Re: [PATCH] 2/11 Ext2/3 Updates: Extended attributes, ACL, etc.

[Alexander Viro]

On Thu, 31 Oct 2002, Theodore Ts'o wrote:

> I'm not sure ext2meta will be sufficient.  It's not just a matter of
> modifying the on-disk metadata, as would be needed for defrag, but I
> would also need to modify some of the in-core data structions in the
> ext2/3 filesystem data structures.  For example, when you resize the
> filesystem, you need to increase the number of group descriptors,
> which means you need to kmalloc, copy, and then kfree sbi->group_desc
> out from under the mounted filesystem.
> 
> No doubt ext2meta could be modified so it could "reach out and touch"
> internal ext2/3 fileststem data structures in core.  But the locking
> issues involved get really messy.

For all practical purposes, ext2meta is part of ext2 - same driver,
two filesystem types.  Locking isn't that scary, BTW - I'd looked
into that some time ago and it looked feasible.