Byte range file locking is supported as part of the NFSv4.1 protocol. The file locking support is structured so that an RPC callback mechanism is not required. This is a departure from the NFSv3 version of the NFS file locking protocol, Network Lock Manager (NLM).
You can list byte range locks on any given file path and release them. For details, see Listing and Releasing NFS Locks.
Article is closed for comments.