From 0c280d4d99e93d2fd9120a7ec93c0997d372adb4 Mon Sep 17 00:00:00 2001 From: Richard van der Hoff Date: Fri, 20 Apr 2018 11:10:04 +0100 Subject: [PATCH] Reinstate linearizer for federation_server.on_context_state_request --- synapse/federation/federation_server.py | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) diff --git a/synapse/federation/federation_server.py b/synapse/federation/federation_server.py index d1611f39a9..12843fe179 100644 --- a/synapse/federation/federation_server.py +++ b/synapse/federation/federation_server.py @@ -211,11 +211,17 @@ class FederationServer(FederationBase): if not in_room: raise AuthError(403, "Host not in room.") - resp = yield self._state_resp_cache.wrap( - (room_id, event_id), - self._on_context_state_request_compute, - room_id, event_id, - ) + # we grab the linearizer to protect ourselves from servers which hammer + # us. In theory we might already have the response to this query + # in the cache so we could return it without waiting for the linearizer + # - but that's non-trivial to get right, and anyway somewhat defeats + # the point of the linearizer. + with (yield self._server_linearizer.queue((origin, room_id))): + resp = yield self._state_resp_cache.wrap( + (room_id, event_id), + self._on_context_state_request_compute, + room_id, event_id, + ) defer.returnValue((200, resp))