Re: File System conversion -- ideas

Davide Libenzi
2003-06-29T20:08:11Z

On Sun, 29 Jun 2003 viro@parcelfarce.linux.theplanet.co.uk wrote:

> I think that I will believe it when I see the patchset implementing it.
> Provided that it will be convincing enough. Other than that... Not
> really. You will need code for each pair of filesystems, since
> convertor will need to know *both* layouts. No amount of handwaving
> is likely to work around that. And we have what, something between
> 10 and 20 local filesystems? Have fun...
>
> If you want your idea to be considered seriously - take reiserfs code,
> take ext3 code, copy both to userland and put together a conversion
> between them. Both ways. That, by definition, is easier than doing
> it in kernel - you have the same code available and none of the limitations/
> interaction with other stuff. When you have it working, well, time to
> see what extra PITA will come from making it coexist with other parts
> of kernel (and with much more poor runtime environment).
>
> AFAICS, it is _very_ hard to implement. Even outside of the kernel.
> If you can get it done - well, that might do a lot for having the
> idea considered seriously. "Might" since you need to do it in a way
> that would survive transplantation into the kernel _and_ would scale
> better that O((number of filesystem types)^2).

Maybe defining a "neutral" metadata export/import might help in limiting
such NFS^2 ...

- Davide