nfsd: deal with revoked delegations appropriately

commit 95da1b3a5aded124dd1bda1e3cdb876184813140 upstream.

If a delegation has been revoked by the server, operations using that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>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index ca9ebc3..421935f 100644 (file)
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -3829,7 +3829,8 @@ 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);
@@ -3852,6 +3853,12 @@ 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) {
@@ -4696,6 +4703,16 @@ 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;
@@ -4710,6 +4727,12 @@ 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;
 }