block: fix snapshot on QED

QED's opaque data includes a pointer back to the BlockDriverState.
This breaks when bdrv_append shuffles data between bs_new and bs_top.
To avoid this, add a "rebind" function that tells the driver about
the new relationship between the BlockDriverState and its opaque.

The patch also adds rebind to VVFAT for completeness, even though
it is not used with live snapshots.

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

1 files changed, 10 insertions, 0 deletions

diff --git a/block.c b/block.c
index 3db84cd241..87600a54dd 100644
--- a/block.c
+++ b/block.c
@@ -949,6 +949,13 @@ void bdrv_make_anon(BlockDriverState *bs)
     bs->device_name[0] = '\0';
 }
 
+static void bdrv_rebind(BlockDriverState *bs)
+{
+    if (bs->drv && bs->drv->bdrv_rebind) {
+        bs->drv->bdrv_rebind(bs);
+    }
+}
+
 /*
  * Add new bs contents at the top of an image chain while the chain is
  * live, while keeping required fields on the top layer.
@@ -1037,6 +1044,9 @@ void bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top)
     bs_new->slice_time        = 0;
     bs_new->slice_start       = 0;
     bs_new->slice_end         = 0;
+
+    bdrv_rebind(bs_new);
+    bdrv_rebind(bs_top);
 }
 
 void bdrv_delete(BlockDriverState *bs)