[PATCH v7 12/13] ext4: switch to multigrain timestamps

[Christian Brauner]

> You could put it behind an EXPERIMENTAL Kconfig option so that the
> code stays in and can be used by the brave or foolish while it is
> still being refined.

Given that the discussion has now fully gone back to the drawing board
and this is a regression the honest thing to do is to revert the five
patches that introduce the infrastructure:

ffb6cf19e063 ("fs: add infrastructure for multigrain timestamps")
d48c33972916 ("tmpfs: add support for multigrain timestamps")
e44df2664746 ("xfs: switch to multigrain timestamps")
0269b585868e ("ext4: switch to multigrain timestamps")
50e9ceef1d4f ("btrfs: convert to multigrain timestamps")

The conversion to helpers and cleanups are sane and should stay and can
be used for any solution that gets built on top of it.

I'd appreciate a look at the branch here:
git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git vfs.ctime.revert

survives xfstests.