From 022dfd15461791b3437dc8a5360f05c198bb4fd7 Mon Sep 17 00:00:00 2001
From: Nicholas Wehr <github@biochx.com>
Date: Thu, 21 Aug 2025 19:03:21 -0700
Subject: [PATCH] debug

---
 crates/net/hlfs/src/lib.rs | 93 +++++++++++++++++++++++++-------------
 1 file changed, 62 insertions(+), 31 deletions(-)

diff --git a/crates/net/hlfs/src/lib.rs b/crates/net/hlfs/src/lib.rs
index 9a8c88024..914f3f019 100644
--- a/crates/net/hlfs/src/lib.rs
+++ b/crates/net/hlfs/src/lib.rs
@@ -4,7 +4,6 @@ use bytes::{Buf, BufMut, Bytes, BytesMut};
 use parking_lot::Mutex;
 use reth_tracing::tracing::trace;
 use std::{
-    fs, io,
     net::SocketAddr,
     path::{Path, PathBuf},
     sync::Arc,
@@ -12,10 +11,11 @@ use std::{
 };
 use thiserror::Error;
 use tokio::{
-    io::{AsyncReadExt, AsyncWriteExt},
+    fs, io,
     net::{TcpListener, TcpStream},
     time::{sleep, timeout},
 };
+use tokio::fs::DirEntry;
 use tracing::{debug, info, warn};
 
 #[derive(Debug, Error)]
@@ -47,7 +47,7 @@ fn put_u32(b: &mut BytesMut, v: u32) {
 
 async fn ensure_parent_dirs(path: &str) -> std::io::Result<()> {
     if let Some(parent) = Path::new(path).parent() {
-        fs::create_dir_all(parent)
+        fs::create_dir_all(parent).await
     } else {
         Ok(())
     }
@@ -163,34 +163,61 @@ async fn fetch_once(addr: SocketAddr, number: u64) -> Result<Vec<u8>, HlfsError>
     }
 }
 
-fn find_max_number_file(root: &Path) -> Result<u64> {
-    fn parse_num(name: &str) -> Option<u64> {
-        name.strip_suffix(".rmp.lz4")?.parse::<u64>().ok()
+fn parse_block_file(name: &str) -> Option<u64> {
+    // expects "<number>.rmp.lz4"
+    let (stem, ext) = name.rsplit_once('.')?;
+    if ext != "lz4" {
+        return None;
     }
+    if !stem.ends_with(".rmp") {
+        return None;
+    }
+    let stem = stem.strip_suffix(".rmp")?;
+    stem.parse::<u64>().ok()
+}
 
-    fn walk(dir: &Path, best: &mut Option<u64>) -> io::Result<()> {
-        for entry in fs::read_dir(dir)? {
-            let entry = entry?;
-            let path = entry.path();
-            let ft = entry.file_type()?;
-            if ft.is_dir() {
-                walk(&path, best)?;
-            } else if ft.is_file() {
-                if let Some(name) = path.file_name().and_then(|s| s.to_str()) {
-                    if let Some(n) = parse_num(name) {
-                        if best.map_or(true, |(m, _)| n > m) {
-                            *best = Some((n, path.clone()));
+// Asynchronously find the largest block file under the 2-level shard layout:
+// {root}/{floor_to_million}/{floor_to_thousand}/{number}.rmp.lz4
+pub async fn find_max_block(root: &Path) -> io::Result<u64> {
+    let mut max_num: Option<u64> = None;
+
+    let mut top = fs::read_dir(root).await?;
+    while let Some(million_dir) = top.next_entry().await? {
+        if !million_dir.file_type().await?.is_dir() {
+            continue;
+        }
+        // Fast reject: top-level dir must parse to u64 (but we still scan if not—optional)
+        if million_dir.file_name().to_string_lossy().parse::<u64>().is_err() {
+            continue;
+        }
+
+        let mut mid = fs::read_dir(million_dir.path()).await?;
+        while let Some(thousand_dir) = mid.next_entry().await? {
+            if !thousand_dir.file_type().await?.is_dir() {
+                continue;
+            }
+            // Optional reject again for dir-name parse to u64
+            if thousand_dir.file_name().to_string_lossy().parse::<u64>().is_err() {
+                continue;
+            }
+
+            let mut leaf = fs::read_dir(thousand_dir.path()).await?;
+            while let Some(ent) = leaf.next_entry().await? {
+                if !ent.file_type().await?.is_file() {
+                    continue;
+                }
+                if let Some(name) = ent.file_name().to_str() {
+                    if let Some(n) = parse_block_file(name) {
+                        if max_num.map_or(true, |m| n > m) {
+                            max_num = Some(n);
                         }
                     }
                 }
             }
         }
-        Ok(())
     }
 
-    let mut best = None;
-    walk(root, &mut best)?;
-    Ok(best.expect("cannot find block files"))
+    max_num.ok_or_else(|| io::Error::new(io::ErrorKind::NotFound, "no block files found"))
 }
 
 /// Server: serves `{root}/{number}.rlp`.
@@ -204,24 +231,28 @@ pub struct Server {
 }
 
 impl Server {
-    pub fn new(bind: SocketAddr, root: impl Into<PathBuf>) -> Self {
-        let n = find_max_number_file(&root.into()).unwrap();
-        Self {
+    pub async fn new(bind: SocketAddr, root: impl Into<PathBuf>) -> Result<Self, HlfsError> {
+        let root = root.into();
+        fs::create_dir_all(&root).await?; // async, no unwrap/ok()
+        let max_block = find_max_block(&root).await?; // async discovery
+
+        Ok(Self {
             bind,
-            root: root.into(),
+            root,
             max_conns: 512,
-            inflight: Arc::new(Mutex::new(0)),
+            inflight: Arc::new(parking_lot::Mutex::new(0)),
             busy_retry_ms: 100,
-            max_block: n.unwrap(),
-        }
+            max_block,
+        })
     }
+
     pub fn with_limits(mut self, max_conns: usize, busy_retry_ms: u32) -> Self {
         self.max_conns = max_conns;
         self.busy_retry_ms = busy_retry_ms;
         self
     }
     pub async fn run(self) -> Result<(), HlfsError> {
-        fs::create_dir_all(&self.root).ok();
+        fs::create_dir_all(&self.root).await.ok();
         info!(%self.bind, root=%self.root.display(), max_conns=%self.max_conns, "hlfs: server listening");
         let lst = TcpListener::bind(self.bind).await?;
         loop {
@@ -253,7 +284,7 @@ async fn handle_conn(
 ) -> Result<(), HlfsError> {
     let mut op = [0u8; 1];
     sock.read_exact(&mut op).await?;
-    if op[0] != 0x01 || op[0] != 0x02 {
+    if op[0] != 0x01 && op[0] != 0x02 {
         warn!(%addr, "hlfs: bad op");
         return Err(HlfsError::Proto);
     }