[PATCH v3] erofs: use Z_EROFS_LCLUSTER_TYPE_MAX to simplify switches

[Gao Xiang]

On 2025/2/7 16:50, Hongzhen Luo wrote:
> There's no need to enumerate each type.  No logic changes.
> 
> Signed-off-by: Hongzhen Luo <hongzhen at linux.alibaba.com>
> ---> v3: Code cleanup, remove logically inequivalent changes.
> v2: https://lore.kernel.org/all/20250207080829.2405528-1-hongzhen@linux.alibaba.com/
> v1: https://lore.kernel.org/all/20250207064135.2249529-1-hongzhen@linux.alibaba.com/
> ---
>   fs/erofs/zmap.c | 60 +++++++++++++++++++------------------------------
>   1 file changed, 23 insertions(+), 37 deletions(-)
> 
> diff --git a/fs/erofs/zmap.c b/fs/erofs/zmap.c
> index 689437e99a5a..7dba1573498b 100644
> --- a/fs/erofs/zmap.c
> +++ b/fs/erofs/zmap.c
> @@ -265,23 +265,20 @@ static int z_erofs_extent_lookback(struct z_erofs_maprecorder *m,
>   		if (err)
>   			return err;
>   
> -		switch (m->type) {
> -		case Z_EROFS_LCLUSTER_TYPE_NONHEAD:
> +		if (m->type >= Z_EROFS_LCLUSTER_TYPE_MAX) {
> +			erofs_err(sb, "unknown type %u @ lcn %lu of nid %llu",
> +				  m->type, lcn, vi->nid);
> +			DBG_BUGON(1);
> +			return -EOPNOTSUPP;
> +		} else if (m->type == Z_EROFS_LCLUSTER_TYPE_NONHEAD) {
>   			lookback_distance = m->delta[0];
>   			if (!lookback_distance)
>   				goto err_bogus;'

Maybe just kill `goto err_bogus;` too, like:
                         if (!lookback_distance) {
                                 erofs_err(sb, "bogus lookback distance %u @ lcn %lu of nid %llu",
                                           lookback_distance, m->lcn, vi->nid);
                                 DBG_BUGON(1);
                                 return -EFSCORRUPTED;
                         }

Otherwise it looks good to me.

Thanks,
Gao Xiang