linux-kernel - Re: [PATCH] nfsd: allow SC_STATUS_FREEABLE when searching via nfs4_lookup

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Message-ID: <e6be9dea9084e8c8c46ba3c1d487d3466d51cbc7.camel@kernel.org>
Date: Thu, 13 Feb 2025 07:55:56 -0500
From: Jeff Layton <jlayton@...nel.org>
To: Dai Ngo <dai.ngo@...cle.com>, Chuck Lever <chuck.lever@...cle.com>, Neil
 Brown <neilb@...e.de>, Olga Kornievskaia <okorniev@...hat.com>, Tom Talpey
 <tom@...pey.com>
Cc: linux-nfs@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] nfsd: allow SC_STATUS_FREEABLE when searching via
 nfs4_lookup_stateid()

On Wed, 2025-02-12 at 13:41 -0800, Dai Ngo wrote:
> On 2/12/25 8:29 AM, 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.
> > 
> > Signed-off-by: Jeff Layton <jlayton@...nel.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;
> 
> I think it's safer to add the SC_STATUS_FREEABLE inside the if statement
> that checks for SC_TYPE_DELEG above.
> 

That's not enough. SC_STATUS_ADMIN_REVOKED is always allowed, and for
that to work properly, we need to always allow SC_STATUS_FREEABLE too.

> Also, don't we also need to mark the delegation with SC_STATUS_REVOKED in
> revoke_delegation()?
> 

No. The idea is that the REVOKED flag should be set before calling
revoke_delegation(). Typically they get marked REVOKED or ADMIN_REVOKED
under spinlock, and then we call revoke_delegation() afterward to
finish the job.
 
> >   
> >   	if (ZERO_STATEID(stateid) || ONE_STATEID(stateid) ||
> >   		CLOSE_STATEID(stateid))
> > 
> > ---
> > base-commit: 4990d098433db18c854e75fb0f90d941eb7d479e
> > change-id: 20250212-nfsd-fixes-fa8047082335
> > 
> > Best regards,

-- 
Jeff Layton <jlayton@...nel.org>