25  * Each node may have a left or right sibling.  When decending the spine,
33  *     ==> rebalance(node, right sibling)
35  * [C] No right sibling
38  * [D] Both siblings, total_entries(left, node, right) <= DEL_THRESHOLD
39  *     ==> delete node adding it's contents to left and right
41  * [E] Both siblings, total_entries(left, node, right) > DEL_THRESHOLD
42  *     ==> rebalance(left, node, right)
82 static void node_copy(struct btree_node *left, struct btree_node *right, int shift)  in node_copy()  argument
86 	BUG_ON(value_size != le32_to_cpu(right->header.value_size));  in node_copy()
92 		       key_ptr(right, 0),  in node_copy()
95 		       value_ptr(right, 0),  in node_copy()
98 		BUG_ON(shift > le32_to_cpu(right->header.max_entries));  in node_copy()
99 		memcpy(key_ptr(right, 0),  in node_copy()
102 		memcpy(value_ptr(right, 0),  in node_copy()
173 static void shift(struct btree_node *left, struct btree_node *right, int count)  in shift()  argument
176 	uint32_t nr_right = le32_to_cpu(right->header.nr_entries);  in shift()
178 	uint32_t r_max_entries = le32_to_cpu(right->header.max_entries);  in shift()
188 		node_shift(right, count);  in shift()
189 		node_copy(left, right, count);  in shift()
191 		node_copy(left, right, count);  in shift()
192 		node_shift(right, count);  in shift()
196 	right->header.nr_entries = cpu_to_le32(nr_right + count);  in shift()
203 	struct btree_node *right = r->n;  in __rebalance2()  local
205 	uint32_t nr_right = le32_to_cpu(right->header.nr_entries);  in __rebalance2()
212 		node_copy(left, right, -nr_right);  in __rebalance2()
217 		 * We need to decrement the right block, but not it's  in __rebalance2()
226 		shift(left, right, nr_left - target_left);  in __rebalance2()
227 		*key_ptr(parent, r->index) = right->keys[0];  in __rebalance2()
236 	struct child left, right;  in rebalance2()  local
244 	r = init_child(info, vt, parent, left_index + 1, &right);  in rebalance2()
250 	__rebalance2(info, parent, &left, &right);  in rebalance2()
253 	exit_child(info, &right);  in rebalance2()
260  * in right, then rebalance2.  This wastes some cpu, but I want something
265 			       struct btree_node *left, struct btree_node *center, struct btree_node *right,  in delete_center_node()  argument
278 		node_shift(right, shift);  in delete_center_node()
279 		node_copy(center, right, shift);  in delete_center_node()
280 		right->header.nr_entries = cpu_to_le32(nr_right + shift);  in delete_center_node()
282 	*key_ptr(parent, r->index) = right->keys[0];  in delete_center_node()
296 			  struct btree_node *left, struct btree_node *center, struct btree_node *right,  in redistribute3()  argument
316 			shift(left, right, s);  in redistribute3()
321 		shift(center, right, target_right - nr_right);  in redistribute3()
327 			shift(center, right, nr_center);  in redistribute3()
329 			shift(left, right, s);  in redistribute3()
332 			shift(center, right, s);  in redistribute3()
338 	*key_ptr(parent, r->index) = right->keys[0];  in redistribute3()
346 	struct btree_node *right = r->n;  in __rebalance3()  local
350 	uint32_t nr_right = le32_to_cpu(right->header.nr_entries);  in __rebalance3()
355 	BUG_ON(center->header.max_entries != right->header.max_entries);  in __rebalance3()
358 		delete_center_node(info, parent, l, c, r, left, center, right,  in __rebalance3()
361 		redistribute3(info, parent, l, c, r, left, center, right,  in __rebalance3()
370 	struct child left, center, right;  in rebalance3()  local
385 	r = init_child(info, vt, parent, left_index + 2, &right);  in rebalance3()
392 	__rebalance3(info, parent, &left, &center, &right);  in rebalance3()
396 	exit_child(info, &right);  in rebalance3()