Skip to content
This repository has been archived by the owner on Apr 26, 2024. It is now read-only.

Faster joins: Fix incompatibility with restricted joins #14882

Merged
merged 6 commits into from
Jan 22, 2023
+140 −81
Merged

Faster joins: Fix incompatibility with restricted joins #14882

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
6 commits
Select commit Hold shift + click to select a range
972b31a
Avoid clearing out forward extremities when doing a second remote join
Jan 20, 2023
4fe16d5
Do a full join when doing a second remote join into a full state room
Jan 20, 2023
a0ee80d
Add lock around partial state flag for rooms
Jan 20, 2023
7fdb3b5
Preserve partial state info when doing a second partial state join
Jan 20, 2023
5a26739
Add newsfile
Jan 20, 2023
a4f53eb
Add a TODO(faster_joins) marker
Jan 22, 2023
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
1 change: 1 addition & 0 deletions changelog.d/14882.bugfix
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1 @@
Faster joins: Fix incompatibility with joins into restricted rooms where no local users have the ability to invite.
5 changes: 5 additions & 0 deletions synapse/federation/federation_client.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1157,6 +1157,11 @@ async def _execute(pdu: EventBase) -> None:
"members_omitted was set, but no servers were listed in the room"
)

if response.members_omitted and not partial_state:
raise InvalidResponseError(
"members_omitted was set, but we asked for full state"
)

return SendJoinResult(
event=event,
state=signed_state,
Expand Down
215 changes: 134 additions & 81 deletions synapse/handlers/federation.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -48,7 +48,6 @@
FederationError,
FederationPullAttemptBackoffError,
HttpResponseException,
LimitExceededError,
NotFoundError,
RequestSendFailed,
SynapseError,
Expand Down Expand Up @@ -182,6 +181,12 @@ def __init__(self, hs: "HomeServer"):
self._partial_state_syncs_maybe_needing_restart: Dict[
str, Tuple[Optional[str], Collection[str]]
] = {}
# A lock guarding the partial state flag for rooms.
# When the lock is held for a given room, no other concurrent code may
# partial state or un-partial state the room.
self._is_partial_state_room_linearizer = Linearizer(
name="_is_partial_state_room_linearizer"
)

# if this is the main process, fire off a background process to resume
# any partial-state-resync operations which were in flight when we
Expand Down Expand Up @@ -599,7 +604,23 @@ async def do_invite_join(

self._federation_event_handler.room_queues[room_id] = []

await self._clean_room_for_join(room_id)
is_host_joined = await self.store.is_host_joined(room_id, self.server_name)

if not is_host_joined:
# We may have old forward extremities lying around if the homeserver left
# the room completely in the past. Clear them out.
#
# Note that this check-then-clear is subject to races where
# * the homeserver is in the room and stops being in the room just after
# the check. We won't reset the forward extremities, but that's okay,
# since they will be almost up to date.
# * the homeserver is not in the room and starts being in the room just
# after the check. This can't happen, since `RoomMemberHandler` has a
# linearizer lock which prevents concurrent remote joins into the same
# room.
# In short, the races either have an acceptable outcome or should be
# impossible.
await self._clean_room_for_join(room_id)

try:
# Try the host we successfully got a response to /make_join/
Expand All @@ -611,91 +632,115 @@ async def do_invite_join(
except ValueError:
pass

ret = await self.federation_client.send_join(
host_list, event, room_version_obj
)

event = ret.event
origin = ret.origin
state = ret.state
auth_chain = ret.auth_chain
auth_chain.sort(key=lambda e: e.depth)

logger.debug("do_invite_join auth_chain: %s", auth_chain)
logger.debug("do_invite_join state: %s", state)

logger.debug("do_invite_join event: %s", event)
async with self._is_partial_state_room_linearizer.queue(room_id):
already_partial_state_room = await self.store.is_partial_state_room(
room_id
)

# if this is the first time we've joined this room, it's time to add
# a row to `rooms` with the correct room version. If there's already a
# row there, we should override it, since it may have been populated
# based on an invite request which lied about the room version.
#
# federation_client.send_join has already checked that the room
# version in the received create event is the same as room_version_obj,
# so we can rely on it now.
#
await self.store.upsert_room_on_join(
room_id=room_id,
room_version=room_version_obj,
state_events=state,
)
ret = await self.federation_client.send_join(
host_list,
event,
room_version_obj,
# Perform a full join when we are already in the room and it is a
# full state room, since we are not allowed to persist a partial
# state join event in a full state room. In the future, we could
# optimize this by always performing a partial state join and
# computing the state ourselves or retrieving it from the remote
# homeserver if necessary.
#
# There's a race where we leave the room, then perform a full join
# anyway. This should end up being fast anyway, since we would
# already have the full room state and auth chain persisted.
partial_state=not is_host_joined or already_partial_state_room,
)

if ret.partial_state:
# Mark the room as having partial state.
# The background process is responsible for unmarking this flag,
# even if the join fails.
await self.store.store_partial_state_room(
event = ret.event
origin = ret.origin
state = ret.state
auth_chain = ret.auth_chain
auth_chain.sort(key=lambda e: e.depth)

logger.debug("do_invite_join auth_chain: %s", auth_chain)
logger.debug("do_invite_join state: %s", state)

logger.debug("do_invite_join event: %s", event)

# if this is the first time we've joined this room, it's time to add
# a row to `rooms` with the correct room version. If there's already a
# row there, we should override it, since it may have been populated
# based on an invite request which lied about the room version.
#
# federation_client.send_join has already checked that the room
# version in the received create event is the same as room_version_obj,
# so we can rely on it now.
#
await self.store.upsert_room_on_join(
room_id=room_id,
servers=ret.servers_in_room,
device_lists_stream_id=self.store.get_device_stream_token(),
joined_via=origin,
room_version=room_version_obj,
state_events=state,
)

try:
max_stream_id = (
await self._federation_event_handler.process_remote_join(
origin,
room_id,
auth_chain,
state,
event,
room_version_obj,
partial_state=ret.partial_state,
if ret.partial_state and not already_partial_state_room:
# Mark the room as having partial state.
# The background process is responsible for unmarking this flag,
# even if the join fails.
# TODO(faster_joins):
# We may want to reset the partial state info if it's from an
# old, failed partial state join.
# https://github.com/matrix-org/synapse/issues/13000
await self.store.store_partial_state_room(
room_id=room_id,
servers=ret.servers_in_room,
device_lists_stream_id=self.store.get_device_stream_token(),
joined_via=origin,
)
)
except PartialStateConflictError as e:
# The homeserver was already in the room and it is no longer partial
# stated. We ought to be doing a local join instead. Turn the error into
# a 429, as a hint to the client to try again.
# TODO(faster_joins): `_should_perform_remote_join` suggests that we may
# do a remote join for restricted rooms even if we have full state.
logger.error(
"Room %s was un-partial stated while processing remote join.",
room_id,
)
raise LimitExceededError(msg=e.msg, errcode=e.errcode, retry_after_ms=0)
else:
# Record the join event id for future use (when we finish the full
# join). We have to do this after persisting the event to keep foreign
# key constraints intact.
if ret.partial_state:
await self.store.write_partial_state_rooms_join_event_id(
room_id, event.event_id

try:
max_stream_id = (
await self._federation_event_handler.process_remote_join(
origin,
room_id,
auth_chain,
state,
event,
room_version_obj,
partial_state=ret.partial_state,
)
)
finally:
# Always kick off the background process that asynchronously fetches
# state for the room.
# If the join failed, the background process is responsible for
# cleaning up — including unmarking the room as a partial state room.
if ret.partial_state:
# Kick off the process of asynchronously fetching the state for this
# room.
self._start_partial_state_room_sync(
initial_destination=origin,
other_destinations=ret.servers_in_room,
room_id=room_id,
except PartialStateConflictError:
# This should be impossible, since we hold the lock on the room's
# partial statedness.
logger.error(
"Room %s was un-partial stated while processing remote join.",
room_id,
)
raise
else:
# Record the join event id for future use (when we finish the full
# join). We have to do this after persisting the event to keep
# foreign key constraints intact.
if ret.partial_state and not already_partial_state_room:
# TODO(faster_joins):
# We may want to reset the partial state info if it's from
# an old, failed partial state join.
# https://github.com/matrix-org/synapse/issues/13000
await self.store.write_partial_state_rooms_join_event_id(
room_id, event.event_id
)
finally:
# Always kick off the background process that asynchronously fetches
# state for the room.
# If the join failed, the background process is responsible for
# cleaning up — including unmarking the room as a partial state
# room.
if ret.partial_state:
# Kick off the process of asynchronously fetching the state for
# this room.
self._start_partial_state_room_sync(
initial_destination=origin,
other_destinations=ret.servers_in_room,
room_id=room_id,
)

# We wait here until this instance has seen the events come down
# replication (if we're using replication) as the below uses caches.
Expand Down Expand Up @@ -1778,6 +1823,12 @@ async def _sync_partial_state_room(
`initial_destination` is unavailable
room_id: room to be resynced
"""
# Assume that we run on the main process for now.
# TODO(faster_joins,multiple workers)
# When moving the sync to workers, we need to ensure that
DMRobertson marked this conversation as resolved.
Show resolved Hide resolved
# * `_start_partial_state_room_sync` still prevents duplicate resyncs
# * `_is_partial_state_room_linearizer` correctly guards partial state flags
# for rooms between the workers doing remote joins and resync.
assert not self.config.worker.worker_app

# TODO(faster_joins): do we need to lock to avoid races? What happens if other
Expand Down Expand Up @@ -1815,8 +1866,10 @@ async def _sync_partial_state_room(
logger.info("Handling any pending device list updates")
await self._device_handler.handle_room_un_partial_stated(room_id)

logger.info("Clearing partial-state flag for %s", room_id)
success = await self.store.clear_partial_state_room(room_id)
async with self._is_partial_state_room_linearizer.queue(room_id):
logger.info("Clearing partial-state flag for %s", room_id)
success = await self.store.clear_partial_state_room(room_id)

if success:
logger.info("State resync complete for %s", room_id)
self._storage_controllers.state.notify_room_un_partial_stated(
Expand Down