Re: Device loses barrier support (was: Fixed patch for simple barriers.)

Andi Kleen
2008-12-04T14:09:21Z

> the 1st write request ends with success
> the 2nd write request ends with -EOPNOTSUPP
> the 3rd write request ends with success
>
> --- when you first see -EOPNOTSUPP, you have already corrupted filesystem
> (the 3rd write passed while the filesystem expected that it would be

There's no passing of requests during pvmove. It's a really strong
barrier.

> finished after the 2nd write) and you are in an interrupt context, where
> you can't reissue -EOPNOTSUPP request. So what do you want to do?

The barrier aware file systems I know of just resubmit synchronously when
a barrier fails.

-Andi