Re: universal filesystem convertor

[Serguei Tzukanov]

Andrew Clausen wrote:
> Yep, nice idea :)  It will run into problems in low free space.
> (free space must be > largest file, right).

This can be solved by special copy, i.e. we get few last pages of the 
file from primary fs, truncate the file and write these pages at the end 
of destination file (if secondary fs does not support sparse files, we 
can write in reversed order :-).

> Also, your convertfs can also be used as a resizer, right?
Yes, you are right.
We can even collect many loop devices into one LVM device, repartition 
it another way than the real disk and create a totally different 
physical layout.


> I guess it's all rather slow, but nice none-the-less :)
> You might also be interested in Partition Surprise (google it!)
It's slow mostly because of journaling.
Hmm... Partition Surprise will need special handling of reiserfs because 
of its tail compression.

> Ralf Bächle told me he thought there might be problems with using
> loopback like this... I guess it's working ok?

Loopback works fine for me on 2.4.17.

Another thing is that implemented algorithm is somewhat buggy.
This is still proof-of-concept version.