Release Celerra File System Capacity

Is there either a scheduled task or a manual method for "releasing" capacity within a Celerra file system? In this case, an iSCSI attached LUN filled up which in turn caused the file system to fill up. A bunch of stuff was deleted in the LUN, but the file system is still full. I haven't been able to find any documentation that speaks to this specifically. Let me know if you need any other details. Thanks