Patent ID: 7913050

Claim:
A method for processing a write request at a storage device, comprising: receiving for each fence-able entity of a plurality of fence-able entities, a message that identifies at least one ascendant to which said each fence-able entity is subordinate in a fence-able entity hierarchy of a plurality of fence-able entity hierarchies; in response to receiving the messages, generating and storing relationship data that specifies said plurality of fence-able entity hierarchies; wherein the plurality of fence-able entity hierarchies include a first fence-able entity hierarchy with a first number of hierarchical levels and a second fence-able entity hierarchy with a second number of hierarchical levels that is different than said first number; receiving, at said storage device, a write request that identifies a sender of said write request; the storage device determining if said sender is allowed to write to said storage device by performing: examining said write request to determine an identity of said sender, based on the relationship data, determining whether, within a particular fence-able entity hierarchy of said plurality of fence-able entity hierarchies, the sender is subordinate to any fence-able entity that has been designated as being unable to perform write requests at said storage device, and upon determining that (a) the sender is not subordinate to any fence-able entity that has been designated as being unable to perform write requests at said storage device, and (b) the sender has not been designated as being unable to perform write requests at said storage device, then concluding that said sender is allowed to write to said storage device; and upon determining that said sender is allowed to write to said storage device, performing said write request at said storage device.