Re: Status of delegations feature in NFSv4 client

On Thu, Jun 18, 2026 at 12:44 AM Anna Schumaker <[email protected]> wrote:
>
> Hi Shyam,
>
> On Mon, Jun 15, 2026, at 11:55 PM, Shyam Prasad N wrote:
> > Hi Trond,
> >
> > I wanted to understand if the file delegations feature on the NFSv4
> > client is stable enough on Linux to support it in production
> > environments? It looks like this feature has been around on the client
> > for a really long time now. We tried running some workloads and file
> > delegations offer really good perf benefits.
>
> Like you've said above, file delegations have been around for a long time
> and I would expect them to be stable for production environments.
>
> >
> > At the same time, I'd like to understand about the stability of
> > directory delegations feature on NFS (I understand that this is much
> > newer and only a part of NFSv4.2?). If there are gaps that exist
> > today, please let me know. I'd be interested to submit patches to fix
> > those issues.
>
> Directory delegations are still fairly new, and are used with NFS v4.1
> and v4.2. We have recallable directory delegations as of Linux 6.19. Work
> is underway for supporting the CB_NOTIFY callback, which will hopefully
> be upstream soon (I have patches written for client support, but I need
> to find time to clean them up a bit more before posting them).
>
> I hope this helps!
> Anna
>
> >
> > --
> > Regards,
> > Shyam

Hi Anna,

Thanks for the reply. These answers definitely helped!

-- 
Regards,
Shyam