brtfs_check.c

int btrfs_init_new_device(struct btrfs_fs_info *fs_info, const char *device_path)
{
	struct btrfs_root *root = fs_info->dev_root;
	struct btrfs_trans_handle *trans;
	struct btrfs_device *device;
	struct block_device *bdev;
	struct super_block *sb = fs_info->sb;
	struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
	struct btrfs_fs_devices *seed_devices;
	u64 orig_super_total_bytes;
	u64 orig_super_num_devices;
	int ret = 0;
	bool seeding_dev = false;
	bool locked = false;

	if (sb_rdonly(sb) && !fs_devices->seeding)
		return -EROFS;

	bdev = blkdev_get_by_path(device_path, FMODE_WRITE | FMODE_EXCL,
				  fs_info->bdev_holder);
	if (IS_ERR(bdev))
		return PTR_ERR(bdev);

	if (!btrfs_check_device_zone_type(fs_info, bdev)) {
		ret = -EINVAL;
		goto error;
	}

	if (fs_devices->seeding) {
		seeding_dev = true;
		down_write(&sb->s_umount);
		mutex_lock(&uuid_mutex);
		locked = true;
	}

	sync_blockdev(bdev);

	rcu_read_lock();
	list_for_each_entry_rcu(device, &fs_devices->devices, dev_list) {
		if (device->bdev == bdev) {
			ret = -EEXIST;
			rcu_read_unlock();
			goto error;
		}
	}
	rcu_read_unlock();

	device = btrfs_alloc_device(fs_info, NULL, NULL, device_path);
	if (IS_ERR(device)) {
		/* we can safely leave the fs_devices entry around */
		ret = PTR_ERR(device);
		goto error;
	}

	device->fs_info = fs_info;
	device->bdev = bdev;
	ret = lookup_bdev(device_path, &device->devt);
	if (ret)
		goto error_free_device;

	ret = btrfs_get_dev_zone_info(device, false);
	if (ret)
		goto error_free_device;

	trans = btrfs_start_transaction(root, 0);
	if (IS_ERR(trans)) {
		ret = PTR_ERR(trans);
		goto error_free_zone;
	}

	set_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state);
	device->generation = trans->transid;
	device->io_width = fs_info->sectorsize;
	device->io_align = fs_info->sectorsize;
	device->sector_size = fs_info->sectorsize;
	device->total_bytes =
		round_down(bdev_nr_bytes(bdev), fs_info->sectorsize);
	device->disk_total_bytes = device->total_bytes;
	device->commit_total_bytes = device->total_bytes;
	set_bit(BTRFS_DEV_STATE_IN_FS_METADATA, &device->dev_state);
	clear_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state);
	device->mode = FMODE_EXCL;
	device->dev_stats_valid = 1;
	set_blocksize(device->bdev, BTRFS_BDEV_BLOCKSIZE);

	if (seeding_dev) {
		btrfs_clear_sb_rdonly(sb);

		/* GFP_KERNEL allocation must not be under device_list_mutex */
		seed_devices = btrfs_init_sprout(fs_info);
		if (IS_ERR(seed_devices)) {
			ret = PTR_ERR(seed_devices);
			btrfs_abort_transaction(trans, ret);
			goto error_trans;
		}
	}

	mutex_lock(&fs_devices->device_list_mutex);
	if (seeding_dev) {
		btrfs_setup_sprout(fs_info, seed_devices);
		btrfs_assign_next_active_device(fs_info->fs_devices->latest_dev,
						device);
	}