block manager: skeleton for multi-hdd support

7 files changed, 277 insertions, 90 deletions

diff --git a/src/block/layout.rs b/src/block/layout.rs
new file mode 100644
index 00000000..cbc326d8
--- /dev/null
+++ b/src/block/layout.rs
@@ -0,0 +1,57 @@
+use std::path::PathBuf;
+
+use serde::{Deserialize, Serialize};
+
+use garage_util::config::DataDirEnum;
+use garage_util::data::Hash;
+use garage_util::migrate::*;
+
+pub const DRIVE_NPART: usize = 1024;
+
+#[derive(Serialize, Deserialize, Debug, Clone)]
+pub(crate) struct DataLayout {
+	pub(crate) data_dirs: Vec<DataDir>,
+	pub(crate) partitions: Vec<Partition>,
+}
+
+#[derive(Serialize, Deserialize, Debug, Clone)]
+pub(crate) struct DataDir {
+	pub(crate) path: PathBuf,
+	pub(crate) state: DataDirState,
+}
+
+#[derive(Serialize, Deserialize, Debug, Clone)]
+pub(crate) enum DataDirState {
+	Active { capacity: u64 },
+	ReadOnly,
+}
+
+#[derive(Serialize, Deserialize, Debug, Clone)]
+pub(crate) struct Partition {
+	pub(crate) prim: usize,
+	pub(crate) sec: Vec<usize>,
+}
+
+impl DataLayout {
+	pub(crate) fn initialize(dirs: &DataDirEnum) -> Self {
+		todo!()
+	}
+
+	pub(crate) fn update(&mut self, dirs: &DataDirEnum) -> Self {
+		todo!()
+	}
+
+	pub(crate) fn data_dir(&self, hash: &Hash) -> PathBuf {
+		todo!()
+		/*
+		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
+		*/
+	}
+}
+
+impl InitialFormat for DataLayout {
+	const VERSION_MARKER: &'static [u8] = b"G09bmdl";
+}
diff --git a/src/block/lib.rs b/src/block/lib.rs
index d2814f77..c9ff2845 100644
--- a/src/block/lib.rs
+++ b/src/block/lib.rs
@@ -6,5 +6,6 @@ pub mod repair;
 pub mod resync;
 
 mod block;
+mod layout;
 mod metrics;
 mod rc;
diff --git a/src/block/manager.rs b/src/block/manager.rs
index c7e4cd03..18a2686e 100644
--- a/src/block/manager.rs
+++ b/src/block/manager.rs
@@ -25,10 +25,11 @@ use garage_rpc::rpc_helper::netapp::stream::{stream_asyncread, ByteStream};
 use garage_db as db;
 
 use garage_util::background::{vars, BackgroundRunner};
+use garage_util::config::DataDirEnum;
 use garage_util::data::*;
 use garage_util::error::*;
 use garage_util::metrics::RecordDuration;
-use garage_util::persister::PersisterShared;
+use garage_util::persister::{Persister, PersisterShared};
 use garage_util::time::msec_to_rfc3339;
 
 use garage_rpc::rpc_helper::OrderTag;
@@ -38,6 +39,7 @@ use garage_rpc::*;
 use garage_table::replication::{TableReplication, TableShardedReplication};
 
 use crate::block::*;
+use crate::layout::*;
 use crate::metrics::*;
 use crate::rc::*;
 use crate::repair::*;
@@ -77,8 +79,11 @@ impl Rpc for BlockRpc {
 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,
+
+	/// Directory/ies in which block are stored
+	pub data_dir: DataDirEnum,
+	/// Data layout
+	pub(crate) data_layout: DataLayout,
 
 	data_fsync: bool,
 	compression_level: Option<i32>,
@@ -114,12 +119,22 @@ struct BlockManagerLocked();
 impl BlockManager {
 	pub fn new(
 		db: &db::Db,
-		data_dir: PathBuf,
+		data_dir: DataDirEnum,
 		data_fsync: bool,
 		compression_level: Option<i32>,
 		replication: TableShardedReplication,
 		system: Arc<System>,
 	) -> Arc<Self> {
+		let layout_persister: Persister<DataLayout> =
+			Persister::new(&system.metadata_dir, "data_layout");
+		let data_layout = match layout_persister.load() {
+			Ok(mut layout) => {
+				layout.update(&data_dir);
+				layout
+			}
+			Err(_) => DataLayout::initialize(&data_dir),
+		};
+
 		let rc = db
 			.open_tree("block_local_rc")
 			.expect("Unable to open block_local_rc tree");
@@ -143,6 +158,7 @@ impl BlockManager {
 		let block_manager = Arc::new(Self {
 			replication,
 			data_dir,
+			data_layout,
 			data_fsync,
 			compression_level,
 			mutation_lock: [(); 256].map(|_| Mutex::new(BlockManagerLocked())),
@@ -586,10 +602,7 @@ impl BlockManager {
 
 	/// 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
+		self.data_layout.data_dir(hash)
 	}
 
 	/// Utility: give the full path where a block should be found, minus extension if block is
diff --git a/src/block/repair.rs b/src/block/repair.rs
index 71093d69..d5e2e168 100644
--- a/src/block/repair.rs
+++ b/src/block/repair.rs
@@ -17,6 +17,7 @@ use garage_util::persister::PersisterShared;
 use garage_util::time::*;
 use garage_util::tranquilizer::Tranquilizer;
 
+use crate::layout::*;
 use crate::manager::*;
 
 // Full scrub every 25 days with a random element of 10 days mixed in below
@@ -136,7 +137,7 @@ impl Worker for RepairWorker {
 				// 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? {
+				if let Some((_path, hash)) = bi.next().await? {
 					self.manager
 						.resync
 						.put_to_resync(&hash, Duration::from_secs(0))?;
@@ -376,7 +377,7 @@ impl Worker for ScrubWorker {
 		match &mut self.work {
 			ScrubWorkerState::Running(bsi) => {
 				self.tranquilizer.reset();
-				if let Some(hash) = bsi.next().await? {
+				if let Some((_path, hash)) = bsi.next().await? {
 					match self.manager.read_block(&hash).await {
 						Err(Error::CorruptData(_)) => {
 							error!("Found corrupt data block during scrub: {:?}", hash);
@@ -447,100 +448,166 @@ impl Worker for ScrubWorker {
 // UTILITY FOR ENUMERATING THE BLOCK STORE
 // ---- ---- ----
 
+const PROGRESS_FP: u64 = 1_000_000_000;
+
 struct BlockStoreIterator {
-	path: Vec<ReadingDir>,
+	todo: Vec<BsiTodo>,
 }
 
-enum ReadingDir {
-	Pending(PathBuf),
-	Read {
-		subpaths: Vec<fs::DirEntry>,
-		pos: usize,
+enum BsiTodo {
+	Directory {
+		path: PathBuf,
+		progress_min: u64,
+		progress_max: u64,
+	},
+	File {
+		path: PathBuf,
+		filename: String,
+		progress: u64,
 	},
 }
 
 impl BlockStoreIterator {
 	fn new(manager: &BlockManager) -> Self {
-		let root_dir = manager.data_dir.clone();
-		Self {
-			path: vec![ReadingDir::Pending(root_dir)],
+		let min_cap = manager
+			.data_layout
+			.data_dirs
+			.iter()
+			.filter_map(|x| match x.state {
+				DataDirState::Active { capacity } => Some(capacity),
+				_ => None,
+			})
+			.min()
+			.unwrap_or(0);
+
+		let sum_cap = manager
+			.data_layout
+			.data_dirs
+			.iter()
+			.map(|x| match x.state {
+				DataDirState::Active { capacity } => capacity,
+				_ => min_cap, // approximation
+			})
+			.sum::<u64>() as u128;
+
+		let mut cum_cap = 0;
+		let mut todo = vec![];
+		for dir in manager.data_layout.data_dirs.iter() {
+			let cap = match dir.state {
+				DataDirState::Active { capacity } => capacity,
+				_ => min_cap,
+			};
+
+			let progress_min = ((cum_cap as u128 * PROGRESS_FP as u128) / (sum_cap as u128)) as u64;
+			let progress_max =
+				(((cum_cap + cap) as u128 * PROGRESS_FP as u128) / (sum_cap as u128)) as u64;
+			cum_cap += cap;
+
+			todo.push(BsiTodo::Directory {
+				path: dir.path.clone(),
+				progress_min,
+				progress_max,
+			});
 		}
+		// entries are processed back-to-front (because of .pop()),
+		// so reverse entries to process them in increasing progress bounds
+		todo.reverse();
+
+		let ret = Self { todo };
+		debug_assert!(ret.progress_invariant());
+
+		ret
 	}
 
 	/// 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
-		}
+		self.todo
+			.last()
+			.map(|x| match x {
+				BsiTodo::Directory { progress_min, .. } => *progress_min,
+				BsiTodo::File { progress, .. } => *progress,
+			})
+			.map(|x| x as f32 / PROGRESS_FP as f32)
+			.unwrap_or(1.0)
 	}
 
-	async fn next(&mut self) -> Result<Option<Hash>, Error> {
+	async fn next(&mut self) -> Result<Option<(PathBuf, Hash)>, Error> {
 		loop {
-			let last_path = match self.path.last_mut() {
+			match self.todo.pop() {
 				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!(),
-			};
+				Some(BsiTodo::Directory {
+					path,
+					progress_min,
+					progress_max,
+				}) => {
+					let istart = self.todo.len();
+
+					let mut reader = fs::read_dir(&path).await?;
+					while let Some(ent) = reader.next_entry().await? {
+						let name = if let Ok(n) = ent.file_name().into_string() {
+							n
+						} else {
+							continue;
+						};
+						let ft = ent.file_type().await?;
+						if ft.is_dir() && hex::decode(&name).is_ok() {
+							self.todo.push(BsiTodo::Directory {
+								path: ent.path(),
+								progress_min: 0,
+								progress_max: 0,
+							});
+						} else if ft.is_file() {
+							self.todo.push(BsiTodo::File {
+								path: ent.path(),
+								filename: name,
+								progress: 0,
+							});
+						}
+					}
 
-			let data_dir_ent = match subpaths.get(*pos) {
-				None => {
-					self.path.pop();
-					continue;
-				}
-				Some(ent) => {
-					*pos += 1;
-					ent
+					let count = self.todo.len() - istart;
+					for (i, ent) in self.todo[istart..].iter_mut().enumerate() {
+						let p1 = progress_min
+							+ ((progress_max - progress_min) * i as u64) / count as u64;
+						let p2 = progress_min
+							+ ((progress_max - progress_min) * (i + 1) as u64) / count as u64;
+						match ent {
+							BsiTodo::Directory {
+								progress_min,
+								progress_max,
+								..
+							} => {
+								*progress_min = p1;
+								*progress_max = p2;
+							}
+							BsiTodo::File { progress, .. } => {
+								*progress = p1;
+							}
+						}
+					}
+					self.todo[istart..].reverse();
+					debug_assert!(self.progress_invariant());
 				}
-			};
-
-			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()));
+				Some(BsiTodo::File { path, filename, .. }) => {
+					let filename = filename.strip_suffix(".zst").unwrap_or(&filename);
+					if filename.len() == 64 {
+						if let Ok(h) = hex::decode(filename) {
+							let mut hash = [0u8; 32];
+							hash.copy_from_slice(&h);
+							return Ok(Some((path, hash.into())));
+						}
+					}
 				}
 			}
 		}
 	}
+
+	fn progress_invariant(&self) -> bool {
+		let iter = self.todo.iter().map(|x| match x {
+			BsiTodo::Directory { progress_min, .. } => progress_min,
+			BsiTodo::File { progress, .. } => progress,
+		});
+		let iter_1 = iter.clone().skip(1);
+		iter.zip(iter_1).all(|(prev, next)| prev >= next)
+	}
 }
diff --git a/src/model/garage.rs b/src/model/garage.rs
index 981430fb..d6eebfb0 100644
--- a/src/model/garage.rs
+++ b/src/model/garage.rs
@@ -92,8 +92,22 @@ impl Garage {
 		// Create meta dir and data dir if they don't exist already
 		std::fs::create_dir_all(&config.metadata_dir)
 			.ok_or_message("Unable to create Garage metadata directory")?;
-		std::fs::create_dir_all(&config.data_dir)
-			.ok_or_message("Unable to create Garage data directory")?;
+		match &config.data_dir {
+			DataDirEnum::Single(data_dir) => {
+				std::fs::create_dir_all(data_dir).ok_or_message(format!(
+					"Unable to create Garage data directory: {}",
+					data_dir.to_string_lossy()
+				))?;
+			}
+			DataDirEnum::Multiple(data_dirs) => {
+				for dir in data_dirs {
+					std::fs::create_dir_all(&dir.path).ok_or_message(format!(
+						"Unable to create Garage data directory: {}",
+						dir.path.to_string_lossy()
+					))?;
+				}
+			}
+		}
 
 		info!("Opening database...");
 		let mut db_path = config.metadata_dir.clone();
diff --git a/src/rpc/system.rs b/src/rpc/system.rs
index 1675e70e..c5751d5d 100644
--- a/src/rpc/system.rs
+++ b/src/rpc/system.rs
@@ -22,9 +22,9 @@ use netapp::peering::fullmesh::FullMeshPeeringStrategy;
 use netapp::util::parse_and_resolve_peer_addr_async;
 use netapp::{NetApp, NetworkKey, NodeID, NodeKey};
 
-use garage_util::config::Config;
 #[cfg(feature = "kubernetes-discovery")]
 use garage_util::config::KubernetesDiscoveryConfig;
+use garage_util::config::{Config, DataDirEnum};
 use garage_util::data::*;
 use garage_util::error::*;
 use garage_util::persister::Persister;
@@ -119,7 +119,7 @@ pub struct System {
 	/// Path to metadata directory
 	pub metadata_dir: PathBuf,
 	/// Path to data directory
-	pub data_dir: PathBuf,
+	pub data_dir: DataDirEnum,
 }
 
 #[derive(Debug, Clone, Serialize, Deserialize)]
@@ -890,7 +890,12 @@ impl NodeStatus {
 		}
 	}
 
-	fn update_disk_usage(&mut self, meta_dir: &Path, data_dir: &Path, metrics: &SystemMetrics) {
+	fn update_disk_usage(
+		&mut self,
+		meta_dir: &Path,
+		data_dir: &DataDirEnum,
+		metrics: &SystemMetrics,
+	) {
 		use systemstat::{Platform, System};
 		let mounts = System::new().mounts().unwrap_or_default();
 
@@ -903,7 +908,17 @@ impl NodeStatus {
 		};
 
 		self.meta_disk_avail = mount_avail(meta_dir);
-		self.data_disk_avail = mount_avail(data_dir);
+		self.data_disk_avail = match data_dir {
+			DataDirEnum::Single(dir) => mount_avail(dir),
+			DataDirEnum::Multiple(dirs) => {
+				dirs.iter()
+					.map(|d| mount_avail(&d.path))
+					.fold(Some((0, 0)), |acc, cur| match (acc, cur) {
+						(Some((x, y)), Some((a, b))) => Some((x + a, y + b)),
+						_ => None,
+					})
+			}
+		};
 
 		if let Some((avail, total)) = self.meta_disk_avail {
 			metrics
diff --git a/src/util/config.rs b/src/util/config.rs
index eeb17e0e..9d00fe82 100644
--- a/src/util/config.rs
+++ b/src/util/config.rs
@@ -13,7 +13,7 @@ pub struct Config {
 	/// Path where to store metadata. Should be fast, but low volume
 	pub metadata_dir: PathBuf,
 	/// Path where to store data. Can be slower, but need higher volume
-	pub data_dir: PathBuf,
+	pub data_dir: DataDirEnum,
 
 	/// Whether to fsync after all metadata transactions (disabled by default)
 	#[serde(default)]
@@ -94,6 +94,26 @@ pub struct Config {
 	pub admin: AdminConfig,
 }
 
+/// Value for data_dir: either a single directory or a list of dirs with attributes
+#[derive(Deserialize, Debug, Clone)]
+#[serde(untagged)]
+pub enum DataDirEnum {
+	Single(PathBuf),
+	Multiple(Vec<DataDir>),
+}
+
+#[derive(Deserialize, Debug, Clone)]
+pub struct DataDir {
+	/// Path to the data directory
+	pub path: PathBuf,
+	/// Capacity of the drive (required if read_only is false)
+	#[serde(default)]
+	pub capacity: Option<String>,
+	/// Whether this is a legacy read-only path (capacity should be None)
+	#[serde(default)]
+	pub read_only: bool,
+}
+
 /// Configuration for S3 api
 #[derive(Deserialize, Debug, Clone)]
 pub struct S3ApiConfig {