From: Azat Khuzhin Subject: Re: About changing the UUID of external journal device Date: Wed, 25 Jun 2014 17:28:33 +0400 Message-ID: <20140625132833.GG643@azat> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-ext4@vger.kernel.org To: Chin Tzung Cheng Return-path: Received: from mail-lb0-f170.google.com ([209.85.217.170]:60079 "EHLO mail-lb0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756992AbaFYN2k (ORCPT ); Wed, 25 Jun 2014 09:28:40 -0400 Received: by mail-lb0-f170.google.com with SMTP id 10so1872317lbg.29 for ; Wed, 25 Jun 2014 06:28:39 -0700 (PDT) Content-Disposition: inline In-Reply-To: Sender: linux-ext4-owner@vger.kernel.org List-ID: On Wed, Jun 25, 2014 at 05:31:15PM +0800, Chin Tzung Cheng wrote: > Hi, > I have problem while I create a ext4 volume with external journal device. > The UUID of external journal device is not the one I specify. > > First, I create a journal device(/dev/sda4). > > [root@localhost sbin]# ./mke2fs -O journal_dev /dev/sda4 > [root@localhost sbin]# ./blkid /dev/sda4 > /dev/sda4: UUID="1313c286-7803-4a40-9010-74964554d13f" TYPE="jbd" > > I use tune2fs to change the UUID of journal device. blkid shows the > UUID is changed. > > [root@localhost sbin]# ./tune2fs /dev/sda4 -U > aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa > [root@localhost sbin]# ./blkid /dev/sda4 > /dev/sda4: UUID="aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa" TYPE="jbd" > > Make an ext4 volume with external journal device (dev/sda4) > > [root@localhost sbin]# ./mke2fs /dev/sda3 -t ext4 -J device=/dev/sda4 > > [root@localhost sbin]# ./dumpe2fs -h /dev/sda3 | grep UUID > dumpe2fs 1.42.10 (18-May-2014) > Filesystem UUID: d8f038e5-9539-4b1d-8ccb-63cc56771fc5 > Journal UUID: 1313c286-7803-4a40-9010-74964554d13f > > However, the journal device UUID of ext4 volume is still the old one. > It's not the new one. > > Test environment > Kernel version: 3.12.10 > e2fsprogs version: 1.42.10 > > Any help would be appreciated. Hi, I'm *not an expert*, but here is what you can do: [ vdc === sda3, vdb ===sda4 ] # e2fsck -vvv /dev/vdc e2fsck 1.42.10 (18-May-2014) External journal does not support this filesystem /dev/vdc: ********** WARNING: Filesystem still has errors ********** # debugfs -w /dev/vdc debugfs 1.42.10 (18-May-2014) debugfs: set_super_value journal_uuid "aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa" # dumpe2fs -h /dev/vdc | fgrep UUID dumpe2fs 1.42.10 (18-May-2014) Filesystem UUID: 85050e89-6b52-4146-b697-8439a7b04b13 Journal UUID: aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa # e2fsck -vvv /dev/vdc e2fsck 1.42.10 (18-May-2014) External journal has multiple filesystem users (unsupported). /dev/vdc: ********** WARNING: Filesystem still has errors ********** # dumpe2fs -h /dev/vdb | fgrep Journal\ users: -A10 dumpe2fs 1.42.10 (18-May-2014) Journal users: 4a383cca-3d1e-40c3-8ab2-38bc5f770eea fa89e7ed-ff86-4c94-bc91-739ad888c4a4 85050e89-6b52-4146-b697-8439a7b04b13 [ Only in case when you have multiple users for journal dev: ] ------------------------------------------------------------- # mke2fs -O journal_dev /dev/vdb mke2fs 1.42.10 (18-May-2014) /dev/vdb contains a jbd file system Proceed anyway? (y,n) y Creating filesystem with 1310720 4k blocks and 0 inodes Filesystem UUID: e81064f2-fd57-4af3-b690-06985cbbe4b0 Superblock backups stored on blocks: Zeroing journal device: # tune2fs /dev/vdb -U aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa # e2fsck -f /dev/vdc e2fsck 1.42.10 (18-May-2014) Pass 1: Checking inodes, blocks, and sizes Pass 2: Checking directory structure Pass 3: Checking directory connectivity Pass 4: Checking reference counts Pass 5: Checking group summary information /dev/vdc: 11/327680 files (0.0% non-contiguous), 23134/1310720 blocks I will try to dig into sources, to find the reason. > > Thanks, > chintzung > -- > To unsubscribe from this list: send the line "unsubscribe linux-ext4" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- Respectfully Azat Khuzhin