Re: [PATCH] Refuse to install on XFS destroying its superblock

[Vladimir 'phcoder' Serbinenko]

Robert Millan wrote:
> On Fri, Oct 16, 2009 at 10:09:41PM +0200, Vladimir 'phcoder' Serbinenko wrote:
>   
>> Robert Millan wrote:
>>     
>>> On Fri, Oct 16, 2009 at 06:01:56PM +0200, Jordi Mallach wrote:
>>>   
>>>       
>>>> On Fri, Oct 16, 2009 at 04:03:01PM +0200, Vladimir 'phcoder' Serbinenko 
>>>> wrote:
>>>>     
>>>>         
>>>>> +  if (memcmp (tmp_img, "XFSB", 4) == 0)
>>>>> +    grub_util_error ("Can't install on XFS.");
>>>>>       
>>>>>           
>>>> Can this error message give some more detail on what the problem is?
>>>>     
>>>>         
>>> I suggest something like:
>>>
>>>   grub_util_warn ("Refusing to overwrite XFS meta-data.");
>>>
>>> This is more informative, and with grub_util_warn() user has an opportunity 
>>> to
>>> override it if she knows what she's doing.
>>>
>>>   
>>>       
>> Installing with blocklists/to partition is considered
>> backward-compatibility feature. We never supported a config with XFS why
>> we would want bw-compat for it?
>>     
>
> Because we can't reliably tell if it's a config with XFS, only the user can.
> This is an issue for both MBR or PBR installs.
>
> Maybe "XFSB" is only a remnant from one of this disk / partition former
> lifes.  Maybe it's a valid XFS but user no longer cares about it.  Or
> maybe a DOS-style label was created on top of it, without overwriting the 
> first
> 440 bytes.  Or maybe another filesystem had overwritten most XFS metadata
> but preserved the first block (this is conceivable since other filesystems
> tend to avoid using the first block).
>
> If user has to workaround GRUB heuristics by dd'ing zeros into a partition
> before running grub-install, this is a sign GRUB isn't doing the right thing.
>
>   
Well, ok. But then I would ask to use a separate --force e.g.
--force-destroy-xfs since users and distributions tend to use --force
too much

-- 
Regards
Vladimir 'phcoder' Serbinenko
Personal git repository: http://repo.or.cz/w/grub2/phcoder.git