From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from magic.merlins.org ([209.81.13.136]:57023 "EHLO mail1.merlins.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752335AbaCWSJP (ORCPT ); Sun, 23 Mar 2014 14:09:15 -0400 Received: from svh-gw.merlins.org ([173.11.111.145]:39663 helo=legolas.merlins.org) by mail1.merlins.org with esmtpsa (Cipher TLS1.2:DHE_RSA_AES_128_CBC_SHA1:128) (Exim 4.80 #2) id 1WRmpY-0006VI-Dn by authid with srv_auth_plain for ; Sun, 23 Mar 2014 11:09:14 -0700 Received: from merlin by legolas.merlins.org with local (Exim 4.80) (envelope-from ) id 1WRmpX-0006Vs-Lc for linux-btrfs@vger.kernel.org; Sun, 23 Mar 2014 11:09:07 -0700 Date: Sun, 23 Mar 2014 11:09:07 -0700 From: Marc MERLIN To: linux-btrfs@vger.kernel.org Message-ID: <20140323180907.GA22171@merlins.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Subject: Cannot add device "is mounted" for unmounted drive that used to be in raidset that is mounted Sender: linux-btrfs-owner@vger.kernel.org List-ID: I found out that a drive that used to be part of a raid system that is mounted and running without it, btrfs apparently decides that the drive is part of the mounted raidset and in use. As a result, I had to eventually dd 0's over it, btrfs device scan, and finally I was able to use it again. btrfs should probably improve its check to see that the drive is not really used and let me format it. Longer details: On a running system, I re-added a drive, it showed up as /dev/sdm1 I decrypted it cryptsetup luksOpen /dev/sdm1 crypt_sdm1 But I can't add it: polgara:/mnt/btrfs_backupcopy# btrfs device add -f /dev/mapper/crypt_sdm1 . /dev/mapper/crypt_sdm1 is mounted however, I can format it as ext4, mount it, write to it, unmount it, and I still get the same error: polgara:/mnt/btrfs_backupcopy# mke2fs -t ext4 /dev/mapper/crypt_sdm1 polgara:/mnt/btrfs_backupcopy# mount /dev/mapper/crypt_sdm1 /mnt/mnt polgara:/mnt/btrfs_backupcopy# Mar 23 10:48:31 polgara kernel: [38645.955263] EXT4-fs (dm-10): mounted filesystem with ordered data mode. Opts: (null) polgara:/mnt/btrfs_backupcopy# umount /mnt/mnt polgara:/mnt/btrfs_backupcopy# btrfs device add -f /dev/mapper/crypt_sdm1 . /dev/mapper/crypt_sdm1 is mounted polgara:/mnt/btrfs_backupcopy# fuser -v /dev/mapper/crypt_sdm1 polgara:/mnt/btrfs_backupcopy# lsof -n | grep -E '(dm-10|sdm)' polgara:/mnt/btrfs_backupcopy# mkfs.btrfs -f /dev/mapper/crypt_sdm1 Error: /dev/mapper/crypt_sdm1 is mounted polgara:/mnt/btrfs_backupcopy# In the end, I had to run dd if=/dev/zero of=/dev/mapper/crypt_sdm1 bs=1M for btrfs to stop telling me the filesystem was mounted. Marc -- "A mouse is a device used to point at the xterm you want to type in" - A.S.R. Microsoft is to operating systems .... .... what McDonalds is to gourmet cooking Home page: http://marc.merlins.org/ | PGP 1024R/763BE901