Re: Issues with md raid 1 on kernel 6.18 after booting kernel 6.19-rc1 once

Hi,

在 2025/12/17 15:33, Paul Menzel 写道:
> Dear Kuai,
>
>
> Am 17.12.25 um 08:17 schrieb Yu Kuai:
>
>> 在 2025/12/17 15:13, BugReports 写道:
>>>
>>> ...
>>>
>>> We'll have to backport following patch into old kernels to make
>>> new arrays to assemble in old kernels. ....
>>>
>>> The md array which i am talking about was not created with kernel 
>>> 6.19, it was created sometime in 2024.
>>>
>>> It was just used in kernel 6.19 and that broke compatibility with
>>> my 6.18 kernel.
>>
>> I know, I mean any array that is created or assembled in new kernels
>> will now have lsb field stored in metadata. This field is not
>> defined in old kernels and that's why array can't assembled in old
>> kernels, due to unknown metadata.
>>
>> This is what we have to do for new features, and we're planning to
>> avoid the forward compatibility issue with the above patch that I
>> mentioned.
> Is there really no way around it? Just testing a new kernel and being 
> able to go back must be supported in my opinion, at least between one 
> or two LTS versions.

As I said, following patch should be backported to LTS kernels to avoid the problem.

https://lore.kernel.org/linux-raid/[email protected]

>
>
> Kind regards,
>
> Paul

-- 
Thansk,
Kuai