Btrfs: Fix extent_buffer and extent_state leaks

Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/extent_map.h b/fs/btrfs/extent_map.h
index 3b3abf3..d100f7c 100644
--- a/fs/btrfs/extent_map.h
+++ b/fs/btrfs/extent_map.h
@@ -68,7 +68,9 @@
 	atomic_t refs;
 	int flags;
 	struct list_head list;
+	struct list_head leak_list;
 	struct page *first_page;
+	unsigned long alloc_addr;
 };
 
 typedef struct extent_map *(get_extent_t)(struct inode *inode,