[ovs-dev] [PATCH] bridge: When ports disappear from a datapath, add them back.
Ethan Jackson
ethan at nicira.com
Thu Apr 24 00:27:02 UTC 2014
Thanks for taking care of this.
Acked-by: Ethan Jackson <ethan at nicira.com>
On Wed, Apr 23, 2014 at 5:06 PM, Ben Pfaff <blp at nicira.com> wrote:
> Before commit 2a73b1d73d4bdb (bridge: Reconfigure in single pass.), if a
> port disappeared, for one reason or another, from a datapath, the next
> bridge reconfiguration pass would notice and, if the port was still
> configured in the database, add the port back to the datapath. That
> commit, however, removed the logic from bridge_refresh_ofp_port() that
> did that and failed to add the same logic to the replacement function
> bridge_delete_or_reconfigure_ports(). This commit fixes the problem.
>
> To see this problem on a Linux kernel system:
>
> ovs-vsctl add-br br0 # 1
> tunctl -t tap # 2
> ovs-vsctl add-port br0 tap # 3
> ovs-dpctl show # 4
> tunctl -d tap # 5
> ovs-dpctl show # 6
> tunctl -t tap # 7
> ovs-vsctl del-port tap -- add-port br0 tap # 8
> ovs-dpctl show # 9
>
> Steps 1-4 create a bridge and a tap and add it to the bridge and
> demonstrate that the tap is part of the datapath. Step 5 and 6 delete
> the tap and demonstrate that it has therefore disappeared from the
> datapath. Step 7 recreates a tap with the same name, and step 8
> forces ovs-vswitchd to reconfigure. Step 9 shows the effect of the
> fix: without the fix, the new tap is not added back to the datapath;
> with this fix, it is.
>
> Special thanks to Gurucharan Shetty <gshetty at nicira.com> for finding a
> simple reproduction case and then bisecting to find the commit that
> introduced the problem.
>
> Bug #1238467.
> Reported-by: Ronald Lee <ronaldlee at vmware.com>
> Signed-off-by: Ben Pfaff <blp at nicira.com>
> ---
> vswitchd/bridge.c | 44 +++++++++++++++++++++++++++++++++++++++++---
> 1 file changed, 41 insertions(+), 3 deletions(-)
>
> diff --git a/vswitchd/bridge.c b/vswitchd/bridge.c
> index f46d002..45a1491 100644
> --- a/vswitchd/bridge.c
> +++ b/vswitchd/bridge.c
> @@ -252,6 +252,7 @@ static bool iface_is_internal(const struct ovsrec_interface *iface,
> static const char *iface_get_type(const struct ovsrec_interface *,
> const struct ovsrec_bridge *);
> static void iface_destroy(struct iface *);
> +static void iface_destroy__(struct iface *);
> static struct iface *iface_lookup(const struct bridge *, const char *name);
> static struct iface *iface_find(const char *name);
> static struct iface *iface_from_ofp_port(const struct bridge *,
> @@ -667,6 +668,9 @@ bridge_delete_or_reconfigure_ports(struct bridge *br)
> struct ofproto_port ofproto_port;
> struct ofproto_port_dump dump;
>
> + struct sset ofproto_ports;
> + struct port *port, *port_next;
> +
> /* List of "ofp_port"s to delete. We make a list instead of deleting them
> * right away because ofproto implementations aren't necessarily able to
> * iterate through a changing list of ports in an entirely robust way. */
> @@ -676,11 +680,21 @@ bridge_delete_or_reconfigure_ports(struct bridge *br)
>
> del = NULL;
> n = allocated = 0;
> + sset_init(&ofproto_ports);
>
> + /* Main task: Iterate over the ports in 'br->ofproto' and remove the ports
> + * that are not configured in the database. (This commonly happens when
> + * ports have been deleted, e.g. with "ovs-vsctl del-port".)
> + *
> + * Side tasks: Reconfigure the ports that are still in 'br'. Delete ports
> + * that have the wrong OpenFlow port number (and arrange to add them back
> + * with the correct OpenFlow port number). */
> OFPROTO_PORT_FOR_EACH (&ofproto_port, &dump, br->ofproto) {
> ofp_port_t requested_ofp_port;
> struct iface *iface;
>
> + sset_add(&ofproto_ports, ofproto_port.name);
> +
> iface = iface_lookup(br, ofproto_port.name);
> if (!iface) {
> /* No such iface is configured, so we should delete this
> @@ -746,11 +760,37 @@ bridge_delete_or_reconfigure_ports(struct bridge *br)
> iface_destroy(iface);
> del = add_ofp_port(ofproto_port.ofp_port, del, &n, &allocated);
> }
> -
> for (i = 0; i < n; i++) {
> ofproto_port_del(br->ofproto, del[i]);
> }
> free(del);
> +
> + /* Iterate over this module's idea of interfaces in 'br'. Remove any ports
> + * that we didn't see when we iterated through the datapath, i.e. ports
> + * that disappeared underneath use. This is an unusual situation, but it
> + * can happen in some cases:
> + *
> + * - An admin runs a command like "ovs-dpctl del-port" (which is a bad
> + * idea but could happen).
> + *
> + * - The port represented a device that disappeared, e.g. a tuntap
> + * device destroyed via "tunctl -d", a physical Ethernet device
> + * whose module was just unloaded via "rmmod", or a virtual NIC for a
> + * VM whose VM was just terminated. */
> + HMAP_FOR_EACH_SAFE (port, port_next, hmap_node, &br->ports) {
> + struct iface *iface, *iface_next;
> +
> + LIST_FOR_EACH_SAFE (iface, iface_next, port_elem, &port->ifaces) {
> + if (!sset_contains(&ofproto_ports, iface->name)) {
> + iface_destroy__(iface);
> + }
> + }
> +
> + if (list_is_empty(&port->ifaces)) {
> + port_destroy(port);
> + }
> + }
> + sset_destroy(&ofproto_ports);
> }
>
> static void
> @@ -3145,8 +3185,6 @@ bridge_configure_dp_desc(struct bridge *br)
>
> /* Port functions. */
>
> -static void iface_destroy__(struct iface *);
> -
> static struct port *
> port_create(struct bridge *br, const struct ovsrec_port *cfg)
> {
> --
> 1.7.10.4
>
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