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Date:   Tue, 7 Jul 2020 19:53:12 +0200
From:   Christoph Hellwig <hch@lst.de>
To:     Ming Lei <ming.lei@redhat.com>
Cc:     Jens Axboe <axboe@kernel.dk>, Christoph Hellwig <hch@lst.de>,
        linux-block@vger.kernel.org
Subject: Re: [PATCH 2/2] block: loop: delete partitions after clearing &
 changing fd
Message-ID: <20200707175312.GB3730@lst.de>
References: <20200707084552.3294693-1-ming.lei@redhat.com> <20200707084552.3294693-3-ming.lei@redhat.com>
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On Tue, Jul 07, 2020 at 04:45:52PM +0800, Ming Lei wrote:
> After clearing fd or changing fd, we have to delete old partitions,
> otherwise they may become ghost partitions.
> 
> Fix this issue by clearing GENHD_FL_NO_PART_SCAN during calling
> bdev_disk_changed() which won't drop old partitions if GENHD_FL_NO_PART_SCAN
> isn't set.

I don't think messing with GENHD_FL_NO_PART_SCAN is a good idea, as
that will also cause an actual partition scan.  But except for historic
reasons I can't think of a good idea to even check for
GENHD_FL_NO_PART_SCAN in blk_drop_partitions.