ext2 - ext3 - ext4
Posted Jun 15, 2006 11:26 UTC (Thu) by nix
In reply to: ext2 - ext3 - ext4
Parent article: Time for ext4?
This is an argument for calling it 'ext3'.
If the extents code were added in a copy of the filesystem, called ext4, then you could go to ext4+extents easily, but going back would be impossible unless extents were optional even in ext4 (which introduces to ext4 all the complexity problems which ruled out its being called ext3!)
If extents are optional, then you can remove extent blocks from files by mounting without extents (but *with an extent-capable fs*, so new ext3 or ext4 or whatever), then copying and renaming all files which have extents on them. It's fiddly, but doable.
If you introduce an ext4 with non-optional extents, then there's no filesystem which can read extents but prefers not to write them. Oops, *now* you can't go back.
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