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Date:   Thu, 3 Dec 2020 09:53:39 +0100
From:   Christoph Hellwig <hch@lst.de>
To:     "Martin K. Petersen" <martin.petersen@oracle.com>
Cc:     Christoph Hellwig <hch@lst.de>, Jens Axboe <axboe@kernel.dk>,
        Oleksii Kurochko <olkuroch@cisco.com>,
        Sagi Grimberg <sagi@grimberg.me>,
        Mike Snitzer <snitzer@redhat.com>,
        Ilya Dryomov <idryomov@gmail.com>,
        Dongsheng Yang <dongsheng.yang@easystack.cn>,
        ceph-devel@vger.kernel.org, dm-devel@redhat.com,
        linux-block@vger.kernel.org, linux-nvme@lists.infradead.org
Subject: Re: [PATCH 1/4] block: add a hard-readonly flag to struct gendisk
Message-ID: <20201203085339.GA17110@lst.de>
References: <20201129181926.897775-1-hch@lst.de> <20201129181926.897775-2-hch@lst.de> <yq17dpza6nz.fsf@ca-mkp.ca.oracle.com>
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On Wed, Dec 02, 2020 at 11:04:33PM -0500, Martin K. Petersen wrote:
> 
> Hi Christoph!
> 
> >  - If BLKROSET is used to set a whole-disk device read-only, any
> >    partitions will end up in a read-only state until the user
> >    explicitly clears the flag.
> 
> This no longer appears to be the case with your tweak.

True.

> 
> It's very common for database folks to twiddle the read-only state of
> block devices and partitions. I know that our users will find it very
> counter-intuitive that setting /dev/sda read-only won't prevent writes
> to /dev/sda1.

What I'm worried about it is that this would be a huge change from the
historic behavior.