apfstests/tests/overlay/061

#! /bin/bash
# SPDX-License-Identifier: GPL-2.0
# Copyright (C) 2018 CTERA Networks. All Rights Reserved.
#
# FSQA Test No. 061
#
# Test memory mapped data inconsistencies
#
# This is a variant of test overlay/016 with mread instead of pread.
#
# This simple test demonstrates a known issue with overlayfs:
# - process A created shared ro mmap on file F
# - process B created shared rw mmap on file F
# - process B writes new data to shared mmap
# - process A reads old data from shared mmap
#
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
_require_xfs_io_command "open"

rm -f $seqres.full

_scratch_mkfs >>$seqres.full 2>&1

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

_scratch_mount


filter_xfs_io_mmap()
{
	# filter out these lines:
	# [000] 0x7f3d9aece000 - 0x7f3d9aece010 r--  SCRATCH_MNT/foo (0 : 16)
	grep -Fv '[00'
}

#
# mmap MAP_SHARED|PROT_READ of rofd
# mmap MAP_SHARED|PROT_WRITE of rwfd
# write to rw mmap
# read from ro mmap
#
$XFS_IO_PROG -r $SCRATCH_MNT/foo \
	-C "mmap -r 0 16" \
	-C "close" \
	-C "open $SCRATCH_MNT/foo" \
	-C "mmap -w 0 16" \
	-C "close" \
	-C "mwrite -S 0x61 0 16" \
	-C "munmap" \
	-C "mread -v 0 16" \
| _filter_xfs_io | _filter_scratch | filter_xfs_io_mmap

_scratch_cycle_mount

# Verify mmap write after close has persisted through mount cycle
echo "After mount cycle:"
$XFS_IO_PROG -r $SCRATCH_MNT/foo \
	-C "mmap -r 0 16" \
	-C "mread -v 0 16" \
| _filter_xfs_io | _filter_scratch

status=0
exit