fsnotify: Provide framework for dropping SRCU lock in ->handle_event

[sfrench/cifs-2.6.git] / include / linux / fsnotify_backend.h

diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h
index e6e689b5569e6f2abf00859874645620fadd3155..5bb6d988b9f6373afbdd4e0c72ad16d54dec0cf6 100644 (file)
--- a/include/linux/fsnotify_backend.h
+++ b/include/linux/fsnotify_backend.h
@@ -80,6 +80,7 @@ struct fsnotify_event;
 struct fsnotify_mark;
 struct fsnotify_event_private_data;
 struct fsnotify_fname;
+struct fsnotify_iter_info;
 
 /*
  * Each group much define these ops.  The fsnotify infrastructure will call
@@ -163,6 +164,8 @@ struct fsnotify_group {
        struct fsnotify_event *overflow_event;  /* Event we queue when the
                                                 * notification list is too
                                                 * full */
+       atomic_t user_waits;            /* Number of tasks waiting for user
+                                        * response */
 
        /* groups can define private fields here or use the void *private */
        union {
@@ -194,6 +197,28 @@ struct fsnotify_group {
 #define FSNOTIFY_EVENT_PATH    1
 #define FSNOTIFY_EVENT_INODE   2
 
+/*
+ * Inode / vfsmount point to this structure which tracks all marks attached to
+ * the inode / vfsmount. The reference to inode / vfsmount is held by this
+ * structure. We destroy this structure when there are no more marks attached
+ * to it. The structure is protected by fsnotify_mark_srcu.
+ */
+struct fsnotify_mark_connector {
+       spinlock_t lock;
+#define FSNOTIFY_OBJ_TYPE_INODE                0x01
+#define FSNOTIFY_OBJ_TYPE_VFSMOUNT     0x02
+       unsigned int flags;     /* Type of object [lock] */
+       union { /* Object pointer [lock] */
+               struct inode *inode;
+               struct vfsmount *mnt;
+       };
+       union {
+               struct hlist_head list;
+               /* Used listing heads to free after srcu period expires */
+               struct fsnotify_mark_connector *destroy_next;
+       };
+};
+
 /*
  * 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
@@ -223,20 +248,15 @@ struct fsnotify_mark {
        struct list_head g_list;
        /* Protects inode / mnt pointers, flags, masks */
        spinlock_t lock;
-       /* List of marks for inode / vfsmount [obj_lock] */
+       /* List of marks for inode / vfsmount [connector->lock, mark ref] */
        struct hlist_node obj_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 */
-       };
+       /* Head of list of marks for an object [mark ref] */
+       struct fsnotify_mark_connector *connector;
        /* 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
-#define FSNOTIFY_MARK_FLAG_ATTACHED            0x20
+#define FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY 0x01
+#define FSNOTIFY_MARK_FLAG_ALIVE               0x02
+#define FSNOTIFY_MARK_FLAG_ATTACHED            0x04
        unsigned int flags;             /* flags [mark->lock] */
        void (*free_mark)(struct fsnotify_mark *mark); /* called on final put+free */
 };
@@ -315,6 +335,8 @@ extern struct fsnotify_event *fsnotify_remove_first_event(struct fsnotify_group
 
 /* functions used to manipulate the marks attached to inodes */
 
+/* Calculate mask of events for a list of marks */
+extern void fsnotify_recalc_mask(struct fsnotify_mark_connector *conn);
 /* run all marks associated with a vfsmount and update mnt->mnt_fsnotify_mask */
 extern void fsnotify_recalc_vfsmount_mask(struct vfsmount *mnt);
 /* run all marks associated with an inode and update inode->i_fsnotify_mask */
@@ -344,11 +366,13 @@ extern void fsnotify_free_mark(struct fsnotify_mark *mark);
 extern void fsnotify_clear_vfsmount_marks_by_group(struct fsnotify_group *group);
 /* run all the marks in a group, and clear all of the inode marks */
 extern void fsnotify_clear_inode_marks_by_group(struct fsnotify_group *group);
-/* run all the marks in a group, and clear all of the marks where mark->flags & flags is true*/
+/* run all the marks in a group, and clear all of the marks attached to given object type */
 extern void fsnotify_clear_marks_by_group_flags(struct fsnotify_group *group, unsigned int flags);
 extern void fsnotify_get_mark(struct fsnotify_mark *mark);
 extern void fsnotify_put_mark(struct fsnotify_mark *mark);
 extern void fsnotify_unmount_inodes(struct super_block *sb);
+extern void fsnotify_finish_user_wait(struct fsnotify_iter_info *iter_info);
+extern bool fsnotify_prepare_user_wait(struct fsnotify_iter_info *iter_info);
 
 /* put here because inotify does some weird stuff when destroying watches */
 extern void fsnotify_init_event(struct fsnotify_event *event,