On Mon, Jul 20, 2020 at 01:43:43PM +0000, Damien Le Moal wrote:

On 2020/07/20 22:38, Christoph Hellwig wrote:

quoted

On Mon, Jul 20, 2020 at 10:21:17PM +0900, Johannes Thumshirn wrote:

quoted

From: Damien Le Moal <redacted>

The res and res2 fields of struct io_event are signed 64 bits values
(__s64 type). Allow the ki_complete method of struct kiocb to set 64
bits values in these fields by changin its interface from the long type
to long long.

Which doesn't help if the consumers can't deal with these values.
But that shouldn't even be required for using zone append anyway..

Not sure what you mean...

res2 is used to pass back to the user the written file offset, 64bits Bytes
value, for aio case (io_submit()/io_getevent()). The change does not break user
interface at all, no changes needed to any system call. The patch  just enables
passing that 64bit byte offset. The consumer of it would be the user
application, and yes, it does need to know what it is doing. But if it is using
zonefs, likely, the application knows.

Please start a discussion on this ABI on the linux-aio and linux-api
lists.  If we support that for zonefs we should also support it for
other direct I/O writes.  And I'm not sure an API that only works
with aio and not io_uring is going to win a lot of friends these days.