[Fedora-livecd-list] [PATCH] overlay/persistence second pass - for developer reference only

[Douglas McClendon]

Attached is a revision to the persistence implementation that I posted a 
couple weeks ago.  This is mainly for Jeremy, Tim, and anyone else who 
is interested in working on this, or something similar.  I.e. at the 
very least, it is worth a read to look at the issues I've dealt with, 
and the several that are in comments as TODO.

It may well be that a simpler persistence implementation that involves 
just extracting tarballs from usbsticks into the normal ram overlay, may 
be useful instead of (or even in addition to) this kind of 
implementation.  (or perhaps some implementation of unionfs will make it 
into fedora eventually?)

The main points of note, since the first post are-

- all sorts of bugs fixed

- I moved the overlay storage filesystem to be visible as /mnt/overlayfs 
always.  This solves some aspects of the current problem of not easily 
being able to see how much writable space you really have available on 
the rootfs.  (the real answer is a combination of the device mapper 
overlay file AND the filesystem it resides on).

- I've included modified /etc/rc.d/init.d/halt and functions, to handle 
getting things cleanly shutdown (which is VERY important)

- ntfs is somewhat present, but not really working.  I have tested with 
vfat and ext3.  Note that ext3 is a PITA when not cleanly unmounted- see 
TODOs.

- rudimentary testing of the choice selection when multiple possible 
overlay images are detected suggests it works.

- the patch format merely reflects my educational process with git, and 
not that I suggest that code this immature is anywhere near ready for 
merging.  (i.e. inclusion of halt&functions and the origs I based them 
off of.  Refer to list archives for documentation on how to use 
addidir/addsdir if needed)

As always, comments/criticisms/suggestions are more than welcome.

peace...

-dmc