merge from 5.1 to 5.5

sql/log.cc

@@ -4863,12 +4863,18 @@ MYSQL_BIN_LOG::flush_and_set_pending_rows_event(THD *thd,
     /*
       Write pending event to the cache.
     */
+    DBUG_EXECUTE_IF("simulate_disk_full_at_flush_pending",
+                    {DBUG_SET("+d,simulate_file_write_error");});
     if (pending->write(file))
     {
       set_write_error(thd, is_transactional);
       if (check_write_error(thd) && cache_data &&
           stmt_has_updated_non_trans_table(thd))
         cache_data->set_incident();
+      delete pending;
+      cache_data->set_pending(NULL);
+      DBUG_EXECUTE_IF("simulate_disk_full_at_flush_pending",
+                      {DBUG_SET("-d,simulate_file_write_error");});
       DBUG_RETURN(1);
     }