(测试环境Ubuntu14)
安装目标板挂载根文件系统的方法有两种(这里所说的服务端就是ubuntu,Ubuntu已经成功安装了nfs服务,并且保证服务端与目标板ping 通)
(注意开发板的linux要设置为nfs启动和配置nfs支持)
第一种:等待开发板启动之后去挂载,此时文件系统从Flash中启动,然后手动的通过命令去挂载服务端的文件系统。
一、安装
sudo apt-get install nfs-kernel-server/home/book/work *(rw,sync,no_root_squash,no_subtree_check)
或/home/book/work *(rw,sync,no_root_squash)
含义:sudo mount -t nfs localhost:/home/book/work /mnt
或
sudo mount 127.0.0.1:/home/book/work /mnt这样就把共享目录挂到了/mnt目录。
(5) 取消挂载用:
sudo umount /mnt(6) 开发板测试
如果用在嵌入式设备上挂载,要加上参数-o nolock
mount -t nfs -o nolock 192.168.1.8:/home/book/work /mnt============================================================
第二种方法:直接从nfs启动,这样服务端所生成的目标文件,目标端可以直接执行,不需要挂载
这种做法就是在u-boot启动之后,设置nfs挂载参数。首先必须掌握nfs命令。
root=/dev/nfs
This is necessary to enable the pseudo-NFS-device. Note that it's not a
real device but just a synonym to tell the kernel to use NFS instead of
a real device.
nfsroot=[:][,]
If the `nfsroot' parameter is NOT given on the command line,
the default "/tftpboot/%s" will be used.
Specifies the IP address of the NFS server.
The default address is determined by the `ip' parameter
(see below). This parameter allows the use of different
servers for IP autoconfiguration and NFS.
Name of the directory on the server to mount as root.
If there is a "%s" token in the string, it will be
replaced by the ASCII-representation of the client's
IP address.
Standard NFS options. All options are separated by commas.
The following defaults are used:
port = as given by server portmap daemon
rsize = 4096
wsize = 4096
timeo = 7
retrans = 3
acregmin = 3
acregmax = 60
acdirmin = 30
acdirmax = 60
flags = hard, nointr, noposix, cto, ac
ip=::::::
This parameter tells the kernel how to configure IP addresses of devices
and also how to set up the IP routing table. It was originally called
`nfsaddrs', but now the boot-time IP configuration works independently of
NFS, so it was renamed to `ip' and the old name remained as an alias for
compatibility reasons.
If this parameter is missing from the kernel command line, all fields are
assumed to be empty, and the defaults mentioned below apply. In general
this means that the kernel tries to configure everything using
autoconfiguration.
The parameter can appear alone as the value to the `ip'
parameter (without all the ':' characters before) in which case auto-
configuration is used.
IP address of the client.
Default: Determined using autoconfiguration.
IP address of the NFS server. If RARP is used to determine
the client address and this parameter is NOT empty only
replies from the specified server are accepted.
Only required for for NFS root. That is autoconfiguration
will not be triggered if it is missing and NFS root is not
in operation.
Default: Determined using autoconfiguration.
The address of the autoconfiguration server is used.
IP address of a gateway if the server is on a different subnet.
Default: Determined using autoconfiguration.
Netmask for local network interface. If unspecified
the netmask is derived from the client IP address assuming
classful addressing.
Default: Determined using autoconfiguration.
Name of the client. May be supplied by autoconfiguration,
but its absence will not trigger autoconfiguration.
Default: Client IP address is used in ASCII notation.
Name of network device to use.
Default: If the host only has one device, it is used.
Otherwise the device is determined using
autoconfiguration. This is done by sending
autoconfiguration requests out of all devices,
and using the device that received the first reply.
Method to use for autoconfiguration. In the case of options
which specify multiple autoconfiguration protocols,
requests are sent using all protocols, and the first one
to reply is used.
Only autoconfiguration protocols that have been compiled
into the kernel will be used, regardless of the value of
this option.
off or none: don't use autoconfiguration (default)
on or any: use any protocol available in the kernel
dhcp: use DHCP
bootp: use BOOTP
rarp: use RARP
both: use both BOOTP and RARP but not DHCP
(old option kept for backwards compatibility)
Default: any
nfs命令格式
在u-boot界面,输入print就可以显示如下参数
bootargs=noinitrd root=/dev/mtdblock3 init=/linuxrc console=ttySAC0
然后根据nfs命令格式,具体格式解析要看nfs命令介绍。
nfsroot=[:][,] ip=::::::
将启动参数设置为
set bootargs noinitrd root=/dev/nfs nfsroot=192.168.1.24:/home/linux/root_fs/first_fs/ ip=192.168.1.12:192.168.1.24:192.168.1.1:255.255.255.0::eth0:off init=/linuxrc console=ttySAC0
当文件系统启动之后,服务器端的文件会共享过来
============================================================
apt-cache search nfs这和用tftp下载一样的效果