Return-Path: Received: from cn.fujitsu.com ([222.73.24.84]:61961 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1753531Ab0IAGko (ORCPT ); Wed, 1 Sep 2010 02:40:44 -0400 Message-ID: <4C7DF56B.3040206@cn.fujitsu.com> Date: Wed, 01 Sep 2010 14:40:43 +0800 From: Bian Naimeng To: Trond Myklebust CC: linux-nfs@vger.kernel.org, "J. Bruce Fields" Subject: Re: [PATCH 2/2] We should clear NFS_DELEGATED_STATE after return delegation 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> In-Reply-To: <1282087012.18385.30.camel@heimdal.trondhjem.org> Content-Type: text/plain; charset=Shift_JIS Sender: linux-nfs-owner@vger.kernel.org List-ID: MIME-Version: 1.0 > On Mon, 2010-08-16 at 15:50 +0800, Bian Naimeng wrote: >>>>>>>> We should clear NFS_DELEGATED_STATE bit for inode->open_states after return delegation. ... snip ... >> A open state can be found at nfsi->open_states and owner->so_states always, but >> it not be found at nfsi->open_files until we call nfs4_intent_set_file. >> >> At _nfs4_do_open, we will invoke nfs4_return_incompatible_delegation to return a >> delegation, a open stateid which set NFS_DELEGATED_STATE bit may not be found at >> nfsi->open_files, but it still at nfsi->open_states, so we do not clear >> NFS_DELEGATED_STATE bit for it. >> >> Then _nfs4_do_open will find it by nfs4_get_open_state, and we still use it >> as a delegation, some error will occur. >> > > OK. I see agree that is a race, but AFAICS, your fix means that we end > up with an nfs_state structure that has cleared NFS_DELEGATED_STATE, but > that did not recover its open stateid. > Hi trond, what do you think about this one? Best Regards Bian ------------------------------------------------------------------------- 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 83bb16f..3a7a19d 100644 --- a/fs/nfs/delegation.c +++ b/fs/nfs/delegation.c @@ -109,6 +109,7 @@ 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 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)) { + /*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. + */ + clear_bit(NFS_DELEGATED_STATE, &state->flags); + } goto no_delegation; + } spin_lock(&deleg_cur->lock); if (nfsi->delegation != deleg_cur || -- 1.6.5.2