Re: All RBD IO stuck after flapping OSD's

[Robin Geuze <robin.geuze@nl.team.blue>]

Hey Ilya,

Took a bit longer than expected, but we finally got around to testing the patches. They seem to do the trick. We did have one stuck rbd dev, however after the 60 second hung task timeout expired that one also continued working. Great work. We ended up testing it on a the Ubuntu 20.04 hwe 5.8 based kernel btw, not 5.4.

Regards,

Robin Geuze

From: Robin Geuze
Sent: 07 July 2021 09:35
To: Ilya Dryomov
Cc: Ceph Development
Subject: Re: All RBD IO stuck after flapping OSD's
    
Hey Ilya,

Thanks so much for the patches, we are planning to test them either this afternoon or tomorrow at the latest, I will let you know the results.

Regards,

Robin Geuze

From: Ilya Dryomov <idryomov@gmail.com>
Sent: 06 July 2021 19:21
To: Robin Geuze
Cc: Ceph Development
Subject: Re: All RBD IO stuck after flapping OSD's
    
On Tue, Jun 29, 2021 at 12:07 PM Ilya Dryomov <idryomov@gmail.com> wrote:
>
> On Tue, Jun 29, 2021 at 10:39 AM Robin Geuze <robin.geuze@nl.team.blue> wrote:
> >
> > Hey Ilya,
> >
> > Do you have any idea on the cause of this bug yet? I tried to dig around a bit myself in the source, but the logic around this locking is very complex, so I couldn't figure out where the problem is.
>
> I do.  The proper fix would indeed be large and not backportable but
> I have a workaround in mind that should be simple enough to backport
> all the way to 5.4.  The trick is making sure that the workaround is
> fine from the exclusive lock protocol POV.
>
> I'll try to flesh it out by the end of this week and report back
> early next week.

Hi Robin,

I CCed you on the patches.  They should apply to 5.4 cleanly.  You
mentioned you have a build farm set up, please take them for a spin.

Thanks,

                Ilya