garage/src/block/manager.rs
2023-03-09 17:08:47 +00:00

787 lines
21 KiB
Rust

use std::path::PathBuf;
use std::pin::Pin;
use std::sync::Arc;
use std::time::Duration;
use arc_swap::ArcSwapOption;
use async_trait::async_trait;
use bytes::Bytes;
use rand::prelude::*;
use serde::{Deserialize, Serialize};
use futures::Stream;
use futures_util::stream::StreamExt;
use tokio::fs;
use tokio::io::{AsyncReadExt, AsyncWriteExt, BufReader};
use tokio::sync::{mpsc, Mutex, MutexGuard};
use opentelemetry::{
trace::{FutureExt as OtelFutureExt, TraceContextExt, Tracer},
Context,
};
use garage_rpc::rpc_helper::netapp::stream::{stream_asyncread, ByteStream};
use garage_db as db;
use garage_util::background::{vars, BackgroundRunner};
use garage_util::data::*;
use garage_util::error::*;
use garage_util::metrics::RecordDuration;
use garage_util::persister::PersisterShared;
use garage_util::time::msec_to_rfc3339;
use garage_rpc::rpc_helper::OrderTag;
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;
// 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, Option<OrderTag>),
/// Message to send a block of data, either because requested, of for first delivery of new
/// block
PutBlock {
hash: Hash,
header: DataBlockHeader,
},
/// 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>; 256],
pub(crate) rc: BlockRc,
pub resync: BlockResyncManager,
pub(crate) system: Arc<System>,
pub(crate) endpoint: Arc<Endpoint<BlockRpc, Self>>,
pub(crate) metrics: BlockManagerMetrics,
pub scrub_persister: PersisterShared<ScrubWorkerPersisted>,
tx_scrub_command: ArcSwapOption<mpsc::Sender<ScrubWorkerCommand>>,
}
#[derive(Serialize, Deserialize, Clone, Debug)]
pub struct BlockResyncErrorInfo {
pub hash: Hash,
pub refcount: u64,
pub error_count: u64,
pub last_try: u64,
pub next_try: u64,
}
// 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 metrics = BlockManagerMetrics::new(
compression_level,
rc.rc.clone(),
resync.queue.clone(),
resync.errors.clone(),
);
let scrub_persister = PersisterShared::new(&system.metadata_dir, "scrub_info");
let block_manager = Arc::new(Self {
replication,
data_dir,
compression_level,
mutation_lock: [(); 256].map(|_| Mutex::new(BlockManagerLocked())),
rc,
resync,
system,
endpoint,
metrics,
scrub_persister,
tx_scrub_command: ArcSwapOption::new(None),
});
block_manager.endpoint.set_handler(block_manager.clone());
block_manager.scrub_persister.set_with(|_| ()).unwrap();
block_manager
}
pub fn spawn_workers(self: &Arc<Self>, bg: &BackgroundRunner) {
// Spawn a bunch of resync workers
for index in 0..MAX_RESYNC_WORKERS {
let worker = ResyncWorker::new(index, self.clone());
bg.spawn_worker(worker);
}
// Spawn scrub worker
let (scrub_tx, scrub_rx) = mpsc::channel(1);
self.tx_scrub_command.store(Some(Arc::new(scrub_tx)));
bg.spawn_worker(ScrubWorker::new(
self.clone(),
scrub_rx,
self.scrub_persister.clone(),
));
}
pub fn register_bg_vars(&self, vars: &mut vars::BgVars) {
self.resync.register_bg_vars(vars);
vars.register_rw(
&self.scrub_persister,
"scrub-tranquility",
|p| p.get_with(|x| x.tranquility),
|p, tranquility| p.set_with(|x| x.tranquility = tranquility),
);
vars.register_ro(&self.scrub_persister, "scrub-last-completed", |p| {
p.get_with(|x| msec_to_rfc3339(x.time_last_complete_scrub))
});
vars.register_ro(&self.scrub_persister, "scrub-next-run", |p| {
p.get_with(|x| msec_to_rfc3339(x.time_next_run_scrub))
});
vars.register_ro(&self.scrub_persister, "scrub-corruptions_detected", |p| {
p.get_with(|x| x.corruptions_detected)
});
}
/// Ask nodes that might have a (possibly compressed) block for it
/// Return it as a stream with a header
async fn rpc_get_raw_block_streaming(
&self,
hash: &Hash,
order_tag: Option<OrderTag>,
) -> Result<(DataBlockHeader, ByteStream), 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;
}
};
return Ok((header, stream));
}
_ = 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 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 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,
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: Bytes) -> Result<(), Error> {
let who = self.replication.write_nodes(&hash);
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[..],
put_block_rpc,
RequestStrategy::with_priority(PRIO_NORMAL | PRIO_SECONDARY)
.with_quorum(self.replication.write_quorum()),
)
.await?;
Ok(())
}
/// 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_fast_len(&self) -> Result<Option<usize>, Error> {
Ok(self.rc.rc.fast_len()?)
}
/// Send command to start/stop/manager scrub worker
pub async fn send_scrub_command(&self, cmd: ScrubWorkerCommand) -> Result<(), Error> {
let tx = self.tx_scrub_command.load();
let tx = tx.as_ref().ok_or_message("scrub worker is not running")?;
tx.send(cmd).await.ok_or_message("send error")?;
Ok(())
}
/// Get the reference count of a block
pub fn get_block_rc(&self, hash: &Hash) -> Result<u64, Error> {
Ok(self.rc.get_block_rc(hash)?.as_u64())
}
/// List all resync errors
pub fn list_resync_errors(&self) -> Result<Vec<BlockResyncErrorInfo>, Error> {
let mut blocks = Vec::with_capacity(self.resync.errors.len());
for ent in self.resync.errors.iter()? {
let (hash, cnt) = ent?;
let cnt = ErrorCounter::decode(&cnt);
blocks.push(BlockResyncErrorInfo {
hash: Hash::try_from(&hash).unwrap(),
refcount: 0,
error_count: cnt.errors,
last_try: cnt.last_try,
next_try: cnt.next_try(),
});
}
for block in blocks.iter_mut() {
block.refcount = self.get_block_rc(&block.hash)?;
}
Ok(blocks)
}
//// ----- 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 * 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: &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 ----
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
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;
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(())
}
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
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)
.await?;
self.metrics
.bytes_read
.add(data.inner_buffer().len() as u64);
Ok(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 * self.system.rpc.rpc_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.into())
} else {
DataBlock::Plain(data.into())
};
if data.verify(*hash).is_err() {
self.metrics.corruption_counter.add(1);
self.lock_mutate(hash)
.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.lock_mutate(hash)
.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.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();
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 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
}
}
#[async_trait]
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))),
}
}
}
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<(), 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(()),
(Ok(false), false) => return 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 path_tmp = path.clone();
let tmp_extension = format!("tmp{}", hex::encode(thread_rng().gen::<[u8; 4]>()));
path_tmp.set_extension(tmp_extension);
let mut delete_on_drop = DeleteOnDrop(Some(path_tmp.clone()));
let mut f = fs::File::create(&path_tmp).await?;
f.write_all(data).await?;
f.sync_all().await?;
drop(f);
fs::rename(path_tmp, path).await?;
delete_on_drop.cancel();
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(())
}
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(())
}
}
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")?);
}
Ok(parts
.iter()
.map(|x| &x[..])
.collect::<Vec<_>>()
.concat()
.into())
}
struct DeleteOnDrop(Option<PathBuf>);
impl DeleteOnDrop {
fn cancel(&mut self) {
drop(self.0.take());
}
}
impl Drop for DeleteOnDrop {
fn drop(&mut self) {
if let Some(path) = self.0.take() {
tokio::spawn(async move {
if let Err(e) = fs::remove_file(&path).await {
debug!("DeleteOnDrop failed for {}: {}", path.display(), e);
}
});
}
}
}