fsnotify: intoduce a notification merge argument

Each group can define their own notification (and secondary_q) merge
function.  Inotify does tail drop, fanotify does matching and drop which
can actually allocate a completely new event.  But for fanotify to properly
deal with permissions events it needs to know the new event which was
ultimately added to the notification queue.  This patch just implements a
void ** argument which is passed to the merge function.  fanotify can use
this field to pass the new event back to higher layers.

Signed-off-by: Eric Paris <eparis@redhat.com>
for fanotify to properly deal with permissions events

1 files changed, 4 insertions, 2 deletions

diff --git a/fs/notify/inotify/inotify_fsnotify.c b/fs/notify/inotify/inotify_fsnotify.c
index 1d237e1bf7b1..daa666a6e6c9 100644
--- a/fs/notify/inotify/inotify_fsnotify.c
+++ b/fs/notify/inotify/inotify_fsnotify.c
@@ -67,7 +67,9 @@ static bool event_compare(struct fsnotify_event *old, struct fsnotify_event *new
         return false;
 }
 
-static int inotify_merge(struct list_head *list, struct fsnotify_event *event)
+static int inotify_merge(struct list_head *list,
+                         struct fsnotify_event *event,
+                         void **arg)
 {
         struct fsnotify_event_holder *last_holder;
         struct fsnotify_event *last_event;
@@ -114,7 +116,7 @@ static int inotify_handle_event(struct fsnotify_group *group, struct fsnotify_ev
         fsn_event_priv->group = group;
         event_priv->wd = wd;
 
-        ret = fsnotify_add_notify_event(group, event, fsn_event_priv, inotify_merge);
+        ret = fsnotify_add_notify_event(group, event, fsn_event_priv, inotify_merge, NULL);
         if (ret) {
                 inotify_free_event_priv(fsn_event_priv);
                 /* EEXIST says we tail matched, EOVERFLOW isn't something