From f182fd7ee3b3efda3046e981a459a3dc83f75719 Mon Sep 17 00:00:00 2001
From: Till Faelligen <2353100+S7evinK@users.noreply.github.com>
Date: Tue, 3 Jan 2023 09:09:26 +0100
Subject: [PATCH] Hopefully fix backfilling

---
 federationapi/routing/backfill.go               | 2 +-
 roomserver/internal/perform/perform_backfill.go | 2 ++
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/federationapi/routing/backfill.go b/federationapi/routing/backfill.go
index 8da486dde..272f5e9d8 100644
--- a/federationapi/routing/backfill.go
+++ b/federationapi/routing/backfill.go
@@ -83,7 +83,7 @@ func Backfill(
 			"": eIDs,
 		},
 		ServerName:  request.Origin(),
-		VirtualHost: request.Origin(),
+		VirtualHost: request.Destination(),
 	}
 	if req.Limit, err = strconv.Atoi(limit); err != nil {
 		util.GetLogger(httpReq.Context()).WithError(err).Error("strconv.Atoi failed")
diff --git a/roomserver/internal/perform/perform_backfill.go b/roomserver/internal/perform/perform_backfill.go
index 069f017a9..aea9fabde 100644
--- a/roomserver/internal/perform/perform_backfill.go
+++ b/roomserver/internal/perform/perform_backfill.go
@@ -56,6 +56,7 @@ func (r *Backfiller) PerformBackfill(
 	// TODO: we could be more sensible and fetch as many events we already have then request the rest
 	//       which is what the syncapi does already.
 	if r.IsLocalServerName(request.ServerName) {
+		logrus.Debugf("backfilling via federation: %+v", request)
 		return r.backfillViaFederation(ctx, request, response)
 	}
 	// someone else is requesting the backfill, try to service their request.
@@ -319,6 +320,7 @@ FederationHit:
 			FedClient:          b.fsAPI,
 			RememberAuthEvents: false,
 			Server:             srv,
+			Origin:             b.virtualHost,
 		}
 		res, err := c.StateIDsBeforeEvent(ctx, targetEvent)
 		if err != nil {