Persisting Mutex Lock Data To Enhance Failover Handling By Storage Controllers

A storage controller of a data storage system, comprising:

• one or more memory devices;
• one or more processors operatively coupled with the one or more memory devices;
• and
• program instructions stored on the one or more memory devices that, when read and executed by
• the one or more processors, direct the storage controller to at least:
• in response to a migration of a logical interface from a partner storage controller of the data storage system to the storage controller, obtain lease lock data from a storage aggregate, wherein the partner storage controller persisted the lease lock data to the storage aggregate before the migration;
• receive an I/O request from a client, wherein the I/O request is associated with at least a portion of a file in the storage aggregate;
• determine, based on the lease lock data, that the partner storage controller had not given a lease lock to any other client with respect to at least the portion of the file;
• and
• responsively execute the I/O request.

A data storage system, comprising:

• a storage aggregate;
• a first storage controller configured to persist lease lock data to the storage aggregate;
• and
• a second storage controller configured to:
• in response to a failover of the first storage controller to the second storage controller, obtain the lease lock data from the storage aggregate;
• and
• immediately process incoming I/O requests from a client when the lease lock data indicates that the client owns a lock on the at least a portion of a file or when the lease lock data indicates that there is no current lock on the file.