NFS4_CDFC4_BACK
if (c->cn_flags & NFS4_CDFC4_BACK)
dir |= NFS4_CDFC4_BACK;
case NFS4_CDFC4_BACK:
c->cn_flags != NFS4_CDFC4_BACK)
bcts->dir == NFS4_CDFC4_BACK)
conn->cn_flags |= NFS4_CDFC4_BACK;