mdadm/mdadm-3.0-foreign.patch

--- mdadm-3.0-devel3/Incremental.c.foreign	2009-03-20 17:11:01.000000000 -0400
+++ mdadm-3.0-devel3/Incremental.c	2009-03-20 17:11:39.000000000 -0400
@@ -48,8 +48,10 @@ int Incremental(char *devname, int verbo
 	 * 2/ Find metadata, reject if none appropriate (check
 	 *       version/name from args)
 	 * 3/ Check if there is a match in mdadm.conf
-	 * 3a/ if not, check for homehost match.  If no match, assemble as
-	 *    a 'foreign' array.
+	 * 3a/ Evalutate the quality of match and whether or not we have a
+	 * 	 conf file at all, and make a decision about whether or not
+	 * 	 to allow this array to keep its preferred name based upon 
+	 * 	 that
 	 * 4/ Determine device number.
 	 * - If in mdadm.conf with std name, use that
 	 * - UUID in /dev/md/mdadm.map  use that
@@ -78,7 +80,7 @@ int Incremental(char *devname, int verbo
 	 */
 	struct stat stb;
 	struct mdinfo info;
-	struct mddev_ident_s *array_list, *match;
+	struct mddev_ident_s *array_list, *match, *match_uuid, *match_name;
 	char chosen_name[1024];
 	int rv;
 	struct map_ent *mp, *map = NULL;
@@ -150,24 +152,37 @@ int Incremental(char *devname, int verbo
 
 	array_list = conf_get_ident(NULL);
 	match = NULL;
+	match_uuid = NULL;
+	match_name = NULL;
 	for (; array_list; array_list = array_list->next) {
+		/* Check for matching uuid, then drop through to check and see
+		 * if we also have a matching name, and to catch cases of
+		 * matching names without a corresponding uuid match */
 		if (array_list->uuid_set &&
 		    same_uuid(array_list->uuid, info.uuid, st->ss->swapuuid)
-		    == 0) {
-			if (verbose >= 2 && array_list->devname)
+		    != 0)
+			match_uuid = array_list;
+		else if (array_list->uuid_set && verbose >= 2 &&
+			 array_list->devname)
 				fprintf(stderr, Name
 					": UUID differs from %s.\n",
 					array_list->devname);
-			continue;
-		}
+		/* If we match name now and the entry has a uuid, it *must*
+		 * match.  If we match name, but the entry *doesn't* have
+		 * a uuid set, save it off separately so we can tell if we
+		 * matched uuid, name, or both, and if both, if they were
+		 * the same entry */
 		if (array_list->name[0] &&
-		    strcasecmp(array_list->name, info.name) != 0) {
-			if (verbose >= 2 && array_list->devname)
+		    strcasecmp(array_list->name, info.name) == 0)
+			match_name = array_list;
+		else if (array_list->name[0] && verbose >= 2 &&
+			 array_list->devname)
 				fprintf(stderr, Name
 					": Name differs from %s.\n",
 					array_list->devname);
+		if ((!match_uuid || match == match_uuid) &&
+		    (!match_name || match == match_name))
 			continue;
-		}
 		if (array_list->devices &&
 		    !match_oneof(array_list->devices, devname)) {
 			if (verbose >= 2 && array_list->devname)
@@ -197,7 +212,13 @@ int Incremental(char *devname, int verbo
 		/* FIXME, should I check raid_disks and level too?? */
 
 		if (match) {
-			if (verbose >= 0) {
+			if (match_uuid != match_name) {
+				if (match_uuid->devname)
+					fprintf(stderr, Name ": more than one "
+						"match for %s, using the UUID "
+						"match\n", match_uuid->devname);
+				match = match_uuid;
+			} else if (verbose >= 0) {
 				if (match->devname && array_list->devname)
 					fprintf(stderr, Name
 		   ": we match both %s and %s - cannot decide which to use.\n",
@@ -205,23 +226,54 @@ int Incremental(char *devname, int verbo
 				else
 					fprintf(stderr, Name
 						": multiple lines in mdadm.conf match\n");
+				return 2;
 			}
-			return 2;
 		}
 		match = array_list;
 	}
 
-	/* 3a/ if not, check for homehost match.  If no match, continue
-	 * but don't trust the 'name' in the array. Thus a 'random' minor
-	 * number will be assigned, and the device name will be based
-	 * on that. */
-	if (match)
+	/* 3a/ Decide if we got a good match, two matches, no matches, or a
+	 * likely foreign match.  I dropped the homehost test entirely because
+	 * it didn't seem to add any value whatsoever above and beyond what
+	 * these tests can do. */
+	if (match_uuid == match_name)
+		/* found in conf, both name and uuid match */
 		trustworthy = LOCAL;
-	else if (homehost == NULL ||
-		 st->ss->match_home(st, homehost) != 1)
+	else if (match_uuid && match_name)
+		/* found both a name and a uuid match, but not on the same
+		 * entry, so use a random name and assume UUID match was
+		 * correct but has a bad name just in case the one that
+		 * would match the matching name shows up with both a 
+		 * matching name and a matching UUID */
 		trustworthy = FOREIGN;
-	else
-		trustworthy = LOCAL;
+	else if (!match_uuid && match_name) {
+		/* no uuid match, but name match */
+		if (match_name->uuid_set)
+			/* oops, name that matched had a uuid, it just wasn't
+			 * right, assume there is a local device with both
+			 * a matching name and uuid, so this needs a random
+			 * name */
+			trustworthy = FOREIGN;
+		else
+			/* matched name, and the matching entry in conf file
+			 * didn't include a uuid, and this uuid never showed
+			 * up anywhere else in the conf file, so consider it
+			 * a soft match and allow it...although users should
+			 * *REALLY* include the uuid on array lines in the
+			 * conf file */
+			trustworthy = LOCAL;
+	} else { /* no match at all */
+		if (!conf_exists())
+			/* If we don't even have a conf file, this is foreign,
+			 * but also not likely to conflict with anything
+			 * local, so let it keep its preferred name */
+			trustworthy = LOCAL;
+		else
+			/* We have a conf file, this didn't match any uuids
+			 * or names, so also not likely to conflict, let it
+			 * keep its own name */
+			trustworthy = LOCAL;
+	}
 
 	/* There are three possible sources for 'autof':  command line,
 	 * ARRAY line in mdadm.conf, or CREATE line in mdadm.conf.
--- mdadm-3.0-devel3/mdadm.h.foreign	2009-03-10 01:39:41.000000000 -0400
+++ mdadm-3.0-devel3/mdadm.h	2009-03-20 17:11:01.000000000 -0400
@@ -785,6 +785,7 @@ extern mddev_dev_t conf_get_devs(void);
 extern int conf_test_dev(char *devname);
 extern struct createinfo *conf_get_create_info(void);
 extern void set_conffile(char *file);
+extern int conf_exists(void);
 extern char *conf_get_mailaddr(void);
 extern char *conf_get_mailfrom(void);
 extern char *conf_get_program(void);
--- mdadm-3.0-devel3/config.c.foreign	2009-03-10 01:39:41.000000000 -0400
+++ mdadm-3.0-devel3/config.c	2009-03-20 17:11:01.000000000 -0400
@@ -637,7 +637,7 @@ void homehostline(char *line)
 	}
 }
 
-
+int exists = 0;
 int loaded = 0;
 
 static char *conffile = NULL;
@@ -683,6 +683,7 @@ void load_conffile(void)
 	if (f == NULL)
 		return;
 
+	exists = 1;
 	loaded = 1;
 	while ((line=conf_line(f))) {
 		switch(match_keyword(line)) {
@@ -718,6 +719,13 @@ void load_conffile(void)
 /*    printf("got file\n"); */
 }
 
+int conf_exists(void)
+{
+	if (!loaded)
+		load_conffile();
+	return exists;
+}
+
 char *conf_get_mailaddr(void)
 {
 	load_conffile();