From 18a18189efe036aaa4100c96f1f4c0eb6b4986db Mon Sep 17 00:00:00 2001
From: Masakazu Kitajo <maskit@apache.org>
Date: Fri, 8 Oct 2021 11:07:10 +0900
Subject: [PATCH] Fix a potential H2 stall issue (#8381)

(cherry picked from commit 870b857bbbc1d993d6c66672a09b561c13f087d5)

 Conflicts:
	proxy/http2/Http2ConnectionState.cc
---
 proxy/http2/Http2ConnectionState.cc | 1 +
 1 file changed, 1 insertion(+)

diff --git a/proxy/http2/Http2ConnectionState.cc b/proxy/http2/Http2ConnectionState.cc
index e06b5fdaefa..a486d4567cf 100644
--- a/proxy/http2/Http2ConnectionState.cc
+++ b/proxy/http2/Http2ConnectionState.cc
@@ -1541,6 +1541,7 @@ Http2ConnectionState::send_a_data_frame(Http2Stream *stream, size_t &payload_len
 
   if (this->ua_session->write_avail() == 0) {
     Http2StreamDebug(this->ua_session, stream->get_id(), "Not write avail");
+    this->ua_session->flush();
     return Http2SendDataFrameResult::NOT_WRITE_AVAIL;
   }