Re: VFS 64-bit clean

Theodore Y. Ts'o (tytso@MIT.EDU)
Tue, 24 Feb 1998 23:19:09 -0500

Date: Tue, 24 Feb 1998 16:25:01 -0500 (EST)
From: Rob Hagopian <>

What, you can't backup and restore when ext4fs comes out with b-tree
directories and no more triple/quad indirect inodes? Filesystems also
have to be rock solid. ext2fs is pretty darn close, and doing a
clean extension to 64-bit wouldn't jeopradize that. As soon as you
start tossing in things like b-trees you increase the amount of
testing that needs to be done dramaticly, and that takes lots of
time. People need this now.

B-tree directories can be cleanly added to ext2. The hard part is
writing code that implements B-trees cleanly in the kernel (including
handling the case of B-tree splits in the SMP case). Once we have this
code written, we then simply make actual *use* of B-tree directories to
be optional, and that makes for an easy transition path.

I know how to handle the integration and backwards compatibility issues;
and honestly, they're not hard. Handling the B-tree code cleanly and
robustly is really the hard part of the problem.

- Ted

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