On Wed, Aug 03, 2016 at 07:30:29PM -0500, Shaun Tancheff wrote:

I think the translation in loop.c is suspicious here:

    "if use DIO && not (a flush_flag or discard_flag)"
should translate to:
    "if use DIO && not ((a flush_flag) || op == discard)"

But in the patch I read:
    "if use DIO && ((not a flush_flag) || op == discard)

Which would have DIO && discards follow the AIO path?

Indeed.  Sorry for missing out on your patch, I just sent a fix
in reply to Dave's other report earlier which is pretty similar to
yours.