VFS: busy inodes on changed media or resized disk sr0

(Ubuntu 9.10 Karmic) If you get a lot of error messages like this:

Feb 7 14:38:58 theta kernel: [564762.288036] VFS: busy inodes on changed media or resized disk sr0
Feb 7 14:38:58 theta kernel: [564762.297408] VFS: busy inodes on changed media or resized disk sr0
Feb 7 14:38:59 theta kernel: [564763.286910] VFS: busy inodes on changed media or resized disk sr0
Feb 7 14:39:00 theta kernel: [564764.288880] VFS: busy inodes on changed media or resized disk sr0
Feb 7 14:39:00 theta kernel: [564764.298198] VFS: busy inodes on changed media or resized disk sr0
Feb 7 14:39:01 theta kernel: [564765.288943] VFS: busy inodes on changed media or resized disk sr0
Feb 7 14:39:02 theta kernel: [564766.287691] VFS: busy inodes on changed media or resized disk sr0
Feb 7 14:39:02 theta kernel: [564766.297007] VFS: busy inodes on changed media or resized disk sr0
Feb 7 14:39:03 theta kernel: [564767.339877] VFS: busy inodes on changed media or resized disk sr0
Feb 7 14:39:04 theta kernel: [564768.288076] VFS: busy inodes on changed media or resized disk sr0
Feb 7 14:39:04 theta kernel: [564768.297457] VFS: busy inodes on changed media or resized disk sr0
Feb 7 14:39:05 theta kernel: [564769.288688] VFS: busy inodes on changed media or resized disk sr0
Feb 7 14:39:06 theta kernel: [564770.292023] VFS: busy inodes on changed media or resized disk sr0
Feb 7 14:39:06 theta kernel: [564770.301389] VFS: busy inodes on changed media or resized disk sr0
Feb 7 14:39:07 theta kernel: [564771.316633] VFS: busy inodes on changed media or resized disk sr0
Feb 7 14:39:08 theta kernel: [564772.287440] VFS: busy inodes on changed media or resized disk sr0
Feb 7 14:39:08 theta kernel: [564772.296807] VFS: busy inodes on changed media or resized disk sr0
Feb 7 14:39:09 theta kernel: [564773.288408] VFS: busy inodes on changed media or resized disk sr0
Feb 7 14:39:10 theta kernel: [564774.288406] VFS: busy inodes on changed media or resized disk sr0
Feb 7 14:39:10 theta kernel: [564774.297774] VFS: busy inodes on changed media or resized disk sr0
Feb 7 14:39:11 theta kernel: [564775.286283] VFS: busy inodes on changed media or resized disk sr0
Feb 7 14:39:12 theta kernel: [564776.288231] VFS: busy inodes on changed media or resized disk sr0
Feb 7 14:39:12 theta kernel: [564776.297599] VFS: busy inodes on changed media or resized disk sr0
Feb 7 14:39:13 theta kernel: [564777.294194] VFS: busy inodes on changed media or resized disk sr0
Feb 7 14:39:14 theta kernel: [564778.288487] VFS: busy inodes on changed media or resized disk sr0
Feb 7 14:39:14 theta kernel: [564778.297790] VFS: busy inodes on changed media or resized disk sr0
Feb 7 14:39:15 theta kernel: [564779.287965] VFS: busy inodes on changed media or resized disk sr0
Feb 7 14:39:16 theta kernel: [564780.288390] VFS: busy inodes on changed media or resized disk sr0
Feb 7 14:39:16 theta kernel: [564780.297835] VFS: busy inodes on changed media or resized disk sr0
Feb 7 14:39:17 theta kernel: [564781.288703] VFS: busy inodes on changed media or resized disk sr0

It means your cdrom drive has been ejected without unmounting. Check this by typing this in your terminal:
mount
If this shows a line like:
/dev/sr0 on /media/cdrom1 type iso9660 (ro,nosuid,nodev,utf8)
then your cdrom has been ejected. Try typing:
sudo umount /dev/sr0
This should unmount the cdrom. If it doesn't work, maybe try:
sudo umount -f /dev/sr0