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Layered File System Layered File System

Layered File System - PowerPoint Presentation

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Layered File System - PPT Presentation

Sunil Venkatesh CMSC601 Spring 2011 05022011 Introduction Linux OS Supports more than 30 filesystems VFS subsystem Data structures inode file vmareastruct dentry and superblock ID: 329226

bin file font lib file bin lib font dev test user layer t1m1 team level interface directory black white

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Presentation Transcript

Slide1

Layered File System

Sunil Venkatesh

CMSC-601, Spring 2011, 05-02-2011Slide2

Introduction

Linux OS

Supports more than 30 filesystems

VFS subsystemData structures – inode, file, vm_area_struct, dentry and super_block

User Application

VFS Layer

Filesystem

Sys-call interface

Conceptual (VFS interface)

Physical Media

User

KernelSlide3

Motivation

Challenges in administering a Linux server

Users, Groups and Others (RWX)

Maintaining softwareNew featuresDelegation of authoritySecurity through isolation (“chroot jail”)Benefits in a CloudData is secureEasier maintenance of web- servicesSlide4

Related Work

Hendricks et al., Method and apparatus for translucent file system, 1991

Works best when a team working on shared data

Shared and Private hierarchyErez Zadok and Ion Badulescu, A Stackable File System Interface For Linuxvnode – represents files, directories and devices.

wrapfs achieved through vnode interfaceErez

Zadok and Ion Badulescu and Alex Shender, Cryptfs: A Stackable Vnode Level Encryption File System, 1998. Slide5

Depicting Layers

System Layer

Active Kernels

2.6.18-128.el5

2.6.38.4

Inactive Kernels

2.6.39-rc5

Layer Contents:

vmlinuz

initrd

grub

Application Layer

Graphics

Toosl

OpenGL

Glib

DirectFB

Development Tools

gcc

Java

fortron

Office Tools

word

spreadsheet

User Layer

User Group 1

alpha

bravo

charlie

User Group 2

delta

echo

foxtrot

User Group 3

golf

hotel

These layers in-turn can contain

sublayers

like: dev, testSlide6

Layered Organization

prj1

prj2

. . . . . . .

prj3

temp

. . . . . . .

base

prj

N

test

dev

test

dev

test

dev

test

bin

. . . . . . .

home

mnt

usr

/

bash

mkdir

mount

netstat

ping

pwd

tracepath

traceroute

unmount

bin

lib

sbin

share

. . . . . . .

Legend:

White Font: Directory

Black Font: File

T1M1 – Team 1, Member 1

dev

lib

root

bin

. . . . . . .

home

mnt

usr

/

bash

mkdir

mount

netstat

ping

pwd

tracepath

traceroute

unmount

bin

lib

sbin

share

. . . . . . .

Legend:

White Font: Directory

Black Font: File

T1M1 – Team 1, Member 1

dev

lib

root

T1M1

T1M2

T1M3

T1MN

. . . . . . .

bin

. . . . . . .

home

mnt

usr

/

bash

mkdir

mount

netstat

ping

pwd

tracepath

traceroute

unmount

bin

lib

sbin

share

. . . . . . .

Legend:

White Font: Directory

Black Font: File

T1M1 – Team 1, Member 1

dev

lib

root

T2M1

T2M2

T2M3

T2MN

. . . . . . .

bin

. . . . . . .

home

mnt

usr

/

bash

mkdir

mount

netstat

ping

pwd

tracepath

traceroute

unmount

bin

lib

sbin

share

. . . . . . .

Legend:

White Font: Directory

Black Font: File

T1M1 – Team 1, Member 1

dev

lib

root

TNM1

T NM2

TNM3

TNMN

. . . . . . .

dev

Level 1

Level 2

Level 3Slide7

An Example of a Layer

bin

. . . . . . .

home

mnt

usr

/

bash

mkdir

mount

netstat

ping

pwd

tracepath

traceroute

unmount

bin

lib

sbin

share

. . . . . . .

Legend:

White Font: Directory

Black Font: File

T1M1 – Team 1, Member 1

dev

lib

root

T1M1

T1M2

T1M3

T1MN

. . . . . . .

Python (v2.3)

gcc (v3.4)

Test Code 1

Test Code 2

Test Code 1

Test Code 1

Level 2

Level 3Slide8

Implementation

User Application

VFS Layer

Filesystem

Sys-call interface

Conceptual (VFS interface)

Physical Media

User

Kernel

wrapfs

Components to be implemented

A pseudo-filesystem

wrapfs layer

Modification

dentry operationsSlide9

Future Work

Layered hierarchy representation

Provide means for delegation of authority

Eliminate need for a user and group permission in each fileSlide10

Questions/Suggestions