[BUG] nfs version 2 broken

[BUG] nfs version 2 broken

[Knut Petersen]

Hi everybody,

The good news is that I finally succeeded to boot over network
using the PXE-bootrom / ip dhcp autoconfig / nfsroot method.
But "ip=dhcp root=/dev/nfs nfsroot=%s" is not the way to go
with recent kernels. This results in a kernel panic caused by
the inability to find root. Things go wrong immediately after
rpc port lookup:

 > NFS: Buggy server - nlink == 0!
 > nfs_fhget failed

Well, adding ",v3" to the nfsroot parameter helps, forcing the
client not to use the default nfs version 2 but nfs version 3.

All machines use kernel 2.6.15-git7.

cu,
 Knut

Re: [BUG] nfs version 2 broken

[Trond Myklebust]

On Wed, 2006-02-01 at 07:07 +0100, Knut Petersen wrote:
> Hi everybody,
> 
> The good news is that I finally succeeded to boot over network
> using the PXE-bootrom / ip dhcp autoconfig / nfsroot method.
> But "ip=dhcp root=/dev/nfs nfsroot=%s" is not the way to go
> with recent kernels. This results in a kernel panic caused by
> the inability to find root. Things go wrong immediately after
> rpc port lookup:
> 
>  > NFS: Buggy server - nlink == 0!
>  > nfs_fhget failed

What kind of server is this that you are using? The above message
basically means that it is handing out inodes with a link count of 0.

Cheers,
  Trond

Re: [BUG] nfs version 2 broken

[Knut Petersen]

Trond Myklebust schrieb:

>What kind of server is this that you are using? The above message
>basically means that it is handing out inodes with a link count of 0.
>
>Cheers,
>  Trond
>  
>

Server:
=====

AOpen i915GMm-HFS with Pentium M, linux kernel 2.6.15-git7
running a system that startet as SuSE 9.2. Nfs-utils are still
the original 1.0.6, grep -i nfs linuxbuild/.config gives

    CONFIG_NFS_FS=y
    CONFIG_NFS_V3=y
    # CONFIG_NFS_V3_ACL is not set
    # CONFIG_NFS_V4 is not set
    # CONFIG_NFS_DIRECTIO is not set
    CONFIG_NFSD=y
    CONFIG_NFSD_V3=y
    # CONFIG_NFSD_V3_ACL is not set
    # CONFIG_NFSD_V4 is not set
    CONFIG_NFSD_TCP=y
    CONFIG_NFS_COMMON=y

Client
====

kernel build from the same source,

    CONFIG_NFS_FS=y
    CONFIG_NFS_V3=y
    # CONFIG_NFS_V3_ACL is not set
    # CONFIG_NFS_V4 is not set
    # CONFIG_NFS_DIRECTIO is not set
    CONFIG_NFSD=y
    CONFIG_NFSD_V3=y
    # CONFIG_NFSD_V3_ACL is not set
    # CONFIG_NFSD_V4 is not set
    CONFIG_NFSD_TCP=y
    CONFIG_ROOT_NFS=y
    CONFIG_NFS_COMMON=y

cu,
 Knut

Re: [BUG] nfs version 2 broken

[Trond Myklebust]

On Wed, 2006-02-01 at 07:34 +0100, Knut Petersen wrote:
> Trond Myklebust schrieb:
> 
> >What kind of server is this that you are using? The above message
> >basically means that it is handing out inodes with a link count of 0.
> >
> >Cheers,
> >  Trond
> >  
> >
> 
> Server:
> =====
> 
> AOpen i915GMm-HFS with Pentium M, linux kernel 2.6.15-git7
> running a system that startet as SuSE 9.2. Nfs-utils are still
> the original 1.0.6, grep -i nfs linuxbuild/.config gives

...and what kind of filesystem are you exporting?

Cheers,
  Trond

Re: [BUG] nfs version 2 broken

[Knut Petersen]

>>AOpen i915GMm-HFS with Pentium M, linux kernel 2.6.15-git7
>>running a system that startet as SuSE 9.2. Nfs-utils are still
>>the original 1.0.6, grep -i nfs linuxbuild/.config gives
>>    
>>
>
>...and what kind of filesystem are you exporting?
>
>  
>

linux:/src/k6bv3p # dmesg | grep sda

[4294667.296000] Kernel command line: root=/dev/sda3 
video=intelfb:vram=8 vga=0x307
[   46.848978] SCSI device sda: 488397168 512-byte hdwr sectors (250059 MB)
[   46.850423] sda: Write Protect is off
[   46.851871] sda: Mode Sense: 00 3a 00 10
[   46.851884] SCSI device sda: drive cache: write back w/ FUA
[   46.853385] SCSI device sda: 488397168 512-byte hdwr sectors (250059 MB)
[   46.854868] sda: Write Protect is off
[   46.856330] sda: Mode Sense: 00 3a 00 10
[   46.856342] SCSI device sda: drive cache: write back w/ FUA
[   46.857821]  sda: sda1 sda2 sda3
[   46.869751] sd 0:0:0:0: Attached scsi disk sda
[   20.839566] ReiserFS: sda3: found reiserfs format "3.6" with standard 
journal
[   22.412053] ReiserFS: sda3: using ordered data mode
[   22.417920] ReiserFS: sda3: journal params: device sda3, size 8192, 
journal first block 18, max trans len 1024, max batch900, max commit age 
30, max trans age 30
[   22.419518] ReiserFS: sda3: checking transaction log (sda3)
[   22.440517] ReiserFS: sda3: Using r5 hash to sort names
[   24.597554] Adding 1052216k swap on /dev/sda1.  Priority:42 extents:1 
across:1052216k

(printk timestamp anomalities caused by cpu speed)

cu,
 Knut


cu,
 Knut

Re: [BUG] nfs version 2 broken

[Knut Petersen]

>>AOpen i915GMm-HFS with Pentium M, linux kernel 2.6.15-git7
>>running a system that startet as SuSE 9.2. Nfs-utils are still
>>the original 1.0.6, grep -i nfs linuxbuild/.config gives
>>    
>>
>
>...and what kind of filesystem are you exporting?
>
>  
>

I think it is _not_ related to reiserfs. Moving my
exported /tftpboot directory to a fresh ext2 partition
gave the same results - failing with nfs 2, succeeding with
nfs 3.

cu,
Knut

Re: [BUG] nfs version 2 broken

[Trond Myklebust]

On Wed, 2006-02-01 at 08:13 +0100, Knut Petersen wrote:
> >>AOpen i915GMm-HFS with Pentium M, linux kernel 2.6.15-git7
> >>running a system that startet as SuSE 9.2. Nfs-utils are still
> >>the original 1.0.6, grep -i nfs linuxbuild/.config gives
> >>    
> >>
> >
> >...and what kind of filesystem are you exporting?
> >
> >  
> >
> 
> I think it is _not_ related to reiserfs. Moving my
> exported /tftpboot directory to a fresh ext2 partition
> gave the same results - failing with nfs 2, succeeding with
> nfs 3.

Does it do the same if you mount the same partition normally (i.e. not
through nfsroot) in some other directory?

Cheers,
  Trond

Re: [BUG] nfs version 2 broken

[Knut Petersen]

Trond Myklebust wrote:

>Does it do the same if you mount the same partition normally (i.e. not
>through nfsroot) in some other directory?
>
>  
>

That also fails. Same error message.

Unlike the nfsroot code at least my version of mount
does not use nfs version 2 as the default. I had to force
a v2 nfs mount attempt with mount -o nfsvers=2 ...

Would it be a good idea to change the default nfs version
nfsroot uses? I think nfsroot and mount defaults should
be identical.

BTW: Google shows some related old threads, e.g. "Madhan" writes on
2 Aug. 2001 06:55  "There has been a change in the NFS Client
behaviour in Linux Kernel  2.4.3 onwards.  There are 2 issues here,
1. as traces show new clients expect link count '1' and NetWare
NFS has  been sending '0' for volumes. ..."

cu,
 Knut