97     upper_inode: SpinLock<Option<Arc<dyn IndexNode>>>, // 读写层  field
112             upper_inode: SpinLock::new(upper),  in new()
156         let upper_inode = ROOT_INODE()  in make_overlayfs()  localVariable
162                 Some(upper_inode),  in make_overlayfs()
220         let mut upper_inode = self.upper_inode.lock();  in create_whiteout()  localVariable
221         if let Some(ref upper_inode) = *upper_inode {  in create_whiteout()
222             upper_inode.mknod(name, whiteout_mode, WHITEOUT_DEV)?;  in create_whiteout()
230             *upper_inode = Some(new_inode);  in create_whiteout()
243         let upper_inode = self.upper_inode.lock();  in has_whiteout()  localVariable
244         if let Some(ref upper_inode) = *upper_inode {  in has_whiteout()
245             if let Ok(inode) = upper_inode.find(name) {  in has_whiteout()
263         if let Some(ref upper_inode) = *self.upper_inode.lock() {  in read_at()
264             return upper_inode.read_at(offset, len, buf, data);  in read_at()
281         if (*self.upper_inode.lock()).is_none() {  in write_at()
284         if let Some(ref upper_inode) = *self.upper_inode.lock() {  in write_at()
285             return upper_inode.write_at(offset, len, buf, data);  in write_at()
296         if let Some(ref upper_inode) = *self.upper_inode.lock() {  in metadata()
297             return upper_inode.metadata();  in metadata()
312         let upper_inode = self.upper_inode.lock();  in list()  localVariable
313         if let Some(ref upper_inode) = *upper_inode {  in list()
314             let upper_entries = upper_inode.list()?;  in list()
334         if let Some(ref upper_inode) = *self.upper_inode.lock() {  in mkdir()
335             upper_inode.mkdir(name, mode)  in mkdir()
342         let upper_inode = self.upper_inode.lock();  in rmdir()  localVariable
343         if let Some(ref upper_inode) = *upper_inode {  in rmdir()
344             upper_inode.rmdir(name)?;  in rmdir()
359         let upper_inode = self.upper_inode.lock();  in unlink()  localVariable
360         if let Some(ref upper_inode) = *upper_inode {  in unlink()
361             upper_inode.unlink(name)?;  in unlink()
380         if let Some(ref upper_inode) = *self.upper_inode.lock() {  in link()
381             upper_inode.link(name, other)  in link()
393         if let Some(ref upper_inode) = *self.upper_inode.lock() {  in create()
394             upper_inode.create(name, file_type, mode)  in create()
401         let upper_inode = self.upper_inode.lock();  in find()  localVariable
402         if let Some(ref upper) = *upper_inode {  in find()
426         let upper_inode = self.upper_inode.lock();  in mknod()  localVariable
427         if let Some(ref inode) = *upper_inode {  in mknod()