diff --git a/lib/private/Files/Storage/Local.php b/lib/private/Files/Storage/Local.php
index 0ef58698623a1..9e194931e6375 100644
--- a/lib/private/Files/Storage/Local.php
+++ b/lib/private/Files/Storage/Local.php
@@ -217,7 +217,7 @@ public function filetype($path) {
 	}
 
 	public function filesize($path) {
-		if ($this->is_dir($path)) {
+		if (!$this->is_file($path)) {
 			return 0;
 		}
 		$fullPath = $this->getSourcePath($path);