diff --git a/pkg/kubelet/dockershim/checkpoint_store.go b/pkg/kubelet/dockershim/checkpoint_store.go index 0447d6623ff..be9994fb939 100644 --- a/pkg/kubelet/dockershim/checkpoint_store.go +++ b/pkg/kubelet/dockershim/checkpoint_store.go @@ -18,6 +18,7 @@ package dockershim import ( "fmt" + "io" "io/ioutil" "os" "path/filepath" @@ -64,6 +65,24 @@ func NewFileStore(path string) (CheckpointStore, error) { return &FileStore{path: path}, nil } +// writeFileAndSync is copied from ioutil.WriteFile, with the extra File.Sync +// at the end to ensure file is written on the disk. +func writeFileAndSync(filename string, data []byte, perm os.FileMode) error { + f, err := os.OpenFile(filename, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, perm) + if err != nil { + return err + } + n, err := f.Write(data) + if err == nil && n < len(data) { + err = io.ErrShortWrite + } + f.Sync() + if err1 := f.Close(); err == nil { + err = err1 + } + return err +} + func (fstore *FileStore) Write(key string, data []byte) error { if err := validateKey(key); err != nil { return err @@ -72,7 +91,7 @@ func (fstore *FileStore) Write(key string, data []byte) error { return err } tmpfile := filepath.Join(fstore.path, fmt.Sprintf("%s%s%s", tmpPrefix, key, tmpSuffix)) - if err := ioutil.WriteFile(tmpfile, data, 0644); err != nil { + if err := writeFileAndSync(tmpfile, data, 0644); err != nil { return err } return os.Rename(tmpfile, fstore.getCheckpointPath(key))