Preliminary -As support for container member arrays

Given an mdadm.conf like the following allow /dev/imsm and /dev/md/r1 to be
created by "mdadm -As".

DEVICES partitions 
ARRAY /dev/imsm metadata=imsm auto=md UUID=b98f5dbe-aa859e7b-0e369b89-a80986d4 
ARRAY /dev/md/r1 container=/dev/imsm member=0 auto=mdp UUID=3538e39c-b397c2e9-1aa031f9-2bc0eca4 
   spares=1

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

Assemble.c

@@ -181,6 +181,52 @@ int Assemble(struct supertype *st, char *mddev, int mdfd,
 			mddev ? mddev : "further assembly");
 		return 1;
 	}
+
+	/* if the configuration specifies a container then we use that to
+	 * determine the devices and retrieve the array configuration
+	 */
+#ifndef MDASSEMBLE
+	if (ident->container && ident->member) {
+		int cfd = open(ident->container, O_RDWR);
+		struct mdinfo *mdi;
+		struct supertype container;
+
+		if (verbose>0)
+			fprintf(stderr, Name ": looking to assemble member array %s"
+				" inside container %s\n", ident->member, ident->container);
+		if (cfd < 0) {
+			if (verbose>0)
+				fprintf(stderr, Name ": unable to open container %s: %s\n",
+					ident->container, strerror(errno));
+			return 1;
+		}
+
+		mdi = sysfs_read(cfd, fd2devnum(cfd), GET_VERSION);
+		if (!mdi) {
+			close(cfd);
+			if (verbose>0)
+				fprintf(stderr, Name ": unable to read container %s\n",
+					ident->container);
+			return 1;
+		}
+		container.ss = find_metadata_methods(mdi->text_version);
+		sysfs_free(mdi);
+		if (!container.ss) {
+			close(cfd);
+			fprintf(stderr, Name ": %s uses unknown metadata: %s\n",
+				ident->container, mdi->text_version);
+			return 1;
+		}
+		if (container.ss->load_super(&container, cfd, ident->container)) {
+			fprintf(stderr, Name ": Cannot load metadata for container %s\n",
+				ident->container);
+			return 1;
+		}
+
+		return Incremental_container(&container, ident->container,
+					     verbose, runstop, ident->autof);
+	}
+#endif
 	if (devlist == NULL)
 		devlist = conf_get_devs();
 	else if (mdfd >= 0)

Incremental.c

@@ -827,6 +827,9 @@ int Incremental_container(struct supertype *st, char *devname, int verbose,
 					continue;
 				if (strcmp(array_list->member, sub) != 0)
 					continue;
+				if (array_list->uuid_set &&
+				    !same_uuid(ra->uuid, array_list->uuid, st->ss->swapuuid))
+					continue;
 				fd = open(array_list->container, O_RDONLY);
 				if (fd < 0)
 					continue;
@@ -841,6 +844,9 @@ int Incremental_container(struct supertype *st, char *devname, int verbose,
 				free(dn);
 				/* we have a match */
 				match = array_list;
+				if (verbose>0)
+					fprintf(stderr, Name ": match found for member %s\n",
+						array_list->member);
 				break;
 			}
 		}

config.c

@@ -434,6 +434,8 @@ void arrayline(char *line)
 	mis.bitmap_fd = -1;
 	mis.bitmap_file = NULL;
 	mis.name[0] = 0;
+	mis.container = NULL;
+	mis.member = NULL;
 
 	for (w=dl_next(line); w!=line; w=dl_next(w)) {
 		if (w[0] == '/') {

mdadm.h

@@ -783,6 +783,7 @@ extern unsigned long long calc_array_size(int level, int raid_disks, int layout,
 				   int chunksize, unsigned long long devsize);
 extern int flush_metadata_updates(struct supertype *st);
 extern void append_metadata_update(struct supertype *st, void *buf, int len);
+extern struct superswitch *find_metadata_methods(char *vers);
 
 extern int add_disk(int mdfd, struct supertype *st,
 		    struct mdinfo *sra, struct mdinfo *info);

mdmon.c

@@ -92,15 +92,6 @@ int clone_monitor(struct supertype *container)
 	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;
-}
-
 
 int make_pidfile(char *devname, int o_excl)
 {

util.c

@@ -1278,6 +1278,15 @@ void append_metadata_update(struct supertype *st, void *buf, int len)
 	*st->update_tail = mu;
 	st->update_tail = &mu->next;
 }
+
+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;
+}
 #endif /* MDASSEMBLE */
 
 #ifdef __TINYC__