[Freedombox-pkg-team] Bug#876514: plinth: snapshot info page should show space used per snapshot

[Petter Reinholdtsen]

Package: plinth
Version: 0.14.0+ds-1

I've experienced a problem with my freedombox.  It will hang when there
is no more room on its btrfs file system, and the snapshots will
quickliy fill up the disk to a point where it is impossible to do
anything.  I got a 20GiB virtual disk on my freedombox, and the files on
/ occupy around 3.7 GiB of this.  The disk filled up completely with
snapshots. :(

So I have started to remove old snapshots, but it is more work than I
would like, as it is impossible to see from the Plinth snapshot web page
how much space the snapshots are actually using.  Please extend the info
page to show snapshot usage.  A way to do this is documented in
<URL: https://raw.githubusercontent.com/agronick/btrfs-size/master/btrfs-size.sh >.
For it to work, 'btrfs quota enable /' must be pat of the default setup
on Freedombox.  I am not sure it is enabled by default.

It would be even greater if I did not have to do this manual removal of
snapshots, for example by changing snapper to be able to remove old
snapshots in a way that ensure snapshots only take up a fraction of the
available disk space (say 80%).

-- 
Happy hacking
Petter Reinholdtsen