bugfix: applied the patch to fix a new regression in nginx 1.7.7's ngx_gzip and ngx_gunzip modules that could lead to request hang when the downstream is slow to write to.

patches/nginx-1.7.7-gzip_gunzip_flush.patch

@@ -0,0 +1,40 @@
+# HG changeset patch
+# User Yichun Zhang <agentzh@gmail.com>
+# Date 1414804249 25200
+#      Fri Oct 31 18:10:49 2014 -0700
+# Node ID 38a74e59f199edafad0a8caae5cfc921ab3302e8
+# Parent  dff86e2246a53b0f4a61935cd5c8c0a0f66d0ca2
+Gzip Gunzip: always flush busy bufs when the incoming chain is NULL.
+
+After the system send buffer is full, NULL incoming chains are used to
+flush pending output upon new write events. The current gzip and gunzip
+filters may intercept NULL chains and keep the data stalling in
+nginx's own send buffers, leading to request hanging (until send
+timeout).
+
+This regression had appeared in nginx 1.7.7.
+
+diff -r dff86e2246a5 -r 38a74e59f199 src/http/modules/ngx_http_gunzip_filter_module.c
+--- a/src/http/modules/ngx_http_gunzip_filter_module.c	Mon Aug 25 13:41:31 2014 +0400
++++ b/src/http/modules/ngx_http_gunzip_filter_module.c	Fri Oct 31 18:10:49 2014 -0700
+@@ -200,7 +200,7 @@ ngx_http_gunzip_body_filter(ngx_http_req
+         }
+     }
+ 
+-    if (ctx->nomem) {
++    if (ctx->nomem || in == NULL) {
+ 
+         /* flush busy buffers */
+ 
+diff -r dff86e2246a5 -r 38a74e59f199 src/http/modules/ngx_http_gzip_filter_module.c
+--- a/src/http/modules/ngx_http_gzip_filter_module.c	Mon Aug 25 13:41:31 2014 +0400
++++ b/src/http/modules/ngx_http_gzip_filter_module.c	Fri Oct 31 18:10:49 2014 -0700
+@@ -373,7 +373,7 @@ ngx_http_gzip_body_filter(ngx_http_reque
+         r->connection->buffered |= NGX_HTTP_GZIP_BUFFERED;
+     }
+ 
+-    if (ctx->nomem) {
++    if (ctx->nomem || in == NULL) {
+ 
+         /* flush busy buffers */
+ 

util/mirror-tarballs

@@ -277,6 +277,13 @@ if [ "$answer" = "N" ]; then
     echo
 fi
 
+answer=`$root/util/ver-ge "$main_ver" 1.7.7`
+if [ "$answer" = "Y" ]; then
+    echo "$info_txt applying the gzip_gunzip_flush patch for nginx"
+    patch -p1 < $root/patches/nginx-$main_ver-gzip_gunzip_flush.patch || exit 1
+    echo
+fi
+
 rm -f *.patch || exit 1
 
 cd .. || exit 1