From: Daniel Lezcano <daniel.lezcano@free•fr>
To: Serge Hallyn <serge.hallyn@canonical•com>
Cc: netdev@vger•kernel.org, "Daniel Lezcano" <dlezcano@free•fr>,
containers@lists•linux-foundation.org,
"Stefan Bader" <stefan.bader@canonical•com>,
"Stéphane Graber" <stephane.graber@canonical•com>,
"Eric W. Biederman" <ebiederm@xmission•com>,
"Dan Kegel" <dank@kegel•com>,
lxc-users@lists•sourceforge.net
Subject: Re: [PATCH 1/1] dev_change_net_namespace: send a KOBJ_REMOVED/KOBJ_ADD
Date: Mon, 15 Oct 2012 22:14:17 +0200 [thread overview]
Message-ID: <507C6E99.7090906@free.fr> (raw)
In-Reply-To: <20121015174726.GA15435@sergelap>
On 10/15/2012 07:47 PM, Serge Hallyn wrote:
> When a new nic is created in namespace ns1, the kernel sends a KOBJ_ADD uevent
> to ns1. When the nic is moved to ns2, we only send a KOBJ_MOVE to ns2, and
> nothing to ns1.
>
> This patch changes that behavior so that when moving a nic from ns1 to ns2, we
> send a KOBJ_REMOVED to ns1 and KOBJ_ADD to ns2. (The KOBJ_MOVE is still
> sent to ns2).
>
> The effects of this can be seen when starting and stopping containers in
> an upstart based host. Lxc will create a pair of veth nics, the kernel
> sends KOBJ_ADD, and upstart starts network-instance jobs for each. When
> one nic is moved to the container, because no KOBJ_REMOVED event is
> received, the network-instance job for that veth never goes away. This
> was reported at https://bugs.launchpad.net/ubuntu/+source/lxc/+bug/1065589
> With this patch the networ-instance jobs properly go away.
>
> The other oddness solved here is that if a nic is passed into a running
> upstart-based container, without this patch no network-instance job is
> started in the container. But when the container creates a new nic
> itself (ip link add new type veth) then network-interface jobs are
> created. With this patch, behavior comes in line with a regular host.
>
> v2: also send KOBJ_ADD to new netns. There will then be a
> _MOVE event from the device_rename() call, but that should
> be innocuous.
>
> Signed-off-by: Serge Hallyn <serge.hallyn@canonical•com>
> Acked-by: "Eric W. Biederman" <ebiederm@xmission•com>
Acked-by: Daniel Lezcano <daniel.lezcano@free•fr>
> ---
> net/core/dev.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/net/core/dev.c b/net/core/dev.c
> index e2215ee..2c43aaf 100644
> --- a/net/core/dev.c
> +++ b/net/core/dev.c
> @@ -6172,6 +6172,9 @@ int dev_change_net_namespace(struct net_device *dev, struct net *net, const char
> dev_uc_flush(dev);
> dev_mc_flush(dev);
>
> + /* Send a netdev-removed uevent to the old namespace */
> + kobject_uevent(&dev->dev.kobj, KOBJ_REMOVE);
> +
> /* Actually switch the network namespace */
> dev_net_set(dev, net);
>
> @@ -6183,6 +6186,9 @@ int dev_change_net_namespace(struct net_device *dev, struct net *net, const char
> dev->iflink = dev->ifindex;
> }
>
> + /* Send a netdev-add uevent to the new namespace */
> + kobject_uevent(&dev->dev.kobj, KOBJ_ADD);
> +
> /* Fixup kobjects */
> err = device_rename(&dev->dev, dev->name);
> WARN_ON(err);
prev parent reply other threads:[~2012-10-15 20:14 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-15 17:47 [PATCH 1/1] dev_change_net_namespace: send a KOBJ_REMOVED/KOBJ_ADD Serge Hallyn
2012-10-15 20:14 ` Daniel Lezcano [this message]
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