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, 5 insertions, 1 deletions

diff --git a/src/mongo/db/ops/delete.h b/src/mongo/db/ops/delete.h
index bb7427f5bb5..bbbe23cbdbc 100644
--- a/src/mongo/db/ops/delete.h
+++ b/src/mongo/db/ops/delete.h
@@ -39,11 +39,15 @@ namespace mongo {
 class Database;
 class OperationContext;
 
+/**
+ * Deletes objects from 'collection' that match the query predicate given by 'pattern'. If 'justOne'
+ * is true, deletes only the first matching object. The PlanExecutor used to do the deletion will
+ * not yield. If 'god' is true, deletes are allowed on system namespaces.
+ */
 long long deleteObjects(OperationContext* opCtx,
                         Collection* collection,
                         const NamespaceString& ns,
                         BSONObj pattern,
-                        PlanExecutor::YieldPolicy policy,
                         bool justOne,
                         bool god = false,
                         bool fromMigrate = false);