nfsd: nfs4_preprocess_seqid_op should only set *stpp on success

Not technically a bugfix, since nothing tries to use the return pointer
if this function doesn't return success, but it could be a problem
with some coming changes.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

fs/nfsd/nfs4state.c

@@ -3953,6 +3953,7 @@ nfs4_preprocess_seqid_op(struct nfsd4_compound_state *cstate, u32 seqid,
 {
 	__be32 status;
 	struct nfs4_stid *s;
+	struct nfs4_ol_stateid *stp = NULL;
 
 	dprintk("NFSD: %s: seqid=%d stateid = " STATEID_FMT "\n", __func__,
 		seqid, STATEID_VAL(stateid));
@@ -3962,11 +3963,14 @@ nfs4_preprocess_seqid_op(struct nfsd4_compound_state *cstate, u32 seqid,
 				      cstate->minorversion, nn);
 	if (status)
 		return status;
-	*stpp = openlockstateid(s);
+	stp = openlockstateid(s);
 	if (!nfsd4_has_session(cstate))
-		cstate->replay_owner = (*stpp)->st_stateowner;
+		cstate->replay_owner = stp->st_stateowner;
 
-	return nfs4_seqid_op_checks(cstate, stateid, seqid, *stpp);
+	status = nfs4_seqid_op_checks(cstate, stateid, seqid, stp);
+	if (!status)
+		*stpp = stp;
+	return status;
 }
 
 static __be32 nfs4_preprocess_confirmed_seqid_op(struct nfsd4_compound_state *cstate, u32 seqid,