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

[Daniel Lezcano]

Christophe Varoqui wrote:
> On jeu., 2009-11-12 at 16:33 +0100, Daniel Lezcano wrote:
>   
>> 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.
>>
>>     
> I see, the centos image I got from the openvz community has /etc/mtab
> linked to /proc/mounts
>   

Hey, tricky case :)

> Removing the link restores the expected behaviour. Thank you for your
> help.
>   
You are welcome :)

Thanks
   -- Daniel