Btrfs: push_leaf_right
Signed-off-by: Chris Mason <chris.mason@oracle.com>
This commit is contained in:
Chris Mason
David Woodhouse
Родитель
5de08d7d50
Коммит
00ec4c5161
109
fs/btrfs/ctree.c
109
fs/btrfs/ctree.c
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@ -517,6 +517,97 @@ int leaf_space_used(struct leaf *l, int start, int nr)
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return data_len;
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}
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/*
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* push some data in the path leaf to the right, trying to free up at
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* least data_size bytes. returns zero if the push worked, nonzero otherwise
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*/
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int push_leaf_right(struct ctree_root *root, struct ctree_path *path,
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int data_size)
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{
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struct tree_buffer *left_buf = path->nodes[0];
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struct leaf *left = &left_buf->leaf;
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struct leaf *right;
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struct tree_buffer *right_buf;
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struct tree_buffer *upper;
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int slot;
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int i;
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int free_space;
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int push_space = 0;
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int push_items = 0;
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struct item *item;
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slot = path->slots[1];
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if (!path->nodes[1]) {
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return 1;
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}
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upper = path->nodes[1];
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if (slot >= upper->node.header.nritems - 1) {
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return 1;
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}
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right_buf = read_tree_block(root, upper->node.blockptrs[slot + 1]);
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right = &right_buf->leaf;
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free_space = leaf_free_space(right);
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if (free_space < data_size + sizeof(struct item)) {
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tree_block_release(root, right_buf);
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return 1;
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}
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for (i = left->header.nritems - 1; i >= 0; i--) {
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item = left->items + i;
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if (path->slots[0] == i)
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push_space += data_size + sizeof(*item);
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if (item->size + sizeof(*item) + push_space > free_space)
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break;
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push_items++;
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push_space += item->size + sizeof(*item);
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}
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if (push_items == 0) {
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tree_block_release(root, right_buf);
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return 1;
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}
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/* push left to right */
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push_space = left->items[left->header.nritems - push_items].offset +
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left->items[left->header.nritems - push_items].size;
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push_space -= leaf_data_end(left);
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/* make room in the right data area */
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memmove(right->data + leaf_data_end(right) - push_space,
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right->data + leaf_data_end(right),
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LEAF_DATA_SIZE - leaf_data_end(right));
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/* copy from the left data area */
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memcpy(right->data + LEAF_DATA_SIZE - push_space,
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left->data + leaf_data_end(left),
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push_space);
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memmove(right->items + push_items, right->items,
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right->header.nritems * sizeof(struct item));
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/* copy the items from left to right */
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memcpy(right->items, left->items + left->header.nritems - push_items,
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push_items * sizeof(struct item));
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/* update the item pointers */
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right->header.nritems += push_items;
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push_space = LEAF_DATA_SIZE;
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for (i = 0; i < right->header.nritems; i++) {
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right->items[i].offset = push_space - right->items[i].size;
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push_space = right->items[i].offset;
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}
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left->header.nritems -= push_items;
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write_tree_block(root, left_buf);
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write_tree_block(root, right_buf);
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memcpy(upper->node.keys + slot + 1,
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&right->items[0].key, sizeof(struct key));
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write_tree_block(root, upper);
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/* then fixup the leaf pointer in the path */
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// FIXME use nritems in here somehow
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if (path->slots[0] >= left->header.nritems) {
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path->slots[0] -= left->header.nritems;
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tree_block_release(root, path->nodes[0]);
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path->nodes[0] = right_buf;
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path->slots[1] += 1;
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} else {
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tree_block_release(root, right_buf);
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}
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return 0;
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}
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/*
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* push some data in the path leaf to the left, trying to free up at
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* least data_size bytes. returns zero if the push worked, nonzero otherwise
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@ -631,7 +722,8 @@ int split_leaf(struct ctree_root *root, struct ctree_path *path, int data_size)
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int i;
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int ret;
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if (push_leaf_left(root, path, data_size) == 0) {
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if (push_leaf_left(root, path, data_size) == 0 ||
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push_leaf_right(root, path, data_size) == 0) {
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l_buf = path->nodes[0];
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l = &l_buf->leaf;
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if (leaf_free_space(l) >= sizeof(struct item) + data_size)
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@ -875,6 +967,8 @@ int del_item(struct ctree_root *root, struct ctree_path *path)
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slot = path->slots[1];
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leaf_buf->count++;
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push_leaf_left(root, path, 1);
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if (leaf->header.nritems)
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push_leaf_right(root, path, 1);
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if (leaf->header.nritems == 0) {
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u64 blocknr = leaf_buf->blocknr;
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path->slots[1] = slot;
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@ -929,7 +1023,7 @@ int next_leaf(struct ctree_root *root, struct ctree_path *path)
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/* for testing only */
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int next_key(int i, int max_key) {
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return rand() % max_key;
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// return i;
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//return i;
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}
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int main() {
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@ -958,7 +1052,7 @@ int main() {
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// num = i;
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sprintf(buf, "string-%d", num);
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if (i % 10000 == 0)
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printf("insert %d:%d\n", num, i);
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fprintf(stderr, "insert %d:%d\n", num, i);
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ins.objectid = num;
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ins.offset = 0;
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ins.flags = 0;
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@ -978,7 +1072,7 @@ int main() {
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ins.objectid = num;
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init_path(&path);
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if (i % 10000 == 0)
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printf("search %d:%d\n", num, i);
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fprintf(stderr, "search %d:%d\n", num, i);
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ret = search_slot(root, &ins, &path, 0);
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if (ret) {
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print_tree(root, root->node);
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@ -1004,7 +1098,7 @@ int main() {
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ret = search_slot(root, &ins, &path, -1);
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if (!ret) {
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if (i % 10000 == 0)
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printf("del %d:%d\n", num, i);
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fprintf(stderr, "del %d:%d\n", num, i);
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ret = del_item(root, &path);
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if (ret != 0)
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BUG();
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@ -1022,7 +1116,7 @@ int main() {
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sprintf(buf, "string-%d", num);
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ins.objectid = num;
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if (i % 10000 == 0)
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printf("insert %d:%d\n", num, i);
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fprintf(stderr, "insert %d:%d\n", num, i);
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ret = insert_item(root, &ins, buf, strlen(buf));
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if (!ret)
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tree_size++;
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@ -1038,7 +1132,7 @@ int main() {
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ins.objectid = num;
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init_path(&path);
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if (i % 10000 == 0)
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printf("search %d:%d\n", num, i);
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fprintf(stderr, "search %d:%d\n", num, i);
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ret = search_slot(root, &ins, &path, 0);
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if (ret) {
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print_tree(root, root->node);
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@ -1082,6 +1176,7 @@ int main() {
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}
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printf("tree size is now %d\n", tree_size);
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printf("map tree\n");
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print_tree(root->extent_root, root->extent_root->node);
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write_ctree_super(root, &super);
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close_ctree(root);
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return 0;
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