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Date:   Tue, 5 Jan 2021 08:50:09 +0100
From:   Christoph Hellwig <hch@lst.de>
To:     Minwoo Im <minwoo.im.dev@gmail.com>
Cc:     Christoph Hellwig <hch@lst.de>, linux-block@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
        Jens Axboe <axboe@kernel.dk>,
        Alexander Viro <viro@zeniv.linux.org.uk>,
        Chaitanya Kulkarni <Chaitanya.Kulkarni@wdc.com>
Subject: Re: [RFC PATCH V3 1/1] block: reject I/O for same fd if block size
 changed
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References: <20210104130659.22511-1-minwoo.im.dev@gmail.com> <20210104130659.22511-2-minwoo.im.dev@gmail.com> <20210104171108.GA27235@lst.de> <20210104171141.GB27235@lst.de> <20210105010456.GA6454@localhost.localdomain>
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On Tue, Jan 05, 2021 at 10:04:56AM +0900, Minwoo Im wrote:
> It was a point that I really would like to ask by RFC whether we can
> have backpointer to the gendisk from the request_queue.  And I'd like to
> have it to simplify this routine and for future usages also.

I think it is the right thing to do, at least mid-term, although I
don't want to enforce the burden on you right now.

> I will restrict this one by checking GENHD_FL_UP flag from the gendisk
> for the next patch.
> 
> > 
> > Alternatively we could make this request_queue QUEUE* flag for now.
> 
> As this patch rejects I/O from the block layer partition code, can we
> have this flag in gendisk rather than request_queue ?

For now we can as the request_queue is required.  I have some plans to
clean up this area, but just using a request_queue flag for now is
probably the simplest, even if it means more work for me later.