/* Return the highest key that you could lookup from the n'th node on level l of the btree.  */
static sector_t high(struct dm_table *t, unsigned int l, unsigned int n)
/* Return the highest key that you could lookup from the n'th node on level l of the btree.  */
static sector_t high(struct dm_table *t, unsigned int l, unsigned int n)
{
	for (; l < t->depth - 1; l++)
		n = get_child(n, CHILDREN_PER_NODE - 1);
	if (n >= t->counts[l])
		return (sector_t) - 1;
	return get_node(t, l, n)[KEYS_PER_NODE - 1];
}