Re: [PATCH v1 9/9] exfat: support multi-cluster for exfat_get_cluster

[Yuezhang.Mo@xxxxxxxx]

> @@ -243,6 +244,7 @@ int exfat_get_cluster(struct inode *inode, unsigned int cluster,
>       struct buffer_head *bh = NULL;
>       struct exfat_cache_id cid;
>       unsigned int content, fclus;
> +     unsigned int end = (*count <= 1) ? cluster : cluster + *count - 1;

In exfat_get_block,  count is set as follows:

count = EXFAT_B_TO_CLU_ROUND_UP(bh_result->b_size, sbi);

So '*count' is always greater than or equal to 1, the above condition seems unnecessary.

> --- a/fs/exfat/inode.c
> +++ b/fs/exfat/inode.c
> @@ -134,6 +134,7 @@ static int exfat_map_cluster(struct inode *inode, unsigned int clu_offset,
>       struct exfat_inode_info *ei = EXFAT_I(inode);
>       unsigned int local_clu_offset = clu_offset;
>       unsigned int num_to_be_allocated = 0, num_clusters;
> +     unsigned int hint_count = max(*count, 1);

Same as above, hint_count seems unnecessary.

> +     /*
> +      * Return on cache hit to keep the code simple.
> +      */
> +     if (fclus == cluster) {
> +             *count = cid.fcluster + cid.nr_contig - fclus + 1;
>               return 0;

If 'cid.fcluster + cid.nr_contig - fclus + 1 < *count', how about continuing to collect clusters?
The following clusters may be continuous.

> +             while (fclus < end) {
> +                     if (exfat_ent_get(sb, clu, &content, &bh))
> +                             goto err;
> +                     if (++clu != content) {
> +                             /* TODO: read ahead if content valid */
> +                             break;

The next cluster index has been read and will definitely be used.
How about add it to the cache?