apfstests/tests/overlay/016

#! /bin/bash
# FSQA Test No. 016
#
# Test ro/rw fd data inconsistecies
#
# This simple test demonstrates a known issue with overlayfs:
# - process A opens file F for read
# - process B writes new data to file F
# - process A reads old data from file F
#
#-----------------------------------------------------------------------
#
# Copyright (C) 2016 CTERA Networks. All Rights Reserved.
# Author: Amir Goldstein <amir73il@gmail.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"

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

# real QA test starts here
_supported_fs overlay
_supported_os Linux
_require_scratch

rm -f $seqres.full

_scratch_mkfs >>$seqres.full 2>&1

# Create our test files.
lowerdir=$SCRATCH_DEV/$OVERLAY_LOWER_DIR
mkdir -p $lowerdir
echo "This is old news" > $lowerdir/foo
echo "This is old news" > $lowerdir/bar

_scratch_mount

cd $SCRATCH_MNT

#
# case #1:
# open file for read (rofd)
# open file for write (rwfd)
# write to rwfd
# read from rofd
#
$XFS_IO_PROG << EOF | _filter_xfs_io
open -r foo
open foo
pwrite -S 0x61 0 16
file 0
pread -v 0 16
EOF

#
# case #2:
# mmap MAP_SHARED|PROT_READ of rofd
# write to rwfd
# read from mapped memory
#
$XFS_IO_PROG << EOF | _filter_xfs_io
open -r bar
mmap -r 0 16
open bar
pwrite -S 0x61 0 16
mread -v 0 16
EOF

status=0
exit