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

[Gao Xiang]

On Wed, Aug 10, 2022 at 02:14:09AM +0800, Gao Xiang wrote:
> Hi Naoto,
> 
> On Wed, Aug 10, 2022 at 02:59:42AM +0900, Naoto Yamaguchi wrote:
> > Hi all.
> > 
> > I investigate each read only filesystem for linux at linux container
> > use-case.  The erofs is most interesting filesystem.
> 
> First of all, many thanks for your interest! Yes, now EROFS is actively
> developing for container use cases as well, and we're happy to
> accept/maintain any useful features about this area!
> 
> > A each files of guest root filesystem need to shift uid/gid in case of
> > unprivileged container to use uid/gid namespace.  I work adding
> > uid/gid offsetting support to erofs-utils mkfs tool now.
> > Will be this patch accept in upstream community?
> 
> 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?

Oh, I guess I've got this.  Yeah, I'm fine to introduce something like
uid or gid offsets as two long options if needed. ;)

Thanks,
Gao Xiang

> 
> I'm still somewhat new to container world, it would be helpful to drop
> more hints of this ;)
> 
> Thanks,
> Gao Xiang
> 
> > 
> > Thanks,
> > Naoto Yamaguchi,
> > a member of Automotive Grade Linux Instrument Cluster EG.