module/zfs/dmu_send.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21 /*
  22  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
  23  * Use is subject to license terms.
  24  */
  25
  26 #include <sys/dmu.h>
  27 #include <sys/dmu_impl.h>
  28 #include <sys/dmu_tx.h>
  29 #include <sys/dbuf.h>
  30 #include <sys/dnode.h>
  31 #include <sys/zfs_context.h>
  32 #include <sys/dmu_objset.h>
  33 #include <sys/dmu_traverse.h>
  34 #include <sys/dsl_dataset.h>
  35 #include <sys/dsl_dir.h>
  36 #include <sys/dsl_pool.h>
  37 #include <sys/dsl_synctask.h>
  38 #include <sys/zfs_ioctl.h>
  39 #include <sys/zap.h>
  40 #include <sys/zio_checksum.h>
  41
  42 static char *dmu_recv_tag = "dmu_recv_tag";
  43
  44 struct backuparg {
  45         dmu_replay_record_t *drr;
  46         vnode_t *vp;
  47         offset_t *off;
  48         objset_t *os;
  49         zio_cksum_t zc;
  50         int err;
  51 };
  52
  53 static int
  54 dump_bytes(struct backuparg *ba, void *buf, int len)
  55 {
  56         ssize_t resid; /* have to get resid to get detailed errno */
  57         ASSERT3U(len % 8, ==, 0);
  58
  59         fletcher_4_incremental_native(buf, len, &ba->zc);
  60         ba->err = vn_rdwr(UIO_WRITE, ba->vp,
  61             (caddr_t)buf, len,
  62             0, UIO_SYSSPACE, FAPPEND, RLIM64_INFINITY, CRED(), &resid);
  63         *ba->off += len;
  64         return (ba->err);
  65 }
  66
  67 static int
  68 dump_free(struct backuparg *ba, uint64_t object, uint64_t offset,
  69     uint64_t length)
  70 {
  71         /* write a FREE record */
  72         bzero(ba->drr, sizeof (dmu_replay_record_t));
  73         ba->drr->drr_type = DRR_FREE;
  74         ba->drr->drr_u.drr_free.drr_object = object;
  75         ba->drr->drr_u.drr_free.drr_offset = offset;
  76         ba->drr->drr_u.drr_free.drr_length = length;
  77
  78         if (dump_bytes(ba, ba->drr, sizeof (dmu_replay_record_t)))
  79                 return (EINTR);
  80         return (0);
  81 }
  82
  83 static int
  84 dump_data(struct backuparg *ba, dmu_object_type_t type,
  85     uint64_t object, uint64_t offset, int blksz, void *data)
  86 {
  87         /* write a DATA record */
  88         bzero(ba->drr, sizeof (dmu_replay_record_t));
  89         ba->drr->drr_type = DRR_WRITE;
  90         ba->drr->drr_u.drr_write.drr_object = object;
  91         ba->drr->drr_u.drr_write.drr_type = type;
  92         ba->drr->drr_u.drr_write.drr_offset = offset;
  93         ba->drr->drr_u.drr_write.drr_length = blksz;
  94
  95         if (dump_bytes(ba, ba->drr, sizeof (dmu_replay_record_t)))
  96                 return (EINTR);
  97         if (dump_bytes(ba, data, blksz))
  98                 return (EINTR);
  99         return (0);
 100 }
 101
 102 static int
 103 dump_freeobjects(struct backuparg *ba, uint64_t firstobj, uint64_t numobjs)
 104 {
 105         /* write a FREEOBJECTS record */
 106         bzero(ba->drr, sizeof (dmu_replay_record_t));
 107         ba->drr->drr_type = DRR_FREEOBJECTS;
 108         ba->drr->drr_u.drr_freeobjects.drr_firstobj = firstobj;
 109         ba->drr->drr_u.drr_freeobjects.drr_numobjs = numobjs;
 110
 111         if (dump_bytes(ba, ba->drr, sizeof (dmu_replay_record_t)))
 112                 return (EINTR);
 113         return (0);
 114 }
 115
 116 static int
 117 dump_dnode(struct backuparg *ba, uint64_t object, dnode_phys_t *dnp)
 118 {
 119         if (dnp == NULL || dnp->dn_type == DMU_OT_NONE)
 120                 return (dump_freeobjects(ba, object, 1));
 121
 122         /* write an OBJECT record */
 123         bzero(ba->drr, sizeof (dmu_replay_record_t));
 124         ba->drr->drr_type = DRR_OBJECT;
 125         ba->drr->drr_u.drr_object.drr_object = object;
 126         ba->drr->drr_u.drr_object.drr_type = dnp->dn_type;
 127         ba->drr->drr_u.drr_object.drr_bonustype = dnp->dn_bonustype;
 128         ba->drr->drr_u.drr_object.drr_blksz =
 129             dnp->dn_datablkszsec << SPA_MINBLOCKSHIFT;
 130         ba->drr->drr_u.drr_object.drr_bonuslen = dnp->dn_bonuslen;
 131         ba->drr->drr_u.drr_object.drr_checksum = dnp->dn_checksum;
 132         ba->drr->drr_u.drr_object.drr_compress = dnp->dn_compress;
 133
 134         if (dump_bytes(ba, ba->drr, sizeof (dmu_replay_record_t)))
 135                 return (EINTR);
 136
 137         if (dump_bytes(ba, DN_BONUS(dnp), P2ROUNDUP(dnp->dn_bonuslen, 8)))
 138                 return (EINTR);
 139
 140         /* free anything past the end of the file */
 141         if (dump_free(ba, object, (dnp->dn_maxblkid + 1) *
 142             (dnp->dn_datablkszsec << SPA_MINBLOCKSHIFT), -1ULL))
 143                 return (EINTR);
 144         if (ba->err)
 145                 return (EINTR);
 146         return (0);
 147 }
 148
 149 #define BP_SPAN(dnp, level) \
 150         (((uint64_t)dnp->dn_datablkszsec) << (SPA_MINBLOCKSHIFT + \
 151         (level) * (dnp->dn_indblkshift - SPA_BLKPTRSHIFT)))
 152
 153 static int
 154 backup_cb(spa_t *spa, blkptr_t *bp, const zbookmark_t *zb,
 155     const dnode_phys_t *dnp, void *arg)
 156 {
 157         struct backuparg *ba = arg;
 158         dmu_object_type_t type = bp ? BP_GET_TYPE(bp) : DMU_OT_NONE;
 159         int err = 0;
 160
 161         if (issig(JUSTLOOKING) && issig(FORREAL))
 162                 return (EINTR);
 163
 164         if (bp == NULL && zb->zb_object == 0) {
 165                 uint64_t span = BP_SPAN(dnp, zb->zb_level);
 166                 uint64_t dnobj = (zb->zb_blkid * span) >> DNODE_SHIFT;
 167                 err = dump_freeobjects(ba, dnobj, span >> DNODE_SHIFT);
 168         } else if (bp == NULL) {
 169                 uint64_t span = BP_SPAN(dnp, zb->zb_level);
 170                 err = dump_free(ba, zb->zb_object, zb->zb_blkid * span, span);
 171         } else if (zb->zb_level > 0 || type == DMU_OT_OBJSET) {
 172                 return (0);
 173         } else if (type == DMU_OT_DNODE) {
 174                 dnode_phys_t *blk;
 175                 int i;
 176                 int blksz = BP_GET_LSIZE(bp);
 177                 uint32_t aflags = ARC_WAIT;
 178                 arc_buf_t *abuf;
 179
 180                 if (arc_read_nolock(NULL, spa, bp,
 181                     arc_getbuf_func, &abuf, ZIO_PRIORITY_ASYNC_READ,
 182                     ZIO_FLAG_CANFAIL, &aflags, zb) != 0)
 183                         return (EIO);
 184
 185                 blk = abuf->b_data;
 186                 for (i = 0; i < blksz >> DNODE_SHIFT; i++) {
 187                         uint64_t dnobj = (zb->zb_blkid <<
 188                             (DNODE_BLOCK_SHIFT - DNODE_SHIFT)) + i;
 189                         err = dump_dnode(ba, dnobj, blk+i);
 190                         if (err)
 191                                 break;
 192                 }
 193                 (void) arc_buf_remove_ref(abuf, &abuf);
 194         } else { /* it's a level-0 block of a regular object */
 195                 uint32_t aflags = ARC_WAIT;
 196                 arc_buf_t *abuf;
 197                 int blksz = BP_GET_LSIZE(bp);
 198
 199                 if (arc_read_nolock(NULL, spa, bp,
 200                     arc_getbuf_func, &abuf, ZIO_PRIORITY_ASYNC_READ,
 201                     ZIO_FLAG_CANFAIL, &aflags, zb) != 0)
 202                         return (EIO);
 203
 204                 err = dump_data(ba, type, zb->zb_object, zb->zb_blkid * blksz,
 205                     blksz, abuf->b_data);
 206                 (void) arc_buf_remove_ref(abuf, &abuf);
 207         }
 208
 209         ASSERT(err == 0 || err == EINTR);
 210         return (err);
 211 }
 212
 213 int
 214 dmu_sendbackup(objset_t *tosnap, objset_t *fromsnap, boolean_t fromorigin,
 215     vnode_t *vp, offset_t *off)
 216 {
 217         dsl_dataset_t *ds = tosnap->os->os_dsl_dataset;
 218         dsl_dataset_t *fromds = fromsnap ? fromsnap->os->os_dsl_dataset : NULL;
 219         dmu_replay_record_t *drr;
 220         struct backuparg ba;
 221         int err;
 222         uint64_t fromtxg = 0;
 223
 224         /* tosnap must be a snapshot */
 225         if (ds->ds_phys->ds_next_snap_obj == 0)
 226                 return (EINVAL);
 227
 228         /* fromsnap must be an earlier snapshot from the same fs as tosnap */
 229         if (fromds && (ds->ds_dir != fromds->ds_dir ||
 230             fromds->ds_phys->ds_creation_txg >= ds->ds_phys->ds_creation_txg))
 231                 return (EXDEV);
 232
 233         if (fromorigin) {
 234                 dsl_pool_t *dp = ds->ds_dir->dd_pool;
 235
 236                 if (fromsnap)
 237                         return (EINVAL);
 238
 239                 if (dsl_dir_is_clone(ds->ds_dir)) {
 240                         rw_enter(&dp->dp_config_rwlock, RW_READER);
 241                         err = dsl_dataset_hold_obj(dp,
 242                             ds->ds_dir->dd_phys->dd_origin_obj, FTAG, &fromds);
 243                         rw_exit(&dp->dp_config_rwlock);
 244                         if (err)
 245                                 return (err);
 246                 } else {
 247                         fromorigin = B_FALSE;
 248                 }
 249         }
 250
 251
 252         drr = kmem_zalloc(sizeof (dmu_replay_record_t), KM_SLEEP);
 253         drr->drr_type = DRR_BEGIN;
 254         drr->drr_u.drr_begin.drr_magic = DMU_BACKUP_MAGIC;
 255         drr->drr_u.drr_begin.drr_version = DMU_BACKUP_STREAM_VERSION;
 256         drr->drr_u.drr_begin.drr_creation_time =
 257             ds->ds_phys->ds_creation_time;
 258         drr->drr_u.drr_begin.drr_type = tosnap->os->os_phys->os_type;
 259         if (fromorigin)
 260                 drr->drr_u.drr_begin.drr_flags |= DRR_FLAG_CLONE;
 261         drr->drr_u.drr_begin.drr_toguid = ds->ds_phys->ds_guid;
 262         if (ds->ds_phys->ds_flags & DS_FLAG_CI_DATASET)
 263                 drr->drr_u.drr_begin.drr_flags |= DRR_FLAG_CI_DATA;
 264
 265         if (fromds)
 266                 drr->drr_u.drr_begin.drr_fromguid = fromds->ds_phys->ds_guid;
 267         dsl_dataset_name(ds, drr->drr_u.drr_begin.drr_toname);
 268
 269         if (fromds)
 270                 fromtxg = fromds->ds_phys->ds_creation_txg;
 271         if (fromorigin)
 272                 dsl_dataset_rele(fromds, FTAG);
 273
 274         ba.drr = drr;
 275         ba.vp = vp;
 276         ba.os = tosnap;
 277         ba.off = off;
 278         ZIO_SET_CHECKSUM(&ba.zc, 0, 0, 0, 0);
 279
 280         if (dump_bytes(&ba, drr, sizeof (dmu_replay_record_t))) {
 281                 kmem_free(drr, sizeof (dmu_replay_record_t));
 282                 return (ba.err);
 283         }
 284
 285         err = traverse_dataset(ds, fromtxg, TRAVERSE_PRE | TRAVERSE_PREFETCH,
 286             backup_cb, &ba);
 287
 288         if (err) {
 289                 if (err == EINTR && ba.err)
 290                         err = ba.err;
 291                 kmem_free(drr, sizeof (dmu_replay_record_t));
 292                 return (err);
 293         }
 294
 295         bzero(drr, sizeof (dmu_replay_record_t));
 296         drr->drr_type = DRR_END;
 297         drr->drr_u.drr_end.drr_checksum = ba.zc;
 298
 299         if (dump_bytes(&ba, drr, sizeof (dmu_replay_record_t))) {
 300                 kmem_free(drr, sizeof (dmu_replay_record_t));
 301                 return (ba.err);
 302         }
 303
 304         kmem_free(drr, sizeof (dmu_replay_record_t));
 305
 306         return (0);
 307 }
 308
 309 struct recvbeginsyncarg {
 310         const char *tofs;
 311         const char *tosnap;
 312         dsl_dataset_t *origin;
 313         uint64_t fromguid;
 314         dmu_objset_type_t type;
 315         void *tag;
 316         boolean_t force;
 317         uint64_t dsflags;
 318         char clonelastname[MAXNAMELEN];
 319         dsl_dataset_t *ds; /* the ds to recv into; returned from the syncfunc */
 320 };
 321
 322 static dsl_dataset_t *
 323 recv_full_sync_impl(dsl_pool_t *dp, uint64_t dsobj, dmu_objset_type_t type,
 324     cred_t *cr, dmu_tx_t *tx)
 325 {
 326         dsl_dataset_t *ds;
 327
 328         /* This should always work, since we just created it */
 329         /* XXX - create should return an owned ds */
 330         VERIFY(0 == dsl_dataset_own_obj(dp, dsobj,
 331             DS_MODE_INCONSISTENT, dmu_recv_tag, &ds));
 332
 333         if (type != DMU_OST_NONE) {
 334                 (void) dmu_objset_create_impl(dp->dp_spa,
 335                     ds, &ds->ds_phys->ds_bp, type, tx);
 336         }
 337
 338         spa_history_internal_log(LOG_DS_REPLAY_FULL_SYNC,
 339             dp->dp_spa, tx, cr, "dataset = %lld", dsobj);
 340
 341         return (ds);
 342 }
 343
 344 /* ARGSUSED */
 345 static int
 346 recv_full_check(void *arg1, void *arg2, dmu_tx_t *tx)
 347 {
 348         dsl_dir_t *dd = arg1;
 349         struct recvbeginsyncarg *rbsa = arg2;
 350         objset_t *mos = dd->dd_pool->dp_meta_objset;
 351         uint64_t val;
 352         int err;
 353
 354         err = zap_lookup(mos, dd->dd_phys->dd_child_dir_zapobj,
 355             strrchr(rbsa->tofs, '/') + 1, sizeof (uint64_t), 1, &val);
 356
 357         if (err != ENOENT)
 358                 return (err ? err : EEXIST);
 359
 360         if (rbsa->origin) {
 361                 /* make sure it's a snap in the same pool */
 362                 if (rbsa->origin->ds_dir->dd_pool != dd->dd_pool)
 363                         return (EXDEV);
 364                 if (rbsa->origin->ds_phys->ds_num_children == 0)
 365                         return (EINVAL);
 366                 if (rbsa->origin->ds_phys->ds_guid != rbsa->fromguid)
 367                         return (ENODEV);
 368         }
 369
 370         return (0);
 371 }
 372
 373 static void
 374 recv_full_sync(void *arg1, void *arg2, cred_t *cr, dmu_tx_t *tx)
 375 {
 376         dsl_dir_t *dd = arg1;
 377         struct recvbeginsyncarg *rbsa = arg2;
 378         uint64_t flags = DS_FLAG_INCONSISTENT | rbsa->dsflags;
 379         uint64_t dsobj;
 380
 381         dsobj = dsl_dataset_create_sync(dd, strrchr(rbsa->tofs, '/') + 1,
 382             rbsa->origin, flags, cr, tx);
 383
 384         rbsa->ds = recv_full_sync_impl(dd->dd_pool, dsobj,
 385             rbsa->origin ? DMU_OST_NONE : rbsa->type, cr, tx);
 386 }
 387
 388 static int
 389 recv_full_existing_check(void *arg1, void *arg2, dmu_tx_t *tx)
 390 {
 391         dsl_dataset_t *ds = arg1;
 392         struct recvbeginsyncarg *rbsa = arg2;
 393         int err;
 394
 395         /* must be a head ds */
 396         if (ds->ds_phys->ds_next_snap_obj != 0)
 397                 return (EINVAL);
 398
 399         /* must not be a clone ds */
 400         if (dsl_dir_is_clone(ds->ds_dir))
 401                 return (EINVAL);
 402
 403         err = dsl_dataset_destroy_check(ds, rbsa->tag, tx);
 404         if (err)
 405                 return (err);
 406
 407         if (rbsa->origin) {
 408                 /* make sure it's a snap in the same pool */
 409                 if (rbsa->origin->ds_dir->dd_pool != ds->ds_dir->dd_pool)
 410                         return (EXDEV);
 411                 if (rbsa->origin->ds_phys->ds_num_children == 0)
 412                         return (EINVAL);
 413                 if (rbsa->origin->ds_phys->ds_guid != rbsa->fromguid)
 414                         return (ENODEV);
 415         }
 416
 417         return (0);
 418 }
 419
 420 static void
 421 recv_full_existing_sync(void *arg1, void *arg2, cred_t *cr, dmu_tx_t *tx)
 422 {
 423         dsl_dataset_t *ds = arg1;
 424         struct recvbeginsyncarg *rbsa = arg2;
 425         dsl_dir_t *dd = ds->ds_dir;
 426         uint64_t flags = DS_FLAG_INCONSISTENT | rbsa->dsflags;
 427         uint64_t dsobj;
 428
 429         /*
 430          * NB: caller must provide an extra hold on the dsl_dir_t, so it
 431          * won't go away when dsl_dataset_destroy_sync() closes the
 432          * dataset.
 433          */
 434         dsl_dataset_destroy_sync(ds, rbsa->tag, cr, tx);
 435
 436         dsobj = dsl_dataset_create_sync_dd(dd, rbsa->origin, flags, tx);
 437
 438         rbsa->ds = recv_full_sync_impl(dd->dd_pool, dsobj,
 439             rbsa->origin ? DMU_OST_NONE : rbsa->type, cr, tx);
 440 }
 441
 442 /* ARGSUSED */
 443 static int
 444 recv_incremental_check(void *arg1, void *arg2, dmu_tx_t *tx)
 445 {
 446         dsl_dataset_t *ds = arg1;
 447         struct recvbeginsyncarg *rbsa = arg2;
 448         int err;
 449         uint64_t val;
 450
 451         /* must not have any changes since most recent snapshot */
 452         if (!rbsa->force && dsl_dataset_modified_since_lastsnap(ds))
 453                 return (ETXTBSY);
 454
 455         /* must already be a snapshot of this fs */
 456         if (ds->ds_phys->ds_prev_snap_obj == 0)
 457                 return (ENODEV);
 458
 459         /* most recent snapshot must match fromguid */
 460         if (ds->ds_prev->ds_phys->ds_guid != rbsa->fromguid)
 461                 return (ENODEV);
 462
 463         /* temporary clone name must not exist */
 464         err = zap_lookup(ds->ds_dir->dd_pool->dp_meta_objset,
 465             ds->ds_dir->dd_phys->dd_child_dir_zapobj,
 466             rbsa->clonelastname, 8, 1, &val);
 467         if (err == 0)
 468                 return (EEXIST);
 469         if (err != ENOENT)
 470                 return (err);
 471
 472         /* new snapshot name must not exist */
 473         err = zap_lookup(ds->ds_dir->dd_pool->dp_meta_objset,
 474             ds->ds_phys->ds_snapnames_zapobj, rbsa->tosnap, 8, 1, &val);
 475         if (err == 0)
 476                 return (EEXIST);
 477         if (err != ENOENT)
 478                 return (err);
 479         return (0);
 480 }
 481
 482 /* ARGSUSED */
 483 static void
 484 recv_online_incremental_sync(void *arg1, void *arg2, cred_t *cr, dmu_tx_t *tx)
 485 {
 486         dsl_dataset_t *ohds = arg1;
 487         struct recvbeginsyncarg *rbsa = arg2;
 488         dsl_pool_t *dp = ohds->ds_dir->dd_pool;
 489         dsl_dataset_t *ods, *cds;
 490         uint64_t flags = DS_FLAG_INCONSISTENT | rbsa->dsflags;
 491         uint64_t dsobj;
 492
 493         /* create the temporary clone */
 494         VERIFY(0 == dsl_dataset_hold_obj(dp, ohds->ds_phys->ds_prev_snap_obj,
 495             FTAG, &ods));
 496         dsobj = dsl_dataset_create_sync(ohds->ds_dir,
 497             rbsa->clonelastname, ods, flags, cr, tx);
 498         dsl_dataset_rele(ods, FTAG);
 499
 500         /* open the temporary clone */
 501         VERIFY(0 == dsl_dataset_own_obj(dp, dsobj,
 502             DS_MODE_INCONSISTENT, dmu_recv_tag, &cds));
 503
 504         /* copy the refquota from the target fs to the clone */
 505         if (ohds->ds_quota > 0)
 506                 dsl_dataset_set_quota_sync(cds, &ohds->ds_quota, cr, tx);
 507
 508         rbsa->ds = cds;
 509
 510         spa_history_internal_log(LOG_DS_REPLAY_INC_SYNC,
 511             dp->dp_spa, tx, cr, "dataset = %lld", dsobj);
 512 }
 513
 514 /* ARGSUSED */
 515 static void
 516 recv_offline_incremental_sync(void *arg1, void *arg2, cred_t *cr, dmu_tx_t *tx)
 517 {
 518         dsl_dataset_t *ds = arg1;
 519
 520         dmu_buf_will_dirty(ds->ds_dbuf, tx);
 521         ds->ds_phys->ds_flags |= DS_FLAG_INCONSISTENT;
 522
 523         spa_history_internal_log(LOG_DS_REPLAY_INC_SYNC,
 524             ds->ds_dir->dd_pool->dp_spa, tx, cr, "dataset = %lld",
 525             ds->ds_object);
 526 }
 527
 528 /*
 529  * NB: callers *MUST* call dmu_recv_stream() if dmu_recv_begin()
 530  * succeeds; otherwise we will leak the holds on the datasets.
 531  */
 532 int
 533 dmu_recv_begin(char *tofs, char *tosnap, struct drr_begin *drrb,
 534     boolean_t force, objset_t *origin, boolean_t online, dmu_recv_cookie_t *drc)
 535 {
 536         int err = 0;
 537         boolean_t byteswap;
 538         struct recvbeginsyncarg rbsa;
 539         uint64_t version;
 540         int flags;
 541         dsl_dataset_t *ds;
 542
 543         if (drrb->drr_magic == DMU_BACKUP_MAGIC)
 544                 byteswap = FALSE;
 545         else if (drrb->drr_magic == BSWAP_64(DMU_BACKUP_MAGIC))
 546                 byteswap = TRUE;
 547         else
 548                 return (EINVAL);
 549
 550         rbsa.tofs = tofs;
 551         rbsa.tosnap = tosnap;
 552         rbsa.origin = origin ? origin->os->os_dsl_dataset : NULL;
 553         rbsa.fromguid = drrb->drr_fromguid;
 554         rbsa.type = drrb->drr_type;
 555         rbsa.tag = FTAG;
 556         rbsa.dsflags = 0;
 557         version = drrb->drr_version;
 558         flags = drrb->drr_flags;
 559
 560         if (byteswap) {
 561                 rbsa.type = BSWAP_32(rbsa.type);
 562                 rbsa.fromguid = BSWAP_64(rbsa.fromguid);
 563                 version = BSWAP_64(version);
 564                 flags = BSWAP_32(flags);
 565         }
 566
 567         if (version != DMU_BACKUP_STREAM_VERSION ||
 568             rbsa.type >= DMU_OST_NUMTYPES ||
 569             ((flags & DRR_FLAG_CLONE) && origin == NULL))
 570                 return (EINVAL);
 571
 572         if (flags & DRR_FLAG_CI_DATA)
 573                 rbsa.dsflags = DS_FLAG_CI_DATASET;
 574
 575         bzero(drc, sizeof (dmu_recv_cookie_t));
 576         drc->drc_drrb = drrb;
 577         drc->drc_tosnap = tosnap;
 578         drc->drc_force = force;
 579
 580         /*
 581          * Process the begin in syncing context.
 582          */
 583         if (rbsa.fromguid && !(flags & DRR_FLAG_CLONE) && !online) {
 584                 /* offline incremental receive */
 585                 err = dsl_dataset_own(tofs, 0, dmu_recv_tag, &ds);
 586                 if (err)
 587                         return (err);
 588
 589                 /*
 590                  * Only do the rollback if the most recent snapshot
 591                  * matches the incremental source
 592                  */
 593                 if (force) {
 594                         if (ds->ds_prev == NULL ||
 595                             ds->ds_prev->ds_phys->ds_guid !=
 596                             rbsa.fromguid) {
 597                                 dsl_dataset_disown(ds, dmu_recv_tag);
 598                                 return (ENODEV);
 599                         }
 600                         (void) dsl_dataset_rollback(ds, DMU_OST_NONE);
 601                 }
 602                 rbsa.force = B_FALSE;
 603                 err = dsl_sync_task_do(ds->ds_dir->dd_pool,
 604                     recv_incremental_check,
 605                     recv_offline_incremental_sync, ds, &rbsa, 1);
 606                 if (err) {
 607                         dsl_dataset_disown(ds, dmu_recv_tag);
 608                         return (err);
 609                 }
 610                 drc->drc_logical_ds = drc->drc_real_ds = ds;
 611         } else if (rbsa.fromguid && !(flags & DRR_FLAG_CLONE)) {
 612                 /* online incremental receive */
 613
 614                 /* tmp clone name is: tofs/%tosnap" */
 615                 (void) snprintf(rbsa.clonelastname, sizeof (rbsa.clonelastname),
 616                     "%%%s", tosnap);
 617
 618                 /* open the dataset we are logically receiving into */
 619                 err = dsl_dataset_hold(tofs, dmu_recv_tag, &ds);
 620                 if (err)
 621                         return (err);
 622
 623                 rbsa.force = force;
 624                 err = dsl_sync_task_do(ds->ds_dir->dd_pool,
 625                     recv_incremental_check,
 626                     recv_online_incremental_sync, ds, &rbsa, 5);
 627                 if (err) {
 628                         dsl_dataset_rele(ds, dmu_recv_tag);
 629                         return (err);
 630                 }
 631                 drc->drc_logical_ds = ds;
 632                 drc->drc_real_ds = rbsa.ds;
 633         } else {
 634                 /* create new fs -- full backup or clone */
 635                 dsl_dir_t *dd = NULL;
 636                 const char *tail;
 637
 638                 err = dsl_dir_open(tofs, FTAG, &dd, &tail);
 639                 if (err)
 640                         return (err);
 641                 if (tail == NULL) {
 642                         if (!force) {
 643                                 dsl_dir_close(dd, FTAG);
 644                                 return (EEXIST);
 645                         }
 646
 647                         rw_enter(&dd->dd_pool->dp_config_rwlock, RW_READER);
 648                         err = dsl_dataset_own_obj(dd->dd_pool,
 649                             dd->dd_phys->dd_head_dataset_obj,
 650                             DS_MODE_INCONSISTENT, FTAG, &ds);
 651                         rw_exit(&dd->dd_pool->dp_config_rwlock);
 652                         if (err) {
 653                                 dsl_dir_close(dd, FTAG);
 654                                 return (err);
 655                         }
 656
 657                         dsl_dataset_make_exclusive(ds, FTAG);
 658                         err = dsl_sync_task_do(dd->dd_pool,
 659                             recv_full_existing_check,
 660                             recv_full_existing_sync, ds, &rbsa, 5);
 661                         dsl_dataset_disown(ds, FTAG);
 662                 } else {
 663                         err = dsl_sync_task_do(dd->dd_pool, recv_full_check,
 664                             recv_full_sync, dd, &rbsa, 5);
 665                 }
 666                 dsl_dir_close(dd, FTAG);
 667                 if (err)
 668                         return (err);
 669                 drc->drc_logical_ds = drc->drc_real_ds = rbsa.ds;
 670                 drc->drc_newfs = B_TRUE;
 671         }
 672
 673         return (0);
 674 }
 675
 676 struct restorearg {
 677         int err;
 678         int byteswap;
 679         vnode_t *vp;
 680         char *buf;
 681         uint64_t voff;
 682         int bufsize; /* amount of memory allocated for buf */
 683         zio_cksum_t cksum;
 684 };
 685
 686 static void *
 687 restore_read(struct restorearg *ra, int len)
 688 {
 689         void *rv;
 690         int done = 0;
 691
 692         /* some things will require 8-byte alignment, so everything must */
 693         ASSERT3U(len % 8, ==, 0);
 694
 695         while (done < len) {
 696                 ssize_t resid;
 697
 698                 ra->err = vn_rdwr(UIO_READ, ra->vp,
 699                     (caddr_t)ra->buf + done, len - done,
 700                     ra->voff, UIO_SYSSPACE, FAPPEND,
 701                     RLIM64_INFINITY, CRED(), &resid);
 702
 703                 if (resid == len - done)
 704                         ra->err = EINVAL;
 705                 ra->voff += len - done - resid;
 706                 done = len - resid;
 707                 if (ra->err)
 708                         return (NULL);
 709         }
 710
 711         ASSERT3U(done, ==, len);
 712         rv = ra->buf;
 713         if (ra->byteswap)
 714                 fletcher_4_incremental_byteswap(rv, len, &ra->cksum);
 715         else
 716                 fletcher_4_incremental_native(rv, len, &ra->cksum);
 717         return (rv);
 718 }
 719
 720 static void
 721 backup_byteswap(dmu_replay_record_t *drr)
 722 {
 723 #define DO64(X) (drr->drr_u.X = BSWAP_64(drr->drr_u.X))
 724 #define DO32(X) (drr->drr_u.X = BSWAP_32(drr->drr_u.X))
 725         drr->drr_type = BSWAP_32(drr->drr_type);
 726         drr->drr_payloadlen = BSWAP_32(drr->drr_payloadlen);
 727         switch (drr->drr_type) {
 728         case DRR_BEGIN:
 729                 DO64(drr_begin.drr_magic);
 730                 DO64(drr_begin.drr_version);
 731                 DO64(drr_begin.drr_creation_time);
 732                 DO32(drr_begin.drr_type);
 733                 DO32(drr_begin.drr_flags);
 734                 DO64(drr_begin.drr_toguid);
 735                 DO64(drr_begin.drr_fromguid);
 736                 break;
 737         case DRR_OBJECT:
 738                 DO64(drr_object.drr_object);
 739                 /* DO64(drr_object.drr_allocation_txg); */
 740                 DO32(drr_object.drr_type);
 741                 DO32(drr_object.drr_bonustype);
 742                 DO32(drr_object.drr_blksz);
 743                 DO32(drr_object.drr_bonuslen);
 744                 break;
 745         case DRR_FREEOBJECTS:
 746                 DO64(drr_freeobjects.drr_firstobj);
 747                 DO64(drr_freeobjects.drr_numobjs);
 748                 break;
 749         case DRR_WRITE:
 750                 DO64(drr_write.drr_object);
 751                 DO32(drr_write.drr_type);
 752                 DO64(drr_write.drr_offset);
 753                 DO64(drr_write.drr_length);
 754                 break;
 755         case DRR_FREE:
 756                 DO64(drr_free.drr_object);
 757                 DO64(drr_free.drr_offset);
 758                 DO64(drr_free.drr_length);
 759                 break;
 760         case DRR_END:
 761                 DO64(drr_end.drr_checksum.zc_word[0]);
 762                 DO64(drr_end.drr_checksum.zc_word[1]);
 763                 DO64(drr_end.drr_checksum.zc_word[2]);
 764                 DO64(drr_end.drr_checksum.zc_word[3]);
 765                 break;
 766         }
 767 #undef DO64
 768 #undef DO32
 769 }
 770
 771 static int
 772 restore_object(struct restorearg *ra, objset_t *os, struct drr_object *drro)
 773 {
 774         int err;
 775         dmu_tx_t *tx;
 776         void *data = NULL;
 777
 778         err = dmu_object_info(os, drro->drr_object, NULL);
 779
 780         if (err != 0 && err != ENOENT)
 781                 return (EINVAL);
 782
 783         if (drro->drr_type == DMU_OT_NONE ||
 784             drro->drr_type >= DMU_OT_NUMTYPES ||
 785             drro->drr_bonustype >= DMU_OT_NUMTYPES ||
 786             drro->drr_checksum >= ZIO_CHECKSUM_FUNCTIONS ||
 787             drro->drr_compress >= ZIO_COMPRESS_FUNCTIONS ||
 788             P2PHASE(drro->drr_blksz, SPA_MINBLOCKSIZE) ||
 789             drro->drr_blksz < SPA_MINBLOCKSIZE ||
 790             drro->drr_blksz > SPA_MAXBLOCKSIZE ||
 791             drro->drr_bonuslen > DN_MAX_BONUSLEN) {
 792                 return (EINVAL);
 793         }
 794
 795         if (drro->drr_bonuslen) {
 796                 data = restore_read(ra, P2ROUNDUP(drro->drr_bonuslen, 8));
 797                 if (ra->err)
 798                         return (ra->err);
 799         }
 800
 801         tx = dmu_tx_create(os);
 802
 803         if (err == ENOENT) {
 804                 /* currently free, want to be allocated */
 805                 dmu_tx_hold_bonus(tx, DMU_NEW_OBJECT);
 806                 dmu_tx_hold_write(tx, DMU_NEW_OBJECT, 0, 1);
 807                 err = dmu_tx_assign(tx, TXG_WAIT);
 808                 if (err) {
 809                         dmu_tx_abort(tx);
 810                         return (err);
 811                 }
 812                 err = dmu_object_claim(os, drro->drr_object,
 813                     drro->drr_type, drro->drr_blksz,
 814                     drro->drr_bonustype, drro->drr_bonuslen, tx);
 815         } else {
 816                 /* currently allocated, want to be allocated */
 817                 dmu_tx_hold_bonus(tx, drro->drr_object);
 818                 /*
 819                  * We may change blocksize, so need to
 820                  * hold_write
 821                  */
 822                 dmu_tx_hold_write(tx, drro->drr_object, 0, 1);
 823                 err = dmu_tx_assign(tx, TXG_WAIT);
 824                 if (err) {
 825                         dmu_tx_abort(tx);
 826                         return (err);
 827                 }
 828
 829                 err = dmu_object_reclaim(os, drro->drr_object,
 830                     drro->drr_type, drro->drr_blksz,
 831                     drro->drr_bonustype, drro->drr_bonuslen, tx);
 832         }
 833         if (err) {
 834                 dmu_tx_commit(tx);
 835                 return (EINVAL);
 836         }
 837
 838         dmu_object_set_checksum(os, drro->drr_object, drro->drr_checksum, tx);
 839         dmu_object_set_compress(os, drro->drr_object, drro->drr_compress, tx);
 840
 841         if (data != NULL) {
 842                 dmu_buf_t *db;
 843
 844                 VERIFY(0 == dmu_bonus_hold(os, drro->drr_object, FTAG, &db));
 845                 dmu_buf_will_dirty(db, tx);
 846
 847                 ASSERT3U(db->db_size, >=, drro->drr_bonuslen);
 848                 bcopy(data, db->db_data, drro->drr_bonuslen);
 849                 if (ra->byteswap) {
 850                         dmu_ot[drro->drr_bonustype].ot_byteswap(db->db_data,
 851                             drro->drr_bonuslen);
 852                 }
 853                 dmu_buf_rele(db, FTAG);
 854         }
 855         dmu_tx_commit(tx);
 856         return (0);
 857 }
 858
 859 /* ARGSUSED */
 860 static int
 861 restore_freeobjects(struct restorearg *ra, objset_t *os,
 862     struct drr_freeobjects *drrfo)
 863 {
 864         uint64_t obj;
 865
 866         if (drrfo->drr_firstobj + drrfo->drr_numobjs < drrfo->drr_firstobj)
 867                 return (EINVAL);
 868
 869         for (obj = drrfo->drr_firstobj;
 870             obj < drrfo->drr_firstobj + drrfo->drr_numobjs;
 871             (void) dmu_object_next(os, &obj, FALSE, 0)) {
 872                 int err;
 873
 874                 if (dmu_object_info(os, obj, NULL) != 0)
 875                         continue;
 876
 877                 err = dmu_free_object(os, obj);
 878                 if (err)
 879                         return (err);
 880         }
 881         return (0);
 882 }
 883
 884 static int
 885 restore_write(struct restorearg *ra, objset_t *os,
 886     struct drr_write *drrw)
 887 {
 888         dmu_tx_t *tx;
 889         void *data;
 890         int err;
 891
 892         if (drrw->drr_offset + drrw->drr_length < drrw->drr_offset ||
 893             drrw->drr_type >= DMU_OT_NUMTYPES)
 894                 return (EINVAL);
 895
 896         data = restore_read(ra, drrw->drr_length);
 897         if (data == NULL)
 898                 return (ra->err);
 899
 900         if (dmu_object_info(os, drrw->drr_object, NULL) != 0)
 901                 return (EINVAL);
 902
 903         tx = dmu_tx_create(os);
 904
 905         dmu_tx_hold_write(tx, drrw->drr_object,
 906             drrw->drr_offset, drrw->drr_length);
 907         err = dmu_tx_assign(tx, TXG_WAIT);
 908         if (err) {
 909                 dmu_tx_abort(tx);
 910                 return (err);
 911         }
 912         if (ra->byteswap)
 913                 dmu_ot[drrw->drr_type].ot_byteswap(data, drrw->drr_length);
 914         dmu_write(os, drrw->drr_object,
 915             drrw->drr_offset, drrw->drr_length, data, tx);
 916         dmu_tx_commit(tx);
 917         return (0);
 918 }
 919
 920 /* ARGSUSED */
 921 static int
 922 restore_free(struct restorearg *ra, objset_t *os,
 923     struct drr_free *drrf)
 924 {
 925         int err;
 926
 927         if (drrf->drr_length != -1ULL &&
 928             drrf->drr_offset + drrf->drr_length < drrf->drr_offset)
 929                 return (EINVAL);
 930
 931         if (dmu_object_info(os, drrf->drr_object, NULL) != 0)
 932                 return (EINVAL);
 933
 934         err = dmu_free_long_range(os, drrf->drr_object,
 935             drrf->drr_offset, drrf->drr_length);
 936         return (err);
 937 }
 938
 939 void
 940 dmu_recv_abort_cleanup(dmu_recv_cookie_t *drc)
 941 {
 942         if (drc->drc_newfs || drc->drc_real_ds != drc->drc_logical_ds) {
 943                 /*
 944                  * online incremental or new fs: destroy the fs (which
 945                  * may be a clone) that we created
 946                  */
 947                 (void) dsl_dataset_destroy(drc->drc_real_ds, dmu_recv_tag);
 948                 if (drc->drc_real_ds != drc->drc_logical_ds)
 949                         dsl_dataset_rele(drc->drc_logical_ds, dmu_recv_tag);
 950         } else {
 951                 /*
 952                  * offline incremental: rollback to most recent snapshot.
 953                  */
 954                 (void) dsl_dataset_rollback(drc->drc_real_ds, DMU_OST_NONE);
 955                 dsl_dataset_disown(drc->drc_real_ds, dmu_recv_tag);
 956         }
 957 }
 958
 959 /*
 960  * NB: callers *must* call dmu_recv_end() if this succeeds.
 961  */
 962 int
 963 dmu_recv_stream(dmu_recv_cookie_t *drc, vnode_t *vp, offset_t *voffp)
 964 {
 965         struct restorearg ra = { 0 };
 966         dmu_replay_record_t *drr;
 967         objset_t *os;
 968         zio_cksum_t pcksum;
 969
 970         if (drc->drc_drrb->drr_magic == BSWAP_64(DMU_BACKUP_MAGIC))
 971                 ra.byteswap = TRUE;
 972
 973         {
 974                 /* compute checksum of drr_begin record */
 975                 dmu_replay_record_t *drr;
 976                 drr = kmem_zalloc(sizeof (dmu_replay_record_t), KM_SLEEP);
 977
 978                 drr->drr_type = DRR_BEGIN;
 979                 drr->drr_u.drr_begin = *drc->drc_drrb;
 980                 if (ra.byteswap) {
 981                         fletcher_4_incremental_byteswap(drr,
 982                             sizeof (dmu_replay_record_t), &ra.cksum);
 983                 } else {
 984                         fletcher_4_incremental_native(drr,
 985                             sizeof (dmu_replay_record_t), &ra.cksum);
 986                 }
 987                 kmem_free(drr, sizeof (dmu_replay_record_t));
 988         }
 989
 990         if (ra.byteswap) {
 991                 struct drr_begin *drrb = drc->drc_drrb;
 992                 drrb->drr_magic = BSWAP_64(drrb->drr_magic);
 993                 drrb->drr_version = BSWAP_64(drrb->drr_version);
 994                 drrb->drr_creation_time = BSWAP_64(drrb->drr_creation_time);
 995                 drrb->drr_type = BSWAP_32(drrb->drr_type);
 996                 drrb->drr_toguid = BSWAP_64(drrb->drr_toguid);
 997                 drrb->drr_fromguid = BSWAP_64(drrb->drr_fromguid);
 998         }
 999
1000         ra.vp = vp;
1001         ra.voff = *voffp;
1002         ra.bufsize = 1<<20;
1003         ra.buf = kmem_alloc(ra.bufsize, KM_SLEEP);
1004
1005         /* these were verified in dmu_recv_begin */
1006         ASSERT(drc->drc_drrb->drr_version == DMU_BACKUP_STREAM_VERSION);
1007         ASSERT(drc->drc_drrb->drr_type < DMU_OST_NUMTYPES);
1008
1009         /*
1010          * Open the objset we are modifying.
1011          */
1012         VERIFY(dmu_objset_open_ds(drc->drc_real_ds, DMU_OST_ANY, &os) == 0);
1013
1014         ASSERT(drc->drc_real_ds->ds_phys->ds_flags & DS_FLAG_INCONSISTENT);
1015
1016         /*
1017          * Read records and process them.
1018          */
1019         pcksum = ra.cksum;
1020         while (ra.err == 0 &&
1021             NULL != (drr = restore_read(&ra, sizeof (*drr)))) {
1022                 if (issig(JUSTLOOKING) && issig(FORREAL)) {
1023                         ra.err = EINTR;
1024                         goto out;
1025                 }
1026
1027                 if (ra.byteswap)
1028                         backup_byteswap(drr);
1029
1030                 switch (drr->drr_type) {
1031                 case DRR_OBJECT:
1032                 {
1033                         /*
1034                          * We need to make a copy of the record header,
1035                          * because restore_{object,write} may need to
1036                          * restore_read(), which will invalidate drr.
1037                          */
1038                         struct drr_object drro = drr->drr_u.drr_object;
1039                         ra.err = restore_object(&ra, os, &drro);
1040                         break;
1041                 }
1042                 case DRR_FREEOBJECTS:
1043                 {
1044                         struct drr_freeobjects drrfo =
1045                             drr->drr_u.drr_freeobjects;
1046                         ra.err = restore_freeobjects(&ra, os, &drrfo);
1047                         break;
1048                 }
1049                 case DRR_WRITE:
1050                 {
1051                         struct drr_write drrw = drr->drr_u.drr_write;
1052                         ra.err = restore_write(&ra, os, &drrw);
1053                         break;
1054                 }
1055                 case DRR_FREE:
1056                 {
1057                         struct drr_free drrf = drr->drr_u.drr_free;
1058                         ra.err = restore_free(&ra, os, &drrf);
1059                         break;
1060                 }
1061                 case DRR_END:
1062                 {
1063                         struct drr_end drre = drr->drr_u.drr_end;
1064                         /*
1065                          * We compare against the *previous* checksum
1066                          * value, because the stored checksum is of
1067                          * everything before the DRR_END record.
1068                          */
1069                         if (!ZIO_CHECKSUM_EQUAL(drre.drr_checksum, pcksum))
1070                                 ra.err = ECKSUM;
1071                         goto out;
1072                 }
1073                 default:
1074                         ra.err = EINVAL;
1075                         goto out;
1076                 }
1077                 pcksum = ra.cksum;
1078         }
1079         ASSERT(ra.err != 0);
1080
1081 out:
1082         dmu_objset_close(os);
1083
1084         if (ra.err != 0) {
1085                 /*
1086                  * rollback or destroy what we created, so we don't
1087                  * leave it in the restoring state.
1088                  */
1089                 txg_wait_synced(drc->drc_real_ds->ds_dir->dd_pool, 0);
1090                 dmu_recv_abort_cleanup(drc);
1091         }
1092
1093         kmem_free(ra.buf, ra.bufsize);
1094         *voffp = ra.voff;
1095         return (ra.err);
1096 }
1097
1098 struct recvendsyncarg {
1099         char *tosnap;
1100         uint64_t creation_time;
1101         uint64_t toguid;
1102 };
1103
1104 static int
1105 recv_end_check(void *arg1, void *arg2, dmu_tx_t *tx)
1106 {
1107         dsl_dataset_t *ds = arg1;
1108         struct recvendsyncarg *resa = arg2;
1109
1110         return (dsl_dataset_snapshot_check(ds, resa->tosnap, tx));
1111 }
1112
1113 static void
1114 recv_end_sync(void *arg1, void *arg2, cred_t *cr, dmu_tx_t *tx)
1115 {
1116         dsl_dataset_t *ds = arg1;
1117         struct recvendsyncarg *resa = arg2;
1118
1119         dsl_dataset_snapshot_sync(ds, resa->tosnap, cr, tx);
1120
1121         /* set snapshot's creation time and guid */
1122         dmu_buf_will_dirty(ds->ds_prev->ds_dbuf, tx);
1123         ds->ds_prev->ds_phys->ds_creation_time = resa->creation_time;
1124         ds->ds_prev->ds_phys->ds_guid = resa->toguid;
1125         ds->ds_prev->ds_phys->ds_flags &= ~DS_FLAG_INCONSISTENT;
1126
1127         dmu_buf_will_dirty(ds->ds_dbuf, tx);
1128         ds->ds_phys->ds_flags &= ~DS_FLAG_INCONSISTENT;
1129 }
1130
1131 int
1132 dmu_recv_end(dmu_recv_cookie_t *drc)
1133 {
1134         struct recvendsyncarg resa;
1135         dsl_dataset_t *ds = drc->drc_logical_ds;
1136         int err;
1137
1138         /*
1139          * XXX hack; seems the ds is still dirty and
1140          * dsl_pool_zil_clean() expects it to have a ds_user_ptr
1141          * (and zil), but clone_swap() can close it.
1142          */
1143         txg_wait_synced(ds->ds_dir->dd_pool, 0);
1144
1145         if (ds != drc->drc_real_ds) {
1146                 /* we are doing an online recv */
1147                 if (dsl_dataset_tryown(ds, FALSE, dmu_recv_tag)) {
1148                         err = dsl_dataset_clone_swap(drc->drc_real_ds, ds,
1149                             drc->drc_force);
1150                         if (err)
1151                                 dsl_dataset_disown(ds, dmu_recv_tag);
1152                 } else {
1153                         err = EBUSY;
1154                         dsl_dataset_rele(ds, dmu_recv_tag);
1155                 }
1156                 /* dsl_dataset_destroy() will disown the ds */
1157                 (void) dsl_dataset_destroy(drc->drc_real_ds, dmu_recv_tag);
1158                 if (err)
1159                         return (err);
1160         }
1161
1162         resa.creation_time = drc->drc_drrb->drr_creation_time;
1163         resa.toguid = drc->drc_drrb->drr_toguid;
1164         resa.tosnap = drc->drc_tosnap;
1165
1166         err = dsl_sync_task_do(ds->ds_dir->dd_pool,
1167             recv_end_check, recv_end_sync, ds, &resa, 3);
1168         if (err) {
1169                 if (drc->drc_newfs) {
1170                         ASSERT(ds == drc->drc_real_ds);
1171                         (void) dsl_dataset_destroy(ds, dmu_recv_tag);
1172                         return (err);
1173                 } else {
1174                         (void) dsl_dataset_rollback(ds, DMU_OST_NONE);
1175                 }
1176         }
1177
1178         /* release the hold from dmu_recv_begin */
1179         dsl_dataset_disown(ds, dmu_recv_tag);
1180         return (err);
1181 }