On Fri, Apr 15, 2022 at 08:36:12PM +0800, Jeffle Xu wrote:
> Implement the data plane of reading data from data blobs over fscache
> for inline layout.
>
> For the heading non-inline part, the data plane for non-inline layout is
> reused, while only the tail packing part needs special handling.
>
> Signed-off-by: Jeffle Xu <jefflexu@xxxxxxxxxxxxxxxxx>
Reviewed-by: Gao Xiang <hsiangkao@xxxxxxxxxxxxxxxxx>
Thanks,
Gao Xiang
> ---
> fs/erofs/fscache.c | 32 ++++++++++++++++++++++++++++++++
> 1 file changed, 32 insertions(+)
>
> diff --git a/fs/erofs/fscache.c b/fs/erofs/fscache.c
> index b799b0fe1b67..08849c15500f 100644
> --- a/fs/erofs/fscache.c
> +++ b/fs/erofs/fscache.c
> @@ -84,6 +84,33 @@ static int erofs_fscache_meta_readpage(struct file *data, struct page *page)
> return ret;
> }
>
> +static int erofs_fscache_readpage_inline(struct folio *folio,
> + struct erofs_map_blocks *map)
> +{
> + struct super_block *sb = folio_mapping(folio)->host->i_sb;
> + struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
> + erofs_blk_t blknr;
> + size_t offset, len;
> + void *src, *dst;
> +
> + /* For tail packing layout, the offset may be non-zero. */
> + offset = erofs_blkoff(map->m_pa);
> + blknr = erofs_blknr(map->m_pa);
> + len = map->m_llen;
> +
> + src = erofs_read_metabuf(&buf, sb, blknr, EROFS_KMAP);
> + if (IS_ERR(src))
> + return PTR_ERR(src);
> +
> + dst = kmap_local_folio(folio, 0);
> + memcpy(dst, src + offset, len);
> + memset(dst + len, 0, PAGE_SIZE - len);
> + kunmap_local(dst);
> +
> + erofs_put_metabuf(&buf);
> + return 0;
> +}
> +
> static int erofs_fscache_readpage(struct file *file, struct page *page)
> {
> struct folio *folio = page_folio(page);
> @@ -109,6 +136,11 @@ static int erofs_fscache_readpage(struct file *file, struct page *page)
> goto out_uptodate;
> }
>
> + if (map.m_flags & EROFS_MAP_META) {
> + ret = erofs_fscache_readpage_inline(folio, &map);
> + goto out_uptodate;
> + }
> +
> mdev = (struct erofs_map_dev) {
> .m_deviceid = map.m_deviceid,
> .m_pa = map.m_pa,
> --
> 2.27.0
