nfsd4: implement SEQ4_STATUS_RECALLABLE_STATE_REVOKED

A 4.1 server must notify a client that has had any state revoked using
the SEQ4_STATUS_RECALLABLE_STATE_REVOKED flag.  The client can figure
out exactly which state is the problem using CHECK_STATEID and then free
it using FREE_STATEID.  The status flag will be unset once all such
revoked stateids are freed.

Our server's only recallable state is delegations.  So we keep with each
4.1 client a list of delegations that have timed out and been recalled,
but haven't yet been freed by FREE_STATEID.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>

2 files changed, 50 insertions, 8 deletions

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index add9721ab059..3b84700d1bd7 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -445,7 +445,6 @@ static void unhash_stid(struct nfs4_stid *s)
 static void
 unhash_delegation(struct nfs4_delegation *dp)
 {
-        unhash_stid(&dp->dl_stid);
         list_del_init(&dp->dl_perclnt);
         spin_lock(&recall_lock);
         list_del_init(&dp->dl_perfile);
@@ -454,10 +453,37 @@ unhash_delegation(struct nfs4_delegation *dp)
         nfs4_put_deleg_lease(dp->dl_file);
         put_nfs4_file(dp->dl_file);
         dp->dl_file = NULL;
+}
+
+
+
+static void destroy_revoked_delegation(struct nfs4_delegation *dp)
+{
+        list_del_init(&dp->dl_recall_lru);
         remove_stid(&dp->dl_stid);
         nfs4_put_delegation(dp);
 }
 
+static void destroy_delegation(struct nfs4_delegation *dp)
+{
+        unhash_delegation(dp);
+        remove_stid(&dp->dl_stid);
+        nfs4_put_delegation(dp);
+}
+
+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);
+        else {
+                unhash_delegation(dp);
+                dp->dl_stid.sc_type = NFS4_REVOKED_DELEG_STID;
+                list_add(&dp->dl_recall_lru, &clp->cl_revoked);
+        }
+}
+
 /* 
  * SETCLIENTID state 
  */
@@ -1114,7 +1140,7 @@ destroy_client(struct nfs4_client *clp)
         spin_unlock(&recall_lock);
         while (!list_empty(&reaplist)) {
                 dp = list_entry(reaplist.next, struct nfs4_delegation, dl_recall_lru);
-                unhash_delegation(dp);
+                destroy_delegation(dp);
         }
         while (!list_empty(&clp->cl_openowners)) {
                 oo = list_entry(clp->cl_openowners.next, struct nfs4_openowner, oo_perclient);
@@ -1310,6 +1336,7 @@ static struct nfs4_client *create_client(struct xdr_netobj name,
         INIT_LIST_HEAD(&clp->cl_delegations);
         INIT_LIST_HEAD(&clp->cl_lru);
         INIT_LIST_HEAD(&clp->cl_callbacks);
+        INIT_LIST_HEAD(&clp->cl_revoked);
         spin_lock_init(&clp->cl_lock);
         nfsd4_init_callback(&clp->cl_cb_null);
         clp->cl_time = get_seconds();
@@ -2171,6 +2198,8 @@ out:
         default:
                 seq->status_flags = 0;
         }
+        if (!list_empty(&clp->cl_revoked))
+                seq->status_flags |= SEQ4_STATUS_RECALLABLE_STATE_REVOKED;
 out_no_session:
         kfree(conn);
         spin_unlock(&nn->client_lock);
@@ -3297,7 +3326,7 @@ nfs4_laundromat(struct nfsd_net *nn)
         spin_unlock(&recall_lock);
         list_for_each_safe(pos, next, &reaplist) {
                 dp = list_entry (pos, struct nfs4_delegation, dl_recall_lru);
-                unhash_delegation(dp);
+                revoke_delegation(dp);
         }
         test_val = nn->nfsd4_lease;
         list_for_each_safe(pos, next, &nn->close_lru) {
@@ -3459,6 +3488,8 @@ static __be32 nfsd4_validate_stateid(struct nfs4_client *cl, stateid_t *stateid)
         switch (s->sc_type) {
         case NFS4_DELEG_STID:
                 return nfs_ok;
+        case NFS4_REVOKED_DELEG_STID:
+                return nfserr_deleg_revoked;
         case NFS4_OPEN_STID:
         case NFS4_LOCK_STID:
                 ols = openlockstateid(s);
@@ -3602,6 +3633,7 @@ nfsd4_free_stateid(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 {
         stateid_t *stateid = &free_stateid->fr_stateid;
         struct nfs4_stid *s;
+        struct nfs4_delegation *dp;
         struct nfs4_client *cl = cstate->session->se_client;
         __be32 ret = nfserr_bad_stateid;
 
@@ -3623,6 +3655,11 @@ nfsd4_free_stateid(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
                 else
                         ret = nfserr_locks_held;
                 break;
+        case NFS4_REVOKED_DELEG_STID:
+                dp = delegstateid(s);
+                destroy_revoked_delegation(dp);
+                ret = nfs_ok;
+                break;
         default:
                 ret = nfserr_bad_stateid;
         }
@@ -3647,10 +3684,12 @@ static __be32 nfs4_seqid_op_checks(struct nfsd4_compound_state *cstate, stateid_
         status = nfsd4_check_seqid(cstate, sop, seqid);
         if (status)
                 return status;
-        if (stp->st_stid.sc_type == NFS4_CLOSED_STID)
+        if (stp->st_stid.sc_type == NFS4_CLOSED_STID
+                || stp->st_stid.sc_type == NFS4_REVOKED_DELEG_STID)
                 /*
                  * "Closed" stateid's exist *only* to return
-                 * nfserr_replay_me from the previous step.
+                 * nfserr_replay_me from the previous step, and
+                 * revoked delegations are kept only for free_stateid.
                  */
                 return nfserr_bad_stateid;
         status = check_stateid_generation(stateid, &stp->st_stid.sc_stateid, nfsd4_has_session(cstate));
@@ -3913,7 +3952,7 @@ nfsd4_delegreturn(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
         if (status)
                 goto out;
 
-        unhash_delegation(dp);
+        destroy_delegation(dp);
 out:
         nfs4_unlock_state();
 
@@ -4763,7 +4802,7 @@ u64 nfsd_forget_client_delegations(struct nfs4_client *clp, u64 max)
         spin_unlock(&recall_lock);
 
         list_for_each_entry_safe(dp, next, &victims, dl_recall_lru)
-                unhash_delegation(dp);
+                revoke_delegation(dp);
 
         return count;
 }
@@ -5018,7 +5057,7 @@ nfs4_state_shutdown_net(struct net *net)
         spin_unlock(&recall_lock);
         list_for_each_safe(pos, next, &reaplist) {
                 dp = list_entry (pos, struct nfs4_delegation, dl_recall_lru);
-                unhash_delegation(dp);
+                destroy_delegation(dp);
         }
 
         nfsd4_client_tracking_exit(net);
diff --git a/fs/nfsd/state.h b/fs/nfsd/state.h
index 13ec4853e9af..274e2a114e05 100644
--- a/fs/nfsd/state.h
+++ b/fs/nfsd/state.h
@@ -79,6 +79,8 @@ struct nfs4_stid {
 #define NFS4_DELEG_STID 4
 /* For an open stateid kept around *only* to process close replays: */
 #define NFS4_CLOSED_STID 8
+/* For a deleg stateid kept around only to process free_stateid's: */
+#define NFS4_REVOKED_DELEG_STID 16
         unsigned char sc_type;
         stateid_t sc_stateid;
         struct nfs4_client *sc_client;
@@ -238,6 +240,7 @@ struct nfs4_client {
         struct list_head        cl_openowners;
         struct idr              cl_stateids;    /* stateid lookup */
         struct list_head        cl_delegations;
+        struct list_head        cl_revoked;     /* unacknowledged, revoked 4.1 state */
         struct list_head        cl_lru;         /* tail queue */
         struct xdr_netobj       cl_name;        /* id generated by client */
         nfs4_verifier           cl_verifier;    /* generated by client */