tests/generic/451

#! /bin/bash
# SPDX-License-Identifier: GPL-2.0
# Copyright (c) 2017 Red Hat Inc.  All Rights Reserved.
#
# FS QA Test No. 451
#
# Test data integrity when mixing buffered reads and asynchronous
# direct writes a file.
#
. ./common/preamble
_begin_fstest auto quick rw aio

# Import common functions.

# real QA test starts here
_supported_fs generic
_require_test
_require_test_program "feature"
_require_aiodio aio-dio-cycle-write
_require_command "$TIMEOUT_PROG" timeout

TESTFILE=$TEST_DIR/tst-aio-dio-cycle-write.$seq
FSIZE=655360	# bytes

# More read processes can help to reproduce the bug easier, so run
# 2 ~ 20 readers according to the number of CPUs
nr_cpu=`$here/src/feature -o`
loops=$((nr_cpu / 2))
if [ $loops -lt 2 ]; then
	loops=2
elif [ $loops -gt 20 ]; then
	loops=20
fi

keep_reading=$tmp.reading
touch $keep_reading
# buffered reads the file frequently
for ((i=0; i<loops; i++)); do
	while [ -e $keep_reading ]; do
		$XFS_IO_PROG -f -c "pread 0 $FSIZE" $TESTFILE >/dev/null 2>&1
	done &
	reader_pid="$reader_pid $!"
done

# start an aio writer, which does writing loops internally and check
# data integrality.
# For reproduce the original bug, keep testing about 30s will be better,
# So let the AIO_TEST run as many loops as it can, then kill it in 30s.
$TIMEOUT_PROG -s TERM 30s $AIO_TEST -c 999999 -b $FSIZE $TESTFILE >/dev/null

# Remove $keep_reading file to stop the reader cycle
rm -f $keep_reading
wait $reader_pid

echo "Silence is golden"

status=0
exit