Re: [PATCH v3] xfs: deprecate the V4 format

[Dave Chinner <david@fromorbit.com>]

On Fri, Sep 11, 2020 at 09:43:11AM -0700, Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@oracle.com>
> 
> The V4 filesystem format contains known weaknesses in the on-disk format
> that make metadata verification diffiult.  In addition, the format will
> does not support dates past 2038 and will not be upgraded to do so.
> Therefore, we should start the process of retiring the old format to
> close off attack surfaces and to encourage users to migrate onto V5.
> 
> Therefore, make XFS V4 support a configurable option.  For the first
> period it will be default Y in case some distributors want to withdraw
> support early; for the second period it will be default N so that anyone
> who wishes to continue support can do so; and after that, support will
> be removed from the kernel.
> 
> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> ---
> v3: be a little more helpful about old xfsprogs and warn more loudly
> about deprecation
> v2: define what is a V4 filesystem, update the administrator guide
> ---
>  Documentation/admin-guide/xfs.rst |   23 +++++++++++++++++++++++
>  fs/xfs/Kconfig                    |   24 ++++++++++++++++++++++++
>  fs/xfs/xfs_super.c                |   13 +++++++++++++
>  3 files changed, 60 insertions(+)

I agree with the overall policy direction and that we should be
warning v4 filesystem users as early as possible.

Reviewed-by: Dave Chinner <dchinner@redhat.com>

-- 
Dave Chinner
david@fromorbit.com