no need to use a temporary directory for pivoting

no need to use a temporary directory for pivoting

Ferenc Wagner <wferi@niif.hu> writes:

> Daniel Lezcano <dlezcano@fr.ibm.com> writes:
>
>> Ferenc Wagner wrote:
>>
>>> Daniel Lezcano <daniel.lezcano@free.fr> writes:
>>>
>>>> Ferenc Wagner wrote:
>>>>
>>>>> While playing with lxc-start, I noticed that /tmp is infested by
>>>>> empty lxc-r* directories: [...] Ok, this name comes from lxc-rootfs
>>>>> in conf.c:setup_rootfs.  After setup_rootfs_pivot_root returns, the
>>>>> original /tmp is not available anymore, so rmdir(tmpname) at the
>>>>> bottom of setup_rootfs can't achieve much.  Why is this temporary
>>>>> name needed anyway?  Is pivoting impossible without it?
>>>>
>>>> That was put in place with chroot, before pivot_root, so the distro's
>>>> scripts can remount their '/' without failing.
>>>>
>>>> Now we have pivot_root, I suppose we can change that to something cleaner...
>>>
>>> Like simply nuking it?  Shall I send a patch?
>>
>> Sure, if we can kill it, I will be glad to take your patch :)
>
> I can't see any reason why lxc-start couldn't do without that temporary
> recursive bind mount of the original root.  If neither do you, I'll
> patch it out and see if it still flies.

For my purposes the patch below works fine.  I only run applications,
though, not full systems, so wider testing is definitely needed.

Thanks,
Feri.

>From 98b24c13f809f18ab8969fb4d84defe6f812b25c Mon Sep 17 00:00:00 2001
Date: Thu, 6 May 2010 14:47:39 +0200

That was put in place before lxc-start started using pivot_root, so
the distro scripts can remount / without problems.

Signed-off-by: Ferenc Wagner <wferi@niif.hu>
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>