block: unify flush implementations

Add coroutine support for flush and apply the same emulation that
we already do for read/write.  bdrv_aio_flush is simplified to always
go through a coroutine.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/block.h b/block.h
index e77988e49c..65c51663fa 100644
--- a/block.h
+++ b/block.h
@@ -191,6 +191,7 @@ BlockDriverAIOCB *bdrv_aio_ioctl(BlockDriverState *bs,
 
 /* Ensure contents are flushed to disk.  */
 int bdrv_flush(BlockDriverState *bs);
+int coroutine_fn bdrv_co_flush(BlockDriverState *bs);
 void bdrv_flush_all(void);
 void bdrv_close_all(void);