a system and method for managing access to assets in a distributed data storage system includes requesting , from a client computer , a semi - preemptible access lock from a server computer . the semi - preemptible lock , if granted , is held by the client computer as long as the server does not demand it back , with the client computer granting open instances under non - preemptible file locks for the asset to which the locks pertain as long as the client computer holds the semi - preemptible lock . when another client computer requests the semi - preemptible lock , the server can demand the lock from the holding client , which relinquishes the lock if no open instances are protected by the lock . otherwise , the holding client computer first attempts to downgrade its lock to meet the request , and if compatibility is not achieved thereby , the holding client refuses to relinquish the lock .