tn_atime
tp->tn_atime = va->va_atime;
gethrestime(&to->tn_atime);
t->tn_atime = now;
gethrestime(&self->tn_atime);
gethrestime(&tp->tn_atime);
gethrestime(&tp->tn_atime);
tp->tn_atime = now;
gethrestime(&tp->tn_atime);
vap->va_atime = tp->tn_atime;