diff mbox series

[PULL,06/10] block: Expect graph changes in bdrv_parent_drained_begin/end

Message ID 20171129152628.14906-7-kwolf@redhat.com
State New
Headers show
Series [PULL,01/10] iotests: fix 075 and 078 | expand

Commit Message

Kevin Wolf Nov. 29, 2017, 3:26 p.m. UTC 
The .drained_begin/end callbacks can (directly or indirectly via
aio_poll()) cause block nodes to be removed or the current BdrvChild to
point to a different child node.

Use QLIST_FOREACH_SAFE() to make sure we don't access invalid
BlockDriverStates or accidentally continue iterating the parents of the
new child node instead of the node we actually came from.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Tested-by: Jeff Cody <jcody@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Jeff Cody <jcody@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 block/io.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)
diff mbox series

Patch

diff --git a/block/io.c b/block/io.c
index 4fdf93a014..6773926fc1 100644
--- a/block/io.c
+++ b/block/io.c
@@ -42,9 +42,9 @@  static int coroutine_fn bdrv_co_do_pwrite_zeroes(BlockDriverState *bs,
 
 void bdrv_parent_drained_begin(BlockDriverState *bs)
 {
-    BdrvChild *c;
+    BdrvChild *c, *next;
 
-    QLIST_FOREACH(c, &bs->parents, next_parent) {
+    QLIST_FOREACH_SAFE(c, &bs->parents, next_parent, next) {
         if (c->role->drained_begin) {
             c->role->drained_begin(c);
         }
@@ -53,9 +53,9 @@  void bdrv_parent_drained_begin(BlockDriverState *bs)
 
 void bdrv_parent_drained_end(BlockDriverState *bs)
 {
-    BdrvChild *c;
+    BdrvChild *c, *next;
 
-    QLIST_FOREACH(c, &bs->parents, next_parent) {
+    QLIST_FOREACH_SAFE(c, &bs->parents, next_parent, next) {
         if (c->role->drained_end) {
             c->role->drained_end(c);
         }