[libvirt] [PATCHv4 2/3] openvswitch: Add utility functions for getting and setting Open vSwitch per-port data

[Michal Privoznik]

On 22.10.2012 23:30, Laine Stump wrote:
> From: Kyle Mestery <kmestery at cisco.com>
> 
> Add utility functions for Open vSwitch to both save
> per-port data before a live migration, and restore the
> per-port data after a live migration.
> 
> Signed-off-by: Kyle Mestery <kmestery at cisco.com>
> ---
>  src/libvirt_private.syms        |  2 ++
>  src/util/virnetdevopenvswitch.c | 70 +++++++++++++++++++++++++++++++++++++++++
>  src/util/virnetdevopenvswitch.h |  6 ++++
>  3 files changed, 78 insertions(+)

ACK but see my comments below

Michal

> 
> diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
> index 60f9c7f..699c9a3 100644
> --- a/src/libvirt_private.syms
> +++ b/src/libvirt_private.syms
> @@ -1500,7 +1500,9 @@ virNetDevMacVLanVPortProfileRegisterCallback;
>  
>  # virnetdevopenvswitch.h
>  virNetDevOpenvswitchAddPort;
> +virNetDevOpenvswitchGetMigrateData;
>  virNetDevOpenvswitchRemovePort;
> +virNetDevOpenvswitchSetMigrateData;
>  
>  
>  # virnetdevtap.h
> diff --git a/src/util/virnetdevopenvswitch.c b/src/util/virnetdevopenvswitch.c
> index a6993b6..841f693 100644
> --- a/src/util/virnetdevopenvswitch.c
> +++ b/src/util/virnetdevopenvswitch.c
> @@ -179,3 +179,73 @@ int virNetDevOpenvswitchRemovePort(const char *brname ATTRIBUTE_UNUSED, const ch
>          virCommandFree(cmd);
>          return ret;
>  }
> +
> +/**
> + * virNetDevOpenvswitchGetMigrateData:
> + * @migrate: a pointer to store the data into, allocated by this function
> + * @ifname: name of the interface for which data is being migrated
> + *
> + * Allocates data to be migrated specific to Open vSwitch
> + *
> + * Returns 0 in case of success or -1 in case of failure
> + */
> +int virNetDevOpenvswitchGetMigrateData(char **migrate, const char *ifname)
> +{
> +    virCommandPtr cmd = NULL;
> +    int ret = 0;
> +
> +    cmd = virCommandNewArgList(OVSVSCTL, "--timeout=5", "get", "Interface",
> +                               ifname, "external_ids:PortData", NULL);
> +
> +    virCommandSetOutputBuffer(cmd, migrate);
> +
> +    /* Run the command */
> +    if (virCommandRun(cmd, NULL) < 0) {
> +        virReportSystemError(VIR_ERR_INTERNAL_ERROR,
> +                             _("Unable to run command to get OVS port data for "
> +                             "interface %s"), ifname);
> +        ret = -1;
> +        goto error;
> +    }
> +
> +    /* Wipeout the newline */
> +    (*migrate)[strlen(*migrate) - 1] = '\0';
> +
> +error:
> +    return ret;
> +}
> +
> +/**
> + * virNetDevOpenvswitchSetMigrateData:
> + * @migrate: the data which was transferred during migration
> + * @ifname: the name of the interface the data is associated with
> + *
> + * Repopulates OVS per-port data on destination host
> + *
> + * Returns 0 in case of success or -1 in case of failure
> + */
> +int virNetDevOpenvswitchSetMigrateData(char *migrate, const char *ifname)
> +{
> +    virCommandPtr cmd = NULL;
> +    int ret = 0;
> +    virBufferPtr buf;
> +
> +    if (VIR_ALLOC(buf) < 0) {
> +        ret = -1;
> +        goto error;
> +    }

I think we miss virReportOOMError() in here.

> +
> +    virBufferAsprintf(buf, "external_ids:PortData=%s", migrate);


> +
> +    cmd = virCommandNewArgList(OVSVSCTL, "--timeout=5", "set", "Interface", ifname,
> +                               virBufferCurrentContent(buf), NULL);

Again, if we ran OOM virBuffer* will return NULL. It should be checked.

> +    /* Run the command */
> +    if ((ret = virCommandRun(cmd, NULL)) < 0) {
> +        virReportSystemError(VIR_ERR_INTERNAL_ERROR,
> +                             _("Unable to run command to set OVS port data for "
> +                             "interface %s"), ifname);
> +    }
> +
> +error:
> +    return ret;
> +}
> diff --git a/src/util/virnetdevopenvswitch.h b/src/util/virnetdevopenvswitch.h
> index 7e5b618..147cd6f 100644
> --- a/src/util/virnetdevopenvswitch.h
> +++ b/src/util/virnetdevopenvswitch.h
> @@ -42,4 +42,10 @@ int virNetDevOpenvswitchAddPort(const char *brname,
>  int virNetDevOpenvswitchRemovePort(const char *brname, const char *ifname)
>      ATTRIBUTE_NONNULL(2) ATTRIBUTE_RETURN_CHECK;
>  
> +int virNetDevOpenvswitchGetMigrateData(char **migrate, const char *ifname)
> +    ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2) ATTRIBUTE_RETURN_CHECK;
> +
> +int virNetDevOpenvswitchSetMigrateData(char *migrate, const char *ifname)
> +    ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2) ATTRIBUTE_RETURN_CHECK;
> +
>  #endif /* __VIR_NETDEV_OPENVSWITCH_H__ */
>