[ext2resize] Re: [Ext2-devel] Re: [patch] ext2fs_allocate_group_table cleanup

[Theodore Ts'o <ty...@mi...>]

On Fri, Mar 17, 2006 at 10:19:44AM -0700, Andreas Dilger wrote:
> On Mar 17, 2006  10:21 -0500, Theodore Ts'o wrote:
> > I've been meaning to ask you.... now that I have online resizing
> > support integrated into resize2fs, is there any other features in
> > ext2resize that isn't in resize2fs?  (Aside from ext2prepare, of
> > course.)
> 
> What???  I didn't know that was done.  Since when did you do that?
> Excellent news.

Last night, around 1am.  :-)  

It's not yet checked into mercurial yet, but it's working.  I still
need to quickly update the man page and decide whether or not provide
a command-line compatible version of ext2online or just try to tell
users/scripts to recode to use resize2fs instead. 

> As for ext2prepare, that is really just resize2fs that doesn't extend
> the end of the filesystem, and creates/modifies the resize inode.  I
> believe that e2fsck already handles the resize inode, so combining the
> parts is all that's needed.

Not really.  You *can* do it using some somewhat obscure debugfs,
followed by running e2fsck -f and answering yes to a whole bunch of
scary questions, and in some cases it still might not work.  So we
still need to enhance either resize2fs or write some new program if we
want ext2prepare functionality.

One thing I have thought about doing is simply enhacing
/usr/src/linux/fs/ext3/resize.c to support metablock groups, and
automatically switching to use meta blockgroups once there are no more
reserved gdt blocks.  This means you no longer need ext2prepare, and
aside from some conservative stick-in-the-mud types running RHEL 3 or
other distro's with 2.4 kernels (heck, even Debian has finally gotten
off of 2.4), all modern Linux systems will support the metablock group
feature anyway.  This will allow us to do resizing without needing to
use ext2prepare, or needing to reserve blocks at all.  

						- Ted