Return-Path: Received: from mx2.netapp.com ([216.240.18.37]:62497 "EHLO mx2.netapp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751289Ab0IHUiO convert rfc822-to-8bit (ORCPT ); Wed, 8 Sep 2010 16:38:14 -0400 Subject: Re: [PATCH 2/2] We should clear NFS_DELEGATED_STATE after return delegation From: Trond Myklebust To: Bian Naimeng Cc: linux-nfs@vger.kernel.org, "J. Bruce Fields" In-Reply-To: <4C86FECF.2050103@cn.fujitsu.com> References: <4C592F85.8070308@cn.fujitsu.com> <4C59306A.9090302@cn.fujitsu.com> <1280925913.3011.23.camel@heimdal.trondhjem.org> <4C5A213F.9000506@cn.fujitsu.com> <1281013423.2948.1.camel@heimdal.trondhjem.org> <4C5B8B48.4050008@cn.fujitsu.com> <1281101448.3586.11.camel@heimdal.trondhjem.org> <4C68EDAE.5000201@cn.fujitsu.com> <1282087012.18385.30.camel@heimdal.trondhjem.org> <4C7DF56B.3040206@cn.fujitsu.com> <1283897068.9097.15.camel@heimdal.trondhjem.org> <4C86E7FA.7020701@cn.fujitsu.com> <1283911036.16070.1.camel@heimdal.trondhjem.org> <4C86FECF.2050103@cn.fujitsu.com> Content-Type: text/plain; charset="UTF-8" Date: Wed, 08 Sep 2010 16:37:25 -0400 Message-ID: <1283978245.2905.23.camel@heimdal.trondhjem.org> Sender: linux-nfs-owner@vger.kernel.org List-ID: MIME-Version: 1.0 On Wed, 2010-09-08 at 11:11 +0800, Bian Naimeng wrote: > If there are not any delegation at this inode, we should clear stateid's > NFS_DELEGATED_STATE when update it. > > Signed-off-by: Bian Naimeng > > --- > fs/nfs/delegation.c | 1 + > fs/nfs/nfs4proc.c | 12 +++++++++++- > 2 files changed, 12 insertions(+), 1 deletions(-) > > diff --git a/fs/nfs/delegation.c b/fs/nfs/delegation.c > index b9c3c43..62f296e 100644 > --- a/fs/nfs/delegation.c > +++ b/fs/nfs/delegation.c > @@ -106,6 +106,7 @@ again: > continue; > if (memcmp(state->stateid.data, stateid->data, sizeof(state->stateid.data)) != 0) > continue; > + clear_bit(NFS_DELEGATED_STATE, &state->flags); > get_nfs_open_context(ctx); > spin_unlock(&inode->i_lock); > err = nfs4_open_delegation_recall(ctx, state, stateid); > diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c > index 089da5b..f7e45b4 100644 > --- a/fs/nfs/nfs4proc.c > +++ b/fs/nfs/nfs4proc.c > @@ -919,8 +919,18 @@ static int update_open_stateid(struct nfs4_state *state, nfs4_stateid *open_stat > > rcu_read_lock(); > deleg_cur = rcu_dereference(nfsi->delegation); > - if (deleg_cur == NULL) > + if (deleg_cur == NULL) { > + if (delegation == NULL && open_stateid != NULL) { Well... What I really meant was that we should make sure that we don't get into this situation. I think the clear_bit() should be unconditional if delegation == NULL, but if the (delegation == NULL && open_stateid == NULL) _can_ occur, then we should probably mark the nfs4_state for recovery using nfs4_state_mark_reclaim_nograce(), and then fire of a recovery thread. > + /* > + * FIXME: If the state has NFS_DELEGATED_STATE bit > + * we catch a race. Maybe should recover its open > + * stateid, now we just clear the NFS_DELEGATED_STATE > + * bit. > + */ > + clear_bit(NFS_DELEGATED_STATE, &state->flags); > + } > goto no_delegation; > + } > > spin_lock(&deleg_cur->lock); > if (nfsi->delegation != deleg_cur || > -- > 1.7.0 > > > >>>> diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c > >>>> index 36400d3..c0c0320 100644 > >>>> --- a/fs/nfs/nfs4proc.c > >>>> +++ b/fs/nfs/nfs4proc.c > >>>> @@ -900,8 +900,18 @@ static int update_open_stateid(struct nfs4_state *state, nfs4_stateid *open_stat > >>>> > >>>> rcu_read_lock(); > >>>> deleg_cur = rcu_dereference(nfsi->delegation); > >>>> - if (deleg_cur == NULL) > >>>> + if (deleg_cur == NULL) { > >>>> + if (delegation == NULL && > >>>> + test_bit(NFS_DELEGATED_STATE, &state->flags)) { > >>> Any reason why we can't ditch the 'test_bit'? > >>> > >> Because i am not sure it's ok that we just clear_bit at here. > >> If you think it's ok, i'd be fine with removing this test_bit. > > > > How is it different from just clearing the bit? > > > >>>> + /*FIXME: If the state has NFS_DELEGATED_STATE bit, > >>>> + * we catch a race. Maybe should recover its open > >>>> + * stateid, here we just clear the NFS_DELEGATED_STATE > >>>> + * bit. > >>> Can this ever be called with both deleg_cur==NULL and > >>> open_stateid==NULL? If so, then we still have a bug. > >>> > >> Yes, i will add a checking. Thanks very much. > >> > >>>> + */ > >>>> + clear_bit(NFS_DELEGATED_STATE, &state->flags); > >>>> + } > >>>> goto no_delegation; > >>>> + } > >>>> > >>>> spin_lock(&deleg_cur->lock); > >>>> if (nfsi->delegation != deleg_cur || > > > > Cheers > > Trond > > > > > > >