#! /bin/bash
# FS QA Test 036
#
# Test mount error cases with exclusive directories
#
# Overlayfs is often used to mount several mounts that share a single
# lower dir, but every overlayfs mount should have its own private
# upperdir and private workdir.
#
# Overlayfs mount on kernel <= v4.12 does not check if upper/work dirs
# are currently in-use by another overlayfs mount on the system and bad
# things can happen with such configuration.
#
# Expect EBUSY when trying to mount overlay when:
# - Upper dir is in-use by another overlay mount
# - Work dir is in-use by another overlay mount
#
#-----------------------------------------------------------------------
# Copyright (C) 2017 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"

here=`pwd`
tmp=/tmp/$$
status=1	# failure is the default!
trap "_cleanup; exit \$status" 0 1 2 3 15

_cleanup()
{
	cd /
	rm -f $tmp.*
	# unmount the two extra mounts in case they did not fail
	$UMOUNT_PROG $SCRATCH_MNT 2>/dev/null
	$UMOUNT_PROG $SCRATCH_MNT 2>/dev/null
}

# 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 overlay
_supported_os Linux
_require_scratch

# Remove all files from previous tests
_scratch_mkfs

# Create multiple lowerdirs, upperdirs and workdirs
lowerdir=$OVL_BASE_SCRATCH_MNT/lower
lowerdir2=$OVL_BASE_SCRATCH_MNT/lower2
upperdir=$OVL_BASE_SCRATCH_MNT/upper
upperdir2=$OVL_BASE_SCRATCH_MNT/upper2
workdir=$OVL_BASE_SCRATCH_MNT/workdir
workdir2=$OVL_BASE_SCRATCH_MNT/workdir2
mkdir -p $lowerdir $lowerdir2 $upperdir $upperdir2 $workdir $workdir2

# Mount overlay with lowerdir, upperdir, workdir
_overlay_mount_dirs $lowerdir $upperdir $workdir \
		    overlay1 $SCRATCH_MNT
# Try to mount another overlay with the same upperdir - expect EBUSY
_overlay_mount_dirs $lowerdir2 $upperdir $workdir2 \
		    overlay2 $SCRATCH_MNT 2>&1 | _filter_scratch
# Try to mount another overlay with the same workdir - expect EBUSY
_overlay_mount_dirs $lowerdir2 $upperdir2 $workdir \
		    overlay3 $SCRATCH_MNT 2>&1 | _filter_scratch

# success, all done
status=0
exit