Re: [PATCH AUTOSEL 4.14 25/35] iomap: sub-block dio needs to zeroout beyond EOF

[Sasha Levin]

On Fri, Nov 30, 2018 at 09:22:03AM +0100, Greg KH wrote:
> On Fri, Nov 30, 2018 at 09:40:19AM +1100, Dave Chinner wrote:
> > I stopped my tests at 5 billion ops yesterday (i.e. 20 billion ops
> > aggregate) to focus on testing the copy_file_range() changes, but
> > Darrick's tests are still ongoing and have passed 40 billion ops in
> > aggregate over the past few days.
> >
> > The reason we are running these so long is that we've seen fsx data
> > corruption failures after 12+ hours of runtime and hundreds of
> > millions of ops. Hence the testing for backported fixes will need to
> > replicate these test runs across multiple configurations for
> > multiple days before we have any confidence that we've actually
> > fixed the data corruptions and not introduced any new ones.
> >
> > If you pull only a small subset of the fixes, the fsx will still
> > fail and we have no real way of actually verifying that there have
> > been no regression introduced by the backport.  IOWs, there's a
> > /massive/ amount of QA needed for ensuring that these backports work
> > correctly.
> >
> > Right now the XFS developers don't have the time or resources
> > available to validate stable backports are correct and regression
> > fre because we are focussed on ensuring the upstream fixes we've
> > already made (and are still writing) are solid and reliable.
>
> Ok, that's fine, so users of XFS should wait until the 4.20 release
> before relying on it?  :)

It's getting to the point that with the amount of known issues with XFS
on LTS kernels it makes sense to mark it as CONFIG_BROKEN.

> I understand your reluctance to want to backport anything, but it really
> feels like you are not even allowing for fixes that are "obviously
> right" to be backported either, even after they pass testing.  Which
> isn't ok for your users.

Do the XFS maintainers expect users to always use the latest upstream
kernel?

--
Thanks,
Sasha