vn_generic_copy_file_range
error = vn_generic_copy_file_range(ap->a_invp, ap->a_inoffp,
error = vn_generic_copy_file_range(ap->a_invp, ap->a_inoffp,
error = vn_generic_copy_file_range(invpl, inoffp, outvpl,
int vn_generic_copy_file_range(struct vnode *invp, off_t *inoffp,