Re: [PATCH 2/3] NFSv4.1 mark layout when already returned

[Benny Halevy <bhalevy@tonian.com>]

On 2012-06-11 13:44, Boaz Harrosh wrote:
> On 06/11/2012 12:56 PM, Benny Halevy wrote:
> 
>>
>> It will for recovering files striped with RAID as the LAYOUTRETURN
>> provides the server with a reliable "commit point" where it knows
>> exactly what was written successfully to each stripe and can make
>> the most efficient decision about recovering it (if needed).
>>
>> Allowing I/O to the stripe post LAYOUTRETURN may result in data
>> corruption due to parity inconsistency.
>>
> 
> 
> The fact of the matter is that we - object guys - Which care about
> LAYOUTRETURN the most, have neglected to notice and fix the current
> situation which is even worse than After Andy's patch. Which will
> send multiple LAYOUTRETURNs on the same layout, and might still
> continue IO on returned layouts.
> 
> Thanks Andy for testing and highlighting the current problem,
> I will prioritized this development internally at Panasas and
> will work on a solution ASAP. I hope one that will satisfy
> all.
> 
> Basically my plan is to postpone the LAYOUTRETURN send to
> when the segment is last referenced, if a flag was set to
> do so, and make sure reference counting is done proper, so
> after flag set the last IO_done will send the LAYOUTRETURN.
> 
> If that is OK with all I hope?

Sounds OK to me.  Thanks!

Benny

> 
>> Benny
>>
> 
> 
> Thanks
> Boaz
>