Re: [PATCH v3 3/3] md/raid1: check array size before reshape

[Yu Kuai <yukuai1@huaweicloud.com>]

Hi,

在 2023/07/31 11:48, Xueshi Hu 写道:
>> Well... I just said reshape can continue is not possible for raid1, and
>> this patch will cause that recovery can't continue is some cases.

> I see. I will reread the relevant code to gain a better understanding of
> "some cases".

It's not that complex at all, the key point is whether your changes
introduce functional changes, if so, does the effect fully evaluated.

In this case, raid1_reshape(all the callers) will set
MD_RECOVERY_RECOVER and MD_RECOVERY_NEEDED to indicate that daemon
thread must check if recovery is needed, if so it will start recovery.

I agree that recovery is probably not needed in this case that
raid_disks is the same, however, note that recovery can be interrupted
by user, and raid1_reshape() can be triggered by user as well, this
means following procedures will end up different:

1. trigger a recovery;
2. interupt the recovery;
3. trigger a raid1_reshape();

Before this patch, the interupted recovery will continue;

This is minor, but I can't say that no user will be affected, and I
really prefer to keep this behaviour, which means this patch can just do
some cleanup without introducing functional changes.

Thanks,
Kuai