Re: [PATCH 1/3] xfs: mark dir corrupt when lookup-by-hash fails

[Dave Chinner <david@fromorbit.com>]

On Fri, Feb 28, 2020 at 05:49:09PM -0800, Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@oracle.com>
> 
> In xchk_dir_actor, we attempt to validate the directory hash structures
> by performing a directory entry lookup by (hashed) name.  If the lookup
> returns ENOENT, that means that the hash information is corrupt.  The
> _process_error functions don't catch this, so we have to add that
> explicitly.
> 
> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> ---
>  fs/xfs/scrub/dir.c |    5 +++++
>  1 file changed, 5 insertions(+)
> 
> 
> diff --git a/fs/xfs/scrub/dir.c b/fs/xfs/scrub/dir.c
> index 266da4e4bde6..54afa75c95d1 100644
> --- a/fs/xfs/scrub/dir.c
> +++ b/fs/xfs/scrub/dir.c
> @@ -155,6 +155,11 @@ xchk_dir_actor(
>  	xname.type = XFS_DIR3_FT_UNKNOWN;
>  
>  	error = xfs_dir_lookup(sdc->sc->tp, ip, &xname, &lookup_ino, NULL);
> +	if (error == -ENOENT) {
> +		/* ENOENT means the hash lookup failed and the dir is corrupt */
> +		xchk_fblock_set_corrupt(sdc->sc, XFS_DATA_FORK, offset);
> +		return -EFSCORRUPTED;
> +	}
>  	if (!xchk_fblock_process_error(sdc->sc, XFS_DATA_FORK, offset,
>  			&error))
>  		goto out;

So why is this error handling open coded rather than doing something
like this to use the generic, pre-existing corruption handling:

	if (error == -ENOENT) {
		/* ENOENT means the hash lookup failed and the dir is corrupt */
		error = -EFSCORRUPTED;
	}
	if (!xchk_fblock_process_error(sdc->sc, XFS_DATA_FORK, offset,
			&error))
		goto out;

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com