[PATCH] MD - Remove concept of 'spare' drive for multipath.

Remove concept of 'spare' drive for multipath.

Multipath now treats all working devices as
active and does io to to first working one.

include/linux/raid/multipath.h

@@ -13,7 +13,6 @@ struct multipath_info {
 	 * State bits:
 	 */
 	int		operational;
-	int		spare;
 
 	int		used_slot;
 };