Distributed file systems use file lock mechanism to ensure consistency when the shared data are accessed by multiple nodes. In this paper, using the feature of distributed systems that the same file would be accessed frequently and the advantage of high concurrency of range lock, the semi-preemptible range lock for pNFS is proposed. Clients locally cache the finer-grained locks for ranges of files they hold. Clients retain or cache range locks even without the file instances. When an access lock is cached, a client answers some requests without a server message, improving performance by exploiting locality. Simulation results indicate that the proposed locking mechanism can effectively increase concurrency and decrease the communication cost of pNFS.
