[LTP] [PATCH 2/5] syscalls/fanotify23: Introduce FAN_MARK_EVICTABLE test

[Amir Goldstein]

On Thu, Jun 16, 2022 at 11:36 AM Petr Vorel <pvorel@suse.cz> wrote:
>
> Hi Amir, Jan, all,
>
> > Verify that evictable mark does not pin inode to cache and that
> > drop_caches evicts inode from cache and removes the evictable mark.
>
> > Verify that evictable mark can be upgraded to non-evictable but not
> > downgraded to evictable afterwards.
>
> We have policy for merging tests for rc kernels [1], thus I merged this patch
> (added fanotify23 into runtest/staging).

Cool. I am glad this issue has been sorted out :)

>
> I'll discuss with others what to do with fanotify10 (old test getting new
> functionality for rc kernel).

Please note, fanotify10 already has:

        if (tc->ignored_onchild && tst_kvercmp(5, 9, 0) < 0) {
                tst_res(TCONF, "ignored mask in combination with flag
FAN_EVENT_ON_CHILD"
                                " has undefined behavior on kernel < 5.9");
                return;
        }

We could easily do the same for FAN_MARK_EVICTABLE
and 5.19.0 (although not sure how tst_kvercmp treats 5.19-rc1?)

I doubt that anyone would want to/be able to backport this feature
to older distro kernels, but even if they do, we could remove the
tst_kvercmp mitigation once 5.19.0 is release and leave only the
feature test if someone complains.

Thanks,
Amir.