erofs: implement fscache-based data read for non-inline layout

Implement the data plane of reading data from data blobs over fscache
for non-inline layout.

Signed-off-by: Jeffle Xu <jefflexu@linux.alibaba.com>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20220425122143.56815-19-jefflexu@linux.alibaba.com
Acked-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>

diff --git a/fs/erofs/fscache.c b/fs/erofs/fscache.c
index 23d7e862eed80429ce03ed939ab2096772b955b5..b3af72af7c888196609ecc0cc8c67b118b06341d 100644 (file)
--- a/fs/erofs/fscache.c
+++ b/fs/erofs/fscache.c
@@ -83,10 +83,61 @@ out:
        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;
+
+       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,
+};
+
 int erofs_fscache_register_cookie(struct super_block *sb,
                                  struct erofs_fscache **fscache,
                                  char *name, bool need_inode)

diff --git a/fs/erofs/inode.c b/fs/erofs/inode.c
index 6c28ed75dc82b04e920ef46d4169282b2555cac9..bcc8335b46b3a202752f098d116894aa02c485ee 100644 (file)
--- a/fs/erofs/inode.c
+++ b/fs/erofs/inode.c
@@ -292,6 +292,10 @@ 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 6459ffecf1968a94e8cfc1f0f6f4238733add59e..cfee49d33b95a0b5ce4665af3320a90cc32df45f 100644 (file)
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -614,6 +614,8 @@ 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)
 {