block: Inactivate parents before children

The proper order for inactivating block nodes is that first the parents
get inactivated and then the children. If we do things in this order, we
can assert that we didn't accidentally leave a parent activated when one
of its child nodes is inactive.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>

diff --git a/block.c b/block.c
index 444a52e331c66abbaccde2a6650ed5ce2ae1a6d6..170002e78eb9bcb84d8246438ffaef826c8a094c 100644 (file)
--- a/block.c
+++ b/block.c
@@ -762,6 +762,13 @@ static void bdrv_child_cb_drained_end(BdrvChild *child)
     bdrv_drained_end(bs);
 }
 
+static int bdrv_child_cb_inactivate(BdrvChild *child)
+{
+    BlockDriverState *bs = child->opaque;
+    assert(bs->open_flags & BDRV_O_INACTIVE);
+    return 0;
+}
+
 /*
  * Returns the options and flags that a temporary snapshot should get, based on
  * the originally requested flags (the originally requested image will have
@@ -822,6 +829,7 @@ const BdrvChildRole child_file = {
     .inherit_options = bdrv_inherited_options,
     .drained_begin   = bdrv_child_cb_drained_begin,
     .drained_end     = bdrv_child_cb_drained_end,
+    .inactivate      = bdrv_child_cb_inactivate,
 };
 
 /*
@@ -843,6 +851,7 @@ const BdrvChildRole child_format = {
     .inherit_options = bdrv_inherited_fmt_options,
     .drained_begin   = bdrv_child_cb_drained_begin,
     .drained_end     = bdrv_child_cb_drained_end,
+    .inactivate      = bdrv_child_cb_inactivate,
 };
 
 static void bdrv_backing_attach(BdrvChild *c)
@@ -928,6 +937,7 @@ const BdrvChildRole child_backing = {
     .inherit_options = bdrv_backing_options,
     .drained_begin   = bdrv_child_cb_drained_begin,
     .drained_end     = bdrv_child_cb_drained_end,
+    .inactivate      = bdrv_child_cb_inactivate,
 };
 
 static int bdrv_open_flags(BlockDriverState *bs, int flags)
@@ -4029,13 +4039,6 @@ static int bdrv_inactivate_recurse(BlockDriverState *bs,
         }
     }
 
-    QLIST_FOREACH(child, &bs->children, next) {
-        ret = bdrv_inactivate_recurse(child->bs, setting_flag);
-        if (ret < 0) {
-            return ret;
-        }
-    }
-
     if (setting_flag) {
         bs->open_flags |= BDRV_O_INACTIVE;
 
@@ -4049,6 +4052,14 @@ static int bdrv_inactivate_recurse(BlockDriverState *bs,
             }
         }
     }
+
+    QLIST_FOREACH(child, &bs->children, next) {
+        ret = bdrv_inactivate_recurse(child->bs, setting_flag);
+        if (ret < 0) {
+            return ret;
+        }
+    }
+
     return 0;
 }