- * XFS_I[O]LOCK_PARENT - for operations that require locking two inodes
- * (ie directory operations that require locking a directory inode and
- * an entry inode). The first inode gets locked with this flag so it
- * gets a lockdep subclass of 1 and the second lock will have a lockdep
- * subclass of 0.
+ * XFS_LOCK_PARENT - for directory operations that require locking a
+ * parent directory inode and a child entry inode. The parent gets locked
+ * with this flag so it gets a lockdep subclass of 1 and the child entry
+ * lock will have a lockdep subclass of 0.
+ *
+ * XFS_LOCK_RTBITMAP/XFS_LOCK_RTSUM - the realtime device bitmap and summary
+ * inodes do not participate in the normal lock order, and thus have their
+ * own subclasses.