Re: [PATCH v5 6/8] xfs: switch to multigrain timestamps

Dave Chinner
2023-07-19T01:35:48Z

On Thu, Jul 13, 2023 at 07:00:55PM -0400, Jeff Layton wrote:
> Enable multigrain timestamps, which should ensure that there is an
> apparent change to the timestamp whenever it has been written after
> being actively observed via getattr.
>
> Also, anytime the mtime changes, the ctime must also change, and those
> are now the only two options for xfs_trans_ichgtime. Have that function
> unconditionally bump the ctime, and warn if XFS_ICHGTIME_CHG is ever not
> set.
>
> Signed-off-by: Jeff Layton <jlayton@kernel.org>
> ---
> fs/xfs/libxfs/xfs_trans_inode.c | 6 +++---
> fs/xfs/xfs_iops.c | 4 ++--
> fs/xfs/xfs_super.c | 2 +-
> 3 files changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/fs/xfs/libxfs/xfs_trans_inode.c b/fs/xfs/libxfs/xfs_trans_inode.c
> index 0c9df8df6d4a..86f5ffce2d89 100644
> --- a/fs/xfs/libxfs/xfs_trans_inode.c
> +++ b/fs/xfs/libxfs/xfs_trans_inode.c
> @@ -62,12 +62,12 @@ xfs_trans_ichgtime(
> ASSERT(tp);
> ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
>
> - tv = current_time(inode);
> + /* If the mtime changes, then ctime must also change */
> + WARN_ON_ONCE(!(flags & XFS_ICHGTIME_CHG));

Make that an ASSERT(flags & XFS_ICHGTIME_CHG), please. There's no
need to verify this at runtime on production kernels.

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