Re: Calltrace in dm-snapshot in 2.6.27 kernel

["aluno3@poczta.onet.pl" <aluno3@poczta.onet.pl>]

Hi

I used your patch and I ran test the same workload. After a few hours
test, everything is OK. Is it possible? Test is still running.When I get
something wrong from kernel I write to You again.



Mikulas Patocka wrote:
> Hi
>
> Run the same workload and try this patch (also keep the previous patch 
> applied).
>
> Note, that the patch is not correct (it leaks a little bit of memory when 
> you deactivate a snapshot, also it will cause an error if you rmmod 
> dm-snapshot), I just want to see if you get any more crashes with this.
>
> Mikulas
>
>   
>> My workload in case of 32b involved only one volume and 3 snapshots to
>> this volume. I wrote only to origin volume (with use fstress) and I
>> created and deleted these snapshots from time to time. Snapshots was
>> mount with rw option.
>>
>> In case 64b I had 2 volume and 10 snapshots for each volume.I created
>> and deleted these snapshots from time to time as well. I wrote only to
>> origin volumes (with use dd)
>>
>> I don`t remember exactly but in case test with 1 snapshot per volume all
>> was working correctly through a few hours and I stopped this test but in
>> case my above tests system was working correctly through a few minutes.
>>  
>> Mikulas Patocka wrote:
>>     
>>>> Hi Mikulas
>>>>
>>>> I send to You (in attachment) files from both kernels.Thank You for help
>>>>
>>>> Best
>>>>     
>>>>         
>>> Thanks. Does your workload involve just one snapshot of a given volume, or 
>>> do you have more snapshots of the same volume? Do you write only to origin 
>>> or to both origin and the snapshot or only to the snapshot?
>>>
>>> I will send you some patch with more debug tests soon, just answer these 
>>> questions first, so that I can make it.
>>>
>>> Mikulas
>>>       
>
> ---
>  drivers/md/dm-snap.c |    4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> Index: linux-2.6.27-clean/drivers/md/dm-snap.c
> ===================================================================
> --- linux-2.6.27-clean.orig/drivers/md/dm-snap.c	2008-10-21 23:38:49.000000000 +0200
> +++ linux-2.6.27-clean/drivers/md/dm-snap.c	2008-10-21 23:39:09.000000000 +0200
> @@ -736,12 +736,12 @@ static void snapshot_dtr(struct dm_targe
>  
>  	__free_exceptions(s);
>  
> -	mempool_destroy(s->pending_pool);
> +	/*mempool_destroy(s->pending_pool);*/
>  
>  	dm_put_device(ti, s->origin);
>  	dm_put_device(ti, s->cow);
>  
> -	kfree(s);
> +	/*kfree(s);*/
>  }
>  
>  /*
>
>