atomic_t refcnt; /* nr of attached wb's and blkg */
#ifdef CONFIG_CGROUP_WRITEBACK
- struct backing_dev_info *bdi; /* the associated bdi */
+ struct backing_dev_info *__bdi; /* the associated bdi, set to NULL
+ * on bdi unregistration. For memcg-wb
+ * internal use only! */
int blkcg_id; /* ID of the associated blkcg */
struct rb_node rb_node; /* on bdi->cgwb_congestion_tree */
#endif