This way we do not rely on the size MAX* constants from the kernel headers, as these will
be out-of-sync in case we have old headers and new defines in missing.h.
With this change we understand more than just leaf quota groups for
btrfs file systems. Specifically:
- When we create a subvolume we can now optionally add the new subvolume
to all qgroups its parent subvolume was member of too. Alternatively
it is also possible to insert an intermediary quota group between the
parent's qgroups and the subvolume's leaf qgroup, which is useful for
a concept of "subtree" qgroups, that contain a subvolume and all its
children.
- The remove logic for subvolumes has been updated to optionally remove
any leaf qgroups or "subtree" qgroups, following the logic above.
- The snapshot logic for subvolumes has been updated to replicate the
original qgroup setup of the source, if it follows the "subtree"
design described above. It will not cover qgroup setups that introduce
arbitrary qgroups, especially those orthogonal to the subvolume
hierarchy.
This also tries to be more graceful when setting up /var/lib/machines as
btrfs. For example, if mkfs.btrfs is missing we don't even try to set it
up as loopback device.
Fixes#1559Fixes#1129
Track the number of matches installed for a given multicast group, and leave the
group once no matches depend on it.
In order to handle passed-in sockets that are already members of multicast groups
we initialize the refcount based on the membership once we take over the socket.
This way we will leave the socket in the state we found it once we finish with
it.
On kernels that do not fully support reading out the multicast group membership
we fall back to never leaving any groups (as before).
This adds support for caching harddisk passwords in the kernel keyring
if it is available, thus supporting caching without Plymouth being
around.
This is also useful for hooking up "gdm-auto-login" with the collected
boot-time harddisk password, in order to support gnome keyring
passphrase unlocking via the HDD password, if it is the same.
Any passwords added to the kernel keyring this way have a timeout of
2.5min at which time they are purged from the kernel.
This patch set adds full support the new unified cgroup hierarchy logic
of modern kernels.
A new kernel command line option "systemd.unified_cgroup_hierarchy=1" is
added. If specified the unified hierarchy is mounted to /sys/fs/cgroup
instead of a tmpfs. No further hierarchies are mounted. The kernel
command line option defaults to off. We can turn it on by default as
soon as the kernel's APIs regarding this are stabilized (but even then
downstream distros might want to turn this off, as this will break any
tools that access cgroupfs directly).
It is possibly to choose for each boot individually whether the unified
or the legacy hierarchy is used. nspawn will by default provide the
legacy hierarchy to containers if the host is using it, and the unified
otherwise. However it is possible to run containers with the unified
hierarchy on a legacy host and vice versa, by setting the
$UNIFIED_CGROUP_HIERARCHY environment variable for nspawn to 1 or 0,
respectively.
The unified hierarchy provides reliable cgroup empty notifications for
the first time, via inotify. To make use of this we maintain one
manager-wide inotify fd, and each cgroup to it.
This patch also removes cg_delete() which is unused now.
On kernel 4.2 only the "memory" controller is compatible with the
unified hierarchy, hence that's the only controller systemd exposes when
booted in unified heirarchy mode.
This introduces a new enum for enumerating supported controllers, plus a
related enum for the mask bits mapping to it. The core is changed to
make use of this everywhere.
This moves PID 1 into a new "init.scope" implicit scope unit in the root
slice. This is necessary since on the unified hierarchy cgroups may
either contain subgroups or processes but not both. PID 1 hence has to
move out of the root cgroup (strictly speaking the root cgroup is the
only one where processes and subgroups are still allowed, but in order
to support containers nicey, we move PID 1 into the new scope in all
cases.) This new unit is also used on legacy hierarchy setups. It's
actually pretty useful on all systems, as it can then be used to filter
journal messages coming from PID 1, and so on.
The root slice ("-.slice") is now implicitly created and started (and
does not require a unit file on disk anymore), since
that's where "init.scope" is located and the slice needs to be started
before the scope can.
To check whether we are in unified or legacy hierarchy mode we use
statfs() on /sys/fs/cgroup. If the .f_type field reports tmpfs we are in
legacy mode, if it reports cgroupfs we are in unified mode.
This patch set carefuly makes sure that cgls and cgtop continue to work
as desired.
When invoking nspawn as a service it will implicitly create two
subcgroups in the cgroup it is using, one to move the nspawn process
into, the other to move the actual container processes into. This is
done because of the requirement that cgroups may either contain
processes or other subgroups.
