Re: [PATCH 10/10] xfs: punch delalloc extents from the COW fork for COW writes

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

On Tue, Aug 27, 2024 at 07:09:57AM +0200, Christoph Hellwig wrote:
> When ->iomap_end is called on a short write to the COW fork it needs to
> punch stale delalloc data from the COW fork and not the data fork.
> 
> Ensure that IOMAP_F_NEW is set for new COW fork allocations in
> xfs_buffered_write_iomap_begin, and then use the IOMAP_F_SHARED flag
> in xfs_buffered_write_delalloc_punch to decide which fork to punch.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Looks fine,
Reviewed-by: Darrick J. Wong <djwong@kernel.org>

--D

> ---
>  fs/xfs/xfs_iomap.c | 8 +++++---
>  1 file changed, 5 insertions(+), 3 deletions(-)
> 
> diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
> index 22e9613a995f12..4113e09cb836a8 100644
> --- a/fs/xfs/xfs_iomap.c
> +++ b/fs/xfs/xfs_iomap.c
> @@ -1195,7 +1195,7 @@ xfs_buffered_write_iomap_begin(
>  		xfs_trim_extent(&cmap, offset_fsb, imap.br_startoff - offset_fsb);
>  	}
>  
> -	iomap_flags = IOMAP_F_SHARED;
> +	iomap_flags |= IOMAP_F_SHARED;
>  	seq = xfs_iomap_inode_sequence(ip, iomap_flags);
>  	xfs_iunlock(ip, lockmode);
>  	return xfs_bmbt_to_iomap(ip, iomap, &cmap, flags, iomap_flags, seq);
> @@ -1212,8 +1212,10 @@ xfs_buffered_write_delalloc_punch(
>  	loff_t			length,
>  	struct iomap		*iomap)
>  {
> -	xfs_bmap_punch_delalloc_range(XFS_I(inode), XFS_DATA_FORK, offset,
> -			offset + length);
> +	xfs_bmap_punch_delalloc_range(XFS_I(inode),
> +			(iomap->flags & IOMAP_F_SHARED) ?
> +				XFS_COW_FORK : XFS_DATA_FORK,
> +			offset, offset + length);
>  }
>  
>  static int
> -- 
> 2.43.0
> 
>