ceph · Matan-B · Jul 25, 2024 · Jun 26, 2024 · Jun 27, 2024 · Jul 2, 2024
@@ -89,20 +89,25 @@ seastar::future<> PeeringEvent<T>::with_pg(
     }).then_interruptible([this, pg](auto) {
       return this->template enter_stage<interruptor>(peering_pp(*pg).process);
     }).then_interruptible([this, pg, &shard_services] {
-      return pg->do_peering_event(evt, ctx
-      ).then_interruptible([this] {
+      /* The DeleteSome event invokes PeeringListener::do_delete_work, which
+       * needs to return (without a future) the object to start with on the next
+       * call.  As a consequence, crimson's do_delete_work implementation needs
+       * to use get() for the object listing.  To support that, we wrap
+       * PG::do_peering_event with interruptor::async here.
+       *
+       * Otherwise, it's not ok to yield during peering event handler. Doing so
+       * allows other continuations to observe PeeringState in the middle
+       * of, for instance, a map advance.  The interface *does not* support such
+       * usage.  DeleteSome happens not to trigger that problem so it's ok for
+       * now, but we'll want to remove that as well.
+       * https://tracker.ceph.com/issues/66708
+       */
+      return interruptor::async([this, pg, &shard_services] {
+	pg->do_peering_event(evt, ctx);
+	complete_rctx(shard_services, pg).get();
+      }).then_interruptible([this] {
 	return that()->get_handle().complete();
-      }).then_interruptible([this, pg, &shard_services] {
-	return complete_rctx(shard_services, pg);
       });
-    }).then_interruptible([pg, &shard_services]()
-			  -> typename T::template interruptible_future<> {
-      if (!pg->get_need_up_thru()) {
-	return seastar::now();
-      }
-      return shard_services.send_alive(pg->get_same_interval_since());
-    }).then_interruptible([&shard_services] {
-      return shard_services.send_pg_temp();
     });
   }, [this](std::exception_ptr ep) {
     LOG_PREFIX(PeeringEvent<T>::with_pg);
@@ -128,9 +133,7 @@ PeeringEvent<T>::complete_rctx(ShardServices &shard_services, Ref<PG> pg)
   using interruptor = typename T::interruptor;
   LOG_PREFIX(PeeringEvent<T>::complete_rctx);
   DEBUGI("{}: submitting ctx", *this);
-  return shard_services.dispatch_context(
-    pg->get_collection_ref(),
-    std::move(ctx));
+  return pg->complete_rctx(std::move(ctx));
 }
 
 ConnectionPipeline &RemotePeeringEvent::get_connection_pipeline()

@@ -80,48 +80,33 @@ seastar::future<> PGAdvanceMap::start()
      * See: https://tracker.ceph.com/issues/61744
      */
     from = pg->get_osdmap_epoch();
-    auto fut = seastar::now();
     if (do_init) {
-      fut = pg->handle_initialize(rctx
-      ).then([this] {
-	return pg->handle_activate_map(rctx);
-      });
+      pg->handle_initialize(rctx);
+      pg->handle_activate_map(rctx);
     }
-    return fut.then([this] {
-      ceph_assert(std::cmp_less_equal(*from, to));
-      return seastar::do_for_each(
-	boost::make_counting_iterator(*from + 1),
-	boost::make_counting_iterator(to + 1),
-	[this](epoch_t next_epoch) {
-	  logger().debug("{}: start: getting map {}",
-	                 *this, next_epoch);
-	  return shard_services.get_map(next_epoch).then(
-	    [this] (cached_map_t&& next_map) {
-	      logger().debug("{}: advancing map to {}",
-			     *this, next_map->get_epoch());
-	      return pg->handle_advance_map(next_map, rctx);
-	    });
-	}).then([this] {
-	  return pg->handle_activate_map(rctx).then([this] {
-	    logger().debug("{}: map activated", *this);
-	    if (do_init) {
-	      shard_services.pg_created(pg->get_pgid(), pg);
-	      logger().info("PGAdvanceMap::start new pg {}", *pg);
-	    }
-	    return seastar::when_all_succeed(
-	      pg->get_need_up_thru()
-	      ? shard_services.send_alive(
-		pg->get_same_interval_since())
-	      : seastar::now(),
-	      shard_services.dispatch_context(
-		pg->get_collection_ref(),
-		std::move(rctx)));
+    ceph_assert(std::cmp_less_equal(*from, to));
+    return seastar::do_for_each(
+      boost::make_counting_iterator(*from + 1),
+      boost::make_counting_iterator(to + 1),
+      [this](epoch_t next_epoch) {
+	logger().debug("{}: start: getting map {}",
+		       *this, next_epoch);
+	return shard_services.get_map(next_epoch).then(
+	  [this] (cached_map_t&& next_map) {
+	    logger().debug("{}: advancing map to {}",
+			   *this, next_map->get_epoch());
+	    pg->handle_advance_map(next_map, rctx);
+	    return seastar::now();
 	  });
-	}).then_unpack([this] {
-	  logger().debug("{}: sending pg temp", *this);
-	  return shard_services.send_pg_temp();
-	});
-    });
+      }).then([this] {
+	pg->handle_activate_map(rctx);
+	logger().debug("{}: map activated", *this);
+	if (do_init) {
+	  shard_services.pg_created(pg->get_pgid(), pg);
+	  logger().info("PGAdvanceMap::start new pg {}", *pg);
+	}
+	return pg->complete_rctx(std::move(rctx));
+      });
   }).then([this] {
     logger().debug("{}: complete", *this);
     return handle.complete();

@@ -738,61 +738,49 @@ seastar::future<> PG::read_state(crimson::os::FuturizedStore::Shard* store)
   });
 }
 
-PG::interruptible_future<> PG::do_peering_event(
+void PG::do_peering_event(
   PGPeeringEvent& evt, PeeringCtx &rctx)
 {
   if (peering_state.pg_has_reset_since(evt.get_epoch_requested()) ||
       peering_state.pg_has_reset_since(evt.get_epoch_sent())) {
     logger().debug("{} ignoring {} -- pg has reset", __func__, evt.get_desc());
-    return interruptor::now();
   } else {
     logger().debug("{} handling {} for pg: {}", __func__, evt.get_desc(), pgid);
-    // all peering event handling needs to be run in a dedicated seastar::thread,
-    // so that event processing can involve I/O reqs freely, for example: PG::on_removal,
-    // PG::on_new_interval
-    return interruptor::async([this, &evt, &rctx] {
-      peering_state.handle_event(
-        evt.get_event(),
-        &rctx);
-      peering_state.write_if_dirty(rctx.transaction);
-    });
+    peering_state.handle_event(
+      evt.get_event(),
+      &rctx);
+    peering_state.write_if_dirty(rctx.transaction);
   }
 }
 
-seastar::future<> PG::handle_advance_map(
+void PG::handle_advance_map(
   cached_map_t next_map, PeeringCtx &rctx)
 {
-  return seastar::async([this, next_map=std::move(next_map), &rctx] {
-    vector<int> newup, newacting;
-    int up_primary, acting_primary;
-    next_map->pg_to_up_acting_osds(
-      pgid.pgid,
-      &newup, &up_primary,
-      &newacting, &acting_primary);
-    peering_state.advance_map(
-      next_map,
-      peering_state.get_osdmap(),
-      newup,
-      up_primary,
-      newacting,
-      acting_primary,
-      rctx);
-    osdmap_gate.got_map(next_map->get_epoch());
-  });
-}
-
-seastar::future<> PG::handle_activate_map(PeeringCtx &rctx)
+  vector<int> newup, newacting;
+  int up_primary, acting_primary;
+  next_map->pg_to_up_acting_osds(
+    pgid.pgid,
+    &newup, &up_primary,
+    &newacting, &acting_primary);
+  peering_state.advance_map(
+    next_map,
+    peering_state.get_osdmap(),
+    newup,
+    up_primary,
+    newacting,
+    acting_primary,
+    rctx);
+  osdmap_gate.got_map(next_map->get_epoch());
+}
+
+void PG::handle_activate_map(PeeringCtx &rctx)
 {
-  return seastar::async([this, &rctx] {
-    peering_state.activate_map(rctx);
-  });
+  peering_state.activate_map(rctx);
 }
 
-seastar::future<> PG::handle_initialize(PeeringCtx &rctx)
+void PG::handle_initialize(PeeringCtx &rctx)
 {
-  return seastar::async([this, &rctx] {
-    peering_state.handle_event(PeeringState::Initialize{}, &rctx);
-  });
+  peering_state.handle_event(PeeringState::Initialize{}, &rctx);
 }
 
 void PG::init_collection_pool_opts()