libmultipath: simplify dm_get_name()

dm_get_name() should just return the device-mapper table
name corresponding to a given uuid. Happily the uuid is
another primary key in the device-mapper hash table, so
we can just use it directly and do not have to loop over
all existing tables.

Signed-off-by: Hannes Reinecke <hare@suse.de>

diff --git a/libmultipath/devmapper.c b/libmultipath/devmapper.c
index 333659b..fb69ee8 100644 (file)
--- a/libmultipath/devmapper.c
+++ b/libmultipath/devmapper.c
@@ -777,35 +777,49 @@ out:
        return r;
 }
 
-extern int
-dm_get_name(char *uuid, char *name)
+extern char *
+dm_get_name(char *uuid)
 {
-       vector vec;
-       struct multipath *mpp;
-       int i, rc = 0;
-
-       vec = vector_alloc();
+       struct dm_task *dmt;
+       struct dm_info info;
+       char *prefixed_uuid, *name = NULL;
+       const char *nametmp;
 
-       if (!vec)
-               return 0;
+       dmt = dm_task_create(DM_DEVICE_INFO);
+       if (!dmt)
+               return NULL;
 
-       if (dm_get_maps(vec)) {
-               goto out;
+       prefixed_uuid = MALLOC(UUID_PREFIX_LEN + strlen(uuid) + 1);
+       if (!prefixed_uuid) {
+               condlog(0, "cannot create prefixed uuid : %s\n",
+                       strerror(errno));
+               goto freeout;
        }
+       sprintf(prefixed_uuid, UUID_PREFIX "%s", uuid);
+       if (!dm_task_set_uuid(dmt, prefixed_uuid))
+               goto freeout;
 
-       vector_foreach_slot(vec, mpp, i) {
-               if (!strcmp(uuid, mpp->wwid)) {
-                       strcpy(name, mpp->alias);
-                       rc=1;
-                       break;
-               }
-       }
-out:
-       vector_foreach_slot(vec, mpp, i) {
-               free_multipath(mpp, KEEP_PATHS);
+       if (!dm_task_run(dmt))
+               goto freeout;
+
+       if (!dm_task_get_info(dmt, &info) || !info.exists)
+               goto freeout;
+
+       nametmp = dm_task_get_name(dmt);
+       if (nametmp && strlen(nametmp)) {
+               name = MALLOC(strlen(nametmp) + 1);
+               if (name)
+                       strcpy(name, nametmp);
+       } else {
+               condlog(2, "%s: no device-mapper name found", uuid);
        }
-       vector_free(vec);
-       return rc;
+
+freeout:
+       if (prefixed_uuid)
+               FREE(prefixed_uuid);
+       dm_task_destroy(dmt);
+
+       return name;
 }
 
 int

diff --git a/libmultipath/devmapper.h b/libmultipath/devmapper.h
index f3ffeaa..6c22bf3 100644 (file)
--- a/libmultipath/devmapper.h
+++ b/libmultipath/devmapper.h
@@ -37,6 +37,6 @@ int dm_remove_partmaps (const char * mapname, int need_sync);
 int dm_get_uuid(char *name, char *uuid);
 int dm_get_info (char * mapname, struct dm_info ** dmi);
 int dm_rename (char * old, char * new);
-int dm_get_name(char * uuid, char * name);
+char * dm_get_name(char * uuid);
 
 #endif /* _DEVMAPPER_H */

diff --git a/libmultipath/propsel.c b/libmultipath/propsel.c
index 3074ce1..9944675 100644 (file)
--- a/libmultipath/propsel.c
+++ b/libmultipath/propsel.c
@@ -247,15 +247,8 @@ select_alias (struct multipath * mp)
                        mp->alias = get_user_friendly_alias(mp->wwid,
                                        conf->bindings_file, mp->alias_prefix);
                }
-               if (mp->alias == NULL){
-                       char *alias;
-                       if ((alias = MALLOC(WWID_SIZE)) != NULL){
-                               if (dm_get_name(mp->wwid, alias) == 1)
-                                       mp->alias = alias;
-                               else
-                                       FREE(alias);
-                       }
-               }
+               if (mp->alias == NULL)
+                       mp->alias = dm_get_name(mp->wwid);
                if (mp->alias == NULL)
                        mp->alias = STRDUP(mp->wwid);
        }

diff --git a/libmultipath/structs_vec.c b/libmultipath/structs_vec.c
index 51c41e8..c526a70 100644 (file)
--- a/libmultipath/structs_vec.c
+++ b/libmultipath/structs_vec.c
@@ -337,15 +337,11 @@ retry:
        if (update_multipath_strings(mpp, vecs->pathvec)) {
                char *new_alias;
 
-               new_alias = MALLOC(WWID_SIZE);
-               if (!new_alias) {
-                       condlog(0, "%s: failed to allocate alias", mpp->alias);
-                       goto out;
-               }
                /*
                 * detect an external rename of the multipath device
                 */
-               if (dm_get_name(mpp->wwid, new_alias)) {
+               new_alias = dm_get_name(mpp->wwid);
+               if (new_alias) {
                        condlog(3, "%s multipath mapped device name has "
                                "changed from %s to %s", mpp->wwid,
                                mpp->alias, new_alias);