+ locallease This option is rarely needed. Fcntl F_SETLEASE is
+ used by some applications such as Samba and NFSv4 server to
+ check to see whether a file is cacheable. CIFS has no way
+ to explicitly request a lease, but can check whether a file
+ is cacheable (oplocked). Unfortunately, even if a file
+ is not oplocked, it could still be cacheable (ie cifs client
+ could grant fcntl leases if no other local processes are using
+ the file) for cases for example such as when the server does not
+ support oplocks and the user is sure that the only updates to
+ the file will be from this client. Specifying this mount option
+ will allow the cifs client to check for leases (only) locally
+ for files which are not oplocked instead of denying leases
+ in that case. (EXPERIMENTAL)