Wubi

broken root.disk

Asked by m

My story of frustration:

1.) I was turned on my machine , but grub command prompt was shown instead of starting.
2.) I reboot to windows XP to find out what's up
3.) I tried to open root.disk ( over 10 GB ) , but

"Typ události: Informace
Zdroj události: Application Popup
Kategorie události: Není k dispozici
ID události: 26
Datum: 27. 4. 2011
Čas: 2:52:11
Uživatel: Není k dispozici
Počítač: DESKTOP
Popis:
Místní nabídka aplikace: MagicISO Virtual CD/DVD Manager: MAGICD~1.EXE - Poškozený soubor : Soubor nebo adresář C:\ubuntu\disks\root.disk je poškozen a je nečitelný. Spusťte pomůcku Chkdsk.

Další informace získáte v Centru pro nápovědu a pomoc na http://go.microsoft.com/fwlink/events.asp.
"
happened ( it is in czech language , because XP was czech ) , saying , that root.disk cannot be opened.

4.) I run scandisk , which says something about restart needed , because cannot access disk
5.) After restart , scandisk does something without any questions for me.
6.) I found , that root.disk is missing ( probably deleted by scandisk )
7.) In event log was following record :

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Revision history for this message
m (launch-spam) said : 		#1

Typ události: Informace
Zdroj události: Winlogon
Kategorie události: Není k dispozici
ID události: 1001
Datum: 27. 4. 2011
Čas: 3:26:10
Uživatel: Není k dispozici
Počítač: DESKTOP
Popis:
Kontrola systému souboru na C:
Systém souboru je typu NTFS.
Jmenovka svazku je System.

Nektery z disku vyzaduje kontrolu konzistence. Kontrolu
disku muzete stornovat, durazne vsak doporucujeme
kontrolu provést.
Systém nyní zkontroluje disk.
Kontrolní hodnota USA 0xd0c6 u bloku 0x3 je chybná.
Ocekávaná hodnota je 0xd0c5.
Podpis vícesektorové hlavicky v souboru 0x26a89 je chybny.
42 41 41 44 30 00 03 00 58 29 21 01 09 00 00 00 BAAD0...X)!.....
0c 00 02 00 38 00 01 00 60 03 00 00 00 04 00 00 ....8...`.......
Odstranování poskozeného segmentu 158345 záznamu souboru.
Polozka root.disk indexu $I30 v souboru 0x26a44 odkazuje na nepouzívany soubor 0x26a89.
Odstranování polozky root.disk indexu $I30 souboru 158276.
Polozka ROOT~1.DIS indexu $I30 v souboru 0x26a44 odkazuje na nepouzívany soubor 0x26a89.
Odstranování polozky ROOT~1.DIS indexu $I30 souboru 158276.
Systém odstranuje mensí nekonzistence nalezené na disku.
Systém maze 223 nepouzitych polozek indexu $SII souboru 0x9.
Systém maze 223 nepouzitych polozek indexu $SDH souboru 0x9.
Systém maze 223 nepouzitych popisovacu zabezpecení.
Program CHKDSK nalezl volné místo oznacené jako pridelené v
bitové mape tabulky MFT.
Program CHKDSK nalezl volné místo oznacené jako pridelené v bitové mape svazku.
Systém Windows opravil systém souboru.

 104856223 kB místa na disku celkem.
  62592652 kB v 154363 souborech uzivatele.
     68744 kB v 10883 rejstrících.
         0 kB v chybnych sektorech.
    230843 kB pouzívá systém.
     54512 kB zabírá soubor s protokolem.
  41963984 kB na disku je volnych.

      4096 bajtu v kazdé alokacní jednotce
  26214055 alokacních jednotek na disku celkem.
  10490996 volnych alokacních jednotek

Vnitrní informace:
00 9e 02 00 89 85 02 00 10 44 04 00 00 00 00 00 .........D......
f2 01 00 00 02 00 00 00 11 04 00 00 00 00 00 00 ................
88 07 b4 0c 00 00 00 00 5a da e9 68 00 00 00 00 ........Z..h....
86 57 ef 0f 00 00 00 00 00 00 00 00 00 00 00 00 .W..............
00 00 00 00 00 00 00 00 22 84 90 8c 00 00 00 00 ........".......
f0 9e df 7c 00 00 00 00 00 3a 07 00 fb 5a 02 00 ...|.....:...Z..
00 00 00 00 00 30 5a ec 0e 00 00 00 83 2a 00 00 .....0Z......*..

Systém Windows dokoncil kontrolu disku.
Pockejte prosím, probíhá restartování systému.
Kontrola systému souboru na C:
Systém souboru je typu NTFS.
Jmenovka svazku je System.

Byla naplánována kontrola disku.
Systém nyní zkontroluje disk.
Systém Windows zkontroloval systém souboru a nezjistil zádné potíze.

 104856223 kB místa na disku celkem.
  62592660 kB v 154364 souborech uzivatele.
     68744 kB v 10883 rejstrících.
         0 kB v chybnych sektorech.
    230843 kB pouzívá systém.
     54512 kB zabírá soubor s protokolem.
  41963976 kB na disku je volnych.

      4096 bajtu v kazdé alokacní jednotce
  26214055 alokacních jednotek na disku celkem.
  10490994 volnych alokacních jednotek

Vnitrní informace:
00 9e 02 00 8a 85 02 00 11 44 04 00 00 00 00 00 .........D......
f2 01 00 00 02 00 00 00 32 03 00 00 00 00 00 00 ........2.......
aa cd 99 0c 00 00 00 00 64 93 40 68 00 00 00 00 ........d.@h....
28 87 3c 0f 00 00 00 00 00 00 00 00 00 00 00 00 (.<.............
00 00 00 00 00 00 00 00 da 5c e3 8a 00 00 00 00 .........\......
f0 9e df 7c 00 00 00 00 00 3a 07 00 fc 5a 02 00 ...|.....:...Z..
00 00 00 00 00 50 5a ec 0e 00 00 00 83 2a 00 00 .....PZ......*..

Systém Windows dokoncil kontrolu disku.
Pockejte prosím, probíhá restartování systému.

Další informace získáte v Centru pro nápovědu a pomoc na http://go.microsoft.com/fwlink/events.asp.

Revision history for this message
m (launch-spam) said : 		#2

What am I doing wrong ?
Are my data from Ubuntu unrecoverably lost ?
What to do to prevent this in future ?

Revision history for this message
bcbc (bcbc) said : 		#3

If you do hard shutdowns it's possible to introduce corruption to the root.disk file, and since it is a single large file there is a risk. It's a good idea to back up the file or your data within it to an external source (or to the host partition mounted under /host)
The risk may be higher if there is a lot of fragmentation.

In some cases windows will remove a corrupted file to a hidden folder named C:\FOUND.000 so you should check there for a file matching the size of the root.disk and copy it back if you found it.
But from the output you showed it looks like it might have been deleted.

For future reference, I don't believe magicdisk can read a root.disk. From Windows, you can use http://ext2read.blogspot.com/ instead.

Revision history for this message
m (launch-spam) said : 		#4

Thanks for clarification , but
I am interested , where is the corruption problem.
- bug in NTFS itsefl ?
- bug in ubuntu component working with NTFS ?

As I know , file opened for writing should not corrupt even if hard shutdown unless its size is changing ( root.disk has fixed size all the time )

Revision history for this message
m (launch-spam) said : 		#5

Sorry for my impatience , but
I want try to discover more to fix ( if possible ).

First , I should discover , where is ( possible ) bug.
- N. T. filesystem ( Microsoft developers ? )
- way , that ubuntu works with NTFS ( mount.ntfs process ? )
- other component ?

Revision history for this message
bcbc (bcbc) said : 		#6

Unfortunately I cannot answer this.

In my opinion, with Wubi there is a greater possibility of corruption as the root.disk contains a virtual partition with its own operating system and files. And on top of this the root.disk is a single large file on ntfs. The writes are set to sync immediately to reduce the chance that a cached write is lost in the event of a power failure, however, there are a small - but constant - number of users I see on ubuntuforums.org and here, who somehow get corruption and find that Windows removes it. If it's just ext4 corruption then this shouldn't affect Windows, but since windows is removing the file, it's probably ntfs corruption (and maybe also ext4 corruption).

I don't know how you could determine the exact cause. I have run wubi in one form or another for a couple of years and never lost a root disk in this way. It might occur more where there is severe ntfs fragmentation - or maybe when there is also some ubuntu program that is hanging and preventing the system from writing files. Or maybe just from a power failure at the wrong time. Or a combination of all of these.

If you want developer feedback you'd have to create a bug: https://bugs.launchpad.net/wubi/+filebug

Revision history for this message
m (launch-spam) said : 		#7

Thanks again.
I reported as wise , as my current knowledge allowed it :-)