aboutsummaryrefslogtreecommitdiff
path: root/src/model/block.rs
blob: 699ff32d3f8b975c1f5178e69b37994b83d79ae1 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
use std::path::PathBuf;
use std::sync::Arc;
use std::time::Duration;

use arc_swap::ArcSwapOption;
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 zstd::stream::{decode_all as zstd_decode, Encoder};

use garage_util::data::*;
use garage_util::error::Error;
use garage_util::time::*;

use garage_rpc::membership::System;
use garage_rpc::rpc_client::*;
use garage_rpc::rpc_server::*;

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 = 1;

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 Message {
	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: BlockData,
	},
	/// 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),
}

/// A possibly compressed block of data
#[derive(Debug, Serialize, Deserialize)]
pub enum BlockData {
	Plain(#[serde(with = "serde_bytes")] Vec<u8>),
	Compressed(#[serde(with = "serde_bytes")] Vec<u8>),
}

impl BlockData {
	pub fn is_compressed(&self) -> bool {
		match self {
			BlockData::Plain(_) => false,
			BlockData::Compressed(_) => true,
		}
	}

	pub fn buffer(&self) -> &Vec<u8> {
		match self {
			BlockData::Plain(b) => b,
			BlockData::Compressed(b) => b,
		}
	}
}

impl RpcMessage for Message {}

/// 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,
	/// Lock to prevent concurrent edition of the directory
	pub data_dir_lock: Mutex<()>,

	rc: sled::Tree,

	resync_queue: sled::Tree,
	resync_notify: Notify,

	system: Arc<System>,
	rpc_client: Arc<RpcClient<Message>>,
	pub(crate) garage: ArcSwapOption<Garage>,
}

impl BlockManager {
	pub fn new(
		db: &sled::Db,
		data_dir: PathBuf,
		replication: TableShardedReplication,
		system: Arc<System>,
		rpc_server: &mut RpcServer,
	) -> Arc<Self> {
		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 rpc_path = "block_manager";
		let rpc_client = system.rpc_client::<Message>(rpc_path);

		let block_manager = Arc::new(Self {
			replication,
			data_dir,
			data_dir_lock: Mutex::new(()),
			rc,
			resync_queue,
			resync_notify: Notify::new(),
			system,
			rpc_client,
			garage: ArcSwapOption::from(None),
		});
		block_manager
			.clone()
			.register_handler(rpc_server, rpc_path.into());
		block_manager
	}

	fn register_handler(self: Arc<Self>, rpc_server: &mut RpcServer, path: String) {
		let self2 = self.clone();
		rpc_server.add_handler::<Message, _, _>(path, move |msg, _addr| {
			let self2 = self2.clone();
			async move { self2.handle(&msg).await }
		});

		let self2 = self.clone();
		self.rpc_client
			.set_local_handler(self.system.id, move |msg| {
				let self2 = self2.clone();
				async move { self2.handle(&msg).await }
			});
	}

	async fn handle(self: Arc<Self>, msg: &Message) -> Result<Message, Error> {
		match msg {
			Message::PutBlock { hash, data } => self.write_block(&hash, &data).await,
			Message::GetBlock(h) => self.read_block(h).await,
			Message::NeedBlockQuery(h) => self.need_block(h).await.map(Message::NeedBlockReply),
			_ => Err(Error::BadRPC(format!("Unexpected RPC message"))),
		}
	}

	pub fn spawn_background_worker(self: Arc<Self>) {
		// Launch 2 simultaneous workers for background resync loop preprocessing <= TODO actually this
		// launches only one worker with current value of BACKGROUND_WORKERS
		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)
				});
			});
		}
	}

	/// Write a block to disk
	pub async fn write_block(&self, hash: &Hash, data: &BlockData) -> Result<Message, Error> {
		let mut path = self.block_dir(hash);

		let _lock = self.data_dir_lock.lock().await;

		let clean_plain = match self.is_block_compressed(hash).await {
			Ok(true) => return Ok(Message::Ok),
			Ok(false) if !data.is_compressed() => return Ok(Message::Ok), // we have a plain block, and the provided block is not compressed either
			Ok(false) => true,
			Err(_) => false,
		};

		fs::create_dir_all(&path).await?;
		path.push(hex::encode(hash));

		if data.is_compressed() {
			path.set_extension("zst");
		}

		let buffer = data.buffer();

		let mut f = fs::File::create(path.clone()).await?;
		f.write_all(&buffer).await?;

		if clean_plain {
			path.set_extension("");
			fs::remove_file(path).await?;
		}
		drop(f);

		Ok(Message::Ok)
	}

	/// Read block from disk, verifying it's integrity
	pub async fn read_block(&self, hash: &Hash) -> Result<Message, Error> {
		let mut path = self.block_path(hash);

		let mut data = vec![];
		let block = match self.is_block_compressed(hash).await {
			Ok(false) => {
				let f = fs::File::open(&path).await;
				f.map(|f| (f, false)).map_err(Into::into)
			}
			Ok(true) => {
				path.set_extension("zst");
				let f = fs::File::open(&path).await;
				f.map(|f| (f, true)).map_err(Into::into)
			}
			Err(e) => Err(e),
		};
		let (mut f, compressed) = match block {
			Ok(ok) => ok,
			e => {
				// Not found but maybe we should have had it ??
				self.put_to_resync(hash, Duration::from_millis(0))?;
				e?
			}
		};
		f.read_to_end(&mut data).await?;
		drop(f);

		let sum_ok = if compressed {
			zstd_check_checksum(&data[..])
		} else {
			blake2sum(&data[..]) == *hash
		};
		if !sum_ok {
			let _lock = self.data_dir_lock.lock().await;
			warn!(
				"Block {:?} is corrupted. Renaming to .corrupted and resyncing.",
				hash
			);
			let mut path2 = path.clone();
			path2.set_extension("corrupted");
			fs::rename(path, path2).await?;
			self.put_to_resync(&hash, Duration::from_millis(0))?;
			return Err(Error::CorruptData(*hash));
		}

		if compressed {
			Ok(Message::PutBlock {
				hash: *hash,
				data: BlockData::Compressed(data),
			})
		} else {
			Ok(Message::PutBlock {
				hash: *hash,
				data: BlockData::Plain(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 needed = self
			.rc
			.get(hash.as_ref())?
			.map(|x| u64_from_be_bytes(x) > 0)
			.unwrap_or(false);
		if needed {
			let exists = self.is_block_compressed(hash).await.is_ok();
			Ok(!exists)
		} else {
			Ok(false)
		}
	}

	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)
	}

	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
	}
	fn block_path(&self, hash: &Hash) -> PathBuf {
		let mut path = self.block_dir(hash);
		path.push(hex::encode(hash.as_ref()));
		path
	}

	/// 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(())
	}

	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<Self>, mut must_exit: watch::Receiver<bool>) {
		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<bool>) -> 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 lock = self.data_dir_lock.lock().await;

		let path = self.block_path(hash);

		let exists = self.is_block_compressed(hash).await.is_ok();
		let needed = self
			.rc
			.get(hash.as_ref())?
			.map(|x| u64_from_be_bytes(x) > 0)
			.unwrap_or(false);

		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(format!("Not trying to offload block because we don't have a quorum of nodes to write to")));
			}
			who.retain(|id| *id != self.system.id);

			let msg = Arc::new(Message::NeedBlockQuery(*hash));
			let who_needs_fut = who.iter().map(|to| {
				self.rpc_client
					.call_arc(*to, msg.clone(), 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? {
					Message::NeedBlockReply(needed) => {
						if needed {
							need_nodes.push(*node);
						}
					}
					_ => {
						return Err(Error::Message(format!(
							"Unexpected response to NeedBlockQuery RPC"
						)));
					}
				}
			}

			if need_nodes.len() > 0 {
				trace!(
					"Block {:?} needed by {} nodes, sending",
					hash,
					need_nodes.len()
				);

				let put_block_message = self.read_block(hash).await?;
				self.rpc_client
					.try_call_many(
						&need_nodes[..],
						put_block_message,
						RequestStrategy::with_quorum(need_nodes.len())
							.with_timeout(BLOCK_RW_TIMEOUT),
					)
					.await?;
			}
			info!(
				"Deleting block {:?}, offload finished ({} / {})",
				hash,
				need_nodes.len(),
				who.len()
			);

			fs::remove_file(path).await?;
		}

		if needed && !exists {
			drop(lock);

			// 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 = self.rpc_get_raw_block(&hash).await?;
			self.write_block(hash, &block).await?;
		}

		Ok(())
	}

	async fn rpc_get_raw_block(&self, hash: &Hash) -> Result<BlockData, Error> {
		let who = self.replication.read_nodes(&hash);
		let resps = self
			.rpc_client
			.try_call_many(
				&who[..],
				Message::GetBlock(*hash),
				RequestStrategy::with_quorum(1)
					.with_timeout(BLOCK_RW_TIMEOUT)
					.interrupt_after_quorum(true),
			)
			.await?;

		for resp in resps {
			match resp {
				Message::PutBlock { data, .. } => return Ok(data),
				_ => {}
			}
		}
		Err(Error::Message(format!(
			"Unable to read block {:?}: no valid blocks returned",
			hash
		)))
	}

	/// 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
			.and_then(|data| match data {
				BlockData::Plain(data) => Ok(data),
				BlockData::Compressed(data) => {
					zstd_decode(&data[..]).map_err(|_| Error::CorruptData(*hash))
				}
			})
	}

	/// Send block to nodes that should have it
	pub async fn rpc_put_block(&self, hash: Hash, data: Vec<u8>) -> Result<(), Error> {
		let garage = self.garage.load_full().unwrap();
		let compressed = zstd_encode(&data[..], garage.config.compression_level);
		let message = if compressed.is_ok() && compressed.as_ref().unwrap().len() < data.len() {
			Message::PutBlock {
				hash,
				data: BlockData::Compressed(compressed.unwrap()),
			}
		} else {
			Message::PutBlock {
				hash,
				data: BlockData::Plain(data),
			}
		};
		let who = self.replication.write_nodes(&hash);
		self.rpc_client
			.try_call_many(
				&who[..],
				message,
				RequestStrategy::with_quorum(self.replication.write_quorum())
					.with_timeout(BLOCK_RW_TIMEOUT),
			)
			.await?;
		Ok(())
	}

	pub async fn repair_data_store(&self, must_exit: &watch::Receiver<bool>) -> Result<(), Error> {
		// 1. Repair blocks from RC table
		let garage = self.garage.load_full().unwrap();
		let mut last_hash = None;
		let mut i = 0usize;
		for entry in garage.block_ref_table.data.store.iter() {
			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))?;
			}
			i += 1;
			if i & 0xFF == 0 && *must_exit.borrow() {
				return Ok(());
			}
		}

		// 2. Repair blocks actually on disk
		self.repair_aux_read_dir_rec(&self.data_dir, must_exit)
			.await?;

		Ok(())
	}

	fn repair_aux_read_dir_rec<'a>(
		&'a self,
		path: &'a PathBuf,
		must_exit: &'a watch::Receiver<bool>,
	) -> BoxFuture<'a, Result<(), Error>> {
		// 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.
		async move {
			let mut ls_data_dir = fs::read_dir(path).await?;
			loop {
				let data_dir_ent = ls_data_dir.next_entry().await?;
				let data_dir_ent = match data_dir_ent {
					Some(x) => x,
					None => break,
				};
				let name = data_dir_ent.file_name();
				let name = match name.into_string() {
					Ok(x) => x,
					Err(_) => continue,
				};
				let ent_type = data_dir_ent.file_type().await?;

				if name.len() == 2 && hex::decode(&name).is_ok() && ent_type.is_dir() {
					self.repair_aux_read_dir_rec(&data_dir_ent.path(), must_exit)
						.await?;
				} else if name.len() == 64 {
					let hash_bytes = match hex::decode(&name) {
						Ok(h) => h,
						Err(_) => continue,
					};
					let mut hash = [0u8; 32];
					hash.copy_from_slice(&hash_bytes[..]);
					self.put_to_resync(&hash.into(), Duration::from_secs(0))?;
				}

				if *must_exit.borrow() {
					break;
				}
			}
			Ok(())
		}
		.boxed()
	}

	/// Get lenght of resync queue
	pub fn resync_queue_len(&self) -> usize {
		self.resync_queue.len()
	}

	pub fn rc_len(&self) -> usize {
		self.rc.len()
	}
}

fn u64_from_be_bytes<T: AsRef<[u8]>>(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)
}

fn zstd_check_checksum<R: std::io::Read>(source: R) -> bool {
	zstd::stream::copy_decode(source, std::io::sink()).is_ok()
}

fn zstd_encode<R: std::io::Read>(mut source: R, level: i32) -> std::io::Result<Vec<u8>> {
	let mut result = Vec::<u8>::new();
	let mut encoder = Encoder::new(&mut result, level)?;
	encoder.include_checksum(true)?;
	std::io::copy(&mut source, &mut encoder)?;
	encoder.finish()?;
	Ok(result)
}