ocfs2: use 'oi' instead of 'OCFS2_I()'

We could use 'oi' instead of 'OCFS2_I()' to make code more elegant.

Link: http://lkml.kernel.org/r/5A7020FE.5050906@huawei.com
Signed-off-by: Jun Piao <piaojun@huawei.com>
Reviewed-by: Yiwen Jiang <jiangyiwen@huawei.com>
Reviewed-by: Alex Chen <alex.chen@huawei.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Joseph Qi <jiangqi903@gmail.com>
Cc: Changwei Ge <ge.changwei@h3c.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c
index 5ff960b..302cd7c 100644
--- a/fs/ocfs2/aops.c
+++ b/fs/ocfs2/aops.c
@@ -346,7 +346,7 @@ static int ocfs2_readpage(struct file *file, struct page *page)
 	unlock = 0;
 
 out_alloc:
-	up_read(&OCFS2_I(inode)->ip_alloc_sem);
+	up_read(&oi->ip_alloc_sem);
 out_inode_unlock:
 	ocfs2_inode_unlock(inode, 0);
 out: