Re: [PATCH 2/2] xfs: check da node magic in _node_lookup_int

[Brian Foster <bfoster@redhat.com>]

On Tue, Jul 31, 2018 at 04:21:00PM -0700, Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@oracle.com>
> 
> Before we start processing what we /think/ is a da3 node block, actually
> check the magic to make sure that we're looking at a node block.  This
> way we won't blow the asserts in _node_hdr_from_disk on corrupted
> metadata.
> 
> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> ---

Reviewed-by: Brian Foster <bfoster@redhat.com>

>  fs/xfs/libxfs/xfs_da_btree.c |    4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> 
> diff --git a/fs/xfs/libxfs/xfs_da_btree.c b/fs/xfs/libxfs/xfs_da_btree.c
> index 8ffe17b223da..376bee94b5dd 100644
> --- a/fs/xfs/libxfs/xfs_da_btree.c
> +++ b/fs/xfs/libxfs/xfs_da_btree.c
> @@ -1523,8 +1523,10 @@ xfs_da3_node_lookup_int(
>  			break;
>  		}
>  
> -		blk->magic = XFS_DA_NODE_MAGIC;
> +		if (magic != XFS_DA_NODE_MAGIC && magic != XFS_DA3_NODE_MAGIC)
> +			return -EFSCORRUPTED;
>  
> +		blk->magic = XFS_DA_NODE_MAGIC;
>  
>  		/*
>  		 * Search an intermediate node for a match.
> 
> --
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