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>
---
fs/erofs/fscache.c | 40 ++++++++++++++++++++++++++++++++++++++++
1 file changed, 40 insertions(+)
diff --git a/fs/erofs/fscache.c b/fs/erofs/fscache.c
index 65de1c754e80..d32cb5840c6d 100644
--- a/fs/erofs/fscache.c
+++ b/fs/erofs/fscache.c
@@ -60,6 +60,40 @@ 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 inode *inode = folio_file_mapping(folio)->host;
+ struct super_block *sb = inode->i_sb;
+ struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
+ erofs_blk_t blknr;
+ size_t offset, len;
+ void *src, *dst;
+
+ /*
+ * For inline (tail packing) layout, the offset may be non-zero, which
+ * can be calculated from corresponding physical address directly.
+ */
+ 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);
+
+ DBG_BUGON(folio_size(folio) != PAGE_SIZE);
+
+ dst = kmap(folio_page(folio, 0));
+ memcpy(dst, src + offset, len);
+ memset(dst + len, 0, PAGE_SIZE - len);
+ kunmap(folio_page(folio, 0));
+
+ erofs_put_metabuf(&buf);
+
+ return 0;
+}
+
static int erofs_fscache_readpage(struct file *file, struct page *page)
{
struct folio *folio = page_folio(page);
@@ -85,6 +119,12 @@ static int erofs_fscache_readpage(struct file *file, struct page *page)
goto out_uptodate;
}
+ /* inline readpage */
+ if (map.m_flags & EROFS_MAP_META) {
+ ret = erofs_fscache_readpage_inline(folio, &map);
+ goto out_uptodate;
+ }
+
/* no-inline readpage */
mdev = (struct erofs_map_dev) {
.m_deviceid = map.m_deviceid,
--
2.27.0
--
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