From: "Darrick J. Wong" <darrick.wong@oracle.com>
To: Josef 'Jeff' Sipek <jeffpc@josefsipek.net>
Cc: xfs@oss.sgi.com
Subject: Re: [PATCH] xfs: check sizes of XFS on-disk structures at compile time
Date: Fri, 22 Jan 2016 14:01:45 -0800 [thread overview]
Message-ID: <20160122220145.GA26408@birch.djwong.org> (raw)
In-Reply-To: <20160120154035.GH1366@meili.valhalla.31bits.net>
On Wed, Jan 20, 2016 at 10:40:36AM -0500, Josef 'Jeff' Sipek wrote:
> 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.
I moved the function to a separate header file and changed the declaration to:
static inline void __init xfs_check_ondisk_structs(void)
With any luck that should compile down to an empty inline function which should
be optimized out of the resulting code. Worst case it's a separate function
that gets discarded after the module loads. If Dave doesn't object, I'll leave
it enabled for all builds.
--D
>
> Just my 2 cents,
>
> Jeff.
>
> --
> Only two things are infinite, the universe and human stupidity, and I'm not
> sure about the former.
> - Albert Einstein
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next prev parent reply other threads:[~2016-01-22 22:01 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-11 23:26 [PATCH] xfs: check sizes of XFS on-disk structures at compile time Darrick J. Wong
2016-01-12 14:01 ` Brian Foster
2016-01-13 18:25 ` Eric Sandeen
2016-01-15 21:05 ` Darrick J. Wong
2016-01-15 20:58 ` Darrick J. Wong
2016-01-15 22:52 ` Dave Chinner
2016-01-20 5:12 ` Darrick J. Wong
2016-01-20 15:40 ` Josef 'Jeff' Sipek
2016-01-22 22:01 ` Darrick J. Wong [this message]
2016-02-01 5:06 ` Dave Chinner
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