diff --git a/tests/ext4/033 b/tests/ext4/033
new file mode 100755
index 00000000..74f1a83d
--- /dev/null
+++ b/tests/ext4/033
@@ -0,0 +1,89 @@
+#! /bin/bash
+# FS QA Test 033
+#
+# Reproduce ext4 block reservation leak when mkfs.ext4 -Obigalloc and
+# mount -odelalloc .
+#
+#-----------------------------------------------------------------------
+# Copyright (c) 2018 Alibaba Group.  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 /
+	rm -f $tmp.*
+}
+
+# get standard environment, filters and checks
+. ./common/rc
+. ./common/filter
+
+# remove previous $seqres.full before test
+rm -f $seqres.full
+
+# real QA test starts here
+
+# Modify as appropriate.
+_supported_fs ext4
+_supported_os Linux
+
+_require_scratch
+_require_scratch_ext4_feature "bigalloc"
+
+_scratch_mkfs -Obigalloc
+
+# explicitly mount with -odelalloc since -onodelalloc won't trigger the
+# mentioned bug.
+_scratch_mount -odelalloc
+
+# case 1: two delayed extents result in leak.
+$XFS_IO_PROG -f -c "pwrite 0 1" -c "pwrite 16k 1" -c "fsync" $SCRATCH_MNT/file1 | _filter_xfs_io
+
+# Since the default cluster size is 64K, and all the writes we've made are in
+# one cluster, thus du is supposed to report 64K.
+echo "du $SCRATCH_MNT/file1 | $AWK_PROG '{print \$1}'" >> $seqres.full
+du $SCRATCH_MNT/file1 | $AWK_PROG '{print $1}' | tee -a $seqres.full
+
+# case 2: (one allocated extent + one delayed extent) result in leak.
+$XFS_IO_PROG -f -c "pwrite 0 1" -c "fsync" -c "pwrite 16k 1" -c "fsync" $SCRATCH_MNT/file2 | _filter_xfs_io
+
+# Since the default cluster size is 64K, and all the writes we've made are in
+# one cluster, thus du is supposed to report 64K.
+echo "du $SCRATCH_MNT/file2 | $AWK_PROG '{print \$1}'" >> $seqres.full
+du $SCRATCH_MNT/file2 | $AWK_PROG '{print $1}' | tee -a $seqres.full
+
+# case 3: (one unwritten extent + one delayed extent) result in leak.
+$XFS_IO_PROG -f -c "falloc 0 1" -c "pwrite 16k 1" -c "fsync" $SCRATCH_MNT/file3 | _filter_xfs_io
+
+# Since the default cluster size is 64K, and all the writes we've made are in
+# one cluster, thus du is supposed to report 64K.
+echo "du $SCRATCH_MNT/file3 | $AWK_PROG '{print \$1}'" >> $seqres.full
+du $SCRATCH_MNT/file3 | $AWK_PROG '{print $1}' | tee -a $seqres.full
+
+
+# success, all done
+status=0
+exit
diff --git a/tests/ext4/033.out b/tests/ext4/033.out
new file mode 100644
index 00000000..7ff3d28f
--- /dev/null
+++ b/tests/ext4/033.out
@@ -0,0 +1,14 @@
+QA output created by 033
+wrote 1/1 bytes at offset 0
+XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 1/1 bytes at offset 16384
+XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+64
+wrote 1/1 bytes at offset 0
+XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 1/1 bytes at offset 16384
+XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+64
+wrote 1/1 bytes at offset 16384
+XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+64
diff --git a/tests/ext4/group b/tests/ext4/group
index 5bd15f82..c0d9df28 100644
--- a/tests/ext4/group
+++ b/tests/ext4/group
@@ -35,6 +35,7 @@
 030 auto quick dax
 031 auto quick dax
 032 auto quick ioctl resize
+033 quick auto
 271 auto rw quick
 301 aio auto ioctl rw stress defrag
 302 aio auto ioctl rw stress defrag
