uClinux mounting problem

[Altera_Forum]

Hi all, 

 I got problem when trying to mount a Linux PC to a local folder of Cyclone (/var) .  Here are the steps performed :  (the kit I'm using is cyclone 1c12 eval edition)  1) Log in uClinux on Cyclone 2) Setup an IP for the Cyclone : ifconfig eth0 192.168.1.20 netmask 255.255.255.0 3) Setup the IP for the Linux PC (Assuming : 192.168.1.19) 4) In Linux PC , Setup NFS shares by opening file /etc/exports (under ROOT) and add the following command :  /home/mymnt 192.168.1.20(rw) 5) Start NFS server : $ /etc/init.d/nfs start 6) Mount the Linux PC : mount –t –n nfs 192.168.1.19:/home/mymnt /var  After completing 6) , the following error occurred :   can't create lock file /etc/mtab~25: read-only file system (use -n flag to override)  I think the cause of the error is /etc folder (on cyclone) is READ-ONLY , so , uClinux cannot create mtab~25 on it. How can I "forward" the creation of mtab~25 to a writable folder such as /var , /usr ?   Thanks,  OneNet

[Altera_Forum]

Hi OneNet, 

 Add an empty file: /etc/mtab to your file system -- then try again -- this was all I needed.  Regards, --Scott

[Altera_Forum]

Hi Scott, 

 As I mentioned , the folder /etc on Cycloneis READ-ONLY.  (mtab~25 is created at runtime)  Thank you so much,  OneNet

[Altera_Forum]

As the mount command told you: add the -n flag to your mount command. That way it doesn't try to write to the /etc/mtab file but mounts anyway.

[Altera_Forum]

Hi Onenet, 

 > As I mentioned , the folder /etc on Cycloneis READ-ONLY.  And as I mentioned, adding /etc/mtab to the filesystem worked for me. The problem I observed was related to locking /etc/mtab. The fact that the filesystem was readonly was irrelevant.  Regards, --Scott

[Altera_Forum]

Hi wqoossens , 

 I already used -n flag in the above commands.  Regards,  OneNet

[Altera_Forum]

Hi Scott , 

 I added mtab and fstab to /etc of the Cyclone uClinux filesystem (I added fstab since if I I had added mtab ONLY , uClinux would have asked me for fstab)  Here are the contents of both mtab and fstab :  portmap:192.168.1.19  lockd:192.168.1.19 rquotad:192.168.1.19 mountd:192.168.1.19 statd:192.168.1.19  where 192.168.1.19 is the IP of Linux PC  I think these files set the connection TO the Linux PC we want to mount. (?????)  Also , I have added a step :   4a) In Linux PC , open /etc/hosts.allow as ROOT and add the following to the file :  portmap:192.168.1.20 lockd:192.168.1.20 mountd:192.168.1.20 statd:192.168.1.20  where 192.168.1.20 is the Cyclone IP  (the content of hosts.allow accepts the connection from the machines in the list)  At step 6), run the command :  mount 192.168.1.19:/home/mymnt /var  The following error occurred :  mount: rpc: port mapper failure - rpc: unable to receive  About this error , I thaught that I "opened" connection between Linux PC (/etc/hosts.allow) and Cyclone (fstab , mtab). Do I have a lack of some step ?  What do you think ?  OneNet

[Altera_Forum]

Hi OneNet, 

 The last time I checked, portmap was not included. You might want to see the following:  http://www.niosforum.com/forum/index.php?a...2355&hl=portmap (http://www.niosforum.com/forum/index.php?act=st&f=18&t=2355&hl=portmap) http://www.niosforum.com/forum/index.php?a...1543&hl=portmap (http://www.niosforum.com/forum/index.php?act=st&f=18&t=1543&hl=portmap)  Regards, --Scott

[Altera_Forum]

Hi Scott, 

 I have tried solutions in the 2 links from you but still not be able to mount a Linux PC.   By the way , do you know how to bring in the portmapper from the uCLinux CVS as NateCain mentioned in the second link (http://www.niosforum.com/forum/index.php?a...1543&hl=portmap) ?  Thanks,  OneNet

[Altera_Forum]

Hi Onenet, 

 > By the way , do you know how to bring in the portmapper from the uCLinux CVS  Use CVS to checkout the portmap code from the CVS repository.  Regards, --Scott