When sending SIGHUP to libvirtd, it will trigger the virStateDriver
reload operation. This is intended to reload the configuration files
for guests. For unknown historical reasons this is also triggering
autostart of all guests. Autostart is generally expected to be
something that happens on OS startup. Starting VMs on SIGHUP will
violate that expectation and potentially cause dangerous scenarios
if the admin has explicitly shutdown a misbehaving VM that has
been marked as autostart
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Introduce new members in the virMacAddr 'class'
- virMacAddrSet: set virMacAddr from a virMacAddr
- virMacAddrSetRaw: setting virMacAddr from raw 6 byte MAC address buffer
- virMacAddrGetRaw: writing virMacAddr into raw 6 byte MAC address buffer
- virMacAddrCmp: comparing two virMacAddr
- virMacAddrCmpRaw: comparing a virMacAddr with a raw 6 byte MAC address buffer
then replace raw MAC addresses by replacing
- 'unsigned char *' with virMacAddrPtr
- 'unsigned char ... [VIR_MAC_BUFLEN]' with virMacAddr
and introduce usage of above functions where necessary.
If QEMU supports the BALLOON_EVENT QMP event, then we can
avoid invoking 'query-balloon' when returning XML or the
domain info.
* src/qemu/qemu_capabilities.c, src/qemu/qemu_capabilities.h:
Add QEMU_CAPS_BALLOON_EVENT
* src/qemu/qemu_driver.c: Skip query-balloon in
qemudDomainGetInfo and qemuDomainGetXMLDesc if we have
QEMU_CAPS_BALLOON_EVENT set
* src/qemu/qemu_monitor.c, src/qemu/qemu_monitor.h: Check
for BALLOON_EVENT at connect to monitor. Add callback
for balloon change notifications
* src/qemu/qemu_monitor_json.c, src/qemu/qemu_monitor_json.h:
Add handling of BALLOON_EVENT and impl 'query-events'
check
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
This is in preparation of the enablement of s390 guests with virtio devices.
The assignment of device addresses happens in different places, i.e. the
qemu driver and process modules as well as in the unit tests in slightly
different flavors. Currently, these are PPC spapr-vio and PCI
devices, virtio-s390 (not PCI based) will follow.
By optionally passing to qemuDomainAssignAddresses the domain
object and the capabilities it is now possible to call the function
from most of the places (except for hotplug) where address assignment
is done.
Signed-off-by: Viktor Mihajlovski <mihajlov@linux.vnet.ibm.com>
The only useful translation of "%s" as a format string is "%s" (I
suppose you could claim "%1$s" is also valid, but why bother). So
it is not worth translating; fixing this exposes some instances
where we were failing to translate real error messages. This makes
the fix of commit 097da1ab more generic, as well as ensuring no
future regressions.
* cfg.mk (sc_prohibit_useless_translation): New rule.
* src/lxc/lxc_driver.c (lxcSetVcpuBWLive): Fix offender.
* src/openvz/openvz_conf.c (openvzReadFSConf): Likewise.
* src/qemu/qemu_cgroup.c (qemuSetupCgroupForVcpu): Likewise.
* src/qemu/qemu_driver.c (qemuSetVcpusBWLive): Likewise.
* src/xenapi/xenapi_utils.c (xenapiSessionErrorHandle): Likewise.
QEMU domains were marked as having managed save image even if they were
saved using the regular save. With this patch, domains are marked so
only when using managed save API.
This patch adds support for listing all domains into drivers that use
the common virDomainObj implementation: libxl, lxc, openvz, qemu, test,
uml, vmware.
For drivers that don't support managed save images the guests are
treated as if they had none, so filtering guests that do have such an
image on this driver succeeds and produces 0 results.
The two new functions are very similar to the existing functions;
just a matter of different arguments and a call to a different
helper function.
* src/qemu/qemu_driver.c (qemuDomainSnapshotListNames)
(qemuDomainSnapshotNum, qemuDomainSnapshotListChildrenNames)
(qemuDomainSnapshotNumChildren): Support new flags.
(qemuDomainListAllSnapshots): New functions.
Now that domain listing is a thin wrapper around child listing,
it's easier to have a common entry point. This restores the
hashForEach optimization lost in the previous patch when there
are no snapshots being filtered out of the entire list.
* src/conf/domain_conf.h (virDomainSnapshotObjListGetNames)
(virDomainSnapshotObjListNum): Add parameter.
(virDomainSnapshotObjListGetNamesFrom)
(virDomainSnapshotObjListNumFrom): Delete.
* src/libvirt_private.syms (domain_conf.h): Drop deleted functions.
* src/conf/domain_conf.c (virDomainSnapshotObjListGetNames):
Merge, and (re)add an optimization.
* src/qemu/qemu_driver.c (qemuDomainUndefineFlags)
(qemuDomainSnapshotListNames, qemuDomainSnapshotNum)
(qemuDomainSnapshotListChildrenNames)
(qemuDomainSnapshotNumChildren): Update callers.
* src/qemu/qemu_migration.c (qemuMigrationIsAllowed): Likewise.
* src/conf/virdomainlist.c (virDomainListPopulate): Likewise.
This idea was first suggested by Daniel Veillard here:
https://www.redhat.com/archives/libvir-list/2011-October/msg00353.html
Now that I am about to add more complexity to snapshot listing, it
makes sense to avoid code duplication and special casing for domain
listing (all snapshots) vs. snapshot listing (descendants); adding
a metaroot reduces the number of code lines by having the domain
listing turn into a descendant listing of the metaroot.
Note that this has one minor pessimization - if we are going to list
ALL snapshots without filtering, then virHashForeach is more efficient
than recursing through the child relationships; restoring that minor
optimization will occur in the next patch.
* src/conf/domain_conf.h (_virDomainSnapshotObj)
(_virDomainSnapshotObjList): Repurpose some fields.
(virDomainSnapshotDropParent): Drop unused parameter.
* src/conf/domain_conf.c (virDomainSnapshotObjListGetNames)
(virDomainSnapshotObjListCount): Simplify.
(virDomainSnapshotFindByName, virDomainSnapshotSetRelations)
(virDomainSnapshotDropParent): Match new field semantics.
* src/qemu/qemu_driver.c (qemuDomainSnapshotCreateXML)
(qemuDomainSnapshotReparentChildren, qemuDomainSnapshotDelete):
Adjust clients.
This patch stores existence of the image in the object. At start of the
daemon the state is checked and then updated in key moments in domain
lifecycle.
The two APIs are rather trivial; based on bits and pieces of other
existing APIs. It leaves the door open for future extension to
qemu to report snapshots without metadata based on reading qcow2
internal snapshot names.
* src/qemu/qemu_driver.c (qemuDomainSnapshotIsCurrent)
(qemuDomainSnapshotHasMetadata): New functions.
==3240== 23 bytes in 1 blocks are definitely lost in loss record 242 of 744
==3240== at 0x4C2A4CD: malloc (vg_replace_malloc.c:236)
==3240== by 0x8077537: __vasprintf_chk (vasprintf_chk.c:82)
==3240== by 0x509C677: virVasprintf (stdio2.h:199)
==3240== by 0x509C733: virAsprintf (util.c:1912)
==3240== by 0x1906583A: qemudStartup (qemu_driver.c:679)
==3240== by 0x511991D: virStateInitialize (libvirt.c:809)
==3240== by 0x40CD84: daemonRunStateInit (libvirtd.c:751)
==3240== by 0x5098745: virThreadHelper (threads-pthread.c:161)
==3240== by 0x7953D8F: start_thread (pthread_create.c:309)
==3240== by 0x805FF5C: clone (clone.S:115)
Remove the uid param from virGetUserConfigDirectory,
virGetUserCacheDirectory, virGetUserRuntimeDirectory,
and virGetUserDirectory
These functions were universally called with the
results of getuid() or geteuid(). To make it practical
to port to Win32, remove the uid parameter and hardcode
geteuid()
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
When the last reference to a virConnectPtr is released by
libvirtd, it was possible for a deadlock to occur in the
virDomainEventState functions. The virDomainEventStatePtr
holds a reference on virConnectPtr for each registered
callback. When removing a callback, the virUnrefConnect
function is run. If this causes the last reference on the
virConnectPtr to be released, then virReleaseConnect can
be run, which in turns calls qemudClose. This function has
a call to virDomainEventStateDeregisterConn which is intended
to remove all callbacks associated with the virConnectPtr
instance. This will try to grab a lock on virDomainEventState
but this lock is already held. Deadlock ensues
Thread 1 (Thread 0x7fcbb526a840 (LWP 23185)):
Since each callback associated with a virConnectPtr holds a
reference on virConnectPtr, it is impossible for the qemudClose
method to be invoked while any callbacks are still registered.
Thus the call to virDomainEventStateDeregisterConn must in fact
be a no-op. Thus it is possible to just remove all trace of
virDomainEventStateDeregisterConn and avoid the deadlock.
* src/conf/domain_event.c, src/conf/domain_event.h,
src/libvirt_private.syms: Delete virDomainEventStateDeregisterConn
* src/libxl/libxl_driver.c, src/lxc/lxc_driver.c,
src/qemu/qemu_driver.c, src/uml/uml_driver.c: Remove
calls to virDomainEventStateDeregisterConn
This involves setting the cpuacct cgroup to a per-vcpu granularity,
as well as summing the each vcpu accounting into a common array.
Now that we are reading more than one cgroup file, we double-check
that cpus weren't hot-plugged between reads to invalidate our
summing.
Signed-off-by: Eric Blake <eblake@redhat.com>
To allow the security drivers to apply different configuration
information per hypervisor, pass the virtualization driver name
into the security manager constructor.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Thanks to this new option we are now able to use modern CPU models (such
as Westmere) defined in external configuration file.
The qemu-1.1{,-device} data files for qemuhelptest are filled in with
qemu-1.1-rc2 output for now. I will update those files with real
qemu-1.1 output once it is released.
As defined in:
http://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html
This offers a number of advantages:
* Allows sharing a home directory between different machines, or
sessions (eg. using NFS)
* Cleanly separates cache, runtime (eg. sockets), or app data from
user settings
* Supports performing smart or selective migration of settings
between different OS versions
* Supports reseting settings without breaking things
* Makes it possible to clear cache data to make room when the disk
is filling up
* Allows us to write a robust and efficient backup solution
* Allows an admin flexibility to change where data and settings are stored
* Dramatically reduces the complexity and incoherence of the
system for administrators
After a cpu hotplug the qemu driver did not refresh information about
virtual processors used by qemu and their corresponding threads. This
patch forces a re-detection as is done on start of QEMU.
This ensures that correct information is reported by the
virDomainGetVcpus API and "virsh vcpuinfo".
A failure to obtain the thread<->vcpu mapping is treated non-fatal and
the mapping is not updated in a case of failure as not all versions of
QEMU report this in the info cpus command.
This patch changes a switch statement into ifs when handling live vs.
configuration modifications getting rid of redundant code in case when
both live and persistent configuration gets changed.
It turns out that when cgroups are enabled, the use of a block device
for a snapshot target was failing with EPERM due to libvirt failing
to add the block device to the cgroup whitelist. See also
https://bugzilla.redhat.com/show_bug.cgi?id=810200
* src/qemu/qemu_driver.c
(qemuDomainSnapshotCreateSingleDiskActive)
(qemuDomainSnapshotUndoSingleDiskActive): Account for cgroup.
(qemuDomainSnapshotCreateDiskActive): Update caller.
When we added the default USB controller into domain XML, we efficiently
broke migration to older versions of libvirt that didn't support USB
controllers at all (0.9.4 and earlier) even for domains that don't use
anything that the older libvirt can't provide. We still want to present
the default USB controller in any XML seen by a user/app but we can
safely remove it from the domain XML used during migration. If we are
migrating to a new enough libvirt, it will add the controller XML back,
while older libvirt won't be confused with it although it will still
tell qemu to create the controller.
Similar approach can be used in the future whenever we find out we
always enabled some kind of device without properly advertising it in
domain XML.
Commit 4c82f09e added a capability check for qemu per-device io
throttling, but only applied it to domain startup. As mentioned
in the previous commit (98cec05), the user can still get an 'internal
error' message during a hotplug attempt, when the monitor command
doesn't exist. It is confusing to allow tuning on inactive domains
only to then be rejected when starting the domain.
* src/qemu/qemu_driver.c (qemuDomainSetBlockIoTune): Reject
offline tuning if online can't match it.
If you have a qemu build that lacks the blockio tune monitor command,
then this command:
$ virsh blkdeviotune rhel6u2 hda --total_bytes_sec 1000
error: Unable to change block I/O throttle
error: internal error Unexpected error
fails as expected (well, the error message is lousy), but the next
dumpxml shows that the domain was modified anyway. Worse, that means
if you save the domain then restore it, the restore will likely fail
due to throttling being unsupported, even though no throttling should
even be active because the monitor command failed in the first place.
* src/qemu/qemu_driver.c (qemuDomainSetBlockIoTune): Check for
error before making modification permanent.
Error: RESOURCE_LEAK:
/libvirt/src/qemu/qemu_driver.c:6968:
alloc_fn: Calling allocation function "calloc".
/libvirt/src/qemu/qemu_driver.c:6968:
var_assign: Assigning: "nodeset" = storage returned from "calloc(1UL, 1UL)".
/libvirt/src/qemu/qemu_driver.c:6977:
noescape: Variable "nodeset" is not freed or pointed-to in function "virTypedParameterAssign".
/libvirt/src/qemu/qemu_driver.c:6997:
leaked_storage: Variable "nodeset" going out of scope leaks the storage it points to.
When libvirtd is started, we create "libvirt/qemu" directories under
hugetlbfs mount point. Only the "qemu" subdirectory is chowned to qemu
user and "libvirt" remains owned by root. If umask was too restrictive
when libvirtd started, qemu user may lose access to "qemu"
subdirectory. Let's explicitly grant search permissions to "libvirt"
directory for all users.
With RHEL 6.2, virDomainBlockPull(dom, dev, bandwidth, 0) has a race
with non-zero bandwidth: there is a window between the block_stream
and block_job_set_speed monitor commands where an unlimited amount
of data was let through, defeating the point of a throttle.
This race was first identified in commit a9d3495e, and libvirt was
able to reduce the size of the window for that race. In the meantime,
the qemu developers decided to fix things properly; per this message:
https://lists.gnu.org/archive/html/qemu-devel/2012-04/msg03793.html
the fix will be in qemu 1.1, and changes block-job-set-speed to use
a different parameter name, as well as adding a new optional parameter
to block-stream, which eliminates the race altogether.
Since our documentation already mentioned that we can refuse a non-zero
bandwidth for some hypervisors, I think the best solution is to do
just that for RHEL 6.2 qemu, so that the race is obvious to the user
(anyone using stock RHEL 6.2 binaries won't have this patch, and anyone
building their own libvirt with this patch for RHEL can also rebuild
qemu to get the modern semantics, so it is no real loss in behavior).
Meanwhile the code must be fixed to honor actual qemu 1.1 naming.
Rename the parameter to 'modern', since the naming difference now
covers more than just 'async' block-job-cancel. And while at it,
fix an unchecked integer overflow.
* src/qemu/qemu_monitor.h (enum BLOCK_JOB_CMD): Drop unused value,
rename enum to match conventions.
* src/qemu/qemu_monitor.c (qemuMonitorBlockJob): Reflect enum rename.
* src/qemu_qemu_monitor_json.h (qemuMonitorJSONBlockJob): Likewise.
* src/qemu/qemu_monitor_json.c (qemuMonitorJSONBlockJob): Likewise,
and support difference between RHEL 6.2 and qemu 1.1 block pull.
* src/qemu/qemu_driver.c (qemuDomainBlockJobImpl): Reject
bandwidth during pull with too-old qemu.
* src/libvirt.c (virDomainBlockPull, virDomainBlockRebase):
Document this.
QEMU binary is called several times when we probe different kinds of
capabilities the binary supports. This patch introduces new common
helper so that all probes use a consistent way of invoking qemu.
https://bugzilla.redhat.com/show_bug.cgi?id=816662 pointed out
that attempting 'virsh blockpull' on an offline domain gave a
misleading error message about qemu lacking support for the
operation, even when qemu was specifically updated to support it.
The real problem is that we have several capabilities that are
only determined when starting a domain, and therefore are still
clear when first working with an inactive domain (namely, any
capability set by qemuMonitorJSONCheckCommands).
While this patch was able to hoist an existing check in one of the
three culprits, it had to add redundant checks in the other two
places (because you always have to check for an active domain after
obtaining a VM job lock, but the capability bits were being checked
prior to obtaining the job lock).
Someday it would be nice to patch libvirt to cache the set of
capabilities per qemu binary (as determined by inode and timestamp),
rather than re-probing the binary every time a domain is started,
and to teach the cache how to query the monitor during the one
time the probe is made rather than having to wait until a guest
is started; then, a capability probe would succeed even for offline
guests because it just refers to the cache, and the single check for
an active domain after grabbing the job lock would be sufficient.
But since that will involve a lot more coding, I'm happy to go
with this simpler solution for an immediate solution.
* src/qemu/qemu_driver.c (qemuDomainPMSuspendForDuration)
(qemuDomainSnapshotCreateXML, qemuDomainBlockJobImpl): Check for
offline state before checking an online-only cap.
Most of our errors complaining about an inability to support a
particular action due to qemu limitations used CONFIG_UNSUPPORTED,
but we had a few outliers. Reported by Jiri Denemark.
* src/qemu/qemu_command.c (qemuBuildDriveDevStr): Prefer
CONFIG_UNSUPPORTED.
* src/qemu/qemu_driver.c (qemuDomainReboot)
(qemuDomainBlockJobImpl): Likewise.
* src/qemu/qemu_hotplug.c (qemuDomainAttachPciControllerDevice):
Likewise.
* src/qemu/qemu_monitor.c (qemuMonitorTransaction)
(qemuMonitorBlockJob, qemuMonitorSystemWakeup): Likewise.
Currently, we have 3 boolean arguments we have to pass
to qemuProcessStart(). As libvirt grows it is harder and harder
to remember them and their position. Therefore we should
switch to flags instead.
If dynamic_ownership is off and we are creating a file on NFS
we force chown. This will fail as chown/chmod are not supported
on NFS. However, with no dynamic_ownership we are not required
to do any chown.
In my testing, I was able to provoke an odd block pull failure:
$ virsh blockpull dom vda --bandwidth 10000
error: Requested operation is not valid: No active operation on device: drive-virtio-disk0
merely by using gdb to artifically wait to do the block job set speed
until after the pull had already finished. But in reality, that should
be a success, since the pull finished before we had a chance to set
speed. Furthermore, using a double job lock is not only annoying, but
a bug in itself - if you do parallel virDomainBlockRebase, and hit
the race window just right, the first call grabs the VM job to start
a fast block job, then the second call grabs the VM job to start
a long-running job with unspecified speed, then the first call finally
regrabs the VM job and sets the speed, which ends up running the
second job under the speed from the first call. By consolidating
things into a single job, we avoid opening that race, as well as reduce
the time between starting the job and changing the speed, for less
likelihood of the speed change happening after block job completion
in the first place.
* src/qemu/qemu_monitor.h (BLOCK_JOB_CMD): Add new mode.
* src/qemu/qemu_driver.c (qemuDomainBlockRebase): Move secondary
job call...
(qemuDomainBlockJobImpl): ...here, for fewer locks.
* src/qemu/qemu_monitor_json.c (qemuMonitorJSONBlockJob): Change
return value on new internal mode.
Without the VIR_DOMAIN_BLOCK_JOB_ABORT_ASYNC flag, libvirt will internally
poll using qemu's "query-block-jobs" API and will not return until the
operation has been completed. API users are advised that this operation
is unbounded and further interaction with the domain during this period
may block. Future patches may refactor things to allow other queries in
parallel with this polling. For older qemu, we synthesize the cancellation
event, since qemu won't generate it.
The choice of polling duration copies from the code in qemu_migration.c.
Signed-off-by: Adam Litke <agl@us.ibm.com>
Cc: Stefan Hajnoczi <stefanha@gmail.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
RHEL 6.2 was released with an early version of block jobs, which only
worked on the qed file format, where the commands were spelled with
underscore (contrary to QMP style), and where 'block_job_cancel' was
synchronous and did not trigger an event.
The upcoming qemu 1.1 release has fixed these short-comings [1][2]:
the commands now work on multiple file types, are spelled with dash,
and 'block-job-cancel' is asynchronous and emits an event upon conclusion.
[1]qemu commit 370521a1d6f5537ea7271c119f3fbb7b0fa57063
[2]https://lists.gnu.org/archive/html/qemu-devel/2012-04/msg01248.html
This patch recognizes the new spellings, and fixes virDomainBlockRebase
to give a graceful error when talking to a too-old qemu on a partial
rebase attempt. Fixes for the new semantics will come later. This
patch also removes a bogus ATTRIBUTE_NONNULL mistakenly added in
commit 10ec36e2.
* src/qemu/qemu_capabilities.h (QEMU_CAPS_BLOCKJOB_SYNC)
(QEMU_CAPS_BLOCKJOB_ASYNC): New bits.
* src/qemu/qemu_capabilities.c (qemuCaps): Name them.
* src/qemu/qemu_monitor_json.c (qemuMonitorJSONCheckCommands): Set
them.
(qemuMonitorJSONBlockJob): Manage both command names.
(qemuMonitorJSONDiskSnapshot): Minor formatting fix.
* src/qemu/qemu_monitor.h (qemuMonitorBlockJob): Alter signature.
* src/qemu/qemu_monitor_json.h (qemuMonitorJSONBlockJob): Likewise.
* src/qemu/qemu_monitor.c (qemuMonitorBlockJob): Pass through
capability bit.
* src/qemu/qemu_driver.c (qemuDomainBlockJobImpl): Update callers.
The new safe console handling introduced a possibility to deadlock the
qemu driver when a new console connection forcibly disconnects a
previous console stream that belongs to an already closed connection.
The virStreamFree function calls subsequently a the virReleaseConnect
function that tries to lock the driver while discarding the connection,
but the driver was already locked in qemuDomainOpenConsole.
Backtrace of the deadlocked thread:
0 0x00007f66e5aa7f14 in __lll_lock_wait () from /lib64/libpthread.so.0
1 0x00007f66e5aa3411 in _L_lock_500 () from /lib64/libpthread.so.0
2 0x00007f66e5aa322a in pthread_mutex_lock () from/lib64/libpthread.so.0
3 0x0000000000462bbd in qemudClose ()
4 0x00007f66e6e178eb in virReleaseConnect () from/usr/lib64/libvirt.so.0
5 0x00007f66e6e19c8c in virUnrefStream () from /usr/lib64/libvirt.so.0
6 0x00007f66e6e3d1de in virStreamFree () from /usr/lib64/libvirt.so.0
7 0x00007f66e6e09a5d in virConsoleHashEntryFree () from/usr/lib64/libvirt.so.0
8 0x00007f66e6db7282 in virHashRemoveEntry () from/usr/lib64/libvirt.so.0
9 0x00007f66e6e09c4e in virConsoleOpen () from /usr/lib64/libvirt.so.0
10 0x00000000004526e9 in qemuDomainOpenConsole ()
11 0x00007f66e6e421f1 in virDomainOpenConsole () from/usr/lib64/libvirt.so.0
12 0x00000000004361e4 in remoteDispatchDomainOpenConsoleHelper ()
13 0x00007f66e6e80375 in virNetServerProgramDispatch () from/usr/lib64/libvirt.so.0
14 0x00007f66e6e7ae11 in virNetServerHandleJob () from/usr/lib64/libvirt.so.0
15 0x00007f66e6da897d in virThreadPoolWorker () from/usr/lib64/libvirt.so.0
16 0x00007f66e6da7ff6 in virThreadHelper () from/usr/lib64/libvirt.so.0
17 0x00007f66e5aa0c5c in start_thread () from /lib64/libpthread.so.0
18 0x00007f66e57e7fcd in clone () from /lib64/libc.so.6
* src/qemu/qemu_driver.c: qemuDomainOpenConsole()
-- unlock the qemu driver right after acquiring the domain
object
Leak introduced in commit 0436d32. If we allocate an actions array,
but fail early enough to never consume it with the qemu monitor
transaction call, we leaked memory.
But our semantics of making the transaction command free the caller's
memory is awkward; avoiding the memory leak requires making every
intermediate function in the call chain check for error. It is much
easier to fix things so that the function that allocates also frees,
while the call chain leaves the caller's data intact. To do that,
I had to hack our JSON data structure to make it easy to protect a
portion of an arbitrary JSON tree from being freed.
* src/util/json.h (virJSONType): Name the enum.
(_virJSONValue): New field.
* src/util/json.c (virJSONValueFree): Use it to protect a portion
of an array.
* src/qemu/qemu_monitor_json.c (qemuMonitorJSONTransaction): Avoid
freeing caller's data.
* src/qemu/qemu_driver.c (qemuDomainSnapshotCreateDiskActive):
Free actions array on failure.
We can tell qemuDomainSnapshotFSThaw if we want it to report errors or
not. However, if we don't want to and an error has been already set by
previous qemuReportError() we must keep copy of that error not just a
pointer to it. Otherwise, it get overwritten if FSThaw reports an error.
