From 8fad728e9b277899ee7895c834302c52151a1ef4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Tomasz=20Drwi=C4=99ga?= <tomusdrw@users.noreply.github.com>
Date: Sun, 19 Jun 2016 12:33:50 +0200
Subject: [PATCH] Fixing locks order (#1328)

---
 ethcore/src/miner/miner.rs | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/ethcore/src/miner/miner.rs b/ethcore/src/miner/miner.rs
index ec232d238..ef59de1ec 100644
--- a/ethcore/src/miner/miner.rs
+++ b/ethcore/src/miner/miner.rs
@@ -31,13 +31,14 @@ use miner::{MinerService, MinerStatus, TransactionQueue, AccountDetails, Transac
 
 /// Keeps track of transactions using priority queue and holds currently mined block.
 pub struct Miner {
+	// NOTE [ToDr]  When locking always lock in this order!
 	transaction_queue: Mutex<TransactionQueue>,
+	sealing_work: Mutex<UsingQueue<ClosedBlock>>,
 
 	// for sealing...
 	force_sealing: bool,
 	sealing_enabled: AtomicBool,
 	sealing_block_last_request: Mutex<u64>,
-	sealing_work: Mutex<UsingQueue<ClosedBlock>>,
 	gas_floor_target: RwLock<U256>,
 	author: RwLock<Address>,
 	extra_data: RwLock<Bytes>,
@@ -424,20 +425,20 @@ impl MinerService for Miner {
 	}
 
 	fn pending_transactions_hashes(&self) -> Vec<H256> {
+		let queue = self.transaction_queue.lock().unwrap();
 		match (self.sealing_enabled.load(atomic::Ordering::Relaxed), self.sealing_work.lock().unwrap().peek_last_ref()) {
 			(true, Some(pending)) => pending.transactions().iter().map(|t| t.hash()).collect(),
 			_ => {
-				let queue = self.transaction_queue.lock().unwrap();
 				queue.pending_hashes()
 			}
 		}
 	}
 
 	fn transaction(&self, hash: &H256) -> Option<SignedTransaction> {
+		let queue = self.transaction_queue.lock().unwrap();
 		match (self.sealing_enabled.load(atomic::Ordering::Relaxed), self.sealing_work.lock().unwrap().peek_last_ref()) {
 			(true, Some(pending)) => pending.transactions().iter().find(|t| &t.hash() == hash).cloned(),
 			_ => {
-				let queue = self.transaction_queue.lock().unwrap();
 				queue.find(hash)
 			}
 		}
@@ -449,11 +450,11 @@ impl MinerService for Miner {
 	}
 
 	fn pending_transactions(&self) -> Vec<SignedTransaction> {
+		let queue = self.transaction_queue.lock().unwrap();
 		// TODO: should only use the sealing_work when it's current (it could be an old block)
 		match (self.sealing_enabled.load(atomic::Ordering::Relaxed), self.sealing_work.lock().unwrap().peek_last_ref()) {
 			(true, Some(pending)) => pending.transactions().clone(),
 			_ => {
-				let queue = self.transaction_queue.lock().unwrap();
 				queue.top_transactions()
 			}
 		}