Пример #1
0
static noinline int create_subvol(struct btrfs_root *root,
				  struct dentry *dentry,
				  char *name, int namelen)
{
	struct btrfs_trans_handle *trans;
	struct btrfs_key key;
	struct btrfs_root_item root_item;
	struct btrfs_inode_item *inode_item;
	struct extent_buffer *leaf;
	struct btrfs_root *new_root;
	struct inode *dir = dentry->d_parent->d_inode;
	int ret;
	int err;
	u64 objectid;
	u64 new_dirid = BTRFS_FIRST_FREE_OBJECTID;
	u64 index = 0;

	ret = btrfs_find_free_objectid(NULL, root->fs_info->tree_root,
				       0, &objectid);
	if (ret)
		return ret;
	/*
	 * 1 - inode item
	 * 2 - refs
	 * 1 - root item
	 * 2 - dir items
	 */
	trans = btrfs_start_transaction(root, 6);
	if (IS_ERR(trans))
		return PTR_ERR(trans);

	leaf = btrfs_alloc_free_block(trans, root, root->leafsize,
				      0, objectid, NULL, 0, 0, 0);
	if (IS_ERR(leaf)) {
		ret = PTR_ERR(leaf);
		goto fail;
	}

	memset_extent_buffer(leaf, 0, 0, sizeof(struct btrfs_header));
	btrfs_set_header_bytenr(leaf, leaf->start);
	btrfs_set_header_generation(leaf, trans->transid);
	btrfs_set_header_backref_rev(leaf, BTRFS_MIXED_BACKREF_REV);
	btrfs_set_header_owner(leaf, objectid);

	write_extent_buffer(leaf, root->fs_info->fsid,
			    (unsigned long)btrfs_header_fsid(leaf),
			    BTRFS_FSID_SIZE);
	write_extent_buffer(leaf, root->fs_info->chunk_tree_uuid,
			    (unsigned long)btrfs_header_chunk_tree_uuid(leaf),
			    BTRFS_UUID_SIZE);
	btrfs_mark_buffer_dirty(leaf);

	inode_item = &root_item.inode;
	memset(inode_item, 0, sizeof(*inode_item));
	inode_item->generation = cpu_to_le64(1);
	inode_item->size = cpu_to_le64(3);
	inode_item->nlink = cpu_to_le32(1);
	inode_item->nbytes = cpu_to_le64(root->leafsize);
	inode_item->mode = cpu_to_le32(S_IFDIR | 0755);

	root_item.flags = 0;
	root_item.byte_limit = 0;
	inode_item->flags = cpu_to_le64(BTRFS_INODE_ROOT_ITEM_INIT);

	btrfs_set_root_bytenr(&root_item, leaf->start);
	btrfs_set_root_generation(&root_item, trans->transid);
	btrfs_set_root_level(&root_item, 0);
	btrfs_set_root_refs(&root_item, 1);
	btrfs_set_root_used(&root_item, leaf->len);
	btrfs_set_root_last_snapshot(&root_item, 0);

	memset(&root_item.drop_progress, 0, sizeof(root_item.drop_progress));
	root_item.drop_level = 0;

	btrfs_tree_unlock(leaf);
	free_extent_buffer(leaf);
	leaf = NULL;

	btrfs_set_root_dirid(&root_item, new_dirid);

	key.objectid = objectid;
	key.offset = 0;
	btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
	ret = btrfs_insert_root(trans, root->fs_info->tree_root, &key,
				&root_item);
	if (ret)
		goto fail;

	key.offset = (u64)-1;
	new_root = btrfs_read_fs_root_no_name(root->fs_info, &key);
	BUG_ON(IS_ERR(new_root));

	btrfs_record_root_in_trans(trans, new_root);

	ret = btrfs_create_subvol_root(trans, new_root, new_dirid,
				       BTRFS_I(dir)->block_group);
	/*
	 * insert the directory item
	 */
	ret = btrfs_set_inode_index(dir, &index);
	BUG_ON(ret);

	ret = btrfs_insert_dir_item(trans, root,
				    name, namelen, dir->i_ino, &key,
				    BTRFS_FT_DIR, index);
	if (ret)
		goto fail;

	btrfs_i_size_write(dir, dir->i_size + namelen * 2);
	ret = btrfs_update_inode(trans, root, dir);
	BUG_ON(ret);

	ret = btrfs_add_root_ref(trans, root->fs_info->tree_root,
				 objectid, root->root_key.objectid,
				 dir->i_ino, index, name, namelen);

	BUG_ON(ret);

	d_instantiate(dentry, btrfs_lookup_dentry(dir, dentry));
fail:
	err = btrfs_commit_transaction(trans, root);
	if (err && !ret)
		ret = err;
	return ret;
}
Пример #2
0
int make_btrfs(int fd, const char *device, const char *label,
	       u64 blocks[7], u64 num_bytes, u32 nodesize,
	       u32 leafsize, u32 sectorsize, u32 stripesize, u64 features)
{
	struct btrfs_super_block super;
	struct extent_buffer *buf;
	struct btrfs_root_item root_item;
	struct btrfs_disk_key disk_key;
	struct btrfs_extent_item *extent_item;
	struct btrfs_inode_item *inode_item;
	struct btrfs_chunk *chunk;
	struct btrfs_dev_item *dev_item;
	struct btrfs_dev_extent *dev_extent;
	u8 chunk_tree_uuid[BTRFS_UUID_SIZE];
	u8 *ptr;
	int i;
	int ret;
	u32 itemoff;
	u32 nritems = 0;
	u64 first_free;
	u64 ref_root;
	u32 array_size;
	u32 item_size;
	int skinny_metadata = !!(features &
				 BTRFS_FEATURE_INCOMPAT_SKINNY_METADATA);

	first_free = BTRFS_SUPER_INFO_OFFSET + sectorsize * 2 - 1;
	first_free &= ~((u64)sectorsize - 1);

	memset(&super, 0, sizeof(super));

	num_bytes = (num_bytes / sectorsize) * sectorsize;
	uuid_generate(super.fsid);
	uuid_generate(super.dev_item.uuid);
	uuid_generate(chunk_tree_uuid);

	btrfs_set_super_bytenr(&super, blocks[0]);
	btrfs_set_super_num_devices(&super, 1);
	btrfs_set_super_magic(&super, BTRFS_MAGIC);
	btrfs_set_super_generation(&super, 1);
	btrfs_set_super_root(&super, blocks[1]);
	btrfs_set_super_chunk_root(&super, blocks[3]);
	btrfs_set_super_total_bytes(&super, num_bytes);
	btrfs_set_super_bytes_used(&super, 6 * leafsize);
	btrfs_set_super_sectorsize(&super, sectorsize);
	btrfs_set_super_leafsize(&super, leafsize);
	btrfs_set_super_nodesize(&super, nodesize);
	btrfs_set_super_stripesize(&super, stripesize);
	btrfs_set_super_csum_type(&super, BTRFS_CSUM_TYPE_CRC32);
	btrfs_set_super_chunk_root_generation(&super, 1);
	btrfs_set_super_cache_generation(&super, -1);
	btrfs_set_super_incompat_flags(&super, features);
	if (label)
		strncpy(super.label, label, BTRFS_LABEL_SIZE - 1);

	buf = malloc(sizeof(*buf) + max(sectorsize, leafsize));

	/* create the tree of root objects */
	memset(buf->data, 0, leafsize);
	buf->len = leafsize;
	btrfs_set_header_bytenr(buf, blocks[1]);
	btrfs_set_header_nritems(buf, 4);
	btrfs_set_header_generation(buf, 1);
	btrfs_set_header_backref_rev(buf, BTRFS_MIXED_BACKREF_REV);
	btrfs_set_header_owner(buf, BTRFS_ROOT_TREE_OBJECTID);
	write_extent_buffer(buf, super.fsid, btrfs_header_fsid(),
			    BTRFS_FSID_SIZE);

	write_extent_buffer(buf, chunk_tree_uuid, (unsigned long)
			    btrfs_header_chunk_tree_uuid(buf),
			    BTRFS_UUID_SIZE);

	/* create the items for the root tree */
	memset(&root_item, 0, sizeof(root_item));
	inode_item = &root_item.inode;
	btrfs_set_stack_inode_generation(inode_item, 1);
	btrfs_set_stack_inode_size(inode_item, 3);
	btrfs_set_stack_inode_nlink(inode_item, 1);
	btrfs_set_stack_inode_nbytes(inode_item, leafsize);
	btrfs_set_stack_inode_mode(inode_item, S_IFDIR | 0755);
	btrfs_set_root_refs(&root_item, 1);
	btrfs_set_root_used(&root_item, leafsize);
	btrfs_set_root_generation(&root_item, 1);

	memset(&disk_key, 0, sizeof(disk_key));
	btrfs_set_disk_key_type(&disk_key, BTRFS_ROOT_ITEM_KEY);
	btrfs_set_disk_key_offset(&disk_key, 0);
	nritems = 0;

	itemoff = __BTRFS_LEAF_DATA_SIZE(leafsize) - sizeof(root_item);
	btrfs_set_root_bytenr(&root_item, blocks[2]);
	btrfs_set_disk_key_objectid(&disk_key, BTRFS_EXTENT_TREE_OBJECTID);
	btrfs_set_item_key(buf, &disk_key, nritems);
	btrfs_set_item_offset(buf, btrfs_item_nr(nritems), itemoff);
	btrfs_set_item_size(buf, btrfs_item_nr(nritems),
			    sizeof(root_item));
	write_extent_buffer(buf, &root_item, btrfs_item_ptr_offset(buf,
			    nritems), sizeof(root_item));
	nritems++;

	itemoff = itemoff - sizeof(root_item);
	btrfs_set_root_bytenr(&root_item, blocks[4]);
	btrfs_set_disk_key_objectid(&disk_key, BTRFS_DEV_TREE_OBJECTID);
	btrfs_set_item_key(buf, &disk_key, nritems);
	btrfs_set_item_offset(buf, btrfs_item_nr(nritems), itemoff);
	btrfs_set_item_size(buf, btrfs_item_nr(nritems),
			    sizeof(root_item));
	write_extent_buffer(buf, &root_item,
			    btrfs_item_ptr_offset(buf, nritems),
			    sizeof(root_item));
	nritems++;

	itemoff = itemoff - sizeof(root_item);
	btrfs_set_root_bytenr(&root_item, blocks[5]);
	btrfs_set_disk_key_objectid(&disk_key, BTRFS_FS_TREE_OBJECTID);
	btrfs_set_item_key(buf, &disk_key, nritems);
	btrfs_set_item_offset(buf, btrfs_item_nr(nritems), itemoff);
	btrfs_set_item_size(buf, btrfs_item_nr(nritems),
			    sizeof(root_item));
	write_extent_buffer(buf, &root_item,
			    btrfs_item_ptr_offset(buf, nritems),
			    sizeof(root_item));
	nritems++;

	itemoff = itemoff - sizeof(root_item);
	btrfs_set_root_bytenr(&root_item, blocks[6]);
	btrfs_set_disk_key_objectid(&disk_key, BTRFS_CSUM_TREE_OBJECTID);
	btrfs_set_item_key(buf, &disk_key, nritems);
	btrfs_set_item_offset(buf, btrfs_item_nr(nritems), itemoff);
	btrfs_set_item_size(buf, btrfs_item_nr(nritems),
			    sizeof(root_item));
	write_extent_buffer(buf, &root_item,
			    btrfs_item_ptr_offset(buf, nritems),
			    sizeof(root_item));
	nritems++;


	csum_tree_block_size(buf, BTRFS_CRC32_SIZE, 0);
	ret = pwrite(fd, buf->data, leafsize, blocks[1]);
	if (ret != leafsize) {
		ret = (ret < 0 ? -errno : -EIO);
		goto out;
	}

	/* create the items for the extent tree */
	memset(buf->data+sizeof(struct btrfs_header), 0,
		leafsize-sizeof(struct btrfs_header));
	nritems = 0;
	itemoff = __BTRFS_LEAF_DATA_SIZE(leafsize);
	for (i = 1; i < 7; i++) {
		item_size = sizeof(struct btrfs_extent_item);
		if (!skinny_metadata)
			item_size += sizeof(struct btrfs_tree_block_info);

		BUG_ON(blocks[i] < first_free);
		BUG_ON(blocks[i] < blocks[i - 1]);

		/* create extent item */
		itemoff -= item_size;
		btrfs_set_disk_key_objectid(&disk_key, blocks[i]);
		if (skinny_metadata) {
			btrfs_set_disk_key_type(&disk_key,
						BTRFS_METADATA_ITEM_KEY);
			btrfs_set_disk_key_offset(&disk_key, 0);
		} else {
			btrfs_set_disk_key_type(&disk_key,
						BTRFS_EXTENT_ITEM_KEY);
			btrfs_set_disk_key_offset(&disk_key, leafsize);
		}
		btrfs_set_item_key(buf, &disk_key, nritems);
		btrfs_set_item_offset(buf, btrfs_item_nr(nritems),
				      itemoff);
		btrfs_set_item_size(buf, btrfs_item_nr(nritems),
				    item_size);
		extent_item = btrfs_item_ptr(buf, nritems,
					     struct btrfs_extent_item);
		btrfs_set_extent_refs(buf, extent_item, 1);
		btrfs_set_extent_generation(buf, extent_item, 1);
		btrfs_set_extent_flags(buf, extent_item,
				       BTRFS_EXTENT_FLAG_TREE_BLOCK);
		nritems++;

		/* create extent ref */
		ref_root = reference_root_table[i];
		btrfs_set_disk_key_objectid(&disk_key, blocks[i]);
		btrfs_set_disk_key_offset(&disk_key, ref_root);
		btrfs_set_disk_key_type(&disk_key, BTRFS_TREE_BLOCK_REF_KEY);
		btrfs_set_item_key(buf, &disk_key, nritems);
		btrfs_set_item_offset(buf, btrfs_item_nr(nritems),
				      itemoff);
		btrfs_set_item_size(buf, btrfs_item_nr(nritems), 0);
		nritems++;
	}
	btrfs_set_header_bytenr(buf, blocks[2]);
	btrfs_set_header_owner(buf, BTRFS_EXTENT_TREE_OBJECTID);
	btrfs_set_header_nritems(buf, nritems);
	csum_tree_block_size(buf, BTRFS_CRC32_SIZE, 0);
	ret = pwrite(fd, buf->data, leafsize, blocks[2]);
	if (ret != leafsize) {
		ret = (ret < 0 ? -errno : -EIO);
		goto out;
	}

	/* create the chunk tree */
	memset(buf->data+sizeof(struct btrfs_header), 0,
		leafsize-sizeof(struct btrfs_header));
	nritems = 0;
	item_size = sizeof(*dev_item);
	itemoff = __BTRFS_LEAF_DATA_SIZE(leafsize) - item_size;

	/* first device 1 (there is no device 0) */
	btrfs_set_disk_key_objectid(&disk_key, BTRFS_DEV_ITEMS_OBJECTID);
	btrfs_set_disk_key_offset(&disk_key, 1);
	btrfs_set_disk_key_type(&disk_key, BTRFS_DEV_ITEM_KEY);
	btrfs_set_item_key(buf, &disk_key, nritems);
	btrfs_set_item_offset(buf, btrfs_item_nr(nritems), itemoff);
	btrfs_set_item_size(buf, btrfs_item_nr(nritems), item_size);

	dev_item = btrfs_item_ptr(buf, nritems, struct btrfs_dev_item);
	btrfs_set_device_id(buf, dev_item, 1);
	btrfs_set_device_generation(buf, dev_item, 0);
	btrfs_set_device_total_bytes(buf, dev_item, num_bytes);
	btrfs_set_device_bytes_used(buf, dev_item,
				    BTRFS_MKFS_SYSTEM_GROUP_SIZE);
	btrfs_set_device_io_align(buf, dev_item, sectorsize);
	btrfs_set_device_io_width(buf, dev_item, sectorsize);
	btrfs_set_device_sector_size(buf, dev_item, sectorsize);
	btrfs_set_device_type(buf, dev_item, 0);

	write_extent_buffer(buf, super.dev_item.uuid,
			    (unsigned long)btrfs_device_uuid(dev_item),
			    BTRFS_UUID_SIZE);
	write_extent_buffer(buf, super.fsid,
			    (unsigned long)btrfs_device_fsid(dev_item),
			    BTRFS_UUID_SIZE);
	read_extent_buffer(buf, &super.dev_item, (unsigned long)dev_item,
			   sizeof(*dev_item));

	nritems++;
	item_size = btrfs_chunk_item_size(1);
	itemoff = itemoff - item_size;

	/* then we have chunk 0 */
	btrfs_set_disk_key_objectid(&disk_key, BTRFS_FIRST_CHUNK_TREE_OBJECTID);
	btrfs_set_disk_key_offset(&disk_key, 0);
	btrfs_set_disk_key_type(&disk_key, BTRFS_CHUNK_ITEM_KEY);
	btrfs_set_item_key(buf, &disk_key, nritems);
	btrfs_set_item_offset(buf, btrfs_item_nr(nritems), itemoff);
	btrfs_set_item_size(buf, btrfs_item_nr(nritems), item_size);

	chunk = btrfs_item_ptr(buf, nritems, struct btrfs_chunk);
	btrfs_set_chunk_length(buf, chunk, BTRFS_MKFS_SYSTEM_GROUP_SIZE);
	btrfs_set_chunk_owner(buf, chunk, BTRFS_EXTENT_TREE_OBJECTID);
	btrfs_set_chunk_stripe_len(buf, chunk, 64 * 1024);
	btrfs_set_chunk_type(buf, chunk, BTRFS_BLOCK_GROUP_SYSTEM);
	btrfs_set_chunk_io_align(buf, chunk, sectorsize);
	btrfs_set_chunk_io_width(buf, chunk, sectorsize);
	btrfs_set_chunk_sector_size(buf, chunk, sectorsize);
	btrfs_set_chunk_num_stripes(buf, chunk, 1);
	btrfs_set_stripe_devid_nr(buf, chunk, 0, 1);
	btrfs_set_stripe_offset_nr(buf, chunk, 0, 0);
	nritems++;

	write_extent_buffer(buf, super.dev_item.uuid,
			    (unsigned long)btrfs_stripe_dev_uuid(&chunk->stripe),
			    BTRFS_UUID_SIZE);

	/* copy the key for the chunk to the system array */
	ptr = super.sys_chunk_array;
	array_size = sizeof(disk_key);

	memcpy(ptr, &disk_key, sizeof(disk_key));
	ptr += sizeof(disk_key);

	/* copy the chunk to the system array */
	read_extent_buffer(buf, ptr, (unsigned long)chunk, item_size);
	array_size += item_size;
	ptr += item_size;
	btrfs_set_super_sys_array_size(&super, array_size);

	btrfs_set_header_bytenr(buf, blocks[3]);
	btrfs_set_header_owner(buf, BTRFS_CHUNK_TREE_OBJECTID);
	btrfs_set_header_nritems(buf, nritems);
	csum_tree_block_size(buf, BTRFS_CRC32_SIZE, 0);
	ret = pwrite(fd, buf->data, leafsize, blocks[3]);
	if (ret != leafsize) {
		ret = (ret < 0 ? -errno : -EIO);
		goto out;
	}

	/* create the device tree */
	memset(buf->data+sizeof(struct btrfs_header), 0,
		leafsize-sizeof(struct btrfs_header));
	nritems = 0;
	itemoff = __BTRFS_LEAF_DATA_SIZE(leafsize) -
		sizeof(struct btrfs_dev_extent);

	btrfs_set_disk_key_objectid(&disk_key, 1);
	btrfs_set_disk_key_offset(&disk_key, 0);
	btrfs_set_disk_key_type(&disk_key, BTRFS_DEV_EXTENT_KEY);
	btrfs_set_item_key(buf, &disk_key, nritems);
	btrfs_set_item_offset(buf, btrfs_item_nr(nritems), itemoff);
	btrfs_set_item_size(buf, btrfs_item_nr(nritems),
			    sizeof(struct btrfs_dev_extent));
	dev_extent = btrfs_item_ptr(buf, nritems, struct btrfs_dev_extent);
	btrfs_set_dev_extent_chunk_tree(buf, dev_extent,
					BTRFS_CHUNK_TREE_OBJECTID);
	btrfs_set_dev_extent_chunk_objectid(buf, dev_extent,
					BTRFS_FIRST_CHUNK_TREE_OBJECTID);
	btrfs_set_dev_extent_chunk_offset(buf, dev_extent, 0);

	write_extent_buffer(buf, chunk_tree_uuid,
		    (unsigned long)btrfs_dev_extent_chunk_tree_uuid(dev_extent),
		    BTRFS_UUID_SIZE);

	btrfs_set_dev_extent_length(buf, dev_extent,
				    BTRFS_MKFS_SYSTEM_GROUP_SIZE);
	nritems++;

	btrfs_set_header_bytenr(buf, blocks[4]);
	btrfs_set_header_owner(buf, BTRFS_DEV_TREE_OBJECTID);
	btrfs_set_header_nritems(buf, nritems);
	csum_tree_block_size(buf, BTRFS_CRC32_SIZE, 0);
	ret = pwrite(fd, buf->data, leafsize, blocks[4]);
	if (ret != leafsize) {
		ret = (ret < 0 ? -errno : -EIO);
		goto out;
	}

	/* create the FS root */
	memset(buf->data+sizeof(struct btrfs_header), 0,
		leafsize-sizeof(struct btrfs_header));
	btrfs_set_header_bytenr(buf, blocks[5]);
	btrfs_set_header_owner(buf, BTRFS_FS_TREE_OBJECTID);
	btrfs_set_header_nritems(buf, 0);
	csum_tree_block_size(buf, BTRFS_CRC32_SIZE, 0);
	ret = pwrite(fd, buf->data, leafsize, blocks[5]);
	if (ret != leafsize) {
		ret = (ret < 0 ? -errno : -EIO);
		goto out;
	}
	/* finally create the csum root */
	memset(buf->data+sizeof(struct btrfs_header), 0,
		leafsize-sizeof(struct btrfs_header));
	btrfs_set_header_bytenr(buf, blocks[6]);
	btrfs_set_header_owner(buf, BTRFS_CSUM_TREE_OBJECTID);
	btrfs_set_header_nritems(buf, 0);
	csum_tree_block_size(buf, BTRFS_CRC32_SIZE, 0);
	ret = pwrite(fd, buf->data, leafsize, blocks[6]);
	if (ret != leafsize) {
		ret = (ret < 0 ? -errno : -EIO);
		goto out;
	}

	/* and write out the super block */
	BUG_ON(sizeof(super) > sectorsize);
	memset(buf->data, 0, sectorsize);
	memcpy(buf->data, &super, sizeof(super));
	buf->len = sectorsize;
	csum_tree_block_size(buf, BTRFS_CRC32_SIZE, 0);
	ret = pwrite(fd, buf->data, sectorsize, blocks[0]);
	if (ret != sectorsize) {
		ret = (ret < 0 ? -errno : -EIO);
		goto out;
	}

	ret = 0;

out:
	free(buf);
	return ret;
}
Пример #3
0
/*
 * at transaction commit time we need to schedule the old roots for
 * deletion via btrfs_drop_snapshot.  This runs through all the
 * reference counted roots that were modified in the current
 * transaction and puts them into the drop list
 */
static noinline int add_dirty_roots(struct btrfs_trans_handle *trans,
                                    struct radix_tree_root *radix,
                                    struct list_head *list)
{
    struct btrfs_dirty_root *dirty;
    struct btrfs_root *gang[8];
    struct btrfs_root *root;
    int i;
    int ret;
    int err = 0;
    u32 refs;

    while (1) {
        ret = radix_tree_gang_lookup_tag(radix, (void **)gang, 0,
                                         ARRAY_SIZE(gang),
                                         BTRFS_ROOT_TRANS_TAG);
        if (ret == 0)
            break;
        for (i = 0; i < ret; i++) {
            root = gang[i];
            radix_tree_tag_clear(radix,
                                 (unsigned long)root->root_key.objectid,
                                 BTRFS_ROOT_TRANS_TAG);

            BUG_ON(!root->ref_tree);
            dirty = root->dirty_root;

            btrfs_free_log(trans, root);
            btrfs_free_reloc_root(trans, root);

            if (root->commit_root == root->node) {
                WARN_ON(root->node->start !=
                        btrfs_root_bytenr(&root->root_item));

                free_extent_buffer(root->commit_root);
                root->commit_root = NULL;
                root->dirty_root = NULL;

                spin_lock(&root->list_lock);
                list_del_init(&dirty->root->dead_list);
                spin_unlock(&root->list_lock);

                kfree(dirty->root);
                kfree(dirty);

                /* make sure to update the root on disk
                 * so we get any updates to the block used
                 * counts
                 */
                err = btrfs_update_root(trans,
                                        root->fs_info->tree_root,
                                        &root->root_key,
                                        &root->root_item);
                continue;
            }

            memset(&root->root_item.drop_progress, 0,
                   sizeof(struct btrfs_disk_key));
            root->root_item.drop_level = 0;
            root->commit_root = NULL;
            root->dirty_root = NULL;
            root->root_key.offset = root->fs_info->generation;
            btrfs_set_root_bytenr(&root->root_item,
                                  root->node->start);
            btrfs_set_root_level(&root->root_item,
                                 btrfs_header_level(root->node));
            btrfs_set_root_generation(&root->root_item,
                                      root->root_key.offset);

            err = btrfs_insert_root(trans, root->fs_info->tree_root,
                                    &root->root_key,
                                    &root->root_item);
            if (err)
                break;

            refs = btrfs_root_refs(&dirty->root->root_item);
            btrfs_set_root_refs(&dirty->root->root_item, refs - 1);
            err = btrfs_update_root(trans, root->fs_info->tree_root,
                                    &dirty->root->root_key,
                                    &dirty->root->root_item);

            BUG_ON(err);
            if (refs == 1) {
                list_add(&dirty->list, list);
            } else {
                WARN_ON(1);
                free_extent_buffer(dirty->root->node);
                kfree(dirty->root);
                kfree(dirty);
            }
        }
    }
    return err;
}