A test case, attached. Note that you have to look at the output of the final qemu-img info command. In the case where it goes wrong, the 'backing file:' and 'backing file format:' lines disappear completely. In the case where the bug is not reproduced, these lines are still present.
It's 100% reproducible for me when lazy_refcounts=on, and 0% reproducible when lazy_refcounts=off. BUT it only occurs if the backing file is a remote source (nbd:... in this case), not if the backing file is a plain file. Make of that what you will. Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming and virtualization blog: http://rwmj.wordpress.com virt-top is 'top' for virtual machines. Tiny program with many powerful monitoring features, net stats, disk stats, logging, etc. http://people.redhat.com/~rjones/virt-top
qemu-lazy-refcounts.sh
Description: Bourne shell script
