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=-6.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 1BF8BC433FF for ; Sat, 10 Aug 2019 20:37:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D15E62085B for ; Sat, 10 Aug 2019 20:37:09 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="sdfxzAMk" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726455AbfHJUhI (ORCPT ); Sat, 10 Aug 2019 16:37:08 -0400 Received: from mail-ot1-f67.google.com ([209.85.210.67]:38418 "EHLO mail-ot1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725788AbfHJUhI (ORCPT ); Sat, 10 Aug 2019 16:37:08 -0400 Received: by mail-ot1-f67.google.com with SMTP id d17so145884795oth.5; Sat, 10 Aug 2019 13:37:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=jucnTNtmH8/DZ4WEOho6QZPjcUdP4+w0e+PDI8VoSe8=; b=sdfxzAMklg19nbBRvR7b/SyJ2lx3tBZc/bOKSlH4x1QeUPXaL8KC/Dcv6EuBdaTeVL x//XZTEPF72qqYRwHnK3/j6iVfEZno/YG5mOa7Uj9QzDlS6RcgQD5AXGatkdYK576KBr D2zWjvNLEz2T0ffgyRJmVNEcugLr6Nu/AhJ4HCPyddpRP6CxbDboQXtWzHlKydb9zRQL Riv6FDAgGgjVuYghsdiuUaLk0AlXVeakV4e7fmaERqQlJhnfcJoKx8z0MUw6C1lOoUvk wNjXa8UWzEjgrUqOm8wHuuo8OCh3pQvHUaBGizMHyj3tXQew2FD1lKSKzyT9bakopmfi 3xGQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=jucnTNtmH8/DZ4WEOho6QZPjcUdP4+w0e+PDI8VoSe8=; b=HyTmndnUQA1YkCY0HLEWQay1mnVjplJjTlFCJdYyoF/cjg7OUosGbBa2ktQVnjXOry osRcOY8bE8N71t6fAuRa+7S4+ddgmwrjYdqBN3h9tQ9HxQ9y1JZNBR2bGMuKnDepBl+X zHiOq8uFo9smN1kCQF6KNDaqlw9mhjlh69uVa2ZzPwB/yHPei7Wr1seZ6naJNTS/gpl2 aixcBWH9tNKsKMnkoJ1pmxm4SxOZgaIGabDu+u7F/wfehrkwtRltzt9o0PQivix2H6Yq MQPGr93o0xYFLtSA+izaqG7BGf5q8Pyup2LrZCs2PU1vNryWyNBMwJ4FBii0a+QcrrTt C85Q== X-Gm-Message-State: APjAAAWvxTKxqeYLQDqG/6vSsr7eYxHFA2Pi1ox/lNc8PSElCn6Jf5hh Ux/Qw0Xo0h23yXRIubknmMnhJADEe7zc/q4BJRtGU2Br X-Google-Smtp-Source: APXvYqwVH7AZegtiTKp16y6T54m5AFpdAElZ8MiuT0cJGR+Z8AVZcQj55YDRuf8crr90KNtUvZLI5tQMzRQRy86jpZQ= X-Received: by 2002:a5d:85c3:: with SMTP id e3mr27018354ios.265.1565469426677; Sat, 10 Aug 2019 13:37:06 -0700 (PDT) MIME-Version: 1.0 References: <20190730014924.2193-1-deepa.kernel@gmail.com> <20190730014924.2193-6-deepa.kernel@gmail.com> <12c095e595836a7ff7f2c7b2a32cb5544dd29b55.camel@codethink.co.uk> In-Reply-To: <12c095e595836a7ff7f2c7b2a32cb5544dd29b55.camel@codethink.co.uk> From: Deepa Dinamani Date: Sat, 10 Aug 2019 13:36:55 -0700 Message-ID: Subject: Re: [Y2038] [PATCH 05/20] utimes: Clamp the timestamps before update To: Ben Hutchings Cc: Alexander Viro , Linux Kernel Mailing List , Linux FS-devel Mailing List , y2038 Mailman List , Arnd Bergmann Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Aug 5, 2019 at 6:30 AM Ben Hutchings wrote: > > On Mon, 2019-07-29 at 18:49 -0700, Deepa Dinamani wrote: > > POSIX is ambiguous on the behavior of timestamps for > > futimens, utimensat and utimes. Whether to return an > > error or silently clamp a timestamp beyond the range > > supported by the underlying filesystems is not clear. > > > > POSIX.1 section for futimens, utimensat and utimes says: > > (http://pubs.opengroup.org/onlinepubs/9699919799/functions/futimens.html) > > > > The file's relevant timestamp shall be set to the greatest > > value supported by the file system that is not greater > > than the specified time. > > > > If the tv_nsec field of a timespec structure has the special > > value UTIME_NOW, the file's relevant timestamp shall be set > > to the greatest value supported by the file system that is > > not greater than the current time. > > > > [EINVAL] > > A new file timestamp would be a value whose tv_sec > > component is not a value supported by the file system. > > > > The patch chooses to clamp the timestamps according to the > > filesystem timestamp ranges and does not return an error. > > This is in line with the behavior of utime syscall also > > since the POSIX page(http://pubs.opengroup.org/onlinepubs/009695399/functions/utime.html) > > for utime does not mention returning an error or clamping like above. > > > > Same for utimes http://pubs.opengroup.org/onlinepubs/009695399/functions/utimes.html > > > > Signed-off-by: Deepa Dinamani > > --- > > fs/utimes.c | 17 +++++++++++++---- > > 1 file changed, 13 insertions(+), 4 deletions(-) > > > > diff --git a/fs/utimes.c b/fs/utimes.c > > index 350c9c16ace1..4c1a2ce90bbc 100644 > > --- a/fs/utimes.c > > +++ b/fs/utimes.c > > @@ -21,6 +21,7 @@ static int utimes_common(const struct path *path, struct timespec64 *times) > > int error; > > struct iattr newattrs; > > struct inode *inode = path->dentry->d_inode; > > + struct super_block *sb = inode->i_sb; > > struct inode *delegated_inode = NULL; > > > > error = mnt_want_write(path->mnt); > > @@ -36,16 +37,24 @@ static int utimes_common(const struct path *path, struct timespec64 *times) > > if (times[0].tv_nsec == UTIME_OMIT) > > newattrs.ia_valid &= ~ATTR_ATIME; > > else if (times[0].tv_nsec != UTIME_NOW) { > > - newattrs.ia_atime.tv_sec = times[0].tv_sec; > > - newattrs.ia_atime.tv_nsec = times[0].tv_nsec; > > + newattrs.ia_atime.tv_sec = > > + clamp(times[0].tv_sec, sb->s_time_min, sb->s_time_max); > > + if (times[0].tv_sec == sb->s_time_max || times[0].tv_sec == sb->s_time_min) > > This is testing the un-clamped value. > > > + newattrs.ia_atime.tv_nsec = 0; > > + else > > + newattrs.ia_atime.tv_nsec = times[0].tv_nsec; > > newattrs.ia_valid |= ATTR_ATIME_SET; > > } > > > > if (times[1].tv_nsec == UTIME_OMIT) > > newattrs.ia_valid &= ~ATTR_MTIME; > > else if (times[1].tv_nsec != UTIME_NOW) { > > - newattrs.ia_mtime.tv_sec = times[1].tv_sec; > > - newattrs.ia_mtime.tv_nsec = times[1].tv_nsec; > > + newattrs.ia_mtime.tv_sec = > > + clamp(times[1].tv_sec, sb->s_time_min, sb->s_time_max); > > + if (times[1].tv_sec >= sb->s_time_max || times[1].tv_sec == sb->s_time_min) > > Similarly here, for the minimum. > > I suggest testing for clamping like this: > > if (newattrs.ia_atime.tv_sec != times[0].tv_sec) > ... > if (newattrs.ia_mtime.tv_sec != times[1].tv_sec) > ... > > Ben. > > > + newattrs.ia_mtime.tv_nsec = 0; > > + else > > + newattrs.ia_mtime.tv_nsec = times[1].tv_nsec; > > newattrs.ia_valid |= ATTR_MTIME_SET; > > } Darrick pointed out that maybe we could use timestamp_truncate() here to clamp. I think it is ok to truncate to the right granularity also here. setattr callbacks do it already. So the diff here looks like below: - newattrs.ia_atime.tv_sec = - clamp(times[0].tv_sec, sb->s_time_min, sb->s_time_max); - if (times[0].tv_sec == sb->s_time_max || times[0].tv_sec == sb->s_time_min) - newattrs.ia_atime.tv_nsec = 0; - else - newattrs.ia_atime.tv_nsec = times[0].tv_nsec; + newattrs.ia_atime = timestamp_truncate(times[0], inode); Thanks, Deepa