Re: [PATCH v3] erofs: use Z_EROFS_LCLUSTER_TYPE_MAX to simplify switches

[Hongzhen Luo <hongzhen@linux.alibaba.com>]

On 2025/2/10 10:59, Gao Xiang wrote:
>
>
> On 2025/2/7 17:14, Gao Xiang wrote:
>>
>>
>> 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@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.
>
> Sorry, I was wrong.  I was missing the part of the end of
> function, how about the following diff?
>
> diff --git a/fs/erofs/zmap.c b/fs/erofs/zmap.c
> index 7dba1573498b..d278ebd60281 100644
> --- a/fs/erofs/zmap.c
> +++ b/fs/erofs/zmap.c
> @@ -273,7 +273,7 @@ static int z_erofs_extent_lookback(struct 
> z_erofs_maprecorder *m,
>                 } else if (m->type == Z_EROFS_LCLUSTER_TYPE_NONHEAD) {
>                         lookback_distance = m->delta[0];
>                         if (!lookback_distance)
> -                               goto err_bogus;
> +                               break;
>                         continue;
>                 } else {
>                         m->headtype = m->type;
> @@ -281,7 +281,6 @@ static int z_erofs_extent_lookback(struct 
> z_erofs_maprecorder *m,
>                         return 0;
>                 }
>         }
> -err_bogus:
>         erofs_err(sb, "bogus lookback distance %u @ lcn %lu of nid %llu",
>                   lookback_distance, m->lcn, vi->nid);
>         DBG_BUGON(1);
>
> Thanks,
> Gao Xiang

Sure, I will send an updated version later.

Thanks,
Hongzhen Luo