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Date: Thu, 2 May 2024 19:23:54 +0100
From: Al Viro <viro@zeniv.linux.org.uk>
To: John Groves <John@groves.net>
Cc: Jonathan Corbet <corbet@lwn.net>,
	Jonathan Cameron <Jonathan.Cameron@huawei.com>,
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Subject: Re: [RFC PATCH v2 08/12] famfs: module operations & fs_context
Message-ID: <20240502182354.GH2118490@ZenIV>
References: <cover.1714409084.git.john@groves.net>
 <86694a1a663ab0b6e8e35c7b187f5ad179103482.1714409084.git.john@groves.net>
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Sender: Al Viro <viro@ftp.linux.org.uk>

On Mon, Apr 29, 2024 at 12:04:24PM -0500, John Groves wrote:
> +	case S_IFREG:
> +		inode->i_op = NULL /* famfs_file_inode_operations */;
> +		inode->i_fop = NULL /* &famfs_file_operations */;

Don't.  We should never, ever store NULL in either.  
	inode->i_op = &empty_iops;
	inode->i_fop = &no_open_fops;
in inode_init_always() is there precisely to avoid doing that.

IOW, the right thing would be something along the lines of
		/* inode->i_op = famfs_file_inode_operations */;
if you want a placeholder for a patch later in the series - or
simply /* methods will be set here in a commit or two */