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