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Date: Wed, 13 Oct 2010 11:10:37 +0300
From: Andriy Gapon <avg@icyb.net.ua>
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To: Stefan Bethke <stb@lassitu.de>
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Cc: stable@freebsd.org, "Andrey V. Elsukov" <bu7cher@yandex.ru>
Subject: Re: Label question...why does ufs label vanish on mount?
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on 13/10/2010 09:29 Stefan Bethke said the following:
> Am 13.10.2010 um 06:56 schrieb Andrey V. Elsukov:
>> When you are opening provider for writing (i.e. mount FS) GEOM(4) initiates
>> SPOILING and all consumers that are attached to this provider except one
>> will self-destroyed. When you are closing provider GEOM(4) initiates
>> TASTING and consumers can return back. Look at man 4 geom for details.
> 
> That explains the mechanism, but not the rationale.  Or is it just an
> unintended consequence?  And how is da2p1 different from ufs/mylabel?  (Mount
> da2p1 and ufs/mylabel is removed, but not the other way around.)

da2p1 is a "real" underlying provider, "ufs/mylabel" is a "convenience" provider
on _top_ of it.
When you open a top-most provider it doesn't affect provides under it.
If you open a provider down the chain, then the providers above it are spoiled.
Does it make sense now?

-- 
Andriy Gapon