Re: ioengine=sync issue on Windows

[Jens Axboe <axboe@kernel.dk>]

On 2014-04-03 16:42, Bruce Cran wrote:
>
> On 4/1/2014 9:11 PM, Bruce Cran wrote:
>>
>> On 3/12/2014 10:33 AM, Jens Axboe wrote:
>>> On 03/12/2014 09:41 AM, S�bastien Bouchex Bellomi� wrote:
>>>>
>>>> fio: pid=5144, err=5/file:backend.c:768, func=full resid,
>>>> error=Input/output error
>>>>
>>>> random_read: (groupid=0, jobs=1): err= 5 (file:backend.c:768,
>>>> func=full resid, error=Input/output error): pid=5144: Wed Mar 12
>>>> 16:36:45 2014
>>> Bruce, do you know why that is?
>>>
>>
>> It appears to be because after seeking, there's 92 bytes before a
>> space in the file (i.e. it's a sparse file), and instead of filling
>> the buffer with 0's read() is for some reason returning 0.
>>
>
> I was wrong.  The problem has something to do with fil_io_buffer - and
> in particular __fill_random_buf. The io error disappears if I change the
> line:
>
> *ptr = seed;
> to
> *ptr = 1;
>
> Also, fio-2.0.15 works, while fio-2.1 doesn't.

That makes very little sense... How could the contents of the buffer 
change the behavior?

Could you run a git bisect? Should be quick'n easy, if it's nicely 
reproducible.

-- 
Jens Axboe