Recover deleted files on LVM volume

[Ben Finney <bignose@debian.org>]

Howdy all,

How can I recover files deleted on a ext4 volume, in a logical (LVM)
volume?

I accidentally deleted a tree of directories and files, after completing
a move of those files from elsewhere :-(

In the past I have successfully used ‘testdisk’ to discover and recover
deleted files. However when I try now, the tool apparently gets confused
that there's no partition table.

The “Advanced” menu item normally leads to a filesystem browser of
deleted files. On this (still quite happily working) LVM volume though,
‘testdisk’ complains that it can't find any partitions.

Should I be using ‘testdisk’ in a different way because this is an LVM
logical volume? Should I be using some other tool to recover a tree of
deleted files?

-- 
 \        “The right to search for truth implies also a duty; one must |
  `\      not conceal any part of what one has recognized to be true.” |
_o__)                                                 —Albert Einstein |
Ben Finney