nfsroot.txt in 2.4.36.7 and 2.6.27.1, Configure.help in 2.4.36.7: missing precondition CONFIG_IP_PNP

nfsroot.txt in 2.4.36.7 and 2.6.27.1, Configure.help in 2.4.36.7: missing precondition CONFIG_IP_PNP

[Hartmut Niemann]

[-- Attachment #1: Type: text/plain, Size: 1438 bytes --]

Hello everybody!

In kernel versions 2.4.36.7 and 2.6.27.1 (I checked only these) the file 
nfsroot.txt fail to mention, that
Kernel level autoconfiguration CONFIG_IP_PNP *must* be selected
(in 2.6.27.1 the wording is much better mentioning that nfs may not be
compiled as a module than in 2.4.36.7) 
in order to be able to even *see* the option
"Root file system on NFS" (CONFIG_ROOT_NFS)
-- except for xconfig in 2.4.36, which allowed me to see that there is 
this option (greyed), and to see it's help text. (This, by the way,
was a big help -- I could see that the option is still present in current
kernels)

I reordered the section 1 of nfsroot.txt (of 2.6.27.1), diff is attached.
(And I fixed some chapter numbering in section 3).
Is this document otherwise correct for 2.4 and can be updated there too?
The version in 2.4.36.7 is 

The help text of CONFIG_ROOT_NFS in 2.4.36.7 is quite funny:
  "It is
  likely that in this case, you also want to say Y to "Kernel level IP
  autoconfiguration" so that your box can discover its network address
  at boot time."
Does that make clear that you can not even see this option 
during make *config unless you set "Kernel level IP autoconfiguration"?
The help text of CONFIG_NFS_FS does contain the information,
but I found it there a little late. The texts in 2.6 are better.

A diff for 2.4.36.7 Configure.help is attached as well.

Is this correct?

With best regards
Hartmut Niemann

[-- Attachment #2: nfsroot.txt.diff --]
[-- Type: text/x-diff, Size: 2509 bytes --]

--- nfsroot.txt.orig	2008-10-25 23:18:33.000000000 +0200
+++ nfsroot.txt	2008-10-25 23:24:48.000000000 +0200
@@ -22,15 +22,13 @@
 1.) Enabling nfsroot capabilities
     -----------------------------
 
-In order to use nfsroot, NFS client support needs to be selected as
-built-in during configuration. Once this has been selected, the nfsroot
-option will become available, which should also be selected.
-
-In the networking options, kernel level autoconfiguration can be selected,
-along with the types of autoconfiguration to support. Selecting all of
-DHCP, BOOTP and RARP is safe.
-
-
+In order to use nfsroot, in the networking options,  IP kernel level
+autoconfiguration must be selected, along with the types of autoconfiguration
+to support. Selecting all of DHCP, BOOTP and RARP is safe.
+
+Then NFS client support needs to be selected as built-in during configuration.
+Once this has been selected, the nfsroot option will become available,
+which must also be selected.
 
 
 2.) Kernel command line
@@ -207,7 +205,7 @@
      	For more information on isolinux, including how to create bootdisks
      	for prebuilt kernels, see http://syslinux.zytor.com/
 
-3.2) Using LILO
+3.3) Using LILO
 	When using LILO all the necessary command line parameters may be
 	specified using the 'append=' directive in the LILO configuration
 	file.
@@ -219,11 +217,11 @@
 
 	For information on configuring LILO, please refer to its documentation.
 
-3.3) Using GRUB
+3.4) Using GRUB
 	When using GRUB, kernel parameter are simply appended after the kernel
 	specification: kernel <kernel> <parameters>
 
-3.4) Using loadlin
+3.5) Using loadlin
 	loadlin may be used to boot Linux from a DOS command prompt without
 	requiring a local hard disk to mount as root. This has not been
 	thoroughly tested by the authors of this document, but in general
@@ -232,7 +230,7 @@
 
 	Please refer to the loadlin documentation for further information.
 
-3.5) Using a boot ROM
+3.6) Using a boot ROM
 	This is probably the most elegant way of booting a diskless client.
 	With a boot ROM the kernel is loaded using the TFTP protocol. The
 	authors of this document are not aware of any no commercial boot
@@ -241,7 +239,7 @@
 	etherboot, both of which are available on sunsite.unc.edu, and both
 	of which contain everything you need to boot a diskless Linux client.
 
-3.6) Using pxelinux
+3.7) Using pxelinux
 	Pxelinux may be used to boot linux using the PXE boot loader
 	which is present on many modern network cards.
 

[-- Attachment #3: Configure.help.diff --]
[-- Type: text/x-diff, Size: 900 bytes --]

--- Configure.help.orig	2008-10-25 23:34:25.000000000 +0200
+++ Configure.help	2008-10-25 23:43:37.000000000 +0200
@@ -17262,10 +17262,11 @@
   If you want your Linux box to mount its whole root file system (the
   one containing the directory /) from some other computer over the
   net via NFS (presumably because your box doesn't have a hard disk),
-  say Y. Read <file:Documentation/nfsroot.txt> for details. It is
-  likely that in this case, you also want to say Y to "Kernel level IP
-  autoconfiguration" so that your box can discover its network address
-  at boot time.
+  say Y. Read <file:Documentation/nfsroot.txt> for details.
+  In this case, you also need to say Y to "Kernel level IP
+  autoconfiguration" in the networking options so that your box can
+  discover its network address at boot time, and . Otherwise, you won't be
+  able to say Y here.
 
   Most people say N here.
 

Re: nfsroot.txt in 2.4.36.7 and 2.6.27.1, Configure.help in 2.4.36.7: missing precondition CONFIG_IP_PNP

[Willy Tarreau]

Hi,

On Sat, Oct 25, 2008 at 11:47:01PM +0200, Hartmut Niemann wrote:
> Hello everybody!
> 
> In kernel versions 2.4.36.7 and 2.6.27.1 (I checked only these) the file 
> nfsroot.txt fail to mention, that
> Kernel level autoconfiguration CONFIG_IP_PNP *must* be selected
> (in 2.6.27.1 the wording is much better mentioning that nfs may not be
> compiled as a module than in 2.4.36.7) 
> in order to be able to even *see* the option
> "Root file system on NFS" (CONFIG_ROOT_NFS)
> -- except for xconfig in 2.4.36, which allowed me to see that there is 
> this option (greyed), and to see it's help text. (This, by the way,
> was a big help -- I could see that the option is still present in current
> kernels)

Kbuild in 2.6 is much more evolved than in 2.4 as it knows about
dependencies, and tells the user what needs to be enabled for each
option. It's true that xconfig is sometimes helpful on 2.4 for this
reason, but I tend to grep for the option rather than starting xconfig.

> I reordered the section 1 of nfsroot.txt (of 2.6.27.1), diff is attached.
> (And I fixed some chapter numbering in section 3).
> Is this document otherwise correct for 2.4 and can be updated there too?
> The version in 2.4.36.7 is 
> 
> The help text of CONFIG_ROOT_NFS in 2.4.36.7 is quite funny:
>   "It is
>   likely that in this case, you also want to say Y to "Kernel level IP
>   autoconfiguration" so that your box can discover its network address
>   at boot time."
> Does that make clear that you can not even see this option 
> during make *config unless you set "Kernel level IP autoconfiguration"?
> The help text of CONFIG_NFS_FS does contain the information,
> but I found it there a little late. The texts in 2.6 are better.
> 
> A diff for 2.4.36.7 Configure.help is attached as well.
> 
> Is this correct?

Your explanation seems correct, but it only explains better the option
which you couldn't find. So you still have to enable it first in order
to find how to enable it :-/  I've just checked the help for CONFIG_NFS_FS,
and it is quite clear about the fact that you need to enable IP autoconfig
to enable NFS ROOT. Maybe it is this section which should be enhanced to
tell where to enable those options ?

Willy

Re: nfsroot.txt in 2.4.36.7 and 2.6.27.1, Configure.help in 2.4.36.7: missing precondition CONFIG_IP_PNP

[Hartmut Niemann]

Am Sonntag, 26. Oktober 2008 04:27 schrieb Willy Tarreau:
> > In kernel versions 2.4.36.7 and 2.6.27.1 (I checked only these) the file
> > nfsroot.txt fail to mention, that
> > Kernel level autoconfiguration CONFIG_IP_PNP *must* be selected
> > (in 2.6.27.1 the wording is much better mentioning that nfs may not be
> > compiled as a module than in 2.4.36.7)
> > in order to be able to even *see* the option
> > "Root file system on NFS" (CONFIG_ROOT_NFS)
> > -- except for xconfig in 2.4.36, which allowed me to see that there is
> > this option (greyed), and to see it's help text. (This, by the way,
> > was a big help -- I could see that the option is still present in current
> > kernels)
>
> Kbuild in 2.6 is much more evolved than in 2.4 as it knows about
> dependencies, and tells the user what needs to be enabled for each
> option. It's true that xconfig is sometimes helpful on 2.4 for this
> reason, but I tend to grep for the option rather than starting xconfig.
I grepped in Configure.help too. That was when I noticed that the 
CONFIG_ROOT_NFS help text
didn't help. I found the explanation in CONFIG_NFS_FS when I 
started to edit Configure.help...

Maybe we should change the CONFIG_ROOT_NFS help section to
"please read the CONFIG_NFS_FS help".

By the way: 2.6 kbuild won't tell you anything about how to activate 
CONFIG_ROOT_NFS unless the dependencies are met i.e. 
CONFIG_IP_PNP is set, so while it 
lists the dependencies, it does that only for those options that it will
allow to be set. Otherwise you won't even see that there is an 
option "CONFIG_ROOT_NFS" and won't be able to select it's help text to be 
displayed. That makes the dependencies in the helptext less valuable.
I checked that for menuconfig and xconfig.
>
> > I reordered the section 1 of nfsroot.txt (of 2.6.27.1), diff is attached.
> > (And I fixed some chapter numbering in section 3).
> > Is this document otherwise correct for 2.4 and can be updated there too?
> > The version in 2.4.36.7 is
> >
> > The help text of CONFIG_ROOT_NFS in 2.4.36.7 is quite funny:
> >   "It is
> >   likely that in this case, you also want to say Y to "Kernel level IP
> >   autoconfiguration" so that your box can discover its network address
> >   at boot time."
> > Does that make clear that you can not even see this option
> > during make *config unless you set "Kernel level IP autoconfiguration"?
> > The help text of CONFIG_NFS_FS does contain the information,
> > but I found it there a little late. The texts in 2.6 are better.
> >
> > A diff for 2.4.36.7 Configure.help is attached as well.
> >
> > Is this correct?
>
> Your explanation seems correct, but it only explains better the option
> which you couldn't find. So you still have to enable it first in order
> to find how to enable it :-/  I've just checked the help for CONFIG_NFS_FS,
> and it is quite clear about the fact that you need to enable IP autoconfig
> to enable NFS ROOT. Maybe it is this section which should be enhanced to
> tell where to enable those options ?

No. Once you find out that the CONFIG_NFS_FS help is all you need, you 
succeded.
But if you read nfsroot.txt or anything in the web, it will tell you to enable 
CONFIG_ROOT_NFS, not to read CONFIG_NFS_FS help.
(Maybe my posting will help somebody someday only for the reason that 
it is indexed, found and displayed by $search_engine :-)

Hartmut

Re: nfsroot.txt in 2.4.36.7 and 2.6.27.1, Configure.help in 2.4.36.7: missing precondition CONFIG_IP_PNP

[Simon Horman]

On Sat, Oct 25, 2008 at 11:47:01PM +0200, Hartmut Niemann wrote:
> Hello everybody!
> 
> In kernel versions 2.4.36.7 and 2.6.27.1 (I checked only these) the file 
> nfsroot.txt fail to mention, that
> Kernel level autoconfiguration CONFIG_IP_PNP *must* be selected
> (in 2.6.27.1 the wording is much better mentioning that nfs may not be
> compiled as a module than in 2.4.36.7) 
> in order to be able to even *see* the option
> "Root file system on NFS" (CONFIG_ROOT_NFS)
> -- except for xconfig in 2.4.36, which allowed me to see that there is 
> this option (greyed), and to see it's help text. (This, by the way,
> was a big help -- I could see that the option is still present in current
> kernels)
> 
> I reordered the section 1 of nfsroot.txt (of 2.6.27.1), diff is attached.
> (And I fixed some chapter numbering in section 3).
> Is this document otherwise correct for 2.4 and can be updated there too?
> The version in 2.4.36.7 is 
> 
> The help text of CONFIG_ROOT_NFS in 2.4.36.7 is quite funny:
>   "It is
>   likely that in this case, you also want to say Y to "Kernel level IP
>   autoconfiguration" so that your box can discover its network address
>   at boot time."
> Does that make clear that you can not even see this option 
> during make *config unless you set "Kernel level IP autoconfiguration"?
> The help text of CONFIG_NFS_FS does contain the information,
> but I found it there a little late. The texts in 2.6 are better.
> 
> A diff for 2.4.36.7 Configure.help is attached as well.
> 
> Is this correct?

Hi Hartmut,

I think that your changes to nfsroot.txt are good and should
be considered for inclusion in a future release (probably 2.6.29).

In order to aid this could you please do the following and resend the patch

1) Trim down the description above to only describe the nfsroot.txt
   changes.

2) Add a full path to the patch. Basically
 
	--- nfsroot.txt.orig	2008-10-25 23:18:33.000000000 +0200
	+++ nfsroot.txt	2008-10-25 23:24:48.000000000 +0200

  should be

	--- a/Documentation/filesystems/nfsroot.txt	2008-10-25 23:18:33.000000000 +0200
	+++ b/Documentation/filesystems/nfsroot.txt	2008-10-25 23:24:48.000000000 +0200

  where "a" and "b" can be anything you like, though "a" and "b" are just
  fine.

3) sign off the patch, as per Documentation/SubmittingPatches


I'm not so sure of the Configure.help change and I tend to agree with Willy
Tarreau's comments. As you point out this change is for 2.4.36.7 (and not
2.6.29). So if you want to persue this change, lets discuss that separately
to the inclusion of the nfsroot.txt change in 2.6.29.

> --- nfsroot.txt.orig	2008-10-25 23:18:33.000000000 +0200
> +++ nfsroot.txt	2008-10-25 23:24:48.000000000 +0200
> @@ -22,15 +22,13 @@
>  1.) Enabling nfsroot capabilities
>      -----------------------------
>  
> -In order to use nfsroot, NFS client support needs to be selected as
> -built-in during configuration. Once this has been selected, the nfsroot
> -option will become available, which should also be selected.
> -
> -In the networking options, kernel level autoconfiguration can be selected,
> -along with the types of autoconfiguration to support. Selecting all of
> -DHCP, BOOTP and RARP is safe.
> -
> -
> +In order to use nfsroot, in the networking options,  IP kernel level
> +autoconfiguration must be selected, along with the types of autoconfiguration
> +to support. Selecting all of DHCP, BOOTP and RARP is safe.
> +
> +Then NFS client support needs to be selected as built-in during configuration.
> +Once this has been selected, the nfsroot option will become available,
> +which must also be selected.
>  
>  
>  2.) Kernel command line
> @@ -207,7 +205,7 @@
>       	For more information on isolinux, including how to create bootdisks
>       	for prebuilt kernels, see http://syslinux.zytor.com/
>  
> -3.2) Using LILO
> +3.3) Using LILO
>  	When using LILO all the necessary command line parameters may be
>  	specified using the 'append=' directive in the LILO configuration
>  	file.
> @@ -219,11 +217,11 @@
>  
>  	For information on configuring LILO, please refer to its documentation.
>  
> -3.3) Using GRUB
> +3.4) Using GRUB
>  	When using GRUB, kernel parameter are simply appended after the kernel
>  	specification: kernel <kernel> <parameters>
>  
> -3.4) Using loadlin
> +3.5) Using loadlin
>  	loadlin may be used to boot Linux from a DOS command prompt without
>  	requiring a local hard disk to mount as root. This has not been
>  	thoroughly tested by the authors of this document, but in general
> @@ -232,7 +230,7 @@
>  
>  	Please refer to the loadlin documentation for further information.
>  
> -3.5) Using a boot ROM
> +3.6) Using a boot ROM
>  	This is probably the most elegant way of booting a diskless client.
>  	With a boot ROM the kernel is loaded using the TFTP protocol. The
>  	authors of this document are not aware of any no commercial boot
> @@ -241,7 +239,7 @@
>  	etherboot, both of which are available on sunsite.unc.edu, and both
>  	of which contain everything you need to boot a diskless Linux client.
>  
> -3.6) Using pxelinux
> +3.7) Using pxelinux
>  	Pxelinux may be used to boot linux using the PXE boot loader
>  	which is present on many modern network cards.
>  

> --- Configure.help.orig	2008-10-25 23:34:25.000000000 +0200
> +++ Configure.help	2008-10-25 23:43:37.000000000 +0200
> @@ -17262,10 +17262,11 @@
>    If you want your Linux box to mount its whole root file system (the
>    one containing the directory /) from some other computer over the
>    net via NFS (presumably because your box doesn't have a hard disk),
> -  say Y. Read <file:Documentation/nfsroot.txt> for details. It is
> -  likely that in this case, you also want to say Y to "Kernel level IP
> -  autoconfiguration" so that your box can discover its network address
> -  at boot time.
> +  say Y. Read <file:Documentation/nfsroot.txt> for details.
> +  In this case, you also need to say Y to "Kernel level IP
> +  autoconfiguration" in the networking options so that your box can
> +  discover its network address at boot time, and . Otherwise, you won't be
> +  able to say Y here.
>  
>    Most people say N here.
>  


-- 
Simon Horman
  VA Linux Systems Japan K.K., Sydney, Australia Satellite Office
  H: www.vergenet.net/~horms/             W: www.valinux.co.jp/en

[PATCH] Documentation/filesystems/nfsroot.txt: CONFIG_IP_PNP must be set

[Hartmut Niemann]

The file nfsroot.txt fails to mention, that Kernel level autoconfiguration 
CONFIG_IP_PNP must be selected in order to be able to even see
the option "Root file system on NFS" (CONFIG_ROOT_NFS)

I reordered the section 1 of nfsroot.txt and emphasized the dependency.
(And I fixed some chapter numbering in section 3).

Signed-off-by: Hartmut Niemann <Hartmut.Niemann@gmx.de>
---
--- linux-2.6.27.1/Documentation/filesystems/nfsroot.txt        2008-10-16 
01:02:53.000000000 +0200
+++ linux-2.6.27.1-HN/Documentation/filesystems/nfsroot.txt     2008-10-25 
23:24:48.000000000 +0200
@@ -22,15 +22,13 @@
 1.) Enabling nfsroot capabilities
     -----------------------------

-In order to use nfsroot, NFS client support needs to be selected as
-built-in during configuration. Once this has been selected, the nfsroot
-option will become available, which should also be selected.
-
-In the networking options, kernel level autoconfiguration can be selected,
-along with the types of autoconfiguration to support. Selecting all of
-DHCP, BOOTP and RARP is safe.
-
-
+In order to use nfsroot, in the networking options,  IP kernel level
+autoconfiguration must be selected, along with the types of autoconfiguration
+to support. Selecting all of DHCP, BOOTP and RARP is safe.
+
+Then NFS client support needs to be selected as built-in during
+configuration. Once this has been selected, the nfsroot option will become
+available, which must also be selected.


 2.) Kernel command line
@@ -207,7 +205,7 @@
        For more information on isolinux, including how to create bootdisks
        for prebuilt kernels, see http://syslinux.zytor.com/

-3.2) Using LILO
+3.3) Using LILO
        When using LILO all the necessary command line parameters may be
        specified using the 'append=' directive in the LILO configuration
        file.
@@ -219,11 +217,11 @@

        For information on configuring LILO, please refer to its 
documentation.

-3.3) Using GRUB
+3.4) Using GRUB
        When using GRUB, kernel parameter are simply appended after the kernel
        specification: kernel <kernel> <parameters>

-3.4) Using loadlin
+3.5) Using loadlin
        loadlin may be used to boot Linux from a DOS command prompt without
        requiring a local hard disk to mount as root. This has not been
        thoroughly tested by the authors of this document, but in general
@@ -232,7 +230,7 @@

        Please refer to the loadlin documentation for further information.

-3.5) Using a boot ROM
+3.6) Using a boot ROM
        This is probably the most elegant way of booting a diskless client.
        With a boot ROM the kernel is loaded using the TFTP protocol. The
        authors of this document are not aware of any no commercial boot
@@ -241,7 +239,7 @@
        etherboot, both of which are available on sunsite.unc.edu, and both
        of which contain everything you need to boot a diskless Linux client.

-3.6) Using pxelinux
+3.7) Using pxelinux
        Pxelinux may be used to boot linux using the PXE boot loader
        which is present on many modern network cards.

Re: [PATCH] Documentation/filesystems/nfsroot.txt: CONFIG_IP_PNP must be set

[Matthias Schniedermeyer]

On 27.10.2008 22:41, Hartmut Niemann wrote:
> The file nfsroot.txt fails to mention, that Kernel level autoconfiguration 
> CONFIG_IP_PNP must be selected in order to be able to even see
> the option "Root file system on NFS" (CONFIG_ROOT_NFS)
> 
> I reordered the section 1 of nfsroot.txt and emphasized the dependency.
> (And I fixed some chapter numbering in section 3).

Technically you neither need autoconfiguration nor CONFIG_ROOT_NFS.

With an initrd/initramfs you can do the whole procedure from userspace.

And AFAIR a few years back those options where on the brink of beeing 
deprecated for just that reason.


Just my 2 cents.




Bis denn

-- 
Real Programmers consider "what you see is what you get" to be just as 
bad a concept in Text Editors as it is in women. No, the Real Programmer
wants a "you asked for it, you got it" text editor -- complicated, 
cryptic, powerful, unforgiving, dangerous.

Re: nfsroot.txt in 2.4.36.7 and 2.6.27.1, Configure.help in 2.4.36.7: missing precondition CONFIG_IP_PNP

[Bodo Eggert]

Hartmut Niemann <Hartmut.Niemann@gmx.de> wrote:

> Maybe we should change the CONFIG_ROOT_NFS help section to
> "please read the CONFIG_NFS_FS help".

make config will not allow reading the CONFIG_NFS_FS help while asking for
CONFIG_ROOT_NFS.