[PATCH] xfs_db: check on-disk structure sizes

[Christoph Hellwig]

On Wed, Jan 13, 2016 at 12:02:36AM -0600, Eric Sandeen wrote:
> > As I've pointed out previously to Darrick: xfstests:/tests/xfs/122
> > 
> > Make that build again, update it.
> > 
> Oh, I went looking for that and missed it somehow, thought it had been removed.   Ok then!

The real issue is that build environment change alignments.  32 vs 64
bit builds are obvious, but on some architectures different ABIs have
different alignments (we had some fun with ARM in that regard),
nevermind the equivalents to IRIX n32 popping up everywhere these days
that make things complicated.

I'd really love to have Darrick's check in xfs_format.h as an opt-in
if a build time assert is provided - that way every user can check it
doesn't screw up the structures.