asterinas/kernel/src/fs/cgroupfs/fs.rs

106 lines
2.5 KiB
Rust

// SPDX-License-Identifier: MPL-2.0
use alloc::sync::Arc;
use aster_block::BlockDevice;
use aster_systree::EmptyNode;
use spin::Once;
use super::inode::CgroupInode;
use crate::{
fs::{
Result,
cgroupfs::systree_node::CgroupSystem,
registry::{FsProperties, FsType},
utils::{
FileSystem, FsEventSubscriberStats, FsFlags, Inode, SuperBlock,
systree_inode::SysTreeInodeTy,
},
},
prelude::*,
};
/// A file system for managing cgroups.
pub(super) struct CgroupFs {
sb: SuperBlock,
root: Arc<dyn Inode>,
fs_event_subscriber_stats: FsEventSubscriberStats,
}
// Magic number for cgroupfs v2 (taken from Linux)
const MAGIC_NUMBER: u64 = 0x63677270;
const BLOCK_SIZE: usize = 4096;
const NAME_MAX: usize = 255;
impl CgroupFs {
/// Returns the `CgroupFs` singleton.
pub(super) fn singleton() -> &'static Arc<CgroupFs> {
static SINGLETON: Once<Arc<CgroupFs>> = Once::new();
SINGLETON.call_once(|| Self::new(CgroupSystem::singleton().clone()))
}
fn new(root_node: Arc<CgroupSystem>) -> Arc<Self> {
let dev_id = device_id::PSEUDO_FS_DEVICE_ID_ALLOCATOR
.get()
.expect("PSEUDO_FS_DEVICE_ID_ALLOCATOR not initialized")
.allocate();
let sb = SuperBlock::new(MAGIC_NUMBER, BLOCK_SIZE, NAME_MAX, dev_id);
let root_inode = CgroupInode::new_root(root_node);
Arc::new(Self {
sb,
root: root_inode,
fs_event_subscriber_stats: FsEventSubscriberStats::new(),
})
}
}
impl FileSystem for CgroupFs {
fn name(&self) -> &'static str {
"cgroup2"
}
fn sync(&self) -> Result<()> {
// CgroupFs is volatile, sync is a no-op
Ok(())
}
fn root_inode(&self) -> Arc<dyn Inode> {
self.root.clone()
}
fn sb(&self) -> SuperBlock {
self.sb.clone()
}
fn fs_event_subscriber_stats(&self) -> &FsEventSubscriberStats {
&self.fs_event_subscriber_stats
}
}
pub(super) struct CgroupFsType;
impl FsType for CgroupFsType {
fn name(&self) -> &'static str {
"cgroup2"
}
fn properties(&self) -> FsProperties {
FsProperties::empty()
}
fn create(
&self,
_flags: FsFlags,
_args: Option<CString>,
_disk: Option<Arc<dyn BlockDevice>>,
) -> Result<Arc<dyn FileSystem>> {
Ok(CgroupFs::singleton().clone() as _)
}
fn sysnode(&self) -> Option<Arc<dyn aster_systree::SysNode>> {
Some(EmptyNode::new("cgroup".into()))
}
}