On Fri, Aug 13, 2021 at 01:52:00PM -0400, Theodore Ts'o wrote:
> 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)_/¯
Perhaps in that time someone can donate a disused Opteron 140 system?
Assuming the motherboard capacitors haven't since lost their mojo.
> 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 <djwong@xxxxxxxxxx>
> 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. ]
Even better!
>
> Signed-off-by: Darrick J. Wong <djwong@xxxxxxxxxx>
> Signed-off-by: Theodore Ts'o <tytso@xxxxxxx>
>
> 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.
Um... the conffile changes only disable the warning for Hurd?
> + */
> + 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,
Nit: need a closing parentheses after '2038' or no opening paren.
> +except for file systems created for the GNU Hurd, which does not support
> +inodes larger than 128 bytes.
I wonder if this statementt about Hurd this belongs in the conffile as a
comment in the hurd section?
--D
> +.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
> }
