[Qemu-devel] [STABLE][PATCH 06/10] block: Fix multiwrite error handling

[Kevin Wolf <kwolf@redhat.com>]

When two requests of the same multiwrite batch fail, the callback of all
requests in that batch were called twice. This could have any kind of nasty
effects, in my case it lead to use after free and eventually a segfault.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 block.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/block.c b/block.c
index 9697dc9..06e22a6 100644
--- a/block.c
+++ b/block.c
@@ -1617,7 +1617,7 @@ static void multiwrite_cb(void *opaque, int ret)
 {
     MultiwriteCB *mcb = opaque;
 
-    if (ret < 0) {
+    if (ret < 0 && !mcb->error) {
         mcb->error = ret;
         multiwrite_user_cb(mcb);
     }
-- 
1.6.6.1