[PATCH, RFC] xfs: be more forgiving of a v4 secondary sb w/ junk in v5 fields

[Ben Myers]

On Thu, Aug 15, 2013 at 05:41:49PM -0500, Eric Sandeen wrote:
> Today, if xfs_sb_read_verify encounters a v4 superblock
> with junk past v4 fields which includes data in sb_crc,
> it will be treated as a failing checksum and significant
> corruption.
> 
> There are known prior bugs which leave junk at the end
> of the superblock; we don't need to actually fail the
> verification in this case if other checks pan out ok.
> 
> So if this is a secondary superblock, and the primary
> superblock is not V5, don't treat this as a serious
> checksum failure.
> 
> We should probably check the garbage condition as
> we do in xfs_repair, and possibly warn about it
> or self-heal, but that's a different scope of work.
> 
> Signed-off-by: Eric Sandeen <sandeen at redhat.com>

Eric... is the one you're talking about?