[RFC] initoverlayfs - a scalable initial filesystem

[Eric Curtin]

Yes, your understanding is correct. I'm off at the moment, we will try and
open a PR sometime to explain it better.

By the way I'd also happily review your PR also if you think you could
explain it better.

At the moment it's a loopback mounted file from /boot, mounted as an erofs
with transient overlay on top, there's a corresponding initoverlayfs file
for each initramfs file basically.

But it could be configurable in future to load a raw erofs partition if
somebody wanted to do that.

Gonna try and do some of the storage-init things as systemd service scripts
soon.


On Mon, 18 Dec 2023, 22:00 Askar Safin, <safinaskar at gmail.com> wrote:

> Hi. Unfortunately, this is not clear enough from
> https://github.com/containers/initoverlayfs how exactly the
> second-stage early filesystem is mounted. So, please, add that
> information to README. Let me describe how I understand this.
>
> First, init program from (small) first-stage early filesystem mounts
> boot/ESP partition, where second-stage early filesystem image (i. e.
> erofs) is located. Then that init program mounts that erofs image.
> Without copying the whole erofs image into memory. In other words, if
> some part of erofs image is not accessed, then not only it is not
> uncompressed, it even is not loaded from disk to memory at all. Is my
> understanding correct?
>
> --
> Askar Safin
>
>
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