svn commit: r220982 - in head: . sys/amd64/conf sys/arm/conf sys/conf sys/i386/conf sys/ia64/conf sys/mips/conf sys/mips/malta sys/pc98/conf sys/powerpc/conf sys/sparc64/conf sys/sun4v/conf

[Alexander Motin]

On 26.04.2011 10:35, Pawel Jakub Dawidek wrote:
> On Tue, Apr 26, 2011 at 10:19:55AM +0300, Alexander Motin wrote:
>> On 26.04.2011 10:00, Pawel Jakub Dawidek wrote:
>>> On Mon, Apr 25, 2011 at 08:34:33PM +0300, Alexander Motin wrote:
>>>> I've thought about the process of fixing hardcoded provider names there,
>>>> and it is absolutely not trivial. If we take the "symlinking" way (patch
>>>> is already posted to current@), I think it will be much easier for
>>>> everybody, and especially users, if I hack all mentioned above GEOM
>>>> classes to ignore adX/adaY difference in provider names. And it should
>>>> perfectly fit into remaining time window.
>>>
>>> Could you be more specific what the hack would do exactly?
>>
>> I would write some comparison function, which would search both
>> names for adX/adaY prefixes, if they found on both arguments,
>> trimmed them and compared remaining parts.
>>
>> I think for usual purpose of name hardcoding device name part is
>> less important. Comparing partition names part should be enough. The
>> tricky part there is to properly identify device part, so I was
>> thinking about specific hack for adX/adaY.
>
> I was wondering how would you match X and Y, but this is indeed not
> important. So on taste we could do (totally untested):
>
> static bool
> provider_name_matches(const char *ppname, const char *hcname)
> {
>
> 	if (strcmp(ppname, hcname) == 0)
> 		return (true);
> 	if (strncmp(hcname, "ad", 2) != 0 ||
> 	    hcname[2]<  '0' || hcname[2]>  '9') {
> 		return (false);
> 	}
> 	if (strncmp(ppname, "ada", 3) != 0 ||
> 	    ppname[3]<  '0' || ppname[3]>  '9') {
> 		return (false);
> 	}
> 	/* Skip 'ad[0-9]+'. */
> 	hcname += 3;
> 	while (hcname[0]>= '0'&&  hcname[0]<= '9')
> 		hcname++;
> 	/* Skip 'ada[0-9]+'.
> 	ppname += 4;
> 	while (ppname[0]>= '0'&&  ppname[0]<= '9')
> 		ppname++;
>
> 	return (strcmp(ppname, hcname) == 0);
> }
>
> That could work.

Yes, I was thinking about something like that. May be just symmetric, so 
it could handle some cases of downgrade.

> Another possibility I was thinking of was to create GEOM providers for
> both names and orphan the other name once one of them is opened for
> writing.

I've even implemented patch (posted on current@) with close idea (I was 
creating extra geom with legacy name), and it will have the same 
problem: if somebody open any partition on the device with the new name, 
all legacy names will become inaccessible (busy), and vice versa. It 
could be not a big problem if it would only be user's choice -- we could 
say just: "use one or another, not both". But provider could be chosen 
blindly by some GEOM class, such as glabel, and then it turns into pure 
lottery.

-- 
Alexander Motin