title: open() "" failed (2: No such file or directory)
body: <p>When I request a link <code>http://abc.example.com/images/default-thumbnail.jpg</code> a 404 error occurs while seeing the log file output <code>[error] 1244#0: *1 open() "/tmp/upload-dir/images/default-thumbnail.jpg" failed (2: No such file or directory),</code></p>
  
  <p>But in fact this file is there,And the authority is 777</p>
  
  <pre><code>[root@localhost nginx]# ll /tmp/upload-dir/images/default-thumbnail.jpg
  -rwxrwxrwx 1 root root 7592 6月  21 2016 /tmp/upload-dir/images/default-thumbnail.jpg
  </code></pre>
  
  <p>Nginx configuration：</p>
  
  <pre><code>server {
      charset utf-8;
      client_max_body_size 128M;
      sendfile off;
  
      listen 80;
  
      server_name abc.example.com;
  
      access_log  /www/abc/logs/nginx-access.log;
      error_log   /www/abc/logs/nginx-error.log;
  
      root /tmp/upload-dir;
  
      location /images/ {
          autoindex on;
          expires 30d;
      }
  
      location / {
          proxy_pass        http://localhost:8080;
          proxy_set_header  X-Real-IP $remote_addr;
          proxy_set_header  X-Forwarded-For $proxy_add_x_forwarded_for;
          proxy_set_header  Host $http_host;
      }
  
  }
  </code></pre>