Disappearing dentries in linux kernel after reboot

I am trying to create chunk of vfs by kernel, this function create directories in my module. My code looks:

struct dentry   *dentry;struct path     path;int             err, lookup;lookup = LOOKUP_DIRECTORY | LOOKUP_REVAL;mode |= S_IFDIR;dentry = kern_path_create(AT_FDCWD, name, &path, lookup);if (IS_ERR(dentry)){    return PTR_ERR(dentry);}err = vfs_mkdir(d_inode(path.dentry), dentry, mode);if (err){}done_path_create(&path, dentry);return err;

Before reboot

f1 <- dir

f2 <- dir (subdir f1)

f3 <- dir (subdir f1)

After reboot vfs tree disappear in struct dentry.

f1 <- dir

To get this output i used:

err = kern_path(FULL_MAIN_DIR_NAME, LOOKUP_FOLLOW, &tmp_root);     printk(KERN_DEBUG "%s <- dir\n",tmp_root.dentry->d_name.name );    list_for_each_entry(tmp_dentry, &tmp_root.dentry->d_subdirs, d_child)    {        if (tmp_dentry->d_name.name)        {            printk(KERN_INFO "%s <- dir (subdir f1)\n", tmp_dentry->d_name.name);        }        }

But directories are still present in system, i can use them normally. In other hand, struct inode_operations attached to them are cleared too. Anybody know how to solve this problem?