SERVER-25694 Eliminate race in PlanExecutor cleanup.

Ensures that a collection lock is held in at least MODE_IS while
deregistering a PlanExecutor from the cursor manager. Introduces new
PlanExecutor::dispose() and ClientCursor::dispose() methods that must be
called before destruction of those classes, and ensures they are called
before destruction. These calls will thread an OperationContext all the
way through to DocumentSource::dispose() for each stage in a Pipeline,
which will give DocumentSourceCursor a chance to acquire locks and
deregister its PlanExecutor if necessary.

1 files changed, 0 insertions, 11 deletions

diff --git a/src/mongo/db/pipeline/document_source.cpp b/src/mongo/db/pipeline/document_source.cpp
index ec1d8edfcb3..23e98350197 100644
--- a/src/mongo/db/pipeline/document_source.cpp
+++ b/src/mongo/db/pipeline/document_source.cpp
@@ -83,11 +83,6 @@ const char* DocumentSource::getSourceName() const {
     return unknown;
 }
 
-void DocumentSource::setSource(DocumentSource* pTheSource) {
-    verify(!isValidInitialSource());
-    pSource = pTheSource;
-}
-
 intrusive_ptr<DocumentSource> DocumentSource::optimize() {
     return this;
 }
@@ -192,12 +187,6 @@ Pipeline::SourceContainer::iterator DocumentSource::optimizeAt(
     return doOptimizeAt(itr, container);
 }
 
-void DocumentSource::dispose() {
-    if (pSource) {
-        pSource->dispose();
-    }
-}
-
 void DocumentSource::serializeToArray(vector<Value>& array,
                                       boost::optional<ExplainOptions::Verbosity> explain) const {
     Value entry = serialize(explain);