Issues with Linux kernel oplocks

[Jeremy Allison]

On Tue, Jul 23, 2013 at 04:32:16PM -0400, J. Bruce Fields wrote:
> 
> Sure, but...
> 
> > Neither process has to be privileged, neither
> > process has to have changed uids.
> > 
> > For leases to work this condition:
> > 
> > "the real or effective user ID of the sending process must equal
> > the real or saved set-user-ID of the target process."
> > 
> > cannot be correct. Else you could only break leases between
> > processes who are owned by the same uid - or from a privileged
> > opener.
> 
> ... you're confusing the lease-breaker and the lease-setter.
> 
> Note in the first quote above, "where the sending process is the one
> that employs F_SETOWN".  (Or equivalently, I think, F_SETLEASE.)

Ok then I'm really confused. Samba always does
the lease set as the same uid as the open, we
never change uids between the open and the
setting of the kernel oplock.

What is the problem I'm missing here ? (Sorry,
I'm being spectaularly dense here I know :-).

Jeremy.