osd/PeeringState.h: ignore RemoteBackfillReserved in WaitLocalBackfillReserved

It is possible to dequeue an outstanding RemoteBackfillReserved, though we may have
already released reservations for that backfill target. Currently, if this happens
while we are in WaitLocalBackfillReserved, it can lead to a crash on the primary.
Prevent this by treating this condition as a no-op.

The longer term fix is to add a RELEASE_ACK mechanism, which prevents the primary
from scheduling a backfill retry until all the RELEASE_ACKs have been received.

Fixes: https://tracker.ceph.com/issues/44248
Signed-off-by: Neha Ojha <nojha@redhat.com>

diff --git a/src/osd/PeeringState.h b/src/osd/PeeringState.h
index 4b73182870af8443500d54b6a58252fa4e5a1ad4..59eb5a5a4df036f2f82d5a91abe61733169a35cb 100644 (file)
--- a/src/osd/PeeringState.h
+++ b/src/osd/PeeringState.h
@@ -938,9 +938,14 @@ public:
 
   struct WaitLocalBackfillReserved : boost::statechart::state< WaitLocalBackfillReserved, Active >, NamedState {
     typedef boost::mpl::list<
-      boost::statechart::transition< LocalBackfillReserved, WaitRemoteBackfillReserved >
+      boost::statechart::transition< LocalBackfillReserved, WaitRemoteBackfillReserved >,
+      boost::statechart::custom_reaction< RemoteBackfillReserved >
       > reactions;
     explicit WaitLocalBackfillReserved(my_context ctx);
+    boost::statechart::result react(const RemoteBackfillReserved& evt) {
+      /* no-op */
+      return discard_event();
+    }
     void exit();
   };