[linux-cifs-client] Mapping fcntl remotely to Samba servers

[Steve French]

Of the fcntls, it only looks like the three Linux specific ones would
need to be handled by the cifs client and sent to Samba (after calling
generic_file_fcntl - the kernel fcntl handler - so that the local
notification works even if the cifs call to the server ends up getting
a bad return code from the server):

	F_NOTIFY, F_GETLEASE, F_SETLEASE

Is there a good argument to override the kernels default handling of the
lock fcntls (since these presumably make their way eventually to the
filesystem client anyway)? or F_GETOWN/F_SETOWN? 

Currently the NFS client overrides fcntl only for F_SETFL in order to
check for the invalid combination of O_APPEND and O_DIRECT (which NFS
can not handle), but I suspect that there are other CIFS cases in which 
it makes sense to override the default fcntl handling (ie of the client
kernel) on cifs files/directories.

This is going to be a good chance to test some less well used part of
the Samba cifs support (the notification smbs)