fsnotify: remove group->mask

[net-next-2.6.git] / fs / notify / group.c

diff --git a/fs/notify/group.c b/fs/notify/group.c
index 34fccbd2809cec35f3c6a7a062c4e38ddb3f4385..fc0d966b270f74401047178050b1e27b8616bbeb 100644 (file)
--- a/fs/notify/group.c
+++ b/fs/notify/group.c
@@ -30,59 +30,60 @@
 
 /* protects writes to fsnotify_groups and fsnotify_mask */
 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 */
+/* all groups registered to receive inode filesystem notifications */
 LIST_HEAD(fsnotify_inode_groups);
-/* bitwise OR of all events (FS_*) interesting to some group on this system */
-__u32 fsnotify_inode_mask;
+/* all groups registered to receive mount point filesystem notifications */
+LIST_HEAD(fsnotify_vfsmount_groups);
 
-/*
- * When a new group registers or changes it's set of interesting events
- * this function updates the fsnotify_mask to contain all interesting events
- */
-void fsnotify_recalc_global_mask(void)
-{
-       struct fsnotify_group *group;
-       __u32 mask = 0;
-       int idx;
-
-       idx = srcu_read_lock(&fsnotify_grp_srcu);
-       list_for_each_entry_rcu(group, &fsnotify_inode_groups, inode_group_list)
-               mask |= group->mask;
-       srcu_read_unlock(&fsnotify_grp_srcu, idx);
-       fsnotify_inode_mask = mask;
-}
-
-/*
- * Update the group->mask by running all of the marks associated with this
- * group and finding the bitwise | of all of the mark->mask.  If we change
- * the group->mask we need to update the global mask of events interesting
- * to the system.
- */
-void fsnotify_recalc_group_mask(struct fsnotify_group *group)
+void fsnotify_add_vfsmount_group(struct fsnotify_group *group)
 {
-       __u32 mask = 0;
-       __u32 old_mask = group->mask;
-       struct fsnotify_mark_entry *entry;
+       struct fsnotify_group *group_iter;
 
-       spin_lock(&group->mark_lock);
-       list_for_each_entry(entry, &group->mark_entries, g_list)
-               mask |= entry->mask;
-       spin_unlock(&group->mark_lock);
+       mutex_lock(&fsnotify_grp_mutex);
 
-       group->mask = mask;
+       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 (group < group_iter) {
+                               /* 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;
 
-       if (old_mask != mask)
-               fsnotify_recalc_global_mask();
+       mutex_unlock(&fsnotify_grp_mutex);
 }
 
 void fsnotify_add_inode_group(struct fsnotify_group *group)
 {
+       struct fsnotify_group *group_iter;
+
        mutex_lock(&fsnotify_grp_mutex);
 
-       if (!group->on_inode_group_list)
+       /* add to global group list */
+       if (!group->on_inode_group_list) {
+               list_for_each_entry(group_iter, &fsnotify_inode_groups,
+                                   inode_group_list) {
+                       if (group < group_iter) {
+                               /* 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);
@@ -112,9 +113,11 @@ 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);
 
+       synchronize_srcu(&fsnotify_mark_srcu);
+
        /* past the point of no return, matches the initial value of 1 */
        if (atomic_dec_and_test(&group->num_marks))
                fsnotify_final_destroy_group(group);
@@ -132,6 +135,9 @@ static void __fsnotify_evict_group(struct fsnotify_group *group)
        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;
 }
 
 /*
@@ -160,15 +166,8 @@ void fsnotify_put_group(struct fsnotify_group *group)
         */
        __fsnotify_evict_group(group);
 
-       /*
-        * now it's off the list, so the only thing we might care about is
-        * srcu access....
-        */
        mutex_unlock(&fsnotify_grp_mutex);
-       synchronize_srcu(&fsnotify_grp_srcu);
 
-       /* and now it is really dead. _Nothing_ could be seeing it */
-       fsnotify_recalc_global_mask();
        fsnotify_destroy_group(group);
 }
 
@@ -197,9 +196,10 @@ struct fsnotify_group *fsnotify_alloc_group(const struct fsnotify_ops *ops)
        group->max_events = UINT_MAX;
 
        INIT_LIST_HEAD(&group->inode_group_list);
+       INIT_LIST_HEAD(&group->vfsmount_group_list);
 
        spin_lock_init(&group->mark_lock);
-       INIT_LIST_HEAD(&group->mark_entries);
+       INIT_LIST_HEAD(&group->marks_list);
 
        group->ops = ops;