php upload errors are written to log

apps/files/ajax/upload.php

@@ -88,7 +88,9 @@ foreach ($_FILES['files']['error'] as $error) {
 			UPLOAD_ERR_NO_TMP_DIR => $l->t('Missing a temporary folder'),
 			UPLOAD_ERR_CANT_WRITE => $l->t('Failed to write to disk'),
 		);
-		OCP\JSON::error(array('data' => array_merge(array('message' => $errors[$error]), $storageStats)));
+		$errorMessage = $errors[$error];
+		\OC::$server->getLogger()->alert("Upload error: $error - $errorMessage", array('app' => 'files'));
+		OCP\JSON::error(array('data' => array_merge(array('message' => $errorMessage), $storageStats)));
 		exit();
 	}
 }