linux-kernel - Re: [PATCH 3/4] md: fix is_mddev

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <42cbe72e-1db5-1723-789d-a93b5dc95f8f@huaweicloud.com>
Date: Wed, 16 Apr 2025 15:42:05 +0800
From: Yu Kuai <yukuai1@...weicloud.com>
To: Xiao Ni <xni@...hat.com>, Yu Kuai <yukuai1@...weicloud.com>,
 axboe@...nel.dk, song@...nel.org
Cc: linux-block@...r.kernel.org, linux-kernel@...r.kernel.org,
 linux-raid@...r.kernel.org, yi.zhang@...wei.com, yangerkun@...wei.com,
 "yukuai (C)" <yukuai3@...wei.com>
Subject: Re: [PATCH 3/4] md: fix is_mddev_idle()

Hi,

在 2025/04/16 14:20, Xiao Ni 写道:
>> +static bool is_rdev_idle(struct md_rdev *rdev, bool init)
>> +{
>> +    unsigned long last_events = rdev->last_events;
>> +
>> +    if (!bdev_is_partition(rdev->bdev))
>> +        return true;
> 
> 
> For md array, I think is_rdev_idle is not useful. Because 
> mddev->last_events must be increased while upper ios come in and idle 
> will be set to false. For dm array, mddev->last_events can't work. So 
> is_rdev_idle is for dm array. If member disk is one partition, 
> is_rdev_idle alwasy returns true, and is_mddev_idle always return true. 
> It's a bug here. Do we need to check bdev_is_partition here?

is_rdev_idle() is not used for current array, for example:

sda1 is used for array md0, and user doesn't issue IO to md0, while
user issues IO to sda2. In this case, is_mddev_idle() still fail for
array md0 because is_rdev_idle() fail.

This is just inherited from the old behaviour.

Thanks,
Kuai

> 
> Best Regards
> 
> Xiao