diff options
Diffstat (limited to 'src/block')
| -rw-r--r-- | src/block/Cargo.toml | 18 | ||||
| -rw-r--r-- | src/block/block.rs | 48 | ||||
| -rw-r--r-- | src/block/lib.rs | 2 | ||||
| -rw-r--r-- | src/block/manager.rs | 941 | ||||
| -rw-r--r-- | src/block/metrics.rs | 4 | ||||
| -rw-r--r-- | src/block/rc.rs | 49 | ||||
| -rw-r--r-- | src/block/repair.rs | 466 | ||||
| -rw-r--r-- | src/block/resync.rs | 589 |
8 files changed, 1450 insertions, 667 deletions
diff --git a/src/block/Cargo.toml b/src/block/Cargo.toml index 9cba69ee..cd409001 100644 --- a/src/block/Cargo.toml +++ b/src/block/Cargo.toml @@ -1,6 +1,6 @@ [package] name = "garage_block" -version = "0.7.0" +version = "0.8.0" authors = ["Alex Auvolat <alex@adnab.me>"] edition = "2018" license = "AGPL-3.0" @@ -14,20 +14,22 @@ path = "lib.rs" # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html [dependencies] -garage_rpc = { version = "0.7.0", path = "../rpc" } -garage_util = { version = "0.7.0", path = "../util" } -garage_table = { version = "0.7.0", path = "../table" } +garage_db = { version = "0.8.0", path = "../db" } +garage_rpc = { version = "0.8.0", path = "../rpc" } +garage_util = { version = "0.8.0", path = "../util" } +garage_table = { version = "0.8.0", path = "../table" } opentelemetry = "0.17" +arc-swap = "1.5" async-trait = "0.1.7" bytes = "1.0" hex = "0.4" tracing = "0.1.30" rand = "0.8" -zstd = { version = "0.9", default-features = false } -sled = "0.34" +async-compression = { version = "0.3", features = ["tokio", "zstd"] } +zstd = { version = "0.9", default-features = false } rmp-serde = "0.15" serde = { version = "1.0", default-features = false, features = ["derive", "rc"] } @@ -36,3 +38,7 @@ serde_bytes = "0.11" futures = "0.3" futures-util = "0.3" tokio = { version = "1.0", default-features = false, features = ["rt", "rt-multi-thread", "io-util", "net", "time", "macros", "sync", "signal", "fs"] } +tokio-util = { version = "0.6", features = ["io"] } + +[features] +system-libs = [ "zstd/pkg-config" ] diff --git a/src/block/block.rs b/src/block/block.rs index 4d3fbcb8..935aa900 100644 --- a/src/block/block.rs +++ b/src/block/block.rs @@ -1,16 +1,22 @@ +use bytes::Bytes; use serde::{Deserialize, Serialize}; use zstd::stream::{decode_all as zstd_decode, Encoder}; use garage_util::data::*; use garage_util::error::*; +#[derive(Debug, Serialize, Deserialize, Copy, Clone)] +pub enum DataBlockHeader { + Plain, + Compressed, +} + /// A possibly compressed block of data -#[derive(Debug, Serialize, Deserialize)] pub enum DataBlock { /// Uncompressed data - Plain(#[serde(with = "serde_bytes")] Vec<u8>), + Plain(Bytes), /// Data compressed with zstd - Compressed(#[serde(with = "serde_bytes")] Vec<u8>), + Compressed(Bytes), } impl DataBlock { @@ -30,7 +36,7 @@ impl DataBlock { /// Get the buffer, possibly decompressing it, and verify it's integrity. /// For Plain block, data is compared to hash, for Compressed block, zstd checksumming system /// is used instead. - pub fn verify_get(self, hash: Hash) -> Result<Vec<u8>, Error> { + pub fn verify_get(self, hash: Hash) -> Result<Bytes, Error> { match self { DataBlock::Plain(data) => { if blake2sum(&data) == hash { @@ -39,9 +45,9 @@ impl DataBlock { Err(Error::CorruptData(hash)) } } - DataBlock::Compressed(data) => { - zstd_decode(&data[..]).map_err(|_| Error::CorruptData(hash)) - } + DataBlock::Compressed(data) => zstd_decode(&data[..]) + .map_err(|_| Error::CorruptData(hash)) + .map(Bytes::from), } } @@ -61,13 +67,31 @@ impl DataBlock { } } - pub fn from_buffer(data: Vec<u8>, level: Option<i32>) -> DataBlock { - if let Some(level) = level { - if let Ok(data) = zstd_encode(&data[..], level) { - return DataBlock::Compressed(data); + pub async fn from_buffer(data: Bytes, level: Option<i32>) -> DataBlock { + tokio::task::spawn_blocking(move || { + if let Some(level) = level { + if let Ok(data) = zstd_encode(&data[..], level) { + return DataBlock::Compressed(data.into()); + } } + DataBlock::Plain(data) + }) + .await + .unwrap() + } + + pub fn into_parts(self) -> (DataBlockHeader, Bytes) { + match self { + DataBlock::Plain(data) => (DataBlockHeader::Plain, data), + DataBlock::Compressed(data) => (DataBlockHeader::Compressed, data), + } + } + + pub fn from_parts(h: DataBlockHeader, bytes: Bytes) -> Self { + match h { + DataBlockHeader::Plain => DataBlock::Plain(bytes), + DataBlockHeader::Compressed => DataBlock::Compressed(bytes), } - DataBlock::Plain(data) } } diff --git a/src/block/lib.rs b/src/block/lib.rs index dc685657..d2814f77 100644 --- a/src/block/lib.rs +++ b/src/block/lib.rs @@ -2,6 +2,8 @@ extern crate tracing; pub mod manager; +pub mod repair; +pub mod resync; mod block; mod metrics; diff --git a/src/block/manager.rs b/src/block/manager.rs index 1c04a335..7f439b96 100644 --- a/src/block/manager.rs +++ b/src/block/manager.rs @@ -1,29 +1,32 @@ -use std::convert::TryInto; -use std::path::{Path, PathBuf}; +use std::path::PathBuf; +use std::pin::Pin; use std::sync::Arc; use std::time::Duration; use async_trait::async_trait; +use bytes::Bytes; use serde::{Deserialize, Serialize}; -use futures::future::*; -use futures::select; +use futures::Stream; +use futures_util::stream::StreamExt; use tokio::fs; -use tokio::io::{AsyncReadExt, AsyncWriteExt}; -use tokio::sync::{watch, Mutex, Notify}; +use tokio::io::{AsyncReadExt, AsyncWriteExt, BufReader}; +use tokio::sync::{mpsc, Mutex, MutexGuard}; use opentelemetry::{ trace::{FutureExt as OtelFutureExt, TraceContextExt, Tracer}, - Context, KeyValue, + Context, }; +use garage_rpc::rpc_helper::netapp::stream::{stream_asyncread, ByteStream}; + +use garage_db as db; + use garage_util::data::*; use garage_util::error::*; use garage_util::metrics::RecordDuration; -use garage_util::sled_counter::SledCountedTree; -use garage_util::time::*; -use garage_util::tranquilizer::Tranquilizer; +use garage_rpc::rpc_helper::OrderTag; use garage_rpc::system::System; use garage_rpc::*; @@ -32,24 +35,12 @@ use garage_table::replication::{TableReplication, TableShardedReplication}; use crate::block::*; use crate::metrics::*; use crate::rc::*; +use crate::repair::*; +use crate::resync::*; /// Size under which data will be stored inlined in database instead of as files pub const INLINE_THRESHOLD: usize = 3072; -// Timeout for RPCs that read and write blocks to remote nodes -const BLOCK_RW_TIMEOUT: Duration = Duration::from_secs(30); -// Timeout for RPCs that ask other nodes whether they need a copy -// of a given block before we delete it locally -const NEED_BLOCK_QUERY_TIMEOUT: Duration = Duration::from_secs(5); - -// The delay between the time where a resync operation fails -// and the time when it is retried, with exponential backoff -// (multiplied by 2, 4, 8, 16, etc. for every consecutive failure). -const RESYNC_RETRY_DELAY: Duration = Duration::from_secs(60); -// The minimum retry delay is 60 seconds = 1 minute -// The maximum retry delay is 60 seconds * 2^6 = 60 seconds << 6 = 64 minutes (~1 hour) -const RESYNC_RETRY_DELAY_MAX_BACKOFF_POWER: u64 = 6; - // The delay between the moment when the reference counter // drops to zero, and the moment where we allow ourselves // to delete the block locally. @@ -60,12 +51,12 @@ pub(crate) const BLOCK_GC_DELAY: Duration = Duration::from_secs(600); pub enum BlockRpc { Ok, /// Message to ask for a block of data, by hash - GetBlock(Hash), + GetBlock(Hash, Option<OrderTag>), /// Message to send a block of data, either because requested, of for first delivery of new /// block PutBlock { hash: Hash, - data: DataBlock, + header: DataBlockHeader, }, /// Ask other node if they should have this block, but don't actually have it NeedBlockQuery(Hash), @@ -85,20 +76,18 @@ pub struct BlockManager { pub data_dir: PathBuf, compression_level: Option<i32>, - background_tranquility: u32, - mutation_lock: Mutex<BlockManagerLocked>, + mutation_lock: [Mutex<BlockManagerLocked>; 256], - rc: BlockRc, + pub(crate) rc: BlockRc, + pub resync: BlockResyncManager, - resync_queue: SledCountedTree, - resync_notify: Notify, - resync_errors: SledCountedTree, + pub(crate) system: Arc<System>, + pub(crate) endpoint: Arc<Endpoint<BlockRpc, Self>>, - system: Arc<System>, - endpoint: Arc<Endpoint<BlockRpc, Self>>, + pub(crate) metrics: BlockManagerMetrics, - metrics: BlockManagerMetrics, + tx_scrub_command: mpsc::Sender<ScrubWorkerCommand>, } // This custom struct contains functions that must only be ran @@ -108,10 +97,9 @@ struct BlockManagerLocked(); impl BlockManager { pub fn new( - db: &sled::Db, + db: &db::Db, data_dir: PathBuf, compression_level: Option<i32>, - background_tranquility: u32, replication: TableShardedReplication, system: Arc<System>, ) -> Arc<Self> { @@ -120,215 +108,323 @@ impl BlockManager { .expect("Unable to open block_local_rc tree"); let rc = BlockRc::new(rc); - let resync_queue = db - .open_tree("block_local_resync_queue") - .expect("Unable to open block_local_resync_queue tree"); - let resync_queue = SledCountedTree::new(resync_queue); - - let resync_errors = db - .open_tree("block_local_resync_errors") - .expect("Unable to open block_local_resync_errors tree"); - let resync_errors = SledCountedTree::new(resync_errors); + let resync = BlockResyncManager::new(db, &system); let endpoint = system .netapp - .endpoint("garage_model/block.rs/Rpc".to_string()); + .endpoint("garage_block/manager.rs/Rpc".to_string()); - let manager_locked = BlockManagerLocked(); + let metrics = BlockManagerMetrics::new(resync.queue.clone(), resync.errors.clone()); - let metrics = BlockManagerMetrics::new(resync_queue.clone(), resync_errors.clone()); + let (scrub_tx, scrub_rx) = mpsc::channel(1); let block_manager = Arc::new(Self { replication, data_dir, compression_level, - background_tranquility, - mutation_lock: Mutex::new(manager_locked), + mutation_lock: [(); 256].map(|_| Mutex::new(BlockManagerLocked())), rc, - resync_queue, - resync_notify: Notify::new(), - resync_errors, + resync, system, endpoint, metrics, + tx_scrub_command: scrub_tx, }); block_manager.endpoint.set_handler(block_manager.clone()); - block_manager.clone().spawn_background_worker(); + // Spawn a bunch of resync workers + for index in 0..MAX_RESYNC_WORKERS { + let worker = ResyncWorker::new(index, block_manager.clone()); + block_manager.system.background.spawn_worker(worker); + } + + // Spawn scrub worker + let scrub_worker = ScrubWorker::new(block_manager.clone(), scrub_rx); + block_manager.system.background.spawn_worker(scrub_worker); block_manager } /// Ask nodes that might have a (possibly compressed) block for it - async fn rpc_get_raw_block(&self, hash: &Hash) -> Result<DataBlock, Error> { + /// Return it as a stream with a header + async fn rpc_get_raw_block_streaming( + &self, + hash: &Hash, + order_tag: Option<OrderTag>, + ) -> Result<(DataBlockHeader, ByteStream), Error> { let who = self.replication.read_nodes(hash); - let resps = self - .system - .rpc - .try_call_many( - &self.endpoint, - &who[..], - BlockRpc::GetBlock(*hash), - RequestStrategy::with_priority(PRIO_NORMAL) - .with_quorum(1) - .with_timeout(BLOCK_RW_TIMEOUT) - .interrupt_after_quorum(true), - ) - .await?; + let who = self.system.rpc.request_order(&who); + + for node in who.iter() { + let node_id = NodeID::from(*node); + let rpc = self.endpoint.call_streaming( + &node_id, + BlockRpc::GetBlock(*hash, order_tag), + PRIO_NORMAL | PRIO_SECONDARY, + ); + tokio::select! { + res = rpc => { + let res = match res { + Ok(res) => res, + Err(e) => { + debug!("Node {:?} returned error: {}", node, e); + continue; + } + }; + let (header, stream) = match res.into_parts() { + (Ok(BlockRpc::PutBlock { hash: _, header }), Some(stream)) => (header, stream), + _ => { + debug!("Node {:?} returned a malformed response", node); + continue; + } + }; + return Ok((header, stream)); + } + _ = tokio::time::sleep(self.system.rpc.rpc_timeout()) => { + debug!("Node {:?} didn't return block in time, trying next.", node); + } + }; + } - for resp in resps { - if let BlockRpc::PutBlock { data, .. } = resp { - return Ok(data); - } + Err(Error::Message(format!( + "Unable to read block {:?}: no node returned a valid block", + hash + ))) + } + + /// Ask nodes that might have a (possibly compressed) block for it + /// Return its entire body + pub(crate) async fn rpc_get_raw_block( + &self, + hash: &Hash, + order_tag: Option<OrderTag>, + ) -> Result<DataBlock, Error> { + let who = self.replication.read_nodes(hash); + let who = self.system.rpc.request_order(&who); + + for node in who.iter() { + let node_id = NodeID::from(*node); + let rpc = self.endpoint.call_streaming( + &node_id, + BlockRpc::GetBlock(*hash, order_tag), + PRIO_NORMAL | PRIO_SECONDARY, + ); + tokio::select! { + res = rpc => { + let res = match res { + Ok(res) => res, + Err(e) => { + debug!("Node {:?} returned error: {}", node, e); + continue; + } + }; + let (header, stream) = match res.into_parts() { + (Ok(BlockRpc::PutBlock { hash: _, header }), Some(stream)) => (header, stream), + _ => { + debug!("Node {:?} returned a malformed response", node); + continue; + } + }; + match read_stream_to_end(stream).await { + Ok(bytes) => return Ok(DataBlock::from_parts(header, bytes)), + Err(e) => { + debug!("Error reading stream from node {:?}: {}", node, e); + } + } + } + _ = tokio::time::sleep(self.system.rpc.rpc_timeout()) => { + debug!("Node {:?} didn't return block in time, trying next.", node); + } + }; } + Err(Error::Message(format!( - "Unable to read block {:?}: no valid blocks returned", + "Unable to read block {:?}: no node returned a valid block", hash ))) } // ---- Public interface ---- + /// Ask nodes that might have a block for it, + /// return it as a stream + pub async fn rpc_get_block_streaming( + &self, + hash: &Hash, + order_tag: Option<OrderTag>, + ) -> Result< + Pin<Box<dyn Stream<Item = Result<Bytes, std::io::Error>> + Send + Sync + 'static>>, + Error, + > { + let (header, stream) = self.rpc_get_raw_block_streaming(hash, order_tag).await?; + match header { + DataBlockHeader::Plain => Ok(stream), + DataBlockHeader::Compressed => { + // Too many things, I hate it. + let reader = stream_asyncread(stream); + let reader = BufReader::new(reader); + let reader = async_compression::tokio::bufread::ZstdDecoder::new(reader); + Ok(Box::pin(tokio_util::io::ReaderStream::new(reader))) + } + } + } + /// Ask nodes that might have a block for it - pub async fn rpc_get_block(&self, hash: &Hash) -> Result<Vec<u8>, Error> { - self.rpc_get_raw_block(hash).await?.verify_get(*hash) + pub async fn rpc_get_block( + &self, + hash: &Hash, + order_tag: Option<OrderTag>, + ) -> Result<Bytes, Error> { + self.rpc_get_raw_block(hash, order_tag) + .await? + .verify_get(*hash) } /// Send block to nodes that should have it - pub async fn rpc_put_block(&self, hash: Hash, data: Vec<u8>) -> Result<(), Error> { + pub async fn rpc_put_block(&self, hash: Hash, data: Bytes) -> Result<(), Error> { let who = self.replication.write_nodes(&hash); - let data = DataBlock::from_buffer(data, self.compression_level); + + let (header, bytes) = DataBlock::from_buffer(data, self.compression_level) + .await + .into_parts(); + let put_block_rpc = + Req::new(BlockRpc::PutBlock { hash, header })?.with_stream_from_buffer(bytes); + self.system .rpc .try_call_many( &self.endpoint, &who[..], - BlockRpc::PutBlock { hash, data }, - RequestStrategy::with_priority(PRIO_NORMAL) - .with_quorum(self.replication.write_quorum()) - .with_timeout(BLOCK_RW_TIMEOUT), + put_block_rpc, + RequestStrategy::with_priority(PRIO_NORMAL | PRIO_SECONDARY) + .with_quorum(self.replication.write_quorum()), ) .await?; - Ok(()) - } - /// Launch the repair procedure on the data store - /// - /// This will list all blocks locally present, as well as those - /// that are required because of refcount > 0, and will try - /// to fix any mismatch between the two. - pub async fn repair_data_store(&self, must_exit: &watch::Receiver<bool>) -> Result<(), Error> { - // 1. Repair blocks from RC table. - for (i, entry) in self.rc.rc.iter().enumerate() { - let (hash, _) = entry?; - let hash = Hash::try_from(&hash[..]).unwrap(); - self.put_to_resync(&hash, Duration::from_secs(0))?; - if i & 0xFF == 0 && *must_exit.borrow() { - return Ok(()); - } - } - - // 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. - self.for_each_file( - (), - move |_, hash| async move { - self.put_to_resync(&hash, Duration::from_secs(0)) - .map_err(Into::into) - }, - must_exit, - ) - .await - } - - /// Verify integrity of each block on disk. Use `speed_limit` to limit the load generated by - /// this function. - pub async fn scrub_data_store( - &self, - must_exit: &watch::Receiver<bool>, - tranquility: u32, - ) -> Result<(), Error> { - let tranquilizer = Tranquilizer::new(30); - self.for_each_file( - tranquilizer, - move |mut tranquilizer, hash| async move { - let _ = self.read_block(&hash).await; - tranquilizer.tranquilize(tranquility).await; - Ok(tranquilizer) - }, - must_exit, - ) - .await - } - - /// Get lenght of resync queue - pub fn resync_queue_len(&self) -> usize { - self.resync_queue.len() + Ok(()) } - /// Get number of blocks that have an error - pub fn resync_errors_len(&self) -> usize { - self.resync_errors.len() + /// Get number of items in the refcount table + pub fn rc_len(&self) -> Result<usize, Error> { + Ok(self.rc.rc.len()?) } - /// Get number of items in the refcount table - pub fn rc_len(&self) -> usize { - self.rc.rc.len() + /// Send command to start/stop/manager scrub worker + pub async fn send_scrub_command(&self, cmd: ScrubWorkerCommand) { + let _ = self.tx_scrub_command.send(cmd).await; } //// ----- Managing the reference counter ---- /// Increment the number of time a block is used, putting it to resynchronization if it is /// required, but not known - pub fn block_incref(&self, hash: &Hash) -> Result<(), Error> { - if self.rc.block_incref(hash)? { + pub fn block_incref( + self: &Arc<Self>, + tx: &mut db::Transaction, + hash: Hash, + ) -> db::TxOpResult<()> { + if self.rc.block_incref(tx, &hash)? { // When the reference counter is incremented, there is // normally a node that is responsible for sending us the // data of the block. However that operation may fail, // so in all cases we add the block here to the todo list // to check later that it arrived correctly, and if not // we will fecth it from someone. - self.put_to_resync(hash, 2 * BLOCK_RW_TIMEOUT)?; + let this = self.clone(); + tokio::spawn(async move { + if let Err(e) = this + .resync + .put_to_resync(&hash, 2 * this.system.rpc.rpc_timeout()) + { + error!("Block {:?} could not be put in resync queue: {}.", hash, e); + } + }); } Ok(()) } /// Decrement the number of time a block is used - pub fn block_decref(&self, hash: &Hash) -> Result<(), Error> { - if self.rc.block_decref(hash)? { + pub fn block_decref( + self: &Arc<Self>, + tx: &mut db::Transaction, + hash: Hash, + ) -> db::TxOpResult<()> { + if self.rc.block_decref(tx, &hash)? { // When the RC is decremented, it might drop to zero, // indicating that we don't need the block. // There is a delay before we garbage collect it; // make sure that it is handled in the resync loop // after that delay has passed. - self.put_to_resync(hash, BLOCK_GC_DELAY + Duration::from_secs(10))?; + let this = self.clone(); + tokio::spawn(async move { + if let Err(e) = this + .resync + .put_to_resync(&hash, BLOCK_GC_DELAY + Duration::from_secs(10)) + { + error!("Block {:?} could not be put in resync queue: {}.", hash, e); + } + }); } Ok(()) } // ---- Reading and writing blocks locally ---- + async fn handle_put_block( + &self, + hash: Hash, + header: DataBlockHeader, + stream: Option<ByteStream>, + ) -> Result<(), Error> { + let stream = stream.ok_or_message("missing stream")?; + let bytes = read_stream_to_end(stream).await?; + let data = DataBlock::from_parts(header, bytes); + self.write_block(&hash, &data).await + } + /// Write a block to disk - async fn write_block(&self, hash: &Hash, data: &DataBlock) -> Result<BlockRpc, Error> { + pub(crate) async fn write_block(&self, hash: &Hash, data: &DataBlock) -> Result<(), Error> { + let tracer = opentelemetry::global::tracer("garage"); + let write_size = data.inner_buffer().len() as u64; - let res = self - .mutation_lock - .lock() + self.lock_mutate(hash) .await .write_block(hash, data, self) .bound_record_duration(&self.metrics.block_write_duration) + .with_context(Context::current_with_span( + tracer.start("BlockManagerLocked::write_block"), + )) .await?; self.metrics.bytes_written.add(write_size); - Ok(res) + Ok(()) + } + + async fn handle_get_block(&self, hash: &Hash, order_tag: Option<OrderTag>) -> Resp<BlockRpc> { + let block = match self.read_block(hash).await { + Ok(data) => data, + Err(e) => return Resp::new(Err(e)), + }; + + let (header, data) = block.into_parts(); + + let resp = Resp::new(Ok(BlockRpc::PutBlock { + hash: *hash, + header, + })) + .with_stream_from_buffer(data); + + if let Some(order_tag) = order_tag { + resp.with_order_tag(order_tag) + } else { + resp + } } /// Read block from disk, verifying it's integrity - async fn read_block(&self, hash: &Hash) -> Result<BlockRpc, Error> { + pub(crate) async fn read_block(&self, hash: &Hash) -> Result<DataBlock, Error> { let data = self .read_block_internal(hash) .bound_record_duration(&self.metrics.block_read_duration) @@ -338,7 +434,7 @@ impl BlockManager { .bytes_read .add(data.inner_buffer().len() as u64); - Ok(BlockRpc::PutBlock { hash: *hash, data }) + Ok(data) } async fn read_block_internal(&self, hash: &Hash) -> Result<DataBlock, Error> { @@ -347,7 +443,8 @@ impl BlockManager { Ok(c) => c, Err(e) => { // Not found but maybe we should have had it ?? - self.put_to_resync(hash, 2 * BLOCK_RW_TIMEOUT)?; + self.resync + .put_to_resync(hash, 2 * self.system.rpc.rpc_timeout())?; return Err(Into::into(e)); } }; @@ -361,37 +458,47 @@ impl BlockManager { drop(f); let data = if compressed { - DataBlock::Compressed(data) + DataBlock::Compressed(data.into()) } else { - DataBlock::Plain(data) + DataBlock::Plain(data.into()) }; if data.verify(*hash).is_err() { self.metrics.corruption_counter.add(1); - self.mutation_lock - .lock() + self.lock_mutate(hash) .await .move_block_to_corrupted(hash, self) .await?; - self.put_to_resync(hash, Duration::from_millis(0))?; + self.resync.put_to_resync(hash, Duration::from_millis(0))?; return Err(Error::CorruptData(*hash)); } Ok(data) } - /// Check if this node should have a block, but don't actually have it - async fn need_block(&self, hash: &Hash) -> Result<bool, Error> { - let BlockStatus { exists, needed } = self - .mutation_lock - .lock() + /// Check if this node has a block and whether it needs it + pub(crate) async fn check_block_status(&self, hash: &Hash) -> Result<BlockStatus, Error> { + self.lock_mutate(hash) .await .check_block_status(hash, self) - .await?; + .await + } + + /// Check if this node should have a block, but don't actually have it + async fn need_block(&self, hash: &Hash) -> Result<bool, Error> { + let BlockStatus { exists, needed } = self.check_block_status(hash).await?; Ok(needed.is_nonzero() && !exists) } + /// Delete block if it is not needed anymore + pub(crate) async fn delete_if_unneeded(&self, hash: &Hash) -> Result<(), Error> { + self.lock_mutate(hash) + .await + .delete_if_unneeded(hash, self) + .await + } + /// Utility: gives the path of the directory in which a block should be found fn block_dir(&self, hash: &Hash) -> PathBuf { let mut path = self.data_dir.clone(); @@ -419,431 +526,38 @@ impl BlockManager { fs::metadata(&path).await.map(|_| false).map_err(Into::into) } - // ---- Resync loop ---- - - // This part manages a queue of blocks that need to be - // "resynchronized", i.e. that need to have a check that - // they are at present if we need them, or that they are - // deleted once the garbage collection delay has passed. - // - // Here are some explanations on how the resync queue works. - // There are two Sled trees that are used to have information - // about the status of blocks that need to be resynchronized: - // - // - resync_queue: a tree that is ordered first by a timestamp - // (in milliseconds since Unix epoch) that is the time at which - // the resync must be done, and second by block hash. - // The key in this tree is just: - // concat(timestamp (8 bytes), hash (32 bytes)) - // The value is the same 32-byte hash. - // - // - resync_errors: a tree that indicates for each block - // if the last resync resulted in an error, and if so, - // the following two informations (see the ErrorCounter struct): - // - how many consecutive resync errors for this block? - // - when was the last try? - // These two informations are used to implement an - // exponential backoff retry strategy. - // The key in this tree is the 32-byte hash of the block, - // and the value is the encoded ErrorCounter value. - // - // We need to have these two trees, because the resync queue - // is not just a queue of items to process, but a set of items - // that are waiting a specific delay until we can process them - // (the delay being necessary both internally for the exponential - // backoff strategy, and exposed as a parameter when adding items - // to the queue, e.g. to wait until the GC delay has passed). - // This is why we need one tree ordered by time, and one - // ordered by identifier of item to be processed (block hash). - // - // When the worker wants to process an item it takes from - // resync_queue, it checks in resync_errors that if there is an - // exponential back-off delay to await, it has passed before we - // process the item. If not, the item in the queue is skipped - // (but added back for later processing after the time of the - // delay). - // - // An alternative that would have seemed natural is to - // only add items to resync_queue with a processing time that is - // after the delay, but there are several issues with this: - // - This requires to synchronize updates to resync_queue and - // resync_errors (with the current model, there is only one thread, - // the worker thread, that accesses resync_errors, - // so no need to synchronize) by putting them both in a lock. - // This would mean that block_incref might need to take a lock - // before doing its thing, meaning it has much more chances of - // not completing successfully if something bad happens to Garage. - // Currently Garage is not able to recover from block_incref that - // doesn't complete successfully, because it is necessary to ensure - // the consistency between the state of the block manager and - // information in the BlockRef table. - // - If a resync fails, we put that block in the resync_errors table, - // and also add it back to resync_queue to be processed after - // the exponential back-off delay, - // but maybe the block is already scheduled to be resynced again - // at another time that is before the exponential back-off delay, - // and we have no way to check that easily. This means that - // in all cases, we need to check the resync_errors table - // in the resync loop at the time when a block is popped from - // the resync_queue. - // Overall, the current design is therefore simpler and more robust - // because it tolerates inconsistencies between the resync_queue - // and resync_errors table (items being scheduled in resync_queue - // for times that are earlier than the exponential back-off delay - // is a natural condition that is handled properly). - - fn spawn_background_worker(self: Arc<Self>) { - // Launch a background workers for background resync loop processing - let background = self.system.background.clone(); - tokio::spawn(async move { - tokio::time::sleep(Duration::from_secs(10)).await; - background.spawn_worker("block resync worker".into(), move |must_exit| { - self.resync_loop(must_exit) - }); - }); - } - - fn put_to_resync(&self, hash: &Hash, delay: Duration) -> Result<(), sled::Error> { - let when = now_msec() + delay.as_millis() as u64; - self.put_to_resync_at(hash, when) - } - - fn put_to_resync_at(&self, hash: &Hash, when: u64) -> Result<(), sled::Error> { - trace!("Put resync_queue: {} {:?}", when, hash); - let mut key = u64::to_be_bytes(when).to_vec(); - key.extend(hash.as_ref()); - self.resync_queue.insert(key, hash.as_ref())?; - self.resync_notify.notify_waiters(); - Ok(()) - } - - async fn resync_loop(self: Arc<Self>, mut must_exit: watch::Receiver<bool>) { - let mut tranquilizer = Tranquilizer::new(30); - - while !*must_exit.borrow() { - match self.resync_iter(&mut must_exit).await { - Ok(true) => { - tranquilizer.tranquilize(self.background_tranquility).await; - } - Ok(false) => { - tranquilizer.reset(); - } - Err(e) => { - // The errors that we have here are only Sled errors - // We don't really know how to handle them so just ¯\_(ツ)_/¯ - // (there is kind of an assumption that Sled won't error on us, - // if it does there is not much we can do -- TODO should we just panic?) - error!( - "Could not do a resync iteration: {} (this is a very bad error)", - e - ); - tranquilizer.reset(); - } - } - } - } - - // The result of resync_iter is: - // - Ok(true) -> a block was processed (successfully or not) - // - Ok(false) -> no block was processed, but we are ready for the next iteration - // - Err(_) -> a Sled error occurred when reading/writing from resync_queue/resync_errors - async fn resync_iter( - &self, - must_exit: &mut watch::Receiver<bool>, - ) -> Result<bool, sled::Error> { - if let Some(first_pair_res) = self.resync_queue.iter().next() { - let (time_bytes, hash_bytes) = first_pair_res?; - - let time_msec = u64::from_be_bytes(time_bytes[0..8].try_into().unwrap()); - let now = now_msec(); - - if now >= time_msec { - let hash = Hash::try_from(&hash_bytes[..]).unwrap(); - - if let Some(ec) = self.resync_errors.get(hash.as_slice())? { - let ec = ErrorCounter::decode(ec); - if now < ec.next_try() { - // if next retry after an error is not yet, - // don't do resync and return early, but still - // make sure the item is still in queue at expected time - self.put_to_resync_at(&hash, ec.next_try())?; - // ec.next_try() > now >= time_msec, so this remove - // is not removing the one we added just above - // (we want to do the remove after the insert to ensure - // that the item is not lost if we crash in-between) - self.resync_queue.remove(time_bytes)?; - return Ok(false); - } - } - - let tracer = opentelemetry::global::tracer("garage"); - let trace_id = gen_uuid(); - let span = tracer - .span_builder("Resync block") - .with_trace_id( - opentelemetry::trace::TraceId::from_hex(&hex::encode( - &trace_id.as_slice()[..16], - )) - .unwrap(), - ) - .with_attributes(vec![KeyValue::new("block", format!("{:?}", hash))]) - .start(&tracer); - - let res = self - .resync_block(&hash) - .with_context(Context::current_with_span(span)) - .bound_record_duration(&self.metrics.resync_duration) - .await; - - self.metrics.resync_counter.add(1); - - if let Err(e) = &res { - self.metrics.resync_error_counter.add(1); - warn!("Error when resyncing {:?}: {}", hash, e); - - let err_counter = match self.resync_errors.get(hash.as_slice())? { - Some(ec) => ErrorCounter::decode(ec).add1(now + 1), - None => ErrorCounter::new(now + 1), - }; - - self.resync_errors - .insert(hash.as_slice(), err_counter.encode())?; - - self.put_to_resync_at(&hash, err_counter.next_try())?; - // err_counter.next_try() >= now + 1 > now, - // the entry we remove from the queue is not - // the entry we inserted with put_to_resync_at - self.resync_queue.remove(time_bytes)?; - } else { - self.resync_errors.remove(hash.as_slice())?; - self.resync_queue.remove(time_bytes)?; - } - - Ok(true) - } else { - let delay = tokio::time::sleep(Duration::from_millis(time_msec - now)); - select! { - _ = delay.fuse() => {}, - _ = self.resync_notify.notified().fuse() => {}, - _ = must_exit.changed().fuse() => {}, - } - Ok(false) - } - } else { - // Here we wait either for a notification that an item has been - // added to the queue, or for a constant delay of 10 secs to expire. - // The delay avoids a race condition where the notification happens - // between the time we checked the queue and the first poll - // to resync_notify.notified(): if that happens, we'll just loop - // back 10 seconds later, which is fine. - let delay = tokio::time::sleep(Duration::from_secs(10)); - select! { - _ = delay.fuse() => {}, - _ = self.resync_notify.notified().fuse() => {}, - _ = must_exit.changed().fuse() => {}, - } - Ok(false) - } - } - - async fn resync_block(&self, hash: &Hash) -> Result<(), Error> { - let BlockStatus { exists, needed } = self - .mutation_lock + async fn lock_mutate(&self, hash: &Hash) -> MutexGuard<'_, BlockManagerLocked> { + let tracer = opentelemetry::global::tracer("garage"); + self.mutation_lock[hash.as_slice()[0] as usize] .lock() + .with_context(Context::current_with_span( + tracer.start("Acquire mutation_lock"), + )) .await - .check_block_status(hash, self) - .await?; - - if exists != needed.is_needed() || exists != needed.is_nonzero() { - debug!( - "Resync block {:?}: exists {}, nonzero rc {}, deletable {}", - hash, - exists, - needed.is_nonzero(), - needed.is_deletable(), - ); - } - - if exists && needed.is_deletable() { - info!("Resync block {:?}: offloading and deleting", hash); - - let mut who = self.replication.write_nodes(hash); - if who.len() < self.replication.write_quorum() { - return Err(Error::Message("Not trying to offload block because we don't have a quorum of nodes to write to".to_string())); - } - who.retain(|id| *id != self.system.id); - - let msg = Arc::new(BlockRpc::NeedBlockQuery(*hash)); - let who_needs_fut = who.iter().map(|to| { - self.system.rpc.call_arc( - &self.endpoint, - *to, - msg.clone(), - RequestStrategy::with_priority(PRIO_BACKGROUND) - .with_timeout(NEED_BLOCK_QUERY_TIMEOUT), - ) - }); - let who_needs_resps = join_all(who_needs_fut).await; - - let mut need_nodes = vec![]; - for (node, needed) in who.iter().zip(who_needs_resps.into_iter()) { - match needed.err_context("NeedBlockQuery RPC")? { - BlockRpc::NeedBlockReply(needed) => { - if needed { - need_nodes.push(*node); - } - } - m => { - return Err(Error::unexpected_rpc_message(m)); - } - } - } - - if !need_nodes.is_empty() { - trace!( - "Block {:?} needed by {} nodes, sending", - hash, - need_nodes.len() - ); - - for node in need_nodes.iter() { - self.metrics - .resync_send_counter - .add(1, &[KeyValue::new("to", format!("{:?}", node))]); - } - - let put_block_message = self.read_block(hash).await?; - self.system - .rpc - .try_call_many( - &self.endpoint, - &need_nodes[..], - put_block_message, - RequestStrategy::with_priority(PRIO_BACKGROUND) - .with_quorum(need_nodes.len()) - .with_timeout(BLOCK_RW_TIMEOUT), - ) - .await - .err_context("PutBlock RPC")?; - } - info!( - "Deleting unneeded block {:?}, offload finished ({} / {})", - hash, - need_nodes.len(), - who.len() - ); - - self.mutation_lock - .lock() - .await - .delete_if_unneeded(hash, self) - .await?; - - self.rc.clear_deleted_block_rc(hash)?; - } - - if needed.is_nonzero() && !exists { - info!( - "Resync block {:?}: fetching absent but needed block (refcount > 0)", - hash - ); - - let block_data = self.rpc_get_raw_block(hash).await?; - - self.metrics.resync_recv_counter.add(1); - - self.write_block(hash, &block_data).await?; - } - - Ok(()) - } - - // ---- Utility: iteration on files in the data directory ---- - - async fn for_each_file<F, Fut, State>( - &self, - state: State, - mut f: F, - must_exit: &watch::Receiver<bool>, - ) -> Result<(), Error> - where - F: FnMut(State, Hash) -> Fut + Send, - Fut: Future<Output = Result<State, Error>> + Send, - State: Send, - { - self.for_each_file_rec(&self.data_dir, state, &mut f, must_exit) - .await - .map(|_| ()) - } - - fn for_each_file_rec<'a, F, Fut, State>( - &'a self, - path: &'a Path, - mut state: State, - f: &'a mut F, - must_exit: &'a watch::Receiver<bool>, - ) -> BoxFuture<'a, Result<State, Error>> - where - F: FnMut(State, Hash) -> Fut + Send, - Fut: Future<Output = Result<State, Error>> + Send, - State: Send + 'a, - { - async move { - let mut ls_data_dir = fs::read_dir(path).await?; - while let Some(data_dir_ent) = ls_data_dir.next_entry().await? { - if *must_exit.borrow() { - break; - } - - 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() { - state = self - .for_each_file_rec(&data_dir_ent.path(), state, f, must_exit) - .await?; - } else if name.len() == 64 { - let hash_bytes = if let Ok(h) = hex::decode(&name) { - h - } else { - continue; - }; - let mut hash = [0u8; 32]; - hash.copy_from_slice(&hash_bytes[..]); - state = f(state, hash.into()).await?; - } - } - Ok(state) - } - .boxed() } } #[async_trait] -impl EndpointHandler<BlockRpc> for BlockManager { - async fn handle( - self: &Arc<Self>, - message: &BlockRpc, - _from: NodeID, - ) -> Result<BlockRpc, Error> { - match message { - BlockRpc::PutBlock { hash, data } => self.write_block(hash, data).await, - BlockRpc::GetBlock(h) => self.read_block(h).await, - BlockRpc::NeedBlockQuery(h) => self.need_block(h).await.map(BlockRpc::NeedBlockReply), - m => Err(Error::unexpected_rpc_message(m)), +impl StreamingEndpointHandler<BlockRpc> for BlockManager { + async fn handle(self: &Arc<Self>, mut message: Req<BlockRpc>, _from: NodeID) -> Resp<BlockRpc> { + match message.msg() { + BlockRpc::PutBlock { hash, header } => Resp::new( + self.handle_put_block(*hash, *header, message.take_stream()) + .await + .map(|_| BlockRpc::Ok), + ), + BlockRpc::GetBlock(h, order_tag) => self.handle_get_block(h, *order_tag).await, + BlockRpc::NeedBlockQuery(h) => { + Resp::new(self.need_block(h).await.map(BlockRpc::NeedBlockReply)) + } + m => Resp::new(Err(Error::unexpected_rpc_message(m))), } } } -struct BlockStatus { - exists: bool, - needed: RcEntry, +pub(crate) struct BlockStatus { + pub(crate) exists: bool, + pub(crate) needed: RcEntry, } impl BlockManagerLocked { @@ -863,7 +577,7 @@ impl BlockManagerLocked { hash: &Hash, data: &DataBlock, mgr: &BlockManager, - ) -> Result<BlockRpc, Error> { + ) -> Result<(), Error> { let compressed = data.is_compressed(); let data = data.inner_buffer(); @@ -874,8 +588,8 @@ impl BlockManagerLocked { fs::create_dir_all(&directory).await?; let to_delete = match (mgr.is_block_compressed(hash).await, compressed) { - (Ok(true), _) => return Ok(BlockRpc::Ok), - (Ok(false), false) => return Ok(BlockRpc::Ok), + (Ok(true), _) => return Ok(()), + (Ok(false), false) => return Ok(()), (Ok(false), true) => { let path_to_delete = path.clone(); path.set_extension("zst"); @@ -914,7 +628,7 @@ impl BlockManagerLocked { dir.sync_all().await?; drop(dir); - Ok(BlockRpc::Ok) + Ok(()) } async fn move_block_to_corrupted(&self, hash: &Hash, mgr: &BlockManager) -> Result<(), Error> { @@ -949,49 +663,16 @@ impl BlockManagerLocked { } } -/// Counts the number of errors when resyncing a block, -/// and the time of the last try. -/// Used to implement exponential backoff. -#[derive(Clone, Copy, Debug)] -struct ErrorCounter { - errors: u64, - last_try: u64, -} - -impl ErrorCounter { - fn new(now: u64) -> Self { - Self { - errors: 1, - last_try: now, - } +async fn read_stream_to_end(mut stream: ByteStream) -> Result<Bytes, Error> { + let mut parts: Vec<Bytes> = vec![]; + while let Some(part) = stream.next().await { + parts.push(part.ok_or_message("error in stream")?); } - fn decode(data: sled::IVec) -> Self { - Self { - errors: u64::from_be_bytes(data[0..8].try_into().unwrap()), - last_try: u64::from_be_bytes(data[8..16].try_into().unwrap()), - } - } - fn encode(&self) -> Vec<u8> { - [ - u64::to_be_bytes(self.errors), - u64::to_be_bytes(self.last_try), - ] + Ok(parts + .iter() + .map(|x| &x[..]) + .collect::<Vec<_>>() .concat() - } - - fn add1(self, now: u64) -> Self { - Self { - errors: self.errors + 1, - last_try: now, - } - } - - fn delay_msec(&self) -> u64 { - (RESYNC_RETRY_DELAY.as_millis() as u64) - << std::cmp::min(self.errors - 1, RESYNC_RETRY_DELAY_MAX_BACKOFF_POWER) - } - fn next_try(&self) -> u64 { - self.last_try + self.delay_msec() - } + .into()) } diff --git a/src/block/metrics.rs b/src/block/metrics.rs index f0f541a3..477add66 100644 --- a/src/block/metrics.rs +++ b/src/block/metrics.rs @@ -1,6 +1,6 @@ use opentelemetry::{global, metrics::*}; -use garage_util::sled_counter::SledCountedTree; +use garage_db::counted_tree_hack::CountedTree; /// TableMetrics reference all counter used for metrics pub struct BlockManagerMetrics { @@ -23,7 +23,7 @@ pub struct BlockManagerMetrics { } impl BlockManagerMetrics { - pub fn new(resync_queue: SledCountedTree, resync_errors: SledCountedTree) -> Self { + pub fn new(resync_queue: CountedTree, resync_errors: CountedTree) -> Self { let meter = global::meter("garage_model/block"); Self { _resync_queue_len: meter diff --git a/src/block/rc.rs b/src/block/rc.rs index ec3ea44e..ce6defad 100644 --- a/src/block/rc.rs +++ b/src/block/rc.rs @@ -1,5 +1,7 @@ use std::convert::TryInto; +use garage_db as db; + use garage_util::data::*; use garage_util::error::*; use garage_util::time::*; @@ -7,31 +9,41 @@ use garage_util::time::*; use crate::manager::BLOCK_GC_DELAY; pub struct BlockRc { - pub(crate) rc: sled::Tree, + pub(crate) rc: db::Tree, } impl BlockRc { - pub(crate) fn new(rc: sled::Tree) -> Self { + pub(crate) fn new(rc: db::Tree) -> Self { Self { rc } } /// Increment the reference counter associated to a hash. /// Returns true if the RC goes from zero to nonzero. - pub(crate) fn block_incref(&self, hash: &Hash) -> Result<bool, Error> { - let old_rc = self - .rc - .fetch_and_update(&hash, |old| RcEntry::parse_opt(old).increment().serialize())?; - let old_rc = RcEntry::parse_opt(old_rc); + pub(crate) fn block_incref( + &self, + tx: &mut db::Transaction, + hash: &Hash, + ) -> db::TxOpResult<bool> { + let old_rc = RcEntry::parse_opt(tx.get(&self.rc, &hash)?); + match old_rc.increment().serialize() { + Some(x) => tx.insert(&self.rc, &hash, x)?, + None => unreachable!(), + }; Ok(old_rc.is_zero()) } /// Decrement the reference counter associated to a hash. /// Returns true if the RC is now zero. - pub(crate) fn block_decref(&self, hash: &Hash) -> Result<bool, Error> { - let new_rc = self - .rc - .update_and_fetch(&hash, |old| RcEntry::parse_opt(old).decrement().serialize())?; - let new_rc = RcEntry::parse_opt(new_rc); + pub(crate) fn block_decref( + &self, + tx: &mut db::Transaction, + hash: &Hash, + ) -> db::TxOpResult<bool> { + let new_rc = RcEntry::parse_opt(tx.get(&self.rc, &hash)?).decrement(); + match new_rc.serialize() { + Some(x) => tx.insert(&self.rc, &hash, x)?, + None => tx.remove(&self.rc, &hash)?, + }; Ok(matches!(new_rc, RcEntry::Deletable { .. })) } @@ -44,12 +56,15 @@ impl BlockRc { /// deletion time has passed pub(crate) fn clear_deleted_block_rc(&self, hash: &Hash) -> Result<(), Error> { let now = now_msec(); - self.rc.update_and_fetch(&hash, |rcval| { - let updated = match RcEntry::parse_opt(rcval) { - RcEntry::Deletable { at_time } if now > at_time => RcEntry::Absent, - v => v, + self.rc.db().transaction(|mut 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, &hash)?; + } + _ => (), }; - updated.serialize() + tx.commit(()) })?; Ok(()) } diff --git a/src/block/repair.rs b/src/block/repair.rs new file mode 100644 index 00000000..e2884b69 --- /dev/null +++ b/src/block/repair.rs @@ -0,0 +1,466 @@ +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())); + } + } + } + } +} diff --git a/src/block/resync.rs b/src/block/resync.rs new file mode 100644 index 00000000..ada3ac54 --- /dev/null +++ b/src/block/resync.rs @@ -0,0 +1,589 @@ +use std::collections::HashSet; +use std::convert::TryInto; +use std::sync::{Arc, Mutex}; +use std::time::Duration; + +use arc_swap::ArcSwap; +use async_trait::async_trait; +use serde::{Deserialize, Serialize}; + +use tokio::select; +use tokio::sync::{watch, Notify}; + +use opentelemetry::{ + trace::{FutureExt as OtelFutureExt, TraceContextExt, Tracer}, + Context, KeyValue, +}; + +use garage_db as db; +use garage_db::counted_tree_hack::CountedTree; + +use garage_util::background::*; +use garage_util::data::*; +use garage_util::error::*; +use garage_util::metrics::RecordDuration; +use garage_util::persister::Persister; +use garage_util::time::*; +use garage_util::tranquilizer::Tranquilizer; + +use garage_rpc::system::System; +use garage_rpc::*; + +use garage_table::replication::TableReplication; + +use crate::manager::*; + +// The delay between the time where a resync operation fails +// and the time when it is retried, with exponential backoff +// (multiplied by 2, 4, 8, 16, etc. for every consecutive failure). +pub(crate) const RESYNC_RETRY_DELAY: Duration = Duration::from_secs(60); +// The minimum retry delay is 60 seconds = 1 minute +// The maximum retry delay is 60 seconds * 2^6 = 60 seconds << 6 = 64 minutes (~1 hour) +pub(crate) const RESYNC_RETRY_DELAY_MAX_BACKOFF_POWER: u64 = 6; + +// No more than 4 resync workers can be running in the system +pub(crate) const MAX_RESYNC_WORKERS: usize = 4; +// Resync tranquility is initially set to 2, but can be changed in the CLI +// and the updated version is persisted over Garage restarts +const INITIAL_RESYNC_TRANQUILITY: u32 = 2; + +pub struct BlockResyncManager { + pub(crate) queue: CountedTree, + pub(crate) notify: Notify, + pub(crate) errors: CountedTree, + + busy_set: BusySet, + + persister: Persister<ResyncPersistedConfig>, + persisted: ArcSwap<ResyncPersistedConfig>, +} + +#[derive(Serialize, Deserialize, Clone, Copy)] +struct ResyncPersistedConfig { + n_workers: usize, + tranquility: u32, +} + +enum ResyncIterResult { + BusyDidSomething, + BusyDidNothing, + IdleFor(Duration), +} + +type BusySet = Arc<Mutex<HashSet<Vec<u8>>>>; + +struct BusyBlock { + time_bytes: Vec<u8>, + hash_bytes: Vec<u8>, + busy_set: BusySet, +} + +impl BlockResyncManager { + pub(crate) fn new(db: &db::Db, system: &System) -> Self { + let queue = db + .open_tree("block_local_resync_queue") + .expect("Unable to open block_local_resync_queue tree"); + let queue = CountedTree::new(queue).expect("Could not count block_local_resync_queue"); + + let errors = db + .open_tree("block_local_resync_errors") + .expect("Unable to open block_local_resync_errors tree"); + let errors = CountedTree::new(errors).expect("Could not count block_local_resync_errors"); + + let persister = Persister::new(&system.metadata_dir, "resync_cfg"); + let persisted = match persister.load() { + Ok(v) => v, + Err(_) => ResyncPersistedConfig { + n_workers: 1, + tranquility: INITIAL_RESYNC_TRANQUILITY, + }, + }; + + Self { + queue, + notify: Notify::new(), + errors, + busy_set: Arc::new(Mutex::new(HashSet::new())), + persister, + persisted: ArcSwap::new(Arc::new(persisted)), + } + } + + /// Get lenght of resync queue + pub fn queue_len(&self) -> Result<usize, Error> { + // This currently can't return an error because the CountedTree hack + // doesn't error on .len(), but this will change when we remove the hack + // (hopefully someday!) + Ok(self.queue.len()) + } + + /// Get number of blocks that have an error + pub fn errors_len(&self) -> Result<usize, Error> { + // (see queue_len comment) + Ok(self.errors.len()) + } + + // ---- Resync loop ---- + + // This part manages a queue of blocks that need to be + // "resynchronized", i.e. that need to have a check that + // they are at present if we need them, or that they are + // deleted once the garbage collection delay has passed. + // + // Here are some explanations on how the resync queue works. + // There are two Sled trees that are used to have information + // about the status of blocks that need to be resynchronized: + // + // - resync.queue: a tree that is ordered first by a timestamp + // (in milliseconds since Unix epoch) that is the time at which + // the resync must be done, and second by block hash. + // The key in this tree is just: + // concat(timestamp (8 bytes), hash (32 bytes)) + // The value is the same 32-byte hash. + // + // - resync.errors: a tree that indicates for each block + // if the last resync resulted in an error, and if so, + // the following two informations (see the ErrorCounter struct): + // - how many consecutive resync errors for this block? + // - when was the last try? + // These two informations are used to implement an + // exponential backoff retry strategy. + // The key in this tree is the 32-byte hash of the block, + // and the value is the encoded ErrorCounter value. + // + // We need to have these two trees, because the resync queue + // is not just a queue of items to process, but a set of items + // that are waiting a specific delay until we can process them + // (the delay being necessary both internally for the exponential + // backoff strategy, and exposed as a parameter when adding items + // to the queue, e.g. to wait until the GC delay has passed). + // This is why we need one tree ordered by time, and one + // ordered by identifier of item to be processed (block hash). + // + // When the worker wants to process an item it takes from + // resync.queue, it checks in resync.errors that if there is an + // exponential back-off delay to await, it has passed before we + // process the item. If not, the item in the queue is skipped + // (but added back for later processing after the time of the + // delay). + // + // An alternative that would have seemed natural is to + // only add items to resync.queue with a processing time that is + // after the delay, but there are several issues with this: + // - This requires to synchronize updates to resync.queue and + // resync.errors (with the current model, there is only one thread, + // the worker thread, that accesses resync.errors, + // so no need to synchronize) by putting them both in a lock. + // This would mean that block_incref might need to take a lock + // before doing its thing, meaning it has much more chances of + // not completing successfully if something bad happens to Garage. + // Currently Garage is not able to recover from block_incref that + // doesn't complete successfully, because it is necessary to ensure + // the consistency between the state of the block manager and + // information in the BlockRef table. + // - If a resync fails, we put that block in the resync.errors table, + // and also add it back to resync.queue to be processed after + // the exponential back-off delay, + // but maybe the block is already scheduled to be resynced again + // at another time that is before the exponential back-off delay, + // and we have no way to check that easily. This means that + // in all cases, we need to check the resync.errors table + // in the resync loop at the time when a block is popped from + // the resync.queue. + // Overall, the current design is therefore simpler and more robust + // because it tolerates inconsistencies between the resync.queue + // and resync.errors table (items being scheduled in resync.queue + // for times that are earlier than the exponential back-off delay + // is a natural condition that is handled properly). + + pub(crate) fn put_to_resync(&self, hash: &Hash, delay: Duration) -> db::Result<()> { + let when = now_msec() + delay.as_millis() as u64; + self.put_to_resync_at(hash, when) + } + + pub(crate) fn put_to_resync_at(&self, hash: &Hash, when: u64) -> db::Result<()> { + trace!("Put resync_queue: {} {:?}", when, hash); + let mut key = u64::to_be_bytes(when).to_vec(); + key.extend(hash.as_ref()); + self.queue.insert(key, hash.as_ref())?; + self.notify.notify_waiters(); + Ok(()) + } + + async fn resync_iter(&self, manager: &BlockManager) -> Result<ResyncIterResult, db::Error> { + if let Some(block) = self.get_block_to_resync()? { + let time_msec = u64::from_be_bytes(block.time_bytes[0..8].try_into().unwrap()); + let now = now_msec(); + + if now >= time_msec { + let hash = Hash::try_from(&block.hash_bytes[..]).unwrap(); + + if let Some(ec) = self.errors.get(hash.as_slice())? { + let ec = ErrorCounter::decode(&ec); + if now < ec.next_try() { + // if next retry after an error is not yet, + // don't do resync and return early, but still + // make sure the item is still in queue at expected time + self.put_to_resync_at(&hash, ec.next_try())?; + // ec.next_try() > now >= time_msec, so this remove + // is not removing the one we added just above + // (we want to do the remove after the insert to ensure + // that the item is not lost if we crash in-between) + self.queue.remove(&block.time_bytes)?; + return Ok(ResyncIterResult::BusyDidNothing); + } + } + + let tracer = opentelemetry::global::tracer("garage"); + let trace_id = gen_uuid(); + let span = tracer + .span_builder("Resync block") + .with_trace_id( + opentelemetry::trace::TraceId::from_hex(&hex::encode( + &trace_id.as_slice()[..16], + )) + .unwrap(), + ) + .with_attributes(vec![KeyValue::new("block", format!("{:?}", hash))]) + .start(&tracer); + + let res = self + .resync_block(manager, &hash) + .with_context(Context::current_with_span(span)) + .bound_record_duration(&manager.metrics.resync_duration) + .await; + + manager.metrics.resync_counter.add(1); + + if let Err(e) = &res { + manager.metrics.resync_error_counter.add(1); + warn!("Error when resyncing {:?}: {}", hash, e); + + let err_counter = match self.errors.get(hash.as_slice())? { + Some(ec) => ErrorCounter::decode(&ec).add1(now + 1), + None => ErrorCounter::new(now + 1), + }; + + self.errors.insert(hash.as_slice(), err_counter.encode())?; + + self.put_to_resync_at(&hash, err_counter.next_try())?; + // err_counter.next_try() >= now + 1 > now, + // the entry we remove from the queue is not + // the entry we inserted with put_to_resync_at + self.queue.remove(&block.time_bytes)?; + } else { + self.errors.remove(hash.as_slice())?; + self.queue.remove(&block.time_bytes)?; + } + + Ok(ResyncIterResult::BusyDidSomething) + } else { + Ok(ResyncIterResult::IdleFor(Duration::from_millis( + time_msec - now, + ))) + } + } else { + // Here we wait either for a notification that an item has been + // added to the queue, or for a constant delay of 10 secs to expire. + // The delay avoids a race condition where the notification happens + // between the time we checked the queue and the first poll + // to resync_notify.notified(): if that happens, we'll just loop + // back 10 seconds later, which is fine. + Ok(ResyncIterResult::IdleFor(Duration::from_secs(10))) + } + } + + fn get_block_to_resync(&self) -> Result<Option<BusyBlock>, db::Error> { + let mut busy = self.busy_set.lock().unwrap(); + for it in self.queue.iter()? { + let (time_bytes, hash_bytes) = it?; + if !busy.contains(&time_bytes) { + busy.insert(time_bytes.clone()); + return Ok(Some(BusyBlock { + time_bytes, + hash_bytes, + busy_set: self.busy_set.clone(), + })); + } + } + Ok(None) + } + + async fn resync_block(&self, manager: &BlockManager, hash: &Hash) -> Result<(), Error> { + let BlockStatus { exists, needed } = manager.check_block_status(hash).await?; + + if exists != needed.is_needed() || exists != needed.is_nonzero() { + debug!( + "Resync block {:?}: exists {}, nonzero rc {}, deletable {}", + hash, + exists, + needed.is_nonzero(), + needed.is_deletable(), + ); + } + + if exists && needed.is_deletable() { + info!("Resync block {:?}: offloading and deleting", hash); + + let mut who = manager.replication.write_nodes(hash); + if who.len() < manager.replication.write_quorum() { + return Err(Error::Message("Not trying to offload block because we don't have a quorum of nodes to write to".to_string())); + } + who.retain(|id| *id != manager.system.id); + + let who_needs_resps = manager + .system + .rpc + .call_many( + &manager.endpoint, + &who, + BlockRpc::NeedBlockQuery(*hash), + RequestStrategy::with_priority(PRIO_BACKGROUND), + ) + .await?; + + let mut need_nodes = vec![]; + for (node, needed) in who_needs_resps { + match needed.err_context("NeedBlockQuery RPC")? { + BlockRpc::NeedBlockReply(needed) => { + if needed { + need_nodes.push(node); + } + } + m => { + return Err(Error::unexpected_rpc_message(m)); + } + } + } + + if !need_nodes.is_empty() { + trace!( + "Block {:?} needed by {} nodes, sending", + hash, + need_nodes.len() + ); + + for node in need_nodes.iter() { + manager + .metrics + .resync_send_counter + .add(1, &[KeyValue::new("to", format!("{:?}", node))]); + } + + let block = manager.read_block(hash).await?; + let (header, bytes) = block.into_parts(); + let put_block_message = Req::new(BlockRpc::PutBlock { + hash: *hash, + header, + })? + .with_stream_from_buffer(bytes); + manager + .system + .rpc + .try_call_many( + &manager.endpoint, + &need_nodes[..], + put_block_message, + RequestStrategy::with_priority(PRIO_BACKGROUND) + .with_quorum(need_nodes.len()), + ) + .await + .err_context("PutBlock RPC")?; + } + info!( + "Deleting unneeded block {:?}, offload finished ({} / {})", + hash, + need_nodes.len(), + who.len() + ); + + manager.delete_if_unneeded(hash).await?; + + manager.rc.clear_deleted_block_rc(hash)?; + } + + if needed.is_nonzero() && !exists { + info!( + "Resync block {:?}: fetching absent but needed block (refcount > 0)", + hash + ); + + let block_data = manager.rpc_get_raw_block(hash, None).await?; + + manager.metrics.resync_recv_counter.add(1); + + manager.write_block(hash, &block_data).await?; + } + + Ok(()) + } + + async fn update_persisted( + &self, + update: impl Fn(&mut ResyncPersistedConfig), + ) -> Result<(), Error> { + let mut cfg: ResyncPersistedConfig = *self.persisted.load().as_ref(); + update(&mut cfg); + self.persister.save_async(&cfg).await?; + self.persisted.store(Arc::new(cfg)); + self.notify.notify_waiters(); + Ok(()) + } + + pub async fn set_n_workers(&self, n_workers: usize) -> Result<(), Error> { + if !(1..=MAX_RESYNC_WORKERS).contains(&n_workers) { + return Err(Error::Message(format!( + "Invalid number of resync workers, must be between 1 and {}", + MAX_RESYNC_WORKERS + ))); + } + self.update_persisted(|cfg| cfg.n_workers = n_workers).await + } + + pub async fn set_tranquility(&self, tranquility: u32) -> Result<(), Error> { + self.update_persisted(|cfg| cfg.tranquility = tranquility) + .await + } +} + +impl Drop for BusyBlock { + fn drop(&mut self) { + let mut busy = self.busy_set.lock().unwrap(); + busy.remove(&self.time_bytes); + } +} + +pub(crate) struct ResyncWorker { + index: usize, + manager: Arc<BlockManager>, + tranquilizer: Tranquilizer, + next_delay: Duration, +} + +impl ResyncWorker { + pub(crate) fn new(index: usize, manager: Arc<BlockManager>) -> Self { + Self { + index, + manager, + tranquilizer: Tranquilizer::new(30), + next_delay: Duration::from_secs(10), + } + } +} + +#[async_trait] +impl Worker for ResyncWorker { + fn name(&self) -> String { + format!("Block resync worker #{}", self.index + 1) + } + + fn info(&self) -> Option<String> { + let persisted = self.manager.resync.persisted.load(); + + if self.index >= persisted.n_workers { + return Some("(unused)".into()); + } + + let mut ret = vec![]; + ret.push(format!("tranquility = {}", persisted.tranquility)); + + let qlen = self.manager.resync.queue_len().unwrap_or(0); + if qlen > 0 { + ret.push(format!("{} blocks in queue", qlen)); + } + + let elen = self.manager.resync.errors_len().unwrap_or(0); + if elen > 0 { + ret.push(format!("{} blocks in error state", elen)); + } + + Some(ret.join(", ")) + } + + async fn work(&mut self, _must_exit: &mut watch::Receiver<bool>) -> Result<WorkerState, Error> { + if self.index >= self.manager.resync.persisted.load().n_workers { + return Ok(WorkerState::Idle); + } + + self.tranquilizer.reset(); + match self.manager.resync.resync_iter(&self.manager).await { + Ok(ResyncIterResult::BusyDidSomething) => Ok(self + .tranquilizer + .tranquilize_worker(self.manager.resync.persisted.load().tranquility)), + Ok(ResyncIterResult::BusyDidNothing) => Ok(WorkerState::Busy), + Ok(ResyncIterResult::IdleFor(delay)) => { + self.next_delay = delay; + Ok(WorkerState::Idle) + } + Err(e) => { + // The errors that we have here are only Sled errors + // We don't really know how to handle them so just ¯\_(ツ)_/¯ + // (there is kind of an assumption that Sled won't error on us, + // if it does there is not much we can do -- TODO should we just panic?) + // Here we just give the error to the worker manager, + // it will print it to the logs and increment a counter + Err(e.into()) + } + } + } + + async fn wait_for_work(&mut self, _must_exit: &watch::Receiver<bool>) -> WorkerState { + while self.index >= self.manager.resync.persisted.load().n_workers { + self.manager.resync.notify.notified().await + } + + select! { + _ = tokio::time::sleep(self.next_delay) => (), + _ = self.manager.resync.notify.notified() => (), + }; + + WorkerState::Busy + } +} + +/// Counts the number of errors when resyncing a block, +/// and the time of the last try. +/// Used to implement exponential backoff. +#[derive(Clone, Copy, Debug)] +struct ErrorCounter { + errors: u64, + last_try: u64, +} + +impl ErrorCounter { + fn new(now: u64) -> Self { + Self { + errors: 1, + last_try: now, + } + } + + fn decode(data: &[u8]) -> Self { + Self { + errors: u64::from_be_bytes(data[0..8].try_into().unwrap()), + last_try: u64::from_be_bytes(data[8..16].try_into().unwrap()), + } + } + fn encode(&self) -> Vec<u8> { + [ + u64::to_be_bytes(self.errors), + u64::to_be_bytes(self.last_try), + ] + .concat() + } + + fn add1(self, now: u64) -> Self { + Self { + errors: self.errors + 1, + last_try: now, + } + } + + fn delay_msec(&self) -> u64 { + (RESYNC_RETRY_DELAY.as_millis() as u64) + << std::cmp::min(self.errors - 1, RESYNC_RETRY_DELAY_MAX_BACKOFF_POWER) + } + fn next_try(&self) -> u64 { + self.last_try + self.delay_msec() + } +} |