SERVER-32593 Stepdown after failed moveChunk commit shouldn't crash source shard primary

1 files changed, 20 insertions, 0 deletions

diff --git a/src/mongo/db/s/migration_source_manager.cpp b/src/mongo/db/s/migration_source_manager.cpp
index b49cdad4392..6c831b1a0ae 100644
--- a/src/mongo/db/s/migration_source_manager.cpp
+++ b/src/mongo/db/s/migration_source_manager.cpp
@@ -36,6 +36,7 @@
 #include "mongo/db/catalog/catalog_raii.h"
 #include "mongo/db/concurrency/write_conflict_exception.h"
 #include "mongo/db/operation_context.h"
+#include "mongo/db/repl/replication_coordinator.h"
 #include "mongo/db/s/migration_chunk_cloner_source_legacy.h"
 #include "mongo/db/s/migration_util.h"
 #include "mongo/db/s/shard_metadata_util.h"
@@ -477,6 +478,25 @@ Status MigrationSourceManager::commitChunkMetadataOnConfig(OperationContext* opC
             shutdown(waitForShutdown());
         }
 
+        // If we failed to get the latest config optime because we stepped down as primary, then it
+        // is safe to fail without crashing because the new primary will fetch the latest optime
+        // when it recovers the sharding state recovery document, as long as we also clear the
+        // metadata for this collection, forcing subsequent callers to do a full refresh. Check if
+        // this node can accept writes for this collection as a proxy for it being primary.
+        if (!status.isOK()) {
+            AutoGetCollection autoColl(opCtx, getNss(), MODE_IX, MODE_X);
+            if (!repl::ReplicationCoordinator::get(opCtx)->canAcceptWritesFor(opCtx, getNss())) {
+                CollectionShardingState::get(opCtx, getNss())->refreshMetadata(opCtx, nullptr);
+                uassertStatusOK(status.withContext(
+                    str::stream() << "Unable to verify migration commit for chunk: "
+                                  << redact(_args.toString())
+                                  << " because the node's replication role changed. Metadata "
+                                     "was cleared for: "
+                                  << getNss().ns()
+                                  << ", so it will get a full refresh when accessed again."));
+            }
+        }
+
         fassertStatusOK(
             40137,
             status.withContext(