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>
(cherry picked from commit 61152ac29654a819eb961e5fc2d7f63b706e15c9)

Conflicts:
	src/osd/PeeringState.h
	  - The RemoteBackfillReserved still in src/osd/PG.h in nautilus.
            Manually backport this fix to src/osd/PG.h

diff --git a/src/osd/PG.h b/src/osd/PG.h
index 4857250d073962691272d71da8a02b2b74f11ab0..ae8aa7e7a9e7f5e4d55201b985a99a47febcbcd1 100644 (file)
--- a/src/osd/PG.h
+++ b/src/osd/PG.h
@@ -2471,9 +2471,14 @@ protected:
 
     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();
     };