Re: [PATCH v2] xfs: update ctime and mtime on clone destinatation inodes

["Darrick J. Wong" <darrick.wong@oracle.com>]

[cc amir since he piped up about the v1 patch]

On Fri, Feb 03, 2017 at 10:57:15AM +0100, Christoph Hellwig wrote:
> We're changing both metadata and data, so we need to update the
> timestamps for clone operations.  Dedupe on the other hand does
> not change file data, and only changes invisible metadata so the
> timestamps should not be updated.
> 
> This follows existing btrfs behavior.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>  fs/xfs/xfs_reflink.c | 13 ++++++++++---
>  1 file changed, 10 insertions(+), 3 deletions(-)
> 
> diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c
> index d5a2cf2b469b..199ce0100bc6 100644
> --- a/fs/xfs/xfs_reflink.c
> +++ b/fs/xfs/xfs_reflink.c
> @@ -961,13 +961,15 @@ STATIC int
>  xfs_reflink_update_dest(
>  	struct xfs_inode	*dest,
>  	xfs_off_t		newlen,
> -	xfs_extlen_t		cowextsize)
> +	xfs_extlen_t		cowextsize,
> +	bool			is_dedupe)
>  {
>  	struct xfs_mount	*mp = dest->i_mount;
>  	struct xfs_trans	*tp;
>  	int			error;
>  
> -	if (newlen <= i_size_read(VFS_I(dest)) && cowextsize == 0)
> +	if (is_dedupe &&
> +	    newlen <= i_size_read(VFS_I(dest)) && cowextsize == 0 && is_dedupe)
>  		return 0;

Redundant is_dedupe tests here.

I also wonder if we really /want/ to emulate the existing btrfs
behavior, which seems to be:

reflink: update mtime & ctime
dedupe: do not update mtime or ctime

In particular, dedupe changes the inode metadata, which should qualify
for a ctime update, right?

--D

>  	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_ichange, 0, 0, 0, &tp);
> @@ -988,6 +990,10 @@ xfs_reflink_update_dest(
>  		dest->i_d.di_flags2 |= XFS_DIFLAG2_COWEXTSIZE;
>  	}
>  
> +	if (!is_dedupe) {
> +		xfs_trans_ichgtime(tp, dest,
> +				   XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
> +	}
>  	xfs_trans_log_inode(tp, dest, XFS_ILOG_CORE);
>  
>  	error = xfs_trans_commit(tp);
> @@ -1301,7 +1307,8 @@ xfs_reflink_remap_range(
>  	    !(dest->i_d.di_flags2 & XFS_DIFLAG2_COWEXTSIZE))
>  		cowextsize = src->i_d.di_cowextsize;
>  
> -	ret = xfs_reflink_update_dest(dest, pos_out + len, cowextsize);
> +	ret = xfs_reflink_update_dest(dest, pos_out + len, cowextsize,
> +			is_dedupe);
>  
>  out_unlock:
>  	xfs_iunlock(src, XFS_MMAPLOCK_EXCL);
> -- 
> 2.11.0
> 
> --
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