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[linux-lvm] Inconsistent naming needs to be fixed (was Re: Inconsistent naming...?)



Linda A. Walsh wrote:

> Alasdair G Kergon wrote:
>> On Sun, Jul 10, 2011 at 06:31:27PM -0700, Linda A. Walsh wrote:
>>> Notice the device name.   notice how the single dashes are now
>>> displayed as two dashes?!?! >> Roughly: a dash is the separator we chose, and we double it to escape a
>> real dash.  But we still need to extend our escaping mechanism to handle
>> characters that udev states it doesn't support in primary device names
>> but which the old /dev did used to support (and so we still do).
>
>    Roughly, if I give a script the mount point of a logical device, how
>    can I find out the name of the LV it is on?

  Ok, I think I bass-ackwards way of hacking around this -- but my
  solution is unique to my usage and conventions.

  In my 'application' (meaning 'usage'), I start with a mount-point
of a volume I want to take a snapshot of. I want to map that mount
point back to the original dev.  It's not straightforward when the
device in /proc/mounts, isn't the real device NOR is it the name I
used!   I.e. real dev = /dev/dm-[0-x], name i used /dev/VG/LV.
What /proc/mounts shows:  /mapper/dev/<mangled VG>-<mangled LV>.

  So who's responsible for that mess of code so we can get /proc to
either, show the value I used (when I mount by LABEL I see the 'real'
devices in mounts -- not /dev/disk-by-label/<label>.   It isn't consistent
but it's worse, as it choose a name that's gone through some
'translation'...


  Am I being more clear about why this create problems (besides
being confusing and just looking bad (because my computer has
to come up with it's own name for a dev -- neither the one
I used nor the real name?
  Now, I can kludge around this, by knowing some different pieces
of information unique to my app/situation, but in the general case,
it would be unpredictable, and that's bad, as I'd like to release these
scripts if I can get them working to my satisfaction.

   Can the situation with /proc/mounts be fixed?





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