block manager: scrub checkpointing

src/block/repair.rs

@@ -176,7 +176,9 @@ mod v081 {
 }
 
 mod v082 {
+	use garage_util::data::Hash;
 	use serde::{Deserialize, Serialize};
+	use std::path::PathBuf;
 
 	use super::v081;
 
@@ -186,6 +188,27 @@ mod v082 {
 		pub(crate) time_last_complete_scrub: u64,
 		pub(crate) time_next_run_scrub: u64,
 		pub(crate) corruptions_detected: u64,
+		#[serde(default)]
+		pub(crate) checkpoint: Option<BlockStoreIterator>,
+	}
+
+	#[derive(Serialize, Deserialize, Clone)]
+	pub struct BlockStoreIterator {
+		pub todo: Vec<BsiTodo>,
+	}
+
+	#[derive(Serialize, Deserialize, Clone)]
+	pub enum BsiTodo {
+		Directory {
+			path: PathBuf,
+			progress_min: u64,
+			progress_max: u64,
+		},
+		File {
+			path: PathBuf,
+			hash: Hash,
+			progress: u64,
+		},
 	}
 
 	impl garage_util::migrate::Migrate for ScrubWorkerPersisted {
@@ -200,6 +223,7 @@ mod v082 {
 				time_last_complete_scrub: old.time_last_complete_scrub,
 				time_next_run_scrub: randomize_next_scrub_run_time(old.time_last_complete_scrub),
 				corruptions_detected: old.corruptions_detected,
+				checkpoint: None,
 			}
 		}
 	}
@@ -236,14 +260,23 @@ impl Default for ScrubWorkerPersisted {
 			time_next_run_scrub: randomize_next_scrub_run_time(now_msec()),
 			tranquility: INITIAL_SCRUB_TRANQUILITY,
 			corruptions_detected: 0,
+			checkpoint: None,
 		}
 	}
 }
 
 #[derive(Default)]
 enum ScrubWorkerState {
-	Running(BlockStoreIterator),
-	Paused(BlockStoreIterator, u64), // u64 = time when to resume scrub
+	Running {
+		iterator: BlockStoreIterator,
+		// time of the last checkpoint
+		t_cp: u64,
+	},
+	Paused {
+		iterator: BlockStoreIterator,
+		// time at which the scrub should be resumed
+		t_resume: u64,
+	},
 	#[default]
 	Finished,
 }
@@ -262,10 +295,17 @@ impl ScrubWorker {
 		rx_cmd: mpsc::Receiver<ScrubWorkerCommand>,
 		persister: PersisterShared<ScrubWorkerPersisted>,
 	) -> Self {
+		let work = match persister.get_with(|x| x.checkpoint.clone()) {
+			None => ScrubWorkerState::Finished,
+			Some(iterator) => ScrubWorkerState::Running {
+				iterator,
+				t_cp: now_msec(),
+			},
+		};
 		Self {
 			manager,
 			rx_cmd,
-			work: ScrubWorkerState::Finished,
+			work,
 			tranquilizer: Tranquilizer::new(30),
 			persister,
 		}
@@ -278,7 +318,16 @@ impl ScrubWorker {
 					ScrubWorkerState::Finished => {
 						info!("Scrub worker initializing, now performing datastore scrub");
 						let iterator = BlockStoreIterator::new(&self.manager);
-						ScrubWorkerState::Running(iterator)
+						if let Err(e) = self
+							.persister
+							.set_with(|x| x.checkpoint = Some(iterator.clone()))
+						{
+							error!("Could not save scrub checkpoint: {}", e);
+						}
+						ScrubWorkerState::Running {
+							iterator,
+							t_cp: now_msec(),
+						}
 					}
 					work => {
 						error!("Cannot start scrub worker: already running!");
@@ -288,8 +337,18 @@ impl ScrubWorker {
 			}
 			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)
+					ScrubWorkerState::Running { iterator, .. }
+					| ScrubWorkerState::Paused { iterator, .. } => {
+						if let Err(e) = self
+							.persister
+							.set_with(|x| x.checkpoint = Some(iterator.clone()))
+						{
+							error!("Could not save scrub checkpoint: {}", e);
+						}
+						ScrubWorkerState::Paused {
+							iterator,
+							t_resume: now_msec() + dur.as_millis() as u64,
+						}
 					}
 					work => {
 						error!("Cannot pause scrub worker: not running!");
@@ -299,7 +358,10 @@ impl ScrubWorker {
 			}
 			ScrubWorkerCommand::Resume => {
 				self.work = match std::mem::take(&mut self.work) {
-					ScrubWorkerState::Paused(it, _) => ScrubWorkerState::Running(it),
+					ScrubWorkerState::Paused { iterator, .. } => ScrubWorkerState::Running {
+						iterator,
+						t_cp: now_msec(),
+					},
 					work => {
 						error!("Cannot resume scrub worker: not paused!");
 						work
@@ -308,7 +370,7 @@ impl ScrubWorker {
 			}
 			ScrubWorkerCommand::Cancel => {
 				self.work = match std::mem::take(&mut self.work) {
-					ScrubWorkerState::Running(_) | ScrubWorkerState::Paused(_, _) => {
+					ScrubWorkerState::Running { .. } | ScrubWorkerState::Paused { .. } => {
 						ScrubWorkerState::Finished
 					}
 					work => {
@@ -344,12 +406,15 @@ impl Worker for ScrubWorker {
 			..Default::default()
 		};
 		match &self.work {
-			ScrubWorkerState::Running(bsi) => {
-				s.progress = Some(format!("{:.2}%", bsi.progress() * 100.));
+			ScrubWorkerState::Running { iterator, .. } => {
+				s.progress = Some(format!("{:.2}%", iterator.progress() * 100.));
 			}
-			ScrubWorkerState::Paused(bsi, rt) => {
-				s.progress = Some(format!("{:.2}%", bsi.progress() * 100.));
-				s.freeform = vec![format!("Scrub paused, resumes at {}", msec_to_rfc3339(*rt))];
+			ScrubWorkerState::Paused { iterator, t_resume } => {
+				s.progress = Some(format!("{:.2}%", iterator.progress() * 100.));
+				s.freeform = vec![format!(
+					"Scrub paused, resumes at {}",
+					msec_to_rfc3339(*t_resume)
+				)];
 			}
 			ScrubWorkerState::Finished => {
 				s.freeform = vec![
@@ -375,9 +440,11 @@ impl Worker for ScrubWorker {
 		};
 
 		match &mut self.work {
-			ScrubWorkerState::Running(bsi) => {
+			ScrubWorkerState::Running { iterator, t_cp } => {
 				self.tranquilizer.reset();
-				if let Some((_path, hash)) = bsi.next().await? {
+				let now = now_msec();
+
+				if let Some((_path, hash)) = iterator.next().await? {
 					match self.manager.read_block(&hash).await {
 						Err(Error::CorruptData(_)) => {
 							error!("Found corrupt data block during scrub: {:?}", hash);
@@ -386,16 +453,23 @@ impl Worker for ScrubWorker {
 						Err(e) => return Err(e),
 						_ => (),
 					};
+
+					if now - *t_cp > 60 * 1000 {
+						self.persister
+							.set_with(|p| p.checkpoint = Some(iterator.clone()))?;
+						*t_cp = now;
+					}
+
 					Ok(self
 						.tranquilizer
 						.tranquilize_worker(self.persister.get_with(|p| p.tranquility)))
 				} else {
-					let now = now_msec();
 					let next_scrub_timestamp = randomize_next_scrub_run_time(now);
 
 					self.persister.set_with(|p| {
 						p.time_last_complete_scrub = now;
 						p.time_next_run_scrub = next_scrub_timestamp;
+						p.checkpoint = None;
 					})?;
 					self.work = ScrubWorkerState::Finished;
 					self.tranquilizer.clear();
@@ -414,8 +488,8 @@ impl Worker for ScrubWorker {
 
 	async fn wait_for_work(&mut self) -> WorkerState {
 		let (wait_until, command) = match &self.work {
-			ScrubWorkerState::Running(_) => return WorkerState::Busy,
-			ScrubWorkerState::Paused(_, resume_time) => (*resume_time, ScrubWorkerCommand::Resume),
+			ScrubWorkerState::Running { .. } => return WorkerState::Busy,
+			ScrubWorkerState::Paused { t_resume, .. } => (*t_resume, ScrubWorkerCommand::Resume),
 			ScrubWorkerState::Finished => (
 				self.persister.get_with(|p| p.time_next_run_scrub),
 				ScrubWorkerCommand::Start,
@@ -438,7 +512,7 @@ impl Worker for ScrubWorker {
 		}
 
 		match &self.work {
-			ScrubWorkerState::Running(_) => WorkerState::Busy,
+			ScrubWorkerState::Running { .. } => WorkerState::Busy,
 			_ => WorkerState::Idle,
 		}
 	}
@@ -450,23 +524,6 @@ impl Worker for ScrubWorker {
 
 const PROGRESS_FP: u64 = 1_000_000_000;
 
-struct BlockStoreIterator {
-	todo: Vec<BsiTodo>,
-}
-
-enum BsiTodo {
-	Directory {
-		path: PathBuf,
-		progress_min: u64,
-		progress_max: u64,
-	},
-	File {
-		path: PathBuf,
-		filename: String,
-		progress: u64,
-	},
-}
-
 impl BlockStoreIterator {
 	fn new(manager: &BlockManager) -> Self {
 		let min_cap = manager
@@ -551,11 +608,18 @@ impl BlockStoreIterator {
 								progress_max: 0,
 							});
 						} else if ft.is_file() {
-							self.todo.push(BsiTodo::File {
-								path: ent.path(),
-								filename: name,
-								progress: 0,
-							});
+							let filename = name.split_once('.').map(|(f, _)| f).unwrap_or(&name);
+							if filename.len() == 64 {
+								if let Ok(h) = hex::decode(filename) {
+									let mut hash = [0u8; 32];
+									hash.copy_from_slice(&h);
+									self.todo.push(BsiTodo::File {
+										path: ent.path(),
+										hash: hash.into(),
+										progress: 0,
+									});
+								}
+							}
 						}
 					}
 
@@ -582,20 +646,14 @@ impl BlockStoreIterator {
 					self.todo[istart..].reverse();
 					debug_assert!(self.progress_invariant());
 				}
-				Some(BsiTodo::File { path, filename, .. }) => {
-					let filename = filename.strip_suffix(".zst").unwrap_or(&filename);
-					if filename.len() == 64 {
-						if let Ok(h) = hex::decode(filename) {
-							let mut hash = [0u8; 32];
-							hash.copy_from_slice(&h);
-							return Ok(Some((path, hash.into())));
-						}
-					}
+				Some(BsiTodo::File { path, hash, .. }) => {
+					return Ok(Some((path, hash)));
 				}
 			}
 		}
 	}
 
+	// for debug_assert!
 	fn progress_invariant(&self) -> bool {
 		let iter = self.todo.iter().map(|x| match x {
 			BsiTodo::Directory { progress_min, .. } => progress_min,