> > The only way xattrs are useful is that backup/restore software doesn't
quoted text
> > have to know about every filesystem with it's specific attributes and
> > every magic ioctl for setting them. Instead it can save/restore
> > filesystem-specific attributes without understanding what do they mean.
> > However there's no need why application should use them. And no
> > application does.
>
> If no application does, then why back them up? Why implement them in the
> first place?
>
> In other words - some apps obviously do want to use the. Sadly.

You can add more functionality to filesystem and use xattrs to control it.
For example:
- acls
- compress file
- encrypt file (copy user's password into task_struct and use it to
encrypt his files)
- preallocate file in 4MB contignuous chunks, becuase it needs real time
multimedia access
- sync/append-only/immutable
etc.
However there's no need why an application should care whether the file is
compressed, whether it has acls, or so. And applications don't.

And I think this is the only legitimate use for xattrs. Who else uses them
except samba? I don't see how reiser4's hybrids would help.

Mikulas