Bug#1030846: Bug#1030939: e2fsprogs: generates filesystems that grub-install doesn't recognize

[Theodore Ts'o]

There is another issue with vmdb2 if you are using XFS.  Starting with
xfsprogs 5.15 (which is already in testing), bigtime is enabled by
default, so that newly created XFS file systems won't be subject to
timestamp overflow in 2038.  Grub didn't land support for this feature
until 8b1e5d1936ff ("fs/xfs: Add bigtime incompat feature support") in
May 2021, despite the fact that XFS has had this feature for years and
years and years.

So if you aren't using the latest security fixes, and you are using
XFS as the boot partition --- it won't work on buster and bullseye.
"Fortunately", there were were massive number security vulnerabilities
in grub2 which forced a backport of grub2 2.06 to bullseye and buster,
so if you have the security updates enabled, you'll probably be OK ---
but it was only because of massive number of security problems forced
that backport.


In any case, a version of grub that will support the csum_seed feature
will be landing in Bookworm in just a few days.  So at that point,
you'll be able to create VM images for Bookworm and Sid that will work
with the e2fsprogs in sid.  The current plan of record is that it will
only be at that point that e2fsprogs will be allowed to migrate into
Bookworm.

For slowly moving upstreams like grub2, distributions *have* to take
updates before grub2 finally gets around to doing a release --- to get
security fixes if nothing else!  The support for csum_seed has been in
Fedora and other distributions for a while, since the patches had
landed in grub2 in June 2021.  I probably should have made sure the
feature had landed in Debian's grub2 packaging earlier; that's my bad,
and my apologies for that.

Note that Debian's grub2 has well over 100 patches, nearly all of
which are backports from grub2's git repo.  So the argument that
"there doesn't exist a formally released grub2 release" isn't
particularly compelling, since all the distros are backporting
patches.  The only question is how *many* commits release has an
individual distribution taken.


By the way, in the case of the csum_seed feature, it's pretty
straightforward to just run "tune2fs -O ^metadata_csum_seed
/tmp/boot.img".  If the UUID has been changed since the file system
was created, you'll have to do this while the file system is unmounted
and it will take a few seconds, but that's almost certainly not the
case with vmdb2.

	       	      	       	       - Ted