error: chmod not implemented with overlayfs

[Sohalt]

When trying to use a writeableStoreOverlay I get errors like: error: chmod '/nix/store/as1xzrm2921pnxx4jvxj39jn4v88wdy1-gcc-11.3.0': Function not implemented.

Any idea why that is happening?

[astro]

Store is a volume, not a share (which doesn't work), right? What filesystem is the volume?

[Sohalt]

Yes, store is a volume with ext4 (defaults).

[Sohalt]

The error shows up with cloud-hypervisor using virtiofsd to share the host store. Using a different hypervisor and 9p works.
The issue is probably due to https://lore.kernel.org/lkml/4B9D76D5-C794-4A49-A76F-3D4C10385EE0@kohlschutter.com/

[astro]

Thanks for doing the research!

To close this and #43 we have to document which hypervisor/virtiofs/9p combinations are usable for the store overlay.