Hold store reference in InternalEngine#performActionWithDirectoryReader(...) (#123010) (#123242)

This method gets called from `InternalEngine#resolveDocVersion(...)`, which gets during indexing (via `InternalEngine.index(...)`).

When `InternalEngine.index(...)` gets invoked, the InternalEngine only ensures that it holds a ref to the engine via Engine#acquireEnsureOpenRef(), but this doesn't ensure whether it holds a reference to the store.

Closes #122974

* Update docs/changelog/123010.yaml

Author: martijnvg

docs/changelog/123010.yaml

@@ -0,0 +1,6 @@
+pr: 123010
+summary: Hold store reference in `InternalEngine#performActionWithDirectoryReader(...)`
+area: Engine
+type: bug
+issues:
+ - 122974

server/src/main/java/org/elasticsearch/index/engine/InternalEngine.java

@@ -3468,7 +3468,9 @@ protected long getPreCommitSegmentGeneration() {
     <T> T performActionWithDirectoryReader(SearcherScope scope, CheckedFunction<DirectoryReader, T, IOException> action)
         throws EngineException {
         assert scope == SearcherScope.INTERNAL : "performActionWithDirectoryReader(...) isn't prepared for external usage";
-        assert store.hasReferences();
+        if (store.tryIncRef() == false) {
+            throw new AlreadyClosedException(shardId + " store is closed", failedEngine.get());
+        }
         try {
             ReferenceManager<ElasticsearchDirectoryReader> referenceManager = getReferenceManager(scope);
             ElasticsearchDirectoryReader acquire = referenceManager.acquire();
@@ -3484,6 +3486,8 @@ <T> T performActionWithDirectoryReader(SearcherScope scope, CheckedFunction<Dire
             ensureOpen(ex); // throw EngineCloseException here if we are already closed
             logger.error("failed to perform action with directory reader", ex);
             throw new EngineException(shardId, "failed to perform action with directory reader", ex);
+        } finally {
+            store.decRef();
         }
     }
 }