generic: add syncfs test

Inspired by syncfs bug of overlayfs which does not sync dirtyinodes
in underlying filesystem.

Run syncfs and shutdown filesystem(or underlying filesystem of
overlayfs) to check syncfs result.

Signed-off-by: Chengguang Xu <cgxu519@icloud.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Eryu Guan <eguan@redhat.com>

tests/generic/474

@@ -0,0 +1,84 @@
+#! /bin/bash
+# FS QA Test 474
+#
+# Inspired by syncfs bug of overlayfs which does not sync dirty inodes in
+# underlying filesystem.
+#
+# Create a small file then run syncfs and shutdown filesystem(or underlying
+# filesystem of overlayfs) to check syncfs result.
+#
+# Test will be skipped if filesystem(or underlying filesystem of overlayfs)
+# does not support shutdown.
+#
+#-----------------------------------------------------------------------
+# Copyright (c) 2017 Chengguang Xu <cgxu519@icloud.com>
+# 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=0
+trap "_cleanup; exit \$status" 0 1 2 3 15
+
+_cleanup()
+{
+	cd /
+	rm -f $tmp.*
+}
+
+# get standard environment, filters and checks
+. ./common/rc
+. ./common/filter
+
+# remove previous $seqres.full before test
+rm -f $seqres.full
+
+# real QA test starts here
+
+_supported_fs generic
+_supported_os Linux
+_require_fssum
+_require_scratch
+_require_scratch_shutdown
+_require_xfs_io_command "syncfs"
+
+_scratch_mkfs >/dev/null 2>&1
+_scratch_mount
+
+# Background writeback will flush dirty inode by dirty ratio and dirty time
+# period(default 30 seconds), in order to avoid interference from it,
+# run sync before test to make all dirty inodes clean, and it also
+# accelerates syncfs on testing filesystem so that test case can finish
+# in 30 seconds.
+
+sync
+
+$XFS_IO_PROG -f -c "pwrite 0 4K" $SCRATCH_MNT/testfile >/dev/null 2>&1
+
+# fssum used for comparing checksum of test file(data & metedata),
+# exclude checking about atime, block structure, open error.
+$FSSUM_PROG -ugomAcdES -f -w $tmp.fssum $SCRATCH_MNT
+$XFS_IO_PROG -c "syncfs" $SCRATCH_MNT/testfile >/dev/null 2>&1
+_scratch_shutdown
+_scratch_cycle_mount
+$FSSUM_PROG -r $tmp.fssum $SCRATCH_MNT
+
+exit

tests/generic/474.out

@@ -0,0 +1,2 @@
+QA output created by 474
+OK

tests/generic/group

@@ -476,3 +476,4 @@
 471 auto quick rw
 472 auto quick rw
 473 auto quick
+474 auto quick shutdown metadata