[PATCH] flock() files even with a permissive share mode.

[J. Bruce Fields]

On Sat, Feb 02, 2019 at 06:26:17PM +0100, Volker Lendecke via samba-technical wrote:
> On Fri, Feb 01, 2019 at 08:38:04PM -0500, Matthew Stickney via samba-technical wrote:
> > I've only just begun poking around the samba code, so apologies if I've
> > missed something obvious (or if this is the wrong list for this sort of
> > question).
> 
> This is exactly right. The problem with this API is -- nobody cares.
> You are the first one in MANY years who has taken a look.
> 
> Whenever I have the chance to meet NFS people, I literally beg for
> their precious time to discuss interoperable locking. We need to at
> least talk about the intended semantics: What does a share mode in SMB
> mean for NFS share reservations, and how do we properly communicate
> that? What about mandatory vs advisory? What about leases/oplocks vs
> delegations? What is a good break mechanism? We need to sort this out
> in user space before we can even start approaching the kernel.
> 
> The NFS people I met do not see this as a priority, nobody ever could
> allocate time.

I'm an NFS person, and yes, time's always a problem, but I'd love to
work on this.

Mainly what I need from SMB folks is really precise documentation of the
semantics expected from the SMB side and/or some tests for those
semantics.

I'm especially interested in lease/delegation work (as I have work to do
in that area anyway).

--b.

> Locking seems to be a topic nobody outside the SMB
> world ever looks at. We need to keep the VFS call in, because I know
> of at least one vendor who has this implemented in his proprietary
> file system. For the rest -- I don't think it matters if we keep it
> in.