[Qemu-devel] [PATCH] vvfat: Fix qcow write target driver specification

[Max Reitz <mreitz@redhat.com>]

First, bdrv_open_child() expects all options for the child to be
prefixed by the child's name (and a separating dot). Second,
bdrv_open_child() does not take ownership of the QDict passed to it but
only extracts all options for the child, so if a QDict is created for
the sole purpose of passing it to bdrv_open_child(), it needs to be
freed afterwards.

This patch makes vvfat adhere to both of these rules.

Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 block/vvfat.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/block/vvfat.c b/block/vvfat.c
index c3f24c6..ba2620f 100644
--- a/block/vvfat.c
+++ b/block/vvfat.c
@@ -3018,9 +3018,10 @@ static int enable_write_target(BlockDriverState *bs, Error **errp)
     }
 
     options = qdict_new();
-    qdict_put(options, "driver", qstring_from_str("qcow"));
+    qdict_put(options, "write-target.driver", qstring_from_str("qcow"));
     s->qcow = bdrv_open_child(s->qcow_filename, options, "write-target", bs,
                               &child_vvfat_qcow, false, errp);
+    QDECREF(options);
     if (!s->qcow) {
         ret = -EINVAL;
         goto err;
-- 
2.9.0