Systemd/src/core/dbus-mount.c
Lennart Poettering 5af8805872 cgroup: drastically simplify caching of cgroups members mask
Previously we tried to be smart: when a new unit appeared and it only
added controllers to the cgroup mask we'd update the cached members mask
in all parents by ORing in the controller flags in their cached values.
Unfortunately this was quite broken, as we missed some conditions when
this cache had to be reset (for example, when a unit got unloaded),
moreover the optimization doesn't work when a controller is removed
anyway (as in that case there's no other way for the parent to iterate
though all children if any other, remaining child unit still needs it).
Hence, let's simplify the logic substantially: instead of updating the
cache on the right events (which we didn't get right), let's simply
invalidate the cache, and generate it lazily when we encounter it later.
This should actually result in better behaviour as we don't have to
calculate the new members mask for a whole subtree whever we have the
suspicion something changed, but can delay it to the point where we
actually need the members mask.

This allows us to simplify things quite a bit, which is good, since
validating this cache for correctness is hard enough.

Fixes: #9512
2018-11-23 13:41:37 +01:00

153 lines
6.5 KiB
C

/* SPDX-License-Identifier: LGPL-2.1+ */
#include "bus-util.h"
#include "dbus-cgroup.h"
#include "dbus-execute.h"
#include "dbus-kill.h"
#include "dbus-mount.h"
#include "dbus-util.h"
#include "mount.h"
#include "string-util.h"
#include "unit.h"
static const char *mount_get_what(const Mount *m) {
if (m->from_proc_self_mountinfo && m->parameters_proc_self_mountinfo.what)
return m->parameters_proc_self_mountinfo.what;
if (m->from_fragment && m->parameters_fragment.what)
return m->parameters_fragment.what;
return NULL;
}
static const char *mount_get_options(const Mount *m) {
if (m->from_proc_self_mountinfo && m->parameters_proc_self_mountinfo.options)
return m->parameters_proc_self_mountinfo.options;
if (m->from_fragment && m->parameters_fragment.options)
return m->parameters_fragment.options;
return NULL;
}
static const char *mount_get_fstype(const Mount *m) {
if (m->from_proc_self_mountinfo && m->parameters_proc_self_mountinfo.fstype)
return m->parameters_proc_self_mountinfo.fstype;
else if (m->from_fragment && m->parameters_fragment.fstype)
return m->parameters_fragment.fstype;
return NULL;
}
static BUS_DEFINE_PROPERTY_GET(property_get_what, "s", Mount, mount_get_what);
static BUS_DEFINE_PROPERTY_GET(property_get_options, "s", Mount, mount_get_options);
static BUS_DEFINE_PROPERTY_GET(property_get_type, "s", Mount, mount_get_fstype);
static BUS_DEFINE_PROPERTY_GET_ENUM(property_get_result, mount_result, MountResult);
const sd_bus_vtable bus_mount_vtable[] = {
SD_BUS_VTABLE_START(0),
SD_BUS_PROPERTY("Where", "s", NULL, offsetof(Mount, where), SD_BUS_VTABLE_PROPERTY_CONST),
SD_BUS_PROPERTY("What", "s", property_get_what, 0, SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE),
SD_BUS_PROPERTY("Options","s", property_get_options, 0, SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE),
SD_BUS_PROPERTY("Type", "s", property_get_type, 0, SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE),
SD_BUS_PROPERTY("TimeoutUSec", "t", bus_property_get_usec, offsetof(Mount, timeout_usec), SD_BUS_VTABLE_PROPERTY_CONST),
SD_BUS_PROPERTY("ControlPID", "u", bus_property_get_pid, offsetof(Mount, control_pid), SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE),
SD_BUS_PROPERTY("DirectoryMode", "u", bus_property_get_mode, offsetof(Mount, directory_mode), SD_BUS_VTABLE_PROPERTY_CONST),
SD_BUS_PROPERTY("SloppyOptions", "b", bus_property_get_bool, offsetof(Mount, sloppy_options), SD_BUS_VTABLE_PROPERTY_CONST),
SD_BUS_PROPERTY("LazyUnmount", "b", bus_property_get_bool, offsetof(Mount, lazy_unmount), SD_BUS_VTABLE_PROPERTY_CONST),
SD_BUS_PROPERTY("ForceUnmount", "b", bus_property_get_bool, offsetof(Mount, force_unmount), SD_BUS_VTABLE_PROPERTY_CONST),
SD_BUS_PROPERTY("Result", "s", property_get_result, offsetof(Mount, result), SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE),
SD_BUS_PROPERTY("UID", "u", bus_property_get_uid, offsetof(Unit, ref_uid), SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE),
SD_BUS_PROPERTY("GID", "u", bus_property_get_gid, offsetof(Unit, ref_gid), SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE),
BUS_EXEC_COMMAND_VTABLE("ExecMount", offsetof(Mount, exec_command[MOUNT_EXEC_MOUNT]), SD_BUS_VTABLE_PROPERTY_EMITS_INVALIDATION),
BUS_EXEC_COMMAND_VTABLE("ExecUnmount", offsetof(Mount, exec_command[MOUNT_EXEC_UNMOUNT]), SD_BUS_VTABLE_PROPERTY_EMITS_INVALIDATION),
BUS_EXEC_COMMAND_VTABLE("ExecRemount", offsetof(Mount, exec_command[MOUNT_EXEC_REMOUNT]), SD_BUS_VTABLE_PROPERTY_EMITS_INVALIDATION),
SD_BUS_VTABLE_END
};
static int bus_mount_set_transient_property(
Mount *m,
const char *name,
sd_bus_message *message,
UnitWriteFlags flags,
sd_bus_error *error) {
Unit *u = UNIT(m);
assert(m);
assert(name);
assert(message);
flags |= UNIT_PRIVATE;
if (streq(name, "Where"))
return bus_set_transient_path(u, name, &m->where, message, flags, error);
if (streq(name, "What"))
return bus_set_transient_string(u, name, &m->parameters_fragment.what, message, flags, error);
if (streq(name, "Options"))
return bus_set_transient_string(u, name, &m->parameters_fragment.options, message, flags, error);
if (streq(name, "Type"))
return bus_set_transient_string(u, name, &m->parameters_fragment.fstype, message, flags, error);
if (streq(name, "TimeoutUSec"))
return bus_set_transient_usec_fix_0(u, name, &m->timeout_usec, message, flags, error);
if (streq(name, "DirectoryMode"))
return bus_set_transient_mode_t(u, name, &m->directory_mode, message, flags, error);
if (streq(name, "SloppyOptions"))
return bus_set_transient_bool(u, name, &m->sloppy_options, message, flags, error);
if (streq(name, "LazyUnmount"))
return bus_set_transient_bool(u, name, &m->lazy_unmount, message, flags, error);
if (streq(name, "ForceUnmount"))
return bus_set_transient_bool(u, name, &m->force_unmount, message, flags, error);
return 0;
}
int bus_mount_set_property(
Unit *u,
const char *name,
sd_bus_message *message,
UnitWriteFlags flags,
sd_bus_error *error) {
Mount *m = MOUNT(u);
int r;
assert(m);
assert(name);
assert(message);
r = bus_cgroup_set_property(u, &m->cgroup_context, name, message, flags, error);
if (r != 0)
return r;
if (u->transient && u->load_state == UNIT_STUB) {
/* This is a transient unit, let's load a little more */
r = bus_mount_set_transient_property(m, name, message, flags, error);
if (r != 0)
return r;
r = bus_exec_context_set_transient_property(u, &m->exec_context, name, message, flags, error);
if (r != 0)
return r;
r = bus_kill_context_set_transient_property(u, &m->kill_context, name, message, flags, error);
if (r != 0)
return r;
}
return 0;
}
int bus_mount_commit_properties(Unit *u) {
assert(u);
unit_invalidate_cgroup_members_masks(u);
unit_realize_cgroup(u);
return 0;
}