[PATCH] erofs: do sanity check on m->type in z_erofs_load_compact_lcluster()

[Gao Xiang]

On 2025/7/8 10:30, Hongbo Li wrote:
> 
> 
> On 2025/7/7 16:47, Chao Yu wrote:
>> All below functions will do sanity check on m->type, let's move sanity
>> check to z_erofs_load_compact_lcluster() for cleanup.
>> - z_erofs_map_blocks_fo
>> - z_erofs_get_extent_compressedlen
>> - z_erofs_get_extent_decompressedlen
>> - z_erofs_extent_lookback
>>
>> Signed-off-by: Chao Yu <chao at kernel.org>
>> ---
>>   fs/erofs/zmap.c | 60 ++++++++++++++++++-------------------------------
>>   1 file changed, 22 insertions(+), 38 deletions(-)
>>
>> diff --git a/fs/erofs/zmap.c b/fs/erofs/zmap.c
>> index 0bebc6e3a4d7..e530b152e14e 100644
>> --- a/fs/erofs/zmap.c
>> +++ b/fs/erofs/zmap.c
>> @@ -240,6 +240,13 @@ static int z_erofs_load_compact_lcluster(struct z_erofs_maprecorder *m,
>>   static int z_erofs_load_lcluster_from_disk(struct z_erofs_maprecorder *m,
>>                          unsigned int lcn, bool lookahead)
>>   {
>> +    if (m->type >= Z_EROFS_LCLUSTER_TYPE_MAX) {
>> +        erofs_err(m->inode->i_sb, "unknown type %u @ lcn %u of nid %llu",
>> +                m->type, lcn, EROFS_I(m->inode)->nid);
>> +        DBG_BUGON(1);
>> +        return -EOPNOTSUPP;
>> +    }
>> +
> 
> Hi, Chao,
> 
> After moving the condition in here, there is no need to check in z_erofs_extent_lookback, z_erofs_get_extent_compressedlen and z_erofs_get_extent_decompressedlen. Because in z_erofs_map_blocks_fo, the condition has been checked in before. Right?

I've replied some similar question.

Because z_erofs_get_extent_compressedlen and z_erofs_get_extent_decompressedlen()
use the different lcn (lcluster) against z_erofs_map_blocks_fo().

So if a new lcn(lcluster number) is loaded, we'd check if the type is valid.

Thanks,
Gao Xiang