generic: multi-thread freeze/unfreeze test under fsstress

Multi-threads freeze/unfreeze maybe trigger some bugs, e.g: panic,
hang or data corruption etc. It does't check the return value of
freeze/unfreeze, but it tries to make sure fsstress won't run fails,
and no any other bugs happen.

[eguan: add comment on why we check _scratch_mount failure]

Signed-off-by: Zorro Lang <zlang@redhat.com>
Reviewed-by: Eryu Guan <eguan@redhat.com>
Signed-off-by: Eryu Guan <eguan@redhat.com>

tests/generic/390

@@ -0,0 +1,94 @@
+#! /bin/bash
+# FS QA Test 999
+#
+# Multi-threads freeze/unfreeze testing. This's a stress test case,
+# it won't do functional check.
+#
+#-----------------------------------------------------------------------
+# Copyright (c) 2016 Red Hat, Inc.  All Rights Reserved.
+#
+# 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 /
+	# Make sure $SCRATCH_MNT is unfreezed
+	xfs_freeze -u $SCRATCH_MNT 2>/dev/null
+	rm -f $tmp.*
+}
+
+# get standard environment, filters and checks
+. ./common/rc
+. ./common/filter
+
+# remove previous $seqres.full before test
+rm -f $seqres.full
+
+# real QA test starts here
+echo "Silence is golden"
+
+# Modify as appropriate.
+_supported_fs generic
+_supported_os Linux
+_require_scratch
+_require_freeze
+_require_test_program "feature"
+
+_scratch_mkfs >>$seqres.full 2>&1
+# We don't want to freeze/unfreeze root fs if mount scratch dev failed
+_scratch_mount >>$seqres.full 2>&1 || _fail "mount failed"
+
+num_cpus=`$here/src/feature -o`
+
+# Start fsstress in background
+procs=$num_cpus
+if [ $procs -gt 20 ]; then
+	procs=20
+elif [ $procs -le 1 ]; then
+	procs=2
+fi
+nops=1000
+stress_dir="$SCRATCH_MNT/fsstress_test_dir"
+mkdir "$stress_dir"
+fsstress_args=`_scale_fsstress_args -d $stress_dir -p $procs -n $nops $FSSTRESS_AVOID`
+$FSSTRESS_PROG $fsstress_args >>$seqres.full 2>&1 &
+fsstress_pid=$!
+
+# Start multi-threads freeze/unfreeze
+for ((i=0; i<$procs; i++)); do
+	while kill -0 $fsstress_pid 2>/dev/null; do
+		xfs_freeze -f $SCRATCH_MNT 2>/dev/null
+		xfs_freeze -u $SCRATCH_MNT 2>/dev/null
+	done &
+	freeze_pids="$! $freeze_pids"
+done
+
+wait $fsstress_pid
+result=$?
+wait $freeze_pids
+
+# Exit with fsstress return value
+status=$result
+exit

tests/generic/390.out

@@ -0,0 +1,2 @@
+QA output created by 390
+Silence is golden

tests/generic/group

@@ -392,3 +392,4 @@
 387 auto clone
 388 auto log metadata
 389 auto quick acl
+390 auto freeze stress dangerous