Is it possible to make ext4 images reproducible even after filesystem operations ?

[David A. Wheeler]

> On Jan 9, 2025, at 12:22 AM, Adithya.Balakumar at toshiba-tsip.com wrote:
> 
> Hi All,
> 
> I am working towards reproducible builds for a project that I am involved in. We use a few ext4 partitions in our disk images and I am trying to make the ext4 filesystems reproducible.

I'm a little concerned with this as a goal, at least if your goal is to detect & counter builds that don't do what they claim to do.

Different versions of operating systems will generate different bit images for a given partition, and of course, not everyone uses ext4. If you must, I imagine you should userspace tools (over which you have complete control & can fix version numbers), then run them to make changes in a sequential order.

For most cases I can think of, they should be compared file-by-file and dir-by-dir, ignoring the filesystem. But your use case may be VERY different from what I have in mind.

--- David A. Wheeler