+static int ocfs2_direct_IO_zero_extend(struct ocfs2_super *osb,
+ struct inode *inode, loff_t offset,
+ u64 zero_len, int cluster_align)
+{
+ u32 p_cpos = 0;
+ u32 v_cpos = ocfs2_bytes_to_clusters(osb->sb, i_size_read(inode));
+ unsigned int num_clusters = 0;
+ unsigned int ext_flags = 0;
+ int ret = 0;
+
+ if (offset <= i_size_read(inode) || cluster_align)
+ return 0;
+
+ ret = ocfs2_get_clusters(inode, v_cpos, &p_cpos, &num_clusters,
+ &ext_flags);
+ if (ret < 0) {
+ mlog_errno(ret);
+ return ret;
+ }
+
+ if (p_cpos && !(ext_flags & OCFS2_EXT_UNWRITTEN)) {
+ u64 s = i_size_read(inode);
+ sector_t sector = (p_cpos << (osb->s_clustersize_bits - 9)) +
+ (do_div(s, osb->s_clustersize) >> 9);
+
+ ret = blkdev_issue_zeroout(osb->sb->s_bdev, sector,
+ zero_len >> 9, GFP_NOFS, false);
+ if (ret < 0)
+ mlog_errno(ret);
+ }
+
+ return ret;
+}
+
+static int ocfs2_direct_IO_extend_no_holes(struct ocfs2_super *osb,
+ struct inode *inode, loff_t offset)
+{
+ u64 zero_start, zero_len, total_zero_len;
+ u32 p_cpos = 0, clusters_to_add;
+ u32 v_cpos = ocfs2_bytes_to_clusters(osb->sb, i_size_read(inode));
+ unsigned int num_clusters = 0;
+ unsigned int ext_flags = 0;
+ u32 size_div, offset_div;
+ int ret = 0;
+
+ {
+ u64 o = offset;
+ u64 s = i_size_read(inode);
+
+ offset_div = do_div(o, osb->s_clustersize);
+ size_div = do_div(s, osb->s_clustersize);
+ }
+
+ if (offset <= i_size_read(inode))
+ return 0;
+
+ clusters_to_add = ocfs2_bytes_to_clusters(inode->i_sb, offset) -
+ ocfs2_bytes_to_clusters(inode->i_sb, i_size_read(inode));
+ total_zero_len = offset - i_size_read(inode);
+ if (clusters_to_add)
+ total_zero_len -= offset_div;
+
+ /* Allocate clusters to fill out holes, and this is only needed
+ * when we add more than one clusters. Otherwise the cluster will
+ * be allocated during direct IO */
+ if (clusters_to_add > 1) {
+ ret = ocfs2_extend_allocation(inode,
+ OCFS2_I(inode)->ip_clusters,
+ clusters_to_add - 1, 0);
+ if (ret) {
+ mlog_errno(ret);
+ goto out;
+ }
+ }
+
+ while (total_zero_len) {
+ ret = ocfs2_get_clusters(inode, v_cpos, &p_cpos, &num_clusters,
+ &ext_flags);
+ if (ret < 0) {
+ mlog_errno(ret);
+ goto out;
+ }
+
+ zero_start = ocfs2_clusters_to_bytes(osb->sb, p_cpos) +
+ size_div;
+ zero_len = ocfs2_clusters_to_bytes(osb->sb, num_clusters) -
+ size_div;
+ zero_len = min(total_zero_len, zero_len);
+
+ if (p_cpos && !(ext_flags & OCFS2_EXT_UNWRITTEN)) {
+ ret = blkdev_issue_zeroout(osb->sb->s_bdev,
+ zero_start >> 9, zero_len >> 9,
+ GFP_NOFS, false);
+ if (ret < 0) {
+ mlog_errno(ret);
+ goto out;
+ }
+ }
+
+ total_zero_len -= zero_len;
+ v_cpos += ocfs2_bytes_to_clusters(osb->sb, zero_len + size_div);
+
+ /* Only at first iteration can be cluster not aligned.
+ * So set size_div to 0 for the rest */
+ size_div = 0;
+ }
+
+out:
+ return ret;
+}
+