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(a)huawei.com&gt; Signed-off-by: Zhang Bo <oscar.zhangbo(a)huawei.com&gt; --- 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(-) 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); -- 1.7.12.4