Re: [GIT PULL] Btrfs updates for 5.8, part 2

[Christoph Hellwig]

On Mon, Jun 15, 2020 at 02:57:01PM +0200, David Sterba wrote:
> On Sun, Jun 14, 2020 at 09:50:17AM -0700, Linus Torvalds wrote:
> > On Sun, Jun 14, 2020 at 4:56 AM David Sterba <dsterba@xxxxxxxx> wrote:
> > >
> > > Reverts are not great, but under current circumstances I don't see
> > > better options.
> > 
> > Pulled. Are people discussing how to make iomap work for everybody?
> > It's a bit sad if we can't have the major filesystems move away from
> > the old buffer head interfaces to a common more modern one..
> 
> Yes, it's fixable and we definitely want to move to iomap. The direct to
> buffered fallback would fix one of the problems, but this would also
> mean that xfs would start doing that. Such change should be treated more
> like a feature development than a bugfix, imposed by another filesystem,
> and xfs people rightfully complained.

We can trivially key that off a flag at least for 5.8.  I suspect the
fallback actually is the right thing for XFS in the long run for that
particular case.