Re: [Utopia] Re: [patch] improved hal support for gnome-vfs

[Kay Sievers <kay sievers vrfy org>]

On Fri, Jul 01, 2005 at 11:01:46PM -0400, David Zeuthen wrote:
> On Thu, 2005-06-30 at 11:16 +0200, Alexander Larsson wrote:

> > It would be nice to eventually change this and support changes to
> > drives/volumes, as that would allow nice things like renaming of
> > connected servers. However, right now there is no such support.
> 
> Right, this would be nice. I know Kay Sievers wants to add code to
> volume_id (the library used by hal to detect file systems types, labels
> and UUID's) so we can write new labels. This would enable us to also
> rename media.

Sure, this will happen as soon as the udev infrastructure for this is
set. I'm currently move all the device persistent data into the udev
database to provide persistent symlink-names in /dev pointing to the
device node. This is needed for the low-level stuff like servers and
boxes with thousends of disks attached. It will be something like a
"poor mans low-level product-database". :)

If I have this running, I will get to label-writing support for
volume_id, so beeing prepared with the desktop ui stuff to be able to
invoke (whatever method it will be) something that changes the label is
definitely nice to have.

I'm still not sure what things we need to work around, but at least for
some filesystems, we can do label changing only safely while the
volume is unmounted (*). So a label-rename must initiate:
  umount -> rename -> mount
If this is not feasible, for some user experience reason or whatever,
let us know, cause we may need to prepare kernel changes then...

Thanks,
Kay


* FAT stores the label in the root directory as a normal filename but
  with a special attribute. It can be at any place in the filename-list of
  the root directory. We have no way to make sure that the kernel isn't
  changing the same structures at the same time cause of disk activity.

  ext3/reiser should be safe, but we still face the problem, that the
  mount-point may be named after the label and should change then too.
  (Btw: I'm able to crash MacOS X, while setting FAT labels and keeping
   files opened on the mounted device :))