From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-11.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 916B9C433E1 for ; Tue, 21 Jul 2020 02:26:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 771D320734 for ; Tue, 21 Jul 2020 02:26:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727898AbgGUC0I (ORCPT ); Mon, 20 Jul 2020 22:26:08 -0400 Received: from out30-130.freemail.mail.aliyun.com ([115.124.30.130]:51494 "EHLO out30-130.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725862AbgGUC0I (ORCPT ); Mon, 20 Jul 2020 22:26:08 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R951e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e01419;MF=chge@linux.alibaba.com;NM=1;PH=DS;RN=6;SR=0;TI=SMTPD_---0U3MKo5._1595298289; Received: from chge-ali-mac.local(mailfrom:chge@linux.alibaba.com fp:SMTPD_---0U3MKo5._1595298289) by smtp.aliyun-inc.com(127.0.0.1); Tue, 21 Jul 2020 10:26:05 +0800 Subject: Re: [Ocfs2-devel] [PATCH] dlmfs: add a newline when printing 'capabilities' by sysfs To: Xiongfeng Wang , mark@fasheh.com, jlbec@evilplan.org, joseph.qi@linux.alibaba.com Cc: linux-kernel@vger.kernel.org, ocfs2-devel@oss.oracle.com References: <20200720082433.164311-1-wangxiongfeng2@huawei.com> From: Changwei Ge Message-ID: <5ee49484-1a8f-d4ed-c4b3-0d1d0cef4f52@linux.alibaba.com> Date: Tue, 21 Jul 2020 10:24:49 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:60.0) Gecko/20100101 Thunderbird/60.9.1 MIME-Version: 1.0 In-Reply-To: <20200720082433.164311-1-wangxiongfeng2@huawei.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi， I am afraid that doing so might introduce a compatible risk into exited systems which reply ocfs2/dlmfs. We can't guarantee that no system management tools is using the information reported from this file. Basically, ocfs2-tools works of top of it. But after a quick glance at the source, I didn't see side effect if this path applied. Better you can do some test if this patch breaks ocfs2-tools. Still my suggestion is that we don't try to touch this file as what I explained above. Thanks, Changwei On 7/20/20 4:24 PM, Xiongfeng Wang wrote: > When I cat module parameter 'capabilities' by sysfs, it displays as > follows. It's better to add a newline for easy reading. > > root@syzkaller:~# cat /sys/module/ocfs2_dlmfs/parameters/capabilities > bast stackglueroot@syzkaller:~# > > Signed-off-by: Xiongfeng Wang > --- > fs/ocfs2/dlmfs/dlmfs.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/fs/ocfs2/dlmfs/dlmfs.c b/fs/ocfs2/dlmfs/dlmfs.c > index ea868c6f9800..1f9c864ec09b 100644 > --- a/fs/ocfs2/dlmfs/dlmfs.c > +++ b/fs/ocfs2/dlmfs/dlmfs.c > @@ -82,8 +82,13 @@ static int param_set_dlmfs_capabilities(const char *val, > static int param_get_dlmfs_capabilities(char *buffer, > const struct kernel_param *kp) > { > - return strlcpy(buffer, DLMFS_CAPABILITIES, > + int cnt; > + > + cnt = strlcpy(buffer, DLMFS_CAPABILITIES, > strlen(DLMFS_CAPABILITIES) + 1); > + cnt += sprintf(buffer + cnt, "\n"); > + > + return cnt; > } > module_param_call(capabilities, param_set_dlmfs_capabilities, > param_get_dlmfs_capabilities, NULL, 0444); >