Re: [PATCH 0/3] bcachefs support

Eryu Guan
2021-05-16T13:54:45Z

On Mon, May 10, 2021 at 06:26:45PM -0700, Darrick J. Wong wrote:
> On Tue, May 11, 2021 at 09:14:46AM +1000, Dave Chinner wrote:
> > On Sun, May 09, 2021 at 10:20:38PM +0800, Eryu Guan wrote:
> > > On Tue, Apr 27, 2021 at 12:44:16PM -0400, Kent Overstreet wrote:
> > > > A small patch adding bcachefs support, and two other patches for consideration:
> > >
> > > As bcachefs is not upstream yet, I think we should re-visit bcachefs
> > > support after it's in upstream.
> >
> > I disagree completely. I've been waiting for this to land for some
> > time so I can actually run fstests against bcachefs easily to
> > evaluate it's current state of stability and support. The plans are
> > to get bcachefs merged upstream, and so having support already in
> > fstests makes it much easier for reviewers and developers to
> > actually run tests and find problems prior to merging.
> >
> > As an upstream developer and someone who will be reviewing bcachefs
> > when it is next proposed for merge, I would much prefer to see
> > extensive and long term fstests coverage *before* the code is even
> > merged upstream. Given that filesystems take years to develop to the
> > point where they are stable and ready for merge, saying "can't
> > enable the test environment until it is merged upstream" is not very
> > helpful.
> >
> > As a general principle, we want developers of new filesystems to
> > start using fstests early in the development process of their
> > filesystem. We should be encouraging new filesystems to be added to
> > fstests, not saying "we only support upstream filesystems". If the
> > filesystem plans to be merged upstream, then fstests support for
> > that filesystem should be there long before the filesytsem is even
> > proposed for merge. We need to help people get new filesystems
> > upstream, not place arbitrary "not upstream so not supported"
> > catch-22s in their way...

OK, that makes sense. Actually, I should have made my "upstream first"
more clear. I'd love to merge non-upstream features/new fs supports if
the proposed new feature/new filesystem has been developmented actively
and the community has generally made the agreement that will merge the
new feature/filesystem when it's in a good shape. IOW, it's not some
random new features/filesystems, which are very likely to be dropped in
the half way.

And providing such info in the patch is very helpful to reviewers.

> >
> > Hence I ask that you merge bcachefs support to help the process of
> > getting bcachefs suport upstream.

Sure, bcachefs looks promising to me now :)

>
> /me notes that both Eryu and Dave have been willing to merge
> surprisingly large quantities of code for XFS reflink and online fsck
> long before either of those features landed in mainline, so I think it's

Because I know you and the xfs commnity will work on it continuously and
very unlikely make the new tests dead code :)

Thanks,
Eryu

> perfectly fine to merge Kent's relatively small changes to enable
> 'FSTYP=bcachefs'.
>
> (With all of Eryu's review comments fixed, obviously...)
>
> --D
>
> > Cheers,
> >
> > Dave.
> > --
> > Dave Chinner
> > david@fromorbit.com