RFC: Btrfs snapshots feature for F13

[Chris Ball]

Hi David,

   > Shouldn't it say "next time volume is mounted" instead of "next
   > boot"?  We can always special case rootfs to say "next boot" of
   > course (since rootfs can't be unmounted until next boot).

Good point.  That's fine.

   > Also, what is the mechanism to configure this? Just a simple
   > command from btrfs-progs (best)? Or does it require surgery to
   > /etc/fstab and/or the initramfs (bad)?

Josef's been thinking about exactly that -- the current situation
requires you to add subvol=<snapshot-name> to the mount args, which
indeed would require you to change fstab (for non-rootfs) or to add a
rootflags= argument to the grub menu (for rootfs).  He's considering
changing the btrfs disk format to add a "default subvolume for this
fs" field that would lead us to a simple btrfsctl command for setting
that field instead.  I agree that his solution's what we'd like.

   > OK. We need to decide how all this is going to work - maybe some
   > of it will go into GIO and be part of an abstraction that also
   > works for other filesystems, maybe it will be a Nautilus-only
   > feature. I don't know yet, leaning towards the latter right now,
   > but I guess we'll find out.

Makes sense.

Thanks again.  I've updated the feature draft to include the
Palimpsest UI suggestion.

- Chris.
-- 
Chris Ball   <cjb at laptop.org>
One Laptop Per Child