[4.1] edf2a34 Enforce that req.body caching can only be done on the first tour through vcl_recv{}

[Lasse Karstensen]

commit edf2a34932c28da6810659ffd567da3b985e6b41
Author: Poul-Henning Kamp <phk at FreeBSD.org>
Date:   Wed Feb 10 11:19:13 2016 +0000

    Enforce that req.body caching can only be done on the first
    tour through vcl_recv{}

diff --git a/bin/varnishd/cache/cache_req_body.c b/bin/varnishd/cache/cache_req_body.c
index f50621e..63f0ba2 100644
--- a/bin/varnishd/cache/cache_req_body.c
+++ b/bin/varnishd/cache/cache_req_body.c
@@ -199,6 +199,14 @@ VRB_Cache(struct req *req, ssize_t maxsize)
 
 	CHECK_OBJ_NOTNULL(req, REQ_MAGIC);
 
+	/*
+	 * We only allow caching to happen the first time through vcl_recv{}
+	 * where we know we will have no competition or conflicts for the
+	 * updates to req.http.* etc.
+	 */
+	if (req->restarts > 0 && req->req_body_status != REQ_BODY_CACHED)
+		return (-1);
+
 	assert (req->req_step == R_STP_RECV);
 	switch(req->req_body_status) {
 	case REQ_BODY_CACHED: