From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752567AbeEPGtB (ORCPT ); Wed, 16 May 2018 02:49:01 -0400 Received: from szxga05-in.huawei.com ([45.249.212.191]:7692 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751550AbeEPGtA (ORCPT ); Wed, 16 May 2018 02:49:00 -0400 Subject: Re: [PATCH] f2fs: Fix deadlock in shutdown ioctl To: Sahitya Tummala CC: Jaegeuk Kim , , References: <1525958444-5579-1-git-send-email-stummala@codeaurora.org> <20180515075747.GA6293@codeaurora.org> From: Chao Yu Message-ID: <67bd2926-6851-0544-c24a-85dfa72aa70f@huawei.com> Date: Wed, 16 May 2018 14:48:42 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.3.0 MIME-Version: 1.0 In-Reply-To: <20180515075747.GA6293@codeaurora.org> Content-Type: text/plain; charset="windows-1252" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.134.22.195] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2018/5/15 15:57, Sahitya Tummala wrote: > On Mon, May 14, 2018 at 11:39:42AM +0800, Chao Yu wrote: >> On 2018/5/10 21:20, Sahitya Tummala wrote: >>> f2fs_ioc_shutdown() ioctl gets stuck in the below path >>> when going down with full sync (F2FS_GOING_DOWN_FULLSYNC) >>> option. >>> >>> __switch_to+0x90/0xc4 >>> percpu_down_write+0x8c/0xc0 >>> freeze_super+0xec/0x1e4 >>> freeze_bdev+0xc4/0xcc >>> f2fs_ioctl+0xc0c/0x1ce0 >>> f2fs_compat_ioctl+0x98/0x1f0 >>> >>> Fix this by not holding write access during this ioctl. >> >> I think we can just remove lock coverage for F2FS_GOING_DOWN_FULLSYNC path, for >> other path, we need to keep as it is. >> > > Thanks, I thought about it too but then I checked that XFS shutdown ioctl is > not taking any lock for this ioctl. Hence, I followed the same in F2FS. > Do you know why XFS is not taking any lock? I don't know. :( > Is it really needed in shutdown ioctl? IMO, yes, we should keep freeze and remount be aware of the shutdown operation. Thanks, > > -- > Sent by a consultant of the Qualcomm Innovation Center, Inc. > The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum. > >