Kill subarray v2

Support for deleting a subarray out of a container.  When all subarrays
are deleted the component devices are converted back into spares, a
--zero-superblock is still needed to kill the remaining metadata at this
point.  This operation is blocked when the subarray is active and may
also be blocked by the metadata handler when deleting the subarray might
change the uuid of other active subarrays.  For example, with imsm,
deleting subarray 'n' may change the uuid of subarrays with indexes > n.

Deleting a subarray needs to be a container wide event to ensure
disks that record the modified subarray list perceive other disks that
did not receive this change as out of date.

Notes:
The st->subarray parsing in super-intel.c and super-ddf.c is updated to
be more strict now that we are reading user supplied subarray values.

Offline container modification shares actions that mdmon typically
handles so promote is_container_member() and version_to_superswitch()
(formerly find_metadata_methods()) to generic utility functions for the
cases where mdadm performs the operation.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>

1 files changed, 78 insertions, 0 deletions

diff --git a/Kill.c b/Kill.c
index e738978..b3344bd 100644
--- a/Kill.c
+++ b/Kill.c
@@ -79,3 +79,81 @@ int Kill(char *dev, struct supertype *st, int force, int quiet, int noexcl)
 	close(fd);
 	return rv;
 }
+
+int Kill_subarray(char *dev, char *subarray, int quiet)
+{
+	/* Delete a subarray out of a container, the subarry must be
+	 * inactive.  The subarray string must be a subarray index
+	 * number.
+	 *
+	 * 0 = successfully deleted subarray from all container members
+	 * 1 = failed to sync metadata to one or more devices
+	 * 2 = failed to find the container, subarray, or other resource
+	 *     issue
+	 */
+	struct supertype supertype, *st = &supertype;
+	int fd, rv = 2;
+
+	memset(st, 0, sizeof(*st));
+
+	if (snprintf(st->subarray, sizeof(st->subarray), "%s", subarray) >=
+	    sizeof(st->subarray)) {
+		if (!quiet)
+			fprintf(stderr,
+				Name ": Input overflow for subarray '%s' > %zu bytes\n",
+				subarray, sizeof(st->subarray) - 1);
+		return 2;
+	}
+
+	fd = open_subarray(dev, st, quiet);
+	if (fd < 0)
+		return 2;
+
+	if (!st->ss->kill_subarray) {
+		if (!quiet)
+			fprintf(stderr,
+				Name ": Operation not supported for %s metadata\n",
+				st->ss->name);
+		goto free_super;
+	}
+
+	if (is_subarray_active(subarray, st->devname)) {
+		if (!quiet)
+			fprintf(stderr,
+				Name ": Subarray-%s still active, aborting\n",
+				subarray);
+		goto free_super;
+	}
+
+	if (mdmon_running(st->devnum))
+		st->update_tail = &st->updates;
+
+	/* ok we've found our victim, drop the axe */
+	rv = st->ss->kill_subarray(st);
+	if (rv) {
+		if (!quiet)
+			fprintf(stderr,
+				Name ": Failed to delete subarray-%s from %s\n",
+				subarray, dev);
+		goto free_super;
+	}
+
+	/* FIXME these routines do not report success/failure */
+	if (st->update_tail)
+		flush_metadata_updates(st);
+	else
+		st->ss->sync_metadata(st);
+
+	if (!quiet)
+		fprintf(stderr,
+			Name ": Deleted subarray-%s from %s, UUIDs may have changed\n",
+			subarray, dev);
+
+	rv = 0;
+
+ free_super:
+	st->ss->free_super(st);
+	close(fd);
+
+	return rv;
+}