From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760940Ab3LIJEU (ORCPT ); Mon, 9 Dec 2013 04:04:20 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:48447 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755451Ab3LIJEN (ORCPT ); Mon, 9 Dec 2013 04:04:13 -0500 Date: Mon, 9 Dec 2013 01:05:30 -0800 From: Greg Kroah-Hartman To: Axel Lin Cc: Rob Landley , Al Viro , Kay Sievers , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH] devtmpfs: Calling delete_path() only when necessary Message-ID: <20131209090530.GA4586@kroah.com> References: <1384589723.7840.1.camel@phoenix> <1386125959.1974.309@driftwood> <20131209064654.GA20485@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.22 (2013-10-16) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Dec 09, 2013 at 04:54:29PM +0800, Axel Lin wrote: > 2013/12/9 Greg Kroah-Hartman : > > On Wed, Dec 04, 2013 at 02:44:14PM +0800, Axel Lin wrote: > >> 2013/12/4 Rob Landley : > >> > On 11/16/2013 02:15:23 AM, Axel Lin wrote: > >> >> > >> >> The deleted variable is always 1 in current code. > >> >> Initialize deleted variable to be 0, so delete_path() will be called only > >> >> when > >> >> necessary. > >> >> > >> >> Signed-off-by: Axel Lin > >> > > >> > > >> > I'm not seeing this in linux-next, or a reply on the web archive. Assuming > >> > nobody's objected to this, you might want to forward it to > >> > trivial@kernel.org. > >> > > >> > That said, you could describe what it _does_ a little more? > >> > >> I was expecting Greg to pick up this patch. > >> > >> I thought the description is pretty clear. > >> What the patch does is changing the init value of deleted variable to 0. > >> The intention of this change is to avoid unnecessary delete_path() call. > > > > I agree the logic is a bit odd here, but are you seeing an "unnecessary" > > delete_path() call happening? The code has always been like this from > > what I can tell... > > Honestly, I havn't see the "unnecessary" delete_path() call happening druing my > test. I look at the code when I was debugging a hangup issue. > (In the end, I think the issue is not related to the devtmpfs code.) > But I found the logic for the deleted variable looks odd. > There are below possible (unlikely) case: > When strchr(nodename, '/') != 0 and > 1. If dentry->d_inode is NULL > 2. vfs_getattr returns error > 3. vfs_unlink returns error except -ENOENT. > > In these cases, delete_path() will fail anyway. > > Although this is a unlikely case, and I know the code is there since initial > commit. But I think it's still good to fix it. Have you tested your patch to verify nothing breaks?