Add convenient collection wrapper for easier getting selected volume.
Storage pool implementation may still provide only volume listing
function (pool.list_volumes), or, additionally, optimized
pool.get_volume.
This means it is both possible to iterate over volumes:
```python
for volume in pool.volumes:
...
```
And get a single volume:
```python
volume = pool.volumes[vid]
```
QubesOS/qubes-issues#2256
Reference objects, not their IDs - this way when object is modified, it
is visible everywhere where it is used. Main changes:
- volume.pool - Pool object
- volume.source - Volume object
Since volume have Pool object reference now, move volume related
functions into Volume class (from Pool class). This avoids horrible
`storage.get_pool(volume).something(volume)` construct.
One issue here is since volume.source reference a Volume object from a
different VM - VM's template, now VM load order is important. Since we
don't have control over it, initialize vm.storage when needed - possibly
while initializing storage of different VM. Since we don't have cycles
in AppVM-TemplateVM dependencies, it is safe.
Also, since this commit, volume.source (if defined) always points at
volume of the same name from VM's template. Using volumes with something
else as a source is no longer supported.
QubesOS/qubes-issues#2256
When VM is renamed only volume.vid get updated, but not other attributes
calculated from it. Convert them to dynamic properties to not worry
about it.
QubesOS/qubes-issues#2256
Allow importing not only from another volume, but also raw data. In
practice, for all currently implemented storage pools, this is the same
as Pool.export, because path returned there is read-write. But lets not
abuse this fact, some future implementation may need different methods.
QubesOS/qubes-issues#2622QubesOS/qubes-issues#2256
In case of LVM (at least), "internal" flag is initialized only when
listing volume attached to given VM, but not when listing them from the
pool. This looks like a limitation (bug?) of pool driver, it looks like
much nicer fix is to handle the flag in qvm-block tool (which list VMs
volumes anyway), than in LVM storage pool driver (which would need to
keep second copy of volumes list - just like file driver).
QubesOS/qubes-issues#2256
There are mutiple cases when snapshots are inconsistently created, for
example:
- "-back" snapshot created from the "new" data, instead of old one
- "-snap" created even when volume.snap_on_start=False
- probably more
Fix this by following volume.snap_on_start and volume.save_on_stop
directly, instead of using abstraction of old volume types.
QubesOS/qubes-issues#2256
- add missing lvm remove call when commiting changes
- delay creating volatile image until domain startup (it will be created
then anyway)
- reset cache only when really changed anything
- attach VM to the volume (snapshot) created for its runtime - to not
expose changes (for example in root volume) to child VMs until
shutdown
QubesOS/qubes-issues#2412QubesOS/qubes-issues#2256
The wrapper doesn't do anything else than translating command
parameters, but it's load time is significant (because of python imports
mostly). Since we can't use python lvm API from non-root user anyway,
lets drop the wrapper and call `lvm` directly (or through sudo when
necessary).
This makes VM startup much faster - storage preparation is down from
over 10s to about 3s.
QubesOS/qubes-issues#2256
...instead of manual copy in python. DD is much faster and when used
with `conv=sparse` it will correctly preserve sparse image.
QubesOS/qubes-issues#2256
1. Add a helper function on vm.storage. This is equivalent of:
vm.storage.get_pool(vm.volumes[name]).export(vm.volumes[name])
2. Make sure the path returned by `export` on LVM volume is accessible.
