Where is the inode number stored?

Question

I know that the filename is stored in directories and not in inode. Kindly tell me where the inode number of a file is stored? Is it stored in the directory file?

Solution 1

Yes, directory entries contain the filenames and their inodes.

Solution 2

Inode Structure image is provided below:

See from the above image. The contents of directory contains inode numbers. Each inode is the index to the inode table. The inode table is stored in the logic disk block. Each entry of inode table stores some file attributes, such as file size, permission, ownership, disk block address, time of last modification etc.

Both directories and ordinary (non-directory) files are files. This definition could be found on Chapter 4, "Modern Operating system", Prof. Andrew S. Tanenbaum.

Further information on inodes can be found here: http://140.120.7.20/LinuxKernel/LinuxKernel/node17.html

Comments

[LinuxPenseur]

Thanks jlliagre. So when I give ls -il, the inode numbers are listed from the directory file right?

[jlliagre]

Indeed, that's where they live.

[LinuxPenseur]

Thanks, Only when i give ls -l can i see the inode number. Since directory is also a file, is there any way to see the contents of directory which will list the inode numbers also

[jlliagre]

Your statement "a directory is also a file" is dubious. A directory is a directory, not a regular file. Depending on the operation system and the filesystem used, you might or might not be able to see the raw content of the directory. You can try "od -c directory".

[LinuxPenseur]

@jlliagre, I am sorry, but i will have to disagree with you on your comment on ""a directory is also a file" is dubious". As far as my knowledge goes Directories: files that are lists of other files. So i guess Directory is also a file

[jlliagre]

Directories are indeed files in the sense they appear in the filesystem tree but they aren't regular files. Just like devices, symlinks, named pipes, sockets and other exotic entries aren't regular files.

[user9517]

ls -i lists a directory's contents and inode numbers

[Janne Pikkarainen]

"In Linux, Inodes will be created when we create the filesystem itself." - that depends on the filesystem. The traditional ext[234] filesystems do have fixed inode table, but for example ReiserFS and XFS has dynamic inodes.

[Andrew B]

Can you switch those links out with ones from a more permanent website? (i.e. something with a DNS entry) I was going to edit the image into your answer, but we try to avoid links that are likely to break within the year.

[henry]

@AndrewB I don't find a new link with a DNS entry for this web. Sorry for that. Thanks for adding the picture. :-)