fix RebuildMap() to retrieve 'subarray' info

RebuildMap falsely returns container info for member arrays.  Retrieving
the subarray and container_dev details prior to ->load_super() changes the
result from:

md127 imsm 082c6371:74b5ce03:64972e41:6b0860d5 /dev/md/imsm
md126 imsm 082c6371:74b5ce03:64972e41:6b0860d5 /dev/md/vol0

...to:

md126 /md127/0 3e03aee2:78c3c593:1e8ecaf0:eefb53ed /dev/md/vol0
md127 imsm 082c6371:74b5ce03:64972e41:6b0860d5 /dev/md/imsm

Reported-by: Ignacy Kasperowicz <ignacy.kasperowicz@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

1 files changed, 31 insertions, 1 deletions

diff --git a/mapfile.c b/mapfile.c
index 601c4ccf..a3038be5 100644
--- a/mapfile.c
+++ b/mapfile.c
@@ -297,6 +297,34 @@ struct map_ent *map_by_name(struct map_ent **map, char *name)
 	return NULL;
 }
 
+/* sets the proper subarray and container_dev according to the metadata
+ * version super_by_fd does this automatically, this routine is meant as
+ * a supplement for guess_super()
+ */
+static void set_member_info(struct supertype *st, struct mdstat_ent *ent)
+{
+	char version[strlen(ent->metadata_version)+1];
+
+	st->subarray[0] = '\0';
+
+	if (strncmp(ent->metadata_version, "external:", 9) != 0)
+		return;
+
+	strcpy(version, ent->metadata_version);
+
+	if (is_subarray(&version[9])) {
+		char *subarray = strrchr(version, '/');
+		char *name = &version[10];
+
+		if (!subarray)
+			return;
+		*subarray++ = '\0';
+
+		st->container_dev = devname2devnum(name);
+		strncpy(st->subarray, subarray, sizeof(st->subarray));
+	}
+}
+
 void RebuildMap(void)
 {
 	struct mdstat_ent *mdstat = mdstat_read(0, 0);
@@ -337,8 +365,10 @@ void RebuildMap(void)
 			st = guess_super(dfd);
 			if ( st == NULL)
 				ok = -1;
-			else
+			else {
+				set_member_info(st, md);
 				ok = st->ss->load_super(st, dfd, NULL);
+			}
 			close(dfd);
 			if (ok != 0)
 				continue;