Re: [PATCH RFC 2/2] proto: read origin also for directories, chardevs and symlinks. copy timestamps from origin.

[Luca Di Maio <luca.dimaio1@gmail.com>]

Thanks Darrick for the review

> On 4/16/25 18:07, Darrick J. Wong wrote: The protofile format that
> mkfs.xfs uses has been static for 52 years, I don't know that
> expending a large amount of effort on it is worth the time.  If you
> really must have reproducible filesystem images, would it be easier
> to allow overriding current_time() via environment vars?

It's nice to preserve the source timestamps, for example, in case we
have also reproducible builds for packages and rootfs (in tar.gz format)
Fixing it to a set time would lose that information in the "translation"

> On 4/16/25 18:07, Darrick J. Wong wrote: (I also don't really get
> why anyone cares about bit-reproducible filesystem images; the only
> behavioral guarantees are the userspace interface contract.
> Filesystem drivers have wide latitude to do whatever they want under
> the covers.)

For distribution of said disks and avoiding re-doing work (eg: if the
checksum matches, we know there were no changes, thus we can skip the 
publication CI)

I've reviewed the patch, in order to not change the prototype file
specification whatsoever.
The new patch will leverage a comment that `xfs_protofile` inserts since
its first iteration:

": Descending path [foo]"

This way, if the comment is not found, like for older files, the new
behavior will simply be ignored.

This should address the compatibility concerns.
I've tested this incoming patch with a matrix of 
"old-protofiles/new-mkfs/new-protofile/old-mkfs" and it seems there are 
no compatibility issues.

Thanks
L.