[nginx] Request body: do not create temp file if there's nothing to write.

[Roman Arutyunyan]

details:   https://hg.nginx.org/nginx/rev/97cf8284fd19
branches:  
changeset: 7928:97cf8284fd19
user:      Roman Arutyunyan <arut at nginx.com>
date:      Fri Sep 10 12:59:22 2021 +0300
description:
Request body: do not create temp file if there's nothing to write.

Do this only when the entire request body is empty and
r->request_body_in_file_only is set.

The issue manifested itself with missing warning "a client request body is
buffered to a temporary file" when the entire rb->buf is full and all buffers
are delayed by a filter.

diffstat:

 src/http/ngx_http_request_body.c |  2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diffs (12 lines):

diff -r 7189cb2b4c5d -r 97cf8284fd19 src/http/ngx_http_request_body.c
--- a/src/http/ngx_http_request_body.c	Tue Sep 14 12:12:02 2021 +0300
+++ b/src/http/ngx_http_request_body.c	Fri Sep 10 12:59:22 2021 +0300
@@ -1309,7 +1309,7 @@ ngx_http_request_body_save_filter(ngx_ht
 
     if (rb->rest > 0) {
 
-        if (rb->buf && rb->buf->last == rb->buf->end
+        if (rb->bufs && rb->buf && rb->buf->last == rb->buf->end
             && ngx_http_write_request_body(r) != NGX_OK)
         {
             return NGX_HTTP_INTERNAL_SERVER_ERROR;