Re: [PATCH 23/22] xfs: add metadata CRC documentation

Dave Chinner
2013-04-07T23:08:38Z

On Fri, Apr 05, 2013 at 07:35:00AM -0400, Brian Foster wrote:
> On 04/05/2013 03:00 AM, Dave Chinner wrote:
> > xfs: add metadata CRC documentation
> >
> > From: Dave Chinner <dchinner@redhat.com>
> >
> > Add some documentation about the self describing metadata and the
> > code templates used to implement it.
> > +
> > +Runtime Validation
> > +------------------
> > +
> ...
> > +
> > +The first step in read verification is checking the magic number and determining
> > +whether CRC validating is necessary. If it is, the CRC32c is caluclated and
>
> What do you mean by "determining whether CRC validating is necessary?"
> In other words, it's not always enabled but rather triggered by
> something else that elevates suspicion on the object?

It is triggered by either the magic number indicating the object has
CRC checking or (xfs_sb_version_hascrc(sb) == true) indicating the
filesystem has metadata CRC checking enabled.

Cheers,

Dave.
--
Dave Chinner
david@fromorbit.com