[PATCH 21/25] xfs: add buffer pre-write callback

[Christoph Hellwig]

On Wed, Oct 31, 2012 at 09:30:15AM +1100, Dave Chinner wrote:
> Perhaps. I just wrote it in a manner consistent with the iodone
> function where errors are returned in bp->b_error. Other functions
> pass buffer errors like this, too - xfs_buf_ioapply_map(),
> xfs_buf_read_map(), and _xfs_buf_ioapply() - so it's not unusual,
> really..
> 
> I can change it, but that involves changing every callback function
> as well and I don't see that as really necessary. i.e. they call
> xfs_buf_ioerror() already, so do we really need to have them return
> bp->b_error as well?

Let's keep it as is for now to make forward progress, we can still
figure out later if doing it differently is cleaner.