Re: Installing Fedora Core with root on Reiserfs

Re: Installing Fedora Core with root on Reiserfs

[Russell Coker]

On Monday 18 July 2005 06:01, Edward Shishkin <edward@namesys.com> wrote:
> FC4-test3 (and perhaps FC4) installs its own version of grub which seems
> to interact incorrectly with reiserfs. The problem is that reiserfs.ko
> module located on reiserfs partition can not be loaded.

Firstly there is no situation in which reiserfs.ko will be loaded from a 
reiserfs partition.

If the root file system is reiserfs then reiserfs.ko will (or at least should) 
be included in the initrd.  The GRUB support for ReiserFS is based on the 
file /boot/grub/reiserfs_stage1_5 which is only needed for /boot on ReiserFS.

Some people believe that /boot should be a separate file system to the root 
file system regardless of all other issues.  All systems which use LVM for 
the root file system on Fedora (the default partitioning involves LVM) will 
have a separate /boot file system because GRUB apparently doesn't support LVM 
(yet).

So having a /boot with Ext2/3 is an easy solution to any ReiserFS booting 
issues, and a solution that will be forced on the users if they use LVM.  
When using a small /boot file system ReiserFS is not a good choice.  A quick 
test showed that Ext3 gave 18M more usable disk space from a 100M file system 
than ReiserFS, this will essentially force all LVM users to use Ext3 
for /boot.

> 1. (Requires some partition formatted by ext2).
>    At the end of installation process (after invitation to reboot) boot
> from some rescue CD, mount reiserfs root partition (say to /mnt) and move
> all the compressed images (vmlinuz-xxx and initrd-xxx located at /mnt/boot)
> to your ext2 partition. Then edit the file /mnt/boot/grub/grub.conf
> pointing a new location for the images. Reboot and finish the
> installation
>    process.

This can be done automatically through the Anaconda GUI or through kickstart.  
Just specify that /boot is to be a separate partition of type Ext3.

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Re: Installing Fedora Core with root on Reiserfs

[Edward Shishkin]

Russell Coker wrote:

>On Monday 18 July 2005 06:01, Edward Shishkin <edward@namesys.com> wrote:
>  
>
>>FC4-test3 (and perhaps FC4) installs its own version of grub which seems
>>to interact incorrectly with reiserfs. The problem is that reiserfs.ko
>>module located on reiserfs partition can not be loaded.
>>    
>>
>
>Firstly there is no situation in which reiserfs.ko will be loaded from a 
>reiserfs partition.
>  
>

Hmmm... actually this is a default situation when installing with root 
on reiserfs..

>If the root file system is reiserfs then reiserfs.ko will (or at least should) 
>be included in the initrd. 
>

Right, but initrd is in /boot which is not something separate: it is on the
same reiserfs root partition..

> The GRUB support for ReiserFS is based on the 
>file /boot/grub/reiserfs_stage1_5 which is only needed for /boot on ReiserFS.
>
>Some people believe that /boot should be a separate file system to the root 
>file system regardless of all other issues.  All systems which use LVM for 
>the root file system on Fedora (the default partitioning involves LVM) will 
>have a separate /boot file system because GRUB apparently doesn't support LVM 
>(yet).
>
>So having a /boot with Ext2/3 is an easy solution to any ReiserFS booting 
>issues, and a solution that will be forced on the users if they use LVM.  
>When using a small /boot file system ReiserFS is not a good choice.  A quick 
>test showed that Ext3 gave 18M more usable disk space from a 100M file system 
>than ReiserFS, this will essentially force all LVM users to use Ext3 
>for /boot.
>
>  
>
>>1. (Requires some partition formatted by ext2).
>>   At the end of installation process (after invitation to reboot) boot
>>from some rescue CD, mount reiserfs root partition (say to /mnt) and move
>>all the compressed images (vmlinuz-xxx and initrd-xxx located at /mnt/boot)
>>to your ext2 partition. Then edit the file /mnt/boot/grub/grub.conf
>>pointing a new location for the images. Reboot and finish the
>>installation
>>   process.
>>    
>>
>
>This can be done automatically through the Anaconda GUI or through kickstart.  
>Just specify that /boot is to be a separate partition of type Ext3.
>
>  
>

Re: Installing Fedora Core with root on Reiserfs

[Jeff Mahoney]

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Hash: SHA1

Edward Shishkin wrote:
> Russell Coker wrote:
> 
>> On Monday 18 July 2005 06:01, Edward Shishkin <edward@namesys.com> wrote:
>>  
>>
>>> FC4-test3 (and perhaps FC4) installs its own version of grub which seems
>>> to interact incorrectly with reiserfs. The problem is that reiserfs.ko
>>> module located on reiserfs partition can not be loaded.
>>>   
>>
>> Firstly there is no situation in which reiserfs.ko will be loaded from
>> a reiserfs partition.
>>  
>>
> 
> Hmmm... actually this is a default situation when installing with root
> on reiserfs..
> 
>> If the root file system is reiserfs then reiserfs.ko will (or at least
>> should) be included in the initrd.
> 
> Right, but initrd is in /boot which is not something separate: it is on the
> same reiserfs root partition..

The situation you're describing is one that is well tested by now.

If the root filesystem is reiserfs, and /boot is a part of it,
reiserfs.ko MUST be in the initrd. Otherwise, there is a chicken/egg
problem and the system will not boot.

The initrd being on a reiserfs filesystem is fine since grub doesn't use
any kernel services when it's executing. Grub loads the kernel and the
initrd itself before transferring control to the kernel and uses no
kernel services to do so. Grub has its own filesystem reading code which
gets pointed to during installation.

So, if there is truly a problem with this, I'd look at Fedora's mkinitrd.

- -Jeff


- --
Jeff Mahoney
SuSE Labs
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Re: Installing Fedora Core with root on Reiserfs

[Hans Reiser]

Edward, please drive this to a solution.  Thanks Jeff.

Hans

Jeff Mahoney wrote:

> Edward Shishkin wrote:
>
> >Russell Coker wrote:
>
> >>On Monday 18 July 2005 06:01, Edward Shishkin <edward@namesys.com>
> wrote:
> >>
> >>
> >>>FC4-test3 (and perhaps FC4) installs its own version of grub which
> seems
> >>>to interact incorrectly with reiserfs. The problem is that reiserfs.ko
> >>>module located on reiserfs partition can not be loaded.
> >>>  
> >>
> >>Firstly there is no situation in which reiserfs.ko will be loaded from
> >>a reiserfs partition.
> >>
> >>
> >Hmmm... actually this is a default situation when installing with root
> >on reiserfs..
>
> >>If the root file system is reiserfs then reiserfs.ko will (or at least
> >>should) be included in the initrd.
>
> >Right, but initrd is in /boot which is not something separate: it is
> on the
> >same reiserfs root partition..
>
>
> The situation you're describing is one that is well tested by now.
>
> If the root filesystem is reiserfs, and /boot is a part of it,
> reiserfs.ko MUST be in the initrd. Otherwise, there is a chicken/egg
> problem and the system will not boot.
>
> The initrd being on a reiserfs filesystem is fine since grub doesn't use
> any kernel services when it's executing. Grub loads the kernel and the
> initrd itself before transferring control to the kernel and uses no
> kernel services to do so. Grub has its own filesystem reading code which
> gets pointed to during installation.
>
> So, if there is truly a problem with this, I'd look at Fedora's mkinitrd.
>
> -Jeff
>
>
> --
> Jeff Mahoney
> SuSE Labs

Re: Installing Fedora Core with root on Reiserfs

[Russell Coker]

On Tuesday 19 July 2005 01:59, Jeff Mahoney <jeffm@suse.com> wrote:
> >> If the root file system is reiserfs then reiserfs.ko will (or at least
> >> should) be included in the initrd.
> >
> > Right, but initrd is in /boot which is not something separate: it is on
> > the same reiserfs root partition..
>
> The situation you're describing is one that is well tested by now.
>
> If the root filesystem is reiserfs, and /boot is a part of it,
> reiserfs.ko MUST be in the initrd. Otherwise, there is a chicken/egg
> problem and the system will not boot.

This works in all my tests.  The reiserfs.ko module is apparently in the 
initrd.

Also if the original bug concerned a lack of reiserfs.ko in the initrd then 
re-running GRUB would not fix things.

I can't reproduce the bug, it just works for me.

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Re: Installing Fedora Core with root on Reiserfs

[Edward Shishkin]

Russell Coker wrote:

>On Tuesday 19 July 2005 01:59, Jeff Mahoney <jeffm@suse.com> wrote:
>  
>
>>>>If the root file system is reiserfs then reiserfs.ko will (or at least
>>>>should) be included in the initrd.
>>>>        
>>>>
>>>Right, but initrd is in /boot which is not something separate: it is on
>>>the same reiserfs root partition..
>>>      
>>>
>>The situation you're describing is one that is well tested by now.
>>
>>If the root filesystem is reiserfs, and /boot is a part of it,
>>reiserfs.ko MUST be in the initrd. Otherwise, there is a chicken/egg
>>problem and the system will not boot.
>>    
>>
>
>This works in all my tests.  The reiserfs.ko module is apparently in the 
>initrd.
>
>Also if the original bug concerned a lack of reiserfs.ko in the initrd then 
>re-running GRUB would not fix things.
>
>I can't reproduce the bug, it just works for me.
>
>  
>

Sorry for the confusion.
My phrase "reiserfs.ko located on reiserfs" sounds bad, and I should
clarify that the reiserfs.ko is contained in the initrd with other
binaries/scripts, and this initrd looks fine from the standpoint of
kernel/reiserfs, but not from the standpoint of grub/reiserfs-emulation.
The logs obtained from serial console don't include anything about
loading initrd, and there is the following detail: a dump created by
debugreiserfs -d shows that the initrd (i_size: 1128235) is represented
by an indirect item (276 4K-blocks), while grub found that this is not
sector-aligned:

debugreiserfs:
--------------
|  0|54 17448 0x1 IND (1), len 1104, location 2992 entry count 0, fsck 
need 0, format new|
276 pointers
[ 1347049(276)]
  ^^^^^^^

grub:
--------------
grub> blocklist /boot/initrd-2.6.11-1.1286_FC4smp.img
(hd0,4)10776392[10-512],10776393+15,10776408[0-10],10776408[10-512],10776409+15,...
       ^^^^^^^^^^^^^^^^
...,10778584[10-512],10778585+11
(the actual dump is large, so I have cut the middle)

This blocklist doesn't contain last zeroed sectors 10778596-10778599
occupied by the initrd, but I am not sure if it is essential. The
"mysterious offset 10" looks more suspiciously.
I'll look at grub internals which are responsible for accessing reiserfs..

Thanks to everyone,
Edward.

Re: Installing Fedora Core with root on Reiserfs

[Russell Coker]

On Thursday 21 July 2005 10:04, Edward Shishkin <edward@namesys.com> wrote:
> My phrase "reiserfs.ko located on reiserfs" sounds bad, and I should
> clarify that the reiserfs.ko is contained in the initrd with other
> binaries/scripts, and this initrd looks fine from the standpoint of
> kernel/reiserfs, but not from the standpoint of grub/reiserfs-emulation.
> The logs obtained from serial console don't include anything about
> loading initrd, and there is the following detail: a dump created by
> debugreiserfs -d shows that the initrd (i_size: 1128235) is represented
> by an indirect item (276 4K-blocks), while grub found that this is not
> sector-aligned:

Might this be related to the size of the ReiserFS file system?

I tested installs with the default partitioning (100M /boot) which worked OK.  
When you had the problem were you using a larger ReiserFS file system?

-- 
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http://www.coker.com.au/bonnie++/  Bonnie++ hard drive benchmark
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Re: Installing Fedora Core with root on Reiserfs

[Leo Comerford]

On 7/18/05, Russell Coker <russell@coker.com.au> wrote:
> On Monday 18 July 2005 06:01, Edward Shishkin <edward@namesys.com> wrote:
> > FC4-test3 (and perhaps FC4) installs its own version of grub which seems
> > to interact incorrectly with reiserfs. The problem is that reiserfs.ko
> > module located on reiserfs partition can not be loaded.

I can confirm that there is a reiserfs/GRUB problem in the final FC4
release too. (I assume it's the same problem, but I haven't
investigated it.) FWIW - evidently not much - the relevant Fedora
Bugzilla bug would appear to be 161306.