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Date:   Mon, 24 Jul 2023 18:40:17 +0200
From:   Christoph Hellwig <hch@lst.de>
To:     Nitesh Shetty <nj.shetty@samsung.com>
Cc:     Alexander Viro <viro@zeniv.linux.org.uk>,
        Christian Brauner <brauner@kernel.org>, hch@lst.de,
        gost.dev@samsung.com, Anuj Gupta <anuj20.g@samsung.com>,
        linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] fs/read_write: Enable copy_file_range for block device.
Message-ID: <20230724164017.GC26430@lst.de>
References: <CGME20230724060655epcas5p24f21ce77480885c746b9b86d27585492@epcas5p2.samsung.com> <20230724060336.8939-1-nj.shetty@samsung.com>
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>  {
> -	struct inode *inode_in = file_inode(file_in);
> -	struct inode *inode_out = file_inode(file_out);
> +	struct inode *inode_in = file_in->f_mapping->host;
> +	struct inode *inode_out = file_out->f_mapping->host;

This doesn't directly have anything to do with block devices, as regular
files can also have a f_mapping that's different.  None of the file
systems actually supporting copy offload right now do, but changing
the dereference here is a correctness thing totally independent of
block device support.