2022-04-16 00:17:00

by Jingbo Xu

Subject: [PATCH v9 19/21] erofs: implement fscache-based data read for inline layout

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 <[email protected]>
---
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

2022-04-22 07:01:53

by Gao Xiang

Subject: Re: [PATCH v9 19/21] erofs: implement fscache-based data read for inline layout

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 <[email protected]>

Reviewed-by: Gao Xiang <[email protected]>

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