CIFS Unix Extensions and uid/gid/mode

Any opinions on whether there should be a way to mount to Samba (which 
supports the CIFS Unix Extensions by default) but ignore the 
uid/gid/mode (and posix acls) which the server returns?    For cases in 
which the Samba server has different uids than the client, mounts can be 
awkward, eventually we may add a way to load a uid mapping table to help 
with this kind of case, but in the meantime, I have been wondering about 
whether we should allow overrides of a "default uid" or gid or mode even 
when Unix Extensions are negotiated.

Currently the only way to do this with cifs client is to disable the 
Unix Extensions on the client or server (which also disables posix 
locking, the extended posix statfs and unix mknod).

Currently,  uid, gid, and file_mode and dir_mode are ignored when the 
unix extensions are negotiated.

Should another mount parm be added (what would its name be?) that would 
cause those parms to be accepted rather than ignored? should all four be 
required to be filled in?   Alternatively, we could allow uid, gid, 
file_mode and dir_mode to be accepted on mounts with the Unix extensions 
- but this would silently change behavior of existing clients and would 
make it harder for the rare case of  the user who wants to use the 
server's uid/gid/mode if Unix Extensions are on - but if they are off on 
the server wants to use the default uid/gid/mode specified on mount.