--- a/usr/src/uts/common/Makefile.files	Fri Sep 15 11:16:46 2006 -0700
+++ b/usr/src/uts/common/Makefile.files	Fri Sep 15 11:21:46 2006 -0700
@@ -870,6 +870,7 @@
 	bplist.o		\
 	dbuf.o			\
 	dmu.o			\
+	dmu_send.o		\
 	dmu_object.o		\
 	dmu_objset.o		\
 	dmu_traverse.o		\

--- a/usr/src/uts/common/fs/zfs/dmu.c	Fri Sep 15 11:16:46 2006 -0700
+++ b/usr/src/uts/common/fs/zfs/dmu.c	Fri Sep 15 11:21:46 2006 -0700
@@ -560,926 +560,6 @@
 }
 #endif
 
-/*
- * XXX move send/recv stuff to its own new file!
- */
-
-struct backuparg {
-	dmu_replay_record_t *drr;
-	vnode_t *vp;
-	objset_t *os;
-	zio_cksum_t zc;
-	int err;
-};
-
-static int
-dump_bytes(struct backuparg *ba, void *buf, int len)
-{
-	ssize_t resid; /* have to get resid to get detailed errno */
-	ASSERT3U(len % 8, ==, 0);
-
-	fletcher_4_incremental_native(buf, len, &ba->zc);
-	ba->err = vn_rdwr(UIO_WRITE, ba->vp,
-	    (caddr_t)buf, len,
-	    0, UIO_SYSSPACE, FAPPEND, RLIM64_INFINITY, CRED(), &resid);
-	return (ba->err);
-}
-
-static int
-dump_free(struct backuparg *ba, uint64_t object, uint64_t offset,
-    uint64_t length)
-{
-	/* write a FREE record */
-	bzero(ba->drr, sizeof (dmu_replay_record_t));
-	ba->drr->drr_type = DRR_FREE;
-	ba->drr->drr_u.drr_free.drr_object = object;
-	ba->drr->drr_u.drr_free.drr_offset = offset;
-	ba->drr->drr_u.drr_free.drr_length = length;
-
-	if (dump_bytes(ba, ba->drr, sizeof (dmu_replay_record_t)))
-		return (EINTR);
-	return (0);
-}
-
-static int
-dump_data(struct backuparg *ba, dmu_object_type_t type,
-    uint64_t object, uint64_t offset, int blksz, void *data)
-{
-	/* write a DATA record */
-	bzero(ba->drr, sizeof (dmu_replay_record_t));
-	ba->drr->drr_type = DRR_WRITE;
-	ba->drr->drr_u.drr_write.drr_object = object;
-	ba->drr->drr_u.drr_write.drr_type = type;
-	ba->drr->drr_u.drr_write.drr_offset = offset;
-	ba->drr->drr_u.drr_write.drr_length = blksz;
-
-	if (dump_bytes(ba, ba->drr, sizeof (dmu_replay_record_t)))
-		return (EINTR);
-	if (dump_bytes(ba, data, blksz))
-		return (EINTR);
-	return (0);
-}
-
-static int
-dump_freeobjects(struct backuparg *ba, uint64_t firstobj, uint64_t numobjs)
-{
-	/* write a FREEOBJECTS record */
-	bzero(ba->drr, sizeof (dmu_replay_record_t));
-	ba->drr->drr_type = DRR_FREEOBJECTS;
-	ba->drr->drr_u.drr_freeobjects.drr_firstobj = firstobj;
-	ba->drr->drr_u.drr_freeobjects.drr_numobjs = numobjs;
-
-	if (dump_bytes(ba, ba->drr, sizeof (dmu_replay_record_t)))
-		return (EINTR);
-	return (0);
-}
-
-static int
-dump_dnode(struct backuparg *ba, uint64_t object, dnode_phys_t *dnp)
-{
-	if (dnp == NULL || dnp->dn_type == DMU_OT_NONE)
-		return (dump_freeobjects(ba, object, 1));
-
-	/* write an OBJECT record */
-	bzero(ba->drr, sizeof (dmu_replay_record_t));
-	ba->drr->drr_type = DRR_OBJECT;
-	ba->drr->drr_u.drr_object.drr_object = object;
-	ba->drr->drr_u.drr_object.drr_type = dnp->dn_type;
-	ba->drr->drr_u.drr_object.drr_bonustype = dnp->dn_bonustype;
-	ba->drr->drr_u.drr_object.drr_blksz =
-	    dnp->dn_datablkszsec << SPA_MINBLOCKSHIFT;
-	ba->drr->drr_u.drr_object.drr_bonuslen = dnp->dn_bonuslen;
-	ba->drr->drr_u.drr_object.drr_checksum = dnp->dn_checksum;
-	ba->drr->drr_u.drr_object.drr_compress = dnp->dn_compress;
-
-	if (dump_bytes(ba, ba->drr, sizeof (dmu_replay_record_t)))
-		return (EINTR);
-
-	if (dump_bytes(ba, DN_BONUS(dnp), P2ROUNDUP(dnp->dn_bonuslen, 8)))
-		return (EINTR);
-
-	/* free anything past the end of the file */
-	if (dump_free(ba, object, (dnp->dn_maxblkid + 1) *
-	    (dnp->dn_datablkszsec << SPA_MINBLOCKSHIFT), -1ULL))
-		return (EINTR);
-	if (ba->err)
-		return (EINTR);
-	return (0);
-}
-
-#define	BP_SPAN(dnp, level) \
-	(((uint64_t)dnp->dn_datablkszsec) << (SPA_MINBLOCKSHIFT + \
-	(level) * (dnp->dn_indblkshift - SPA_BLKPTRSHIFT)))
-
-static int
-backup_cb(traverse_blk_cache_t *bc, spa_t *spa, void *arg)
-{
-	struct backuparg *ba = arg;
-	uint64_t object = bc->bc_bookmark.zb_object;
-	int level = bc->bc_bookmark.zb_level;
-	uint64_t blkid = bc->bc_bookmark.zb_blkid;
-	blkptr_t *bp = bc->bc_blkptr.blk_birth ? &bc->bc_blkptr : NULL;
-	dmu_object_type_t type = bp ? BP_GET_TYPE(bp) : DMU_OT_NONE;
-	void *data = bc->bc_data;
-	int err = 0;
-
-	if (issig(JUSTLOOKING) && issig(FORREAL))
-		return (EINTR);
-
-	ASSERT(data || bp == NULL);
-
-	if (bp == NULL && object == 0) {
-		uint64_t span = BP_SPAN(bc->bc_dnode, level);
-		uint64_t dnobj = (blkid * span) >> DNODE_SHIFT;
-		err = dump_freeobjects(ba, dnobj, span >> DNODE_SHIFT);
-	} else if (bp == NULL) {
-		uint64_t span = BP_SPAN(bc->bc_dnode, level);
-		err = dump_free(ba, object, blkid * span, span);
-	} else if (data && level == 0 && type == DMU_OT_DNODE) {
-		dnode_phys_t *blk = data;
-		int i;
-		int blksz = BP_GET_LSIZE(bp);
-
-		for (i = 0; i < blksz >> DNODE_SHIFT; i++) {
-			uint64_t dnobj =
-			    (blkid << (DNODE_BLOCK_SHIFT - DNODE_SHIFT)) + i;
-			err = dump_dnode(ba, dnobj, blk+i);
-			if (err)
-				break;
-		}
-	} else if (level == 0 &&
-	    type != DMU_OT_DNODE && type != DMU_OT_OBJSET) {
-		int blksz = BP_GET_LSIZE(bp);
-		if (data == NULL) {
-			uint32_t aflags = ARC_WAIT;
-			arc_buf_t *abuf;
-			zbookmark_t zb;
-
-			zb.zb_objset = ba->os->os->os_dsl_dataset->ds_object;
-			zb.zb_object = object;
-			zb.zb_level = level;
-			zb.zb_blkid = blkid;
-			(void) arc_read(NULL, spa, bp,
-			    dmu_ot[type].ot_byteswap, arc_getbuf_func, &abuf,
-			    ZIO_PRIORITY_ASYNC_READ, ZIO_FLAG_MUSTSUCCEED,
-			    &aflags, &zb);
-
-			if (abuf) {
-				err = dump_data(ba, type, object, blkid * blksz,
-				    blksz, abuf->b_data);
-				(void) arc_buf_remove_ref(abuf, &abuf);
-			}
-		} else {
-			err = dump_data(ba, type, object, blkid * blksz,
-			    blksz, data);
-		}
-	}
-
-	ASSERT(err == 0 || err == EINTR);
-	return (err);
-}
-
-int
-dmu_sendbackup(objset_t *tosnap, objset_t *fromsnap, vnode_t *vp)
-{
-	dsl_dataset_t *ds = tosnap->os->os_dsl_dataset;
-	dsl_dataset_t *fromds = fromsnap ? fromsnap->os->os_dsl_dataset : NULL;
-	dmu_replay_record_t *drr;
-	struct backuparg ba;
-	int err;
-
-	/* tosnap must be a snapshot */
-	if (ds->ds_phys->ds_next_snap_obj == 0)
-		return (EINVAL);
-
-	/* fromsnap must be an earlier snapshot from the same fs as tosnap */
-	if (fromds && (ds->ds_dir != fromds->ds_dir ||
-	    fromds->ds_phys->ds_creation_txg >=
-	    ds->ds_phys->ds_creation_txg))
-		return (EXDEV);
-
-	drr = kmem_zalloc(sizeof (dmu_replay_record_t), KM_SLEEP);
-	drr->drr_type = DRR_BEGIN;
-	drr->drr_u.drr_begin.drr_magic = DMU_BACKUP_MAGIC;
-	drr->drr_u.drr_begin.drr_version = DMU_BACKUP_VERSION;
-	drr->drr_u.drr_begin.drr_creation_time =
-	    ds->ds_phys->ds_creation_time;
-	drr->drr_u.drr_begin.drr_type = tosnap->os->os_phys->os_type;
-	drr->drr_u.drr_begin.drr_toguid = ds->ds_phys->ds_guid;
-	if (fromds)
-		drr->drr_u.drr_begin.drr_fromguid = fromds->ds_phys->ds_guid;
-	dsl_dataset_name(ds, drr->drr_u.drr_begin.drr_toname);
-
-	ba.drr = drr;
-	ba.vp = vp;
-	ba.os = tosnap;
-	ZIO_SET_CHECKSUM(&ba.zc, 0, 0, 0, 0);
-
-	if (dump_bytes(&ba, drr, sizeof (dmu_replay_record_t))) {
-		kmem_free(drr, sizeof (dmu_replay_record_t));
-		return (ba.err);
-	}
-
-	err = traverse_dsl_dataset(ds,
-	    fromds ? fromds->ds_phys->ds_creation_txg : 0,
-	    ADVANCE_PRE | ADVANCE_HOLES | ADVANCE_DATA | ADVANCE_NOLOCK,
-	    backup_cb, &ba);
-
-	if (err) {
-		if (err == EINTR && ba.err)
-			err = ba.err;
-		return (err);
-	}
-
-	bzero(drr, sizeof (dmu_replay_record_t));
-	drr->drr_type = DRR_END;
-	drr->drr_u.drr_end.drr_checksum = ba.zc;
-
-	if (dump_bytes(&ba, drr, sizeof (dmu_replay_record_t)))
-		return (ba.err);
-
-	kmem_free(drr, sizeof (dmu_replay_record_t));
-
-	return (0);
-}
-
-struct restorearg {
-	int err;
-	int byteswap;
-	vnode_t *vp;
-	char *buf;
-	uint64_t voff;
-	int buflen; /* number of valid bytes in buf */
-	int bufoff; /* next offset to read */
-	int bufsize; /* amount of memory allocated for buf */
-	zio_cksum_t zc;
-};
-
-/* ARGSUSED */
-static int
-replay_incremental_check(void *arg1, void *arg2, dmu_tx_t *tx)
-{
-	dsl_dataset_t *ds = arg1;
-	struct drr_begin *drrb = arg2;
-	const char *snapname;
-	int err;
-	uint64_t val;
-
-	/* must already be a snapshot of this fs */
-	if (ds->ds_phys->ds_prev_snap_obj == 0)
-		return (ENODEV);
-
-	/* most recent snapshot must match fromguid */
-	if (ds->ds_prev->ds_phys->ds_guid != drrb->drr_fromguid)
-		return (ENODEV);
-	/* must not have any changes since most recent snapshot */
-	if (ds->ds_phys->ds_bp.blk_birth >
-	    ds->ds_prev->ds_phys->ds_creation_txg)
-		return (ETXTBSY);
-
-	/* new snapshot name must not exist */
-	snapname = strrchr(drrb->drr_toname, '@');
-	if (snapname == NULL)
-		return (EEXIST);
-
-	snapname++;
-	err = zap_lookup(ds->ds_dir->dd_pool->dp_meta_objset,
-	    ds->ds_phys->ds_snapnames_zapobj, snapname, 8, 1, &val);
-	if (err == 0)
-		return (EEXIST);
-	if (err != ENOENT)
-		return (err);
-
-	return (0);
-}
-
-/* ARGSUSED */
-static void
-replay_incremental_sync(void *arg1, void *arg2, dmu_tx_t *tx)
-{
-	dsl_dataset_t *ds = arg1;
-	dmu_buf_will_dirty(ds->ds_dbuf, tx);
-	ds->ds_phys->ds_flags |= DS_FLAG_INCONSISTENT;
-}
-
-/* ARGSUSED */
-static int
-replay_full_check(void *arg1, void *arg2, dmu_tx_t *tx)
-{
-	dsl_dir_t *dd = arg1;
-	struct drr_begin *drrb = arg2;
-	objset_t *mos = dd->dd_pool->dp_meta_objset;
-	char *cp;
-	uint64_t val;
-	int err;
-
-	cp = strchr(drrb->drr_toname, '@');
-	*cp = '\0';
-	err = zap_lookup(mos, dd->dd_phys->dd_child_dir_zapobj,
-	    strrchr(drrb->drr_toname, '/') + 1,
-	    sizeof (uint64_t), 1, &val);
-	*cp = '@';
-
-	if (err != ENOENT)
-		return (err ? err : EEXIST);
-
-	return (0);
-}
-
-static void
-replay_full_sync(void *arg1, void *arg2, dmu_tx_t *tx)
-{
-	dsl_dir_t *dd = arg1;
-	struct drr_begin *drrb = arg2;
-	char *cp;
-	dsl_dataset_t *ds;
-	uint64_t dsobj;
-
-	cp = strchr(drrb->drr_toname, '@');
-	*cp = '\0';
-	dsobj = dsl_dataset_create_sync(dd, strrchr(drrb->drr_toname, '/') + 1,
-	    NULL, tx);
-	*cp = '@';
-
-	VERIFY(0 == dsl_dataset_open_obj(dd->dd_pool, dsobj, NULL,
-	    DS_MODE_EXCLUSIVE, FTAG, &ds));
-
-	(void) dmu_objset_create_impl(dsl_dataset_get_spa(ds),
-	    ds, drrb->drr_type, tx);
-
-	dmu_buf_will_dirty(ds->ds_dbuf, tx);
-	ds->ds_phys->ds_flags |= DS_FLAG_INCONSISTENT;
-
-	dsl_dataset_close(ds, DS_MODE_EXCLUSIVE, FTAG);
-}
-
-static int
-replay_end_check(void *arg1, void *arg2, dmu_tx_t *tx)
-{
-	objset_t *os = arg1;
-	struct drr_begin *drrb = arg2;
-	char *snapname;
-
-	/* XXX verify that drr_toname is in dd */
-
-	snapname = strchr(drrb->drr_toname, '@');
-	if (snapname == NULL)
-		return (EINVAL);
-	snapname++;
-
-	return (dsl_dataset_snapshot_check(os, snapname, tx));
-}
-
-static void
-replay_end_sync(void *arg1, void *arg2, dmu_tx_t *tx)
-{
-	objset_t *os = arg1;
-	struct drr_begin *drrb = arg2;
-	char *snapname;
-	dsl_dataset_t *ds, *hds;
-
-	snapname = strchr(drrb->drr_toname, '@') + 1;
-
-	dsl_dataset_snapshot_sync(os, snapname, tx);
-
-	/* set snapshot's creation time and guid */
-	hds = os->os->os_dsl_dataset;
-	VERIFY(0 == dsl_dataset_open_obj(hds->ds_dir->dd_pool,
-	    hds->ds_phys->ds_prev_snap_obj, NULL,
-	    DS_MODE_PRIMARY | DS_MODE_READONLY | DS_MODE_INCONSISTENT,
-	    FTAG, &ds));
-
-	dmu_buf_will_dirty(ds->ds_dbuf, tx);
-	ds->ds_phys->ds_creation_time = drrb->drr_creation_time;
-	ds->ds_phys->ds_guid = drrb->drr_toguid;
-	ds->ds_phys->ds_flags &= ~DS_FLAG_INCONSISTENT;
-
-	dsl_dataset_close(ds, DS_MODE_PRIMARY, FTAG);
-
-	dmu_buf_will_dirty(hds->ds_dbuf, tx);
-	hds->ds_phys->ds_flags &= ~DS_FLAG_INCONSISTENT;
-}
-
-void *
-restore_read(struct restorearg *ra, int len)
-{
-	void *rv;
-
-	/* some things will require 8-byte alignment, so everything must */
-	ASSERT3U(len % 8, ==, 0);
-
-	while (ra->buflen - ra->bufoff < len) {
-		ssize_t resid;
-		int leftover = ra->buflen - ra->bufoff;
-
-		(void) memmove(ra->buf, ra->buf + ra->bufoff, leftover);
-		ra->err = vn_rdwr(UIO_READ, ra->vp,
-		    (caddr_t)ra->buf + leftover, ra->bufsize - leftover,
-		    ra->voff, UIO_SYSSPACE, FAPPEND,
-		    RLIM64_INFINITY, CRED(), &resid);
-
-		ra->voff += ra->bufsize - leftover - resid;
-		ra->buflen = ra->bufsize - resid;
-		ra->bufoff = 0;
-		if (resid == ra->bufsize - leftover)
-			ra->err = EINVAL;
-		if (ra->err)
-			return (NULL);
-		/* Could compute checksum here? */
-	}
-
-	ASSERT3U(ra->bufoff % 8, ==, 0);
-	ASSERT3U(ra->buflen - ra->bufoff, >=, len);
-	rv = ra->buf + ra->bufoff;
-	ra->bufoff += len;
-	if (ra->byteswap)
-		fletcher_4_incremental_byteswap(rv, len, &ra->zc);
-	else
-		fletcher_4_incremental_native(rv, len, &ra->zc);
-	return (rv);
-}
-
-static void
-backup_byteswap(dmu_replay_record_t *drr)
-{
-#define	DO64(X) (drr->drr_u.X = BSWAP_64(drr->drr_u.X))
-#define	DO32(X) (drr->drr_u.X = BSWAP_32(drr->drr_u.X))
-	drr->drr_type = BSWAP_32(drr->drr_type);
-	switch (drr->drr_type) {
-	case DRR_BEGIN:
-		DO64(drr_begin.drr_magic);
-		DO64(drr_begin.drr_version);
-		DO64(drr_begin.drr_creation_time);
-		DO32(drr_begin.drr_type);
-		DO64(drr_begin.drr_toguid);
-		DO64(drr_begin.drr_fromguid);
-		break;
-	case DRR_OBJECT:
-		DO64(drr_object.drr_object);
-		/* DO64(drr_object.drr_allocation_txg); */
-		DO32(drr_object.drr_type);
-		DO32(drr_object.drr_bonustype);
-		DO32(drr_object.drr_blksz);
-		DO32(drr_object.drr_bonuslen);
-		break;
-	case DRR_FREEOBJECTS:
-		DO64(drr_freeobjects.drr_firstobj);
-		DO64(drr_freeobjects.drr_numobjs);
-		break;
-	case DRR_WRITE:
-		DO64(drr_write.drr_object);
-		DO32(drr_write.drr_type);
-		DO64(drr_write.drr_offset);
-		DO64(drr_write.drr_length);
-		break;
-	case DRR_FREE:
-		DO64(drr_free.drr_object);
-		DO64(drr_free.drr_offset);
-		DO64(drr_free.drr_length);
-		break;
-	case DRR_END:
-		DO64(drr_end.drr_checksum.zc_word[0]);
-		DO64(drr_end.drr_checksum.zc_word[1]);
-		DO64(drr_end.drr_checksum.zc_word[2]);
-		DO64(drr_end.drr_checksum.zc_word[3]);
-		break;
-	}
-#undef DO64
-#undef DO32
-}
-
-static int
-restore_object(struct restorearg *ra, objset_t *os, struct drr_object *drro)
-{
-	int err;
-	dmu_tx_t *tx;
-
-	err = dmu_object_info(os, drro->drr_object, NULL);
-
-	if (err != 0 && err != ENOENT)
-		return (EINVAL);
-
-	if (drro->drr_type == DMU_OT_NONE ||
-	    drro->drr_type >= DMU_OT_NUMTYPES ||
-	    drro->drr_bonustype >= DMU_OT_NUMTYPES ||
-	    drro->drr_checksum >= ZIO_CHECKSUM_FUNCTIONS ||
-	    drro->drr_compress >= ZIO_COMPRESS_FUNCTIONS ||
-	    P2PHASE(drro->drr_blksz, SPA_MINBLOCKSIZE) ||
-	    drro->drr_blksz < SPA_MINBLOCKSIZE ||
-	    drro->drr_blksz > SPA_MAXBLOCKSIZE ||
-	    drro->drr_bonuslen > DN_MAX_BONUSLEN) {
-		return (EINVAL);
-	}
-
-	tx = dmu_tx_create(os);
-
-	if (err == ENOENT) {
-		/* currently free, want to be allocated */
-		dmu_tx_hold_bonus(tx, DMU_NEW_OBJECT);
-		dmu_tx_hold_write(tx, DMU_NEW_OBJECT, 0, 1);
-		err = dmu_tx_assign(tx, TXG_WAIT);
-		if (err) {
-			dmu_tx_abort(tx);
-			return (err);
-		}
-		err = dmu_object_claim(os, drro->drr_object,
-		    drro->drr_type, drro->drr_blksz,
-		    drro->drr_bonustype, drro->drr_bonuslen, tx);
-	} else {
-		/* currently allocated, want to be allocated */
-		dmu_tx_hold_bonus(tx, drro->drr_object);
-		/*
-		 * We may change blocksize, so need to
-		 * hold_write
-		 */
-		dmu_tx_hold_write(tx, drro->drr_object, 0, 1);
-		err = dmu_tx_assign(tx, TXG_WAIT);
-		if (err) {
-			dmu_tx_abort(tx);
-			return (err);
-		}
-
-		err = dmu_object_reclaim(os, drro->drr_object,
-		    drro->drr_type, drro->drr_blksz,
-		    drro->drr_bonustype, drro->drr_bonuslen, tx);
-	}
-	if (err) {
-		dmu_tx_commit(tx);
-		return (EINVAL);
-	}
-
-	dmu_object_set_checksum(os, drro->drr_object, drro->drr_checksum, tx);
-	dmu_object_set_compress(os, drro->drr_object, drro->drr_compress, tx);
-
-	if (drro->drr_bonuslen) {
-		dmu_buf_t *db;
-		void *data;
-		VERIFY(0 == dmu_bonus_hold(os, drro->drr_object, FTAG, &db));
-		dmu_buf_will_dirty(db, tx);
-
-		ASSERT3U(db->db_size, ==, drro->drr_bonuslen);
-		data = restore_read(ra, P2ROUNDUP(db->db_size, 8));
-		if (data == NULL) {
-			dmu_tx_commit(tx);
-			return (ra->err);
-		}
-		bcopy(data, db->db_data, db->db_size);
-		if (ra->byteswap) {
-			dmu_ot[drro->drr_bonustype].ot_byteswap(db->db_data,
-			    drro->drr_bonuslen);
-		}
-		dmu_buf_rele(db, FTAG);
-	}
-	dmu_tx_commit(tx);
-	return (0);
-}
-
-/* ARGSUSED */
-static int
-restore_freeobjects(struct restorearg *ra, objset_t *os,
-    struct drr_freeobjects *drrfo)
-{
-	uint64_t obj;
-
-	if (drrfo->drr_firstobj + drrfo->drr_numobjs < drrfo->drr_firstobj)
-		return (EINVAL);
-
-	for (obj = drrfo->drr_firstobj;
-	    obj < drrfo->drr_firstobj + drrfo->drr_numobjs; obj++) {
-		dmu_tx_t *tx;
-		int err;
-
-		if (dmu_object_info(os, obj, NULL) != 0)
-			continue;
-
-		tx = dmu_tx_create(os);
-		dmu_tx_hold_bonus(tx, obj);
-		err = dmu_tx_assign(tx, TXG_WAIT);
-		if (err) {
-			dmu_tx_abort(tx);
-			return (err);
-		}
-		err = dmu_object_free(os, obj, tx);
-		dmu_tx_commit(tx);
-		if (err && err != ENOENT)
-			return (EINVAL);
-	}
-	return (0);
-}
-
-static int
-restore_write(struct restorearg *ra, objset_t *os,
-    struct drr_write *drrw)
-{
-	dmu_tx_t *tx;
-	void *data;
-	int err;
-
-	if (drrw->drr_offset + drrw->drr_length < drrw->drr_offset ||
-	    drrw->drr_type >= DMU_OT_NUMTYPES)
-		return (EINVAL);
-
-	data = restore_read(ra, drrw->drr_length);
-	if (data == NULL)
-		return (ra->err);
-
-	if (dmu_object_info(os, drrw->drr_object, NULL) != 0)
-		return (EINVAL);
-
-	tx = dmu_tx_create(os);
-
-	dmu_tx_hold_write(tx, drrw->drr_object,
-	    drrw->drr_offset, drrw->drr_length);
-	err = dmu_tx_assign(tx, TXG_WAIT);
-	if (err) {
-		dmu_tx_abort(tx);
-		return (err);
-	}
-	if (ra->byteswap)
-		dmu_ot[drrw->drr_type].ot_byteswap(data, drrw->drr_length);
-	dmu_write(os, drrw->drr_object,
-	    drrw->drr_offset, drrw->drr_length, data, tx);
-	dmu_tx_commit(tx);
-	return (0);
-}
-
-/* ARGSUSED */
-static int
-restore_free(struct restorearg *ra, objset_t *os,
-    struct drr_free *drrf)
-{
-	dmu_tx_t *tx;
-	int err;
-
-	if (drrf->drr_length != -1ULL &&
-	    drrf->drr_offset + drrf->drr_length < drrf->drr_offset)
-		return (EINVAL);
-
-	if (dmu_object_info(os, drrf->drr_object, NULL) != 0)
-		return (EINVAL);
-
-	tx = dmu_tx_create(os);
-
-	dmu_tx_hold_free(tx, drrf->drr_object,
-	    drrf->drr_offset, drrf->drr_length);
-	err = dmu_tx_assign(tx, TXG_WAIT);
-	if (err) {
-		dmu_tx_abort(tx);
-		return (err);
-	}
-	err = dmu_free_range(os, drrf->drr_object,
-	    drrf->drr_offset, drrf->drr_length, tx);
-	dmu_tx_commit(tx);
-	return (err);
-}
-
-int
-dmu_recvbackup(char *tosnap, struct drr_begin *drrb, uint64_t *sizep,
-    boolean_t force, vnode_t *vp, uint64_t voffset)
-{
-	struct restorearg ra;
-	dmu_replay_record_t *drr;
-	char *cp;
-	objset_t *os = NULL;
-	zio_cksum_t pzc;
-
-	bzero(&ra, sizeof (ra));
-	ra.vp = vp;
-	ra.voff = voffset;
-	ra.bufsize = 1<<20;
-	ra.buf = kmem_alloc(ra.bufsize, KM_SLEEP);
-
-	if (drrb->drr_magic == DMU_BACKUP_MAGIC) {
-		ra.byteswap = FALSE;
-	} else if (drrb->drr_magic == BSWAP_64(DMU_BACKUP_MAGIC)) {
-		ra.byteswap = TRUE;
-	} else {
-		ra.err = EINVAL;
-		goto out;
-	}
-
-	/*
-	 * NB: this assumes that struct drr_begin will be the largest in
-	 * dmu_replay_record_t's drr_u, and thus we don't need to pad it
-	 * with zeros to make it the same length as we wrote out.
-	 */
-	((dmu_replay_record_t *)ra.buf)->drr_type = DRR_BEGIN;
-	((dmu_replay_record_t *)ra.buf)->drr_pad = 0;
-	((dmu_replay_record_t *)ra.buf)->drr_u.drr_begin = *drrb;
-	if (ra.byteswap) {
-		fletcher_4_incremental_byteswap(ra.buf,
-		    sizeof (dmu_replay_record_t), &ra.zc);
-	} else {
-		fletcher_4_incremental_native(ra.buf,
-		    sizeof (dmu_replay_record_t), &ra.zc);
-	}
-	(void) strcpy(drrb->drr_toname, tosnap); /* for the sync funcs */
-
-	if (ra.byteswap) {
-		drrb->drr_magic = BSWAP_64(drrb->drr_magic);
-		drrb->drr_version = BSWAP_64(drrb->drr_version);
-		drrb->drr_creation_time = BSWAP_64(drrb->drr_creation_time);
-		drrb->drr_type = BSWAP_32(drrb->drr_type);
-		drrb->drr_toguid = BSWAP_64(drrb->drr_toguid);
-		drrb->drr_fromguid = BSWAP_64(drrb->drr_fromguid);
-	}
-
-	ASSERT3U(drrb->drr_magic, ==, DMU_BACKUP_MAGIC);
-
-	if (drrb->drr_version != DMU_BACKUP_VERSION ||
-	    drrb->drr_type >= DMU_OST_NUMTYPES ||
-	    strchr(drrb->drr_toname, '@') == NULL) {
-		ra.err = EINVAL;
-		goto out;
-	}
-
-	/*
-	 * Process the begin in syncing context.
-	 */
-	if (drrb->drr_fromguid) {
-		/* incremental backup */
-		dsl_dataset_t *ds = NULL;
-
-		cp = strchr(tosnap, '@');
-		*cp = '\0';
-		ra.err = dsl_dataset_open(tosnap, DS_MODE_EXCLUSIVE, FTAG, &ds);
-		*cp = '@';
-		if (ra.err)
-			goto out;
-
-		/*
-		 * Only do the rollback if the most recent snapshot
-		 * matches the incremental source
-		 */
-		if (force) {
-			if (ds->ds_prev->ds_phys->ds_guid !=
-			    drrb->drr_fromguid) {
-				dsl_dataset_close(ds, DS_MODE_EXCLUSIVE, FTAG);
-				return (ENODEV);
-			}
-			(void) dsl_dataset_rollback(ds);
-		}
-		ra.err = dsl_sync_task_do(ds->ds_dir->dd_pool,
-		    replay_incremental_check, replay_incremental_sync,
-		    ds, drrb, 1);
-		dsl_dataset_close(ds, DS_MODE_EXCLUSIVE, FTAG);
-	} else {
-		/* full backup */
-		dsl_dir_t *dd = NULL;
-		const char *tail;
-
-		/* can't restore full backup into topmost fs, for now */
-		if (strrchr(drrb->drr_toname, '/') == NULL) {
-			ra.err = EINVAL;
-			goto out;
-		}
-
-		cp = strchr(tosnap, '@');
-		*cp = '\0';
-		ra.err = dsl_dir_open(tosnap, FTAG, &dd, &tail);
-		*cp = '@';
-		if (ra.err)
-			goto out;
-		if (tail == NULL) {
-			ra.err = EEXIST;
-			goto out;
-		}
-
-		ra.err = dsl_sync_task_do(dd->dd_pool, replay_full_check,
-		    replay_full_sync, dd, drrb, 5);
-		dsl_dir_close(dd, FTAG);
-	}
-	if (ra.err)
-		goto out;
-
-	/*
-	 * Open the objset we are modifying.
-	 */
-
-	cp = strchr(tosnap, '@');
-	*cp = '\0';
-	ra.err = dmu_objset_open(tosnap, DMU_OST_ANY,
-	    DS_MODE_PRIMARY | DS_MODE_INCONSISTENT, &os);
-	*cp = '@';
-	ASSERT3U(ra.err, ==, 0);
-
-	/*
-	 * Read records and process them.
-	 */
-	pzc = ra.zc;
-	while (ra.err == 0 &&
-	    NULL != (drr = restore_read(&ra, sizeof (*drr)))) {
-		if (issig(JUSTLOOKING) && issig(FORREAL)) {
-			ra.err = EINTR;
-			goto out;
-		}
-
-		if (ra.byteswap)
-			backup_byteswap(drr);
-
-		switch (drr->drr_type) {
-		case DRR_OBJECT:
-		{
-			/*
-			 * We need to make a copy of the record header,
-			 * because restore_{object,write} may need to
-			 * restore_read(), which will invalidate drr.
-			 */
-			struct drr_object drro = drr->drr_u.drr_object;
-			ra.err = restore_object(&ra, os, &drro);
-			break;
-		}
-		case DRR_FREEOBJECTS:
-		{
-			struct drr_freeobjects drrfo =
-			    drr->drr_u.drr_freeobjects;
-			ra.err = restore_freeobjects(&ra, os, &drrfo);
-			break;
-		}
-		case DRR_WRITE:
-		{
-			struct drr_write drrw = drr->drr_u.drr_write;
-			ra.err = restore_write(&ra, os, &drrw);
-			break;
-		}
-		case DRR_FREE:
-		{
-			struct drr_free drrf = drr->drr_u.drr_free;
-			ra.err = restore_free(&ra, os, &drrf);
-			break;
-		}
-		case DRR_END:
-		{
-			struct drr_end drre = drr->drr_u.drr_end;
-			/*
-			 * We compare against the *previous* checksum
-			 * value, because the stored checksum is of
-			 * everything before the DRR_END record.
-			 */
-			if (drre.drr_checksum.zc_word[0] != 0 &&
-			    ((drre.drr_checksum.zc_word[0] - pzc.zc_word[0]) |
-			    (drre.drr_checksum.zc_word[1] - pzc.zc_word[1]) |
-			    (drre.drr_checksum.zc_word[2] - pzc.zc_word[2]) |
-			    (drre.drr_checksum.zc_word[3] - pzc.zc_word[3]))) {
-				ra.err = ECKSUM;
-				goto out;
-			}
-
-			ra.err = dsl_sync_task_do(dmu_objset_ds(os)->
-			    ds_dir->dd_pool, replay_end_check, replay_end_sync,
-			    os, drrb, 3);
-			goto out;
-		}
-		default:
-			ra.err = EINVAL;
-			goto out;
-		}
-		pzc = ra.zc;
-	}
-
-out:
-	if (os)
-		dmu_objset_close(os);
-
-	/*
-	 * Make sure we don't rollback/destroy unless we actually
-	 * processed the begin properly.  'os' will only be set if this
-	 * is the case.
-	 */
-	if (ra.err && os && tosnap && strchr(tosnap, '@')) {
-		/*
-		 * rollback or destroy what we created, so we don't
-		 * leave it in the restoring state.
-		 */
-		dsl_dataset_t *ds;
-		int err;
-
-		cp = strchr(tosnap, '@');
-		*cp = '\0';
-		err = dsl_dataset_open(tosnap,
-		    DS_MODE_EXCLUSIVE | DS_MODE_INCONSISTENT,
-		    FTAG, &ds);
-		if (err == 0) {
-			txg_wait_synced(ds->ds_dir->dd_pool, 0);
-			if (drrb->drr_fromguid) {
-				/* incremental: rollback to most recent snap */
-				(void) dsl_dataset_rollback(ds);
-				dsl_dataset_close(ds, DS_MODE_EXCLUSIVE, FTAG);
-			} else {
-				/* full: destroy whole fs */
-				dsl_dataset_close(ds, DS_MODE_EXCLUSIVE, FTAG);
-				(void) dsl_dataset_destroy(tosnap);
-			}
-		}
-		*cp = '@';
-	}
-
-	kmem_free(ra.buf, ra.bufsize);
-	if (sizep)
-		*sizep = ra.voff;
-	return (ra.err);
-}
-
 typedef struct {
 	uint64_t	txg;
 	dmu_buf_impl_t	*db;

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/usr/src/uts/common/fs/zfs/dmu_send.c	Fri Sep 15 11:21:46 2006 -0700
@@ -0,0 +1,958 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License (the "License").
+ * You may not use this file except in compliance with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or http://www.opensolaris.org/os/licensing.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+/*
+ * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
+ * Use is subject to license terms.
+ */
+
+#pragma ident	"%Z%%M%	%I%	%E% SMI"
+
+#include <sys/dmu.h>
+#include <sys/dmu_impl.h>
+#include <sys/dmu_tx.h>
+#include <sys/dbuf.h>
+#include <sys/dnode.h>
+#include <sys/zfs_context.h>
+#include <sys/dmu_objset.h>
+#include <sys/dmu_traverse.h>
+#include <sys/dsl_dataset.h>
+#include <sys/dsl_dir.h>
+#include <sys/dsl_pool.h>
+#include <sys/dsl_synctask.h>
+#include <sys/zfs_ioctl.h>
+#include <sys/zap.h>
+#include <sys/zio_checksum.h>
+
+struct backuparg {
+	dmu_replay_record_t *drr;
+	vnode_t *vp;
+	objset_t *os;
+	zio_cksum_t zc;
+	int err;
+};
+
+static int
+dump_bytes(struct backuparg *ba, void *buf, int len)
+{
+	ssize_t resid; /* have to get resid to get detailed errno */
+	ASSERT3U(len % 8, ==, 0);
+
+	fletcher_4_incremental_native(buf, len, &ba->zc);
+	ba->err = vn_rdwr(UIO_WRITE, ba->vp,
+	    (caddr_t)buf, len,
+	    0, UIO_SYSSPACE, FAPPEND, RLIM64_INFINITY, CRED(), &resid);
+	return (ba->err);
+}
+
+static int
+dump_free(struct backuparg *ba, uint64_t object, uint64_t offset,
+    uint64_t length)
+{
+	/* write a FREE record */
+	bzero(ba->drr, sizeof (dmu_replay_record_t));
+	ba->drr->drr_type = DRR_FREE;
+	ba->drr->drr_u.drr_free.drr_object = object;
+	ba->drr->drr_u.drr_free.drr_offset = offset;
+	ba->drr->drr_u.drr_free.drr_length = length;
+
+	if (dump_bytes(ba, ba->drr, sizeof (dmu_replay_record_t)))
+		return (EINTR);
+	return (0);
+}
+
+static int
+dump_data(struct backuparg *ba, dmu_object_type_t type,
+    uint64_t object, uint64_t offset, int blksz, void *data)
+{
+	/* write a DATA record */
+	bzero(ba->drr, sizeof (dmu_replay_record_t));
+	ba->drr->drr_type = DRR_WRITE;
+	ba->drr->drr_u.drr_write.drr_object = object;
+	ba->drr->drr_u.drr_write.drr_type = type;
+	ba->drr->drr_u.drr_write.drr_offset = offset;
+	ba->drr->drr_u.drr_write.drr_length = blksz;
+
+	if (dump_bytes(ba, ba->drr, sizeof (dmu_replay_record_t)))
+		return (EINTR);
+	if (dump_bytes(ba, data, blksz))
+		return (EINTR);
+	return (0);
+}
+
+static int
+dump_freeobjects(struct backuparg *ba, uint64_t firstobj, uint64_t numobjs)
+{
+	/* write a FREEOBJECTS record */
+	bzero(ba->drr, sizeof (dmu_replay_record_t));
+	ba->drr->drr_type = DRR_FREEOBJECTS;
+	ba->drr->drr_u.drr_freeobjects.drr_firstobj = firstobj;
+	ba->drr->drr_u.drr_freeobjects.drr_numobjs = numobjs;
+
+	if (dump_bytes(ba, ba->drr, sizeof (dmu_replay_record_t)))
+		return (EINTR);
+	return (0);
+}
+
+static int
+dump_dnode(struct backuparg *ba, uint64_t object, dnode_phys_t *dnp)
+{
+	if (dnp == NULL || dnp->dn_type == DMU_OT_NONE)
+		return (dump_freeobjects(ba, object, 1));
+
+	/* write an OBJECT record */
+	bzero(ba->drr, sizeof (dmu_replay_record_t));
+	ba->drr->drr_type = DRR_OBJECT;
+	ba->drr->drr_u.drr_object.drr_object = object;
+	ba->drr->drr_u.drr_object.drr_type = dnp->dn_type;
+	ba->drr->drr_u.drr_object.drr_bonustype = dnp->dn_bonustype;
+	ba->drr->drr_u.drr_object.drr_blksz =
+	    dnp->dn_datablkszsec << SPA_MINBLOCKSHIFT;
+	ba->drr->drr_u.drr_object.drr_bonuslen = dnp->dn_bonuslen;
+	ba->drr->drr_u.drr_object.drr_checksum = dnp->dn_checksum;
+	ba->drr->drr_u.drr_object.drr_compress = dnp->dn_compress;
+
+	if (dump_bytes(ba, ba->drr, sizeof (dmu_replay_record_t)))
+		return (EINTR);
+
+	if (dump_bytes(ba, DN_BONUS(dnp), P2ROUNDUP(dnp->dn_bonuslen, 8)))
+		return (EINTR);
+
+	/* free anything past the end of the file */
+	if (dump_free(ba, object, (dnp->dn_maxblkid + 1) *
+	    (dnp->dn_datablkszsec << SPA_MINBLOCKSHIFT), -1ULL))
+		return (EINTR);
+	if (ba->err)
+		return (EINTR);
+	return (0);
+}
+
+#define	BP_SPAN(dnp, level) \
+	(((uint64_t)dnp->dn_datablkszsec) << (SPA_MINBLOCKSHIFT + \
+	(level) * (dnp->dn_indblkshift - SPA_BLKPTRSHIFT)))
+
+static int
+backup_cb(traverse_blk_cache_t *bc, spa_t *spa, void *arg)
+{
+	struct backuparg *ba = arg;
+	uint64_t object = bc->bc_bookmark.zb_object;
+	int level = bc->bc_bookmark.zb_level;
+	uint64_t blkid = bc->bc_bookmark.zb_blkid;
+	blkptr_t *bp = bc->bc_blkptr.blk_birth ? &bc->bc_blkptr : NULL;
+	dmu_object_type_t type = bp ? BP_GET_TYPE(bp) : DMU_OT_NONE;
+	void *data = bc->bc_data;
+	int err = 0;
+
+	if (issig(JUSTLOOKING) && issig(FORREAL))
+		return (EINTR);
+
+	ASSERT(data || bp == NULL);
+
+	if (bp == NULL && object == 0) {
+		uint64_t span = BP_SPAN(bc->bc_dnode, level);
+		uint64_t dnobj = (blkid * span) >> DNODE_SHIFT;
+		err = dump_freeobjects(ba, dnobj, span >> DNODE_SHIFT);
+	} else if (bp == NULL) {
+		uint64_t span = BP_SPAN(bc->bc_dnode, level);
+		err = dump_free(ba, object, blkid * span, span);
+	} else if (data && level == 0 && type == DMU_OT_DNODE) {
+		dnode_phys_t *blk = data;
+		int i;
+		int blksz = BP_GET_LSIZE(bp);
+
+		for (i = 0; i < blksz >> DNODE_SHIFT; i++) {
+			uint64_t dnobj =
+			    (blkid << (DNODE_BLOCK_SHIFT - DNODE_SHIFT)) + i;
+			err = dump_dnode(ba, dnobj, blk+i);
+			if (err)
+				break;
+		}
+	} else if (level == 0 &&
+	    type != DMU_OT_DNODE && type != DMU_OT_OBJSET) {
+		int blksz = BP_GET_LSIZE(bp);
+		if (data == NULL) {
+			uint32_t aflags = ARC_WAIT;
+			arc_buf_t *abuf;
+			zbookmark_t zb;
+
+			zb.zb_objset = ba->os->os->os_dsl_dataset->ds_object;
+			zb.zb_object = object;
+			zb.zb_level = level;
+			zb.zb_blkid = blkid;
+			(void) arc_read(NULL, spa, bp,
+			    dmu_ot[type].ot_byteswap, arc_getbuf_func, &abuf,
+			    ZIO_PRIORITY_ASYNC_READ, ZIO_FLAG_MUSTSUCCEED,
+			    &aflags, &zb);
+
+			if (abuf) {
+				err = dump_data(ba, type, object, blkid * blksz,
+				    blksz, abuf->b_data);
+				(void) arc_buf_remove_ref(abuf, &abuf);
+			}
+		} else {
+			err = dump_data(ba, type, object, blkid * blksz,
+			    blksz, data);
+		}
+	}
+
+	ASSERT(err == 0 || err == EINTR);
+	return (err);
+}
+
+int
+dmu_sendbackup(objset_t *tosnap, objset_t *fromsnap, vnode_t *vp)
+{
+	dsl_dataset_t *ds = tosnap->os->os_dsl_dataset;
+	dsl_dataset_t *fromds = fromsnap ? fromsnap->os->os_dsl_dataset : NULL;
+	dmu_replay_record_t *drr;
+	struct backuparg ba;
+	int err;
+
+	/* tosnap must be a snapshot */
+	if (ds->ds_phys->ds_next_snap_obj == 0)
+		return (EINVAL);
+
+	/* fromsnap must be an earlier snapshot from the same fs as tosnap */
+	if (fromds && (ds->ds_dir != fromds->ds_dir ||
+	    fromds->ds_phys->ds_creation_txg >=
+	    ds->ds_phys->ds_creation_txg))
+		return (EXDEV);
+
+	drr = kmem_zalloc(sizeof (dmu_replay_record_t), KM_SLEEP);
+	drr->drr_type = DRR_BEGIN;
+	drr->drr_u.drr_begin.drr_magic = DMU_BACKUP_MAGIC;
+	drr->drr_u.drr_begin.drr_version = DMU_BACKUP_VERSION;
+	drr->drr_u.drr_begin.drr_creation_time =
+	    ds->ds_phys->ds_creation_time;
+	drr->drr_u.drr_begin.drr_type = tosnap->os->os_phys->os_type;
+	drr->drr_u.drr_begin.drr_toguid = ds->ds_phys->ds_guid;
+	if (fromds)
+		drr->drr_u.drr_begin.drr_fromguid = fromds->ds_phys->ds_guid;
+	dsl_dataset_name(ds, drr->drr_u.drr_begin.drr_toname);
+
+	ba.drr = drr;
+	ba.vp = vp;
+	ba.os = tosnap;
+	ZIO_SET_CHECKSUM(&ba.zc, 0, 0, 0, 0);
+
+	if (dump_bytes(&ba, drr, sizeof (dmu_replay_record_t))) {
+		kmem_free(drr, sizeof (dmu_replay_record_t));
+		return (ba.err);
+	}
+
+	err = traverse_dsl_dataset(ds,
+	    fromds ? fromds->ds_phys->ds_creation_txg : 0,
+	    ADVANCE_PRE | ADVANCE_HOLES | ADVANCE_DATA | ADVANCE_NOLOCK,
+	    backup_cb, &ba);
+
+	if (err) {
+		if (err == EINTR && ba.err)
+			err = ba.err;
+		return (err);
+	}
+
+	bzero(drr, sizeof (dmu_replay_record_t));
+	drr->drr_type = DRR_END;
+	drr->drr_u.drr_end.drr_checksum = ba.zc;
+
+	if (dump_bytes(&ba, drr, sizeof (dmu_replay_record_t)))
+		return (ba.err);
+
+	kmem_free(drr, sizeof (dmu_replay_record_t));
+
+	return (0);
+}
+
+struct restorearg {
+	int err;
+	int byteswap;
+	vnode_t *vp;
+	char *buf;
+	uint64_t voff;
+	int buflen; /* number of valid bytes in buf */
+	int bufoff; /* next offset to read */
+	int bufsize; /* amount of memory allocated for buf */
+	zio_cksum_t zc;
+};
+
+/* ARGSUSED */
+static int
+replay_incremental_check(void *arg1, void *arg2, dmu_tx_t *tx)
+{
+	dsl_dataset_t *ds = arg1;
+	struct drr_begin *drrb = arg2;
+	const char *snapname;
+	int err;
+	uint64_t val;
+
+	/* must already be a snapshot of this fs */
+	if (ds->ds_phys->ds_prev_snap_obj == 0)
+		return (ENODEV);
+
+	/* most recent snapshot must match fromguid */
+	if (ds->ds_prev->ds_phys->ds_guid != drrb->drr_fromguid)
+		return (ENODEV);
+	/* must not have any changes since most recent snapshot */
+	if (ds->ds_phys->ds_bp.blk_birth >
+	    ds->ds_prev->ds_phys->ds_creation_txg)
+		return (ETXTBSY);
+
+	/* new snapshot name must not exist */
+	snapname = strrchr(drrb->drr_toname, '@');
+	if (snapname == NULL)
+		return (EEXIST);
+
+	snapname++;
+	err = zap_lookup(ds->ds_dir->dd_pool->dp_meta_objset,
+	    ds->ds_phys->ds_snapnames_zapobj, snapname, 8, 1, &val);
+	if (err == 0)
+		return (EEXIST);
+	if (err != ENOENT)
+		return (err);
+
+	return (0);
+}
+
+/* ARGSUSED */
+static void
+replay_incremental_sync(void *arg1, void *arg2, dmu_tx_t *tx)
+{
+	dsl_dataset_t *ds = arg1;
+	dmu_buf_will_dirty(ds->ds_dbuf, tx);
+	ds->ds_phys->ds_flags |= DS_FLAG_INCONSISTENT;
+}
+
+/* ARGSUSED */
+static int
+replay_full_check(void *arg1, void *arg2, dmu_tx_t *tx)
+{
+	dsl_dir_t *dd = arg1;
+	struct drr_begin *drrb = arg2;
+	objset_t *mos = dd->dd_pool->dp_meta_objset;
+	char *cp;
+	uint64_t val;
+	int err;
+
+	cp = strchr(drrb->drr_toname, '@');
+	*cp = '\0';
+	err = zap_lookup(mos, dd->dd_phys->dd_child_dir_zapobj,
+	    strrchr(drrb->drr_toname, '/') + 1,
+	    sizeof (uint64_t), 1, &val);
+	*cp = '@';
+
+	if (err != ENOENT)
+		return (err ? err : EEXIST);
+
+	return (0);
+}
+
+static void
+replay_full_sync(void *arg1, void *arg2, dmu_tx_t *tx)
+{
+	dsl_dir_t *dd = arg1;
+	struct drr_begin *drrb = arg2;
+	char *cp;
+	dsl_dataset_t *ds;
+	uint64_t dsobj;
+
+	cp = strchr(drrb->drr_toname, '@');
+	*cp = '\0';
+	dsobj = dsl_dataset_create_sync(dd, strrchr(drrb->drr_toname, '/') + 1,
+	    NULL, tx);
+	*cp = '@';
+
+	VERIFY(0 == dsl_dataset_open_obj(dd->dd_pool, dsobj, NULL,
+	    DS_MODE_EXCLUSIVE, FTAG, &ds));
+
+	(void) dmu_objset_create_impl(dsl_dataset_get_spa(ds),
+	    ds, drrb->drr_type, tx);
+
+	dmu_buf_will_dirty(ds->ds_dbuf, tx);
+	ds->ds_phys->ds_flags |= DS_FLAG_INCONSISTENT;
+
+	dsl_dataset_close(ds, DS_MODE_EXCLUSIVE, FTAG);
+}
+
+static int
+replay_end_check(void *arg1, void *arg2, dmu_tx_t *tx)
+{
+	objset_t *os = arg1;
+	struct drr_begin *drrb = arg2;
+	char *snapname;
+
+	/* XXX verify that drr_toname is in dd */
+
+	snapname = strchr(drrb->drr_toname, '@');
+	if (snapname == NULL)
+		return (EINVAL);
+	snapname++;
+
+	return (dsl_dataset_snapshot_check(os, snapname, tx));
+}
+
+static void
+replay_end_sync(void *arg1, void *arg2, dmu_tx_t *tx)
+{
+	objset_t *os = arg1;
+	struct drr_begin *drrb = arg2;
+	char *snapname;
+	dsl_dataset_t *ds, *hds;
+
+	snapname = strchr(drrb->drr_toname, '@') + 1;
+
+	dsl_dataset_snapshot_sync(os, snapname, tx);
+
+	/* set snapshot's creation time and guid */
+	hds = os->os->os_dsl_dataset;
+	VERIFY(0 == dsl_dataset_open_obj(hds->ds_dir->dd_pool,
+	    hds->ds_phys->ds_prev_snap_obj, NULL,
+	    DS_MODE_PRIMARY | DS_MODE_READONLY | DS_MODE_INCONSISTENT,
+	    FTAG, &ds));
+
+	dmu_buf_will_dirty(ds->ds_dbuf, tx);
+	ds->ds_phys->ds_creation_time = drrb->drr_creation_time;
+	ds->ds_phys->ds_guid = drrb->drr_toguid;
+	ds->ds_phys->ds_flags &= ~DS_FLAG_INCONSISTENT;
+
+	dsl_dataset_close(ds, DS_MODE_PRIMARY, FTAG);
+
+	dmu_buf_will_dirty(hds->ds_dbuf, tx);
+	hds->ds_phys->ds_flags &= ~DS_FLAG_INCONSISTENT;
+}
+
+static void *
+restore_read(struct restorearg *ra, int len)
+{
+	void *rv;
+
+	/* some things will require 8-byte alignment, so everything must */
+	ASSERT3U(len % 8, ==, 0);
+
+	while (ra->buflen - ra->bufoff < len) {
+		ssize_t resid;
+		int leftover = ra->buflen - ra->bufoff;
+
+		(void) memmove(ra->buf, ra->buf + ra->bufoff, leftover);
+		ra->err = vn_rdwr(UIO_READ, ra->vp,
+		    (caddr_t)ra->buf + leftover, ra->bufsize - leftover,
+		    ra->voff, UIO_SYSSPACE, FAPPEND,
+		    RLIM64_INFINITY, CRED(), &resid);
+
+		ra->voff += ra->bufsize - leftover - resid;
+		ra->buflen = ra->bufsize - resid;
+		ra->bufoff = 0;
+		if (resid == ra->bufsize - leftover)
+			ra->err = EINVAL;
+		if (ra->err)
+			return (NULL);
+		/* Could compute checksum here? */
+	}
+
+	ASSERT3U(ra->bufoff % 8, ==, 0);
+	ASSERT3U(ra->buflen - ra->bufoff, >=, len);
+	rv = ra->buf + ra->bufoff;
+	ra->bufoff += len;
+	if (ra->byteswap)
+		fletcher_4_incremental_byteswap(rv, len, &ra->zc);
+	else
+		fletcher_4_incremental_native(rv, len, &ra->zc);
+	return (rv);
+}
+
+static void
+backup_byteswap(dmu_replay_record_t *drr)
+{
+#define	DO64(X) (drr->drr_u.X = BSWAP_64(drr->drr_u.X))
+#define	DO32(X) (drr->drr_u.X = BSWAP_32(drr->drr_u.X))
+	drr->drr_type = BSWAP_32(drr->drr_type);
+	switch (drr->drr_type) {
+	case DRR_BEGIN:
+		DO64(drr_begin.drr_magic);
+		DO64(drr_begin.drr_version);
+		DO64(drr_begin.drr_creation_time);
+		DO32(drr_begin.drr_type);
+		DO64(drr_begin.drr_toguid);
+		DO64(drr_begin.drr_fromguid);
+		break;
+	case DRR_OBJECT:
+		DO64(drr_object.drr_object);
+		/* DO64(drr_object.drr_allocation_txg); */
+		DO32(drr_object.drr_type);
+		DO32(drr_object.drr_bonustype);
+		DO32(drr_object.drr_blksz);
+		DO32(drr_object.drr_bonuslen);
+		break;
+	case DRR_FREEOBJECTS:
+		DO64(drr_freeobjects.drr_firstobj);
+		DO64(drr_freeobjects.drr_numobjs);
+		break;
+	case DRR_WRITE:
+		DO64(drr_write.drr_object);
+		DO32(drr_write.drr_type);
+		DO64(drr_write.drr_offset);
+		DO64(drr_write.drr_length);
+		break;
+	case DRR_FREE:
+		DO64(drr_free.drr_object);
+		DO64(drr_free.drr_offset);
+		DO64(drr_free.drr_length);
+		break;
+	case DRR_END:
+		DO64(drr_end.drr_checksum.zc_word[0]);
+		DO64(drr_end.drr_checksum.zc_word[1]);
+		DO64(drr_end.drr_checksum.zc_word[2]);
+		DO64(drr_end.drr_checksum.zc_word[3]);
+		break;
+	}
+#undef DO64
+#undef DO32
+}
+
+static int
+restore_object(struct restorearg *ra, objset_t *os, struct drr_object *drro)
+{
+	int err;
+	dmu_tx_t *tx;
+
+	err = dmu_object_info(os, drro->drr_object, NULL);
+
+	if (err != 0 && err != ENOENT)
+		return (EINVAL);
+
+	if (drro->drr_type == DMU_OT_NONE ||
+	    drro->drr_type >= DMU_OT_NUMTYPES ||
+	    drro->drr_bonustype >= DMU_OT_NUMTYPES ||
+	    drro->drr_checksum >= ZIO_CHECKSUM_FUNCTIONS ||
+	    drro->drr_compress >= ZIO_COMPRESS_FUNCTIONS ||
+	    P2PHASE(drro->drr_blksz, SPA_MINBLOCKSIZE) ||
+	    drro->drr_blksz < SPA_MINBLOCKSIZE ||
+	    drro->drr_blksz > SPA_MAXBLOCKSIZE ||
+	    drro->drr_bonuslen > DN_MAX_BONUSLEN) {
+		return (EINVAL);
+	}
+
+	tx = dmu_tx_create(os);
+
+	if (err == ENOENT) {
+		/* currently free, want to be allocated */
+		dmu_tx_hold_bonus(tx, DMU_NEW_OBJECT);
+		dmu_tx_hold_write(tx, DMU_NEW_OBJECT, 0, 1);
+		err = dmu_tx_assign(tx, TXG_WAIT);
+		if (err) {
+			dmu_tx_abort(tx);
+			return (err);
+		}
+		err = dmu_object_claim(os, drro->drr_object,
+		    drro->drr_type, drro->drr_blksz,
+		    drro->drr_bonustype, drro->drr_bonuslen, tx);
+	} else {
+		/* currently allocated, want to be allocated */
+		dmu_tx_hold_bonus(tx, drro->drr_object);
+		/*
+		 * We may change blocksize, so need to
+		 * hold_write
+		 */
+		dmu_tx_hold_write(tx, drro->drr_object, 0, 1);
+		err = dmu_tx_assign(tx, TXG_WAIT);
+		if (err) {
+			dmu_tx_abort(tx);
+			return (err);
+		}
+
+		err = dmu_object_reclaim(os, drro->drr_object,
+		    drro->drr_type, drro->drr_blksz,
+		    drro->drr_bonustype, drro->drr_bonuslen, tx);
+	}
+	if (err) {
+		dmu_tx_commit(tx);
+		return (EINVAL);
+	}
+
+	dmu_object_set_checksum(os, drro->drr_object, drro->drr_checksum, tx);
+	dmu_object_set_compress(os, drro->drr_object, drro->drr_compress, tx);
+
+	if (drro->drr_bonuslen) {
+		dmu_buf_t *db;
+		void *data;
+		VERIFY(0 == dmu_bonus_hold(os, drro->drr_object, FTAG, &db));
+		dmu_buf_will_dirty(db, tx);
+
+		ASSERT3U(db->db_size, ==, drro->drr_bonuslen);
+		data = restore_read(ra, P2ROUNDUP(db->db_size, 8));
+		if (data == NULL) {
+			dmu_tx_commit(tx);
+			return (ra->err);
+		}
+		bcopy(data, db->db_data, db->db_size);
+		if (ra->byteswap) {
+			dmu_ot[drro->drr_bonustype].ot_byteswap(db->db_data,
+			    drro->drr_bonuslen);
+		}
+		dmu_buf_rele(db, FTAG);
+	}
+	dmu_tx_commit(tx);
+	return (0);
+}
+
+/* ARGSUSED */
+static int
+restore_freeobjects(struct restorearg *ra, objset_t *os,
+    struct drr_freeobjects *drrfo)
+{
+	uint64_t obj;
+
+	if (drrfo->drr_firstobj + drrfo->drr_numobjs < drrfo->drr_firstobj)
+		return (EINVAL);
+
+	for (obj = drrfo->drr_firstobj;
+	    obj < drrfo->drr_firstobj + drrfo->drr_numobjs; obj++) {
+		dmu_tx_t *tx;
+		int err;
+
+		if (dmu_object_info(os, obj, NULL) != 0)
+			continue;
+
+		tx = dmu_tx_create(os);
+		dmu_tx_hold_bonus(tx, obj);
+		err = dmu_tx_assign(tx, TXG_WAIT);
+		if (err) {
+			dmu_tx_abort(tx);
+			return (err);
+		}
+		err = dmu_object_free(os, obj, tx);
+		dmu_tx_commit(tx);
+		if (err && err != ENOENT)
+			return (EINVAL);
+	}
+	return (0);
+}
+
+static int
+restore_write(struct restorearg *ra, objset_t *os,
+    struct drr_write *drrw)
+{
+	dmu_tx_t *tx;
+	void *data;
+	int err;
+
+	if (drrw->drr_offset + drrw->drr_length < drrw->drr_offset ||
+	    drrw->drr_type >= DMU_OT_NUMTYPES)
+		return (EINVAL);
+
+	data = restore_read(ra, drrw->drr_length);
+	if (data == NULL)
+		return (ra->err);
+
+	if (dmu_object_info(os, drrw->drr_object, NULL) != 0)
+		return (EINVAL);
+
+	tx = dmu_tx_create(os);
+
+	dmu_tx_hold_write(tx, drrw->drr_object,
+	    drrw->drr_offset, drrw->drr_length);
+	err = dmu_tx_assign(tx, TXG_WAIT);
+	if (err) {
+		dmu_tx_abort(tx);
+		return (err);
+	}
+	if (ra->byteswap)
+		dmu_ot[drrw->drr_type].ot_byteswap(data, drrw->drr_length);
+	dmu_write(os, drrw->drr_object,
+	    drrw->drr_offset, drrw->drr_length, data, tx);
+	dmu_tx_commit(tx);
+	return (0);
+}
+
+/* ARGSUSED */
+static int
+restore_free(struct restorearg *ra, objset_t *os,
+    struct drr_free *drrf)
+{
+	dmu_tx_t *tx;
+	int err;
+
+	if (drrf->drr_length != -1ULL &&
+	    drrf->drr_offset + drrf->drr_length < drrf->drr_offset)
+		return (EINVAL);
+
+	if (dmu_object_info(os, drrf->drr_object, NULL) != 0)
+		return (EINVAL);
+
+	tx = dmu_tx_create(os);
+
+	dmu_tx_hold_free(tx, drrf->drr_object,
+	    drrf->drr_offset, drrf->drr_length);
+	err = dmu_tx_assign(tx, TXG_WAIT);
+	if (err) {
+		dmu_tx_abort(tx);
+		return (err);
+	}
+	err = dmu_free_range(os, drrf->drr_object,
+	    drrf->drr_offset, drrf->drr_length, tx);
+	dmu_tx_commit(tx);
+	return (err);
+}
+
+int
+dmu_recvbackup(char *tosnap, struct drr_begin *drrb, uint64_t *sizep,
+    boolean_t force, vnode_t *vp, uint64_t voffset)
+{
+	struct restorearg ra;
+	dmu_replay_record_t *drr;
+	char *cp;
+	objset_t *os = NULL;
+	zio_cksum_t pzc;
+
+	bzero(&ra, sizeof (ra));
+	ra.vp = vp;
+	ra.voff = voffset;
+	ra.bufsize = 1<<20;
+	ra.buf = kmem_alloc(ra.bufsize, KM_SLEEP);
+
+	if (drrb->drr_magic == DMU_BACKUP_MAGIC) {
+		ra.byteswap = FALSE;
+	} else if (drrb->drr_magic == BSWAP_64(DMU_BACKUP_MAGIC)) {
+		ra.byteswap = TRUE;
+	} else {
+		ra.err = EINVAL;
+		goto out;
+	}
+
+	/*
+	 * NB: this assumes that struct drr_begin will be the largest in
+	 * dmu_replay_record_t's drr_u, and thus we don't need to pad it
+	 * with zeros to make it the same length as we wrote out.
+	 */
+	((dmu_replay_record_t *)ra.buf)->drr_type = DRR_BEGIN;
+	((dmu_replay_record_t *)ra.buf)->drr_pad = 0;
+	((dmu_replay_record_t *)ra.buf)->drr_u.drr_begin = *drrb;
+	if (ra.byteswap) {
+		fletcher_4_incremental_byteswap(ra.buf,
+		    sizeof (dmu_replay_record_t), &ra.zc);
+	} else {
+		fletcher_4_incremental_native(ra.buf,
+		    sizeof (dmu_replay_record_t), &ra.zc);
+	}
+	(void) strcpy(drrb->drr_toname, tosnap); /* for the sync funcs */
+
+	if (ra.byteswap) {
+		drrb->drr_magic = BSWAP_64(drrb->drr_magic);
+		drrb->drr_version = BSWAP_64(drrb->drr_version);
+		drrb->drr_creation_time = BSWAP_64(drrb->drr_creation_time);
+		drrb->drr_type = BSWAP_32(drrb->drr_type);
+		drrb->drr_toguid = BSWAP_64(drrb->drr_toguid);
+		drrb->drr_fromguid = BSWAP_64(drrb->drr_fromguid);
+	}
+
+	ASSERT3U(drrb->drr_magic, ==, DMU_BACKUP_MAGIC);
+
+	if (drrb->drr_version != DMU_BACKUP_VERSION ||
+	    drrb->drr_type >= DMU_OST_NUMTYPES ||
+	    strchr(drrb->drr_toname, '@') == NULL) {
+		ra.err = EINVAL;
+		goto out;
+	}
+
+	/*
+	 * Process the begin in syncing context.
+	 */
+	if (drrb->drr_fromguid) {
+		/* incremental backup */
+		dsl_dataset_t *ds = NULL;
+
+		cp = strchr(tosnap, '@');
+		*cp = '\0';
+		ra.err = dsl_dataset_open(tosnap, DS_MODE_EXCLUSIVE, FTAG, &ds);
+		*cp = '@';
+		if (ra.err)
+			goto out;
+
+		/*
+		 * Only do the rollback if the most recent snapshot
+		 * matches the incremental source
+		 */
+		if (force) {
+			if (ds->ds_prev->ds_phys->ds_guid !=
+			    drrb->drr_fromguid) {
+				dsl_dataset_close(ds, DS_MODE_EXCLUSIVE, FTAG);
+				return (ENODEV);
+			}
+			(void) dsl_dataset_rollback(ds);
+		}
+		ra.err = dsl_sync_task_do(ds->ds_dir->dd_pool,
+		    replay_incremental_check, replay_incremental_sync,
+		    ds, drrb, 1);
+		dsl_dataset_close(ds, DS_MODE_EXCLUSIVE, FTAG);
+	} else {
+		/* full backup */
+		dsl_dir_t *dd = NULL;
+		const char *tail;
+
+		/* can't restore full backup into topmost fs, for now */
+		if (strrchr(drrb->drr_toname, '/') == NULL) {
+			ra.err = EINVAL;
+			goto out;
+		}
+
+		cp = strchr(tosnap, '@');
+		*cp = '\0';
+		ra.err = dsl_dir_open(tosnap, FTAG, &dd, &tail);
+		*cp = '@';
+		if (ra.err)
+			goto out;
+		if (tail == NULL) {
+			ra.err = EEXIST;
+			goto out;
+		}
+
+		ra.err = dsl_sync_task_do(dd->dd_pool, replay_full_check,
+		    replay_full_sync, dd, drrb, 5);
+		dsl_dir_close(dd, FTAG);
+	}
+	if (ra.err)
+		goto out;
+
+	/*
+	 * Open the objset we are modifying.
+	 */
+
+	cp = strchr(tosnap, '@');
+	*cp = '\0';
+	ra.err = dmu_objset_open(tosnap, DMU_OST_ANY,
+	    DS_MODE_PRIMARY | DS_MODE_INCONSISTENT, &os);
+	*cp = '@';
+	ASSERT3U(ra.err, ==, 0);
+
+	/*
+	 * Read records and process them.
+	 */
+	pzc = ra.zc;
+	while (ra.err == 0 &&
+	    NULL != (drr = restore_read(&ra, sizeof (*drr)))) {
+		if (issig(JUSTLOOKING) && issig(FORREAL)) {
+			ra.err = EINTR;
+			goto out;
+		}
+
+		if (ra.byteswap)
+			backup_byteswap(drr);
+
+		switch (drr->drr_type) {
+		case DRR_OBJECT:
+		{
+			/*
+			 * We need to make a copy of the record header,
+			 * because restore_{object,write} may need to
+			 * restore_read(), which will invalidate drr.
+			 */
+			struct drr_object drro = drr->drr_u.drr_object;
+			ra.err = restore_object(&ra, os, &drro);
+			break;
+		}
+		case DRR_FREEOBJECTS:
+		{
+			struct drr_freeobjects drrfo =
+			    drr->drr_u.drr_freeobjects;
+			ra.err = restore_freeobjects(&ra, os, &drrfo);
+			break;
+		}
+		case DRR_WRITE:
+		{
+			struct drr_write drrw = drr->drr_u.drr_write;
+			ra.err = restore_write(&ra, os, &drrw);
+			break;
+		}
+		case DRR_FREE:
+		{
+			struct drr_free drrf = drr->drr_u.drr_free;
+			ra.err = restore_free(&ra, os, &drrf);
+			break;
+		}
+		case DRR_END:
+		{
+			struct drr_end drre = drr->drr_u.drr_end;
+			/*
+			 * We compare against the *previous* checksum
+			 * value, because the stored checksum is of
+			 * everything before the DRR_END record.
+			 */
+			if (drre.drr_checksum.zc_word[0] != 0 &&
+			    ((drre.drr_checksum.zc_word[0] - pzc.zc_word[0]) |
+			    (drre.drr_checksum.zc_word[1] - pzc.zc_word[1]) |
+			    (drre.drr_checksum.zc_word[2] - pzc.zc_word[2]) |
+			    (drre.drr_checksum.zc_word[3] - pzc.zc_word[3]))) {
+				ra.err = ECKSUM;
+				goto out;
+			}
+
+			ra.err = dsl_sync_task_do(dmu_objset_ds(os)->
+			    ds_dir->dd_pool, replay_end_check, replay_end_sync,
+			    os, drrb, 3);
+			goto out;
+		}
+		default:
+			ra.err = EINVAL;
+			goto out;
+		}
+		pzc = ra.zc;
+	}
+
+out:
+	if (os)
+		dmu_objset_close(os);
+
+	/*
+	 * Make sure we don't rollback/destroy unless we actually
+	 * processed the begin properly.  'os' will only be set if this
+	 * is the case.
+	 */
+	if (ra.err && os && tosnap && strchr(tosnap, '@')) {
+		/*
+		 * rollback or destroy what we created, so we don't
+		 * leave it in the restoring state.
+		 */
+		dsl_dataset_t *ds;
+		int err;
+
+		cp = strchr(tosnap, '@');
+		*cp = '\0';
+		err = dsl_dataset_open(tosnap,
+		    DS_MODE_EXCLUSIVE | DS_MODE_INCONSISTENT,
+		    FTAG, &ds);
+		if (err == 0) {
+			txg_wait_synced(ds->ds_dir->dd_pool, 0);
+			if (drrb->drr_fromguid) {
+				/* incremental: rollback to most recent snap */
+				(void) dsl_dataset_rollback(ds);
+				dsl_dataset_close(ds, DS_MODE_EXCLUSIVE, FTAG);
+			} else {
+				/* full: destroy whole fs */
+				dsl_dataset_close(ds, DS_MODE_EXCLUSIVE, FTAG);
+				(void) dsl_dataset_destroy(tosnap);
+			}
+		}
+		*cp = '@';
+	}
+
+	kmem_free(ra.buf, ra.bufsize);
+	if (sizep)
+		*sizep = ra.voff;
+	return (ra.err);
+}