# Re: \[PATCH\] super1: make write\_bitmap1 compatible with previous mdadm versions

- From: Jes Sorensen \<hidden\>
- Date: 2016-10-19 15:21:31 
- List: linux-raid
- Page: https://ratatoskr.run/linux-raid/2016/10/6633127
- Thread: https://ratatoskr.run/linux-raid/2016/10/6633127/t.md

```text
Guoqing Jiang [ref] writes:
> For older mdadm version, v1.x metadata has different bitmap_offset,
> we can't ensure all the bitmaps are on a 4K boundary since writing
> 4K for bitmap could corrupt the superblock, and Anthony reported
> the bug about it at below link.
>
> https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=837964
>
> So let's check about the alignment for bitmap_offset before set
> the boundary to 4096 unconditionally. Thanks for Neil's detailed
> explanation.
>
> Reported-by: Anthony DeRobertis <redacted>
> Fixes: 95a05b37e8eb ("Create n bitmaps for clustered mode")
> Cc: Neil Brown <redacted>
> Signed-off-by: Guoqing Jiang <redacted>
> ---
>  super1.c | 10 +++++++++-
>  1 file changed, 9 insertions(+), 1 deletion(-)

Applied!

Thanks,
Jes
```