Re: [RFC PATCH] NFSD: Add a Kconfig setting to enable delegated timestamps

[Jeff Layton <jlayton@kernel.org>]

On Tue, 2025-03-11 at 23:06 -0400, cel@kernel.org wrote:
> From: Chuck Lever <chuck.lever@oracle.com>
> 
> After three tries, we still see test failures with delegated
> timestamps. Disable them by default, but leave the implementation
> intact so that development can continue.
> 
> X-Cc: stable@vger.kernel.org # v6.14
> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
> ---
>  fs/nfsd/Kconfig     | 12 +++++++++++-
>  fs/nfsd/nfs4state.c | 16 ++++++++++++++--
>  2 files changed, 25 insertions(+), 3 deletions(-)
> 
> This compiles. Initial testing shows that tests that were previously
> failing are now passing. I would like to include this in v6.15, but
> I will give it a little more time in nfsd-testing.
> 
> diff --git a/fs/nfsd/Kconfig b/fs/nfsd/Kconfig
> index c0bd1509ccd4..792d3fed1b45 100644
> --- a/fs/nfsd/Kconfig
> +++ b/fs/nfsd/Kconfig
> @@ -172,6 +172,16 @@ config NFSD_LEGACY_CLIENT_TRACKING
>  	  recoverydir, or spawn a process directly using a usermodehelper
>  	  upcall.
>  
> -	  These legacy client tracking methods have proven to be probelmatic
> +	  These legacy client tracking methods have proven to be problematic
>  	  and will be removed in the future. Say Y here if you need support
>  	  for them in the interim.
> +
> +config NFSD_V4_DELEG_TIMESTAMPS
> +	bool "Support delegated timestamps"
> +	depends on NFSD_V4
> +	default n
> +	help
> +	  NFSD implements delegated timestamps according to
> +	  draft-ietf-nfsv4-delstid-08 "Extending the Opening of Files". This
> +	  is currently an experimental feature and is therefore left disabled
> +	  by default.
> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> index 2da700635955..2bd63594d8da 100644
> --- a/fs/nfsd/nfs4state.c
> +++ b/fs/nfsd/nfs4state.c
> @@ -5948,11 +5948,23 @@ nfsd4_verify_setuid_write(struct nfsd4_open *open, struct nfsd_file *nf)
>  	return 0;
>  }
>  
> +#ifdef CONFIG_NFSD_V4_DELEG_TIMESTAMPS
> +static bool nfsd4_want_deleg_timestamps(const struct nfsd4_open *open)
> +{
> +	return open->op_deleg_want & OPEN4_SHARE_ACCESS_WANT_DELEG_TIMESTAMPS;
> +}
> +#else /* CONFIG_NFSD_V4_DELEG_TIMESTAMPS */
> +static bool nfsd4_want_deleg_timestamps(const struct nfsd4_open *open)
> +{
> +	return false;
> +}
> +#endif /* CONFIG NFSD_V4_DELEG_TIMESTAMPS */
> +
>  static struct nfs4_delegation *
>  nfs4_set_delegation(struct nfsd4_open *open, struct nfs4_ol_stateid *stp,
>  		    struct svc_fh *parent)
>  {
> -	bool deleg_ts = open->op_deleg_want & OPEN4_SHARE_ACCESS_WANT_DELEG_TIMESTAMPS;
> +	bool deleg_ts = nfsd4_want_deleg_timestamps(open);
>  	struct nfs4_client *clp = stp->st_stid.sc_client;
>  	struct nfs4_file *fp = stp->st_stid.sc_file;
>  	struct nfs4_clnt_odstate *odstate = stp->st_clnt_odstate;
> @@ -6193,8 +6205,8 @@ nfs4_open_delegation(struct svc_rqst *rqstp, struct nfsd4_open *open,
>  		     struct nfs4_ol_stateid *stp, struct svc_fh *currentfh,
>  		     struct svc_fh *fh)
>  {
> -	bool deleg_ts = open->op_deleg_want & OPEN4_SHARE_ACCESS_WANT_DELEG_TIMESTAMPS;
>  	struct nfs4_openowner *oo = openowner(stp->st_stateowner);
> +	bool deleg_ts = nfsd4_want_deleg_timestamps(open);
>  	struct nfs4_client *clp = stp->st_stid.sc_client;
>  	struct svc_fh *parent = NULL;
>  	struct nfs4_delegation *dp;

Thanks for doing this, Chuck.

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