Linux filesystem Introduction

In general linux file system has 3 parts

• Superblock: it records the meta information for the linux filesystem. It contains the inode/iblock, amount, usage, free capacity and other file system information. The superblock information can be viewed by tune2fs
• Inode. Record the file attributes. Every file will have a inode
• Block: record the file content

Every file will use one inode and some blocks, the data will be allocated to the first block of the file, if it is over the block, then it will use the second block. Block can’t be shared between files

Inode contains the below information (most of information can be seen by stat file)

1.       permission

2.       ownership

3.       file size

4.       ctime, atime, mtime

5.       ACL

6.       file pointer

inode 3-layer index The inode use the 3 level table to contain the inodes mapping