On Thu, Aug 21, 2025 at 11:09 AM Chuck Lever <chuck.lever@xxxxxxxxxx> wrote:
>
> On 8/21/25 9:56 AM, Olga Kornievskaia wrote:
> > On Wed, Aug 20, 2025 at 7:15 PM NeilBrown <neil@xxxxxxxxxx> wrote:
> >>
> >> On Thu, 14 Aug 2025, Olga Kornievskaia wrote:
> >>> On Tue, Aug 12, 2025 at 8:05 PM NeilBrown <neil@xxxxxxxxxx> wrote:
> >>>>
> >>>> On Wed, 13 Aug 2025, Olga Kornievskaia wrote:
> >>>>> When nfsd is in grace and receives an NLM LOCK request which turns
> >>>>> out to have a conflicting delegation, return that the server is in
> >>>>> grace.
> >>>>>
> >>>>> Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx>
> >>>>> Signed-off-by: Olga Kornievskaia <okorniev@xxxxxxxxxx>
> >>>>> ---
> >>>>> fs/lockd/svc4proc.c | 15 +++++++++++++--
> >>>>> 1 file changed, 13 insertions(+), 2 deletions(-)
> >>>>>
> >>>>> diff --git a/fs/lockd/svc4proc.c b/fs/lockd/svc4proc.c
> >>>>> index 109e5caae8c7..7ac4af5c9875 100644
> >>>>> --- a/fs/lockd/svc4proc.c
> >>>>> +++ b/fs/lockd/svc4proc.c
> >>>>> @@ -141,8 +141,19 @@ __nlm4svc_proc_lock(struct svc_rqst *rqstp, struct nlm_res *resp)
> >>>>> resp->cookie = argp->cookie;
> >>>>>
> >>>>> /* Obtain client and file */
> >>>>> - if ((resp->status = nlm4svc_retrieve_args(rqstp, argp, &host, &file)))
> >>>>> - return resp->status == nlm_drop_reply ? rpc_drop_reply :rpc_success;
> >>>>> + resp->status = nlm4svc_retrieve_args(rqstp, argp, &host, &file);
> >>>>> + switch (resp->status) {
> >>>>> + case 0:
> >>>>> + break;
> >>>>> + case nlm_drop_reply:
> >>>>> + if (locks_in_grace(SVC_NET(rqstp))) {
> >>>>> + resp->status = nlm_lck_denied_grace_period;
> >>>>
> >>>> I think this is wrong. If the lock request has the "reclaim" flag set,
> >>>> then nlm_lck_denied_grace_period is not a meaningful error.
> >>>> nlm4svc_retrieve_args() returns nlm_drop_reply when there is a delay
> >>>> getting a response to an upcall to mountd. For NLM the request really
> >>>> must be dropped.
> >>>
> >>> Thank you for pointing out this case so we are suggesting to.
> >>>
> >>> if (locks_in_grace(SVC_NET(rqstp)) && !argp->reclaim)
> >>>
> >>> However, I've been looking and looking but I cannot figure out how
> >>> nlm4svc_retrieve_args() would ever get nlm_drop_reply. You say it can
> >>> happen during the upcall to mountd. So that happens within nfsd_open()
> >>> call and a part of fh_verify().
> >>> To return nlm_drop_reply, nlm_fopen() must have gotten nfserr_dropit
> >>> from the nfsd_open(). I have searched and searched but I don't see
> >>> anything that ever sets nfserr_dropit (NFSERR_DROPIT).
> >>>
> >>> I searched the logs and nfserr_dropit was an error that was EAGAIN
> >>> translated into but then removed by the following patch.
> >>
> >> Oh. I didn't know that.
> >> We now use RQ_DROPME instead.
> >> I guess we should remove NFSERR_DROPIT completely as it not used at all
> >> any more.
> >>
> >> Though returning nfserr_jukebox to an v2 client isn't a good idea....
> >
> > I'll take your word for you.
> >
> >> So I guess my main complaint isn't valid, but I still don't like this
> >> patch. It seems an untidy place to put the locks_in_grace test.
> >> Other callers of nlm4svc_retrieve_args() check locks_in_grace() before
> >> making that call. __nlm4svc_proc_lock probably should too. Or is there
> >> a reason that it is delayed until the middle of nlmsvc_lock()..
> >
> > I thought the same about why not adding the in_grace check and decided
> > that it was probably because you dont want to deny a lock if there are
> > no conflicts. If we add it, somebody might notice and will complain
> > that they can't get their lock when there are no conflicts.
> >
> >> The patch is not needed and isn't clearly an improvement, so I would
> >> rather it were dropped.
> >
> > I'm not against dropping this patch if the conclusion is that dropping
> > the packet is no worse than returning in_grace error.
>
> I dropped both of these from nfsd-testing. If a fix is still needed,
> let's start again with fresh patches.
Can you clarify when you said "both"?
What objections are there for the 1st patch in the series. It solves a
problem and a fix is needed. This one I agree is not needed but I
thought was an improvement.
>
>
> >> Thanks,
> >> NeilBrown
> >>
> >>
> >>>
> >>> commit 062304a815fe10068c478a4a3f28cf091c55cb82
> >>> Author: J. Bruce Fields <bfields@xxxxxxxxxxxx>
> >>> Date: Sun Jan 2 22:05:33 2011 -0500
> >>>
> >>> nfsd: stop translating EAGAIN to nfserr_dropit
> >>>
> >>> diff --git a/fs/nfsd/nfsproc.c b/fs/nfsd/nfsproc.c
> >>> index dc9c2e3fd1b8..fd608a27a8d5 100644
> >>> --- a/fs/nfsd/nfsproc.c
> >>> +++ b/fs/nfsd/nfsproc.c
> >>> @@ -735,7 +735,8 @@ nfserrno (int errno)
> >>> { nfserr_stale, -ESTALE },
> >>> { nfserr_jukebox, -ETIMEDOUT },
> >>> { nfserr_jukebox, -ERESTARTSYS },
> >>> - { nfserr_dropit, -EAGAIN },
> >>> + { nfserr_jukebox, -EAGAIN },
> >>> + { nfserr_jukebox, -EWOULDBLOCK },
> >>> { nfserr_jukebox, -ENOMEM },
> >>> { nfserr_badname, -ESRCH },
> >>> { nfserr_io, -ETXTBSY },
> >>>
> >>> so if fh_verify is failing whatever it is returning, it is not
> >>> nfserr_dropit nor is it nfserr_jukebox which means nlm_fopen() would
> >>> translate it to nlm_failed which with my patch would not trigger
> >>> nlm_lck_denied_grace_period error but resp->status would be set to
> >>> nlm_failed.
> >>>
> >>> So I circle back to I hope that convinces you that we don't need a
> >>> check for the reclaim lock.
> >>>
> >>> I believe nlm_drop_reply is nfsd_open's jukebox error, one of which is
> >>> delegation recall. it can be a memory failure. But I'm sure when
> >>> EWOULDBLOCK occurs.
> >>>
> >>>> At the very least we need to guard against the reclaim flag being set in
> >>>> the above test. But I would much rather a more clear distinction were
> >>>> made between "drop because of a conflicting delegation" and "drop
> >>>> because of a delay getting upcall response".
> >>>> Maybe a new "nlm_conflicting_delegtion" return from ->fopen which nlm4
> >>>> (and ideally nlm2) handles appropriately.
> >>>
> >>>
> >>>> NeilBrown
> >>>>
> >>>>
> >>>>> + return rpc_success;
> >>>>> + }
> >>>>> + return nlm_drop_reply;
> >>>>> + default:
> >>>>> + return rpc_success;
> >>>>> + }
> >>>>>
> >>>>> /* Now try to lock the file */
> >>>>> resp->status = nlmsvc_lock(rqstp, file, host, &argp->lock,
> >>>>> --
> >>>>> 2.47.1
> >>>>>
> >>>>>
> >>>>
> >>>>
> >>>
> >>
>
>
> --
> Chuck Lever
