Koji supports using different storage volumes for builds, but the scratch directory is restricted to the default volume.

This change replaces os.rename and os.link calls with a call that handles moves across mounts gracefully. This allows admins to make the scratch directory a separate mount.

+1

Maybe re-do the syntax here to raise koji.GenericError("Destination exists: %s" % dst) just to prepare the way for a py3 port some day.

Using python-lockfile this is relatively straightforward with: with lockfile.FileLock(src)

Agreed. Looks sane in general.