FS0 compiles with the changes, also caught an unparanthesised double-statement

if clause in lookup.c

tasks/fs0/include/fs.h

@@ -84,10 +84,21 @@ struct dentry {
 	struct list_head child;		/* List of dentries with same parent */
 	struct list_head children;	/* List of children dentries */
 	struct list_head vref;		/* For vnode's dirent reference list */
+	struct list_head cache_list;	/* Dentry cache reference */
 	struct vnode *vnode;		/* The vnode associated with dirent */
 	struct dentry_ops ops;
 };
 
+/*
+ * Buffer to keep directory content. This is the only vnode content
+ * that fs0 maintains. All other file data is in mm0 page cache.
+ */
+struct dirbuf {
+	unsigned long npages;
+	int dirty;
+	u8 *buffer;
+};
+
 struct vnode {
 	unsigned long vnum;		/* Filesystem-wide unique vnode id */
 	int refcnt;			/* Reference counter */