INODE,METADATA,SUPERBLOCK

INODE


A data structure that stores the below information about a file


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• Size of file
• Device ID
• User ID of the file
• Group ID of the file
• The file mode information and access privileges for owner, group and others
• File protection flags
• The timestamps for file creation, modification etc
• link counter to determine the number of hard links
• Pointers to the blocks storing file’s contents

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Inode doesnot store the file name and it is stored seperately, greatest advantage is hardlink can be created for different file name sharing same inode.

Meta data
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Its data about a data. Suppose you own a vehicle there are registration and other details of the vehicle that is not the part of it. Metadata gives info like

• File name
• Owner
• Creation date

Location on storage medium

SUPER BLOCK

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Metadata describes the structure of the file system. Most common metadata structure are superblock, inode and directories.

• File system type
• Size
• Status
• Information about other metadata structures
• Free inodes and blocks

 dumpe2fs /dev/hda3 | grep -i superblock

Primary superblock at 0, Group descriptors at 1-1
Backup superblock at 32768, Group descriptors at 32769-32769
Backup superblock at 98304, Group descriptors at 98305-98305
Backup superblock at 163840, Group descriptors at 163841-163841
Backup superblock at 229376, Group descriptors at 229377-229377
Backup superblock at 294912, Group descriptors at 294913-294913

If superblock is corrupted, execute fsck in backup super block

Example

e2fsck -b 32768 /dev/hda1