md/persistent-data/dm-btree-remove.c

29  * Each node may have a left or right sibling.  When decending the spine,
37  *     ==> rebalance(node, right sibling)
39  * [C] No right sibling
42  * [D] Both siblings, total_entries(left, node, right) <= DEL_THRESHOLD
43  *     ==> delete node adding it's contents to left and right
45  * [E] Both siblings, total_entries(left, node, right) > DEL_THRESHOLD
46  *     ==> rebalance(left, node, right)
86 static int node_copy(struct btree_node *left, struct btree_node *right, int shift)
91 	if (value_size != le32_to_cpu(right->header.value_size)) {
105 		       key_ptr(right, 0),
108 		       value_ptr(right, 0),
111 		if (shift > le32_to_cpu(right->header.max_entries)) {
116 		memcpy(key_ptr(right, 0),
119 		memcpy(value_ptr(right, 0),
192 static int shift(struct btree_node *left, struct btree_node *right, int count)
196 	uint32_t nr_right = le32_to_cpu(right->header.nr_entries);
198 	uint32_t r_max_entries = le32_to_cpu(right->header.max_entries);
219 		node_shift(right, count);
220 		r = node_copy(left, right, count);
224 		r = node_copy(left, right, count);
227 		node_shift(right, count);
231 	right->header.nr_entries = cpu_to_le32(nr_right + count);
241 	struct btree_node *right = r->n;
243 	uint32_t nr_right = le32_to_cpu(right->header.nr_entries);
256 		node_copy(left, right, -nr_right);
261 		 * We need to decrement the right block, but not it's
271 		ret = shift(left, right, nr_left - target_left);
274 		*key_ptr(parent, r->index) = right->keys[0];
284 	struct child left, right;
292 	r = init_child(info, vt, parent, left_index + 1, &right);
298 	r = __rebalance2(info, parent, &left, &right);
301 	exit_child(info, &right);
308  * in right, then rebalance2.  This wastes some cpu, but I want something
313 			      struct btree_node *left, struct btree_node *center, struct btree_node *right,
335 		node_shift(right, shift);
336 		node_copy(center, right, shift);
337 		right->header.nr_entries = cpu_to_le32(nr_right + shift);
339 	*key_ptr(parent, r->index) = right->keys[0];
353 			 struct btree_node *left, struct btree_node *center, struct btree_node *right,
376 			ret = shift(left, right, s);
387 		ret = shift(center, right, target_right - nr_right);
394 			ret = shift(center, right, nr_center);
398 			ret = shift(left, right, s);
403 			ret = shift(center, right, s);
414 	*key_ptr(parent, r->index) = right->keys[0];
423 	struct btree_node *right = r->n;
427 	uint32_t nr_right = le32_to_cpu(right->header.nr_entries);
432 	    (center->header.max_entries != right->header.max_entries)) {
438 		return delete_center_node(info, parent, l, c, r, left, center, right,
442 	return redistribute3(info, parent, l, c, r, left, center, right,
451 	struct child left, center, right;
466 	r = init_child(info, vt, parent, left_index + 2, &right);
473 	r = __rebalance3(info, parent, &left, &center, &right);
477 	exit_child(info, &right);