Am 01.08.2017 um 10:35 hat Paolo Bonzini geschrieben: > On 01/08/2017 02:14, John Snow wrote: > > I may need some nudging towards understanding what the right solution > > here is, though. Should the blk_aio_flush assume that there always is a > > root BDS? should it not assume that? > > I think blk_aio_flush is not special. If there is no root BDS, either > you return -ENOMEDIUM, or you crash. But all functions should be doing > the same.
The intended semantics is that they return -ENOMEDIUM (or fail at least). This is how things have always worked, and that it crashes now because of the bdrv_inc_in_flight() was not an intentional change, but simply a bug in the patch. > The former makes sense, but right now blk_prwv for one are crashing if > there is no root BDS so the minimum patch would fix the caller rather > than blk_aio_flush. The synchronous versions don't crash, and bdrv_aio_prwv() would fix all cases if bdrv_inc_in_flight() were moved inside the coroutine; probably right before blk_aio_complete(). This would be more consistent with how the synchronous versions work, too, increasing the in-flight count only by 1 rather than 2 for an AIO request. Kevin
