block: convert qemu_aio_flush() calls to bdrv_drain_all()

Many places in QEMU call qemu_aio_flush() to complete all pending
asynchronous I/O.  Most of these places actually want to drain all block
requests but there is no block layer API to do so.

This patch introduces the bdrv_drain_all() API to wait for requests
across all BlockDriverStates to complete.  As a bonus we perform checks
after qemu_aio_wait() to ensure that requests really have finished.

Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/cpus.c b/cpus.c
index 82530c4a03..58e173c1d9 100644
--- a/cpus.c
+++ b/cpus.c
@@ -396,7 +396,7 @@ static void do_vm_stop(RunState state)
         pause_all_vcpus();
         runstate_set(state);
         vm_state_notify(0, state);
-        qemu_aio_flush();
+        bdrv_drain_all();
         bdrv_flush_all();
         monitor_protocol_event(QEVENT_STOP, NULL);
     }