From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from fw10a-lesia.wadns.net ([196.220.39.109]:47641 "EHLO fw10a.wadns.net" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753112AbaEUS0q (ORCPT ); Wed, 21 May 2014 14:26:46 -0400 Message-ID: <537CEFD6.9010407@swiftspirit.co.za> Date: Wed, 21 May 2014 20:26:30 +0200 From: Brendan Hide MIME-Version: 1.0 To: Qu Wenruo , Anand Jain CC: linux-btrfs@vger.kernel.org Subject: Re: [RFC PATCH 1/2] btrfs: Add missing device check in dev_info/rm_dev ioctl References: <1399357993-9254-1-git-send-email-quwenruo@cn.fujitsu.com> <1399357993-9254-2-git-send-email-quwenruo@cn.fujitsu.com> <5369E818.7000606@oracle.com> <537C19B9.8080203@cn.fujitsu.com> <537C235F.5030303@oracle.com> <537C285F.7080101@cn.fujitsu.com> In-Reply-To: <537C285F.7080101@cn.fujitsu.com> Content-Type: text/plain; charset=UTF-8; format=flowed Sender: linux-btrfs-owner@vger.kernel.org List-ID: On 2014/05/21 06:15 AM, Qu Wenruo wrote: > [snip] >> Further on top of your check_missing patch I am writing >> code to to handle disk reappear. I should be sending them >> all soon. > Disk reappear problem is also reproduce here. > > I am intersting about how will your patch to deal with. > Is your patch going to check super genertion to determing previously > missing device and > wipe reappeared superblock?(Wang mentioned it in the mail in Jan.) With md we have the bitmap feature that helps prevent resynchronising the entire disk when doing a "re-add". Wiping the superblock is *better* than what we currently have (corruption) - but hopefully the end goal is to be able to have it re-add *without* introducing corruption. > > IMO the reappear disk problem can also be resolved by not swap > tgtdev->uuid and srcdev->uuid, > which means tgtdev will not use the same uuid of srcdev. > > Thanks, > Qu >> >> Thanks, Anand >> -- __________ Brendan Hide http://swiftspirit.co.za/ http://www.webafrica.co.za/?AFF1E97