On Thu, Feb 04, 2021 at 07:36:18AM -0700, Jens Axboe wrote:
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@kernel.dk > 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@kernel.dk > > > 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@kernel.dk 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@vger.kernel.org # v5.6 Reported-by: Bijan Mottahedeh <bijan.mottahedeh@oracle.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>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 :-)
Thanks for looking at this, I'll go revert the revert now.
greg k-h