From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx3-rdu2.redhat.com ([66.187.233.73]:50920 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726393AbeGLIwd (ORCPT ); Thu, 12 Jul 2018 04:52:33 -0400 Date: Thu, 12 Jul 2018 10:43:54 +0200 From: Karel Zak To: Yecheng Fu Cc: Matthew Wilcox , Alexander Viro , linux-fsdevel@vger.kernel.org Subject: Re: [PATCH v2] vfs: use "none" if mount source is empty string Message-ID: <20180712084354.2npy5ram3zmhtagp@ws.net.home> References: <1524109641-45617-1-git-send-email-cofyc.jackson@gmail.com> <20180419113256.GC5556@bombadil.infradead.org> <20180515051758.GA10231@jupiter.local> <20180712022848.GA89138@jupiter.local> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180712022848.GA89138@jupiter.local> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Thu, Jul 12, 2018 at 10:29:50AM +0800, Yecheng Fu wrote: > On Tue, May 15, 2018 at 01:18:00PM +0800, Yecheng Fu wrote: > > On Thu, Apr 19, 2018 at 04:32:56AM -0700, Matthew Wilcox wrote: > > > On Thu, Apr 19, 2018 at 11:47:21AM +0800, Yecheng Fu wrote: > > > > `libmount` from util-linux and many softwares in userspace (e.g. > > > > kubelet) did not expect empty string as mount source: > > > > > > > > ``` > > > > $ mount -t tmpfs "" /mnt/tmpfs > > > > $ findmnt /mnt/tmpfs > > > > findmnt: /proc/self/mountinfo: parse error at line 51 > > > > $ cat /proc/self/mountinfo | grep -P '\/mnt\/tmpfs' > > > > 74 25 0:59 / /mnt/tmpfs rw,relatime shared:38 - tmpfs rw > > > > $ cat /proc/self/mounts | grep -P '\/mnt\/tmpfs' > > > > /mnt/tmpfs tmpfs rw,relatime 0 0 > > > > ``` > > > > > > > > `source` field in mounts/mountinfo is empty, which breaks a lot of > > > > mounts/mountinfo parsers. > > > > > > > > This fixes issues in parsing when user uses empty string as mount > > > > source. > > > > > > > > Cc: Karel Zak > > > > Signed-off-by: Yecheng Fu > > > > > > Reviewed-by: Matthew Wilcox > > > > hi, I'm a newbie here. Will this be merged or is there still something I > > need to do? > > > > I had submitted a patch to [util-linux](https://github.com/karelzak/util-linux/pull/619). Karel prefer kernel side bugfix than rewrite all the sscanf() stuff and I agree. Kernel side bugfix also fixes all parsers too. > > > > -- > > Yecheng Fu > > hi, didn't receive any updates for months, sorry to ping again in case > someone missed it. > > Karel patched util-linux to work around this issue now [^1], but I hope this > can be fixed on kernel side too to improve compatibility. I agree. I'm absolutely sure that in userspace are many many another places where nobody expects empty mount source in /proc/self/mountinfo. It would be really nice to use there "none" as placeholder. Karel -- Karel Zak http://karelzak.blogspot.com