Date: Wed, 26 Aug 2015 15:00:57 +0200
From: David Sterba <dsterba@suse.cz>
To: Peng Tao <tao.peng@primarydata.com>
Cc: Linux NFS Mailing List <linux-nfs@vger.kernel.org>,
        Trond Myklebust <trond.myklebust@primarydata.com>,
        Anna Schumaker <anna.schumaker@netapp.com>,
        Christoph Hellwig <hch@infradead.org>, Zach Brown <zab@zabbo.net>,
        Darren Hart <dvhart@linux.intel.com>,
        Bruce Fields <bfields@fieldses.org>,
        Jeff Layton <jeff.layton@primarydata.com>, linux-btrfs@vger.kernel.org,
        Devel FS Linux <linux-fsdevel@vger.kernel.org>
Subject: Re: [PATCH RFC 02/11] vfs/btrfs: add .clone_range file operation
Message-ID: <20150826130057.GW10756@suse.cz>
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 <20150826080111.GV10756@twin.jikos.cz>
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On Wed, Aug 26, 2015 at 04:31:09PM +0800, Peng Tao wrote:
> >> -#define BTRFS_IOC_CLONE        _IOW(BTRFS_IOCTL_MAGIC, 9, int)
> >
> > The ioctl definition reuses the BTRFS_IOCTL_MAGIC (0x94), which is IMHO
> > wrong.
> >
> I thought it breaks ABI if we choose a different value for the type
> field of the ioctl. Am I misunderstanding it?

The ioctl is now private to btrfs, you're going to define the new ABI so
it IMHO should use the generic filesystem ioctl magic/namespace.