doc/book/operations/durability-repairs.md

@@ -141,7 +141,4 @@ blocks may still be held by Garage. If you suspect that such corruption has occu
 in your cluster, you can run one of the following repair procedures:
 
 - `garage repair versions`: checks that all versions belong to a non-deleted object, and purges any orphan version
-
-- `garage repair block-refs`: checks that all block references belong to a non-deleted object version, and purges any orphan block reference (this will then allow the blocks to be garbage-collected)
-
-- `garage repair block-rc`: checks that the reference counters for blocks are in sync with the actual number of non-deleted entries in the block reference table
+- `garage repair block_refs`: checks that all block references belong to a non-deleted object version, and purges any orphan block reference (this will then allow the blocks to be garbage-collected)

src/block/lib.rs

@@ -11,4 +11,3 @@ mod metrics;
 mod rc;
 
 pub use block::zstd_encode;
-pub use rc::CalculateRefcount;

src/block/manager.rs

@@ -88,7 +88,7 @@ pub struct BlockManager {
 
 	mutation_lock: Vec<Mutex<BlockManagerLocked>>,
 
-	pub rc: BlockRc,
+	pub(crate) rc: BlockRc,
 	pub resync: BlockResyncManager,
 
 	pub(crate) system: Arc<System>,
@@ -156,7 +156,7 @@ impl BlockManager {
 
 		let metrics = BlockManagerMetrics::new(
 			config.compression_level,
-			rc.rc_table.clone(),
+			rc.rc.clone(),
 			resync.queue.clone(),
 			resync.errors.clone(),
 		);
@@ -229,12 +229,6 @@ impl BlockManager {
 		}
 	}
 
-	/// Initialization: set how block references are recalculated
-	/// for repair operations
-	pub fn set_recalc_rc(&self, recalc: Vec<CalculateRefcount>) {
-		self.rc.recalc_rc.store(Some(Arc::new(recalc)));
-	}
-
 	/// Ask nodes that might have a (possibly compressed) block for it
 	/// Return it as a stream with a header
 	async fn rpc_get_raw_block_streaming(
@@ -322,9 +316,9 @@ impl BlockManager {
 			};
 		}
 
-		let err = Error::MissingBlock(*hash);
-		debug!("{}", err);
-		Err(err)
+		let msg = format!("Get block {:?}: no node returned a valid block", hash);
+		debug!("{}", msg);
+		Err(Error::Message(msg))
 	}
 
 	// ---- Public interface ----
@@ -387,7 +381,7 @@ impl BlockManager {
 
 	/// Get number of items in the refcount table
 	pub fn rc_len(&self) -> Result<usize, Error> {
-		Ok(self.rc.rc_table.len()?)
+		Ok(self.rc.rc.len()?)
 	}
 
 	/// Send command to start/stop/manager scrub worker

src/block/rc.rs

@@ -1,7 +1,5 @@
 use std::convert::TryInto;
 
-use arc_swap::ArcSwapOption;
-
 use garage_db as db;
 
 use garage_util::data::*;
@@ -10,20 +8,13 @@ use garage_util::time::*;
 
 use crate::manager::BLOCK_GC_DELAY;
 
-pub type CalculateRefcount =
-	Box<dyn Fn(&db::Transaction, &Hash) -> db::TxResult<usize, Error> + Send + Sync>;
-
 pub struct BlockRc {
-	pub rc_table: db::Tree,
-	pub(crate) recalc_rc: ArcSwapOption<Vec<CalculateRefcount>>,
+	pub(crate) rc: db::Tree,
 }
 
 impl BlockRc {
 	pub(crate) fn new(rc: db::Tree) -> Self {
-		Self {
-			rc_table: rc,
-			recalc_rc: ArcSwapOption::new(None),
-		}
+		Self { rc }
 	}
 
 	/// Increment the reference counter associated to a hash.
@@ -33,9 +24,9 @@ impl BlockRc {
 		tx: &mut db::Transaction,
 		hash: &Hash,
 	) -> db::TxOpResult<bool> {
-		let old_rc = RcEntry::parse_opt(tx.get(&self.rc_table, hash)?);
+		let old_rc = RcEntry::parse_opt(tx.get(&self.rc, hash)?);
 		match old_rc.increment().serialize() {
-			Some(x) => tx.insert(&self.rc_table, hash, x)?,
+			Some(x) => tx.insert(&self.rc, hash, x)?,
 			None => unreachable!(),
 		};
 		Ok(old_rc.is_zero())
@@ -48,28 +39,28 @@ impl BlockRc {
 		tx: &mut db::Transaction,
 		hash: &Hash,
 	) -> db::TxOpResult<bool> {
-		let new_rc = RcEntry::parse_opt(tx.get(&self.rc_table, hash)?).decrement();
+		let new_rc = RcEntry::parse_opt(tx.get(&self.rc, hash)?).decrement();
 		match new_rc.serialize() {
-			Some(x) => tx.insert(&self.rc_table, hash, x)?,
-			None => tx.remove(&self.rc_table, hash)?,
+			Some(x) => tx.insert(&self.rc, hash, x)?,
+			None => tx.remove(&self.rc, hash)?,
 		};
 		Ok(matches!(new_rc, RcEntry::Deletable { .. }))
 	}
 
 	/// Read a block's reference count
 	pub(crate) fn get_block_rc(&self, hash: &Hash) -> Result<RcEntry, Error> {
-		Ok(RcEntry::parse_opt(self.rc_table.get(hash.as_ref())?))
+		Ok(RcEntry::parse_opt(self.rc.get(hash.as_ref())?))
 	}
 
 	/// Delete an entry in the RC table if it is deletable and the
 	/// deletion time has passed
 	pub(crate) fn clear_deleted_block_rc(&self, hash: &Hash) -> Result<(), Error> {
 		let now = now_msec();
-		self.rc_table.db().transaction(|tx| {
-			let rcval = RcEntry::parse_opt(tx.get(&self.rc_table, hash)?);
+		self.rc.db().transaction(|tx| {
+			let rcval = RcEntry::parse_opt(tx.get(&self.rc, hash)?);
 			match rcval {
 				RcEntry::Deletable { at_time } if now > at_time => {
-					tx.remove(&self.rc_table, hash)?;
+					tx.remove(&self.rc, hash)?;
 				}
 				_ => (),
 			};
@@ -77,58 +68,6 @@ impl BlockRc {
 		})?;
 		Ok(())
 	}
-
-	/// Recalculate the reference counter of a block
-	/// to fix potential inconsistencies
-	pub fn recalculate_rc(&self, hash: &Hash) -> Result<(usize, bool), Error> {
-		if let Some(recalc_fns) = self.recalc_rc.load().as_ref() {
-			trace!("Repair block RC for {:?}", hash);
-			let res = self
-				.rc_table
-				.db()
-				.transaction(|tx| {
-					let mut cnt = 0;
-					for f in recalc_fns.iter() {
-						cnt += f(&tx, hash)?;
-					}
-					let old_rc = RcEntry::parse_opt(tx.get(&self.rc_table, hash)?);
-					trace!(
-						"Block RC for {:?}: stored={}, calculated={}",
-						hash,
-						old_rc.as_u64(),
-						cnt
-					);
-					if cnt as u64 != old_rc.as_u64() {
-						warn!(
-							"Fixing inconsistent block RC for {:?}: was {}, should be {}",
-							hash,
-							old_rc.as_u64(),
-							cnt
-						);
-						let new_rc = if cnt > 0 {
-							RcEntry::Present { count: cnt as u64 }
-						} else {
-							RcEntry::Deletable {
-								at_time: now_msec() + BLOCK_GC_DELAY.as_millis() as u64,
-							}
-						};
-						tx.insert(&self.rc_table, hash, new_rc.serialize().unwrap())?;
-						Ok((cnt, true))
-					} else {
-						Ok((cnt, false))
-					}
-				})
-				.map_err(Error::from);
-			if let Err(e) = &res {
-				error!("Failed to fix RC for block {:?}: {}", hash, e);
-			}
-			res
-		} else {
-			Err(Error::Message(
-				"Block RC recalculation is not available at this point".into(),
-			))
-		}
-	}
 }
 
 /// Describes the state of the reference counter for a block

src/block/repair.rs

@@ -107,7 +107,7 @@ impl Worker for RepairWorker {
 				for entry in self
 					.manager
 					.rc
-					.rc_table
+					.rc
 					.range::<&[u8], _>((start_bound, Bound::Unbounded))?
 				{
 					let (hash, _) = entry?;

src/block/resync.rs

@@ -367,13 +367,6 @@ impl BlockResyncManager {
 		}
 
 		if exists && rc.is_deletable() {
-			if manager.rc.recalculate_rc(hash)?.0 > 0 {
-				return Err(Error::Message(format!(
-					"Refcount for block {:?} was inconsistent, retrying later",
-					hash
-				)));
-			}
-
 			info!("Resync block {:?}: offloading and deleting", hash);
 			let existing_path = existing_path.unwrap();
 
@@ -460,15 +453,7 @@ impl BlockResyncManager {
 				hash
 			);
 
-			let block_data = manager.rpc_get_raw_block(hash, None).await;
-			if matches!(block_data, Err(Error::MissingBlock(_))) {
-				warn!(
-					"Could not fetch needed block {:?}, no node returned valid data. Checking that refcount is correct.",
-					hash
-				);
-				manager.rc.recalculate_rc(hash)?;
-			}
-			let block_data = block_data?;
+			let block_data = manager.rpc_get_raw_block(hash, None).await?;
 
 			manager.metrics.resync_recv_counter.add(1);
 

src/garage/cli/structs.rs

@@ -473,11 +473,8 @@ pub enum RepairWhat {
 	#[structopt(name = "mpu", version = garage_version())]
 	MultipartUploads,
 	/// Repropagate version deletions to the block ref table
-	#[structopt(name = "block-refs", version = garage_version())]
+	#[structopt(name = "block_refs", version = garage_version())]
 	BlockRefs,
-	/// Recalculate block reference counters
-	#[structopt(name = "block-rc", version = garage_version())]
-	BlockRc,
 	/// Verify integrity of all blocks on disc
 	#[structopt(name = "scrub", version = garage_version())]
 	Scrub {

src/garage/cli/util.rs

@@ -451,7 +451,7 @@ pub fn print_block_info(
 	if refcount != nondeleted_count {
 		println!();
 		println!(
-			"Warning: refcount does not match number of non-deleted versions, you should try `garage repair block-rc`."
+			"Warning: refcount does not match number of non-deleted versions (see issue #644)."
 		);
 	}
 }

src/garage/repair/online.rs

@@ -4,7 +4,6 @@ use std::time::Duration;
 use async_trait::async_trait;
 use tokio::sync::watch;
 
-use garage_block::manager::BlockManager;
 use garage_block::repair::ScrubWorkerCommand;
 
 use garage_model::garage::Garage;
@@ -17,14 +16,11 @@ use garage_table::replication::*;
 use garage_table::*;
 
 use garage_util::background::*;
-use garage_util::data::*;
 use garage_util::error::Error;
 use garage_util::migrate::Migrate;
 
 use crate::*;
 
-const RC_REPAIR_ITER_COUNT: usize = 64;
-
 pub async fn launch_online_repair(
 	garage: &Arc<Garage>,
 	bg: &BackgroundRunner,
@@ -51,13 +47,6 @@ pub async fn launch_online_repair(
 			info!("Repairing the block refs table");
 			bg.spawn_worker(TableRepairWorker::new(garage.clone(), RepairBlockRefs));
 		}
-		RepairWhat::BlockRc => {
-			info!("Repairing the block reference counters");
-			bg.spawn_worker(BlockRcRepair::new(
-				garage.block_manager.clone(),
-				garage.block_ref_table.clone(),
-			));
-		}
 		RepairWhat::Blocks => {
 			info!("Repairing the stored blocks");
 			bg.spawn_worker(garage_block::repair::RepairWorker::new(
@@ -293,98 +282,3 @@ impl TableRepair for RepairMpu {
 		Ok(false)
 	}
 }
-
-// ===== block reference counter repair =====
-
-pub struct BlockRcRepair {
-	block_manager: Arc<BlockManager>,
-	block_ref_table: Arc<Table<BlockRefTable, TableShardedReplication>>,
-	cursor: Hash,
-	counter: u64,
-	repairs: u64,
-}
-
-impl BlockRcRepair {
-	fn new(
-		block_manager: Arc<BlockManager>,
-		block_ref_table: Arc<Table<BlockRefTable, TableShardedReplication>>,
-	) -> Self {
-		Self {
-			block_manager,
-			block_ref_table,
-			cursor: [0u8; 32].into(),
-			counter: 0,
-			repairs: 0,
-		}
-	}
-}
-
-#[async_trait]
-impl Worker for BlockRcRepair {
-	fn name(&self) -> String {
-		format!("Block refcount repair worker")
-	}
-
-	fn status(&self) -> WorkerStatus {
-		WorkerStatus {
-			progress: Some(format!("{} ({})", self.counter, self.repairs)),
-			..Default::default()
-		}
-	}
-
-	async fn work(&mut self, _must_exit: &mut watch::Receiver<bool>) -> Result<WorkerState, Error> {
-		for _i in 0..RC_REPAIR_ITER_COUNT {
-			let next1 = self
-				.block_manager
-				.rc
-				.rc_table
-				.range(self.cursor.as_slice()..)?
-				.next()
-				.transpose()?
-				.map(|(k, _)| Hash::try_from(k.as_slice()).unwrap());
-			let next2 = self
-				.block_ref_table
-				.data
-				.store
-				.range(self.cursor.as_slice()..)?
-				.next()
-				.transpose()?
-				.map(|(k, _)| Hash::try_from(&k[..32]).unwrap());
-			let next = match (next1, next2) {
-				(Some(k1), Some(k2)) => std::cmp::min(k1, k2),
-				(Some(k), None) | (None, Some(k)) => k,
-				(None, None) => {
-					info!(
-						"{}: finished, done {}, fixed {}",
-						self.name(),
-						self.counter,
-						self.repairs
-					);
-					return Ok(WorkerState::Done);
-				}
-			};
-
-			if self.block_manager.rc.recalculate_rc(&next)?.1 {
-				self.repairs += 1;
-			}
-			self.counter += 1;
-			if let Some(next_incr) = next.increment() {
-				self.cursor = next_incr;
-			} else {
-				info!(
-					"{}: finished, done {}, fixed {}",
-					self.name(),
-					self.counter,
-					self.repairs
-				);
-				return Ok(WorkerState::Done);
-			}
-		}
-
-		Ok(WorkerState::Busy)
-	}
-
-	async fn wait_for_work(&mut self) -> WorkerState {
-		unreachable!()
-	}
-}

src/model/garage.rs

@@ -247,14 +247,6 @@ impl Garage {
 		#[cfg(feature = "k2v")]
 		let k2v = GarageK2V::new(system.clone(), &db, meta_rep_param);
 
-		// ---- setup block refcount recalculation ----
-		// this function can be used to fix inconsistencies in the RC table
-		block_manager.set_recalc_rc(vec![
-			block_ref_recount_fn(&block_ref_table),
-			// other functions could be added here if we had other tables
-			// that hold references to data blocks
-		]);
-
 		// -- done --
 		Ok(Arc::new(Self {
 			config,

src/model/s3/block_ref_table.rs

@@ -3,12 +3,8 @@ use std::sync::Arc;
 use garage_db as db;
 
 use garage_util::data::*;
-use garage_util::error::*;
-use garage_util::migrate::Migrate;
 
-use garage_block::CalculateRefcount;
 use garage_table::crdt::Crdt;
-use garage_table::replication::TableShardedReplication;
 use garage_table::*;
 
 use garage_block::manager::*;
@@ -88,38 +84,3 @@ impl TableSchema for BlockRefTable {
 		filter.apply(entry.deleted.get())
 	}
 }
-
-pub fn block_ref_recount_fn(
-	block_ref_table: &Arc<Table<BlockRefTable, TableShardedReplication>>,
-) -> CalculateRefcount {
-	let table = Arc::downgrade(block_ref_table);
-	Box::new(move |tx: &db::Transaction, block: &Hash| {
-		let table = table
-			.upgrade()
-			.ok_or_message("cannot upgrade weak ptr to block_ref_table")
-			.map_err(db::TxError::Abort)?;
-		Ok(calculate_refcount(&table, tx, block)?)
-	})
-}
-
-fn calculate_refcount(
-	block_ref_table: &Table<BlockRefTable, TableShardedReplication>,
-	tx: &db::Transaction,
-	block: &Hash,
-) -> db::TxResult<usize, Error> {
-	let mut result = 0;
-	for entry in tx.range(&block_ref_table.data.store, block.as_slice()..)? {
-		let (key, value) = entry?;
-		if &key[..32] != block.as_slice() {
-			break;
-		}
-		let value = BlockRef::decode(&value)
-			.ok_or_message("could not decode block_ref")
-			.map_err(db::TxError::Abort)?;
-		assert_eq!(value.block, *block);
-		if !value.deleted.get() {
-			result += 1;
-		}
-	}
-	Ok(result)
-}

src/util/data.rs

@@ -83,19 +83,6 @@ impl FixedBytes32 {
 		ret.copy_from_slice(by);
 		Some(Self(ret))
 	}
-	/// Return the next hash
-	pub fn increment(&self) -> Option<Self> {
-		let mut ret = *self;
-		for byte in ret.0.iter_mut().rev() {
-			if *byte == u8::MAX {
-				*byte = 0;
-			} else {
-				*byte = *byte + 1;
-				return Some(ret);
-			}
-		}
-		return None;
-	}
 }
 
 impl From<garage_net::NodeID> for FixedBytes32 {
@@ -153,25 +140,3 @@ pub fn fasthash(data: &[u8]) -> FastHash {
 pub fn gen_uuid() -> Uuid {
 	rand::thread_rng().gen::<[u8; 32]>().into()
 }
-
-#[cfg(test)]
-mod test {
-	use super::*;
-
-	#[test]
-	fn test_increment() {
-		let zero: FixedBytes32 = [0u8; 32].into();
-		let mut one: FixedBytes32 = [0u8; 32].into();
-		one.0[31] = 1;
-		let max: FixedBytes32 = [0xFFu8; 32].into();
-		assert_eq!(zero.increment(), Some(one));
-		assert_eq!(max.increment(), None);
-
-		let mut test: FixedBytes32 = [0u8; 32].into();
-		let i = 0x198DF97209F8FFFFu64;
-		test.0[24..32].copy_from_slice(&u64::to_be_bytes(i));
-		let mut test2: FixedBytes32 = [0u8; 32].into();
-		test2.0[24..32].copy_from_slice(&u64::to_be_bytes(i + 1));
-		assert_eq!(test.increment(), Some(test2));
-	}
-}

src/util/error.rs

@@ -70,9 +70,6 @@ pub enum Error {
 	#[error(display = "Corrupt data: does not match hash {:?}", _0)]
 	CorruptData(Hash),
 
-	#[error(display = "Missing block {:?}: no node returned a valid block", _0)]
-	MissingBlock(Hash),
-
 	#[error(display = "{}", _0)]
 	Message(String),
 }