[lug] 'df' returning bad numbers

[Jeff Schroeder]

I just did a major housecleaning on my system, moving about 20GB of data 
to another hard drive.  Although I know the drive now has a ton of free 
space, when I use 'df' it reports a usage of 100%:

Filesystem           1k-blocks      Used Available Use% Mounted on
/dev/hda1              2016016    703012   1210592  37% /
/dev/hda5              4032092   1467944   2359324  39% /apps
/dev/hda3               497861     94114    378043  20% /var
none                     63320         0     63320   0% /dev/shm
/dev/md0              76920352  18676320  57462552  25% /data
/dev/hda6             69860376  68615112         0 100% /xdata

/xdata is the disk in question-- you can see the data I moved to /data 
takes up 18.7GB.  I'm positive there's actually at least that much 
space free on /xdata.

I've rebooted and even run fsck on the (unmounted) file system, but it 
continues to believe it's full.

Is there a command or procedure I should follow to "re-sync" the 
filesystem and fix this?  More importantly, if the disk "thinks" it's 
full, what's going to happen when I continue writing data to it?  I'm 
adding about 1GB of data every day from various backup scripts...

TIA,
Jeff