Each actual file system is separated from the operating system and system services, and they communicate with each other through an interface layer: virtual file system or VFS. VFS enables Linux to support multiple different file systems, and each file system represents a common interface of VFS. Because the software transforms all the details of the Linux file system, the other parts of the Linux kernel and the programs running in the system will see a unified file system. Linux's virtual file system allows users to transparently install many different file systems at the same time.
In Linux file system, /proc file system, as a special type, only exists in memory and does not occupy external storage space. It provides an interface for accessing system kernel data in the form of a file system. /proc file system is a pseudo file system. Users and applications can obtain system information through /proc and change some parameters of the kernel.
In Linux file system, EXT2 file system, virtual file system and /proc file system are three representative file systems. This paper attempts to study the mechanism of Linux file system by analyzing them. And on the basis of analyzing these three file systems, we understand and study the operation of Linux file system (this paper chooses opening and closing two operations to study). The second part will introduce EXT2 file system; The third part discusses the characteristics of virtual file system; The fourth part briefly introduces the /proc file system; Finally, the implementation of two specific file system operations is introduced.