[PATCH v3] erofs: use Z_EROFS_LCLUSTER_TYPE_MAX to simplify switches

[Gao Xiang]

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 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.

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