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