From c2cffb0b0c2aeb5a1ec167b6bc9d68606dba2790 Mon Sep 17 00:00:00 2001
From: Eric Milkie <milkie@10gen.com>
Date: Tue, 8 May 2018 15:40:25 -0400
Subject: [PATCH] Finish the supportsDBLocking implementation.

---
 src/mongo/db/concurrency/lock_state.cpp | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/src/mongo/db/concurrency/lock_state.cpp b/src/mongo/db/concurrency/lock_state.cpp
index 790ba748a0..110e29b9b2 100644
--- a/src/mongo/db/concurrency/lock_state.cpp
+++ b/src/mongo/db/concurrency/lock_state.cpp
@@ -357,7 +357,18 @@ LockResult LockerImpl<IsForMMAPV1>::_lockGlobalBegin(OperationContext* opCtx,
         }
         _modeForTicket = mode;
     }
-    const LockResult result = lockBegin(opCtx, resourceIdGlobal, mode);
+
+    LockMode actualLockMode = mode;
+    if (opCtx) {
+        if (!opCtx->getServiceContext()->getStorageEngine()->supportsDBLocking()) {
+            actualLockMode = isSharedLockMode(mode) ? MODE_S : MODE_X;
+        }
+    } else {
+        // Ensure only Global Exclusive lock requests can omit the operation context.
+        // This is needed at shutdown time, for example.
+        invariant(actualLockMode == MODE_X);
+    }
+    const LockResult result = lockBegin(opCtx, resourceIdGlobal, actualLockMode);
     if (result == LOCK_OK)
         return LOCK_OK;
 
-- 
2.14.3