-s/^( *locking_type = )1.*$/$1 = 2/m or die;
-s/^( *fallback_to_clustered_locking = ).*$/$1 = 0/m or die;
-s/^( *fallback_to_local_locking = ).*$/$1 = 0/m or die;
+s#^( *filter) = .*#$1 = [ "r|/dev/mapper/xenvg-.*|" ]#m or die;
+s/^( *locking_type) = 1.*$/$1 = 2/m or die;
+s/^( *fallback_to_clustered_locking) = .*$/$1 = 0/m or die;
+s/^( *fallback_to_local_locking) = .*$/$1 = 0/m or die;