1 files changed, 34 insertions, 2 deletions
diff --git a/src/mongo/executor/network_interface_tl.h b/src/mongo/executor/network_interface_tl.h
index 158e4b0a679..68c51d57aa7 100644
--- a/src/mongo/executor/network_interface_tl.h
+++ b/src/mongo/executor/network_interface_tl.h
@@ -31,9 +31,12 @@
 
 #include <deque>
 
+#include <boost/optional.hpp>
+
 #include "mongo/client/async_client.h"
 #include "mongo/db/service_context.h"
 #include "mongo/executor/connection_pool.h"
+#include "mongo/executor/connection_pool_tl.h"
 #include "mongo/executor/network_interface.h"
 #include "mongo/logv2/log_severity.h"
 #include "mongo/platform/mutex.h"
@@ -103,6 +106,33 @@ public:
                     Milliseconds timeout,
                     Status status) override;
 
+    /**
+     * NetworkInterfaceTL's implementation of a leased network-stream
+     * provided for manual use outside of the NITL's usual RPC API.
+     * When this type is destroyed, the destructor of the ConnectionHandle
+     * member will return the connection to this NetworkInterface's ConnectionPool.
+     */
+    class LeasedStream : public NetworkInterface::LeasedStream {
+    public:
+        AsyncDBClient* getClient() override;
+
+        LeasedStream(ConnectionPool::ConnectionHandle&& conn) : _conn{std::move(conn)} {}
+
+        // These pass-through indications of the health of the leased
+        // stream to the underlying ConnectionHandle
+        void indicateSuccess() override;
+        void indicateUsed() override;
+        void indicateFailure(Status) override;
+
+    private:
+        ConnectionPool::ConnectionHandle _conn;
+    };
+
+    SemiFuture<std::unique_ptr<NetworkInterface::LeasedStream>> leaseStream(
+        const HostAndPort& hostAndPort,
+        transport::ConnectSSLMode sslMode,
+        Milliseconds timeout) override;
+
 private:
     struct RequestState;
     struct RequestManager;
@@ -342,8 +372,10 @@ private:
     std::unique_ptr<transport::TransportLayer> _ownedTransportLayer;
     transport::ReactorHandle _reactor;
 
-    mutable Mutex _mutex =
-        MONGO_MAKE_LATCH(HierarchicalAcquisitionLevel(3), "NetworkInterfaceTL::_mutex");
+    // TODO SERVER-75830: This Mutex used to be at hierarcichal acquisition level 3. We temporary
+    // removed the level because it is sometimes acquired as part of task-scheduling when
+    // lower-level mutexes (like the ConnectionPool's) are held.
+    mutable Mutex _mutex = MONGO_MAKE_LATCH("NetworkInterfaceTL::_mutex");
     const ConnectionPool::Options _connPoolOpts;
     std::unique_ptr<NetworkConnectionHook> _onConnectHook;
     std::shared_ptr<ConnectionPool> _pool;