use std::path::{Path, PathBuf}; use std::sync::Arc; use std::time::Duration; use arc_swap::ArcSwapOption; use async_trait::async_trait; use futures::future::*; use futures::select; use serde::{Deserialize, Serialize}; use tokio::fs; use tokio::io::{AsyncReadExt, AsyncWriteExt}; use tokio::sync::{watch, Mutex, Notify}; use tokio::time::Instant; use garage_util::data::*; use garage_util::error::Error; use garage_util::time::*; use garage_rpc::system::System; use garage_rpc::*; use garage_table::replication::{TableReplication, TableShardedReplication}; use crate::block_ref_table::*; use crate::garage::Garage; /// Size under which data will be stored inlined in database instead of as files pub const INLINE_THRESHOLD: usize = 3072; pub const BACKGROUND_WORKERS: u64 = 2; const BLOCK_RW_TIMEOUT: Duration = Duration::from_secs(42); const BLOCK_GC_TIMEOUT: Duration = Duration::from_secs(60); const NEED_BLOCK_QUERY_TIMEOUT: Duration = Duration::from_secs(5); const RESYNC_RETRY_TIMEOUT: Duration = Duration::from_secs(10); /// 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(PutBlockMessage), /// 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), } /// Structure used to send a block #[derive(Debug, Serialize, Deserialize)] pub struct PutBlockMessage { /// Hash of the block pub hash: Hash, /// Content of the block #[serde(with = "serde_bytes")] pub data: Vec, } impl Rpc for BlockRpc { type Response = Result; } /// 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, mutation_lock: Mutex, rc: sled::Tree, resync_queue: sled::Tree, resync_notify: Notify, system: Arc, endpoint: Arc>, pub(crate) garage: ArcSwapOption, } // 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: &sled::Db, data_dir: PathBuf, replication: TableShardedReplication, system: Arc, ) -> Arc { let rc = db .open_tree("block_local_rc") .expect("Unable to open block_local_rc tree"); let resync_queue = db .open_tree("block_local_resync_queue") .expect("Unable to open block_local_resync_queue tree"); let endpoint = system .netapp .endpoint("garage_model/block.rs/Rpc".to_string()); let manager_locked = BlockManagerLocked(); let block_manager = Arc::new(Self { replication, data_dir, mutation_lock: Mutex::new(manager_locked), rc, resync_queue, resync_notify: Notify::new(), system, endpoint, garage: ArcSwapOption::from(None), }); block_manager.endpoint.set_handler(block_manager.clone()); block_manager } // ---- Public interface ---- /// Ask nodes that might have a block for it pub async fn rpc_get_block(&self, hash: &Hash) -> Result, 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(msg) = resp { return Ok(msg.data); } } Err(Error::Message(format!( "Unable to read block {:?}: no valid blocks returned", hash ))) } /// Send block to nodes that should have it pub async fn rpc_put_block(&self, hash: Hash, data: Vec) -> Result<(), Error> { let who = self.replication.write_nodes(&hash); self.system .rpc .try_call_many( &self.endpoint, &who[..], BlockRpc::PutBlock(PutBlockMessage { hash, data }), RequestStrategy::with_priority(PRIO_NORMAL) .with_quorum(self.replication.write_quorum()) .with_timeout(BLOCK_RW_TIMEOUT), ) .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) -> Result<(), Error> { // 1. Repair blocks from RC table let garage = self.garage.load_full().unwrap(); let mut last_hash = None; for (i, entry) in garage.block_ref_table.data.store.iter().enumerate() { let (_k, v_bytes) = entry?; let block_ref = rmp_serde::decode::from_read_ref::<_, BlockRef>(v_bytes.as_ref())?; if Some(&block_ref.block) == last_hash.as_ref() { continue; } if !block_ref.deleted.get() { last_hash = Some(block_ref.block); self.put_to_resync(&block_ref.block, 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)) }, must_exit, ) .await } /// Get lenght of resync queue pub fn resync_queue_len(&self) -> usize { self.resync_queue.len() } /// Get number of items in the refcount table pub fn rc_len(&self) -> usize { self.rc.len() } //// ----- 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> { let old_rc = self.rc.fetch_and_update(&hash, |old| { let old_v = old.map(u64_from_be_bytes).unwrap_or(0); Some(u64::to_be_bytes(old_v + 1).to_vec()) })?; let old_rc = old_rc.map(u64_from_be_bytes).unwrap_or(0); if old_rc == 0 { self.put_to_resync(hash, BLOCK_RW_TIMEOUT)?; } Ok(()) } /// Decrement the number of time a block is used pub fn block_decref(&self, hash: &Hash) -> Result<(), Error> { let new_rc = self.rc.update_and_fetch(&hash, |old| { let old_v = old.map(u64_from_be_bytes).unwrap_or(0); if old_v > 1 { Some(u64::to_be_bytes(old_v - 1).to_vec()) } else { None } })?; if new_rc.is_none() { self.put_to_resync(hash, BLOCK_GC_TIMEOUT)?; } Ok(()) } /// Read a block's reference count pub fn get_block_rc(&self, hash: &Hash) -> Result { Ok(self .rc .get(hash.as_ref())? .map(u64_from_be_bytes) .unwrap_or(0)) } // ---- Reading and writing blocks locally ---- /// Write a block to disk async fn write_block(&self, hash: &Hash, data: &[u8]) -> Result { self.mutation_lock .lock() .await .write_block(hash, data, self) .await } /// Read block from disk, verifying it's integrity async fn read_block(&self, hash: &Hash) -> Result { let path = self.block_path(hash); let mut f = match fs::File::open(&path).await { Ok(f) => f, Err(e) => { // Not found but maybe we should have had it ?? self.put_to_resync(hash, Duration::from_millis(0))?; return Err(Into::into(e)); } }; let mut data = vec![]; f.read_to_end(&mut data).await?; drop(f); if blake2sum(&data[..]) != *hash { self.mutation_lock .lock() .await .move_block_to_corrupted(hash, self) .await?; return Err(Error::CorruptData(*hash)); } Ok(BlockRpc::PutBlock(PutBlockMessage { hash: *hash, data })) } /// Check if this node should have a block, but don't actually have it async fn need_block(&self, hash: &Hash) -> Result { let BlockStatus { exists, needed } = self .mutation_lock .lock() .await .check_block_status(hash, self) .await?; Ok(needed && !exists) } /// 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 fn block_path(&self, hash: &Hash) -> PathBuf { let mut path = self.block_dir(hash); path.push(hex::encode(hash.as_ref())); path } // ---- Resync loop ---- pub fn spawn_background_worker(self: Arc) { // Launch 2 simultaneous workers for background resync loop preprocessing for i in 0..BACKGROUND_WORKERS { let bm2 = self.clone(); let background = self.system.background.clone(); tokio::spawn(async move { tokio::time::sleep(Duration::from_secs(10 * (i + 1))).await; background.spawn_worker(format!("block resync worker {}", i), move |must_exit| { bm2.resync_loop(must_exit) }); }); } } fn put_to_resync(&self, hash: &Hash, delay: Duration) -> Result<(), Error> { let when = now_msec() + delay.as_millis() as u64; 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, mut must_exit: watch::Receiver) { while !*must_exit.borrow() { if let Err(e) = self.resync_iter(&mut must_exit).await { warn!("Error in block resync loop: {}", e); select! { _ = tokio::time::sleep(Duration::from_secs(1)).fuse() => {}, _ = must_exit.changed().fuse() => {}, } } } } async fn resync_iter(&self, must_exit: &mut watch::Receiver) -> Result<(), Error> { if let Some(first_item) = self.resync_queue.iter().next() { let (time_bytes, hash_bytes) = first_item?; let time_msec = u64_from_be_bytes(&time_bytes[0..8]); let now = now_msec(); if now >= time_msec { let hash = Hash::try_from(&hash_bytes[..]).unwrap(); let res = self.resync_block(&hash).await; if let Err(e) = &res { warn!("Error when resyncing {:?}: {}", hash, e); self.put_to_resync(&hash, RESYNC_RETRY_TIMEOUT)?; } self.resync_queue.remove(&time_bytes)?; res?; // propagate error to delay main loop } else { let delay = tokio::time::sleep(Duration::from_millis(time_msec - now)); select! { _ = delay.fuse() => {}, _ = self.resync_notify.notified().fuse() => {}, _ = must_exit.changed().fuse() => {}, } } } else { select! { _ = self.resync_notify.notified().fuse() => {}, _ = must_exit.changed().fuse() => {}, } } Ok(()) } async fn resync_block(&self, hash: &Hash) -> Result<(), Error> { let BlockStatus { exists, needed } = self .mutation_lock .lock() .await .check_block_status(hash, self) .await?; if exists != needed { info!( "Resync block {:?}: exists {}, needed {}", hash, exists, needed ); } if exists && !needed { trace!("Offloading block {:?}", 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_NORMAL) .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? { BlockRpc::NeedBlockReply(needed) => { if needed { need_nodes.push(*node); } } _ => { return Err(Error::Message( "Unexpected response to NeedBlockQuery RPC".to_string(), )); } } } if !need_nodes.is_empty() { trace!( "Block {:?} needed by {} nodes, sending", hash, need_nodes.len() ); 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_NORMAL) .with_quorum(need_nodes.len()) .with_timeout(BLOCK_RW_TIMEOUT), ) .await?; } info!( "Deleting block {:?}, offload finished ({} / {})", hash, need_nodes.len(), who.len() ); self.mutation_lock .lock() .await .delete_if_unneeded(hash, self) .await?; } if needed && !exists { // TODO find a way to not do this if they are sending it to us // Let's suppose this isn't an issue for now with the BLOCK_RW_TIMEOUT delay // between the RC being incremented and this part being called. let block_data = self.rpc_get_block(hash).await?; self.write_block(hash, &block_data[..]).await?; } Ok(()) } async fn for_each_file( &self, state: State, mut f: F, must_exit: &watch::Receiver, ) -> Result<(), Error> where F: FnMut(State, Hash) -> Fut + Send, Fut: Future> + 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, ) -> BoxFuture<'a, Result> where F: FnMut(State, Hash) -> Fut + Send, Fut: Future> + 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?; 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() } /// Verify integrity of each block on disk. Use `speed_limit` to limit the load generated by /// this function. pub async fn verify_data_store_integrity( &self, must_exit: &watch::Receiver, speed_limit: Option, ) -> Result<(), Error> { let last_refill = Instant::now(); let token_left = speed_limit.unwrap_or(0); self.for_each_file( (last_refill, token_left), move |(last_refill, token_left), hash| { async move { let len = match self.read_block(&hash).await { Ok(BlockRpc::PutBlock(PutBlockMessage { data, .. })) => data.len(), Ok(_) => unreachable!(), Err(_) => 0, // resync and warn message made by read_block if necessary }; if let Some(speed_limit) = speed_limit { // throttling logic if let Some(t) = token_left.checked_sub(len) { // token bucket not empty yet Ok((last_refill, t)) } else { // token bucket empty. Sleep and refill tokio::time::sleep_until(last_refill + Duration::from_secs(1)).await; Ok((Instant::now(), speed_limit)) } } else { Ok((last_refill, token_left)) // actually not used } } }, must_exit, ) .await } } #[async_trait] impl EndpointHandler for BlockManager { async fn handle( self: &Arc, message: &BlockRpc, _from: NodeID, ) -> Result { match message { BlockRpc::PutBlock(m) => self.write_block(&m.hash, &m.data).await, BlockRpc::GetBlock(h) => self.read_block(h).await, BlockRpc::NeedBlockQuery(h) => self.need_block(h).await.map(BlockRpc::NeedBlockReply), _ => Err(Error::BadRpc("Unexpected RPC message".to_string())), } } } struct BlockStatus { exists: bool, needed: bool, } impl BlockManagerLocked { async fn check_block_status( &self, hash: &Hash, mgr: &BlockManager, ) -> Result { let path = mgr.block_path(hash); let exists = fs::metadata(&path).await.is_ok(); let needed = mgr.get_block_rc(hash)? > 0; Ok(BlockStatus { exists, needed }) } async fn write_block( &self, hash: &Hash, data: &[u8], mgr: &BlockManager, ) -> Result { let mut path = mgr.block_dir(hash); fs::create_dir_all(&path).await?; path.push(hex::encode(hash)); if fs::metadata(&path).await.is_ok() { return Ok(BlockRpc::Ok); } let mut path2 = path.clone(); path2.set_extension("tmp"); let mut f = fs::File::create(&path2).await?; f.write_all(data).await?; drop(f); fs::rename(path2, path).await?; 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 path = mgr.block_path(hash); let mut path2 = path.clone(); path2.set_extension("corrupted"); fs::rename(path, path2).await?; mgr.put_to_resync(hash, Duration::from_millis(0))?; 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 { let path = mgr.block_path(hash); fs::remove_file(path).await?; } Ok(()) } } fn u64_from_be_bytes>(bytes: T) -> u64 { assert!(bytes.as_ref().len() == 8); let mut x8 = [0u8; 8]; x8.copy_from_slice(bytes.as_ref()); u64::from_be_bytes(x8) }