Re: [PATCH] nfsd: allow SC_STATUS_FREEABLE when searching via nfs4_lookup_stateid()

[Jeff Layton <jlayton@kernel.org>]

On Thu, 2025-02-13 at 08:13 +1100, NeilBrown wrote:
> On Thu, 13 Feb 2025, Jeff Layton wrote:
> > When a delegation is revoked, it's initially marked with
> > SC_STATUS_REVOKED, or SC_STATUS_ADMIN_REVOKED and later, it's marked
> > with the SC_STATUS_FREEABLE flag, which denotes that it is waiting for
> > s FREE_STATEID call.
> > 
> > nfs4_lookup_stateid() accepts a statusmask that includes the status
> > flags that a found stateid is allowed to have. Currently, that mask
> > never includes SC_STATUS_FREEABLE, which means that revoked delegations
> > are (almost) never found.
> > 
> > Add SC_STATUS_FREEABLE to the always-allowed status flags.
> 
> There are 4 calls to nfsd4_lookup_stateid().  One already has
> SC_STATUS_FREEABLE passed.  Which of the others need it?
 
> If all of them, then this patch is sensible but should also remove the
> flag in the one place it is already passed.
> If only one other call needs it, then maybe we should just pass it
> there?
> 
> Could you at least include in the description some detail of what
> request is failing and which particular nfsd4_lookup_stateid() call is
> relevant in that case?
> 
> Thanks,
> NeilBrown
> 

I think they all need it.

The DELEG8 test gets a delegation, and then lets the lease time out. It
then does a READ op and tests that it gets back NFS4ERR_DELEG_REVOKED.
The read path calls nfs4_preprocess_stateid_op(), so it's needed there
specifically to fix that bug.

1ac3629bf0125 ensures that SC_STATUS_ADMIN_REVOKED is always set in the
allowed mask. If that's always allowed, then FREEABLE must be too.
There is only a very narrow window of time when ADMIN_REVOKED or
REVOKED is set, and FREEABLE is not.

I'll respin and remove the other FREEABLE flag, since I think it should
be implied everywhere.

> 
> > 
> > Signed-off-by: Jeff Layton <jlayton@kernel.org>
> > ---
> > This fixes the pynfs DELEG8 test.
> > ---
> >  fs/nfsd/nfs4state.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> > index 153eeea2c7c999d003cd1f36cecb0dd4f6e049b8..56bf07d623d085589823f3fba18afa62c0b3dbd2 100644
> > --- a/fs/nfsd/nfs4state.c
> > +++ b/fs/nfsd/nfs4state.c
> > @@ -7051,7 +7051,7 @@ nfsd4_lookup_stateid(struct nfsd4_compound_state *cstate,
> >  		 */
> >  		statusmask |= SC_STATUS_REVOKED;
> >  
> > -	statusmask |= SC_STATUS_ADMIN_REVOKED;
> > +	statusmask |= SC_STATUS_ADMIN_REVOKED | SC_STATUS_FREEABLE;
> >  
> >  	if (ZERO_STATEID(stateid) || ONE_STATEID(stateid) ||
> >  		CLOSE_STATEID(stateid))
> > 
> > ---
> > base-commit: 4990d098433db18c854e75fb0f90d941eb7d479e
> > change-id: 20250212-nfsd-fixes-fa8047082335
> > 
> > Best regards,
> > -- 
> > Jeff Layton <jlayton@kernel.org>
> > 
> > 
> 

-- 
Jeff Layton <jlayton@kernel.org>