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From: Kay Sievers <kay.sievers@vrfy.org>
Date: Thu, 16 Jun 2011 19:20:07 +0200
Message-ID: <BANLkTikUNqTxgD_+TTVpcFyRDu_fSesrsg@mail.gmail.com>
Subject: Re: [PATCH 1/3] [RFC] genhd: add a new attribute in device structure
To: James Bottomley <James.Bottomley@hansenpartnership.com>
Cc: Greg KH <greg@kroah.com>, Nao Nishijima <nao.nishijima.xt@hitachi.com>,
        linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org,
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On Thu, Jun 16, 2011 at 19:09, Kay Sievers <kay.sievers@vrfy.org> wrote:
> On Thu, Jun 16, 2011 at 18:25, James Bottomley
> <James.Bottomley@hansenpartnership.com> wrote:
>> On Thu, 2011-06-16 at 09:14 -0700, Greg KH wrote:
>> > All userspace naming will be taken care of by the usual udev rules, so
>>> > for disks, something like /dev/disk/by-preferred/<fred> which would be
>>> > the usual symbolic link.
>>>
>>> No, udev can not create such a link after the preferred name is set, as
>>> it has no way of knowing that the name was set.
>>
>> It can if we trigger a uevent.  Note: I'm not advocating this ... I'd be
>> equally happy having whatever sets the kernel name create the link (or
>> tickle udev to create it).  We definitely require device links, though,
>> to get this to work.

Guess all that would work now, including mount(8) not canonicalizing.
What would happen if we mount:
  /dev/disk/by-pretty/foo
and some tool later thinks the pretty name should better be 'bar', it
writes the name to /sys, we get a uevent, the old link disappears, we
get a new link, mount has no device node anymore for the mounted
device ...

So we basically get a one-shot additional pretty name? Guess, the
_single_ name changed anytime later just asks for serious problems. We
need to set it very early to be really useful, but how, where is it
coming from?

Kay
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