Re: [PATCH] xfs: reinstate the old i_version counter as STATX_CHANGE_COOKIE

[Jeff Layton <jlayton@kernel.org>]

On Fri, 2023-09-29 at 14:43 -0400, Jeff Layton wrote:
> The handling of STATX_CHANGE_COOKIE was moved into generic_fillattr in
> commit 0d72b92883c6 (fs: pass the request_mask to generic_fillattr), but
> we didn't account for the fact that xfs doesn't call generic_fillattr at
> all.
> 
> Make XFS report its i_version as the STATX_CHANGE_COOKIE.
> 
> Fixes: 0d72b92883c6 (fs: pass the request_mask to generic_fillattr)
> Signed-off-by: Jeff Layton <jlayton@kernel.org>
> ---
> I had hoped to fix this in a better way with the multigrain patches, but
> it's taking longer than expected (if it even pans out at this point).
> 
> Until then, make sure we use XFS's i_version as the STATX_CHANGE_COOKIE,
> even if it's bumped due to atime updates. Too many invalidations is
> preferable to not enough.
> ---
>  fs/xfs/xfs_iops.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
> index 1c1e6171209d..2b3b05c28e9e 100644
> --- a/fs/xfs/xfs_iops.c
> +++ b/fs/xfs/xfs_iops.c
> @@ -584,6 +584,11 @@ xfs_vn_getattr(
>  		}
>  	}
>  
> +	if ((request_mask & STATX_CHANGE_COOKIE) && IS_I_VERSION(inode)) {
> +		stat->change_cookie = inode_query_iversion(inode);
> +		stat->result_mask |= STATX_CHANGE_COOKIE;
> +	}
> +
>  	/*
>  	 * Note: If you add another clause to set an attribute flag, please
>  	 * update attributes_mask below.
> 
> ---
> base-commit: df964ce9ef9fea10cf131bf6bad8658fde7956f6
> change-id: 20230929-xfs-iversion-819fa2c18591
> 
> Best regards,

Ping?

This patch is needed in v6.6 to prevent a regression when serving XFS
via NFSD. I'd prefer this go in via the xfs tree, but let me know if
you need me to get this merged this via a different one.

Thanks,
-- 
Jeff Layton <jlayton@kernel.org>