overlay: run unionmount testsuite test cases

Add support for running unionmount-testsuite from xfstests.
This requires that unionmount-testsuite is installed under src dir or
that UNIONMOUNT_TESTSUITE variable points to the location of the
testsuite.  It also requires a recent version of unionmount-testsuite
that supports setting mount path via UNIONMOUNT_* environment variables.

Add tests for 2 basic configurations:
- overlay with upper/lower on same fs
- overlay with upper/lower on non same fs

The samefs test uses scratch partition for lower/upper layers.
The nonsamefs test uses the scratch partition for upper layer and the
test partition for lower layer.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>

README.overlay

@@ -50,3 +50,18 @@ In the example above, MOUNT_OPTIONS will be used to mount the base scratch fs,
 TEST_FS_MOUNT_OPTS will be used to mount the base test fs,
 OVERLAY_MOUNT_OPTIONS will be used to mount both test and scratch overlay and
 OVERLAY_FSCK_OPTIONS will be used to check both test and scratch overlay.
+
+
+Unionmount Testsuite
+====================
+
+xfstests can be used as a test harness to run unionmount testsuite test cases
+and provide extended test coverage for overlayfs.
+
+To enable running unionmount testsuite, clone the git repository from:
+  https://github.com/amir73il/unionmount-testsuite.git
+under the xfstests src directory, or set the environment variable
+UNIONMOUNT_TESTSUITE to the local path where the repository was cloned.
+
+Run './check -overlay -g overlay/union' to execute all the unionmount testsuite
+test cases.

common/config

@@ -71,6 +71,8 @@ export OVL_LOWER="ovl-lower"
 export OVL_WORK="ovl-work"
 # overlay mount point parent must be the base fs root
 export OVL_MNT="ovl-mnt"
+# By default unionmount-testsuite is expected under src
+export UNIONMOUNT_TESTSUITE=${UNIONMOUNT_TESTSUITE:=$here/src/unionmount-testsuite}
 
 # From e2fsprogs/e2fsck/e2fsck.h:
 # Exit code used by fsck-type programs

common/overlay

@@ -363,3 +363,56 @@ _repair_overlay_scratch_fs()
 	esac
 	return $res
 }
+
+# This test requires that unionmount testsuite is installed at
+# $UNIONMOUNT_TESTSUITE and that it supports configuring layers and overlay
+# mount paths via UNIONMOUNT_* environment variables.
+_require_unionmount_testsuite()
+{
+	[ -x "$UNIONMOUNT_TESTSUITE/run" ] || \
+		_notrun "unionmount testsuite required."
+
+	# Verify that UNIONMOUNT_* vars are supported
+	local usage=`UNIONMOUNT_MNTPOINT=_ "$UNIONMOUNT_TESTSUITE/run" 2>&1`
+	echo $usage | grep -wq "UNIONMOUNT_MNTPOINT" || \
+		_notrun "newer version of unionmount testsuite required."
+}
+
+_unionmount_testsuite_run()
+{
+	[ "$FSTYP" = overlay ] || \
+		_notrun "Filesystem $FSTYP not supported with unionmount testsuite."
+
+	# Provide the mounted base fs for upper and lower dirs and the
+	# overlay mount point.
+	# unionmount testsuite will perform some tmpfs/bind mounts and the
+	# overlay mount.
+	# test fs is used for lower layer in non-samefs runs.
+	# scratch fs is used for upper layer in non-samefs runs and
+	# as base dir for both layers in samefs runs.
+	export UNIONMOUNT_BASEDIR=$OVL_BASE_SCRATCH_MNT/union/base
+	export UNIONMOUNT_UPPERDIR=$OVL_BASE_SCRATCH_MNT/union/upper
+	export UNIONMOUNT_LOWERDIR=$OVL_BASE_TEST_DIR/union/lower
+	export UNIONMOUNT_MNTPOINT=$SCRATCH_MNT
+
+	_overlay_base_test_mount
+	_scratch_mkfs
+	rm -rf $UNIONMOUNT_BASEDIR $UNIONMOUNT_LOWERDIR $UNIONMOUNT_UPPERDIR
+	mkdir -p $UNIONMOUNT_BASEDIR $UNIONMOUNT_LOWERDIR $UNIONMOUNT_UPPERDIR
+
+	cd $UNIONMOUNT_TESTSUITE
+	echo "run $* ..." > $seqres.full
+	./run $* >> $seqres.full || \
+		echo "unionmount testsuite failed! see $seqres.full for details."
+}
+
+_unionmount_testsuite_cleanup()
+{
+	cd /
+	rm -f $tmp.*
+
+	[ -n "$UNIONMOUNT_MNTPOINT" ] || return 0
+
+	# Cleanup overlay mount after unionmount testsuite run
+	$UMOUNT_PROG $UNIONMOUNT_MNTPOINT 2>/dev/null
+}

tests/overlay/100

@@ -0,0 +1,37 @@
+#! /bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (C) 2020 CTERA Networks. All Rights Reserved.
+#
+# FS QA Test 100
+#
+# Run unionmount testsuite to verify correctness
+# with single lower layer on same fs as upper
+#
+seq=`basename $0`
+seqres=$RESULT_DIR/$seq
+echo "QA output created by $seq"
+
+here=`pwd`
+tmp=/tmp/$$
+status=1	# failure is the default!
+trap "_unionmount_testsuite_cleanup; exit \$status" 0 1 2 3 15
+
+# 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_unionmount_testsuite
+
+_unionmount_testsuite_run --ov --samefs --verify
+
+# success, all done
+echo "Silence is golden"
+status=0
+exit

tests/overlay/100.out

@@ -0,0 +1,2 @@
+QA output created by 100
+Silence is golden

tests/overlay/101

@@ -0,0 +1,37 @@
+#! /bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (C) 2020 CTERA Networks. All Rights Reserved.
+#
+# FS QA Test 101
+#
+# Run unionmount testsuite to verify correctness
+# with single lower layer not on same fs as upper
+#
+seq=`basename $0`
+seqres=$RESULT_DIR/$seq
+echo "QA output created by $seq"
+
+here=`pwd`
+tmp=/tmp/$$
+status=1	# failure is the default!
+trap "_unionmount_testsuite_cleanup; exit \$status" 0 1 2 3 15
+
+# 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_unionmount_testsuite
+
+_unionmount_testsuite_run --ov --verify
+
+# success, all done
+echo "Silence is golden"
+status=0
+exit

tests/overlay/101.out

@@ -0,0 +1,2 @@
+QA output created by 101
+Silence is golden

tests/overlay/group

@@ -75,3 +75,5 @@
 070 auto quick copyup redirect nested
 071 auto quick copyup redirect nested nonsamefs
 072 auto quick copyup hardlink
+100 auto quick union samefs
+101 auto quick union nonsamefs