The disk hotplug code also overloads media change which is not ideal.
This will allow splitting out of the media change code.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>

The disk storage source needs to be prepared if we want to use -blockdev
or secrets for the new media image. It does not hurt to do the same for
the legacy hotplug code as well.

Unfortunately helpers like qemuDomainPrepareDiskSource take
virDomainDiskDef as an argument and it would be hard to fix them to take
an explicit source, so the function also temporarily replaces disk->src
for the new source in this function.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>

Some functions require us to replace disk->src with the new source for
them to work properly. To avoid confusion all places which allow
explicit virStorageSource should get the appropriate definition.

The legacy code fortunately does not need anything from the old source
so that does not require modifications.

Blockdev does require the old definition so we'll pass it explicitly.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>

Since the code is also used when changing media we need to allow
specifying explicit source for which we are going to prepare. With this
change callers don't have to replace disk->src with the new source
definition for generating these.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>

qemu media changing code tried to assume old media's format for the new
one if that was not specified. Since the format will always be present
it does not make sense to keep the code around.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>

Old media changing code does not bother setting up the secrets for new
media or actually removing/adding of the corresponding objects.

Additionally it uses secrets setup for the old image to be removed as
the secret for the new image which is wrong.

Remove the support for secrets while changing media for the legacy
approach. The only reasonable way to fix it is when using blockdev.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>

While the idea was good the implementation not so much as we need to
take into account the old disk data and the new source. The code will be
consolidated later in a different way.

This reverts commit 663b1d55.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>

Preparing the storage source prior to assigning the alias will not work
as the names of the certain objects depend on the alias for the legacy
hotplug case as we generate the object names for the secrets based on
the alias.

This reverts commit 192fdaa6.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>

This enables to use both cgroup v1 and v2 at the same time together
with libvirt.  It is supported by kernel and there is valid use-case,
not all controllers are implemented in cgroup v2 so there might be
configurations where administrator would enable these missing
controllers in cgroup v1.
Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

All mandatory callbacks are implemented for cgroup v2 backend so we
can register it now.
Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

In order to set CPU cfs period using cgroup v2 'cpu.max' interface
we need to load the current value of CPU cfs quota first because
format of 'cpu.max' interface is '$quota $period' and in order to
change 'period' we need to write 'quota' as well.  Writing only one
number changes only 'quota'.
Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

In cgroups v2 we need to handle threads and processes differently.
If you need to move a process you need to write its pid into
cgrou.procs file and it will move the process with all its threads
as well.  The whole process will be moved if you use tid of any thread.

In order to move only threads at first we need to create threaded group
and after that we can write the relevant thread tids into cgroup.threads
file.  Threads can be moved only into cgroups that are children of
cgroup of its process.
Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

When creating cgroup hierarchy we need to enable controllers in the
parent cgroup in order to be usable.  That means writing "+{controller}"
into cgroup.subtree_control file.  We can enable only controllers that
are enabled for parent cgroup, that means we need to do that for the
whole cgroup tree.

Cgroups for threads needs to be handled differently in cgroup v2.  There
are two types of controllers:

    - domain controllers: these cannot be enabled for threads
    - threaded controllers: these can be enabled for threads

In addition there are multiple types of cgroups:

    - domain: normal cgroup
    - domain threaded: a domain cgroup that serves as root for threaded
                       cgroups
    - domain invalid: invalid cgroup, can be changed into threaded, this
                      is the default state if you create subgroup inside
                      domain threaded group or threaded group
    - threaded: threaded cgroup which can have domain threaded or
                threaded as parent group

In order to create threaded cgroup it's sufficient to write "threaded"
into cgroup.type file, it will automatically make parent cgroup
"domain threaded" if it was only "domain".  In case the parent cgroup
is already "domain threaded" or "threaded" it will modify only the type
of current cgroup.  After that we can enable threaded controllers.
Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

Signed-off-by: NPavel Hrdina <phrdina@redhat.com>