Add bindiff for tests

src/osd/osd_primary_chain.cpp

@@ -369,6 +369,8 @@ std::vector<osd_chain_read_t> osd_t::collect_chained_read_requests(osd_op_t *cur
                 global_bitmap[cur>>3] = global_bitmap[cur>>3] | (part_bitmap[cur>>3] & (1 << (cur&7)));
             }
             // Add request
+            if (cur_op->req.rw.len)
+            {
                 chain_reads.push_back((osd_chain_read_t){
                     .chain_pos = chain_pos,
                     .inode = op_data->read_chain[chain_pos],
@@ -377,6 +379,7 @@ std::vector<osd_chain_read_t> osd_t::collect_chained_read_requests(osd_op_t *cur
                 });
             }
         }
+    }
     return chain_reads;
 }