Robby Griffin wrote:
> On Aug 28, 2007, at 00:37, Brendon Costa wrote:
>  attaches the system source tree below the sys directory in the user's
>  home directory.  This allows individual users to make private changes to
>  the source, and build new kernels, without those changes becoming visible
>  to other users.

Thanks for that. It makes sense that for union mounting over CD's etc
you would want this.

> ... and that's the only way I've ever actually seen them used. This
> would not be possible if shadow directory perms were made to match the
> underlying fs, because the system source tree does not normally allow
> arbitrary users to write.
> 
> I guess you could use something like tar or mtree to create all the
> shadow directories up front before doing the union mount.
> 
Yep. I am currently doing something like that at the moment (Using
pax). It's just not as nice a solution as it would be if the union
mount had an option to preserve permissions from the lower file
system, but it works.

Thanks for the info.
Brendon.