diff options
Diffstat (limited to 'include/linux/backing-dev-defs.h')
| -rw-r--r-- | include/linux/backing-dev-defs.h | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/include/linux/backing-dev-defs.h b/include/linux/backing-dev-defs.h index 9a6bc0951cfa..07e02d6df5ad 100644 --- a/include/linux/backing-dev-defs.h +++ b/include/linux/backing-dev-defs.h @@ -190,6 +190,7 @@ struct backing_dev_info { struct radix_tree_root cgwb_tree; /* radix tree of active cgroup wbs */ struct rb_root cgwb_congested_tree; /* their congested states */ struct mutex cgwb_release_mutex; /* protect shutdown of wb structs */ + struct rw_semaphore wb_switch_rwsem; /* no cgwb switch while syncing */ #else struct bdi_writeback_congested *wb_congested; #endif @@ -258,6 +259,14 @@ static inline void wb_get(struct bdi_writeback *wb) */ static inline void wb_put(struct bdi_writeback *wb) { + if (WARN_ON_ONCE(!wb->bdi)) { + /* + * A driver bug might cause a file to be removed before bdi was + * initialized. + */ + return; + } + if (wb != &wb->bdi->wb) percpu_ref_put(&wb->refcnt); } |