Call blk_is_available() before using blk_bs() to obtain the root
BlockDriverState behind the BlockBackend.
Signed-off-by: Max Reitz <mre...@redhat.com>
---
blockdev.c | 15 +++++++++++----
1 file changed, 11 insertions(+), 4 deletions(-)
diff --git a/blockdev.c b/blockdev.c
index 4bd52b8..7f4470f 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -2821,7 +2821,8 @@ void qmp_change_backing_file(const char *device,
const char *backing_file,
Error **errp)
{
- BlockDriverState *bs = NULL;
+ BlockBackend *blk;
+ BlockDriverState *bs;
AioContext *aio_context;
BlockDriverState *image_bs = NULL;
Error *local_err = NULL;
@@ -2830,15 +2831,21 @@ void qmp_change_backing_file(const char *device,
int ret;
/* find the top layer BDS of the chain */
- bs = bdrv_find(device);
- if (!bs) {
+ blk = blk_by_name(device);
+ if (!blk) {
error_set(errp, QERR_DEVICE_NOT_FOUND, device);
return;
}
- aio_context = bdrv_get_aio_context(bs);
+ aio_context = blk_get_aio_context(blk);
aio_context_acquire(aio_context);
+ if (!blk_is_available(blk)) {
+ error_set(errp, QERR_DEVICE_HAS_NO_MEDIUM, device);
+ goto out;
+ }
+ bs = blk_bs(blk);
+
image_bs = bdrv_lookup_bs(NULL, image_node_name, &local_err);
if (local_err) {
error_propagate(errp, local_err);
--
2.1.0
