block: helper function, to find the base image of a chain
This is a simple helper function, that will return the base image
of a given image chain.
Signed-off-by: Jeff Cody <jcody@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
diff --git a/block.c b/block.c
index 54209a5..d7a6d14 100644
--- a/block.c
+++ b/block.c
@@ -3117,6 +3117,22 @@
return 1 + bdrv_get_backing_file_depth(bs->backing_hd);
}
+BlockDriverState *bdrv_find_base(BlockDriverState *bs)
+{
+ BlockDriverState *curr_bs = NULL;
+
+ if (!bs) {
+ return NULL;
+ }
+
+ curr_bs = bs;
+
+ while (curr_bs->backing_hd) {
+ curr_bs = curr_bs->backing_hd;
+ }
+ return curr_bs;
+}
+
#define NB_SUFFIXES 4
char *get_human_readable_size(char *buf, int buf_size, int64_t size)
diff --git a/block.h b/block.h
index 8c9b424..e9249c4 100644
--- a/block.h
+++ b/block.h
@@ -207,6 +207,7 @@
BlockDriverState *base);
BlockDriverState *bdrv_find_overlay(BlockDriverState *active,
BlockDriverState *bs);
+BlockDriverState *bdrv_find_base(BlockDriverState *bs);
typedef struct BdrvCheckResult {
