which fixes the bad commit 18473467d55a20d643b6c9b3a52de42f705b4d35
that was tracked down via bisecting, and has a Cc for qemu-stable as
well.
Issue was easy enough to reproduce with a single virtio-block disk
using a few runs of dd if=/dev/urandom of=file bs=1M count=1000
Commit cc071629539dc1f303175a7e2d4ab854c0a8b20f upstream.
Signed-off-by: Fabian Ebner <f.ebner@proxmox.com>