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.
>
> 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
>
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