Re: dm-mq and end_clone_request()

[Laurence Oberman <loberman@redhat.com>]

----- Original Message -----
> From: "Laurence Oberman" <loberman@redhat.com>
> To: "Mike Snitzer" <snitzer@redhat.com>
> Cc: "Bart Van Assche" <bart.vanassche@sandisk.com>, dm-devel@redhat.com, linux-scsi@vger.kernel.org
> Sent: Thursday, August 4, 2016 9:07:28 PM
> Subject: Re: dm-mq and end_clone_request()
> 
> 
> 
> ----- Original Message -----
> > From: "Mike Snitzer" <snitzer@redhat.com>
> > To: "Bart Van Assche" <bart.vanassche@sandisk.com>
> > Cc: dm-devel@redhat.com, "Laurence Oberman" <loberman@redhat.com>,
> > linux-scsi@vger.kernel.org
> > Sent: Thursday, August 4, 2016 7:58:50 PM
> > Subject: Re: dm-mq and end_clone_request()
> > 
> > I've staged another fix, Laurence is seeing success with this added:
> > https://git.kernel.org/cgit/linux/kernel/git/device-mapper/linux-dm.git/commit/?h=dm-4.8&id=d50a6450104c237db1dc75314d17b78c990a8c05
> > 
> > I'll be sending all the fixes I've queued to Linus tonight or early
> > tomorrow (since I'll then be on vacation until Monday 8/15).
> > 
> Hello Bart,
> 
> I applied that patch to your kernel and while I still obviously see all the
> debug logging its no longer failing fio for me.
> I ran 8 loops with 20 parallel fio runs. This was on a different server to
> the one I had been testing on.
> 
> However I am concerned about timing playing a part here here so let us know
> what you find.
> 
> Thanks
> Laurence
Replying to my own message:

Hi Bart, Mike

Further testing has shown we are still exposed here so more investigation is necessary.
The above patch seems to help but I still see sporadic cases of errors escaping up the stack.

I expect you will see the same so more work to do here to figure this out.

Thanks
Laurence