From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.3 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D892CC43218 for ; Fri, 26 Apr 2019 14:47:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A7EDF2077B for ; Fri, 26 Apr 2019 14:47:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="sbavI2MS" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726228AbfDZOrH (ORCPT ); Fri, 26 Apr 2019 10:47:07 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:39570 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726039AbfDZOrH (ORCPT ); Fri, 26 Apr 2019 10:47:07 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=VFpwf0uER1KnB426+X7UPhdTtG2qivWWYDz6u/XxK1g=; b=sbavI2MSRVslbfYNWMJ8CH2gV qZXWW6P6OIWyK/t8anm9RmHQ+1qaj2s+x9TIXR5Tg/WFBSXfLhZvjWyAoCEGYJ2XORzognBfR5Wqs UYxNndXra6db+ftv2kBVYNZBfmnSlRK04528quRuNTrr3X9HZWontxJVP5ufGGrzy0I8cy1+cAbpi zs81GKmnYPKzI6FAn7x7k3F6tWxErEYig2Vc2PUrshvWyns8EouqYdNPcFv588BZAvfYwgUlEZji3 USy3Em0jkxc3Msas3qswjEBn12UycKskY1tFmidxo3Hu+bNexQsNe/JOpCSj8fdrjH3l+Kv2V+EKF xGvbNY8uQ==; Received: from hch by bombadil.infradead.org with local (Exim 4.90_1 #2 (Red Hat Linux)) id 1hK27y-00011k-L8; Fri, 26 Apr 2019 14:47:02 +0000 Date: Fri, 26 Apr 2019 07:47:02 -0700 From: Christoph Hellwig To: "Darrick J. Wong" Cc: Christoph Hellwig , Dave Chinner , Jerome Glisse , lsf-pc@lists.linux-foundation.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [LSF/MM TOPIC] Direct block mapping through fs for device Message-ID: <20190426144702.GA31264@infradead.org> References: <20190426013814.GB3350@redhat.com> <20190426062816.GG1454@dread.disaster.area> <20190426124553.GB12339@infradead.org> <20190426144507.GB178347@magnolia> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190426144507.GB178347@magnolia> User-Agent: Mutt/1.9.2 (2017-12-15) X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Fri, Apr 26, 2019 at 07:45:07AM -0700, Darrick J. Wong wrote: > Hmmm, this lease interface still doesn't support COW, right? > > (Right, xfs_pnfs.c bails out with -ENXIO for reflink files) Yes, but that is because no one bothered to do the work. pNFS/block and pNFS/scsi explicitly support a compatbile COW scheme, it is just that no implemented it yet (at all I think, not just for Linux..).