Re: [PATCH] xfs: check da node block pad field during scrub

[Darrick J. Wong]

On Sat, Apr 04, 2026 at 03:30:44PM +0100, Yuto Ohnuki wrote:
> The da node block header (xfs_da3_node_hdr) contains a __pad32 field
> that should always be zero. Add a check for this during directory and
> attribute btree scrubbing so that non-zero padding is flagged as
> corruption.
> 
> Signed-off-by: Yuto Ohnuki <ytohnuki@xxxxxxxxxx>
> ---
>  fs/xfs/scrub/dabtree.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/xfs/scrub/dabtree.c b/fs/xfs/scrub/dabtree.c
> index 1a71d36898b1..73d5a3bd936a 100644
> --- a/fs/xfs/scrub/dabtree.c
> +++ b/fs/xfs/scrub/dabtree.c
> @@ -454,7 +454,12 @@ xchk_da_btree_block(
>  			}
>  		}
>  
> -		/* XXX: Check hdr3.pad32 once we know how to fix it. */

Same question as the previous patch -- does xfs_da3_node_create actually
zero out the pad field?

> +		if (xfs_has_crc(ip->i_mount)) {
> +			struct xfs_da3_node_hdr *nodehdr3 = blk->bp->b_addr;
> +
> +			if (be32_to_cpu(nodehdr3->__pad32) != 0)
> +				xchk_da_set_corrupt(ds, level);

and same comment about how you can only set xchk_da_set_preen if old
kernels were ok with nonzero __pad32.

--D

> +		}
>  		break;
>  	default:
>  		xchk_da_set_corrupt(ds, level);
> -- 
> 2.50.1
> 
> 
> 
> 
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