tests/generic/462

#! /bin/bash
# SPDX-License-Identifier: GPL-2.0
# Copyright (c) 2017 Red Hat.  All Rights Reserved.
#
# FS QA Test 462
#
# This is a regression test for kernel commit
#  ef947b2 x86, mm: fix gup_pte_range() vs DAX mappings
# created by Jeffrey Moyer <jmoyer@redhat.com>
#
# This is reproducible only when testing on pmem device
# which is configured in "memory mode", not in "raw mode".
#
. ./common/preamble
_begin_fstest auto quick dax

# Import common functions.
. ./common/filter

# Modify as appropriate.
_supported_fs generic
_require_test
_require_scratch_dax_mountopt "dax"
_require_test_program "t_mmap_write_ro"
# running by unpriviliged user is not necessary to reproduce
# this bug, just trying to test more.
_require_user

# real QA test starts here

_scratch_mkfs >>$seqres.full 2>&1
_scratch_mount "-o dax"

# remount TEST_DEV wo/ dax
export TEST_FS_MOUNT_OPTS=""
_test_cycle_mount

# prepare a 4k read-only DAX file, save its md5sum
$XFS_IO_PROG -f -c "pwrite -S 0xFF 0 4096" \
	$SCRATCH_MNT/readonlyfile >> $seqres.full 2>&1
chmod 0644  $SCRATCH_MNT/readonlyfile
md5_1="$(_md5_checksum $SCRATCH_MNT/readonlyfile)"

# prepare another 4k non-DAX file
$XFS_IO_PROG -f -c "pwrite -S 0x00 0 4096" \
	$TEST_DIR/${seq}.file >> $seqres.full 2>&1

# allow qa_user access
chown $qa_user $TEST_DIR/${seq}.file

# run test programme, read another file writing into
# the read-only file with mmap, which should fail.
#
# don't use $here/src/t_mmap_write_ro, as we're running it as a regular user,
# and $here may contain path component that a regular user doesn't have search
# permission
_user_do "src/t_mmap_write_ro $TEST_DIR/${seq}.file \
	$SCRATCH_MNT/readonlyfile"

# read-only file should not get updated, md5sum again.
md5_2="$(_md5_checksum $SCRATCH_MNT/readonlyfile)"

[ "$md5_1" != "$md5_2" ] && echo "read only file changed"

# success, all done
status=0
exit