From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753080AbdK1Wlc (ORCPT ); Tue, 28 Nov 2017 17:41:32 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:46456 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752229AbdK1Wl3 (ORCPT ); Tue, 28 Nov 2017 17:41:29 -0500 Date: Tue, 28 Nov 2017 14:41:27 -0800 From: Andrew Morton To: Joe Perches Cc: OGAWA Hirofumi , David Howells , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH] fat: Fix sb_rdonly() change Message-Id: <20171128144127.e4903df58c8c3e7c783dd61b@linux-foundation.org> In-Reply-To: <1511506294.8230.6.camel@perches.com> References: <87mv3d5x51.fsf@mail.parknet.co.jp> <87ine15wzx.fsf@mail.parknet.co.jp> <1511470178.5308.2.camel@perches.com> <873754i512.fsf@mail.parknet.co.jp> <1511506294.8230.6.camel@perches.com> X-Mailer: Sylpheed 3.4.1 (GTK+ 2.24.23; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 23 Nov 2017 22:51:34 -0800 Joe Perches wrote: > On Fri, 2017-11-24 at 15:07 +0900, OGAWA Hirofumi wrote: > > Joe Perches writes: > > > > > On Thu, 2017-11-23 at 15:29 +0900, OGAWA Hirofumi wrote: > > > > Ouch forgot to add stable@ > > > > > > > > -- > > > > commit bc98a42c1f7d0f886c0c1b75a92a004976a46d9f introduced bug. > > > > > > I think your commit message needs a bit more information. > > > > > > It'd be useful to describe that the introduction of > > > sb_rdonly converted the bitwise & to a boolean and so > > > this conversion and comparison was made defective. > > > > > > Are there any other instances of defective comparisons? > > > > Please ask to that patch author. > > The patch author, David Howells, is on the cc list. > > btw: > > It seems all the the other uses use a (bool) cast of the > (*flags & MS_RDONLY) and a comparison of sb_rdonly(sb). Sentence is hard to understand. > It would make sense to change the argument type of the > ext[24]_setup_super int read_only arg to bool to match > the sb_rdonly() type. I did this: : From: OGAWA Hirofumi : Subject: fat: Fix sb_rdonly() change : : bc98a42c1f7d0f ("VFS: Convert sb->s_flags & MS_RDONLY to sb_rdonly(sb)") : converted fat_remount():new_rdonly from a bool to an int. However : fat_remount() depends upon the compiler's conversion of a non-zero integer : into boolean `true'. : : Fix it by switching `new_rdonly' back into a bool. : : Link: http://lkml.kernel.org/r/87mv3d5x51.fsf@mail.parknet.co.jp : Fixes: bc98a42c1f7d0f8 ("VFS: Convert sb->s_flags & MS_RDONLY to sb_rdonly(sb)") : Signed-off-by: OGAWA Hirofumi : Cc: Joe Perches : Cc: David Howells : Cc: : Signed-off-by: Andrew Morton : --- : : fs/fat/inode.c | 2 +- : 1 file changed, 1 insertion(+), 1 deletion(-) : : diff -puN fs/fat/inode.c~fat-fix-sb_rdonly-change fs/fat/inode.c : --- a/fs/fat/inode.c~fat-fix-sb_rdonly-change : +++ a/fs/fat/inode.c : @@ -779,7 +779,7 @@ static void __exit fat_destroy_inodecach : : static int fat_remount(struct super_block *sb, int *flags, char *data) : { : - int new_rdonly; : + bool new_rdonly; : struct msdos_sb_info *sbi = MSDOS_SB(sb); : *flags |= SB_NODIRATIME | (sbi->options.isvfat ? 0 : SB_NOATIME); : : _