94     fn open(&self, _data: &mut FilePrivateData) -> Result<(), i32> {  in open()  argument
96         return Err(-(ENOTSUP as i32));  in open()
103     fn close(&self, _data: &mut FilePrivateData) -> Result<(), i32> {  in close()  argument
105         return Err(-(ENOTSUP as i32));  in close()
123     ) -> Result<usize, i32>;  in read_at()  argument
140     ) -> Result<usize, i32>;  in write_at()  argument
145     fn poll(&self) -> Result<PollStatus, i32>;  in poll()  argument
151     fn metadata(&self) -> Result<Metadata, i32> {  in metadata()  argument
153         return Err(-(ENOTSUP as i32));  in metadata()
160     fn set_metadata(&self, _metadata: &Metadata) -> Result<(), i32> {  in set_metadata()  argument
162         return Err(-(ENOTSUP as i32));  in set_metadata()
169     fn resize(&self, _len: usize) -> Result<(), i32> {  in resize()  argument
171         return Err(-(ENOTSUP as i32));  in resize()
187     ) -> Result<Arc<dyn IndexNode>, i32> {  in create()  argument
207     ) -> Result<Arc<dyn IndexNode>, i32> {  in create_with_data()  argument
209         return Err(-(ENOTSUP as i32));  in create_with_data()
219     fn link(&self, _name: &str, _other: &Arc<dyn IndexNode>) -> Result<(), i32> {  in link()  argument
221         return Err(-(ENOTSUP as i32));  in link()
230     fn unlink(&self, _name: &str) -> Result<(), i32> {  in unlink()  argument
232         return Err(-(ENOTSUP as i32));  in unlink()
241     fn rmdir(&self, _name: &str) ->Result<(), i32>{  in rmdir()  argument
242         return Err(-(ENOTSUP as i32));  in rmdir()
260     ) -> Result<(), i32> {  in move_()  argument
262         return Err(-(ENOTSUP as i32));  in move_()
271     fn find(&self, _name: &str) -> Result<Arc<dyn IndexNode>, i32> {  in find()  argument
273         return Err(-(ENOTSUP as i32));  in find()
282     fn get_entry_name(&self, _ino: InodeId) -> Result<String, i32> {  in get_entry_name()  argument
284         return Err(-(ENOTSUP as i32));  in get_entry_name()
293     fn get_entry_name_and_metadata(&self, ino: InodeId) -> Result<(String, Metadata), i32> {  in get_entry_name_and_metadata()  argument
307     fn ioctl(&self, _cmd: u32, _data: usize) -> Result<usize, i32> {  in ioctl()  argument
309         return Err(-(ENOTSUP as i32));  in ioctl()
320     fn list(&self) -> Result<Vec<String>, i32>;  in list()  argument
324     fn mount(&self, _fs: Arc<dyn FileSystem>) -> Result<Arc<MountFS>, i32> {  in mount()  argument
325         return Err(-(ENOTSUP as i32));  in mount()
331     fn truncate(&self, _len: usize) -> Result<(), i32> {  in truncate()  argument
332         return Err(-(ENOTSUP as i32));  in truncate()
349     pub fn lookup(&self, path: &str) -> Result<Arc<dyn IndexNode>, i32> {  in lookup()  argument
364     ) -> Result<Arc<dyn IndexNode>, i32> {  in lookup_follow_symlink()  argument
366             return Err(-(ENOTDIR as i32));  in lookup_follow_symlink()
383                 return Err(-(ENOTDIR as i32));  in lookup_follow_symlink()
417                     ::core::str::from_utf8(&content[..len]).map_err(|_| -(ENOTDIR as i32))?,  in lookup_follow_symlink()