tests/generic/446

#! /bin/bash
# FS QA Test No. 446
#
# Regression test for commit:
# 04197b3 ("xfs: don't BUG() on mixed direct and mapped I/O")
#
# This case tests a race between a direct I/O read and a
# mapped write to a hole in a file.  On xfs filesystem, it
# will trigger a BUG_ON().
#
#-----------------------------------------------------------------------
# Copyright (c) 2017 Fujitsu.  All Rights Reserved.
# Author: Xiao Yang <yangx.jy@cn.fujitsu.com>
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License as
# published by the Free Software Foundation.
#
# This program is distributed in the hope that it would be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write the Free Software Foundation,
# Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
#-----------------------------------------------------------------------

seq=`basename $0`
seqres=$RESULT_DIR/$seq
echo "QA output created by $seq"

here=`pwd`
tmp=/tmp/$$
status=1    # failure is the default!
trap "_cleanup; exit \$status" 0 1 2 3 15

_cleanup()
{
	rm -rf $tmp.*
}

# get standard environment and checks
. ./common/rc
. ./common/filter

# real QA test starts here
_supported_os Linux
_require_scratch
_require_xfs_io_command "truncate"
_require_xfs_io_command "fpunch"

rm -f $seqres.full

# format and mount
_scratch_mkfs > $seqres.full 2>&1
_scratch_mount >> $seqres.full 2>&1

filesz=$((65536 * 2))

# create a test file with a hole
$XFS_IO_PROG -f -c "truncate $((filesz * 2))" $SCRATCH_MNT/file >> $seqres.full

# run a background dio read to a hole in a loop
for i in `seq 0 999`; do
	$XFS_IO_PROG -d -c "pread 0 $filesz" $SCRATCH_MNT/file > /dev/null 2>&1
done &

dread_pid=$!

# run mapped write to the same hole as dio read
# loop until background dio read exits
while kill -s 0 $dread_pid >/dev/null 2>&1; do
	$XFS_IO_PROG -c "mmap 0 $filesz" -c "mwrite 0 $filesz" $SCRATCH_MNT/file \
		> /dev/null
	$XFS_IO_PROG -c "fpunch 0 $filesz" $SCRATCH_MNT/file > /dev/null
done

wait $dread_pid > /dev/null 2>&1

echo "Silence is golden"

# check dmesg, filtering out expected warnings about mixed mmap/dio
# and umount first in case umount triggers warnings
_scratch_unmount
_check_dmesg _filter_aiodio_dmesg

status=$?
exit