[libvirt] [PATCH v3] util: don't fail if no PortData is found while getting migrateData

John Ferlan jferlan at redhat.com
Sat Mar 14 03:05:09 UTC 2015



On 03/04/2015 09:01 PM, zhang bo wrote:
> 
> Introduced by f6a2f97e
> 
> Problem Description:
> After multiple times of migrating a domain, which has an ovs interface with no portData set,
> with non-shared disk, nbd ports got overflowed.
> 
> The steps to reproduce the problem:
> 1 define and start a domain with its network configured as:
>     <interface type='bridge'>
>           <source bridge='br0'/>
>           <virtualport type='openvswitch'>
>           </virtualport>
>           <model type='virtio'/>
>           <driver name='vhost' queues='4'/>
>     </interface>
> 2 do not set the network's portData.
> 3 migrate(ToURI2) it with flag 91(1011011), which means:
>   VIR_MIGRATE_LIVE
>   VIR_MIGRATE_PEER2PEER
>   VIR_MIGRATE_PERSIST_DEST
>   VIR_MIGRATE_UNDEFINE_SOURCE
>   VIR_MIGRATE_NON_SHARED_DISK
> 4 migrate success, but we got an error log in libvirtd.log:
>   error : virCommandWait:2423 : internal error: Child process (ovs-vsctl --timeout=5 get Interface
>   vnet1 external_ids:PortData) unexpected exit status 1: ovs-vsctl: no key "PortData" in Interface
>   record "vnet1" column external_ids
> 5 migrate it back, migrate it , migrate it back, .......
> 6 nbd port got overflowed.
> 
> The reasons for the problem is :
> 1 virNetDevOpenvswitchGetMigrateData() takes it as wrong if no portData is available for  the ovs
>  interface of a domain. (We think it's not appropriate, as portData is just OPTIONAL)
> 2 in func qemuMigrationBakeCookie(), it fails in qemuMigrationCookieAddNetwork(), and returns with -1.
>  qemuMigrationCookieAddNBD() is not called thereafter, and mig->nbd is still NULL.
> 3 However, qemuMigrationRun() just *WARN* if qemuMigrationBakeCookie() fails, migration still successes.
>  cookie is NULL, it's not baked on the src side.
> 4 On the destination side, it would alloc a port first and then free the nbd port in COOKIE.
>  But the cookie is NULL due to qemuMigrationCookieAddNetwork() failure at src side. thus the nbd port
>  is not freed.
> 
> In this patch, we add "--if-exists" option to make ovs-vsctl not raise error if there's no portData available.
> Further more, because portData may be NULL in the cookie at the dest side, check it before setting portData.
> 
> 
> Signed-off-by: Zhou Yimin <zhouyimin at huawei.com>
> Signed-off-by: Zhang Bo <oscar.zhangbo at huawei.com>
> ---
> V1 here:
>      https://www.redhat.com/archives/libvir-list/2015-February/msg00388.html
> V2:
>    Add "--if-exists" option to ovs-vsctl cmd,  making ovs-vsctl not raise error if there's no portData
>    available. Suggested by Martin.
>    We Tested the patch, it works.
>    link: https://www.redhat.com/archives/libvir-list/2015-March/msg00104.html
> V3:
>    move V1/V2/V3 description from above the patch to here. It did not show the detailed description above
>    after apply PATCH v2.
> ---
>  src/util/virnetdevopenvswitch.c | 11 ++++++++++-
>  1 file changed, 10 insertions(+), 1 deletion(-)
> 

Looks like this is a stray... Seems to me you followed Martin's advice
from his 2nd/3rd pass on your v1... Had some issues attempting to 'git
am' the patch, but eventually found that the last diff stanza was off by
a line as if someone edited something before sending... If I change:

> @@ -241,6 +244,12 @@ int virNetDevOpenvswitchSetMigrateData(char
*migrate, const char *ifname)

to

> @@ -241,6 +244,11 @@ int virNetDevOpenvswitchSetMigrateData(char
*migrate, const char *ifname)

Then the patch applied...

In any case, ACK and I've pushed.

John
> diff --git a/src/util/virnetdevopenvswitch.c b/src/util/virnetdevopenvswitch.c
> index e5c87bb..722d0dd 100644
> --- a/src/util/virnetdevopenvswitch.c
> +++ b/src/util/virnetdevopenvswitch.c
> @@ -30,9 +30,12 @@
>  #include "virerror.h"
>  #include "virmacaddr.h"
>  #include "virstring.h"
> +#include "virlog.h"
> 
>  #define VIR_FROM_THIS VIR_FROM_NONE
> 
> +VIR_LOG_INIT("util.netdevopenvswitch");
> +
>  /**
>   * virNetDevOpenvswitchAddPort:
>   * @brname: the bridge name
> @@ -206,7 +209,7 @@ int virNetDevOpenvswitchGetMigrateData(char **migrate, const char *ifname)
>      virCommandPtr cmd = NULL;
>      int ret = -1;
> 
> -    cmd = virCommandNewArgList(OVSVSCTL, "--timeout=5", "get", "Interface",
> +    cmd = virCommandNewArgList(OVSVSCTL, "--timeout=5", "--if-exists", "get", "Interface",
>                                 ifname, "external_ids:PortData", NULL);
> 
>      virCommandSetOutputBuffer(cmd, migrate);
> @@ -241,6 +244,12 @@ int virNetDevOpenvswitchSetMigrateData(char *migrate, const char *ifname)
>      virCommandPtr cmd = NULL;
>      int ret = -1;
> 
> +    if (!migrate) {
> +        VIR_DEBUG("No OVS port data for interface %s", ifname);
> +        return 0;
> +    }
> +
>      cmd = virCommandNewArgList(OVSVSCTL, "--timeout=5", "set",
>                                 "Interface", ifname, NULL);
>      virCommandAddArgFormat(cmd, "external_ids:PortData=%s", migrate);
> 




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