diff options
Diffstat (limited to 'ctree.c')
| -rw-r--r-- | ctree.c | 125 |
1 files changed, 120 insertions, 5 deletions
@@ -1114,7 +1114,8 @@ again: if (ret && slot > 0) slot -= 1; p->slots[level] = slot; - if (ins_len > 0 && btrfs_header_nritems(b) >= + if ((p->search_for_split || ins_len > 0) && + btrfs_header_nritems(b) >= BTRFS_NODEPTRS_PER_BLOCK(root) - 3) { int sret = split_node(trans, root, p, level); BUG_ON(sret > 0); @@ -1949,11 +1950,11 @@ static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root int num_doubles = 0; struct btrfs_disk_key disk_key; - if (extend) + if (extend && data_size) space_needed = data_size; /* first try to make some room by pushing left and right */ - if (ins_key->type != BTRFS_DIR_ITEM_KEY) { + if (data_size && ins_key->type != BTRFS_DIR_ITEM_KEY) { wret = push_leaf_right(trans, root, path, data_size, 0); if (wret < 0) { return wret; @@ -2031,7 +2032,7 @@ again: } else { if (leaf_space_used(l, 0, mid + 1) + space_needed > BTRFS_LEAF_DATA_SIZE(root)) { - if (!extend && slot == 0) { + if (!extend && data_size && slot == 0) { btrfs_cpu_key_to_disk(&disk_key, ins_key); btrfs_set_header_nritems(right, 0); wret = insert_ptr(trans, root, path, @@ -2050,7 +2051,7 @@ again: ret = wret; } return ret; - } else if (extend && slot == 0) { + } else if ((extend || !data_size) && slot == 0) { mid = 1; } else { mid = slot; @@ -2117,6 +2118,120 @@ again: return ret; } +/* + * This function splits a single item into two items, + * giving 'new_key' to the new item and splitting the + * old one at split_offset (from the start of the item). + * + * The path may be released by this operation. After + * the split, the path is pointing to the old item. The + * new item is going to be in the same node as the old one. + * + * Note, the item being split must be smaller enough to live alone on + * a tree block with room for one extra struct btrfs_item + * + * This allows us to split the item in place, keeping a lock on the + * leaf the entire time. + */ +int btrfs_split_item(struct btrfs_trans_handle *trans, + struct btrfs_root *root, + struct btrfs_path *path, + struct btrfs_key *new_key, + unsigned long split_offset) +{ + u32 item_size; + struct extent_buffer *leaf; + struct btrfs_key orig_key; + struct btrfs_item *item; + struct btrfs_item *new_item; + int ret = 0; + int slot; + u32 nritems; + u32 orig_offset; + struct btrfs_disk_key disk_key; + char *buf; + + leaf = path->nodes[0]; + btrfs_item_key_to_cpu(leaf, &orig_key, path->slots[0]); + if (btrfs_leaf_free_space(root, leaf) >= sizeof(struct btrfs_item)) + goto split; + + item_size = btrfs_item_size_nr(leaf, path->slots[0]); + btrfs_release_path(root, path); + + path->search_for_split = 1; + + ret = btrfs_search_slot(trans, root, &orig_key, path, 0, 1); + path->search_for_split = 0; + + /* if our item isn't there or got smaller, return now */ + if (ret != 0 || item_size != btrfs_item_size_nr(path->nodes[0], + path->slots[0])) { + return -EAGAIN; + } + + ret = split_leaf(trans, root, &orig_key, path, 0, 0); + BUG_ON(ret); + + BUG_ON(btrfs_leaf_free_space(root, leaf) < sizeof(struct btrfs_item)); + leaf = path->nodes[0]; + +split: + item = btrfs_item_nr(leaf, path->slots[0]); + orig_offset = btrfs_item_offset(leaf, item); + item_size = btrfs_item_size(leaf, item); + + + buf = kmalloc(item_size, GFP_NOFS); + read_extent_buffer(leaf, buf, btrfs_item_ptr_offset(leaf, + path->slots[0]), item_size); + slot = path->slots[0] + 1; + leaf = path->nodes[0]; + + nritems = btrfs_header_nritems(leaf); + + if (slot != nritems) { + /* shift the items */ + memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + 1), + btrfs_item_nr_offset(slot), + (nritems - slot) * sizeof(struct btrfs_item)); + + } + + btrfs_cpu_key_to_disk(&disk_key, new_key); + btrfs_set_item_key(leaf, &disk_key, slot); + + new_item = btrfs_item_nr(leaf, slot); + + btrfs_set_item_offset(leaf, new_item, orig_offset); + btrfs_set_item_size(leaf, new_item, item_size - split_offset); + + btrfs_set_item_offset(leaf, item, + orig_offset + item_size - split_offset); + btrfs_set_item_size(leaf, item, split_offset); + + btrfs_set_header_nritems(leaf, nritems + 1); + + /* write the data for the start of the original item */ + write_extent_buffer(leaf, buf, + btrfs_item_ptr_offset(leaf, path->slots[0]), + split_offset); + + /* write the data for the new item */ + write_extent_buffer(leaf, buf + split_offset, + btrfs_item_ptr_offset(leaf, slot), + item_size - split_offset); + btrfs_mark_buffer_dirty(leaf); + + ret = 0; + if (btrfs_leaf_free_space(root, leaf) < 0) { + btrfs_print_leaf(root, leaf); + BUG(); + } + kfree(buf); + return ret; +} + int btrfs_truncate_item(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_path *path, |