xfstests generic 310: check concurrently of readdir and read on the same directory fd

Check if there are two threads,one keeps calling read() or lseek(), and
the other calling readdir(), both on the same directory fd.

Based on a testcase from Li Zefan <lizefan@huawei.com>.
http://marc.info/?l=linux-kernel&m=136123703211869&w=2

Signed-off-by: Zhao Hongjiang <zhaohongjiang@huawei.com>
Reviewed-by: Rich Johnston <rjohnston@sgi.com>
[rjohnston@sgi.com minor white space fixes and test renumbering]
Signed-off-by: Rich Johnston <rjohnston@sgi.com>

tests/generic/310

@@ -0,0 +1,76 @@
+#! /bin/bash
+# FS QA Test No. 310
+#
+#Check if there are two threads,one keeps calling read() or lseek(), and
+#the other calling readdir(), both on the same directory fd.
+#
+# Based on a testcase from Li Zefan <lizefan@huawei.com>.
+#
+# http://marc.info/?l=linux-kernel&m=136123703211869&w=2
+#
+#-----------------------------------------------------------------------
+# Copyright (c) 2013 HuaWei. 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
+#-----------------------------------------------------------------------
+#
+# creator
+owner=zhaohongjiang@huawei.com
+
+seq=`basename $0`
+echo "QA output created by $seq"
+
+status=1	# failure is the default!
+
+_cleanup()
+{
+	rm -rf $TEST_DIR/tmp
+}
+trap "_cleanup; exit \$status" 0 1 2 3 15
+
+# get standard environment, filters and checks
+. ./common.rc
+. ./common.filter
+
+# real QA test starts here
+_supported_fs generic
+_supported_os Linux
+
+mkdir $TEST_DIR/tmp
+for n in {1..4096}; do
+	touch $TEST_DIR/tmp/$n
+done
+
+_test_read()
+{
+	src/t_readdir_1 $TEST_DIR/tmp &
+	sleep 100
+	killall src/t_readdir_1
+}
+
+_test_lseek()
+{
+	src/t_readdir_2 $TEST_DIR/tmp &
+	sleep 100
+	killall src/t_readdir_2
+}
+
+_test_read
+_test_lseek
+
+# success, all done
+echo "*** done"
+rm -f $seq.full
+status=0
+exit

tests/generic/310.out

@@ -0,0 +1,2 @@
+QA output created by 310
+*** done

tests/generic/group

@@ -112,3 +112,4 @@
 307 auto quick
 308 auto quick
 309 auto quick
+310 auto