Date: Tue, 26 Apr 2011 10:50:17 +0300 From: Alexander Motin <mav@FreeBSD.org> To: Pawel Jakub Dawidek <pjd@FreeBSD.org> Cc: src-committers@freebsd.org, svn-src-all@freebsd.org, "Bjoern A. Zeeb" <bz@freebsd.org>, Robert Watson <rwatson@freebsd.org>, svn-src-head@freebsd.org, Warner Losh <imp@bsdimp.com> Subject: Re: 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 Message-ID: <4DB67939.6080301@FreeBSD.org> In-Reply-To: <20110426073517.GF2472@garage.freebsd.pl> References: <alpine.BSF.2.00.1104241140070.36270@fledge.watson.org> <4DB441B0.8020906@FreeBSD.org> <CD028561-B550-4896-BE65-7C827BE6A34A@FreeBSD.org> <20110425134531.GA4391@garage.freebsd.pl> <50385B7B-7EC8-4BC3-8F88-83F9EB4096FB@bsdimp.com> <4DB5A166.9010302@FreeBSD.org> <67F62848-FAA3-4C46-A95A-DA7C82281898@bsdimp.com> <4DB5B0A9.4030805@FreeBSD.org> <20110426070020.GC2472@garage.freebsd.pl> <4DB6721B.3020600@FreeBSD.org> <20110426073517.GF2472@garage.freebsd.pl>
next in thread | previous in thread | raw e-mail | index | archive | help
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
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?4DB67939.6080301>