Re: [PATCH v4 3/3] FSD: Fix NFS server hang when there are multiple layout conflicts

[Jeff Layton <jlayton@kernel.org>]

On Wed, 2025-11-19 at 09:09 -0500, Chuck Lever wrote:
> On 11/19/25 5:05 AM, Christoph Hellwig wrote:
> > On Mon, Nov 17, 2025 at 11:40:22AM -0800, Dai Ngo wrote:
> > > > If a .fence_client callback is optional for a layout to provide,
> > > > timeouts for such layout types won't trigger any fencing action. I'm not
> > > > certain yet that's good behavior.
> > > 
> > > Some layout implementation is in experimental state such as block
> > > layout and should not be used in production environment. I don't
> > > know what should we do for that case. Does adding a trace point to
> > > warn the user sufficient?
> > 
> > The block layout isn't really experimental, but really a broken protocol
> > because there is no way to even fence a client except when there is
> > a side channel mapping between the client identities for NFS and the
> > storage protocol.
> 
> Is the protocol broken, or just incomplete, assuming that other
> (unspecified) protocols are necessary to be provided?
> 
> 
> > I'd be all in favour of deprecating the support ASAP and then removing
> > it aggressively.
> If we can say with some certainty that there are no users of the pNFS
> block layout type, and there is no way of addressing the fencing issue,
> then I'm willing to consider removing it.
> 

ACK on dropping it from my standpoint. I've also never seen a block
layout setup in the wild.
-- 
Jeff Layton <jlayton@kernel.org>