On Thu, Oct 15, 2015 at 05:30:15PM +0200, Martin Vidner wrote:

> What is a Holder? It seems to be characterized by having a source
> sid and a target sid, which still does not give me a hint.
> Its subclasses Subdevice and User are even more opaque to me.

Technical it's the edge in the graph, so it expresses what device
is linked what device. The name I have borrowed from sysfs (but
it's not the same as in sysfs), e.g. on my system I have
(simplified)

# ll /sys/block/sda/sda2/holders/
lrwxrwxrwx 1 root root 0 Oct 15 17:17 dm-0 -> 
../../../../../../../../../../virtual/block/dm-0
lrwxrwxrwx 1 root root 0 Oct 15 17:17 dm-1 -> 
../../../../../../../../../../virtual/block/dm-1

In the graph there are different holders.

- Subdevice: E.g. a partition is the subdevice of a Disk and a
  logical volume is the subdevice of a volume group.

- User: E.g. a partition is used by a volume group (the case on
  my system), a disk is used by a RAID, a logical volume is used
  by a filesystem.

So far the distinction is not really important so it could
change.

> Environment sounds like a candidate for a kitchen sink of unrelated
> hacks. Can we describe it with the purpose of limiting its scope?

Yes, we should define its purpose.

> Devicegraph should be renamed to DeviceGraph. It just isn't a single
> word.

Fine for me.

> Why is there Storage::copy_devicegraph if Devicegraph is_a
> noncopyable?

Devicegraph has a copy function. Replacing the copy function by
standard copy and assignment operators should be possible.
 
> The "Encryption" name is bothering me because encryption is a
> concept whereas all the other subclasses of Device are things.

Is "Crypt", "CryptDevice" or "EncryptedDevice" better for you?

> storage::Disk::get_transport returns a storage_legacy::Transport. A
> "modern" object returning a "legacy" object does not feel right, but
> I don't know enough to suggest an alternative.

Some enums are used in the legacy and the new interface. Defining
them twice is bad so for the time being I use the legacy
namespace. Nothing more.

ciao Arvin

-- 
Arvin Schnell, <[email protected]>
Senior Software Engineer, Research & Development
SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 
(AG Nürnberg)
Maxfeldstraße 5
90409 Nürnberg
Germany
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