centos5.6的mkdir -p指令疑问

[ylp@ylp ~]$ ls -F
bestylp/  betterylp/  cal2038  Desktop/  lists200  nbylp/  supylp/
[ylp@ylp ~]$ cd supylp
[ylp@ylp supylp]$ pwd
/home/ylp/supylp
[ylp@ylp supylp]$ mkdir -p ~/nbylp/mumdog/babydog
mkdir: cannot create directory `/home/ylp/nbylp/mumdog': Permission denied
[ylp@ylp supylp]$

操作过程如上，显示缺少权限，求解，该如何调整ylp的权限
PS:不su - root还是ylp用户

chmod +w /home/ylp/nbylp/mumdog