tests/overlay/067

#! /bin/bash
# SPDX-License-Identifier: GPL-2.0
# Copyright (C) 2019 CTERA Networks. All Rights Reserved.
#
# FSQA Test No. 067
#
# Test unique st_dev;st_ino on non-samefs setup.
#
# Check that files from middle layer on same fs as upper layer
# are not allowed to export the real inode st_dev;st_ino.
#
# This is a regression test for kernel commit:
#   9c6d8f13e9da ovl: fix corner case of non-unique st_dev;st_ino
#
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

rm -f $seqres.full

# real QA test starts here
_supported_fs overlay
_supported_os Linux
# Use non-default scratch underlying overlay dirs, we need to check
# them explicity after test.
_require_scratch_nocheck
_require_test

# Lower is on test partition
lower=$OVL_BASE_TEST_DIR/$OVL_LOWER-$seq
# Upper/work are on scratch partition
middle=$OVL_BASE_SCRATCH_MNT/$OVL_LOWER
upper=$OVL_BASE_SCRATCH_MNT/$OVL_UPPER
work=$OVL_BASE_SCRATCH_MNT/$OVL_WORK

rm -rf $lower
mkdir $lower

_scratch_mkfs >>$seqres.full 2>&1

realfile=$middle/file
testfile=$SCRATCH_MNT/file

# Create a file on middle layer on same fs as upper layer
echo wrong > $realfile

# Mount an overlay on $SCRATCH_MNT with lower layer on test partition
# and middle and upper layer on scratch partition.
# Disable xino, so not all overlay inodes are on the same st_dev.
_overlay_scratch_mount_dirs $middle:$lower $upper $work -o xino=off || \
	_notrun "cannot mount overlay with xino=off option"

stat $realfile >>$seqres.full
stat $testfile >>$seqres.full

# Diverge the content of the overlay file from its origin
echo right > $testfile

stat $testfile >>$seqres.full

# Expect the overlay file to differ from the original lower file
diff -q $realfile $testfile >>$seqres.full &&
	echo "diff with middle layer file doesn't know right from wrong! (warm cache)"

echo 3 > /proc/sys/vm/drop_caches

stat $testfile >>$seqres.full

# Expect the overlay file to differ from the original lower file
diff -q $realfile $testfile >>$seqres.full &&
	echo "diff with middle layer file doesn't know right from wrong! (cold cache)"

$UMOUNT_PROG $SCRATCH_MNT
# check overlayfs
_overlay_check_scratch_dirs $middle:$lower $upper $work -o xino=off

echo "Silence is golden"
status=0
exit