dm_resume: dm_table_unplug_all() was being called on md->map, rather
than the 'map' we carefully took a reference on earlier on in the
function.
--- diff/drivers/md/dm.c	2004-04-07 11:32:25.212680672 +0100
+++ source/drivers/md/dm.c	2004-04-07 11:32:27.087395672 +0100
@@ -974,7 +974,7 @@ int dm_resume(struct mapped_device *md)
 	def = bio_list_get(&md->deferred);
 	__flush_deferred_io(md, def);
 	up_write(&md->lock);
-	dm_table_unplug_all(md->map);
+	dm_table_unplug_all(map);
 	dm_table_put(map);
 
 	return 0;