Index: cddl/contrib/opensolaris/cmd/zpool/zpool.8
===================================================================
--- cddl/contrib/opensolaris/cmd/zpool/zpool.8
+++ cddl/contrib/opensolaris/cmd/zpool/zpool.8
@@ -62,6 +62,7 @@
 .Ar ...
 .Op Fl m Ar mountpoint
 .Op Fl R Ar root
+.Op Fl t Ar tempname
 .Ar pool vdev ...
 .Nm
 .Cm destroy
@@ -115,6 +116,7 @@
 .Op Fl m
 .Op Fl N
 .Op Fl R Ar root
+.Op Fl t
 .Op Fl F Op Fl n
 .Ar pool | id
 .Op Ar newpool
@@ -961,6 +963,7 @@
 .Ar ...
 .Op Fl m Ar mountpoint
 .Op Fl R Ar root
+.Op Fl t Ar tempname
 .Ar pool vdev ...
 .Xc
 .Pp
@@ -1062,6 +1065,18 @@
 .Qq Cm none .
 For more information on dataset mount points, see
 .Xr zfs 8 .
+.It Fl t Ar tempname
+Sets the in-core pool name to
+.Pa tempname
+while the on-disk name will be the name specified as the pool name
+.Pa pool .
+This will set the default
+.Sy cachefile
+property to
+.Sy none .
+This is intended to handle name space collisions when creating pools
+for other systems, such as virtual machines or physical machines
+whose pools live on network block devices.
 .El
 .It Xo
 .Nm
@@ -1316,6 +1331,7 @@
 .Op Fl m
 .Op Fl N
 .Op Fl R Ar root
+.Op Fl t
 .Op Fl F Op Fl n
 .Ar pool | id
 .Op Ar newpool
@@ -1375,6 +1391,20 @@
 .It Fl R Ar root
 Equivalent to
 .Qq Fl o Cm cachefile=none,altroot= Ns Pa root
+.It Fl t
+Used with
+.Ar newpool .
+Specifies that
+.Ar newpool
+is temporary.
+Temporary pool names last until export.
+Ensures that the original pool name will be used in all label updates and
+therefore is retained upon export.
+Will also set
+.Sy cachefile
+property to
+.Sy none
+when not explicitly specified.
 .It Fl F
 Recovery mode for a non-importable pool. Attempt to return the pool to an
 importable state by discarding the last few transactions. Not all damaged pools
Index: cddl/contrib/opensolaris/cmd/zpool/zpool_main.c
===================================================================
--- cddl/contrib/opensolaris/cmd/zpool/zpool_main.c
+++ cddl/contrib/opensolaris/cmd/zpool/zpool_main.c
@@ -489,6 +489,21 @@
 }
 
 /*
+ * Set a default property pair (name, string-value) in a property nvlist
+ */
+static int
+add_prop_list_default(const char *propname, char *propval, nvlist_t **props,
+    boolean_t poolprop)
+{
+	char *pval;
+
+	if (nvlist_lookup_string(*props, propname, &pval) == 0)
+		return (0);
+
+	return (add_prop_list(propname, propval, props, B_TRUE));
+}
+
+/*
  * zpool add [-fn] <pool> <vdev> ...
  *
  *	-f	Force addition of devices, even if they appear in use
@@ -882,6 +897,7 @@
 	int c;
 	nvlist_t *nvroot = NULL;
 	char *poolname;
+	char *tname = NULL;
 	int ret = 1;
 	char *altroot = NULL;
 	char *mountpoint = NULL;
@@ -890,7 +906,7 @@
 	char *propval;
 
 	/* check options */
-	while ((c = getopt(argc, argv, ":fndBR:m:o:O:")) != -1) {
+	while ((c = getopt(argc, argv, ":fndBR:m:o:O:t:")) != -1) {
 		switch (c) {
 		case 'f':
 			force = B_TRUE;
@@ -922,11 +938,7 @@
 			if (add_prop_list(zpool_prop_to_name(
 			    ZPOOL_PROP_ALTROOT), optarg, &props, B_TRUE))
 				goto errout;
-			if (nvlist_lookup_string(props,
-			    zpool_prop_to_name(ZPOOL_PROP_CACHEFILE),
-			    &propval) == 0)
-				break;
-			if (add_prop_list(zpool_prop_to_name(
+			if (add_prop_list_default(zpool_prop_to_name(
 			    ZPOOL_PROP_CACHEFILE), "none", &props, B_TRUE))
 				goto errout;
 			break;
@@ -999,6 +1011,27 @@
 				goto errout;
 			}
 			break;
+		case 't':
+			/*
+			 * Sanity check temporary pool name.
+			 */
+			if (strchr(optarg, '/') != NULL) {
+				(void) fprintf(stderr, gettext("cannot create "
+				    "'%s': invalid character '/' in temporary "
+				    "name\n"), optarg);
+				(void) fprintf(stderr, gettext("use 'zfs "
+				    "create' to create a dataset\n"));
+				goto errout;
+			}
+
+			if (add_prop_list(zpool_prop_to_name(
+			    ZPOOL_PROP_TNAME), optarg, &props, B_TRUE))
+				goto errout;
+			if (add_prop_list_default(zpool_prop_to_name(
+			    ZPOOL_PROP_CACHEFILE), "none", &props, B_TRUE))
+				goto errout;
+			tname = optarg;
+			break;
 		case ':':
 			(void) fprintf(stderr, gettext("missing argument for "
 			    "'%c' option\n"), optopt);
@@ -1205,8 +1238,8 @@
 		ret = 1;
 		if (zpool_create(g_zfs, poolname,
 		    nvroot, props, fsprops) == 0) {
-			zfs_handle_t *pool = zfs_open(g_zfs, poolname,
-			    ZFS_TYPE_FILESYSTEM);
+			zfs_handle_t *pool = zfs_open(g_zfs,
+			    tname ? tname : poolname, ZFS_TYPE_FILESYSTEM);
 			if (pool != NULL) {
 				if (zfs_mount(pool, NULL, 0) == 0)
 					ret = zfs_shareall(pool);
@@ -2241,7 +2274,7 @@
 	};
 
 	/* check options */
-	while ((c = getopt_long(argc, argv, ":aCc:d:DEfFmnNo:rR:T:VX",
+	while ((c = getopt_long(argc, argv, ":aCc:d:DEfFmnNo:rR:tT:VX",
 	    long_options, NULL)) != -1) {
 		switch (c) {
 		case 'a':
@@ -2296,11 +2329,13 @@
 			if (add_prop_list(zpool_prop_to_name(
 			    ZPOOL_PROP_ALTROOT), optarg, &props, B_TRUE))
 				goto error;
-			if (nvlist_lookup_string(props,
-			    zpool_prop_to_name(ZPOOL_PROP_CACHEFILE),
-			    &propval) == 0)
-				break;
-			if (add_prop_list(zpool_prop_to_name(
+			if (add_prop_list_default(zpool_prop_to_name(
+			    ZPOOL_PROP_CACHEFILE), "none", &props, B_TRUE))
+				goto error;
+			break;
+		case 't':
+			flags |= ZFS_IMPORT_TEMP_NAME;
+			if (add_prop_list_default(zpool_prop_to_name(
 			    ZPOOL_PROP_CACHEFILE), "none", &props, B_TRUE))
 				goto error;
 			break;
Index: cddl/contrib/opensolaris/lib/libzfs/common/libzfs_pool.c
===================================================================
--- cddl/contrib/opensolaris/lib/libzfs/common/libzfs_pool.c
+++ cddl/contrib/opensolaris/lib/libzfs/common/libzfs_pool.c
@@ -658,6 +658,15 @@
 			zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
 			    "property '%s'(%d) not defined"), propname, prop);
 			break;
+		case ZPOOL_PROP_TNAME:
+			if (!flags.create) {
+				zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
+				    "property '%s' can only be set at "
+				    "creation time"), propname);
+				(void) zfs_error(hdl, EZFS_BADPROP, errbuf);
+				goto error;
+			}
+			break;
 		}
 	}
 
Index: sys/cddl/contrib/opensolaris/common/zfs/zpool_prop.c
===================================================================
--- sys/cddl/contrib/opensolaris/common/zfs/zpool_prop.c
+++ sys/cddl/contrib/opensolaris/common/zfs/zpool_prop.c
@@ -136,6 +136,8 @@
 	    PROP_READONLY, ZFS_TYPE_POOL, "NAME");
 	zprop_register_hidden(ZPOOL_PROP_MAXBLOCKSIZE, "maxblocksize",
 	    PROP_TYPE_NUMBER, PROP_READONLY, ZFS_TYPE_POOL, "MAXBLOCKSIZE");
+	zprop_register_hidden(ZPOOL_PROP_TNAME, "tname", PROP_TYPE_STRING,
+	    PROP_ONETIME, ZFS_TYPE_POOL, "TNAME");
 }
 
 /*
Index: sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa.c
===================================================================
--- sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa.c
+++ sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa.c
@@ -4666,12 +4666,17 @@
 	uint_t nspares, nl2cache;
 	uint64_t version, obj;
 	boolean_t has_features;
+	char *poolname;
+	nvlist_t *nvl;
 
+	if (nvlist_lookup_string(props, "tname", &poolname) != 0)
+		poolname = (char *)pool;
+
 	/*
 	 * If this pool already exists, return failure.
 	 */
 	mutex_enter(&spa_namespace_lock);
-	if (spa_lookup(pool) != NULL) {
+	if (spa_lookup(poolname) != NULL) {
 		mutex_exit(&spa_namespace_lock);
 		return (SET_ERROR(EEXIST));
 	}
@@ -4679,9 +4684,12 @@
 	/*
 	 * Allocate a new spa_t structure.
 	 */
+	nvl = fnvlist_alloc();
+	fnvlist_add_string(nvl, ZPOOL_CONFIG_POOL_NAME, pool);
 	(void) nvlist_lookup_string(props,
 	    zpool_prop_to_name(ZPOOL_PROP_ALTROOT), &altroot);
-	spa = spa_add(pool, NULL, altroot);
+	spa = spa_add(poolname, nvl, altroot);
+	fnvlist_free(nvl);
 	spa_activate(spa, spa_mode_global);
 
 	if (props && (error = spa_prop_validate(spa, props))) {
@@ -4690,6 +4698,12 @@
 		mutex_exit(&spa_namespace_lock);
 		return (error);
 	}
+
+	/*
+	 * Temporary pool names should never be written to disk.
+	 */
+	if (poolname != pool)
+		spa->spa_import_flags |= ZFS_IMPORT_TEMP_NAME;
 
 	has_features = B_FALSE;
 	for (nvpair_t *elem = nvlist_next_nvpair(props, NULL);
Index: sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa_config.c
===================================================================
--- sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa_config.c
+++ sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa_config.c
@@ -226,6 +226,7 @@
 	nvlist_t *nvl;
 	boolean_t ccw_failure;
 	int error;
+	char *pool_name;
 
 	ASSERT(MUTEX_HELD(&spa_namespace_lock));
 
@@ -274,11 +275,18 @@
 			if (nvl == NULL)
 				nvl = fnvlist_alloc();
 
-			fnvlist_add_nvlist(nvl, spa->spa_name,
+			if (spa->spa_import_flags & ZFS_IMPORT_TEMP_NAME) {
+				pool_name = fnvlist_lookup_string(spa->spa_config,
+					ZPOOL_CONFIG_POOL_NAME);
+			} else {
+				pool_name = spa_name(spa);
+			}
+
+			fnvlist_add_nvlist(nvl, pool_name,
 			    spa->spa_config);
 			mutex_exit(&spa->spa_props_lock);
 
-			if (nvlist_lookup_nvlist(nvl, spa->spa_name, &nvroot) == 0)
+			if (nvlist_lookup_nvlist(nvl, pool_name, &nvroot) == 0)
 				spa_config_clean(nvroot);
 		}
 
@@ -382,6 +390,7 @@
 	unsigned long hostid = 0;
 	boolean_t locked = B_FALSE;
 	uint64_t split_guid;
+	char *pool_name;
 
 	if (vd == NULL) {
 		vd = rvd;
@@ -398,10 +407,27 @@
 	if (txg == -1ULL)
 		txg = spa->spa_config_txg;
 
+	/*
+	 * Originally, users had to handle spa namespace collisions by either
+	 * exporting the already imported pool or by specifying a new name for
+	 * the pool with a conflicting name. In the case of root pools from
+	 * virtual guests, neither approach to collision resolution is
+	 * reasonable. This is addressed by extending the new name syntax with
+	 * an option to specify that the new name is temporary. When specified,
+	 * ZFS_IMPORT_TEMP_NAME will be set in spa->spa_import_flags to tell us
+	 * to use the previous name, which we do below.
+	 */
+	if (spa->spa_import_flags & ZFS_IMPORT_TEMP_NAME) {
+		pool_name = fnvlist_lookup_string(spa->spa_config,
+			ZPOOL_CONFIG_POOL_NAME);
+	} else {
+		pool_name = spa_name(spa);
+	}
+
 	config = fnvlist_alloc();
 
 	fnvlist_add_uint64(config, ZPOOL_CONFIG_VERSION, spa_version(spa));
-	fnvlist_add_string(config, ZPOOL_CONFIG_POOL_NAME, spa_name(spa));
+	fnvlist_add_string(config, ZPOOL_CONFIG_POOL_NAME, pool_name);
 	fnvlist_add_uint64(config, ZPOOL_CONFIG_POOL_STATE, spa_state(spa));
 	fnvlist_add_uint64(config, ZPOOL_CONFIG_POOL_TXG, txg);
 	fnvlist_add_uint64(config, ZPOOL_CONFIG_POOL_GUID, spa_guid(spa));
Index: sys/cddl/contrib/opensolaris/uts/common/sys/fs/zfs.h
===================================================================
--- sys/cddl/contrib/opensolaris/uts/common/sys/fs/zfs.h
+++ sys/cddl/contrib/opensolaris/uts/common/sys/fs/zfs.h
@@ -214,6 +214,7 @@
 	ZPOOL_PROP_MAXBLOCKSIZE,
 	ZPOOL_PROP_BOOTSIZE,
 	ZPOOL_PROP_CHECKPOINT,
+	ZPOOL_PROP_TNAME,
 	ZPOOL_NUM_PROPS
 } zpool_prop_t;
 
@@ -1047,6 +1048,7 @@
 #define	ZFS_IMPORT_MISSING_LOG	0x4
 #define	ZFS_IMPORT_ONLY		0x8
 #define	ZFS_IMPORT_CHECKPOINT	0x10
+#define	ZFS_IMPORT_TEMP_NAME	0x20
 
 /*
  * Channel program argument/return nvlist keys and defaults.