Re: BUG btrfs fi show displays stale btrfs volume

[Goffredo Baroncelli <kreijack@gmail.com>]

On 01/06/2013 05:26 PM, Goffredo Baroncelli wrote:
> Hi Chris
[...]
> 
> I will start to update the wiki; then I will give a look to wipefs to
> improve it.

Hello I updated the wiki page:


https://btrfs.wiki.kernel.org/index.php/Problem_FAQ#What_if_I_don.27t_have_wipefs_at_hand.3F
-----
 What if I don't have wipefs at hand?

There are three superblocks: the first one is located at 64K, the second
one at 64M, the third one at 256GB. The following lines reset the magic
string on all the three superblocks

# dd if=/dev/zero bs=1 count=8 of=/dev/sda seek=$((64*1024+64))
# dd if=/dev/zero bs=1 count=8 of=/dev/sda seek=$((64*1024*1024+64))
# dd if=/dev/zero bs=1 count=8 of=/dev/sda seek=$((256*1024*1024*1024+64))

If you want to restore the superblocks magic string,

# echo "_BHRfS_M" | dd bs=1 count=8 of=/dev/sda seek=$((64*1024+64))
# echo "_BHRfS_M" | dd bs=1 count=8 of=/dev/sda seek=$((64*1024*1024+64))
# echo "_BHRfS_M" | dd bs=1 count=8 of=/dev/sda
seek=$((256*1024*1024*1024+64))
------

> 
> BR
> G.Baroncelli


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