From 85e6352649e734eb0fb9bcbf72fe76ca14a0cbce Mon Sep 17 00:00:00 2001
From: Nic <nic.hollingum@mongodb.com>
Date: Tue, 7 Jan 2025 09:09:42 +1100
Subject: [PATCH] SERVER-98980: Lock globally earlier in validation (#30803)

GitOrigin-RevId: f919575e634ec655da1cbafbabd4033593ecbd84
---
 src/mongo/db/catalog/validate/validate_state.cpp | 4 +---
 src/mongo/db/catalog/validate/validate_state.h   | 5 +++--
 2 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/src/mongo/db/catalog/validate/validate_state.cpp b/src/mongo/db/catalog/validate/validate_state.cpp
index 194fb0421ff..40430acec20 100644
--- a/src/mongo/db/catalog/validate/validate_state.cpp
+++ b/src/mongo/db/catalog/validate/validate_state.cpp
@@ -71,6 +71,7 @@ ValidateState::ValidateState(OperationContext* opCtx,
                              const NamespaceString& nss,
                              ValidationOptions options)
     : ValidationOptions(std::move(options)),
+      _globalLock(opCtx, isBackground() ? MODE_IS : MODE_IX),
       _nss(nss),
       _dataThrottle(opCtx, [&]() { return gMaxValidateMBperSec.load(); }) {
 
@@ -158,8 +159,6 @@ Status ValidateState::initializeCollection(OperationContext* opCtx) {
         shard_role_details::getRecoveryUnit(opCtx)->setTimestampReadSource(
             RecoveryUnit::ReadSource::kProvided, *_validateTs);
 
-        _globalLock.emplace(opCtx, MODE_IS);
-
         try {
             shard_role_details::getRecoveryUnit(opCtx)->preallocateSnapshot();
         } catch (const ExceptionFor<ErrorCodes::SnapshotTooOld>&) {
@@ -177,7 +176,6 @@ Status ValidateState::initializeCollection(OperationContext* opCtx) {
         _collection =
             CollectionPtr(_catalog->establishConsistentCollection(opCtx, _nss, _validateTs));
     } else {
-        _globalLock.emplace(opCtx, MODE_IX);
         _databaseLock.emplace(opCtx, _nss.dbName(), MODE_IX);
         _collectionLock.emplace(opCtx, _nss, MODE_X);
         _catalog = CollectionCatalog::get(opCtx);
diff --git a/src/mongo/db/catalog/validate/validate_state.h b/src/mongo/db/catalog/validate/validate_state.h
index 095a25d6d79..a9cfaf12838 100644
--- a/src/mongo/db/catalog/validate/validate_state.h
+++ b/src/mongo/db/catalog/validate/validate_state.h
@@ -144,9 +144,10 @@ public:
 private:
     ValidateState() = delete;
 
+    // To avoid racing with shutdown/rollback, this lock must be initialized early.
+    Lock::GlobalLock _globalLock;
+
     NamespaceString _nss;
-    // To avoid racing with shutdown.
-    boost::optional<Lock::GlobalLock> _globalLock;
 
     // Locks for foreground validation only.
     boost::optional<AutoGetDb> _databaseLock;