Merge new ZFS features from illumos:

1644 add ZFS "clones" property
https://www.illumos.org/issues/1644

1645 add ZFS "written" and "written@..." properties
https://www.illumos.org/issues/1645

1646 "zfs send" should estimate size of stream
https://www.illumos.org/issues/1646

1647 "zfs destroy" should determine space reclaimed by destroying multiple
snapshots
https://www.illumos.org/issues/1647

1693 persistent 'comment' field for a zpool
https://www.illumos.org/issues/1693

1708 adjust size of zpool history data
https://www.illumos.org/issues/1708

1748 desire support for reguid in zfs
https://www.illumos.org/issues/1748

Obtained from:	illumos (changesets 13514, 13524, 13525)
MFC after:	1 month

24 files changed, 808 insertions, 118 deletions

diff --git a/sys/cddl/contrib/opensolaris/common/zfs/zfs_prop.c b/sys/cddl/contrib/opensolaris/common/zfs/zfs_prop.c
index baa5e49..398963a 100644
--- a/sys/cddl/contrib/opensolaris/common/zfs/zfs_prop.c
+++ b/sys/cddl/contrib/opensolaris/common/zfs/zfs_prop.c
@@ -267,7 +267,7 @@ zfs_prop_init(void)
 	/* default index properties */
 	zprop_register_index(ZFS_PROP_VERSION, "version", 0, PROP_DEFAULT,
 	    ZFS_TYPE_FILESYSTEM | ZFS_TYPE_SNAPSHOT,
-	    "1 | 2 | 3 | 4 | current", "VERSION", version_table);
+	    "1 | 2 | 3 | 4 | 5 | current", "VERSION", version_table);
 	zprop_register_index(ZFS_PROP_CANMOUNT, "canmount", ZFS_CANMOUNT_ON,
 	    PROP_DEFAULT, ZFS_TYPE_FILESYSTEM, "on | off | noauto",
 	    "CANMOUNT", canmount_table);
@@ -297,6 +297,8 @@ zfs_prop_init(void)
 	/* string properties */
 	zprop_register_string(ZFS_PROP_ORIGIN, "origin", NULL, PROP_READONLY,
 	    ZFS_TYPE_FILESYSTEM | ZFS_TYPE_VOLUME, "<snapshot>", "ORIGIN");
+	zprop_register_string(ZFS_PROP_CLONES, "clones", NULL, PROP_READONLY,
+	    ZFS_TYPE_SNAPSHOT, "<dataset>[,...]", "CLONES");
 	zprop_register_string(ZFS_PROP_MOUNTPOINT, "mountpoint", "/",
 	    PROP_INHERIT, ZFS_TYPE_FILESYSTEM, "<path> | legacy | none",
 	    "MOUNTPOINT");
@@ -342,6 +344,8 @@ zfs_prop_init(void)
 	    ZFS_TYPE_FILESYSTEM | ZFS_TYPE_VOLUME, "<size>", "USEDREFRESERV");
 	zprop_register_number(ZFS_PROP_USERREFS, "userrefs", 0, PROP_READONLY,
 	    ZFS_TYPE_SNAPSHOT, "<count>", "USERREFS");
+	zprop_register_number(ZFS_PROP_WRITTEN, "written", 0, PROP_READONLY,
+	    ZFS_TYPE_DATASET, "<size>", "WRITTEN");
 
 	/* default number properties */
 	zprop_register_number(ZFS_PROP_QUOTA, "quota", 0, PROP_DEFAULT,
@@ -468,6 +472,18 @@ zfs_prop_userquota(const char *name)
 }
 
 /*
+ * Returns true if this is a valid written@ property.
+ * Note that after the @, any character is valid (eg, another @, for
+ * written@pool/fs@origin).
+ */
+boolean_t
+zfs_prop_written(const char *name)
+{
+	static const char *prefix = "written@";
+	return (strncmp(name, prefix, strlen(prefix)) == 0);
+}
+
+/*
  * Tables of index types, plus functions to convert between the user view
  * (strings) and internal representation (uint64_t).
  */
diff --git a/sys/cddl/contrib/opensolaris/common/zfs/zfs_prop.h b/sys/cddl/contrib/opensolaris/common/zfs/zfs_prop.h
index a632623..e604abd 100644
--- a/sys/cddl/contrib/opensolaris/common/zfs/zfs_prop.h
+++ b/sys/cddl/contrib/opensolaris/common/zfs/zfs_prop.h
@@ -121,6 +121,8 @@ uint64_t zprop_random_value(int, uint64_t, zfs_type_t);
 const char *zprop_values(int, zfs_type_t);
 size_t zprop_width(int, boolean_t *, zfs_type_t);
 boolean_t zprop_valid_for_type(int, zfs_type_t);
+boolean_t zfs_prop_written(const char *name);
+
 
 #ifdef	__cplusplus
 }
diff --git a/sys/cddl/contrib/opensolaris/common/zfs/zpool_prop.c b/sys/cddl/contrib/opensolaris/common/zfs/zpool_prop.c
index 988d05d..add5bfb 100644
--- a/sys/cddl/contrib/opensolaris/common/zfs/zpool_prop.c
+++ b/sys/cddl/contrib/opensolaris/common/zfs/zpool_prop.c
@@ -20,6 +20,8 @@
  */
 /*
  * Copyright (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright 2011 Nexenta Systems, Inc. All rights reserved.
+ * Copyright (c) 2011 by Delphix. All rights reserved.
  */
 
 #include <sys/zio.h>
@@ -69,6 +71,8 @@ zpool_prop_init(void)
 	    ZFS_TYPE_POOL, "<filesystem>", "BOOTFS");
 	zprop_register_string(ZPOOL_PROP_CACHEFILE, "cachefile", NULL,
 	    PROP_DEFAULT, ZFS_TYPE_POOL, "<file> | none", "CACHEFILE");
+	zprop_register_string(ZPOOL_PROP_COMMENT, "comment", NULL,
+	    PROP_DEFAULT, ZFS_TYPE_POOL, "<comment-string>", "COMMENT");
 
 	/* readonly number properties */
 	zprop_register_number(ZPOOL_PROP_SIZE, "size", 0, PROP_READONLY,
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c
index 2adad8a..294c6fd 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c
@@ -20,6 +20,8 @@
  */
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
+ * Copyright (c) 2011 by Delphix. All rights reserved.
  */
 
 /*
@@ -1365,7 +1367,7 @@ arc_buf_alloc(spa_t *spa, int size, void *tag, arc_buf_contents_t type)
 	ASSERT(BUF_EMPTY(hdr));
 	hdr->b_size = size;
 	hdr->b_type = type;
-	hdr->b_spa = spa_guid(spa);
+	hdr->b_spa = spa_load_guid(spa);
 	hdr->b_state = arc_anon;
 	hdr->b_arc_access = 0;
 	buf = kmem_cache_alloc(buf_cache, KM_PUSHPAGE);
@@ -2146,7 +2148,7 @@ arc_flush(spa_t *spa)
 	uint64_t guid = 0;
 
 	if (spa)
-		guid = spa_guid(spa);
+		guid = spa_load_guid(spa);
 
 	while (arc_mru->arcs_lsize[ARC_BUFC_DATA]) {
 		(void) arc_evict(arc_mru, guid, -1, FALSE, ARC_BUFC_DATA);
@@ -2936,7 +2938,7 @@ arc_read_nolock(zio_t *pio, spa_t *spa, const blkptr_t *bp,
 	arc_buf_t *buf;
 	kmutex_t *hash_lock;
 	zio_t *rzio;
-	uint64_t guid = spa_guid(spa);
+	uint64_t guid = spa_load_guid(spa);
 
 top:
 	hdr = buf_hash_find(guid, BP_IDENTITY(bp), BP_PHYSICAL_BIRTH(bp),
@@ -4593,7 +4595,7 @@ l2arc_write_buffers(spa_t *spa, l2arc_dev_t *dev, uint64_t target_sz)
 	boolean_t have_lock, full;
 	l2arc_write_callback_t *cb;
 	zio_t *pio, *wzio;
-	uint64_t guid = spa_guid(spa);
+	uint64_t guid = spa_load_guid(spa);
 	int try;
 
 	ASSERT(dev->l2ad_vdev != NULL);
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/bpobj.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/bpobj.c
index 72be312..022921c 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/bpobj.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/bpobj.c
@@ -20,11 +20,13 @@
  */
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2011 by Delphix. All rights reserved.
  */
 
 #include <sys/bpobj.h>
 #include <sys/zfs_context.h>
 #include <sys/refcount.h>
+#include <sys/dsl_pool.h>
 
 uint64_t
 bpobj_alloc(objset_t *os, int blocksize, dmu_tx_t *tx)
@@ -440,7 +442,10 @@ space_range_cb(void *arg, const blkptr_t *bp, dmu_tx_t *tx)
 	struct space_range_arg *sra = arg;
 
 	if (bp->blk_birth > sra->mintxg && bp->blk_birth <= sra->maxtxg) {
-		sra->used += bp_get_dsize_sync(sra->spa, bp);
+		if (dsl_pool_sync_context(spa_get_dsl(sra->spa)))
+			sra->used += bp_get_dsize_sync(sra->spa, bp);
+		else
+			sra->used += bp_get_dsize(sra->spa, bp);
 		sra->comp += BP_GET_PSIZE(bp);
 		sra->uncomp += BP_GET_UCSIZE(bp);
 	}
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_send.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_send.c
index 42ef7d1..5b99b30 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_send.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_send.c
@@ -20,9 +20,11 @@
  */
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2011 by Delphix. All rights reserved.
  */
 /*
  * Copyright 2011 Nexenta Systems, Inc. All rights reserved.
+ * Copyright (c) 2011 by Delphix. All rights reserved.
  */
 
 #include <sys/dmu.h>
@@ -47,6 +49,9 @@
 #include <sys/ddt.h>
 #include <sys/zfs_onexit.h>
 
+/* Set this tunable to TRUE to replace corrupt data with 0x2f5baddb10c */
+int zfs_send_corrupt_data = B_FALSE;
+
 static char *dmu_recv_tag = "dmu_recv_tag";
 
 /*
@@ -384,8 +389,20 @@ backup_cb(spa_t *spa, zilog_t *zilog, const blkptr_t *bp, arc_buf_t *pbuf,
 
 		if (dsl_read(NULL, spa, bp, pbuf,
 		    arc_getbuf_func, &abuf, ZIO_PRIORITY_ASYNC_READ,
-		    ZIO_FLAG_CANFAIL, &aflags, zb) != 0)
-			return (EIO);
+		    ZIO_FLAG_CANFAIL, &aflags, zb) != 0) {
+			if (zfs_send_corrupt_data) {
+				/* Send a block filled with 0x"zfs badd bloc" */
+				abuf = arc_buf_alloc(spa, blksz, &abuf,
+				    ARC_BUFC_DATA);
+				uint64_t *ptr;
+				for (ptr = abuf->b_data;
+				    (char *)ptr < (char *)abuf->b_data + blksz;
+				    ptr++)
+					*ptr = 0x2f5baddb10c;
+			} else {
+				return (EIO);
+			}
+		}
 
 		err = dump_data(ba, type, zb->zb_object, zb->zb_blkid * blksz,
 		    blksz, bp, abuf->b_data);
@@ -515,6 +532,86 @@ dmu_sendbackup(objset_t *tosnap, objset_t *fromsnap, boolean_t fromorigin,
 	return (0);
 }
 
+int
+dmu_send_estimate(objset_t *tosnap, objset_t *fromsnap, boolean_t fromorigin,
+    uint64_t *sizep)
+{
+	dsl_dataset_t *ds = tosnap->os_dsl_dataset;
+	dsl_dataset_t *fromds = fromsnap ? fromsnap->os_dsl_dataset : NULL;
+	dsl_pool_t *dp = ds->ds_dir->dd_pool;
+	int err;
+	uint64_t size;
+
+	/* 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) {
+		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;
+		}
+	}
+
+	/* Get uncompressed size estimate of changed data. */
+	if (fromds == NULL) {
+		size = ds->ds_phys->ds_uncompressed_bytes;
+	} else {
+		uint64_t used, comp;
+		err = dsl_dataset_space_written(fromds, ds,
+		    &used, &comp, &size);
+		if (fromorigin)
+			dsl_dataset_rele(fromds, FTAG);
+		if (err)
+			return (err);
+	}
+
+	/*
+	 * Assume that space (both on-disk and in-stream) is dominated by
+	 * data.  We will adjust for indirect blocks and the copies property,
+	 * but ignore per-object space used (eg, dnodes and DRR_OBJECT records).
+	 */
+
+	/*
+	 * Subtract out approximate space used by indirect blocks.
+	 * Assume most space is used by data blocks (non-indirect, non-dnode).
+	 * Assume all blocks are recordsize.  Assume ditto blocks and
+	 * internal fragmentation counter out compression.
+	 *
+	 * Therefore, space used by indirect blocks is sizeof(blkptr_t) per
+	 * block, which we observe in practice.
+	 */
+	uint64_t recordsize;
+	rw_enter(&dp->dp_config_rwlock, RW_READER);
+	err = dsl_prop_get_ds(ds, "recordsize",
+	    sizeof (recordsize), 1, &recordsize, NULL);
+	rw_exit(&dp->dp_config_rwlock);
+	if (err)
+		return (err);
+	size -= size / recordsize * sizeof (blkptr_t);
+
+	/* Add in the space for the record associated with each block. */
+	size += size / recordsize * sizeof (dmu_replay_record_t);
+
+	*sizep = size;
+
+	return (0);
+}
+
 struct recvbeginsyncarg {
 	const char *tofs;
 	const char *tosnap;
@@ -1540,7 +1637,7 @@ dmu_recv_existing_end(dmu_recv_cookie_t *drc)
 {
 	struct recvendsyncarg resa;
 	dsl_dataset_t *ds = drc->drc_logical_ds;
-	int err;
+	int err, myerr;
 
 	/*
 	 * XXX hack; seems the ds is still dirty and dsl_pool_zil_clean()
@@ -1578,7 +1675,8 @@ out:
 	if (err == 0 && drc->drc_guid_to_ds_map != NULL)
 		(void) add_ds_to_guidmap(drc->drc_guid_to_ds_map, ds);
 	dsl_dataset_disown(ds, dmu_recv_tag);
-	(void) dsl_dataset_destroy(drc->drc_real_ds, dmu_recv_tag, B_FALSE);
+	myerr = dsl_dataset_destroy(drc->drc_real_ds, dmu_recv_tag, B_FALSE);
+	ASSERT3U(myerr, ==, 0);
 	return (err);
 }
 
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_dataset.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_dataset.c
index a306bb6..5101f87 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_dataset.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_dataset.c
@@ -23,6 +23,7 @@
  * Copyright (c) 2011 by Delphix. All rights reserved.
  * Copyright (c) 2011 Pawel Jakub Dawidek <pawel@dawidek.net>.
  * All rights reserved.
+ * Portions Copyright 2011 Martin Matuska <mm@FreeBSd.org>
  */
 
 #include <sys/dmu_objset.h>
@@ -908,69 +909,95 @@ dsl_dataset_create_sync(dsl_dir_t *pdd, const char *lastname,
 	return (dsobj);
 }
 
+#ifdef __FreeBSD__
+/* FreeBSD ioctl compat begin */
 struct destroyarg {
-	dsl_sync_task_group_t *dstg;
-	char *snapname;
-	char *failed;
-	boolean_t defer;
+	nvlist_t *nvl;
+	const char *snapname;
 };
 
 static int
-dsl_snapshot_destroy_one(const char *name, void *arg)
+dsl_check_snap_cb(const char *name, void *arg)
 {
 	struct destroyarg *da = arg;
 	dsl_dataset_t *ds;
-	int err;
 	char *dsname;
 
 	dsname = kmem_asprintf("%s@%s", name, da->snapname);
-	err = dsl_dataset_own(dsname, B_TRUE, da->dstg, &ds);
-	strfree(dsname);
-	if (err == 0) {
-		struct dsl_ds_destroyarg *dsda;
-
-		dsl_dataset_make_exclusive(ds, da->dstg);
-		dsda = kmem_zalloc(sizeof (struct dsl_ds_destroyarg), KM_SLEEP);
-		dsda->ds = ds;
-		dsda->defer = da->defer;
-		dsl_sync_task_create(da->dstg, dsl_dataset_destroy_check,
-		    dsl_dataset_destroy_sync, dsda, da->dstg, 0);
-	} else if (err == ENOENT) {
-		err = 0;
-	} else {
-		(void) strcpy(da->failed, name);
-	}
+	VERIFY(nvlist_add_boolean(da->nvl, dsname) == 0);
+
+	return (0);
+}
+
+int
+dmu_get_recursive_snaps_nvl(const char *fsname, const char *snapname,
+    nvlist_t *snaps)
+{
+	struct destroyarg *da;
+	int err;
+
+	da = kmem_zalloc(sizeof (struct destroyarg), KM_SLEEP);
+	da->nvl = snaps;
+	da->snapname = snapname;
+	err = dmu_objset_find(fsname, dsl_check_snap_cb, da,
+	    DS_FIND_CHILDREN);
+	kmem_free(da, sizeof (struct destroyarg));
+
 	return (err);
 }
+/* FreeBSD ioctl compat end */
+#endif /* __FreeBSD__ */
 
 /*
- * Destroy 'snapname' in all descendants of 'fsname'.
+ * The snapshots must all be in the same pool.
  */
-#pragma weak dmu_snapshots_destroy = dsl_snapshots_destroy
 int
-dsl_snapshots_destroy(char *fsname, char *snapname, boolean_t defer)
+dmu_snapshots_destroy_nvl(nvlist_t *snaps, boolean_t defer, char *failed)
 {
 	int err;
-	struct destroyarg da;
 	dsl_sync_task_t *dst;
 	spa_t *spa;
+	nvpair_t *pair;
+	dsl_sync_task_group_t *dstg;
 
-	err = spa_open(fsname, &spa, FTAG);
+	pair = nvlist_next_nvpair(snaps, NULL);
+	if (pair == NULL)
+		return (0);
+
+	err = spa_open(nvpair_name(pair), &spa, FTAG);
 	if (err)
 		return (err);
-	da.dstg = dsl_sync_task_group_create(spa_get_dsl(spa));
-	da.snapname = snapname;
-	da.failed = fsname;
-	da.defer = defer;
+	dstg = dsl_sync_task_group_create(spa_get_dsl(spa));
 
-	err = dmu_objset_find(fsname,
-	    dsl_snapshot_destroy_one, &da, DS_FIND_CHILDREN);
+	for (pair = nvlist_next_nvpair(snaps, NULL); pair != NULL;
+	    pair = nvlist_next_nvpair(snaps, pair)) {
+		dsl_dataset_t *ds;
+		int err;
+
+		err = dsl_dataset_own(nvpair_name(pair), B_TRUE, dstg, &ds);
+		if (err == 0) {
+			struct dsl_ds_destroyarg *dsda;
+
+			dsl_dataset_make_exclusive(ds, dstg);
+			dsda = kmem_zalloc(sizeof (struct dsl_ds_destroyarg),
+			    KM_SLEEP);
+			dsda->ds = ds;
+			dsda->defer = defer;
+			dsl_sync_task_create(dstg, dsl_dataset_destroy_check,
+			    dsl_dataset_destroy_sync, dsda, dstg, 0);
+		} else if (err == ENOENT) {
+			err = 0;
+		} else {
+			(void) strcpy(failed, nvpair_name(pair));
+			break;
+		}
+	}
 
 	if (err == 0)
-		err = dsl_sync_task_group_wait(da.dstg);
+		err = dsl_sync_task_group_wait(dstg);
 
-	for (dst = list_head(&da.dstg->dstg_tasks); dst;
-	    dst = list_next(&da.dstg->dstg_tasks, dst)) {
+	for (dst = list_head(&dstg->dstg_tasks); dst;
+	    dst = list_next(&dstg->dstg_tasks, dst)) {
 		struct dsl_ds_destroyarg *dsda = dst->dst_arg1;
 		dsl_dataset_t *ds = dsda->ds;
 
@@ -978,17 +1005,17 @@ dsl_snapshots_destroy(char *fsname, char *snapname, boolean_t defer)
 		 * Return the file system name that triggered the error
 		 */
 		if (dst->dst_err) {
-			dsl_dataset_name(ds, fsname);
-			*strchr(fsname, '@') = '\0';
+			dsl_dataset_name(ds, failed);
 		}
 		ASSERT3P(dsda->rm_origin, ==, NULL);
-		dsl_dataset_disown(ds, da.dstg);
+		dsl_dataset_disown(ds, dstg);
 		kmem_free(dsda, sizeof (struct dsl_ds_destroyarg));
 	}
 
-	dsl_sync_task_group_destroy(da.dstg);
+	dsl_sync_task_group_destroy(dstg);
 	spa_close(spa, FTAG);
 	return (err);
+
 }
 
 static boolean_t
@@ -2150,6 +2177,55 @@ dsl_dataset_sync(dsl_dataset_t *ds, zio_t *zio, dmu_tx_t *tx)
 	dmu_objset_sync(ds->ds_objset, zio, tx);
 }
 
+static void
+get_clones_stat(dsl_dataset_t *ds, nvlist_t *nv)
+{
+	uint64_t count = 0;
+	objset_t *mos = ds->ds_dir->dd_pool->dp_meta_objset;
+	zap_cursor_t zc;
+	zap_attribute_t za;
+	nvlist_t *propval;
+	nvlist_t *val;
+
+	rw_enter(&ds->ds_dir->dd_pool->dp_config_rwlock, RW_READER);
+	VERIFY(nvlist_alloc(&propval, NV_UNIQUE_NAME, KM_SLEEP) == 0);
+	VERIFY(nvlist_alloc(&val, NV_UNIQUE_NAME, KM_SLEEP) == 0);
+
+	/*
+	 * There may me missing entries in ds_next_clones_obj
+	 * due to a bug in a previous version of the code.
+	 * Only trust it if it has the right number of entries.
+	 */
+	if (ds->ds_phys->ds_next_clones_obj != 0) {
+		ASSERT3U(0, ==, zap_count(mos, ds->ds_phys->ds_next_clones_obj,
+		    &count));
+	}
+	if (count != ds->ds_phys->ds_num_children - 1) {
+		goto fail;
+	}
+	for (zap_cursor_init(&zc, mos, ds->ds_phys->ds_next_clones_obj);
+	    zap_cursor_retrieve(&zc, &za) == 0;
+	    zap_cursor_advance(&zc)) {
+		dsl_dataset_t *clone;
+		char buf[ZFS_MAXNAMELEN];
+		if (dsl_dataset_hold_obj(ds->ds_dir->dd_pool,
+		    za.za_first_integer, FTAG, &clone) != 0) {
+			goto fail;
+		}
+		dsl_dir_name(clone->ds_dir, buf);
+		VERIFY(nvlist_add_boolean(val, buf) == 0);
+		dsl_dataset_rele(clone, FTAG);
+	}
+	zap_cursor_fini(&zc);
+	VERIFY(nvlist_add_nvlist(propval, ZPROP_VALUE, val) == 0);
+	VERIFY(nvlist_add_nvlist(nv, zfs_prop_to_name(ZFS_PROP_CLONES),
+	    propval) == 0);
+fail:
+	nvlist_free(val);
+	nvlist_free(propval);
+	rw_exit(&ds->ds_dir->dd_pool->dp_config_rwlock);
+}
+
 void
 dsl_dataset_stats(dsl_dataset_t *ds, nvlist_t *nv)
 {
@@ -2180,6 +2256,26 @@ dsl_dataset_stats(dsl_dataset_t *ds, nvlist_t *nv)
 	dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_DEFER_DESTROY,
 	    DS_IS_DEFER_DESTROY(ds) ? 1 : 0);
 
+	if (ds->ds_phys->ds_prev_snap_obj != 0) {
+		uint64_t written, comp, uncomp;
+		dsl_pool_t *dp = ds->ds_dir->dd_pool;
+		dsl_dataset_t *prev;
+
+		rw_enter(&dp->dp_config_rwlock, RW_READER);
+		int err = dsl_dataset_hold_obj(dp,
+		    ds->ds_phys->ds_prev_snap_obj, FTAG, &prev);
+		rw_exit(&dp->dp_config_rwlock);
+		if (err == 0) {
+			err = dsl_dataset_space_written(prev, ds, &written,
+			    &comp, &uncomp);
+			dsl_dataset_rele(prev, FTAG);
+			if (err == 0) {
+				dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_WRITTEN,
+				    written);
+			}
+		}
+	}
+
 	ratio = ds->ds_phys->ds_compressed_bytes == 0 ? 100 :
 	    (ds->ds_phys->ds_uncompressed_bytes * 100 /
 	    ds->ds_phys->ds_compressed_bytes);
@@ -2193,6 +2289,8 @@ dsl_dataset_stats(dsl_dataset_t *ds, nvlist_t *nv)
 		dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_USED,
 		    ds->ds_phys->ds_unique_bytes);
 		dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_COMPRESSRATIO, ratio);
+
+		get_clones_stat(ds, nv);
 	}
 }
 
@@ -4025,7 +4123,7 @@ dsl_dataset_get_holds(const char *dsname, nvlist_t **nvp)
 }
 
 /*
- * Note, this fuction is used as the callback for dmu_objset_find().  We
+ * Note, this function is used as the callback for dmu_objset_find().  We
  * always return 0 so that we will continue to find and process
  * inconsistent datasets, even if we encounter an error trying to
  * process one of them.
@@ -4044,3 +4142,151 @@ dsl_destroy_inconsistent(const char *dsname, void *arg)
 	}
 	return (0);
 }
+
+/*
+ * Return (in *usedp) the amount of space written in new that is not
+ * present in oldsnap.  New may be a snapshot or the head.  Old must be
+ * a snapshot before new, in new's filesystem (or its origin).  If not then
+ * fail and return EINVAL.
+ *
+ * The written space is calculated by considering two components:  First, we
+ * ignore any freed space, and calculate the written as new's used space
+ * minus old's used space.  Next, we add in the amount of space that was freed
+ * between the two snapshots, thus reducing new's used space relative to old's.
+ * Specifically, this is the space that was born before old->ds_creation_txg,
+ * and freed before new (ie. on new's deadlist or a previous deadlist).
+ *
+ * space freed                         [---------------------]
+ * snapshots                       ---O-------O--------O-------O------
+ *                                         oldsnap            new
+ */
+int
+dsl_dataset_space_written(dsl_dataset_t *oldsnap, dsl_dataset_t *new,
+    uint64_t *usedp, uint64_t *compp, uint64_t *uncompp)
+{
+	int err = 0;
+	uint64_t snapobj;
+	dsl_pool_t *dp = new->ds_dir->dd_pool;
+
+	*usedp = 0;
+	*usedp += new->ds_phys->ds_used_bytes;
+	*usedp -= oldsnap->ds_phys->ds_used_bytes;
+
+	*compp = 0;
+	*compp += new->ds_phys->ds_compressed_bytes;
+	*compp -= oldsnap->ds_phys->ds_compressed_bytes;
+
+	*uncompp = 0;
+	*uncompp += new->ds_phys->ds_uncompressed_bytes;
+	*uncompp -= oldsnap->ds_phys->ds_uncompressed_bytes;
+
+	rw_enter(&dp->dp_config_rwlock, RW_READER);
+	snapobj = new->ds_object;
+	while (snapobj != oldsnap->ds_object) {
+		dsl_dataset_t *snap;
+		uint64_t used, comp, uncomp;
+
+		err = dsl_dataset_hold_obj(dp, snapobj, FTAG, &snap);
+		if (err != 0)
+			break;
+
+		if (snap->ds_phys->ds_prev_snap_txg ==
+		    oldsnap->ds_phys->ds_creation_txg) {
+			/*
+			 * The blocks in the deadlist can not be born after
+			 * ds_prev_snap_txg, so get the whole deadlist space,
+			 * which is more efficient (especially for old-format
+			 * deadlists).  Unfortunately the deadlist code
+			 * doesn't have enough information to make this
+			 * optimization itself.
+			 */
+			dsl_deadlist_space(&snap->ds_deadlist,
+			    &used, &comp, &uncomp);
+		} else {
+			dsl_deadlist_space_range(&snap->ds_deadlist,
+			    0, oldsnap->ds_phys->ds_creation_txg,
+			    &used, &comp, &uncomp);
+		}
+		*usedp += used;
+		*compp += comp;
+		*uncompp += uncomp;
+
+		/*
+		 * If we get to the beginning of the chain of snapshots
+		 * (ds_prev_snap_obj == 0) before oldsnap, then oldsnap
+		 * was not a snapshot of/before new.
+		 */
+		snapobj = snap->ds_phys->ds_prev_snap_obj;
+		dsl_dataset_rele(snap, FTAG);
+		if (snapobj == 0) {
+			err = EINVAL;
+			break;
+		}
+
+	}
+	rw_exit(&dp->dp_config_rwlock);
+	return (err);
+}
+
+/*
+ * Return (in *usedp) the amount of space that will be reclaimed if firstsnap,
+ * lastsnap, and all snapshots in between are deleted.
+ *
+ * blocks that would be freed            [---------------------------]
+ * snapshots                       ---O-------O--------O-------O--------O
+ *                                        firstsnap        lastsnap
+ *
+ * This is the set of blocks that were born after the snap before firstsnap,
+ * (birth > firstsnap->prev_snap_txg) and died before the snap after the
+ * last snap (ie, is on lastsnap->ds_next->ds_deadlist or an earlier deadlist).
+ * We calculate this by iterating over the relevant deadlists (from the snap
+ * after lastsnap, backward to the snap after firstsnap), summing up the
+ * space on the deadlist that was born after the snap before firstsnap.
+ */
+int
+dsl_dataset_space_wouldfree(dsl_dataset_t *firstsnap,
+    dsl_dataset_t *lastsnap,
+    uint64_t *usedp, uint64_t *compp, uint64_t *uncompp)
+{
+	int err = 0;
+	uint64_t snapobj;
+	dsl_pool_t *dp = firstsnap->ds_dir->dd_pool;
+
+	ASSERT(dsl_dataset_is_snapshot(firstsnap));
+	ASSERT(dsl_dataset_is_snapshot(lastsnap));
+
+	/*
+	 * Check that the snapshots are in the same dsl_dir, and firstsnap
+	 * is before lastsnap.
+	 */
+	if (firstsnap->ds_dir != lastsnap->ds_dir ||
+	    firstsnap->ds_phys->ds_creation_txg >
+	    lastsnap->ds_phys->ds_creation_txg)
+		return (EINVAL);
+
+	*usedp = *compp = *uncompp = 0;
+
+	rw_enter(&dp->dp_config_rwlock, RW_READER);
+	snapobj = lastsnap->ds_phys->ds_next_snap_obj;
+	while (snapobj != firstsnap->ds_object) {
+		dsl_dataset_t *ds;
+		uint64_t used, comp, uncomp;
+
+		err = dsl_dataset_hold_obj(dp, snapobj, FTAG, &ds);
+		if (err != 0)
+			break;
+
+		dsl_deadlist_space_range(&ds->ds_deadlist,
+		    firstsnap->ds_phys->ds_prev_snap_txg, UINT64_MAX,
+		    &used, &comp, &uncomp);
+		*usedp += used;
+		*compp += comp;
+		*uncompp += uncomp;
+
+		snapobj = ds->ds_phys->ds_prev_snap_obj;
+		ASSERT3U(snapobj, !=, 0);
+		dsl_dataset_rele(ds, FTAG);
+	}
+	rw_exit(&dp->dp_config_rwlock);
+	return (err);
+}
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_deadlist.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_deadlist.c
index 064f8ac..dd6db21 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_deadlist.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_deadlist.c
@@ -20,6 +20,7 @@
  */
 /*
  * Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2011 by Delphix. All rights reserved.
  */
 
 #include <sys/dsl_dataset.h>
@@ -29,6 +30,26 @@
 #include <sys/zfs_context.h>
 #include <sys/dsl_pool.h>
 
+/*
+ * Deadlist concurrency:
+ *
+ * Deadlists can only be modified from the syncing thread.
+ *
+ * Except for dsl_deadlist_insert(), it can only be modified with the
+ * dp_config_rwlock held with RW_WRITER.
+ *
+ * The accessors (dsl_deadlist_space() and dsl_deadlist_space_range()) can
+ * be called concurrently, from open context, with the dl_config_rwlock held
+ * with RW_READER.
+ *
+ * Therefore, we only need to provide locking between dsl_deadlist_insert() and
+ * the accessors, protecting:
+ *     dl_phys->dl_used,comp,uncomp
+ *     and protecting the dl_tree from being loaded.
+ * The locking is provided by dl_lock.  Note that locking on the bpobj_t
+ * provides its own locking, and dl_oldfmt is immutable.
+ */
+
 static int
 dsl_deadlist_compare(const void *arg1, const void *arg2)
 {
@@ -309,14 +330,14 @@ dsl_deadlist_space(dsl_deadlist_t *dl,
  * return space used in the range (mintxg, maxtxg].
  * Includes maxtxg, does not include mintxg.
  * mintxg and maxtxg must both be keys in the deadlist (unless maxtxg is
- * UINT64_MAX).
+ * larger than any bp in the deadlist (eg. UINT64_MAX)).
  */
 void
 dsl_deadlist_space_range(dsl_deadlist_t *dl, uint64_t mintxg, uint64_t maxtxg,
     uint64_t *usedp, uint64_t *compp, uint64_t *uncompp)
 {
-	dsl_deadlist_entry_t dle_tofind;
 	dsl_deadlist_entry_t *dle;
+	dsl_deadlist_entry_t dle_tofind;
 	avl_index_t where;
 
 	if (dl->dl_oldfmt) {
@@ -325,9 +346,10 @@ dsl_deadlist_space_range(dsl_deadlist_t *dl, uint64_t mintxg, uint64_t maxtxg,
 		return;
 	}
 
-	dsl_deadlist_load_tree(dl);
 	*usedp = *compp = *uncompp = 0;
 
+	mutex_enter(&dl->dl_lock);
+	dsl_deadlist_load_tree(dl);
 	dle_tofind.dle_mintxg = mintxg;
 	dle = avl_find(&dl->dl_tree, &dle_tofind, &where);
 	/*
@@ -336,6 +358,7 @@ dsl_deadlist_space_range(dsl_deadlist_t *dl, uint64_t mintxg, uint64_t maxtxg,
 	 */
 	ASSERT(dle != NULL ||
 	    avl_nearest(&dl->dl_tree, where, AVL_AFTER) == NULL);
+
 	for (; dle && dle->dle_mintxg < maxtxg;
 	    dle = AVL_NEXT(&dl->dl_tree, dle)) {
 		uint64_t used, comp, uncomp;
@@ -347,6 +370,7 @@ dsl_deadlist_space_range(dsl_deadlist_t *dl, uint64_t mintxg, uint64_t maxtxg,
 		*compp += comp;
 		*uncompp += uncomp;
 	}
+	mutex_exit(&dl->dl_lock);
 }
 
 static void
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_deleg.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_deleg.c
index b85c373..0b5fa0b 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_deleg.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_deleg.c
@@ -20,6 +20,7 @@
  */
 /*
  * Copyright (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2011 by Delphix. All rights reserved.
  */
 
 /*
@@ -525,10 +526,12 @@ dsl_load_user_sets(objset_t *mos, uint64_t zapobj, avl_tree_t *avl,
 }
 
 /*
- * Check if user has requested permission.
+ * Check if user has requested permission.  If descendent is set, must have
+ * descendent perms.
  */
 int
-dsl_deleg_access_impl(dsl_dataset_t *ds, const char *perm, cred_t *cr)
+dsl_deleg_access_impl(dsl_dataset_t *ds, boolean_t descendent, const char *perm,
+    cred_t *cr)
 {
 	dsl_dir_t *dd;
 	dsl_pool_t *dp;
@@ -549,7 +552,7 @@ dsl_deleg_access_impl(dsl_dataset_t *ds, const char *perm, cred_t *cr)
 	    SPA_VERSION_DELEGATED_PERMS)
 		return (EPERM);
 
-	if (dsl_dataset_is_snapshot(ds)) {
+	if (dsl_dataset_is_snapshot(ds) || descendent) {
 		/*
 		 * Snapshots are treated as descendents only,
 		 * local permissions do not apply.
@@ -642,7 +645,7 @@ dsl_deleg_access(const char *dsname, const char *perm, cred_t *cr)
 	if (error)
 		return (error);
 
-	error = dsl_deleg_access_impl(ds, perm, cr);
+	error = dsl_deleg_access_impl(ds, B_FALSE, perm, cr);
 	dsl_dataset_rele(ds, FTAG);
 
 	return (error);
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_pool.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_pool.c
index ea5e60d..7f7a3b9 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_pool.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_pool.c
@@ -20,6 +20,7 @@
  */
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2011 by Delphix. All rights reserved.
  */
 
 #include <sys/dsl_pool.h>
@@ -316,7 +317,10 @@ static int
 deadlist_enqueue_cb(void *arg, const blkptr_t *bp, dmu_tx_t *tx)
 {
 	dsl_deadlist_t *dl = arg;
+	dsl_pool_t *dp = dmu_objset_pool(dl->dl_os);
+	rw_enter(&dp->dp_config_rwlock, RW_READER);
 	dsl_deadlist_insert(dl, bp, tx);
+	rw_exit(&dp->dp_config_rwlock);
 	return (0);
 }
 
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa.c
index 9336a6b..8da471b 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa.c
@@ -21,6 +21,7 @@
 
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2011 by Delphix. All rights reserved.
  */
 
 /*
@@ -212,6 +213,11 @@ spa_prop_get_config(spa_t *spa, nvlist_t **nvp)
 
 	spa_prop_add_list(*nvp, ZPOOL_PROP_GUID, NULL, spa_guid(spa), src);
 
+	if (spa->spa_comment != NULL) {
+		spa_prop_add_list(*nvp, ZPOOL_PROP_COMMENT, spa->spa_comment,
+		    0, ZPROP_SRC_LOCAL);
+	}
+
 	if (spa->spa_root != NULL)
 		spa_prop_add_list(*nvp, ZPOOL_PROP_ALTROOT, spa->spa_root,
 		    0, ZPROP_SRC_LOCAL);
@@ -351,7 +357,7 @@ spa_prop_validate(spa_t *spa, nvlist_t *props)
 		char *propname, *strval;
 		uint64_t intval;
 		objset_t *os;
-		char *slash;
+		char *slash, *check;
 
 		propname = nvpair_name(elem);
 
@@ -471,6 +477,26 @@ spa_prop_validate(spa_t *spa, nvlist_t *props)
 				error = EINVAL;
 			break;
 
+		case ZPOOL_PROP_COMMENT:
+			if ((error = nvpair_value_string(elem, &strval)) != 0)
+				break;
+			for (check = strval; *check != '\0'; check++) {
+				/*
+				 * The kernel doesn't have an easy isprint()
+				 * check.  For this kernel check, we merely
+				 * check ASCII apart from DEL.  Fix this if
+				 * there is an easy-to-use kernel isprint().
+				 */
+				if (*check >= 0x7f) {
+					error = EINVAL;
+					break;
+				}
+				check++;
+			}
+			if (strlen(strval) > ZPROP_MAX_COMMENT)
+				error = E2BIG;
+			break;
+
 		case ZPOOL_PROP_DEDUPDITTO:
 			if (spa_version(spa) < SPA_VERSION_DEDUP)
 				error = ENOTSUP;
@@ -572,6 +598,43 @@ spa_prop_clear_bootfs(spa_t *spa, uint64_t dsobj, dmu_tx_t *tx)
 }
 
 /*
+ * Change the GUID for the pool.  This is done so that we can later
+ * re-import a pool built from a clone of our own vdevs.  We will modify
+ * the root vdev's guid, our own pool guid, and then mark all of our
+ * vdevs dirty.  Note that we must make sure that all our vdevs are
+ * online when we do this, or else any vdevs that weren't present
+ * would be orphaned from our pool.  We are also going to issue a
+ * sysevent to update any watchers.
+ */
+int
+spa_change_guid(spa_t *spa)
+{
+	uint64_t	oldguid, newguid;
+	uint64_t	txg;
+
+	if (!(spa_mode_global & FWRITE))
+		return (EROFS);
+
+	txg = spa_vdev_enter(spa);
+
+	if (spa->spa_root_vdev->vdev_state != VDEV_STATE_HEALTHY)
+		return (spa_vdev_exit(spa, NULL, txg, ENXIO));
+
+	oldguid = spa_guid(spa);
+	newguid = spa_generate_guid(NULL);
+	ASSERT3U(oldguid, !=, newguid);
+
+	spa->spa_root_vdev->vdev_guid = newguid;
+	spa->spa_root_vdev->vdev_guid_sum += (newguid - oldguid);
+
+	vdev_config_dirty(spa->spa_root_vdev);
+
+	spa_event_notify(spa, NULL, ESC_ZFS_POOL_REGUID);
+
+	return (spa_vdev_exit(spa, NULL, txg, 0));
+}
+
+/*
  * ==========================================================================
  * SPA state manipulation (open/create/destroy/import/export)
  * ==========================================================================
@@ -1025,6 +1088,11 @@ spa_unload(spa_t *spa)
 
 	spa->spa_async_suspended = 0;
 
+	if (spa->spa_comment != NULL) {
+		spa_strfree(spa->spa_comment);
+		spa->spa_comment = NULL;
+	}
+
 	spa_config_exit(spa, SCL_ALL, FTAG);
 }
 
@@ -1742,6 +1810,7 @@ spa_load(spa_t *spa, spa_load_state_t state, spa_import_type_t type,
 {
 	nvlist_t *config = spa->spa_config;
 	char *ereport = FM_EREPORT_ZFS_POOL;
+	char *comment;
 	int error;
 	uint64_t pool_guid;
 	nvlist_t *nvl;
@@ -1749,6 +1818,10 @@ spa_load(spa_t *spa, spa_load_state_t state, spa_import_type_t type,
 	if (nvlist_lookup_uint64(config, ZPOOL_CONFIG_POOL_GUID, &pool_guid))
 		return (EINVAL);
 
+	ASSERT(spa->spa_comment == NULL);
+	if (nvlist_lookup_string(config, ZPOOL_CONFIG_COMMENT, &comment) == 0)
+		spa->spa_comment = spa_strdup(comment);
+
 	/*
 	 * Versioning wasn't explicitly added to the label until later, so if
 	 * it's not present treat it as the initial version.
@@ -1764,7 +1837,7 @@ spa_load(spa_t *spa, spa_load_state_t state, spa_import_type_t type,
 	    spa_guid_exists(pool_guid, 0)) {
 		error = EEXIST;
 	} else {
-		spa->spa_load_guid = pool_guid;
+		spa->spa_config_guid = pool_guid;
 
 		if (nvlist_lookup_nvlist(config, ZPOOL_CONFIG_SPLIT,
 		    &nvl) == 0) {
@@ -5380,6 +5453,20 @@ spa_sync_props(void *arg1, void *arg2, dmu_tx_t *tx)
 			 * properties.
 			 */
 			break;
+		case ZPOOL_PROP_COMMENT:
+			VERIFY(nvpair_value_string(elem, &strval) == 0);
+			if (spa->spa_comment != NULL)
+				spa_strfree(spa->spa_comment);
+			spa->spa_comment = spa_strdup(strval);
+			/*
+			 * We need to dirty the configuration on all the vdevs
+			 * so that their labels get updated.  It's unnecessary
+			 * to do this for pool creation since the vdev's
+			 * configuratoin has already been dirtied.
+			 */
+			if (tx->tx_txg != TXG_INITIAL)
+				vdev_config_dirty(spa->spa_root_vdev);
+			break;
 		default:
 			/*
 			 * Set pool property values in the poolprops mos object.
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa_config.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa_config.c
index 0b8255e..a072233 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa_config.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa_config.c
@@ -21,6 +21,8 @@
 
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright 2011 Nexenta Systems, Inc. All rights reserved.
+ * Copyright (c) 2011 by Delphix. All rights reserved.
  */
 
 #include <sys/zfs_context.h>
@@ -343,6 +345,10 @@ spa_config_generate(spa_t *spa, vdev_t *vd, uint64_t txg, int getstats)
 	    txg) == 0);
 	VERIFY(nvlist_add_uint64(config, ZPOOL_CONFIG_POOL_GUID,
 	    spa_guid(spa)) == 0);
+	VERIFY(spa->spa_comment == NULL || nvlist_add_string(config,
+	    ZPOOL_CONFIG_COMMENT, spa->spa_comment) == 0);
+
+
 #ifdef	_KERNEL
 	hostid = zone_get_hostid(NULL);
 #else	/* _KERNEL */
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa_history.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa_history.c
index 130c918..a853de7 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa_history.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa_history.c
@@ -21,6 +21,7 @@
 
 /*
  * Copyright (c) 2006, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2011 by Delphix. All rights reserved.
  */
 
 #include <sys/spa.h>
@@ -101,11 +102,11 @@ spa_history_create_obj(spa_t *spa, dmu_tx_t *tx)
 
 	/*
 	 * Figure out maximum size of history log.  We set it at
-	 * 1% of pool size, with a max of 32MB and min of 128KB.
+	 * 0.1% of pool size, with a max of 1G and min of 128KB.
 	 */
 	shpp->sh_phys_max_off =
-	    metaslab_class_get_dspace(spa_normal_class(spa)) / 100;
-	shpp->sh_phys_max_off = MIN(shpp->sh_phys_max_off, 32<<20);
+	    metaslab_class_get_dspace(spa_normal_class(spa)) / 1000;
+	shpp->sh_phys_max_off = MIN(shpp->sh_phys_max_off, 1<<30);
 	shpp->sh_phys_max_off = MAX(shpp->sh_phys_max_off, 128<<10);
 
 	dmu_buf_rele(dbp, FTAG);
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa_misc.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa_misc.c
index 9138309..6342452 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa_misc.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa_misc.c
@@ -21,6 +21,7 @@
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2011 by Delphix. All rights reserved.
+ * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
  */
 
 #include <sys/zfs_context.h>
@@ -1308,13 +1309,24 @@ spa_guid(spa_t *spa)
 	/*
 	 * If we fail to parse the config during spa_load(), we can go through
 	 * the error path (which posts an ereport) and end up here with no root
-	 * vdev.  We stash the original pool guid in 'spa_load_guid' to handle
+	 * vdev.  We stash the original pool guid in 'spa_config_guid' to handle
 	 * this case.
 	 */
 	if (spa->spa_root_vdev != NULL)
 		return (spa->spa_root_vdev->vdev_guid);
 	else
-		return (spa->spa_load_guid);
+		return (spa->spa_config_guid);
+}
+
+uint64_t
+spa_load_guid(spa_t *spa)
+{
+	/*
+	 * This is a GUID that exists solely as a reference for the
+	 * purposes of the arc.  It is generated at load time, and
+	 * is never written to persistent storage.
+	 */
+	return (spa->spa_load_guid);
 }
 
 uint64_t
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/dmu.h b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/dmu.h
index 50a2f84..585acf3 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/dmu.h
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/dmu.h
@@ -20,6 +20,7 @@
  */
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2011 by Delphix. All rights reserved.
  */
 /*
  * Copyright 2011 Nexenta Systems, Inc. All rights reserved.
@@ -194,7 +195,9 @@ int dmu_objset_create(const char *name, dmu_objset_type_t type, uint64_t flags,
 int dmu_objset_clone(const char *name, struct dsl_dataset *clone_origin,
     uint64_t flags);
 int dmu_objset_destroy(const char *name, boolean_t defer);
-int dmu_snapshots_destroy(char *fsname, char *snapname, boolean_t defer);
+int dmu_get_recursive_snaps_nvl(const char *fsname, const char *snapname,
+    struct nvlist *snaps);
+int dmu_snapshots_destroy_nvl(struct nvlist *snaps, boolean_t defer, char *);
 int dmu_objset_snapshot(char *fsname, char *snapname, char *tag,
     struct nvlist *props, boolean_t recursive, boolean_t temporary, int fd);
 int dmu_objset_rename(const char *name, const char *newname,
@@ -705,6 +708,8 @@ void dmu_traverse_objset(objset_t *os, uint64_t txg_start,
 
 int dmu_sendbackup(objset_t *tosnap, objset_t *fromsnap, boolean_t fromorigin,
     struct file *fp, offset_t *off);
+int dmu_send_estimate(objset_t *tosnap, objset_t *fromsnap,
+    boolean_t fromorigin, uint64_t *sizep);
 
 typedef struct dmu_recv_cookie {
 	/*
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/dsl_dataset.h b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/dsl_dataset.h
index e4b8127..50b2e7b 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/dsl_dataset.h
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/dsl_dataset.h
@@ -22,6 +22,7 @@
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2011 Pawel Jakub Dawidek <pawel@dawidek.net>.
  * All rights reserved.
+ * Copyright (c) 2011 by Delphix. All rights reserved.
  */
 
 #ifndef	_SYS_DSL_DATASET_H
@@ -257,6 +258,10 @@ void dsl_dataset_space(dsl_dataset_t *ds,
     uint64_t *refdbytesp, uint64_t *availbytesp,
     uint64_t *usedobjsp, uint64_t *availobjsp);
 uint64_t dsl_dataset_fsid_guid(dsl_dataset_t *ds);
+int dsl_dataset_space_written(dsl_dataset_t *oldsnap, dsl_dataset_t *new,
+    uint64_t *usedp, uint64_t *compp, uint64_t *uncompp);
+int dsl_dataset_space_wouldfree(dsl_dataset_t *firstsnap, dsl_dataset_t *last,
+    uint64_t *usedp, uint64_t *compp, uint64_t *uncompp);
 
 int dsl_dsobj_to_dsname(char *pname, uint64_t obj, char *buf);
 
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/dsl_deleg.h b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/dsl_deleg.h
index 73c43bd..9db6d07 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/dsl_deleg.h
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/dsl_deleg.h
@@ -20,6 +20,7 @@
  */
 /*
  * Copyright (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2011 by Delphix. All rights reserved.
  */
 
 #ifndef	_SYS_DSL_DELEG_H
@@ -64,7 +65,8 @@ extern "C" {
 int dsl_deleg_get(const char *ddname, nvlist_t **nvp);
 int dsl_deleg_set(const char *ddname, nvlist_t *nvp, boolean_t unset);
 int dsl_deleg_access(const char *ddname, const char *perm, cred_t *cr);
-int dsl_deleg_access_impl(struct dsl_dataset *ds, const char *perm, cred_t *cr);
+int dsl_deleg_access_impl(struct dsl_dataset *ds, boolean_t descendent,
+    const char *perm, cred_t *cr);
 void dsl_deleg_set_create_perms(dsl_dir_t *dd, dmu_tx_t *tx, cred_t *cr);
 int dsl_deleg_can_allow(char *ddname, nvlist_t *nvp, cred_t *cr);
 int dsl_deleg_can_unallow(char *ddname, nvlist_t *nvp, cred_t *cr);
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/spa.h b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/spa.h
index fe6e727..a2a76e3 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/spa.h
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/spa.h
@@ -21,6 +21,7 @@
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2011 by Delphix. All rights reserved.
+ * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
  */
 
 #ifndef _SYS_SPA_H
@@ -578,6 +579,7 @@ extern void spa_altroot(spa_t *, char *, size_t);
 extern int spa_sync_pass(spa_t *spa);
 extern char *spa_name(spa_t *spa);
 extern uint64_t spa_guid(spa_t *spa);
+extern uint64_t spa_load_guid(spa_t *spa);
 extern uint64_t spa_last_synced_txg(spa_t *spa);
 extern uint64_t spa_first_txg(spa_t *spa);
 extern uint64_t spa_syncing_txg(spa_t *spa);
@@ -611,6 +613,7 @@ extern uint64_t spa_get_random(uint64_t range);
 extern uint64_t spa_generate_guid(spa_t *spa);
 extern void sprintf_blkptr(char *buf, const blkptr_t *bp);
 extern void spa_freeze(spa_t *spa);
+extern int spa_change_guid(spa_t *spa);
 extern void spa_upgrade(spa_t *spa, uint64_t version);
 extern void spa_evict_all(void);
 extern vdev_t *spa_lookup_by_guid(spa_t *spa, uint64_t guid,
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/spa_impl.h b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/spa_impl.h
index 2dbe552..88d1477 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/spa_impl.h
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/spa_impl.h
@@ -21,6 +21,7 @@
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2011 by Delphix. All rights reserved.
+ * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
  */
 
 #ifndef _SYS_SPA_IMPL_H
@@ -111,6 +112,7 @@ struct spa {
 	 * Fields protected by spa_namespace_lock.
 	 */
 	char		spa_name[MAXNAMELEN];	/* pool name */
+	char		*spa_comment;		/* comment */
 	avl_node_t	spa_avl;		/* node in spa_namespace_avl */
 	nvlist_t	*spa_config;		/* last synced config */
 	nvlist_t	*spa_config_syncing;	/* currently syncing config */
@@ -136,7 +138,8 @@ struct spa {
 	objset_t	*spa_meta_objset;	/* copy of dp->dp_meta_objset */
 	txg_list_t	spa_vdev_txg_list;	/* per-txg dirty vdev list */
 	vdev_t		*spa_root_vdev;		/* top-level vdev container */
-	uint64_t	spa_load_guid;		/* initial guid for spa_load */
+	uint64_t	spa_config_guid;	/* config pool guid */
+	uint64_t	spa_load_guid;		/* spa_load initialized guid */
 	list_t		spa_config_dirty_list;	/* vdevs with dirty config */
 	list_t		spa_state_dirty_list;	/* vdevs with dirty state */
 	spa_aux_vdev_t	spa_spares;		/* hot spares */
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/vdev.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/vdev.c
index 51a3c79..04597ec 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/vdev.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/vdev.c
@@ -21,6 +21,8 @@
 
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
+ * Copyright (c) 2011 by Delphix. All rights reserved.
  */
 
 #include <sys/zfs_context.h>
@@ -297,6 +299,7 @@ vdev_alloc_common(spa_t *spa, uint_t id, uint64_t guid, vdev_ops_t *ops)
 	if (spa->spa_root_vdev == NULL) {
 		ASSERT(ops == &vdev_root_ops);
 		spa->spa_root_vdev = vd;
+		spa->spa_load_guid = spa_generate_guid(NULL);
 	}
 
 	if (guid == 0 && ops != &vdev_hole_ops) {
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zap_micro.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zap_micro.c
index b403097..6e506a4 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zap_micro.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zap_micro.c
@@ -20,6 +20,7 @@
  */
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2011 by Delphix. All rights reserved.
  */
 
 #include <sys/zio.h>
@@ -1414,7 +1415,7 @@ zap_count_write(objset_t *os, uint64_t zapobj, const char *name, int add,
 	}
 
 	/*
-	 * We lock the zap with adding ==  FALSE. Because, if we pass
+	 * We lock the zap with adding == FALSE. Because, if we pass
 	 * the actual value of add, it could trigger a mzap_upgrade().
 	 * At present we are just evaluating the possibility of this operation
 	 * and hence we donot want to trigger an upgrade.
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_ioctl.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_ioctl.c
index 37309c1..882bf02e 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_ioctl.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_ioctl.c
@@ -23,6 +23,8 @@
  * Copyright (c) 2011 Pawel Jakub Dawidek <pawel@dawidek.net>.
  * All rights reserved.
  * Portions Copyright 2011 Martin Matuska <mm@FreeBSD.org>
+ * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
+ * Copyright (c) 2011 by Delphix. All rights reserved.
  */
 
 #include <sys/types.h>
@@ -348,17 +350,37 @@ zfs_dozonecheck_ds(const char *dataset, dsl_dataset_t *ds, cred_t *cr)
 	return (zfs_dozonecheck_impl(dataset, zoned, cr));
 }
 
+/*
+ * If name ends in a '@', then require recursive permissions.
+ */
 int
 zfs_secpolicy_write_perms(const char *name, const char *perm, cred_t *cr)
 {
 	int error;
+	boolean_t descendent = B_FALSE;
+	dsl_dataset_t *ds;
+	char *at;
+
+	at = strchr(name, '@');
+	if (at != NULL && at[1] == '\0') {
+		*at = '\0';
+		descendent = B_TRUE;
+	}
+
+	error = dsl_dataset_hold(name, FTAG, &ds);
+	if (at != NULL)
+		*at = '@';
+	if (error != 0)
+		return (error);
 
-	error = zfs_dozonecheck(name, cr);
+	error = zfs_dozonecheck_ds(name, ds, cr);
 	if (error == 0) {
 		error = secpolicy_zfs(cr);
 		if (error)
-			error = dsl_deleg_access(name, perm, cr);
+			error = dsl_deleg_access_impl(ds, descendent, perm, cr);
 	}
+
+	dsl_dataset_rele(ds, FTAG);
 	return (error);
 }
 
@@ -372,7 +394,7 @@ zfs_secpolicy_write_perms_ds(const char *name, dsl_dataset_t *ds,
 	if (error == 0) {
 		error = secpolicy_zfs(cr);
 		if (error)
-			error = dsl_deleg_access_impl(ds, perm, cr);
+			error = dsl_deleg_access_impl(ds, B_FALSE, perm, cr);
 	}
 	return (error);
 }
@@ -685,24 +707,14 @@ zfs_secpolicy_destroy(zfs_cmd_t *zc, cred_t *cr)
 /*
  * Destroying snapshots with delegated permissions requires
  * descendent mount and destroy permissions.
- * Reassemble the full filesystem@snap name so dsl_deleg_access()
- * can do the correct permission check.
- *
- * Since this routine is used when doing a recursive destroy of snapshots
- * and destroying snapshots requires descendent permissions, a successfull
- * check of the top level snapshot applies to snapshots of all descendent
- * datasets as well.
- *
- * The top level snapshot may not exist when doing a recursive destroy.
- * In this case fallback to permissions of the parent dataset.
  */
 static int
-zfs_secpolicy_destroy_snaps(zfs_cmd_t *zc, cred_t *cr)
+zfs_secpolicy_destroy_recursive(zfs_cmd_t *zc, cred_t *cr)
 {
 	int error;
 	char *dsname;
 
-	dsname = kmem_asprintf("%s@%s", zc->zc_name, zc->zc_value);
+	dsname = kmem_asprintf("%s@", zc->zc_name);
 
 	error = zfs_secpolicy_destroy_perms(dsname, cr);
 
@@ -1469,6 +1481,20 @@ zfs_ioc_pool_get_history(zfs_cmd_t *zc)
 }
 
 static int
+zfs_ioc_pool_reguid(zfs_cmd_t *zc)
+{
+	spa_t *spa;
+	int error;
+
+	error = spa_open(zc->zc_name, &spa, FTAG);
+	if (error == 0) {
+		error = spa_change_guid(spa);
+		spa_close(spa, FTAG);
+	}
+	return (error);
+}
+
+static int
 zfs_ioc_dsobj_to_dsname(zfs_cmd_t *zc)
 {
 	int error;
@@ -1765,9 +1791,12 @@ zfs_ioc_objset_stats_impl(zfs_cmd_t *zc, objset_t *os)
 		 * inconsistent.  So this is a bit of a workaround...
 		 * XXX reading with out owning
 		 */
-		if (!zc->zc_objset_stats.dds_inconsistent) {
-			if (dmu_objset_type(os) == DMU_OST_ZVOL)
-				VERIFY(zvol_get_stats(os, nv) == 0);
+		if (!zc->zc_objset_stats.dds_inconsistent &&
+		    dmu_objset_type(os) == DMU_OST_ZVOL) {
+			error = zvol_get_stats(os, nv);
+			if (error == EIO)
+				return (error);
+			VERIFY3S(error, ==, 0);
 		}
 		error = put_nvlist(zc, nv);
 		nvlist_free(nv);
@@ -1978,8 +2007,7 @@ top:
 		    NULL, &zc->zc_cookie);
 		if (error == ENOENT)
 			error = ESRCH;
-	} while (error == 0 && dataset_name_hidden(zc->zc_name) &&
-	    !(zc->zc_iflags & FKIOCTL));
+	} while (error == 0 && dataset_name_hidden(zc->zc_name));
 	dmu_objset_rele(os, FTAG);
 
 	/*
@@ -2257,6 +2285,8 @@ retry:
 				if (nvpair_type(propval) !=
 				    DATA_TYPE_UINT64_ARRAY)
 					err = EINVAL;
+			} else {
+				err = EINVAL;
 			}
 		} else if (err == 0) {
 			if (nvpair_type(propval) == DATA_TYPE_STRING) {
@@ -3124,25 +3154,62 @@ zfs_unmount_snap(const char *name, void *arg)
 
 /*
  * inputs:
- * zc_name		name of filesystem
- * zc_value		short name of snapshot
+ * zc_name		name of filesystem, snaps must be under it
+ * zc_nvlist_src[_size]	full names of snapshots to destroy
  * zc_defer_destroy	mark for deferred destroy
  *
- * outputs:	none
+ * outputs:
+ * zc_name		on failure, name of failed snapshot
  */
 static int
-zfs_ioc_destroy_snaps(zfs_cmd_t *zc)
+zfs_ioc_destroy_snaps_nvl(zfs_cmd_t *zc)
 {
-	int err;
+	int err, len;
+	nvlist_t *nvl;
+	nvpair_t *pair;
 
-	if (snapshot_namecheck(zc->zc_value, NULL, NULL) != 0)
-		return (EINVAL);
-	err = dmu_objset_find(zc->zc_name,
-	    zfs_unmount_snap, zc->zc_value, DS_FIND_CHILDREN);
-	if (err)
+	if ((err = get_nvlist(zc->zc_nvlist_src, zc->zc_nvlist_src_size,
+	    zc->zc_iflags, &nvl)) != 0) {
+#ifndef __FreeBSD__
 		return (err);
-	return (dmu_snapshots_destroy(zc->zc_name, zc->zc_value,
-	    zc->zc_defer_destroy));
+#else
+		/*
+		 * We are probably called by older binaries,
+		 * allocate and populate nvlist with recursive snapshots
+		 */
+		if (snapshot_namecheck(zc->zc_value, NULL, NULL) != 0)
+			return (EINVAL);
+		VERIFY(nvlist_alloc(&nvl, NV_UNIQUE_NAME, KM_SLEEP) == 0);
+		err = dmu_get_recursive_snaps_nvl(zc->zc_name,
+		    zc->zc_value, nvl);
+		if (err) {
+			nvlist_free(nvl);
+			return (err);
+		}
+#endif /* __FreeBSD__ */
+	}
+
+	len = strlen(zc->zc_name);
+	for (pair = nvlist_next_nvpair(nvl, NULL); pair != NULL;
+	    pair = nvlist_next_nvpair(nvl, pair)) {
+		const char *name = nvpair_name(pair);
+		/*
+		 * The snap name must be underneath the zc_name.  This ensures
+		 * that our permission checks were legitimate.
+		 */
+		if (strncmp(zc->zc_name, name, len) != 0 ||
+		    (name[len] != '@' && name[len] != '/')) {
+			nvlist_free(nvl);
+			return (EINVAL);
+		}
+
+		(void) zfs_unmount_snap(name, NULL);
+	}
+
+	err = dmu_snapshots_destroy_nvl(nvl, zc->zc_defer_destroy,
+	    zc->zc_name);
+	nvlist_free(nvl);
+	return (err);
 }
 
 /*
@@ -3789,6 +3856,8 @@ out:
  * zc_obj	fromorigin flag (mutually exclusive with zc_fromobj)
  * zc_sendobj	objsetid of snapshot to send
  * zc_fromobj	objsetid of incremental fromsnap (may be zero)
+ * zc_guid	if set, estimate size of stream only.  zc_cookie is ignored.
+ *		output size in zc_objset_type.
  *
  * outputs: none
  */
@@ -3797,13 +3866,13 @@ zfs_ioc_send(zfs_cmd_t *zc)
 {
 	objset_t *fromsnap = NULL;
 	objset_t *tosnap;
-	file_t *fp;
 	int error;
 	offset_t off;
 	dsl_dataset_t *ds;
 	dsl_dataset_t *dsfrom = NULL;
 	spa_t *spa;
 	dsl_pool_t *dp;
+	boolean_t estimate = (zc->zc_guid != 0);
 
 	error = spa_open(zc->zc_name, &spa, FTAG);
 	if (error)
@@ -3844,20 +3913,25 @@ zfs_ioc_send(zfs_cmd_t *zc)
 		spa_close(spa, FTAG);
 	}
 
-	fp = getf(zc->zc_cookie);
-	if (fp == NULL) {
-		dsl_dataset_rele(ds, FTAG);
-		if (dsfrom)
-			dsl_dataset_rele(dsfrom, FTAG);
-		return (EBADF);
-	}
+	if (estimate) {
+		error = dmu_send_estimate(tosnap, fromsnap, zc->zc_obj,
+		    &zc->zc_objset_type);
+	} else {
+		file_t *fp = getf(zc->zc_cookie);
+		if (fp == NULL) {
+			dsl_dataset_rele(ds, FTAG);
+			if (dsfrom)
+				dsl_dataset_rele(dsfrom, FTAG);
+			return (EBADF);
+		}
 
-	off = fp->f_offset;
-	error = dmu_sendbackup(tosnap, fromsnap, zc->zc_obj, fp, &off);
+		off = fp->f_offset;
+		error = dmu_sendbackup(tosnap, fromsnap, zc->zc_obj, fp, &off);
 
-	if (off >= 0 && off <= MAXOFFSET_T)
-		fp->f_offset = off;
-	releasef(zc->zc_cookie);
+		if (off >= 0 && off <= MAXOFFSET_T)
+			fp->f_offset = off;
+		releasef(zc->zc_cookie);
+	}
 	if (dsfrom)
 		dsl_dataset_rele(dsfrom, FTAG);
 	dsl_dataset_rele(ds, FTAG);
@@ -4666,6 +4740,70 @@ zfs_ioc_get_holds(zfs_cmd_t *zc)
 }
 
 /*
+ * inputs:
+ * zc_name		name of new filesystem or snapshot
+ * zc_value		full name of old snapshot
+ *
+ * outputs:
+ * zc_cookie		space in bytes
+ * zc_objset_type	compressed space in bytes
+ * zc_perm_action	uncompressed space in bytes
+ */
+static int
+zfs_ioc_space_written(zfs_cmd_t *zc)
+{
+	int error;
+	dsl_dataset_t *new, *old;
+
+	error = dsl_dataset_hold(zc->zc_name, FTAG, &new);
+	if (error != 0)
+		return (error);
+	error = dsl_dataset_hold(zc->zc_value, FTAG, &old);
+	if (error != 0) {
+		dsl_dataset_rele(new, FTAG);
+		return (error);
+	}
+
+	error = dsl_dataset_space_written(old, new, &zc->zc_cookie,
+	    &zc->zc_objset_type, &zc->zc_perm_action);
+	dsl_dataset_rele(old, FTAG);
+	dsl_dataset_rele(new, FTAG);
+	return (error);
+}
+
+/*
+ * inputs:
+ * zc_name		full name of last snapshot
+ * zc_value		full name of first snapshot
+ *
+ * outputs:
+ * zc_cookie		space in bytes
+ * zc_objset_type	compressed space in bytes
+ * zc_perm_action	uncompressed space in bytes
+ */
+static int
+zfs_ioc_space_snaps(zfs_cmd_t *zc)
+{
+	int error;
+	dsl_dataset_t *new, *old;
+
+	error = dsl_dataset_hold(zc->zc_name, FTAG, &new);
+	if (error != 0)
+		return (error);
+	error = dsl_dataset_hold(zc->zc_value, FTAG, &old);
+	if (error != 0) {
+		dsl_dataset_rele(new, FTAG);
+		return (error);
+	}
+
+	error = dsl_dataset_space_wouldfree(old, new, &zc->zc_cookie,
+	    &zc->zc_objset_type, &zc->zc_perm_action);
+	dsl_dataset_rele(old, FTAG);
+	dsl_dataset_rele(new, FTAG);
+	return (error);
+}
+
+/*
  * pool create, destroy, and export don't log the history as part of
  * zfsdev_ioctl, but rather zfs_ioc_pool_create, and zfs_ioc_pool_export
  * do the logging of those commands.
@@ -4739,7 +4877,7 @@ static zfs_ioc_vec_t zfs_ioc_vec[] = {
 	    B_TRUE },
 	{ zfs_ioc_rename, zfs_secpolicy_rename,	DATASET_NAME, B_TRUE, B_TRUE },
 	{ zfs_ioc_recv, zfs_secpolicy_receive, DATASET_NAME, B_TRUE, B_TRUE },
-	{ zfs_ioc_send, zfs_secpolicy_send, DATASET_NAME, B_TRUE, B_FALSE },
+	{ zfs_ioc_send, zfs_secpolicy_send, DATASET_NAME, B_FALSE, B_FALSE },
 	{ zfs_ioc_inject_fault,	zfs_secpolicy_inject, NO_NAME, B_FALSE,
 	    B_FALSE },
 	{ zfs_ioc_clear_fault, zfs_secpolicy_inject, NO_NAME, B_FALSE,
@@ -4751,7 +4889,7 @@ static zfs_ioc_vec_t zfs_ioc_vec[] = {
 	{ zfs_ioc_clear, zfs_secpolicy_config, POOL_NAME, B_TRUE, B_FALSE },
 	{ zfs_ioc_promote, zfs_secpolicy_promote, DATASET_NAME, B_TRUE,
 	    B_TRUE },
-	{ zfs_ioc_destroy_snaps, zfs_secpolicy_destroy_snaps, DATASET_NAME,
+	{ zfs_ioc_destroy_snaps_nvl, zfs_secpolicy_destroy_recursive, DATASET_NAME,
 	    B_TRUE, B_TRUE },
 	{ zfs_ioc_snapshot, zfs_secpolicy_snapshot, DATASET_NAME, B_TRUE,
 	    B_TRUE },
@@ -4795,7 +4933,13 @@ static zfs_ioc_vec_t zfs_ioc_vec[] = {
 	{ zfs_ioc_obj_to_stats, zfs_secpolicy_diff, DATASET_NAME, B_FALSE,
 	    B_TRUE },
 	{ zfs_ioc_jail, zfs_secpolicy_config, DATASET_NAME, B_TRUE, B_FALSE },
-	{ zfs_ioc_unjail, zfs_secpolicy_config, DATASET_NAME, B_TRUE, B_FALSE }
+	{ zfs_ioc_unjail, zfs_secpolicy_config, DATASET_NAME, B_TRUE, B_FALSE },
+	{ zfs_ioc_pool_reguid, zfs_secpolicy_config, POOL_NAME, B_TRUE,
+	    B_TRUE },
+	{ zfs_ioc_space_written, zfs_secpolicy_read, DATASET_NAME, B_FALSE,
+	    B_TRUE },
+	{ zfs_ioc_space_snaps, zfs_secpolicy_read, DATASET_NAME, B_FALSE,
+	    B_TRUE }
 };
 
 int
diff --git a/sys/cddl/contrib/opensolaris/uts/common/sys/fs/zfs.h b/sys/cddl/contrib/opensolaris/uts/common/sys/fs/zfs.h
index c5ed728..0729bff 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/sys/fs/zfs.h
+++ b/sys/cddl/contrib/opensolaris/uts/common/sys/fs/zfs.h
@@ -22,6 +22,7 @@
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2011 by Delphix. All rights reserved.
+ * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
  */
 
 /* Portions Copyright 2010 Robert Milkowski */
@@ -126,6 +127,8 @@ typedef enum {
 	ZFS_PROP_MLSLABEL,
 	ZFS_PROP_SYNC,
 	ZFS_PROP_REFRATIO,
+	ZFS_PROP_WRITTEN,
+	ZFS_PROP_CLONES,
 	ZFS_NUM_PROPS
 } zfs_prop_t;
 
@@ -165,9 +168,13 @@ typedef enum {
 	ZPOOL_PROP_FREE,
 	ZPOOL_PROP_ALLOCATED,
 	ZPOOL_PROP_READONLY,
+	ZPOOL_PROP_COMMENT,
 	ZPOOL_NUM_PROPS
 } zpool_prop_t;
 
+/* Small enough to not hog a whole line of printout in zpool(1M). */
+#define	ZPROP_MAX_COMMENT	32
+
 #define	ZPROP_CONT		-2
 #define	ZPROP_INVAL		-1
 
@@ -492,6 +499,7 @@ typedef struct zpool_rewind_policy {
 #define	ZPOOL_CONFIG_SPLIT_LIST		"guid_list"
 #define	ZPOOL_CONFIG_REMOVING		"removing"
 #define	ZPOOL_CONFIG_RESILVERING	"resilvering"
+#define	ZPOOL_CONFIG_COMMENT		"comment"
 #define	ZPOOL_CONFIG_SUSPENDED		"suspended"	/* not stored on disk */
 #define	ZPOOL_CONFIG_TIMESTAMP		"timestamp"	/* not stored on disk */
 #define	ZPOOL_CONFIG_BOOTFS		"bootfs"	/* not stored on disk */
@@ -758,7 +766,7 @@ typedef	unsigned long	zfs_ioc_t;
 #define	ZFS_IOC_ERROR_LOG		_IOWR('Z', 32, struct zfs_cmd)
 #define	ZFS_IOC_CLEAR			_IOWR('Z', 33, struct zfs_cmd)
 #define	ZFS_IOC_PROMOTE			_IOWR('Z', 34, struct zfs_cmd)
-#define	ZFS_IOC_DESTROY_SNAPS		_IOWR('Z', 35, struct zfs_cmd)
+#define	ZFS_IOC_DESTROY_SNAPS_NVL	_IOWR('Z', 35, struct zfs_cmd)
 #define	ZFS_IOC_SNAPSHOT		_IOWR('Z', 36, struct zfs_cmd)
 #define	ZFS_IOC_DSOBJ_TO_DSNAME		_IOWR('Z', 37, struct zfs_cmd)
 #define	ZFS_IOC_OBJ_TO_PATH		_IOWR('Z', 38, struct zfs_cmd)
@@ -783,6 +791,9 @@ typedef	unsigned long	zfs_ioc_t;
 #define	ZFS_IOC_OBJ_TO_STATS		_IOWR('Z', 57, struct zfs_cmd)
 #define	ZFS_IOC_JAIL			_IOWR('Z', 58, struct zfs_cmd)
 #define	ZFS_IOC_UNJAIL			_IOWR('Z', 59, struct zfs_cmd)
+#define	ZFS_IOC_POOL_REGUID		_IOWR('Z', 60, struct zfs_cmd)
+#define	ZFS_IOC_SPACE_WRITTEN		_IOWR('Z', 61, struct zfs_cmd)
+#define	ZFS_IOC_SPACE_SNAPS		_IOWR('Z', 62, struct zfs_cmd)
 
 /*
  * Internal SPA load state.  Used by FMA diagnosis engine.
@@ -844,6 +855,7 @@ typedef enum {
  *	ESC_ZFS_RESILVER_START
  *	ESC_ZFS_RESILVER_END
  *	ESC_ZFS_POOL_DESTROY
+ *	ESC_ZFS_POOL_REGUID
  *
  *		ZFS_EV_POOL_NAME	DATA_TYPE_STRING
  *		ZFS_EV_POOL_GUID	DATA_TYPE_UINT64
diff --git a/sys/cddl/contrib/opensolaris/uts/common/sys/sysevent/eventdefs.h b/sys/cddl/contrib/opensolaris/uts/common/sys/sysevent/eventdefs.h
index dfa7817..89bb06e 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/sys/sysevent/eventdefs.h
+++ b/sys/cddl/contrib/opensolaris/uts/common/sys/sysevent/eventdefs.h
@@ -20,6 +20,7 @@
  */
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
  */
 
 #ifndef	_SYS_SYSEVENT_EVENTDEFS_H
@@ -256,6 +257,7 @@ extern "C" {
 #define	ESC_ZFS_SCRUB_FINISH		"ESC_ZFS_scrub_finish"
 #define	ESC_ZFS_VDEV_SPARE		"ESC_ZFS_vdev_spare"
 #define	ESC_ZFS_BOOTFS_VDEV_ATTACH	"ESC_ZFS_bootfs_vdev_attach"
+#define	ESC_ZFS_POOL_REGUID		"ESC_ZFS_pool_reguid"
 #define	ESC_ZFS_VDEV_AUTOEXPAND		"ESC_ZFS_vdev_autoexpand"
 
 /*