Re: libxfs: verifier should set buffer error when da block has a bad magic number

[Dave Chinner <david@xxxxxxxxxxxxx>]

On Mon, Aug 24, 2015 at 09:06:09PM -0700, Darrick J. Wong wrote:
> If xfs_da3_node_read_verify() doesn't recognize the magic number of a
> buffer it's just read, set the buffer error to -EFSCORRUPTED so that
> the error can be sent up to userspace.  Without this patch we'll
> ASSERT on the bad magic eventually while trying to traverse or change
> the block, but we really ought to fail fast in the verifier.
> 
> Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
> ---
>  fs/xfs/libxfs/xfs_da_btree.c |    1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/fs/xfs/libxfs/xfs_da_btree.c b/fs/xfs/libxfs/xfs_da_btree.c
> index 2385f8c..ec4a5a1 100644
> --- a/fs/xfs/libxfs/xfs_da_btree.c
> +++ b/fs/xfs/libxfs/xfs_da_btree.c
> @@ -238,6 +238,7 @@ xfs_da3_node_read_verify(
>  
>       /* corrupt block */
>       xfs_verifier_error(bp);
> +     xfs_buf_ioerror(bp, -EFSCORRUPTED);
>  }

That should be in the default block of the switch statement,
otherwise it will overwrite the error from the node format crc/
verifier failures....

Cheers,

Dave.
-- 
Dave Chinner
david@xxxxxxxxxxxxx