Re: restrictions for pattitions with ext2 file system

[Andrew Clausen]

On Thu, Aug 28, 2003 at 02:29:47PM +0600, Dimitry N. Naldaev wrote:
> > > What reason for the restriction ???
> >
> > It is rather difficult to design an algorithm to safely move the start
> > of a partition.  Such an algorithm was designed for FAT, but not ext2.
> >
> > Are you interested in the details?
> Yes... may be I can help... but I nothing know about internals ext2

Well, firstly, I think libparted should use libe2fs, which is
distributed with e2fsprogs.  It would be a lot less work to maintain ;)

Anyway, the main problem is that when you move the start, all
block numbers and inode numbers change, since they are numbered
relative to the start.  So, if you want to resize a file system
safely (i.e. so that it will survive even if the computer is switched
off while Parted is resizing)... then you need to be clever.

You need to make sure that whenever you write data, you aren't
damaging anything.  One way to guarantee this is to always write to
free space.  (The FAT resizer follows this strategy).

Make sense?

Cheers,
Andrew