Jbd2 async problem

[Rock Lee]

Hi:

> Consider the case of 75 metadata blocks in the journal, with one bad block.
>
> Which results in less total damage when the journal is replayed:
>
> 1) Applying the 74 good ones (if possible) and complain about the one bad one?
>
> 2) Refusing to deal with *any* of them.

Indeed, I would like to choose 1) to keep my filesystem from less
damage. However, a transaction means the whole operation is atomic, it
could not be seperated in replay. If bad blocks could just be ignore,
there's no need of descriptor + commit pair, just copy crc right
blocks back to filesystem could achieve our goals.

-- 
Cheers,
Rock