Return-Path: linux-nfs-owner@vger.kernel.org Received: from mail-qg0-f65.google.com ([209.85.192.65]:56365 "EHLO mail-qg0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S935058AbaGRRY6 (ORCPT ); Fri, 18 Jul 2014 13:24:58 -0400 Received: by mail-qg0-f65.google.com with SMTP id z60so900067qgd.0 for ; Fri, 18 Jul 2014 10:24:58 -0700 (PDT) From: Jeff Layton Date: Fri, 18 Jul 2014 13:24:36 -0400 To: "J. Bruce Fields" Cc: hch@infradead.org, linux-nfs@vger.kernel.org Subject: Re: [PATCH v4 04/10] nfsd: Fix delegation revocation Message-ID: <20140718132436.34924fc4@f20.localdomain> In-Reply-To: <20140718164417.GB8811@fieldses.org> References: <1405696416-32585-1-git-send-email-jlayton@primarydata.com> <1405696416-32585-5-git-send-email-jlayton@primarydata.com> <20140718164417.GB8811@fieldses.org> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-nfs-owner@vger.kernel.org List-ID: On Fri, 18 Jul 2014 12:44:17 -0400 "J. Bruce Fields" wrote: > On Fri, Jul 18, 2014 at 11:13:30AM -0400, Jeff Layton wrote: > > Ensure that the delegations cannot be found by the laundromat etc once > > we add them to the various 'revoke' lists. > > So if I understand right, the big mutex protects all of this right now, > so this is all just moving the unhashing under a finer-grained lock to > prevent that in-between state being exposed after the big lock's > dropped. Looks reasonable. > > --b. > Yes, sorry -- I forgot the obligatory "this is not a problem until the client_mutex goes away" comment... > > > > Signed-off-by: Trond Myklebust > > Signed-off-by: Jeff Layton > > Reviewed-by: Christoph Hellwig > > --- > > fs/nfsd/nfs4state.c | 37 +++++++++++++++++++++---------------- > > 1 file changed, 21 insertions(+), 16 deletions(-) > > > > diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c > > index 60ae21abce00..7c5233427c9b 100644 > > --- a/fs/nfsd/nfs4state.c > > +++ b/fs/nfsd/nfs4state.c > > @@ -650,13 +650,13 @@ hash_delegation_locked(struct nfs4_delegation *dp, struct nfs4_file *fp) > > list_add(&dp->dl_perclnt, &dp->dl_stid.sc_client->cl_delegations); > > } > > > > -/* Called under the state lock. */ > > static void > > -unhash_delegation(struct nfs4_delegation *dp) > > +unhash_delegation_locked(struct nfs4_delegation *dp) > > { > > struct nfs4_file *fp = dp->dl_file; > > > > - spin_lock(&state_lock); > > + lockdep_assert_held(&state_lock); > > + > > dp->dl_stid.sc_type = NFS4_CLOSED_DELEG_STID; > > spin_lock(&fp->fi_lock); > > list_del_init(&dp->dl_perclnt); > > @@ -665,7 +665,6 @@ unhash_delegation(struct nfs4_delegation *dp) > > spin_unlock(&fp->fi_lock); > > if (fp) > > nfs4_put_deleg_lease(fp); > > - spin_unlock(&state_lock); > > } > > > > static void destroy_revoked_delegation(struct nfs4_delegation *dp) > > @@ -676,7 +675,9 @@ static void destroy_revoked_delegation(struct nfs4_delegation *dp) > > > > static void destroy_delegation(struct nfs4_delegation *dp) > > { > > - unhash_delegation(dp); > > + spin_lock(&state_lock); > > + unhash_delegation_locked(dp); > > + spin_unlock(&state_lock); > > nfs4_put_delegation(dp); > > } > > > > @@ -685,11 +686,10 @@ static void revoke_delegation(struct nfs4_delegation *dp) > > struct nfs4_client *clp = dp->dl_stid.sc_client; > > > > if (clp->cl_minorversion == 0) > > - destroy_delegation(dp); > > + destroy_revoked_delegation(dp); > > else { > > - unhash_delegation(dp); > > dp->dl_stid.sc_type = NFS4_REVOKED_DELEG_STID; > > - list_add(&dp->dl_recall_lru, &clp->cl_revoked); > > + list_move(&dp->dl_recall_lru, &clp->cl_revoked); > > } > > } > > > > @@ -1447,15 +1447,16 @@ destroy_client(struct nfs4_client *clp) > > spin_lock(&state_lock); > > while (!list_empty(&clp->cl_delegations)) { > > dp = list_entry(clp->cl_delegations.next, struct nfs4_delegation, dl_perclnt); > > - list_del_init(&dp->dl_perclnt); > > + unhash_delegation_locked(dp); > > /* Ensure that deleg break won't try to requeue it */ > > ++dp->dl_time; > > - list_move(&dp->dl_recall_lru, &reaplist); > > + list_add(&dp->dl_recall_lru, &reaplist); > > } > > spin_unlock(&state_lock); > > while (!list_empty(&reaplist)) { > > dp = list_entry(reaplist.next, struct nfs4_delegation, dl_recall_lru); > > - destroy_delegation(dp); > > + list_del_init(&dp->dl_recall_lru); > > + nfs4_put_delegation(dp); > > } > > list_splice_init(&clp->cl_revoked, &reaplist); > > while (!list_empty(&reaplist)) { > > @@ -3655,7 +3656,7 @@ nfs4_open_delegation(struct net *net, struct svc_fh *fh, > > open->op_delegate_type = NFS4_OPEN_DELEGATE_READ; > > return; > > out_free: > > - destroy_delegation(dp); > > + nfs4_put_delegation(dp); > > out_no_deleg: > > open->op_delegate_type = NFS4_OPEN_DELEGATE_NONE; > > if (open->op_claim_type == NFS4_OPEN_CLAIM_PREVIOUS && > > @@ -3894,7 +3895,8 @@ nfs4_laundromat(struct nfsd_net *nn) > > new_timeo = min(new_timeo, t); > > break; > > } > > - list_move(&dp->dl_recall_lru, &reaplist); > > + unhash_delegation_locked(dp); > > + list_add(&dp->dl_recall_lru, &reaplist); > > } > > spin_unlock(&state_lock); > > list_for_each_safe(pos, next, &reaplist) { > > @@ -5369,7 +5371,8 @@ static u64 nfsd_find_all_delegations(struct nfs4_client *clp, u64 max, > > * don't monkey with it now that we are. > > */ > > ++dp->dl_time; > > - list_move(&dp->dl_recall_lru, victims); > > + unhash_delegation_locked(dp); > > + list_add(&dp->dl_recall_lru, victims); > > } > > if (++count == max) > > break; > > @@ -5624,12 +5627,14 @@ nfs4_state_shutdown_net(struct net *net) > > spin_lock(&state_lock); > > list_for_each_safe(pos, next, &nn->del_recall_lru) { > > dp = list_entry (pos, struct nfs4_delegation, dl_recall_lru); > > - list_move(&dp->dl_recall_lru, &reaplist); > > + unhash_delegation_locked(dp); > > + list_add(&dp->dl_recall_lru, &reaplist); > > } > > spin_unlock(&state_lock); > > list_for_each_safe(pos, next, &reaplist) { > > dp = list_entry (pos, struct nfs4_delegation, dl_recall_lru); > > - destroy_delegation(dp); > > + list_del_init(&dp->dl_recall_lru); > > + nfs4_put_delegation(dp); > > } > > > > nfsd4_client_tracking_exit(net); > > -- > > 1.9.3 > > -- Jeff Layton