Re: Block device direct read EIO handling broken?

Damien Le Moal
2019-08-05T21:27:58Z

On 2019/08/06 6:26, Jens Axboe wrote:
>> In any case, looking again at this code, it looks like there is a
>> problem with dio->size being incremented early, even for fragments
>> that get BLK_QC_T_EAGAIN, because dio->size is being used in
>> blkdev_bio_end_io(). So an incorrect size can be reported to user
>> space in that case on completion (e.g. large asynchronous no-wait dio
>> that cannot be issued in one go).
>>
>> So maybe something like this ? (completely untested)
>
> I think that looks pretty good, I like not double accounting with
> this_size and dio->size, and we retain the old style ordering for the
> ret value.

Do you want a proper patch with real testing backup ? I can send that later today.