Hi,
On 2020-06-01 19:54:21 +0200, Greg Kroah-Hartman wrote:
> From: Jens Axboe <axboe@xxxxxxxxx>
>
> [ Upstream commit b0beb28097fa04177b3769f4bb7a0d0d9c4ae76e ]
>
> 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>
> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
> ---
> block/blk-core.c | 11 ++++-------
> 1 file changed, 4 insertions(+), 7 deletions(-)
>
This broke io_uring direct-io on ext4 over md.
fallocate -l $((1024*1024*1024)) /srv/part1
fallocate -l $((1024*1024*1024)) /srv/part2
losetup -f /srv/part1
losetup -f /srv/part2
losetup -a # assuming these were loop0/1
mdadm --create -n2 -l stripe -N fast-striped /dev/md/fast-striped /dev/loop0 /dev/loop1
mkfs.ext4 /dev/md/fast-striped
mount /dev/md/fast-striped /mnt/t2
fio --directory=/mnt/t2 --ioengine io_uring --rw write --filesize 1MB --overwrite=1 --name=test --direct=1 --bs=4k
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
Greetings,
Andres Freund
