diff --git a/httprl.module b/httprl.module
index a279e01..02a3345 100644
--- a/httprl.module
+++ b/httprl.module
@@ -6,6 +6,16 @@
  */
 
 /**
+ * Default maximum number of seconds a single request call may take.
+ */
+define('HTTPRL_TIMEOUT', 30.0);
+
+/**
+ * Default maximum number of seconds a function call may take.
+ */
+define('HTTPRL_GLOBAL_TIMEOUT', 120.0);
+
+/**
  * Error code indicating that the request made by httprl_request() exceeded
  * the maximum allowed redirects without reaching the final target.
  */
@@ -268,14 +278,14 @@ function httprl_set_default_options(&$options) {
     'method' => 'GET',
     'data' => NULL,
     'max_redirects' => 3,
-    'timeout' => 30.0,
+    'timeout' => HTTPRL_TIMEOUT,
     'context' => NULL,
     'blocking' => TRUE,
     'version' => '1.0',
     'referrer' => FALSE,
     'domain_connections' => 8,
     'global_connections' => 128,
-    'global_timeout' => 120.0,
+    'global_timeout' => HTTPRL_GLOBAL_TIMEOUT,
     'chunk_size_read' => 32768,
     'chunk_size_write' => 1024,
     'async_connect' => TRUE,
@@ -560,9 +570,8 @@ function httprl_build_request_string($uri, $options) {
  *   - global_connections: Maximum number of simultaneous connections that can
  *     be open on the server. Default is 128.
  *   - global_timeout: A float representing the maximum number of seconds the
- *     function call may take. The default is 30 seconds. If a timeout occurs,
- *     the error code is set to the HTTPRL_FUNCTION_TIMEOUT constant. Default is
- *     120 seconds.
+ *     function call may take. If a timeout occurs,the error code is set to the
+ *     HTTPRL_FUNCTION_TIMEOUT constant. Default is 120 seconds.
  *   - chunk_size_write: max size of what will be written in fwrite().
  *   - chunk_size_read: max size of what will be read from fread().
  *   - async_connect: default is TRUE. FALSE may give more info on errors but is
@@ -1503,12 +1512,23 @@ function httprl_queue_background_callback(&$args, &$result = NULL) {
     $callback_options['function'] = '';
   }
 
+  // Get the maximum amount of time this could take.
+  $times = array(HTTPRL_TIMEOUT, HTTPRL_GLOBAL_TIMEOUT);
+  if (isset($callback_options['options']['timeout'])) {
+    $times[] = $callback_options['options']['timeout'];
+  }
+  if (isset($callback_options['options']['global_timeout'])) {
+    $times[] = $callback_options['options']['global_timeout'];
+  }
+
   // Acquire lock for this run.
   $locked = FALSE;
-  $counter = 0;
-  while (!$locked && $counter < 20) {
+  $lock_counter = 0;
+  while (!$locked && $lock_counter < 20) {
     $id = 'httprl_' . hash('sha512', mt_rand() . time());
-    $locked = lock_acquire($id);
+    // Set lock to maximum amount of time.
+    $locked = lock_acquire($id, max($times));
+    $lock_counter++;
   }
 
   // Make sure lock exists after this process is dead.
@@ -1562,7 +1582,7 @@ function httprl_queue_background_callback(&$args, &$result = NULL) {
     $options += $callback_options['options'];
   }
   // Send Request.
-  httprl_request($url, $options);
+  return httprl_request($url, $options);
 }
 
 /**