- * returns with the extent buffer spinlocked.
- *
- * This will spin and/or wait as required to take the lock, and then
- * return with the spinlock held.
- *
- * After this call, scheduling is not safe without first calling
- * btrfs_set_lock_blocking()
+ * drop a spinning read lock
+ */
+void btrfs_tree_read_unlock(struct extent_buffer *eb)
+{
+ btrfs_assert_tree_read_locked(eb);
+ WARN_ON(atomic_read(&eb->spinning_readers) == 0);
+ atomic_dec(&eb->spinning_readers);
+ atomic_dec(&eb->read_locks);
+ read_unlock(&eb->lock);
+}
+
+/*
+ * drop a blocking read lock
+ */
+void btrfs_tree_read_unlock_blocking(struct extent_buffer *eb)
+{
+ btrfs_assert_tree_read_locked(eb);
+ WARN_ON(atomic_read(&eb->blocking_readers) == 0);
+ if (atomic_dec_and_test(&eb->blocking_readers))
+ wake_up(&eb->read_lock_wq);
+ atomic_dec(&eb->read_locks);
+}
+
+/*
+ * take a spinning write lock. This will wait for both
+ * blocking readers or writers