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Subject: Re: [PATCH 02/16] GFS2: Core locking interface
From: Steven Whitehouse <swhiteho@redhat.com>
To: Jan Engelhardt <jengelh@linux01.gwdg.de>
Cc: linux-kernel@vger.kernel.org, Russell Cattelan <cattelan@redhat.com>,
       David Teigland <teigland@redhat.com>, Ingo Molnar <mingo@elte.hu>,
       hch@infradead.org
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Organization: Red Hat (UK) Ltd
Date: Mon, 04 Sep 2006 16:40:01 +0100
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Hi,

On Mon, 2006-09-04 at 11:22 +0200, Jan Engelhardt wrote:
> Hi,
> 
> 
> >Unfortunately thats not possible as the struct gfs2_sbd is actually
> >changed lower down the call chain, but only in the lock_dlm module.
> 
> +void gfs2_lm_unmount(struct gfs2_sbd *sdp)
> +{
> +	if (likely(!test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
> +		gfs2_unmount_lockproto(&sdp->sd_lockstruct);
> +}
> 
> I can't follow... test_bit does not modify *sdp or sdp->sd_flags, and
> gfs2_unmount_lockproto does not either.
> 
sd_lockstruct is part of the superblock and fields in the lockstruct are
changed by (for example) fs/gfs2/locking/dlm/mount.c: gdlm_unmount() so
I don't think its valid to mark the superblock const here (despite being
a great fan of using const in general).


Steve.