Re: [PATCH v2] xfs: don't bump the i_version on an atime update in xfs_vn_update_time

Dave Chinner
2022-08-22T23:34:46Z

On Mon, Aug 22, 2022 at 09:40:11AM -0400, Jeff Layton wrote:
> xfs will update the i_version when updating only the atime value, which
> is not desirable for any of the current consumers of i_version. Doing so
> leads to unnecessary cache invalidations on NFS and extra measurement
> activity in IMA.
>
> Add a new XFS_ILOG_NOIVER flag, and use that to indicate that the
> transaction should not update the i_version. Set that value in
> xfs_vn_update_time if we're only updating the atime.
>
> Cc: Dave Chinner <david@fromorbit.com>
> Cc: NeilBrown <neilb@suse.de>
> Cc: Trond Myklebust <trondmy@hammerspace.com>
> Cc: David Wysochanski <dwysocha@redhat.com>
> Signed-off-by: Jeff Layton <jlayton@kernel.org>

NACK.

We need to define exactly what iversion covers first before we go
changing how filesystems update it. We only want to change iversion
behaviour once, and we want it done right the first time.

-Dave.
--
Dave Chinner
david@fromorbit.com