Re: fsck_ext2fs coredump

[Jasper Wallace <jasper%pointless.net@localhost>]

On Fri, 2 Sep 2011, Patrick Welche wrote:

> Trying to fix an ailing ubuntu box by netbooting NetBSD, I got a coredump
> on:
> 
> #        size    offset     fstype [fsize bsize cpg/sgs]
>  d: 1953525168         0     unused      0     0        # (Cyl.      0 - 
> 1938020)
>  e: 976751937        63 Linux Ext2      0     0        # (Cyl.      0*- 
> 968999)
>  f: 976768065 976752000 Linux Ext2      0     0        # (Cyl. 969000 - 
> 1938015*)
> 
> # fsck /dev/rwd1f
> fsck: Cannot open `/etc/fstab': No such file or directory
> fsck: Cannot open `/etc/fstab': No such file or directory
> ** /dev/rwd1f
> BAD SUPER BLOCK: INCOMPATIBLE FEATURE BITS IN SUPER BLOCK
> fsck: /dev/rwd1f: Floating point exception
> 
> Program terminated with signal 8, Arithmetic exception.
> #0  0x080528b2 in calcsb (dev=0x8056440 "/dev/rwd1f", devfd=3, fs=0xbfbfdd84)
>     at /usr/src/sbin/fsck_ext2fs/setup.c:496
> 496             fs->e2fs.e2fs_bcount = (pp->p_size * DEV_BSIZE) / 
> fs->e2fs_bsize;
> 
> which isn't too surprising as *fs is just made up of zeros.
> 
> Should I conclude that all the super blocks just contain zeros and this
> disk is beyond rescue?

The "INCOMPATIBLE FEATURE BITS IN SUPER BLOCK" is presumably from the 
first superblock, and zero'd ones are presumably the alternate ones, this 
might be related to PR/45072 (which i'm way overdue to update).

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