--- /dev/null
+#! /bin/bash
+# FS QA Test 059
+#
+# Test multiple origin references to the same lower file.
+#
+# Multiple origin references to the same lower file from upper files that
+# are not hardlinks will falsely return the same st_ino/st_dev for two
+# different overlay files and will cause 'diff' to falsely report that
+# content of files is the same when it is not.
+#
+# This test checks that overlayfs detects and fails lookup of a multiply
+# referenced origin.
+#
+# The check for multiply referenced origin was a by-product of kernel
+# commit 31747eda41ef ("ovl: hash directory inodes for fsnotify")
+#
+#-----------------------------------------------------------------------
+# Copyright (C) 2018 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.*
+}
+
+# Rename lower file to create copy up with origin xattr
+create_origin_ref()
+{
+ local ref=$1
+
+ touch $lowerdir/origin
+
+ # Enabling redirect_dir may seem irrelevant to rename of non-dir,
+ # but with upcoming 'metacopy' feature, redirects will be set also
+ # on non-dir and may also create multiple redirects.
+ _scratch_mount -o redirect_dir=on
+ mv $SCRATCH_MNT/origin $SCRATCH_MNT/$ref
+
+ $UMOUNT_PROG $SCRATCH_MNT
+}
+
+# get standard environment, filters and checks
+. ./common/rc
+. ./common/filter
+
+rm -f $seqres.full
+
+# real QA test starts here
+_supported_fs overlay
+_supported_os Linux
+_require_scratch_nocheck
+_require_scratch_feature redirect_dir
+
+# remove all files from previous runs
+_scratch_mkfs
+
+upperdir=$OVL_BASE_SCRATCH_MNT/$OVL_UPPER
+lowerdir=$OVL_BASE_SCRATCH_MNT/$OVL_LOWER
+
+# Create copied up file with origin xattr
+create_origin_ref ref1
+# Duplicate the copied up file
+cp -a $upperdir/ref1 $upperdir/ref2
+
+# Diverge the content of the two copies of file
+# and the content of two copies of redirected dir
+echo right >> $upperdir/ref1
+echo wrong >> $upperdir/ref2
+
+_scratch_mount -o redirect_dir=on
+
+# If both copies of file use the same st_dev/st_ino in overlay
+# diff won't detect that their content differs
+diff -q $SCRATCH_MNT/ref1 $SCRATCH_MNT/ref2 &>/dev/null && \
+ echo "diff on duplicated upper files doesn't know right from wrong!"
+
+# success, all done
+echo "Silence is golden"
+status=0
+exit