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