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authorJeff Cody <jcody@redhat.com>2014-06-25 15:35:26 -0400
committerStefan Hajnoczi <stefanha@redhat.com>2014-07-01 10:15:34 +0200
commit4caf0fcd45db46920a6264b1621ae6adc772ef19 (patch)
tree9deef9048dfbd6a9955fcd4abec4072444b536d6 /block.c
parent7676e2c597000eff3a7233b40cca768b358f9bc9 (diff)
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block: simplify bdrv_find_base() and bdrv_find_overlay()
This simplifies the function bdrv_find_overlay(). With this change, bdrv_find_base() is just a subset of usage of bdrv_find_overlay(), so this also takes advantage of that. Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Benoit Canet <benoit@irqsave.net> Signed-off-by: Jeff Cody <jcody@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Diffstat (limited to 'block.c')
-rw-r--r--block.c45
1 files changed, 10 insertions, 35 deletions
diff --git a/block.c b/block.c
index 6856c18..c111c29 100644
--- a/block.c
+++ b/block.c
@@ -2508,32 +2508,23 @@ int bdrv_change_backing_file(BlockDriverState *bs,
*
* Returns NULL if bs is not found in active's image chain,
* or if active == bs.
+ *
+ * Returns the bottommost base image if bs == NULL.
*/
BlockDriverState *bdrv_find_overlay(BlockDriverState *active,
BlockDriverState *bs)
{
- BlockDriverState *overlay = NULL;
- BlockDriverState *intermediate;
-
- assert(active != NULL);
- assert(bs != NULL);
-
- /* if bs is the same as active, then by definition it has no overlay
- */
- if (active == bs) {
- return NULL;
+ while (active && bs != active->backing_hd) {
+ active = active->backing_hd;
}
- intermediate = active;
- while (intermediate->backing_hd) {
- if (intermediate->backing_hd == bs) {
- overlay = intermediate;
- break;
- }
- intermediate = intermediate->backing_hd;
- }
+ return active;
+}
- return overlay;
+/* Given a BDS, searches for the base layer. */
+BlockDriverState *bdrv_find_base(BlockDriverState *bs)
+{
+ return bdrv_find_overlay(bs, NULL);
}
typedef struct BlkIntermediateStates {
@@ -4326,22 +4317,6 @@ int bdrv_get_backing_file_depth(BlockDriverState *bs)
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;
-}
-
/**************************************************************/
/* async I/Os */