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/savevm.c b/savevm.c
index f53cd4c154..0443554b39 100644
--- a/savevm.c
+++ b/savevm.c
@@ -2104,7 +2104,7 @@ int load_vmstate(const char *name)
     }
 
     /* Flush all IO requests so they don't interfere with the new state.  */
-    qemu_aio_flush();
+    bdrv_drain_all();
 
     bs = NULL;
     while ((bs = bdrv_next(bs))) {