On 2/3/21 4:59 PM, Andres Freund wrote: > 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. I checked up on this, and I do see the issue as well. As far as io_uring is concerned, we don't need that revert in 5.4. So I think the right solution here would be to... revert the revert :-) -- Jens Axboe
