[lvm-devel] [PATCH] lvcreate: support --force option

[Zdenek Kabelac]

Dne 26.10.2015 v 11:07 Lidong Zhong napsal(a):
> Hi Zdenek,
>
>>>> On 10/12/2015 at 05:02 PM, in message <561B7728.5010804 at redhat.com>, Zdenek
> Kabelac <zkabelac at redhat.com> wrote:
>> Dne 12.10.2015 v 04:26 Lidong Zhong napsal(a):
>>> Hi Zdenek,
>>>
>>> Thanks for your reply.
>>>
>>>>>> On 10/10/2015 at 09:17 PM, in message <56190FE5.1030900 at redhat.com>, Zdenek
>>> Kabelac <zkabelac at redhat.com> wrote:
>>>> Dne 10.10.2015 v 12:39 Lidong Zhong napsal(a):
>>>>> The option is supported in the logic of lvcreate but is omitted in
>>>>> commands.h.
>>>>>
>>>>
>>>> Nope - it's not intended to be unsupported so far.
>>>>
>>>> We do support --yes  to overcome prompts.
>>>>
>>>> Normally --force is meant to be used on paths to proceed with
>>>> i.e. lvremove, lvconvert
>>>>
>>>> Do you have any case in mind where '--force' with lvcreate would have make
>> any
>>>>
>>>> sense ?
>>>
>>> Not really. I met this problem when I was using lvcreate with the
>> --wipesignature option.
>
> If we set the --wipesignature to y while creating an lv, there will be a prompt for confirming
> in current code. Doesn't it make more sense that there shouldn't be the prompt? since we
> definitely want to remove the signature by setting this option.
> Some options such as "--zero=y" don't give prompt, why it is different?
> Please give your opinion.
>


Hi


Here is explanation.

'zero' is unconditional and does not detect any signature - so it has nothing 
to prompt about - it zeroes first 4K as that's what user asked for.

New 'wipesignature' first detects signature and asks if you want to wipe.
That's the API (and it's very similar to e.g. mkfs)

If lvm2 knows its overwriting something it prompts - that's the rule.

If you are going to take a 'risk' for no prompting - use  '--yes'

lvm2 is possibly missing couple prompts - so you could possibly open BZ for 
the case we convert/overwrite something without prompting first.

But existing prompts will remain as they are as they are correct.

Regards

Zdenek