On Fri, 18 Jul 2014 12:44:17 -0400
"J. Bruce Fields" <bfields@xxxxxxxxxxxx> 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 <trond.myklebust@xxxxxxxxxxxxxxx>
> > Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxxxxxxx>
> > Reviewed-by: Christoph Hellwig <hch@xxxxxx>
> > ---
> > 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 <jlayton@xxxxxxxxxxxxxxx>
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