Lock elevation in a distributed file storage system

摘要

A client requests access to a resource (e.g., a file) via a node of a storage system. The resource is stored in a directory structure. A directory in the directory structure that includes the resource and that does not have any locks that conflict with the requested access to the resource is identified and selected. A revocable access privilege (e.g., a lock) on the selected directory is awarded to the node accessed by the client, and a directory-to-node association is established. Another association between the requested resource and the node is also established. If there is a subsequent request for the resource or for another resource within that directory, then a revoke notice for the directory access privilege is sent to the node.

主权项

1. A method, comprising:
receiving first information that indicates a first client is requesting access to a first resource via a first node of a storage system comprising a plurality of nodes, wherein said first resource is stored in a directory structure comprising a hierarchy of directories, wherein said first information comprises a fully qualified file name, and wherein second information associating said first resource with said first node is stored on a node of said storage system that is identified by hashing said file name; identifying a first directory in said hierarchy that includes said first resource and that has no locks associated therewith that conflict with said access to said first resource; associating a first lock with said first directory and granting said first lock to said first node, and associating said first resource with said first node; receiving third information that indicates a second client is requesting access to a second resource via a second node of said plurality of nodes, wherein said second resource is stored within said first directory; and revoking said first lock and associating a second lock with said first directory and granting said second lock to said first node accessed by said first client, wherein said second lock has a demoted privilege for said first directory relative to said first lock.