nfs网络文件无法挂载，求助！

我在为开发板安装linux系统的时候碰到了一个问题一直没解决,下面是出问题时串口的信息:

drivers/rtc/hctosys.c: unable to open rtc device (rtc0)
Looking up port of RPC 100003/2 on 192.168.2.8
rpcbind: server 192.168.2.8 not responding, timed out
Root-NFS: Unable to get nfsd port number from server, using default
Looking up port of RPC 100005/1 on 192.168.2.8
rpcbind: server 192.168.2.8 not responding, timed out
Root-NFS: Unable to get mountd port number from server, using default
Root-NFS: Server returned error -101 while mounting /opt/nfsrootfs

以下是开发环境及配置:

1.PC作为nfs服务器,ubuntu14.04;

2.内核编译时已经选择了支持nfs文件系统;

3.网络连接正常,开发板(IP:192.168.2.6)可以ping到PC(IP:192.168.2.8);

4.exports文件:/opt/nfsrootfs *(rw,sync,no_root_squash,no_subtree_check)

5.nfs服务已启动,并且可以将文件系统挂载到本机的home目录下面;

网上提到可能是防火墙的原因,但是我查看服务程序列表没有看到iptables,selinux之类的防火墙服务。

我排查了好几天一直没有找出问题到底在哪里,有谁知道的请帮忙分析分析,感激不尽!

我也不懂，你可以看一下这个看看有帮助没？

http://blog.csdn.net/cs_ing/article/details/8876642

zhaopei0418 发表于 2014-7-17 10:07
我也不懂，你可以看一下这个看看有帮助没？

http://blog.csdn.net/cs_ing/article/details/8876642

感谢你的答复,但是其实rtc加载与否与nfs文件系统能否加载成功无关,我把rtc加载进来一样无法挂载rtc:
s3c-rtc s3c2410-rtc: setting system clock to 2010-03-23 00:22:58 UTC (1269303778)
Looking up port of RPC 100003/2 on 192.168.2.8
rpcbind: server 192.168.2.8 not responding, timed out
Root-NFS: Unable to get nfsd port number from server, using default
Looking up port of RPC 100005/1 on 192.168.2.8
rpcbind: server 192.168.2.8 not responding, timed out
Root-NFS: Unable to get mountd port number from server, using default
Root-NFS: Server returned error -101 while mounting /opt/nfsrootfs
VFS: Unable to mount root fs via NFS, trying floppy.
VFS: Cannot open root device "nfs" or unknown-block(2,0)