[Falkirk] Resize of BTRFS while mounted as /

[Robert McLay]

Hi Guys,

 I've recently managed to get my hands on an O2 Joggler photo frame which
 can run Linux.

 The USB pen which boots the Ubuntu distro has one BTRFS root partition
 which does not seem to re-size.  According to the documentation[1], I *should* (10p) be able to re-size the 4GB partition to use the remaining
 3GB by issuing a command such as:

 btrfs filesystem resize max /mnt or btrfsctl -r max /mnt

 Perhaps I am doing something wrong, but I had always assumed you need
 to unmount a file-system to re-size it.  Given the docs say /mnt and I
 want to re-size / do I need to use a different command...?

 PS: Expect a future talk on O2 Jogglers once I get to grips with it...

 Refs: [1] https://btrfs.wiki.kernel.org/index.php/FAQ#Resizing_partitions_.28shrink.2Fgrow.29

 Cheers,
 Rab