Patent ID: 6389420
Filing Date: 2002-05-14
Classification: G06F,Y10S

Abstract:
In a data storage network in which file locks and file metadata are distributed from at least one file manager to network clients to permit the network clients to share access to file data in data storage, a method for permitting the file manager to grant a second lock upon the file data without necessarily receiving notification from a client that it has relinquished a first lock on the file data while ensuring that conflicting locks are never granted, said method comprising the steps of:a) a client setting the beginning of a first period of time over which the client may access the file data once the first lock on the file data has been granted by the file manager, and the client sending a lock request to the file manager for obtaining the first lock on the file data; b) the file manager receiving the lock request from the client, and responding by setting the beginning of a second period of time such that the first period of time is certain to have expired once the second period of time has expired, and granting the first lock upon the file data to the client, and transmitting a lock grant message to the client, and c) the client receiving the lock grant message, and accessing the file data so long as the client's access to the file data will be completed by expiration of the first period of time, whereby the file manager is free to grant a second lock upon the file data after expiration of the second period of time without conflict between the first lock upon the file data and the second lock upon the file data.