Re: [PATCH v4 16/27] xfs: add parent attributes to link

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

On Fri, Oct 21, 2022 at 03:29:25PM -0700, allison.henderson@oracle.com wrote:
> From: Allison Henderson <allison.henderson@oracle.com>
> 
> This patch modifies xfs_link to add a parent pointer to the inode.
> 
> Signed-off-by: Dave Chinner <dchinner@redhat.com>
> Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
> ---
>  fs/xfs/xfs_inode.c | 60 ++++++++++++++++++++++++++++++++++++++--------
>  1 file changed, 50 insertions(+), 10 deletions(-)
> 
> diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
> index ae6604f51ce8..f2e7da1befa4 100644
> --- a/fs/xfs/xfs_inode.c
> +++ b/fs/xfs/xfs_inode.c
> @@ -1248,16 +1248,32 @@ xfs_create_tmpfile(
>  	return error;
>  }
>  
> +unsigned int
> +xfs_link_space_res(
> +	struct xfs_mount	*mp,
> +	unsigned int		namelen)
> +{
> +	unsigned int		ret;
> +
> +	ret = XFS_DIRENTER_SPACE_RES(mp, namelen);
> +	if (xfs_has_parent(mp))
> +		ret += xfs_pptr_calc_space_res(mp, namelen);
> +
> +	return ret;
> +}
> +
>  int
>  xfs_link(
> -	xfs_inode_t		*tdp,
> -	xfs_inode_t		*sip,
> +	struct xfs_inode	*tdp,
> +	struct xfs_inode	*sip,
>  	struct xfs_name		*target_name)
>  {
> -	xfs_mount_t		*mp = tdp->i_mount;
> -	xfs_trans_t		*tp;
> +	struct xfs_mount	*mp = tdp->i_mount;
> +	struct xfs_trans	*tp;
>  	int			error, nospace_error = 0;
>  	int			resblks;
> +	xfs_dir2_dataptr_t	diroffset;
> +	struct xfs_parent_defer	*parent = NULL;
>  
>  	trace_xfs_link(tdp, target_name);
>  
> @@ -1274,11 +1290,17 @@ xfs_link(
>  	if (error)
>  		goto std_return;
>  
> -	resblks = XFS_LINK_SPACE_RES(mp, target_name->len);
> +	if (xfs_has_parent(mp)) {
> +		error = xfs_parent_init(mp, &parent);
> +		if (error)
> +			goto std_return;
> +	}
> +
> +	resblks = xfs_link_space_res(mp, target_name->len);
>  	error = xfs_trans_alloc_dir(tdp, &M_RES(mp)->tr_link, sip, &resblks,
>  			&tp, &nospace_error);
>  	if (error)
> -		goto std_return;
> +		goto drop_incompat;
>  
>  	/*
>  	 * If we are using project inheritance, we only allow hard link
> @@ -1311,14 +1333,27 @@ xfs_link(
>  	}
>  
>  	error = xfs_dir_createname(tp, tdp, target_name, sip->i_ino,
> -				   resblks, NULL);
> +				   resblks, &diroffset);
>  	if (error)
> -		goto error_return;
> +		goto out_defer_cancel;
>  	xfs_trans_ichgtime(tp, tdp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
>  	xfs_trans_log_inode(tp, tdp, XFS_ILOG_CORE);
>  
>  	xfs_bumplink(tp, sip);
>  
> +	/*
> +	 * If we have parent pointers, we now need to add the parent record to
> +	 * the attribute fork of the inode. If this is the initial parent
> +	 * attribute, we need to create it correctly, otherwise we can just add
> +	 * the parent to the inode.
> +	 */
> +	if (parent) {
> +		error = xfs_parent_defer_add(tp, parent, tdp, target_name,
> +					     diroffset, sip);
> +		if (error)
> +			goto out_defer_cancel;
> +	}
> +
>  	/*
>  	 * If this is a synchronous mount, make sure that the
>  	 * link transaction goes to disk before returning to
> @@ -1332,11 +1367,16 @@ xfs_link(
>  	xfs_iunlock(sip, XFS_ILOCK_EXCL);
>  	return error;
>  
> - error_return:
> +out_defer_cancel:
> +	xfs_defer_cancel(tp);
> +error_return:
>  	xfs_trans_cancel(tp);

It's no longer necessary to call xfs_defer_cancel before
xfs_trans_cancel, so you can eliminate this cleanup code.

With that fixed,
Reviewed-by: Darrick J. Wong <djwong@kernel.org>

--D


>  	xfs_iunlock(tdp, XFS_ILOCK_EXCL);
>  	xfs_iunlock(sip, XFS_ILOCK_EXCL);
> - std_return:
> +drop_incompat:
> +	if (parent)
> +		xfs_parent_cancel(mp, parent);
> +std_return:
>  	if (error == -ENOSPC && nospace_error)
>  		error = nospace_error;
>  	return error;
> -- 
> 2.25.1
>