diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
index aedacdbf77e2345acff1127dc903fcdfe29abb47..6e5b7e4636989661e1e506993dce9f82faee3f35 100644
--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -1849,7 +1849,13 @@ int btrfs_remove_free_space(struct btrfs_block_group_cache *block_group,
 		info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
 					  1, 0);
 		if (!info) {
-			WARN_ON(1);
+			/* the tree logging code might be calling us before we
+			 * have fully loaded the free space rbtree for this
+			 * block group.  So it is possible the entry won't
+			 * be in the rbtree yet at all.  The caching code
+			 * will make sure not to put it in the rbtree if
+			 * the logging code has pinned it.
+			 */
 			goto out_lock;
 		}
 	}