static int ocfs2_write_cluster_by_desc(struct address_space *mapping,
				       struct ocfs2_alloc_context *data_ac,
				       struct ocfs2_alloc_context *meta_ac,
				       struct ocfs2_write_ctxt *wc,
				       loff_t pos, unsigned len)
{
	int ret, i;
	loff_t cluster_off;
	unsigned int local_len = len;
	struct ocfs2_write_cluster_desc *desc;
	struct ocfs2_super *osb = OCFS2_SB(mapping->host->i_sb);

	for (i = 0; i < wc->w_clen; i++) {
		desc = &wc->w_desc[i];

		/*
		 * We have to make sure that the total write passed in
		 * doesn't extend past a single cluster.
		 */
		local_len = len;
		cluster_off = pos & (osb->s_clustersize - 1);
		if ((cluster_off + local_len) > osb->s_clustersize)
			local_len = osb->s_clustersize - cluster_off;

		ret = ocfs2_write_cluster(mapping, &desc->c_phys,
					  desc->c_new,
					  desc->c_clear_unwritten,
					  desc->c_needs_zero,
					  data_ac, meta_ac,
					  wc, desc->c_cpos, pos, local_len);
		if (ret) {
			mlog_errno(ret);
			goto out;
		}

		len -= local_len;
		pos += local_len;
	}

	ret = 0;
out:
	return ret;
}
static int ocfs2_write_cluster_by_desc(struct address_space *mapping,
				       struct ocfs2_alloc_context *data_ac,
				       struct ocfs2_alloc_context *meta_ac,
				       struct ocfs2_write_ctxt *wc,
				       loff_t pos, unsigned len)
{
	int ret, i;
	loff_t cluster_off;
	unsigned int local_len = len;
	struct ocfs2_write_cluster_desc *desc;
	struct ocfs2_super *osb = OCFS2_SB(mapping->host->i_sb);

	for (i = 0; i < wc->w_clen; i++) {
		desc = &wc->w_desc[i];

		 
		local_len = len;
		cluster_off = pos & (osb->s_clustersize - 1);
		if ((cluster_off + local_len) > osb->s_clustersize)
			local_len = osb->s_clustersize - cluster_off;

		ret = ocfs2_write_cluster(mapping, &desc->c_phys,
					  desc->c_new,
					  desc->c_clear_unwritten,
					  desc->c_needs_zero,
					  data_ac, meta_ac,
					  wc, desc->c_cpos, pos, local_len);
		if (ret) {
			mlog_errno(ret);
			goto out;
		}

		len -= local_len;
		pos += local_len;
	}

	ret = 0;
out:
	return ret;
}