Bug#1031325: e2fsprogs 1.47.0 introduces a breaking change into Bookworm, breaking grub and making installations of Ubuntu and Debian releases via debootstrap impossible
On Thu, Feb 16, 2023 at 03:05:06PM -0800, Russ Allbery wrote:
>...
> Each time you change the defaults in a way that could be
> backward-incompatible, you could capture those new defaults in a
> permanently-fixed label of, say, 20230616, which is the defaults on that
> date. Probably in the default /etc/mke2fs.conf. I don't expect you to
> care about what systems they work with, what distributions they work with,
> or anything else other than the timeline of when you decided to change the
> defaults, something you're presumably already doing as a maintainer. The
> only additional work would be to update these labels with the settings
> required to make mke2fs with its current defaults behave compatibly with
> whatever the defaults had been at each of those captured points in time.
>
> (And obviously eventually you could drop the really old ones if it made no
> sense to keep supporting them, or have some single really-ancient fallback
> for really old systems, etc.)
>
> Then, image creators can look in /etc/mke2fs.conf for the timestamp that
> most closely aligns with the target system they want to create and use
> that group of settings. If that turns out to be inadequate, they can go
> back to a previous date.
The image creators could just set the features they enable to what they
copied from /etc/mke2fs.conf from the target distribution, a label with
a timestamp wouldn'tbring much benefit here.
We are talking about tools for creating filesystems and their authors,
users of these tools don't have to know anything about all that.
> Some work on their part is still required, but
> from their perspective I think this would have the advantage of not having
> to do research to reconstruct what all the options could be and how they
> changed and which ones were potentially backward-incompatible, which are
> all things you would generally already know and have in mind when you
> changed the defaults and thus could capture for them.
>...
Image creators usually support several different filesystems.
There is also the point that a tool in bookworm that supports creating
bullseye images will also support creating bookworm images, so when
there is a difference in the settings for bullseye and bookworm images
it should anyway be updated for the difference. Setting a new default
for bookworm or disabling a new feature for <= bullseye, the work is
trivial in any case and the hard part is all image creators being aware
that there is a difference.
cu
Adrian
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