Tor Browser Bundle 3.5 holds open files (gvfsd-metadata)
gvfsd-met 16712 user mem REG 254,0 32768 1320143 /media/usb/tor-browser_en-US/.local/share/gvfs-metadata/uuid-306b4a6d-65c2-4d17-8696-97cca175bf5d-ffd15c89.log
These file handles persist after closing the browser and trying to eject the removal media causing errors on dismounting because a file is still held open by a process. I think this obviously needs to be fixed as it prevents tbb being "portable" in a sense.
Another related bug is https://trac.torproject.org/projects/tor/ticket/8707 described this issue as a privacy leak when it was being stored in the $HOME directory of users now that it is stored in tors directory it presents a new problem. I had commented on the previous bug about this but decided to move it to a new bug so it could get some attention and it's not exactly the same issue.