I have an hard disk totally dedicated to ktorrent: its size is 160Gb.
du reports 97 Gb of used space. Ktorrent already downloaded (and it's now seeding) a torrent of 54 Gb; 23 Gb are used for other stuff and the last 20 GB are of a torrent partially downloaded (50 gb total size)
Now, ktorrent (2.2.5 on Fedora 7) refuses to start the download claiming that there is no enough space left on disk.
In a similar setup on another pc, I have no problem: the only difference I noticed is that in the first case, the temporary files directory (with the symlinks to the files downloaded) resides on the same partition of the downloaded data while in the second case it is in my home folder under ~/.kde/share/apps/ktorrent.
Could this somehow confuse ktorrent about the amount of space available?

I'll answer myself...
I removed the torrent keeping - obviously - the data; then I changed the temporary folder location, moving it to /tmp (on another partition than the one used for the downloaded data).
Finally, I reloaded the torrent: after the data check, it restarted fine.
So, if the symlinks in the ktorrent cache pointing at the real data to be downloaded are on the same partition of the real data itself, this does confuse ktorrent. Or maybe this happens only when the cache and the data share the same directory.