inotify: force inotify and fsnotify use same bits

inotify uses bits called IN_* and fsnotify uses bits called FS_*.  These
need to line up.  This patch adds build time checks to make sure noone can
change these bits so they are not the same.
Signed-off-by: Eric Paris <eparis@redhat.com>

fs/notify/inotify/inotify_user.c

@@ -839,6 +839,27 @@ SYSCALL_DEFINE2(inotify_rm_watch, int, fd, __s32, wd)
  */
 static int __init inotify_user_setup(void)
 {
+	BUILD_BUG_ON(IN_ACCESS != FS_ACCESS);
+	BUILD_BUG_ON(IN_MODIFY != FS_MODIFY);
+	BUILD_BUG_ON(IN_ATTRIB != FS_ATTRIB);
+	BUILD_BUG_ON(IN_CLOSE_WRITE != FS_CLOSE_WRITE);
+	BUILD_BUG_ON(IN_CLOSE_NOWRITE != FS_CLOSE_NOWRITE);
+	BUILD_BUG_ON(IN_OPEN != FS_OPEN);
+	BUILD_BUG_ON(IN_MOVED_FROM != FS_MOVED_FROM);
+	BUILD_BUG_ON(IN_MOVED_TO != FS_MOVED_TO);
+	BUILD_BUG_ON(IN_CREATE != FS_CREATE);
+	BUILD_BUG_ON(IN_DELETE != FS_DELETE);
+	BUILD_BUG_ON(IN_DELETE_SELF != FS_DELETE_SELF);
+	BUILD_BUG_ON(IN_MOVE_SELF != FS_MOVE_SELF);
+	BUILD_BUG_ON(IN_UNMOUNT != FS_UNMOUNT);
+	BUILD_BUG_ON(IN_Q_OVERFLOW != FS_Q_OVERFLOW);
+	BUILD_BUG_ON(IN_IGNORED != FS_IN_IGNORED);
+	BUILD_BUG_ON(IN_EXCL_UNLINK != FS_EXCL_UNLINK);
+	BUILD_BUG_ON(IN_ISDIR != FS_IN_ISDIR);
+	BUILD_BUG_ON(IN_ONESHOT != FS_IN_ONESHOT);
+
+	BUG_ON(hweight32(ALL_INOTIFY_BITS) != 21);
+
 	inotify_inode_mark_cachep = KMEM_CACHE(inotify_inode_mark, SLAB_PANIC);
 	event_priv_cachep = KMEM_CACHE(inotify_event_private_data, SLAB_PANIC);
 

include/linux/inotify.h

@@ -73,6 +73,15 @@ struct inotify_event {
 #ifdef __KERNEL__
 #include <linux/sysctl.h>
 extern struct ctl_table inotify_table[]; /* for sysctl */
+
+#define ALL_INOTIFY_BITS (IN_ACCESS | IN_MODIFY | IN_ATTRIB | IN_CLOSE_WRITE | \
+			  IN_CLOSE_NOWRITE | IN_OPEN | IN_MOVED_FROM | \
+			  IN_MOVED_TO | IN_CREATE | IN_DELETE | \
+			  IN_DELETE_SELF | IN_MOVE_SELF | IN_UNMOUNT | \
+			  IN_Q_OVERFLOW | IN_IGNORED | IN_ONLYDIR | \
+			  IN_DONT_FOLLOW | IN_EXCL_UNLINK | IN_MASK_ADD | \
+			  IN_ISDIR | IN_ONESHOT)
+
 #endif
 
 #endif	/* _LINUX_INOTIFY_H */