Re: [dm-devel] [GIT PULL] Queue free fix (was Re: [PATCH] block: Free queue resources at blk_release_queue())

[Hannes Reinecke <hare suse de>]

On 11/29/2011 09:18 PM, Mike Snitzer wrote:
> On Tue, Nov 29 2011 at  7:00am -0500,
> Heiko Carstens <heiko carstens de ibm com> wrote:
> 
>>>>> Hmm. Just to be on the safe side, could you try this one:
>>>>>
>>>>> diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
>>>>> index 5e0090e..e6fad46 100644
>>>>> --- a/drivers/md/dm-mpath.c
>>>>> +++ b/drivers/md/dm-mpath.c
>>>>> @@ -920,8 +920,10 @@ static int multipath_map(struct dm_target *ti,
>>>>> struct reque
>>>>> st *clone,
>>>>>         map_context->ptr = mpio;
>>>>>         clone->cmd_flags |= REQ_FAILFAST_TRANSPORT;
>>>>>         r = map_io(m, clone, mpio, 0);
>>>>> -       if (r < 0 || r == DM_MAPIO_REQUEUE)
>>>>> +       if (r < 0 || r == DM_MAPIO_REQUEUE) {
>>>>>                 mempool_free(mpio, m->mpio_pool);
>>>>> +               map_context->ptr = NULL;
>>>>> +       }
>>>>>
>>>>>         return r;
>>>>>  }
>>>>
>>>> With your patch we haven't been able to reproduce the kernel crash until now.
>>>> Now we "only" run into I/O stalls, which before your patch we also did. But
>>>> repeatedly rebooting and retrying and ignoring the I/O stalls always lead to
>>>> a crash.
>>>> Gonzalo will run a couple of extra rounds so we can have a feeling if at least
>>>> one of the bugs could be fixed with your patch ;)
>>>
>>> Hi,
>>>
>>> Any update after further testing with Hannes' patch?
>>
>> Sorry for the late update, our internal IBM IMAP servers have been down
>> for nearly a week :/
>>
>> So, we were unable to reproduce the original bug with the patch applied
>> during various runs.
> 
> OK, so it seems to be a benenficial change (and obviously correct to
> me).  Hannes, care to formally post your fix to dm-devel so we can get
> it in 3.2-rc?
> 
Yep, will do.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		      zSeries & Storage
hare suse de			      +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: J. Hawn, J. Guild, F. Imendörffer, HRB 16746 (AG Nürnberg)