Deprecate ListLocks and ClearLocks (#6233)

No locks are ever left in memory, we also
have a periodic interval of clearing stale locks
anyways. The lock instrumentation was not complete
and was seldom used.

Deprecate this for now and bring it back later if
it is really needed. This also in-turn seems to improve
performance slightly.

cmd/admin-rpc_test.go

@@ -99,31 +99,6 @@ func testAdminCmdRunnerReInitFormat(t *testing.T, client adminCmdRunner) {
 	}
 }
 
-func testAdminCmdRunnerListLocks(t *testing.T, client adminCmdRunner) {
-	tmpGlobalObjectAPI := globalObjectAPI
-	defer func() {
-		globalObjectAPI = tmpGlobalObjectAPI
-	}()
-
-	testCases := []struct {
-		objectAPI ObjectLayer
-		expectErr bool
-	}{
-		{&DummyObjectLayer{}, false},
-		{nil, true},
-	}
-
-	for i, testCase := range testCases {
-		globalObjectAPI = testCase.objectAPI
-		_, err := client.ListLocks("", "", time.Duration(0))
-		expectErr := (err != nil)
-
-		if expectErr != testCase.expectErr {
-			t.Fatalf("case %v: expected: %v, got: %v", i+1, testCase.expectErr, expectErr)
-		}
-	}
-}
-
 func testAdminCmdRunnerServerInfo(t *testing.T, client adminCmdRunner) {
 	tmpGlobalBootTime := globalBootTime
 	tmpGlobalObjectAPI := globalObjectAPI
@@ -323,16 +298,6 @@ func TestAdminRPCClientReInitFormat(t *testing.T) {
 	testAdminCmdRunnerReInitFormat(t, rpcClient)
 }
 
-func TestAdminRPCClientListLocks(t *testing.T) {
-	httpServer, rpcClient, prevGlobalServerConfig := newAdminRPCHTTPServerClient(t)
-	defer httpServer.Close()
-	defer func() {
-		globalServerConfig = prevGlobalServerConfig
-	}()
-
-	testAdminCmdRunnerListLocks(t, rpcClient)
-}
-
 func TestAdminRPCClientServerInfo(t *testing.T) {
 	httpServer, rpcClient, prevGlobalServerConfig := newAdminRPCHTTPServerClient(t)
 	defer httpServer.Close()