Return-Path: Received: from bombadil.infradead.org ([198.137.202.133]:54126 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752762AbeDRHHK (ORCPT ); Wed, 18 Apr 2018 03:07:10 -0400 Date: Wed, 18 Apr 2018 00:07:09 -0700 From: Christoph Hellwig To: "J. Bruce Fields" Cc: Christoph Hellwig , Olga Kornievskaia , linux-nfs@vger.kernel.org Subject: Re: [PATCH v8 0/9] NFSD support for async COPY Message-ID: <20180418070709.GB8764@infradead.org> References: <20180413170158.17589-1-kolga@netapp.com> <20180414072202.GA6514@infradead.org> <20180416214522.GC2634@parsley.fieldses.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20180416214522.GC2634@parsley.fieldses.org> Sender: linux-nfs-owner@vger.kernel.org List-ID: On Mon, Apr 16, 2018 at 05:45:22PM -0400, J. Bruce Fields wrote: > On Sat, Apr 14, 2018 at 12:22:02AM -0700, Christoph Hellwig wrote: > > What is the use case for adding all these crazy complications? > > Is there anything specific that you think is too complicated? > > I know you don't think server-to-server copy offload is worth the > trouble, but I haven't seen you actually explain why (beyond just that > it's more complicated). For one all code is buggy and introduces issues, and code implementing asynchronous, distributed state machines is even more so. So a large chunk of code is a big warning sign. Especially if it isn't actually useful to normal users.