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Date:   Thu, 18 May 2023 15:56:03 +0200
From:   Christian Brauner <brauner@kernel.org>
To:     Christoph Hellwig <hch@lst.de>
Cc:     Jens Axboe <axboe@kernel.dk>, Al Viro <viro@zeniv.linux.org.uk>,
        "Darrick J. Wong" <djwong@kernel.org>, linux-block@vger.kernel.org,
        linux-fsdevel@vger.kernel.org, linux-xfs@vger.kernel.org
Subject: Re: [PATCH 5/9] block: introduce holder ops
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On Thu, May 18, 2023 at 03:12:16PM +0200, Christoph Hellwig wrote:
> On Thu, May 18, 2023 at 10:13:04AM +0200, Christian Brauner wrote:
> > Fwiw, I didn't mean to have a special device handler for an O_PATH fd.
> > I really just tried to figure out whether it would make sense to have an
> > fd-based block device lookup function because right now we only have
> > blkdev_get_by_path() and we'd be passing blkdev fds through the mount
> > api. But I understand now how I'd likely do it. So now just finding time
> > to actually implement it.
> 
> What's wrong with blkdev_get_by_dev(file_inode(file)->i_rdev) after
> the sanity checks from lookup_bdev (S_ISBLK and may_open_dev)?

Yeah, that's what I realized could work fine. I just need to check all
fses how they currently do this and how to do this cleanly.