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::io::{AsyncReadExt, AsyncWriteExt}; use tokio::sync::{mpsc, Mutex}; use garage_db as db; use garage_util::data::*; use garage_util::error::*; use garage_util::metrics::RecordDuration; use garage_rpc::system::System; use garage_rpc::*; 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 pub(crate) const BLOCK_RW_TIMEOUT: Duration = Duration::from_secs(30); // The delay between the moment when the reference counter // drops to zero, and the moment where we allow ourselves // to delete the block locally. pub(crate) const BLOCK_GC_DELAY: Duration = Duration::from_secs(600); /// RPC messages used to share blocks of data between nodes #[derive(Debug, Serialize, Deserialize)] pub enum BlockRpc { Ok, /// Message to ask for a block of data, by hash GetBlock(Hash), /// Message to send a block of data, either because requested, of for first delivery of new /// block PutBlock { hash: Hash, data: DataBlock, }, /// Ask other node if they should have this block, but don't actually have it NeedBlockQuery(Hash), /// Response : whether the node do require that block NeedBlockReply(bool), } impl Rpc for BlockRpc { type Response = Result<BlockRpc, Error>; } /// The block manager, handling block exchange between nodes, and block storage on local node pub struct BlockManager { /// Replication strategy, allowing to find on which node blocks should be located pub replication: TableShardedReplication, /// Directory in which block are stored pub data_dir: PathBuf, compression_level: Option<i32>, mutation_lock: Mutex<BlockManagerLocked>, pub(crate) rc: BlockRc, pub resync: BlockResyncManager, pub(crate) system: Arc<System>, pub(crate) endpoint: Arc<Endpoint<BlockRpc, Self>>, pub(crate) metrics: BlockManagerMetrics, tx_scrub_command: mpsc::Sender<ScrubWorkerCommand>, } // This custom struct contains functions that must only be ran // when the lock is held. We ensure that it is the case by storing // it INSIDE a Mutex. struct BlockManagerLocked(); impl BlockManager { pub fn new( db: &db::Db, data_dir: PathBuf, compression_level: Option<i32>, replication: TableShardedReplication, system: Arc<System>, ) -> Arc<Self> { let rc = db .open_tree("block_local_rc") .expect("Unable to open block_local_rc tree"); let rc = BlockRc::new(rc); let resync = BlockResyncManager::new(db, &system); let endpoint = system .netapp .endpoint("garage_block/manager.rs/Rpc".to_string()); let manager_locked = BlockManagerLocked(); 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, mutation_lock: Mutex::new(manager_locked), rc, resync, system, endpoint, metrics, tx_scrub_command: scrub_tx, }); block_manager.endpoint.set_handler(block_manager.clone()); // 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 pub(crate) async fn rpc_get_raw_block(&self, hash: &Hash) -> Result<DataBlock, 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?; for resp in resps { if let BlockRpc::PutBlock { data, .. } = resp { return Ok(data); } } Err(Error::Message(format!( "Unable to read block {:?}: no valid blocks returned", hash ))) } // ---- Public interface ---- /// 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) } /// Send block to nodes that should have it pub async fn rpc_put_block(&self, hash: Hash, data: Vec<u8>) -> Result<(), Error> { let who = self.replication.write_nodes(&hash); let data = DataBlock::from_buffer(data, self.compression_level); 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), ) .await?; Ok(()) } /// Get number of items in the refcount table pub fn rc_len(&self) -> Result<usize, Error> { Ok(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: &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. let this = self.clone(); tokio::spawn(async move { if let Err(e) = this.resync.put_to_resync(&hash, 2 * BLOCK_RW_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: &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. 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 ---- /// Write a block to disk pub(crate) async fn write_block( &self, hash: &Hash, data: &DataBlock, ) -> Result<BlockRpc, Error> { let write_size = data.inner_buffer().len() as u64; let res = self .mutation_lock .lock() .await .write_block(hash, data, self) .bound_record_duration(&self.metrics.block_write_duration) .await?; self.metrics.bytes_written.add(write_size); Ok(res) } /// Read block from disk, verifying it's integrity pub(crate) async fn read_block(&self, hash: &Hash) -> Result<BlockRpc, Error> { let data = self .read_block_internal(hash) .bound_record_duration(&self.metrics.block_read_duration) .await?; self.metrics .bytes_read .add(data.inner_buffer().len() as u64); Ok(BlockRpc::PutBlock { hash: *hash, data }) } async fn read_block_internal(&self, hash: &Hash) -> Result<DataBlock, Error> { let mut path = self.block_path(hash); let compressed = match self.is_block_compressed(hash).await { Ok(c) => c, Err(e) => { // Not found but maybe we should have had it ?? self.resync.put_to_resync(hash, 2 * BLOCK_RW_TIMEOUT)?; return Err(Into::into(e)); } }; if compressed { path.set_extension("zst"); } let mut f = fs::File::open(&path).await?; let mut data = vec![]; f.read_to_end(&mut data).await?; drop(f); let data = if compressed { DataBlock::Compressed(data) } else { DataBlock::Plain(data) }; if data.verify(*hash).is_err() { self.metrics.corruption_counter.add(1); self.mutation_lock .lock() .await .move_block_to_corrupted(hash, self) .await?; self.resync.put_to_resync(hash, Duration::from_millis(0))?; return Err(Error::CorruptData(*hash)); } Ok(data) } /// 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.mutation_lock .lock() .await .check_block_status(hash, self) .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.mutation_lock .lock() .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(); path.push(hex::encode(&hash.as_slice()[0..1])); path.push(hex::encode(&hash.as_slice()[1..2])); path } /// Utility: give the full path where a block should be found, minus extension if block is /// compressed fn block_path(&self, hash: &Hash) -> PathBuf { let mut path = self.block_dir(hash); path.push(hex::encode(hash.as_ref())); path } /// Utility: check if block is stored compressed. Error if block is not stored async fn is_block_compressed(&self, hash: &Hash) -> Result<bool, Error> { let mut path = self.block_path(hash); path.set_extension("zst"); if fs::metadata(&path).await.is_ok() { return Ok(true); } path.set_extension(""); fs::metadata(&path).await.map(|_| false).map_err(Into::into) } } #[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)), } } } pub(crate) struct BlockStatus { pub(crate) exists: bool, pub(crate) needed: RcEntry, } impl BlockManagerLocked { async fn check_block_status( &self, hash: &Hash, mgr: &BlockManager, ) -> Result<BlockStatus, Error> { let exists = mgr.is_block_compressed(hash).await.is_ok(); let needed = mgr.rc.get_block_rc(hash)?; Ok(BlockStatus { exists, needed }) } async fn write_block( &self, hash: &Hash, data: &DataBlock, mgr: &BlockManager, ) -> Result<BlockRpc, Error> { let compressed = data.is_compressed(); let data = data.inner_buffer(); let mut path = mgr.block_dir(hash); let directory = path.clone(); path.push(hex::encode(hash)); 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(false), true) => { let path_to_delete = path.clone(); path.set_extension("zst"); Some(path_to_delete) } (Err(_), compressed) => { if compressed { path.set_extension("zst"); } None } }; let mut path2 = path.clone(); path2.set_extension("tmp"); let mut f = fs::File::create(&path2).await?; f.write_all(data).await?; f.sync_all().await?; drop(f); fs::rename(path2, path).await?; if let Some(to_delete) = to_delete { fs::remove_file(to_delete).await?; } // We want to ensure that when this function returns, data is properly persisted // to disk. The first step is the sync_all above that does an fsync on the data file. // Now, we do an fsync on the containing directory, to ensure that the rename // is persisted properly. See: // http://thedjbway.b0llix.net/qmail/syncdir.html let dir = fs::OpenOptions::new() .read(true) .mode(0) .open(directory) .await?; dir.sync_all().await?; drop(dir); Ok(BlockRpc::Ok) } async fn move_block_to_corrupted(&self, hash: &Hash, mgr: &BlockManager) -> Result<(), Error> { warn!( "Block {:?} is corrupted. Renaming to .corrupted and resyncing.", hash ); let mut path = mgr.block_path(hash); let mut path2 = path.clone(); if mgr.is_block_compressed(hash).await? { path.set_extension("zst"); path2.set_extension("zst.corrupted"); } else { path2.set_extension("corrupted"); } fs::rename(path, path2).await?; Ok(()) } async fn delete_if_unneeded(&self, hash: &Hash, mgr: &BlockManager) -> Result<(), Error> { let BlockStatus { exists, needed } = self.check_block_status(hash, mgr).await?; if exists && needed.is_deletable() { let mut path = mgr.block_path(hash); if mgr.is_block_compressed(hash).await? { path.set_extension("zst"); } fs::remove_file(path).await?; mgr.metrics.delete_counter.add(1); } Ok(()) } }