On Fri, Apr 15, 2022 at 08:36:11PM +0800, Jeffle Xu wrote:
> Implement the data plane of reading data from data blobs over fscache
> for non-inline layout.
>
> Signed-off-by: Jeffle Xu <jefflexu@xxxxxxxxxxxxxxxxx>
> Reviewed-by: Gao Xiang <hsiangkao@xxxxxxxxxxxxxxxxx>
> ---
> fs/erofs/fscache.c | 51 +++++++++++++++++++++++++++++++++++++++++++++
> fs/erofs/inode.c | 4 ++++
> fs/erofs/internal.h | 2 ++
> 3 files changed, 57 insertions(+)
>
> diff --git a/fs/erofs/fscache.c b/fs/erofs/fscache.c
> index 3f00eb34ac35..b799b0fe1b67 100644
> --- a/fs/erofs/fscache.c
> +++ b/fs/erofs/fscache.c
> @@ -84,10 +84,61 @@ static int erofs_fscache_meta_readpage(struct file *data, struct page *page)
> return ret;
> }
>
> +static int erofs_fscache_readpage(struct file *file, struct page *page)
> +{
> + struct folio *folio = page_folio(page);
> + struct inode *inode = folio_mapping(folio)->host;
> + struct super_block *sb = inode->i_sb;
> + struct erofs_map_blocks map;
> + struct erofs_map_dev mdev;
> + erofs_off_t pos;
> + loff_t pstart;
> + int ret = 0;
Redundant assignment now?
> +
> + DBG_BUGON(folio_size(folio) != EROFS_BLKSIZ);
> +
> + pos = folio_pos(folio);
> + map.m_la = pos;
> +
> + ret = erofs_map_blocks(inode, &map, EROFS_GET_BLOCKS_RAW);
> + if (ret)
> + goto out_unlock;
> +
> + if (!(map.m_flags & EROFS_MAP_MAPPED)) {
> + folio_zero_range(folio, 0, folio_size(folio));
> + goto out_uptodate;
> + }
> +
> + mdev = (struct erofs_map_dev) {
> + .m_deviceid = map.m_deviceid,
> + .m_pa = map.m_pa,
> + };
> +
> + ret = erofs_map_dev(sb, &mdev);
> + if (ret)
> + goto out_unlock;
> +
> + pstart = mdev.m_pa + (pos - map.m_la);
> + ret = erofs_fscache_read_folios(mdev.m_fscache->cookie,
> + folio_mapping(folio), folio_pos(folio),
> + folio_size(folio), pstart);
> +
> +out_uptodate:
> + if (!ret)
> + folio_mark_uptodate(folio);
> +out_unlock:
> + folio_unlock(folio);
> + return ret;
> +}
> +
> static const struct address_space_operations erofs_fscache_meta_aops = {
> .readpage = erofs_fscache_meta_readpage,
> };
>
> +const struct address_space_operations erofs_fscache_access_aops = {
> + .readpage = erofs_fscache_readpage,
> +};
> +
> /*
> * Create an fscache context for data blob.
> * Return: 0 on success and allocated fscache context is assigned to @fscache,
> diff --git a/fs/erofs/inode.c b/fs/erofs/inode.c
> index e8b37ba5e9ad..8d3f56c6469b 100644
> --- a/fs/erofs/inode.c
> +++ b/fs/erofs/inode.c
> @@ -297,6 +297,10 @@ static int erofs_fill_inode(struct inode *inode, int isdir)
> goto out_unlock;
> }
> inode->i_mapping->a_ops = &erofs_raw_access_aops;
> +#ifdef CONFIG_EROFS_FS_ONDEMAND
> + if (erofs_is_fscache_mode(inode->i_sb))
> + inode->i_mapping->a_ops = &erofs_fscache_access_aops;
> +#endif
>
> out_unlock:
> erofs_put_metabuf(&buf);
> diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
> index fa488af8dfcf..c8f6ac910976 100644
> --- a/fs/erofs/internal.h
> +++ b/fs/erofs/internal.h
> @@ -639,6 +639,8 @@ int erofs_fscache_register_cookie(struct super_block *sb,
> struct erofs_fscache **fscache,
> char *name, bool need_inode);
> void erofs_fscache_unregister_cookie(struct erofs_fscache **fscache);
> +
> +extern const struct address_space_operations erofs_fscache_access_aops;
> #else
> static inline int erofs_fscache_register_fs(struct super_block *sb)
> {
> --
> 2.27.0
--
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