SERVER-50984 Add CollectionPtr to replace usage of const Collection*

It implements a yieldable interface that is used to re-load the
Collection pointer from the catalog after a yield that released locks.
With lock-free reads and copy-on-write on Collection instances releasing
locks without notifying an AutoGetCollection at a higher level may cause
its pointers to dangle if a MODE_X writer installs a new Collection
instance in the catalog.

CollectionPtr should be passed by const reference so a yield can notify
all the way up.

1 files changed, 3 insertions, 3 deletions

diff --git a/src/mongo/db/repl/rollback_impl.cpp b/src/mongo/db/repl/rollback_impl.cpp
index 365410970ad..a696a57966b 100644
--- a/src/mongo/db/repl/rollback_impl.cpp
+++ b/src/mongo/db/repl/rollback_impl.cpp
@@ -603,12 +603,12 @@ void RollbackImpl::_correctRecordStoreCounts(OperationContext* opCtx) {
                   "Scanning collection to fix collection count",
                   "namespace"_attr = nss.ns(),
                   "uuid"_attr = uuid.toString());
-            AutoGetCollectionForRead autoCollToScan(opCtx, nss);
-            auto collToScan = autoCollToScan.getCollection();
-            invariant(coll == collToScan,
+            AutoGetCollectionForRead collToScan(opCtx, nss);
+            invariant(coll == collToScan.getCollection(),
                       str::stream() << "Catalog returned invalid collection: " << nss.ns() << " ("
                                     << uuid.toString() << ")");
             auto exec = collToScan->makePlanExecutor(opCtx,
+                                                     collToScan.getCollection(),
                                                      PlanYieldPolicy::YieldPolicy::INTERRUPT_ONLY,
                                                      Collection::ScanDirection::kForward);
             long long countFromScan = 0;