Index: library/Zend/Cache/Backend/File.php
===================================================================
--- library/Zend/Cache/Backend/File.php	(revision 23890)
+++ library/Zend/Cache/Backend/File.php	(working copy)
@@ -722,8 +722,8 @@
             if ((is_dir($file)) and ($this->_options['hashed_directory_level']>0)) {
                 // Recursive call
                 $result = $this->_clean($file . DIRECTORY_SEPARATOR, $mode, $tags) && $result;
-                if ($mode=='all') {
-                    // if mode=='all', we try to drop the structure too
+                if ($mode == Zend_Cache::CLEANING_MODE_ALL) {
+                    // we try to drop the structure too
                     @rmdir($file);
                 }
             }