diff options
| -rw-r--r-- | include/linux/fsnotify_backend.h | 50 |
1 files changed, 30 insertions, 20 deletions
diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h index 65a517dd32f7..dd6ddb0287ed 100644 --- a/include/linux/fsnotify_backend.h +++ b/include/linux/fsnotify_backend.h @@ -195,40 +195,50 @@ struct fsnotify_group { #define FSNOTIFY_EVENT_INODE 2 /* - * a mark is simply an object attached to an in core inode which allows an + * A mark is simply an object attached to an in core inode which allows an * fsnotify listener to indicate they are either no longer interested in events * of a type matching mask or only interested in those events. * - * these are flushed when an inode is evicted from core and may be flushed - * when the inode is modified (as seen by fsnotify_access). Some fsnotify users - * (such as dnotify) will flush these when the open fd is closed and not at - * inode eviction or modification. + * These are flushed when an inode is evicted from core and may be flushed + * when the inode is modified (as seen by fsnotify_access). Some fsnotify + * users (such as dnotify) will flush these when the open fd is closed and not + * at inode eviction or modification. + * + * Text in brackets is showing the lock(s) protecting modifications of a + * particular entry. obj_lock means either inode->i_lock or + * mnt->mnt_root->d_lock depending on the mark type. */ struct fsnotify_mark { - __u32 mask; /* mask this mark is for */ - /* we hold ref for each i_list and g_list. also one ref for each 'thing' + /* Mask this mark is for [mark->lock, group->mark_mutex] */ + __u32 mask; + /* We hold one for presence in g_list. Also one ref for each 'thing' * in kernel that found and may be using this mark. */ - atomic_t refcnt; /* active things looking at this mark */ - struct fsnotify_group *group; /* group this mark is for */ - struct list_head g_list; /* list of marks by group->i_fsnotify_marks - * Also reused for queueing mark into - * destroy_list when it's waiting for - * the end of SRCU period before it can - * be freed */ - spinlock_t lock; /* protect group and inode */ - struct hlist_node obj_list; /* list of marks for inode / vfsmount */ - struct list_head free_list; /* tmp list used when freeing this mark */ - union { + atomic_t refcnt; + /* Group this mark is for. Set on mark creation, stable until last ref + * is dropped */ + struct fsnotify_group *group; + /* List of marks by group->i_fsnotify_marks. Also reused for queueing + * mark into destroy_list when it's waiting for the end of SRCU period + * before it can be freed. [group->mark_mutex] */ + struct list_head g_list; + /* Protects inode / mnt pointers, flags, masks */ + spinlock_t lock; + /* List of marks for inode / vfsmount [obj_lock] */ + struct hlist_node obj_list; + /* tmp list used when freeing this mark */ + struct list_head free_list; + union { /* Object pointer [mark->lock, group->mark_mutex] */ struct inode *inode; /* inode this mark is associated with */ struct vfsmount *mnt; /* vfsmount this mark is associated with */ }; - __u32 ignored_mask; /* events types to ignore */ + /* Events types to ignore [mark->lock, group->mark_mutex] */ + __u32 ignored_mask; #define FSNOTIFY_MARK_FLAG_INODE 0x01 #define FSNOTIFY_MARK_FLAG_VFSMOUNT 0x02 #define FSNOTIFY_MARK_FLAG_OBJECT_PINNED 0x04 #define FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY 0x08 #define FSNOTIFY_MARK_FLAG_ALIVE 0x10 - unsigned int flags; /* vfsmount or inode mark? */ + unsigned int flags; /* flags [mark->lock] */ void (*free_mark)(struct fsnotify_mark *mark); /* called on final put+free */ }; |