We need to release any block migrations BlockBackends on the source
before successfully completing the migration because otherwise
inactivating the images will fail (inactivation only tolerates device
BBs).

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
---
 migration/block.c | 22 +++++++++++++++++-----
 1 file changed, 17 insertions(+), 5 deletions(-)

diff --git a/migration/block.c b/migration/block.c
index 13f90d3..deb4b0e 100644
--- a/migration/block.c
+++ b/migration/block.c
@@ -673,16 +673,14 @@ static int64_t get_remaining_dirty(void)
     return dirty << BDRV_SECTOR_BITS;
 }
 
-/* Called with iothread lock taken.  */
 
-static void block_migration_cleanup(void *opaque)
+
+/* Called with iothread lock taken.  */
+static void block_migration_cleanup_bmds(void)
 {
     BlkMigDevState *bmds;
-    BlkMigBlock *blk;
     AioContext *ctx;
 
-    bdrv_drain_all();
-
     unset_dirty_tracking();
 
     while ((bmds = QSIMPLEQ_FIRST(&block_mig_state.bmds_list)) != NULL) {
@@ -700,6 +698,16 @@ static void block_migration_cleanup(void *opaque)
         g_free(bmds->aio_bitmap);
         g_free(bmds);
     }
+}
+
+/* Called with iothread lock taken.  */
+static void block_migration_cleanup(void *opaque)
+{
+    BlkMigBlock *blk;
+
+    bdrv_drain_all();
+
+    block_migration_cleanup_bmds();
 
     blk_mig_lock();
     while ((blk = QSIMPLEQ_FIRST(&block_mig_state.blk_list)) != NULL) {
@@ -843,6 +851,10 @@ static int block_save_complete(QEMUFile *f, void *opaque)
 
     qemu_put_be64(f, BLK_MIG_FLAG_EOS);
 
+    /* Make sure that our BlockBackends are gone, so that the block driver
+     * nodes can be inactivated. */
+    block_migration_cleanup_bmds();
+
     return 0;
 }
 
-- 
1.8.3.1