Btrfs: don't export symbols

Currently the extent_map code is only for btrfs so don't export it's
symbols.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

fs/btrfs/extent_map.c

@@ -43,7 +43,6 @@ void extent_map_tree_init(struct extent_map_tree *tree, gfp_t mask)
 	tree->map.rb_node = NULL;
 	spin_lock_init(&tree->lock);
 }
-EXPORT_SYMBOL(extent_map_tree_init);
 
 /**
  * alloc_extent_map - allocate new extent map structure
@@ -64,7 +63,6 @@ struct extent_map *alloc_extent_map(gfp_t mask)
 	atomic_set(&em->refs, 1);
 	return em;
 }
-EXPORT_SYMBOL(alloc_extent_map);
 
 /**
  * free_extent_map - drop reference count of an extent_map
@@ -83,7 +81,6 @@ void free_extent_map(struct extent_map *em)
 		kmem_cache_free(extent_map_cache, em);
 	}
 }
-EXPORT_SYMBOL(free_extent_map);
 
 static struct rb_node *tree_insert(struct rb_root *root, u64 offset,
 				   struct rb_node *node)
@@ -264,7 +261,6 @@ int add_extent_mapping(struct extent_map_tree *tree,
 out:
 	return ret;
 }
-EXPORT_SYMBOL(add_extent_mapping);
 
 /* simple helper to do math around the end of an extent, handling wrap */
 static u64 range_end(u64 start, u64 len)
@@ -326,7 +322,6 @@ struct extent_map *lookup_extent_mapping(struct extent_map_tree *tree,
 out:
 	return em;
 }
-EXPORT_SYMBOL(lookup_extent_mapping);
 
 /**
  * remove_extent_mapping - removes an extent_map from the extent tree
@@ -346,4 +341,3 @@ int remove_extent_mapping(struct extent_map_tree *tree, struct extent_map *em)
 	em->in_tree = 0;
 	return ret;
 }
-EXPORT_SYMBOL(remove_extent_mapping);