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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 93CABCA9EC2 for ; Tue, 29 Oct 2019 06:53:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7245420663 for ; Tue, 29 Oct 2019 06:53:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727134AbfJ2GxT (ORCPT ); Tue, 29 Oct 2019 02:53:19 -0400 Received: from rin.romanrm.net ([91.121.75.85]:60436 "EHLO rin.romanrm.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726566AbfJ2GxT (ORCPT ); Tue, 29 Oct 2019 02:53:19 -0400 Received: from natsu (natsu.2.romanrm.net [IPv6:fd39:aa:7359:7f90:e99e:8f1b:cfc9:ccb8]) by rin.romanrm.net (Postfix) with SMTP id 3622A2027D; Tue, 29 Oct 2019 06:53:17 +0000 (UTC) Date: Tue, 29 Oct 2019 11:53:17 +0500 From: Roman Mamedov To: Qu Wenruo Cc: linux-btrfs@vger.kernel.org Subject: Re: [RFC PATCH] btrfs: rescue: Introduce new rescue mount option, rescue=skipdatacsum, to skip data csum verification Message-ID: <20191029115317.03b43d94@natsu> In-Reply-To: <20191029062149.217995-1-wqu@suse.com> References: <20191029062149.217995-1-wqu@suse.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On Tue, 29 Oct 2019 14:21:49 +0800 Qu Wenruo wrote: > Here we introduce a new rescue= mount option to completely skip data > csum check. > Since data csum check is completely skipped, for profiles with extra > mirrors/copies, it will return the first copy only, which is not > optimized, but should be good enough for rescue usage. > > This option only affects data csum verification, doesn't affect data > csum calcuation, so new data write will still be protected by csum (if > it doesn't get affected by csum tree corruption). Maybe just make the "nodatasum" mount option skip verification of existing checksums as well? Actually before seeing this patch I believed "nodatasum" already does that. Also for consistency note that datasum/nodatasum call it just "sum" in the mount option name, not "csum". -- With respect, Roman