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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 804D4C43140 for ; Thu, 5 Sep 2019 16:38:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4ED3A2082E for ; Thu, 5 Sep 2019 16:38:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389699AbfIEQiB (ORCPT ); Thu, 5 Sep 2019 12:38:01 -0400 Received: from verein.lst.de ([213.95.11.211]:50209 "EHLO verein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389096AbfIEQiA (ORCPT ); Thu, 5 Sep 2019 12:38:00 -0400 Received: by verein.lst.de (Postfix, from userid 2407) id 7A01468B05; Thu, 5 Sep 2019 18:37:56 +0200 (CEST) Date: Thu, 5 Sep 2019 18:37:56 +0200 From: Christoph Hellwig To: Goldwyn Rodrigues Cc: linux-fsdevel@vger.kernel.org, linux-btrfs@vger.kernel.org, darrick.wong@oracle.com, hch@lst.de, linux-xfs@vger.kernel.org, Goldwyn Rodrigues Subject: Re: [PATCH 02/15] iomap: Read page from srcmap if IOMAP_F_COW is set Message-ID: <20190905163756.GA22883@lst.de> References: <20190905150650.21089-1-rgoldwyn@suse.de> <20190905150650.21089-3-rgoldwyn@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190905150650.21089-3-rgoldwyn@suse.de> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Thu, Sep 05, 2019 at 10:06:37AM -0500, Goldwyn Rodrigues wrote: > - else if (iomap->flags & IOMAP_F_BUFFER_HEAD) > + } else if (iomap->flags & IOMAP_F_COW) { > + if (WARN_ON_ONCE(iomap->flags & IOMAP_F_BUFFER_HEAD)) { > + status = -EIO; > + goto out_no_page; > + } > + if (WARN_ON_ONCE(srcmap->type == IOMAP_HOLE && > + srcmap->addr != IOMAP_NULL_ADDR)) { Well, we want HOLES to have IOMAP_NULL_ADDR everywhere, so not sure why the assert is just here. > + status = -EIO; > + goto out_no_page; > + } > + status = __iomap_write_begin(inode, pos, len, page, srcmap); > + } else if (iomap->flags & IOMAP_F_BUFFER_HEAD) { > status = __block_write_begin_int(page, pos, len, NULL, iomap); > - else > + } else { > status = __iomap_write_begin(inode, pos, len, page, iomap); > + } Maybe a good way to structure this is: if (iomap->flags & IOMAP_F_BUFFER_HEAD) { if (WARN_ON_ONCE(iomap->flags & IOMAP_F_COW)) { status = -EIO; goto out_no_page; } status = __block_write_begin_int(page, pos, len, NULL, iomap); } else { status = __iomap_write_begin(inode, pos, len, page, (iomap->flags & IOMAP_F_COW) ? srcmap : iomap); }