Missing protocol features that could help Linux

[Steve French]

On Fri, Apr 19, 2024 at 10:55 AM Jeremy Allison <jra at samba.org> wrote:

> On Fri, Apr 19, 2024 at 01:40:34PM +1200, Andrew Bartlett wrote:
> >POSIX <-> POSIX locking over SMB is something I have a client trying to
> >get working with SMB3.
> >
> >They have a use case where, as I understand it so far, the mapping of
> >POSIX fcntl() read and write locks to SMB locks isn't 1-1, because they
> >expect advisory locks, but SMB locks are mandatory as far as I read
> >it.
> >
> >They use cifs.ko and Samba, so it isn't about working with Windows, it
> >is about running Libreoffice on LInux against Samba.
>
> That's not going to work the way LibreOffice on Linux expects,
> until we fully expose POSIX locking semantics.
>
> It's the range semantics that will probably break them.
>
> POSIX locks can be split/merged/overlapped. Windows locks
> must be distinct. Currently over SMB3 we only expose Windows
> locks.
>

For a surprising number of Linux apps mounting with "nobrl" (which only
enforces byte range locks locally, and thus POSIX style not Windows
style) is fine for SMB3.1.1 mounts.
-- 
Thanks,

Steve