Subject: Re: [vserver] autofs failing to umount in guest
From: Fog_Watch <db5@exemail.com.au>
Date: Tue, 29 Dec 2009 17:24:07 +1100

On Mon, 28 Dec 2009 16:38:26 +0100
Herbert Poetzl <herbert@13thfloor.at> wrote:

snip
> the fact that this works shows that the problem in your
> setup is probably not Linux-VServer related, as there
> should be no difference between manual umount and the
> umount autofs does ...
I don't know what it means, but there is a difference between manual
umount and the umount autofs does inside my guest:
hostname ~ # df | grep cdrom
hostname ~ # cd /mnt/cdrom
hostname cdrom # df | grep cdrom
/dev/sr0                717098    717098         0
100% /mnt/removables/cdrom 
hostname cdrom # cd ~
hostname ~ # tail /var/log/syslog | grep umount
Dec 29 11:26:41 hostname automount[10869]: umount_autofs_indirect: ask
umount returned busy /mnt/removables 
hostname ~ # umount /mnt/cdrom
hostname ~ # df | grep cdrom
hostname ~ #

The umount autofs fails when in the guest.  In the host it succeeds.
> 
snip
> means something is holding a reference to some part of
> the mount path, use fuser/lsof to identify obvious
> userspace apps, but could be something not so obvious
> (like e.g. the kernel nfs) as well

The following suggests that lsof does not find anything obvious.

hostname ~ # df | grep cdrom ; ls /mnt/cdrom ; df | grep cdrom ;
lsof /mnt 
Getting_Online.txt  docs          image.squashfs  livecd
README.txt          gentoo.efimg  isolinux        snapshots
/dev/sr0                717098    717098         0
100% /mnt/removables/cdrom 
hostname ~ #

snip

> I'd try without grsec or at least with grsec disabled
Yes, grsec disabled.

> you could simply put the autofs
> on the host and make it blend through to the guest name
> spaces ....
This is a viable option.  You say, "blend through to the guest name
spaces".  Hmmmm.  Is this a vnamespace idea?


On Mon, 28 Dec 2009 16:39:21 +0100
Herbert Poetzl <herbert@13thfloor.at> wrote:

> might help to compare kernel/automount versions?
Joe, your versions?

Regards

Fog_Watch.



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