[Qemu-block] [PATCH v3 11/19] block-backend: Decrease in_flight only after callback

[Kevin Wolf]

Request callbacks can do pretty much anything, including operations that
will yield from the coroutine (such as draining the backend). In that
case, a decreased in_flight would be visible to other code and could
lead to a drain completing while the callback hasn't actually completed
yet.

Signed-off-by: Kevin Wolf <address@hidden>
Reviewed-by: Fam Zheng <address@hidden>
Reviewed-by: Max Reitz <address@hidden>
---
 block/block-backend.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/block/block-backend.c b/block/block-backend.c
index 63eb2d10cd..5e5e60ff8d 100644
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -1340,8 +1340,8 @@ static const AIOCBInfo blk_aio_em_aiocb_info = {
 static void blk_aio_complete(BlkAioEmAIOCB *acb)
 {
     if (acb->has_returned) {
-        blk_dec_in_flight(acb->rwco.blk);
         acb->common.cb(acb->common.opaque, acb->rwco.ret);
+        blk_dec_in_flight(acb->rwco.blk);
         qemu_aio_unref(acb);
     }
 }
-- 
2.13.6