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In certain rare occasions qemu can transition a block job which was
already 'ready' into 'standby' and then back. If this happens in the
following order libvirt will get confused about the actual job state:
1) the block copy job is 'ready' (job->state == QEMU_BLOCKJOB_STATE_READY)
2) user calls qemuDomainBlockJobAbort with VIR_DOMAIN_BLOCK_JOB_ABORT_PIVOT
flag but without VIR_DOMAIN_BLOCK_JOB_ABORT_ASYNC
3) the block job is switched to synchronous event handling
4) the block job blips to 'standby' and back to 'ready', the event is
not processed since the blockjob is in sync mode for now
5) qemuDomainBlockJobPivot is called:
5.1) 'job-complete' QMP command is issued
5.2) job->state is set to QEMU_BLOCKJOB_STATE_PIVOTING
6) code for synchronous-wait for the job completion in qemuDomainBlockJobAbort
is invoked
7) the waiting loop calls qemuBlockJobUpdate:
7.1) job->newstate is QEMU_BLOCKJOB_STATE_READY due to 4)
7.2) qemuBlockJobEventProcess is called
7.3) the handler for QEMU_BLOCKJOB_STATE_READY overwrites
job->state from QEMU_BLOCKJOB_STATE_PIVOTING to QEMU_BLOCKJOB_STATE_READY
8) qemuDomainBlockJobAbort is looking for a finished job, so waits again
9) qemu finishes the blockjob and transitions it into 'concluded' state
10) qemuBlockJobUpdate is triggered again, this time finalizing the job.
10.1) job->newstate is = QEMU_BLOCKJOB_STATE_CONCLUDED
job->state is = QEMU_BLOCKJOB_STATE_READY
10.2) qemuBlockJobEventProcessConcluded is called, the function
checks whether there was an error with the blockjob. Since
there was no error job->newstate becomes
QEMU_BLOCKJOB_STATE_COMPLETED.
10.3) qemuBlockJobEventProcessConcludedTransition selects the action
for the appropriate block job type where we have:
case QEMU_BLOCKJOB_TYPE_COPY:
if (job->state == QEMU_BLOCKJOB_STATE_PIVOTING && success)
qemuBlockJobProcessEventConcludedCopyPivot(driver, vm, job, asyncJob);
else
qemuBlockJobProcessEventConcludedCopyAbort(driver, vm, job, asyncJob);
break;
Since job->state is QEMU_BLOCKJOB_STATE_READY,
qemuBlockJobProcessEventConcludedCopyAbort is called.
This patch forbids transitions to QEMU_BLOCKJOB_STATE_READY if the
previous job state isn't QEMU_BLOCKJOB_STATE_RUNNING or
QEMU_BLOCKJOB_STATE_NEW.
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1951507
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
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==============================
Libvirt API for virtualization
==============================
Libvirt provides a portable, long term stable C API for managing the
virtualization technologies provided by many operating systems. It
includes support for QEMU, KVM, Xen, LXC, bhyve, Virtuozzo, VMware
vCenter and ESX, VMware Desktop, Hyper-V, VirtualBox and the POWER
Hypervisor.
For some of these hypervisors, it provides a stateful management
daemon which runs on the virtualization host allowing access to the
API both by non-privileged local users and remote users.
Layered packages provide bindings of the libvirt C API into other
languages including Python, Perl, PHP, Go, Java, OCaml, as well as
mappings into object systems such as GObject, CIM and SNMP.
Further information about the libvirt project can be found on the
website:
https://libvirt.org
License
=======
The libvirt C API is distributed under the terms of GNU Lesser General
Public License, version 2.1 (or later). Some parts of the code that are
not part of the C library may have the more restrictive GNU General
Public License, version 2.0 (or later). See the files ``COPYING.LESSER``
and ``COPYING`` for full license terms & conditions.
Installation
============
Instructions on building and installing libvirt can be found on the website:
https://libvirt.org/compiling.html
Contributing
============
The libvirt project welcomes contributions in many ways. For most components
the best way to contribute is to send patches to the primary development
mailing list. Further guidance on this can be found on the website:
https://libvirt.org/contribute.html
Contact
=======
The libvirt project has two primary mailing lists:
* libvirt-users@redhat.com (**for user discussions**)
* libvir-list@redhat.com (**for development only**)
Further details on contacting the project are available on the website:
https://libvirt.org/contact.html