Ah you actually do have an option for that, I was looking at some old docs probably.

" --fs-config-file=X    X=fs_config file\n"

Mate, I thank you sincerely, may the file system prosper.
Have a great weekend! 

On Fri, 20 Aug 2021 at 17:06, Gao Xiang <xiang@kernel.org> wrote:
On Fri, Aug 20, 2021 at 04:58:38PM +0300, Igor Eisberg wrote:
> Ah yes, silly me, got liblz4-1 confused with liblz4-dev, had to download
> the 1.9.3 *.deb packages manually cause apt-get is pushing 1.8.3.
> Now everything is working top-notch.
>
> Regarding mkfs.erofs, I know it can take file_contexts, but how should we
> handle fs_config, if it's even necessary?

I think you need mkfs.erofs from latest AOSP tree, we don't directly
enable fs_config for generic Linux build.

Thanks,
Gao Xiang