Re: [PATCH 1/1] mdadm/bitmap: locate bitmap calcuate bitmap position wrongly

[Jes Sorensen <jes@trained-monkey.org>]

On 10/30/20 2:44 AM, heming.zhao@suse.com wrote:
> You are right. Only cluster case can trigger your patch code.
> Hardcode 4096 is correct.

Just catching up, was the conclusion the original patch was correct?

Thanks,
Jes


> On 10/30/20 1:53 PM, Xiao Ni wrote:
>> Hi Heming
>>
>> The cluster raid is only supported by super 1.2, so we don't need to consider the old system when
>> it's a cluster raid.
>>
>> Regards
>> Xiao
>>
>> On 10/28/2020 08:29 PM, heming.zhao@suse.com wrote:
>>> Hello Xiao,
>>>
>>> My review comment:
>>> You code only work in modern system. the boundary is 4k not 512, because using hardcode 4k to call calc_bitmap_size
>>>
>>> In current cluster env, if bitmap area beyond 4K size (or 512 in very old system), locate_bitmap1
>>> will return wrong address.
>>>
>>> Please refer write_bitmap1() to saparate 512 & 4096 case.
>>>
>>> On 10/28/20 2:04 PM, Xiao Ni wrote:
>>>> Now it only adds bitmap offset based on cluster nodes. It's not right. It needs to
>>>> add per node bitmap space to find next node bitmap position.
>>>>
>>>> Signed-off-by: Xiao Ni <xni@redhat.com>
>>>> ---
>>>>    super1.c | 12 +++++++++---
>>>>    1 file changed, 9 insertions(+), 3 deletions(-)
>>>>
>>>> diff --git a/super1.c b/super1.c
>>>> index 8b0d6ff..b5b379b 100644
>>>> --- a/super1.c
>>>> +++ b/super1.c
>>>> @@ -2582,8 +2582,9 @@ add_internal_bitmap1(struct supertype *st,
>>>>    static int locate_bitmap1(struct supertype *st, int fd, int node_num)
>>>>    {
>>>> -    unsigned long long offset;
>>>> +    unsigned long long offset, bm_sectors_per_node;
>>>>        struct mdp_superblock_1 *sb;
>>>> +    bitmap_super_t *bms;
>>>>        int mustfree = 0;
>>>>        int ret;
>>>> @@ -2598,8 +2599,13 @@ static int locate_bitmap1(struct supertype *st, int fd, int node_num)
>>>>            ret = 0;
>>>>        else
>>>>            ret = -1;
>>>> -    offset = __le64_to_cpu(sb->super_offset);
>>>> -    offset += (int32_t) __le32_to_cpu(sb->bitmap_offset) * (node_num + 1);
>>>> +
>>>> +    offset = __le64_to_cpu(sb->super_offset) + __le32_to_cpu(sb->bitmap_offset);
>>>> +    if (node_num) {
>>>> +        bms = (bitmap_super_t*)(((char*)sb)+MAX_SB_SIZE);
>>>> +        bm_sectors_per_node = calc_bitmap_size(bms, 4096) >> 9;
>>>> +        offset += bm_sectors_per_node * node_num;
>>>> +    }
>>>>        if (mustfree)
>>>>            free(sb);
>>>>        lseek64(fd, offset<<9, 0);
>>>>
>>
>