[libvirt] [PATCH 2/2 (v3)] util: fallback to ioctl(SIOCBRDELBR) if netlink RTM_DELLINK fails

[Laine Stump]

On 08/26/2015 09:24 PM, Michal Privoznik wrote:
> On 26.08.2015 21:05, Laine Stump wrote:
>> commit 09778e09 switched from using ioctl(SIOCBRDELBR) for bridge
>> device deletion to using a netlink RTM_DELLINK message, which is the
>> more modern way to delete a bridge (and also doesn't require the
>> bridge to be ~IFF_UP to succeed). However, although older kernels
>> (e.g. 2.6.32, in RHEL6/CentOS6) support deleting *some* link types
>> with RTM_NEWLINK, they don't support deleting bridges, and there is no
>> compile-time way to figure this out.
>>
>> This patch moves the body of the SIOCBRDELBR version of
>> virNetDevBridgeDelete() into a static function, calls the new function
>> from the original, and also calls the new function from the
>> RTM_DELLINK version if the RTM_DELLINK message generates an EOPNOTSUPP
>> error. Since RTM_DELLINK is done from the subordinate function
>> virNetlinkDelLink, which is also called for other purposes (deleting a
>> macvtap interface), a function pointer called "fallback" has been
>> added to the arglist of virNetlinkDelLink() - if that arg != NULL, the
>> provided function will be called when (and only when) RTM_DELLINK
>> fails with EOPNOTSUPP.
>>
>> Resolves:  https://bugzilla.redhat.com/show_bug.cgi?id=1252780 (part 2)
>> ---
>> Another idea for doing this I came up with during review of the others...
>>
>>  src/util/virnetdevbridge.c  | 41 ++++++++++++++++++++++++++++++-----------
>>  src/util/virnetdevmacvlan.c |  2 +-
>>  src/util/virnetlink.c       | 13 +++++++++++--
>>  src/util/virnetlink.h       |  5 ++++-
>>  4 files changed, 46 insertions(+), 15 deletions(-)
> ACK. But don't forget that the counterpart is broken too. Once you
> destroy network, on RHEL-6, you can't start it up, because of the same
> problem.

Yeah, that was patch 1/2 (which hasn't been reviewed yet (hint hint :-)