commit f6801b83d0e77ca025867800d805ee80f6bda938
author Jeff Cody <jcody@redhat.com> Tue Mar 27 16:30:19 2012 -0400
committer Kevin Wolf <kwolf@redhat.com> Thu Apr 05 14:54:41 2012 +0200
tree 89a2416a400c3609388128b0cc2b2d13106b4fad
parent d68dbee80e3964d9bb0ab29ad64675da148c3cac

block: bdrv_append() fixes

A few fixups for bdrv_append():

The new bs (bs_new) passed into bdrv_append() should be anonymous.  Rather
than call bdrv_make_anon() to enforce this, use an assert to catch when a caller
is passing in a bs_new that is not anonymous.

Also, the new top layer should have its backing_format reflect the original
top's format.

And last, after the swap of bs contents, the device_name will have been copied
down. This needs to be cleared to reflect the anonymity of the bs that was
pushed down.

Signed-off-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

block.c

diff --git a/block.c b/block.c
index 33630eb..b3117ef 100644
--- a/block.c
+++ b/block.c
@@ -892,14 +892,16 @@
  * This will modify the BlockDriverState fields, and swap contents
  * between bs_new and bs_top. Both bs_new and bs_top are modified.
  *
+ * bs_new is required to be anonymous.
+ *
  * This function does not create any image files.
  */
 void bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top)
 {
     BlockDriverState tmp;
 
-    /* the new bs must not be in bdrv_states */
-    bdrv_make_anon(bs_new);
+    /* bs_new must be anonymous */
+    assert(bs_new->device_name[0] == '\0');
 
     tmp = *bs_new;
 
@@ -944,11 +946,18 @@
      * swapping bs_new and bs_top contents. */
     tmp.backing_hd = bs_new;
     pstrcpy(tmp.backing_file, sizeof(tmp.backing_file), bs_top->filename);
+    bdrv_get_format(bs_top, tmp.backing_format, sizeof(tmp.backing_format));
 
     /* swap contents of the fixed new bs and the current top */
     *bs_new = *bs_top;
     *bs_top = tmp;
 
+    /* device_name[] was carried over from the old bs_top.  bs_new
+     * shouldn't be in bdrv_states, so we need to make device_name[]
+     * reflect the anonymity of bs_new
+     */
+    bs_new->device_name[0] = '\0';
+
     /* clear the copied fields in the new backing file */
     bdrv_detach_dev(bs_new, bs_new->dev);