Patent ID: 7640582

Claim:
A method of operating a cluster of computer system nodes sharing direct read/write access to filesystems administered by at least one trusted metadata server node on storage devices connected to the computer system nodes via a storage area network, comprising: assigning a mandatory access control label, including a first indication of sensitivity and integrity, as an extended attribute of each filesystem object administered by the at least one trusted metadata server node regardless of whether required by a client node creating the filesystem object; assigning a second indication of sensitivity and integrity to each node having access to the filesystem; and permitting access to the filesystem object by any client node only if the second indication of sensitivity and integrity assigned thereto meets criteria defined by the first indication of sensitivity and integrity in the mandatory access control label of the filesystem object; wherein said assigning uses a default mandatory access control label if a filesystem mandatory access control label is not assigned to the filesystem and a networking mandatory access control label is not assigned to the client node.