+static int free_dev_extent_item(struct btrfs_trans_handle *trans,
+ struct btrfs_fs_info *fs_info,
+ u64 devid, u64 dev_offset)
+{
+ struct btrfs_root *root = fs_info->dev_root;
+ struct btrfs_path *path;
+ struct btrfs_key key;
+ int ret;
+
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+
+ key.objectid = devid;
+ key.type = BTRFS_DEV_EXTENT_KEY;
+ key.offset = dev_offset;
+
+ ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
+ if (ret < 0)
+ goto out;
+ if (ret > 0) {
+ ret = -ENOENT;
+ goto out;
+ }
+
+ ret = btrfs_del_item(trans, root, path);
+out:
+ btrfs_free_path(path);
+ return ret;
+}
+
+static int free_chunk_dev_extent_items(struct btrfs_trans_handle *trans,
+ struct btrfs_fs_info *fs_info,
+ u64 chunk_offset)
+{
+ struct btrfs_chunk *chunk = NULL;
+ struct btrfs_root *root= fs_info->chunk_root;
+ struct btrfs_path *path;
+ struct btrfs_key key;
+ u16 num_stripes;
+ int i;
+ int ret;
+
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+
+ key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
+ key.type = BTRFS_CHUNK_ITEM_KEY;
+ key.offset = chunk_offset;
+
+ ret = btrfs_search_slot(trans, root, &key, path, 0, 0);
+ if (ret < 0)
+ goto out;
+ if (ret > 0) {
+ ret = -ENOENT;
+ goto out;
+ }
+ chunk = btrfs_item_ptr(path->nodes[0], path->slots[0],
+ struct btrfs_chunk);
+ num_stripes = btrfs_chunk_num_stripes(path->nodes[0], chunk);
+ for (i = 0; i < num_stripes; i++) {
+ ret = free_dev_extent_item(trans, fs_info,
+ btrfs_stripe_devid_nr(path->nodes[0], chunk, i),
+ btrfs_stripe_offset_nr(path->nodes[0], chunk, i));
+ if (ret < 0)
+ goto out;
+ }
+out:
+ btrfs_free_path(path);
+ return ret;
+}
+
+static int free_system_chunk_item(struct btrfs_super_block *super,
+ struct btrfs_key *key)
+{
+ struct btrfs_disk_key *disk_key;
+ struct btrfs_key cpu_key;
+ u32 array_size = btrfs_super_sys_array_size(super);
+ char *ptr = (char *)super->sys_chunk_array;
+ int cur = 0;
+ int ret = -ENOENT;
+
+ while (cur < btrfs_super_sys_array_size(super)) {
+ struct btrfs_chunk *chunk;
+ u32 num_stripes;
+ u32 chunk_len;
+
+ disk_key = (struct btrfs_disk_key *)(ptr + cur);
+ btrfs_disk_key_to_cpu(&cpu_key, disk_key);
+ if (cpu_key.type != BTRFS_CHUNK_ITEM_KEY) {
+ /* just in case */
+ ret = -EIO;
+ goto out;
+ }
+
+ chunk = (struct btrfs_chunk *)(ptr + cur + sizeof(*disk_key));
+ num_stripes = btrfs_stack_chunk_num_stripes(chunk);
+ chunk_len = btrfs_chunk_item_size(num_stripes) +
+ sizeof(*disk_key);
+
+ if (key->objectid == cpu_key.objectid &&
+ key->offset == cpu_key.offset &&
+ key->type == cpu_key.type) {
+ memmove(ptr + cur, ptr + cur + chunk_len,
+ array_size - cur - chunk_len);
+ array_size -= chunk_len;
+ btrfs_set_super_sys_array_size(super, array_size);
+ ret = 0;
+ goto out;
+ }
+
+ cur += chunk_len;
+ }
+out:
+ return ret;
+}
+
+static int free_chunk_item(struct btrfs_trans_handle *trans,
+ struct btrfs_fs_info *fs_info,
+ u64 bytenr)
+{
+ struct btrfs_path *path;
+ struct btrfs_key key;
+ struct btrfs_root *root = fs_info->chunk_root;
+ struct btrfs_chunk *chunk;
+ u64 chunk_type;
+ int ret;
+
+ key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
+ key.offset = bytenr;
+ key.type = BTRFS_CHUNK_ITEM_KEY;
+
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+
+ ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
+ if (ret > 0) {
+ ret = -ENOENT;
+ goto out;
+ }
+ if (ret < 0)
+ goto out;
+ chunk = btrfs_item_ptr(path->nodes[0], path->slots[0],
+ struct btrfs_chunk);
+ chunk_type = btrfs_chunk_type(path->nodes[0], chunk);
+
+ ret = btrfs_del_item(trans, root, path);
+ if (ret < 0)
+ goto out;
+
+ if (chunk_type & BTRFS_BLOCK_GROUP_SYSTEM)
+ ret = free_system_chunk_item(fs_info->super_copy, &key);
+out:
+ btrfs_free_path(path);
+ return ret;
+}
+
+static u64 get_dev_extent_len(struct map_lookup *map)
+{
+ int div;
+
+ switch (map->type & BTRFS_BLOCK_GROUP_PROFILE_MASK) {
+ case 0: /* Single */
+ case BTRFS_BLOCK_GROUP_DUP:
+ case BTRFS_BLOCK_GROUP_RAID1:
+ div = 1;
+ break;
+ case BTRFS_BLOCK_GROUP_RAID5:
+ div = (map->num_stripes - 1);
+ break;
+ case BTRFS_BLOCK_GROUP_RAID6:
+ div = (map->num_stripes - 2);
+ break;
+ case BTRFS_BLOCK_GROUP_RAID10:
+ div = (map->num_stripes / map->sub_stripes);
+ break;
+ default:
+ /* normally, read chunk security hook should handled it */
+ BUG_ON(1);
+ }
+ return map->ce.size / div;
+}
+
+/* free block group/chunk related caches */
+static int free_block_group_cache(struct btrfs_trans_handle *trans,
+ struct btrfs_fs_info *fs_info,
+ u64 bytenr, u64 len)
+{
+ struct btrfs_block_group_cache *cache;
+ struct cache_extent *ce;
+ struct map_lookup *map;
+ int ret;
+ int i;
+ u64 flags;
+
+ /* Free block group cache first */
+ cache = btrfs_lookup_block_group(fs_info, bytenr);
+ if (!cache)
+ return -ENOENT;
+ flags = cache->flags;
+ if (cache->free_space_ctl) {
+ btrfs_remove_free_space_cache(cache);
+ kfree(cache->free_space_ctl);
+ }
+ clear_extent_bits(&fs_info->block_group_cache, bytenr, bytenr + len - 1,
+ (unsigned int)-1);
+ ret = free_space_info(fs_info, flags, len, 0, NULL);
+ if (ret < 0)
+ goto out;
+ kfree(cache);
+
+ /* Then free mapping info and dev usage info */
+ ce = search_cache_extent(&fs_info->mapping_tree.cache_tree, bytenr);
+ if (!ce || ce->start != bytenr) {
+ ret = -ENOENT;
+ goto out;
+ }
+ map = container_of(ce, struct map_lookup, ce);
+ for (i = 0; i < map->num_stripes; i++) {
+ struct btrfs_device *device;
+
+ device = map->stripes[i].dev;
+ device->bytes_used -= get_dev_extent_len(map);
+ ret = btrfs_update_device(trans, device);
+ if (ret < 0)
+ goto out;
+ }
+ remove_cache_extent(&fs_info->mapping_tree.cache_tree, ce);
+ free(map);
+out:
+ return ret;
+}
+
+int btrfs_free_block_group(struct btrfs_trans_handle *trans,
+ struct btrfs_fs_info *fs_info, u64 bytenr, u64 len)
+{
+ struct btrfs_root *extent_root = fs_info->extent_root;
+ struct btrfs_path *path;
+ struct btrfs_block_group_item *bgi;
+ struct btrfs_key key;
+ int ret = 0;
+
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+
+ key.objectid = bytenr;
+ key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
+ key.offset = len;
+
+ /* Double check the block group to ensure it's empty */
+ ret = btrfs_search_slot(trans, extent_root, &key, path, 0, 0);
+ if (ret > 0) {
+ ret = -ENONET;
+ goto out;
+ }
+ if (ret < 0)
+ goto out;
+
+ bgi = btrfs_item_ptr(path->nodes[0], path->slots[0],
+ struct btrfs_block_group_item);
+ if (btrfs_disk_block_group_used(path->nodes[0], bgi)) {
+ fprintf(stderr,
+ "WARNING: block group [%llu,%llu) is not empty\n",
+ bytenr, bytenr + len);
+ ret = -EINVAL;
+ goto out;
+ }
+ btrfs_release_path(path);
+
+ /*
+ * Now pin all space in the block group, to prevent further transaction
+ * allocate space from it.
+ * Every operation needs a transaction must be in the range.
+ */
+ btrfs_pin_extent(fs_info, bytenr, len);
+
+ /* delete block group item and chunk item */
+ ret = free_block_group_item(trans, fs_info, bytenr, len);
+ if (ret < 0) {
+ fprintf(stderr,
+ "failed to free block group item for [%llu,%llu)\n",
+ bytenr, bytenr + len);
+ btrfs_unpin_extent(fs_info, bytenr, len);
+ goto out;
+ }
+
+ ret = free_chunk_dev_extent_items(trans, fs_info, bytenr);
+ if (ret < 0) {
+ fprintf(stderr,
+ "failed to dev extents belongs to [%llu,%llu)\n",
+ bytenr, bytenr + len);
+ btrfs_unpin_extent(fs_info, bytenr, len);
+ goto out;
+ }
+ ret = free_chunk_item(trans, fs_info, bytenr);
+ if (ret < 0) {
+ fprintf(stderr,
+ "failed to free chunk for [%llu,%llu)\n",
+ bytenr, bytenr + len);
+ btrfs_unpin_extent(fs_info, bytenr, len);
+ goto out;
+ }
+
+ /* Now release the block_group_cache */
+ ret = free_block_group_cache(trans, fs_info, bytenr, len);
+ btrfs_unpin_extent(fs_info, bytenr, len);
+
+out:
+ btrfs_free_path(path);
+ return ret;
+}
+