VOP_LEASE

[Alfred Perlstein]

* Sam Leffler <sam at freebsd.org> [080412 12:41] wrote:
> Doug Rabson wrote:
> >
> >On 12 Apr 2008, at 18:03, Kirk McKusick wrote:
> >
> >>>Date: Sat, 12 Apr 2008 02:13:15 -1000 (HST)
> >>>From: Jeff Roberson <jroberson at jroberson.net>
> >>>To: arch at freebsd.org
> >>>Subject: VOP_LEASE
> >>>
> >>>As far as I can tell this has never been used.  Unless someone can 
> >>>show me
> >>>otherwise I'm going to go ahead and remove it.
> >>>
> >>>Thanks,
> >>>Jeff
> >>
> >>VOP_LEASE is used by NQNFS and NFSv4. It notifies them when a file
> >>is modified locally so that they know to update any outstanding
> >>leases (e.g., evict any write lease for the file and do callbacks
> >>for any read leases for the file). Deleting VOP_LEASE would break
> >>NFS big time.
> >
> >I think our NQNFS support might have been removed some time ago - I 
> >can't see any calls to VOP_LEASE in the code right now. Something like 
> >VOP_LEASE would certainly be useful for a hypothetical future NFSv4 
> >server. I believe that samba could use it too for its oplocks feature 
> >which appears to be similar to NQNFS's leases and NFSv4's delegations.
> >
> 
> Note NQNFS is long dead (netbsd removed it also not too long 
> ago--together with VOP_LEASE).  Jeff doesn't say why he wants to remove 
> it but it might be best removed only to return when there's a real 
> consumer of the api.

We have people on the verge of implementing NFSv4, in fact we
have a half-done client right now.  I don't think it makes sense
to remove it as I have stated before.

-Alfred