On Mon, Jul 20, 2020 at 04:48:50PM +0000, Johannes Thumshirn wrote:

On 20/07/2020 15:45, Christoph Hellwig wrote:

quoted

On Mon, Jul 20, 2020 at 10:21:18PM +0900, Johannes Thumshirn wrote:

quoted

On a successful completion, the position the data is written to is
returned via AIO's res2 field to the calling application.

That is a major, and except for this changelog, undocumented ABI
change.  We had the whole discussion about reporting append results
in a few threads and the issues with that in io_uring.  So let's
have that discussion there and don't mix it up with how zonefs
writes data.  Without that a lot of the boilerplate code should
also go away.

OK maybe I didn't remember correctly, but wasn't this all around 
io_uring and how we'd report the location back for raw block device
access?

Report the write offset.  The author seems to be hell bent on making
it block device specific, but that is a horrible idea as it is just
as useful for normal file systems (or zonefs).