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Date: Mon, 7 Sep 2009 09:39:27 +0200
From: Nick Piggin <npiggin@suse.de>
To: Jens Axboe <jens.axboe@oracle.com>
Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [patch 04/33] fs: brlock vfsmount_lock
Message-ID: <20090907073927.GG1875@wotan.suse.de>
References: <20090904065142.114706411@nick.local0.net> <20090904065534.447753909@nick.local0.net> <20090904151908.GX18599@kernel.dk>
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On Fri, Sep 04, 2009 at 05:19:09PM +0200, Jens Axboe wrote:
> On Fri, Sep 04 2009, npiggin@suse.de wrote:
> > Index: linux-2.6/fs/namei.c
> > ===================================================================
> > --- linux-2.6.orig/fs/namei.c
> > +++ linux-2.6/fs/namei.c
> > @@ -679,15 +679,16 @@ int follow_up(struct path *path)
> >  {
> >  	struct vfsmount *parent;
> >  	struct dentry *mountpoint;
> > -	spin_lock(&vfsmount_lock);
> > +
> > +	vfsmount_read_unlock();
> >  	parent = path->mnt->mnt_parent;
> >  	if (parent == path->mnt) {
> > -		spin_unlock(&vfsmount_lock);
> > +		vfsmount_read_unlock();
> >  		return 0;
> 
> Hmm, that looks a bit off.

Thanks Jens, good catch. Yes I haven't actually even tested NFS or
NFSD yet, which I should do soon because they do some interesting
things with the dcache.