Re: [PATCH] xfs: check sizes of XFS on-disk structures at compile time

Josef 'Jeff' Sipek
2016-01-20T15:40:41Z

On Sat, Jan 16, 2016 at 09:52:19AM +1100, Dave Chinner wrote:
> On Fri, Jan 15, 2016 at 12:58:01PM -0800, Darrick J. Wong wrote:
> > On Mon, Jan 11, 2016 at 03:26:57PM -0800, Darrick J. Wong wrote:
> > > Check the sizes of XFS on-disk structures when compiling the kernel.
> > > Use this to catch inadvertent changes in structure size due to padding
> > > and alignment issues, etc.
> > >
> > > Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> ....
> > > + XFS_CHECK_STRUCT_SIZE(struct xfs_efi_log_format_64, 32);
> > > + XFS_CHECK_STRUCT_SIZE(struct xfs_efd_log_format_32, 28);
> > > + XFS_CHECK_STRUCT_SIZE(struct xfs_efd_log_format_64, 32);
> > > + XFS_CHECK_STRUCT_SIZE(struct xfs_dq_logformat, 24);
> > > + XFS_CHECK_STRUCT_SIZE(struct xfs_qoff_logformat, 20);
> > > + XFS_CHECK_STRUCT_SIZE(struct xfs_icreate_log, 28);
> > > +}
> >
> > Perhaps this huge function ought to hide away in its own file?
>
> Yes, I think that's a good idea, and I think it should only be built
> on debug builds, too.

Doesn't this turn into nothingness as far as the generated binary is
concerned? Because if it does, I don't see a reason to keep it debug-only.
Afterall, non-debug builds need to be correct and these are pretty important
checks. We certainly don't want another ARM structure padding & alignment
fiasco.

Just my 2 cents,

Jeff.

--
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