block: Allow bdrv_flush to return errors

This changes bdrv_flush to return 0 on success and -errno in case of failure.
It's a requirement for implementing proper error handle in users of bdrv_flush.

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

1 files changed, 1 insertions, 1 deletions

diff --git a/block.h b/block.h
index a4facf2fa6..78ecfac343 100644
--- a/block.h
+++ b/block.h
@@ -142,7 +142,7 @@ BlockDriverAIOCB *bdrv_aio_ioctl(BlockDriverState *bs,
         BlockDriverCompletionFunc *cb, void *opaque);
 
 /* Ensure contents are flushed to disk.  */
-void bdrv_flush(BlockDriverState *bs);
+int bdrv_flush(BlockDriverState *bs);
 void bdrv_flush_all(void);
 void bdrv_close_all(void);