submodule not installed via ansible-galaxy

[Fatsie]

I tried to install debops-contrib.btrfs through ansible-galaxy with:

 ansible-galaxy install debops-contrib.btrfs

When trying to use the role I get the following error:

ERROR! couldn't resolve module/action 'btrfs_subvolume'. This often indicates a misspelling, missing collection, or incorrect module path.

Problem seems to be that ansible-galaxy does not handle the ansible-btrfs-subvolume submodule. I solved it by recursively cloning this repo and copying submodules to ~/.ansible/roles/debops-contrib.btrfs