I am running 12.04 LTS, and almost every time I shut down my system, my root fails to mount on the next bootup, usually after an update.

In this particular case, I can see my filesystem when running on live CD, but every time I boot, I see the following sequence of messages cycle in an endless loop (process IDs removed):

ata1.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x0

ata1.00: BMDMA stat 0x24

ata1.00: failed command: READ DMA

ata1.00: cmd c8/00:08:b0:f7:46/00:00:00:00:00/e0

         res 51/40:08:b0:f7:46/40:02:02:00:00/e0 Emask 0x9 (media error)

ata1.00: status:{DRDY ERR}

ata1.00:error:{UNC}

end_request: I/O error, dev sda, sector 4650928

I boot off of a relatively new 60GB solid state disk drive, and in the past when I have run into this issue, I use fsck to detect and fix errors. But fsck runs clean on my partition, so i am uncertain how to approach the problem.