After updating to the latest kernels, I found I was unable to boot my system properly. fsck was complaining about my boot partition, /dev/sda1, being "opened by another process?" and dropping me to the filesystem maintenance mode.

This was a rather wierd error, and since I could avoid it with my earlier kernels, I just stuck with them -- until I had to update my graphics drivers and found they were no longer being easily supported by my yum repositories.

So, I ended up finding a solution for me. It turns out I had two partitions that had identical ext2 labels: /dev/sda1 and /dev/sdb1, each of which had the label 'boot'. By using e2label to rename /dev/sdb1 to 'oldboot' (which it was) the problem was solved!

Hopefully this can help with others in the same situation. :)