Golang sys.Syncfs函数代码示例

// sync syncs the pod data. By now it calls a syncfs on the filesystem
// containing the pod's directory.
func (p *pod) sync() error {
	cfd, err := p.Fd()
	if err != nil {
		return errwrap.Wrap(fmt.Errorf("error acquiring pod %v dir fd", p.uuid.String()), err)
	}
	if err := sys.Syncfs(cfd); err != nil {
		return errwrap.Wrap(fmt.Errorf("failed to sync pod %v data", p.uuid.String()), err)
	}
	return nil
}

// Write renders the ACI with the provided key in the treestore
// Write, to avoid having a rendered ACI with old stale files, requires that
// the destination directory doesn't exist (usually Remove should be called
// before Write)
func (ts *TreeStore) Write(key string, s *Store) error {
	treepath := filepath.Join(ts.path, key)
	fi, _ := os.Stat(treepath)
	if fi != nil {
		return fmt.Errorf("treestore: path %s already exists", treepath)
	}
	imageID, err := types.NewHash(key)
	if err != nil {
		return fmt.Errorf("treestore: cannot convert key to imageID: %v", err)
	}
	if err := os.MkdirAll(treepath, 0755); err != nil {
		return fmt.Errorf("treestore: cannot create treestore directory %s: %v", treepath, err)
	}
	err = aci.RenderACIWithImageID(*imageID, treepath, s)
	if err != nil {
		return fmt.Errorf("treestore: cannot render aci: %v", err)
	}
	hash, err := ts.Hash(key)
	if err != nil {
		return fmt.Errorf("treestore: cannot calculate tree hash: %v", err)
	}
	err = ioutil.WriteFile(filepath.Join(treepath, hashfilename), []byte(hash), 0644)
	if err != nil {
		return fmt.Errorf("treestore: cannot write hash file: %v", err)
	}
	// before creating the "rendered" flag file we need to ensure that all data is fsynced
	dfd, err := syscall.Open(treepath, syscall.O_RDONLY, 0)
	if err != nil {
		return err
	}
	defer syscall.Close(dfd)
	if err := sys.Syncfs(dfd); err != nil {
		return fmt.Errorf("treestore: failed to sync data: %v", err)
	}
	// Create rendered file
	f, err := os.Create(filepath.Join(treepath, renderedfilename))
	if err != nil {
		return fmt.Errorf("treestore: failed to write rendered file: %v", err)
	}
	f.Close()

	if err := syscall.Fsync(dfd); err != nil {
		return fmt.Errorf("treestore: failed to sync tree store directory: %v", err)
	}
	return nil
}

// Write renders the ACI with the provided key in the treestore. id references
// that specific tree store rendered image.
// Write, to avoid having a rendered ACI with old stale files, requires that
// the destination directory doesn't exist (usually Remove should be called
// before Write)
func (ts *TreeStore) Write(id string, key string, s *Store) (string, error) {
	treepath := ts.GetPath(id)
	fi, _ := os.Stat(treepath)
	if fi != nil {
		return "", fmt.Errorf("path %s already exists", treepath)
	}
	imageID, err := types.NewHash(key)
	if err != nil {
		return "", errwrap.Wrap(errors.New("cannot convert key to imageID"), err)
	}
	if err := os.MkdirAll(treepath, 0755); err != nil {
		return "", errwrap.Wrap(fmt.Errorf("cannot create treestore directory %s", treepath), err)
	}
	err = aci.RenderACIWithImageID(*imageID, treepath, s, uid.NewBlankUidRange())
	if err != nil {
		return "", errwrap.Wrap(errors.New("cannot render aci"), err)
	}
	hash, err := ts.Hash(id)
	if err != nil {
		return "", errwrap.Wrap(errors.New("cannot calculate tree hash"), err)
	}
	err = ioutil.WriteFile(filepath.Join(treepath, hashfilename), []byte(hash), 0644)
	if err != nil {
		return "", errwrap.Wrap(errors.New("cannot write hash file"), err)
	}
	// before creating the "rendered" flag file we need to ensure that all data is fsynced
	dfd, err := syscall.Open(treepath, syscall.O_RDONLY, 0)
	if err != nil {
		return "", err
	}
	defer syscall.Close(dfd)
	if err := sys.Syncfs(dfd); err != nil {
		return "", errwrap.Wrap(errors.New("failed to sync data"), err)
	}
	// Create rendered file
	f, err := os.Create(filepath.Join(treepath, renderedfilename))
	if err != nil {
		return "", errwrap.Wrap(errors.New("failed to write rendered file"), err)
	}
	f.Close()

	// Write the hash of the image that will use this tree store
	err = ioutil.WriteFile(filepath.Join(treepath, imagefilename), []byte(key), 0644)
	if err != nil {
		return "", errwrap.Wrap(errors.New("cannot write image file"), err)
	}

	if err := syscall.Fsync(dfd); err != nil {
		return "", errwrap.Wrap(errors.New("failed to sync tree store directory"), err)
	}

	treeSize, err := ts.Size(id)
	if err != nil {
		return "", err
	}

	if err := s.UpdateTreeStoreSize(key, treeSize); err != nil {
		return "", err
	}

	return string(hash), nil
}

// render renders the ACI with the provided key in the treestore. id references
// that specific tree store rendered image.
// render, to avoid having a rendered ACI with old stale files, requires that
// the destination directory doesn't exist (usually remove should be called
// before render)
func (ts *Store) render(id string, key string) (string, error) {
	treepath := ts.GetPath(id)
	fi, _ := os.Stat(treepath)
	if fi != nil {
		return "", fmt.Errorf("path %s already exists", treepath)
	}
	imageID, err := types.NewHash(key)
	if err != nil {
		return "", errwrap.Wrap(errors.New("cannot convert key to imageID"), err)
	}
	if err := os.MkdirAll(treepath, 0755); err != nil {
		return "", errwrap.Wrap(fmt.Errorf("cannot create treestore directory %s", treepath), err)
	}
	err = aci.RenderACIWithImageID(*imageID, treepath, ts.store, user.NewBlankUidRange())
	if err != nil {
		return "", errwrap.Wrap(errors.New("cannot render aci"), err)
	}
	hash, err := ts.Hash(id)
	if err != nil {
		return "", errwrap.Wrap(errors.New("cannot calculate tree hash"), err)
	}
	err = ioutil.WriteFile(filepath.Join(treepath, hashfilename), []byte(hash), 0644)
	if err != nil {
		return "", errwrap.Wrap(errors.New("cannot write hash file"), err)
	}
	// before creating the "rendered" flag file we need to ensure that all data is fsynced
	dfd, err := syscall.Open(treepath, syscall.O_RDONLY, 0)
	if err != nil {
		return "", err
	}
	defer syscall.Close(dfd)
	if err := sys.Syncfs(dfd); err != nil {
		return "", errwrap.Wrap(errors.New("failed to sync data"), err)
	}
	// Create rendered file
	f, err := os.Create(filepath.Join(treepath, renderedfilename))
	if err != nil {
		return "", errwrap.Wrap(errors.New("failed to write rendered file"), err)
	}
	f.Close()

	// Write the hash of the image that will use this tree store
	err = ioutil.WriteFile(filepath.Join(treepath, imagefilename), []byte(key), 0644)
	if err != nil {
		return "", errwrap.Wrap(errors.New("cannot write image file"), err)
	}

	if err := syscall.Fsync(dfd); err != nil {
		return "", errwrap.Wrap(errors.New("failed to sync tree store directory"), err)
	}

	// TODO(sgotti) this is wrong for various reasons:
	// * Doesn't consider that can there can be multiple treestore per ACI
	// (and fixing this adding/subtracting sizes is bad since cannot be
	// atomic and could bring to duplicated/missing subtractions causing
	// wrong sizes)
	// * ImageStore and TreeStore are decoupled (TreeStore should just use acirenderer.ACIRegistry interface)
	treeSize, err := ts.Size(id)
	if err != nil {
		return "", err
	}

	if err := ts.store.UpdateTreeStoreSize(key, treeSize); err != nil {
		return "", err
	}

	return string(hash), nil
}