block: add bdrv_find_backing_image
Add bdrv_find_backing_image: given a BlockDriverState pointer, and an id,
traverse the backing image chain to locate the id.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
diff --git a/block.c b/block.c
index 2baac95..3621d11 100644
--- a/block.c
+++ b/block.c
@@ -2595,6 +2595,24 @@
return -ENOTSUP;
}
+BlockDriverState *bdrv_find_backing_image(BlockDriverState *bs,
+ const char *backing_file)
+{
+ if (!bs->drv) {
+ return NULL;
+ }
+
+ if (bs->backing_hd) {
+ if (strcmp(bs->backing_file, backing_file) == 0) {
+ return bs->backing_hd;
+ } else {
+ return bdrv_find_backing_image(bs->backing_hd, backing_file);
+ }
+ }
+
+ return NULL;
+}
+
#define NB_SUFFIXES 4
char *get_human_readable_size(char *buf, int buf_size, int64_t size)
