Hi, On 2021-02-03 15:58:33 -0700, Jens Axboe wrote: > On 2/3/21 3:06 PM, Greg Kroah-Hartman wrote: > > On Wed, Feb 03, 2021 at 01:28:26PM -0800, Andres Freund wrote: > >> On 2021-02-03 14:03:09 +0100, Greg Kroah-Hartman wrote: > >>>> On v5.4.43-101-gbba91cdba612 this fails with > >>>> fio: io_u error on file /mnt/t2/test.0.0: Input/output error: write offset=0, buflen=4096 > >>>> fio: pid=734, err=5/file:io_u.c:1834, func=io_u error, error=Input/output error > >>>> > >>>> whereas previously it worked. libaio still works... > >>>> > >>>> I haven't checked which major kernel version fixed this again, but I did > >>>> verify that it's still broken in 5.4.94 and that 5.10.9 works. > >>>> > >>>> I would suspect it's > >>>> > >>>> commit 4503b7676a2e0abe69c2f2c0d8b03aec53f2f048 > >>>> Author: Jens Axboe <axboe@xxxxxxxxx> > >>>> Date: 2020-06-01 10:00:27 -0600 > >>>> > >>>> io_uring: catch -EIO from buffered issue request failure > >>>> > >>>> -EIO bubbles up like -EAGAIN if we fail to allocate a request at the > >>>> lower level. Play it safe and treat it like -EAGAIN in terms of sync > >>>> retry, to avoid passing back an errant -EIO. > >>>> > >>>> Catch some of these early for block based file, as non-mq devices > >>>> generally do not support NOWAIT. That saves us some overhead by > >>>> not first trying, then retrying from async context. We can go straight > >>>> to async punt instead. > >>>> > >>>> Signed-off-by: Jens Axboe <axboe@xxxxxxxxx> > >>>> > >>>> > >>>> which isn't in stable/linux-5.4.y > >>> > >>> Can you test that if the above commit is added, all works well again? > >> > >> It doesn't apply cleanly, I'll try to resolve the conflict. However, I > >> assume that the revert was for a concrete reason - but I can't quite > >> figure out what b0beb28097fa04177b3769f4bb7a0d0d9c4ae76e was concretely > >> solving, and whether reverting the revert in 5.4 would re-introduce a > >> different problem. > >> > >> commit b0beb28097fa04177b3769f4bb7a0d0d9c4ae76e (tag: block-5.7-2020-05-29, linux-block/block-5.7) > >> Author: Jens Axboe <axboe@xxxxxxxxx> > >> Date: 2020-05-28 13:19:29 -0600 > >> > >> Revert "block: end bio with BLK_STS_AGAIN in case of non-mq devs and REQ_NOWAIT" > >> > >> This reverts commit c58c1f83436b501d45d4050fd1296d71a9760bcb. > >> > >> io_uring does do the right thing for this case, and we're still returning > >> -EAGAIN to userspace for the cases we don't support. Revert this change > >> to avoid doing endless spins of resubmits. > >> > >> Cc: stable@xxxxxxxxxxxxxxx # v5.6 > >> Reported-by: Bijan Mottahedeh <bijan.mottahedeh@xxxxxxxxxx> > >> Signed-off-by: Jens Axboe <axboe@xxxxxxxxx> > >> > >> I suspect it just wasn't aimed at 5.4, and that's that, but I'm not > >> sure. In which case presumably reverting > >> bba91cdba612fbce4f8575c5d94d2b146fb83ea3 would be the right fix, not > >> backporting 4503b7676a2e0abe69c2f2c0d8b03aec53f2f048 et al. Having looked a bit more through the history, I suspect that the reason 5.6 doesn't need c58c1f83436b501d45d4050fd1296d71a9760bcb - which I have confirmed - is that ext4 was converted to the iomap infrastructure in 5.5, but not in 5.4. I've confirmed that the repro I shared upthread triggers in 378f32bab3714f04c4e0c3aee4129f6703805550^ but not in 378f32bab3714f04c4e0c3aee4129f6703805550. > > Ok, can you send a revert patch for this? > > > > But it would be good to get Jens to weigh in on this... > > I'll take a look at this. Thanks. Greetings, Andres Freund
