Raboof

When I started debugging this issue, I had no idea how far down the rabbithole would go!

A few months ago, I was writing an end-to-end test for the Nextcloud integration with OnlyOffice under NixOS, to be run in a QEMU virtual machine. Curiously, my test suffered from corrupt reads from a host folder that was mounted into the VM. That was the start of a journey that led me deep into the Linux Kernel.

The circumstances under which the problem occured were very specific: a certain file,…