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=-13.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,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 7AD20C432BE for ; Fri, 13 Aug 2021 17:55:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 57A57610A4 for ; Fri, 13 Aug 2021 17:55:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230377AbhHMRz6 (ORCPT ); Fri, 13 Aug 2021 13:55:58 -0400 Received: from outgoing-auth-1.mit.edu ([18.9.28.11]:53943 "EHLO outgoing.mit.edu" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S230316AbhHMRzk (ORCPT ); Fri, 13 Aug 2021 13:55:40 -0400 Received: from cwcc.thunk.org (pool-72-74-133-215.bstnma.fios.verizon.net [72.74.133.215]) (authenticated bits=0) (User authenticated as tytso@ATHENA.MIT.EDU) by outgoing.mit.edu (8.14.7/8.12.4) with ESMTP id 17DHq0aT013255 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 13 Aug 2021 13:52:01 -0400 Received: by cwcc.thunk.org (Postfix, from userid 15806) id 5572C15C37C1; Fri, 13 Aug 2021 13:52:00 -0400 (EDT) Date: Fri, 13 Aug 2021 13:52:00 -0400 From: "Theodore Ts'o" To: "Darrick J. Wong" Cc: Andreas Dilger , linux-ext4 Subject: Re: [PATCH v2] mke2fs: warn about missing y2038 support when formatting fresh ext4 fs Message-ID: References: <20210812232222.GE3601392@magnolia> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20210812232222.GE3601392@magnolia> Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org On Thu, Aug 12, 2021 at 04:22:22PM -0700, Darrick J. Wong wrote: > Note that we /don't/ warn about these things if the user has signalled > that they want an old format such as ext2, ext3, or hurd. Everyone > should know by now that those are legacy. So I took a closer look, and it turns out that we changed the default inode size for ext2 and ext3 file systems in 2008 (see commit b1631cce648e ("Create new filesystems with 256-byte inodes by default"), in e2fsprogs 1.40.4. Even a positively antedeluvian distro such as RHEL 7 uses e2fsprogs 1.42.9, and RHEL 6 EOL'ed November 30th, 2020. There were only two cases where we created file systems with 128 byte inodes --- "small" and "floppy" sized file systems, and for the GNU Hurd, which only supports the original 128 byte inode. What will GNU Hurd do in 16.5 years? ¯\_(ツ)_/¯ Given that, I think we can simplify the patch a little, and just use a mke2fs.conf boolean to disable the warning message. What do folks think? - Ted commit f569fe86caddf964973ed35cdf36ed520ef23a0c Author: Darrick J. Wong Date: Thu Aug 12 16:22:22 2021 -0700 mke2fs: warn about missing y2038 support when formatting fresh ext4 fs Filesystems with 128-byte inodes do not support timestamps beyond the year 2038. Since we're now less than 16.5 years away from that point, it's time to start warning users about this lack of support when they format an ext4 filesystem with small inodes. (Note that even for ext2 and ext3, we changed the default for non-small file systems in 2008 in commit commit b1631cce648e ("Create new filesystems with 256-byte inodes by default").) So change the mke2fs.conf file to specify 256-byte inodes even for small filesystems, and then add a warning to mke2fs itself if someone is trying to make us format a file system with 128-byte inodes. This can be suppressed by setting the boolean option warn_y2038_dates in the mke2fs.conf file to false, which we do in the case of GNU Hurd, since it only supports 128 byte inodes as of this writing. [ Patch reworked by tytso to only warn in the case of GNU Hurd, since the default for ext2/ext3 was changed for all but small file systems in 2008. ] Signed-off-by: Darrick J. Wong Signed-off-by: Theodore Ts'o diff --git a/misc/mke2fs.c b/misc/mke2fs.c index 92003e11..881ffd31 100644 --- a/misc/mke2fs.c +++ b/misc/mke2fs.c @@ -2603,6 +2603,17 @@ profile_error: exit(1); } + /* + * Warn the user that filesystems with 128-byte inodes will + * not work properly beyond 2038. This can be suppressed via + * a boolean in the mke2fs.conf file, and we will disable this + * warning for ext2, ext3, and hurd file systems. + */ + if (inode_size == EXT2_GOOD_OLD_INODE_SIZE && + get_bool_from_profile(fs_types, "warn_y2038_dates", 1)) + printf( +_("128-byte inodes cannot handle dates beyond 2038 and are deprecated\n")); + /* Make sure number of inodes specified will fit in 32 bits */ if (num_inodes == 0) { unsigned long long n; diff --git a/misc/mke2fs.conf.5.in b/misc/mke2fs.conf.5.in index 08bb9488..62d0fdb5 100644 --- a/misc/mke2fs.conf.5.in +++ b/misc/mke2fs.conf.5.in @@ -505,6 +505,13 @@ This relation specifies the base file name for the huge files. This relation specifies the (zero-padded) width of the field for the huge file number. .TP +.I warn_y2038_dates +This boolean relation specifies wheather mke2fs will issue a warning +when creating a file system with 128 byte inodes (and so therefore will +not support dates after January 19th, 2038. The default value is true, +except for file systems created for the GNU Hurd, which does not support +inodes larger than 128 bytes. +.TP .I zero_hugefiles This boolean relation specifies whether or not zero blocks will be written to the hugefiles while diff --git a/misc/mke2fs.conf.in b/misc/mke2fs.conf.in index 01e35cf8..05680992 100644 --- a/misc/mke2fs.conf.in +++ b/misc/mke2fs.conf.in @@ -12,16 +12,13 @@ } ext4 = { features = has_journal,extent,huge_file,flex_bg,metadata_csum,64bit,dir_nlink,extra_isize - inode_size = 256 } small = { blocksize = 1024 - inode_size = 128 inode_ratio = 4096 } floppy = { blocksize = 1024 - inode_size = 128 inode_ratio = 8192 } big = { @@ -44,4 +41,5 @@ hurd = { blocksize = 4096 inode_size = 128 + warn_y2038_dates = 0 }