Re: server mode and verify_dump

[Jens Axboe <axboe@kernel.dk>]

On 08/14/2015 01:41 PM, Sitsofe Wheeler wrote:
> On 14 August 2015 at 20:22, Jens Axboe <axboe@kernel.dk> wrote:
>> On 08/14/2015 01:21 PM, Sitsofe Wheeler wrote:
>>>
>>> On 14 August 2015 at 20:17, Jens Axboe <axboe@kernel.dk> wrote:
>>>>
>>>> Right, I suspected that might have been the case. If the header isn't
>>>> valid,
>>>> then fio doesn't dump any contents. One could argue that it would be
>>>> cleaner
>>>
>>>
>>> What do you think it would take to dump a block's worth of data when
>>> encountering a header error during a verify?
>>
>>
>> Without a valid header, we can't re-generate the data. That's why it
>> currently doesn't dump the expected contents if the header verification
>> fails.
>
> I see. Even fixed patterns would be a pain unless they have an
> entirely separate code path. How about just dumping whatever you
> received even if it was just a header's worth?

It's not guaranteed that we could do it. We could always just fake up a 
new header, but we don't know the seed and other important things. It 
would be trivial to dump the received block of data, but that seems a 
bit pointless when we don't have the expected data. Since the 
offset+size is listed in the output, getting the same from 'dd' or a 
similar tool would be easy enough.

But I'm willing to be convinced. Dumping the received data is a quick 
change.

-- 
Jens Axboe