I have made progress isolating the problem by using manual invocations of GNU tar.
Apparently the semantics of .tar .one-file-system. has changed. If I remove this option from my test invocation, the dump proceeds normally. -- To UNSUBSCRIBE, email to debian-bugs-rc-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org