--- ./fs/nfs/inode.c.orig	2005-02-07 22:36:02.000000000 +0100
+++ ./fs/nfs/inode.c	2005-02-07 22:42:10.000000000 +0100
@@ -919,8 +919,9 @@
 {
 	struct nfs_open_context *ctx;
 	struct rpc_cred *cred;
+	struct rpc_groups fsg = { 1, { inode->i_gid } };
 
-	if ((cred = rpcauth_lookupcred(NFS_CLIENT(inode)->cl_auth, NULL, 0)) == NULL)
+	if ((cred = rpcauth_lookupcred(NFS_CLIENT(inode)->cl_auth, &fsg, 0)) == NULL)
 		return -ENOMEM;
 	ctx = alloc_nfs_open_context(filp->f_dentry, cred);
 	if (ctx == NULL)