Re: [PATCH] generic/402: fix for updated behavior of timestamp limits

[Amir Goldstein <amir73il@gmail.com>]

On Wed, Dec 18, 2019 at 10:21 PM Deepa Dinamani <deepa.kernel@gmail.com> wrote:
>
> I looked at this more closely. Here is the patch that added the sysctl
> to the kernel previously: https://lkml.org/lkml/2016/11/2/300.
>
> This was meant to be configurable earlier. That is why this made
> sense. But, now it is not. We unconditionally clamp to the fs limits.
> I looked around to see if we ever expose information about internal
> kernel changes to userspace. This is almost never done. And, this is
> always in the form of maybe a syscall failing. Given that we don't see
> any modified behaviour that the user can point out, I don't think we
> can expose the presence of clamping in the kernel.
>
> fsinfo though exposes a fs max and min that could be useful if we fill
> in an unknown pattern as default:
> https://lwn.net/ml/linux-api/153314004147.18964.11925284995448007945.stgit@warthog.procyon.org.uk/.
>
> I also spoke about this to Arnd, and he also suggested the fsinfo as
> an alternative.
>
> Is it easy to not run the test on older kernels? Otherwise, we just
> have to rely on fsinfo being merged?
>

Is it easy to blacklist the test if that is what you are asking.
How people run their stable kernel tests I don't know.
I believe Sasha is running xfstests to validate stable release
candidate patches.

I don't think there is a clear policy about being friendly to testing
less that master kernels in xfstest (Eryu?), but IMO we should try to
accommodate
this use case, because it is in the best interest of everyone that stable kernel
will be regularly tested with xfstests with as little noisy failures
as possible.

Thanks,
Amir.