For those of you folks out there who, like me, carry around an Ubuntu-based live CD/USB as a friendly and handy system recovery companion, you might be surprised and shocked (as I was) to discover that LVM partitions that some Fedora systems are apparently installed on are unsupported by stock Ubuntu live systems. Ie – you cannot mount these partitions or do anything with them except delete/format them.
Fortunately it turns out that there is a quick remedy – install that support. Make sure that you have internet access, then simply do:
sudo apt-get install lvm2
You should now be able to mount and read the partition.