Re: [PATCH] mkfs: warn about V4 deprecation when creating new V4 filesystems

["Darrick J. Wong" <djwong@kernel.org>]

On Tue, Aug 31, 2021 at 04:33:00PM -0700, Darrick J. Wong wrote:
> On Wed, Sep 01, 2021 at 09:29:27AM +1000, Dave Chinner wrote:
> > On Tue, Aug 31, 2021 at 03:44:38PM -0700, Darrick J. Wong wrote:
> > > From: Darrick J. Wong <djwong@kernel.org>
> > > 
> > > The V4 filesystem format is deprecated in the upstream Linux kernel.  In
> > > September 2025 it will be turned off by default in the kernel and five
> > > years after that, support will be removed entirely.  Warn people
> > > formatting new filesystems with the old format, particularly since V4 is
> > > not the default.
> > > 
> > > Signed-off-by: Darrick J. Wong <djwong@kernel.org>
> > > ---
> > >  mkfs/xfs_mkfs.c |    9 +++++++++
> > >  1 file changed, 9 insertions(+)
> > > 
> > > diff --git a/mkfs/xfs_mkfs.c b/mkfs/xfs_mkfs.c
> > > index 53904677..b8c11ce9 100644
> > > --- a/mkfs/xfs_mkfs.c
> > > +++ b/mkfs/xfs_mkfs.c
> > > @@ -2103,6 +2103,15 @@ _("Directory ftype field always enabled on CRC enabled filesystems\n"));
> > >  		}
> > >  
> > >  	} else {	/* !crcs_enabled */
> > > +		/*
> > > +		 * The V4 filesystem format is deprecated in the upstream Linux
> > > +		 * kernel.  In September 2025 it will be turned off by default
> > > +		 * in the kernel and in September 2030 support will be removed
> > > +		 * entirely.
> > > +		 */
> > > +		fprintf(stdout,
> > > +_("V4 filesystems are deprecated and will not be supported by future versions.\n"));
> > > +
> > >  		/*
> > >  		 * The kernel doesn't support crc=0,finobt=1 filesystems.
> > >  		 * If crcs are not enabled and the user has not explicitly
> > > 
> > 
> > Looks good to me.
> > 
> > Reviewed-by: Dave Chinner <dchinner@redhat.com>
> > 
> > Do we need to update the mkfs filter in fstests now?
> 
> AFAICT, no, because (so far) the only fstests that care about mkfs
> output only look for messages on stderr, and dump stdout to $seqres.full
> or /dev/null.

So I'll immediately put my foot in my mouth; there /was/ a patch in my
fstests tree to fix the one test that broke: xfs/449.

--D

> --D
> 
> > Cheers,
> > 
> > Dave.
> > -- 
> > Dave Chinner
> > david@fromorbit.com