Re: [PATCH 11/12] xfs: remove the special COW fork handling in xfs_bmapi_read

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

On Fri, May 08, 2020 at 08:34:22AM +0200, Christoph Hellwig wrote:
> We don't call xfs_bmapi_read for the COW fork anymore, so remove the
> special casing.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> Reviewed-by: Brian Foster <bfoster@redhat.com>

I was surprised this assertion, but apparently it's true, even in my dev
tree, so:
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>

--D

> ---
>  fs/xfs/libxfs/xfs_bmap.c | 13 +------------
>  1 file changed, 1 insertion(+), 12 deletions(-)
> 
> diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
> index fda13cd7add0e..76be1a18e2442 100644
> --- a/fs/xfs/libxfs/xfs_bmap.c
> +++ b/fs/xfs/libxfs/xfs_bmap.c
> @@ -3902,8 +3902,7 @@ xfs_bmapi_read(
>  	int			whichfork = xfs_bmapi_whichfork(flags);
>  
>  	ASSERT(*nmap >= 1);
> -	ASSERT(!(flags & ~(XFS_BMAPI_ATTRFORK|XFS_BMAPI_ENTIRE|
> -			   XFS_BMAPI_COWFORK)));
> +	ASSERT(!(flags & ~(XFS_BMAPI_ATTRFORK | XFS_BMAPI_ENTIRE)));
>  	ASSERT(xfs_isilocked(ip, XFS_ILOCK_SHARED|XFS_ILOCK_EXCL));
>  
>  	if (XFS_IS_CORRUPT(mp, !xfs_ifork_has_extents(ip, whichfork)) ||
> @@ -3918,16 +3917,6 @@ xfs_bmapi_read(
>  
>  	ifp = XFS_IFORK_PTR(ip, whichfork);
>  	if (!ifp) {
> -		/* No CoW fork?  Return a hole. */
> -		if (whichfork == XFS_COW_FORK) {
> -			mval->br_startoff = bno;
> -			mval->br_startblock = HOLESTARTBLOCK;
> -			mval->br_blockcount = len;
> -			mval->br_state = XFS_EXT_NORM;
> -			*nmap = 1;
> -			return 0;
> -		}
> -
>  		/*
>  		 * A missing attr ifork implies that the inode says we're in
>  		 * extents or btree format but failed to pass the inode fork
> -- 
> 2.26.2
>