Re: [RFC PATCH 0/7] Enable exfat_get_block to support obtaining multiple clusters

[Namjae Jeon]

On Tue, Nov 18, 2025 at 5:26 PM Chi Zhiling <chizhiling@xxxxxxx> wrote:
>
> From: Chi Zhiling <chizhiling@xxxxxxxxxx>
Hi Chi,
>
> The purpose of this patchset is to prepare for adapting exfat to iomap
> in the future. Currently, the main issue preventing exfat from supporting
> iomap is its inability to fetch multiple contiguous clusters.
Do you have a plan to work iomap support for exfat ?
>
> However, this patchset does not directly modify exfat_map_cluster and
> exfat_get_cluster to support multi-clusters. Instead, after obtaining
> the first cluster, it uses exfat_count_contig_clusters to retrieve the
> subsequent contiguous clusters.
>
> This approach is the one with the fewest changes among all the solutions
> I have attempted, making the modifications easier to review.
>
> This patchset includes two main changes: one reduces the number of sb_bread
> calls when accessing adjacent clusters to save time, and the other enables
> fetching multiple contiguous entries in exfat_get_blocks.
Are there any performance improvement measurements when applying this patch-set?

Thanks.
>
> Chi Zhiling (7):
>   exfat: add cache option for __exfat_ent_get
>   exfat: support reuse buffer head for exfat_ent_get
>   exfat: reuse cache to improve exfat_get_cluster
>   exfat: improve exfat_count_num_clusters
>   exfat: improve exfat_find_last_cluster
>   exfat: introduce exfat_count_contig_clusters
>   exfat: get mutil-clusters in exfat_get_block
>
>  fs/exfat/cache.c    | 11 ++++--
>  fs/exfat/exfat_fs.h |  6 ++-
>  fs/exfat/fatent.c   | 90 ++++++++++++++++++++++++++++++++++++---------
>  fs/exfat/inode.c    | 14 ++++++-
>  4 files changed, 97 insertions(+), 24 deletions(-)
>
> --
> 2.43.0
>