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Date:   Wed, 22 Mar 2023 11:38:42 +0800
From:   Ming Lei <ming.lei@redhat.com>
To:     Yu Kuai <yukuai1@huaweicloud.com>
Cc:     jack@suse.cz, hare@suse.de, hch@infradead.org, axboe@kernel.dk,
        linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
        yi.zhang@huawei.com, yangerkun@huawei.com,
        Changhui Zhong <czhong@redhat.com>,
        "yukuai (C)" <yukuai3@huawei.com>, ming.lei@redhat.com
Subject: Re: [PATCH -next 0/2] block: fix scan partition for exclusively open
 device again
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On Wed, Mar 22, 2023 at 10:15:30AM +0800, Yu Kuai wrote:
> Hi,
> 
> 在 2023/03/22 10:02, Yu Kuai 写道:
> > Hi,
> > 
> > 在 2023/03/22 9:34, Ming Lei 写道:
> > > On Wed, Mar 22, 2023 at 09:26:07AM +0800, Yu Kuai wrote:
> > > > Hi,
> > > > 
> > > > 在 2023/03/21 19:43, Ming Lei 写道:
> > > > > On Fri, Feb 17, 2023 at 10:21:58AM +0800, Yu Kuai wrote:
> > > > > > From: Yu Kuai <yukuai3@huawei.com>
> > > > > > 
> > > > > > Changes from RFC:
> > > > > >    - remove the patch to factor out GD_NEED_PART_SCAN
> > > > > > 
> > > > > > Yu Kuai (2):
> > > > > >     block: Revert "block: Do not reread partition table on exclusively
> > > > > >       open device"
> > > > > >     block: fix scan partition for exclusively open device again
> > > > > 
> > > > > Hi Yu kuai,
> > > > > 
> > > > > Looks the original issue starts to re-appear now with the two patches:
> > > > > 
> > > > > https://lore.kernel.org/linux-block/20221130135344.2ul4cyfstfs3znxg@quack3/
> > > > > 
> > > > > 
> > > > > And underlying disk partition and raid partition can be observed at the
> > > > > same time.
> > > > > 
> > > > > Can you take a look?
> > > > Yes, thanks for the report. I realize that sda1 adn sdb1 is created
> > > > while raid open sda and sdb excl, and I think this problem should exist
> > > > before this patchset.
> > > 
> > > Looks not reproduced before applying your two patches, that is
> > > exactly what Jan
> > > tried to fix with 36369f46e917 ("block: Do not reread partition
> > > table on exclusively open device").
> > 
> > Hi, Ming
> > 
> > I just tried your test with this patchset reverted, and I can still
> > reporduce the problem myself.
> 
> Oops, I forgot to revert the first patch. It's right the problem can't
> be reporduced.
> > 
> > raid only open this device excl, and disk_scan_partitions is not called:
> > 
> > md_import_device
> >   blkdev_get_by_devo
> > 
> > I need to add some debuginfo to figure out how GD_NEED_PART_SCAN is set
> > for sda after raid is stopped. And this should explain why sda1 is
> > created.
> 
> I found how GD_NEED_PART_SCAN is set now, in patch 2, this is set before
> bd_prepare_to_claim, so preciously faild part scan will still set this
> bit, and following patch shold fix this problem:

Just run quick test, the issue won't be reproduced with your patch, and
the change looks rational too,

Reviewed-by: Ming Lei <ming.lei@redhat.com>


Thanks,
Ming