rgw: Don't segfault on datalog trim

Synchronous (or yielded, basically other-than AioCompletion trim)
would try to dereference the past-the-end iterator if we were trimming
to a point in the most recent generation.

https://tracker.ceph.com/issues/51661
Signed-off-by: Adam C. Emerson <aemerson@redhat.com>

diff --git a/src/rgw/rgw_datalog.cc b/src/rgw/rgw_datalog.cc
index 1acb04d70928064cdd50160be1ea26bb17e9f224..ddc85802b30e0a02a4ac5df2142194a150da85ac 100644 (file)
--- a/src/rgw/rgw_datalog.cc
+++ b/src/rgw/rgw_datalog.cc
@@ -804,6 +804,8 @@ int DataLogBackends::trim_entries(const DoutPrefixProvider *dpp, int shard_id, s
       r = -ENODATA;
     if (r == -ENODATA && be->gen_id < target_gen)
       r = 0;
+    if (be->gen_id == target_gen)
+      break;
     l.lock();
   };
   return r;