Fix Windows disk usage metric measurement

This PR will fix issue kubernetes#81088. The current fs_windows utility reports
the whole file system usage instead of specific file path. This PR fix
this and walk the dir tree under the file path and collect the disk
usage.

Change-Id: I502ccf0af4bd07be69b61be043be616660499e4d

Author: jingxu97

pkg/volume/util/fs/BUILD

@@ -1,4 +1,4 @@
-load("@io_bazel_rules_go//go:def.bzl", "go_library")
+load("@io_bazel_rules_go//go:def.bzl", "go_library", "go_test")
 
 go_library(
     name = "go_default_library",
@@ -65,3 +65,15 @@ filegroup(
     tags = ["automanaged"],
     visibility = ["//visibility:public"],
 )
+
+go_test(
+    name = "go_default_test",
+    srcs = ["fs_windows_test.go"],
+    embed = [":go_default_library"],
+    deps = select({
+        "@io_bazel_rules_go//go/platform:windows": [
+            "//staging/src/k8s.io/apimachinery/pkg/api/resource:go_default_library",
+        ],
+        "//conditions:default": [],
+    }),
+)

pkg/volume/util/fs/fs_windows.go

@@ -20,6 +20,7 @@ package fs
 
 import (
 	"fmt"
+	"os"
 	"syscall"
 	"unsafe"
 
@@ -58,7 +59,12 @@ func FsInfo(path string) (int64, int64, int64, int64, int64, int64, error) {
 
 // DiskUsage gets disk usage of specified path.
 func DiskUsage(path string) (*resource.Quantity, error) {
-	_, _, usage, _, _, _, err := FsInfo(path)
+	info, err := os.Lstat(path)
+	if err != nil {
+		return nil, err
+	}
+
+	usage, err := diskUsage(path, info)
 	if err != nil {
 		return nil, err
 	}
@@ -75,3 +81,41 @@ func DiskUsage(path string) (*resource.Quantity, error) {
 func Find(path string) (int64, error) {
 	return 0, nil
 }
+
+func diskUsage(currPath string, info os.FileInfo) (int64, error) {
+	var size int64
+
+	if info.Mode()&os.ModeSymlink != 0 {
+		return size, nil
+	}
+
+	size += info.Size()
+
+	if !info.IsDir() {
+		return size, nil
+	}
+
+	dir, err := os.Open(currPath)
+	if err != nil {
+		return size, err
+	}
+	defer dir.Close()
+
+	files, err := dir.Readdir(-1)
+	if err != nil {
+		return size, err
+	}
+
+	for _, file := range files {
+		if file.IsDir() {
+			s, err := diskUsage(fmt.Sprintf("%s/%s", currPath, file.Name()), file)
+			if err != nil {
+				return size, err
+			}
+			size += s
+		} else {
+			size += file.Size()
+		}
+	}
+	return size, nil
+}

pkg/volume/util/fs/fs_windows_test.go

@@ -0,0 +1,81 @@
+/*
+Copyright 2019 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package fs
+
+import (
+	"fmt"
+	"io/ioutil"
+	"os"
+
+	"k8s.io/apimachinery/pkg/api/resource"
+	"testing"
+)
+
+func TestDiskUsage(t *testing.T) {
+
+	dir_1, err := ioutil.TempDir("", "dir_1")
+	if err != nil {
+		t.Fatalf("TestDiskUsage failed: %s", err.Error())
+	}
+	defer os.RemoveAll(dir_1)
+
+	tmpfile_1, err := ioutil.TempFile(dir_1, "test")
+	if _, err = tmpfile_1.WriteString("just for testing"); err != nil {
+		t.Fatalf("TestDiskUsage failed: %s", err.Error())
+	}
+	dir_2, err := ioutil.TempDir(dir_1, "dir_2")
+	if err != nil {
+		t.Fatalf("TestDiskUsage failed: %s", err.Error())
+	}
+	tmpfile_2, err := ioutil.TempFile(dir_2, "test")
+	if _, err = tmpfile_2.WriteString("just for testing"); err != nil {
+		t.Fatalf("TestDiskUsage failed: %s", err.Error())
+	}
+
+	dirInfo1, err := os.Lstat(dir_1)
+	if err != nil {
+		t.Fatalf("TestDiskUsage failed: %s", err.Error())
+	}
+	dirInfo2, err := os.Lstat(dir_2)
+	if err != nil {
+		t.Fatalf("TestDiskUsage failed: %s", err.Error())
+	}
+	file1 := dir_1 + "/" + "test"
+	file2 := dir_2 + "/" + "test"
+	fileInfo1, err := os.Lstat(file1)
+	if err != nil {
+		t.Fatalf("TestDiskUsage failed: %s", err.Error())
+	}
+	fileInfo2, err := os.Lstat(file2)
+	if err != nil {
+		t.Fatalf("TestDiskUsage failed: %s", err.Error())
+	}
+	total := dirInfo1.Size() + dirInfo2.Size() + fileInfo1.Size() + fileInfo2.Size()
+
+	size, err := DiskUsage(dir_1)
+	if err != nil {
+		t.Fatalf("TestDiskUsage failed: %s", err.Error())
+	}
+	used, err := resource.ParseQuantity(fmt.Sprintf("%d", total))
+	if err != nil {
+		t.Fatalf("TestDiskUsage failed: %s", err.Error())
+	}
+	if size.Cmp(used) != 1 {
+		t.Fatalf("TestDiskUsage failed: %s", err.Error())
+	}
+
+}