Commit Graph

714 Commits

Author SHA1 Message Date
Daniel P. Berrange
3e12ec4a1e qemu: use virtlogd for character device log files
If use of virtlogd is enabled, then use it for backing the
character device log files too. This avoids the possibility
of a guest denial of service by writing too much data to
the log file.
2016-03-10 15:41:52 +00:00
Jiri Denemark
315808e99e qemu: Don't explicitly stop CPUs after migration
With a very old QEMU which doesn't support events we need to explicitly
call qemuMigrationSetOffline at the end of migration to update our
internal state. On the other hand, if we talk to QEMU using QMP, we
should just wait for the STOP event and let the event handler update the
state and trigger a libvirt event.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
2016-03-08 16:25:59 +01:00
Alexander Burluka
ef1fa55e46 Implement qemuSetupGlobalCpuCgroup
This functions setups per-domain cpu bandwidth parameters

Signed-off-by: Alexander Burluka <aburluka@virtuozzo.com>
2016-03-01 14:30:11 +00:00
Henning Schild
ff16bde100 qemu_cgroup: use virCgroupAddTask instead of virCgroupMoveTask
qemuProcessSetupEmulator runs at a point in time where there is only
the qemu main thread. Use virCgroupAddTask to put just that one task
into the emulator cgroup. That patch makes virCgroupMoveTask and
virCgroupAddTaskStrController obsolete.

Signed-off-by: Henning Schild <henning.schild@siemens.com>
2016-03-01 14:07:27 +00:00
Henning Schild
8e21e8d110 qemu_cgroup: put qemu right into emulator sub-cgroup
Move qemuProcessSetupEmulator up under qemuSetupCgroup. That way
we move the one main thread right into the emulator cgroup, instead
of moving multiple threads later on. And we do not actually want any
threads running in the parent cgroups (cpu cpuacct cpuset).

Signed-off-by: Henning Schild <henning.schild@siemens.com>
2016-03-01 14:07:27 +00:00
Peter Krempa
a06ef20782 qemu: process: Move emulator thread setting code into one function
Similarly to the refactors to iothreads and vcpus, move the code that
initializes the emulator thread settings into single function.
2016-03-01 14:07:27 +00:00
Pavel Hrdina
b4a5fd95f7 qemu: introduce vram64 attribute for QXL video device
This attribute is used to extend secondary PCI bar and expose it to the
guest as 64bit memory.  It works like this: attribute vram is there to
set size of secondary PCI bar and guest sees it as 32bit memory,
attribute vram64 can extend this secondary PCI bar.  If both attributes
are used, guest sees two memory bars, both address the same memory, with
the difference that the 32bit bar can address only the first part of the
whole memory.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1260749

Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
2016-03-01 14:17:09 +01:00
Martin Kletzander
a89f05ba8d qemu: Shorten per-domain directory names
Per-domain directories were introduced in order to be able to
completely separate security labels for each domain (commit
f1f68ca334).  However when the domain
name is long (let's say a ridiculous 110 characters), we cannot
connect to the monitor socket because on length of UNIX socket address
is limited.  In order to get around this, let's shorten it in similar
fashion and in order to avoid conflicts, throw in an ID there as well.
Also save that into the status XML and load the old status XMLs
properly (to clean up after older domains).  That way we can change it
in the future.

The shortening can be seen in qemuxml2argv tests, for example in the
hugepages-pages2 case.

Signed-off-by: Martin Kletzander <mkletzan@redhat.com>
2016-03-01 07:15:29 +01:00
Pavel Hrdina
85a687c6b2 qemu_process: mark auto-generated spice ports as reserved
In case you will specify graphics like this:

<graphics type='spice' port='-1'/>

or

<graphics type='spice' port='-1' tlsPort='6000'/>

libvirt will automatically add autoport='no'.  This leads to an issue
that in qemuProcessStop() we don't release that port because we are
releasing both port if autoport=yes or only port marked as reserved.

If autoport=no but we request to generate port via '-1' we need to mark
that port as reserved in order to release it.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1299696

Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
2016-02-22 14:34:45 +01:00
Jiri Denemark
81f50cb92d qemu: Avoid calling qemuProcessStop without a job
Calling qemuProcessStop without a job opens a way to race conditions
with qemuDomainObjExitMonitor called in another thread. A real world
example of such a race condition:

  - migration thread (A) calls qemuMigrationWaitForSpice
  - another thread (B) starts processing qemuDomainAbortJob API
  - thread B signals thread A via qemuDomainObjAbortAsyncJob
  - thread B enters monitor (qemuDomainObjEnterMonitor)
  - thread B calls qemuMonitorSend
  - thread A awakens and calls qemuProcessStop
  - thread A calls qemuMonitorClose and sets priv->mon to NULL
  - thread B calls qemuDomainObjExitMonitor with priv->mon == NULL
  => monitor stays ref'ed and locked

Depending on how lucky we are, the race may result in a memory leak or
it can even deadlock libvirtd's event loop if it tries to lock the
monitor to process an event received before qemuMonitorClose was called.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
2016-02-19 15:41:57 +01:00
Jiri Denemark
6f08cbb82b qemu: Simplify error handling in qemuProcessReconnect
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
2016-02-19 15:41:57 +01:00
Jiri Denemark
8c9ff9960b qemu: Process monitor EOF in a job
Stopping a domain without a job risks a race condition with another
thread which started a job a which does not expect anyone else to be
messing around with the same domain object.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
2016-02-19 15:41:57 +01:00
Jiri Denemark
4d0c535a36 qemu: Introduce qemuProcessBeginStopJob
When destroying a domain we need to make sure we will be able to start a
job no matter what other operations are running or even stuck in a job.
This is done by killing the domain before starting the destroy job.

Let's introduce qemuProcessBeginStopJob which combines killing a domain
and starting a job in a single API which can be called everywhere we
need a job to stop a domain.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
2016-02-19 15:41:57 +01:00
Jiri Denemark
b7a948be01 qemu: Pass async job to qemuProcessInit
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
2016-02-19 15:41:57 +01:00
John Ferlan
de71e0e500 qemu: Move qemuAssign*Alias* API's into their own module
Create a new module qemu_alias.c to handle the qemuAssign*Alias* APIs
and the qemuDomainDeviceAliasIndex
2016-02-16 11:07:48 -05:00
John Ferlan
aba930af15 qemu: Move qemuNetworkPrepareDevices
Move function to qemu_process.c, rename to qemuProcessNetworkPrepareDevices
and make it static.

Signed-off-by: John Ferlan <jferlan@redhat.com>
2016-02-16 11:07:48 -05:00
John Ferlan
177db48734 qemu: Move qemuDomain*Address* functions
Create new modules qemu_domain_address.c and qemu_domain_address.h to
contain all the new functions and header data. Additionally move any
supporting static functions.

Make qemuDomainSupportsPCI non static.

Also, move and rename the following:

qemuSetSCSIControllerModel to qemuDomainSetSCSIControllerModel
qemuCollectPCIAddress to qemuDomainCollectPCIAddress
qemuValidateDevicePCISlotsPIIX3 to qemuDomainValidateDevicePCISlotsPIIX3
qemuAssignDevicePCISlots to qemuDomainAssignDevicePCISlots

Signed-off-by: John Ferlan <jferlan@redhat.com>
2016-02-16 11:07:47 -05:00
Michal Privoznik
88ed9d771e qemu: Connect to guest agent iff needed
https://bugzilla.redhat.com/show_bug.cgi?id=1293351

Since we already have virtio channel events, we know when guest
agent within guest has (dis-)connected. Instead of us blindly
connecting to a socket that no one is listening to, we can just
follow what qemu-ga does. This has a nice benefit that we don't
need to 'guest-ping' the agent just to timeout and find out
nobody is listening.

The way that this commit is implemented:
- don't connect in qemuProcessLaunch directly, defer that to event
  callback (which already follows the agent) -
  processSerialChangedEvent
- after migration is settled, before we resume vCPUs, ask qemu
  whether somebody is listening on the socket and if so, connect
  to it.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
2016-02-11 06:52:50 +01:00
Peter Krempa
1dcc4c7ffd qemu: iothread: Aggregate code to set IOThread tuning
Rather than iterating 3 times for various settings this function
aggregates all the code into single place. One of the other advantages
is that it can then be reused for properly setting IOThread info on
hotplug.
2016-02-08 17:05:00 +01:00
Peter Krempa
56971667ee qemu: vcpu: Aggregate code to set vCPU tuning
Rather than iterating 3 times for various settings this function
aggregates all the code into single place. One of the other advantages
is that it can then be reused for properly setting vCPU info on hotplug.

With this approach autoCpuset is also used when setting the process
affinity rather than just via cgroups.
2016-02-08 17:05:00 +01:00
Peter Krempa
6dfb4507f5 conf: Fix how iothread scheduler info is stored
Similarly to previous commit change the way how iothread scheduler info
is stored and clean up a lot of unnecessary code.
2016-02-08 09:51:34 +01:00
Peter Krempa
99c5fe0e7c conf: Don't store vcpusched orthogonally to other vcpu info
Due to bad design the vcpu sched element is orthogonal to the way how
the data belongs to the corresponding objects. Now that vcpus are a
struct that allow to store other info too, let's convert the data to the
sane structure.

The helpers for the conversion are made universal so that they can be
reused for iothreads too.

This patch also resolves https://bugzilla.redhat.com/show_bug.cgi?id=1235180
since with the correct storage approach you can't have dangling data.
2016-02-08 09:51:34 +01:00
Peter Krempa
d2a6fc79e3 conf: Store cpu pinning data in def->vcpus
Now with the new struct the data can be stored in a much saner place.
2016-02-08 09:51:34 +01:00
Peter Krempa
856f254eef conf: Don't copy def->cpumask into cpu pinning info
This step can be omitted, so that drivers can decide what to do when the
user requests to use default vcpu pinning.
2016-02-08 09:51:34 +01:00
Peter Krempa
c07bc2cc7d qemu: process: Extract pre-start checks into a function
When starting a qemu process there are certain checks done to ensure
that the configuration makes sense. Extract them into a separate
function so that they can be reused in the test code.
2016-02-08 09:19:48 +01:00
Peter Krempa
c3e170647e qemu: process: Reorder operations on early VM startup
Retrieval of the driver capabilities as well as emulator capabilities
does not require the complete qemuProcessStop to be executed on
failure.
2016-02-08 09:08:38 +01:00
Martin Kletzander
c3bd0019c0 systemd: Modernize machine naming
So, systemd-machined has this philosophy that machine names are like
hostnames and hence should follow the same rules.  But we always allowed
international characters in domain names.  Thus we need to modify the
machine name we are passing to systemd.

In order to change some machine names that we will be passing to systemd,
we also need to call TerminateMachine at the end of a lifetime of a
domain.  Even for domains that were started with older libvirt.  That
can be achieved thanks to virSystemdGetMachineNameByPID().  And because
we can change machine names, we can get rid of the inconsistent and
pointless escaping of domain names when creating machine names.

So this patch modifies the naming in the following way.  It creates the
name as <drivername>-<id>-<name> where invalid hostname characters are
stripped out of the name and if the resulting name is longer, it
truncates it to 64 characters.  That way we can start domains we
couldn't start before.  Well, at least on systemd.

To make it work all together, the machineName (which is needed only with
systemd) is saved in domain's private data.  That way the generation is
moved to the driver and we don't need to pass various unnecessary
arguments to cgroup functions.

The only thing this complicates a bit is the scope generation when
validating a cgroup where we must check both old and new naming, so a
slight modification was needed there.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1282846

Signed-off-by: Martin Kletzander <mkletzan@redhat.com>
2016-02-05 16:11:50 +01:00
Daniel P. Berrange
1036ddadb2 conf: add caps to virDomainObjFormat/SaveStatus
The virDomainObjFormat and virDomainSaveStatus methods
both call into virDomainDefFormat, so should be providing
a non-NULL virCapsPtr instance.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2016-02-05 10:57:08 +00:00
Joao Martins
cd57b7c742 conf: add caps to virDomainSaveConfig
virDomainSaveConfig calls virDomainDefFormat which was setting the caps
to NULL, thus keeping the old behaviour (i.e. not looking at
netprefix). This patch adds the virCapsPtr to the function and allows
the configuration to be saved and skipping interface names that were
registered with virCapabilitiesSetNetPrefix().

Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
2016-02-04 12:38:27 +00:00
Peter Krempa
e97d1d20b1 qemu: Move and rename qemuProcessDetectVcpuPIDs to qemuDomainDetectVcpuPids
Future patches will tweak and reuse the function in different places so
move it separately first.
2016-02-03 13:10:04 +01:00
Peter Krempa
d773b57d22 qemu: don't iterate vcpus using priv->nvcpupids in qemuProcessSetSchedParams
This should be the last offender.
2016-01-28 09:58:24 +01:00
Laine Stump
370608b4c7 util: keep/use a bitmap of in-use macvtap devices
This patch creates two bitmaps, one for macvlan device names and one
for macvtap. The bitmap position is used to indicate that libvirt is
currently using a device with the name macvtap%d/macvlan%d, where %d
is the position in the bitmap. When requested to create a new
macvtap/macvlan device, libvirt will now look for the first clear bit
in the appropriate bitmap and derive the device name from that rather
than just starting at 0 and counting up until one works.

When libvirtd is restarted, the qemu driver code that reattaches to
active domains calls the appropriate function to "re-reserve" the
device names as it is scanning the status of running domains.

Note that it may seem strange that the retry counter now starts at
8191 instead of 5. This is because we now don't do a "pre-check" for
the existence of a device once we've reserved it in the bitmap - we
move straight to creating it; although very unlikely, it's possible
that someone has a running system where they have a large number of
network devices *created outside libvirt* named "macvtap%d" or
"macvlan%d" - such a setup would still allow creating more devices
with the old code, while a low retry max in the new code would cause a
failure. Since the objective of the retry max is just to prevent an
infinite loop, and it's highly unlikely to do more than 1 iteration
anyway, having a high max is a reasonable concession in order to
prevent lots of new failures.
2016-01-26 12:20:04 -05:00
Peter Krempa
b3c91b8a50 qemu: process: Disallow VMs with 0 vcpus
Counterintuitively the user would end up with a VM with maximum number
of vCPUs available.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1290324
2016-01-25 17:45:09 +01:00
Peter Krempa
adca15cf15 qemu: process: refactor and rename qemuValidateCpuMax to qemuValidateCpuCount
Next patch will add minimum checking, so use a more generic name.
Refactor return values to the commonly used semantics.
2016-01-25 17:45:09 +01:00
Jiri Denemark
56635345ad qemu: Add support for migration iteration event
The corresponding event in QEMU is called MIGRATION_PASS.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
2016-01-21 16:36:08 +01:00
Michal Privoznik
105b51f42e qemuProcessReadLog: Fix memmove arguments
So I can observe this crasher that with freshly started daemon
(and virtlogd enabled) I am trying to startup a domain that
immediately dies (because it's said to use huge pages but I
haven't allocated a single one in the pool). Hardly reproducible
with -O0 or under valgrind. But I just got lucky:

==20469== Invalid write of size 8
==20469==    at 0x4C2E99B: memcpy@GLIBC_2.2.5 (in /usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so)
==20469==    by 0x217EDD07: qemuProcessReadLog (qemu_process.c:1670)
==20469==    by 0x217EDE1D: qemuProcessReportLogError (qemu_process.c:1696)
==20469==    by 0x217EE8C1: qemuProcessWaitForMonitor (qemu_process.c:1957)
==20469==    by 0x217F6636: qemuProcessLaunch (qemu_process.c:4955)
==20469==    by 0x217F71A4: qemuProcessStart (qemu_process.c:5152)
==20469==    by 0x21846582: qemuDomainObjStart (qemu_driver.c:7396)
==20469==    by 0x218467DE: qemuDomainCreateWithFlags (qemu_driver.c:7450)
==20469==    by 0x21846845: qemuDomainCreate (qemu_driver.c:7468)
==20469==    by 0x5611CD0: virDomainCreate (libvirt-domain.c:6753)
==20469==    by 0x125D9A: remoteDispatchDomainCreate (remote_dispatch.h:3613)
==20469==    by 0x125CB7: remoteDispatchDomainCreateHelper (remote_dispatch.h:3589)
==20469==  Address 0x27a52ad0 is 0 bytes after a block of size 5,584 alloc'd
==20469==    at 0x4C29F80: malloc (in /usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so)
==20469==    by 0x9B8D1DB: xdr_string (in /lib64/libc-2.21.so)
==20469==    by 0x563B39C: xdr_virLogManagerProtocolNonNullString (log_protocol.c:24)
==20469==    by 0x563B6B7: xdr_virLogManagerProtocolDomainReadLogFileRet (log_protocol.c:123)
==20469==    by 0x164B34: virNetMessageDecodePayload (virnetmessage.c:407)
==20469==    by 0x5682360: virNetClientProgramCall (virnetclientprogram.c:379)
==20469==    by 0x563B30E: virLogManagerDomainReadLogFile (log_manager.c:272)
==20469==    by 0x217CD613: qemuDomainLogContextRead (qemu_domain.c:2485)
==20469==    by 0x217EDC76: qemuProcessReadLog (qemu_process.c:1660)
==20469==    by 0x217EDE1D: qemuProcessReportLogError (qemu_process.c:1696)
==20469==    by 0x217EE8C1: qemuProcessWaitForMonitor (qemu_process.c:1957)
==20469==    by 0x217F6636: qemuProcessLaunch (qemu_process.c:4955)

This points to memmove() in qemuProcessReadLog(). Imagine we just
read the following string from qemu:

"abc\n2016-01-18T09:40:44.022744Z qemu-system-x86_64: Error\n"

After the first pass of the while() loop in the
qemuProcessReadLog() (in which we have taken the false branch in
the if) @buf still points to the beginning of the string,
@filter_next points to the beginning of the second line.  So we
start second iteration because there is yet another newline
character at the end. In this iteration @eol points to it
actually. Now, the control gets inside true branch of if(). Just
to remind you:

got = 58
filter_next = buf + 5,
eol = buf + 58.

Therefore skip = 54 which is correct. The message we want to skip
is 54 bytes long. However:

memmove(filter_next, eol + 1, (got - skip) +1);

which is

memmove(filter_next, eol + 1, 5)

is obviously wrong as there is only one byte we can access, not 5!

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
2016-01-18 17:14:16 +01:00
John Ferlan
f8f6907284 Revert "qemu: do not put a task into machine cgroup"
This reverts commit a41c00b472.

After much testing and upstream discussion this has been deemed to be
the incorrect operation since it means we no longer have any guarantee
about which resource controllers the QEMU processes in general are in.
2016-01-14 10:56:53 -05:00
Michal Privoznik
e988ba94aa qemuProcessCleanupChardevDevice: Don't unlink NULL paths
So, you try to start a domain, but before we even get to the part
where chardev part of qemu command line is generated (and
possibly missing path to unix sockets is made up) an error occurs
which results in calling qemuProcessStop. This will then try to
clean up the mess and possibly ends up calling unlink(NULL).

==8085== Thread 3:
==8085== Syscall param unlink(pathname) points to unaddressable byte(s)
==8085==    at 0xA85EA57: unlink (in /lib64/libc-2.21.so)
==8085==    by 0x213D3C24: qemuProcessCleanupChardevDevice (qemu_process.c:2866)
==8085==    by 0x558D6B1: virDomainChrDefForeach (domain_conf.c:22924)
==8085==    by 0x213DA9AE: qemuProcessStop (qemu_process.c:5326)
==8085==    by 0x213DA2F2: qemuProcessStart (qemu_process.c:5190)
==8085==    by 0x2142957F: qemuDomainObjStart (qemu_driver.c:7396)
==8085==    by 0x214297DB: qemuDomainCreateWithFlags (qemu_driver.c:7450)
==8085==    by 0x21429842: qemuDomainCreate (qemu_driver.c:7468)
==8085==    by 0x5611B95: virDomainCreate (libvirt-domain.c:6753)
==8085==    by 0x125D9A: remoteDispatchDomainCreate (remote_dispatch.h:3613)
==8085==    by 0x125CB7: remoteDispatchDomainCreateHelper (remote_dispatch.h:3589)
==8085==    by 0x568BF41: virNetServerProgramDispatchCall (virnetserverprogram.c:437)
==8085==  Address 0x0 is not stack'd, malloc'd or (recently) free'd
==8085==

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
2016-01-13 11:30:38 +01:00
Michal Privoznik
d5762cc034 qemu: change qemuFindAgentConfig return type
While this is no functional change, whole channel definition is
going to be needed very soon. Moreover, while touching this obey
const correctness rule in qemuAgentOpen() - so far it was passed
regular pointer to channel config even though the function is
expected to not change pointee at all. Pass const pointer
instead.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
2016-01-11 17:17:52 +01:00
Jiri Denemark
09bbd96239 qemu: Rename qemuMonitorMigrationStatus struct
The structure actually contains migration statistics rather than just
the status as the name suggests. Renaming it as
qemuMonitorMigrationStats removes the confusion.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
2016-01-08 18:18:58 +01:00
Jiri Denemark
f87668b70e qemu: Fix NBD migration with default listenAddress
My commit 674afcb09e moved computing the
default listen address from qemuMigrationPrepareAny to
qemuMigrationPrepareIncoming. However, I didn't notice listenAddress was
later passed to qemuMigrationStartNBDServer. Thus, it would be called
with the original value of listenAddress (NULL).

Let's add the updated listen address to qemuProcessIncomingDef and use
it when starting NBD servers.

Reported-by: Michael Chapman <mike@very.puzzling.org>
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
2016-01-08 10:39:20 +01:00
Martin Kletzander
68d4245d21 qemu: Search all nodes for shared memory access
In commit 686eb7a24f, the break was not considered part of the
condition, hence breaking after first node when searching.

Signed-off-by: Martin Kletzander <mkletzan@redhat.com>
2015-12-16 13:02:33 +01:00
Henning Schild
a41c00b472 qemu: do not put a task into machine cgroup
The machine cgroup is a superset, a parent to the emulator and vcpuX
cgroups. The parent cgroup should never have any tasks directly in it.
In fact the parent cpuset might contain way more cpus than the sum of
emulatorpin and vcpupins. So putting tasks in the superset will allow
them to run outside of <cputune>.

Signed-off-by: Henning Schild <henning.schild@siemens.com>
2015-12-14 15:48:05 -05:00
Martin Kletzander
686eb7a24f qemu: Warn when using vhost-user without shared memory
When user configures vhost-user interface and forgets to also configure
any shared memory, the search for the root cause of non-operational
interface might take unpleasantly long time.  Let's enhance user
experience by emitting a warning in the logs.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1266982

Signed-off-by: Martin Kletzander <mkletzan@redhat.com>
2015-12-14 08:54:19 +01:00
Peter Krempa
e6b36736a8 qemu: Add helper to retrieve vCPU pid
Instead of directly accessing the array add a helper to do this.
2015-12-09 14:57:12 +01:00
Peter Krempa
220a2d51de qemu: Replace checking for vcpu<->pid mapping availability with a helper
Add qemuDomainHasVCpuPids to do the checking and replace in place checks
with it.

We no longer need checking whether the thread contains fake data
(vcpupids[0] == vm->pid) as in b07f3d821d
and 65686e5a81 this was removed.
2015-12-09 14:57:12 +01:00
Peter Krempa
71c89ac9df conf: Replace read accesses to def->vcpus with accessor 2015-12-09 14:57:12 +01:00
Peter Krempa
d1dda68777 conf: Replace read access to def->maxvcpus with accessor
Finalize the refactor by adding the 'virDomainDefGetVCpusMax' getter and
reusing it accross libvirt.
2015-12-09 14:57:12 +01:00
Daniel P. Berrange
45c7b9e636 qemu: include hostname in QEMU log files
Often when debugging bug reports one is given a copy of the file
from /var/log/libvirt/qemu/$NAME.log along with other supporting
files. In a number of cases I've been given sets of files which
were from different machines. Including the hostname in the QEMU
log file will help identify when the bug reporter is providing
bad information.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2015-12-04 18:19:25 +00:00
Wang Yufei
fe51174f08 qemu_agent: fix deadlock in qemuProcessHandleAgentEOF
If VM A is shutdown a by qemu agent at appoximately the same time
an agent EOF of VM A happened, there's a chance that deadlock may occur:

qemuProcessHandleAgentEOF in main thread
A)  priv->agent = NULL; //A happened before B

    //deadlock when we get agent lock which's held by worker thread
    qemuAgentClose(agent);

qemuDomainObjExitAgent called by qemuDomainShutdownFlags in worker thread
B)  hasRefs = virObjectUnref(priv->agent); // priv->agent is NULL,
                                           // return false
    if (hasRefs)
        virObjectUnlock(priv->agent); //agent lock will not be released here

In order to resolve, during EOF close the agent first, then set priv->agent
to NULL to fix the deadlock.

This essentially reverts commit id '1020a504'. It's also of note that commit
id '362d0477' notes a possible/rare deadlock similar to what was seen in
the monitor in commit id '25f582e3'. However, it seems interceding changes
including commit id 'd960d06f' should remove the deadlock issue.

With this change, if EOF is called:

    Get VM lock
    Check if !priv->agent || priv->beingDestroyed, then unlock VM
    Call qemuAgentClose
    Unlock VM

When qemuAgentClose is called
    Get Agent lock
    If Agent->fd open, close it
    Unlock Agent
    Unref Agent

qemuDomainObjEnterAgent
    Enter with VM lock
    Get Agent lock
    Increase Agent refcnt
    Unlock VM

After running agent command, calling qemuDomainObjExitAgent
    Enter with Agent lock
    Unref Agent
    If not last reference, unlock Agent
    Get VM lock

If we were in the middle of an EnterAgent, call Agent command, and
ExitAgent sequence and the EOF code is triggered, then the EOF code
can get the VM lock, make it's checks against !priv->agent ||
priv->beingDestroyed, and call qemuAgentClose. The CloseAgent
would wait to get agent lock. The other thread then will eventually
call ExitAgent, release the Agent lock and unref the Agent. Once
ExitAgent releases the Agent lock, AgentClose will get the Agent
Agent lock, close the fd, unlock the agent, and unref the agent.
The final unref would cause deletion of the agent.

Signed-off-by: Wang Yufei <james.wangyufei@huawei.com>
Reviewed-by: Ren Guannan <renguannan@huawei.com>
2015-11-30 14:20:27 -05:00
Daniel P. Berrange
a48539c013 qemu: convert monitor to use qemuDomainLogContextPtr indirectly
Currently the QEMU monitor is given an FD to the logfile. This
won't work in the future with virtlogd, so it needs to use the
qemuDomainLogContextPtr instead, but it shouldn't directly
access that object either. So define a callback that the
monitor can use for reporting errors from the log file.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2015-11-26 14:30:15 +00:00
Daniel P. Berrange
b8c52c00e9 qemu: convert process stop/attach to use qemuDomainLogContextPtr
When the qemuProcessAttach/Stop methods write a marker into
the log file, they can use qemuDomainLogContextWrite to
write a formatted message.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2015-11-26 14:30:15 +00:00
Daniel P. Berrange
d4ee61c08a qemu: convert qemuLogOperation to take a qemuDomainLogContextPtr
Instead of writing directly to a log file descriptor, change
qemuLogOperation to use qemuDomainLogContextWrite().

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2015-11-26 14:30:15 +00:00
Daniel P. Berrange
3d4452a7a2 qemu: change qemuDomainTaint APIs to accept qemuDomainLogContextPtr
The qemuDomainTaint APIs currently expect to be passed a log file
descriptor. Change them to instead use a qemuDomainLogContextPtr
to hide the implementation details.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2015-11-26 14:30:15 +00:00
Daniel P. Berrange
486917501f qemu: convert log file creation to use qemuDomainLogContextPtr
Convert the places which create/open log files to use the new
qemuDomainLogContextPtr object instead.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2015-11-26 14:30:15 +00:00
Daniel P. Berrange
69b0992178 qemu: unify code for reporting errors from QEMU log files
There are two pretty similar functions qemuProcessReadLog and
qemuProcessReadChildErrors. Both read from the QEMU log file
and try to strip out libvirt messages. The latter then reports
an error, while the former lets the callers report an error.

Re-write qemuProcessReadLog so that it uses a single read
into a dynamically allocated buffer. Then introduce a new
qemuProcessReportLogError that calls qemuProcessReadLog
and reports an error.

Convert all callers to use qemuProcessReportLogError.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2015-11-26 14:30:15 +00:00
Jiri Denemark
0004ddf0f6 qemu: Introduce qemuProcessFinishStartup
Finishes starting a new domain launched by qemuProcessLaunch.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
2015-11-25 15:27:31 +01:00
Jiri Denemark
f618d662ca qemu: Introduce qemuProcessLaunch
Once qemuProcessInit was called, qemuProcessLaunch will launch a new
QEMU process with stopped virtual CPUs.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
2015-11-25 15:27:31 +01:00
Jiri Denemark
b5ffd224f1 qemu: Introduce qemuProcessInit
qemuProcessStart is going to be split in three parts: qemuProcessInit,
qemuProcessLaunch, and qemuProcessFinish so that migration Prepare phase
can insert additional code in the process. qemuProcessStart will be a
small wrapper for all other callers.

qemuProcessInit prepares the domain up to the point when priv->qemuCaps
is initialized.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
2015-11-25 15:27:31 +01:00
Ján Tomko
668a0fef42 qemu: pass the asyncJob to qemuProcessStartCPUs
Now that new domains are started inside a QEMU_ASYNC_JOB_START job,
we need to pass it down to qemuProcessStartCPUs too.

This removes the warning:
qemuDomainObjEnterMonitorInternal:1750 : This thread seems to be the
async job owner; entering monitor without asking for a nested job is
dangerous

Introduced by commit 04c721f, before that this code path was only
executed with QEMU_ASYNC_JOB_NONE.

(This code is not executed on migration, because qemuMigrationPrepareAny
 sets the VIR_QEMU_PROCESS_START_PAUSED flag.)
2015-11-24 13:34:56 +01:00
Jiri Denemark
2205d58b32 qemu: Close logfd when closing monitor
Remembering to call qemuMonitorSetDomainLog in the right paths before
calling qemuProcessStop is annoying and easy to forget. And I already
forgot to do so in commit v1.2.8-52-g0389060: logfd may be leaked if
QEMU process dies between Prepare and Finish migration phases.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
2015-11-19 09:41:23 +01:00
Jiri Denemark
6e92b4438b qemu: Do not infer flags from other qemuProcessStart arguments
Every caller setting migrateFrom already sets
VIR_QEMU_PROCESS_START_PAUSED flag anyway.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
2015-11-19 09:41:23 +01:00
Jiri Denemark
856612876d qemu: Introduce qemuProcessMakeDir
qemuProcessMakeDir is used for creating a per-domain directory in a
given parent directory.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
2015-11-19 09:41:23 +01:00
Jiri Denemark
65e6548e48 qemu: Separate balloon code from qemuProcessStart
qemuProcessStart is so big that any nontrivial code should be moved to
dedicated functions to make the code easier to read and maintain.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
2015-11-19 09:41:23 +01:00
Jiri Denemark
f78d070d68 qemu: Enter monitor within qemuProcessSetLinkStates
Move {Enter,Exit}Monitor calls inside qemuProcessSetLinkStates to
simplify qemuProcessStart.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
2015-11-19 09:41:23 +01:00
Jiri Denemark
dd79eb8b77 qemu: Separate raw IO code from qemuProcessStart
qemuProcessStart is so big that any nontrivial code should be moved to
dedicated functions to make the code easier to read and maintain.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
2015-11-19 09:41:23 +01:00
Jiri Denemark
fe422b673b qemu: Separate graphics handling code from qemuProcessStart
qemuProcessStart is so big that any nontrivial code should be moved to
dedicated functions to make the code easier to read and maintain.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
2015-11-19 09:41:23 +01:00
Jiri Denemark
8cff921571 qemu: Separate hook handling code from qemuProcessStart
qemuProcessStart is so big that any nontrivial code should be moved to
dedicated functions to make the code easier to read and maintain.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
2015-11-19 09:41:23 +01:00
Jiri Denemark
da863c2ad1 qemu: Rename stdin_{fd,path} in qemuProcessStart
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
2015-11-19 09:41:23 +01:00
Jiri Denemark
2c4ba8b4f3 qemu: Use -incoming defer for migrations
Traditionally, we pass incoming migration URI on QEMU command line,
which has some drawbacks. Depending on the URI QEMU may initialize its
migration state immediately without giving us a chance to set any
additional migration parameters (this applies mainly for fd: URIs). For
some URIs the monitor may be completely blocked from the beginning until
migration is finished, which means we may be stuck in qmp_capabilities
command without being able to send any QMP commands.

QEMU solved this by introducing "defer" parameter for -incoming command
line option. This will tell QEMU to prepare for an incoming migration
while the actual incoming URI is sent using migrate-incoming QMP
command. Before calling this command we can normally talk to the
monitor and even set any migration parameters which will be honored by
the incoming migration.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
2015-11-19 09:41:23 +01:00
Jiri Denemark
04c721f22d qemu: Always set async job when starting a domain
We only started an async job for incoming migration from another host.
When we were starting a domain from scratch or restoring from a saved
state (migration from file) we didn't set any async job. Let's introduce
a new QEMU_ASYNC_JOB_START for these cases.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
2015-11-19 09:41:23 +01:00
Jiri Denemark
2bf5333f45 qemu: Introduce qemuProcessIncomingDef
Incoming migration may require quite a few parameters (URI, fd, path) to
be considered while starting QEMU and we will soon add another one.
Let's group all of them in a single struct.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
2015-11-19 09:41:23 +01:00
Jiri Denemark
34b9fe6101 qemu: Move incoming URI code to qemu_migration
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
2015-11-19 09:41:23 +01:00
Jiri Denemark
08600de376 qemu: Don't generate migration URI in qemuBuildCommandLine
Make callers of qemuBuildCommandLine responsible for providing the URI
which should be passed as a parameter for -incoming.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
2015-11-19 09:41:23 +01:00
Jiri Denemark
256fff39e4 qemu: Fix style in qemuProcessStart
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
2015-11-11 17:02:53 +01:00
Daniel P. Berrange
932534e85f qemu: assume 'info chardev' is always available
As of QEMU 0.11.0 the 'info chardev' monitor command can be
used to report on allocated chardev paths, so we can drop
support for parsing QEMU stderr to locate the PTY paths.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2015-11-10 10:38:01 +00:00
Jiri Denemark
630341a215 qemu: Fix memory leak in qemuProcessStart
nodeset should be freed in both success and failure paths.

While tmppath is freed immediately after it's consumed, moving it from
error to cleanup label is a bit more consistent and robust.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
2015-11-04 13:09:35 +01:00
Jiri Denemark
d65ab51d74 qemu: Introduce cleanup label in qemuProcessStart
Remove code duplication by moving common cleanup code in a dedicated
label.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
2015-11-04 13:09:35 +01:00
Jiri Denemark
93df3a9748 qemu: Rename ret variable in qemuProcessStart
Generally, we use "ret" variable for storing the value we are going to
return at the and of a function, but this is not the case in
qemuProcessStart. Let's rename "ret" as "rv".

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
2015-11-04 13:09:34 +01:00
Jiri Denemark
7404c40597 qemu: Rename cleanup label in qemuProcessStart
Current "cleanup" label is only used in error path, thus it should
rather be called "error".

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
2015-11-04 13:09:34 +01:00
Jiri Denemark
b33c33b7d5 qemu: Use correct type when calling qemuPrepareNVRAM
qemuProcessStart was passing char * migrateFrom as the third argument to
qemuPrepareNVRAM. We should explicitly convert the pointer to bool which
is what the function expects.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
2015-11-04 13:09:34 +01:00
Andrea Bolognani
66f319aec0 qemu: hostdev: Introduce qemuHostdevUpdateActiveDomainDevices()
This calls the PCI-, USB- and SCSI-specific functions just
like qemuHostdev{Prepare,ReAttach}DomainDevices() already do,
and was the missing piece for the qemuHostdev API to nicely
mirror the virHostdev API.

Update qemuProcessReconnect() to use the new function.
2015-10-26 13:50:35 +01:00
Andrea Bolognani
8da5cbfc78 qemu: hostdev: Unify naming for qemuHostdevUpdateActive*Devices()
Adopt the same names used for virHostdevUpdateActive*Devices() for
consistency's sake and to make it easier to jump between the two.

No functional changes.
2015-10-26 13:50:35 +01:00
Andrea Bolognani
5ab29e369f qemu: hostdev: Unify naming for qemuHostdevReAttach*Devices()
Adopt the same names used for virHostdevReAttach*Devices() for
consistency's sake and to make it easier to jump between the two.

No functional changes.
2015-10-26 13:50:35 +01:00
Andrea Bolognani
c074a64251 qemu: hostdev: Unify naming for qemuHostdevPrepare*Devices()
Adopt the same names used for virHostdevPrepare*Devices() for
consistency's sake and to make it easier to jump between the two.

No functional changes.
2015-10-26 13:50:35 +01:00
John Ferlan
cc2d49f9be qemu: Fix qemu startup check for QEMU_CAPS_OBJECT_IOTHREAD
https://bugzilla.redhat.com/show_bug.cgi?id=1249981

When qemuDomainPinIOThread was added in commit id 'fb562614', a check
for the IOThread capability was not needed since a check for iothreadpids
covered the condition where the support for IOThreads was not present.
The iothreadpids array was only created if qemuProcessDetectIOThreadPIDs
was able to query the monitor for IOThreads. It would only do that if
the QEMU_CAPS_OBJECT_IOTHREAD capability was set.

However, when iothreadids were added in commit id '8d4614a5' and the
check for iothreadpids was replaced by a search through the iothreadids[]
array for the matching iothread_id that left open the possibility that
an iothreadids[] array was defined, but the entries essentially pointed
to elements with only the 'iothread_id' defined leaving the 'thread_id'
value of 0 and eventually the cpumap entry of NULL.

This was because, the original IOThreads commit id '72edaae7' only
checked if IOThreads were defined and if the emulator had the IOThreads
capability, then IOThread objects were added at startup. The "capability
failure" check was only done when a disk was assigned to an IOThread in
qemuCheckIOThreads. This was because the initial implementation had no way
to dynamically add IOThreads, but it was possible to dynamically add a
disk to the domain. So the decision was if the domain supported it, then
add the IOThread objects. Then if a disk with an IOThread defined was
added, it could check the capability and fail to add if not there. This
just meant the 'iothreads' value was essentially ignored.

Eventually commit id 'a27ed6e7' allowed for the dynamic addition and
deletion of IOThread objects. So it was no longer necessary to generate
IOThread objects to dynamically attach a disk to. However, the startup
and disk check code was not modified to reflect this.

This patch will move the capability failure check to when IOThread
objects are being added to the command line. Thus a domain that has
IOThreads defined will not be started if the emulator doesn't support
the capability. This means when qemuCheckIOThreads is called to add
a disk, it's no longer necessary to check the capability. Instead the
code can use the IOThreadFind call to indicate that the IOThread
doesn't exist.

Finally because it could be possible to have a domain running with the
iothreadids[] defined prior to this change if libvirtd is restarted each
having mostly empty elements, qemuProcessDetectIOThreadPIDs will check
if there are niothreadids when the QEMU_CAPS_OBJECT_IOTHREAD capability
check fails and remove the elements and array if it exists.

With these changes in place, it turns out the cputune-numatune test
was failing because the right bit wasn't set in the test. So used the
opportunity to fix that and create a test that would expect to fail
with some sort of iothreads defined and used, but not having the
correct capability.
2015-10-16 06:55:45 -04:00
John Ferlan
4f8e888714 qemu: Use 'niothreadids' instead of 'iothreads'
Although theoretically both should be the same value, the niothreadids
should be used in favor of iothreads when performing comparisons. This
leaves the iothreads as a purely numeric value to be saved in the config
file.  The one exception to the rule is virDomainIOThreadIDDefArrayInit
where the iothreadids are being generated from the iothreads count since
iothreadids were added after initial iothreads support.
2015-10-16 06:49:19 -04:00
John Ferlan
0bc5fcffb1 qemu: Resolve Coverity FORWARD_NULL
Coverity notices that net->ifname is potentially referenced after a
VIR_FREE().  Since the net->ifname will eventually be free'd during
virDomainDefFree when calling virDomainNetDefFree, let's just that
processing take care the free.

Signed-off-by: John Ferlan <jferlan@redhat.com>
2015-10-07 18:42:38 -04:00
Peter Krempa
34315608a8 conf: Reuse virDomainDefCheckDuplicateDiskWWN to check disk serial too
Rename the function to virDomainDefCheckDuplicateDiskInfo and make it
check disk serials too.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1245013
2015-10-05 07:25:21 +02:00
Peter Krempa
199d17de32 qemu: Perform the disk WWN check only on fresh starts
Since we'd disallow migration of a guest that would have possibly
invalid config but still be able to work, relax the WWN check to be
performed only on new starts of the VM.
2015-10-05 07:25:21 +02:00
John Ferlan
ace8e2276e qemu: Resolve Coverity CHECKED_RETURN
Coverity complains that return from virHookCall is not checked in
one place in qemuProcessStop.  Since the comment notes that we cannot
stop the operation even it if fails, just added the ignore_value.
2015-09-24 09:53:39 -04:00
Michal Privoznik
f41be29635 qemu: Move vm->persistent check into qemuDomainRemoveInactive
So far we have the following pattern occurring over and over
again:

  if (!vm->persistent)
      qemuDomainRemoveInactive(driver, vm);

It's safe to put the check into the function and save some LoC.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
2015-09-24 10:52:38 +02:00
Peter Krempa
d7a0386e22 qemu: Refresh memory size only on fresh starts
Qemu unfortunately doesn't update internal state right after migration
and so the actual balloon size as returned by 'query-balloon' are
invalid for a while after the CPUs are started after migration. If we'd
refresh our internal state at this point we would report invalid current
memory size until the next balloon event would arrive.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1242940
2015-09-23 14:22:29 +02:00
Jiri Denemark
cda2afac79 qemuDomainEventQueue: Check if event is non-NULL
Every single call to qemuDomainEventQueue() uses the following pattern:

    if (event)
        qemuDomainEventQueue(driver, event);

Let's move the check for valid event to qemuDomainEventQueue and
simplify all callers.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
2015-09-18 13:50:03 +02:00
John Ferlan
b421a70811 virfile: Check for existence of dir in virFileDeleteTree
Commit id 'f1f68ca33' added code to remove the directory paths for
auto-generated sockets, but that code could be called before the
paths were created resulting in generating error messages from
virFileDeleteTree indicating that the file doesn't exist.

Rather than "enforce" all callers to make the non-NULL and existence
checks, modify the virFileDeleteTree API to silently ignore NULL on
input and non-existent directory trees.
2015-09-16 11:23:16 -04:00
Martin Kletzander
192a139489 qemu: Do not allow others into per-VM subdirectories
Signed-off-by: Martin Kletzander <mkletzan@redhat.com>
2015-09-14 10:06:00 +02:00
Martin Kletzander
8370023730 qemu: Report error if per-VM directory cannot be created
Commit f1f68ca334 did not report an error if virFileMakePath()
returned -1.  Well, who would've guessed function with name starting
with 'vir' sets an errno instead of reporting an error the libvirt way.
Anyway, let's fix it, so the output changes from:

  $ virsh start arm
  error: Failed to start domain arm
  error: An error occurred, but the cause is unknown

to:

  $ virsh start arm
  error: Failed to start domain arm
  error: Cannot create directory '/var/lib/libvirt/qemu/domain-arm': Not
  a directory

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1146886

Signed-off-by: Martin Kletzander <mkletzan@redhat.com>
2015-09-09 13:38:18 +02:00
Martin Kletzander
f674dc6794 qemu: Label correct per-VM path when starting
Commit f1f68ca334 overused mdir_name()
event though it was not needed in the latest version, hence labelling
directory one level up in the tree and not the one it should.

If anyone with SElinux managed to try run a domain with guest agent set
up, it's highly possible that they will need to run 'restorecon -F
/var/lib/libvirt/qemu/channel/target' to fix what was done.

Reported-by: Luyao Huang <lhuang@redhat.com>
Signed-off-by: Martin Kletzander <mkletzan@redhat.com>
2015-08-26 10:44:14 +02:00
Martin Kletzander
f1f68ca334 qemu: Fix access to auto-generated socket paths
We are automatically generating some socket paths for domains, but all
those paths end up in a directory that's the same for multiple domains.
The problem is that multiple domains can each run with different
seclabels (users, selinux contexts, etc.).  The idea here is to create a
per-domain directory labelled in a way that each domain can access its
own unix sockets.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1146886

Signed-off-by: Martin Kletzander <mkletzan@redhat.com>
2015-08-24 11:53:17 +02:00
Martin Kletzander
c43c661fe4 qemu: Remove double unlock for domains
The virDomainObjListRemove() function unlocks a domain that it's given
due to legacy code.  And because of that code, which should be
refactored, that last virObjectUnlock() cannot be just removed.  So
instead, lock it right back for qemu for now.  All calls to
qemuDomainRemoveInactive() are followed by code that unlocks the domain
again, plus the domain should be locked during qemuDomainObjEndJob(), so
the right place to lock it is right after virDomainObjListRemove().

The only place where this would cause a problem is the autodestroy
callback, so we need to get another reference there and uref+unlock it
afterwards.  Luckily, returning NULL from that function doesn't mean an
error, and only means that it doesn't need to be unlocked anymore.

Signed-off-by: Martin Kletzander <mkletzan@redhat.com>
2015-08-03 16:59:20 +02:00