diff --git a/PVE/Storage/BTRFSPlugin.pm b/PVE/Storage/BTRFSPlugin.pm
index dbc1244..b30000b 100644
--- a/PVE/Storage/BTRFSPlugin.pm
+++ b/PVE/Storage/BTRFSPlugin.pm
@@ -410,7 +410,7 @@ sub free_image {
 	$class->parse_volname($volname);
 
     if (!defined($format) || ($format ne 'subvol' && $format ne 'raw')) {
-	return PVE::Storage::DirPlugin->free_image($storeid, $scfg, $volname, $isBase, $_format);
+	return $class->SUPER::free_image($storeid, $scfg, $volname, $isBase, $_format);
     }
 
     my $path = $class->filesystem_path($scfg, $volname);