nfsd: fix the check for confirmed openowner in nfs4_preprocess_stateid_op

commit ebe9cb3b upstream.

If we find a non-confirmed openowner we jump to exit the function, but do
not set an error value.  Fix this by factoring out a helper to do the
check and properly set the error from nfsd4_validate_stateid.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
[ luis: backported to 3.16:
  - return status immediately in nfsd4_validate_stateid() ]
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

fs/nfsd/nfs4state.c

@@ -3661,10 +3661,17 @@ static __be32 check_stateid_generation(stateid_t *in, stateid_t *ref, bool has_s
 	return nfserr_old_stateid;
 }
 
+static __be32 nfsd4_check_openowner_confirmed(struct nfs4_ol_stateid *ols)
+{
+	if (ols->st_stateowner->so_is_open_owner &&
+	    !(openowner(ols->st_stateowner)->oo_flags & NFS4_OO_CONFIRMED))
+		return nfserr_bad_stateid;
+	return nfs_ok;
+}
+
 static __be32 nfsd4_validate_stateid(struct nfs4_client *cl, stateid_t *stateid)
 {
 	struct nfs4_stid *s;
-	struct nfs4_ol_stateid *ols;
 	__be32 status;
 
 	if (ZERO_STATEID(stateid) || ONE_STATEID(stateid))
@@ -3691,12 +3698,8 @@ static __be32 nfsd4_validate_stateid(struct nfs4_client *cl, stateid_t *stateid)
 		return nfserr_deleg_revoked;
 	case NFS4_OPEN_STID:
 	case NFS4_LOCK_STID:
-		ols = openlockstateid(s);
-		if (ols->st_stateowner->so_is_open_owner
-	    			&& !(openowner(ols->st_stateowner)->oo_flags
-						& NFS4_OO_CONFIRMED))
-			return nfserr_bad_stateid;
-		return nfs_ok;
+		status = nfsd4_check_openowner_confirmed(openlockstateid(s));
+		return status;
 	default:
 		printk("unknown stateid type %x\n", s->sc_type);
 	case NFS4_CLOSED_STID:
@@ -3783,8 +3786,8 @@ nfs4_preprocess_stateid_op(struct net *net, struct nfsd4_compound_state *cstate,
 		status = nfs4_check_fh(current_fh, stp);
 		if (status)
 			goto out;
-		if (stp->st_stateowner->so_is_open_owner
-		    && !(openowner(stp->st_stateowner)->oo_flags & NFS4_OO_CONFIRMED))
+		status = nfsd4_check_openowner_confirmed(stp);
+		if (status)
 			goto out;
 		status = nfs4_check_openmode(stp, flags);
 		if (status)