Re: [libvirt] [PATCH] util: storagefile: Properly set transport type when parsing NBD strings

On Thu, Jan 16, 2020 at 12:41:37PM +0100, Peter Krempa wrote: > When parsing legacy NBD backing file strings such as > 'nbd:unix:/tmp/sock:exportname=/' we'd fail to set the transport to > VIR_STORAGE_NET_HOST_TRANS_UNIX. This started to be a problem once we > actually started to generate config of the backing store on the command > line with -blockdev as the JSON code would try to format it as TCP and > fail with: > > internal error: argument key 'host' must not have null value > > Set the type properly and add a test. > > This bug was found by the libguestfs test suite in: > > https://bugzilla.redhat.com/show_bug.cgi?id=1791614 The bug was found by Ming Xie of the virt-v2v QE team. The patch itself looks fine as far as I can tell. But I'm having real problems actually testing it. Can you suggest any way to test libvirt parsing these URIs? My current method (which doesn't work for reasons that I don't understand) is: (1) Compile libvirt from source. (2) Run ./run src/libvirtd & (3) Create an NBD server + overlay file: rm /tmp/sock nbdkit -U /tmp/sock memory 1G qemu-img create -f qcow2 overlay.qcow2 -b nbd:unix:/tmp/sock:exportname=/ -F raw (4) Try to boot a libvirt guest using the overlay: virt-install --import --name test --disk path=overlay.qcow2,format=raw --memory 1024 But for some reason libvirt just ignores the overlay: 2020-01-16 13:00:44.980+0000: 2378711: warning : virStorageBackendVolOpen:1527 : ignoring missing file 'nbd:unix:/tmp/sock' I verified that the overlay works in programs like qemu-img so it doesn't seem to be a problem with the overlay itself.