Comment 7 for bug 403109

I'll just add that at least as of the version of deja-dup 14.2-1squeeze1which is in Debian squeeze, the error message simply states that disk is full, leading one naturally to assume that the *backup* disk is full, not the disk that is being backed up. This is quite confusing, so besides doing the check beforehand, it would be great to figure out how to give useful error messages, since it's not possible to determine in advance whether there will really be room for a few gigabytes of temporary files.