fat: simplify writeback_inode()

{

	int ret;

	struct address_space *mapping = inode->i_mapping;

	struct writeback_control wbc = {

	       .sync_mode = WB_SYNC_NONE,

	      .nr_to_write = 0,

	};

	/* if we used WB_SYNC_ALL, sync_inode waits for the io for the

	* inode to finish.  So WB_SYNC_NONE is sent down to sync_inode

	/* if we used wait=1, sync_inode_metadata waits for the io for the

	* inode to finish.  So wait=0 is sent down to sync_inode_metadata

	* and filemap_fdatawrite is used for the data blocks

	*/

	ret = sync_inode(inode, &wbc);

	ret = sync_inode_metadata(inode, 0);

	if (!ret)

	       ret = filemap_fdatawrite(mapping);

		ret = filemap_fdatawrite(inode->i_mapping);

	return ret;

}