refactor(tvix/castore/blobservice/memory): use parking_lot RwLock

This one doesn't require us to deal with poisoning, is upgradeable and
the right thing to use when locking access to data, not IO resources.

Change-Id: I78634953a73404500d28f51f1d93a87e215c8149
Reviewed-on: https://cl.tvl.fyi/c/depot/+/11612
Autosubmit: flokli <flokli@flokli.de>
Tested-by: BuildkiteCI
Reviewed-by: Connor Brewster <cbrewster@hey.com>

tvix/Cargo.lock

@@ -2305,7 +2305,7 @@ dependencies = [
  "hyper 0.14.28",
  "itertools 0.12.0",
  "md-5",
- "parking_lot 0.12.1",
+ "parking_lot 0.12.2",
  "percent-encoding",
  "quick-xml",
  "rand",
@@ -2460,9 +2460,9 @@ dependencies = [
 
 [[package]]
 name = "parking_lot"
-version = "0.12.1"
+version = "0.12.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3742b2c103b9f06bc9fff0a37ff4912935851bee6d36f3c02bcc755bcfec228f"
+checksum = "7e4af0ca4f6caed20e900d564c242b8e5d4903fdacf31d3daf527b66fe6f42fb"
 dependencies = [
  "lock_api",
  "parking_lot_core 0.9.9",
@@ -4298,7 +4298,7 @@ dependencies = [
  "lazy_static",
  "libc",
  "object_store",
- "parking_lot 0.12.1",
+ "parking_lot 0.12.2",
  "petgraph",
  "pin-project-lite",
  "prost 0.12.3",
@@ -4472,6 +4472,7 @@ dependencies = [
  "opentelemetry",
  "opentelemetry-otlp",
  "opentelemetry_sdk",
+ "parking_lot 0.12.2",
  "pin-project-lite",
  "prost 0.12.3",
  "prost-build",

tvix/Cargo.nix

@@ -7112,7 +7112,7 @@ rec {
           }
           {
             name = "parking_lot";
-            packageId = "parking_lot 0.12.1";
+            packageId = "parking_lot 0.12.2";
           }
           {
             name = "percent-encoding";
@@ -7683,11 +7683,11 @@ rec {
         };
         resolvedDefaultFeatures = [ "default" ];
       };
-      "parking_lot 0.12.1" = rec {
+      "parking_lot 0.12.2" = rec {
         crateName = "parking_lot";
-        version = "0.12.1";
-        edition = "2018";
-        sha256 = "13r2xk7mnxfc5g0g6dkdxqdqad99j7s7z8zhzz4npw5r0g0v4hip";
+        version = "0.12.2";
+        edition = "2021";
+        sha256 = "1ys2dzz6cysjmwyivwxczl1ljpcf5cj4qmhdj07d5bkc9z5g0jky";
         authors = [
           "Amanieu d'Antras <amanieu@gmail.com>"
         ];
@@ -13697,7 +13697,7 @@ rec {
           }
           {
             name = "parking_lot";
-            packageId = "parking_lot 0.12.1";
+            packageId = "parking_lot 0.12.2";
           }
           {
             name = "petgraph";
@@ -14430,6 +14430,10 @@ rec {
             optional = true;
             features = [ "rt-tokio" ];
           }
+          {
+            name = "parking_lot";
+            packageId = "parking_lot 0.12.2";
+          }
           {
             name = "pin-project-lite";
             packageId = "pin-project-lite";

tvix/castore/src/blobservice/memory.rs

@@ -1,9 +1,7 @@
+use parking_lot::RwLock;
 use std::io::{self, Cursor, Write};
 use std::task::Poll;
-use std::{
-    collections::HashMap,
-    sync::{Arc, RwLock},
-};
+use std::{collections::HashMap, sync::Arc};
 use tonic::async_trait;
 use tracing::instrument;
 
@@ -19,13 +17,13 @@ pub struct MemoryBlobService {
 impl BlobService for MemoryBlobService {
     #[instrument(skip_all, ret, err, fields(blob.digest=%digest))]
     async fn has(&self, digest: &B3Digest) -> io::Result<bool> {
-        let db = self.db.read().unwrap();
+        let db = self.db.read();
         Ok(db.contains_key(digest))
     }
 
     #[instrument(skip_all, err, fields(blob.digest=%digest))]
     async fn open_read(&self, digest: &B3Digest) -> io::Result<Option<Box<dyn BlobReader>>> {
-        let db = self.db.read().unwrap();
+        let db = self.db.read();
 
         match db.get(digest).map(|x| Cursor::new(x.clone())) {
             Some(result) => Ok(Some(Box::new(result))),
@@ -109,24 +107,16 @@ impl BlobWriter for MemoryBlobWriter {
         } else {
             let (buf, hasher) = self.writers.take().unwrap();
 
-            // We know self.hasher is doing blake3 hashing, so this won't fail.
             let digest: B3Digest = hasher.finalize().as_bytes().into();
 
             // Only insert if the blob doesn't already exist.
-            let db = self.db.read().map_err(|e| {
-                io::Error::new(io::ErrorKind::BrokenPipe, format!("RwLock poisoned: {}", e))
-            })?;
+            let mut db = self.db.upgradable_read();
             if !db.contains_key(&digest) {
-                // drop the read lock, so we can open for writing.
-                drop(db);
-
                 // open the database for writing.
-                let mut db = self.db.write().map_err(|e| {
-                    io::Error::new(io::ErrorKind::BrokenPipe, format!("RwLock poisoned: {}", e))
-                })?;
-
-                // and put buf in there. This will move buf out.
-                db.insert(digest.clone(), buf);
+                db.with_upgraded(|db| {
+                    // and put buf in there. This will move buf out.
+                    db.insert(digest.clone(), buf);
+                });
             }
 
             self.digest = Some(digest.clone());

tvix/crate-hashes.json

@@ -1,4 +1,4 @@
 {
-  "bigtable_rs 0.2.9 (git+https://github.com/flokli/bigtable_rs?rev=0af404741dfc40eb9fa99cf4d4140a09c5c20df7#0af404741dfc40eb9fa99cf4d4140a09c5c20df7)": "1njjam1lx2xlnm7a41lga8601vmjgqz0fvc77x24gd04pc7avxll",
-  "wu-manber 0.1.0 (git+https://github.com/tvlfyi/wu-manber.git#0d5b22bea136659f7de60b102a7030e0daaa503d)": "1zhk83lbq99xzyjwphv2qrb8f8qgfqwa5bbbvyzm0z0bljsjv0pd"
+  "git+https://github.com/flokli/bigtable_rs?rev=0af404741dfc40eb9fa99cf4d4140a09c5c20df7#0.2.9": "1njjam1lx2xlnm7a41lga8601vmjgqz0fvc77x24gd04pc7avxll",
+  "git+https://github.com/tvlfyi/wu-manber.git#wu-manber@0.1.0": "1zhk83lbq99xzyjwphv2qrb8f8qgfqwa5bbbvyzm0z0bljsjv0pd"
 }

tvix/store/Cargo.toml

@@ -42,6 +42,7 @@ url = "2.4.0"
 walkdir = "2.4.0"
 reqwest = { version = "0.11.22", features = ["rustls-tls-native-roots", "stream"], default-features = false }
 lru = "0.12.3"
+parking_lot = "0.12.2"
 
 [dependencies.tonic-reflection]
 optional = true