close connection if putLast failed during fill operation

src/main/java/com/alibaba/druid/pool/DruidDataSource.java

@@ -3823,17 +3823,23 @@ public class DruidDataSource extends DruidAbstractDataSource implements DruidDat
                 throw new SQLException("interrupt", e);
             }
 
+            boolean result;
             try {
                 if (!this.isFillable(toCount)) {
                     JdbcUtils.close(holder.getConnection());
                     LOG.info("fill connections skip.");
                     break;
                 }
-                this.putLast(holder, System.currentTimeMillis());
+                result = this.putLast(holder, System.currentTimeMillis());
                 fillCount++;
             } finally {
                 lock.unlock();
             }
+
+            if (!result) {
+                JdbcUtils.close(holder.getConnection());
+                LOG.info("connection fill failed.");
+            }
         }
 
         if (LOG.isInfoEnabled()) {