#! /bin/bash
# SPDX-License-Identifier: GPL-2.0
# Copyright (c) 2016 Red Hat, Inc.  All Rights Reserved.
#
# FS QA Test 270
#
# Today ro-compat features can't be mounted rw, but a bug allows
# an ro->rw remount transition. This bug has been fixed on linux
# kernel (d0a58e8 xfs: disallow rw remount on fs with unknown
# ro-compat features), and this case is the regression testcase.
#
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.*
}

# 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 xfs
# skip fs check because superblock contains unknown ro-compat features
_require_scratch_nocheck
# Only V5 XFS disallow rw mount/remount with unknown ro-compat features
_require_scratch_xfs_crc

_scratch_mkfs_xfs >>$seqres.full 2>&1

# set the highest bit of features_ro_compat, use it as an unknown
# feature bit. If one day this bit become known feature, please
# change this case.
_scratch_xfs_set_metadata_field "features_ro_compat" "$((2**31))" "sb 0" | \
	grep 'features_ro_compat'

# rw mount with unknown ro-compat feature should fail
echo "rw mount test"
_try_scratch_mount 2>>$seqres.full
if [ $? -eq 0 ]; then
	_fail "rw mount test failed"
fi

# But ro mount should succeed
echo "ro mount test"
_try_scratch_mount -o ro
if [ $? -ne 0 ]; then
	_fail "ro mount test failed"
else
	# no hang/panic is fine
	$FSSTRESS_PROG -d $SCRATCH_MNT -p 4 -n 400 >>$seqres.full 2>&1
fi

# remount as rw, kernel should reject it
echo "rw remount test"
_scratch_remount rw 2>>$seqres.full
if [ $? -eq 0 ]; then
	dmesg | tail -n 15 >> $seqres.full
	_fail "rw remount test failed"
fi

_scratch_unmount

# success, all done
status=0
exit