Strang df -h output

[Harry Putnam]

My setup:
*--
Software:
Linux kernel 2.6.7-1.517 Architecture i686
Fedora Core release 2.90 (FC3 Test 1)
Hardware:
model name	: Intel(R) Pentium(R) 4 CPU 2.00GHz
cpu MHz		: 1994.800
*--

I'm seeing output from `df -h' that I've never seen before.  Not sure
when it started but I think it could only be a matter of days at most
since I last ran `df -h' for some reason.

Filesystem            Size  Used Avail Use% Mounted on
[...]
/dev/hda5              36G   20G   15G  58% /anex
none                  253M     0  253M   0% /dev/shm
/dev/hdb9             7.6G  448M  6.7G   7% /home
/dev/hda2              15G  -64Z   15G 101% /mnt/pack
/dev/hdb11             12G  4.6G  6.0G  44% /news
[...] some unnecessary stuff snipped

Note the strange output for /dev/hda2 (/mnt/pack)
What on earth does that mean?

That partition actually has 2.6 gigs of data on it by `du' reconning:

du -sh /mnt/pack
2.6G    /mnt/pack

Its not a symlink or something:

  ls -ld /mnt/pack
drwxr-xr-x  10 reader reader 4096 Sep  4 10:54 /mnt/pack

So what is that output telling me?