rbd: Clear ceph_msg->bio_iter for retransmitted message

The bug can cause NULL pointer dereference in write_partial_msg_pages

Signed-off-by: Zheng Yan <zheng.z.yan@intel.com>
Reviewed-by: Alex Elder <elder@inktank.com>
(cherry picked from commit 43643528cce60ca184fe8197efa8e8da7c89a037)

1 files changed, 4 insertions, 0 deletions

diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c
index 524f4e4f598b..b332c3d76059 100644
--- a/net/ceph/messenger.c
+++ b/net/ceph/messenger.c
@@ -563,6 +563,10 @@ static void prepare_write_message(struct ceph_connection *con)
                 m->hdr.seq = cpu_to_le64(++con->out_seq);
                 m->needs_out_seq = false;
         }
+#ifdef CONFIG_BLOCK
+        else
+                m->bio_iter = NULL;
+#endif
 
         dout("prepare_write_message %p seq %lld type %d len %d+%d+%d %d pgs\n",
              m, con->out_seq, le16_to_cpu(m->hdr.type),