Re: [PATCH] md: change bitmap offset verification in write_sb_page

["Radtke, Jakub" <jakub.radtke@linux.intel.com>]

Please ignore the patch.
I see that the calculation is working for the other metadata formats too.
The problem was related to my environment, and I misinterpret the 
calculation in write_sb_page, which correctly reports the error.
> On Tue, Jan 5, 2021 at 7:06 AM Jakub Radtke
> <jakub.radtke@linux.intel.com> wrote:
>> From: Jakub Radtke <jakub.radtke@intel.com>
>>
>> Removes the code that is correct only for the native metadata.
>> Write-intent bitmap support for the other metadata formats is blocked.
>>
>> rdev->sb_start is used in the calculations.
>> The sb_start is only set and used for native metadata format, and
>> the bitmap offset check will always fail if it is not set.
> Can we use different logic for native and other metadata, so that we can
> keep the check for native metadata? Maybe we can use the combination
> of mddev->major_version, mddev->minor_version, and rdev->sb_start?
>
> Thanks,
> Song
>
>> In the case of external metadata, the bitmap can be placed in various
>> places e.g. like the PPL between two volumes (the boundary checks are
>> performed on the sysfs level and in the mdadm).
>>
>> Signed-off-by: Jakub Radtke <jakub.radtke@linux.intel.com>
>> ---
>>   drivers/md/md-bitmap.c | 8 --------
>>   1 file changed, 8 deletions(-)
>>
>> diff --git a/drivers/md/md-bitmap.c b/drivers/md/md-bitmap.c
>> index 200c5d0f08bf..a78b15df4d82 100644
>> --- a/drivers/md/md-bitmap.c
>> +++ b/drivers/md/md-bitmap.c
>> @@ -236,14 +236,6 @@ static int write_sb_page(struct bitmap *bitmap, struct page *page, int wait)
>>                   */
>>                  if (mddev->external) {
>>                          /* Bitmap could be anywhere. */
>> -                       if (rdev->sb_start + offset + (page->index
>> -                                                      * (PAGE_SIZE/512))
>> -                           > rdev->data_offset
>> -                           &&
>> -                           rdev->sb_start + offset
>> -                           < (rdev->data_offset + mddev->dev_sectors
>> -                            + (PAGE_SIZE/512)))
>> -                               goto bad_alignment;
>>                  } else if (offset < 0) {
>>                          /* DATA  BITMAP METADATA  */
>>                          if (offset
>> --
>> 2.17.1
>>