ocfs2: use s_maxbytes directly in ocfs2_change_file_space()

There's no need to recalculate things via ocfs2_max_file_offset() as we've
already done that to fill s_maxbytes, so use that instead. We can also
un-export ocfs2_max_file_offset() then.
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>

fs/ocfs2/file.c

@@ -1533,7 +1533,7 @@ static int __ocfs2_change_file_space(struct file *file, struct inode *inode,
 	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
 	struct buffer_head *di_bh = NULL;
 	handle_t *handle;
-	unsigned long long max_off = ocfs2_max_file_offset(inode->i_sb->s_blocksize_bits);
+	unsigned long long max_off = inode->i_sb->s_maxbytes;
 
 	if (ocfs2_is_hard_readonly(osb) || ocfs2_is_soft_readonly(osb))
 		return -EROFS;

fs/ocfs2/super.c

@@ -319,7 +319,7 @@ static void ocfs2_destroy_inode(struct inode *inode)
 /* From xfs_super.c:xfs_max_file_offset
  * Copyright (c) 2000-2004 Silicon Graphics, Inc.
  */
-unsigned long long ocfs2_max_file_offset(unsigned int blockshift)
+static unsigned long long ocfs2_max_file_offset(unsigned int blockshift)
 {
 	unsigned int pagefactor = 1;
 	unsigned int bitshift = BITS_PER_LONG - 1;

fs/ocfs2/super.h

@@ -45,6 +45,4 @@ void __ocfs2_abort(struct super_block *sb,
 
 #define ocfs2_abort(sb, fmt, args...) __ocfs2_abort(sb, __PRETTY_FUNCTION__, fmt, ##args)
 
-unsigned long long ocfs2_max_file_offset(unsigned int blockshift);
-
 #endif /* OCFS2_SUPER_H */