func (fs *DeviceFs) trimUnused(todo int64, node *fuse.Inode) (done int64) {
for _, ch := range node.Children() {
if done > todo {
break
}
if fn, ok := ch.FsNode().(*classicNode); ok {
done += fn.trim()
} else if ch.IsDir() {
done += fs.trimUnused(todo-done, ch)
}
}
return
}
