Re: [LTP] [PATCH v2 2/3] Add fanotify_get_supported_init_flags() helper function

[Petr Vorel <pvorel@suse.cz>]

Hi all,

> On 24. 10. 22 16:34, Amir Goldstein wrote:
> > This is how I would fix the problem:

> > <snip>

> > Give or take using more macros and your nicer flag prints.
> > There is no need for auto-detection of the unsupported kernel flags.

> > If the test case is expected to get to fanotify_mark() (i.e. non-zero tc->mask)
> > EINVAL from fanotify_init() always means "unsupported".

> This would be a good approach if fanotify_init() returned distinct error
> code for "flag not implemented", like ENOTSUP. But when EINVAL is returned
> for both "not implemented" and "wrong use", this has a risk of hiding real
> bugs. That's why I'm trying to detect the actual set of flags implemented in
> the running kernel before running the real tests.
Indeed, that's quite surprising (not really, it was added in 2.6.36 and remember
Jan Kara's talk about dnotify/inotify/fanotify history). I wonder if it's
possible to fix (backward compatibility would suffer).

> And since some flags may be backported to older kernels, generating feature
> sets based on kernel version is not a solution.
I guess even some not-important fix was not backported. I guess features aren't
backported to the stable kernel maybe to enterprise kernels (SLES, RHEL), but
even there I'd guess there are related patches backported, not features. But
maybe I'm wrong. Jan and Amir?

Kind regards,
Petr

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