When looking for a blkdebug node (which implements debug breakpoints),
use bdrv_primary_bs() to iterate through the graph, because that is
where a blkdebug node would be.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
 block.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/block.c b/block.c
index a467b175c6..1070aa1ba9 100644
--- a/block.c
+++ b/block.c
@@ -5218,7 +5218,7 @@ int bdrv_debug_breakpoint(BlockDriverState *bs, const char *event,
                           const char *tag)
 {
     while (bs && bs->drv && !bs->drv->bdrv_debug_breakpoint) {
-        bs = bs->file ? bs->file->bs : NULL;
+        bs = bdrv_primary_bs(bs);
     }
 
     if (bs && bs->drv && bs->drv->bdrv_debug_breakpoint) {
@@ -5231,7 +5231,7 @@ int bdrv_debug_breakpoint(BlockDriverState *bs, const char *event,
 int bdrv_debug_remove_breakpoint(BlockDriverState *bs, const char *tag)
 {
     while (bs && bs->drv && !bs->drv->bdrv_debug_remove_breakpoint) {
-        bs = bs->file ? bs->file->bs : NULL;
+        bs = bdrv_primary_bs(bs);
     }
 
     if (bs && bs->drv && bs->drv->bdrv_debug_remove_breakpoint) {
@@ -5244,7 +5244,7 @@ int bdrv_debug_remove_breakpoint(BlockDriverState *bs, const char *tag)
 int bdrv_debug_resume(BlockDriverState *bs, const char *tag)
 {
     while (bs && (!bs->drv || !bs->drv->bdrv_debug_resume)) {
-        bs = bs->file ? bs->file->bs : NULL;
+        bs = bdrv_primary_bs(bs);
     }
 
     if (bs && bs->drv && bs->drv->bdrv_debug_resume) {
@@ -5257,7 +5257,7 @@ int bdrv_debug_resume(BlockDriverState *bs, const char *tag)
 bool bdrv_debug_is_suspended(BlockDriverState *bs, const char *tag)
 {
     while (bs && bs->drv && !bs->drv->bdrv_debug_is_suspended) {
-        bs = bs->file ? bs->file->bs : NULL;
+        bs = bdrv_primary_bs(bs);
     }
 
     if (bs && bs->drv && bs->drv->bdrv_debug_is_suspended) {
-- 
2.21.0