I just wrote a chunk of stuff no my blog, refering to one the posts here. Hope some folks find something useful. I've really found zero Linux specific problems on the Sansa Clip+. On the contrary the flexibility and ease makes it very easy to automate stuff. All the tools I use (fdisk, df, rsync, mlabel, id3v2, rhythmbox etc ) were either on my Ubuntu system already or available in the standard repos just a "aptitude install" away.
blogpost :
Linux howto : Sansa Clip+ a brilliant little flac/ogg/mp3 player
Here's a snippet....
3. How to recover if only part of the space is available on a Sansa Clip+
This happened to me after I upgraded the firmware and only about half the 8GB space was usable, said “df -h” and when I filled up, prematurely to my mind, the MUSIC folder with 4.5GBs of flac, ogg and mp3s. Something was clearly wrong since the filesytem seemed bare otherwise, empty dirs and reasonably sized system files. I checked to see the partition state, whilst mounted (read-only operation so ok), with “fdisk -l /dev/sdc”. This showed wierd unmounted sub-partitions (sdc1, sdc2, etc) with improper cylinder boundaries. So I checked up online and found that if I could get into the OS as usual, there was an internal “format” function in “System Settings” which formatted the drive (not the OS, that was ok) and corrected the size problem. Now “df -h” showed 7.9GB of free space as expected