When a streaming delivery of a pass object is terminated prematurely,

we cannot just throw the storage away, we have to wait for the
fetch-thread to go away, possibly in response to a new "abandon"
signal.

Spotted first by:	scoof
Fixes	#1391

bin/varnishd/cache/cache.h

@@ -573,6 +573,7 @@ struct busyobj {
 	/* do_pass is our intent, uncacheable is the result */
 	unsigned		do_pass;
 	unsigned		uncacheable;
+	unsigned		abandon;
 
 	/* Timeouts */
 	double			connect_timeout;

bin/varnishd/cache/cache_fetch_proc.c

@@ -201,6 +201,19 @@ VFP_Fetch_Body(struct busyobj *bo, ssize_t est)
 	}
 
 	do {
+		if (bo->abandon) {
+			/*
+			 * A pass object and delivery was terminted
+			 * We don't fail the fetch, in order for hit-for-pass
+			 * objects to be created.
+			 */
+			AN(bo->fetch_objcore->flags & OC_F_PASS);
+			VSLb(bo->vsl, SLT_FetchError,
+			    "Pass delivery abandonned");
+			vfps = VFP_END;
+			bo->should_close = 1;
+			break;
+		}
 		assert(bo->state != BOS_FAILED);
 		if (st == NULL) {
 			st = VFP_GetStorage(bo, est);

bin/varnishd/cache/cache_http1_deliver.c

@@ -170,11 +170,13 @@ v1d_WriteDirObj(struct req *req)
 
 	while (1) {
 		ois = ObjIter(oi, &ptr, &len);
-		if (ois == OIS_DATA && !VDP_bytes(req, VDP_NULL,  ptr, len))
-			continue;
-		if (ois == OIS_STREAM && !VDP_bytes(req, VDP_FLUSH,  ptr, len))
-			continue;
-		break;
+		if (ois == OIS_DONE) {
+			AZ(len);
+			break;
+		}
+		if (VDP_bytes(req,
+		     ois == OIS_DATA ? VDP_NULL : VDP_FLUSH,  ptr, len))
+			break;
 	}
 	(void)VDP_bytes(req, VDP_FINISH,  NULL, 0);
 	ObjIterEnd(&oi);

bin/varnishd/cache/cache_obj.c

@@ -126,8 +126,11 @@ ObjIterEnd(struct objiter **oi)
 	AN(oi);
 	CHECK_OBJ_NOTNULL((*oi), OBJITER_MAGIC);
 	CHECK_OBJ_NOTNULL((*oi)->obj, OBJECT_MAGIC);
-	if ((*oi)->bo != NULL)
+	if ((*oi)->bo != NULL) {
+		if ((*oi)->obj->objcore->flags & OC_F_PASS)
+			(*oi)->bo->abandon = 1;
 		VBO_DerefBusyObj((*oi)->wrk, &(*oi)->bo);
+	}
 	FREE_OBJ((*oi));
 	*oi = NULL;
 }

bin/varnishd/cache/cache_req_fsm.c

@@ -159,9 +159,16 @@ cnt_deliver(struct worker *wrk, struct req *req)
 
 	V1D_Deliver(req);
 
-	/* No point in saving the body if it is hit-for-pass */
-	if (req->obj->objcore->flags & OC_F_PASS)
+	if (req->obj->objcore->flags & OC_F_PASS) {
+		/*
+		 * No point in saving the body if it is hit-for-pass,
+		 * but we can't yank it until the fetching thread has
+		 * finished/abandonned also.
+		 */
+		while (req->obj->objcore->busyobj != NULL)
+			(void)usleep(100000);
 		STV_Freestore(req->obj);
+	}
 
 	assert(WRW_IsReleased(wrk));
 VSLb(req->vsl, SLT_Debug, "XXX REF %d", req->obj->objcore->refcnt);

bin/varnishtest/tests/r01391.vtc

+varnishtest "client abandoning hit-for-pass"
+
+
+server s1 {
+	rxreq
+	txresp -nolen -hdr "Transfer-Encoding: chunked" -hdr "Set-Cookie: foo=bar"
+	chunked "foo"
+	sema r1 sync 2
+	chunked "bar"
+	delay .1
+	chunkedlen 64
+	delay .1
+	chunkedlen 64
+	chunkedlen 0
+} -start
+
+varnish v1 -vcl+backend {
+} -start
+
+
+client c1 {
+	txreq
+	rxhdrs
+	rxchunk
+	sema r1 sync 2
+} -run
+
+delay 2
+
+server s1 {
+	rxreq
+	txresp
+} -start
+
+client c1 {
+	txreq
+	rxresp
+	expect resp.status == 200
+} -run