Re: [gentoo-user] Bind stole my /

[Mike Gilbert]

On Mon, Nov 9, 2015 at 2:36 PM, Jarry <mr.jarry@×××××.com> wrote:
> On 08-Nov-15 17:58, Mike Gilbert wrote:
>>
>> On Fri, Nov 6, 2015 at 12:19 PM, Jarry <mr.jarry@×××××.com> wrote:
>>>
>>> Hi Gentoo-users,
>>>
>>> I noted one strange thing today: It seems one of my servers lost "/"!
>>>
>>> vs5-dns ~ # df
>>> Filesystem    1K-blocks    Used Available Use% Mounted on
>>> /var/log/named 10138552 2223148   7377344  24% /chroot/dns/var/log/named
>>> tmpfs            308196     420    307776   1% /run
>>> dev               10240       0     10240   0% /dev
>>> shm             1540968       0   1540968   0% /dev/shm
>>> cgroup_root       10240       0     10240   0% /sys/fs/cgroup
>>> none            1048576       0   1048576   0% /var/tmp/portage
>>
>>
>> Is your /etc/mtab a regular file, or is it a symlink to
>> /proc/self/mounts? The latter is recommended.
>
>
> It is regular file. I never changed it...
>
> vs5-dns ~ # ls -l /etc/mtab
> -rw-r--r-- 1 root root 908 Nov  9 19:14 /etc/mtab
>
>> Anyway, please have a look at the contents of /etc/mtab,
>> /proc/self/mounts, and proc/self/mountinfo while named is running and
>> when it is stopped. If you pastebin them we can take a look for key
>> differences.
>
>
> With bind running:
> http://pastebin.com/wkTW6xAY
>
> without bind:
> http://pastebin.com/JG5FPNDW
>
> While I can see some differences there, I still do not understand
> why is "/" missing in "df" output. BTW I can not proove it, but this
> was not the case all the time. At least when I was tuning monitoring
> software, I'm pretty sure "/" was there...

It may be a bug.

Can you try replacing /etc/mtab with a symlink to /proc/self/mounts to
see if it makes any difference? That triggers different code paths in
several programs.