When trying to write to the iPod from linux, you may get a read-only error, in particular if your iPod is formatted for Mac — that is, it’s HFS+, and you receive an error message about a failure to create a lockfile and read-only permissions, you’ll probably need to boot into a Mac and turn off journaling on your iPod.
Open the Disk Utility and turn of journaling on iPod.
To do this, connect your iPod to a Mac and type -
$ diskutil disableJournal /Volumes/iPod
Linux - Mac - Media