From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cn.fujitsu.com ([59.151.112.132]:47295 "EHLO heian.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1753435AbaF3CTF convert rfc822-to-8bit (ORCPT ); Sun, 29 Jun 2014 22:19:05 -0400 Message-ID: <53B0C93E.8050500@cn.fujitsu.com> Date: Mon, 30 Jun 2014 10:19:42 +0800 From: Qu Wenruo MIME-Version: 1.0 To: =?UTF-8?B?U8OpYmFzdGllbiBST0hBVVQ=?= , Chris Murphy CC: Subject: Re: Can't mount subvolume with ro option References: <53ADCF0B.4010109@free.fr> <54D8214E-1C00-43AB-A68A-D450069D878C@colorremedies.com> <53AEA0D3.8080905@free.fr> In-Reply-To: <53AEA0D3.8080905@free.fr> Content-Type: text/plain; charset="UTF-8"; format=flowed Sender: linux-btrfs-owner@vger.kernel.org List-ID: -------- Original Message -------- Subject: Re: Can't mount subvolume with ro option From: Sébastien ROHAUT To: Chris Murphy Date: 2014年06月28日 19:02 > Le 28/06/2014 00:12, Chris Murphy a écrit : >> On Jun 27, 2014, at 4:08 PM, Chris Murphy >> wrote: >> >>> On Jun 27, 2014, at 2:07 PM, Sébastien ROHAUT >>> wrote: >>> >>>> Hi, >>>> >>>> In the wiki, it's said we can mount subvolumes with different mount >>>> options. nosuid, nodev, rw and ro are listed, as valid generic >>>> mount options. >>> This might require 3.15. I don't recall it working with early 3.14 >>> kernels, but by 3.14.3 I'd moved onto testing 3.15. >> >> [root@f20v ~]# mount /dev/sda3 /mnt >> [root@f20v ~]# btrfs subvol create /mnt/test >> Create subvolume '/mnt/test' >> [root@f20v ~]# umount /mnt >> [root@f20v ~]# mount -o ro,subvol=test /dev/sda3 /mnt >> mount: /dev/sda3 is already mounted or /mnt busy >> /dev/sda3 is already mounted on / >> /dev/sda3 is already mounted on /home >> /dev/sda3 is already mounted on /var >> /dev/sda3 is already mounted on /boot >> [root@f20v ~]# uname -r >> 3.14.6-200.fc20.x86_64 >> >> >> I don't know if this feature will be backported to stable kernels. If >> not, then probably the wiki should say it's a 3.15+ feature. >> Chris Murphy >> >> > Thank you for your answer. I'm actually moving to a Fedora Rawhide > (3.16 kernel). > > Sebastien Rohaut > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html When testing on 3.15.2-ARCH alone with 3.16-rc2, the problem can also be reproduced. But I can't always reproduce it, sometimes I was able to mount subvol with ro, somtimes not. So I think the problem needs to be investigated further. Thanks, Qu