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Date:   Wed, 16 Nov 2022 16:49:57 -0500
From:   Mike Snitzer <snitzer@redhat.com>
To:     Yu Kuai <yukuai1@huaweicloud.com>
Cc:     hch@lst.de, axboe@kernel.dk, agk@redhat.com, snitzer@kernel.org,
        dm-devel@redhat.com, linux-block@vger.kernel.org,
        linux-kernel@vger.kernel.org, yukuai3@huawei.com,
        yi.zhang@huawei.com
Subject: Re: [PATCH v3 06/10] dm: track per-add_disk holder relations in DM
Message-ID: <Y3VbBeuQvOLKH81a@redhat.com>
References: <20221115141054.1051801-1-yukuai1@huaweicloud.com>
 <20221115141054.1051801-7-yukuai1@huaweicloud.com>
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On Tue, Nov 15 2022 at  9:10P -0500,
Yu Kuai <yukuai1@huaweicloud.com> wrote:

> From: Christoph Hellwig <hch@lst.de>
> 
> dm is a bit special in that it opens the underlying devices.  Commit
> 89f871af1b26 ("dm: delay registering the gendisk") tried to accommodate
> that by allowing to add the holder to the list before add_gendisk and
> then just add them to sysfs once add_disk is called.  But that leads to
> really odd lifetime problems and error handling problems as we can't
> know the state of the kobjects and don't unwind properly.  To fix this
> switch to just registering all existing table_devices with the holder
> code right after add_disk, and remove them before calling del_gendisk.
> 
> Fixes: 89f871af1b26 ("dm: delay registering the gendisk")
> Reported-by: Yu Kuai <yukuai3@huawei.com>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> Signed-off-by: Yu Kuai <yukuai3@huawei.com>

Reviewed-by: Mike Snitzer <snitzer@kernel.org>