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>

1 files changed, 26 insertions, 14 deletions

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index e3fafaf97dee..8babb1a59a0a 100644
--- 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;