From ab588c279b2632e189c75ef44d76720d1429fe4c Mon Sep 17 00:00:00 2001
From: Bahadir Balban <bbalban@b-labs.co.uk>
Date: Wed, 16 Apr 2008 00:04:54 +0100
Subject: [PATCH] Fixed the component-consumption-every-lookup problem.

Now components only consumed on child lookup recursions.
---
 tasks/fs0/include/fs.h  | 3 ++-
 tasks/fs0/include/vfs.h | 3 ++-
 tasks/fs0/src/lookup.c  | 8 ++++----
 tasks/fs0/src/vfs.c     | 4 +++-
 4 files changed, 11 insertions(+), 7 deletions(-)

diff --git a/tasks/fs0/include/fs.h b/tasks/fs0/include/fs.h
index d60f685..d2403fa 100644
--- a/tasks/fs0/include/fs.h
+++ b/tasks/fs0/include/fs.h
@@ -46,7 +46,8 @@ struct file_ops {
 /* Operations that work on vnode fields and associations between vnodes */
 struct vnode_ops {
 	vnode_op_t create;
-	struct vnode *(*lookup)(struct vnode *root, struct pathdata *pdata);
+	struct vnode *(*lookup)(struct vnode *root, struct pathdata *pdata,
+				char *component);
 	int (*readdir)(struct vnode *v);
 	int (*filldir)(void *buf, struct vnode *v, int count);
 	vnode_op_t link;
diff --git a/tasks/fs0/include/vfs.h b/tasks/fs0/include/vfs.h
index 2d24346..876181f 100644
--- a/tasks/fs0/include/vfs.h
+++ b/tasks/fs0/include/vfs.h
@@ -82,7 +82,8 @@ struct vfs_mountpoint {
 extern struct vfs_mountpoint vfs_root;
 
 int vfs_mount_root(struct superblock *sb);
-struct vnode *generic_vnode_lookup(struct vnode *thisnode, struct pathdata *p);
+struct vnode *generic_vnode_lookup(struct vnode *thisnode, struct pathdata *p,
+				   char *component);
 struct vnode *vfs_lookup_bypath(struct pathdata *p);
 struct vnode *vfs_lookup_byvnum(struct superblock *sb, unsigned long vnum);
 
diff --git a/tasks/fs0/src/lookup.c b/tasks/fs0/src/lookup.c
index b23d384..489bf7a 100644
--- a/tasks/fs0/src/lookup.c
+++ b/tasks/fs0/src/lookup.c
@@ -20,10 +20,11 @@ struct vnode *lookup_dentry_children(struct dentry *parentdir,
 {
 	struct dentry *childdir;
 	struct vnode *v;
+	char *component = pathdata_next_component(pdata);
 
 	list_for_each_entry(childdir, &parentdir->children, child)
 		if (IS_ERR(v = childdir->vnode->ops.lookup(childdir->vnode,
-							   pdata)))
+							   pdata, component)))
 			/* Means not found, continue search */
 			if ((int)v == -ENOENT)
 				continue;
@@ -38,14 +39,13 @@ struct vnode *lookup_dentry_children(struct dentry *parentdir,
 
 /* Lookup, recursive, assuming single-mountpoint */
 struct vnode *generic_vnode_lookup(struct vnode *thisnode,
-				   struct pathdata *pdata)
+				   struct pathdata *pdata,
+				   char *component)
 {
-	char *component;
 	struct dentry *d;
 	struct vnode *found;
 	int err;
 
-	component = pathdata_next_component(pdata);
 	printf("looking up: %s\n", component);
 	/* Does this path component match with any of this vnode's dentries? */
 	list_for_each_entry(d, &thisnode->dentries, vref) {
diff --git a/tasks/fs0/src/vfs.c b/tasks/fs0/src/vfs.c
index b9985b8..f2ea262 100644
--- a/tasks/fs0/src/vfs.c
+++ b/tasks/fs0/src/vfs.c
@@ -61,6 +61,7 @@ struct vnode *vfs_lookup_byvnum(struct superblock *sb, unsigned long vnum)
 struct vnode *vfs_lookup_bypath(struct pathdata *pdata)
 {
 	struct vnode *vstart;
+	char *firstcomp;
 
 	/* Do we start from root or curdir? */
 	if (pdata->root)
@@ -72,7 +73,8 @@ struct vnode *vfs_lookup_bypath(struct pathdata *pdata)
 	 * This does vfs cache + fs lookup.
 	 */
 	BUG_ON(list_empty(&pdata->list));
-	return vstart->ops.lookup(vstart, pdata);
+       	firstcomp = pathdata_next_component(pdata);
+	return vstart->ops.lookup(vstart, pdata, firstcomp);
 }
 
 int vfs_mount_root(struct superblock *sb)