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 2011 Nexenta Systems, Inc. All rights reserved.
  24  * Copyright (c) 2012 by Delphix. All rights reserved.
  25  * Copyright (c) 2012, Joyent, Inc. All rights reserved.
  26  */
  27 
  28 #include <sys/dmu.h>
  29 #include <sys/dmu_impl.h>
  30 #include <sys/dmu_tx.h>
  31 #include <sys/dbuf.h>
  32 #include <sys/dnode.h>
  33 #include <sys/zfs_context.h>
  34 #include <sys/dmu_objset.h>
  35 #include <sys/dmu_traverse.h>
  36 #include <sys/dsl_dataset.h>
  37 #include <sys/dsl_dir.h>
  38 #include <sys/dsl_prop.h>
  39 #include <sys/dsl_pool.h>
  40 #include <sys/dsl_synctask.h>
  41 #include <sys/zfs_ioctl.h>
  42 #include <sys/zap.h>
  43 #include <sys/zio_checksum.h>
  44 #include <sys/zfs_znode.h>
  45 #include <zfs_fletcher.h>
  46 #include <sys/avl.h>
  47 #include <sys/ddt.h>
  48 #include <sys/zfs_onexit.h>
  49 
  50 /* Set this tunable to TRUE to replace corrupt data with 0x2f5baddb10c */
  51 int zfs_send_corrupt_data = B_FALSE;
  52 
  53 static char *dmu_recv_tag = "dmu_recv_tag";
  54 char *tmp_dmu_recv_tag = "tmp_dmu_recv_tag";
  55 
  56 static int
  57 dump_bytes(dmu_sendarg_t *dsp, void *buf, int len)
  58 {
  59         dsl_dataset_t *ds = dsp->dsa_os->os_dsl_dataset;
  60         ssize_t resid; /* have to get resid to get detailed errno */
  61         ASSERT0(len % 8);
  62 
  63         fletcher_4_incremental_native(buf, len, &dsp->dsa_zc);
  64         dsp->dsa_err = vn_rdwr(UIO_WRITE, dsp->dsa_vp,
  65             (caddr_t)buf, len,
  66             0, UIO_SYSSPACE, FAPPEND, RLIM64_INFINITY, CRED(), &resid);
  67 
  68         mutex_enter(&ds->ds_sendstream_lock);
  69         *dsp->dsa_off += len;
  70         mutex_exit(&ds->ds_sendstream_lock);
  71 
  72         return (dsp->dsa_err);
  73 }
  74 
  75 static int
  76 dump_free(dmu_sendarg_t *dsp, uint64_t object, uint64_t offset,
  77     uint64_t length)
  78 {
  79         struct drr_free *drrf = &(dsp->dsa_drr->drr_u.drr_free);
  80 
  81         if (length != -1ULL && offset + length < offset)
  82                 length = -1ULL;
  83 
  84         /*
  85          * If there is a pending op, but it's not PENDING_FREE, push it out,
  86          * since free block aggregation can only be done for blocks of the
  87          * same type (i.e., DRR_FREE records can only be aggregated with
  88          * other DRR_FREE records.  DRR_FREEOBJECTS records can only be
  89          * aggregated with other DRR_FREEOBJECTS records.
  90          */
  91         if (dsp->dsa_pending_op != PENDING_NONE &&
  92             dsp->dsa_pending_op != PENDING_FREE) {
  93                 if (dump_bytes(dsp, dsp->dsa_drr,
  94                     sizeof (dmu_replay_record_t)) != 0)
  95                         return (EINTR);
  96                 dsp->dsa_pending_op = PENDING_NONE;
  97         }
  98 
  99         if (dsp->dsa_pending_op == PENDING_FREE) {
 100                 /*
 101                  * There should never be a PENDING_FREE if length is -1
 102                  * (because dump_dnode is the only place where this
 103                  * function is called with a -1, and only after flushing
 104                  * any pending record).
 105                  */
 106                 ASSERT(length != -1ULL);
 107                 /*
 108                  * Check to see whether this free block can be aggregated
 109                  * with pending one.
 110                  */
 111                 if (drrf->drr_object == object && drrf->drr_offset +
 112                     drrf->drr_length == offset) {
 113                         drrf->drr_length += length;
 114                         return (0);
 115                 } else {
 116                         /* not a continuation.  Push out pending record */
 117                         if (dump_bytes(dsp, dsp->dsa_drr,
 118                             sizeof (dmu_replay_record_t)) != 0)
 119                                 return (EINTR);
 120                         dsp->dsa_pending_op = PENDING_NONE;
 121                 }
 122         }
 123         /* create a FREE record and make it pending */
 124         bzero(dsp->dsa_drr, sizeof (dmu_replay_record_t));
 125         dsp->dsa_drr->drr_type = DRR_FREE;
 126         drrf->drr_object = object;
 127         drrf->drr_offset = offset;
 128         drrf->drr_length = length;
 129         drrf->drr_toguid = dsp->dsa_toguid;
 130         if (length == -1ULL) {
 131                 if (dump_bytes(dsp, dsp->dsa_drr,
 132                     sizeof (dmu_replay_record_t)) != 0)
 133                         return (EINTR);
 134         } else {
 135                 dsp->dsa_pending_op = PENDING_FREE;
 136         }
 137 
 138         return (0);
 139 }
 140 
 141 static int
 142 dump_data(dmu_sendarg_t *dsp, dmu_object_type_t type,
 143     uint64_t object, uint64_t offset, int blksz, const blkptr_t *bp, void *data)
 144 {
 145         struct drr_write *drrw = &(dsp->dsa_drr->drr_u.drr_write);
 146 
 147 
 148         /*
 149          * If there is any kind of pending aggregation (currently either
 150          * a grouping of free objects or free blocks), push it out to
 151          * the stream, since aggregation can't be done across operations
 152          * of different types.
 153          */
 154         if (dsp->dsa_pending_op != PENDING_NONE) {
 155                 if (dump_bytes(dsp, dsp->dsa_drr,
 156                     sizeof (dmu_replay_record_t)) != 0)
 157                         return (EINTR);
 158                 dsp->dsa_pending_op = PENDING_NONE;
 159         }
 160         /* write a DATA record */
 161         bzero(dsp->dsa_drr, sizeof (dmu_replay_record_t));
 162         dsp->dsa_drr->drr_type = DRR_WRITE;
 163         drrw->drr_object = object;
 164         drrw->drr_type = type;
 165         drrw->drr_offset = offset;
 166         drrw->drr_length = blksz;
 167         drrw->drr_toguid = dsp->dsa_toguid;
 168         drrw->drr_checksumtype = BP_GET_CHECKSUM(bp);
 169         if (zio_checksum_table[drrw->drr_checksumtype].ci_dedup)
 170                 drrw->drr_checksumflags |= DRR_CHECKSUM_DEDUP;
 171         DDK_SET_LSIZE(&drrw->drr_key, BP_GET_LSIZE(bp));
 172         DDK_SET_PSIZE(&drrw->drr_key, BP_GET_PSIZE(bp));
 173         DDK_SET_COMPRESS(&drrw->drr_key, BP_GET_COMPRESS(bp));
 174         drrw->drr_key.ddk_cksum = bp->blk_cksum;
 175 
 176         if (dump_bytes(dsp, dsp->dsa_drr, sizeof (dmu_replay_record_t)) != 0)
 177                 return (EINTR);
 178         if (dump_bytes(dsp, data, blksz) != 0)
 179                 return (EINTR);
 180         return (0);
 181 }
 182 
 183 static int
 184 dump_spill(dmu_sendarg_t *dsp, uint64_t object, int blksz, void *data)
 185 {
 186         struct drr_spill *drrs = &(dsp->dsa_drr->drr_u.drr_spill);
 187 
 188         if (dsp->dsa_pending_op != PENDING_NONE) {
 189                 if (dump_bytes(dsp, dsp->dsa_drr,
 190                     sizeof (dmu_replay_record_t)) != 0)
 191                         return (EINTR);
 192                 dsp->dsa_pending_op = PENDING_NONE;
 193         }
 194 
 195         /* write a SPILL record */
 196         bzero(dsp->dsa_drr, sizeof (dmu_replay_record_t));
 197         dsp->dsa_drr->drr_type = DRR_SPILL;
 198         drrs->drr_object = object;
 199         drrs->drr_length = blksz;
 200         drrs->drr_toguid = dsp->dsa_toguid;
 201 
 202         if (dump_bytes(dsp, dsp->dsa_drr, sizeof (dmu_replay_record_t)))
 203                 return (EINTR);
 204         if (dump_bytes(dsp, data, blksz))
 205                 return (EINTR);
 206         return (0);
 207 }
 208 
 209 static int
 210 dump_freeobjects(dmu_sendarg_t *dsp, uint64_t firstobj, uint64_t numobjs)
 211 {
 212         struct drr_freeobjects *drrfo = &(dsp->dsa_drr->drr_u.drr_freeobjects);
 213 
 214         /*
 215          * If there is a pending op, but it's not PENDING_FREEOBJECTS,
 216          * push it out, since free block aggregation can only be done for
 217          * blocks of the same type (i.e., DRR_FREE records can only be
 218          * aggregated with other DRR_FREE records.  DRR_FREEOBJECTS records
 219          * can only be aggregated with other DRR_FREEOBJECTS records.
 220          */
 221         if (dsp->dsa_pending_op != PENDING_NONE &&
 222             dsp->dsa_pending_op != PENDING_FREEOBJECTS) {
 223                 if (dump_bytes(dsp, dsp->dsa_drr,
 224                     sizeof (dmu_replay_record_t)) != 0)
 225                         return (EINTR);
 226                 dsp->dsa_pending_op = PENDING_NONE;
 227         }
 228         if (dsp->dsa_pending_op == PENDING_FREEOBJECTS) {
 229                 /*
 230                  * See whether this free object array can be aggregated
 231                  * with pending one
 232                  */
 233                 if (drrfo->drr_firstobj + drrfo->drr_numobjs == firstobj) {
 234                         drrfo->drr_numobjs += numobjs;
 235                         return (0);
 236                 } else {
 237                         /* can't be aggregated.  Push out pending record */
 238                         if (dump_bytes(dsp, dsp->dsa_drr,
 239                             sizeof (dmu_replay_record_t)) != 0)
 240                                 return (EINTR);
 241                         dsp->dsa_pending_op = PENDING_NONE;
 242                 }
 243         }
 244 
 245         /* write a FREEOBJECTS record */
 246         bzero(dsp->dsa_drr, sizeof (dmu_replay_record_t));
 247         dsp->dsa_drr->drr_type = DRR_FREEOBJECTS;
 248         drrfo->drr_firstobj = firstobj;
 249         drrfo->drr_numobjs = numobjs;
 250         drrfo->drr_toguid = dsp->dsa_toguid;
 251 
 252         dsp->dsa_pending_op = PENDING_FREEOBJECTS;
 253 
 254         return (0);
 255 }
 256 
 257 static int
 258 dump_dnode(dmu_sendarg_t *dsp, uint64_t object, dnode_phys_t *dnp)
 259 {
 260         struct drr_object *drro = &(dsp->dsa_drr->drr_u.drr_object);
 261 
 262         if (dnp == NULL || dnp->dn_type == DMU_OT_NONE)
 263                 return (dump_freeobjects(dsp, object, 1));
 264 
 265         if (dsp->dsa_pending_op != PENDING_NONE) {
 266                 if (dump_bytes(dsp, dsp->dsa_drr,
 267                     sizeof (dmu_replay_record_t)) != 0)
 268                         return (EINTR);
 269                 dsp->dsa_pending_op = PENDING_NONE;
 270         }
 271 
 272         /* write an OBJECT record */
 273         bzero(dsp->dsa_drr, sizeof (dmu_replay_record_t));
 274         dsp->dsa_drr->drr_type = DRR_OBJECT;
 275         drro->drr_object = object;
 276         drro->drr_type = dnp->dn_type;
 277         drro->drr_bonustype = dnp->dn_bonustype;
 278         drro->drr_blksz = dnp->dn_datablkszsec << SPA_MINBLOCKSHIFT;
 279         drro->drr_bonuslen = dnp->dn_bonuslen;
 280         drro->drr_checksumtype = dnp->dn_checksum;
 281         drro->drr_compress = dnp->dn_compress;
 282         drro->drr_toguid = dsp->dsa_toguid;
 283 
 284         if (dump_bytes(dsp, dsp->dsa_drr, sizeof (dmu_replay_record_t)) != 0)
 285                 return (EINTR);
 286 
 287         if (dump_bytes(dsp, DN_BONUS(dnp), P2ROUNDUP(dnp->dn_bonuslen, 8)) != 0)
 288                 return (EINTR);
 289 
 290         /* free anything past the end of the file */
 291         if (dump_free(dsp, object, (dnp->dn_maxblkid + 1) *
 292             (dnp->dn_datablkszsec << SPA_MINBLOCKSHIFT), -1ULL))
 293                 return (EINTR);
 294         if (dsp->dsa_err)
 295                 return (EINTR);
 296         return (0);
 297 }
 298 
 299 #define BP_SPAN(dnp, level) \
 300         (((uint64_t)dnp->dn_datablkszsec) << (SPA_MINBLOCKSHIFT + \
 301         (level) * (dnp->dn_indblkshift - SPA_BLKPTRSHIFT)))
 302 
 303 /* ARGSUSED */
 304 static int
 305 backup_cb(spa_t *spa, zilog_t *zilog, const blkptr_t *bp, arc_buf_t *pbuf,
 306     const zbookmark_t *zb, const dnode_phys_t *dnp, void *arg)
 307 {
 308         dmu_sendarg_t *dsp = arg;
 309         dmu_object_type_t type = bp ? BP_GET_TYPE(bp) : DMU_OT_NONE;
 310         int err = 0;
 311 
 312         if (issig(JUSTLOOKING) && issig(FORREAL))
 313                 return (EINTR);
 314 
 315         if (zb->zb_object != DMU_META_DNODE_OBJECT &&
 316             DMU_OBJECT_IS_SPECIAL(zb->zb_object)) {
 317                 return (0);
 318         } else if (bp == NULL && zb->zb_object == DMU_META_DNODE_OBJECT) {
 319                 uint64_t span = BP_SPAN(dnp, zb->zb_level);
 320                 uint64_t dnobj = (zb->zb_blkid * span) >> DNODE_SHIFT;
 321                 err = dump_freeobjects(dsp, dnobj, span >> DNODE_SHIFT);
 322         } else if (bp == NULL) {
 323                 uint64_t span = BP_SPAN(dnp, zb->zb_level);
 324                 err = dump_free(dsp, zb->zb_object, zb->zb_blkid * span, span);
 325         } else if (zb->zb_level > 0 || type == DMU_OT_OBJSET) {
 326                 return (0);
 327         } else if (type == DMU_OT_DNODE) {
 328                 dnode_phys_t *blk;
 329                 int i;
 330                 int blksz = BP_GET_LSIZE(bp);
 331                 uint32_t aflags = ARC_WAIT;
 332                 arc_buf_t *abuf;
 333 
 334                 if (dsl_read(NULL, spa, bp, pbuf,
 335                     arc_getbuf_func, &abuf, ZIO_PRIORITY_ASYNC_READ,
 336                     ZIO_FLAG_CANFAIL, &aflags, zb) != 0)
 337                         return (EIO);
 338 
 339                 blk = abuf->b_data;
 340                 for (i = 0; i < blksz >> DNODE_SHIFT; i++) {
 341                         uint64_t dnobj = (zb->zb_blkid <<
 342                             (DNODE_BLOCK_SHIFT - DNODE_SHIFT)) + i;
 343                         err = dump_dnode(dsp, dnobj, blk+i);
 344                         if (err)
 345                                 break;
 346                 }
 347                 (void) arc_buf_remove_ref(abuf, &abuf);
 348         } else if (type == DMU_OT_SA) {
 349                 uint32_t aflags = ARC_WAIT;
 350                 arc_buf_t *abuf;
 351                 int blksz = BP_GET_LSIZE(bp);
 352 
 353                 if (arc_read_nolock(NULL, spa, bp,
 354                     arc_getbuf_func, &abuf, ZIO_PRIORITY_ASYNC_READ,
 355                     ZIO_FLAG_CANFAIL, &aflags, zb) != 0)
 356                         return (EIO);
 357 
 358                 err = dump_spill(dsp, zb->zb_object, blksz, abuf->b_data);
 359                 (void) arc_buf_remove_ref(abuf, &abuf);
 360         } else { /* it's a level-0 block of a regular object */
 361                 uint32_t aflags = ARC_WAIT;
 362                 arc_buf_t *abuf;
 363                 int blksz = BP_GET_LSIZE(bp);
 364 
 365                 if (dsl_read(NULL, spa, bp, pbuf,
 366                     arc_getbuf_func, &abuf, ZIO_PRIORITY_ASYNC_READ,
 367                     ZIO_FLAG_CANFAIL, &aflags, zb) != 0) {
 368                         if (zfs_send_corrupt_data) {
 369                                 /* Send a block filled with 0x"zfs badd bloc" */
 370                                 abuf = arc_buf_alloc(spa, blksz, &abuf,
 371                                     ARC_BUFC_DATA);
 372                                 uint64_t *ptr;
 373                                 for (ptr = abuf->b_data;
 374                                     (char *)ptr < (char *)abuf->b_data + blksz;
 375                                     ptr++)
 376                                         *ptr = 0x2f5baddb10c;
 377                         } else {
 378                                 return (EIO);
 379                         }
 380                 }
 381 
 382                 err = dump_data(dsp, type, zb->zb_object, zb->zb_blkid * blksz,
 383                     blksz, bp, abuf->b_data);
 384                 (void) arc_buf_remove_ref(abuf, &abuf);
 385         }
 386 
 387         ASSERT(err == 0 || err == EINTR);
 388         return (err);
 389 }
 390 
 391 /*
 392  * Return TRUE if 'earlier' is an earlier snapshot in 'later's timeline.
 393  * For example, they could both be snapshots of the same filesystem, and
 394  * 'earlier' is before 'later'.  Or 'earlier' could be the origin of
 395  * 'later's filesystem.  Or 'earlier' could be an older snapshot in the origin's
 396  * filesystem.  Or 'earlier' could be the origin's origin.
 397  */
 398 static boolean_t
 399 is_before(dsl_dataset_t *later, dsl_dataset_t *earlier)
 400 {
 401         dsl_pool_t *dp = later->ds_dir->dd_pool;
 402         int error;
 403         boolean_t ret;
 404         dsl_dataset_t *origin;
 405 
 406         if (earlier->ds_phys->ds_creation_txg >=
 407             later->ds_phys->ds_creation_txg)
 408                 return (B_FALSE);
 409 
 410         if (later->ds_dir == earlier->ds_dir)
 411                 return (B_TRUE);
 412         if (!dsl_dir_is_clone(later->ds_dir))
 413                 return (B_FALSE);
 414 
 415         rw_enter(&dp->dp_config_rwlock, RW_READER);
 416         if (later->ds_dir->dd_phys->dd_origin_obj == earlier->ds_object) {
 417                 rw_exit(&dp->dp_config_rwlock);
 418                 return (B_TRUE);
 419         }
 420         error = dsl_dataset_hold_obj(dp,
 421             later->ds_dir->dd_phys->dd_origin_obj, FTAG, &origin);
 422         rw_exit(&dp->dp_config_rwlock);
 423         if (error != 0)
 424                 return (B_FALSE);
 425         ret = is_before(origin, earlier);
 426         dsl_dataset_rele(origin, FTAG);
 427         return (ret);
 428 }
 429 
 430 int
 431 dmu_send(objset_t *tosnap, objset_t *fromsnap, int outfd, vnode_t *vp,
 432     offset_t *off)
 433 {
 434         dsl_dataset_t *ds = tosnap->os_dsl_dataset;
 435         dsl_dataset_t *fromds = fromsnap ? fromsnap->os_dsl_dataset : NULL;
 436         dmu_replay_record_t *drr;
 437         dmu_sendarg_t *dsp;
 438         int err;
 439         uint64_t fromtxg = 0;
 440 
 441         /* tosnap must be a snapshot */
 442         if (ds->ds_phys->ds_next_snap_obj == 0)
 443                 return (EINVAL);
 444 
 445         /*
 446          * fromsnap must be an earlier snapshot from the same fs as tosnap,
 447          * or the origin's fs.
 448          */
 449         if (fromds != NULL && !is_before(ds, fromds))
 450                 return (EXDEV);
 451 
 452         drr = kmem_zalloc(sizeof (dmu_replay_record_t), KM_SLEEP);
 453         drr->drr_type = DRR_BEGIN;
 454         drr->drr_u.drr_begin.drr_magic = DMU_BACKUP_MAGIC;
 455         DMU_SET_STREAM_HDRTYPE(drr->drr_u.drr_begin.drr_versioninfo,
 456             DMU_SUBSTREAM);
 457 
 458 #ifdef _KERNEL
 459         if (dmu_objset_type(tosnap) == DMU_OST_ZFS) {
 460                 uint64_t version;
 461                 if (zfs_get_zplprop(tosnap, ZFS_PROP_VERSION, &version) != 0) {
 462                         kmem_free(drr, sizeof (dmu_replay_record_t));
 463                         return (EINVAL);
 464                 }
 465                 if (version == ZPL_VERSION_SA) {
 466                         DMU_SET_FEATUREFLAGS(
 467                             drr->drr_u.drr_begin.drr_versioninfo,
 468                             DMU_BACKUP_FEATURE_SA_SPILL);
 469                 }
 470         }
 471 #endif
 472 
 473         drr->drr_u.drr_begin.drr_creation_time =
 474             ds->ds_phys->ds_creation_time;
 475         drr->drr_u.drr_begin.drr_type = tosnap->os_phys->os_type;
 476         if (fromds != NULL && ds->ds_dir != fromds->ds_dir)
 477                 drr->drr_u.drr_begin.drr_flags |= DRR_FLAG_CLONE;
 478         drr->drr_u.drr_begin.drr_toguid = ds->ds_phys->ds_guid;
 479         if (ds->ds_phys->ds_flags & DS_FLAG_CI_DATASET)
 480                 drr->drr_u.drr_begin.drr_flags |= DRR_FLAG_CI_DATA;
 481 
 482         if (fromds)
 483                 drr->drr_u.drr_begin.drr_fromguid = fromds->ds_phys->ds_guid;
 484         dsl_dataset_name(ds, drr->drr_u.drr_begin.drr_toname);
 485 
 486         if (fromds)
 487                 fromtxg = fromds->ds_phys->ds_creation_txg;
 488 
 489         dsp = kmem_zalloc(sizeof (dmu_sendarg_t), KM_SLEEP);
 490 
 491         dsp->dsa_drr = drr;
 492         dsp->dsa_vp = vp;
 493         dsp->dsa_outfd = outfd;
 494         dsp->dsa_proc = curproc;
 495         dsp->dsa_os = tosnap;
 496         dsp->dsa_off = off;
 497         dsp->dsa_toguid = ds->ds_phys->ds_guid;
 498         ZIO_SET_CHECKSUM(&dsp->dsa_zc, 0, 0, 0, 0);
 499         dsp->dsa_pending_op = PENDING_NONE;
 500 
 501         mutex_enter(&ds->ds_sendstream_lock);
 502         list_insert_head(&ds->ds_sendstreams, dsp);
 503         mutex_exit(&ds->ds_sendstream_lock);
 504 
 505         if (dump_bytes(dsp, drr, sizeof (dmu_replay_record_t)) != 0) {
 506                 err = dsp->dsa_err;
 507                 goto out;
 508         }
 509 
 510         err = traverse_dataset(ds, fromtxg, TRAVERSE_PRE | TRAVERSE_PREFETCH,
 511             backup_cb, dsp);
 512 
 513         if (dsp->dsa_pending_op != PENDING_NONE)
 514                 if (dump_bytes(dsp, drr, sizeof (dmu_replay_record_t)) != 0)
 515                         err = EINTR;
 516 
 517         if (err) {
 518                 if (err == EINTR && dsp->dsa_err)
 519                         err = dsp->dsa_err;
 520                 goto out;
 521         }
 522 
 523         bzero(drr, sizeof (dmu_replay_record_t));
 524         drr->drr_type = DRR_END;
 525         drr->drr_u.drr_end.drr_checksum = dsp->dsa_zc;
 526         drr->drr_u.drr_end.drr_toguid = dsp->dsa_toguid;
 527 
 528         if (dump_bytes(dsp, drr, sizeof (dmu_replay_record_t)) != 0) {
 529                 err = dsp->dsa_err;
 530                 goto out;
 531         }
 532 
 533 out:
 534         mutex_enter(&ds->ds_sendstream_lock);
 535         list_remove(&ds->ds_sendstreams, dsp);
 536         mutex_exit(&ds->ds_sendstream_lock);
 537 
 538         kmem_free(drr, sizeof (dmu_replay_record_t));
 539         kmem_free(dsp, sizeof (dmu_sendarg_t));
 540 
 541         return (err);
 542 }
 543 
 544 int
 545 dmu_send_estimate(objset_t *tosnap, objset_t *fromsnap, uint64_t *sizep)
 546 {
 547         dsl_dataset_t *ds = tosnap->os_dsl_dataset;
 548         dsl_dataset_t *fromds = fromsnap ? fromsnap->os_dsl_dataset : NULL;
 549         dsl_pool_t *dp = ds->ds_dir->dd_pool;
 550         int err;
 551         uint64_t size;
 552 
 553         /* tosnap must be a snapshot */
 554         if (ds->ds_phys->ds_next_snap_obj == 0)
 555                 return (EINVAL);
 556 
 557         /*
 558          * fromsnap must be an earlier snapshot from the same fs as tosnap,
 559          * or the origin's fs.
 560          */
 561         if (fromds != NULL && !is_before(ds, fromds))
 562                 return (EXDEV);
 563 
 564         /* Get uncompressed size estimate of changed data. */
 565         if (fromds == NULL) {
 566                 size = ds->ds_phys->ds_uncompressed_bytes;
 567         } else {
 568                 uint64_t used, comp;
 569                 err = dsl_dataset_space_written(fromds, ds,
 570                     &used, &comp, &size);
 571                 if (err)
 572                         return (err);
 573         }
 574 
 575         /*
 576          * Assume that space (both on-disk and in-stream) is dominated by
 577          * data.  We will adjust for indirect blocks and the copies property,
 578          * but ignore per-object space used (eg, dnodes and DRR_OBJECT records).
 579          */
 580 
 581         /*
 582          * Subtract out approximate space used by indirect blocks.
 583          * Assume most space is used by data blocks (non-indirect, non-dnode).
 584          * Assume all blocks are recordsize.  Assume ditto blocks and
 585          * internal fragmentation counter out compression.
 586          *
 587          * Therefore, space used by indirect blocks is sizeof(blkptr_t) per
 588          * block, which we observe in practice.
 589          */
 590         uint64_t recordsize;
 591         rw_enter(&dp->dp_config_rwlock, RW_READER);
 592         err = dsl_prop_get_ds(ds, "recordsize",
 593             sizeof (recordsize), 1, &recordsize, NULL);
 594         rw_exit(&dp->dp_config_rwlock);
 595         if (err)
 596                 return (err);
 597         size -= size / recordsize * sizeof (blkptr_t);
 598 
 599         /* Add in the space for the record associated with each block. */
 600         size += size / recordsize * sizeof (dmu_replay_record_t);
 601 
 602         *sizep = size;
 603 
 604         return (0);
 605 }
 606 
 607 struct recvbeginsyncarg {
 608         const char *tofs;
 609         const char *tosnap;
 610         dsl_dataset_t *origin;
 611         uint64_t fromguid;
 612         dmu_objset_type_t type;
 613         void *tag;
 614         boolean_t force;
 615         uint64_t dsflags;
 616         char clonelastname[MAXNAMELEN];
 617         dsl_dataset_t *ds; /* the ds to recv into; returned from the syncfunc */
 618         cred_t *cr;
 619 };
 620 
 621 /* ARGSUSED */
 622 static int
 623 recv_new_check(void *arg1, void *arg2, dmu_tx_t *tx)
 624 {
 625         dsl_dir_t *dd = arg1;
 626         struct recvbeginsyncarg *rbsa = arg2;
 627         objset_t *mos = dd->dd_pool->dp_meta_objset;
 628         uint64_t val;
 629         int err;
 630 
 631         err = zap_lookup(mos, dd->dd_phys->dd_child_dir_zapobj,
 632             strrchr(rbsa->tofs, '/') + 1, sizeof (uint64_t), 1, &val);
 633 
 634         if (err != ENOENT)
 635                 return (err ? err : EEXIST);
 636 
 637         if (rbsa->origin) {
 638                 /* make sure it's a snap in the same pool */
 639                 if (rbsa->origin->ds_dir->dd_pool != dd->dd_pool)
 640                         return (EXDEV);
 641                 if (!dsl_dataset_is_snapshot(rbsa->origin))
 642                         return (EINVAL);
 643                 if (rbsa->origin->ds_phys->ds_guid != rbsa->fromguid)
 644                         return (ENODEV);
 645         }
 646 
 647         /*
 648          * Check dataset and snapshot quotas before receiving. We'll recheck
 649          * again at the end, but might as well abort before receiving if we're
 650          * already over quota.
 651          */
 652         if (dd->dd_parent != NULL) {
 653                 err = dsl_dir_dscount_check(dd->dd_parent, NULL, 1, NULL);
 654                 if (err != 0)
 655                         return (err);
 656         }
 657 
 658         err = dsl_snapcount_check(dd, tx, 1, NULL);
 659         if (err != 0)
 660                 return (err);
 661 
 662 
 663         return (0);
 664 }
 665 
 666 static void
 667 recv_new_sync(void *arg1, void *arg2, dmu_tx_t *tx)
 668 {
 669         dsl_dir_t *dd = arg1;
 670         struct recvbeginsyncarg *rbsa = arg2;
 671         uint64_t flags = DS_FLAG_INCONSISTENT | rbsa->dsflags;
 672         uint64_t dsobj;
 673 
 674         /* Create and open new dataset. */
 675         dsobj = dsl_dataset_create_sync(dd, strrchr(rbsa->tofs, '/') + 1,
 676             rbsa->origin, flags, rbsa->cr, tx);
 677         VERIFY(0 == dsl_dataset_own_obj(dd->dd_pool, dsobj,
 678             B_TRUE, dmu_recv_tag, &rbsa->ds));
 679 
 680         if (rbsa->origin == NULL) {
 681                 (void) dmu_objset_create_impl(dd->dd_pool->dp_spa,
 682                     rbsa->ds, &rbsa->ds->ds_phys->ds_bp, rbsa->type, tx);
 683         }
 684 
 685         spa_history_log_internal_ds(rbsa->ds, "receive new", tx, "");
 686 }
 687 
 688 /* ARGSUSED */
 689 static int
 690 recv_existing_check(void *arg1, void *arg2, dmu_tx_t *tx)
 691 {
 692         dsl_dataset_t *ds = arg1;
 693         struct recvbeginsyncarg *rbsa = arg2;
 694         int err;
 695         uint64_t val;
 696 
 697         /* must not have any changes since most recent snapshot */
 698         if (!rbsa->force && dsl_dataset_modified_since_lastsnap(ds))
 699                 return (ETXTBSY);
 700 
 701         /* new snapshot name must not exist */
 702         err = zap_lookup(ds->ds_dir->dd_pool->dp_meta_objset,
 703             ds->ds_phys->ds_snapnames_zapobj, rbsa->tosnap, 8, 1, &val);
 704         if (err == 0)
 705                 return (EEXIST);
 706         if (err != ENOENT)
 707                 return (err);
 708 
 709         if (rbsa->fromguid) {
 710                 /* if incremental, most recent snapshot must match fromguid */
 711                 if (ds->ds_prev == NULL)
 712                         return (ENODEV);
 713 
 714                 /*
 715                  * most recent snapshot must match fromguid, or there are no
 716                  * changes since the fromguid one
 717                  */
 718                 if (ds->ds_prev->ds_phys->ds_guid != rbsa->fromguid) {
 719                         uint64_t birth = ds->ds_prev->ds_phys->ds_bp.blk_birth;
 720                         uint64_t obj = ds->ds_prev->ds_phys->ds_prev_snap_obj;
 721                         while (obj != 0) {
 722                                 dsl_dataset_t *snap;
 723                                 err = dsl_dataset_hold_obj(ds->ds_dir->dd_pool,
 724                                     obj, FTAG, &snap);
 725                                 if (err)
 726                                         return (ENODEV);
 727                                 if (snap->ds_phys->ds_creation_txg < birth) {
 728                                         dsl_dataset_rele(snap, FTAG);
 729                                         return (ENODEV);
 730                                 }
 731                                 if (snap->ds_phys->ds_guid == rbsa->fromguid) {
 732                                         dsl_dataset_rele(snap, FTAG);
 733                                         break; /* it's ok */
 734                                 }
 735                                 obj = snap->ds_phys->ds_prev_snap_obj;
 736                                 dsl_dataset_rele(snap, FTAG);
 737                         }
 738                         if (obj == 0)
 739                                 return (ENODEV);
 740                 }
 741         } else {
 742                 /* if full, most recent snapshot must be $ORIGIN */
 743                 if (ds->ds_phys->ds_prev_snap_txg >= TXG_INITIAL)
 744                         return (ENODEV);
 745 
 746                 /* Check snapshot quota before receiving */
 747                 err = dsl_snapcount_check(ds->ds_dir, tx, 1, NULL);
 748                 if (err != 0)
 749                         return (err);
 750         }
 751 
 752         /* temporary clone name must not exist */
 753         err = zap_lookup(ds->ds_dir->dd_pool->dp_meta_objset,
 754             ds->ds_dir->dd_phys->dd_child_dir_zapobj,
 755             rbsa->clonelastname, 8, 1, &val);
 756         if (err == 0)
 757                 return (EEXIST);
 758         if (err != ENOENT)
 759                 return (err);
 760 
 761         return (0);
 762 }
 763 
 764 /* ARGSUSED */
 765 static void
 766 recv_existing_sync(void *arg1, void *arg2, dmu_tx_t *tx)
 767 {
 768         dsl_dataset_t *ohds = arg1;
 769         struct recvbeginsyncarg *rbsa = arg2;
 770         dsl_pool_t *dp = ohds->ds_dir->dd_pool;
 771         dsl_dataset_t *cds;
 772         uint64_t flags = DS_FLAG_INCONSISTENT | rbsa->dsflags;
 773         uint64_t dsobj;
 774 
 775         /* create and open the temporary clone */
 776         dsobj = dsl_dataset_create_sync(ohds->ds_dir, rbsa->clonelastname,
 777             ohds->ds_prev, flags, rbsa->cr, tx);
 778         VERIFY(0 == dsl_dataset_own_obj(dp, dsobj, B_TRUE, dmu_recv_tag, &cds));
 779 
 780         /*
 781          * If we actually created a non-clone, we need to create the
 782          * objset in our new dataset.
 783          */
 784         if (BP_IS_HOLE(dsl_dataset_get_blkptr(cds))) {
 785                 (void) dmu_objset_create_impl(dp->dp_spa,
 786                     cds, dsl_dataset_get_blkptr(cds), rbsa->type, tx);
 787         }
 788 
 789         rbsa->ds = cds;
 790 
 791         spa_history_log_internal_ds(cds, "receive over existing", tx, "");
 792 }
 793 
 794 static boolean_t
 795 dmu_recv_verify_features(dsl_dataset_t *ds, struct drr_begin *drrb)
 796 {
 797         int featureflags;
 798 
 799         featureflags = DMU_GET_FEATUREFLAGS(drrb->drr_versioninfo);
 800 
 801         /* Verify pool version supports SA if SA_SPILL feature set */
 802         return ((featureflags & DMU_BACKUP_FEATURE_SA_SPILL) &&
 803             (spa_version(dsl_dataset_get_spa(ds)) < SPA_VERSION_SA));
 804 }
 805 
 806 /*
 807  * NB: callers *MUST* call dmu_recv_stream() if dmu_recv_begin()
 808  * succeeds; otherwise we will leak the holds on the datasets.
 809  */
 810 int
 811 dmu_recv_begin(char *tofs, char *tosnap, char *top_ds, struct drr_begin *drrb,
 812     boolean_t force, objset_t *origin, dmu_recv_cookie_t *drc)
 813 {
 814         int err = 0;
 815         boolean_t byteswap;
 816         struct recvbeginsyncarg rbsa = { 0 };
 817         uint64_t versioninfo;
 818         int flags;
 819         dsl_dataset_t *ds;
 820 
 821         if (drrb->drr_magic == DMU_BACKUP_MAGIC)
 822                 byteswap = FALSE;
 823         else if (drrb->drr_magic == BSWAP_64(DMU_BACKUP_MAGIC))
 824                 byteswap = TRUE;
 825         else
 826                 return (EINVAL);
 827 
 828         rbsa.tofs = tofs;
 829         rbsa.tosnap = tosnap;
 830         rbsa.origin = origin ? origin->os_dsl_dataset : NULL;
 831         rbsa.fromguid = drrb->drr_fromguid;
 832         rbsa.type = drrb->drr_type;
 833         rbsa.tag = FTAG;
 834         rbsa.dsflags = 0;
 835         rbsa.cr = CRED();
 836         versioninfo = drrb->drr_versioninfo;
 837         flags = drrb->drr_flags;
 838 
 839         if (byteswap) {
 840                 rbsa.type = BSWAP_32(rbsa.type);
 841                 rbsa.fromguid = BSWAP_64(rbsa.fromguid);
 842                 versioninfo = BSWAP_64(versioninfo);
 843                 flags = BSWAP_32(flags);
 844         }
 845 
 846         if (DMU_GET_STREAM_HDRTYPE(versioninfo) == DMU_COMPOUNDSTREAM ||
 847             rbsa.type >= DMU_OST_NUMTYPES ||
 848             ((flags & DRR_FLAG_CLONE) && origin == NULL))
 849                 return (EINVAL);
 850 
 851         if (flags & DRR_FLAG_CI_DATA)
 852                 rbsa.dsflags = DS_FLAG_CI_DATASET;
 853 
 854         bzero(drc, sizeof (dmu_recv_cookie_t));
 855         drc->drc_drrb = drrb;
 856         drc->drc_tosnap = tosnap;
 857         drc->drc_top_ds = top_ds;
 858         drc->drc_force = force;
 859 
 860         /*
 861          * Process the begin in syncing context.
 862          */
 863 
 864         /* open the dataset we are logically receiving into */
 865         err = dsl_dataset_hold(tofs, dmu_recv_tag, &ds);
 866         if (err == 0) {
 867                 if (dmu_recv_verify_features(ds, drrb)) {
 868                         dsl_dataset_rele(ds, dmu_recv_tag);
 869                         return (ENOTSUP);
 870                 }
 871                 /* target fs already exists; recv into temp clone */
 872 
 873                 /* Can't recv a clone into an existing fs */
 874                 if (flags & DRR_FLAG_CLONE) {
 875                         dsl_dataset_rele(ds, dmu_recv_tag);
 876                         return (EINVAL);
 877                 }
 878 
 879                 /* must not have an incremental recv already in progress */
 880                 if (!mutex_tryenter(&ds->ds_recvlock)) {
 881                         dsl_dataset_rele(ds, dmu_recv_tag);
 882                         return (EBUSY);
 883                 }
 884 
 885                 /* tmp clone name is: tofs/%tosnap" */
 886                 (void) snprintf(rbsa.clonelastname, sizeof (rbsa.clonelastname),
 887                     "%%%s", tosnap);
 888                 rbsa.force = force;
 889                 err = dsl_sync_task_do(ds->ds_dir->dd_pool,
 890                     recv_existing_check, recv_existing_sync, ds, &rbsa, 5);
 891                 if (err) {
 892                         mutex_exit(&ds->ds_recvlock);
 893                         dsl_dataset_rele(ds, dmu_recv_tag);
 894                         return (err);
 895                 }
 896                 drc->drc_logical_ds = ds;
 897                 drc->drc_real_ds = rbsa.ds;
 898         } else if (err == ENOENT) {
 899                 /* target fs does not exist; must be a full backup or clone */
 900                 char *cp;
 901 
 902                 /*
 903                  * If it's a non-clone incremental, we are missing the
 904                  * target fs, so fail the recv.
 905                  */
 906                 if (rbsa.fromguid && !(flags & DRR_FLAG_CLONE))
 907                         return (ENOENT);
 908 
 909                 /* Open the parent of tofs */
 910                 cp = strrchr(tofs, '/');
 911                 *cp = '\0';
 912                 err = dsl_dataset_hold(tofs, FTAG, &ds);
 913                 *cp = '/';
 914                 if (err)
 915                         return (err);
 916 
 917                 if (dmu_recv_verify_features(ds, drrb)) {
 918                         dsl_dataset_rele(ds, FTAG);
 919                         return (ENOTSUP);
 920                 }
 921 
 922                 err = dsl_sync_task_do(ds->ds_dir->dd_pool,
 923                     recv_new_check, recv_new_sync, ds->ds_dir, &rbsa, 5);
 924                 dsl_dataset_rele(ds, FTAG);
 925                 if (err)
 926                         return (err);
 927                 drc->drc_logical_ds = drc->drc_real_ds = rbsa.ds;
 928                 drc->drc_newfs = B_TRUE;
 929         }
 930 
 931         return (err);
 932 }
 933 
 934 struct restorearg {
 935         int err;
 936         int byteswap;
 937         vnode_t *vp;
 938         char *buf;
 939         uint64_t voff;
 940         int bufsize; /* amount of memory allocated for buf */
 941         zio_cksum_t cksum;
 942         avl_tree_t *guid_to_ds_map;
 943 };
 944 
 945 typedef struct guid_map_entry {
 946         uint64_t        guid;
 947         dsl_dataset_t   *gme_ds;
 948         avl_node_t      avlnode;
 949 } guid_map_entry_t;
 950 
 951 static int
 952 guid_compare(const void *arg1, const void *arg2)
 953 {
 954         const guid_map_entry_t *gmep1 = arg1;
 955         const guid_map_entry_t *gmep2 = arg2;
 956 
 957         if (gmep1->guid < gmep2->guid)
 958                 return (-1);
 959         else if (gmep1->guid > gmep2->guid)
 960                 return (1);
 961         return (0);
 962 }
 963 
 964 static void
 965 free_guid_map_onexit(void *arg)
 966 {
 967         avl_tree_t *ca = arg;
 968         void *cookie = NULL;
 969         guid_map_entry_t *gmep;
 970 
 971         while ((gmep = avl_destroy_nodes(ca, &cookie)) != NULL) {
 972                 dsl_dataset_rele(gmep->gme_ds, ca);
 973                 kmem_free(gmep, sizeof (guid_map_entry_t));
 974         }
 975         avl_destroy(ca);
 976         kmem_free(ca, sizeof (avl_tree_t));
 977 }
 978 
 979 static void *
 980 restore_read(struct restorearg *ra, int len)
 981 {
 982         void *rv;
 983         int done = 0;
 984 
 985         /* some things will require 8-byte alignment, so everything must */
 986         ASSERT0(len % 8);
 987 
 988         while (done < len) {
 989                 ssize_t resid;
 990 
 991                 ra->err = vn_rdwr(UIO_READ, ra->vp,
 992                     (caddr_t)ra->buf + done, len - done,
 993                     ra->voff, UIO_SYSSPACE, FAPPEND,
 994                     RLIM64_INFINITY, CRED(), &resid);
 995 
 996                 if (resid == len - done)
 997                         ra->err = EINVAL;
 998                 ra->voff += len - done - resid;
 999                 done = len - resid;
1000                 if (ra->err)
1001                         return (NULL);
1002         }
1003 
1004         ASSERT3U(done, ==, len);
1005         rv = ra->buf;
1006         if (ra->byteswap)
1007                 fletcher_4_incremental_byteswap(rv, len, &ra->cksum);
1008         else
1009                 fletcher_4_incremental_native(rv, len, &ra->cksum);
1010         return (rv);
1011 }
1012 
1013 static void
1014 backup_byteswap(dmu_replay_record_t *drr)
1015 {
1016 #define DO64(X) (drr->drr_u.X = BSWAP_64(drr->drr_u.X))
1017 #define DO32(X) (drr->drr_u.X = BSWAP_32(drr->drr_u.X))
1018         drr->drr_type = BSWAP_32(drr->drr_type);
1019         drr->drr_payloadlen = BSWAP_32(drr->drr_payloadlen);
1020         switch (drr->drr_type) {
1021         case DRR_BEGIN:
1022                 DO64(drr_begin.drr_magic);
1023                 DO64(drr_begin.drr_versioninfo);
1024                 DO64(drr_begin.drr_creation_time);
1025                 DO32(drr_begin.drr_type);
1026                 DO32(drr_begin.drr_flags);
1027                 DO64(drr_begin.drr_toguid);
1028                 DO64(drr_begin.drr_fromguid);
1029                 break;
1030         case DRR_OBJECT:
1031                 DO64(drr_object.drr_object);
1032                 /* DO64(drr_object.drr_allocation_txg); */
1033                 DO32(drr_object.drr_type);
1034                 DO32(drr_object.drr_bonustype);
1035                 DO32(drr_object.drr_blksz);
1036                 DO32(drr_object.drr_bonuslen);
1037                 DO64(drr_object.drr_toguid);
1038                 break;
1039         case DRR_FREEOBJECTS:
1040                 DO64(drr_freeobjects.drr_firstobj);
1041                 DO64(drr_freeobjects.drr_numobjs);
1042                 DO64(drr_freeobjects.drr_toguid);
1043                 break;
1044         case DRR_WRITE:
1045                 DO64(drr_write.drr_object);
1046                 DO32(drr_write.drr_type);
1047                 DO64(drr_write.drr_offset);
1048                 DO64(drr_write.drr_length);
1049                 DO64(drr_write.drr_toguid);
1050                 DO64(drr_write.drr_key.ddk_cksum.zc_word[0]);
1051                 DO64(drr_write.drr_key.ddk_cksum.zc_word[1]);
1052                 DO64(drr_write.drr_key.ddk_cksum.zc_word[2]);
1053                 DO64(drr_write.drr_key.ddk_cksum.zc_word[3]);
1054                 DO64(drr_write.drr_key.ddk_prop);
1055                 break;
1056         case DRR_WRITE_BYREF:
1057                 DO64(drr_write_byref.drr_object);
1058                 DO64(drr_write_byref.drr_offset);
1059                 DO64(drr_write_byref.drr_length);
1060                 DO64(drr_write_byref.drr_toguid);
1061                 DO64(drr_write_byref.drr_refguid);
1062                 DO64(drr_write_byref.drr_refobject);
1063                 DO64(drr_write_byref.drr_refoffset);
1064                 DO64(drr_write_byref.drr_key.ddk_cksum.zc_word[0]);
1065                 DO64(drr_write_byref.drr_key.ddk_cksum.zc_word[1]);
1066                 DO64(drr_write_byref.drr_key.ddk_cksum.zc_word[2]);
1067                 DO64(drr_write_byref.drr_key.ddk_cksum.zc_word[3]);
1068                 DO64(drr_write_byref.drr_key.ddk_prop);
1069                 break;
1070         case DRR_FREE:
1071                 DO64(drr_free.drr_object);
1072                 DO64(drr_free.drr_offset);
1073                 DO64(drr_free.drr_length);
1074                 DO64(drr_free.drr_toguid);
1075                 break;
1076         case DRR_SPILL:
1077                 DO64(drr_spill.drr_object);
1078                 DO64(drr_spill.drr_length);
1079                 DO64(drr_spill.drr_toguid);
1080                 break;
1081         case DRR_END:
1082                 DO64(drr_end.drr_checksum.zc_word[0]);
1083                 DO64(drr_end.drr_checksum.zc_word[1]);
1084                 DO64(drr_end.drr_checksum.zc_word[2]);
1085                 DO64(drr_end.drr_checksum.zc_word[3]);
1086                 DO64(drr_end.drr_toguid);
1087                 break;
1088         }
1089 #undef DO64
1090 #undef DO32
1091 }
1092 
1093 static int
1094 restore_object(struct restorearg *ra, objset_t *os, struct drr_object *drro)
1095 {
1096         int err;
1097         dmu_tx_t *tx;
1098         void *data = NULL;
1099 
1100         if (drro->drr_type == DMU_OT_NONE ||
1101             !DMU_OT_IS_VALID(drro->drr_type) ||
1102             !DMU_OT_IS_VALID(drro->drr_bonustype) ||
1103             drro->drr_checksumtype >= ZIO_CHECKSUM_FUNCTIONS ||
1104             drro->drr_compress >= ZIO_COMPRESS_FUNCTIONS ||
1105             P2PHASE(drro->drr_blksz, SPA_MINBLOCKSIZE) ||
1106             drro->drr_blksz < SPA_MINBLOCKSIZE ||
1107             drro->drr_blksz > SPA_MAXBLOCKSIZE ||
1108             drro->drr_bonuslen > DN_MAX_BONUSLEN) {
1109                 return (EINVAL);
1110         }
1111 
1112         err = dmu_object_info(os, drro->drr_object, NULL);
1113 
1114         if (err != 0 && err != ENOENT)
1115                 return (EINVAL);
1116 
1117         if (drro->drr_bonuslen) {
1118                 data = restore_read(ra, P2ROUNDUP(drro->drr_bonuslen, 8));
1119                 if (ra->err)
1120                         return (ra->err);
1121         }
1122 
1123         if (err == ENOENT) {
1124                 /* currently free, want to be allocated */
1125                 tx = dmu_tx_create(os);
1126                 dmu_tx_hold_bonus(tx, DMU_NEW_OBJECT);
1127                 err = dmu_tx_assign(tx, TXG_WAIT);
1128                 if (err) {
1129                         dmu_tx_abort(tx);
1130                         return (err);
1131                 }
1132                 err = dmu_object_claim(os, drro->drr_object,
1133                     drro->drr_type, drro->drr_blksz,
1134                     drro->drr_bonustype, drro->drr_bonuslen, tx);
1135                 dmu_tx_commit(tx);
1136         } else {
1137                 /* currently allocated, want to be allocated */
1138                 err = dmu_object_reclaim(os, drro->drr_object,
1139                     drro->drr_type, drro->drr_blksz,
1140                     drro->drr_bonustype, drro->drr_bonuslen);
1141         }
1142         if (err) {
1143                 return (EINVAL);
1144         }
1145 
1146         tx = dmu_tx_create(os);
1147         dmu_tx_hold_bonus(tx, drro->drr_object);
1148         err = dmu_tx_assign(tx, TXG_WAIT);
1149         if (err) {
1150                 dmu_tx_abort(tx);
1151                 return (err);
1152         }
1153 
1154         dmu_object_set_checksum(os, drro->drr_object, drro->drr_checksumtype,
1155             tx);
1156         dmu_object_set_compress(os, drro->drr_object, drro->drr_compress, tx);
1157 
1158         if (data != NULL) {
1159                 dmu_buf_t *db;
1160 
1161                 VERIFY(0 == dmu_bonus_hold(os, drro->drr_object, FTAG, &db));
1162                 dmu_buf_will_dirty(db, tx);
1163 
1164                 ASSERT3U(db->db_size, >=, drro->drr_bonuslen);
1165                 bcopy(data, db->db_data, drro->drr_bonuslen);
1166                 if (ra->byteswap) {
1167                         dmu_object_byteswap_t byteswap =
1168                             DMU_OT_BYTESWAP(drro->drr_bonustype);
1169                         dmu_ot_byteswap[byteswap].ob_func(db->db_data,
1170                             drro->drr_bonuslen);
1171                 }
1172                 dmu_buf_rele(db, FTAG);
1173         }
1174         dmu_tx_commit(tx);
1175         return (0);
1176 }
1177 
1178 /* ARGSUSED */
1179 static int
1180 restore_freeobjects(struct restorearg *ra, objset_t *os,
1181     struct drr_freeobjects *drrfo)
1182 {
1183         uint64_t obj;
1184 
1185         if (drrfo->drr_firstobj + drrfo->drr_numobjs < drrfo->drr_firstobj)
1186                 return (EINVAL);
1187 
1188         for (obj = drrfo->drr_firstobj;
1189             obj < drrfo->drr_firstobj + drrfo->drr_numobjs;
1190             (void) dmu_object_next(os, &obj, FALSE, 0)) {
1191                 int err;
1192 
1193                 if (dmu_object_info(os, obj, NULL) != 0)
1194                         continue;
1195 
1196                 err = dmu_free_object(os, obj);
1197                 if (err)
1198                         return (err);
1199         }
1200         return (0);
1201 }
1202 
1203 static int
1204 restore_write(struct restorearg *ra, objset_t *os,
1205     struct drr_write *drrw)
1206 {
1207         dmu_tx_t *tx;
1208         void *data;
1209         int err;
1210 
1211         if (drrw->drr_offset + drrw->drr_length < drrw->drr_offset ||
1212             !DMU_OT_IS_VALID(drrw->drr_type))
1213                 return (EINVAL);
1214 
1215         data = restore_read(ra, drrw->drr_length);
1216         if (data == NULL)
1217                 return (ra->err);
1218 
1219         if (dmu_object_info(os, drrw->drr_object, NULL) != 0)
1220                 return (EINVAL);
1221 
1222         tx = dmu_tx_create(os);
1223 
1224         dmu_tx_hold_write(tx, drrw->drr_object,
1225             drrw->drr_offset, drrw->drr_length);
1226         err = dmu_tx_assign(tx, TXG_WAIT);
1227         if (err) {
1228                 dmu_tx_abort(tx);
1229                 return (err);
1230         }
1231         if (ra->byteswap) {
1232                 dmu_object_byteswap_t byteswap =
1233                     DMU_OT_BYTESWAP(drrw->drr_type);
1234                 dmu_ot_byteswap[byteswap].ob_func(data, drrw->drr_length);
1235         }
1236         dmu_write(os, drrw->drr_object,
1237             drrw->drr_offset, drrw->drr_length, data, tx);
1238         dmu_tx_commit(tx);
1239         return (0);
1240 }
1241 
1242 /*
1243  * Handle a DRR_WRITE_BYREF record.  This record is used in dedup'ed
1244  * streams to refer to a copy of the data that is already on the
1245  * system because it came in earlier in the stream.  This function
1246  * finds the earlier copy of the data, and uses that copy instead of
1247  * data from the stream to fulfill this write.
1248  */
1249 static int
1250 restore_write_byref(struct restorearg *ra, objset_t *os,
1251     struct drr_write_byref *drrwbr)
1252 {
1253         dmu_tx_t *tx;
1254         int err;
1255         guid_map_entry_t gmesrch;
1256         guid_map_entry_t *gmep;
1257         avl_index_t     where;
1258         objset_t *ref_os = NULL;
1259         dmu_buf_t *dbp;
1260 
1261         if (drrwbr->drr_offset + drrwbr->drr_length < drrwbr->drr_offset)
1262                 return (EINVAL);
1263 
1264         /*
1265          * If the GUID of the referenced dataset is different from the
1266          * GUID of the target dataset, find the referenced dataset.
1267          */
1268         if (drrwbr->drr_toguid != drrwbr->drr_refguid) {
1269                 gmesrch.guid = drrwbr->drr_refguid;
1270                 if ((gmep = avl_find(ra->guid_to_ds_map, &gmesrch,
1271                     &where)) == NULL) {
1272                         return (EINVAL);
1273                 }
1274                 if (dmu_objset_from_ds(gmep->gme_ds, &ref_os))
1275                         return (EINVAL);
1276         } else {
1277                 ref_os = os;
1278         }
1279 
1280         if (err = dmu_buf_hold(ref_os, drrwbr->drr_refobject,
1281             drrwbr->drr_refoffset, FTAG, &dbp, DMU_READ_PREFETCH))
1282                 return (err);
1283 
1284         tx = dmu_tx_create(os);
1285 
1286         dmu_tx_hold_write(tx, drrwbr->drr_object,
1287             drrwbr->drr_offset, drrwbr->drr_length);
1288         err = dmu_tx_assign(tx, TXG_WAIT);
1289         if (err) {
1290                 dmu_tx_abort(tx);
1291                 return (err);
1292         }
1293         dmu_write(os, drrwbr->drr_object,
1294             drrwbr->drr_offset, drrwbr->drr_length, dbp->db_data, tx);
1295         dmu_buf_rele(dbp, FTAG);
1296         dmu_tx_commit(tx);
1297         return (0);
1298 }
1299 
1300 static int
1301 restore_spill(struct restorearg *ra, objset_t *os, struct drr_spill *drrs)
1302 {
1303         dmu_tx_t *tx;
1304         void *data;
1305         dmu_buf_t *db, *db_spill;
1306         int err;
1307 
1308         if (drrs->drr_length < SPA_MINBLOCKSIZE ||
1309             drrs->drr_length > SPA_MAXBLOCKSIZE)
1310                 return (EINVAL);
1311 
1312         data = restore_read(ra, drrs->drr_length);
1313         if (data == NULL)
1314                 return (ra->err);
1315 
1316         if (dmu_object_info(os, drrs->drr_object, NULL) != 0)
1317                 return (EINVAL);
1318 
1319         VERIFY(0 == dmu_bonus_hold(os, drrs->drr_object, FTAG, &db));
1320         if ((err = dmu_spill_hold_by_bonus(db, FTAG, &db_spill)) != 0) {
1321                 dmu_buf_rele(db, FTAG);
1322                 return (err);
1323         }
1324 
1325         tx = dmu_tx_create(os);
1326 
1327         dmu_tx_hold_spill(tx, db->db_object);
1328 
1329         err = dmu_tx_assign(tx, TXG_WAIT);
1330         if (err) {
1331                 dmu_buf_rele(db, FTAG);
1332                 dmu_buf_rele(db_spill, FTAG);
1333                 dmu_tx_abort(tx);
1334                 return (err);
1335         }
1336         dmu_buf_will_dirty(db_spill, tx);
1337 
1338         if (db_spill->db_size < drrs->drr_length)
1339                 VERIFY(0 == dbuf_spill_set_blksz(db_spill,
1340                     drrs->drr_length, tx));
1341         bcopy(data, db_spill->db_data, drrs->drr_length);
1342 
1343         dmu_buf_rele(db, FTAG);
1344         dmu_buf_rele(db_spill, FTAG);
1345 
1346         dmu_tx_commit(tx);
1347         return (0);
1348 }
1349 
1350 /* ARGSUSED */
1351 static int
1352 restore_free(struct restorearg *ra, objset_t *os,
1353     struct drr_free *drrf)
1354 {
1355         int err;
1356 
1357         if (drrf->drr_length != -1ULL &&
1358             drrf->drr_offset + drrf->drr_length < drrf->drr_offset)
1359                 return (EINVAL);
1360 
1361         if (dmu_object_info(os, drrf->drr_object, NULL) != 0)
1362                 return (EINVAL);
1363 
1364         err = dmu_free_long_range(os, drrf->drr_object,
1365             drrf->drr_offset, drrf->drr_length);
1366         return (err);
1367 }
1368 
1369 /*
1370  * NB: callers *must* call dmu_recv_end() if this succeeds.
1371  */
1372 int
1373 dmu_recv_stream(dmu_recv_cookie_t *drc, vnode_t *vp, offset_t *voffp,
1374     int cleanup_fd, uint64_t *action_handlep)
1375 {
1376         struct restorearg ra = { 0 };
1377         dmu_replay_record_t *drr;
1378         objset_t *os;
1379         zio_cksum_t pcksum;
1380         int featureflags;
1381 
1382         if (drc->drc_drrb->drr_magic == BSWAP_64(DMU_BACKUP_MAGIC))
1383                 ra.byteswap = TRUE;
1384 
1385         {
1386                 /* compute checksum of drr_begin record */
1387                 dmu_replay_record_t *drr;
1388                 drr = kmem_zalloc(sizeof (dmu_replay_record_t), KM_SLEEP);
1389 
1390                 drr->drr_type = DRR_BEGIN;
1391                 drr->drr_u.drr_begin = *drc->drc_drrb;
1392                 if (ra.byteswap) {
1393                         fletcher_4_incremental_byteswap(drr,
1394                             sizeof (dmu_replay_record_t), &ra.cksum);
1395                 } else {
1396                         fletcher_4_incremental_native(drr,
1397                             sizeof (dmu_replay_record_t), &ra.cksum);
1398                 }
1399                 kmem_free(drr, sizeof (dmu_replay_record_t));
1400         }
1401 
1402         if (ra.byteswap) {
1403                 struct drr_begin *drrb = drc->drc_drrb;
1404                 drrb->drr_magic = BSWAP_64(drrb->drr_magic);
1405                 drrb->drr_versioninfo = BSWAP_64(drrb->drr_versioninfo);
1406                 drrb->drr_creation_time = BSWAP_64(drrb->drr_creation_time);
1407                 drrb->drr_type = BSWAP_32(drrb->drr_type);
1408                 drrb->drr_toguid = BSWAP_64(drrb->drr_toguid);
1409                 drrb->drr_fromguid = BSWAP_64(drrb->drr_fromguid);
1410         }
1411 
1412         ra.vp = vp;
1413         ra.voff = *voffp;
1414         ra.bufsize = 1<<20;
1415         ra.buf = kmem_alloc(ra.bufsize, KM_SLEEP);
1416 
1417         /* these were verified in dmu_recv_begin */
1418         ASSERT(DMU_GET_STREAM_HDRTYPE(drc->drc_drrb->drr_versioninfo) ==
1419             DMU_SUBSTREAM);
1420         ASSERT(drc->drc_drrb->drr_type < DMU_OST_NUMTYPES);
1421 
1422         /*
1423          * Open the objset we are modifying.
1424          */
1425         VERIFY(dmu_objset_from_ds(drc->drc_real_ds, &os) == 0);
1426 
1427         ASSERT(drc->drc_real_ds->ds_phys->ds_flags & DS_FLAG_INCONSISTENT);
1428 
1429         featureflags = DMU_GET_FEATUREFLAGS(drc->drc_drrb->drr_versioninfo);
1430 
1431         /* if this stream is dedup'ed, set up the avl tree for guid mapping */
1432         if (featureflags & DMU_BACKUP_FEATURE_DEDUP) {
1433                 minor_t minor;
1434 
1435                 if (cleanup_fd == -1) {
1436                         ra.err = EBADF;
1437                         goto out;
1438                 }
1439                 ra.err = zfs_onexit_fd_hold(cleanup_fd, &minor);
1440                 if (ra.err) {
1441                         cleanup_fd = -1;
1442                         goto out;
1443                 }
1444 
1445                 if (*action_handlep == 0) {
1446                         ra.guid_to_ds_map =
1447                             kmem_alloc(sizeof (avl_tree_t), KM_SLEEP);
1448                         avl_create(ra.guid_to_ds_map, guid_compare,
1449                             sizeof (guid_map_entry_t),
1450                             offsetof(guid_map_entry_t, avlnode));
1451                         ra.err = zfs_onexit_add_cb(minor,
1452                             free_guid_map_onexit, ra.guid_to_ds_map,
1453                             action_handlep);
1454                         if (ra.err)
1455                                 goto out;
1456                 } else {
1457                         ra.err = zfs_onexit_cb_data(minor, *action_handlep,
1458                             (void **)&ra.guid_to_ds_map);
1459                         if (ra.err)
1460                                 goto out;
1461                 }
1462 
1463                 drc->drc_guid_to_ds_map = ra.guid_to_ds_map;
1464         }
1465 
1466         /*
1467          * Read records and process them.
1468          */
1469         pcksum = ra.cksum;
1470         while (ra.err == 0 &&
1471             NULL != (drr = restore_read(&ra, sizeof (*drr)))) {
1472                 if (issig(JUSTLOOKING) && issig(FORREAL)) {
1473                         ra.err = EINTR;
1474                         goto out;
1475                 }
1476 
1477                 if (ra.byteswap)
1478                         backup_byteswap(drr);
1479 
1480                 switch (drr->drr_type) {
1481                 case DRR_OBJECT:
1482                 {
1483                         /*
1484                          * We need to make a copy of the record header,
1485                          * because restore_{object,write} may need to
1486                          * restore_read(), which will invalidate drr.
1487                          */
1488                         struct drr_object drro = drr->drr_u.drr_object;
1489                         ra.err = restore_object(&ra, os, &drro);
1490                         break;
1491                 }
1492                 case DRR_FREEOBJECTS:
1493                 {
1494                         struct drr_freeobjects drrfo =
1495                             drr->drr_u.drr_freeobjects;
1496                         ra.err = restore_freeobjects(&ra, os, &drrfo);
1497                         break;
1498                 }
1499                 case DRR_WRITE:
1500                 {
1501                         struct drr_write drrw = drr->drr_u.drr_write;
1502                         ra.err = restore_write(&ra, os, &drrw);
1503                         break;
1504                 }
1505                 case DRR_WRITE_BYREF:
1506                 {
1507                         struct drr_write_byref drrwbr =
1508                             drr->drr_u.drr_write_byref;
1509                         ra.err = restore_write_byref(&ra, os, &drrwbr);
1510                         break;
1511                 }
1512                 case DRR_FREE:
1513                 {
1514                         struct drr_free drrf = drr->drr_u.drr_free;
1515                         ra.err = restore_free(&ra, os, &drrf);
1516                         break;
1517                 }
1518                 case DRR_END:
1519                 {
1520                         struct drr_end drre = drr->drr_u.drr_end;
1521                         /*
1522                          * We compare against the *previous* checksum
1523                          * value, because the stored checksum is of
1524                          * everything before the DRR_END record.
1525                          */
1526                         if (!ZIO_CHECKSUM_EQUAL(drre.drr_checksum, pcksum))
1527                                 ra.err = ECKSUM;
1528                         goto out;
1529                 }
1530                 case DRR_SPILL:
1531                 {
1532                         struct drr_spill drrs = drr->drr_u.drr_spill;
1533                         ra.err = restore_spill(&ra, os, &drrs);
1534                         break;
1535                 }
1536                 default:
1537                         ra.err = EINVAL;
1538                         goto out;
1539                 }
1540                 pcksum = ra.cksum;
1541         }
1542         ASSERT(ra.err != 0);
1543 
1544 out:
1545         if ((featureflags & DMU_BACKUP_FEATURE_DEDUP) && (cleanup_fd != -1))
1546                 zfs_onexit_fd_rele(cleanup_fd);
1547 
1548         if (ra.err != 0) {
1549                 /*
1550                  * destroy what we created, so we don't leave it in the
1551                  * inconsistent restoring state.
1552                  */
1553                 txg_wait_synced(drc->drc_real_ds->ds_dir->dd_pool, 0);
1554 
1555                 (void) dsl_dataset_destroy(drc->drc_real_ds, dmu_recv_tag,
1556                     B_FALSE);
1557                 if (drc->drc_real_ds != drc->drc_logical_ds) {
1558                         mutex_exit(&drc->drc_logical_ds->ds_recvlock);
1559                         dsl_dataset_rele(drc->drc_logical_ds, dmu_recv_tag);
1560                 }
1561         }
1562 
1563         kmem_free(ra.buf, ra.bufsize);
1564         *voffp = ra.voff;
1565         return (ra.err);
1566 }
1567 
1568 struct recvendsyncarg {
1569         char *tosnap;
1570         uint64_t creation_time;
1571         uint64_t toguid;
1572         boolean_t is_new;
1573 };
1574 
1575 static int
1576 recv_end_check(void *arg1, void *arg2, dmu_tx_t *tx)
1577 {
1578         dsl_dataset_t *ds = arg1;
1579         struct recvendsyncarg *resa = arg2;
1580 
1581         if (resa->is_new) {
1582                 /* re-check the dataset quota now that recv is complete */
1583                 dsl_dir_t *dd;
1584                 int err;
1585 
1586                 dd = ds->ds_dir;
1587                 if (dd->dd_parent != NULL) {
1588                         err = dsl_dir_dscount_check(dd->dd_parent, NULL, 1,
1589                             NULL);
1590                         if (err != 0)
1591                                 return (err);
1592                 }
1593         }
1594 
1595         return (dsl_dataset_snapshot_check(ds, resa->tosnap, 1, tx));
1596 }
1597 
1598 static void
1599 recv_end_sync(void *arg1, void *arg2, dmu_tx_t *tx)
1600 {
1601         dsl_dataset_t *ds = arg1;
1602         struct recvendsyncarg *resa = arg2;
1603 
1604         if (resa->is_new)
1605                 /* update the dataset counts */
1606                 dsl_dir_dscount_adjust(ds->ds_dir->dd_parent, tx, 1, B_FALSE,
1607                     B_TRUE);
1608 
1609         dsl_dataset_snapshot_sync(ds, resa->tosnap, tx);
1610 
1611         /* set snapshot's creation time and guid */
1612         dmu_buf_will_dirty(ds->ds_prev->ds_dbuf, tx);
1613         ds->ds_prev->ds_phys->ds_creation_time = resa->creation_time;
1614         ds->ds_prev->ds_phys->ds_guid = resa->toguid;
1615         ds->ds_prev->ds_phys->ds_flags &= ~DS_FLAG_INCONSISTENT;
1616 
1617         dmu_buf_will_dirty(ds->ds_dbuf, tx);
1618         ds->ds_phys->ds_flags &= ~DS_FLAG_INCONSISTENT;
1619         spa_history_log_internal_ds(ds, "finished receiving", tx, "");
1620 }
1621 
1622 static int
1623 add_ds_to_guidmap(avl_tree_t *guid_map, dsl_dataset_t *ds)
1624 {
1625         dsl_pool_t *dp = ds->ds_dir->dd_pool;
1626         uint64_t snapobj = ds->ds_phys->ds_prev_snap_obj;
1627         dsl_dataset_t *snapds;
1628         guid_map_entry_t *gmep;
1629         int err;
1630 
1631         ASSERT(guid_map != NULL);
1632 
1633         rw_enter(&dp->dp_config_rwlock, RW_READER);
1634         err = dsl_dataset_hold_obj(dp, snapobj, guid_map, &snapds);
1635         if (err == 0) {
1636                 gmep = kmem_alloc(sizeof (guid_map_entry_t), KM_SLEEP);
1637                 gmep->guid = snapds->ds_phys->ds_guid;
1638                 gmep->gme_ds = snapds;
1639                 avl_add(guid_map, gmep);
1640         }
1641 
1642         rw_exit(&dp->dp_config_rwlock);
1643         return (err);
1644 }
1645 
1646 static int
1647 dmu_recv_existing_end(dmu_recv_cookie_t *drc)
1648 {
1649         struct recvendsyncarg resa;
1650         dsl_dataset_t *ds = drc->drc_logical_ds;
1651         int err, myerr;
1652 
1653         if (dsl_dataset_tryown(ds, FALSE, dmu_recv_tag)) {
1654                 err = dsl_dataset_clone_swap(drc->drc_real_ds, ds,
1655                     drc->drc_force);
1656                 if (err)
1657                         goto out;
1658         } else {
1659                 mutex_exit(&ds->ds_recvlock);
1660                 dsl_dataset_rele(ds, dmu_recv_tag);
1661                 /* tag indicates temporary ds to dsl_dir_destroy_sync */
1662                 (void) dsl_dataset_destroy(drc->drc_real_ds, tmp_dmu_recv_tag,
1663                     B_FALSE);
1664                 return (EBUSY);
1665         }
1666 
1667         resa.creation_time = drc->drc_drrb->drr_creation_time;
1668         resa.toguid = drc->drc_drrb->drr_toguid;
1669         resa.tosnap = drc->drc_tosnap;
1670         resa.is_new = B_FALSE;
1671 
1672         err = dsl_sync_task_do(ds->ds_dir->dd_pool,
1673             recv_end_check, recv_end_sync, ds, &resa, 3);
1674         if (err) {
1675                 /* swap back */
1676                 (void) dsl_dataset_clone_swap(drc->drc_real_ds, ds, B_TRUE);
1677         }
1678 
1679 out:
1680         mutex_exit(&ds->ds_recvlock);
1681         if (err == 0 && drc->drc_guid_to_ds_map != NULL)
1682                 (void) add_ds_to_guidmap(drc->drc_guid_to_ds_map, ds);
1683         dsl_dataset_disown(ds, dmu_recv_tag);
1684         /* tag indicates temporary ds to dsl_dir_destroy_sync */
1685         myerr = dsl_dataset_destroy(drc->drc_real_ds, tmp_dmu_recv_tag,
1686             B_FALSE);
1687         ASSERT0(myerr);
1688         return (err);
1689 }
1690 
1691 static int
1692 dmu_recv_new_end(dmu_recv_cookie_t *drc)
1693 {
1694         struct recvendsyncarg resa;
1695         dsl_dataset_t *ds = drc->drc_logical_ds;
1696         int err;
1697 
1698         /*
1699          * XXX hack; seems the ds is still dirty and dsl_pool_zil_clean()
1700          * expects it to have a ds_user_ptr (and zil), but clone_swap()
1701          * can close it.
1702          */
1703         txg_wait_synced(ds->ds_dir->dd_pool, 0);
1704 
1705         resa.creation_time = drc->drc_drrb->drr_creation_time;
1706         resa.toguid = drc->drc_drrb->drr_toguid;
1707         resa.tosnap = drc->drc_tosnap;
1708         resa.is_new = B_TRUE;
1709 
1710         err = dsl_sync_task_do(ds->ds_dir->dd_pool,
1711             recv_end_check, recv_end_sync, ds, &resa, 3);
1712         if (err) {
1713                 /* clean up the fs we just recv'd into */
1714                 (void) dsl_dataset_destroy(ds, dmu_recv_tag, B_FALSE);
1715         } else {
1716                 if (drc->drc_guid_to_ds_map != NULL)
1717                         (void) add_ds_to_guidmap(drc->drc_guid_to_ds_map, ds);
1718                 /* release the hold from dmu_recv_begin */
1719                 dsl_dataset_disown(ds, dmu_recv_tag);
1720         }
1721         return (err);
1722 }
1723 
1724 int
1725 dmu_recv_end(dmu_recv_cookie_t *drc)
1726 {
1727         if (drc->drc_logical_ds != drc->drc_real_ds)
1728                 return (dmu_recv_existing_end(drc));
1729         else
1730                 return (dmu_recv_new_end(drc));
1731 }