[Varnish] #1755: The (struct backend).n_conn counter is never decremented

[Varnish]

#1755: The (struct backend).n_conn counter is never decremented
----------------------+-------------------
 Reporter:  Dridi     |      Owner:
     Type:  defect    |     Status:  new
 Priority:  normal    |  Milestone:
Component:  varnishd  |    Version:  trunk
 Severity:  blocker   |   Keywords:
----------------------+-------------------
 You'll eventually reach the maximum number of connections for a given
 backend and never be able to reach this backend again.

 More on the mailing list:
 - https://www.varnish-cache.org/lists/pipermail/varnish-
 dev/2015-June/008379.html
 - https://www.varnish-cache.org/lists/pipermail/varnish-
 dev/2015-June/008380.html

 Test case:

 {{{
 varnishtest "The (struct backend).n_conn counter is never decremented"

 server s1 {
         rxreq
         txresp

         rxreq
         txresp
 } -start

 varnish v1 -vcl {
         backend s1 {
                 .host = "${s1_addr}";
                 .port = "${s1_port}";
                 .max_connections = 1;
         }
 } -start

 client c1 {
         txreq -url "/foo"
         rxresp
         expect resp.status == 200

         txreq -url "/bar"
         rxresp
         expect resp.status == 200
 } -run

 varnish v1 -expect backend_busy == 0
 }}}

-- 
Ticket URL: <https://www.varnish-cache.org/trac/ticket/1755>
Varnish <https://varnish-cache.org/>
The Varnish HTTP Accelerator