ext4: use ext4_update_i_disksize instead of opencoded ones

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

fs/ext4/inode.c

@@ -2651,10 +2651,7 @@ static int ext4_da_write_end(struct file *file,
 	if (copied && new_i_size > EXT4_I(inode)->i_disksize) {
 		if (ext4_has_inline_data(inode) ||
 		    ext4_da_should_update_i_disksize(page, end)) {
-			down_write(&EXT4_I(inode)->i_data_sem);
-			if (new_i_size > EXT4_I(inode)->i_disksize)
-				EXT4_I(inode)->i_disksize = new_i_size;
-			up_write(&EXT4_I(inode)->i_data_sem);
+			ext4_update_i_disksize(inode, new_i_size);
 			/* We need to mark inode dirty even if
 			 * new_i_size is less that inode->i_size
 			 * bu greater than i_disksize.(hint delalloc)