From: Kevin Wolf <kwolf@redhat.com>
Date: Tue, 16 Jun 2015 08:58:20 +0000 (+0200)
Subject: block: Reorder cleanups in bdrv_close()
X-Git-Tag: v2.4.0-rc1~10^2~5
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=9a7dedbc43c7c400663d2876a8ccb6d942a1429a;p=thirdparty%2Fqemu.git

block: Reorder cleanups in bdrv_close()

Block drivers may still want to access their child nodes in their
.bdrv_close handler. If they unref and/or detach a child by themselves,
this should not result in a double free.

There is additional code for backing files, which are just a special
case of child nodes. The same applies for them.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
---

diff --git a/block.c b/block.c
index b723cf28581..d5c9f032aaf 100644
--- a/block.c
+++ b/block.c
@@ -1901,6 +1901,14 @@ void bdrv_close(BlockDriverState *bs)
     if (bs->drv) {
         BdrvChild *child, *next;
 
+        bs->drv->bdrv_close(bs);
+
+        if (bs->backing_hd) {
+            BlockDriverState *backing_hd = bs->backing_hd;
+            bdrv_set_backing_hd(bs, NULL);
+            bdrv_unref(backing_hd);
+        }
+
         QLIST_FOREACH_SAFE(child, &bs->children, next, next) {
             /* TODO Remove bdrv_unref() from drivers' close function and use
              * bdrv_unref_child() here */
@@ -1910,12 +1918,6 @@ void bdrv_close(BlockDriverState *bs)
             bdrv_detach_child(child);
         }
 
-        if (bs->backing_hd) {
-            BlockDriverState *backing_hd = bs->backing_hd;
-            bdrv_set_backing_hd(bs, NULL);
-            bdrv_unref(backing_hd);
-        }
-        bs->drv->bdrv_close(bs);
         g_free(bs->opaque);
         bs->opaque = NULL;
         bs->drv = NULL;