Re: [PATCH 2/4] xfs: xfs_rtbuf_get should check the bmapi_read results

[Bill O'Donnell <billodo@redhat.com>]

On Thu, May 31, 2018 at 09:33:57AM -0700, Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@oracle.com>
> 
> The xfs_rtbuf_get function should check the block mapping it gets back
> from bmapi_read.  If there are no mappings or the mapping isn't a real
> extent, we should return -EFSCORRUPTED rather than trying to read a
> garbage value.  We also require realtime bitmap blocks to be real,
> written allocations.
> 
> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
looks fine...
Reviewed-by: Bill O'Donnell <billodo@redhat.com>

> ---
>  fs/xfs/libxfs/xfs_rtbitmap.c |    3 +++
>  1 file changed, 3 insertions(+)
> 
> 
> diff --git a/fs/xfs/libxfs/xfs_rtbitmap.c b/fs/xfs/libxfs/xfs_rtbitmap.c
> index 106be2d0bb88..7712f282d172 100644
> --- a/fs/xfs/libxfs/xfs_rtbitmap.c
> +++ b/fs/xfs/libxfs/xfs_rtbitmap.c
> @@ -90,6 +90,9 @@ xfs_rtbuf_get(
>  	if (error)
>  		return error;
>  
> +	if (nmap == 0 || !xfs_bmap_is_real_extent(&map))
> +		return -EFSCORRUPTED;
> +
>  	ASSERT(map.br_startblock != NULLFSBLOCK);
>  	error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp,
>  				   XFS_FSB_TO_DADDR(mp, map.br_startblock),
> 
> --
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