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

[Chuck Lever <chuck.lever@oracle.com>]

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.


-- 
Chuck Lever