garage/src/block/repair.rs

466 lines
12 KiB
Rust

use core::ops::Bound;
use std::path::PathBuf;
use std::sync::Arc;
use std::time::Duration;
use async_trait::async_trait;
use serde::{Deserialize, Serialize};
use tokio::fs;
use tokio::select;
use tokio::sync::mpsc;
use tokio::sync::watch;
use garage_util::background::*;
use garage_util::data::*;
use garage_util::error::*;
use garage_util::persister::Persister;
use garage_util::time::*;
use garage_util::tranquilizer::Tranquilizer;
use crate::manager::*;
// Full scrub every 30 days
const SCRUB_INTERVAL: Duration = Duration::from_secs(3600 * 24 * 30);
// Scrub tranquility is initially set to 4, but can be changed in the CLI
// and the updated version is persisted over Garage restarts
const INITIAL_SCRUB_TRANQUILITY: u32 = 4;
// ---- ---- ----
// FIRST KIND OF REPAIR: FINDING MISSING BLOCKS/USELESS BLOCKS
// This is a one-shot repair operation that can be launched,
// checks everything, and then exits.
// ---- ---- ----
pub struct RepairWorker {
manager: Arc<BlockManager>,
next_start: Option<Hash>,
block_iter: Option<BlockStoreIterator>,
}
impl RepairWorker {
pub fn new(manager: Arc<BlockManager>) -> Self {
Self {
manager,
next_start: None,
block_iter: None,
}
}
}
#[async_trait]
impl Worker for RepairWorker {
fn name(&self) -> String {
"Block repair worker".into()
}
fn info(&self) -> Option<String> {
match self.block_iter.as_ref() {
None => {
let idx_bytes = self
.next_start
.as_ref()
.map(|x| x.as_slice())
.unwrap_or(&[]);
let idx_bytes = if idx_bytes.len() > 4 {
&idx_bytes[..4]
} else {
idx_bytes
};
Some(format!("Phase 1: {}", hex::encode(idx_bytes)))
}
Some(bi) => Some(format!("Phase 2: {:.2}% done", bi.progress() * 100.)),
}
}
async fn work(&mut self, _must_exit: &mut watch::Receiver<bool>) -> Result<WorkerState, Error> {
match self.block_iter.as_mut() {
None => {
// Phase 1: Repair blocks from RC table.
// We have to do this complicated two-step process where we first read a bunch
// of hashes from the RC table, and then insert them in the to-resync queue,
// because of SQLite. Basically, as long as we have an iterator on a DB table,
// we can't do anything else on the DB. The naive approach (which we had previously)
// of just iterating on the RC table and inserting items one to one in the resync
// queue can't work here, it would just provoke a deadlock in the SQLite adapter code.
// This is mostly because the Rust bindings for SQLite assume a worst-case scenario
// where SQLite is not compiled in thread-safe mode, so we have to wrap everything
// in a mutex (see db/sqlite_adapter.rs and discussion in PR #322).
// TODO: maybe do this with tokio::task::spawn_blocking ?
let mut batch_of_hashes = vec![];
let start_bound = match self.next_start.as_ref() {
None => Bound::Unbounded,
Some(x) => Bound::Excluded(x.as_slice()),
};
for entry in self
.manager
.rc
.rc
.range::<&[u8], _>((start_bound, Bound::Unbounded))?
{
let (hash, _) = entry?;
let hash = Hash::try_from(&hash[..]).unwrap();
batch_of_hashes.push(hash);
if batch_of_hashes.len() >= 1000 {
break;
}
}
if batch_of_hashes.is_empty() {
// move on to phase 2
self.block_iter = Some(BlockStoreIterator::new(&self.manager));
return Ok(WorkerState::Busy);
}
for hash in batch_of_hashes.into_iter() {
self.manager
.resync
.put_to_resync(&hash, Duration::from_secs(0))?;
self.next_start = Some(hash)
}
Ok(WorkerState::Busy)
}
Some(bi) => {
// Phase 2: Repair blocks actually on disk
// Lists all blocks on disk and adds them to the resync queue.
// This allows us to find blocks we are storing but don't actually need,
// so that we can offload them if necessary and then delete them locally.
if let Some(hash) = bi.next().await? {
self.manager
.resync
.put_to_resync(&hash, Duration::from_secs(0))?;
Ok(WorkerState::Busy)
} else {
Ok(WorkerState::Done)
}
}
}
}
async fn wait_for_work(&mut self, _must_exit: &watch::Receiver<bool>) -> WorkerState {
unreachable!()
}
}
// ---- ---- ----
// SECOND KIND OF REPAIR: SCRUBBING THE DATASTORE
// This is significantly more complex than the process above,
// as it is a continuously-running task that triggers automatically
// every SCRUB_INTERVAL, but can also be triggered manually
// and whose parameter (esp. speed) can be controlled at runtime.
// ---- ---- ----
pub struct ScrubWorker {
manager: Arc<BlockManager>,
rx_cmd: mpsc::Receiver<ScrubWorkerCommand>,
work: ScrubWorkerState,
tranquilizer: Tranquilizer,
persister: Persister<ScrubWorkerPersisted>,
persisted: ScrubWorkerPersisted,
}
#[derive(Serialize, Deserialize)]
struct ScrubWorkerPersisted {
tranquility: u32,
time_last_complete_scrub: u64,
corruptions_detected: u64,
}
enum ScrubWorkerState {
Running(BlockStoreIterator),
Paused(BlockStoreIterator, u64), // u64 = time when to resume scrub
Finished,
}
impl Default for ScrubWorkerState {
fn default() -> Self {
ScrubWorkerState::Finished
}
}
#[derive(Debug)]
pub enum ScrubWorkerCommand {
Start,
Pause(Duration),
Resume,
Cancel,
SetTranquility(u32),
}
impl ScrubWorker {
pub fn new(manager: Arc<BlockManager>, rx_cmd: mpsc::Receiver<ScrubWorkerCommand>) -> Self {
let persister = Persister::new(&manager.system.metadata_dir, "scrub_info");
let persisted = match persister.load() {
Ok(v) => v,
Err(_) => ScrubWorkerPersisted {
time_last_complete_scrub: 0,
tranquility: INITIAL_SCRUB_TRANQUILITY,
corruptions_detected: 0,
},
};
Self {
manager,
rx_cmd,
work: ScrubWorkerState::Finished,
tranquilizer: Tranquilizer::new(30),
persister,
persisted,
}
}
async fn handle_cmd(&mut self, cmd: ScrubWorkerCommand) {
match cmd {
ScrubWorkerCommand::Start => {
self.work = match std::mem::take(&mut self.work) {
ScrubWorkerState::Finished => {
let iterator = BlockStoreIterator::new(&self.manager);
ScrubWorkerState::Running(iterator)
}
work => {
error!("Cannot start scrub worker: already running!");
work
}
};
}
ScrubWorkerCommand::Pause(dur) => {
self.work = match std::mem::take(&mut self.work) {
ScrubWorkerState::Running(it) | ScrubWorkerState::Paused(it, _) => {
ScrubWorkerState::Paused(it, now_msec() + dur.as_millis() as u64)
}
work => {
error!("Cannot pause scrub worker: not running!");
work
}
};
}
ScrubWorkerCommand::Resume => {
self.work = match std::mem::take(&mut self.work) {
ScrubWorkerState::Paused(it, _) => ScrubWorkerState::Running(it),
work => {
error!("Cannot resume scrub worker: not paused!");
work
}
};
}
ScrubWorkerCommand::Cancel => {
self.work = match std::mem::take(&mut self.work) {
ScrubWorkerState::Running(_) | ScrubWorkerState::Paused(_, _) => {
ScrubWorkerState::Finished
}
work => {
error!("Cannot cancel scrub worker: not running!");
work
}
}
}
ScrubWorkerCommand::SetTranquility(t) => {
self.persisted.tranquility = t;
if let Err(e) = self.persister.save_async(&self.persisted).await {
error!("Could not save new tranquilitiy value: {}", e);
}
}
}
}
}
#[async_trait]
impl Worker for ScrubWorker {
fn name(&self) -> String {
"Block scrub worker".into()
}
fn info(&self) -> Option<String> {
let s = match &self.work {
ScrubWorkerState::Running(bsi) => format!(
"{:.2}% done (tranquility = {})",
bsi.progress() * 100.,
self.persisted.tranquility
),
ScrubWorkerState::Paused(bsi, rt) => {
format!(
"Paused, {:.2}% done, resumes at {}",
bsi.progress() * 100.,
msec_to_rfc3339(*rt)
)
}
ScrubWorkerState::Finished => format!(
"Last completed scrub: {}",
msec_to_rfc3339(self.persisted.time_last_complete_scrub)
),
};
Some(format!(
"{} ; corruptions detected: {}",
s, self.persisted.corruptions_detected
))
}
async fn work(&mut self, _must_exit: &mut watch::Receiver<bool>) -> Result<WorkerState, Error> {
match self.rx_cmd.try_recv() {
Ok(cmd) => self.handle_cmd(cmd).await,
Err(mpsc::error::TryRecvError::Disconnected) => return Ok(WorkerState::Done),
Err(mpsc::error::TryRecvError::Empty) => (),
};
match &mut self.work {
ScrubWorkerState::Running(bsi) => {
self.tranquilizer.reset();
if let Some(hash) = bsi.next().await? {
match self.manager.read_block(&hash).await {
Err(Error::CorruptData(_)) => {
error!("Found corrupt data block during scrub: {:?}", hash);
self.persisted.corruptions_detected += 1;
self.persister.save_async(&self.persisted).await?;
}
Err(e) => return Err(e),
_ => (),
};
Ok(self
.tranquilizer
.tranquilize_worker(self.persisted.tranquility))
} else {
self.persisted.time_last_complete_scrub = now_msec();
self.persister.save_async(&self.persisted).await?;
self.work = ScrubWorkerState::Finished;
self.tranquilizer.clear();
Ok(WorkerState::Idle)
}
}
_ => Ok(WorkerState::Idle),
}
}
async fn wait_for_work(&mut self, _must_exit: &watch::Receiver<bool>) -> WorkerState {
let (wait_until, command) = match &self.work {
ScrubWorkerState::Running(_) => return WorkerState::Busy,
ScrubWorkerState::Paused(_, resume_time) => (*resume_time, ScrubWorkerCommand::Resume),
ScrubWorkerState::Finished => (
self.persisted.time_last_complete_scrub + SCRUB_INTERVAL.as_millis() as u64,
ScrubWorkerCommand::Start,
),
};
let now = now_msec();
if now >= wait_until {
self.handle_cmd(command).await;
return WorkerState::Busy;
}
let delay = Duration::from_millis(wait_until - now);
select! {
_ = tokio::time::sleep(delay) => self.handle_cmd(command).await,
cmd = self.rx_cmd.recv() => if let Some(cmd) = cmd {
self.handle_cmd(cmd).await;
} else {
return WorkerState::Done;
}
}
match &self.work {
ScrubWorkerState::Running(_) => WorkerState::Busy,
_ => WorkerState::Idle,
}
}
}
// ---- ---- ----
// UTILITY FOR ENUMERATING THE BLOCK STORE
// ---- ---- ----
struct BlockStoreIterator {
path: Vec<ReadingDir>,
}
enum ReadingDir {
Pending(PathBuf),
Read {
subpaths: Vec<fs::DirEntry>,
pos: usize,
},
}
impl BlockStoreIterator {
fn new(manager: &BlockManager) -> Self {
let root_dir = manager.data_dir.clone();
Self {
path: vec![ReadingDir::Pending(root_dir)],
}
}
/// Returns progress done, between 0 and 1
fn progress(&self) -> f32 {
if self.path.is_empty() {
1.0
} else {
let mut ret = 0.0;
let mut next_div = 1;
for p in self.path.iter() {
match p {
ReadingDir::Pending(_) => break,
ReadingDir::Read { subpaths, pos } => {
next_div *= subpaths.len();
ret += ((*pos - 1) as f32) / (next_div as f32);
}
}
}
ret
}
}
async fn next(&mut self) -> Result<Option<Hash>, Error> {
loop {
let last_path = match self.path.last_mut() {
None => return Ok(None),
Some(lp) => lp,
};
if let ReadingDir::Pending(path) = last_path {
let mut reader = fs::read_dir(&path).await?;
let mut subpaths = vec![];
while let Some(ent) = reader.next_entry().await? {
subpaths.push(ent);
}
*last_path = ReadingDir::Read { subpaths, pos: 0 };
}
let (subpaths, pos) = match *last_path {
ReadingDir::Read {
ref subpaths,
ref mut pos,
} => (subpaths, pos),
ReadingDir::Pending(_) => unreachable!(),
};
let data_dir_ent = match subpaths.get(*pos) {
None => {
self.path.pop();
continue;
}
Some(ent) => {
*pos += 1;
ent
}
};
let name = data_dir_ent.file_name();
let name = if let Ok(n) = name.into_string() {
n
} else {
continue;
};
let ent_type = data_dir_ent.file_type().await?;
let name = name.strip_suffix(".zst").unwrap_or(&name);
if name.len() == 2 && hex::decode(&name).is_ok() && ent_type.is_dir() {
let path = data_dir_ent.path();
self.path.push(ReadingDir::Pending(path));
} else if name.len() == 64 {
if let Ok(h) = hex::decode(&name) {
let mut hash = [0u8; 32];
hash.copy_from_slice(&h);
return Ok(Some(hash.into()));
}
}
}
}
}