Module inode 

Arc<Inode> -> OSInodeInner: In order to open files concurrently we need to wrap Inode into Arc,but Mutex in Inode prevents file systems from being accessed simultaneously

UPSafeCell<OSInodeInner> -> OSInode: for static ROOT_INODE,we need to wrap OSInodeInner into UPSafeCell

Structs

OSInode

A wrapper around a filesystem inode to implement File trait atop

OSInodeInner

The OS inode inner in ‘UPSafeCell’

OpenFlags

Open file flags

ROOT_INODE

Functions

list_apps

List all files in the filesystems

open_file

Open file with flags