generic/471: Remove this broken casev2023.08.27

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
if the ilock cannot be obtained immediately.

Here also a discussion[1] that seems generic/471 has been broken.

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.

[Additional information from Dave Chinner]

We changed how timestamps are updated so that they are aware of
IOCB_NOWAIT. If the IOCB_NOWIAT DIO write now needs to update the
inode timestamps, it will return -EAGAIN instead of doing
potentially blocking operations that require IO to complete (i.e.
taking a transaction reservation).

Hence the first time we go to do a DIO read an inode, it's going to
do an atime update, which now occurrs from an IOCB_NOWAIT context
and we return -EAGAIN....

Yes, we added non-blocking timestamp updates as part of the async
buffered write support, but this was a general XFS IO path change of
behaviour to address a potential blocking point in *all* IOCB_NOWAIT
reads and writes, buffered or direct.

The test is not validating that RWF_NOWAIT is behaving correctly - it
just was a simple operation that kinda exercised RWF_NOWAIT semantics
when we had no other way to test this code. It has outlived it's
original purpose, so it should be removed...

[1]https://lore.kernel.org/linux-xfs/b2865bd6-2346-8f4d-168b-17f06bbedbed@kernel.dk/

Signed-off-by: Yang Xu <xuyang2018.jy@fujitsu.com>
Reviewed-by: Bill O'Donnell <bodonnel@redhat.com>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Zorro Lang <zlang@kernel.org>

2 files changed, 0 insertions, 80 deletions

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)