diff --git a/fs/btrfs/subpage.h b/fs/btrfs/subpage.h
index f3c5def..b86a488 100644
--- a/fs/btrfs/subpage.h
+++ b/fs/btrfs/subpage.h
@@ -29,6 +29,9 @@ struct btrfs_subpage {
 		 */
 		atomic_t eb_refs;
 		/* Structures only used by data */
+		struct {
+			atomic_t readers;
+		};
 	};
 };
 
@@ -53,6 +56,11 @@ void btrfs_page_inc_eb_refs(const struct btrfs_fs_info *fs_info,
 void btrfs_page_dec_eb_refs(const struct btrfs_fs_info *fs_info,
 			    struct page *page);
 
+void btrfs_subpage_start_reader(const struct btrfs_fs_info *fs_info,
+		struct page *page, u64 start, u32 len);
+void btrfs_subpage_end_reader(const struct btrfs_fs_info *fs_info,
+		struct page *page, u64 start, u32 len);
+
 /*
  * Template for subpage related operations.
  *