Re: [PATCH 0/9] CRC support for superblock, ag headers, log and btree blocks

[Christoph Hellwig <hch@lst.de>]

On Fri, Sep 26, 2008 at 09:50:30AM +1000, Dave Chinner wrote:
> On Fri, Sep 26, 2008 at 12:56:13AM +0200, Christoph Hellwig wrote:
> > Here's an updated crc series for various metadata structures.  We're still
> > looking at the magic number in the log recovery case because getting down
> > a buffer type for the other structures wasn't quite as easy as for the
> > btree block.  I'll probably look into that again once we're done with all
> > data structures.
> 
> FWIW, I note that you haven't done anything with the AGFL yet. I was
> considering 2 different approaches. The first was to put the CRC for
> the AGFL into the AGF so that the internals of the AGFL do not change.
> However, that means we have interesting synchronisation problems
> with the CRC, so I don't think that will fly.
> 
> The other option was to reduce the number of slots in the AGFL by
> one and use the last slot to hold the CRC. I think that is OK to do;
> the AGFL can change size with different secotr size support, so I
> don't see this being a big problem. Nor do I think that we ever fill
> the AGFL up to it's full 128 slots during any transaction, so
> reducing the size by one should be safe.

Yes, my plan was to remove one slot, but use the first one for the crc.
Last one might actually be smarter.