Move the world out of /zfs/ and seperate out module build tree

1 files changed, 1181 insertions, 0 deletions

diff --git a/module/zfs/dmu_send.c b/module/zfs/dmu_send.c
new file mode 100644
index 000000000..857b9a343
--- /dev/null
+++ b/module/zfs/dmu_send.c
@@ -0,0 +1,1181 @@
+/*
+ * 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 2008 Sun Microsystems, Inc.  All rights reserved.
+ * Use is subject to license terms.
+ */
+
+#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>
+
+static char *dmu_recv_tag = "dmu_recv_tag";
+
+struct backuparg {
+	dmu_replay_record_t *drr;
+	vnode_t *vp;
+	offset_t *off;
+	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);
+	*ba->off += len;
+	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(spa_t *spa, blkptr_t *bp, const zbookmark_t *zb,
+    const dnode_phys_t *dnp, void *arg)
+{
+	struct backuparg *ba = arg;
+	dmu_object_type_t type = bp ? BP_GET_TYPE(bp) : DMU_OT_NONE;
+	int err = 0;
+
+	if (issig(JUSTLOOKING) && issig(FORREAL))
+		return (EINTR);
+
+	if (bp == NULL && zb->zb_object == 0) {
+		uint64_t span = BP_SPAN(dnp, zb->zb_level);
+		uint64_t dnobj = (zb->zb_blkid * span) >> DNODE_SHIFT;
+		err = dump_freeobjects(ba, dnobj, span >> DNODE_SHIFT);
+	} else if (bp == NULL) {
+		uint64_t span = BP_SPAN(dnp, zb->zb_level);
+		err = dump_free(ba, zb->zb_object, zb->zb_blkid * span, span);
+	} else if (zb->zb_level > 0 || type == DMU_OT_OBJSET) {
+		return (0);
+	} else if (type == DMU_OT_DNODE) {
+		dnode_phys_t *blk;
+		int i;
+		int blksz = BP_GET_LSIZE(bp);
+		uint32_t aflags = ARC_WAIT;
+		arc_buf_t *abuf;
+
+		if (arc_read_nolock(NULL, spa, bp,
+		    arc_getbuf_func, &abuf, ZIO_PRIORITY_ASYNC_READ,
+		    ZIO_FLAG_CANFAIL, &aflags, zb) != 0)
+			return (EIO);
+
+		blk = abuf->b_data;
+		for (i = 0; i < blksz >> DNODE_SHIFT; i++) {
+			uint64_t dnobj = (zb->zb_blkid <<
+			    (DNODE_BLOCK_SHIFT - DNODE_SHIFT)) + i;
+			err = dump_dnode(ba, dnobj, blk+i);
+			if (err)
+				break;
+		}
+		(void) arc_buf_remove_ref(abuf, &abuf);
+	} else { /* it's a level-0 block of a regular object */
+		uint32_t aflags = ARC_WAIT;
+		arc_buf_t *abuf;
+		int blksz = BP_GET_LSIZE(bp);
+
+		if (arc_read_nolock(NULL, spa, bp,
+		    arc_getbuf_func, &abuf, ZIO_PRIORITY_ASYNC_READ,
+		    ZIO_FLAG_CANFAIL, &aflags, zb) != 0)
+			return (EIO);
+
+		err = dump_data(ba, type, zb->zb_object, zb->zb_blkid * blksz,
+		    blksz, abuf->b_data);
+		(void) arc_buf_remove_ref(abuf, &abuf);
+	}
+
+	ASSERT(err == 0 || err == EINTR);
+	return (err);
+}
+
+int
+dmu_sendbackup(objset_t *tosnap, objset_t *fromsnap, boolean_t fromorigin,
+    vnode_t *vp, offset_t *off)
+{
+	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;
+	uint64_t fromtxg = 0;
+
+	/* 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);
+
+	if (fromorigin) {
+		dsl_pool_t *dp = ds->ds_dir->dd_pool;
+
+		if (fromsnap)
+			return (EINVAL);
+
+		if (dsl_dir_is_clone(ds->ds_dir)) {
+			rw_enter(&dp->dp_config_rwlock, RW_READER);
+			err = dsl_dataset_hold_obj(dp,
+			    ds->ds_dir->dd_phys->dd_origin_obj, FTAG, &fromds);
+			rw_exit(&dp->dp_config_rwlock);
+			if (err)
+				return (err);
+		} else {
+			fromorigin = B_FALSE;
+		}
+	}
+
+
+	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_STREAM_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;
+	if (fromorigin)
+		drr->drr_u.drr_begin.drr_flags |= DRR_FLAG_CLONE;
+	drr->drr_u.drr_begin.drr_toguid = ds->ds_phys->ds_guid;
+	if (ds->ds_phys->ds_flags & DS_FLAG_CI_DATASET)
+		drr->drr_u.drr_begin.drr_flags |= DRR_FLAG_CI_DATA;
+
+	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);
+
+	if (fromds)
+		fromtxg = fromds->ds_phys->ds_creation_txg;
+	if (fromorigin)
+		dsl_dataset_rele(fromds, FTAG);
+
+	ba.drr = drr;
+	ba.vp = vp;
+	ba.os = tosnap;
+	ba.off = off;
+	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_dataset(ds, fromtxg, TRAVERSE_PRE | TRAVERSE_PREFETCH,
+	    backup_cb, &ba);
+
+	if (err) {
+		if (err == EINTR && ba.err)
+			err = ba.err;
+		kmem_free(drr, sizeof (dmu_replay_record_t));
+		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))) {
+		kmem_free(drr, sizeof (dmu_replay_record_t));
+		return (ba.err);
+	}
+
+	kmem_free(drr, sizeof (dmu_replay_record_t));
+
+	return (0);
+}
+
+struct recvbeginsyncarg {
+	const char *tofs;
+	const char *tosnap;
+	dsl_dataset_t *origin;
+	uint64_t fromguid;
+	dmu_objset_type_t type;
+	void *tag;
+	boolean_t force;
+	uint64_t dsflags;
+	char clonelastname[MAXNAMELEN];
+	dsl_dataset_t *ds; /* the ds to recv into; returned from the syncfunc */
+};
+
+static dsl_dataset_t *
+recv_full_sync_impl(dsl_pool_t *dp, uint64_t dsobj, dmu_objset_type_t type,
+    cred_t *cr, dmu_tx_t *tx)
+{
+	dsl_dataset_t *ds;
+
+	/* This should always work, since we just created it */
+	/* XXX - create should return an owned ds */
+	VERIFY(0 == dsl_dataset_own_obj(dp, dsobj,
+	    DS_MODE_INCONSISTENT, dmu_recv_tag, &ds));
+
+	if (type != DMU_OST_NONE) {
+		(void) dmu_objset_create_impl(dp->dp_spa,
+		    ds, &ds->ds_phys->ds_bp, type, tx);
+	}
+
+	spa_history_internal_log(LOG_DS_REPLAY_FULL_SYNC,
+	    dp->dp_spa, tx, cr, "dataset = %lld", dsobj);
+
+	return (ds);
+}
+
+/* ARGSUSED */
+static int
+recv_full_check(void *arg1, void *arg2, dmu_tx_t *tx)
+{
+	dsl_dir_t *dd = arg1;
+	struct recvbeginsyncarg *rbsa = arg2;
+	objset_t *mos = dd->dd_pool->dp_meta_objset;
+	uint64_t val;
+	int err;
+
+	err = zap_lookup(mos, dd->dd_phys->dd_child_dir_zapobj,
+	    strrchr(rbsa->tofs, '/') + 1, sizeof (uint64_t), 1, &val);
+
+	if (err != ENOENT)
+		return (err ? err : EEXIST);
+
+	if (rbsa->origin) {
+		/* make sure it's a snap in the same pool */
+		if (rbsa->origin->ds_dir->dd_pool != dd->dd_pool)
+			return (EXDEV);
+		if (rbsa->origin->ds_phys->ds_num_children == 0)
+			return (EINVAL);
+		if (rbsa->origin->ds_phys->ds_guid != rbsa->fromguid)
+			return (ENODEV);
+	}
+
+	return (0);
+}
+
+static void
+recv_full_sync(void *arg1, void *arg2, cred_t *cr, dmu_tx_t *tx)
+{
+	dsl_dir_t *dd = arg1;
+	struct recvbeginsyncarg *rbsa = arg2;
+	uint64_t flags = DS_FLAG_INCONSISTENT | rbsa->dsflags;
+	uint64_t dsobj;
+
+	dsobj = dsl_dataset_create_sync(dd, strrchr(rbsa->tofs, '/') + 1,
+	    rbsa->origin, flags, cr, tx);
+
+	rbsa->ds = recv_full_sync_impl(dd->dd_pool, dsobj,
+	    rbsa->origin ? DMU_OST_NONE : rbsa->type, cr, tx);
+}
+
+static int
+recv_full_existing_check(void *arg1, void *arg2, dmu_tx_t *tx)
+{
+	dsl_dataset_t *ds = arg1;
+	struct recvbeginsyncarg *rbsa = arg2;
+	int err;
+
+	/* must be a head ds */
+	if (ds->ds_phys->ds_next_snap_obj != 0)
+		return (EINVAL);
+
+	/* must not be a clone ds */
+	if (dsl_dir_is_clone(ds->ds_dir))
+		return (EINVAL);
+
+	err = dsl_dataset_destroy_check(ds, rbsa->tag, tx);
+	if (err)
+		return (err);
+
+	if (rbsa->origin) {
+		/* make sure it's a snap in the same pool */
+		if (rbsa->origin->ds_dir->dd_pool != ds->ds_dir->dd_pool)
+			return (EXDEV);
+		if (rbsa->origin->ds_phys->ds_num_children == 0)
+			return (EINVAL);
+		if (rbsa->origin->ds_phys->ds_guid != rbsa->fromguid)
+			return (ENODEV);
+	}
+
+	return (0);
+}
+
+static void
+recv_full_existing_sync(void *arg1, void *arg2, cred_t *cr, dmu_tx_t *tx)
+{
+	dsl_dataset_t *ds = arg1;
+	struct recvbeginsyncarg *rbsa = arg2;
+	dsl_dir_t *dd = ds->ds_dir;
+	uint64_t flags = DS_FLAG_INCONSISTENT | rbsa->dsflags;
+	uint64_t dsobj;
+
+	/*
+	 * NB: caller must provide an extra hold on the dsl_dir_t, so it
+	 * won't go away when dsl_dataset_destroy_sync() closes the
+	 * dataset.
+	 */
+	dsl_dataset_destroy_sync(ds, rbsa->tag, cr, tx);
+
+	dsobj = dsl_dataset_create_sync_dd(dd, rbsa->origin, flags, tx);
+
+	rbsa->ds = recv_full_sync_impl(dd->dd_pool, dsobj,
+	    rbsa->origin ? DMU_OST_NONE : rbsa->type, cr, tx);
+}
+
+/* ARGSUSED */
+static int
+recv_incremental_check(void *arg1, void *arg2, dmu_tx_t *tx)
+{
+	dsl_dataset_t *ds = arg1;
+	struct recvbeginsyncarg *rbsa = arg2;
+	int err;
+	uint64_t val;
+
+	/* must not have any changes since most recent snapshot */
+	if (!rbsa->force && dsl_dataset_modified_since_lastsnap(ds))
+		return (ETXTBSY);
+
+	/* 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 != rbsa->fromguid)
+		return (ENODEV);
+
+	/* temporary clone name must not exist */
+	err = zap_lookup(ds->ds_dir->dd_pool->dp_meta_objset,
+	    ds->ds_dir->dd_phys->dd_child_dir_zapobj,
+	    rbsa->clonelastname, 8, 1, &val);
+	if (err == 0)
+		return (EEXIST);
+	if (err != ENOENT)
+		return (err);
+
+	/* new snapshot name must not exist */
+	err = zap_lookup(ds->ds_dir->dd_pool->dp_meta_objset,
+	    ds->ds_phys->ds_snapnames_zapobj, rbsa->tosnap, 8, 1, &val);
+	if (err == 0)
+		return (EEXIST);
+	if (err != ENOENT)
+		return (err);
+	return (0);
+}
+
+/* ARGSUSED */
+static void
+recv_online_incremental_sync(void *arg1, void *arg2, cred_t *cr, dmu_tx_t *tx)
+{
+	dsl_dataset_t *ohds = arg1;
+	struct recvbeginsyncarg *rbsa = arg2;
+	dsl_pool_t *dp = ohds->ds_dir->dd_pool;
+	dsl_dataset_t *ods, *cds;
+	uint64_t flags = DS_FLAG_INCONSISTENT | rbsa->dsflags;
+	uint64_t dsobj;
+
+	/* create the temporary clone */
+	VERIFY(0 == dsl_dataset_hold_obj(dp, ohds->ds_phys->ds_prev_snap_obj,
+	    FTAG, &ods));
+	dsobj = dsl_dataset_create_sync(ohds->ds_dir,
+	    rbsa->clonelastname, ods, flags, cr, tx);
+	dsl_dataset_rele(ods, FTAG);
+
+	/* open the temporary clone */
+	VERIFY(0 == dsl_dataset_own_obj(dp, dsobj,
+	    DS_MODE_INCONSISTENT, dmu_recv_tag, &cds));
+
+	/* copy the refquota from the target fs to the clone */
+	if (ohds->ds_quota > 0)
+		dsl_dataset_set_quota_sync(cds, &ohds->ds_quota, cr, tx);
+
+	rbsa->ds = cds;
+
+	spa_history_internal_log(LOG_DS_REPLAY_INC_SYNC,
+	    dp->dp_spa, tx, cr, "dataset = %lld", dsobj);
+}
+
+/* ARGSUSED */
+static void
+recv_offline_incremental_sync(void *arg1, void *arg2, cred_t *cr, 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;
+
+	spa_history_internal_log(LOG_DS_REPLAY_INC_SYNC,
+	    ds->ds_dir->dd_pool->dp_spa, tx, cr, "dataset = %lld",
+	    ds->ds_object);
+}
+
+/*
+ * NB: callers *MUST* call dmu_recv_stream() if dmu_recv_begin()
+ * succeeds; otherwise we will leak the holds on the datasets.
+ */
+int
+dmu_recv_begin(char *tofs, char *tosnap, struct drr_begin *drrb,
+    boolean_t force, objset_t *origin, boolean_t online, dmu_recv_cookie_t *drc)
+{
+	int err = 0;
+	boolean_t byteswap;
+	struct recvbeginsyncarg rbsa;
+	uint64_t version;
+	int flags;
+	dsl_dataset_t *ds;
+
+	if (drrb->drr_magic == DMU_BACKUP_MAGIC)
+		byteswap = FALSE;
+	else if (drrb->drr_magic == BSWAP_64(DMU_BACKUP_MAGIC))
+		byteswap = TRUE;
+	else
+		return (EINVAL);
+
+	rbsa.tofs = tofs;
+	rbsa.tosnap = tosnap;
+	rbsa.origin = origin ? origin->os->os_dsl_dataset : NULL;
+	rbsa.fromguid = drrb->drr_fromguid;
+	rbsa.type = drrb->drr_type;
+	rbsa.tag = FTAG;
+	rbsa.dsflags = 0;
+	version = drrb->drr_version;
+	flags = drrb->drr_flags;
+
+	if (byteswap) {
+		rbsa.type = BSWAP_32(rbsa.type);
+		rbsa.fromguid = BSWAP_64(rbsa.fromguid);
+		version = BSWAP_64(version);
+		flags = BSWAP_32(flags);
+	}
+
+	if (version != DMU_BACKUP_STREAM_VERSION ||
+	    rbsa.type >= DMU_OST_NUMTYPES ||
+	    ((flags & DRR_FLAG_CLONE) && origin == NULL))
+		return (EINVAL);
+
+	if (flags & DRR_FLAG_CI_DATA)
+		rbsa.dsflags = DS_FLAG_CI_DATASET;
+
+	bzero(drc, sizeof (dmu_recv_cookie_t));
+	drc->drc_drrb = drrb;
+	drc->drc_tosnap = tosnap;
+	drc->drc_force = force;
+
+	/*
+	 * Process the begin in syncing context.
+	 */
+	if (rbsa.fromguid && !(flags & DRR_FLAG_CLONE) && !online) {
+		/* offline incremental receive */
+		err = dsl_dataset_own(tofs, 0, dmu_recv_tag, &ds);
+		if (err)
+			return (err);
+
+		/*
+		 * Only do the rollback if the most recent snapshot
+		 * matches the incremental source
+		 */
+		if (force) {
+			if (ds->ds_prev == NULL ||
+			    ds->ds_prev->ds_phys->ds_guid !=
+			    rbsa.fromguid) {
+				dsl_dataset_disown(ds, dmu_recv_tag);
+				return (ENODEV);
+			}
+			(void) dsl_dataset_rollback(ds, DMU_OST_NONE);
+		}
+		rbsa.force = B_FALSE;
+		err = dsl_sync_task_do(ds->ds_dir->dd_pool,
+		    recv_incremental_check,
+		    recv_offline_incremental_sync, ds, &rbsa, 1);
+		if (err) {
+			dsl_dataset_disown(ds, dmu_recv_tag);
+			return (err);
+		}
+		drc->drc_logical_ds = drc->drc_real_ds = ds;
+	} else if (rbsa.fromguid && !(flags & DRR_FLAG_CLONE)) {
+		/* online incremental receive */
+
+		/* tmp clone name is: tofs/%tosnap" */
+		(void) snprintf(rbsa.clonelastname, sizeof (rbsa.clonelastname),
+		    "%%%s", tosnap);
+
+		/* open the dataset we are logically receiving into */
+		err = dsl_dataset_hold(tofs, dmu_recv_tag, &ds);
+		if (err)
+			return (err);
+
+		rbsa.force = force;
+		err = dsl_sync_task_do(ds->ds_dir->dd_pool,
+		    recv_incremental_check,
+		    recv_online_incremental_sync, ds, &rbsa, 5);
+		if (err) {
+			dsl_dataset_rele(ds, dmu_recv_tag);
+			return (err);
+		}
+		drc->drc_logical_ds = ds;
+		drc->drc_real_ds = rbsa.ds;
+	} else {
+		/* create new fs -- full backup or clone */
+		dsl_dir_t *dd = NULL;
+		const char *tail;
+
+		err = dsl_dir_open(tofs, FTAG, &dd, &tail);
+		if (err)
+			return (err);
+		if (tail == NULL) {
+			if (!force) {
+				dsl_dir_close(dd, FTAG);
+				return (EEXIST);
+			}
+
+			rw_enter(&dd->dd_pool->dp_config_rwlock, RW_READER);
+			err = dsl_dataset_own_obj(dd->dd_pool,
+			    dd->dd_phys->dd_head_dataset_obj,
+			    DS_MODE_INCONSISTENT, FTAG, &ds);
+			rw_exit(&dd->dd_pool->dp_config_rwlock);
+			if (err) {
+				dsl_dir_close(dd, FTAG);
+				return (err);
+			}
+
+			dsl_dataset_make_exclusive(ds, FTAG);
+			err = dsl_sync_task_do(dd->dd_pool,
+			    recv_full_existing_check,
+			    recv_full_existing_sync, ds, &rbsa, 5);
+			dsl_dataset_disown(ds, FTAG);
+		} else {
+			err = dsl_sync_task_do(dd->dd_pool, recv_full_check,
+			    recv_full_sync, dd, &rbsa, 5);
+		}
+		dsl_dir_close(dd, FTAG);
+		if (err)
+			return (err);
+		drc->drc_logical_ds = drc->drc_real_ds = rbsa.ds;
+		drc->drc_newfs = B_TRUE;
+	}
+
+	return (0);
+}
+
+struct restorearg {
+	int err;
+	int byteswap;
+	vnode_t *vp;
+	char *buf;
+	uint64_t voff;
+	int bufsize; /* amount of memory allocated for buf */
+	zio_cksum_t cksum;
+};
+
+static void *
+restore_read(struct restorearg *ra, int len)
+{
+	void *rv;
+	int done = 0;
+
+	/* some things will require 8-byte alignment, so everything must */
+	ASSERT3U(len % 8, ==, 0);
+
+	while (done < len) {
+		ssize_t resid;
+
+		ra->err = vn_rdwr(UIO_READ, ra->vp,
+		    (caddr_t)ra->buf + done, len - done,
+		    ra->voff, UIO_SYSSPACE, FAPPEND,
+		    RLIM64_INFINITY, CRED(), &resid);
+
+		if (resid == len - done)
+			ra->err = EINVAL;
+		ra->voff += len - done - resid;
+		done = len - resid;
+		if (ra->err)
+			return (NULL);
+	}
+
+	ASSERT3U(done, ==, len);
+	rv = ra->buf;
+	if (ra->byteswap)
+		fletcher_4_incremental_byteswap(rv, len, &ra->cksum);
+	else
+		fletcher_4_incremental_native(rv, len, &ra->cksum);
+	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);
+	drr->drr_payloadlen = BSWAP_32(drr->drr_payloadlen);
+	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);
+		DO32(drr_begin.drr_flags);
+		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;
+	void *data = NULL;
+
+	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);
+	}
+
+	if (drro->drr_bonuslen) {
+		data = restore_read(ra, P2ROUNDUP(drro->drr_bonuslen, 8));
+		if (ra->err)
+			return (ra->err);
+	}
+
+	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 (data != NULL) {
+		dmu_buf_t *db;
+
+		VERIFY(0 == dmu_bonus_hold(os, drro->drr_object, FTAG, &db));
+		dmu_buf_will_dirty(db, tx);
+
+		ASSERT3U(db->db_size, >=, drro->drr_bonuslen);
+		bcopy(data, db->db_data, drro->drr_bonuslen);
+		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;
+	    (void) dmu_object_next(os, &obj, FALSE, 0)) {
+		int err;
+
+		if (dmu_object_info(os, obj, NULL) != 0)
+			continue;
+
+		err = dmu_free_object(os, obj);
+		if (err)
+			return (err);
+	}
+	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)
+{
+	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);
+
+	err = dmu_free_long_range(os, drrf->drr_object,
+	    drrf->drr_offset, drrf->drr_length);
+	return (err);
+}
+
+void
+dmu_recv_abort_cleanup(dmu_recv_cookie_t *drc)
+{
+	if (drc->drc_newfs || drc->drc_real_ds != drc->drc_logical_ds) {
+		/*
+		 * online incremental or new fs: destroy the fs (which
+		 * may be a clone) that we created
+		 */
+		(void) dsl_dataset_destroy(drc->drc_real_ds, dmu_recv_tag);
+		if (drc->drc_real_ds != drc->drc_logical_ds)
+			dsl_dataset_rele(drc->drc_logical_ds, dmu_recv_tag);
+	} else {
+		/*
+		 * offline incremental: rollback to most recent snapshot.
+		 */
+		(void) dsl_dataset_rollback(drc->drc_real_ds, DMU_OST_NONE);
+		dsl_dataset_disown(drc->drc_real_ds, dmu_recv_tag);
+	}
+}
+
+/*
+ * NB: callers *must* call dmu_recv_end() if this succeeds.
+ */
+int
+dmu_recv_stream(dmu_recv_cookie_t *drc, vnode_t *vp, offset_t *voffp)
+{
+	struct restorearg ra = { 0 };
+	dmu_replay_record_t *drr;
+	objset_t *os;
+	zio_cksum_t pcksum;
+
+	if (drc->drc_drrb->drr_magic == BSWAP_64(DMU_BACKUP_MAGIC))
+		ra.byteswap = TRUE;
+
+	{
+		/* compute checksum of drr_begin record */
+		dmu_replay_record_t *drr;
+		drr = kmem_zalloc(sizeof (dmu_replay_record_t), KM_SLEEP);
+
+		drr->drr_type = DRR_BEGIN;
+		drr->drr_u.drr_begin = *drc->drc_drrb;
+		if (ra.byteswap) {
+			fletcher_4_incremental_byteswap(drr,
+			    sizeof (dmu_replay_record_t), &ra.cksum);
+		} else {
+			fletcher_4_incremental_native(drr,
+			    sizeof (dmu_replay_record_t), &ra.cksum);
+		}
+		kmem_free(drr, sizeof (dmu_replay_record_t));
+	}
+
+	if (ra.byteswap) {
+		struct drr_begin *drrb = drc->drc_drrb;
+		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);
+	}
+
+	ra.vp = vp;
+	ra.voff = *voffp;
+	ra.bufsize = 1<<20;
+	ra.buf = kmem_alloc(ra.bufsize, KM_SLEEP);
+
+	/* these were verified in dmu_recv_begin */
+	ASSERT(drc->drc_drrb->drr_version == DMU_BACKUP_STREAM_VERSION);
+	ASSERT(drc->drc_drrb->drr_type < DMU_OST_NUMTYPES);
+
+	/*
+	 * Open the objset we are modifying.
+	 */
+	VERIFY(dmu_objset_open_ds(drc->drc_real_ds, DMU_OST_ANY, &os) == 0);
+
+	ASSERT(drc->drc_real_ds->ds_phys->ds_flags & DS_FLAG_INCONSISTENT);
+
+	/*
+	 * Read records and process them.
+	 */
+	pcksum = ra.cksum;
+	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 (!ZIO_CHECKSUM_EQUAL(drre.drr_checksum, pcksum))
+				ra.err = ECKSUM;
+			goto out;
+		}
+		default:
+			ra.err = EINVAL;
+			goto out;
+		}
+		pcksum = ra.cksum;
+	}
+	ASSERT(ra.err != 0);
+
+out:
+	dmu_objset_close(os);
+
+	if (ra.err != 0) {
+		/*
+		 * rollback or destroy what we created, so we don't
+		 * leave it in the restoring state.
+		 */
+		txg_wait_synced(drc->drc_real_ds->ds_dir->dd_pool, 0);
+		dmu_recv_abort_cleanup(drc);
+	}
+
+	kmem_free(ra.buf, ra.bufsize);
+	*voffp = ra.voff;
+	return (ra.err);
+}
+
+struct recvendsyncarg {
+	char *tosnap;
+	uint64_t creation_time;
+	uint64_t toguid;
+};
+
+static int
+recv_end_check(void *arg1, void *arg2, dmu_tx_t *tx)
+{
+	dsl_dataset_t *ds = arg1;
+	struct recvendsyncarg *resa = arg2;
+
+	return (dsl_dataset_snapshot_check(ds, resa->tosnap, tx));
+}
+
+static void
+recv_end_sync(void *arg1, void *arg2, cred_t *cr, dmu_tx_t *tx)
+{
+	dsl_dataset_t *ds = arg1;
+	struct recvendsyncarg *resa = arg2;
+
+	dsl_dataset_snapshot_sync(ds, resa->tosnap, cr, tx);
+
+	/* set snapshot's creation time and guid */
+	dmu_buf_will_dirty(ds->ds_prev->ds_dbuf, tx);
+	ds->ds_prev->ds_phys->ds_creation_time = resa->creation_time;
+	ds->ds_prev->ds_phys->ds_guid = resa->toguid;
+	ds->ds_prev->ds_phys->ds_flags &= ~DS_FLAG_INCONSISTENT;
+
+	dmu_buf_will_dirty(ds->ds_dbuf, tx);
+	ds->ds_phys->ds_flags &= ~DS_FLAG_INCONSISTENT;
+}
+
+int
+dmu_recv_end(dmu_recv_cookie_t *drc)
+{
+	struct recvendsyncarg resa;
+	dsl_dataset_t *ds = drc->drc_logical_ds;
+	int err;
+
+	/*
+	 * XXX hack; seems the ds is still dirty and
+	 * dsl_pool_zil_clean() expects it to have a ds_user_ptr
+	 * (and zil), but clone_swap() can close it.
+	 */
+	txg_wait_synced(ds->ds_dir->dd_pool, 0);
+
+	if (ds != drc->drc_real_ds) {
+		/* we are doing an online recv */
+		if (dsl_dataset_tryown(ds, FALSE, dmu_recv_tag)) {
+			err = dsl_dataset_clone_swap(drc->drc_real_ds, ds,
+			    drc->drc_force);
+			if (err)
+				dsl_dataset_disown(ds, dmu_recv_tag);
+		} else {
+			err = EBUSY;
+			dsl_dataset_rele(ds, dmu_recv_tag);
+		}
+		/* dsl_dataset_destroy() will disown the ds */
+		(void) dsl_dataset_destroy(drc->drc_real_ds, dmu_recv_tag);
+		if (err)
+			return (err);
+	}
+
+	resa.creation_time = drc->drc_drrb->drr_creation_time;
+	resa.toguid = drc->drc_drrb->drr_toguid;
+	resa.tosnap = drc->drc_tosnap;
+
+	err = dsl_sync_task_do(ds->ds_dir->dd_pool,
+	    recv_end_check, recv_end_sync, ds, &resa, 3);
+	if (err) {
+		if (drc->drc_newfs) {
+			ASSERT(ds == drc->drc_real_ds);
+			(void) dsl_dataset_destroy(ds, dmu_recv_tag);
+			return (err);
+		} else {
+			(void) dsl_dataset_rollback(ds, DMU_OST_NONE);
+		}
+	}
+
+	/* release the hold from dmu_recv_begin */
+	dsl_dataset_disown(ds, dmu_recv_tag);
+	return (err);
+}