MF_MOUNTPOINT
dfnp->fn_flags |= MF_MOUNTPOINT;
if (dfnp->fn_flags & MF_MOUNTPOINT) {
dfnp->fn_flags &= ~MF_MOUNTPOINT;
ASSERT((dfnp->fn_flags & MF_MOUNTPOINT) == 0);
if ((fnp->fn_flags & MF_MOUNTPOINT) &&