nilfs2: use iget for all metadata files

This makes use of iget5_locked to allocate or get inode for metadata
files to stop using own inode allocator.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
diff --git a/fs/nilfs2/ifile.h b/fs/nilfs2/ifile.h
index cbca32e..59b6f2b 100644
--- a/fs/nilfs2/ifile.h
+++ b/fs/nilfs2/ifile.h
@@ -49,6 +49,8 @@
 int nilfs_ifile_delete_inode(struct inode *, ino_t);
 int nilfs_ifile_get_inode_block(struct inode *, ino_t, struct buffer_head **);
 
-struct inode *nilfs_ifile_new(struct nilfs_sb_info *sbi, size_t inode_size);
+int nilfs_ifile_read(struct super_block *sb, struct nilfs_root *root,
+		     size_t inode_size, struct nilfs_inode *raw_inode,
+		     struct inode **inodep);
 
 #endif	/* _NILFS_IFILE_H */