block: Consider all child nodes in bdrv_requests_pending()

The function manually recursed into bs->file and bs->backing to check
whether there were any requests pending, but it ignored other children.

There's no need to special case file and backing here, so just replace
these two explicit recursions by a loop recursing for all child nodes.

Reported-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Jeff Cody <jcody@redhat.com>
Message-id: 1446029211-27148-1-git-send-email-kwolf@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

1 files changed, 8 insertions, 5 deletions

diff --git a/block/io.c b/block/io.c
index 5ac6256..8dcad3b 100644
--- a/block/io.c
+++ b/block/io.c
@@ -216,6 +216,8 @@ void bdrv_disable_copy_on_read(BlockDriverState *bs)
 /* Check if any requests are in-flight (including throttled requests) */
 bool bdrv_requests_pending(BlockDriverState *bs)
 {
+    BdrvChild *child;
+
     if (!QLIST_EMPTY(&bs->tracked_requests)) {
         return true;
     }
@@ -225,12 +227,13 @@ bool bdrv_requests_pending(BlockDriverState *bs)
     if (!qemu_co_queue_empty(&bs->throttled_reqs[1])) {
         return true;
     }
-    if (bs->file && bdrv_requests_pending(bs->file->bs)) {
-        return true;
-    }
-    if (bs->backing && bdrv_requests_pending(bs->backing->bs)) {
-        return true;
+
+    QLIST_FOREACH(child, &bs->children, next) {
+        if (bdrv_requests_pending(child->bs)) {
+            return true;
+        }
     }
+
     return false;
 }