Re: NFS stuck in nfs_lookup_revalidate

[Trond Myklebust <trondmy@kernel.org>]

On Fri, 2025-07-18 at 22:19 +0000, Lukáš Hejtmánek wrote:
> Hello,
> 
> > On 4. 6. 2025, at 21:11, Zdenek Salvet <salvet@ics.muni.cz> wrote:
> > 
> > On Thu, Jun 05, 2025 at 12:00:44AM +0530, Santosh Pradhan wrote:
> > > I am not sure but I vaguely remember that there was some similar
> > > issue and
> > > Neil introduced store_release_wake_up() which puts a full
> > > barrier  smp_mb()
> > > before calling wake_up_var().
> > > 
> > > index d0e0b435a843..e754e3e478a5 100644
> > > --- a/fs/nfs/dir.c
> > > +++ b/fs/nfs/dir.c
> > > @@ -1830,6 +1830,7 @@ static void unblock_revalidate(struct
> > > dentry *dentry)
> > > {
> > >        /* store_release ensures wait_var_event() sees the update
> > > */
> > >        smp_store_release(&dentry->d_fsdata, NULL);
> > > + smp_mb();
> > >        wake_up_var(&dentry->d_fsdata);
> > > }
> 
> any chance to get this into mainline? It seems that the current git
> master does not inlude smb_mb(); in this code.
> 
> 
I'm adding a fix that will go in to the next merge window.

-- 
Trond Myklebust
Linux NFS client maintainer, Hammerspace
trondmy@kernel.org, trond.myklebust@hammerspace.com