1748 desire support for reguid in zfs

Reviewed by: George Wilson <gwilson@zfsmail.com>
Reviewed by: Igor Kozhukhov <ikozhukhov@gmail.com>
Reviewed by: Alexander Eremin <alexander.eremin@nexenta.com>
Reviewed by: Alexander Stetsenko <ams@nexenta.com>
Approved by: Richard Lowe <richlowe@richlowe.net>

16 files changed, 234 insertions, 17 deletions

diff --git a/usr/src/cmd/truss/codes.c b/usr/src/cmd/truss/codes.c
index 119dba0aac..2a7af6f311 100644
--- a/usr/src/cmd/truss/codes.c
+++ b/usr/src/cmd/truss/codes.c
@@ -21,6 +21,8 @@
 
 /*
  * Copyright (c) 1989, 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) 1984, 1986, 1987, 1988, 1989 AT&T	*/
@@ -1248,6 +1250,8 @@ const struct ioc {
 		"zfs_cmd_t" },
 	{ (uint_t)ZFS_IOC_OBJ_TO_STATS,		"ZFS_IOC_OBJ_TO_STATS",
 		"zfs_cmd_t" },
+	{ (uint_t)ZFS_IOC_POOL_REGUID,		"ZFS_IOC_POOL_REGUID",
+		"zfs_cmd_t" },
 
 	/* kssl ioctls */
 	{ (uint_t)KSSL_ADD_ENTRY,		"KSSL_ADD_ENTRY",
diff --git a/usr/src/cmd/zpool/zpool_main.c b/usr/src/cmd/zpool/zpool_main.c
index 1cb2e63d1f..b5837e5572 100644
--- a/usr/src/cmd/zpool/zpool_main.c
+++ b/usr/src/cmd/zpool/zpool_main.c
@@ -22,6 +22,7 @@
 /*
  * 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 <assert.h>
@@ -65,6 +66,8 @@ static int zpool_do_online(int, char **);
 static int zpool_do_offline(int, char **);
 static int zpool_do_clear(int, char **);
 
+static int zpool_do_reguid(int, char **);
+
 static int zpool_do_attach(int, char **);
 static int zpool_do_detach(int, char **);
 static int zpool_do_replace(int, char **);
@@ -122,7 +125,8 @@ typedef enum {
 	HELP_UPGRADE,
 	HELP_GET,
 	HELP_SET,
-	HELP_SPLIT
+	HELP_SPLIT,
+	HELP_REGUID
 } zpool_help_t;
 
 
@@ -166,6 +170,7 @@ static zpool_command_t command_table[] = {
 	{ "import",	zpool_do_import,	HELP_IMPORT		},
 	{ "export",	zpool_do_export,	HELP_EXPORT		},
 	{ "upgrade",	zpool_do_upgrade,	HELP_UPGRADE		},
+	{ "reguid",	zpool_do_reguid,	HELP_REGUID		},
 	{ NULL },
 	{ "history",	zpool_do_history,	HELP_HISTORY		},
 	{ "get",	zpool_do_get,		HELP_GET		},
@@ -244,6 +249,8 @@ get_usage(zpool_help_t idx) {
 		return (gettext("\tsplit [-n] [-R altroot] [-o mntopts]\n"
 		    "\t    [-o property=value] <pool> <newpool> "
 		    "[<device> ...]\n"));
+	case HELP_REGUID:
+		return (gettext("\treguid <pool>\n"));
 	}
 
 	abort();
@@ -3193,6 +3200,52 @@ zpool_do_clear(int argc, char **argv)
 	return (ret);
 }
 
+/*
+ * zpool reguid <pool>
+ */
+int
+zpool_do_reguid(int argc, char **argv)
+{
+	int c;
+	char *poolname;
+	zpool_handle_t *zhp;
+	int ret = 0;
+
+	/* check options */
+	while ((c = getopt(argc, argv, "")) != -1) {
+		switch (c) {
+		case '?':
+			(void) fprintf(stderr, gettext("invalid option '%c'\n"),
+			    optopt);
+			usage(B_FALSE);
+		}
+	}
+
+	argc -= optind;
+	argv += optind;
+
+	/* get pool name and check number of arguments */
+	if (argc < 1) {
+		(void) fprintf(stderr, gettext("missing pool name\n"));
+		usage(B_FALSE);
+	}
+
+	if (argc > 1) {
+		(void) fprintf(stderr, gettext("too many arguments\n"));
+		usage(B_FALSE);
+	}
+
+	poolname = argv[0];
+	if ((zhp = zpool_open(g_zfs, poolname)) == NULL)
+		return (1);
+
+	ret = zpool_reguid(zhp);
+
+	zpool_close(zhp);
+	return (ret);
+}
+
+
 typedef struct scrub_cbdata {
 	int	cb_type;
 	int	cb_argc;
diff --git a/usr/src/cmd/ztest/ztest.c b/usr/src/cmd/ztest/ztest.c
index bc29b39232..d78ede3557 100644
--- a/usr/src/cmd/ztest/ztest.c
+++ b/usr/src/cmd/ztest/ztest.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.
  */
 
 /*
@@ -257,6 +258,7 @@ ztest_func_t ztest_vdev_LUN_growth;
 ztest_func_t ztest_vdev_add_remove;
 ztest_func_t ztest_vdev_aux_add_remove;
 ztest_func_t ztest_split_pool;
+ztest_func_t ztest_reguid;
 
 uint64_t zopt_always = 0ULL * NANOSEC;		/* all the time */
 uint64_t zopt_incessant = 1ULL * NANOSEC / 10;	/* every 1/10 second */
@@ -287,6 +289,7 @@ ztest_info_t ztest_info[] = {
 	{ ztest_fault_inject,			1,	&zopt_sometimes	},
 	{ ztest_ddt_repair,			1,	&zopt_sometimes	},
 	{ ztest_dmu_snapshot_hold,		1,	&zopt_sometimes	},
+	{ ztest_reguid,				1,	&zopt_sometimes },
 	{ ztest_spa_rename,			1,	&zopt_rarely	},
 	{ ztest_scrub,				1,	&zopt_rarely	},
 	{ ztest_dsl_dataset_promote_busy,	1,	&zopt_rarely	},
@@ -323,6 +326,7 @@ typedef struct ztest_shared {
 	uint64_t	zs_vdev_aux;
 	uint64_t	zs_alloc;
 	uint64_t	zs_space;
+	uint64_t	zs_guid;
 	mutex_t		zs_vdev_lock;
 	rwlock_t	zs_name_lock;
 	ztest_info_t	zs_info[ZTEST_FUNCS];
@@ -4641,7 +4645,7 @@ ztest_ddt_repair(ztest_ds_t *zd, uint64_t id)
 
 	object = od[0].od_object;
 	blocksize = od[0].od_blocksize;
-	pattern = spa_guid(spa) ^ dmu_objset_fsid_guid(os);
+	pattern = zs->zs_guid ^ dmu_objset_fsid_guid(os);
 
 	ASSERT(object != 0);
 
@@ -4712,6 +4716,31 @@ ztest_scrub(ztest_ds_t *zd, uint64_t id)
 }
 
 /*
+ * Change the guid for the pool.
+ */
+/* ARGSUSED */
+void
+ztest_reguid(ztest_ds_t *zd, uint64_t id)
+{
+	ztest_shared_t *zs = ztest_shared;
+	spa_t *spa = zs->zs_spa;
+	uint64_t orig, load;
+
+	orig = spa_guid(spa);
+	load = spa_load_guid(spa);
+	if (spa_change_guid(spa) != 0)
+		return;
+
+	if (zopt_verbose >= 3) {
+		(void) printf("Changed guid old %llu -> %llu\n",
+		    (u_longlong_t)orig, (u_longlong_t)spa_guid(spa));
+	}
+
+	VERIFY3U(orig, !=, spa_guid(spa));
+	VERIFY3U(load, ==, spa_load_guid(spa));
+}
+
+/*
  * Rename the pool to a different name and then rename it back.
  */
 /* ARGSUSED */
@@ -5139,6 +5168,7 @@ ztest_run(ztest_shared_t *zs)
 {
 	thread_t *tid;
 	spa_t *spa;
+	objset_t *os;
 	thread_t resume_tid;
 	int error;
 
@@ -5170,6 +5200,10 @@ ztest_run(ztest_shared_t *zs)
 	spa->spa_debug = B_TRUE;
 	zs->zs_spa = spa;
 
+	VERIFY3U(0, ==, dmu_objset_hold(zs->zs_pool, FTAG, &os));
+	zs->zs_guid = dmu_objset_fsid_guid(os);
+	dmu_objset_rele(os, FTAG);
+
 	spa->spa_dedup_ditto = 2 * ZIO_DEDUPDITTO_MIN;
 
 	/*
diff --git a/usr/src/lib/libzfs/common/libzfs.h b/usr/src/lib/libzfs/common/libzfs.h
index 1b5329c3e1..bc353eb875 100644
--- a/usr/src/lib/libzfs/common/libzfs.h
+++ b/usr/src/lib/libzfs/common/libzfs.h
@@ -21,7 +21,8 @@
 
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
- * Copyright 2010 Nexenta Systems, Inc. All rights reserved.
+ * Copyright 2011 Nexenta Systems, Inc. All rights reserved.
+ * Copyright (c) 2011 by Delphix. All rights reserved.
  */
 
 #ifndef	_LIBZFS_H
@@ -230,6 +231,7 @@ typedef struct splitflags {
  */
 extern int zpool_scan(zpool_handle_t *, pool_scan_func_t);
 extern int zpool_clear(zpool_handle_t *, const char *, nvlist_t *);
+extern int zpool_reguid(zpool_handle_t *);
 
 extern int zpool_vdev_online(zpool_handle_t *, const char *, int,
     vdev_state_t *);
diff --git a/usr/src/lib/libzfs/common/libzfs_pool.c b/usr/src/lib/libzfs/common/libzfs_pool.c
index 7df7e910dd..0c7cf30fae 100644
--- a/usr/src/lib/libzfs/common/libzfs_pool.c
+++ b/usr/src/lib/libzfs/common/libzfs_pool.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 <ctype.h>
@@ -2967,6 +2969,26 @@ zpool_vdev_clear(zpool_handle_t *zhp, uint64_t guid)
 }
 
 /*
+ * Change the GUID for a pool.
+ */
+int
+zpool_reguid(zpool_handle_t *zhp)
+{
+	char msg[1024];
+	libzfs_handle_t *hdl = zhp->zpool_hdl;
+	zfs_cmd_t zc = { 0 };
+
+	(void) snprintf(msg, sizeof (msg),
+	    dgettext(TEXT_DOMAIN, "cannot reguid '%s'"), zhp->zpool_name);
+
+	(void) strlcpy(zc.zc_name, zhp->zpool_name, sizeof (zc.zc_name));
+	if (zfs_ioctl(hdl, ZFS_IOC_POOL_REGUID, &zc) == 0)
+		return (0);
+
+	return (zpool_standard_error(hdl, errno, msg));
+}
+
+/*
  * Convert from a devid string to a path.
  */
 static char *
diff --git a/usr/src/lib/libzfs/common/mapfile-vers b/usr/src/lib/libzfs/common/mapfile-vers
index b435b58e05..3014aaeabc 100644
--- a/usr/src/lib/libzfs/common/mapfile-vers
+++ b/usr/src/lib/libzfs/common/mapfile-vers
@@ -19,7 +19,8 @@
 # CDDL HEADER END
 #
 # Copyright (c) 2006, 2010, Oracle and/or its affiliates. All rights reserved.
-# Copyright 2010 Nexenta Systems, Inc. All rights reserved.
+# Copyright 2011 Nexenta Systems, Inc. All rights reserved.
+# Copyright (c) 2011 by Delphix. All rights reserved.
 #
 # MAPFILE HEADER START
 #
@@ -199,6 +200,7 @@ SYMBOL_VERSION SUNWprivate_1.1 {
 	zpool_prop_values;
 	zpool_read_label;
 	zpool_refresh_stats;
+	zpool_reguid;
 	zpool_scan;
 	zpool_search_import;
 	zpool_set_history_str;
diff --git a/usr/src/man/man1m/zpool.1m b/usr/src/man/man1m/zpool.1m
index 4fb81d82d3..52f3f839d2 100644
--- a/usr/src/man/man1m/zpool.1m
+++ b/usr/src/man/man1m/zpool.1m
@@ -3,7 +3,8 @@
 .\" 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]
-.TH ZPOOL 1M "Sep 21, 2009"
+.\" Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
+.TH ZPOOL 1M "Oct 25, 2011"
 .SH NAME
 zpool \- configures ZFS storage pools
 .SH SYNOPSIS
@@ -97,6 +98,11 @@ zpool \- configures ZFS storage pools
 
 .LP
 .nf
+\fBzpool reguid\fR \fIpool\fR
+.fi
+
+.LP
+.nf
 \fBzpool remove\fR \fIpool\fR \fIdevice\fR ...
 .fi
 
@@ -1439,6 +1445,17 @@ become available to the pool.
 .sp
 .ne 2
 .na
+\fB\fBzpool reguid\fR \fIpool\fR
+.ad
+.sp .6
+.RS 4n
+Generates a new unique identifier for the pool.  You must ensure that all devices in this pool are online and
+healthy before performing this action.
+.RE
+
+.sp
+.ne 2
+.na
 \fB\fBzpool remove\fR \fIpool\fR \fIdevice\fR ...\fR
 .ad
 .sp .6
diff --git a/usr/src/uts/common/fs/zfs/arc.c b/usr/src/uts/common/fs/zfs/arc.c
index a82718e8bc..e039b9cac4 100644
--- a/usr/src/uts/common/fs/zfs/arc.c
+++ b/usr/src/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.
  */
 
 /*
@@ -1217,7 +1219,7 @@ 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);
@@ -1919,7 +1921,7 @@ arc_flush(spa_t *spa)
 	uint64_t guid = 0;
 
 	if (spa)
-		guid = spa_guid(spa);
+		guid = spa_load_guid(spa);
 
 	while (list_head(&arc_mru->arcs_list[ARC_BUFC_DATA])) {
 		(void) arc_evict(arc_mru, guid, -1, FALSE, ARC_BUFC_DATA);
@@ -2676,7 +2678,7 @@ 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),
@@ -4234,7 +4236,7 @@ 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);
 
 	ASSERT(dev->l2ad_vdev != NULL);
 
diff --git a/usr/src/uts/common/fs/zfs/spa.c b/usr/src/uts/common/fs/zfs/spa.c
index 5d9332a70b..46ecee05ae 100644
--- a/usr/src/uts/common/fs/zfs/spa.c
+++ b/usr/src/uts/common/fs/zfs/spa.c
@@ -21,9 +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.
  */
 
 /*
@@ -566,6 +565,43 @@ 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)
  * ==========================================================================
@@ -1743,7 +1779,7 @@ 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) {
diff --git a/usr/src/uts/common/fs/zfs/spa_misc.c b/usr/src/uts/common/fs/zfs/spa_misc.c
index 411aba8342..cc77f1bc18 100644
--- a/usr/src/uts/common/fs/zfs/spa_misc.c
+++ b/usr/src/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>
@@ -1304,13 +1305,24 @@ 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/usr/src/uts/common/fs/zfs/sys/spa.h b/usr/src/uts/common/fs/zfs/sys/spa.h
index 04742559fa..a8e797c3aa 100644
--- a/usr/src/uts/common/fs/zfs/sys/spa.h
+++ b/usr/src/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/usr/src/uts/common/fs/zfs/sys/spa_impl.h b/usr/src/uts/common/fs/zfs/sys/spa_impl.h
index 3c8caf5357..1f635dda62 100644
--- a/usr/src/uts/common/fs/zfs/sys/spa_impl.h
+++ b/usr/src/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
@@ -136,7 +137,8 @@ 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/usr/src/uts/common/fs/zfs/vdev.c b/usr/src/uts/common/fs/zfs/vdev.c
index bac3e86054..2456ca857c 100644
--- a/usr/src/uts/common/fs/zfs/vdev.c
+++ b/usr/src/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>
@@ -286,6 +288,7 @@ 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/usr/src/uts/common/fs/zfs/zfs_ioctl.c b/usr/src/uts/common/fs/zfs/zfs_ioctl.c
index 486ae9506d..b546579bc6 100644
--- a/usr/src/uts/common/fs/zfs/zfs_ioctl.c
+++ b/usr/src/uts/common/fs/zfs/zfs_ioctl.c
@@ -22,6 +22,10 @@
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
  * Portions Copyright 2011 Martin Matuska
  */
+/*
+ * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
+ * Copyright (c) 2011 by Delphix. All rights reserved.
+ */
 
 #include <sys/types.h>
 #include <sys/param.h>
@@ -1449,6 +1453,20 @@ 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;
@@ -4745,7 +4763,9 @@ static zfs_ioc_vec_t zfs_ioc_vec[] = {
 	{ zfs_ioc_tmp_snapshot, zfs_secpolicy_tmp_snapshot, DATASET_NAME,
 	    B_FALSE, POOL_CHECK_SUSPENDED | POOL_CHECK_READONLY },
 	{ zfs_ioc_obj_to_stats, zfs_secpolicy_diff, DATASET_NAME, B_FALSE,
-	    POOL_CHECK_SUSPENDED }
+	    POOL_CHECK_SUSPENDED },
+	{ zfs_ioc_pool_reguid, zfs_secpolicy_config, POOL_NAME, B_TRUE,
+	    POOL_CHECK_SUSPENDED | POOL_CHECK_READONLY }
 };
 
 int
diff --git a/usr/src/uts/common/sys/fs/zfs.h b/usr/src/uts/common/sys/fs/zfs.h
index d5b7899feb..f7473d7558 100644
--- a/usr/src/uts/common/sys/fs/zfs.h
+++ b/usr/src/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 */
@@ -776,7 +777,8 @@ typedef enum zfs_ioc {
 	ZFS_IOC_NEXT_OBJ,
 	ZFS_IOC_DIFF,
 	ZFS_IOC_TMP_SNAPSHOT,
-	ZFS_IOC_OBJ_TO_STATS
+	ZFS_IOC_OBJ_TO_STATS,
+	ZFS_IOC_POOL_REGUID
 } zfs_ioc_t;
 
 /*
@@ -839,6 +841,7 @@ 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/usr/src/uts/common/sys/sysevent/eventdefs.h b/usr/src/uts/common/sys/sysevent/eventdefs.h
index 3ed9bb2980..5a75c5d844 100644
--- a/usr/src/uts/common/sys/sysevent/eventdefs.h
+++ b/usr/src/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"
 
 /*
  * datalink subclass definitions.