Re: [Qemu-devel] [PATCH v5 0/4] non-blocking connect address handling cleanup

[Orit Wasserman <owasserm@redhat.com>]

On 09/24/2012 04:36 PM, Michael S. Tsirkin wrote:
> On Mon, Sep 24, 2012 at 01:11:06PM +0200, Orit Wasserman wrote:
>> Changes from v4:
>> 	- Rename ConnectHandler to NonBlockingConnectHandler
>> 	- move function comments to functions definitions
>> 	- move connect_state allocation to outside of the loop
>> 	- fix comments text
>>
>> Changes from v3:
>> 	- add missing parenthesis QEMU_SOCKET_RC_INPROGRESS macro
>> 	- remove "block" from dummy_opts
>> 	- remove in_progress from external API (inet_connect_opts and 
>> 	  inet_nonblocking_connect)
>> 	- Allocate ConnectState inside inet_connect_opts, this make the 
>> 	  structure internal to qemu-sockets.c
>> 	- fix migrate_fd_cleanup to handle invalid fd.
>> 	
>> Changes from v2:
>> 	- remove the use of getnameinfo
>> 	- remove errp for inet_connect_addr
>> 	- remove QemuOpt "block"
>> 	- fix errors in wait_for_connect 
>> 	- pass ConnectState as a parameter to allow concurrent connect ops
>>
>> getaddrinfo can give us a list of addresses, but we only try to
>> connect to the first one. If that fails we never proceed to
>> the next one.  This is common on desktop setups that often have ipv6
>> configured but not actually working.
>> A simple way to reproduce the problem is migration:
>> for the destination use -incoming tcp:0:4444, run migrate -d tcp:localhost:4444
>> migration will fail on hosts that have both IPv4 and IPV6 address for localhost.
>>
>> To fix this, refactor address resolution code and make inet_nonblocking_connect
>> retry connection with a different address.
> 
> Acked-by: Michael S. Tsirkin <mst@redhat.com>
> 
> More ideas if you feel like touching this code some more:
> - fix listen side: drop ADDRCONF hint and ideally make
>   it address independent
> - enhance error handling so async connect errors propagate to
>   monitor somehow
I working on the second :) 
> 
>> Michael S. Tsirkin (1):
>>   Refactor inet_connect_opts function
>>
>> Orit Wasserman (3):
>>   Separate inet_connect into inet_connect (blocking) and
>>     inet_nonblocking_connect
>>   Fix address handling in inet_nonblocking_connect
>>   Clear handler only for valid fd
>>
>>  migration-tcp.c |   37 ++------
>>  migration.c     |    4 +-
>>  nbd.c           |    2 +-
>>  qemu-char.c     |    2 +-
>>  qemu-sockets.c  |  279 +++++++++++++++++++++++++++++++++++++++++--------------
>>  qemu_socket.h   |   15 +++-
>>  ui/vnc.c        |    2 +-
>>  7 files changed, 237 insertions(+), 104 deletions(-)
>>
>> -- 
>> 1.7.7.6