1 files changed, 96 insertions, 82 deletions

diff --git a/fs/notify/group.c b/fs/notify/group.c
index 0e1677144bc5..ada913fd4f7f 100644
--- a/fs/notify/group.c
+++ b/fs/notify/group.c
@@ -32,10 +32,14 @@
 static DEFINE_MUTEX(fsnotify_grp_mutex);
 /* protects reads while running the fsnotify_groups list */
 struct srcu_struct fsnotify_grp_srcu;
-/* all groups registered to receive filesystem notifications */
-LIST_HEAD(fsnotify_groups);
+/* all groups registered to receive inode filesystem notifications */
+LIST_HEAD(fsnotify_inode_groups);
+/* all groups registered to receive mount point filesystem notifications */
+LIST_HEAD(fsnotify_vfsmount_groups);
 /* bitwise OR of all events (FS_*) interesting to some group on this system */
-__u32 fsnotify_mask;
+__u32 fsnotify_inode_mask;
+/* bitwise OR of all events (FS_*) interesting to some group on this system */
+__u32 fsnotify_vfsmount_mask;
 
 /*
  * When a new group registers or changes it's set of interesting events
@@ -44,14 +48,20 @@ __u32 fsnotify_mask;
 void fsnotify_recalc_global_mask(void)
 {
 	struct fsnotify_group *group;
-	__u32 mask = 0;
+	__u32 inode_mask = 0;
+	__u32 vfsmount_mask = 0;
 	int idx;
 
 	idx = srcu_read_lock(&fsnotify_grp_srcu);
-	list_for_each_entry_rcu(group, &fsnotify_groups, group_list)
-		mask |= group->mask;
+	list_for_each_entry_rcu(group, &fsnotify_inode_groups, inode_group_list)
+		inode_mask |= group->mask;
+	list_for_each_entry_rcu(group, &fsnotify_vfsmount_groups, vfsmount_group_list)
+		vfsmount_mask |= group->mask;
+		
 	srcu_read_unlock(&fsnotify_grp_srcu, idx);
-	fsnotify_mask = mask;
+
+	fsnotify_inode_mask = inode_mask;
+	fsnotify_vfsmount_mask = vfsmount_mask;
 }
 
 /*
@@ -64,11 +74,11 @@ void fsnotify_recalc_group_mask(struct fsnotify_group *group)
 {
 	__u32 mask = 0;
 	__u32 old_mask = group->mask;
-	struct fsnotify_mark_entry *entry;
+	struct fsnotify_mark *mark;
 
 	spin_lock(&group->mark_lock);
-	list_for_each_entry(entry, &group->mark_entries, g_list)
-		mask |= entry->mask;
+	list_for_each_entry(mark, &group->marks_list, g_list)
+		mask |= mark->mask;
 	spin_unlock(&group->mark_lock);
 
 	group->mask = mask;
@@ -77,13 +87,60 @@ void fsnotify_recalc_group_mask(struct fsnotify_group *group)
 		fsnotify_recalc_global_mask();
 }
 
-/*
- * Take a reference to a group so things found under the fsnotify_grp_mutex
- * can't get freed under us
- */
-static void fsnotify_get_group(struct fsnotify_group *group)
+void fsnotify_add_vfsmount_group(struct fsnotify_group *group)
 {
-	atomic_inc(&group->refcnt);
+	struct fsnotify_group *group_iter;
+	unsigned int priority = group->priority;
+
+	mutex_lock(&fsnotify_grp_mutex);
+
+	if (!group->on_vfsmount_group_list) {
+		list_for_each_entry(group_iter, &fsnotify_vfsmount_groups,
+				    vfsmount_group_list) {
+			/* insert in front of this one? */
+			if (priority < group_iter->priority) {
+				/* list_add_tail() insert in front of group_iter */
+				list_add_tail_rcu(&group->inode_group_list,
+						  &group_iter->inode_group_list);
+				goto out;
+			}
+		}
+
+		/* apparently we need to be the last entry */
+		list_add_tail_rcu(&group->vfsmount_group_list, &fsnotify_vfsmount_groups);
+	}
+out:
+	group->on_vfsmount_group_list = 1;
+
+	mutex_unlock(&fsnotify_grp_mutex);
+}
+
+void fsnotify_add_inode_group(struct fsnotify_group *group)
+{
+	struct fsnotify_group *group_iter;
+	unsigned int priority = group->priority;
+
+	mutex_lock(&fsnotify_grp_mutex);
+
+	/* add to global group list, priority 0 first, UINT_MAX last */
+	if (!group->on_inode_group_list) {
+		list_for_each_entry(group_iter, &fsnotify_inode_groups,
+				    inode_group_list) {
+			if (priority < group_iter->priority) {
+				/* list_add_tail() insert in front of group_iter */
+				list_add_tail_rcu(&group->inode_group_list,
+						  &group_iter->inode_group_list);
+				goto out;
+			}
+		}
+
+		/* apparently we need to be the last entry */
+		list_add_tail_rcu(&group->inode_group_list, &fsnotify_inode_groups);
+	}
+out:
+	group->on_inode_group_list = 1;
+
+	mutex_unlock(&fsnotify_grp_mutex);
 }
 
 /*
@@ -110,7 +167,7 @@ void fsnotify_final_destroy_group(struct fsnotify_group *group)
  */
 static void fsnotify_destroy_group(struct fsnotify_group *group)
 {
-	/* clear all inode mark entries for this group */
+	/* clear all inode marks for this group */
 	fsnotify_clear_marks_by_group(group);
 
 	/* past the point of no return, matches the initial value of 1 */
@@ -127,9 +184,12 @@ static void __fsnotify_evict_group(struct fsnotify_group *group)
 {
 	BUG_ON(!mutex_is_locked(&fsnotify_grp_mutex));
 
-	if (group->on_group_list)
-		list_del_rcu(&group->group_list);
-	group->on_group_list = 0;
+	if (group->on_inode_group_list)
+		list_del_rcu(&group->inode_group_list);
+	group->on_inode_group_list = 0;
+	if (group->on_vfsmount_group_list)
+		list_del_rcu(&group->vfsmount_group_list);
+	group->on_vfsmount_group_list = 0;
 }
 
 /*
@@ -171,84 +231,38 @@ void fsnotify_put_group(struct fsnotify_group *group)
 }
 
 /*
- * Simply run the fsnotify_groups list and find a group which matches
- * the given parameters.  If a group is found we take a reference to that
- * group.
+ * Create a new fsnotify_group and hold a reference for the group returned.
  */
-static struct fsnotify_group *fsnotify_find_group(unsigned int group_num, __u32 mask,
-						  const struct fsnotify_ops *ops)
+struct fsnotify_group *fsnotify_alloc_group(const struct fsnotify_ops *ops)
 {
-	struct fsnotify_group *group_iter;
-	struct fsnotify_group *group = NULL;
-
-	BUG_ON(!mutex_is_locked(&fsnotify_grp_mutex));
-
-	list_for_each_entry_rcu(group_iter, &fsnotify_groups, group_list) {
-		if (group_iter->group_num == group_num) {
-			if ((group_iter->mask == mask) &&
-			    (group_iter->ops == ops)) {
-				fsnotify_get_group(group_iter);
-				group = group_iter;
-			} else
-				group = ERR_PTR(-EEXIST);
-		}
-	}
-	return group;
-}
-
-/*
- * Either finds an existing group which matches the group_num, mask, and ops or
- * creates a new group and adds it to the global group list.  In either case we
- * take a reference for the group returned.
- */
-struct fsnotify_group *fsnotify_obtain_group(unsigned int group_num, __u32 mask,
-					     const struct fsnotify_ops *ops)
-{
-	struct fsnotify_group *group, *tgroup;
+	struct fsnotify_group *group;
 
-	/* very low use, simpler locking if we just always alloc */
-	group = kmalloc(sizeof(struct fsnotify_group), GFP_KERNEL);
+	group = kzalloc(sizeof(struct fsnotify_group), GFP_KERNEL);
 	if (!group)
 		return ERR_PTR(-ENOMEM);
 
+	/* set to 0 when there a no external references to this group */
 	atomic_set(&group->refcnt, 1);
-
-	group->on_group_list = 0;
-	group->group_num = group_num;
-	group->mask = mask;
+	/*
+	 * hits 0 when there are no external references AND no marks for
+	 * this group
+	 */
+	atomic_set(&group->num_marks, 1);
 
 	mutex_init(&group->notification_mutex);
 	INIT_LIST_HEAD(&group->notification_list);
 	init_waitqueue_head(&group->notification_waitq);
-	group->q_len = 0;
 	group->max_events = UINT_MAX;
 
-	spin_lock_init(&group->mark_lock);
-	atomic_set(&group->num_marks, 0);
-	INIT_LIST_HEAD(&group->mark_entries);
+	INIT_LIST_HEAD(&group->inode_group_list);
+	INIT_LIST_HEAD(&group->vfsmount_group_list);
 
-	group->ops = ops;
-
-	mutex_lock(&fsnotify_grp_mutex);
-	tgroup = fsnotify_find_group(group_num, mask, ops);
-	if (tgroup) {
-		/* group already exists */
-		mutex_unlock(&fsnotify_grp_mutex);
-		/* destroy the new one we made */
-		fsnotify_put_group(group);
-		return tgroup;
-	}
-
-	/* group not found, add a new one */
-	list_add_rcu(&group->group_list, &fsnotify_groups);
-	group->on_group_list = 1;
-	/* being on the fsnotify_groups list holds one num_marks */
-	atomic_inc(&group->num_marks);
+	spin_lock_init(&group->mark_lock);
+	INIT_LIST_HEAD(&group->marks_list);
 
-	mutex_unlock(&fsnotify_grp_mutex);
+	group->priority = UINT_MAX;
 
-	if (mask)
-		fsnotify_recalc_global_mask();
+	group->ops = ops;
 
 	return group;
 }