On PS3, hard disk's file system is corrupted, how to restore it?

[Jasthi]

it all started with my Black Ops file being corrupted and saying that I have to delete it before I can play.
So I tried deleting it and it came up with the error code 80131000 or something extremely similar.//
I then held down the button to force to turn it off because it was frozen. Then when I turned the PS3 back on a message popped up saying 'The hard disk's file system is corrupted and will be restored'. I click OK. It then decides to say 'An error occurred during the restore operation. The hard disk must be formatted. All data on the hard disk will be deleted during formatting. Do you want to format? And of course I don't want to lose all my data, hence asking this.

[Sawan123]

I think there was something like that a while ago and may have lost data, but has not had one problem after the restoration was done, this could be from a game that had corrupted data on the disk or failure of a game. A good rule is occasionally back up your data on a flash drive.

[Karleen]

I was also suffering from the same issue, I read on the forums that the main reason for this is when people shut of the PS3 while it's saving data to the HDD, but still I am not sure about that. I know only that if you directly shut down then something that's in the process of saving anything.