rbd: return ResponseMessage result from rbd_handle_request_lock()

Right now it's just 0, but "no automatic exclusive lock transfers" mode
code will need -EROFS.

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Jason Dillaman <dillaman@redhat.com>

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index e3fafaf..8babb1a 100644 (file)
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -3572,12 +3572,16 @@ static void rbd_handle_released_lock(struct rbd_device *rbd_dev, u8 struct_v,
        up_read(&rbd_dev->lock_rwsem);
 }
 
-static bool rbd_handle_request_lock(struct rbd_device *rbd_dev, u8 struct_v,
-                                   void **p)
+/*
+ * Returns result for ResponseMessage to be encoded (<= 0), or 1 if no
+ * ResponseMessage is needed.
+ */
+static int rbd_handle_request_lock(struct rbd_device *rbd_dev, u8 struct_v,
+                                  void **p)
 {
        struct rbd_client_id my_cid = rbd_get_cid(rbd_dev);
        struct rbd_client_id cid = { 0 };
-       bool need_to_send;
+       int result = 1;
 
        if (struct_v >= 2) {
                cid.gid = ceph_decode_64(p);
@@ -3587,19 +3591,30 @@ static bool rbd_handle_request_lock(struct rbd_device *rbd_dev, u8 struct_v,
        dout("%s rbd_dev %p cid %llu-%llu\n", __func__, rbd_dev, cid.gid,
             cid.handle);
        if (rbd_cid_equal(&cid, &my_cid))
-               return false;
+               return result;
 
        down_read(&rbd_dev->lock_rwsem);
-       need_to_send = __rbd_is_lock_owner(rbd_dev);
-       if (rbd_dev->lock_state == RBD_LOCK_STATE_LOCKED) {
-               if (!rbd_cid_equal(&rbd_dev->owner_cid, &rbd_empty_cid)) {
+       if (__rbd_is_lock_owner(rbd_dev)) {
+               if (rbd_dev->lock_state == RBD_LOCK_STATE_LOCKED &&
+                   rbd_cid_equal(&rbd_dev->owner_cid, &rbd_empty_cid))
+                       goto out_unlock;
+
+               /*
+                * encode ResponseMessage(0) so the peer can detect
+                * a missing owner
+                */
+               result = 0;
+
+               if (rbd_dev->lock_state == RBD_LOCK_STATE_LOCKED) {
                        dout("%s rbd_dev %p queueing unlock_work\n", __func__,
                             rbd_dev);
                        queue_work(rbd_dev->task_wq, &rbd_dev->unlock_work);
                }
        }
+
+out_unlock:
        up_read(&rbd_dev->lock_rwsem);
-       return need_to_send;
+       return result;
 }
 
 static void __rbd_acknowledge_notify(struct rbd_device *rbd_dev,
@@ -3682,13 +3697,10 @@ static void rbd_watch_cb(void *arg, u64 notify_id, u64 cookie,
                rbd_acknowledge_notify(rbd_dev, notify_id, cookie);
                break;
        case RBD_NOTIFY_OP_REQUEST_LOCK:
-               if (rbd_handle_request_lock(rbd_dev, struct_v, &p))
-                       /*
-                        * send ResponseMessage(0) back so the client
-                        * can detect a missing owner
-                        */
+               ret = rbd_handle_request_lock(rbd_dev, struct_v, &p);
+               if (ret <= 0)
                        rbd_acknowledge_notify_result(rbd_dev, notify_id,
-                                                     cookie, 0);
+                                                     cookie, ret);
                else
                        rbd_acknowledge_notify(rbd_dev, notify_id, cookie);
                break;