[nginx] Output chain: zero size buf alerts in ngx_chain_writer().

[Maxim Dounin]

details:   http://hg.nginx.org/nginx/rev/6ab301ddf469
branches:  
changeset: 6045:6ab301ddf469
user:      Maxim Dounin <mdounin at mdounin.ru>
date:      Mon Mar 23 20:56:58 2015 +0300
description:
Output chain: zero size buf alerts in ngx_chain_writer().

Now we log a "zero size buf in chain writer" alert if we encounter a zero
sized buffer in ngx_chain_writer(), and skip the buffer.

diffstat:

 src/core/ngx_output_chain.c |  33 ++++++++++++++++++++++++++++++++-
 1 files changed, 32 insertions(+), 1 deletions(-)

diffs (53 lines):

diff --git a/src/core/ngx_output_chain.c b/src/core/ngx_output_chain.c
--- a/src/core/ngx_output_chain.c
+++ b/src/core/ngx_output_chain.c
@@ -663,7 +663,23 @@ ngx_chain_writer(void *data, ngx_chain_t
 
 #if 1
         if (ngx_buf_size(in->buf) == 0 && !ngx_buf_special(in->buf)) {
+
+            ngx_log_error(NGX_LOG_ALERT, ctx->pool->log, 0,
+                          "zero size buf in chain writer "
+                          "t:%d r:%d f:%d %p %p-%p %p %O-%O",
+                          in->buf->temporary,
+                          in->buf->recycled,
+                          in->buf->in_file,
+                          in->buf->start,
+                          in->buf->pos,
+                          in->buf->last,
+                          in->buf->file,
+                          in->buf->file_pos,
+                          in->buf->file_last);
+
             ngx_debug_point();
+
+            continue;
         }
 #endif
 
@@ -691,9 +707,24 @@ ngx_chain_writer(void *data, ngx_chain_t
 
 #if 1
         if (ngx_buf_size(cl->buf) == 0 && !ngx_buf_special(cl->buf)) {
+
+            ngx_log_error(NGX_LOG_ALERT, ctx->pool->log, 0,
+                          "zero size buf in chain writer "
+                          "t:%d r:%d f:%d %p %p-%p %p %O-%O",
+                          cl->buf->temporary,
+                          cl->buf->recycled,
+                          cl->buf->in_file,
+                          cl->buf->start,
+                          cl->buf->pos,
+                          cl->buf->last,
+                          cl->buf->file,
+                          cl->buf->file_pos,
+                          cl->buf->file_last);
+
             ngx_debug_point();
+
+            continue;
         }
-
 #endif
 
         size += ngx_buf_size(cl->buf);