Re: [PATCH v2] nfs: add dummy definition for nfsd_file

[Mike Snitzer <snitzer@kernel.org>]

On Wed, Apr 23, 2025 at 07:09:40PM +1000, NeilBrown wrote:
> On Wed, 23 Apr 2025, Vincent Mailhol wrote:
> > On 23/04/2025 at 09:32, NeilBrown wrote:
> > > On Wed, 23 Apr 2025, Pali Rohár wrote:
> > >> On Wednesday 23 April 2025 07:54:40 NeilBrown wrote:
> > >>> On Wed, 23 Apr 2025, Pali Rohár wrote:
> > 
> > (...)
> > 
> > >>> Actually I do object to this fix (though I've been busy and hadn't had
> > >>> much change to look at it properly).
> > >>> The fix is ugly.  At the very least it should be wrapping in an 
> > >>>    #if  GCC_VERSION  < whatever
> > 
> > I acknowledge that the fix is a bit ugly, but Mike is the only one who
> > has proposed a solution so far.
> 
> FYI here is my current patch which fixes this problem and a few other
> problems, but doesn't fix everything I (think I) have found, and may
> introduce some problems because some of the interactions are subtle and
> need careful review.
> 
> Once I'm confident of it I hope to break it up into individual patches
> and submit.

Thanks for working through it (and sorry for the troubles...).

This was where we last discussed the need for my hack (I actually
thought it was older RCU implementation in 5.15 that was the issue):
https://lore.kernel.org/all/Zsyhco1OrOI_uSbd@kernel.org/
(somehow it morphed into blaming vintage compilers, e.g. RHEL8's gcc
8.5 or whatever).

We have stable@ kernels to be concerned about.  But hopefully you
carry forward with splitting up the patches like you've planned, they
all make sense and they all get marked for stable@ (6.14+).  Saves the
make-work of effectively implementing the fixes twice (purely for
stable's benefit, by needing to pull your subtle rcu race fixes to the
front).

Thanks,
Mike