diff --git a/src/osd/OSD.cc b/src/osd/OSD.cc
index c40cb6f0796..c84c2098fd0 100644
--- a/src/osd/OSD.cc
+++ b/src/osd/OSD.cc
@@ -5586,6 +5586,9 @@ void OSD::do_command(Connection *con, ceph_tid_t tid, vector<string>& cmd, buffe
       }
     }
 
+    if (osize && bsize > osize)
+      bsize = osize;
+
     dout(1) << " bench count " << count
             << " bsize " << prettybyte_t(bsize) << dendl;
 
diff --git a/src/test/osd/osd-bench.sh b/src/test/osd/osd-bench.sh
index ac40cb0d8cd..f14a35152f7 100755
--- a/src/test/osd/osd-bench.sh
+++ b/src/test/osd/osd-bench.sh
@@ -77,6 +77,16 @@ function TEST_bench() {
     # default values should work
     #
     ceph tell osd.0 bench || return 1
+
+    #
+    # test object_size < block_size
+    ceph tell osd.0 bench 10 14456 4444 3
+    #
+
+    #
+    # test object_size < block_size & object_size = 0(default value)
+    #
+    ceph tell osd.0 bench 1 14456
 }
 
 main osd-bench "$@"