From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from userp1040.oracle.com ([156.151.31.81]:18440 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753962AbaIOQnn (ORCPT ); Mon, 15 Sep 2014 12:43:43 -0400 Message-ID: <54171711.8010107@oracle.com> Date: Tue, 16 Sep 2014 00:42:57 +0800 From: Anand Jain MIME-Version: 1.0 To: Sam Thursfield , linux-btrfs@vger.kernel.org CC: baserock-dev@baserock.org, johannes.hirte@datenkhaos.de, xavier.gnata@gmail.com, 1i5t5.duncan@cox.net Subject: Re: Unable to mount multiple subvolumes of a single disk References: <5417022A.5000101@codethink.co.uk> In-Reply-To: <5417022A.5000101@codethink.co.uk> Content-Type: text/plain; charset=utf-8; format=flowed Sender: linux-btrfs-owner@vger.kernel.org List-ID: Logs from Sam, tells the problem clearly. mount is using /dev/sda, but mount error message and kernel is using /dev/vda. ---------------------- $ mount /dev/sda /home -t btrfs -o subvol=/state/home,defaults,rw,noatime mount: /dev/vda is already mounted or /home busy /dev/vda is already mounted on / $ btrfs fi show Label: 'baserock' uuid: 9a1b9724-d64c-4709-9ce0-b7ad98054385 Total devices 1 FS bytes used 1.45GB devid 1 size 4.00GB used 2.06GB path /dev/vda ---------------------- any idea what provided kernel the path /dev/vda ? Do we still have /dev/vda at the time of above mount cmd. ? Further if you use /dev/vda instead of /dev/sda for the mount, it should work. Provided vda is still there. Thanks, Anand On 15/09/2014 23:13, Sam Thursfield wrote: > Hi! > > I'm having an issue with the 3.17rc5 kernel which prevents having > multiple subvolumes of the same disk mounted. > > I'm not sure exactly the cause. I thought it might be because in my > system the root file system is itself a subvolume of the disk I'm trying > to mount. But if I create a second disk image with two subvolumes, the > same thing occurs -- I can only mount one of them at a time. > > I've attached the output of a few commands, please let me know if you > want more info (I'm not subscribed to the list, please keep me in To:). > > We've bisected and found that the exact commit that changed the > behaviour is this one: > https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=b96de000bc8bc9688b3a2abea4332bd57648a49f > > > I'm afraid I'm not familiar with the Btrfs code base and so I don't > understand the exact meaning of the comments in that commit. > > Thanks > Sam >