File operations with persistent file locking techniques

Abstract

File systems which provide several different and improved locking capabilities. An application on a client workstation communicates through a client driver to a server which interfaces with a metadata database, which contains locking information about the files. Applications perform as normal. The client driver provides lock and unlock requests to the server when a write lock or a read with intent to write lock is required. If only a read lock is considered appropriate, the client driver does not provide a lock request. The server transparently performs read operations and read locking using the metadata database without specific requests from the client driver. When a read with intent to write or write lock is required, the lock ownership is placed with a given expiration time. When the time expires the lock is not automatically released but remains with the particular requesting client driver until another client driver requests it.