Re: Bug#597563: grub-common: grub-probe segfaults scanning lvm devices

["Vladimir 'φ-coder/phcoder' Serbinenko" <phcoder@gmail.com>]

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On 01/09/2011 09:55 PM, NeilBrown wrote:
> On Sat, 8 Jan 2011 17:53:07 -0500 (EST) Matthew Gabeler-Lee
> <cheetah@cheetah.fastcat.org> wrote:
>
>   
>> On Sat, 8 Jan 2011, Vladimir 'φ-coder/phcoder' Serbinenko wrote:
>>
>>     
>>> As was recommended I forward the remaining part to linux-raid mailing list.
>>> In short: on his system mdraid, raid5, 4 devices, metadata (presumably)
>>> 0.90, two devices have index 0.
>>>       
> What do you mean by "two devices have index 0" ??? I could see nothing in any
> of the posts you sent that could be interpreted that way.
>
>   
Sorry, I forgot this part:
grub-core/disk/raid.c:699: Scanning for RAID devices on disk hd2
grub-core/kern/disk.c:245: Opening `hd2'...
./grub-probe: info: the size of hd2 is 1465149168.
error: found two disks with the number 0.
grub-core/kern/disk.c:330: Closing `hd2'.

Trouble comes from followint part:
$ sudo mdadm --examine /dev/sdb
/dev/sdb:
          Magic : a92b4efc
        Version : 0.90.03
           UUID : 9364f7a2:d74695d5:7d8db3a0:3b5f9e48
  Creation Time : Mon Mar 27 14:03:04 2006
     Raid Level : raid1
  Used Dev Size : 979840 (957.04 MiB 1003.36 MB)
     Array Size : 979840 (957.04 MiB 1003.36 MB)
   Raid Devices : 2
  Total Devices : 3
Preferred Minor : 0

    Update Time : Thu Jan  8 00:34:39 2009
          State : clean
 Active Devices : 2
Working Devices : 3
 Failed Devices : 0
  Spare Devices : 1
       Checksum : 5b8134eb - correct
         Events : 9446738
So sdb as whole pretends to be a part of the following array:
$ sudo mdadm -QD /dev/md0
/dev/md0:
        Version : 0.90
  Creation Time : Mon Mar 27 14:03:04 2006
     Raid Level : raid1
     Array Size : 2008000 (1961.27 MiB 2056.19 MB)
  Used Dev Size : 2008000 (1961.27 MiB 2056.19 MB)
   Raid Devices : 4
  Total Devices : 4
Preferred Minor : 0
    Persistence : Superblock is persistent

    Update Time : Sat Jan  8 18:35:47 2011
          State : clean
 Active Devices : 4
Working Devices : 4
 Failed Devices : 0
  Spare Devices : 0

           UUID : 9364f7a2:d74695d5:7d8db3a0:3b5f9e48
         Events : 0.10758124

    Number   Major   Minor   RaidDevice State
       0       8       17        0      active sync   /dev/sdb1
       1       8       33        1      active sync   /dev/sdc1
       2       8        1        2      active sync   /dev/sda1
       3       8       49        3      active sync   /dev/sdd1


As you can see there is a stalled superblock approximately 2 years old.
I don't know if it's some kind of freak accident or operator error. If
it's later then probably zero-filling over stalled superblock will solve
the problems

-- 
Regards
Vladimir 'φ-coder/phcoder' Serbinenko



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