On 21/07/2020 07:54, Christoph Hellwig wrote: > On Mon, Jul 20, 2020 at 04:48:50PM +0000, Johannes Thumshirn wrote: >> On 20/07/2020 15:45, Christoph Hellwig wrote: >>> On Mon, Jul 20, 2020 at 10:21:18PM +0900, Johannes Thumshirn wrote: >>>> 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). After having looked into io_uring I don't this there is anything that prevents io_uring from picking up the write offset from ki_complete's res2 argument. As of now io_uring ignores the filed but that can be changed. The reporting of the write offset to user-space still needs to be decided on from an io_uring PoV. So the only thing that needs to be done from a zonefs perspective is documenting the use of res2 and CC linux-aio and linux-abi (including an update of the io_getevents man page). Or am I completely off track now? Thanks, Johannes
