http2_send: Track bankrupt streams

Conflicts:
	bin/varnishd/http2/cache_http2.h

bin/varnishd/http2/cache_http2.h

@@ -162,6 +162,8 @@ struct h2_sess {
 
 	struct sess			*sess;
 	int				refcnt;
+	int				open_streams;
+	int				winup_streams;
 	uint32_t			highest_stream;
 	int				goaway;
 	int				bogosity;
@@ -193,7 +195,6 @@ struct h2_sess {
 	VTAILQ_HEAD(,h2_req)		txqueue;
 
 	h2_error			error;
-	int				open_streams;
 
 	// rst rate limit parameters, copied from h2_* parameters
 	vtim_dur			rapid_reset;

bin/varnishd/http2/cache_http2_send.c

@@ -268,6 +268,9 @@ h2_do_window(struct worker *wrk, struct h2_req *r2,
 		r2->t_winupd = VTIM_real();
 		h2_send_rel_locked(h2, r2);
 
+		assert(h2->winup_streams >= 0);
+		h2->winup_streams++;
+
 		while (r2->t_window <= 0 && h2_errcheck(r2, h2) == NULL) {
 			r2->cond = &wrk->cond;
 			(void)h2_cond_wait(r2->cond, h2, r2);
@@ -282,6 +285,10 @@ h2_do_window(struct worker *wrk, struct h2_req *r2,
 			h2_win_charge(r2, h2, w);
 			assert (w > 0);
 		}
+
+		assert(h2->winup_streams > 0);
+		h2->winup_streams--;
+
 		h2_send_get_locked(wrk, h2, r2);
 	}