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did not receive this change as out of date.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, 2 insertions, 23 deletions

diff --git a/mdmon.c b/mdmon.c
index 69c320e6..beb39cfc 100644
--- a/mdmon.c
+++ b/mdmon.c
@@ -104,15 +104,6 @@ int __clone2(int (*fn)(void *),
 	return mon_tid;
 }
 
-static struct superswitch *find_metadata_methods(char *vers)
-{
-	if (strcmp(vers, "ddf") == 0)
-		return &super_ddf;
-	if (strcmp(vers, "imsm") == 0)
-		return &super_imsm;
-	return NULL;
-}
-
 static int make_pidfile(char *devname)
 {
 	char path[100];
@@ -136,18 +127,6 @@ static int make_pidfile(char *devname)
 	return 0;
 }
 
-int is_container_member(struct mdstat_ent *mdstat, char *container)
-{
-	if (mdstat->metadata_version == NULL ||
-	    strncmp(mdstat->metadata_version, "external:", 9) != 0 ||
-	    !is_subarray(mdstat->metadata_version+9) ||
-	    strncmp(mdstat->metadata_version+10, container, strlen(container)) != 0 ||
-	    mdstat->metadata_version[10+strlen(container)] != '/')
-		return 0;
-
-	return 1;
-}
-
 static void try_kill_monitor(pid_t pid, char *devname, int sock)
 {
 	char buf[100];
@@ -414,9 +393,9 @@ static int mdmon(char *devname, int devnum, int must_fork, int takeover)
 		exit(3);
 	}
 
-	container->ss = find_metadata_methods(mdi->text_version);
+	container->ss = version_to_superswitch(mdi->text_version);
 	if (container->ss == NULL) {
-		fprintf(stderr, "mdmon: %s uses unknown metadata: %s\n",
+		fprintf(stderr, "mdmon: %s uses unsupported metadata: %s\n",
 			devname, mdi->text_version);
 		exit(3);
 	}