misc/146162: PXE loader(8) sets nfs_opts[] = "export" causing boot error: "mount option <export> is unknown"

[Brian A. Seklecki]

>Number:         146162
>Category:       misc
>Synopsis:       PXE loader(8) sets nfs_opts[] = "export" causing boot error: "mount option <export> is unknown"
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Thu Apr 29 21:20:03 UTC 2010
>Closed-Date:
>Last-Modified:
>Originator:     Brian A. Seklecki
>Release:        FreeBSD 8/amd64 RELENG_8 stable
>Organization:
Collaborative Fusion, Inc.
>Environment:
FreeBSD cyclonus 8.0-STABLE FreeBSD 8.0-STABLE #0: Thu Mar 25 19:07:58 EDT 2010     root at cyclonus:/usr/obj/export/src-RELENG_8/src/sys/GENERIC  amd64

>Description:
Both:

  sys/nfsclient/nfs_vfsops.c
  fs/nfsclient/nfs_clvfsops.c 

  Have:

static const char *nfs_opts[] = { "from", "nfs_args",
    "noatime", "noexec", "suiddir", "nosuid", "nosymfollow", "union",
    "noclusterr", "noclusterw", "multilabel", "acls", "force", "update",
    "async", "dumbtimer", "noconn", "nolockd", "intr", "rdirplus", "resvport",
    "readdirsize", "soft", "hard", "mntudp", "tcp", "udp", "wsize", "rsize",
    "retrans", "acregmin", "acregmax", "acdirmin", "acdirmax", 
    "deadthresh", "hostname", "timeout", "addr", "fh", "nfsv3", "sec",
    "maxgroups", "principal", "negnametimeo",
    NULL };

'export' is not an option, as any NFS client file system wouldn't be assume to have one.  

But somehow the VFS->NFS Client/Diskless code is setting  and its failing in the array passed to:

   kern/vfs_mount.c::vfs_filteropt()
>How-To-Repeat:
PXE Boot a system with NFS (not TFTP) root file system:

Use the following config:

DHCP:
option root-path "192.168.224.67:/export/tftpboot/root-db";

loader.rc:

set vfs.root.mountfrom="nfs"
set vfs.root.mountfrom.options="rw"
set boot.nfsroot.path="/export/tftpboot/root-web"
set boot.nfsroot.server="192.168.224.67"

loader.conf:

mfsroot_load="NO"
nfsclient_load="YES"
init_path=/stand/sysinstall
autoboot_delay=2

The kernel DMESG/KLOG output prints:

 "mount option <export> is unknown"

My original message was:

  http://unix.derkeiler.com/Mailing-Lists/FreeBSD/questions/2010-04/msg01137.html

I can provide screenshot.
>Fix:
To be determined.

>Release-Note:
>Audit-Trail:
>Unformatted: