SERVER-24569 Maintain rangesToClean and metadataInUse on chunk migrations

This change rewrites the collection metadata refresh mechanism and puts it
entirely under the metadata manager.

1 files changed, 10 insertions, 7 deletions

diff --git a/src/mongo/db/s/sharding_state.h b/src/mongo/db/s/sharding_state.h
index 8975464136d..23e49047981 100644
--- a/src/mongo/db/s/sharding_state.h
+++ b/src/mongo/db/s/sharding_state.h
@@ -49,6 +49,7 @@ namespace mongo {
 class BSONObj;
 class BSONObjBuilder;
 struct ChunkVersion;
+class CollectionMetadata;
 class CollectionShardingState;
 class ConnectionString;
 class OperationContext;
@@ -313,14 +314,16 @@ private:
     void _setInitializationState_inlock(InitializationState newState);
 
     /**
-     * Refreshes collection metadata by asking the config server for the latest information. May or
-     * may not be based on a requested version.
+     * Refreshes collection metadata by asking the config server for the latest information and
+     * returns the latest version at the time the reload was done. This call does network I/O and
+     * should never be called with a lock.
+     *
+     * The metadataForDiff argument indicates that the specified metadata should be used as a base
+     * from which to only load the differences. If nullptr is passed, a full reload will be done.
      */
-    Status _refreshMetadata(OperationContext* txn,
-                            const std::string& ns,
-                            const ChunkVersion& reqShardVersion,
-                            bool useRequestedVersion,
-                            ChunkVersion* latestShardVersion);
+    StatusWith<ChunkVersion> _refreshMetadata(OperationContext* txn,
+                                              const NamespaceString& nss,
+                                              const CollectionMetadata* metadataForDiff);
 
     // Initializes a TaskExecutor for cleaning up orphaned ranges
     void _initializeRangeDeleterTaskExecutor();