linux.conf.au 2003
Create a file - cont.

static int fs_create_by_name (const char *name, mode_t mode,
                                 struct dentry *parent, struct dentry **dentry)
{
        int error = 0;

        /* If the parent is not specified, we create it in the root.
         * We need the root dentry to do this, which is in the super 
         * block. A pointer to that is in the struct vfsmount that we
         * have around.
         */
        if (!parent ) {
                if (usbfs_mount && usbfs_mount->mnt_sb) {
                        parent = usbfs_mount->mnt_sb->s_root;
                }
        }

        if (!parent) {
                dbg("Ah! can not find a parent!");
                return -EFAULT;
        }