#! /bin/bash
# SPDX-License-Identifier: GPL-2.0
# Copyright (c) 2016 Facebook.  All Rights Reserved.
#
# FS QA Test 391
#
# Test two threads doing non-overlapping direct I/O in the same extents.
# Motivated by a bug in Btrfs' direct I/O get_block function which would lead
# to spurious -EEXIST failures from direct I/O reads.
#
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()
{
	cd /
	rm -f $tmp.*
	rm -f "$testfile"
}

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

# remove previous $seqres.full before test
rm -f $seqres.full

# real QA test starts here

_supported_fs generic
_supported_os Linux
_require_test
_require_xfs_io_command "falloc"
_require_test_program "dio-interleaved"
_require_odirect

extent_size="$(($(_get_block_size "$TEST_DIR") * 2))"
num_extents=1024
testfile="$TEST_DIR/$$-testfile"

$XFS_IO_PROG -fc "truncate 0" "$testfile"
for ((off = 0; off < num_extents * extent_size; off += extent_size)); do
	$XFS_IO_PROG -c "falloc $off $extent_size" "$testfile"
done

# To reproduce the Btrfs bug, the extent map must not be cached in memory.
sync
echo 3 > /proc/sys/vm/drop_caches

"$here/src/dio-interleaved" "$extent_size" "$num_extents" "$testfile"

echo "Silence is golden"

# success, all done
status=0
exit