Comment 20 for bug 34813

Ok, this is the problem:

Gedit opens a file, moves the original file to a backup file while keeping the file open, and finally deletes the backup file if you choose not to keep backups.
The rename method sets errno = ETXTBSY, so moving the original file fails.

I don't think moving/deleting open files on purpose is a good idea, although it works for most linux file systems. But its definitely a bad idea for network file systems like sshfs and cifs, which of course fails.