block: tell drivers about an image resize

Extend the change_cb callback with a reason argument, and use it
to tell drivers about size changes.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

1 files changed, 4 insertions, 1 deletions

diff --git a/block_int.h b/block_int.h
index 12663e817d..6ebdc3eea2 100644
--- a/block_int.h
+++ b/block_int.h
@@ -153,7 +153,7 @@ struct BlockDriverState {
     int valid_key; /* if true, a valid encryption key has been set */
     int sg;        /* if true, the device is a /dev/sg* */
     /* event callback when inserting/removing */
-    void (*change_cb)(void *opaque);
+    void (*change_cb)(void *opaque, int reason);
     void *change_opaque;
 
     BlockDriver *drv; /* NULL means no media */
@@ -203,6 +203,9 @@ struct BlockDriverState {
     void *private;
 };
 
+#define CHANGE_MEDIA	0x01
+#define CHANGE_SIZE	0x02
+
 struct BlockDriverAIOCB {
     AIOPool *pool;
     BlockDriverState *bs;