Switch all calls to filepath.Walk to filepath.WalkDir

WalkDir should be faster the Walk, since we often do
not need to stat files.

[NO NEW TESTS NEEDED] Existing tests should find errors.

Signed-off-by: Daniel J Walsh <dwalsh@redhat.com>

pkg/util/utils.go

@@ -3,6 +3,7 @@ package util
 import (
 	"encoding/json"
 	"fmt"
+	"io/fs"
 	"math"
 	"os"
 	"os/user"
@@ -731,3 +732,20 @@ func LookupUser(name string) (*user.User, error) {
 	}
 	return user.Lookup(name)
 }
+
+// SizeOfPath determines the file usage of a given path. it was called volumeSize in v1
+// and now is made to be generic and take a path instead of a libpod volume
+func SizeOfPath(path string) (uint64, error) {
+	var size uint64
+	err := filepath.WalkDir(path, func(path string, d fs.DirEntry, err error) error {
+		if err == nil && !d.IsDir() {
+			info, err := d.Info()
+			if err != nil {
+				return err
+			}
+			size += uint64(info.Size())
+		}
+		return err
+	})
+	return size, err
+}