fanotify: store fanotify_init() flags in group's fanotify_data

This averts the need to re-generate flags in fanotify_show_fdinfo()
and sets the scene for addition of more upcoming flags without growing
new members to the fanotify_data struct.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>

include/linux/fanotify.h

@@ -6,4 +6,8 @@
 
 /* not valid from userspace, only kernel internal */
 #define FAN_MARK_ONDIR		0x00000100
+
+#define FAN_GROUP_FLAG(group, flag) \
+	((group)->fanotify_data.flags & (flag))
+
 #endif /* _LINUX_FANOTIFY_H */