.. SPDX-License-Identifier: GPL-2.0
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Overview of the Linux Virtual File System
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Original author: Richard Gooch <rgooch@atnf.csiro.au>
- Copyright (C) 1999 Richard Gooch
- Copyright (C) 2005 Pekka Enberg
Introduction
============
The Virtual File System (also known as the Virtual Filesystem Switch) is
the software layer in the kernel that provides the filesystem interface
to userspace programs. It also provides an abstraction within the
kernel which allows different filesystem implementations to coexist.
VFS system calls open(2), stat(2), read(2), write(2), chmod(2) and so on
are called from a process context. Filesystem locking is described in
the document Documentation/filesystems/locking.rst.
Directory Entry Cache (dcache)
------------------------------
The VFS implements the open(2), stat(2), chmod(2), and similar system
calls. The pathname argument that is passed to them is used by the VFS
to search through the directory entry cache (also known as the dentry
cache or dcache). This provides a very fast look-up mechanism
