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

[NeilBrown <neilb@suse.de>]

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On Sun, 09 Jan 2011 22:32:01 +0100 Vladimir 'φ-coder/phcoder' Serbinenko
<phcoder@gmail.com> wrote:

> 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
> 


Simply running
   mdadm --zero-superblock /dev/sdb

should fix it.

NeilBrown

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