From mboxrd@z Thu Jan  1 00:00:00 1970
From: Trond Myklebust <trond.myklebust@fys.uio.no>
Subject: Re: [PATCH 7/7] nfsd: nfs4xdr decode_stateid helper function
Date: Wed, 13 Aug 2008 14:59:52 -0400
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Cc: Benny Halevy <bhalevy@panasas.com>,
	NFS list <linux-nfs@vger.kernel.org>,
	pNFS Mailing List <pnfs@linux-nfs.org>,
	Chuck Lever <chucklever@gmail.com>
To: "J. Bruce Fields" <bfields@fieldses.org>
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On Wed, 2008-08-13 at 14:30 -0400, J. Bruce Fields wrote:
> On Wed, Aug 13, 2008 at 01:59:09PM -0400, Trond Myklebust wrote:
> > Which is a good reason for ditching the entire confusing typedef, and
> > replacing it with a packed structure instead:
> > 
> > struct stateid {
> > 	__be32 generation;
> > 	char opaque[12];
> > } __attribute__((packed));
> 
> So without the ((packed)), all arrays get aligned to 8-byte boundaries
> on 64-bit machines?  (What do I need to read to catch up here?)

A quick google showed up:

	http://sig9.com/articles/gcc-packed-structures

In any case, yes, the idea behind the packed attribute is to turn off
the field alignment.

Cheers
  Trond