MFC r332426: allow ZFS pool to have temporary name for duration of current import

The change adds -t <name> option to zpool create and -t option to zpool
import in its form with an old name and a new name.  This allows to
import (or create) a pool under a name that's different from its real,
permanent name without affecting that name.  This is useful when working
with VM images or images of other physical systems if they happen to
have a ZFS pool with the same name as the host system.

Sponsored by:	Panzura (porting)

3 files changed, 106 insertions, 24 deletions

diff --git a/cddl/contrib/opensolaris/cmd/zpool/zpool.8 b/cddl/contrib/opensolaris/cmd/zpool/zpool.8
index 168b936..f40473d 100644
--- a/cddl/contrib/opensolaris/cmd/zpool/zpool.8
+++ b/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
@@ -966,6 +968,7 @@ do not actually discard any transactions.
 .Ar ...
 .Op Fl m Ar mountpoint
 .Op Fl R Ar root
+.Op Fl t Ar tempname
 .Ar pool vdev ...
 .Xc
 .Pp
@@ -1067,6 +1070,18 @@ or
 .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
@@ -1321,6 +1336,7 @@ Searches for and imports all pools found.
 .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
@@ -1380,6 +1396,20 @@ Import the pool without mounting any file systems.
 .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
diff --git a/cddl/contrib/opensolaris/cmd/zpool/zpool_main.c b/cddl/contrib/opensolaris/cmd/zpool/zpool_main.c
index 51edeca..582b4f0 100644
--- a/cddl/contrib/opensolaris/cmd/zpool/zpool_main.c
+++ b/cddl/contrib/opensolaris/cmd/zpool/zpool_main.c
@@ -220,8 +220,9 @@ get_usage(zpool_help_t idx)
 	case HELP_CREATE:
 		return (gettext("\tcreate [-fnd] [-B] "
 		    "[-o property=value] ... \n"
-		    "\t    [-O file-system-property=value] ... \n"
-		    "\t    [-m mountpoint] [-R root] <pool> <vdev> ...\n"));
+		    "\t    [-O file-system-property=value] ...\n"
+		    "\t    [-m mountpoint] [-R root] [-t tempname] "
+		    "<pool> <vdev> ...\n"));
 	case HELP_CHECKPOINT:
 		return (gettext("\tcheckpoint [--discard] <pool> ...\n"));
 	case HELP_DESTROY:
@@ -239,7 +240,7 @@ get_usage(zpool_help_t idx)
 		    "[-R root] [-F [-n]] -a\n"
 		    "\timport [-o mntopts] [-o property=value] ... \n"
 		    "\t    [-d dir | -c cachefile] [-D] [-f] [-m] [-N] "
-		    "[-R root] [-F [-n]]\n"
+		    "[-R root] [-F [-n]] [-t]\n"
 		    "\t    [--rewind-to-checkpoint] <pool | id> [newpool]\n"));
 	case HELP_IOSTAT:
 		return (gettext("\tiostat [-v] [-T d|u] [pool] ... [interval "
@@ -489,6 +490,21 @@ add_prop_list(const char *propname, char *propval, nvlist_t **props,
 }
 
 /*
+ * 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, poolprop));
+}
+
+/*
  * zpool add [-fn] <pool> <vdev> ...
  *
  *	-f	Force addition of devices, even if they appear in use
@@ -850,15 +866,16 @@ errout:
 /*
  * zpool create [-fnd] [-B] [-o property=value] ...
  *		[-O file-system-property=value] ...
- *		[-R root] [-m mountpoint] <pool> <dev> ...
+ *		[-R root] [-m mountpoint] [-t tempname] <pool> <dev> ...
  *
  *	-B	Create boot partition.
  *	-f	Force creation, even if devices appear in use
  *	-n	Do not create the pool, but display the resulting layout if it
  *		were to be created.
- *      -R	Create a pool under an alternate root
- *      -m	Set default mountpoint for the root dataset.  By default it's
+ *	-R	Create a pool under an alternate root
+ *	-m	Set default mountpoint for the root dataset.  By default it's
  *		'/<pool>'
+ *	-t	Use the temporary name until the pool is exported.
  *	-o	Set property=value.
  *	-d	Don't automatically enable all supported pool features
  *		(individual features can be enabled with -o).
@@ -882,6 +899,7 @@ zpool_do_create(int argc, char **argv)
 	int c;
 	nvlist_t *nvroot = NULL;
 	char *poolname;
+	char *tname = NULL;
 	int ret = 1;
 	char *altroot = NULL;
 	char *mountpoint = NULL;
@@ -890,7 +908,7 @@ zpool_do_create(int argc, char **argv)
 	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 +940,7 @@ zpool_do_create(int argc, char **argv)
 			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 +1013,27 @@ zpool_do_create(int argc, char **argv)
 				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 +1240,8 @@ zpool_do_create(int argc, char **argv)
 		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);
@@ -2162,7 +2197,8 @@ zpool_do_checkpoint(int argc, char **argv)
  *       import [-o mntopts] [-o prop=value] ... [-R root] [-D]
  *              [-d dir | -c cachefile] [-f] -a
  *       import [-o mntopts] [-o prop=value] ... [-R root] [-D]
- *              [-d dir | -c cachefile] [-f] [-n] [-F] <pool | id> [newpool]
+ *              [-d dir | -c cachefile] [-f] [-n] [-F] [-t]
+ *              <pool | id> [newpool]
  *
  *	 -c	Read pool information from a cachefile instead of searching
  *		devices.
@@ -2191,6 +2227,9 @@ zpool_do_checkpoint(int argc, char **argv)
  *
  *       -N     Import the pool but don't mount datasets.
  *
+ *       -t     Use newpool as a temporary pool name instead of renaming
+ *       	the pool.
+ *
  *       -T     Specify a starting txg to use for import. This option is
  *       	intentionally undocumented option for testing purposes.
  *
@@ -2241,7 +2280,7 @@ zpool_do_import(int argc, char **argv)
 	};
 
 	/* 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 +2335,13 @@ zpool_do_import(int argc, char **argv)
 			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;
@@ -2439,9 +2480,9 @@ zpool_do_import(int argc, char **argv)
 		(void) fprintf(stderr, gettext("cannot import '%s': "
 		    "a pool with that name already exists\n"),
 		    argv[0]);
-		(void) fprintf(stderr, gettext("use the form '%s "
-		    "<pool | id> <newpool>' to give it a new name\n"),
-		    "zpool import");
+		(void) fprintf(stderr, gettext("use the form 'zpool import "
+		    "[-t] <pool | id> <newpool>' to give it a new temporary "
+		    "or permanent name\n"));
 		err = 1;
 	} else if (pools == NULL && idata.exists) {
 		(void) fprintf(stderr, gettext("cannot import '%s': "
diff --git a/cddl/contrib/opensolaris/lib/libzfs/common/libzfs_pool.c b/cddl/contrib/opensolaris/lib/libzfs/common/libzfs_pool.c
index 61c5325..1eec116 100644
--- a/cddl/contrib/opensolaris/lib/libzfs/common/libzfs_pool.c
+++ b/cddl/contrib/opensolaris/lib/libzfs/common/libzfs_pool.c
@@ -644,6 +644,7 @@ zpool_valid_proplist(libzfs_handle_t *hdl, const char *poolname,
 				goto error;
 			}
 			break;
+
 		case ZPOOL_PROP_READONLY:
 			if (!flags.import) {
 				zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
@@ -654,6 +655,16 @@ zpool_valid_proplist(libzfs_handle_t *hdl, const char *poolname,
 			}
 			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;
+
 		default:
 			zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
 			    "property '%s'(%d) not defined"), propname, prop);