From mboxrd@z Thu Jan  1 00:00:00 1970
From: Eric Wong <normalperson@yhbt.net>
Subject: Re: [RFC v0 1/4] vfs: add copy_range syscall and vfs entry point
Date: Wed, 15 May 2013 19:44:05 +0000
Message-ID: <20130515194405.GA28720@dcvr.yhbt.net>
References: <1368566126-17610-1-git-send-email-zab@redhat.com>
 <1368566126-17610-2-git-send-email-zab@redhat.com>
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Cc: "Martin K. Petersen" <martin.petersen@oracle.com>,
	Trond Myklebust <Trond.Myklebust@netapp.com>,
	linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-btrfs@vger.kernel.org, linux-nfs@vger.kernel.org
To: Zach Brown <zab@redhat.com>
Return-path: <linux-kernel-owner@vger.kernel.org>
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In-Reply-To: <1368566126-17610-2-git-send-email-zab@redhat.com>
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Zach Brown <zab@redhat.com> wrote:
> This adds a syscall and vfs entry point for clone_range which offloads
> data copying between existing files.
> 
> The syscall is a thin wrapper around the vfs entry point.  Its arguments
> are inspired by sys_splice().

Why introduce a new syscall instead of extending sys_splice?

Perhaps adding a new SPLICE_F_COPYRANGE flag to avoid compatibility
problems with userspace which may expect ESPIPE when given two non-pipes
would be useful.

If the user doesn't need a out offset, then sendfile() should also be
able to transparently utilize COPY/CLONE_RANGE, too.