Re: [PATCH v2 1/3] erofs: get compression algorithms directly on mapping

Chao Yu
2021-10-17T15:26:20Z

On 2021/10/9 4:08, Gao Xiang wrote:
> From: Gao Xiang <hsiangkao@linux.alibaba.com>
>
> Currently, z_erofs_map_blocks_iter() returns whether extents are
> compressed or not, and the decompression frontend gets the specific
> algorithms then.
>
> It works but not quite well in many aspests, for example:
> - The decompression frontend has to deal with whether extents are
> compressed or not again and lookup the algorithms if compressed.
> It's duplicated and too detailed about the on-disk mapping.
>
> - A new secondary compression head will be introduced later so that
> each file can have 2 compression algorithms at most for different
> type of data. It could increase the complexity of the decompression
> frontend if still handled in this way;
>
> - A new readmore decompression strategy will be introduced to get
> better performance for much bigger pcluster and lzma, which needs
> the specific algorithm in advance as well.
>
> Let's look up compression algorithms in z_erofs_map_blocks_iter()
> directly instead.
>
> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>

Reviewed-by: Chao Yu <chao@kernel.org>

Thanks,