[Bug 1216853] Re: During PXE booting failed to mount nfs directory

[Daniel Manrique]

I think the problem is that the initrd doesn't contain the required nfs
modules, owing to a different organization of these in the 3.8 kernel
vs. the 3.5 one we had on 12.04.2.

On 12.04.2, a single nfs.ko module handles everything, this lives in
/lib/modules/<kernel-version>/kernel/fs/nfs.

On 12.04.3, if I boot a live environment from USB stick, the mentioned
directory contains several modules in addition to nfs.ko:

nfs.ko
nfs_layout_nfsv41_files.ko
nfsv2.ko
nfsv3.ko
nfsv4.ko

So it looks like NFS functionality is split into several modules here.
However, if I look in /lib/modules/3.8-whatever/kernel/fs/nfs from the
casper environment (say, by passing break=mount in the command line),
all I see is nfs.ko. So apparently the modules that handle the different
nfs protocols are missing, which explains why I get basic responses from
the NFS server (i.e. permission denied if I try to access a nonexistent
mount), but "Protocol not supported" when actually trying to use a
specific protocol for mounting.

Furthermore, I md5summed both nfs.kos and they are the same. I did this
because I thought perhaps the one in the initrd may have been compiled
in a different way and could include the protocol functionality within
itself. But no, they have the same checksum which means the problem is
probably that the additional nfs modules have to be explicitly mentioned
when building the initfs for the 12.04.3 image.

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https://bugs.launchpad.net/bugs/1216853

Title:
  During PXE booting failed to mount nfs directory

Status in “casper” package in Ubuntu:
  Confirmed

Bug description:
  Unable to mount nfs correctly with PXE install server, which works no
  issue with 12.04.2 and 13.04.

  Encountered this issue with 12.04.3 destkop CD image[0], both amd64
  and i386 image have the same problem.

  [0] http://releases.ubuntu.com/precise/ubuntu-12.04.3-desktop-
  amd64.iso

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