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=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 4786DC49ED9 for ; Thu, 12 Sep 2019 10:28:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1BCC720692 for ; Thu, 12 Sep 2019 10:28:51 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="Nh4SI5rn" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730909AbfILK2u (ORCPT ); Thu, 12 Sep 2019 06:28:50 -0400 Received: from userp2120.oracle.com ([156.151.31.85]:57336 "EHLO userp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730450AbfILK2t (ORCPT ); Thu, 12 Sep 2019 06:28:49 -0400 Received: from pps.filterd (userp2120.oracle.com [127.0.0.1]) by userp2120.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x8CASilP174041; Thu, 12 Sep 2019 10:28:46 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=subject : to : references : from : message-id : date : mime-version : in-reply-to : content-type : content-transfer-encoding; s=corp-2019-08-05; bh=YQZtYBDgbt0ISgq54B3JkvS4j2NRxVXhkib0yAMrNak=; b=Nh4SI5rn/ftVYZMUCWEqrF9jMKczo1fpegkG+U0Iayjrg4gI5T088d/MRx/i7CC6JHSJ 59rUcfKDQnwSUMX+eH74LyjyL39xR21/4bP/bk91XRgIqMOnmfw5T1mZpvsCIhWJim4P xLKs6T/rcNTDY9cNCeV1bEUCQ8LYWJp6TKTsNB/woWljMd8nbHaRjX2lx615aqM5det6 sQ7TGVz/GnPxFifOYhdYo4QIzkyTZBUC16Zxqjm8BLt2GEvYTSTHe+HpPRTTH53Dr99N UwccIy0FhJFzM7ShjNz1Pcxo/wYN/qUT6ow9Zpl3YW6y8ICacxaQqWS32sTs0omYytx/ JQ== Received: from userp3030.oracle.com (userp3030.oracle.com [156.151.31.80]) by userp2120.oracle.com with ESMTP id 2uw1jkqh0q-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 12 Sep 2019 10:28:46 +0000 Received: from pps.filterd (userp3030.oracle.com [127.0.0.1]) by userp3030.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x8CASd9Z098934; Thu, 12 Sep 2019 10:28:46 GMT Received: from userv0121.oracle.com (userv0121.oracle.com [156.151.31.72]) by userp3030.oracle.com with ESMTP id 2uy8w9s6tt-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 12 Sep 2019 10:28:41 +0000 Received: from abhmp0003.oracle.com (abhmp0003.oracle.com [141.146.116.9]) by userv0121.oracle.com (8.14.4/8.13.8) with ESMTP id x8CARTXl005594; Thu, 12 Sep 2019 10:27:29 GMT Received: from [10.190.130.61] (/192.188.170.109) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Thu, 12 Sep 2019 03:27:29 -0700 Subject: Re: [PATCH] btrfs: volumes: Allow missing devices to be writeable To: Qu Wenruo , linux-btrfs@vger.kernel.org References: <20190829071731.11521-1-wqu@suse.com> From: Anand Jain Message-ID: <7e9294de-1859-886a-3ac3-9659e70463d7@oracle.com> Date: Thu, 12 Sep 2019 18:27:25 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.14; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20190829071731.11521-1-wqu@suse.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9377 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1906280000 definitions=main-1909120111 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9377 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1906280000 definitions=main-1909120111 Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org There is previous work [1] [1] https://lore.kernel.org/linux-btrfs/1461812780-538-1-git-send-email-anand.jain@oracle.com/ I guess it was on purpose that missing device is not part of alloc chunk, so to have lesser impact due to writehole bug. My target is to fix the writehole first, and then this and other bugs. > [FIX] > Just consider the missing devices as WRITABLE, so we allocate new chunks > on them to maintain old profiles. IMO. In a 3-disks raid1 when one of the disk fails, we still need the _new writes_ not to be degraded. Just use two available disks. This fix fails that idea which is being followed now. Thanks, Anand