diff --git a/fs/nilfs2/alloc.c b/fs/nilfs2/alloc.c
index 2c90e285d7c6725089641bc2a3fcb336b35d054b..03b8ba933eb2a3dcc781eaf9e57594da5a40f48b 100644
--- a/fs/nilfs2/alloc.c
+++ b/fs/nilfs2/alloc.c
@@ -34,7 +34,7 @@
 static inline unsigned long
 nilfs_palloc_groups_per_desc_block(const struct inode *inode)
 {
-	return (1UL << inode->i_blkbits) /
+	return i_blocksize(inode) /
 		sizeof(struct nilfs_palloc_group_desc);
 }
 
diff --git a/fs/nilfs2/btree.c b/fs/nilfs2/btree.c
index 9c7ea176ab0f8816a5662ebcde53c8c529e11475..06ffa135dfa651590a7a0dc25c76d0cb632bfe94 100644
--- a/fs/nilfs2/btree.c
+++ b/fs/nilfs2/btree.c
@@ -119,7 +119,7 @@ nilfs_btree_node_set_nchildren(struct nilfs_btree_node *node, int nchildren)
 
 static int nilfs_btree_node_size(const struct nilfs_bmap *btree)
 {
-	return 1 << btree->b_inode->i_blkbits;
+	return i_blocksize(btree->b_inode);
 }
 
 static int nilfs_btree_nchildren_per_block(const struct nilfs_bmap *btree)