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Date: Mon, 29 Apr 2024 07:07:29 +0200
From: Christoph Hellwig <hch@lst.de>
To: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Christian Brauner <brauner@kernel.org>,
	Christoph Hellwig <hch@lst.de>, linux-block@vger.kernel.org,
	Jens Axboe <axboe@kernel.dk>, linux-btrfs@vger.kernel.org,
	"Rafael J. Wysocki" <rafael@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH 2/7] pktcdvd: sort set_blocksize() calls out
Message-ID: <20240429050729.GB32416@lst.de>
References: <20240427210920.GR2118490@ZenIV> <20240427211032.GB1495312@ZenIV>
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User-Agent: Mutt/1.5.17 (2007-11-01)

On Sat, Apr 27, 2024 at 10:10:32PM +0100, Al Viro wrote:
> 1) it doesn't make any sense to have ->open() call set_blocksize() on the
> device being opened - the caller will override that anyway.
> 
> 2) setting block size on underlying device, OTOH, ought to be done when
> we are opening it exclusive - i.e. as part of pkt_open_dev().  Having
> it done at setup time doesn't guarantee us anything about the state
> at the time we start talking to it.  Worse, if you happen to have
> the underlying device containing e.g. ext2 with 4Kb blocks that
> is currently mounted r/o, that set_blocksize() will confuse the hell
> out of filesystem.

I brought some of this before and didn't dare to touch it because I
have no way of testing this code.  The changes looks good to me:

Reviewed-by: Christoph Hellwig <hch@lst.de>

But I really wish we could find a dedicated tester for pktcdvd or
just drop this code..