diff --git a/src/core/ngx_buf.c b/src/core/ngx_buf.c
index c3783c4..811f24d 100644
--- a/src/core/ngx_buf.c
+++ b/src/core/ngx_buf.c
@@ -203,16 +203,16 @@
     while (*busy) {
         cl = *busy;
 
-        if (ngx_buf_size(cl->buf) != 0) {
-            break;
-        }
-
         if (cl->buf->tag != tag) {
             *busy = cl->next;
             ngx_free_chain(p, cl);
             continue;
         }
 
+        if (ngx_buf_size(cl->buf) != 0) {
+            break;
+        }
+
         cl->buf->pos = cl->buf->start;
         cl->buf->last = cl->buf->start;