fanotify: Add pids to events

Pass the process identifiers of the triggering processes to fanotify
listeners: this information is useful for event filtering and logging.

Signed-off-by: Andreas Gruenbacher <agruen@suse.de>
Signed-off-by: Eric Paris <eparis@redhat.com>
diff --git a/fs/notify/notification.c b/fs/notify/notification.c
index 066f1f9..7fc8d00 100644
--- a/fs/notify/notification.c
+++ b/fs/notify/notification.c
@@ -93,6 +93,7 @@
 		BUG_ON(!list_empty(&event->private_data_list));
 
 		kfree(event->file_name);
+		put_pid(event->tgid);
 		kmem_cache_free(fsnotify_event_cachep, event);
 	}
 }
@@ -346,6 +347,7 @@
 			return NULL;
 		}
 	}
+	event->tgid = get_pid(old_event->tgid);
 	if (event->data_type == FSNOTIFY_EVENT_PATH)
 		path_get(&event->path);
 
@@ -385,6 +387,7 @@
 		event->name_len = strlen(event->file_name);
 	}
 
+	event->tgid = get_pid(task_tgid(current));
 	event->sync_cookie = cookie;
 	event->to_tell = to_tell;
 	event->data_type = data_type;