This patch is mostly code motion - moving some functions out
of qemu_driver and into qemu_domain so they can be reused by
multiple qemu_* files (since qemu_driver.h must not grow).
It also adds a new helper function, qemuDomainRemoveInactive,
which will be used in the next patch.

* src/qemu/qemu_domain.h (qemuFindQemuImgBinary)
(qemuDomainSnapshotWriteMetadata, qemuDomainSnapshotForEachQcow2)
(qemuDomainSnapshotDiscard, qemuDomainSnapshotDiscardAll)
(qemuDomainRemoveInactive): New prototypes.
(struct qemu_snap_remove): New struct.
* src/qemu/qemu_domain.c (qemuDomainRemoveInactive)
(qemuDomainSnapshotDiscardAllMetadata): New functions.
(qemuFindQemuImgBinary, qemuDomainSnapshotWriteMetadata)
(qemuDomainSnapshotForEachQcow2, qemuDomainSnapshotDiscard)
(qemuDomainSnapshotDiscardAll): Move here...
* src/qemu/qemu_driver.c (qemuFindQemuImgBinary)
(qemuDomainSnapshotWriteMetadata, qemuDomainSnapshotForEachQcow2)
(qemuDomainSnapshotDiscard, qemuDomainSnapshotDiscardAll): ...from
here.
(qemuDomainUndefineFlags): Update caller.
* src/conf/domain_conf.c (virDomainRemoveInactive): Doc fixes.

Commit 19f8c980 introduced VIR_DOMAIN_UNDEFINE_SNAPSHOTS_METADATA,
with the intent that omitting the flag makes undefine fail, and
including the flag deletes metadata.  But it used the wrong logic.
Also, hoist the transient domain sooner, so that we don't
accidentally remove metadata of a transient domain.

* src/qemu/qemu_driver.c (qemuDomainUndefineFlags): Check correct
flag value.

* src/qemu/qemu_process.c: Taking if (qemuDomainObjEndJob(driver, obj) == 0)
  true branch then 'obj' is NULL, virDomainObjIsActive(obj) and
  virDomainObjUnref(obj) will dereference NULL pointer.
Signed-off-by: NAlex Jia <ajia@redhat.com>

Once virDomainReboot is called for a domain, guest OS initiated shutdown
would always result in reboot instead of shutdown. Only
virDomainShutdown would actually shutd such domain down. That's because
we forgot to reset fakeReboot flag once we asked the domain to reboot.

The commit that prevents disk corruption on domain shutdown
(96fc4784) causes regression with QEMU
0.14.* and 0.15.* because of a regression bug in QEMU that was fixed
only recently in QEMU git. The affected versions of QEMU do not quit on
SIGTERM if started with -no-shutdown, which we use to implement fake
reboot. Since -no-shutdown tells QEMU not to quit automatically on guest
shutdown, domains started using the affected QEMU cannot be shutdown
properly and stay in a paused state.

This patch disables fake reboot feature on such QEMU by not using
-no-shutdown, which makes shutdown work as expected. However,
virDomainReboot will not work in this case and it will report "Requested
operation is not valid: Reboot is not supported with this QEMU binary".

gcc warns when building libvirt 0.9.5 on a 32-bit machine:

qemu/qemu_migration.c: In function 'qemuMigrationToFile':
qemu/qemu_migration.c:2727:38: error: large integer implicitly truncated to unsigned type [-Woverflow]

* src/qemu/qemu_domain.h (QEMU_DOMAIN_FILE_MIG_BANDWIDTH_MAX): Cap
to long when building for 32-bit platform.

Virsh man page lists driver types to be used with attach-device
command, but does not specify that those are usable only with the XEN
Hypervisor.

This patch adds statement, that those options specified are applicable
only on the Xen hypervisor and adds option usable with qemu emulator.

This patch also changes type of error returned by QEMU driver if the
user specifies incompatible driver type from VIR_ERR_INTERNAL_ERROR to
VIR_ERR_CONFIG_UNSUPPORTED.

Leak introduced in commit 036ad505, affects only error case.

* src/qemu/qemu_command.c: fix memory leak.
Signed-off-by: NAlex Jia <ajia@redhat.com>

For all types of disks other than qcow2, we were requesting that
SELinux labeling visit the new file as if it were qcow2, which
means labeling would try to find the backing files of an empty file.
And for a pre-existing qcow2 disk, we were passing NULL, which meant
that labelling tried to probe the file type (and if probing is
disabled, per the default qemu.conf, this made snapshots fail).
What we really want is to make SELinux labeling visit the new
file as raw; it will later be converted to qcow2 if qemu successfully
made the snapshot.

* src/qemu/qemu_driver.c
(qemuDomainSnapshotCreateSingleDiskActive): Force SELinux labeling
to avoid probe of new file.

For external snapshots to be useful on persistent domains, we must
alter the persistent definition alongside the running definition.
Thanks to the possibility of disk hotplug as well as of edits that
only affect the persistent xml, we can't assume that vm->def and
vm->newDef have the same disk at the same index, so we can only
update the persistent copy if the device destination matches up.

* src/qemu/qemu_driver.c (qemuDomainSnapshotCreateDiskActive)
(qemuDomainSnapshotCreateSingleDiskActive): Also affect newDef, if
present.

* src/qemu/qemu_command.c: missing return value check.
Signed-off-by: NAlex Jia <ajia@redhat.com>

Qemu sends STOP event as part of the shutdown process. Detect such STOP
event and consider shutdown to be reason of emitting such event. That's
the best we can do until qemu provides us the reason directly in STOP
event. This allows us to report shutdown reason for paused state so that
apps can detect domains that failed to finish the shutdown process
(e.g., because qemu is buggy and doesn't exit on SIGTERM or it is
blocked in flushing disk buffers).

Ever since we introduced fake reboot, we call qemuProcessKill as a
reaction to SHUTDOWN event. Unfortunately, qemu doesn't guarantee it
flushed all internal buffers before sending SHUTDOWN, in which case
killing the process forcibly may result in (virtual) disk corruption.

By sending just SIGTERM without SIGKILL we give qemu time to to flush
all buffers and exit. Once qemu exits, we will see an EOF on monitor
connection and tear down the domain. In case qemu ignores SIGTERM or
just hangs there, the process stays running but that's not any different
from a possible hang anytime during the shutdown process so I think it's
just fine.

Also qemu (since 0.14 until it's fixed) has a bug in SIGTERM processing
which causes it not to exit but instead send new SHUTDOWN event and keep
waiting. I think the best we can do is to ignore duplicate SHUTDOWN
events to avoid a SHUTDOWN-SIGTERM loop and leave the domain in paused
state.

When a domain is rebooted using libvirt API, we use fake reboot
consisting of shutting down and resetting the domain. Thus we see a
SHUTDOWN event and set gotShutdown flag. But we never reset it back and
if the domain crashes after it was rebooted this way, we consider it was
a normal shutdown and not a crash.

Commit 4454a9ef changed shutoff reason
from VIR_DOMAIN_SHUTOFF_CRASHED to VIR_DOMAIN_SHUTOFF_FAILED in case we
see an unexpected EOF on monitor connection. But FAILED reason is
dedicated for domains that fail to start. CRASHED reason is the right
one to use in this situation.

This patch fixes the bug shown in bugzilla 738778. It's not an nwfilter problem but a connection sharing / closure issue.

https://bugzilla.redhat.com/show_bug.cgi?id=738778

Depending on the speed / #CPUs of the machine you are using you may not see this bug all the time.

/usr/lib/stdlib.h in Mac OS X and probably also in BSD's
exports this symbol :(

Pushing under build-breaker rule.

Adjust qemuMigrationRun() to use migMaxBandwidth in qemuDomainObjPrivate
structure when setting qemu migration speed.  Caller-specified 'resource'
parameter overrides migMaxBandwidth.

The qemu migration speed default is 32MiB/s as defined in migration.c

/* Migration speed throttling */
static int64_t max_throttle = (32 << 20);

There's no need to throttle migration when targeting a file, so set migration
speed to unlimited prior to migration, and restore to libvirt default value
after migration.

Default units is MB for migrate_set_speed monitor command, so
(INT64_MAX / (1024 * 1024)) is used for unlimited migration speed.

Tested with both json and text monitors.

Now that migration speed is stored in qemuDomainObjPrivate structure,
save the new value when invoking qemuDomainMigrateSetMaxSpeed().

Allow setting migration speed on inactive domain too.

The maximum bandwidth that can be consumed when migrating a domain
is better classified as an operational vs configuration parameter of
the dommain.  As such, store this parameter in qemuDomainObjPrivate
structure.

Commit 498d7833 cleans up some of virtual file names for parsing strings
in memory. This patch cleans up (hopefuly) the rest forgotten by the
first patch.

This patch also changes all of the previously modified "filenames" to
valid URI's replacing spaces for underscores.

Changes to v1:
- Replace all spaces for underscores, so that the strings form valid
  URI's
- Replace spaces in places changed by commit 498d7833

Regression introduced in commit 3881a470, due to an improper rebase
of a cleanup written beforehand but only applied after a rebased of
a refactoring that created a new function in commit 25fb3ef1.

Also avoids passing NULL to printf %s.

* src/qemu/qemu_driver.c: In qemuDomainSnapshotForEachQcow2()
it free up the memory of qemu_driver->qemuImgBinary in the
cleanup tag which leads to the garbage value of qemuImgBinary
in qemu_driver struct and libvirtd crash when running
"virsh snapshot-create" command a second time.
Signed-off-by: NEric Blake <eblake@redhat.com>

Regression introduced in commit 89b6284f, due to an incorrect
conversion to the new means of converting disk names back to
the correct object.

* src/qemu/qemu_driver.c (qemuDomainGetBlockInfo): Avoid NULL deref.

This patch enables modifying network device configuration using the
virUpdateDeviceFlags API method. Matching of devices is accomplished
using MAC addresses.

While updating live configuration of a running domain, the user is
allowed only to change link state of the interface. Additional
modifications may be added later. For now the code checks for
unsupported changes and thereafter changes the link state, if
applicable.

When updating persistent configuration of guest's network interface the
whole configuration (except for the MAC address) may be modified and
is stored for the next startup.

* src/qemu/qemu_driver.c   - Add dispatching of virUpdateDevice for
                             network devices update (live/config)
* src/qemu/qemu_hotplug.c  - add setting of initial link state on live
                             device addition
                           - add function to change network device
                             configuration. By now it supports only
                             changing of link state
* src/qemu/qemu_hotplug.h  - Headers to above functions
* src/qemu/qemu_process.c  - set link states before virtual machine
                             start. Qemu does not support setting of
                             this on the command line.

This patch adds handlers for modification of guest's interface
link state. Both HMP and QMP commands are supported, but as the
link state functionality is from the beginning supported in QMP
the HMP code will probably never be used.

The mainly changes are:

1) Update qemuMonitorGetBlockStatsInfo and it's children (Text/JSON)
   functions to return the value of new latency fields.
2) Add new function qemuMonitorGetBlockStatsParamsNumber, which is
   to count how many parameters the underlying QEMU supports.
3) Update virDomainBlockStats in src/qemu/qemu_driver.c to be
   compatible with the changes by 1).

If libvirt daemon gets restarted and there is (at least) one
unresponsive qemu, the startup procedure hangs up. This patch creates
one thread per vm in which we try to reconnect to monitor. Therefore,
blocking in one thread will not affect other APIs.

This patch creates an optional BeginJob queue size limit. When
active, all other attempts above level will fail. To set this
feature assign desired value to max_queued variable in qemu.conf.
Setting it to 0 turns it off.

This patch annotates APIs with low or high priority.
In low set MUST be all APIs which might eventually access monitor
(and thus block indefinitely). Other APIs may be marked as high
priority. However, some must be (e.g. domainDestroy).

For high priority calls (HPC), there are some high priority workers
(HPW) created in the pool. HPW can execute only HPC, although normal
worker can process any call regardless priority. Therefore, only those
APIs which are guaranteed to end in reasonable small amount of time
can be marked as HPC.

The size of this HPC pool is static, because HPC are expected to end
quickly, therefore jobs assigned to this pool will be served quickly.
It can be configured in libvirtd.conf via prio_workers variable.
Default is set to 5.

To mark API with low or high priority, append priority:{low|high} to
it's comment in src/remote/remote_protocol.x. This is similar to
autogen|skipgen. If not marked, the generator assumes low as default.

With this, it is now possible to create external snapshots even
when SELinux is enforcing, and to protect the new file with a
lock manager.

* src/qemu/qemu_driver.c
(qemuDomainSnapshotCreateSingleDiskActive): Create and register
new file with proper permissions and locks.
(qemuDomainSnapshotCreateDiskActive): Update caller.

Lots of earlier patches led up to this point - the qemu snapshot_blkdev
monitor command can now be controlled by libvirt!  Well, insofar as
SELinux doesn't prevent qemu from open(O_CREAT) on the files.  There's
still some followup work before things work with SELinux enforcing,
but this patch is big enough to post now.

There's still room for other improvements, too (for example, taking a
disk snapshot of an inactive domain, by using qemu-img for both internal
and external snapshots; wiring up delete and revert control, including
additional flags from my RFC; supporting active QED disk snapshots;
supporting per-storage-volume snapshots such as LVM or btrfs snapshots;
etc.).  But this patch is the one that proves the new XML works!

* src/qemu/qemu_driver.c (qemuDomainSnapshotCreateXML): Wire in
active disk snapshots.
(qemuDomainSnapshotDiskPrepare)
(qemuDomainSnapshotCreateDiskActive)
(qemuDomainSnapshotCreateSingleDiskActive): New functions.

No one uses this yet, but it will be important once
virDomainSnapshotCreateXML learns a VIR_DOMAIN_SNAPSHOT_DISK_ONLY
flag, and the xml allows passing in the new file names.

* src/qemu/qemu_monitor.h (qemuMonitorDiskSnapshot): New prototype.
* src/qemu/qemu_monitor_text.h (qemuMonitorTextDiskSnapshot):
Likewise.
* src/qemu/qemu_monitor_json.h (qemuMonitorJSONDiskSnapshot):
Likewise.
* src/qemu/qemu_monitor.c (qemuMonitorDiskSnapshot): New
function.
* src/qemu/qemu_monitor_json.c (qemuMonitorJSONDiskSnapshot):
Likewise.

Snapshots alter the set of disk image files opened by qemu, so
they must be audited.  But they don't involve a full disk definition
structure, just the new filename.  Make the next patch easier by
refactoring the audit routines to just operate on file name.

* src/conf/domain_audit.h (virDomainAuditDisk): Update prototype.
* src/conf/domain_audit.c (virDomainAuditDisk): Act on strings,
not definition structures.
(virDomainAuditStart): Update caller.
* src/qemu/qemu_hotplug.c (qemuDomainChangeEjectableMedia)
(qemuDomainAttachPciDiskDevice, qemuDomainAttachSCSIDisk)
(qemuDomainAttachUsbMassstorageDevice)
(qemuDomainDetachPciDiskDevice, qemuDomainDetachDiskDevice):
Likewise.

My RFC for snapshot support [1] proposes several rules for when it is
safe to delete or revert to an external snapshot, predicated on
the existence of new API flags.  These will be incrementally added
in future patches, but until then, blindly mishandling a disk
snapshot risks corrupting internal state, so it is better to
outright reject the attempts until the other pieces are in place,
thus incrementally relaxing the restrictions added in this patch.

[1] https://www.redhat.com/archives/libvir-list/2011-August/msg00361.html

* src/qemu/qemu_driver.c (qemuDomainSnapshotCountExternal): New
function.
(qemuDomainUndefineFlags, qemuDomainSnapshotDelete): Use it to add
safety valve.
(qemuDomainRevertToSnapshot, qemuDomainSnapshotCreateXML): Add safety
valve.

Prior to this patch, <domainsnapshot>/<disks> was ignored.  This
changes it to be an error unless an explicit disk snapshot is
requested (a future patch may relax things if it turns out to
be useful to have a <disks> specification alongside a system
checkpoint).

* include/libvirt/libvirt.h.in
(VIR_DOMAIN_SNAPSHOT_CREATE_DISK_ONLY): New flag.
* src/libvirt.c (virDomainSnapshotCreateXML): Document it.
* src/esx/esx_driver.c (esxDomainSnapshotCreateXML): Disk
snapshots not supported yet.
* src/vbox/vbox_tmpl.c (vboxDomainSnapshotCreateXML): Likewise.
* src/qemu/qemu_driver.c (qemuDomainSnapshotCreateXML): Likewise.

I got confused when 'virsh domblkinfo dom disk' required the
path to a disk (which can be ambiguous, since a single file
can back multiple disks), rather than the unambiguous target
device name that I was using in disk snapshots.  So, in true
developer fashion, I went for the best of both worlds - all
interfaces that operate on a disk (aka block) now accept
either the target name or the unambiguous path to the backing
file used by the disk.

* src/conf/domain_conf.h (virDomainDiskIndexByName): Add
parameter.
(virDomainDiskPathByName): New prototype.
* src/libvirt_private.syms (domain_conf.h): Export it.
* src/conf/domain_conf.c (virDomainDiskIndexByName): Also allow
searching by path, and decide whether ambiguity is okay.
(virDomainDiskPathByName): New function.
(virDomainDiskRemoveByName, virDomainSnapshotAlignDisks): Update
callers.
* src/qemu/qemu_driver.c (qemudDomainBlockPeek)
(qemuDomainAttachDeviceConfig, qemuDomainUpdateDeviceConfig)
(qemuDomainGetBlockInfo, qemuDiskPathToAlias): Likewise.
* src/qemu/qemu_process.c (qemuProcessFindDomainDiskByPath):
Likewise.
* src/libxl/libxl_driver.c (libxlDomainAttachDeviceDiskLive)
(libxlDomainDetachDeviceDiskLive, libxlDomainAttachDeviceConfig)
(libxlDomainUpdateDeviceConfig): Likewise.
* src/uml/uml_driver.c (umlDomainBlockPeek): Likewise.
* src/xen/xend_internal.c (xenDaemonDomainBlockPeek): Likewise.
* docs/formatsnapshot.html.in: Update documentation.
* tools/virsh.pod (domblkstat, domblkinfo): Likewise.
* docs/schemas/domaincommon.rng (diskTarget): Tighten pattern on
disk targets.
* docs/schemas/domainsnapshot.rng (disksnapshot): Update to match.
* tests/domainsnapshotxml2xmlin/disk_snapshot.xml: Update test.