Implementing ext4

[PavelChekov]

How would I implement the ext4 filesystem in my OS? The only detailed article on the wiki concerning ext is ext2.

Thanks

[Octocontrabass]

All the information you need should be here.

[PavelChekov]

Thanks!

[PavelChekov]

Where is the superblock located on the harddisk?

(I know this is probably a better question for a Linux forum, but I'll ask it here anyway.)

[Octocontrabass]

It starts at byte offset 1024 in the partition.

[PavelChekov]

Is there an all-in-one doc containing all the specifications of ext4?

Also, I cannot find documentation on XFS, JFS, BTRFS, UFS, or ZFS . . .

[Octocontrabass]

Is there an all-in-one doc containing all the specifications of ext4?

This is the closest you're going to get.

Also, I cannot find documentation on XFS, JFS, BTRFS, UFS, or ZFS . . .

You're not looking very hard.

[PavelChekov]

Allow me to be more specific: I cannot find any up-to-date documentation from the original site, and not from some unknown webpage on the corner of the web, which has a scan of it.

[Korona]

Few FSes have formal specs (though counterexamples such as FAT exist). For most FSes that are originally implemented for Linux, the source is the most reliable documentation.