Fix lint warning

Signed-off-by: Lei Jitang <leijitang@huawei.com>

image/change.go

@@ -58,16 +58,6 @@ func (c changesByPath) Less(i, j int) bool { return c[i].Path < c[j].Path }
 func (c changesByPath) Len() int           { return len(c) }
 func (c changesByPath) Swap(i, j int)      { c[j], c[i] = c[i], c[j] }
 
-// Gnu tar and the go tar writer don't have sub-second mtime
-// precision, which is problematic when we apply changes via tar
-// files, we handle this by comparing for exact times, *or* same
-// second count and either a or b having exactly 0 nanoseconds
-func sameFsTime(a, b time.Time) bool {
-	return a == b ||
-		(a.Unix() == b.Unix() &&
-			(a.Nanosecond() == 0 || b.Nanosecond() == 0))
-}
-
 func sameFsTimeSpec(a, b syscall.Timespec) bool {
 	return a.Sec == b.Sec &&
 		(a.Nsec == b.Nsec || a.Nsec == 0 || b.Nsec == 0)
@@ -218,7 +208,12 @@ func ChangesDirs(newDir, oldDir string) ([]Change, error) {
 		if err != nil {
 			return nil, err
 		}
-		defer os.Remove(emptyDir)
+		defer func() {
+			err := os.Remove(emptyDir)
+			if err != nil {
+				logrus.Debugf("failed to remove tmp dir: %v", err)
+			}
+		}()
 		oldDir = emptyDir
 	}
 	oldRoot, newRoot, err := collectFileInfoForChanges(oldDir, newDir)

image/change_unix.go

@@ -99,7 +99,7 @@ func walkchunk(path string, fi os.FileInfo, dir string, root *FileInfo) error {
 
 // Walk a subtree rooted at the same path in both trees being iterated. For
 // example, /oci/overlay/1234/a/b/c/d and /oci/overlay/8888/a/b/c/d
-func (w *filewalker) walk(path string, i1, i2 os.FileInfo) (err error) {
+func (w *filewalker) walk(path string, i1, i2 os.FileInfo) (retErr error) {
 	// Register these nodes with the return trees, unless we're still at the
 	// (already-created) roots:
 	if path != "/" {
@@ -315,11 +315,3 @@ func statDifferent(oldStat *utils.StatT, newStat *utils.StatT) bool {
 func (info *FileInfo) isDir() bool {
 	return info.parent == nil || info.stat.Mode()&syscall.S_IFDIR != 0
 }
-
-func getIno(fi os.FileInfo) uint64 {
-	return uint64(fi.Sys().(*syscall.Stat_t).Ino)
-}
-
-func hasHardlinks(fi os.FileInfo) bool {
-	return fi.Sys().(*syscall.Stat_t).Nlink > 1
-}

image/layer.go

@@ -21,6 +21,7 @@ import (
 	"path/filepath"
 )
 
+// CreateLayer create layer from filesystem changeset
 func CreateLayer(child, parent, dest string) error {
 	arch, err := Diff(child, parent)
 	if err != nil {