Re: btrfs subvolume clone or fork (btrfs-progs feature request)

[Duncan <1i5t5.duncan@cox.net>]

Austin S Hemmelgarn posted on Thu, 09 Jul 2015 08:48:00 -0400 as
excerpted:

> On 2015-07-09 08:41, Sander wrote:
>> Austin S Hemmelgarn wrote (ao):
>>>> What's wrong with "btrfs subvolume snapshot"?
>>>
>>> Well, personally I would say the fact that once something is tagged as
>>> a snapshot, you can't change it to a regular subvolume without doing a
>>> non-incremental send/receive.
>>
>> A snapshot is a subvolume. There is no such thing as "tagged as a
>> snapshot".
>>
>> 	Sander
>>
> No, there is a bit in the subvolume metadata that says whether it's
> considered a snapshot or not.  Internally, they are handled identically,
> but it does come into play when you consider things like btrfs subvolume
> show -s (which only lists snapshots), which in turn means that certain
> tasks are more difficult to script robustly.

My use-case doesn't involve subvolumes or snapshots so I can't check for 
sure, but...

I could have sworn btrfs property -t subvolume can get/set that snapshot 
bit.  I know I saw the discussion and I think patch for it go by, but 
again, as I don't use them, I haven't tracked closely enough to see if it 
ever got in.

-- 
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"Every nonfree program has a lord, a master --
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