2 files changed, 14 insertions, 6 deletions

diff --git a/blockdev.c b/blockdev.c
index 7bf88d4..a52f205 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -2584,6 +2584,7 @@ void qmp_change_backing_file(const char *device,
                              Error **errp)
 {
     BlockDriverState *bs = NULL;
+    AioContext *aio_context;
     BlockDriverState *image_bs = NULL;
     Error *local_err = NULL;
     bool ro;
@@ -2597,34 +2598,37 @@ void qmp_change_backing_file(const char *device,
         return;
     }
 
+    aio_context = bdrv_get_aio_context(bs);
+    aio_context_acquire(aio_context);
+
     image_bs = bdrv_lookup_bs(NULL, image_node_name, &local_err);
     if (local_err) {
         error_propagate(errp, local_err);
-        return;
+        goto out;
     }
 
     if (!image_bs) {
         error_setg(errp, "image file not found");
-        return;
+        goto out;
     }
 
     if (bdrv_find_base(image_bs) == image_bs) {
         error_setg(errp, "not allowing backing file change on an image "
                          "without a backing file");
-        return;
+        goto out;
     }
 
     /* even though we are not necessarily operating on bs, we need it to
      * determine if block ops are currently prohibited on the chain */
     if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_CHANGE, errp)) {
-        return;
+        goto out;
     }
 
     /* final sanity check */
     if (!bdrv_chain_contains(bs, image_bs)) {
         error_setg(errp, "'%s' and image file are not in the same chain",
                    device);
-        return;
+        goto out;
     }
 
     /* if not r/w, reopen to make r/w */
@@ -2635,7 +2639,7 @@ void qmp_change_backing_file(const char *device,
         bdrv_reopen(image_bs, open_flags | BDRV_O_RDWR, &local_err);
         if (local_err) {
             error_propagate(errp, local_err);
-            return;
+            goto out;
         }
     }
 
@@ -2655,6 +2659,9 @@ void qmp_change_backing_file(const char *device,
             error_propagate(errp, local_err); /* will preserve prior errp */
         }
     }
+
+out:
+    aio_context_release(aio_context);
 }
 
 void qmp_blockdev_add(BlockdevOptions *options, Error **errp)
diff --git a/hw/block/dataplane/virtio-blk.c b/hw/block/dataplane/virtio-blk.c
index 2548113..90ab27e 100644
--- a/hw/block/dataplane/virtio-blk.c
+++ b/hw/block/dataplane/virtio-blk.c
@@ -197,6 +197,7 @@ void virtio_blk_data_plane_create(VirtIODevice *vdev, VirtIOBlkConf *conf,
     blk_op_unblock(conf->conf.blk, BLOCK_OP_TYPE_RESIZE, s->blocker);
     blk_op_unblock(conf->conf.blk, BLOCK_OP_TYPE_DRIVE_DEL, s->blocker);
     blk_op_unblock(conf->conf.blk, BLOCK_OP_TYPE_BACKUP_SOURCE, s->blocker);
+    blk_op_unblock(conf->conf.blk, BLOCK_OP_TYPE_CHANGE, s->blocker);
     blk_op_unblock(conf->conf.blk, BLOCK_OP_TYPE_COMMIT, s->blocker);
     blk_op_unblock(conf->conf.blk, BLOCK_OP_TYPE_EJECT, s->blocker);
     blk_op_unblock(conf->conf.blk, BLOCK_OP_TYPE_INTERNAL_SNAPSHOT_DELETE,