struct btrfs_caching_control *btrfs_get_caching_control(
		struct btrfs_block_group *cache)
{
	struct btrfs_caching_control *ctl;

	spin_lock(&cache->lock);
	if (!cache->caching_ctl) {
		spin_unlock(&cache->lock);
		return NULL;
	}

	ctl = cache->caching_ctl;
	refcount_inc(&ctl->count);
	spin_unlock(&cache->lock);
	return ctl;
}
struct btrfs_caching_control *btrfs_get_caching_control(
		struct btrfs_block_group *cache)
{
	struct btrfs_caching_control *ctl;

	spin_lock(&cache->lock);
	if (!cache->caching_ctl) {
		spin_unlock(&cache->lock);
		return NULL;
	}

	ctl = cache->caching_ctl;
	refcount_inc(&ctl->count);
	spin_unlock(&cache->lock);
	return ctl;
}