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

[Bernhard M. Wiedemann]

On 09/01/2025 06.22, Adithya.Balakumar at toshiba-tsip.com wrote:
> In the project that I am working on, there are some mount operations 
> done on the filesystem to copy certain files into the file system. This 
> updates the "Last mount" and "Last write" timestamps in the filesystem 
> metadata (confirmed this with dumpe2fs) thereby making the images 
> generated not reproducible.
> I would like to understand if its possible to make the ext4 images 
> reproducible even after filesystem operations like mounting and 
> unmounting the filesystem ?

In my
https://build.opensuse.org/projects/home:bmwiedemann:reproducible:distribution:ring1/packages/altimagebuild/files/mkimage.sh

I had the same issue with grub files that needed to be generated within 
the mounted block device. I solved it by copying out the modified files 
and running another
mkfs.ext2 -F -d $tar ...
to create an all new bit-reproducible VM image.

There are other ways such as libguestfs or
https://github.com/alperakcan/fuse-ext2 that could let you modify 
filesystem content the way you want. Could need some patches.

Ciao
Bernhard M.