RFC: erofs-utils:mkfs: add unprivileged container use-case support

[Naoto Yamaguchi]

Hi Gao

Thank you for your response.

> Could you give more details about this? EROFS already supports idmapped
> mount for container use cases since 5.19, so I guess uid/gid offsets
> can be set by this?

It's good news for me.  I  investigated LTS version 5.10 and 5.15.  I
didn’t know this new feature.

My work detail, it's easy to share experimental patch in my github.
https://github.com/AGLExport/erofs-utils/commit/d9080b80152c2f9065d98a7a2ac36912c74657ac

That will use combination with lxc idmap option.

ex:
Image creation
mkafs.erofs --uid-offset=100000 --gid-offset=100000 .....

Lxc config
lxc.idmap = u 0 100000 65536
lxc.idmap = g 0 100000 65536


Thanks,
Naoto Yamaguchi,
a member of Automotive Grade Linux Instrument Cluster EG.