Re: [PATCH 37/37] ext5: define new subtype to add features and reduce testing complexity

Darrick J. Wong
2014-05-06T01:59:56Z

On Fri, May 02, 2014 at 10:04:07AM -0400, Theodore Ts'o wrote:
> On Fri, May 02, 2014 at 11:45:25AM +0200, Lukáš Czerner wrote:
> > This is definitely NACK by me. I do not like this and there are
> > several reasons why.
> >
> > First of all the name. Given the history of ext file system we tend
> > to increase then number with the new version of file system. However
> > you're saying that this is just for testing features ... in that
> > case it does not make any sense to call it ext5, but not just that
> > it's stupid to call it ext5 especially since we might actually want
> > to release ext5 in the future and this would be really confusing for
> > everybody involved.
>
> Yes, the messaging involved with the "ext3" vs "ext4" bump has been
> really unfortunate. If I had to do it all over again, I would have
> created "ext3dev", and then when it was stable, I would done a:
>
> git rm -rf fs/ext3 ; git mv fs/ext3dev fs/ext4
>
> For example, it would have avoided the problem with SuSE product
> managers refusing to support ext4 for multiple years, etc.
>
> It also would have avoided the problem with people doing comparisons
> of ext3 versus xfs, even in April 2014 (see a recent Hacker News
> promoted blog article, where in someone kvetched that ext3 didn't
> support fallocate). Sigh....

We could still do that, delete ext3 once we think "ext4 + new
features" is stable enough. It's not quite having only one extN
featureset in operation at a given time, but "a stable one" and "the
one we're working on" seems like plenty.

> > What about just simply using mkefs.conf to specify the feature set
> > we want and use that?
>
> Yes, it's likely that for 1.43 we'll enable various features by
> default. It's been quite deliberate that I haven't enabled by
> default, because I wanted to make 100% sure they were completely
> stable before enabling them by default. Some of them we may have been

Maybe I should have called this 'ext5alpha' or something, just to see
if I could generate wider interest in testing. I feel like these new
features are stable enough for some thorough testing, but they're a
pretty long way from 'completely stable'.

How widely are these features being tested? I'm rather dismayed that
I still find plenty of bugs to stick in the patchbomb. (Though I'm as
guilty as anyone else for contributing new features.)

> able to enable by default earlier, but be that as it may, 1.43 is a
> good time to make that change.

Hmm, I guess you were intending to update the mke2fs.conf definition of ext4,
then?

--D
>
> - Ted
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
--
To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html