#! /bin/bash
# SPDX-License-Identifier: GPL-2.0
# Copyright (c) 2017 Fujitsu.  All Rights Reserved.
#
# 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().
#
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
_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