diff --git a/core/lib/Drupal/Component/PhpStorage/FileStorage.php b/core/lib/Drupal/Component/PhpStorage/FileStorage.php
index 6853356..f933884 100644
--- a/core/lib/Drupal/Component/PhpStorage/FileStorage.php
+++ b/core/lib/Drupal/Component/PhpStorage/FileStorage.php
@@ -84,20 +84,7 @@ public function writeable() {
    */
   public function deleteAll() {
     if (is_dir($this->directory)) {
-      $iterator = new \RecursiveDirectoryIterator($this->directory);
-      foreach (new \RecursiveIteratorIterator($iterator, \RecursiveIteratorIterator::CHILD_FIRST) as $file) {
-        if (!$iterator->isDot()) {
-          $this->filePreDeleteCallback($file->getPathname());
-          if ($file->isDir()) {
-            rmdir($file->getPathname());
-          }
-          else {
-            unlink($file->getPathname());
-          }
-        }
-      }
-      $this->filePreDeleteCallback($this->directory);
-      return rmdir($this->directory);
+      return $this->deleteRecursive($this->directory);
     }
     else {
       // Return TRUE for non-existent folder, but log that nothing was actually
@@ -107,6 +94,39 @@ public function deleteAll() {
   }
 
   /**
+   * Deletes all files and directories in the specified filepath recursively.
+   *
+   * If the specified path is a directory then the function will call itself
+   * recursively to process the contents. Once the contents have been removed
+   * the directory will also be removed.
+   *
+   * Note that this only deletes visible files with write permission.
+   *
+   * @param string $path
+   *   A string containing either a file or directory path.
+   *
+   * @return boolean
+   *   TRUE for success or if path does not exist, FALSE in the event of an
+   *   error.
+   */
+  protected function deleteRecursive($path) {
+    $this->filePreDeleteCallback($path);
+    if (is_dir($path)) {
+      $dir = dir($path);
+      while (($entry = $dir->read()) !== FALSE) {
+        if ($entry == '.' || $entry == '..') {
+          continue;
+        }
+        $entry_path = $path . '/' . $entry;
+        $this->deleteRecursive($entry_path);
+      }
+      $dir->close();
+      return drupal_rmdir($path);
+    }
+    return unlink($path);
+  }
+
+  /**
    * Ensures files and directories are deletable.
    */
   public function filePreDeleteCallback($path) {