+ /*
+ * Note that a running device replace operation is not
+ * canceled here although there is no way to update
+ * the progress. It would add the risk of a deadlock,
+ * therefore the canceling is ommited. The only penalty
+ * is that some I/O remains active until the procedure
+ * completes. The next time when the filesystem is
+ * mounted writeable again, the device replace
+ * operation continues.
+ */