[PATCH for-7.1 1/8] nbd: actually implement reply_possible safeguard

[Paolo Bonzini]

The .reply_possible field of s->requests is never set to false.  This is
not a big problem as it is only a safeguard to detect protocol errors,
but fix it anyway.

Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
---
 block/nbd.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/block/nbd.c b/block/nbd.c
index 567872ac53..6a5e410e5f 100644
--- a/block/nbd.c
+++ b/block/nbd.c
@@ -454,15 +454,16 @@ static coroutine_fn int nbd_receive_replies(BDRVNBDState 
*s, uint64_t handle)
             nbd_channel_error(s, -EINVAL);
             return -EINVAL;
         }
-        if (s->reply.handle == handle) {
-            /* We are done */
-            return 0;
-        }
         ind2 = HANDLE_TO_INDEX(s, s->reply.handle);
         if (ind2 >= MAX_NBD_REQUESTS || !s->requests[ind2].reply_possible) {
             nbd_channel_error(s, -EINVAL);
             return -EINVAL;
         }
+        s->requests[ind2].reply_possible = nbd_reply_is_structured(&s->reply);
+        if (s->reply.handle == handle) {
+            /* We are done */
+            return 0;
+        }
         nbd_recv_coroutine_wake_one(&s->requests[ind2]);
     }
 }
-- 
2.35.1