[master] 7292f923d Move implementation of transit_buffer to the storage engine

[Nils Goroll]

commit 7292f923dc731292226782a898a804f880567707
Author: Nils Goroll <nils.goroll at uplex.de>
Date:   Wed Jul 17 14:56:42 2024 +0200

    Move implementation of transit_buffer to the storage engine
    
    By the same argument as #4056, storage engines might be able to make a better
    decision on the layout of object bodies if they know the expected length
    upfront, thus the transit buffer limit should be implmented at the storage
    layer.

diff --git a/bin/varnishd/cache/cache_fetch.c b/bin/varnishd/cache/cache_fetch.c
index 34fbb3ae4..ef11def8f 100644
--- a/bin/varnishd/cache/cache_fetch.c
+++ b/bin/varnishd/cache/cache_fetch.c
@@ -597,8 +597,6 @@ vbf_stp_fetchbody(struct worker *wrk, struct busyobj *bo)
 		}
 		AZ(vfc->failed);
 		l = est;
-		if (oc->boc->transit_buffer > 0)
-			l = vmin_t(ssize_t, l, oc->boc->transit_buffer);
 		assert(l >= 0);
 		if (VFP_GetStorage(vfc, &l, &ptr) != VFP_OK) {
 			bo->htc->doclose = SC_RX_BODY;
diff --git a/bin/varnishd/storage/storage_simple.c b/bin/varnishd/storage/storage_simple.c
index 68c780552..9c720aeb4 100644
--- a/bin/varnishd/storage/storage_simple.c
+++ b/bin/varnishd/storage/storage_simple.c
@@ -473,11 +473,15 @@ sml_getspace(struct worker *wrk, struct objcore *oc, ssize_t *sz,
 	struct storage *st;
 
 	CHECK_OBJ_NOTNULL(wrk, WORKER_MAGIC);
+	CHECK_OBJ_NOTNULL(oc, OBJCORE_MAGIC);
+	CHECK_OBJ_NOTNULL(oc->boc, BOC_MAGIC);
 	AN(sz);
 	AN(ptr);
 	if (*sz == 0)
 		*sz = cache_param->fetch_chunksize;
 	assert(*sz > 0);
+	if (oc->boc->transit_buffer > 0)
+		*sz = vmin_t(ssize_t, *sz, oc->boc->transit_buffer);
 
 	o = sml_getobj(wrk, oc);
 	CHECK_OBJ_NOTNULL(o, OBJECT_MAGIC);