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 */

tasks/fs0/include/vfs.h

@@ -5,15 +5,8 @@
 #include <lib/malloc.h>
 #include <l4/lib/list.h>
 #include <memfs/memfs.h>
-
-/* 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 *buf;
-};
+#include <l4/macros.h>
+#include <stdio.h>
 
 extern struct list_head vnode_cache;
 extern struct list_head dentry_cache;

tasks/fs0/src/lookup.c

@@ -74,15 +74,16 @@ struct vnode *generic_vnode_lookup(struct vnode *thisnode, char *path)
 			/* Is this a directory? */
 			if (vfs_isdir(thisnode)) {
 				/* Are there any more path components? */
-				if (path)
+				if (path) {
 					/* Read directory contents */
 					if ((err = (int)d->vnode->ops.readdir(d->vnode)))
-						return err;
+						return PTR_ERR(err);
+
 					/* Search all children one level below. */
 					if ((found = lookup_dentry_children(d, path)))
 					 	/* Either found, or non-zero error */
 						return found;
-				else
+				} else
 					return thisnode;
 			} else { /* Its a file */
 				if (path) /* There's still path, but not directory */

tasks/fs0/src/memfs/vnode.c

@@ -214,7 +214,6 @@ int memfs_write_vnode(struct superblock *sb, struct vnode *v)
 int memfs_vnode_readdir(struct vnode *v)
 {
 	int err;
-	u8 *dirbuf;
 	struct memfs_dentry *memfsd;
 	struct dentry *parent = list_entry(v->dentries.next,
 					   struct dentry, vref);
@@ -224,13 +223,13 @@ int memfs_vnode_readdir(struct vnode *v)
 		return -ENOTDIR;
 
 	/* If a buffer is there, it means the directory is already read */
-	if (v->dirbuf->buffer)
+	if (v->dirbuf.buffer)
 		return 0;
 
 	/* This is as big as a page */
-	v->dirbuf->buffer = vfs_alloc_dirbuf();
-	v->dirbuf->npages = 1;
-	memfsd = dirbuf = v->dirbuf->buffer;
+	v->dirbuf.buffer = vfs_alloc_dirpage();
+	v->dirbuf.npages = 1;
+	memfsd = (struct memfs_dentry *) v->dirbuf.buffer;
 
 	/*
 	 * Fail if vnode size is bigger than a page. Since this allocation
@@ -239,7 +238,7 @@ int memfs_vnode_readdir(struct vnode *v)
 	BUG_ON(v->size > PAGE_SIZE);
 
 	/* Read memfsd contents into the buffer */
-	if ((err = v->fops.read(v, 0, 1, dirbuf)))
+	if ((err = v->fops.read(v, 0, 1, v->dirbuf.buffer)))
 		return err;
 
 	/* Read fs-specific directory entry into vnode and dentry caches. */

tasks/fs0/src/syscalls.c

@@ -50,7 +50,7 @@ int do_open(l4id_t sender, const char *pathname, int flags, unsigned int mode)
 	memcpy(pathcopy, pathname, strlen(pathname));
 
 	/* Get the vnode */
-	if (IS_ERR(v = vfs_lookup(vfs_root.pivot->sb, pathcopy)))
+	if (IS_ERR(v = vfs_lookup_bypath(vfs_root.pivot->sb, pathcopy)))
 		return (int)v;
 
 	/* Get the task */
@@ -103,7 +103,7 @@ int sys_readdir(l4id_t sender, int fd, void *buf, int count)
 	BUG_ON(!(vnum = t->fd[fd]));
 
 	/* Lookup vnode */
-	if (!(v = vfs_lookup_byvnum(vnum)))
+	if (!(v = vfs_lookup_byvnum(vfs_root.pivot->sb, vnum)))
 		return -EINVAL; /* No such vnode */
 
 	/* Ensure vnode is a directory */
@@ -118,8 +118,8 @@ int sys_readdir(l4id_t sender, int fd, void *buf, int count)
 	nbytes = (v->size <= count) ? v->size : count;
 
 	/* Do we have those bytes at hand? */
-	if (v->dirbuf->buffer && (v->dirbuf->npages * PAGE_SIZE) >= nbytes) {
-		memcpy(buf, v->dirbuf->buffer, nbytes); /* Finish the job */
+	if (v->dirbuf.buffer && (v->dirbuf.npages * PAGE_SIZE) >= nbytes) {
+		memcpy(buf, v->dirbuf.buffer, nbytes); /* Finish the job */
 		return nbytes;
 	}
 

tasks/fs0/src/vfs.c

@@ -9,6 +9,16 @@
 struct list_head vnode_cache;
 struct list_head dentry_cache;
 
+/*
+ * /
+ * /boot
+ * /boot/images/mm0.axf
+ * /boot/images/fs0.axf
+ * /boot/images/test0.axf
+ * /file.txt
+ */
+struct vfs_mountpoint vfs_root;
+
 /*
  * Vnodes in the vnode cache have 2 keys. One is their dentry names, the other
  * is their vnum. This one checks the vnode cache by the given vnum first.
@@ -21,7 +31,7 @@ struct vnode *vfs_lookup_byvnum(struct superblock *sb, unsigned long vnum)
 	int err;
 
 	/* Check the vnode cache by vnum */
-	list_for_each_entry(v, vnode_cache, cache_list)
+	list_for_each_entry(v, &vnode_cache, cache_list)
 		if (v->vnum == vnum)
 			return v;
 
@@ -36,9 +46,11 @@ struct vnode *vfs_lookup_byvnum(struct superblock *sb, unsigned long vnum)
 	/* Check the actual filesystem for the vnode */
 	v = vfs_alloc_vnode();
 	v->vnum = vnum;
-	if ((err = v->read_vnode(sb, v)) < 0) {
+
+	/* Note this only checks given superblock */
+	if ((err = sb->ops->read_vnode(sb, v)) < 0) {
 		vfs_free_vnode(v);
-		return err;
+		return PTR_ERR(err);
 	}
 
 	/* Add the vnode back to vnode cache */
@@ -68,16 +80,6 @@ struct vnode *vfs_lookup_bypath(struct superblock *sb, char *path)
 	return sb->root->ops.lookup(sb->root, path);
 }
 
-/*
- * /
- * /boot
- * /boot/images/mm0.axf
- * /boot/images/fs0.axf
- * /boot/images/test0.axf
- * /file.txt
- */
-struct vfs_mountpoint vfs_root;
-
 int vfs_mount_root(struct superblock *sb)
 {
 	/* Lookup the root vnode of this superblock */