Comment 7 for bug 1176977

http://people.canonical.com/~ppisati/linux-image-3.5.0-31-highbank_3.5.0-31.52~549142a_armhf.deb

other than the patch attached in #6, this kernel contains two more patches that address the free space fragmentation we were seeing: this kernel completely solves the problem for me, please test it.