[Ocfs2-users] Bad magic number in inode

[Sunil Mushran]

The quick detect just looks for the superblock which is in the third
block of the device. The full detect looks up the superblock and then
the system directory. In your case it fails to locate the latter.

This is one of the quirks when using an unpartitioned disk and later
partitioning it. The partitioning does not clear all the header blocks
that includes the fs superblock.

Long story short... use any binary editor (bvi), open the volume
and search for the OCFSV2 string. Change that signature.
Hint: It will be the first string in the third block. If you had formatted
with 4k blocksize, it will be on block starting at 8K, for 2k it will be
block starting at 4K.... you get the drift.

Marcel Savelkoul wrote:
> Hi,
>
> Pretty new here with SAN's and Oracle RAC.
> I had set up everything but because I wanted to enlarge one of the
> disks used I removed everything and started over and stumble upon the
> following:
>
> There is one disk defined on the SAN. This is /dev/sda.
> I haven't done fdisk yet so I also don't have /dev/sda1 yet.
>
> But if I now do the "mounted.ocfs2" command I see the following:
>
> # mounted.ocfs2 -d
> Device                FS     UUID                                  Label
> /dev/sda              ocfs2  6fe56000-97e6-4ea1-a302-29a8213c6e04  oradb
>
> # mounted.ocfs2 -f
> Device                FS     Nodes
> /dev/sda              ocfs2  Unknown: Bad magic number in inode
>
> This device is also listed when I check it with the ocfs2console.
>
> I tried to open it with debug but then I get this:
>
> # mount -t debugfs debugfs /debug
> # echo "fs_locks" | debugfs.ocfs2 /dev/sda >/tmp/fslocks
> debugfs.ocfs2 1.2.2
> Could not open debug state for "6FE5600097E64EA1A30229A8213C6E04".
> Perhaps that OCFS2 file system is not mounted?
>
> If I now use fdisk to create a partition on the device /dev/sda I see the
> following with the "mounted.ocfs2" command:
>
> # mounted.ocfs2 -f
> Device                FS     Nodes
> /dev/sdc              ocfs2  Unknown: Bad magic number in inode
> /dev/sdc1             ocfs2  Not mounted
>
> Now the /dev/sda isn't listed anymore in the ocfs2console but the 
> /dev/sda1
> is and after actually mounting the /dev/sdc1 I see:
>
> # mounted.ocfs2 -f
> Device                FS     Nodes
> /dev/sda              ocfs2  Unknown: Bad magic number in inode
> /dev/sda1             ocfs2  pub.host.com
>
> Why do I keep seeing the /dev/sda device?
>
> Best Regards,
>
> Marcel
>
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