linux-base: Where a device has both a UUID and a label, prefer to use UUID

svn path=/dists/sid/linux-2.6/; revision=15487

debian/changelog

@@ -14,6 +14,8 @@ linux-2.6 (2.6.32-11) UNRELEASED; urgency=low
       debconf (Closes: #574987)
     - Report when hdparm.conf or mdadm.conf may need to be updated
       (Closes: #576442)
+    - Where a device has both a UUID and a label, prefer to identify it by
+      UUID, consistent with fresh installations
   * iwlwifi: Fix repeated warnings about tfds_in_queue (Closes: #574526)
   * eeepc-laptop: Disable CPU speed control on 701 and 702 since it can
     cause the system to hang (Closes: #559578)

debian/linux-base.postinst

@@ -1230,9 +1230,12 @@ sub scan_devices {
     }
 
     # Discard all labels and UUIDs(!) that are ambiguous.
+    # Sort each device's IDs in reverse lexical order so that UUIDs are
+    # preferred.
     for my $bdev (keys(%bdev_map)) {
-	@{$bdev_map{$bdev}->{ids}} = grep({ $#{$id_map{$_}} == 0 }
-					  @{$bdev_map{$bdev}->{ids}});
+	@{$bdev_map{$bdev}->{ids}} =
+	    sort({$b cmp $a}
+		 grep({ $#{$id_map{$_}} == 0 } @{$bdev_map{$bdev}->{ids}}));
     }
 
     # Add persistent aliases for CD/DVD/BD drives