Re: File System conversion -- ideas

Hugo Mills (hugo-lkml@carfax.org.uk)
Sun, 29 Jun 2003 23:25:40 +0100


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On Sun, Jun 29, 2003 at 05:54:58PM -0400, rmoser wrote:
> On 6/29/2003 at 10:37 PM Hugo Mills wrote:
> > Start with the easy bits: make a list of _every_ piece of metadata
> >that can be stored by an ext2 filesystem. Do the same for ReiserFS.
> >Work out how one maps to the other. Write a C/C++ struct to contain
> >that metadata. Work out how you're going to store your metadata nodes
> >on-disk. Those are the easy bits.
>=20
> Nerg. Heh that's gonna be hard to find. Need to get a book on filesyste=
ms.

Hardly difficult. I found what appears to be a pretty complete
35-page document on the structure of the FAT filesystem in about 10
seconds with Google. ext2 was a little tricker to find, but eventually
I got to the sourceforge project for e2fsprogs.

[snip]
> > Fix bugs, and repeat for ReiserFS.
> >
> > By this point, you will know how ext2 and Reiser really work. Then
> >you can start considering how to manage your metadata objects inside a
> >partly-converted filesystem. Work out how to do that, and implement it
>=20
> What? I'd rather structure the datasystem to handle it right off the bat.
> (I'm expecting to get flamed for this statement lol)

And quite rightly. Take small steps, moving towards your ultimate
goal. Don't try to get a perfect system working immediately -- you
_will_ fail (unless you're some previously unsung =FCbercoder, in which
case you'll merely find it insanely difficult :) ).

Hugo.

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