[lxc-devel] /proc/mounts and bind mounts

[Daniel Lezcano]

Christophe Varoqui wrote:
> On jeu., 2009-11-12 at 10:22 +0100, Daniel Lezcano wrote:
>   
>> Christophe Varoqui wrote:
>>     
>>> Hi Daniel, all,
>>>
>>> After bind mounting /tmp on /unxtstencap in a container, the
>>> corresponding entry in /proc/mounts is displayed as :
>>> /dev/mapper/zezette-root /unxdrpencap ext4
>>> rw,relatime,errors=remount-ro,barrier=1,data=ordered 0 0
>>>
>>> /dev/mapper/zezette-root being the device holding /tmp.
>>>
>>> The source directory information is lost. Is that expected ?
>>>   
>>>       
>> Yes and that's already the case without containers. The mount 
>> information, done with the mount(1) command, write information in 
>> /etc/mtab. You should check this file instead.
>>     
>
> In the hosting system:
>
> cvaroqui at zezette:/opt/lxc/rootfs.vm5/service$ sudo mount -t none -o
> bind /tmp /mnt
> cvaroqui at zezette:/opt/lxc/rootfs.vm5/service$ tail -1 /etc/mtab 
> /tmp /mnt none rw,bind 0 0
>
> It seems the information is not discarded. May be that's because the
> host is ubuntu and the guest is Centos 5 then ?
>   
What I meant is the mtab shows the information you are looking for, 
while the kernel shows a different information in /proc/mounts.
The mount command shows the content of mtab. So if you want to get the 
source directory information, you should use the mount command or look 
at the /etc/mtab.