fsnotify: check to make sure all fsnotify bits are unique

This patch adds a check to make sure that all fsnotify bits are unique and we
cannot accidentally use the same bit for 2 different fsnotify event types.

Signed-off-by: Eric Paris <eparis@redhat.com>

2 files changed, 11 insertions, 0 deletions

diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c
index 9810babb1a3..076c10e959d 100644
--- a/fs/notify/fsnotify.c
+++ b/fs/notify/fsnotify.c
@@ -275,6 +275,8 @@ EXPORT_SYMBOL_GPL(fsnotify);
 
 static __init int fsnotify_init(void)
 {
+        BUG_ON(hweight32(ALL_FSNOTIFY_EVENTS) != 23);
+
         return init_srcu_struct(&fsnotify_grp_srcu);
 }
 subsys_initcall(fsnotify_init);
diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h
index 4b809fcd499..a46355db1e4 100644
--- a/include/linux/fsnotify_backend.h
+++ b/include/linux/fsnotify_backend.h
@@ -64,6 +64,15 @@
 
 #define FS_MOVE                 (FS_MOVED_FROM | FS_MOVED_TO)
 
+#define ALL_FSNOTIFY_EVENTS (FS_ACCESS | FS_MODIFY | FS_ATTRIB | \
+                             FS_CLOSE_WRITE | FS_CLOSE_NOWRITE | FS_OPEN | \
+                             FS_MOVED_FROM | FS_MOVED_TO | FS_CREATE | \
+                             FS_DELETE | FS_DELETE_SELF | FS_MOVE_SELF | \
+                             FS_UNMOUNT | FS_Q_OVERFLOW | FS_IN_IGNORED | \
+                             FS_OPEN_PERM | FS_ACCESS_PERM | FS_EXCL_UNLINK | \
+                             FS_IN_ISDIR | FS_IN_ONESHOT | FS_DN_RENAME | \
+                             FS_DN_MULTISHOT | FS_EVENT_ON_CHILD)
+
 struct fsnotify_group;
 struct fsnotify_event;
 struct fsnotify_mark;