On Mon, Aug 14, 2023 at 4:04 PM Yang Xu <xuyang2018.jy@xxxxxxxxxxx> wrote:
>
> I remember this case fails on last year becuase of
> kernel commit cae2de69 ("iomap: Add async buffered write support")
> kernel commit 1aa91d9 ("xfs: Add async buffered write support").
> as below:
> pwrite: Resource temporarily unavailable
> wrote 8388608/8388608 bytes at offset 0
> XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
> -RWF_NOWAIT time is within limits.
> +pwrite: Resource temporarily unavailable
> +(standard_in) 1: syntax error
> +RWF_NOWAIT took seconds
>
> So For async buffered write requests, the request will return -EAGAIN
I'm curious about this.
All the xfs_io pwrite calls are being done with Direct IO (-d)
argument, so how does that explain the failure?
> if the ilock cannot be obtained immediately.
What is the ilock? That seems to be xfs specific.
The test passes on btrfs and btrfs supports async buffered writes -
but I'm still puzzled, because the test only does direct IO writes.
Does xfs falls back from direct IO to buffered IO?
>
> Here also a discussion[1] that seems generic/471 has been broken.
Well that discussion doesn't help me understand things. It mentions
some other discussion, presumably with more details. Where's that
other discussion?
Thanks.
>
> Now, I met this problem in my linux distribution, then I found the above
> discussion. IMO, remove this case is ok and then we can avoid to meet this
> false report again.
>
> [1]https://lore.kernel.org/linux-xfs/b2865bd6-2346-8f4d-168b-17f06bbedbed@xxxxxxxxx/
> Signed-off-by: Yang Xu <xuyang2018.jy@xxxxxxxxxxx>
> ---
> tests/generic/471 | 67 -------------------------------------------
> tests/generic/471.out | 13 ---------
> 2 files changed, 80 deletions(-)
> delete mode 100755 tests/generic/471
> delete mode 100644 tests/generic/471.out
>
> diff --git a/tests/generic/471 b/tests/generic/471
> deleted file mode 100755
> index fbd0b12a..00000000
> --- a/tests/generic/471
> +++ /dev/null
> @@ -1,67 +0,0 @@
> -#! /bin/bash
> -# SPDX-License-Identifier: GPL-2.0
> -# Copyright (c) 2017, SUSE Linux Products. All Rights Reserved.
> -#
> -# FS QA Test No. 471
> -#
> -# write a file with RWF_NOWAIT and it would fail because there are no
> -# blocks allocated. Create a file with direct I/O and re-write it
> -# using RWF_NOWAIT. I/O should finish within 50 microsecods since
> -# block allocations are already performed.
> -#
> -. ./common/preamble
> -_begin_fstest auto quick rw
> -
> -# Import common functions.
> -. ./common/populate
> -. ./common/filter
> -. ./common/attr
> -
> -# real QA test starts here
> -_require_odirect
> -_require_test
> -_require_xfs_io_command pwrite -N
> -
> -# Remove reminiscence of previously run tests
> -testdir=$TEST_DIR/$seq
> -if [ -e $testdir ]; then
> - rm -Rf $testdir
> -fi
> -
> -mkdir $testdir
> -
> -# Btrfs is a COW filesystem, so a RWF_NOWAIT write will always fail with -EAGAIN
> -# when writing to a file range except if it's a NOCOW file and an extent for the
> -# range already exists or if it's a COW file and preallocated/unwritten extent
> -# exists in the target range. So to make sure that the last write succeeds on
> -# all filesystems, use a NOCOW file on btrfs.
> -if [ $FSTYP == "btrfs" ]; then
> - _require_chattr C
> - # Zoned btrfs does not support NOCOW
> - _require_non_zoned_device $TEST_DEV
> - touch $testdir/f1
> - $CHATTR_PROG +C $testdir/f1
> -fi
> -
> -# Create a file with pwrite nowait (will fail with EAGAIN)
> -$XFS_IO_PROG -f -d -c "pwrite -N -V 1 -b 1M 0 1M" $testdir/f1
> -
> -# Write the file without nowait
> -$XFS_IO_PROG -f -d -c "pwrite -S 0xaa -W -w -V 1 -b 1M 0 8M" $testdir/f1 | _filter_xfs_io
> -
> -time_taken=`$XFS_IO_PROG -d -c "pwrite -S 0xbb -N -V 1 -b 1M 2M 1M" $testdir/f1 | awk '/^1/ {print $5}'`
> -
> -# RWF_NOWAIT should finish within a short period of time so we are choosing
> -# a conservative value of 50 ms. Anything longer means it is waiting
> -# for something in the kernel which would be a fail.
> -if (( $(echo "$time_taken < 0.05" | bc -l) )); then
> - echo "RWF_NOWAIT time is within limits."
> -else
> - echo "RWF_NOWAIT took $time_taken seconds"
> -fi
> -
> -$XFS_IO_PROG -c "pread -v 0 8M" $testdir/f1 | _filter_xfs_io_unique
> -
> -# success, all done
> -status=0
> -exit
> diff --git a/tests/generic/471.out b/tests/generic/471.out
> deleted file mode 100644
> index ab23272e..00000000
> --- a/tests/generic/471.out
> +++ /dev/null
> @@ -1,13 +0,0 @@
> -QA output created by 471
> -pwrite: Resource temporarily unavailable
> -wrote 8388608/8388608 bytes at offset 0
> -XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
> -RWF_NOWAIT time is within limits.
> -00000000: aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa ................
> -*
> -00200000: bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb ................
> -*
> -00300000: aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa ................
> -*
> -read 8388608/8388608 bytes at offset 0
> -XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
> --
> 2.27.0
>
