         dmu_buf_will_dirty(dd->dd_dbuf, tx);
2494         ASSERT3U(dsl_dir_phys(dd)->dd_origin_obj, ==, origin_ds->ds_object);
2495         dsl_dir_phys(dd)->dd_origin_obj = dsl_dir_phys(odd)->dd_origin_obj;
2496         dd->dd_origin_txg = origin_head->ds_dir->dd_origin_txg;
2497         dmu_buf_will_dirty(odd->dd_dbuf, tx);
2498         dsl_dir_phys(odd)->dd_origin_obj = origin_ds->ds_object;
2499         origin_head->ds_dir->dd_origin_txg =
2500             dsl_dataset_phys(origin_ds)->ds_creation_txg;
2501 
2502         /* change dd_clone entries */
2503         if (spa_version(dp->dp_spa) >= SPA_VERSION_DIR_CLONES) {
2504                 VERIFY0(zap_remove_int(dp->dp_meta_objset,
2505                     dsl_dir_phys(odd)->dd_clones, hds->ds_object, tx));
2506                 VERIFY0(zap_add_int(dp->dp_meta_objset,
2507                     dsl_dir_phys(ddpa->origin_origin->ds_dir)->dd_clones,
2508                     hds->ds_object, tx));
2509 
2510                 VERIFY0(zap_remove_int(dp->dp_meta_objset,
2511                     dsl_dir_phys(ddpa->origin_origin->ds_dir)->dd_clones,
2512                     origin_head->ds_object, tx));
2513                 if (dsl_dir_phys(dd)->dd_clones == 0) {
2514                         dsl_dir_phys(dd)->dd_clones =
2515                             zap_create(dp->dp_meta_objset, DMU_OT_DSL_CLONES,
2516                             DMU_OT_NONE, 0, tx);
2517                 }
2518                 VERIFY0(zap_add_int(dp->dp_meta_objset,
2519                     dsl_dir_phys(dd)->dd_clones, origin_head->ds_object, tx));
2520         }
2521 
2522         /* move snapshots to this dir */
2523         for (snap = list_head(&ddpa->shared_snaps); snap;
2524             snap = list_next(&ddpa->shared_snaps, snap)) {
2525                 dsl_dataset_t *ds = snap->ds;
2526 
2527                 /*
2528                  * Property callbacks are registered to a particular
2529                  * dsl_dir.  Since ours is changing, evict the objset
2530                  * so that they will be unregistered from the old dsl_dir.
2531                  */
2532                 if (ds->ds_objset) {
2533                         dmu_objset_evict(ds->ds_objset);
2534                         ds->ds_objset = NULL;
2535                 }
2536 
2537                 /* move snap name entry */
2538                 VERIFY0(dsl_dataset_get_snapname(ds));
2539                 VERIFY0(dsl_dataset_snap_remove(origin_head,
2540                     ds->ds_snapname, tx, B_TRUE));
2541                 VERIFY0(zap_add(dp->dp_meta_objset,
2542                     dsl_dataset_phys(hds)->ds_snapnames_zapobj, ds->ds_snapname,
2543                     8, 1, &ds->ds_object, tx));
2544                 dsl_fs_ss_count_adjust(hds->ds_dir, 1,
2545                     DD_FIELD_SNAPSHOT_COUNT, tx);
2546 
2547                 /* change containing dsl_dir */
2548                 dmu_buf_will_dirty(ds->ds_dbuf, tx);
2549                 ASSERT3U(dsl_dataset_phys(ds)->ds_dir_obj, ==, odd->dd_object);
2550                 dsl_dataset_phys(ds)->ds_dir_obj = dd->dd_object;
2551                 ASSERT3P(ds->ds_dir, ==, odd);
2552                 dsl_dir_rele(ds->ds_dir, ds);
2553                 VERIFY0(dsl_dir_hold_obj(dp, dd->dd_object,
2554                     NULL, ds, &ds->ds_dir));
2555 
2556                 /* move any clone references */
2557                 if (dsl_dataset_phys(ds)->ds_next_clones_obj &&
2558                     spa_version(dp->dp_spa) >= SPA_VERSION_DIR_CLONES) {
2559                         zap_cursor_t zc;
2560                         zap_attribute_t za;
2561 
2562                         for (zap_cursor_init(&zc, dp->dp_meta_objset,
2563                             dsl_dataset_phys(ds)->ds_next_clones_obj);
2564                             zap_cursor_retrieve(&zc, &za) == 0;
2565                             zap_cursor_advance(&zc)) {
2566                                 dsl_dataset_t *cnds;
2567                                 uint64_t o;
2568 
2569                                 if (za.za_first_integer == oldnext_obj) {
2570                                         /*
2571                                          * We've already moved the
2572                                          * origin's reference.
2573                                          */
2574                                         continue;
2575                                 }
2576 
2577                                 VERIFY0(dsl_dataset_hold_obj(dp,
2578                                     za.za_first_integer, FTAG, &cnds));
2579                                 o = dsl_dir_phys(cnds->ds_dir)->
2580                                     dd_head_dataset_obj;
2581 
2582                                 VERIFY0(zap_remove_int(dp->dp_meta_objset,
2583                                     dsl_dir_phys(odd)->dd_clones, o, tx));
2584                                 VERIFY0(zap_add_int(dp->dp_meta_objset,
2585                                     dsl_dir_phys(dd)->dd_clones, o, tx));
2586                                 dsl_dataset_rele(cnds, FTAG);
2587                         }
2588                         zap_cursor_fini(&zc);
2589                 }
2590 
2591                 ASSERT(!dsl_prop_hascb(ds));
2592         }
2593 
2594         /*
2595          * Change space accounting.
2596          * Note, pa->*usedsnap and dd_used_breakdown[SNAP] will either
2597          * both be valid, or both be 0 (resulting in delta == 0).  This
2598          * is true for each of {clone,origin} independently.
2599          */
2600 
2601         delta = ddpa->cloneusedsnap -
2602             dsl_dir_phys(dd)->dd_used_breakdown[DD_USED_SNAP];
2603         ASSERT3S(delta, >=, 0);
2604         ASSERT3U(ddpa->used, >=, delta);
2605         dsl_dir_diduse_space(dd, DD_USED_SNAP, delta, 0, 0, tx);
2606         dsl_dir_diduse_space(dd, DD_USED_HEAD,
2607             ddpa->used - delta, ddpa->comp, ddpa->uncomp, tx);
2608 
2609         delta = ddpa->originusedsnap -
2610             dsl_dir_phys(odd)->dd_used_breakdown[DD_USED_SNAP];
2611         ASSERT3S(delta, <=, 0);
2612         ASSERT3U(ddpa->used, >=, -delta);
2613         dsl_dir_diduse_space(odd, DD_USED_SNAP, delta, 0, 0, tx);
2614         dsl_dir_diduse_space(odd, DD_USED_HEAD,
2615             -ddpa->used - delta, -ddpa->comp, -ddpa->uncomp, tx);
2616 
2617         dsl_dataset_phys(origin_ds)->ds_unique_bytes = ddpa->unique;
2618 
2619         /* log history record */
2620         spa_history_log_internal_ds(hds, "promote", tx, "");
2621 
2622         dsl_dir_rele(odd, FTAG);
2623         promote_rele(ddpa, FTAG);
2624 }
2625 
2626 /*
2627  * Make a list of dsl_dataset_t's for the snapshots between first_obj
2628  * (exclusive) and last_obj (inclusive).  The list will be in reverse
2629  * order (last_obj will be the list_head()).  If first_obj == 0, do all
2630  * snapshots back to this dataset's origin.
2631  */
2632 static int
2633 snaplist_make(dsl_pool_t *dp,
2634     uint64_t first_obj, uint64_t last_obj, list_t *l, void *tag)
2635 {
2636         uint64_t obj = last_obj;
2637 
2638         list_create(l, sizeof (struct promotenode),
2639             offsetof(struct promotenode, link));
2640 
2641         while (obj != first_obj) {
2642                 dsl_dataset_t *ds;
2643                 struct promotenode *snap;
2644                 int err;
2645 
2646                 err = dsl_dataset_hold_obj(dp, obj, tag, &ds);
2647                 ASSERT(err != ENOENT);
2648                 if (err != 0)
2649                         return (err);
2650 
2651                 if (first_obj == 0)
2652                         first_obj = dsl_dir_phys(ds->ds_dir)->dd_origin_obj;
2653 
2654                 snap = kmem_alloc(sizeof (*snap), KM_SLEEP);
2655                 snap->ds = ds;
2656                 list_insert_tail(l, snap);
2657                 obj = dsl_dataset_phys(ds)->ds_prev_snap_obj;
2658         }
2659 
2660         return (0);
2661 }
2662 
2663 static int
2664 snaplist_space(list_t *l, uint64_t mintxg, uint64_t *spacep)
2665 {
2666         struct promotenode *snap;
2667 
2668         *spacep = 0;
2669         for (snap = list_head(l); snap; snap = list_next(l, snap)) {
2670                 uint64_t used, comp, uncomp;
2671                 dsl_deadlist_space_range(&snap->ds->ds_deadlist,
2672                     mintxg, UINT64_MAX, &used, &comp, &uncomp);
2673                 *spacep += used;
2674         }
2675         return (0);
2676 }
2677 
2678 static void
2679 snaplist_destroy(list_t *l, void *tag)
2680 {
2681         struct promotenode *snap;
2682 
2683         if (l == NULL || !list_link_active(&l->list_head))
2684                 return;
2685 
2686         while ((snap = list_tail(l)) != NULL) {
2687                 list_remove(l, snap);
2688                 dsl_dataset_rele(snap->ds, tag);
2689                 kmem_free(snap, sizeof (*snap));
2690         }
2691         list_destroy(l);
2692 }
2693 
2694 static int
2695 promote_hold(dsl_dataset_promote_arg_t *ddpa, dsl_pool_t *dp, void *tag)
2696 {
2697         int error;
2698         dsl_dir_t *dd;
2699         struct promotenode *snap;
2700 
2701         error = dsl_dataset_hold(dp, ddpa->ddpa_clonename, tag,
2702             &ddpa->ddpa_clone);
2703         if (error != 0)
2704                 return (error);
2705         dd = ddpa->ddpa_clone->ds_dir;
2706 
2707         if (ddpa->ddpa_clone->ds_is_snapshot ||
2708             !dsl_dir_is_clone(dd)) {
2709                 dsl_dataset_rele(ddpa->ddpa_clone, tag);
2710                 return (SET_ERROR(EINVAL));
2711         }
2712 
2713         error = snaplist_make(dp, 0, dsl_dir_phys(dd)->dd_origin_obj,
2714             &ddpa->shared_snaps, tag);
2715         if (error != 0)
2716                 goto out;
2717 
2718         error = snaplist_make(dp, 0, ddpa->ddpa_clone->ds_object,
2719             &ddpa->clone_snaps, tag);
2720         if (error != 0)
2721                 goto out;
2722 
2723         snap = list_head(&ddpa->shared_snaps);
2724         ASSERT3U(snap->ds->ds_object, ==, dsl_dir_phys(dd)->dd_origin_obj);
2725         error = snaplist_make(dp, dsl_dir_phys(dd)->dd_origin_obj,
2726             dsl_dir_phys(snap->ds->ds_dir)->dd_head_dataset_obj,
2727             &ddpa->origin_snaps, tag);
2728         if (error != 0)
2729                 goto out;
2730 
2731         if (dsl_dir_phys(snap->ds->ds_dir)->dd_origin_obj != 0) {
2732                 error = dsl_dataset_hold_obj(dp,
2733                     dsl_dir_phys(snap->ds->ds_dir)->dd_origin_obj,
2734                     tag, &ddpa->origin_origin);
2735                 if (error != 0)
2736                         goto out;
2737         }
2738 out:
2739         if (error != 0)
2740                 promote_rele(ddpa, tag);
2741         return (error);
2742 }
2743 
2744 static void
2745 promote_rele(dsl_dataset_promote_arg_t *ddpa, void *tag)
2746 {
2747         snaplist_destroy(&ddpa->shared_snaps, tag);
2748         snaplist_destroy(&ddpa->clone_snaps, tag);
2749         snaplist_destroy(&ddpa->origin_snaps, tag);
2750         if (ddpa->origin_origin != NULL)
2751                 dsl_dataset_rele(ddpa->origin_origin, tag);
2752         dsl_dataset_rele(ddpa->ddpa_clone, tag);
2753 }
2754 
2755 /*
2756  * Promote a clone.
2757  *
2758  * If it fails due to a conflicting snapshot name, "conflsnap" will be filled
2759  * in with the name.  (It must be at least MAXNAMELEN bytes long.)
2760  */
2761 int
2762 dsl_dataset_promote(const char *name, char *conflsnap)
2763 {
2764         dsl_dataset_promote_arg_t ddpa = { 0 };
2765         uint64_t numsnaps;
2766         int error;
2767         objset_t *os;
2768 
2769         /*
2770          * We will modify space proportional to the number of
2771          * snapshots.  Compute numsnaps.
2772          */
2773         error = dmu_objset_hold(name, FTAG, &os);
2774         if (error != 0)
2775                 return (error);
2776         error = zap_count(dmu_objset_pool(os)->dp_meta_objset,
2777             dsl_dataset_phys(dmu_objset_ds(os))->ds_snapnames_zapobj,
2778             &numsnaps);
2779         dmu_objset_rele(os, FTAG);
2780         if (error != 0)
2781                 return (error);
2782 
2783         ddpa.ddpa_clonename = name;
2784         ddpa.err_ds = conflsnap;
2785         ddpa.cr = CRED();
2786 
2787         return (dsl_sync_task(name, dsl_dataset_promote_check,
2788             dsl_dataset_promote_sync, &ddpa,
2789             2 + numsnaps, ZFS_SPACE_CHECK_RESERVED));
2790 }
2791 
2792 int
2793 dsl_dataset_clone_swap_check_impl(dsl_dataset_t *clone,
2794     dsl_dataset_t *origin_head, boolean_t force, void *owner, dmu_tx_t *tx)
2795 {
2796         int64_t unused_refres_delta;
2797 
2798         /* they should both be heads */
2799         if (clone->ds_is_snapshot ||
2800             origin_head->ds_is_snapshot)
2801                 return (SET_ERROR(EINVAL));
2802 
2803         /* if we are not forcing, the branch point should be just before them */
2804         if (!force && clone->ds_prev != origin_head->ds_prev)
2805                 return (SET_ERROR(EINVAL));
2806 
2807         /* clone should be the clone (unless they are unrelated) */
2808         if (clone->ds_prev != NULL &&
2809             clone->ds_prev != clone->ds_dir->dd_pool->dp_origin_snap &&
2810             origin_head->ds_dir != clone->ds_prev->ds_dir)
2811                 return (SET_ERROR(EINVAL));
2812 
2813         /* the clone should be a child of the origin */
2814         if (clone->ds_dir->dd_parent != origin_head->ds_dir)
2815                 return (SET_ERROR(EINVAL));
2816 
2817         /* origin_head shouldn't be modified unless 'force' */
2818         if (!force &&
2819             dsl_dataset_modified_since_snap(origin_head, origin_head->ds_prev))
2820                 return (SET_ERROR(ETXTBSY));
2821 
2822         /* origin_head should have no long holds (e.g. is not mounted) */
2823         if (dsl_dataset_handoff_check(origin_head, owner, tx))
2824                 return (SET_ERROR(EBUSY));
2825 
2826         /* check amount of any unconsumed refreservation */
2827         unused_refres_delta =
2828             (int64_t)MIN(origin_head->ds_reserved,
2829             dsl_dataset_phys(origin_head)->ds_unique_bytes) -
2830             (int64_t)MIN(origin_head->ds_reserved,
2831             dsl_dataset_phys(clone)->ds_unique_bytes);
2832 
2833         if (unused_refres_delta > 0 &&
2834             unused_refres_delta >
2835             dsl_dir_space_available(origin_head->ds_dir, NULL, 0, TRUE))
2836                 return (SET_ERROR(ENOSPC));
2837 
2838         /* clone can't be over the head's refquota */
2839         if (origin_head->ds_quota != 0 &&
2840             dsl_dataset_phys(clone)->ds_referenced_bytes >
2841             origin_head->ds_quota)
2842                 return (SET_ERROR(EDQUOT));
2843 
2844         return (0);
2845 }
2846 
2847 void
2848 dsl_dataset_clone_swap_sync_impl(dsl_dataset_t *clone,
2849     dsl_dataset_t *origin_head, dmu_tx_t *tx)
2850 {
2851         dsl_pool_t *dp = dmu_tx_pool(tx);
2852         int64_t unused_refres_delta;
2853 
2854         ASSERT(clone->ds_reserved == 0);
2855         ASSERT(origin_head->ds_quota == 0 ||
2856             dsl_dataset_phys(clone)->ds_unique_bytes <= origin_head->ds_quota);
2857         ASSERT3P(clone->ds_prev, ==, origin_head->ds_prev);
2858 
2859         /*
2860          * Swap per-dataset feature flags.
2861          */
2862         for (spa_feature_t f = 0; f < SPA_FEATURES; f++) {
2863                 if (!(spa_feature_table[f].fi_flags &
2864                     ZFEATURE_FLAG_PER_DATASET)) {
2865                         ASSERT(!clone->ds_feature_inuse[f]);
2866                         ASSERT(!origin_head->ds_feature_inuse[f]);
2867                         continue;
2868                 }
2869 
2870                 boolean_t clone_inuse = clone->ds_feature_inuse[f];
2871                 boolean_t origin_head_inuse = origin_head->ds_feature_inuse[f];
2872 
2873                 if (clone_inuse) {
2874                         dsl_dataset_deactivate_feature(clone->ds_object, f, tx);
2875                         clone->ds_feature_inuse[f] = B_FALSE;
2876                 }
2877                 if (origin_head_inuse) {
2878                         dsl_dataset_deactivate_feature(origin_head->ds_object,
2879                             f, tx);
2880                         origin_head->ds_feature_inuse[f] = B_FALSE;
2881                 }
2882                 if (clone_inuse) {
2883                         dsl_dataset_activate_feature(origin_head->ds_object,
2884                             f, tx);
2885                         origin_head->ds_feature_inuse[f] = B_TRUE;
2886                 }
2887                 if (origin_head_inuse) {
2888                         dsl_dataset_activate_feature(clone->ds_object, f, tx);
2889                         clone->ds_feature_inuse[f] = B_TRUE;
2890                 }
2891         }
2892 
2893         dmu_buf_will_dirty(clone->ds_dbuf, tx);
2894         dmu_buf_will_dirty(origin_head->ds_dbuf, tx);
2895 
2896         if (clone->ds_objset != NULL) {
2897                 dmu_objset_evict(clone->ds_objset);
2898                 clone->ds_objset = NULL;
2899         }
2900 
2901         if (origin_head->ds_objset != NULL) {
2902                 dmu_objset_evict(origin_head->ds_objset);
2903                 origin_head->ds_objset = NULL;
2904         }
2905 
2906         unused_refres_delta =
2907             (int64_t)MIN(origin_head->ds_reserved,
2908             dsl_dataset_phys(origin_head)->ds_unique_bytes) -
2909             (int64_t)MIN(origin_head->ds_reserved,
2910             dsl_dataset_phys(clone)->ds_unique_bytes);
2911 
2912         /*
2913          * Reset origin's unique bytes, if it exists.
2914          */
2915         if (clone->ds_prev) {
2916                 dsl_dataset_t *origin = clone->ds_prev;
2917                 uint64_t comp, uncomp;
2918 
2919                 dmu_buf_will_dirty(origin->ds_dbuf, tx);
2920                 dsl_deadlist_space_range(&clone->ds_deadlist,
2921                     dsl_dataset_phys(origin)->ds_prev_snap_txg, UINT64_MAX,
2922                     &dsl_dataset_phys(origin)->ds_unique_bytes, &comp, &uncomp);
2923         }
2924 
2925         /* swap blkptrs */
2926         {
2927                 blkptr_t tmp;
2928                 tmp = dsl_dataset_phys(origin_head)->ds_bp;
2929                 dsl_dataset_phys(origin_head)->ds_bp =
2930                     dsl_dataset_phys(clone)->ds_bp;
2931                 dsl_dataset_phys(clone)->ds_bp = tmp;
2932         }
2933 
2934         /* set dd_*_bytes */
2935         {
2936                 int64_t dused, dcomp, duncomp;
2937                 uint64_t cdl_used, cdl_comp, cdl_uncomp;
2938                 uint64_t odl_used, odl_comp, odl_uncomp;
2939 
2940                 ASSERT3U(dsl_dir_phys(clone->ds_dir)->
2941                     dd_used_breakdown[DD_USED_SNAP], ==, 0);
2942 
2943                 dsl_deadlist_space(&clone->ds_deadlist,
2944                     &cdl_used, &cdl_comp, &cdl_uncomp);
2945                 dsl_deadlist_space(&origin_head->ds_deadlist,
2946                     &odl_used, &odl_comp, &odl_uncomp);
2947 
2948                 dused = dsl_dataset_phys(clone)->ds_referenced_bytes +
2949                     cdl_used -
2950                     (dsl_dataset_phys(origin_head)->ds_referenced_bytes +
2951                     odl_used);
2952                 dcomp = dsl_dataset_phys(clone)->ds_compressed_bytes +
2953                     cdl_comp -
2954                     (dsl_dataset_phys(origin_head)->ds_compressed_bytes +
2955                     odl_comp);
2956                 duncomp = dsl_dataset_phys(clone)->ds_uncompressed_bytes +
2957                     cdl_uncomp -
2958                     (dsl_dataset_phys(origin_head)->ds_uncompressed_bytes +
2959                     odl_uncomp);
2960 
2961                 dsl_dir_diduse_space(origin_head->ds_dir, DD_USED_HEAD,
2962                     dused, dcomp, duncomp, tx);
2963                 dsl_dir_diduse_space(clone->ds_dir, DD_USED_HEAD,
2964                     -dused, -dcomp, -duncomp, tx);
2965 
2966                 /*
2967                  * The difference in the space used by snapshots is the
2968                  * difference in snapshot space due to the head's
2969                  * deadlist (since that's the only thing that's
2970                  * changing that affects the snapused).
2971                  */
2972                 dsl_deadlist_space_range(&clone->ds_deadlist,
2973                     origin_head->ds_dir->dd_origin_txg, UINT64_MAX,
2974                     &cdl_used, &cdl_comp, &cdl_uncomp);
2975                 dsl_deadlist_space_range(&origin_head->ds_deadlist,
2976                     origin_head->ds_dir->dd_origin_txg, UINT64_MAX,
2977                     &odl_used, &odl_comp, &odl_uncomp);
2978                 dsl_dir_transfer_space(origin_head->ds_dir, cdl_used - odl_used,
2979                     DD_USED_HEAD, DD_USED_SNAP, tx);
2980         }
2981 
2982         /* swap ds_*_bytes */
2983         SWITCH64(dsl_dataset_phys(origin_head)->ds_referenced_bytes,
2984             dsl_dataset_phys(clone)->ds_referenced_bytes);
2985         SWITCH64(dsl_dataset_phys(origin_head)->ds_compressed_bytes,
2986             dsl_dataset_phys(clone)->ds_compressed_bytes);
2987         SWITCH64(dsl_dataset_phys(origin_head)->ds_uncompressed_bytes,
2988             dsl_dataset_phys(clone)->ds_uncompressed_bytes);
2989         SWITCH64(dsl_dataset_phys(origin_head)->ds_unique_bytes,
2990             dsl_dataset_phys(clone)->ds_unique_bytes);
2991 
2992         /* apply any parent delta for change in unconsumed refreservation */
2993         dsl_dir_diduse_space(origin_head->ds_dir, DD_USED_REFRSRV,
2994             unused_refres_delta, 0, 0, tx);
2995 
2996         /*
2997          * Swap deadlists.
2998          */
2999         dsl_deadlist_close(&clone->ds_deadlist);
3000         dsl_deadlist_close(&origin_head->ds_deadlist);
3001         SWITCH64(dsl_dataset_phys(origin_head)->ds_deadlist_obj,
3002             dsl_dataset_phys(clone)->ds_deadlist_obj);
3003         dsl_deadlist_open(&clone->ds_deadlist, dp->dp_meta_objset,
3004             dsl_dataset_phys(clone)->ds_deadlist_obj);
3005         dsl_deadlist_open(&origin_head->ds_deadlist, dp->dp_meta_objset,
3006             dsl_dataset_phys(origin_head)->ds_deadlist_obj);
3007 
3008         dsl_scan_ds_clone_swapped(origin_head, clone, tx);
3009 
3010         spa_history_log_internal_ds(clone, "clone swap", tx,
3011             "parent=%s", origin_head->ds_dir->dd_myname);
3012 }
3013 
3014 /*
3015  * Given a pool name and a dataset object number in that pool,
3016  * return the name of that dataset.
3017  */
3018 int
3019 dsl_dsobj_to_dsname(char *pname, uint64_t obj, char *buf)
3020 {
3021         dsl_pool_t *dp;
3022         dsl_dataset_t *ds;
3023         int error;
3024 
3025         error = dsl_pool_hold(pname, FTAG, &dp);
3026         if (error != 0)
3027                 return (error);
3028 
3029         error = dsl_dataset_hold_obj(dp, obj, FTAG, &ds);
3030         if (error == 0) {
3031                 dsl_dataset_name(ds, buf);
3032                 dsl_dataset_rele(ds, FTAG);
3033         }
3034         dsl_pool_rele(dp, FTAG);
3035 
3036         return (error);
3037 }
3038 
3039 int
3040 dsl_dataset_check_quota(dsl_dataset_t *ds, boolean_t check_quota,
3041     uint64_t asize, uint64_t inflight, uint64_t *used, uint64_t *ref_rsrv)
3042 {
3043         int error = 0;
3044 
3045         ASSERT3S(asize, >, 0);
3046 
3047         /*
3048          * *ref_rsrv is the portion of asize that will come from any
3049          * unconsumed refreservation space.
3050          */
3051         *ref_rsrv = 0;
3052 
3053         mutex_enter(&ds->ds_lock);
3054         /*
3055          * Make a space adjustment for reserved bytes.
3056          */
3057         if (ds->ds_reserved > dsl_dataset_phys(ds)->ds_unique_bytes) {
3058                 ASSERT3U(*used, >=,
3059                     ds->ds_reserved - dsl_dataset_phys(ds)->ds_unique_bytes);
3060                 *used -=
3061                     (ds->ds_reserved - dsl_dataset_phys(ds)->ds_unique_bytes);
3062                 *ref_rsrv =
3063                     asize - MIN(asize, parent_delta(ds, asize + inflight));
3064         }
3065 
3066         if (!check_quota || ds->ds_quota == 0) {
3067                 mutex_exit(&ds->ds_lock);
3068                 return (0);
3069         }
3070         /*
3071          * If they are requesting more space, and our current estimate
3072          * is over quota, they get to try again unless the actual
3073          * on-disk is over quota and there are no pending changes (which
3074          * may free up space for us).
3075          */
3076         if (dsl_dataset_phys(ds)->ds_referenced_bytes + inflight >=
3077             ds->ds_quota) {
3078                 if (inflight > 0 ||
3079                     dsl_dataset_phys(ds)->ds_referenced_bytes < ds->ds_quota)
3080                         error = SET_ERROR(ERESTART);
3081                 else
3082                         error = SET_ERROR(EDQUOT);
3083         }
3084         mutex_exit(&ds->ds_lock);
3085 
3086         return (error);
3087 }
3088 
3089 typedef struct dsl_dataset_set_qr_arg {
3090         const char *ddsqra_name;
3091         zprop_source_t ddsqra_source;
3092         uint64_t ddsqra_value;
3093 } dsl_dataset_set_qr_arg_t;
3094 
3095 
3096 /* ARGSUSED */
3097 static int
3098 dsl_dataset_set_refquota_check(void *arg, dmu_tx_t *tx)
3099 {
3100         dsl_dataset_set_qr_arg_t *ddsqra = arg;
3101         dsl_pool_t *dp = dmu_tx_pool(tx);
3102         dsl_dataset_t *ds;
3103         int error;
3104         uint64_t newval;
3105 
3106         if (spa_version(dp->dp_spa) < SPA_VERSION_REFQUOTA)
3107                 return (SET_ERROR(ENOTSUP));
3108 
3109         error = dsl_dataset_hold(dp, ddsqra->ddsqra_name, FTAG, &ds);
3110         if (error != 0)
3111                 return (error);
3112 
3113         if (ds->ds_is_snapshot) {
3114                 dsl_dataset_rele(ds, FTAG);
3115                 return (SET_ERROR(EINVAL));
3116         }
3117 
3118         error = dsl_prop_predict(ds->ds_dir,
3119             zfs_prop_to_name(ZFS_PROP_REFQUOTA),
3120             ddsqra->ddsqra_source, ddsqra->ddsqra_value, &newval);
3121         if (error != 0) {
3122                 dsl_dataset_rele(ds, FTAG);
3123                 return (error);
3124         }
3125 
3126         if (newval == 0) {
3127                 dsl_dataset_rele(ds, FTAG);
3128                 return (0);
3129         }
3130 
3131         if (newval < dsl_dataset_phys(ds)->ds_referenced_bytes ||
3132             newval < ds->ds_reserved) {
3133                 dsl_dataset_rele(ds, FTAG);
3134                 return (SET_ERROR(ENOSPC));
3135         }
3136 
3137         dsl_dataset_rele(ds, FTAG);
3138         return (0);
3139 }
3140 
3141 static void
3142 dsl_dataset_set_refquota_sync(void *arg, dmu_tx_t *tx)
3143 {
3144         dsl_dataset_set_qr_arg_t *ddsqra = arg;
3145         dsl_pool_t *dp = dmu_tx_pool(tx);
3146         dsl_dataset_t *ds;
3147         uint64_t newval;
3148 
3149         VERIFY0(dsl_dataset_hold(dp, ddsqra->ddsqra_name, FTAG, &ds));
3150 
3151         dsl_prop_set_sync_impl(ds,
3152             zfs_prop_to_name(ZFS_PROP_REFQUOTA),
3153             ddsqra->ddsqra_source, sizeof (ddsqra->ddsqra_value), 1,
3154             &ddsqra->ddsqra_value, tx);
3155 
3156         VERIFY0(dsl_prop_get_int_ds(ds,
3157             zfs_prop_to_name(ZFS_PROP_REFQUOTA), &newval));
3158 
3159         if (ds->ds_quota != newval) {
3160                 dmu_buf_will_dirty(ds->ds_dbuf, tx);
3161                 ds->ds_quota = newval;
3162         }
3163         dsl_dataset_rele(ds, FTAG);
3164 }
3165 
3166 int
3167 dsl_dataset_set_refquota(const char *dsname, zprop_source_t source,
3168     uint64_t refquota)
3169 {
3170         dsl_dataset_set_qr_arg_t ddsqra;
3171 
3172         ddsqra.ddsqra_name = dsname;
3173         ddsqra.ddsqra_source = source;
3174         ddsqra.ddsqra_value = refquota;
3175 
3176         return (dsl_sync_task(dsname, dsl_dataset_set_refquota_check,
3177             dsl_dataset_set_refquota_sync, &ddsqra, 0, ZFS_SPACE_CHECK_NONE));
3178 }
3179 
3180 static int
3181 dsl_dataset_set_refreservation_check(void *arg, dmu_tx_t *tx)
3182 {
3183         dsl_dataset_set_qr_arg_t *ddsqra = arg;
3184         dsl_pool_t *dp = dmu_tx_pool(tx);
3185         dsl_dataset_t *ds;
3186         int error;
3187         uint64_t newval, unique;
3188 
3189         if (spa_version(dp->dp_spa) < SPA_VERSION_REFRESERVATION)
3190                 return (SET_ERROR(ENOTSUP));
3191 
3192         error = dsl_dataset_hold(dp, ddsqra->ddsqra_name, FTAG, &ds);
3193         if (error != 0)
3194                 return (error);
3195 
3196         if (ds->ds_is_snapshot) {
3197                 dsl_dataset_rele(ds, FTAG);
3198                 return (SET_ERROR(EINVAL));
3199         }
3200 
3201         error = dsl_prop_predict(ds->ds_dir,
3202             zfs_prop_to_name(ZFS_PROP_REFRESERVATION),
3203             ddsqra->ddsqra_source, ddsqra->ddsqra_value, &newval);
3204         if (error != 0) {
3205                 dsl_dataset_rele(ds, FTAG);
3206                 return (error);
3207         }
3208 
3209         /*
3210          * If we are doing the preliminary check in open context, the
3211          * space estimates may be inaccurate.
3212          */
3213         if (!dmu_tx_is_syncing(tx)) {
3214                 dsl_dataset_rele(ds, FTAG);
3215                 return (0);
3216         }
3217 
3218         mutex_enter(&ds->ds_lock);
3219         if (!DS_UNIQUE_IS_ACCURATE(ds))
3220                 dsl_dataset_recalc_head_uniq(ds);
3221         unique = dsl_dataset_phys(ds)->ds_unique_bytes;
3222         mutex_exit(&ds->ds_lock);
3223 
3224         if (MAX(unique, newval) > MAX(unique, ds->ds_reserved)) {
3225                 uint64_t delta = MAX(unique, newval) -
3226                     MAX(unique, ds->ds_reserved);
3227 
3228                 if (delta >
3229                     dsl_dir_space_available(ds->ds_dir, NULL, 0, B_TRUE) ||
3230                     (ds->ds_quota > 0 && newval > ds->ds_quota)) {
3231                         dsl_dataset_rele(ds, FTAG);
3232                         return (SET_ERROR(ENOSPC));
3233                 }
3234         }
3235 
3236         dsl_dataset_rele(ds, FTAG);
3237         return (0);
3238 }
3239 
3240 void
3241 dsl_dataset_set_refreservation_sync_impl(dsl_dataset_t *ds,
3242     zprop_source_t source, uint64_t value, dmu_tx_t *tx)
3243 {
3244         uint64_t newval;
3245         uint64_t unique;
3246         int64_t delta;
3247 
3248         dsl_prop_set_sync_impl(ds, zfs_prop_to_name(ZFS_PROP_REFRESERVATION),
3249             source, sizeof (value), 1, &value, tx);
3250 
3251         VERIFY0(dsl_prop_get_int_ds(ds,
3252             zfs_prop_to_name(ZFS_PROP_REFRESERVATION), &newval));
3253 
3254         dmu_buf_will_dirty(ds->ds_dbuf, tx);
3255         mutex_enter(&ds->ds_dir->dd_lock);
3256         mutex_enter(&ds->ds_lock);
3257         ASSERT(DS_UNIQUE_IS_ACCURATE(ds));
3258         unique = dsl_dataset_phys(ds)->ds_unique_bytes;
3259         delta = MAX(0, (int64_t)(newval - unique)) -
3260             MAX(0, (int64_t)(ds->ds_reserved - unique));
3261         ds->ds_reserved = newval;
3262         mutex_exit(&ds->ds_lock);
3263 
3264         dsl_dir_diduse_space(ds->ds_dir, DD_USED_REFRSRV, delta, 0, 0, tx);
3265         mutex_exit(&ds->ds_dir->dd_lock);
3266 }
3267 
3268 static void
3269 dsl_dataset_set_refreservation_sync(void *arg, dmu_tx_t *tx)
3270 {
3271         dsl_dataset_set_qr_arg_t *ddsqra = arg;
3272         dsl_pool_t *dp = dmu_tx_pool(tx);
3273         dsl_dataset_t *ds;
3274 
3275         VERIFY0(dsl_dataset_hold(dp, ddsqra->ddsqra_name, FTAG, &ds));
3276         dsl_dataset_set_refreservation_sync_impl(ds,
3277             ddsqra->ddsqra_source, ddsqra->ddsqra_value, tx);
3278         dsl_dataset_rele(ds, FTAG);
3279 }
3280 
3281 int
3282 dsl_dataset_set_refreservation(const char *dsname, zprop_source_t source,
3283     uint64_t refreservation)
3284 {
3285         dsl_dataset_set_qr_arg_t ddsqra;
3286 
3287         ddsqra.ddsqra_name = dsname;
3288         ddsqra.ddsqra_source = source;
3289         ddsqra.ddsqra_value = refreservation;
3290 
3291         return (dsl_sync_task(dsname, dsl_dataset_set_refreservation_check,
3292             dsl_dataset_set_refreservation_sync, &ddsqra,
3293             0, ZFS_SPACE_CHECK_NONE));
3294 }
3295 
3296 /*
3297  * Return (in *usedp) the amount of space written in new that is not
3298  * present in oldsnap.  New may be a snapshot or the head.  Old must be
3299  * a snapshot before new, in new's filesystem (or its origin).  If not then
3300  * fail and return EINVAL.
3301  *
3302  * The written space is calculated by considering two components:  First, we
3303  * ignore any freed space, and calculate the written as new's used space
3304  * minus old's used space.  Next, we add in the amount of space that was freed
3305  * between the two snapshots, thus reducing new's used space relative to old's.
3306  * Specifically, this is the space that was born before old->ds_creation_txg,
3307  * and freed before new (ie. on new's deadlist or a previous deadlist).
3308  *
3309  * space freed                         [---------------------]
3310  * snapshots                       ---O-------O--------O-------O------
3311  *                                         oldsnap            new
3312  */
3313 int
3314 dsl_dataset_space_written(dsl_dataset_t *oldsnap, dsl_dataset_t *new,
3315     uint64_t *usedp, uint64_t *compp, uint64_t *uncompp)
3316 {
3317         int err = 0;
3318         uint64_t snapobj;
3319         dsl_pool_t *dp = new->ds_dir->dd_pool;
3320 
3321         ASSERT(dsl_pool_config_held(dp));
3322 
3323         *usedp = 0;
3324         *usedp += dsl_dataset_phys(new)->ds_referenced_bytes;
3325         *usedp -= dsl_dataset_phys(oldsnap)->ds_referenced_bytes;
3326 
3327         *compp = 0;
3328         *compp += dsl_dataset_phys(new)->ds_compressed_bytes;
3329         *compp -= dsl_dataset_phys(oldsnap)->ds_compressed_bytes;
3330 
3331         *uncompp = 0;
3332         *uncompp += dsl_dataset_phys(new)->ds_uncompressed_bytes;
3333         *uncompp -= dsl_dataset_phys(oldsnap)->ds_uncompressed_bytes;
3334 
3335         snapobj = new->ds_object;
3336         while (snapobj != oldsnap->ds_object) {
3337                 dsl_dataset_t *snap;
3338                 uint64_t used, comp, uncomp;
3339 
3340                 if (snapobj == new->ds_object) {
3341                         snap = new;
3342                 } else {
3343                         err = dsl_dataset_hold_obj(dp, snapobj, FTAG, &snap);
3344                         if (err != 0)
3345                                 break;
3346                 }
3347 
3348                 if (dsl_dataset_phys(snap)->ds_prev_snap_txg ==
3349                     dsl_dataset_phys(oldsnap)->ds_creation_txg) {
3350                         /*
3351                          * The blocks in the deadlist can not be born after
3352                          * ds_prev_snap_txg, so get the whole deadlist space,
3353                          * which is more efficient (especially for old-format
3354                          * deadlists).  Unfortunately the deadlist code
3355                          * doesn't have enough information to make this
3356                          * optimization itself.
3357                          */
3358                         dsl_deadlist_space(&snap->ds_deadlist,
3359                             &used, &comp, &uncomp);
3360                 } else {
3361                         dsl_deadlist_space_range(&snap->ds_deadlist,
3362                             0, dsl_dataset_phys(oldsnap)->ds_creation_txg,
3363                             &used, &comp, &uncomp);
3364                 }
3365                 *usedp += used;
3366                 *compp += comp;
3367                 *uncompp += uncomp;
3368 
3369                 /*
3370                  * If we get to the beginning of the chain of snapshots
3371                  * (ds_prev_snap_obj == 0) before oldsnap, then oldsnap
3372                  * was not a snapshot of/before new.
3373                  */
3374                 snapobj = dsl_dataset_phys(snap)->ds_prev_snap_obj;
3375                 if (snap != new)
3376                         dsl_dataset_rele(snap, FTAG);
3377                 if (snapobj == 0) {
3378                         err = SET_ERROR(EINVAL);
3379                         break;
3380                 }
3381 
3382         }
3383         return (err);
3384 }
3385 
3386 /*
3387  * Return (in *usedp) the amount of space that will be reclaimed if firstsnap,
3388  * lastsnap, and all snapshots in between are deleted.
3389  *
3390  * blocks that would be freed            [---------------------------]
3391  * snapshots                       ---O-------O--------O-------O--------O
3392  *                                        firstsnap        lastsnap
3393  *
3394  * This is the set of blocks that were born after the snap before firstsnap,
3395  * (birth > firstsnap->prev_snap_txg) and died before the snap after the
3396  * last snap (ie, is on lastsnap->ds_next->ds_deadlist or an earlier deadlist).
3397  * We calculate this by iterating over the relevant deadlists (from the snap
3398  * after lastsnap, backward to the snap after firstsnap), summing up the
3399  * space on the deadlist that was born after the snap before firstsnap.
3400  */
3401 int
3402 dsl_dataset_space_wouldfree(dsl_dataset_t *firstsnap,
3403     dsl_dataset_t *lastsnap,
3404     uint64_t *usedp, uint64_t *compp, uint64_t *uncompp)
3405 {
3406         int err = 0;
3407         uint64_t snapobj;
3408         dsl_pool_t *dp = firstsnap->ds_dir->dd_pool;
3409 
3410         ASSERT(firstsnap->ds_is_snapshot);
3411         ASSERT(lastsnap->ds_is_snapshot);
3412 
3413         /*
3414          * Check that the snapshots are in the same dsl_dir, and firstsnap
3415          * is before lastsnap.
3416          */
3417         if (firstsnap->ds_dir != lastsnap->ds_dir ||
3418             dsl_dataset_phys(firstsnap)->ds_creation_txg >
3419             dsl_dataset_phys(lastsnap)->ds_creation_txg)
3420                 return (SET_ERROR(EINVAL));
3421 
3422         *usedp = *compp = *uncompp = 0;
3423 
3424         snapobj = dsl_dataset_phys(lastsnap)->ds_next_snap_obj;
3425         while (snapobj != firstsnap->ds_object) {
3426                 dsl_dataset_t *ds;
3427                 uint64_t used, comp, uncomp;
3428 
3429                 err = dsl_dataset_hold_obj(dp, snapobj, FTAG, &ds);
3430                 if (err != 0)
3431                         break;
3432 
3433                 dsl_deadlist_space_range(&ds->ds_deadlist,
3434                     dsl_dataset_phys(firstsnap)->ds_prev_snap_txg, UINT64_MAX,
3435                     &used, &comp, &uncomp);
3436                 *usedp += used;
3437                 *compp += comp;
3438                 *uncompp += uncomp;
3439 
3440                 snapobj = dsl_dataset_phys(ds)->ds_prev_snap_obj;
3441                 ASSERT3U(snapobj, !=, 0);
3442                 dsl_dataset_rele(ds, FTAG);
3443         }
3444         return (err);
3445 }
3446 
3447 /*
3448  * Return TRUE if 'earlier' is an earlier snapshot in 'later's timeline.
3449  * For example, they could both be snapshots of the same filesystem, and
3450  * 'earlier' is before 'later'.  Or 'earlier' could be the origin of
3451  * 'later's filesystem.  Or 'earlier' could be an older snapshot in the origin's
3452  * filesystem.  Or 'earlier' could be the origin's origin.
3453  *
3454  * If non-zero, earlier_txg is used instead of earlier's ds_creation_txg.
3455  */
3456 boolean_t
3457 dsl_dataset_is_before(dsl_dataset_t *later, dsl_dataset_t *earlier,
3458         uint64_t earlier_txg)
3459 {
3460         dsl_pool_t *dp = later->ds_dir->dd_pool;
3461         int error;
3462         boolean_t ret;
3463 
3464         ASSERT(dsl_pool_config_held(dp));
3465         ASSERT(earlier->ds_is_snapshot || earlier_txg != 0);
3466 
3467         if (earlier_txg == 0)
3468                 earlier_txg = dsl_dataset_phys(earlier)->ds_creation_txg;
3469 
3470         if (later->ds_is_snapshot &&
3471             earlier_txg >= dsl_dataset_phys(later)->ds_creation_txg)
3472                 return (B_FALSE);
3473 
3474         if (later->ds_dir == earlier->ds_dir)
3475                 return (B_TRUE);
3476         if (!dsl_dir_is_clone(later->ds_dir))
3477                 return (B_FALSE);
3478 
3479         if (dsl_dir_phys(later->ds_dir)->dd_origin_obj == earlier->ds_object)
3480                 return (B_TRUE);
3481         dsl_dataset_t *origin;
3482         error = dsl_dataset_hold_obj(dp,
3483             dsl_dir_phys(later->ds_dir)->dd_origin_obj, FTAG, &origin);
3484         if (error != 0)
3485                 return (B_FALSE);
3486         ret = dsl_dataset_is_before(origin, earlier, earlier_txg);
3487         dsl_dataset_rele(origin, FTAG);
3488         return (ret);
3489 }
3490 
3491 void
3492 dsl_dataset_zapify(dsl_dataset_t *ds, dmu_tx_t *tx)
3493 {
3494         objset_t *mos = ds->ds_dir->dd_pool->dp_meta_objset;
3495         dmu_object_zapify(mos, ds->ds_object, DMU_OT_DSL_DATASET, tx);
3496 }
3497 
3498 boolean_t
3499 dsl_dataset_is_zapified(dsl_dataset_t *ds)
3500 {
3501         dmu_object_info_t doi;
3502 
3503         dmu_object_info_from_db(ds->ds_dbuf, &doi);
3504         return (doi.doi_type == DMU_OTN_ZAP_METADATA);
3505 }
3506 
3507 boolean_t
3508 dsl_dataset_has_resume_receive_state(dsl_dataset_t *ds)
3509 {
3510         return (dsl_dataset_is_zapified(ds) &&
3511             zap_contains(ds->ds_dir->dd_pool->dp_meta_objset,
3512             ds->ds_object, DS_FIELD_RESUME_TOGUID) == 0);
3513 }