Re: [Y2038] [PATCH] utimes: Clamp the timestamps in notify_change()

On Mon, Nov 25, 2019 at 8:46 AM J . Bruce Fields bfields@fieldses.org wrote:

On Sun, Nov 24, 2019 at 09:31:45PM +0200, Amir Goldstein wrote:

...

Push clamping timestamps down the call stack into notify_change(), so in-kernel callers like nfsd and overlayfs will get similar timestamp set behavior as utimes.

So, nfsd has always bypassed timestamp_truncate() and we've never noticed till now? What are the symptoms? (Do timestamps go backwards after cache eviction on filesystems with large time granularity?)

Looks like generic/402 has never run in my tests:

    generic/402     [not run] no kernel support for y2038 sysfs switch

You need this in your xfstest: https://patchwork.kernel.org/patch/11049745/ . The test has been updated recently.

And, you need a change like for overlayfs as Amir pointed out.

-Deepa