To: jack@suse.cz
CC: miklos@szeredi.hu, gorcunov@gmail.com, akpm@linux-foundation.org,
       linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
       jack@suse.cz
In-reply-to: <20080125152702.GD28856@atrey.karlin.mff.cuni.cz> (message from
	Jan Kara on Fri, 25 Jan 2008 16:27:02 +0100)
Subject: Re: [patch 25/26] mount options: fix udf
References: <20080124193341.166753833@szeredi.hu> <20080124193456.220272889@szeredi.hu> <20080124202034.GC6724@cvg> <E1JIKsD-0001Kf-Bz@pomaz-ex.szeredi.hu> <20080125152702.GD28856@atrey.karlin.mff.cuni.cz>
Message-Id: <E1JIQop-0002AW-TW@pomaz-ex.szeredi.hu>
From: Miklos Szeredi <miklos@szeredi.hu>
Date: Fri, 25 Jan 2008 16:50:15 +0100
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1684
Lines: 41

> > > | +	/* is this correct? */
> > > | +	if (sbi->s_anchor[2] != 0)
> > > | +		seq_printf(seq, ",anchor=%u", sbi->s_anchor[2]);
> > > 
> > > you know, I would prefer to use form UDF_SB_ANCHOR(sb)[2]
> > > in sake of style unification but we should wait for Jan's
> > > decision (i'm not the expert in this area ;)
> > 
> > I think UDF_SB_ANCHOR macro was removed by some patch in -mm.
>   Yes, it's going to be removed so don't use it. Actually, basing this
> patch on top of -mm is a good idea because there are quite some changes
> in Andrew's queue.
> 
> > I'm more interested if the second element of the s_anchor array really
> > does always have the value of the 'anchor=N' mount option.  I haven't
> > been able to verify that fully.  Do you have some insight into that?
>   As Cyrill wrote, it could be zeroed out in case there is no anchor in
> the specified block. So I guess you have to store the passed value
> somewhere else..

But in that case, would the value of the anchor= option matter?

This is actually a somewhat philosophical question about what the
mount options in /proc/mounts mean:

 1) Options _given_ by the user for the mount
 2) Options which are _effective_ for the mount

If we take interpretation 2) and there was no anchor (whatever that
means), then the anchor=N option wasn't effective, and not giving it
would have had the same effect.

This could be confusing to the user, though...

Thanks,
Miklos
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