From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752186AbeENDjr (ORCPT ); Sun, 13 May 2018 23:39:47 -0400 Received: from szxga06-in.huawei.com ([45.249.212.32]:45985 "EHLO huawei.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1752028AbeENDjq (ORCPT ); Sun, 13 May 2018 23:39:46 -0400 Subject: Re: [PATCH] f2fs: Fix deadlock in shutdown ioctl To: Sahitya Tummala , Jaegeuk Kim , CC: References: <1525958444-5579-1-git-send-email-stummala@codeaurora.org> From: Chao Yu Message-ID: Date: Mon, 14 May 2018 11:39:42 +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: <1525958444-5579-1-git-send-email-stummala@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 2018/5/10 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, > > Signed-off-by: Sahitya Tummala > --- > fs/f2fs/file.c | 5 ----- > 1 file changed, 5 deletions(-) > > diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c > index b926df7..2c2e61b 100644 > --- a/fs/f2fs/file.c > +++ b/fs/f2fs/file.c > @@ -1835,10 +1835,6 @@ static int f2fs_ioc_shutdown(struct file *filp, unsigned long arg) > if (get_user(in, (__u32 __user *)arg)) > return -EFAULT; > > - ret = mnt_want_write_file(filp); > - if (ret) > - return ret; > - > switch (in) { > case F2FS_GOING_DOWN_FULLSYNC: > sb = freeze_bdev(sb->s_bdev); > @@ -1878,7 +1874,6 @@ static int f2fs_ioc_shutdown(struct file *filp, unsigned long arg) > > f2fs_update_time(sbi, REQ_TIME); > out: > - mnt_drop_write_file(filp); > return ret; > } > >