Ports-tree fetch: No space left on device

Hi,

I'm trying to update my ports tree with 'cvs -q up -Pd -A' and I'm
getting the following error:

> cannot create_adm_p /tmp/cvs-serv54231/textproc/cdiff
> No space left on device

From this I assume that there may not be enough space on /tmp but
based on the output of 'df -h' it should:

Filesystem Size Used Avail Capacity Mounted on
/dev/sd1a 986M 135M 801M 15% /
/dev/sd1l 295G 17.1G 263G 7% /home
/dev/sd1d 3.9G 2.0M 3.7G 1% /tmp
/dev/sd1f 29.1G 3.7G 23.9G 14% /usr
/dev/sd1g 986M 290M 647M 31% /usr/X11R6
/dev/sd1h 19.4G 8.4G 10.0G 46% /usr/local
/dev/sd1k 5.8G 2.0K 5.5G 1% /usr/obj
/dev/sd1j 2.9G 2.0K 2.8G 1% /usr/src
/dev/sd1e 19.1G 65.0M 18.1G 1% /var

Is this not enough? IIRC my ports-tree should not be outdated by
more than a week or two. I really only use CVS for ports by running
the above mentioned command everytime I'm working with ports.

Thanks.

Kind regards,
Johannes