* Peter Xu (pet...@redhat.com) wrote:
> migrate_incoming command is previously only used when we were providing
> "-incoming defer" in the command line, to defer the incoming migration
> channel creation.
>
> However there is similar requirement when we are paused during postcopy
> migration. The old incoming channel might have been destroyed already.
> We may need another new channel for the recovery to happen.
>
> This patch leveraged the same interface, but allows the user to specify
> incoming migration channel even for paused postcopy.
>
> Meanwhile, now migration listening ports are always detached manually
> using the tag, rather than using return values of dispatchers.
>
> Signed-off-by: Peter Xu <pet...@redhat.com>
> ---
> migration/exec.c | 2 +-
> migration/fd.c | 2 +-
> migration/migration.c | 39 +++++++++++++++++++++++++++++----------
> migration/socket.c | 2 +-
> 4 files changed, 32 insertions(+), 13 deletions(-)
>
> diff --git a/migration/exec.c b/migration/exec.c
> index ef1fb4c..26fc37d 100644
> --- a/migration/exec.c
> +++ b/migration/exec.c
> @@ -49,7 +49,7 @@ static gboolean exec_accept_incoming_migration(QIOChannel
> *ioc,
> {
> migration_channel_process_incoming(ioc);
> object_unref(OBJECT(ioc));
> - return FALSE; /* unregister */
> + return TRUE; /* keep it registered */
> }
>
> /*
> diff --git a/migration/fd.c b/migration/fd.c
> index e9a548c..7d0aefa 100644
> --- a/migration/fd.c
> +++ b/migration/fd.c
> @@ -49,7 +49,7 @@ static gboolean fd_accept_incoming_migration(QIOChannel
> *ioc,
> {
> migration_channel_process_incoming(ioc);
> object_unref(OBJECT(ioc));
> - return FALSE; /* unregister */
> + return TRUE; /* keep it registered */
> }
>
> /*
> diff --git a/migration/migration.c b/migration/migration.c
> index daf356b..5812478 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -175,6 +175,17 @@ void migration_incoming_state_destroy(void)
> qemu_event_destroy(&mis->main_thread_load_event);
> }
>
> +static bool migrate_incoming_detach_listen(MigrationIncomingState *mis)
> +{
> + if (mis->listen_task_tag) {
> + /* Never fail */
> + g_source_remove(mis->listen_task_tag);
> + mis->listen_task_tag = 0;
> + return true;
> + }
> + return false;
> +}
> +
> static void migrate_generate_event(int new_state)
> {
> if (migrate_use_events()) {
> @@ -432,10 +443,9 @@ void migration_fd_process_incoming(QEMUFile *f)
>
> /*
> * When reach here, we should not need the listening port any
> - * more. We'll detach the listening task soon, let's reset the
> - * listen task tag.
> + * more. Detach the listening port explicitly.
> */
> - mis->listen_task_tag = 0;
> + migrate_incoming_detach_listen(mis);
> }
>
> /*
> @@ -1291,14 +1301,25 @@ void migrate_del_blocker(Error *reason)
> void qmp_migrate_incoming(const char *uri, Error **errp)
> {
> Error *local_err = NULL;
> - static bool once = true;
> + MigrationIncomingState *mis = migration_incoming_get_current();
>
> - if (!deferred_incoming) {
> - error_setg(errp, "For use with '-incoming defer'");
> + if (!deferred_incoming &&
> + mis->state != MIGRATION_STATUS_POSTCOPY_PAUSED) {
> + error_setg(errp, "For use with '-incoming defer'"
> + " or PAUSED postcopy migration only.");
> return;
> }
> - if (!once) {
> - error_setg(errp, "The incoming migration has already been started");
What guards against someone doing a migrate_incoming after the succesful
completion of an incoming migration?
Also with RDMA the following won't happen so I'm not quite sure what
state we're in.
When we get to non-blocking commands it's also a bit interesting - we
could be getting an accept on the main thread at just the same time
this is going down the OOB side.
Dave
> +
> + /*
> + * Destroy existing listening task if exist. Logically this should
> + * not really happen at all (for either deferred migration or
> + * postcopy migration, we should both detached the listening
> + * task). So raise an error but still we safely detach it.
> + */
> + if (migrate_incoming_detach_listen(mis)) {
> + error_report("%s: detected existing listen channel, "
> + "while it should not exist", __func__);
> + /* Continue */
> }
>
> qemu_start_incoming_migration(uri, &local_err);
> @@ -1307,8 +1328,6 @@ void qmp_migrate_incoming(const char *uri, Error **errp)
> error_propagate(errp, local_err);
> return;
> }
> -
> - once = false;
> }
>
> bool migration_is_blocked(Error **errp)
> diff --git a/migration/socket.c b/migration/socket.c
> index 6ee51ef..e3e453f 100644
> --- a/migration/socket.c
> +++ b/migration/socket.c
> @@ -154,7 +154,7 @@ static gboolean
> socket_accept_incoming_migration(QIOChannel *ioc,
> out:
> /* Close listening socket as its no longer needed */
> qio_channel_close(ioc, NULL);
> - return FALSE; /* unregister */
> + return TRUE; /* keep it registered */
> }
>
>
> --
> 2.7.4
>
>
--
Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK
