From 687660b27f904422c689e09d2457293e5313d325 Mon Sep 17 00:00:00 2001
From: Alex Auvolat <alex@adnab.me>
Date: Tue, 13 Dec 2022 14:23:45 +0100
Subject: Implement `block list-errors` and `block info`

---
 src/block/manager.rs | 34 ++++++++++++++++++++++++++++++++++
 src/block/rc.rs      |  7 +++++++
 src/block/resync.rs  | 12 +++++++-----
 3 files changed, 48 insertions(+), 5 deletions(-)

(limited to 'src/block')

diff --git a/src/block/manager.rs b/src/block/manager.rs
index 7f439b96..26e15bf5 100644
--- a/src/block/manager.rs
+++ b/src/block/manager.rs
@@ -90,6 +90,15 @@ pub struct BlockManager {
 	tx_scrub_command: 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.
@@ -314,6 +323,31 @@ impl BlockManager {
 		let _ = self.tx_scrub_command.send(cmd).await;
 	}
 
+	/// 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
diff --git a/src/block/rc.rs b/src/block/rc.rs
index ce6defad..8dae3960 100644
--- a/src/block/rc.rs
+++ b/src/block/rc.rs
@@ -169,4 +169,11 @@ impl RcEntry {
 	pub(crate) fn is_needed(&self) -> bool {
 		!self.is_deletable()
 	}
+
+	pub(crate) fn as_u64(&self) -> u64 {
+		match self {
+			RcEntry::Present { count } => *count,
+			_ => 0,
+		}
+	}
 }
diff --git a/src/block/resync.rs b/src/block/resync.rs
index 55d28c14..53b44774 100644
--- a/src/block/resync.rs
+++ b/src/block/resync.rs
@@ -540,9 +540,9 @@ impl Worker for ResyncWorker {
 /// and the time of the last try.
 /// Used to implement exponential backoff.
 #[derive(Clone, Copy, Debug)]
-struct ErrorCounter {
-	errors: u64,
-	last_try: u64,
+pub(crate) struct ErrorCounter {
+	pub(crate) errors: u64,
+	pub(crate) last_try: u64,
 }
 
 impl ErrorCounter {
@@ -553,12 +553,13 @@ impl ErrorCounter {
 		}
 	}
 
-	fn decode(data: &[u8]) -> Self {
+	pub(crate) fn decode(data: &[u8]) -> Self {
 		Self {
 			errors: u64::from_be_bytes(data[0..8].try_into().unwrap()),
 			last_try: u64::from_be_bytes(data[8..16].try_into().unwrap()),
 		}
 	}
+
 	fn encode(&self) -> Vec<u8> {
 		[
 			u64::to_be_bytes(self.errors),
@@ -578,7 +579,8 @@ impl ErrorCounter {
 		(RESYNC_RETRY_DELAY.as_millis() as u64)
 			<< std::cmp::min(self.errors - 1, RESYNC_RETRY_DELAY_MAX_BACKOFF_POWER)
 	}
-	fn next_try(&self) -> u64 {
+
+	pub(crate) fn next_try(&self) -> u64 {
 		self.last_try + self.delay_msec()
 	}
 }
-- 
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