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) 2011, 2015 by Delphix. All rights reserved.
  25  * Copyright (c) 2014, Joyent, Inc. All rights reserved.
  26  * Copyright 2014 HybridCluster. All rights reserved.
  27  * Copyright 2016 RackTop Systems.
  28  * Copyright (c) 2014 Integros [integros.com]
  29  */
  30 
  31 #include <sys/dmu.h>
  32 #include <sys/dmu_impl.h>
  33 #include <sys/dmu_tx.h>
  34 #include <sys/dbuf.h>
  35 #include <sys/dnode.h>
  36 #include <sys/zfs_context.h>
  37 #include <sys/dmu_objset.h>
  38 #include <sys/dmu_traverse.h>
  39 #include <sys/dsl_dataset.h>
  40 #include <sys/dsl_dir.h>
  41 #include <sys/dsl_prop.h>
  42 #include <sys/dsl_pool.h>
  43 #include <sys/dsl_synctask.h>
  44 #include <sys/zfs_ioctl.h>
  45 #include <sys/zap.h>
  46 #include <sys/zio_checksum.h>
  47 #include <sys/zfs_znode.h>
  48 #include <zfs_fletcher.h>
  49 #include <sys/avl.h>
  50 #include <sys/ddt.h>
  51 #include <sys/zfs_onexit.h>
  52 #include <sys/dmu_send.h>
  53 #include <sys/dsl_destroy.h>
  54 #include <sys/blkptr.h>
  55 #include <sys/dsl_bookmark.h>
  56 #include <sys/zfeature.h>
  57 #include <sys/bqueue.h>
  58 
  59 /* Set this tunable to TRUE to replace corrupt data with 0x2f5baddb10c */
  60 int zfs_send_corrupt_data = B_FALSE;
  61 int zfs_send_queue_length = 16 * 1024 * 1024;
  62 int zfs_recv_queue_length = 16 * 1024 * 1024;
  63 /* Set this tunable to FALSE to disable setting of DRR_FLAG_FREERECORDS */
  64 int zfs_send_set_freerecords_bit = B_TRUE;
  65 
  66 static char *dmu_recv_tag = "dmu_recv_tag";
  67 const char *recv_clone_name = "%recv";
  68 
  69 #define BP_SPAN(datablkszsec, indblkshift, level) \
  70         (((uint64_t)datablkszsec) << (SPA_MINBLOCKSHIFT + \
  71         (level) * (indblkshift - SPA_BLKPTRSHIFT)))
  72 
  73 static void byteswap_record(dmu_replay_record_t *drr);
  74 
  75 struct send_thread_arg {
  76         bqueue_t        q;
  77         dsl_dataset_t   *ds;            /* Dataset to traverse */
  78         uint64_t        fromtxg;        /* Traverse from this txg */
  79         int             flags;          /* flags to pass to traverse_dataset */
  80         int             error_code;
  81         boolean_t       cancel;
  82         zbookmark_phys_t resume;
  83 };
  84 
  85 struct send_block_record {
  86         boolean_t               eos_marker; /* Marks the end of the stream */
  87         blkptr_t                bp;
  88         zbookmark_phys_t        zb;
  89         uint8_t                 indblkshift;
  90         uint16_t                datablkszsec;
  91         bqueue_node_t           ln;
  92 };
  93 
  94 static int
  95 dump_bytes(dmu_sendarg_t *dsp, void *buf, int len)
  96 {
  97         dsl_dataset_t *ds = dmu_objset_ds(dsp->dsa_os);
  98         ssize_t resid; /* have to get resid to get detailed errno */
  99 
 100         /*
 101          * The code does not rely on this (len being a multiple of 8).  We keep
 102          * this assertion because of the corresponding assertion in
 103          * receive_read().  Keeping this assertion ensures that we do not
 104          * inadvertently break backwards compatibility (causing the assertion
 105          * in receive_read() to trigger on old software).
 106          *
 107          * Removing the assertions could be rolled into a new feature that uses
 108          * data that isn't 8-byte aligned; if the assertions were removed, a
 109          * feature flag would have to be added.
 110          */
 111 
 112         ASSERT0(len % 8);
 113 
 114         dsp->dsa_err = vn_rdwr(UIO_WRITE, dsp->dsa_vp,
 115             (caddr_t)buf, len,
 116             0, UIO_SYSSPACE, FAPPEND, RLIM64_INFINITY, CRED(), &resid);
 117 
 118         mutex_enter(&ds->ds_sendstream_lock);
 119         *dsp->dsa_off += len;
 120         mutex_exit(&ds->ds_sendstream_lock);
 121 
 122         return (dsp->dsa_err);
 123 }
 124 
 125 /*
 126  * For all record types except BEGIN, fill in the checksum (overlaid in
 127  * drr_u.drr_checksum.drr_checksum).  The checksum verifies everything
 128  * up to the start of the checksum itself.
 129  */
 130 static int
 131 dump_record(dmu_sendarg_t *dsp, void *payload, int payload_len)
 132 {
 133         ASSERT3U(offsetof(dmu_replay_record_t, drr_u.drr_checksum.drr_checksum),
 134             ==, sizeof (dmu_replay_record_t) - sizeof (zio_cksum_t));
 135         fletcher_4_incremental_native(dsp->dsa_drr,
 136             offsetof(dmu_replay_record_t, drr_u.drr_checksum.drr_checksum),
 137             &dsp->dsa_zc);
 138         if (dsp->dsa_drr->drr_type != DRR_BEGIN) {
 139                 ASSERT(ZIO_CHECKSUM_IS_ZERO(&dsp->dsa_drr->drr_u.
 140                     drr_checksum.drr_checksum));
 141                 dsp->dsa_drr->drr_u.drr_checksum.drr_checksum = dsp->dsa_zc;
 142         }
 143         fletcher_4_incremental_native(&dsp->dsa_drr->
 144             drr_u.drr_checksum.drr_checksum,
 145             sizeof (zio_cksum_t), &dsp->dsa_zc);
 146         if (dump_bytes(dsp, dsp->dsa_drr, sizeof (dmu_replay_record_t)) != 0)
 147                 return (SET_ERROR(EINTR));
 148         if (payload_len != 0) {
 149                 fletcher_4_incremental_native(payload, payload_len,
 150                     &dsp->dsa_zc);
 151                 if (dump_bytes(dsp, payload, payload_len) != 0)
 152                         return (SET_ERROR(EINTR));
 153         }
 154         return (0);
 155 }
 156 
 157 /*
 158  * Fill in the drr_free struct, or perform aggregation if the previous record is
 159  * also a free record, and the two are adjacent.
 160  *
 161  * Note that we send free records even for a full send, because we want to be
 162  * able to receive a full send as a clone, which requires a list of all the free
 163  * and freeobject records that were generated on the source.
 164  */
 165 static int
 166 dump_free(dmu_sendarg_t *dsp, uint64_t object, uint64_t offset,
 167     uint64_t length)
 168 {
 169         struct drr_free *drrf = &(dsp->dsa_drr->drr_u.drr_free);
 170 
 171         /*
 172          * When we receive a free record, dbuf_free_range() assumes
 173          * that the receiving system doesn't have any dbufs in the range
 174          * being freed.  This is always true because there is a one-record
 175          * constraint: we only send one WRITE record for any given
 176          * object,offset.  We know that the one-record constraint is
 177          * true because we always send data in increasing order by
 178          * object,offset.
 179          *
 180          * If the increasing-order constraint ever changes, we should find
 181          * another way to assert that the one-record constraint is still
 182          * satisfied.
 183          */
 184         ASSERT(object > dsp->dsa_last_data_object ||
 185             (object == dsp->dsa_last_data_object &&
 186             offset > dsp->dsa_last_data_offset));
 187 
 188         if (length != -1ULL && offset + length < offset)
 189                 length = -1ULL;
 190 
 191         /*
 192          * If there is a pending op, but it's not PENDING_FREE, push it out,
 193          * since free block aggregation can only be done for blocks of the
 194          * same type (i.e., DRR_FREE records can only be aggregated with
 195          * other DRR_FREE records.  DRR_FREEOBJECTS records can only be
 196          * aggregated with other DRR_FREEOBJECTS records.
 197          */
 198         if (dsp->dsa_pending_op != PENDING_NONE &&
 199             dsp->dsa_pending_op != PENDING_FREE) {
 200                 if (dump_record(dsp, NULL, 0) != 0)
 201                         return (SET_ERROR(EINTR));
 202                 dsp->dsa_pending_op = PENDING_NONE;
 203         }
 204 
 205         if (dsp->dsa_pending_op == PENDING_FREE) {
 206                 /*
 207                  * There should never be a PENDING_FREE if length is -1
 208                  * (because dump_dnode is the only place where this
 209                  * function is called with a -1, and only after flushing
 210                  * any pending record).
 211                  */
 212                 ASSERT(length != -1ULL);
 213                 /*
 214                  * Check to see whether this free block can be aggregated
 215                  * with pending one.
 216                  */
 217                 if (drrf->drr_object == object && drrf->drr_offset +
 218                     drrf->drr_length == offset) {
 219                         drrf->drr_length += length;
 220                         return (0);
 221                 } else {
 222                         /* not a continuation.  Push out pending record */
 223                         if (dump_record(dsp, NULL, 0) != 0)
 224                                 return (SET_ERROR(EINTR));
 225                         dsp->dsa_pending_op = PENDING_NONE;
 226                 }
 227         }
 228         /* create a FREE record and make it pending */
 229         bzero(dsp->dsa_drr, sizeof (dmu_replay_record_t));
 230         dsp->dsa_drr->drr_type = DRR_FREE;
 231         drrf->drr_object = object;
 232         drrf->drr_offset = offset;
 233         drrf->drr_length = length;
 234         drrf->drr_toguid = dsp->dsa_toguid;
 235         if (length == -1ULL) {
 236                 if (dump_record(dsp, NULL, 0) != 0)
 237                         return (SET_ERROR(EINTR));
 238         } else {
 239                 dsp->dsa_pending_op = PENDING_FREE;
 240         }
 241 
 242         return (0);
 243 }
 244 
 245 static int
 246 dump_write(dmu_sendarg_t *dsp, dmu_object_type_t type,
 247     uint64_t object, uint64_t offset, int blksz, const blkptr_t *bp, void *data)
 248 {
 249         struct drr_write *drrw = &(dsp->dsa_drr->drr_u.drr_write);
 250 
 251         /*
 252          * We send data in increasing object, offset order.
 253          * See comment in dump_free() for details.
 254          */
 255         ASSERT(object > dsp->dsa_last_data_object ||
 256             (object == dsp->dsa_last_data_object &&
 257             offset > dsp->dsa_last_data_offset));
 258         dsp->dsa_last_data_object = object;
 259         dsp->dsa_last_data_offset = offset + blksz - 1;
 260 
 261         /*
 262          * If there is any kind of pending aggregation (currently either
 263          * a grouping of free objects or free blocks), push it out to
 264          * the stream, since aggregation can't be done across operations
 265          * of different types.
 266          */
 267         if (dsp->dsa_pending_op != PENDING_NONE) {
 268                 if (dump_record(dsp, NULL, 0) != 0)
 269                         return (SET_ERROR(EINTR));
 270                 dsp->dsa_pending_op = PENDING_NONE;
 271         }
 272         /* write a WRITE record */
 273         bzero(dsp->dsa_drr, sizeof (dmu_replay_record_t));
 274         dsp->dsa_drr->drr_type = DRR_WRITE;
 275         drrw->drr_object = object;
 276         drrw->drr_type = type;
 277         drrw->drr_offset = offset;
 278         drrw->drr_length = blksz;
 279         drrw->drr_toguid = dsp->dsa_toguid;
 280         if (bp == NULL || BP_IS_EMBEDDED(bp)) {
 281                 /*
 282                  * There's no pre-computed checksum for partial-block
 283                  * writes or embedded BP's, so (like
 284                  * fletcher4-checkummed blocks) userland will have to
 285                  * compute a dedup-capable checksum itself.
 286                  */
 287                 drrw->drr_checksumtype = ZIO_CHECKSUM_OFF;
 288         } else {
 289                 drrw->drr_checksumtype = BP_GET_CHECKSUM(bp);
 290                 if (zio_checksum_table[drrw->drr_checksumtype].ci_flags &
 291                     ZCHECKSUM_FLAG_DEDUP)
 292                         drrw->drr_checksumflags |= DRR_CHECKSUM_DEDUP;
 293                 DDK_SET_LSIZE(&drrw->drr_key, BP_GET_LSIZE(bp));
 294                 DDK_SET_PSIZE(&drrw->drr_key, BP_GET_PSIZE(bp));
 295                 DDK_SET_COMPRESS(&drrw->drr_key, BP_GET_COMPRESS(bp));
 296                 drrw->drr_key.ddk_cksum = bp->blk_cksum;
 297         }
 298 
 299         if (dump_record(dsp, data, blksz) != 0)
 300                 return (SET_ERROR(EINTR));
 301         return (0);
 302 }
 303 
 304 static int
 305 dump_write_embedded(dmu_sendarg_t *dsp, uint64_t object, uint64_t offset,
 306     int blksz, const blkptr_t *bp)
 307 {
 308         char buf[BPE_PAYLOAD_SIZE];
 309         struct drr_write_embedded *drrw =
 310             &(dsp->dsa_drr->drr_u.drr_write_embedded);
 311 
 312         if (dsp->dsa_pending_op != PENDING_NONE) {
 313                 if (dump_record(dsp, NULL, 0) != 0)
 314                         return (EINTR);
 315                 dsp->dsa_pending_op = PENDING_NONE;
 316         }
 317 
 318         ASSERT(BP_IS_EMBEDDED(bp));
 319 
 320         bzero(dsp->dsa_drr, sizeof (dmu_replay_record_t));
 321         dsp->dsa_drr->drr_type = DRR_WRITE_EMBEDDED;
 322         drrw->drr_object = object;
 323         drrw->drr_offset = offset;
 324         drrw->drr_length = blksz;
 325         drrw->drr_toguid = dsp->dsa_toguid;
 326         drrw->drr_compression = BP_GET_COMPRESS(bp);
 327         drrw->drr_etype = BPE_GET_ETYPE(bp);
 328         drrw->drr_lsize = BPE_GET_LSIZE(bp);
 329         drrw->drr_psize = BPE_GET_PSIZE(bp);
 330 
 331         decode_embedded_bp_compressed(bp, buf);
 332 
 333         if (dump_record(dsp, buf, P2ROUNDUP(drrw->drr_psize, 8)) != 0)
 334                 return (EINTR);
 335         return (0);
 336 }
 337 
 338 static int
 339 dump_spill(dmu_sendarg_t *dsp, uint64_t object, int blksz, void *data)
 340 {
 341         struct drr_spill *drrs = &(dsp->dsa_drr->drr_u.drr_spill);
 342 
 343         if (dsp->dsa_pending_op != PENDING_NONE) {
 344                 if (dump_record(dsp, NULL, 0) != 0)
 345                         return (SET_ERROR(EINTR));
 346                 dsp->dsa_pending_op = PENDING_NONE;
 347         }
 348 
 349         /* write a SPILL record */
 350         bzero(dsp->dsa_drr, sizeof (dmu_replay_record_t));
 351         dsp->dsa_drr->drr_type = DRR_SPILL;
 352         drrs->drr_object = object;
 353         drrs->drr_length = blksz;
 354         drrs->drr_toguid = dsp->dsa_toguid;
 355 
 356         if (dump_record(dsp, data, blksz) != 0)
 357                 return (SET_ERROR(EINTR));
 358         return (0);
 359 }
 360 
 361 static int
 362 dump_freeobjects(dmu_sendarg_t *dsp, uint64_t firstobj, uint64_t numobjs)
 363 {
 364         struct drr_freeobjects *drrfo = &(dsp->dsa_drr->drr_u.drr_freeobjects);
 365 
 366         /*
 367          * If there is a pending op, but it's not PENDING_FREEOBJECTS,
 368          * push it out, since free block aggregation can only be done for
 369          * blocks of the same type (i.e., DRR_FREE records can only be
 370          * aggregated with other DRR_FREE records.  DRR_FREEOBJECTS records
 371          * can only be aggregated with other DRR_FREEOBJECTS records.
 372          */
 373         if (dsp->dsa_pending_op != PENDING_NONE &&
 374             dsp->dsa_pending_op != PENDING_FREEOBJECTS) {
 375                 if (dump_record(dsp, NULL, 0) != 0)
 376                         return (SET_ERROR(EINTR));
 377                 dsp->dsa_pending_op = PENDING_NONE;
 378         }
 379         if (dsp->dsa_pending_op == PENDING_FREEOBJECTS) {
 380                 /*
 381                  * See whether this free object array can be aggregated
 382                  * with pending one
 383                  */
 384                 if (drrfo->drr_firstobj + drrfo->drr_numobjs == firstobj) {
 385                         drrfo->drr_numobjs += numobjs;
 386                         return (0);
 387                 } else {
 388                         /* can't be aggregated.  Push out pending record */
 389                         if (dump_record(dsp, NULL, 0) != 0)
 390                                 return (SET_ERROR(EINTR));
 391                         dsp->dsa_pending_op = PENDING_NONE;
 392                 }
 393         }
 394 
 395         /* write a FREEOBJECTS record */
 396         bzero(dsp->dsa_drr, sizeof (dmu_replay_record_t));
 397         dsp->dsa_drr->drr_type = DRR_FREEOBJECTS;
 398         drrfo->drr_firstobj = firstobj;
 399         drrfo->drr_numobjs = numobjs;
 400         drrfo->drr_toguid = dsp->dsa_toguid;
 401 
 402         dsp->dsa_pending_op = PENDING_FREEOBJECTS;
 403 
 404         return (0);
 405 }
 406 
 407 static int
 408 dump_dnode(dmu_sendarg_t *dsp, uint64_t object, dnode_phys_t *dnp)
 409 {
 410         struct drr_object *drro = &(dsp->dsa_drr->drr_u.drr_object);
 411 
 412         if (object < dsp->dsa_resume_object) {
 413                 /*
 414                  * Note: when resuming, we will visit all the dnodes in
 415                  * the block of dnodes that we are resuming from.  In
 416                  * this case it's unnecessary to send the dnodes prior to
 417                  * the one we are resuming from.  We should be at most one
 418                  * block's worth of dnodes behind the resume point.
 419                  */
 420                 ASSERT3U(dsp->dsa_resume_object - object, <,
 421                     1 << (DNODE_BLOCK_SHIFT - DNODE_SHIFT));
 422                 return (0);
 423         }
 424 
 425         if (dnp == NULL || dnp->dn_type == DMU_OT_NONE)
 426                 return (dump_freeobjects(dsp, object, 1));
 427 
 428         if (dsp->dsa_pending_op != PENDING_NONE) {
 429                 if (dump_record(dsp, NULL, 0) != 0)
 430                         return (SET_ERROR(EINTR));
 431                 dsp->dsa_pending_op = PENDING_NONE;
 432         }
 433 
 434         /* write an OBJECT record */
 435         bzero(dsp->dsa_drr, sizeof (dmu_replay_record_t));
 436         dsp->dsa_drr->drr_type = DRR_OBJECT;
 437         drro->drr_object = object;
 438         drro->drr_type = dnp->dn_type;
 439         drro->drr_bonustype = dnp->dn_bonustype;
 440         drro->drr_blksz = dnp->dn_datablkszsec << SPA_MINBLOCKSHIFT;
 441         drro->drr_bonuslen = dnp->dn_bonuslen;
 442         drro->drr_checksumtype = dnp->dn_checksum;
 443         drro->drr_compress = dnp->dn_compress;
 444         drro->drr_toguid = dsp->dsa_toguid;
 445 
 446         if (!(dsp->dsa_featureflags & DMU_BACKUP_FEATURE_LARGE_BLOCKS) &&
 447             drro->drr_blksz > SPA_OLD_MAXBLOCKSIZE)
 448                 drro->drr_blksz = SPA_OLD_MAXBLOCKSIZE;
 449 
 450         if (dump_record(dsp, DN_BONUS(dnp),
 451             P2ROUNDUP(dnp->dn_bonuslen, 8)) != 0) {
 452                 return (SET_ERROR(EINTR));
 453         }
 454 
 455         /* Free anything past the end of the file. */
 456         if (dump_free(dsp, object, (dnp->dn_maxblkid + 1) *
 457             (dnp->dn_datablkszsec << SPA_MINBLOCKSHIFT), -1ULL) != 0)
 458                 return (SET_ERROR(EINTR));
 459         if (dsp->dsa_err != 0)
 460                 return (SET_ERROR(EINTR));
 461         return (0);
 462 }
 463 
 464 static boolean_t
 465 backup_do_embed(dmu_sendarg_t *dsp, const blkptr_t *bp)
 466 {
 467         if (!BP_IS_EMBEDDED(bp))
 468                 return (B_FALSE);
 469 
 470         /*
 471          * Compression function must be legacy, or explicitly enabled.
 472          */
 473         if ((BP_GET_COMPRESS(bp) >= ZIO_COMPRESS_LEGACY_FUNCTIONS &&
 474             !(dsp->dsa_featureflags & DMU_BACKUP_FEATURE_EMBED_DATA_LZ4)))
 475                 return (B_FALSE);
 476 
 477         /*
 478          * Embed type must be explicitly enabled.
 479          */
 480         switch (BPE_GET_ETYPE(bp)) {
 481         case BP_EMBEDDED_TYPE_DATA:
 482                 if (dsp->dsa_featureflags & DMU_BACKUP_FEATURE_EMBED_DATA)
 483                         return (B_TRUE);
 484                 break;
 485         default:
 486                 return (B_FALSE);
 487         }
 488         return (B_FALSE);
 489 }
 490 
 491 /*
 492  * This is the callback function to traverse_dataset that acts as the worker
 493  * thread for dmu_send_impl.
 494  */
 495 /*ARGSUSED*/
 496 static int
 497 send_cb(spa_t *spa, zilog_t *zilog, const blkptr_t *bp,
 498     const zbookmark_phys_t *zb, const struct dnode_phys *dnp, void *arg)
 499 {
 500         struct send_thread_arg *sta = arg;
 501         struct send_block_record *record;
 502         uint64_t record_size;
 503         int err = 0;
 504 
 505         ASSERT(zb->zb_object == DMU_META_DNODE_OBJECT ||
 506             zb->zb_object >= sta->resume.zb_object);
 507 
 508         if (sta->cancel)
 509                 return (SET_ERROR(EINTR));
 510 
 511         if (bp == NULL) {
 512                 ASSERT3U(zb->zb_level, ==, ZB_DNODE_LEVEL);
 513                 return (0);
 514         } else if (zb->zb_level < 0) {
 515                 return (0);
 516         }
 517 
 518         record = kmem_zalloc(sizeof (struct send_block_record), KM_SLEEP);
 519         record->eos_marker = B_FALSE;
 520         record->bp = *bp;
 521         record->zb = *zb;
 522         record->indblkshift = dnp->dn_indblkshift;
 523         record->datablkszsec = dnp->dn_datablkszsec;
 524         record_size = dnp->dn_datablkszsec << SPA_MINBLOCKSHIFT;
 525         bqueue_enqueue(&sta->q, record, record_size);
 526 
 527         return (err);
 528 }
 529 
 530 /*
 531  * This function kicks off the traverse_dataset.  It also handles setting the
 532  * error code of the thread in case something goes wrong, and pushes the End of
 533  * Stream record when the traverse_dataset call has finished.  If there is no
 534  * dataset to traverse, the thread immediately pushes End of Stream marker.
 535  */
 536 static void
 537 send_traverse_thread(void *arg)
 538 {
 539         struct send_thread_arg *st_arg = arg;
 540         int err;
 541         struct send_block_record *data;
 542 
 543         if (st_arg->ds != NULL) {
 544                 err = traverse_dataset_resume(st_arg->ds,
 545                     st_arg->fromtxg, &st_arg->resume,
 546                     st_arg->flags, send_cb, st_arg);
 547 
 548                 if (err != EINTR)
 549                         st_arg->error_code = err;
 550         }
 551         data = kmem_zalloc(sizeof (*data), KM_SLEEP);
 552         data->eos_marker = B_TRUE;
 553         bqueue_enqueue(&st_arg->q, data, 1);
 554 }
 555 
 556 /*
 557  * This function actually handles figuring out what kind of record needs to be
 558  * dumped, reading the data (which has hopefully been prefetched), and calling
 559  * the appropriate helper function.
 560  */
 561 static int
 562 do_dump(dmu_sendarg_t *dsa, struct send_block_record *data)
 563 {
 564         dsl_dataset_t *ds = dmu_objset_ds(dsa->dsa_os);
 565         const blkptr_t *bp = &data->bp;
 566         const zbookmark_phys_t *zb = &data->zb;
 567         uint8_t indblkshift = data->indblkshift;
 568         uint16_t dblkszsec = data->datablkszsec;
 569         spa_t *spa = ds->ds_dir->dd_pool->dp_spa;
 570         dmu_object_type_t type = bp ? BP_GET_TYPE(bp) : DMU_OT_NONE;
 571         int err = 0;
 572 
 573         ASSERT3U(zb->zb_level, >=, 0);
 574 
 575         ASSERT(zb->zb_object == DMU_META_DNODE_OBJECT ||
 576             zb->zb_object >= dsa->dsa_resume_object);
 577 
 578         if (zb->zb_object != DMU_META_DNODE_OBJECT &&
 579             DMU_OBJECT_IS_SPECIAL(zb->zb_object)) {
 580                 return (0);
 581         } else if (BP_IS_HOLE(bp) &&
 582             zb->zb_object == DMU_META_DNODE_OBJECT) {
 583                 uint64_t span = BP_SPAN(dblkszsec, indblkshift, zb->zb_level);
 584                 uint64_t dnobj = (zb->zb_blkid * span) >> DNODE_SHIFT;
 585                 err = dump_freeobjects(dsa, dnobj, span >> DNODE_SHIFT);
 586         } else if (BP_IS_HOLE(bp)) {
 587                 uint64_t span = BP_SPAN(dblkszsec, indblkshift, zb->zb_level);
 588                 uint64_t offset = zb->zb_blkid * span;
 589                 err = dump_free(dsa, zb->zb_object, offset, span);
 590         } else if (zb->zb_level > 0 || type == DMU_OT_OBJSET) {
 591                 return (0);
 592         } else if (type == DMU_OT_DNODE) {
 593                 int blksz = BP_GET_LSIZE(bp);
 594                 arc_flags_t aflags = ARC_FLAG_WAIT;
 595                 arc_buf_t *abuf;
 596 
 597                 ASSERT0(zb->zb_level);
 598 
 599                 if (arc_read(NULL, spa, bp, arc_getbuf_func, &abuf,
 600                     ZIO_PRIORITY_ASYNC_READ, ZIO_FLAG_CANFAIL,
 601                     &aflags, zb) != 0)
 602                         return (SET_ERROR(EIO));
 603 
 604                 dnode_phys_t *blk = abuf->b_data;
 605                 uint64_t dnobj = zb->zb_blkid * (blksz >> DNODE_SHIFT);
 606                 for (int i = 0; i < blksz >> DNODE_SHIFT; i++) {
 607                         err = dump_dnode(dsa, dnobj + i, blk + i);
 608                         if (err != 0)
 609                                 break;
 610                 }
 611                 (void) arc_buf_remove_ref(abuf, &abuf);
 612         } else if (type == DMU_OT_SA) {
 613                 arc_flags_t aflags = ARC_FLAG_WAIT;
 614                 arc_buf_t *abuf;
 615                 int blksz = BP_GET_LSIZE(bp);
 616 
 617                 if (arc_read(NULL, spa, bp, arc_getbuf_func, &abuf,
 618                     ZIO_PRIORITY_ASYNC_READ, ZIO_FLAG_CANFAIL,
 619                     &aflags, zb) != 0)
 620                         return (SET_ERROR(EIO));
 621 
 622                 err = dump_spill(dsa, zb->zb_object, blksz, abuf->b_data);
 623                 (void) arc_buf_remove_ref(abuf, &abuf);
 624         } else if (backup_do_embed(dsa, bp)) {
 625                 /* it's an embedded level-0 block of a regular object */
 626                 int blksz = dblkszsec << SPA_MINBLOCKSHIFT;
 627                 ASSERT0(zb->zb_level);
 628                 err = dump_write_embedded(dsa, zb->zb_object,
 629                     zb->zb_blkid * blksz, blksz, bp);
 630         } else {
 631                 /* it's a level-0 block of a regular object */
 632                 arc_flags_t aflags = ARC_FLAG_WAIT;
 633                 arc_buf_t *abuf;
 634                 int blksz = dblkszsec << SPA_MINBLOCKSHIFT;
 635                 uint64_t offset;
 636 
 637                 ASSERT0(zb->zb_level);
 638                 ASSERT(zb->zb_object > dsa->dsa_resume_object ||
 639                     (zb->zb_object == dsa->dsa_resume_object &&
 640                     zb->zb_blkid * blksz >= dsa->dsa_resume_offset));
 641 
 642                 if (arc_read(NULL, spa, bp, arc_getbuf_func, &abuf,
 643                     ZIO_PRIORITY_ASYNC_READ, ZIO_FLAG_CANFAIL,
 644                     &aflags, zb) != 0) {
 645                         if (zfs_send_corrupt_data) {
 646                                 /* Send a block filled with 0x"zfs badd bloc" */
 647                                 abuf = arc_buf_alloc(spa, blksz, &abuf,
 648                                     ARC_BUFC_DATA);
 649                                 uint64_t *ptr;
 650                                 for (ptr = abuf->b_data;
 651                                     (char *)ptr < (char *)abuf->b_data + blksz;
 652                                     ptr++)
 653                                         *ptr = 0x2f5baddb10cULL;
 654                         } else {
 655                                 return (SET_ERROR(EIO));
 656                         }
 657                 }
 658 
 659                 offset = zb->zb_blkid * blksz;
 660 
 661                 if (!(dsa->dsa_featureflags &
 662                     DMU_BACKUP_FEATURE_LARGE_BLOCKS) &&
 663                     blksz > SPA_OLD_MAXBLOCKSIZE) {
 664                         char *buf = abuf->b_data;
 665                         while (blksz > 0 && err == 0) {
 666                                 int n = MIN(blksz, SPA_OLD_MAXBLOCKSIZE);
 667                                 err = dump_write(dsa, type, zb->zb_object,
 668                                     offset, n, NULL, buf);
 669                                 offset += n;
 670                                 buf += n;
 671                                 blksz -= n;
 672                         }
 673                 } else {
 674                         err = dump_write(dsa, type, zb->zb_object,
 675                             offset, blksz, bp, abuf->b_data);
 676                 }
 677                 (void) arc_buf_remove_ref(abuf, &abuf);
 678         }
 679 
 680         ASSERT(err == 0 || err == EINTR);
 681         return (err);
 682 }
 683 
 684 /*
 685  * Pop the new data off the queue, and free the old data.
 686  */
 687 static struct send_block_record *
 688 get_next_record(bqueue_t *bq, struct send_block_record *data)
 689 {
 690         struct send_block_record *tmp = bqueue_dequeue(bq);
 691         kmem_free(data, sizeof (*data));
 692         return (tmp);
 693 }
 694 
 695 /*
 696  * Actually do the bulk of the work in a zfs send.
 697  *
 698  * Note: Releases dp using the specified tag.
 699  */
 700 static int
 701 dmu_send_impl(void *tag, dsl_pool_t *dp, dsl_dataset_t *to_ds,
 702     zfs_bookmark_phys_t *ancestor_zb,
 703     boolean_t is_clone, boolean_t embedok, boolean_t large_block_ok, int outfd,
 704     uint64_t resumeobj, uint64_t resumeoff,
 705     vnode_t *vp, offset_t *off)
 706 {
 707         objset_t *os;
 708         dmu_replay_record_t *drr;
 709         dmu_sendarg_t *dsp;
 710         int err;
 711         uint64_t fromtxg = 0;
 712         uint64_t featureflags = 0;
 713         struct send_thread_arg to_arg = { 0 };
 714 
 715         err = dmu_objset_from_ds(to_ds, &os);
 716         if (err != 0) {
 717                 dsl_pool_rele(dp, tag);
 718                 return (err);
 719         }
 720 
 721         drr = kmem_zalloc(sizeof (dmu_replay_record_t), KM_SLEEP);
 722         drr->drr_type = DRR_BEGIN;
 723         drr->drr_u.drr_begin.drr_magic = DMU_BACKUP_MAGIC;
 724         DMU_SET_STREAM_HDRTYPE(drr->drr_u.drr_begin.drr_versioninfo,
 725             DMU_SUBSTREAM);
 726 
 727 #ifdef _KERNEL
 728         if (dmu_objset_type(os) == DMU_OST_ZFS) {
 729                 uint64_t version;
 730                 if (zfs_get_zplprop(os, ZFS_PROP_VERSION, &version) != 0) {
 731                         kmem_free(drr, sizeof (dmu_replay_record_t));
 732                         dsl_pool_rele(dp, tag);
 733                         return (SET_ERROR(EINVAL));
 734                 }
 735                 if (version >= ZPL_VERSION_SA) {
 736                         featureflags |= DMU_BACKUP_FEATURE_SA_SPILL;
 737                 }
 738         }
 739 #endif
 740 
 741         if (large_block_ok && to_ds->ds_feature_inuse[SPA_FEATURE_LARGE_BLOCKS])
 742                 featureflags |= DMU_BACKUP_FEATURE_LARGE_BLOCKS;
 743         if (embedok &&
 744             spa_feature_is_active(dp->dp_spa, SPA_FEATURE_EMBEDDED_DATA)) {
 745                 featureflags |= DMU_BACKUP_FEATURE_EMBED_DATA;
 746                 if (spa_feature_is_active(dp->dp_spa, SPA_FEATURE_LZ4_COMPRESS))
 747                         featureflags |= DMU_BACKUP_FEATURE_EMBED_DATA_LZ4;
 748         }
 749 
 750         if (resumeobj != 0 || resumeoff != 0) {
 751                 featureflags |= DMU_BACKUP_FEATURE_RESUMING;
 752         }
 753 
 754         DMU_SET_FEATUREFLAGS(drr->drr_u.drr_begin.drr_versioninfo,
 755             featureflags);
 756 
 757         drr->drr_u.drr_begin.drr_creation_time =
 758             dsl_dataset_phys(to_ds)->ds_creation_time;
 759         drr->drr_u.drr_begin.drr_type = dmu_objset_type(os);
 760         if (is_clone)
 761                 drr->drr_u.drr_begin.drr_flags |= DRR_FLAG_CLONE;
 762         drr->drr_u.drr_begin.drr_toguid = dsl_dataset_phys(to_ds)->ds_guid;
 763         if (dsl_dataset_phys(to_ds)->ds_flags & DS_FLAG_CI_DATASET)
 764                 drr->drr_u.drr_begin.drr_flags |= DRR_FLAG_CI_DATA;
 765         if (zfs_send_set_freerecords_bit)
 766                 drr->drr_u.drr_begin.drr_flags |= DRR_FLAG_FREERECORDS;
 767 
 768         if (ancestor_zb != NULL) {
 769                 drr->drr_u.drr_begin.drr_fromguid =
 770                     ancestor_zb->zbm_guid;
 771                 fromtxg = ancestor_zb->zbm_creation_txg;
 772         }
 773         dsl_dataset_name(to_ds, drr->drr_u.drr_begin.drr_toname);
 774         if (!to_ds->ds_is_snapshot) {
 775                 (void) strlcat(drr->drr_u.drr_begin.drr_toname, "@--head--",
 776                     sizeof (drr->drr_u.drr_begin.drr_toname));
 777         }
 778 
 779         dsp = kmem_zalloc(sizeof (dmu_sendarg_t), KM_SLEEP);
 780 
 781         dsp->dsa_drr = drr;
 782         dsp->dsa_vp = vp;
 783         dsp->dsa_outfd = outfd;
 784         dsp->dsa_proc = curproc;
 785         dsp->dsa_os = os;
 786         dsp->dsa_off = off;
 787         dsp->dsa_toguid = dsl_dataset_phys(to_ds)->ds_guid;
 788         dsp->dsa_pending_op = PENDING_NONE;
 789         dsp->dsa_featureflags = featureflags;
 790         dsp->dsa_resume_object = resumeobj;
 791         dsp->dsa_resume_offset = resumeoff;
 792 
 793         mutex_enter(&to_ds->ds_sendstream_lock);
 794         list_insert_head(&to_ds->ds_sendstreams, dsp);
 795         mutex_exit(&to_ds->ds_sendstream_lock);
 796 
 797         dsl_dataset_long_hold(to_ds, FTAG);
 798         dsl_pool_rele(dp, tag);
 799 
 800         void *payload = NULL;
 801         size_t payload_len = 0;
 802         if (resumeobj != 0 || resumeoff != 0) {
 803                 dmu_object_info_t to_doi;
 804                 err = dmu_object_info(os, resumeobj, &to_doi);
 805                 if (err != 0)
 806                         goto out;
 807                 SET_BOOKMARK(&to_arg.resume, to_ds->ds_object, resumeobj, 0,
 808                     resumeoff / to_doi.doi_data_block_size);
 809 
 810                 nvlist_t *nvl = fnvlist_alloc();
 811                 fnvlist_add_uint64(nvl, "resume_object", resumeobj);
 812                 fnvlist_add_uint64(nvl, "resume_offset", resumeoff);
 813                 payload = fnvlist_pack(nvl, &payload_len);
 814                 drr->drr_payloadlen = payload_len;
 815                 fnvlist_free(nvl);
 816         }
 817 
 818         err = dump_record(dsp, payload, payload_len);
 819         fnvlist_pack_free(payload, payload_len);
 820         if (err != 0) {
 821                 err = dsp->dsa_err;
 822                 goto out;
 823         }
 824 
 825         err = bqueue_init(&to_arg.q, zfs_send_queue_length,
 826             offsetof(struct send_block_record, ln));
 827         to_arg.error_code = 0;
 828         to_arg.cancel = B_FALSE;
 829         to_arg.ds = to_ds;
 830         to_arg.fromtxg = fromtxg;
 831         to_arg.flags = TRAVERSE_PRE | TRAVERSE_PREFETCH;
 832         (void) thread_create(NULL, 0, send_traverse_thread, &to_arg, 0, curproc,
 833             TS_RUN, minclsyspri);
 834 
 835         struct send_block_record *to_data;
 836         to_data = bqueue_dequeue(&to_arg.q);
 837 
 838         while (!to_data->eos_marker && err == 0) {
 839                 err = do_dump(dsp, to_data);
 840                 to_data = get_next_record(&to_arg.q, to_data);
 841                 if (issig(JUSTLOOKING) && issig(FORREAL))
 842                         err = EINTR;
 843         }
 844 
 845         if (err != 0) {
 846                 to_arg.cancel = B_TRUE;
 847                 while (!to_data->eos_marker) {
 848                         to_data = get_next_record(&to_arg.q, to_data);
 849                 }
 850         }
 851         kmem_free(to_data, sizeof (*to_data));
 852 
 853         bqueue_destroy(&to_arg.q);
 854 
 855         if (err == 0 && to_arg.error_code != 0)
 856                 err = to_arg.error_code;
 857 
 858         if (err != 0)
 859                 goto out;
 860 
 861         if (dsp->dsa_pending_op != PENDING_NONE)
 862                 if (dump_record(dsp, NULL, 0) != 0)
 863                         err = SET_ERROR(EINTR);
 864 
 865         if (err != 0) {
 866                 if (err == EINTR && dsp->dsa_err != 0)
 867                         err = dsp->dsa_err;
 868                 goto out;
 869         }
 870 
 871         bzero(drr, sizeof (dmu_replay_record_t));
 872         drr->drr_type = DRR_END;
 873         drr->drr_u.drr_end.drr_checksum = dsp->dsa_zc;
 874         drr->drr_u.drr_end.drr_toguid = dsp->dsa_toguid;
 875 
 876         if (dump_record(dsp, NULL, 0) != 0)
 877                 err = dsp->dsa_err;
 878 
 879 out:
 880         mutex_enter(&to_ds->ds_sendstream_lock);
 881         list_remove(&to_ds->ds_sendstreams, dsp);
 882         mutex_exit(&to_ds->ds_sendstream_lock);
 883 
 884         kmem_free(drr, sizeof (dmu_replay_record_t));
 885         kmem_free(dsp, sizeof (dmu_sendarg_t));
 886 
 887         dsl_dataset_long_rele(to_ds, FTAG);
 888 
 889         return (err);
 890 }
 891 
 892 int
 893 dmu_send_obj(const char *pool, uint64_t tosnap, uint64_t fromsnap,
 894     boolean_t embedok, boolean_t large_block_ok,
 895     int outfd, vnode_t *vp, offset_t *off)
 896 {
 897         dsl_pool_t *dp;
 898         dsl_dataset_t *ds;
 899         dsl_dataset_t *fromds = NULL;
 900         int err;
 901 
 902         err = dsl_pool_hold(pool, FTAG, &dp);
 903         if (err != 0)
 904                 return (err);
 905 
 906         err = dsl_dataset_hold_obj(dp, tosnap, FTAG, &ds);
 907         if (err != 0) {
 908                 dsl_pool_rele(dp, FTAG);
 909                 return (err);
 910         }
 911 
 912         if (fromsnap != 0) {
 913                 zfs_bookmark_phys_t zb;
 914                 boolean_t is_clone;
 915 
 916                 err = dsl_dataset_hold_obj(dp, fromsnap, FTAG, &fromds);
 917                 if (err != 0) {
 918                         dsl_dataset_rele(ds, FTAG);
 919                         dsl_pool_rele(dp, FTAG);
 920                         return (err);
 921                 }
 922                 if (!dsl_dataset_is_before(ds, fromds, 0))
 923                         err = SET_ERROR(EXDEV);
 924                 zb.zbm_creation_time =
 925                     dsl_dataset_phys(fromds)->ds_creation_time;
 926                 zb.zbm_creation_txg = dsl_dataset_phys(fromds)->ds_creation_txg;
 927                 zb.zbm_guid = dsl_dataset_phys(fromds)->ds_guid;
 928                 is_clone = (fromds->ds_dir != ds->ds_dir);
 929                 dsl_dataset_rele(fromds, FTAG);
 930                 err = dmu_send_impl(FTAG, dp, ds, &zb, is_clone,
 931                     embedok, large_block_ok, outfd, 0, 0, vp, off);
 932         } else {
 933                 err = dmu_send_impl(FTAG, dp, ds, NULL, B_FALSE,
 934                     embedok, large_block_ok, outfd, 0, 0, vp, off);
 935         }
 936         dsl_dataset_rele(ds, FTAG);
 937         return (err);
 938 }
 939 
 940 int
 941 dmu_send(const char *tosnap, const char *fromsnap, boolean_t embedok,
 942     boolean_t large_block_ok, int outfd, uint64_t resumeobj, uint64_t resumeoff,
 943     vnode_t *vp, offset_t *off)
 944 {
 945         dsl_pool_t *dp;
 946         dsl_dataset_t *ds;
 947         int err;
 948         boolean_t owned = B_FALSE;
 949 
 950         if (fromsnap != NULL && strpbrk(fromsnap, "@#") == NULL)
 951                 return (SET_ERROR(EINVAL));
 952 
 953         err = dsl_pool_hold(tosnap, FTAG, &dp);
 954         if (err != 0)
 955                 return (err);
 956 
 957         if (strchr(tosnap, '@') == NULL && spa_writeable(dp->dp_spa)) {
 958                 /*
 959                  * We are sending a filesystem or volume.  Ensure
 960                  * that it doesn't change by owning the dataset.
 961                  */
 962                 err = dsl_dataset_own(dp, tosnap, FTAG, &ds);
 963                 owned = B_TRUE;
 964         } else {
 965                 err = dsl_dataset_hold(dp, tosnap, FTAG, &ds);
 966         }
 967         if (err != 0) {
 968                 dsl_pool_rele(dp, FTAG);
 969                 return (err);
 970         }
 971 
 972         if (fromsnap != NULL) {
 973                 zfs_bookmark_phys_t zb;
 974                 boolean_t is_clone = B_FALSE;
 975                 int fsnamelen = strchr(tosnap, '@') - tosnap;
 976 
 977                 /*
 978                  * If the fromsnap is in a different filesystem, then
 979                  * mark the send stream as a clone.
 980                  */
 981                 if (strncmp(tosnap, fromsnap, fsnamelen) != 0 ||
 982                     (fromsnap[fsnamelen] != '@' &&
 983                     fromsnap[fsnamelen] != '#')) {
 984                         is_clone = B_TRUE;
 985                 }
 986 
 987                 if (strchr(fromsnap, '@')) {
 988                         dsl_dataset_t *fromds;
 989                         err = dsl_dataset_hold(dp, fromsnap, FTAG, &fromds);
 990                         if (err == 0) {
 991                                 if (!dsl_dataset_is_before(ds, fromds, 0))
 992                                         err = SET_ERROR(EXDEV);
 993                                 zb.zbm_creation_time =
 994                                     dsl_dataset_phys(fromds)->ds_creation_time;
 995                                 zb.zbm_creation_txg =
 996                                     dsl_dataset_phys(fromds)->ds_creation_txg;
 997                                 zb.zbm_guid = dsl_dataset_phys(fromds)->ds_guid;
 998                                 is_clone = (ds->ds_dir != fromds->ds_dir);
 999                                 dsl_dataset_rele(fromds, FTAG);
1000                         }
1001                 } else {
1002                         err = dsl_bookmark_lookup(dp, fromsnap, ds, &zb);
1003                 }
1004                 if (err != 0) {
1005                         dsl_dataset_rele(ds, FTAG);
1006                         dsl_pool_rele(dp, FTAG);
1007                         return (err);
1008                 }
1009                 err = dmu_send_impl(FTAG, dp, ds, &zb, is_clone,
1010                     embedok, large_block_ok,
1011                     outfd, resumeobj, resumeoff, vp, off);
1012         } else {
1013                 err = dmu_send_impl(FTAG, dp, ds, NULL, B_FALSE,
1014                     embedok, large_block_ok,
1015                     outfd, resumeobj, resumeoff, vp, off);
1016         }
1017         if (owned)
1018                 dsl_dataset_disown(ds, FTAG);
1019         else
1020                 dsl_dataset_rele(ds, FTAG);
1021         return (err);
1022 }
1023 
1024 static int
1025 dmu_adjust_send_estimate_for_indirects(dsl_dataset_t *ds, uint64_t size,
1026     uint64_t *sizep)
1027 {
1028         int err;
1029         /*
1030          * Assume that space (both on-disk and in-stream) is dominated by
1031          * data.  We will adjust for indirect blocks and the copies property,
1032          * but ignore per-object space used (eg, dnodes and DRR_OBJECT records).
1033          */
1034 
1035         /*
1036          * Subtract out approximate space used by indirect blocks.
1037          * Assume most space is used by data blocks (non-indirect, non-dnode).
1038          * Assume all blocks are recordsize.  Assume ditto blocks and
1039          * internal fragmentation counter out compression.
1040          *
1041          * Therefore, space used by indirect blocks is sizeof(blkptr_t) per
1042          * block, which we observe in practice.
1043          */
1044         uint64_t recordsize;
1045         err = dsl_prop_get_int_ds(ds, "recordsize", &recordsize);
1046         if (err != 0)
1047                 return (err);
1048         size -= size / recordsize * sizeof (blkptr_t);
1049 
1050         /* Add in the space for the record associated with each block. */
1051         size += size / recordsize * sizeof (dmu_replay_record_t);
1052 
1053         *sizep = size;
1054 
1055         return (0);
1056 }
1057 
1058 int
1059 dmu_send_estimate(dsl_dataset_t *ds, dsl_dataset_t *fromds, uint64_t *sizep)
1060 {
1061         dsl_pool_t *dp = ds->ds_dir->dd_pool;
1062         int err;
1063         uint64_t size;
1064 
1065         ASSERT(dsl_pool_config_held(dp));
1066 
1067         /* tosnap must be a snapshot */
1068         if (!ds->ds_is_snapshot)
1069                 return (SET_ERROR(EINVAL));
1070 
1071         /* fromsnap, if provided, must be a snapshot */
1072         if (fromds != NULL && !fromds->ds_is_snapshot)
1073                 return (SET_ERROR(EINVAL));
1074 
1075         /*
1076          * fromsnap must be an earlier snapshot from the same fs as tosnap,
1077          * or the origin's fs.
1078          */
1079         if (fromds != NULL && !dsl_dataset_is_before(ds, fromds, 0))
1080                 return (SET_ERROR(EXDEV));
1081 
1082         /* Get uncompressed size estimate of changed data. */
1083         if (fromds == NULL) {
1084                 size = dsl_dataset_phys(ds)->ds_uncompressed_bytes;
1085         } else {
1086                 uint64_t used, comp;
1087                 err = dsl_dataset_space_written(fromds, ds,
1088                     &used, &comp, &size);
1089                 if (err != 0)
1090                         return (err);
1091         }
1092 
1093         err = dmu_adjust_send_estimate_for_indirects(ds, size, sizep);
1094         return (err);
1095 }
1096 
1097 /*
1098  * Simple callback used to traverse the blocks of a snapshot and sum their
1099  * uncompressed size
1100  */
1101 /* ARGSUSED */
1102 static int
1103 dmu_calculate_send_traversal(spa_t *spa, zilog_t *zilog, const blkptr_t *bp,
1104     const zbookmark_phys_t *zb, const dnode_phys_t *dnp, void *arg)
1105 {
1106         uint64_t *spaceptr = arg;
1107         if (bp != NULL && !BP_IS_HOLE(bp)) {
1108                 *spaceptr += BP_GET_UCSIZE(bp);
1109         }
1110         return (0);
1111 }
1112 
1113 /*
1114  * Given a desination snapshot and a TXG, calculate the approximate size of a
1115  * send stream sent from that TXG. from_txg may be zero, indicating that the
1116  * whole snapshot will be sent.
1117  */
1118 int
1119 dmu_send_estimate_from_txg(dsl_dataset_t *ds, uint64_t from_txg,
1120     uint64_t *sizep)
1121 {
1122         dsl_pool_t *dp = ds->ds_dir->dd_pool;
1123         int err;
1124         uint64_t size = 0;
1125 
1126         ASSERT(dsl_pool_config_held(dp));
1127 
1128         /* tosnap must be a snapshot */
1129         if (!dsl_dataset_is_snapshot(ds))
1130                 return (SET_ERROR(EINVAL));
1131 
1132         /* verify that from_txg is before the provided snapshot was taken */
1133         if (from_txg >= dsl_dataset_phys(ds)->ds_creation_txg) {
1134                 return (SET_ERROR(EXDEV));
1135         }
1136 
1137         /*
1138          * traverse the blocks of the snapshot with birth times after
1139          * from_txg, summing their uncompressed size
1140          */
1141         err = traverse_dataset(ds, from_txg, TRAVERSE_POST,
1142             dmu_calculate_send_traversal, &size);
1143         if (err)
1144                 return (err);
1145 
1146         err = dmu_adjust_send_estimate_for_indirects(ds, size, sizep);
1147         return (err);
1148 }
1149 
1150 typedef struct dmu_recv_begin_arg {
1151         const char *drba_origin;
1152         dmu_recv_cookie_t *drba_cookie;
1153         cred_t *drba_cred;
1154         uint64_t drba_snapobj;
1155 } dmu_recv_begin_arg_t;
1156 
1157 static int
1158 recv_begin_check_existing_impl(dmu_recv_begin_arg_t *drba, dsl_dataset_t *ds,
1159     uint64_t fromguid)
1160 {
1161         uint64_t val;
1162         int error;
1163         dsl_pool_t *dp = ds->ds_dir->dd_pool;
1164 
1165         /* temporary clone name must not exist */
1166         error = zap_lookup(dp->dp_meta_objset,
1167             dsl_dir_phys(ds->ds_dir)->dd_child_dir_zapobj, recv_clone_name,
1168             8, 1, &val);
1169         if (error != ENOENT)
1170                 return (error == 0 ? EBUSY : error);
1171 
1172         /* new snapshot name must not exist */
1173         error = zap_lookup(dp->dp_meta_objset,
1174             dsl_dataset_phys(ds)->ds_snapnames_zapobj,
1175             drba->drba_cookie->drc_tosnap, 8, 1, &val);
1176         if (error != ENOENT)
1177                 return (error == 0 ? EEXIST : error);
1178 
1179         /*
1180          * Check snapshot limit before receiving. We'll recheck again at the
1181          * end, but might as well abort before receiving if we're already over
1182          * the limit.
1183          *
1184          * Note that we do not check the file system limit with
1185          * dsl_dir_fscount_check because the temporary %clones don't count
1186          * against that limit.
1187          */
1188         error = dsl_fs_ss_limit_check(ds->ds_dir, 1, ZFS_PROP_SNAPSHOT_LIMIT,
1189             NULL, drba->drba_cred);
1190         if (error != 0)
1191                 return (error);
1192 
1193         if (fromguid != 0) {
1194                 dsl_dataset_t *snap;
1195                 uint64_t obj = dsl_dataset_phys(ds)->ds_prev_snap_obj;
1196 
1197                 /* Find snapshot in this dir that matches fromguid. */
1198                 while (obj != 0) {
1199                         error = dsl_dataset_hold_obj(dp, obj, FTAG,
1200                             &snap);
1201                         if (error != 0)
1202                                 return (SET_ERROR(ENODEV));
1203                         if (snap->ds_dir != ds->ds_dir) {
1204                                 dsl_dataset_rele(snap, FTAG);
1205                                 return (SET_ERROR(ENODEV));
1206                         }
1207                         if (dsl_dataset_phys(snap)->ds_guid == fromguid)
1208                                 break;
1209                         obj = dsl_dataset_phys(snap)->ds_prev_snap_obj;
1210                         dsl_dataset_rele(snap, FTAG);
1211                 }
1212                 if (obj == 0)
1213                         return (SET_ERROR(ENODEV));
1214 
1215                 if (drba->drba_cookie->drc_force) {
1216                         drba->drba_snapobj = obj;
1217                 } else {
1218                         /*
1219                          * If we are not forcing, there must be no
1220                          * changes since fromsnap.
1221                          */
1222                         if (dsl_dataset_modified_since_snap(ds, snap)) {
1223                                 dsl_dataset_rele(snap, FTAG);
1224                                 return (SET_ERROR(ETXTBSY));
1225                         }
1226                         drba->drba_snapobj = ds->ds_prev->ds_object;
1227                 }
1228 
1229                 dsl_dataset_rele(snap, FTAG);
1230         } else {
1231                 /* if full, then must be forced */
1232                 if (!drba->drba_cookie->drc_force)
1233                         return (SET_ERROR(EEXIST));
1234                 /* start from $ORIGIN@$ORIGIN, if supported */
1235                 drba->drba_snapobj = dp->dp_origin_snap != NULL ?
1236                     dp->dp_origin_snap->ds_object : 0;
1237         }
1238 
1239         return (0);
1240 
1241 }
1242 
1243 static int
1244 dmu_recv_begin_check(void *arg, dmu_tx_t *tx)
1245 {
1246         dmu_recv_begin_arg_t *drba = arg;
1247         dsl_pool_t *dp = dmu_tx_pool(tx);
1248         struct drr_begin *drrb = drba->drba_cookie->drc_drrb;
1249         uint64_t fromguid = drrb->drr_fromguid;
1250         int flags = drrb->drr_flags;
1251         int error;
1252         uint64_t featureflags = DMU_GET_FEATUREFLAGS(drrb->drr_versioninfo);
1253         dsl_dataset_t *ds;
1254         const char *tofs = drba->drba_cookie->drc_tofs;
1255 
1256         /* already checked */
1257         ASSERT3U(drrb->drr_magic, ==, DMU_BACKUP_MAGIC);
1258         ASSERT(!(featureflags & DMU_BACKUP_FEATURE_RESUMING));
1259 
1260         if (DMU_GET_STREAM_HDRTYPE(drrb->drr_versioninfo) ==
1261             DMU_COMPOUNDSTREAM ||
1262             drrb->drr_type >= DMU_OST_NUMTYPES ||
1263             ((flags & DRR_FLAG_CLONE) && drba->drba_origin == NULL))
1264                 return (SET_ERROR(EINVAL));
1265 
1266         /* Verify pool version supports SA if SA_SPILL feature set */
1267         if ((featureflags & DMU_BACKUP_FEATURE_SA_SPILL) &&
1268             spa_version(dp->dp_spa) < SPA_VERSION_SA)
1269                 return (SET_ERROR(ENOTSUP));
1270 
1271         if (drba->drba_cookie->drc_resumable &&
1272             !spa_feature_is_enabled(dp->dp_spa, SPA_FEATURE_EXTENSIBLE_DATASET))
1273                 return (SET_ERROR(ENOTSUP));
1274 
1275         /*
1276          * The receiving code doesn't know how to translate a WRITE_EMBEDDED
1277          * record to a plan WRITE record, so the pool must have the
1278          * EMBEDDED_DATA feature enabled if the stream has WRITE_EMBEDDED
1279          * records.  Same with WRITE_EMBEDDED records that use LZ4 compression.
1280          */
1281         if ((featureflags & DMU_BACKUP_FEATURE_EMBED_DATA) &&
1282             !spa_feature_is_enabled(dp->dp_spa, SPA_FEATURE_EMBEDDED_DATA))
1283                 return (SET_ERROR(ENOTSUP));
1284         if ((featureflags & DMU_BACKUP_FEATURE_EMBED_DATA_LZ4) &&
1285             !spa_feature_is_enabled(dp->dp_spa, SPA_FEATURE_LZ4_COMPRESS))
1286                 return (SET_ERROR(ENOTSUP));
1287 
1288         /*
1289          * The receiving code doesn't know how to translate large blocks
1290          * to smaller ones, so the pool must have the LARGE_BLOCKS
1291          * feature enabled if the stream has LARGE_BLOCKS.
1292          */
1293         if ((featureflags & DMU_BACKUP_FEATURE_LARGE_BLOCKS) &&
1294             !spa_feature_is_enabled(dp->dp_spa, SPA_FEATURE_LARGE_BLOCKS))
1295                 return (SET_ERROR(ENOTSUP));
1296 
1297         error = dsl_dataset_hold(dp, tofs, FTAG, &ds);
1298         if (error == 0) {
1299                 /* target fs already exists; recv into temp clone */
1300 
1301                 /* Can't recv a clone into an existing fs */
1302                 if (flags & DRR_FLAG_CLONE || drba->drba_origin) {
1303                         dsl_dataset_rele(ds, FTAG);
1304                         return (SET_ERROR(EINVAL));
1305                 }
1306 
1307                 error = recv_begin_check_existing_impl(drba, ds, fromguid);
1308                 dsl_dataset_rele(ds, FTAG);
1309         } else if (error == ENOENT) {
1310                 /* target fs does not exist; must be a full backup or clone */
1311                 char buf[ZFS_MAX_DATASET_NAME_LEN];
1312 
1313                 /*
1314                  * If it's a non-clone incremental, we are missing the
1315                  * target fs, so fail the recv.
1316                  */
1317                 if (fromguid != 0 && !(flags & DRR_FLAG_CLONE ||
1318                     drba->drba_origin))
1319                         return (SET_ERROR(ENOENT));
1320 
1321                 /*
1322                  * If we're receiving a full send as a clone, and it doesn't
1323                  * contain all the necessary free records and freeobject
1324                  * records, reject it.
1325                  */
1326                 if (fromguid == 0 && drba->drba_origin &&
1327                     !(flags & DRR_FLAG_FREERECORDS))
1328                         return (SET_ERROR(EINVAL));
1329 
1330                 /* Open the parent of tofs */
1331                 ASSERT3U(strlen(tofs), <, sizeof (buf));
1332                 (void) strlcpy(buf, tofs, strrchr(tofs, '/') - tofs + 1);
1333                 error = dsl_dataset_hold(dp, buf, FTAG, &ds);
1334                 if (error != 0)
1335                         return (error);
1336 
1337                 /*
1338                  * Check filesystem and snapshot limits before receiving. We'll
1339                  * recheck snapshot limits again at the end (we create the
1340                  * filesystems and increment those counts during begin_sync).
1341                  */
1342                 error = dsl_fs_ss_limit_check(ds->ds_dir, 1,
1343                     ZFS_PROP_FILESYSTEM_LIMIT, NULL, drba->drba_cred);
1344                 if (error != 0) {
1345                         dsl_dataset_rele(ds, FTAG);
1346                         return (error);
1347                 }
1348 
1349                 error = dsl_fs_ss_limit_check(ds->ds_dir, 1,
1350                     ZFS_PROP_SNAPSHOT_LIMIT, NULL, drba->drba_cred);
1351                 if (error != 0) {
1352                         dsl_dataset_rele(ds, FTAG);
1353                         return (error);
1354                 }
1355 
1356                 if (drba->drba_origin != NULL) {
1357                         dsl_dataset_t *origin;
1358                         error = dsl_dataset_hold(dp, drba->drba_origin,
1359                             FTAG, &origin);
1360                         if (error != 0) {
1361                                 dsl_dataset_rele(ds, FTAG);
1362                                 return (error);
1363                         }
1364                         if (!origin->ds_is_snapshot) {
1365                                 dsl_dataset_rele(origin, FTAG);
1366                                 dsl_dataset_rele(ds, FTAG);
1367                                 return (SET_ERROR(EINVAL));
1368                         }
1369                         if (dsl_dataset_phys(origin)->ds_guid != fromguid &&
1370                             fromguid != 0) {
1371                                 dsl_dataset_rele(origin, FTAG);
1372                                 dsl_dataset_rele(ds, FTAG);
1373                                 return (SET_ERROR(ENODEV));
1374                         }
1375                         dsl_dataset_rele(origin, FTAG);
1376                 }
1377                 dsl_dataset_rele(ds, FTAG);
1378                 error = 0;
1379         }
1380         return (error);
1381 }
1382 
1383 static void
1384 dmu_recv_begin_sync(void *arg, dmu_tx_t *tx)
1385 {
1386         dmu_recv_begin_arg_t *drba = arg;
1387         dsl_pool_t *dp = dmu_tx_pool(tx);
1388         objset_t *mos = dp->dp_meta_objset;
1389         struct drr_begin *drrb = drba->drba_cookie->drc_drrb;
1390         const char *tofs = drba->drba_cookie->drc_tofs;
1391         dsl_dataset_t *ds, *newds;
1392         uint64_t dsobj;
1393         int error;
1394         uint64_t crflags = 0;
1395 
1396         if (drrb->drr_flags & DRR_FLAG_CI_DATA)
1397                 crflags |= DS_FLAG_CI_DATASET;
1398 
1399         error = dsl_dataset_hold(dp, tofs, FTAG, &ds);
1400         if (error == 0) {
1401                 /* create temporary clone */
1402                 dsl_dataset_t *snap = NULL;
1403                 if (drba->drba_snapobj != 0) {
1404                         VERIFY0(dsl_dataset_hold_obj(dp,
1405                             drba->drba_snapobj, FTAG, &snap));
1406                 }
1407                 dsobj = dsl_dataset_create_sync(ds->ds_dir, recv_clone_name,
1408                     snap, crflags, drba->drba_cred, tx);
1409                 if (drba->drba_snapobj != 0)
1410                         dsl_dataset_rele(snap, FTAG);
1411                 dsl_dataset_rele(ds, FTAG);
1412         } else {
1413                 dsl_dir_t *dd;
1414                 const char *tail;
1415                 dsl_dataset_t *origin = NULL;
1416 
1417                 VERIFY0(dsl_dir_hold(dp, tofs, FTAG, &dd, &tail));
1418 
1419                 if (drba->drba_origin != NULL) {
1420                         VERIFY0(dsl_dataset_hold(dp, drba->drba_origin,
1421                             FTAG, &origin));
1422                 }
1423 
1424                 /* Create new dataset. */
1425                 dsobj = dsl_dataset_create_sync(dd,
1426                     strrchr(tofs, '/') + 1,
1427                     origin, crflags, drba->drba_cred, tx);
1428                 if (origin != NULL)
1429                         dsl_dataset_rele(origin, FTAG);
1430                 dsl_dir_rele(dd, FTAG);
1431                 drba->drba_cookie->drc_newfs = B_TRUE;
1432         }
1433         VERIFY0(dsl_dataset_own_obj(dp, dsobj, dmu_recv_tag, &newds));
1434 
1435         if (drba->drba_cookie->drc_resumable) {
1436                 dsl_dataset_zapify(newds, tx);
1437                 if (drrb->drr_fromguid != 0) {
1438                         VERIFY0(zap_add(mos, dsobj, DS_FIELD_RESUME_FROMGUID,
1439                             8, 1, &drrb->drr_fromguid, tx));
1440                 }
1441                 VERIFY0(zap_add(mos, dsobj, DS_FIELD_RESUME_TOGUID,
1442                     8, 1, &drrb->drr_toguid, tx));
1443                 VERIFY0(zap_add(mos, dsobj, DS_FIELD_RESUME_TONAME,
1444                     1, strlen(drrb->drr_toname) + 1, drrb->drr_toname, tx));
1445                 uint64_t one = 1;
1446                 uint64_t zero = 0;
1447                 VERIFY0(zap_add(mos, dsobj, DS_FIELD_RESUME_OBJECT,
1448                     8, 1, &one, tx));
1449                 VERIFY0(zap_add(mos, dsobj, DS_FIELD_RESUME_OFFSET,
1450                     8, 1, &zero, tx));
1451                 VERIFY0(zap_add(mos, dsobj, DS_FIELD_RESUME_BYTES,
1452                     8, 1, &zero, tx));
1453                 if (DMU_GET_FEATUREFLAGS(drrb->drr_versioninfo) &
1454                     DMU_BACKUP_FEATURE_EMBED_DATA) {
1455                         VERIFY0(zap_add(mos, dsobj, DS_FIELD_RESUME_EMBEDOK,
1456                             8, 1, &one, tx));
1457                 }
1458         }
1459 
1460         dmu_buf_will_dirty(newds->ds_dbuf, tx);
1461         dsl_dataset_phys(newds)->ds_flags |= DS_FLAG_INCONSISTENT;
1462 
1463         /*
1464          * If we actually created a non-clone, we need to create the
1465          * objset in our new dataset.
1466          */
1467         if (BP_IS_HOLE(dsl_dataset_get_blkptr(newds))) {
1468                 (void) dmu_objset_create_impl(dp->dp_spa,
1469                     newds, dsl_dataset_get_blkptr(newds), drrb->drr_type, tx);
1470         }
1471 
1472         drba->drba_cookie->drc_ds = newds;
1473 
1474         spa_history_log_internal_ds(newds, "receive", tx, "");
1475 }
1476 
1477 static int
1478 dmu_recv_resume_begin_check(void *arg, dmu_tx_t *tx)
1479 {
1480         dmu_recv_begin_arg_t *drba = arg;
1481         dsl_pool_t *dp = dmu_tx_pool(tx);
1482         struct drr_begin *drrb = drba->drba_cookie->drc_drrb;
1483         int error;
1484         uint64_t featureflags = DMU_GET_FEATUREFLAGS(drrb->drr_versioninfo);
1485         dsl_dataset_t *ds;
1486         const char *tofs = drba->drba_cookie->drc_tofs;
1487 
1488         /* already checked */
1489         ASSERT3U(drrb->drr_magic, ==, DMU_BACKUP_MAGIC);
1490         ASSERT(featureflags & DMU_BACKUP_FEATURE_RESUMING);
1491 
1492         if (DMU_GET_STREAM_HDRTYPE(drrb->drr_versioninfo) ==
1493             DMU_COMPOUNDSTREAM ||
1494             drrb->drr_type >= DMU_OST_NUMTYPES)
1495                 return (SET_ERROR(EINVAL));
1496 
1497         /* Verify pool version supports SA if SA_SPILL feature set */
1498         if ((featureflags & DMU_BACKUP_FEATURE_SA_SPILL) &&
1499             spa_version(dp->dp_spa) < SPA_VERSION_SA)
1500                 return (SET_ERROR(ENOTSUP));
1501 
1502         /*
1503          * The receiving code doesn't know how to translate a WRITE_EMBEDDED
1504          * record to a plain WRITE record, so the pool must have the
1505          * EMBEDDED_DATA feature enabled if the stream has WRITE_EMBEDDED
1506          * records.  Same with WRITE_EMBEDDED records that use LZ4 compression.
1507          */
1508         if ((featureflags & DMU_BACKUP_FEATURE_EMBED_DATA) &&
1509             !spa_feature_is_enabled(dp->dp_spa, SPA_FEATURE_EMBEDDED_DATA))
1510                 return (SET_ERROR(ENOTSUP));
1511         if ((featureflags & DMU_BACKUP_FEATURE_EMBED_DATA_LZ4) &&
1512             !spa_feature_is_enabled(dp->dp_spa, SPA_FEATURE_LZ4_COMPRESS))
1513                 return (SET_ERROR(ENOTSUP));
1514 
1515         /* 6 extra bytes for /%recv */
1516         char recvname[ZFS_MAX_DATASET_NAME_LEN + 6];
1517 
1518         (void) snprintf(recvname, sizeof (recvname), "%s/%s",
1519             tofs, recv_clone_name);
1520 
1521         if (dsl_dataset_hold(dp, recvname, FTAG, &ds) != 0) {
1522                 /* %recv does not exist; continue in tofs */
1523                 error = dsl_dataset_hold(dp, tofs, FTAG, &ds);
1524                 if (error != 0)
1525                         return (error);
1526         }
1527 
1528         /* check that ds is marked inconsistent */
1529         if (!DS_IS_INCONSISTENT(ds)) {
1530                 dsl_dataset_rele(ds, FTAG);
1531                 return (SET_ERROR(EINVAL));
1532         }
1533 
1534         /* check that there is resuming data, and that the toguid matches */
1535         if (!dsl_dataset_is_zapified(ds)) {
1536                 dsl_dataset_rele(ds, FTAG);
1537                 return (SET_ERROR(EINVAL));
1538         }
1539         uint64_t val;
1540         error = zap_lookup(dp->dp_meta_objset, ds->ds_object,
1541             DS_FIELD_RESUME_TOGUID, sizeof (val), 1, &val);
1542         if (error != 0 || drrb->drr_toguid != val) {
1543                 dsl_dataset_rele(ds, FTAG);
1544                 return (SET_ERROR(EINVAL));
1545         }
1546 
1547         /*
1548          * Check if the receive is still running.  If so, it will be owned.
1549          * Note that nothing else can own the dataset (e.g. after the receive
1550          * fails) because it will be marked inconsistent.
1551          */
1552         if (dsl_dataset_has_owner(ds)) {
1553                 dsl_dataset_rele(ds, FTAG);
1554                 return (SET_ERROR(EBUSY));
1555         }
1556 
1557         /* There should not be any snapshots of this fs yet. */
1558         if (ds->ds_prev != NULL && ds->ds_prev->ds_dir == ds->ds_dir) {
1559                 dsl_dataset_rele(ds, FTAG);
1560                 return (SET_ERROR(EINVAL));
1561         }
1562 
1563         /*
1564          * Note: resume point will be checked when we process the first WRITE
1565          * record.
1566          */
1567 
1568         /* check that the origin matches */
1569         val = 0;
1570         (void) zap_lookup(dp->dp_meta_objset, ds->ds_object,
1571             DS_FIELD_RESUME_FROMGUID, sizeof (val), 1, &val);
1572         if (drrb->drr_fromguid != val) {
1573                 dsl_dataset_rele(ds, FTAG);
1574                 return (SET_ERROR(EINVAL));
1575         }
1576 
1577         dsl_dataset_rele(ds, FTAG);
1578         return (0);
1579 }
1580 
1581 static void
1582 dmu_recv_resume_begin_sync(void *arg, dmu_tx_t *tx)
1583 {
1584         dmu_recv_begin_arg_t *drba = arg;
1585         dsl_pool_t *dp = dmu_tx_pool(tx);
1586         const char *tofs = drba->drba_cookie->drc_tofs;
1587         dsl_dataset_t *ds;
1588         uint64_t dsobj;
1589         /* 6 extra bytes for /%recv */
1590         char recvname[ZFS_MAX_DATASET_NAME_LEN + 6];
1591 
1592         (void) snprintf(recvname, sizeof (recvname), "%s/%s",
1593             tofs, recv_clone_name);
1594 
1595         if (dsl_dataset_hold(dp, recvname, FTAG, &ds) != 0) {
1596                 /* %recv does not exist; continue in tofs */
1597                 VERIFY0(dsl_dataset_hold(dp, tofs, FTAG, &ds));
1598                 drba->drba_cookie->drc_newfs = B_TRUE;
1599         }
1600 
1601         /* clear the inconsistent flag so that we can own it */
1602         ASSERT(DS_IS_INCONSISTENT(ds));
1603         dmu_buf_will_dirty(ds->ds_dbuf, tx);
1604         dsl_dataset_phys(ds)->ds_flags &= ~DS_FLAG_INCONSISTENT;
1605         dsobj = ds->ds_object;
1606         dsl_dataset_rele(ds, FTAG);
1607 
1608         VERIFY0(dsl_dataset_own_obj(dp, dsobj, dmu_recv_tag, &ds));
1609 
1610         dmu_buf_will_dirty(ds->ds_dbuf, tx);
1611         dsl_dataset_phys(ds)->ds_flags |= DS_FLAG_INCONSISTENT;
1612 
1613         ASSERT(!BP_IS_HOLE(dsl_dataset_get_blkptr(ds)));
1614 
1615         drba->drba_cookie->drc_ds = ds;
1616 
1617         spa_history_log_internal_ds(ds, "resume receive", tx, "");
1618 }
1619 
1620 /*
1621  * NB: callers *MUST* call dmu_recv_stream() if dmu_recv_begin()
1622  * succeeds; otherwise we will leak the holds on the datasets.
1623  */
1624 int
1625 dmu_recv_begin(char *tofs, char *tosnap, dmu_replay_record_t *drr_begin,
1626     boolean_t force, boolean_t resumable, char *origin, dmu_recv_cookie_t *drc)
1627 {
1628         dmu_recv_begin_arg_t drba = { 0 };
1629 
1630         bzero(drc, sizeof (dmu_recv_cookie_t));
1631         drc->drc_drr_begin = drr_begin;
1632         drc->drc_drrb = &drr_begin->drr_u.drr_begin;
1633         drc->drc_tosnap = tosnap;
1634         drc->drc_tofs = tofs;
1635         drc->drc_force = force;
1636         drc->drc_resumable = resumable;
1637         drc->drc_cred = CRED();
1638 
1639         if (drc->drc_drrb->drr_magic == BSWAP_64(DMU_BACKUP_MAGIC)) {
1640                 drc->drc_byteswap = B_TRUE;
1641                 fletcher_4_incremental_byteswap(drr_begin,
1642                     sizeof (dmu_replay_record_t), &drc->drc_cksum);
1643                 byteswap_record(drr_begin);
1644         } else if (drc->drc_drrb->drr_magic == DMU_BACKUP_MAGIC) {
1645                 fletcher_4_incremental_native(drr_begin,
1646                     sizeof (dmu_replay_record_t), &drc->drc_cksum);
1647         } else {
1648                 return (SET_ERROR(EINVAL));
1649         }
1650 
1651         drba.drba_origin = origin;
1652         drba.drba_cookie = drc;
1653         drba.drba_cred = CRED();
1654 
1655         if (DMU_GET_FEATUREFLAGS(drc->drc_drrb->drr_versioninfo) &
1656             DMU_BACKUP_FEATURE_RESUMING) {
1657                 return (dsl_sync_task(tofs,
1658                     dmu_recv_resume_begin_check, dmu_recv_resume_begin_sync,
1659                     &drba, 5, ZFS_SPACE_CHECK_NORMAL));
1660         } else  {
1661                 return (dsl_sync_task(tofs,
1662                     dmu_recv_begin_check, dmu_recv_begin_sync,
1663                     &drba, 5, ZFS_SPACE_CHECK_NORMAL));
1664         }
1665 }
1666 
1667 struct receive_record_arg {
1668         dmu_replay_record_t header;
1669         void *payload; /* Pointer to a buffer containing the payload */
1670         /*
1671          * If the record is a write, pointer to the arc_buf_t containing the
1672          * payload.
1673          */
1674         arc_buf_t *write_buf;
1675         int payload_size;
1676         uint64_t bytes_read; /* bytes read from stream when record created */
1677         boolean_t eos_marker; /* Marks the end of the stream */
1678         bqueue_node_t node;
1679 };
1680 
1681 struct receive_writer_arg {
1682         objset_t *os;
1683         boolean_t byteswap;
1684         bqueue_t q;
1685 
1686         /*
1687          * These three args are used to signal to the main thread that we're
1688          * done.
1689          */
1690         kmutex_t mutex;
1691         kcondvar_t cv;
1692         boolean_t done;
1693 
1694         int err;
1695         /* A map from guid to dataset to help handle dedup'd streams. */
1696         avl_tree_t *guid_to_ds_map;
1697         boolean_t resumable;
1698         uint64_t last_object, last_offset;
1699         uint64_t bytes_read; /* bytes read when current record created */
1700 };
1701 
1702 struct objlist {
1703         list_t list; /* List of struct receive_objnode. */
1704         /*
1705          * Last object looked up. Used to assert that objects are being looked
1706          * up in ascending order.
1707          */
1708         uint64_t last_lookup;
1709 };
1710 
1711 struct receive_objnode {
1712         list_node_t node;
1713         uint64_t object;
1714 };
1715 
1716 struct receive_arg  {
1717         objset_t *os;
1718         vnode_t *vp; /* The vnode to read the stream from */
1719         uint64_t voff; /* The current offset in the stream */
1720         uint64_t bytes_read;
1721         /*
1722          * A record that has had its payload read in, but hasn't yet been handed
1723          * off to the worker thread.
1724          */
1725         struct receive_record_arg *rrd;
1726         /* A record that has had its header read in, but not its payload. */
1727         struct receive_record_arg *next_rrd;
1728         zio_cksum_t cksum;
1729         zio_cksum_t prev_cksum;
1730         int err;
1731         boolean_t byteswap;
1732         /* Sorted list of objects not to issue prefetches for. */
1733         struct objlist ignore_objlist;
1734 };
1735 
1736 typedef struct guid_map_entry {
1737         uint64_t        guid;
1738         dsl_dataset_t   *gme_ds;
1739         avl_node_t      avlnode;
1740 } guid_map_entry_t;
1741 
1742 static int
1743 guid_compare(const void *arg1, const void *arg2)
1744 {
1745         const guid_map_entry_t *gmep1 = arg1;
1746         const guid_map_entry_t *gmep2 = arg2;
1747 
1748         if (gmep1->guid < gmep2->guid)
1749                 return (-1);
1750         else if (gmep1->guid > gmep2->guid)
1751                 return (1);
1752         return (0);
1753 }
1754 
1755 static void
1756 free_guid_map_onexit(void *arg)
1757 {
1758         avl_tree_t *ca = arg;
1759         void *cookie = NULL;
1760         guid_map_entry_t *gmep;
1761 
1762         while ((gmep = avl_destroy_nodes(ca, &cookie)) != NULL) {
1763                 dsl_dataset_long_rele(gmep->gme_ds, gmep);
1764                 dsl_dataset_rele(gmep->gme_ds, gmep);
1765                 kmem_free(gmep, sizeof (guid_map_entry_t));
1766         }
1767         avl_destroy(ca);
1768         kmem_free(ca, sizeof (avl_tree_t));
1769 }
1770 
1771 static int
1772 receive_read(struct receive_arg *ra, int len, void *buf)
1773 {
1774         int done = 0;
1775 
1776         /*
1777          * The code doesn't rely on this (lengths being multiples of 8).  See
1778          * comment in dump_bytes.
1779          */
1780         ASSERT0(len % 8);
1781 
1782         while (done < len) {
1783                 ssize_t resid;
1784 
1785                 ra->err = vn_rdwr(UIO_READ, ra->vp,
1786                     (char *)buf + done, len - done,
1787                     ra->voff, UIO_SYSSPACE, FAPPEND,
1788                     RLIM64_INFINITY, CRED(), &resid);
1789 
1790                 if (resid == len - done) {
1791                         /*
1792                          * Note: ECKSUM indicates that the receive
1793                          * was interrupted and can potentially be resumed.
1794                          */
1795                         ra->err = SET_ERROR(ECKSUM);
1796                 }
1797                 ra->voff += len - done - resid;
1798                 done = len - resid;
1799                 if (ra->err != 0)
1800                         return (ra->err);
1801         }
1802 
1803         ra->bytes_read += len;
1804 
1805         ASSERT3U(done, ==, len);
1806         return (0);
1807 }
1808 
1809 static void
1810 byteswap_record(dmu_replay_record_t *drr)
1811 {
1812 #define DO64(X) (drr->drr_u.X = BSWAP_64(drr->drr_u.X))
1813 #define DO32(X) (drr->drr_u.X = BSWAP_32(drr->drr_u.X))
1814         drr->drr_type = BSWAP_32(drr->drr_type);
1815         drr->drr_payloadlen = BSWAP_32(drr->drr_payloadlen);
1816 
1817         switch (drr->drr_type) {
1818         case DRR_BEGIN:
1819                 DO64(drr_begin.drr_magic);
1820                 DO64(drr_begin.drr_versioninfo);
1821                 DO64(drr_begin.drr_creation_time);
1822                 DO32(drr_begin.drr_type);
1823                 DO32(drr_begin.drr_flags);
1824                 DO64(drr_begin.drr_toguid);
1825                 DO64(drr_begin.drr_fromguid);
1826                 break;
1827         case DRR_OBJECT:
1828                 DO64(drr_object.drr_object);
1829                 DO32(drr_object.drr_type);
1830                 DO32(drr_object.drr_bonustype);
1831                 DO32(drr_object.drr_blksz);
1832                 DO32(drr_object.drr_bonuslen);
1833                 DO64(drr_object.drr_toguid);
1834                 break;
1835         case DRR_FREEOBJECTS:
1836                 DO64(drr_freeobjects.drr_firstobj);
1837                 DO64(drr_freeobjects.drr_numobjs);
1838                 DO64(drr_freeobjects.drr_toguid);
1839                 break;
1840         case DRR_WRITE:
1841                 DO64(drr_write.drr_object);
1842                 DO32(drr_write.drr_type);
1843                 DO64(drr_write.drr_offset);
1844                 DO64(drr_write.drr_length);
1845                 DO64(drr_write.drr_toguid);
1846                 ZIO_CHECKSUM_BSWAP(&drr->drr_u.drr_write.drr_key.ddk_cksum);
1847                 DO64(drr_write.drr_key.ddk_prop);
1848                 break;
1849         case DRR_WRITE_BYREF:
1850                 DO64(drr_write_byref.drr_object);
1851                 DO64(drr_write_byref.drr_offset);
1852                 DO64(drr_write_byref.drr_length);
1853                 DO64(drr_write_byref.drr_toguid);
1854                 DO64(drr_write_byref.drr_refguid);
1855                 DO64(drr_write_byref.drr_refobject);
1856                 DO64(drr_write_byref.drr_refoffset);
1857                 ZIO_CHECKSUM_BSWAP(&drr->drr_u.drr_write_byref.
1858                     drr_key.ddk_cksum);
1859                 DO64(drr_write_byref.drr_key.ddk_prop);
1860                 break;
1861         case DRR_WRITE_EMBEDDED:
1862                 DO64(drr_write_embedded.drr_object);
1863                 DO64(drr_write_embedded.drr_offset);
1864                 DO64(drr_write_embedded.drr_length);
1865                 DO64(drr_write_embedded.drr_toguid);
1866                 DO32(drr_write_embedded.drr_lsize);
1867                 DO32(drr_write_embedded.drr_psize);
1868                 break;
1869         case DRR_FREE:
1870                 DO64(drr_free.drr_object);
1871                 DO64(drr_free.drr_offset);
1872                 DO64(drr_free.drr_length);
1873                 DO64(drr_free.drr_toguid);
1874                 break;
1875         case DRR_SPILL:
1876                 DO64(drr_spill.drr_object);
1877                 DO64(drr_spill.drr_length);
1878                 DO64(drr_spill.drr_toguid);
1879                 break;
1880         case DRR_END:
1881                 DO64(drr_end.drr_toguid);
1882                 ZIO_CHECKSUM_BSWAP(&drr->drr_u.drr_end.drr_checksum);
1883                 break;
1884         }
1885 
1886         if (drr->drr_type != DRR_BEGIN) {
1887                 ZIO_CHECKSUM_BSWAP(&drr->drr_u.drr_checksum.drr_checksum);
1888         }
1889 
1890 #undef DO64
1891 #undef DO32
1892 }
1893 
1894 static inline uint8_t
1895 deduce_nblkptr(dmu_object_type_t bonus_type, uint64_t bonus_size)
1896 {
1897         if (bonus_type == DMU_OT_SA) {
1898                 return (1);
1899         } else {
1900                 return (1 +
1901                     ((DN_MAX_BONUSLEN - bonus_size) >> SPA_BLKPTRSHIFT));
1902         }
1903 }
1904 
1905 static void
1906 save_resume_state(struct receive_writer_arg *rwa,
1907     uint64_t object, uint64_t offset, dmu_tx_t *tx)
1908 {
1909         int txgoff = dmu_tx_get_txg(tx) & TXG_MASK;
1910 
1911         if (!rwa->resumable)
1912                 return;
1913 
1914         /*
1915          * We use ds_resume_bytes[] != 0 to indicate that we need to
1916          * update this on disk, so it must not be 0.
1917          */
1918         ASSERT(rwa->bytes_read != 0);
1919 
1920         /*
1921          * We only resume from write records, which have a valid
1922          * (non-meta-dnode) object number.
1923          */
1924         ASSERT(object != 0);
1925 
1926         /*
1927          * For resuming to work correctly, we must receive records in order,
1928          * sorted by object,offset.  This is checked by the callers, but
1929          * assert it here for good measure.
1930          */
1931         ASSERT3U(object, >=, rwa->os->os_dsl_dataset->ds_resume_object[txgoff]);
1932         ASSERT(object != rwa->os->os_dsl_dataset->ds_resume_object[txgoff] ||
1933             offset >= rwa->os->os_dsl_dataset->ds_resume_offset[txgoff]);
1934         ASSERT3U(rwa->bytes_read, >=,
1935             rwa->os->os_dsl_dataset->ds_resume_bytes[txgoff]);
1936 
1937         rwa->os->os_dsl_dataset->ds_resume_object[txgoff] = object;
1938         rwa->os->os_dsl_dataset->ds_resume_offset[txgoff] = offset;
1939         rwa->os->os_dsl_dataset->ds_resume_bytes[txgoff] = rwa->bytes_read;
1940 }
1941 
1942 static int
1943 receive_object(struct receive_writer_arg *rwa, struct drr_object *drro,
1944     void *data)
1945 {
1946         dmu_object_info_t doi;
1947         dmu_tx_t *tx;
1948         uint64_t object;
1949         int err;
1950 
1951         if (drro->drr_type == DMU_OT_NONE ||
1952             !DMU_OT_IS_VALID(drro->drr_type) ||
1953             !DMU_OT_IS_VALID(drro->drr_bonustype) ||
1954             drro->drr_checksumtype >= ZIO_CHECKSUM_FUNCTIONS ||
1955             drro->drr_compress >= ZIO_COMPRESS_FUNCTIONS ||
1956             P2PHASE(drro->drr_blksz, SPA_MINBLOCKSIZE) ||
1957             drro->drr_blksz < SPA_MINBLOCKSIZE ||
1958             drro->drr_blksz > spa_maxblocksize(dmu_objset_spa(rwa->os)) ||
1959             drro->drr_bonuslen > DN_MAX_BONUSLEN) {
1960                 return (SET_ERROR(EINVAL));
1961         }
1962 
1963         err = dmu_object_info(rwa->os, drro->drr_object, &doi);
1964 
1965         if (err != 0 && err != ENOENT)
1966                 return (SET_ERROR(EINVAL));
1967         object = err == 0 ? drro->drr_object : DMU_NEW_OBJECT;
1968 
1969         /*
1970          * If we are losing blkptrs or changing the block size this must
1971          * be a new file instance.  We must clear out the previous file
1972          * contents before we can change this type of metadata in the dnode.
1973          */
1974         if (err == 0) {
1975                 int nblkptr;
1976 
1977                 nblkptr = deduce_nblkptr(drro->drr_bonustype,
1978                     drro->drr_bonuslen);
1979 
1980                 if (drro->drr_blksz != doi.doi_data_block_size ||
1981                     nblkptr < doi.doi_nblkptr) {
1982                         err = dmu_free_long_range(rwa->os, drro->drr_object,
1983                             0, DMU_OBJECT_END);
1984                         if (err != 0)
1985                                 return (SET_ERROR(EINVAL));
1986                 }
1987         }
1988 
1989         tx = dmu_tx_create(rwa->os);
1990         dmu_tx_hold_bonus(tx, object);
1991         err = dmu_tx_assign(tx, TXG_WAIT);
1992         if (err != 0) {
1993                 dmu_tx_abort(tx);
1994                 return (err);
1995         }
1996 
1997         if (object == DMU_NEW_OBJECT) {
1998                 /* currently free, want to be allocated */
1999                 err = dmu_object_claim(rwa->os, drro->drr_object,
2000                     drro->drr_type, drro->drr_blksz,
2001                     drro->drr_bonustype, drro->drr_bonuslen, tx);
2002         } else if (drro->drr_type != doi.doi_type ||
2003             drro->drr_blksz != doi.doi_data_block_size ||
2004             drro->drr_bonustype != doi.doi_bonus_type ||
2005             drro->drr_bonuslen != doi.doi_bonus_size) {
2006                 /* currently allocated, but with different properties */
2007                 err = dmu_object_reclaim(rwa->os, drro->drr_object,
2008                     drro->drr_type, drro->drr_blksz,
2009                     drro->drr_bonustype, drro->drr_bonuslen, tx);
2010         }
2011         if (err != 0) {
2012                 dmu_tx_commit(tx);
2013                 return (SET_ERROR(EINVAL));
2014         }
2015 
2016         dmu_object_set_checksum(rwa->os, drro->drr_object,
2017             drro->drr_checksumtype, tx);
2018         dmu_object_set_compress(rwa->os, drro->drr_object,
2019             drro->drr_compress, tx);
2020 
2021         if (data != NULL) {
2022                 dmu_buf_t *db;
2023 
2024                 VERIFY0(dmu_bonus_hold(rwa->os, drro->drr_object, FTAG, &db));
2025                 dmu_buf_will_dirty(db, tx);
2026 
2027                 ASSERT3U(db->db_size, >=, drro->drr_bonuslen);
2028                 bcopy(data, db->db_data, drro->drr_bonuslen);
2029                 if (rwa->byteswap) {
2030                         dmu_object_byteswap_t byteswap =
2031                             DMU_OT_BYTESWAP(drro->drr_bonustype);
2032                         dmu_ot_byteswap[byteswap].ob_func(db->db_data,
2033                             drro->drr_bonuslen);
2034                 }
2035                 dmu_buf_rele(db, FTAG);
2036         }
2037         dmu_tx_commit(tx);
2038 
2039         return (0);
2040 }
2041 
2042 /* ARGSUSED */
2043 static int
2044 receive_freeobjects(struct receive_writer_arg *rwa,
2045     struct drr_freeobjects *drrfo)
2046 {
2047         uint64_t obj;
2048         int next_err = 0;
2049 
2050         if (drrfo->drr_firstobj + drrfo->drr_numobjs < drrfo->drr_firstobj)
2051                 return (SET_ERROR(EINVAL));
2052 
2053         for (obj = drrfo->drr_firstobj;
2054             obj < drrfo->drr_firstobj + drrfo->drr_numobjs && next_err == 0;
2055             next_err = dmu_object_next(rwa->os, &obj, FALSE, 0)) {
2056                 int err;
2057 
2058                 if (dmu_object_info(rwa->os, obj, NULL) != 0)
2059                         continue;
2060 
2061                 err = dmu_free_long_object(rwa->os, obj);
2062                 if (err != 0)
2063                         return (err);
2064         }
2065         if (next_err != ESRCH)
2066                 return (next_err);
2067         return (0);
2068 }
2069 
2070 static int
2071 receive_write(struct receive_writer_arg *rwa, struct drr_write *drrw,
2072     arc_buf_t *abuf)
2073 {
2074         dmu_tx_t *tx;
2075         int err;
2076 
2077         if (drrw->drr_offset + drrw->drr_length < drrw->drr_offset ||
2078             !DMU_OT_IS_VALID(drrw->drr_type))
2079                 return (SET_ERROR(EINVAL));
2080 
2081         /*
2082          * For resuming to work, records must be in increasing order
2083          * by (object, offset).
2084          */
2085         if (drrw->drr_object < rwa->last_object ||
2086             (drrw->drr_object == rwa->last_object &&
2087             drrw->drr_offset < rwa->last_offset)) {
2088                 return (SET_ERROR(EINVAL));
2089         }
2090         rwa->last_object = drrw->drr_object;
2091         rwa->last_offset = drrw->drr_offset;
2092 
2093         if (dmu_object_info(rwa->os, drrw->drr_object, NULL) != 0)
2094                 return (SET_ERROR(EINVAL));
2095 
2096         tx = dmu_tx_create(rwa->os);
2097 
2098         dmu_tx_hold_write(tx, drrw->drr_object,
2099             drrw->drr_offset, drrw->drr_length);
2100         err = dmu_tx_assign(tx, TXG_WAIT);
2101         if (err != 0) {
2102                 dmu_tx_abort(tx);
2103                 return (err);
2104         }
2105         if (rwa->byteswap) {
2106                 dmu_object_byteswap_t byteswap =
2107                     DMU_OT_BYTESWAP(drrw->drr_type);
2108                 dmu_ot_byteswap[byteswap].ob_func(abuf->b_data,
2109                     drrw->drr_length);
2110         }
2111 
2112         dmu_buf_t *bonus;
2113         if (dmu_bonus_hold(rwa->os, drrw->drr_object, FTAG, &bonus) != 0)
2114                 return (SET_ERROR(EINVAL));
2115         dmu_assign_arcbuf(bonus, drrw->drr_offset, abuf, tx);
2116 
2117         /*
2118          * Note: If the receive fails, we want the resume stream to start
2119          * with the same record that we last successfully received (as opposed
2120          * to the next record), so that we can verify that we are
2121          * resuming from the correct location.
2122          */
2123         save_resume_state(rwa, drrw->drr_object, drrw->drr_offset, tx);
2124         dmu_tx_commit(tx);
2125         dmu_buf_rele(bonus, FTAG);
2126 
2127         return (0);
2128 }
2129 
2130 /*
2131  * Handle a DRR_WRITE_BYREF record.  This record is used in dedup'ed
2132  * streams to refer to a copy of the data that is already on the
2133  * system because it came in earlier in the stream.  This function
2134  * finds the earlier copy of the data, and uses that copy instead of
2135  * data from the stream to fulfill this write.
2136  */
2137 static int
2138 receive_write_byref(struct receive_writer_arg *rwa,
2139     struct drr_write_byref *drrwbr)
2140 {
2141         dmu_tx_t *tx;
2142         int err;
2143         guid_map_entry_t gmesrch;
2144         guid_map_entry_t *gmep;
2145         avl_index_t where;
2146         objset_t *ref_os = NULL;
2147         dmu_buf_t *dbp;
2148 
2149         if (drrwbr->drr_offset + drrwbr->drr_length < drrwbr->drr_offset)
2150                 return (SET_ERROR(EINVAL));
2151 
2152         /*
2153          * If the GUID of the referenced dataset is different from the
2154          * GUID of the target dataset, find the referenced dataset.
2155          */
2156         if (drrwbr->drr_toguid != drrwbr->drr_refguid) {
2157                 gmesrch.guid = drrwbr->drr_refguid;
2158                 if ((gmep = avl_find(rwa->guid_to_ds_map, &gmesrch,
2159                     &where)) == NULL) {
2160                         return (SET_ERROR(EINVAL));
2161                 }
2162                 if (dmu_objset_from_ds(gmep->gme_ds, &ref_os))
2163                         return (SET_ERROR(EINVAL));
2164         } else {
2165                 ref_os = rwa->os;
2166         }
2167 
2168         err = dmu_buf_hold(ref_os, drrwbr->drr_refobject,
2169             drrwbr->drr_refoffset, FTAG, &dbp, DMU_READ_PREFETCH);
2170         if (err != 0)
2171                 return (err);
2172 
2173         tx = dmu_tx_create(rwa->os);
2174 
2175         dmu_tx_hold_write(tx, drrwbr->drr_object,
2176             drrwbr->drr_offset, drrwbr->drr_length);
2177         err = dmu_tx_assign(tx, TXG_WAIT);
2178         if (err != 0) {
2179                 dmu_tx_abort(tx);
2180                 return (err);
2181         }
2182         dmu_write(rwa->os, drrwbr->drr_object,
2183             drrwbr->drr_offset, drrwbr->drr_length, dbp->db_data, tx);
2184         dmu_buf_rele(dbp, FTAG);
2185 
2186         /* See comment in restore_write. */
2187         save_resume_state(rwa, drrwbr->drr_object, drrwbr->drr_offset, tx);
2188         dmu_tx_commit(tx);
2189         return (0);
2190 }
2191 
2192 static int
2193 receive_write_embedded(struct receive_writer_arg *rwa,
2194     struct drr_write_embedded *drrwe, void *data)
2195 {
2196         dmu_tx_t *tx;
2197         int err;
2198 
2199         if (drrwe->drr_offset + drrwe->drr_length < drrwe->drr_offset)
2200                 return (EINVAL);
2201 
2202         if (drrwe->drr_psize > BPE_PAYLOAD_SIZE)
2203                 return (EINVAL);
2204 
2205         if (drrwe->drr_etype >= NUM_BP_EMBEDDED_TYPES)
2206                 return (EINVAL);
2207         if (drrwe->drr_compression >= ZIO_COMPRESS_FUNCTIONS)
2208                 return (EINVAL);
2209 
2210         tx = dmu_tx_create(rwa->os);
2211 
2212         dmu_tx_hold_write(tx, drrwe->drr_object,
2213             drrwe->drr_offset, drrwe->drr_length);
2214         err = dmu_tx_assign(tx, TXG_WAIT);
2215         if (err != 0) {
2216                 dmu_tx_abort(tx);
2217                 return (err);
2218         }
2219 
2220         dmu_write_embedded(rwa->os, drrwe->drr_object,
2221             drrwe->drr_offset, data, drrwe->drr_etype,
2222             drrwe->drr_compression, drrwe->drr_lsize, drrwe->drr_psize,
2223             rwa->byteswap ^ ZFS_HOST_BYTEORDER, tx);
2224 
2225         /* See comment in restore_write. */
2226         save_resume_state(rwa, drrwe->drr_object, drrwe->drr_offset, tx);
2227         dmu_tx_commit(tx);
2228         return (0);
2229 }
2230 
2231 static int
2232 receive_spill(struct receive_writer_arg *rwa, struct drr_spill *drrs,
2233     void *data)
2234 {
2235         dmu_tx_t *tx;
2236         dmu_buf_t *db, *db_spill;
2237         int err;
2238 
2239         if (drrs->drr_length < SPA_MINBLOCKSIZE ||
2240             drrs->drr_length > spa_maxblocksize(dmu_objset_spa(rwa->os)))
2241                 return (SET_ERROR(EINVAL));
2242 
2243         if (dmu_object_info(rwa->os, drrs->drr_object, NULL) != 0)
2244                 return (SET_ERROR(EINVAL));
2245 
2246         VERIFY0(dmu_bonus_hold(rwa->os, drrs->drr_object, FTAG, &db));
2247         if ((err = dmu_spill_hold_by_bonus(db, FTAG, &db_spill)) != 0) {
2248                 dmu_buf_rele(db, FTAG);
2249                 return (err);
2250         }
2251 
2252         tx = dmu_tx_create(rwa->os);
2253 
2254         dmu_tx_hold_spill(tx, db->db_object);
2255 
2256         err = dmu_tx_assign(tx, TXG_WAIT);
2257         if (err != 0) {
2258                 dmu_buf_rele(db, FTAG);
2259                 dmu_buf_rele(db_spill, FTAG);
2260                 dmu_tx_abort(tx);
2261                 return (err);
2262         }
2263         dmu_buf_will_dirty(db_spill, tx);
2264 
2265         if (db_spill->db_size < drrs->drr_length)
2266                 VERIFY(0 == dbuf_spill_set_blksz(db_spill,
2267                     drrs->drr_length, tx));
2268         bcopy(data, db_spill->db_data, drrs->drr_length);
2269 
2270         dmu_buf_rele(db, FTAG);
2271         dmu_buf_rele(db_spill, FTAG);
2272 
2273         dmu_tx_commit(tx);
2274         return (0);
2275 }
2276 
2277 /* ARGSUSED */
2278 static int
2279 receive_free(struct receive_writer_arg *rwa, struct drr_free *drrf)
2280 {
2281         int err;
2282 
2283         if (drrf->drr_length != -1ULL &&
2284             drrf->drr_offset + drrf->drr_length < drrf->drr_offset)
2285                 return (SET_ERROR(EINVAL));
2286 
2287         if (dmu_object_info(rwa->os, drrf->drr_object, NULL) != 0)
2288                 return (SET_ERROR(EINVAL));
2289 
2290         err = dmu_free_long_range(rwa->os, drrf->drr_object,
2291             drrf->drr_offset, drrf->drr_length);
2292 
2293         return (err);
2294 }
2295 
2296 /* used to destroy the drc_ds on error */
2297 static void
2298 dmu_recv_cleanup_ds(dmu_recv_cookie_t *drc)
2299 {
2300         if (drc->drc_resumable) {
2301                 /* wait for our resume state to be written to disk */
2302                 txg_wait_synced(drc->drc_ds->ds_dir->dd_pool, 0);
2303                 dsl_dataset_disown(drc->drc_ds, dmu_recv_tag);
2304         } else {
2305                 char name[ZFS_MAX_DATASET_NAME_LEN];
2306                 dsl_dataset_name(drc->drc_ds, name);
2307                 dsl_dataset_disown(drc->drc_ds, dmu_recv_tag);
2308                 (void) dsl_destroy_head(name);
2309         }
2310 }
2311 
2312 static void
2313 receive_cksum(struct receive_arg *ra, int len, void *buf)
2314 {
2315         if (ra->byteswap) {
2316                 fletcher_4_incremental_byteswap(buf, len, &ra->cksum);
2317         } else {
2318                 fletcher_4_incremental_native(buf, len, &ra->cksum);
2319         }
2320 }
2321 
2322 /*
2323  * Read the payload into a buffer of size len, and update the current record's
2324  * payload field.
2325  * Allocate ra->next_rrd and read the next record's header into
2326  * ra->next_rrd->header.
2327  * Verify checksum of payload and next record.
2328  */
2329 static int
2330 receive_read_payload_and_next_header(struct receive_arg *ra, int len, void *buf)
2331 {
2332         int err;
2333 
2334         if (len != 0) {
2335                 ASSERT3U(len, <=, SPA_MAXBLOCKSIZE);
2336                 err = receive_read(ra, len, buf);
2337                 if (err != 0)
2338                         return (err);
2339                 receive_cksum(ra, len, buf);
2340 
2341                 /* note: rrd is NULL when reading the begin record's payload */
2342                 if (ra->rrd != NULL) {
2343                         ra->rrd->payload = buf;
2344                         ra->rrd->payload_size = len;
2345                         ra->rrd->bytes_read = ra->bytes_read;
2346                 }
2347         }
2348 
2349         ra->prev_cksum = ra->cksum;
2350 
2351         ra->next_rrd = kmem_zalloc(sizeof (*ra->next_rrd), KM_SLEEP);
2352         err = receive_read(ra, sizeof (ra->next_rrd->header),
2353             &ra->next_rrd->header);
2354         ra->next_rrd->bytes_read = ra->bytes_read;
2355         if (err != 0) {
2356                 kmem_free(ra->next_rrd, sizeof (*ra->next_rrd));
2357                 ra->next_rrd = NULL;
2358                 return (err);
2359         }
2360         if (ra->next_rrd->header.drr_type == DRR_BEGIN) {
2361                 kmem_free(ra->next_rrd, sizeof (*ra->next_rrd));
2362                 ra->next_rrd = NULL;
2363                 return (SET_ERROR(EINVAL));
2364         }
2365 
2366         /*
2367          * Note: checksum is of everything up to but not including the
2368          * checksum itself.
2369          */
2370         ASSERT3U(offsetof(dmu_replay_record_t, drr_u.drr_checksum.drr_checksum),
2371             ==, sizeof (dmu_replay_record_t) - sizeof (zio_cksum_t));
2372         receive_cksum(ra,
2373             offsetof(dmu_replay_record_t, drr_u.drr_checksum.drr_checksum),
2374             &ra->next_rrd->header);
2375 
2376         zio_cksum_t cksum_orig =
2377             ra->next_rrd->header.drr_u.drr_checksum.drr_checksum;
2378         zio_cksum_t *cksump =
2379             &ra->next_rrd->header.drr_u.drr_checksum.drr_checksum;
2380 
2381         if (ra->byteswap)
2382                 byteswap_record(&ra->next_rrd->header);
2383 
2384         if ((!ZIO_CHECKSUM_IS_ZERO(cksump)) &&
2385             !ZIO_CHECKSUM_EQUAL(ra->cksum, *cksump)) {
2386                 kmem_free(ra->next_rrd, sizeof (*ra->next_rrd));
2387                 ra->next_rrd = NULL;
2388                 return (SET_ERROR(ECKSUM));
2389         }
2390 
2391         receive_cksum(ra, sizeof (cksum_orig), &cksum_orig);
2392 
2393         return (0);
2394 }
2395 
2396 static void
2397 objlist_create(struct objlist *list)
2398 {
2399         list_create(&list->list, sizeof (struct receive_objnode),
2400             offsetof(struct receive_objnode, node));
2401         list->last_lookup = 0;
2402 }
2403 
2404 static void
2405 objlist_destroy(struct objlist *list)
2406 {
2407         for (struct receive_objnode *n = list_remove_head(&list->list);
2408             n != NULL; n = list_remove_head(&list->list)) {
2409                 kmem_free(n, sizeof (*n));
2410         }
2411         list_destroy(&list->list);
2412 }
2413 
2414 /*
2415  * This function looks through the objlist to see if the specified object number
2416  * is contained in the objlist.  In the process, it will remove all object
2417  * numbers in the list that are smaller than the specified object number.  Thus,
2418  * any lookup of an object number smaller than a previously looked up object
2419  * number will always return false; therefore, all lookups should be done in
2420  * ascending order.
2421  */
2422 static boolean_t
2423 objlist_exists(struct objlist *list, uint64_t object)
2424 {
2425         struct receive_objnode *node = list_head(&list->list);
2426         ASSERT3U(object, >=, list->last_lookup);
2427         list->last_lookup = object;
2428         while (node != NULL && node->object < object) {
2429                 VERIFY3P(node, ==, list_remove_head(&list->list));
2430                 kmem_free(node, sizeof (*node));
2431                 node = list_head(&list->list);
2432         }
2433         return (node != NULL && node->object == object);
2434 }
2435 
2436 /*
2437  * The objlist is a list of object numbers stored in ascending order.  However,
2438  * the insertion of new object numbers does not seek out the correct location to
2439  * store a new object number; instead, it appends it to the list for simplicity.
2440  * Thus, any users must take care to only insert new object numbers in ascending
2441  * order.
2442  */
2443 static void
2444 objlist_insert(struct objlist *list, uint64_t object)
2445 {
2446         struct receive_objnode *node = kmem_zalloc(sizeof (*node), KM_SLEEP);
2447         node->object = object;
2448 #ifdef ZFS_DEBUG
2449         struct receive_objnode *last_object = list_tail(&list->list);
2450         uint64_t last_objnum = (last_object != NULL ? last_object->object : 0);
2451         ASSERT3U(node->object, >, last_objnum);
2452 #endif
2453         list_insert_tail(&list->list, node);
2454 }
2455 
2456 /*
2457  * Issue the prefetch reads for any necessary indirect blocks.
2458  *
2459  * We use the object ignore list to tell us whether or not to issue prefetches
2460  * for a given object.  We do this for both correctness (in case the blocksize
2461  * of an object has changed) and performance (if the object doesn't exist, don't
2462  * needlessly try to issue prefetches).  We also trim the list as we go through
2463  * the stream to prevent it from growing to an unbounded size.
2464  *
2465  * The object numbers within will always be in sorted order, and any write
2466  * records we see will also be in sorted order, but they're not sorted with
2467  * respect to each other (i.e. we can get several object records before
2468  * receiving each object's write records).  As a result, once we've reached a
2469  * given object number, we can safely remove any reference to lower object
2470  * numbers in the ignore list. In practice, we receive up to 32 object records
2471  * before receiving write records, so the list can have up to 32 nodes in it.
2472  */
2473 /* ARGSUSED */
2474 static void
2475 receive_read_prefetch(struct receive_arg *ra,
2476     uint64_t object, uint64_t offset, uint64_t length)
2477 {
2478         if (!objlist_exists(&ra->ignore_objlist, object)) {
2479                 dmu_prefetch(ra->os, object, 1, offset, length,
2480                     ZIO_PRIORITY_SYNC_READ);
2481         }
2482 }
2483 
2484 /*
2485  * Read records off the stream, issuing any necessary prefetches.
2486  */
2487 static int
2488 receive_read_record(struct receive_arg *ra)
2489 {
2490         int err;
2491 
2492         switch (ra->rrd->header.drr_type) {
2493         case DRR_OBJECT:
2494         {
2495                 struct drr_object *drro = &ra->rrd->header.drr_u.drr_object;
2496                 uint32_t size = P2ROUNDUP(drro->drr_bonuslen, 8);
2497                 void *buf = kmem_zalloc(size, KM_SLEEP);
2498                 dmu_object_info_t doi;
2499                 err = receive_read_payload_and_next_header(ra, size, buf);
2500                 if (err != 0) {
2501                         kmem_free(buf, size);
2502                         return (err);
2503                 }
2504                 err = dmu_object_info(ra->os, drro->drr_object, &doi);
2505                 /*
2506                  * See receive_read_prefetch for an explanation why we're
2507                  * storing this object in the ignore_obj_list.
2508                  */
2509                 if (err == ENOENT ||
2510                     (err == 0 && doi.doi_data_block_size != drro->drr_blksz)) {
2511                         objlist_insert(&ra->ignore_objlist, drro->drr_object);
2512                         err = 0;
2513                 }
2514                 return (err);
2515         }
2516         case DRR_FREEOBJECTS:
2517         {
2518                 err = receive_read_payload_and_next_header(ra, 0, NULL);
2519                 return (err);
2520         }
2521         case DRR_WRITE:
2522         {
2523                 struct drr_write *drrw = &ra->rrd->header.drr_u.drr_write;
2524                 arc_buf_t *abuf = arc_loan_buf(dmu_objset_spa(ra->os),
2525                     drrw->drr_length);
2526 
2527                 err = receive_read_payload_and_next_header(ra,
2528                     drrw->drr_length, abuf->b_data);
2529                 if (err != 0) {
2530                         dmu_return_arcbuf(abuf);
2531                         return (err);
2532                 }
2533                 ra->rrd->write_buf = abuf;
2534                 receive_read_prefetch(ra, drrw->drr_object, drrw->drr_offset,
2535                     drrw->drr_length);
2536                 return (err);
2537         }
2538         case DRR_WRITE_BYREF:
2539         {
2540                 struct drr_write_byref *drrwb =
2541                     &ra->rrd->header.drr_u.drr_write_byref;
2542                 err = receive_read_payload_and_next_header(ra, 0, NULL);
2543                 receive_read_prefetch(ra, drrwb->drr_object, drrwb->drr_offset,
2544                     drrwb->drr_length);
2545                 return (err);
2546         }
2547         case DRR_WRITE_EMBEDDED:
2548         {
2549                 struct drr_write_embedded *drrwe =
2550                     &ra->rrd->header.drr_u.drr_write_embedded;
2551                 uint32_t size = P2ROUNDUP(drrwe->drr_psize, 8);
2552                 void *buf = kmem_zalloc(size, KM_SLEEP);
2553 
2554                 err = receive_read_payload_and_next_header(ra, size, buf);
2555                 if (err != 0) {
2556                         kmem_free(buf, size);
2557                         return (err);
2558                 }
2559 
2560                 receive_read_prefetch(ra, drrwe->drr_object, drrwe->drr_offset,
2561                     drrwe->drr_length);
2562                 return (err);
2563         }
2564         case DRR_FREE:
2565         {
2566                 /*
2567                  * It might be beneficial to prefetch indirect blocks here, but
2568                  * we don't really have the data to decide for sure.
2569                  */
2570                 err = receive_read_payload_and_next_header(ra, 0, NULL);
2571                 return (err);
2572         }
2573         case DRR_END:
2574         {
2575                 struct drr_end *drre = &ra->rrd->header.drr_u.drr_end;
2576                 if (!ZIO_CHECKSUM_EQUAL(ra->prev_cksum, drre->drr_checksum))
2577                         return (SET_ERROR(ECKSUM));
2578                 return (0);
2579         }
2580         case DRR_SPILL:
2581         {
2582                 struct drr_spill *drrs = &ra->rrd->header.drr_u.drr_spill;
2583                 void *buf = kmem_zalloc(drrs->drr_length, KM_SLEEP);
2584                 err = receive_read_payload_and_next_header(ra, drrs->drr_length,
2585                     buf);
2586                 if (err != 0)
2587                         kmem_free(buf, drrs->drr_length);
2588                 return (err);
2589         }
2590         default:
2591                 return (SET_ERROR(EINVAL));
2592         }
2593 }
2594 
2595 /*
2596  * Commit the records to the pool.
2597  */
2598 static int
2599 receive_process_record(struct receive_writer_arg *rwa,
2600     struct receive_record_arg *rrd)
2601 {
2602         int err;
2603 
2604         /* Processing in order, therefore bytes_read should be increasing. */
2605         ASSERT3U(rrd->bytes_read, >=, rwa->bytes_read);
2606         rwa->bytes_read = rrd->bytes_read;
2607 
2608         switch (rrd->header.drr_type) {
2609         case DRR_OBJECT:
2610         {
2611                 struct drr_object *drro = &rrd->header.drr_u.drr_object;
2612                 err = receive_object(rwa, drro, rrd->payload);
2613                 kmem_free(rrd->payload, rrd->payload_size);
2614                 rrd->payload = NULL;
2615                 return (err);
2616         }
2617         case DRR_FREEOBJECTS:
2618         {
2619                 struct drr_freeobjects *drrfo =
2620                     &rrd->header.drr_u.drr_freeobjects;
2621                 return (receive_freeobjects(rwa, drrfo));
2622         }
2623         case DRR_WRITE:
2624         {
2625                 struct drr_write *drrw = &rrd->header.drr_u.drr_write;
2626                 err = receive_write(rwa, drrw, rrd->write_buf);
2627                 /* if receive_write() is successful, it consumes the arc_buf */
2628                 if (err != 0)
2629                         dmu_return_arcbuf(rrd->write_buf);
2630                 rrd->write_buf = NULL;
2631                 rrd->payload = NULL;
2632                 return (err);
2633         }
2634         case DRR_WRITE_BYREF:
2635         {
2636                 struct drr_write_byref *drrwbr =
2637                     &rrd->header.drr_u.drr_write_byref;
2638                 return (receive_write_byref(rwa, drrwbr));
2639         }
2640         case DRR_WRITE_EMBEDDED:
2641         {
2642                 struct drr_write_embedded *drrwe =
2643                     &rrd->header.drr_u.drr_write_embedded;
2644                 err = receive_write_embedded(rwa, drrwe, rrd->payload);
2645                 kmem_free(rrd->payload, rrd->payload_size);
2646                 rrd->payload = NULL;
2647                 return (err);
2648         }
2649         case DRR_FREE:
2650         {
2651                 struct drr_free *drrf = &rrd->header.drr_u.drr_free;
2652                 return (receive_free(rwa, drrf));
2653         }
2654         case DRR_SPILL:
2655         {
2656                 struct drr_spill *drrs = &rrd->header.drr_u.drr_spill;
2657                 err = receive_spill(rwa, drrs, rrd->payload);
2658                 kmem_free(rrd->payload, rrd->payload_size);
2659                 rrd->payload = NULL;
2660                 return (err);
2661         }
2662         default:
2663                 return (SET_ERROR(EINVAL));
2664         }
2665 }
2666 
2667 /*
2668  * dmu_recv_stream's worker thread; pull records off the queue, and then call
2669  * receive_process_record  When we're done, signal the main thread and exit.
2670  */
2671 static void
2672 receive_writer_thread(void *arg)
2673 {
2674         struct receive_writer_arg *rwa = arg;
2675         struct receive_record_arg *rrd;
2676         for (rrd = bqueue_dequeue(&rwa->q); !rrd->eos_marker;
2677             rrd = bqueue_dequeue(&rwa->q)) {
2678                 /*
2679                  * If there's an error, the main thread will stop putting things
2680                  * on the queue, but we need to clear everything in it before we
2681                  * can exit.
2682                  */
2683                 if (rwa->err == 0) {
2684                         rwa->err = receive_process_record(rwa, rrd);
2685                 } else if (rrd->write_buf != NULL) {
2686                         dmu_return_arcbuf(rrd->write_buf);
2687                         rrd->write_buf = NULL;
2688                         rrd->payload = NULL;
2689                 } else if (rrd->payload != NULL) {
2690                         kmem_free(rrd->payload, rrd->payload_size);
2691                         rrd->payload = NULL;
2692                 }
2693                 kmem_free(rrd, sizeof (*rrd));
2694         }
2695         kmem_free(rrd, sizeof (*rrd));
2696         mutex_enter(&rwa->mutex);
2697         rwa->done = B_TRUE;
2698         cv_signal(&rwa->cv);
2699         mutex_exit(&rwa->mutex);
2700 }
2701 
2702 static int
2703 resume_check(struct receive_arg *ra, nvlist_t *begin_nvl)
2704 {
2705         uint64_t val;
2706         objset_t *mos = dmu_objset_pool(ra->os)->dp_meta_objset;
2707         uint64_t dsobj = dmu_objset_id(ra->os);
2708         uint64_t resume_obj, resume_off;
2709 
2710         if (nvlist_lookup_uint64(begin_nvl,
2711             "resume_object", &resume_obj) != 0 ||
2712             nvlist_lookup_uint64(begin_nvl,
2713             "resume_offset", &resume_off) != 0) {
2714                 return (SET_ERROR(EINVAL));
2715         }
2716         VERIFY0(zap_lookup(mos, dsobj,
2717             DS_FIELD_RESUME_OBJECT, sizeof (val), 1, &val));
2718         if (resume_obj != val)
2719                 return (SET_ERROR(EINVAL));
2720         VERIFY0(zap_lookup(mos, dsobj,
2721             DS_FIELD_RESUME_OFFSET, sizeof (val), 1, &val));
2722         if (resume_off != val)
2723                 return (SET_ERROR(EINVAL));
2724 
2725         return (0);
2726 }
2727 
2728 /*
2729  * Read in the stream's records, one by one, and apply them to the pool.  There
2730  * are two threads involved; the thread that calls this function will spin up a
2731  * worker thread, read the records off the stream one by one, and issue
2732  * prefetches for any necessary indirect blocks.  It will then push the records
2733  * onto an internal blocking queue.  The worker thread will pull the records off
2734  * the queue, and actually write the data into the DMU.  This way, the worker
2735  * thread doesn't have to wait for reads to complete, since everything it needs
2736  * (the indirect blocks) will be prefetched.
2737  *
2738  * NB: callers *must* call dmu_recv_end() if this succeeds.
2739  */
2740 int
2741 dmu_recv_stream(dmu_recv_cookie_t *drc, vnode_t *vp, offset_t *voffp,
2742     int cleanup_fd, uint64_t *action_handlep)
2743 {
2744         int err = 0;
2745         struct receive_arg ra = { 0 };
2746         struct receive_writer_arg rwa = { 0 };
2747         int featureflags;
2748         nvlist_t *begin_nvl = NULL;
2749 
2750         ra.byteswap = drc->drc_byteswap;
2751         ra.cksum = drc->drc_cksum;
2752         ra.vp = vp;
2753         ra.voff = *voffp;
2754 
2755         if (dsl_dataset_is_zapified(drc->drc_ds)) {
2756                 (void) zap_lookup(drc->drc_ds->ds_dir->dd_pool->dp_meta_objset,
2757                     drc->drc_ds->ds_object, DS_FIELD_RESUME_BYTES,
2758                     sizeof (ra.bytes_read), 1, &ra.bytes_read);
2759         }
2760 
2761         objlist_create(&ra.ignore_objlist);
2762 
2763         /* these were verified in dmu_recv_begin */
2764         ASSERT3U(DMU_GET_STREAM_HDRTYPE(drc->drc_drrb->drr_versioninfo), ==,
2765             DMU_SUBSTREAM);
2766         ASSERT3U(drc->drc_drrb->drr_type, <, DMU_OST_NUMTYPES);
2767 
2768         /*
2769          * Open the objset we are modifying.
2770          */
2771         VERIFY0(dmu_objset_from_ds(drc->drc_ds, &ra.os));
2772 
2773         ASSERT(dsl_dataset_phys(drc->drc_ds)->ds_flags & DS_FLAG_INCONSISTENT);
2774 
2775         featureflags = DMU_GET_FEATUREFLAGS(drc->drc_drrb->drr_versioninfo);
2776 
2777         /* if this stream is dedup'ed, set up the avl tree for guid mapping */
2778         if (featureflags & DMU_BACKUP_FEATURE_DEDUP) {
2779                 minor_t minor;
2780 
2781                 if (cleanup_fd == -1) {
2782                         ra.err = SET_ERROR(EBADF);
2783                         goto out;
2784                 }
2785                 ra.err = zfs_onexit_fd_hold(cleanup_fd, &minor);
2786                 if (ra.err != 0) {
2787                         cleanup_fd = -1;
2788                         goto out;
2789                 }
2790 
2791                 if (*action_handlep == 0) {
2792                         rwa.guid_to_ds_map =
2793                             kmem_alloc(sizeof (avl_tree_t), KM_SLEEP);
2794                         avl_create(rwa.guid_to_ds_map, guid_compare,
2795                             sizeof (guid_map_entry_t),
2796                             offsetof(guid_map_entry_t, avlnode));
2797                         err = zfs_onexit_add_cb(minor,
2798                             free_guid_map_onexit, rwa.guid_to_ds_map,
2799                             action_handlep);
2800                         if (ra.err != 0)
2801                                 goto out;
2802                 } else {
2803                         err = zfs_onexit_cb_data(minor, *action_handlep,
2804                             (void **)&rwa.guid_to_ds_map);
2805                         if (ra.err != 0)
2806                                 goto out;
2807                 }
2808 
2809                 drc->drc_guid_to_ds_map = rwa.guid_to_ds_map;
2810         }
2811 
2812         uint32_t payloadlen = drc->drc_drr_begin->drr_payloadlen;
2813         void *payload = NULL;
2814         if (payloadlen != 0)
2815                 payload = kmem_alloc(payloadlen, KM_SLEEP);
2816 
2817         err = receive_read_payload_and_next_header(&ra, payloadlen, payload);
2818         if (err != 0) {
2819                 if (payloadlen != 0)
2820                         kmem_free(payload, payloadlen);
2821                 goto out;
2822         }
2823         if (payloadlen != 0) {
2824                 err = nvlist_unpack(payload, payloadlen, &begin_nvl, KM_SLEEP);
2825                 kmem_free(payload, payloadlen);
2826                 if (err != 0)
2827                         goto out;
2828         }
2829 
2830         if (featureflags & DMU_BACKUP_FEATURE_RESUMING) {
2831                 err = resume_check(&ra, begin_nvl);
2832                 if (err != 0)
2833                         goto out;
2834         }
2835 
2836         (void) bqueue_init(&rwa.q, zfs_recv_queue_length,
2837             offsetof(struct receive_record_arg, node));
2838         cv_init(&rwa.cv, NULL, CV_DEFAULT, NULL);
2839         mutex_init(&rwa.mutex, NULL, MUTEX_DEFAULT, NULL);
2840         rwa.os = ra.os;
2841         rwa.byteswap = drc->drc_byteswap;
2842         rwa.resumable = drc->drc_resumable;
2843 
2844         (void) thread_create(NULL, 0, receive_writer_thread, &rwa, 0, curproc,
2845             TS_RUN, minclsyspri);
2846         /*
2847          * We're reading rwa.err without locks, which is safe since we are the
2848          * only reader, and the worker thread is the only writer.  It's ok if we
2849          * miss a write for an iteration or two of the loop, since the writer
2850          * thread will keep freeing records we send it until we send it an eos
2851          * marker.
2852          *
2853          * We can leave this loop in 3 ways:  First, if rwa.err is
2854          * non-zero.  In that case, the writer thread will free the rrd we just
2855          * pushed.  Second, if  we're interrupted; in that case, either it's the
2856          * first loop and ra.rrd was never allocated, or it's later, and ra.rrd
2857          * has been handed off to the writer thread who will free it.  Finally,
2858          * if receive_read_record fails or we're at the end of the stream, then
2859          * we free ra.rrd and exit.
2860          */
2861         while (rwa.err == 0) {
2862                 if (issig(JUSTLOOKING) && issig(FORREAL)) {
2863                         err = SET_ERROR(EINTR);
2864                         break;
2865                 }
2866 
2867                 ASSERT3P(ra.rrd, ==, NULL);
2868                 ra.rrd = ra.next_rrd;
2869                 ra.next_rrd = NULL;
2870                 /* Allocates and loads header into ra.next_rrd */
2871                 err = receive_read_record(&ra);
2872 
2873                 if (ra.rrd->header.drr_type == DRR_END || err != 0) {
2874                         kmem_free(ra.rrd, sizeof (*ra.rrd));
2875                         ra.rrd = NULL;
2876                         break;
2877                 }
2878 
2879                 bqueue_enqueue(&rwa.q, ra.rrd,
2880                     sizeof (struct receive_record_arg) + ra.rrd->payload_size);
2881                 ra.rrd = NULL;
2882         }
2883         if (ra.next_rrd == NULL)
2884                 ra.next_rrd = kmem_zalloc(sizeof (*ra.next_rrd), KM_SLEEP);
2885         ra.next_rrd->eos_marker = B_TRUE;
2886         bqueue_enqueue(&rwa.q, ra.next_rrd, 1);
2887 
2888         mutex_enter(&rwa.mutex);
2889         while (!rwa.done) {
2890                 cv_wait(&rwa.cv, &rwa.mutex);
2891         }
2892         mutex_exit(&rwa.mutex);
2893 
2894         cv_destroy(&rwa.cv);
2895         mutex_destroy(&rwa.mutex);
2896         bqueue_destroy(&rwa.q);
2897         if (err == 0)
2898                 err = rwa.err;
2899 
2900 out:
2901         nvlist_free(begin_nvl);
2902         if ((featureflags & DMU_BACKUP_FEATURE_DEDUP) && (cleanup_fd != -1))
2903                 zfs_onexit_fd_rele(cleanup_fd);
2904 
2905         if (err != 0) {
2906                 /*
2907                  * Clean up references. If receive is not resumable,
2908                  * destroy what we created, so we don't leave it in
2909                  * the inconsistent state.
2910                  */
2911                 dmu_recv_cleanup_ds(drc);
2912         }
2913 
2914         *voffp = ra.voff;
2915         objlist_destroy(&ra.ignore_objlist);
2916         return (err);
2917 }
2918 
2919 static int
2920 dmu_recv_end_check(void *arg, dmu_tx_t *tx)
2921 {
2922         dmu_recv_cookie_t *drc = arg;
2923         dsl_pool_t *dp = dmu_tx_pool(tx);
2924         int error;
2925 
2926         ASSERT3P(drc->drc_ds->ds_owner, ==, dmu_recv_tag);
2927 
2928         if (!drc->drc_newfs) {
2929                 dsl_dataset_t *origin_head;
2930 
2931                 error = dsl_dataset_hold(dp, drc->drc_tofs, FTAG, &origin_head);
2932                 if (error != 0)
2933                         return (error);
2934                 if (drc->drc_force) {
2935                         /*
2936                          * We will destroy any snapshots in tofs (i.e. before
2937                          * origin_head) that are after the origin (which is
2938                          * the snap before drc_ds, because drc_ds can not
2939                          * have any snaps of its own).
2940                          */
2941                         uint64_t obj;
2942 
2943                         obj = dsl_dataset_phys(origin_head)->ds_prev_snap_obj;
2944                         while (obj !=
2945                             dsl_dataset_phys(drc->drc_ds)->ds_prev_snap_obj) {
2946                                 dsl_dataset_t *snap;
2947                                 error = dsl_dataset_hold_obj(dp, obj, FTAG,
2948                                     &snap);
2949                                 if (error != 0)
2950                                         break;
2951                                 if (snap->ds_dir != origin_head->ds_dir)
2952                                         error = SET_ERROR(EINVAL);
2953                                 if (error == 0)  {
2954                                         error = dsl_destroy_snapshot_check_impl(
2955                                             snap, B_FALSE);
2956                                 }
2957                                 obj = dsl_dataset_phys(snap)->ds_prev_snap_obj;
2958                                 dsl_dataset_rele(snap, FTAG);
2959                                 if (error != 0)
2960                                         break;
2961                         }
2962                         if (error != 0) {
2963                                 dsl_dataset_rele(origin_head, FTAG);
2964                                 return (error);
2965                         }
2966                 }
2967                 error = dsl_dataset_clone_swap_check_impl(drc->drc_ds,
2968                     origin_head, drc->drc_force, drc->drc_owner, tx);
2969                 if (error != 0) {
2970                         dsl_dataset_rele(origin_head, FTAG);
2971                         return (error);
2972                 }
2973                 error = dsl_dataset_snapshot_check_impl(origin_head,
2974                     drc->drc_tosnap, tx, B_TRUE, 1, drc->drc_cred);
2975                 dsl_dataset_rele(origin_head, FTAG);
2976                 if (error != 0)
2977                         return (error);
2978 
2979                 error = dsl_destroy_head_check_impl(drc->drc_ds, 1);
2980         } else {
2981                 error = dsl_dataset_snapshot_check_impl(drc->drc_ds,
2982                     drc->drc_tosnap, tx, B_TRUE, 1, drc->drc_cred);
2983         }
2984         return (error);
2985 }
2986 
2987 static void
2988 dmu_recv_end_sync(void *arg, dmu_tx_t *tx)
2989 {
2990         dmu_recv_cookie_t *drc = arg;
2991         dsl_pool_t *dp = dmu_tx_pool(tx);
2992 
2993         spa_history_log_internal_ds(drc->drc_ds, "finish receiving",
2994             tx, "snap=%s", drc->drc_tosnap);
2995 
2996         if (!drc->drc_newfs) {
2997                 dsl_dataset_t *origin_head;
2998 
2999                 VERIFY0(dsl_dataset_hold(dp, drc->drc_tofs, FTAG,
3000                     &origin_head));
3001 
3002                 if (drc->drc_force) {
3003                         /*
3004                          * Destroy any snapshots of drc_tofs (origin_head)
3005                          * after the origin (the snap before drc_ds).
3006                          */
3007                         uint64_t obj;
3008 
3009                         obj = dsl_dataset_phys(origin_head)->ds_prev_snap_obj;
3010                         while (obj !=
3011                             dsl_dataset_phys(drc->drc_ds)->ds_prev_snap_obj) {
3012                                 dsl_dataset_t *snap;
3013                                 VERIFY0(dsl_dataset_hold_obj(dp, obj, FTAG,
3014                                     &snap));
3015                                 ASSERT3P(snap->ds_dir, ==, origin_head->ds_dir);
3016                                 obj = dsl_dataset_phys(snap)->ds_prev_snap_obj;
3017                                 dsl_destroy_snapshot_sync_impl(snap,
3018                                     B_FALSE, tx);
3019                                 dsl_dataset_rele(snap, FTAG);
3020                         }
3021                 }
3022                 VERIFY3P(drc->drc_ds->ds_prev, ==,
3023                     origin_head->ds_prev);
3024 
3025                 dsl_dataset_clone_swap_sync_impl(drc->drc_ds,
3026                     origin_head, tx);
3027                 dsl_dataset_snapshot_sync_impl(origin_head,
3028                     drc->drc_tosnap, tx);
3029 
3030                 /* set snapshot's creation time and guid */
3031                 dmu_buf_will_dirty(origin_head->ds_prev->ds_dbuf, tx);
3032                 dsl_dataset_phys(origin_head->ds_prev)->ds_creation_time =
3033                     drc->drc_drrb->drr_creation_time;
3034                 dsl_dataset_phys(origin_head->ds_prev)->ds_guid =
3035                     drc->drc_drrb->drr_toguid;
3036                 dsl_dataset_phys(origin_head->ds_prev)->ds_flags &=
3037                     ~DS_FLAG_INCONSISTENT;
3038 
3039                 dmu_buf_will_dirty(origin_head->ds_dbuf, tx);
3040                 dsl_dataset_phys(origin_head)->ds_flags &=
3041                     ~DS_FLAG_INCONSISTENT;
3042 
3043                 dsl_dataset_rele(origin_head, FTAG);
3044                 dsl_destroy_head_sync_impl(drc->drc_ds, tx);
3045 
3046                 if (drc->drc_owner != NULL)
3047                         VERIFY3P(origin_head->ds_owner, ==, drc->drc_owner);
3048         } else {
3049                 dsl_dataset_t *ds = drc->drc_ds;
3050 
3051                 dsl_dataset_snapshot_sync_impl(ds, drc->drc_tosnap, tx);
3052 
3053                 /* set snapshot's creation time and guid */
3054                 dmu_buf_will_dirty(ds->ds_prev->ds_dbuf, tx);
3055                 dsl_dataset_phys(ds->ds_prev)->ds_creation_time =
3056                     drc->drc_drrb->drr_creation_time;
3057                 dsl_dataset_phys(ds->ds_prev)->ds_guid =
3058                     drc->drc_drrb->drr_toguid;
3059                 dsl_dataset_phys(ds->ds_prev)->ds_flags &=
3060                     ~DS_FLAG_INCONSISTENT;
3061 
3062                 dmu_buf_will_dirty(ds->ds_dbuf, tx);
3063                 dsl_dataset_phys(ds)->ds_flags &= ~DS_FLAG_INCONSISTENT;
3064                 if (dsl_dataset_has_resume_receive_state(ds)) {
3065                         (void) zap_remove(dp->dp_meta_objset, ds->ds_object,
3066                             DS_FIELD_RESUME_FROMGUID, tx);
3067                         (void) zap_remove(dp->dp_meta_objset, ds->ds_object,
3068                             DS_FIELD_RESUME_OBJECT, tx);
3069                         (void) zap_remove(dp->dp_meta_objset, ds->ds_object,
3070                             DS_FIELD_RESUME_OFFSET, tx);
3071                         (void) zap_remove(dp->dp_meta_objset, ds->ds_object,
3072                             DS_FIELD_RESUME_BYTES, tx);
3073                         (void) zap_remove(dp->dp_meta_objset, ds->ds_object,
3074                             DS_FIELD_RESUME_TOGUID, tx);
3075                         (void) zap_remove(dp->dp_meta_objset, ds->ds_object,
3076                             DS_FIELD_RESUME_TONAME, tx);
3077                 }
3078         }
3079         drc->drc_newsnapobj = dsl_dataset_phys(drc->drc_ds)->ds_prev_snap_obj;
3080         /*
3081          * Release the hold from dmu_recv_begin.  This must be done before
3082          * we return to open context, so that when we free the dataset's dnode,
3083          * we can evict its bonus buffer.
3084          */
3085         dsl_dataset_disown(drc->drc_ds, dmu_recv_tag);
3086         drc->drc_ds = NULL;
3087 }
3088 
3089 static int
3090 add_ds_to_guidmap(const char *name, avl_tree_t *guid_map, uint64_t snapobj)
3091 {
3092         dsl_pool_t *dp;
3093         dsl_dataset_t *snapds;
3094         guid_map_entry_t *gmep;
3095         int err;
3096 
3097         ASSERT(guid_map != NULL);
3098 
3099         err = dsl_pool_hold(name, FTAG, &dp);
3100         if (err != 0)
3101                 return (err);
3102         gmep = kmem_alloc(sizeof (*gmep), KM_SLEEP);
3103         err = dsl_dataset_hold_obj(dp, snapobj, gmep, &snapds);
3104         if (err == 0) {
3105                 gmep->guid = dsl_dataset_phys(snapds)->ds_guid;
3106                 gmep->gme_ds = snapds;
3107                 avl_add(guid_map, gmep);
3108                 dsl_dataset_long_hold(snapds, gmep);
3109         } else {
3110                 kmem_free(gmep, sizeof (*gmep));
3111         }
3112 
3113         dsl_pool_rele(dp, FTAG);
3114         return (err);
3115 }
3116 
3117 static int dmu_recv_end_modified_blocks = 3;
3118 
3119 static int
3120 dmu_recv_existing_end(dmu_recv_cookie_t *drc)
3121 {
3122         int error;
3123 
3124 #ifdef _KERNEL
3125         /*
3126          * We will be destroying the ds; make sure its origin is unmounted if
3127          * necessary.
3128          */
3129         char name[ZFS_MAX_DATASET_NAME_LEN];
3130         dsl_dataset_name(drc->drc_ds, name);
3131         zfs_destroy_unmount_origin(name);
3132 #endif
3133 
3134         error = dsl_sync_task(drc->drc_tofs,
3135             dmu_recv_end_check, dmu_recv_end_sync, drc,
3136             dmu_recv_end_modified_blocks, ZFS_SPACE_CHECK_NORMAL);
3137 
3138         if (error != 0)
3139                 dmu_recv_cleanup_ds(drc);
3140         return (error);
3141 }
3142 
3143 static int
3144 dmu_recv_new_end(dmu_recv_cookie_t *drc)
3145 {
3146         int error;
3147 
3148         error = dsl_sync_task(drc->drc_tofs,
3149             dmu_recv_end_check, dmu_recv_end_sync, drc,
3150             dmu_recv_end_modified_blocks, ZFS_SPACE_CHECK_NORMAL);
3151 
3152         if (error != 0) {
3153                 dmu_recv_cleanup_ds(drc);
3154         } else if (drc->drc_guid_to_ds_map != NULL) {
3155                 (void) add_ds_to_guidmap(drc->drc_tofs,
3156                     drc->drc_guid_to_ds_map,
3157                     drc->drc_newsnapobj);
3158         }
3159         return (error);
3160 }
3161 
3162 int
3163 dmu_recv_end(dmu_recv_cookie_t *drc, void *owner)
3164 {
3165         drc->drc_owner = owner;
3166 
3167         if (drc->drc_newfs)
3168                 return (dmu_recv_new_end(drc));
3169         else
3170                 return (dmu_recv_existing_end(drc));
3171 }
3172 
3173 /*
3174  * Return TRUE if this objset is currently being received into.
3175  */
3176 boolean_t
3177 dmu_objset_is_receiving(objset_t *os)
3178 {
3179         return (os->os_dsl_dataset != NULL &&
3180             os->os_dsl_dataset->ds_owner == dmu_recv_tag);
3181 }