Re: [PATCH 1/1] NFSD: fix setting FMODE_NOCMTIME in nfs4_open_delegation

[Jeff Layton <jlayton@kernel.org>]

On Fri, 2025-12-19 at 12:59 -0500, Olga Kornievskaia wrote:
> fstests generic/215 and generic/407 were failing because the server
> wasn't updating mtime properly. When deleg attribute support is not
> compiled in and thus no attribute delegation was given, the server
> was skipping updating mtime and ctime because FMODE_NOCMTIME was
> uncoditionally set for the write delegation.
> 
> Fixes: e5e9b24ab8fa ("nfsd: freeze c/mtime updates with outstanding WRITE_ATTRS delegation")
> Signed-off-by: Olga Kornievskaia <okorniev@redhat.com>
> ---
>  fs/nfsd/nfs4state.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> index 808c24fb5c9a..d64650c47f79 100644
> --- a/fs/nfsd/nfs4state.c
> +++ b/fs/nfsd/nfs4state.c
> @@ -6327,7 +6327,8 @@ nfs4_open_delegation(struct svc_rqst *rqstp, struct nfsd4_open *open,
>  		dp->dl_ctime = stat.ctime;
>  		dp->dl_mtime = stat.mtime;
>  		spin_lock(&f->f_lock);
> -		f->f_mode |= FMODE_NOCMTIME;
> +		if (deleg_ts)
> +			f->f_mode |= FMODE_NOCMTIME;
>  		spin_unlock(&f->f_lock);
>  		trace_nfsd_deleg_write(&dp->dl_stid.sc_stateid);
>  	} else {

Nice catch.

We only want to disable c/mtime updates in the case where timestamps
are delegated. In the non-delegated case, they need to be updated with
every write. This seems correct to me.

Reviewed-by: Jeff Layton <jlayton@kernel.org>