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AssigneeInternational Business Machines Corporation
InventorsRobert J. Curran, Roger L. Haskin, Kuei-Yu Wang-Knop, Frank B. Schmuck
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The present invention is directed to a method for controlling file access in a multinode, shared storage, data processing system in which a one set of nodes is capable of acting as metadata controllers and a second set of nodes are tuned for running user applications. By providing two kinds of locks operative at the file level of granularity, a mechanism is produced which permits application programs to also run on their set of metadata controller nodes. One of the locks permits read and write access to existing data blocks but precludes operations such as file deletion or file truncation. The other lock is of lower authority and permits metadata controller nodes, which can provide time limited permissions to the application nodes, to withhold locks which authorize access when requests for access are made from application nodes.
A method for controlling file access in a multinode, shared storage data processing system in which a first set of nodes is capable of acting as metadata controller nodes and in which a second set of nodes has time limited file level access to said shared storage but which do not act as metadata controller nodes for said file, said method of control comprising the steps of:
A multinode, shared storage data processing system in which a first set of nodes is capable of acting as metadata controller nodes and a first node from said first set of nodes so acts to provide access to an individual file in said shared storage, said access being provided so that access occurs from a second node, not within said first set of nodes, which has time limited access to said file but which does not act as a metadata controller for said file, said data processing system including a memory within at least one of said nodes, said memory containing program code for performing the steps of:
A program product comprising a machine readable medium containing program code, for use in a multinode, shared storage data processing system in which a first set of nodes is capable of acting as metadata controller nodes and a first node from said first set of nodes so acts to provide access to an individual file in said shared storage, said access being provided so that access occurs from a second node, not within said first set of nodes, which has time limited access to said file but which does not act as a metadata controller for said file, said data processing system including a memory within at least one of said nodes for performing the steps of:
Dependencies are inferred from the claim text.