This adds the file-reflink storage driver. It is never selected
automatically for pool creation, especially not the creation of
'varlibqubes' (though it can be used if set up manually).
The code is quite small:
reflink.py lvm.py file.py + block-snapshot
sloccount 334 lines 447 (134%) 570 (171%)
Background: btrfs and XFS (but not yet ZFS) support instant copies of
individual files through the 'FICLONE' ioctl behind 'cp --reflink'.
Which file-reflink uses to snapshot VM image files without an extra
device-mapper layer. All the snapshots are essentially freestanding;
there's no functional origin vs. snapshot distinction.
In contrast to 'file'-on-btrfs, file-reflink inherently avoids
CoW-on-CoW. Which is a bigger issue now on R4.0, where even AppVMs'
private volumes are CoW. (And turning off the lower, filesystem-level
CoW for 'file'-on-btrfs images would turn off data checksums too, i.e.
protection against bit rot.)
Also in contrast to 'file', all storage features are supported,
including
- any number of revisions_to_keep
- volume.revert()
- volume.is_outdated
- online fstrim/discard
Example tree of a file-reflink pool - *-dirty.img are connected to Xen:
- /var/lib/testpool/appvms/foo/volatile-dirty.img
- /var/lib/testpool/appvms/foo/root-dirty.img
- /var/lib/testpool/appvms/foo/root.img
- /var/lib/testpool/appvms/foo/private-dirty.img
- /var/lib/testpool/appvms/foo/private.img
- /var/lib/testpool/appvms/foo/private.img@2018-01-02T03:04:05Z
- /var/lib/testpool/appvms/foo/private.img@2018-01-02T04:05:06Z
- /var/lib/testpool/appvms/foo/private.img@2018-01-02T05:06:07Z
- /var/lib/testpool/appvms/bar/...
- /var/lib/testpool/appvms/...
- /var/lib/testpool/template-vms/fedora-26/...
- /var/lib/testpool/template-vms/...
It looks similar to a 'file' pool tree, and in fact file-reflink is
drop-in compatible:
$ qvm-shutdown --all --wait
$ systemctl stop qubesd
$ sed 's/ driver="file"/ driver="file-reflink"/g' -i.bak /var/lib/qubes/qubes.xml
$ systemctl start qubesd
$ sudo rm -f /path/to/pool/*/*/*-cow.img*
If the user tries to create a fresh file-reflink pool on a filesystem
that doesn't support reflinks, qvm-pool will abort and mention the
'setup_check=no' option. Which can be passed to force a fallback on
regular sparse copies, with of course lots of time/space overhead. The
same fallback code is also used when initially cloning a VM from a
foreign pool, or from another file-reflink pool on a different
mountpoint.
'journalctl -fu qubesd' will show all file-reflink copy/rename/remove
operations on VM creation/startup/shutdown/etc.
Support registering handlers for more flexible wildcard events: not only
'*', but also 'something*'. This allows to register handlers for
'property-set:*' and such.
Use '<option name="option_name">option_value</option>' instead of
'<options option_name="option_value"/>'. It's more consistent with the
rest of qubes.xml - have one thing per element.
Also, add options deserialization test.
This is rewritten version of core-admin-linux/qrexec/qrexec-policy.
It's placed outside of `qubes` module on purpose - to avoid imporing it,
which require a lot of time.
QubesOS/qubes-issues#865QubesOS/qubes-issues#910
None of properties set there do any "dangerous thing" for filesystem
permissions (at least for now), so do not require it. This is mostly to
keep compatibility with %post rpm scripts (kernel-qubes-vm at least).
QubesOS/qubes-issues#2412
* core3-devices:
Fix core2migration and tests for new devices API
tests: more qubes.devices tests
qubes/ext/pci: implement pci-no-strict-reset/BDF feature
qubes/tools: allow calling qvm-device as qvm-devclass (like qvm-pci)
qubes: make pylint happy
qubes/tools: add qvm-device tool (and tests)
tests: load qubes.tests.tools.qvm_ls
tests: PCI devices tests
tests: add context manager to catch stdout
qubes/ext/pci: move PCI devices handling to an extension
qubes/devices: use more detailed exceptions than just KeyError
qubes/devices: allow non-persistent attach
qubes/storage: misc fixes for VM-exposed block devices handling
qubes: new devices API
FixesQubesOS/qubes-issues#2257
Allow device plugin to list attached and available devices. Enforce
at API level every device being exposed by some domain.
This commit only changes devices API, but not update existing users
(pci) yet.
QubesOS/qubes-issues#2257
