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

[Petr Vorel]

Hi all,

> 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 :)
Yw, we appreciate very much your work maintaining inotify/fanotify tests.


> > 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?)

Sure, that should work, but as feature detection works reliably
(tested on v5.17 and v5.18) I'd keep it as is. If problems turn out we can
always put this detection.

> 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.
Sure.

Kind regards,
Petr

> Thanks,
> Amir.