Regression: overwrite option not working

[Ronny Standtke]

Hi all,

I am still trying out the persistent image feature and run into a regression.

I put Knoppix on a USB stick together with a persistent image and was trying
it out on several machines. This was working exceptionally bad, because the
hardware configuration from the very first Knoppix boot was saved in the
persistent image and was automatically used on all machines afterwards. It
was not really obvious to me that this behaviour was the default. In my
opinion this is really a bad choice to not overwrite the settings by default,
because it makes the system more or less non-portable.

Then I remembered that I have read somewhere about this "overwrite" option.
Unfortunately, I could not find any description in the documentation. Anyway,
I tried this option and ... it just did't work.
Everytime I select this option Knoppix just hangs with the following error
message:
------------
rsync: recv_generator: failed to stat "/UNIONFS/etc/ssh.wh..wh..opq":
Operation not permitted (1)
------------
Is there any workaround for this problem? I really need this to work.

I tried the same procedure with Knoppix-5.1.1. There is also an error message
from rsync but at least it does not get stuck in the boot sequence...

Regards.

Ronny

PS: Is it spelled "KNOPPIX" or "Knoppix"? Even on http://www.knoppix.org/ I
see both variants on the same page...


--
To UNSUBSCRIBE, email to debian-knoppix-request@...
with a subject of "unsubscribe". Trouble? Contact listmaster@...

[Ronny Standtke]

Hi there,

> Everytime I select this option Knoppix just hangs with the following error
> message:
> ------------
> rsync: recv_generator: failed to stat "/UNIONFS/etc/ssh.wh..wh..opq":
> Operation not permitted (1)
> ------------
> Is there any workaround for this problem? I really need this to work.

Those .wh..* files seem to be special aufs files. I fixed the bug by adding
another --exclude to the rsync in knoppix-image (see attached patch).
I am no aufs expert and I do not understand all consequences of excluding
these files. I leave the evaluation to the experts. Klaus? :-)

Regards

Ronny

[knoppix-image.diff]

---

--- knoppix-image.original 2008-05-02 23:32:07.000000000 +0200
+++ knoppix-image.patched 2008-05-02 23:33:28.000000000 +0200
@@ -312,7 +312,7 @@
 esac
 
 case "$SELECTION" in *overwrite*)
- [ -z "$OLDHOMEDIR" ] && rsync --update --exclude /ramdisk/etc/mtab -Ha /ramdisk/etc/ /UNIONFS/etc
+ [ -z "$OLDHOMEDIR" ] && rsync --update --exclude .wh.* --exclude /ramdisk/etc/mtab -Ha /ramdisk/etc/ /UNIONFS/etc
 ;;
 esac
 

---

[Klaus Knopper-2]

Hello Ronny,

On Fri, May 02, 2008 at 11:48:30PM +0200, Ronny Standtke wrote:

> Hi there,
>
> > Everytime I select this option Knoppix just hangs with the following error
> > message:
> > ------------
> > rsync: recv_generator: failed to stat "/UNIONFS/etc/ssh.wh..wh..opq":
> > Operation not permitted (1)
> > ------------
> > Is there any workaround for this problem? I really need this to work.
>
> Those .wh..* files seem to be special aufs files.

Right, they notify aufs of files on the read-only branch that have been
(virtually) removed from the filesystem (since you understandably cannot
remove files from the read-only branch), or renamed. I think I made too
many relaxed assumptions in copying only files from the
read/write-branch with all the meta information, but then, parsing the
entire unionfs tree for changes would take a few minutes at least, while
nl copying from the changed branch will speed up the process.

> I fixed the bug by adding
> another --exclude to the rsync in knoppix-image (see attached patch).
> I am no aufs expert and I do not understand all consequences of excluding
> these files. I leave the evaluation to the experts. Klaus? :-)

I think it should be OK, the only thing left out would probably be
removed files that are not going to be removed on the added knoppix.img
branch. I'm going to add your patch in the next release as well, thanks!
:-)

-Klaus


--
To UNSUBSCRIBE, email to debian-knoppix-request@...
with a subject of "unsubscribe". Trouble? Contact listmaster@...

[Klaus Knopper-2]

Just a small add-on:

--exclude .wh.* should be --exclude '.wh.*', for the admittedly unlikely
case that there are files present that match this pattern in the current
directory.

To answer your previous question: The default options set in the
knoppix-image dialog, where "overwrite" is unchecked, are set for (my
humble assumption) the most common case, for using the same CD/DVD
frequently on the same computer without a full install, so that the OS
stays on DVD, and the personal data and settings stay on a local
harddisk or on a memorystick. This is a common case also for teachers
teaching in the same classroom. For a different classroom or class, with
different programs, they would presumably also use an entirely different
image.

That's the reason why I thought the "overwrite" option should not be
active by default, also in order not to overwrite a possibly manually
changed xorg configuration by accident.

What's also missing in knoppix-image is, restarting services like
network mounts and static IP addresses. This can be done by the usual
init scripts, but does not always work well, since /etc/rcS.d is only
parsed once before knoppix-autoconfig, and not after the new unified
filesystem is established.

The only reason why this has not been changed yet is, because nobody
(including me) has complained yet about the missing feature. ;-)

Regards
-Klaus Knopper


--
To UNSUBSCRIBE, email to debian-knoppix-request@...
with a subject of "unsubscribe". Trouble? Contact listmaster@...

[Ronny Standtke]

Hi Klaus,

> To answer your previous question: The default options set in the
> knoppix-image dialog, where "overwrite" is unchecked, are set for (my
> humble assumption) the most common case, for using the same CD/DVD
> frequently on the same computer without a full install, so that the OS
> stays on DVD, and the personal data and settings stay on a local
> harddisk or on a memorystick.

OK, now I understand. I put Knoppix on a USB flash drive, add a persistent
Knoppix image (so that all personal settings and data is preserved and
additional programs can be installed) and hand it out to teachers and
students who run around and stick the USB flash drive into every computer
they can get their hands on. My use case is probably less common.

One little idea came to my mind... Isn't running mkxorgconfig unnecessary when
the overwrite option is not used? You could boot up faster if you rearranged
the order of the bootup scripts a little. What do you think? As always, you
are the expert and I am just guessing. ;-)

Regards

Ronny


--
To UNSUBSCRIBE, email to debian-knoppix-request@...
with a subject of "unsubscribe". Trouble? Contact listmaster@...

[Ronny Standtke]

Hi all,

Today I was using Knoppix on quite many computers, one after another. On one
computer, where it normally works just fine, it was not starting up
correctly. I got all different kinds of error messages and X11 did only start
up after some failed attempts. So, I switched again to bug-hunting mode for
the rest of the day...

I booted with "knoppix 2" and took a look at the config files. To my surprise
the xorg.conf had the wrong driver. I was very surprised, because I use the
overwrite option in knoppix-image per default. The correct xorg.conf was
sitting in the /ramdisk directory but did not end up in /UNIONFS. Very
strange. Why was the rsync command in knoppix-image not working? I noticed
the option "--update", read the man page, understood what it does and checked
the time stamps of the files. Bingo! The xorg.conf in /UNIONFS was newer than
the one in /ramdisk. But how can this happen? I checked the last two
computers I used and everything became clear: The previous machine had
Windows on its hard disk and was using localtime for the hardware clock, the
last machine was running Linux and was using UTC. The xorg.conf created on
the previous machine therefore was "newer" then the one just created by
mkxorgconfig and was not updated.

To make a long story short: Please remove the option "--update" from the rsync
command in knoppix-image. It breaks Knoppix under certain circumstances.

Greetings

Ronny


--
To UNSUBSCRIBE, email to debian-knoppix-request@...
with a subject of "unsubscribe". Trouble? Contact listmaster@...