[Libguestfs] nbdkit Assertion `h->can_flush == 1' failed on Arch

https://aur.archlinux.org/packages/nbdkit/#comment-733981 reports that tests-parallel-nbd.sh hangs. Looking at the log file from the test reveals: nbdkit: backend.c:523: backend_flush: Assertion `h->can_flush == 1' failed. I've attached the full log. If you want to see other logs from the run (probably not relevant) then download https://svenne.dk/nbdkit-20200315/nbdkit-logs-20200315.tar.gz I believe the assertion comes from calling flush when can_flush previously returned false, but also I don't quite understand why the server is doing this. However I think the wider problem is that the reporter is using the non-libnbd "standalone" nbd plugin. I basically never test this any longer. I wonder if we should think about either having a way to routinely test it despite libnbd being installed, or simply dropping it? I will ask the reporter if they can try installing libnbd. Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming and virtualization blog: http://rwmj.wordpress.com virt-p2v converts physical machines to virtual machines. Boot with a live CD or over the network (PXE) and turn machines into KVM guests. http://libguestfs.org/virt-v2v