cddl/contrib/opensolaris/cmd/zpool/zpool_main.c:

cddl/contrib/opensolaris/cmd/zpool/zpool.8:
cddl/contrib/opensolaris/lib/libzfs/common/libzfs_import.c:
	Add the "zpool labelclear" command.  This command can be
	used to wipe the label data from a drive that is not
	active in a pool.  The optional "-f" argument can be
	used to treat an exported or foreign vdev as "inactive"
	thus allowing its label information to be cleared.

cddl/contrib/opensolaris/cmd/zpool/zpool.8

@@ -80,6 +80,11 @@ zpool \- configures ZFS storage pools
 \fBzpool iostat\fR [\fB-T\fR u | d ] [\fB-v\fR] [\fIpool\fR] ... [\fIinterval\fR[\fIcount\fR]]
 .fi
 
+.LP
+.nf
+\fBzpool labelclear\fR [\fB-f\fR] \fIdevice\fR
+.fi
+
 .LP
 .nf
 \fBzpool list\fR [\fB-H\fR] [\fB-o\fR \fIproperty\fR[,...]] [\fIpool\fR] ...
@@ -1201,6 +1206,28 @@ Verbose statistics. Reports usage statistics for individual \fIvdevs\fR within t
 
 .RE
 
+.sp
+.ne 2
+.mk
+.na
+\fB\fBzpool labelclear\fR [\fB-f\fR] \fIdevice\fR
+.ad
+.sp .6
+.RS 4n
+Removes ZFS label information from the specified device. The device must not be part of an active pool configuration.
+.sp
+.ne 2
+.mk
+.na
+\fB\fB-f\fR\fR
+.ad
+.RS 12n
+.rt  
+Treat exported or foreign devices as inactive.
+.RE
+
+.RE
+
 .sp
 .ne 2
 .mk

cddl/contrib/opensolaris/cmd/zpool/zpool_main.c

@@ -57,6 +57,7 @@ static int zpool_do_destroy(int, char **);
 
 static int zpool_do_add(int, char **);
 static int zpool_do_remove(int, char **);
+static int zpool_do_labelclear(int, char **);
 
 static int zpool_do_list(int, char **);
 static int zpool_do_iostat(int, char **);
@@ -113,6 +114,7 @@ typedef enum {
 	HELP_HISTORY,
 	HELP_IMPORT,
 	HELP_IOSTAT,
+	HELP_LABELCLEAR,
 	HELP_LIST,
 	HELP_OFFLINE,
 	HELP_ONLINE,
@@ -149,6 +151,8 @@ static zpool_command_t command_table[] = {
 	{ "add",	zpool_do_add,		HELP_ADD		},
 	{ "remove",	zpool_do_remove,	HELP_REMOVE		},
 	{ NULL },
+	{ "labelclear",	zpool_do_labelclear,	HELP_LABELCLEAR		},
+	{ NULL },
 	{ "list",	zpool_do_list,		HELP_LIST		},
 	{ "iostat",	zpool_do_iostat,	HELP_IOSTAT		},
 	{ "status",	zpool_do_status,	HELP_STATUS		},
@@ -215,6 +219,8 @@ get_usage(zpool_help_t idx) {
 	case HELP_IOSTAT:
 		return (gettext("\tiostat [-v] [-T d|u] [pool] ... [interval "
 		    "[count]]\n"));
+	case HELP_LABELCLEAR:
+		return (gettext("\tlabelclear [-f] <vdev>\n"));
 	case HELP_LIST:
 		return (gettext("\tlist [-H] [-o property[,...]] "
 		    "[-T d|u] [pool] ... [interval [count]]\n"));
@@ -560,6 +566,125 @@ zpool_do_remove(int argc, char **argv)
 	return (ret);
 }
 
+/*
+ * zpool labelclear <vdev>
+ *
+ * Verifies that the vdev is not active and zeros out the label information
+ * on the device.
+ */
+int
+zpool_do_labelclear(int argc, char **argv)
+{
+	char *vdev, *name;
+	int c, fd = -1, ret = 0;
+	pool_state_t state;
+	boolean_t inuse = B_FALSE;
+	boolean_t force = B_FALSE;
+
+	/* check options */
+	while ((c = getopt(argc, argv, "f")) != -1) {
+		switch (c) {
+		case 'f':
+			force = B_TRUE;
+			break;
+		default:
+			(void) fprintf(stderr, gettext("invalid option '%c'\n"),
+			    optopt);
+			usage(B_FALSE);
+		}
+	}
+
+	argc -= optind;
+	argv += optind;
+
+	/* get vdev name */
+	if (argc < 1) {
+		(void) fprintf(stderr, gettext("missing vdev device name\n"));
+		usage(B_FALSE);
+	}
+
+	vdev = argv[0];
+	if ((fd = open(vdev, O_RDWR)) < 0) {
+		(void) fprintf(stderr, gettext("Unable to open %s\n"), vdev);
+		return (B_FALSE);
+	}
+
+	name = NULL;
+	if (zpool_in_use(g_zfs, fd, &state, &name, &inuse) != 0) {
+		if (force)
+			goto wipe_label;
+
+		(void) fprintf(stderr,
+		    gettext("Unable to determine pool state for %s\n"
+		    "Use -f to force the clearing any label data\n"), vdev);
+
+		return (1);
+	}
+
+	if (inuse) {
+		switch (state) {
+		default:
+		case POOL_STATE_ACTIVE:
+		case POOL_STATE_SPARE:
+		case POOL_STATE_L2CACHE:
+			(void) fprintf(stderr,
+gettext("labelclear operation failed.\n"
+	"\tVdev %s is a member (%s), of pool \"%s\".\n"
+	"\tTo remove label information from this device, export or destroy\n"
+	"\tthe pool, or remove %s from the configuration of this pool\n"
+	"\tand retry the labelclear operation\n"),
+			    vdev, zpool_pool_state_to_name(state), name, vdev);
+			ret = 1;
+			goto errout;
+
+		case POOL_STATE_EXPORTED:
+			if (force)
+				break;
+
+			(void) fprintf(stderr,
+gettext("labelclear operation failed.\n"
+	"\tVdev %s is a member of the exported pool \"%s\".\n"
+	"\tUse \"zpool labelclear -f %s\" to force the removal of label\n"
+	"\tinformation.\n"),
+			    vdev, name, vdev);
+			ret = 1;
+			goto errout;
+
+		case POOL_STATE_POTENTIALLY_ACTIVE:
+			if (force)
+				break;
+
+			(void) fprintf(stderr,
+gettext("labelclear operation failed.\n"
+	"\tVdev %s is a member of the pool \"%s\".\n"
+	"\tThis pool is unknown to this system, but may be active on\n"
+	"\tanother system. Use \'zpool labelclear -f %s\' to force the\n"
+	"\tremoval of label information.\n"),
+			    vdev, name, vdev);
+			ret = 1;
+			goto errout;
+
+		case POOL_STATE_DESTROYED:
+			/* inuse should never be set for a destoryed pool... */
+			break;
+		}
+	}
+
+wipe_label:
+	if (zpool_clear_label(fd) != 0) {
+		(void) fprintf(stderr,
+		    gettext("Label clear failed on vdev %s\n"), vdev);
+		ret = 1;
+	}
+
+errout:
+	close(fd);
+	if (name != NULL)
+		free(name);
+
+	return (ret);
+}
+
 /*
  * zpool create [-fn] [-o property=value] ...
  *		[-O file-system-property=value] ...

cddl/contrib/opensolaris/lib/libzfs/common/libzfs_import.c

@@ -1084,8 +1084,8 @@ zpool_open_func(void *arg)
 
 /*
  * Given a file descriptor, clear (zero) the label information.  This function
- * is currently only used in the appliance stack as part of the ZFS sysevent
- * module.
+ * is used in the appliance stack as part of the ZFS sysevent module and
+ * to implement the "zpool labelclear" command.
  */
 int
 zpool_clear_label(int fd)