SERVER-5680 fix Windows accvios due to incorrect recursive locking of MongoFiles

Conflicts:
	db/dur.cpp

1 files changed, 10 insertions, 0 deletions

diff --git a/db/dur.cpp b/db/dur.cpp
index 3e2c3ecea56..b39dea0b5af 100644
--- a/db/dur.cpp
+++ b/db/dur.cpp
@@ -434,7 +434,17 @@ namespace mongo {
                 fraction = 1;
             lastRemap = now;
 
+#if defined(_WIN32)
+            // Note that this negatively affects performance.
+            // We must grab the exclusive lock here because remapThePrivateView() on Windows needs
+            // to grab it as well, due to the lack of a non-atomic way to remap a memory mapped file.
+            // See SERVER-5723 for performance improvement.
+            // See SERVER-5680 to see why this code is necessary.
+            RWLockRecursive::Exclusive lk(MongoFile::mmmutex);
+#else
             RWLockRecursive::Shared lk(MongoFile::mmmutex);
+#endif
+
             set<MongoFile*>& files = MongoFile::getAllFiles();
             unsigned sz = files.size();
             if( sz == 0 )