diff -r 5e7a0fedabdf -r 877f952ae2bd web/lib/Zend/Cache/Backend/TwoLevels.php
--- a/web/lib/Zend/Cache/Backend/TwoLevels.php	Thu Mar 21 17:31:31 2013 +0100
+++ b/web/lib/Zend/Cache/Backend/TwoLevels.php	Thu Mar 21 19:50:53 2013 +0100
@@ -15,9 +15,9 @@
  * @category   Zend
  * @package    Zend_Cache
  * @subpackage Zend_Cache_Backend
- * @copyright  Copyright (c) 2005-2010 Zend Technologies USA Inc. (http://www.zend.com)
+ * @copyright  Copyright (c) 2005-2012 Zend Technologies USA Inc. (http://www.zend.com)
  * @license    http://framework.zend.com/license/new-bsd     New BSD License
- * @version    $Id: TwoLevels.php 22736 2010-07-30 16:25:54Z andyfowler $
+ * @version    $Id: TwoLevels.php 24593 2012-01-05 20:35:02Z matthew $
  */
 
 
@@ -35,7 +35,7 @@
 /**
  * @package    Zend_Cache
  * @subpackage Zend_Cache_Backend
- * @copyright  Copyright (c) 2005-2010 Zend Technologies USA Inc. (http://www.zend.com)
+ * @copyright  Copyright (c) 2005-2012 Zend Technologies USA Inc. (http://www.zend.com)
  * @license    http://framework.zend.com/license/new-bsd     New BSD License
  */
 
@@ -383,7 +383,6 @@
         return $this->_slowBackend->getIdsMatchingAnyTags($tags);
     }
 
-
     /**
      * Return the filling percentage of the backend storage
      *
@@ -481,18 +480,19 @@
      */
     private function _getFastLifetime($lifetime, $priority, $maxLifetime = null)
     {
-        if ($lifetime === null) {
-            // if lifetime is null, we have an infinite lifetime
+        if ($lifetime <= 0) {
+            // if no lifetime, we have an infinite lifetime
             // we need to use arbitrary lifetimes
             $fastLifetime = (int) (2592000 / (11 - $priority));
         } else {
-            $fastLifetime = (int) ($lifetime / (11 - $priority));
+            // prevent computed infinite lifetime (0) by ceil
+            $fastLifetime = (int) ceil($lifetime / (11 - $priority));
         }
-        if (($maxLifetime !== null) && ($maxLifetime >= 0)) {
-            if ($fastLifetime > $maxLifetime) {
-                return $maxLifetime;
-            }
+
+        if ($maxLifetime >= 0 && $fastLifetime > $maxLifetime) {
+            return $maxLifetime;
         }
+
         return $fastLifetime;
     }