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, 2 insertions, 2 deletions

diff --git a/blockdev.c b/blockdev.c
index af4e239..dbf0251 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -653,7 +653,7 @@ int do_snapshot_blkdev(Monitor *mon, const QDict *qdict, QObject **ret_data)
         goto out;
     }
 
-    qemu_aio_flush();
+    bdrv_drain_all();
     bdrv_flush(bs);
 
     bdrv_close(bs);
@@ -840,7 +840,7 @@ int do_drive_del(Monitor *mon, const QDict *qdict, QObject **ret_data)
     }
 
     /* quiesce block driver; prevent further io */
-    qemu_aio_flush();
+    bdrv_drain_all();
     bdrv_flush(bs);
     bdrv_close(bs);