volume.path and volume.export() refer to the same thing in lvm_thin and
'file', but not in file-reflink (where volume.path is the -dirty.img,
which doesn't exist if the volume is not started).
Use the file-reflink storage driver if /var/lib/qubes is on a filesystem
that supports reflinks, e.g. when the btrfs layout was selected in
Anaconda. If it doesn't support reflinks (or if detection fails, e.g. in
an unprivileged test environment), use 'file' as before.
_wait_and_reraise() is similar to asyncio.gather(), but it preserves the
current behavior of waiting for all futures and only _then_ reraising
the first exception (if there is any) in line.
Also switch Storage.create() and Storage.clone() to _wait_and_reraise().
Previously, they called asyncio.wait() and implicitly swallowed all
exceptions.
With that syntax, the default timestamp would have been from the time of
the function's definition (not invocation). But all callers are passing
an explicit timestamp anyway.
Convert create(), verify(), remove(), start(), stop(), revert(),
resize(), and import_volume() into coroutine methods, via a decorator
that runs them in the event loop's thread-based default executor.
This reduces UI hangs by unblocking the event loop, and can e.g. speed
up VM starts by starting multiple volumes in parallel.
Instead of raising a NotImplementedError, just return self like 'file'
and lvm_thin. This is needed when Storage.clone() is modified in another
commit* to no longer swallow exceptions.
* "storage: factor out _wait_and_reraise(); fix clone/create"
Import volume data to a new _path_import (instead of _path_dirty) before
committing to _path_clean. In case the computer crashes while an import
operation is running, the partially written file should not be attached
to Xen on the next volume startup.
Use <name>-import.img as the filename like 'file' does, to be compatible
with qubes.tests.api_admin/TC_00_VMs/test_510_vm_volume_import.
When the AT_REPLACE flag for linkat() finally lands in the Linux kernel,
_replace_file() can be modified to use unnamed (O_TMPFILE) tempfiles.
Until then, make sure stale tempfiles from previous crashes can't hang
around for too long.
It's sort of useful to be able to revert a volume that has only ever
been started once to its empty state. And the lvm_thin driver allows it
too, so why not.
System tests are fragile for any object leaks, especially those holding
open files. Instead of wrapping all tests with try/finally removing
those local variables (as done in qubes.tests.integ.backup for example),
apply generic solution: clean all traceback objects from local
variables. Those aren't used to generate text report by either test
runner (qubes.tests.run and nose2). If one wants to break into debugger
and inspect tracebacks interactively, needs to comment out call to
cleanup_traceback.
* qubesos/pr/228:
storage/lvm: filter out warning about intended over-provisioning
tests: fix getting kernel package version inside VM
tests/extra: add start_guid option to VMWrapper
vm/qubesvm: fire 'domain-start-failed' event even if fail was early
vm/qubesvm: check if all required devices are available before start
storage/lvm: fix reporting lvm command error
storage/lvm: save pool's revision_to_keep property
qubes-vm@.service would already cause this ordering, but not every user
has any autostart=True VMs.
Also needed to maybe f*x QubesOS/qubes-issues#3149 at some point.
