nfsd: deal with revoked delegations appropriately

If a delegation has been revoked by the server, operations using that
delegation should error out with NFS4ERR_DELEG_REVOKED in the >4.1
case, and NFS4ERR_BAD_STATEID otherwise.

The server needs NFSv4.1 clients to explicitly free revoked delegations.
If the server returns NFS4ERR_DELEG_REVOKED, the client will do that;
otherwise it may just forget about the delegation and be unable to
recover when it later sees SEQ4_STATUS_RECALLABLE_STATE_REVOKED set on a
SEQUENCE reply.  That can cause the Linux 4.1 client to loop in its
stage manager.

Signed-off-by: Andrew Elble <aweits@rit.edu>
Reviewed-by: Trond Myklebust <trond.myklebust@primarydata.com>
Cc: stable@vger.kernel.org
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

1 files changed, 24 insertions, 1 deletions

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index ecbc7b0dfa4d..b82817767b9d 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -4016,7 +4016,8 @@ static struct nfs4_delegation *find_deleg_stateid(struct nfs4_client *cl, statei
 {
         struct nfs4_stid *ret;
 
-        ret = find_stateid_by_type(cl, s, NFS4_DELEG_STID);
+        ret = find_stateid_by_type(cl, s,
+                                NFS4_DELEG_STID|NFS4_REVOKED_DELEG_STID);
         if (!ret)
                 return NULL;
         return delegstateid(ret);
@@ -4039,6 +4040,12 @@ nfs4_check_deleg(struct nfs4_client *cl, struct nfsd4_open *open,
         deleg = find_deleg_stateid(cl, &open->op_delegate_stateid);
         if (deleg == NULL)
                 goto out;
+        if (deleg->dl_stid.sc_type == NFS4_REVOKED_DELEG_STID) {
+                nfs4_put_stid(&deleg->dl_stid);
+                if (cl->cl_minorversion)
+                        status = nfserr_deleg_revoked;
+                goto out;
+        }
         flags = share_access_to_flags(open->op_share_access);
         status = nfs4_check_delegmode(deleg, flags);
         if (status) {
@@ -4908,6 +4915,16 @@ nfsd4_lookup_stateid(struct nfsd4_compound_state *cstate,
                      struct nfs4_stid **s, struct nfsd_net *nn)
 {
         __be32 status;
+        bool return_revoked = false;
+
+        /*
+         *  only return revoked delegations if explicitly asked.
+         *  otherwise we report revoked or bad_stateid status.
+         */
+        if (typemask & NFS4_REVOKED_DELEG_STID)
+                return_revoked = true;
+        else if (typemask & NFS4_DELEG_STID)
+                typemask |= NFS4_REVOKED_DELEG_STID;
 
         if (ZERO_STATEID(stateid) || ONE_STATEID(stateid))
                 return nfserr_bad_stateid;
@@ -4922,6 +4939,12 @@ nfsd4_lookup_stateid(struct nfsd4_compound_state *cstate,
         *s = find_stateid_by_type(cstate->clp, stateid, typemask);
         if (!*s)
                 return nfserr_bad_stateid;
+        if (((*s)->sc_type == NFS4_REVOKED_DELEG_STID) && !return_revoked) {
+                nfs4_put_stid(*s);
+                if (cstate->minorversion)
+                        return nfserr_deleg_revoked;
+                return nfserr_bad_stateid;
+        }
         return nfs_ok;
 }