AIO read returns negative number for bytes read

[Alireza Haghdoost]

On Sun, Nov 15, 2015 at 7:08 AM, Avi Kivity <avi at scylladb.com> wrote:
> Due to a bug in my program, I initiated a read beyond eof. Specifically, the
> file size is 13002 bytes and the read offset is 13312 (0x3400).
>
> I would expect such a read to return 0 bytes read, but io_getevents returns
> -310, which is suspiciously equal to (13002 - 13312).
>
> I attach a reproducer.
>
> 4.2.5-201.fc22.x86_64
>
> Are my expectations incorrect, or is this a bug in aio or xfs?

I think it is not a bug. This post might be helpful:
http://marc.info/?l=linux-aio&m=142315449930935&w=2