Quick Kernel Module Action

of Kiss Coda Wiki

Word of Wisdom

You do not generally need to compile Coda kernel module yourself. It is already included with the standard Linux or NetBSD kernel. (By the way, the Coda server does not need the kernel module, only Coda clients do).

To quickly test whether you already have the module, run modprobe coda on Linux, or FIXME XXXXXXX on NetBSD. If you see an affirmative output (or no output at all), you have the module.

Sometimes you will want to compile it yourself, however. The case may be that you already have a working Coda client (tested with the included module), but you want the latest bugfixes or module source that compiles with no build-time errors on new kernels (Linux 2.6 interface changes greatly even between minor revisions, such as 2.6.x and 2.6.x+1). Or it may be that you use a Linux distribution that does not include the Coda module (such as Red Hat) – so when you have to compile the module anyway, use the latest version.

Obtaining the Module

For Linux, simply run:

    cvs -d :pserver:anonymous@coda.cs.cmu.edu:/coda-src checkout linux-coda

Compiling the Module

For Linux:

You first have to have kernel headers present on the system. The best way to check that you do (for 2.6 Linux kernels) is to do

    ls -al /lib/modules/`uname -r`/build

If that file is a directory or a symlink to an existing directory, you’re all set. If not, install your kernel headers.

In the module source (the directory you obtained from CVS in the previous step), enter the directory appropriate for your kernel, such as linux2.6, and type


The build procedure will figure everything on its own and compile the module.

If you need more help, some can be found at coda-howto-6.html.

Loading the Module

For Linux:

The compiled module will be named coda.ko (for linux 2.6…3.x) or coda.o (for older versions).

To load the coda module file into the kernel, you can run insmod coda.ko. Even better, you can copy the coda.ko module to the proper modules directory on your system, which will make it available to the command modprobe, to /etc/modules and to modutils package:

    mkdir -p /lib/modules/`uname -r`/kernel/fs/coda/
    cp coda.ko /lib/modules/`uname -r`/kernel/fs/coda/
    depmod -a

    modprobe coda

Note that the module will be tried to automatically be loaded by the venus client cache manager at startup but it is not guaranteed to succeed. So it is more reliable if you load the module yourself beforehand in some way (such as using file /etc/modules or the modprobe command).

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Last modified: Thu Jun 26 07:37:00 UTC 2014