nilfs2: use i_blocksize()

Since i_blocksize() helper has been defined in fs.h, use it instead of
open-coding.

Link: http://lkml.kernel.org/r/1485184655-3895-3-git-send-email-konishi.ryusuke@lab.ntt.co.jp
Signed-off-by: Geliang Tang <geliangtang@gmail.com>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

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);
 }
 

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)