From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx3-rdu2.redhat.com ([66.187.233.73]:56202 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S932078AbeE3VF5 (ORCPT ); Wed, 30 May 2018 17:05:57 -0400 Date: Wed, 30 May 2018 17:05:56 -0400 From: Vivek Goyal To: Miklos Szeredi Cc: linux-unionfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 16/28] ovl: Do not expose metacopy only dentry from d_real() Message-ID: <20180530210556.GD2717@redhat.com> References: <20180529144612.16675-1-mszeredi@redhat.com> <20180529144612.16675-17-mszeredi@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180529144612.16675-17-mszeredi@redhat.com> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Tue, May 29, 2018 at 04:46:00PM +0200, Miklos Szeredi wrote: > From: Vivek Goyal > > Metacopy dentry/inode is internal to overlay and is never exposed outside > of it. Exception is metacopy upper file used for fsync(). Modify d_real() > to look for dentries/inode which have data, but also allow matching upper > inode without data for the fsync case. > Hi Miklos, I am not able to see how in fsync() path d_real() gets called. If we decide to do fsync() on upper metacopy, then opening upper will not go through d_real(). And we never issue fsync() on lower. So I am scratching my head while trying to understand the d_real() and fsync() connection. Thanks Vivek > Signed-off-by: Vivek Goyal > Reviewed-by: Amir Goldstein > Signed-off-by: Miklos Szeredi > --- > fs/overlayfs/super.c | 7 +++++-- > 1 file changed, 5 insertions(+), 2 deletions(-) > > diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c > index e0326a686f45..6687d547ec6b 100644 > --- a/fs/overlayfs/super.c > +++ b/fs/overlayfs/super.c > @@ -101,10 +101,13 @@ static struct dentry *ovl_d_real(struct dentry *dentry, > } > > real = ovl_dentry_upper(dentry); > - if (real && (!inode || inode == d_inode(real))) > + if (real && (inode == d_inode(real))) > return real; > > - real = ovl_dentry_lower(dentry); > + if (real && !inode && ovl_has_upperdata(d_inode(dentry))) > + return real; > + > + real = ovl_dentry_lowerdata(dentry); > if (!real) > goto bug; > > -- > 2.14.3 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-unionfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html