Ok, so I did an apt-get -u dist-upgrade, and it errors out with this:

dpkg: error processing 
/var/cache/apt/archives/linux-headers-3.2.0-56-generic-pae_3.2.0-56.86_i386.deb 
(--unpack):
  unable to create 
`/usr/src/linux-headers-3.2.0-56-generic-pae/include/config/pppoatm.h.dpkg-new' 
(while processing 
`./usr/src/linux-headers-3.2.0-56-generic-pae/include/config/pppoatm.h'): 
No space left on device

So yeah, it can't create that file because no space left on device.

Except there's plenty of space left on device:

   root at tiger:/# df -h /usr/src/
   Filesystem      Size  Used Avail Use% Mounted on
   /dev/sda5       4.0G  1.8G  2.0G  47% /usr

In fact there's no filesystem on this machine that's even close to full. 
Here are the 'real' filesystems:

   Filesystem      Size  Used Avail Use% Mounted on
   /dev/sda3       4.0G  1.2G  2.6G  32% /
   /dev/sda8       9.9G  151M  9.2G   2% /tmp
   /dev/sda1       504M   98M  382M  21% /boot
   /dev/sda7       4.0G  1.8G  2.0G  48% /home
   /dev/sda5       4.0G  1.8G  2.0G  47% /usr
   /dev/sda6       4.0G  455M  3.3G  12% /var
   /dev/sda9       2.0G   70M  1.9G   4% /usr/local

I can manually create the files it wants, too.

Anyone have any ideas?

--