WIP

Motivation
==========

It's the only user, and the name of `_for_write` is wrong as of

    commit 7a63685cde
    Author: Christian Schwarz <christian@neon.tech>
    Date:   Fri Aug 18 19:31:03 2023 +0200

        simplify page-caching of EphemeralFile (#4994)

Notes
=====

This also allows us to get rid of the WriteBufResult type.

Also rename `search_mapping_for_write` to `search_mapping_exact`.
It makes more sense that way because there is `_for_write`-locking
anymore.

.github/actions/allure-report-generate/action.yml

@@ -76,8 +76,8 @@ runs:
           rm -f ${ALLURE_ZIP}
         fi
       env:
-        ALLURE_VERSION: 2.23.1
-        ALLURE_ZIP_SHA256: 11141bfe727504b3fd80c0f9801eb317407fd0ac983ebb57e671f14bac4bcd86
+        ALLURE_VERSION: 2.24.0
+        ALLURE_ZIP_SHA256: 60b1d6ce65d9ef24b23cf9c2c19fd736a123487c38e54759f1ed1a7a77353c90
 
     # Potentially we could have several running build for the same key (for example, for the main branch), so we use improvised lock for this
     - name: Acquire lock

Cargo.lock

@@ -158,6 +158,17 @@ dependencies = [
  "syn 1.0.109",
 ]
 
+[[package]]
+name = "async-channel"
+version = "1.9.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "81953c529336010edd6d8e358f886d9581267795c61b19475b71314bffa46d35"
+dependencies = [
+ "concurrent-queue",
+ "event-listener",
+ "futures-core",
+]
+
 [[package]]
 name = "async-compression"
 version = "0.4.0"
@@ -798,6 +809,22 @@ dependencies = [
  "either",
 ]
 
+[[package]]
+name = "camino"
+version = "1.1.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c59e92b5a388f549b863a7bea62612c09f24c8393560709a54558a9abdfb3b9c"
+
+[[package]]
+name = "camino-tempfile"
+version = "1.0.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d2ab15a83d13f75dbd86f082bdefd160b628476ef58d3b900a0ef74e001bb097"
+dependencies = [
+ "camino",
+ "tempfile",
+]
+
 [[package]]
 name = "cast"
 version = "0.3.0"
@@ -1015,6 +1042,15 @@ dependencies = [
  "zstd",
 ]
 
+[[package]]
+name = "concurrent-queue"
+version = "2.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f057a694a54f12365049b0958a1685bb52d567f5593b355fbf685838e873d400"
+dependencies = [
+ "crossbeam-utils",
+]
+
 [[package]]
 name = "const_format"
 version = "0.2.30"
@@ -1053,6 +1089,7 @@ name = "control_plane"
 version = "0.1.0"
 dependencies = [
  "anyhow",
+ "camino",
  "clap",
  "comfy-table",
  "compute_api",
@@ -1435,6 +1472,12 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "event-listener"
+version = "2.5.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0206175f82b8d6bf6652ff7d71a1e27fd2e4efde587fd368662814d6ec1d9ce0"
+
 [[package]]
 name = "fail"
 version = "0.5.1"
@@ -2641,6 +2684,7 @@ version = "0.1.0"
 dependencies = [
  "anyhow",
  "bytes",
+ "camino",
  "clap",
  "git-version",
  "pageserver",
@@ -2656,11 +2700,14 @@ name = "pageserver"
 version = "0.1.0"
 dependencies = [
  "anyhow",
+ "async-channel",
  "async-compression",
  "async-stream",
  "async-trait",
  "byteorder",
  "bytes",
+ "camino",
+ "camino-tempfile",
  "chrono",
  "clap",
  "close_fds",
@@ -2712,7 +2759,6 @@ dependencies = [
  "strum_macros",
  "svg_fmt",
  "sync_wrapper",
- "tempfile",
  "tenant_size_model",
  "thiserror",
  "tokio",
@@ -3405,6 +3451,8 @@ dependencies = [
  "aws-sdk-s3",
  "aws-smithy-http",
  "aws-types",
+ "camino",
+ "camino-tempfile",
  "hyper",
  "metrics",
  "once_cell",
@@ -3413,7 +3461,6 @@ dependencies = [
  "scopeguard",
  "serde",
  "serde_json",
- "tempfile",
  "test-context",
  "tokio",
  "tokio-util",
@@ -3765,6 +3812,8 @@ dependencies = [
  "async-trait",
  "byteorder",
  "bytes",
+ "camino",
+ "camino-tempfile",
  "chrono",
  "clap",
  "const_format",
@@ -3793,7 +3842,6 @@ dependencies = [
  "serde_with",
  "signal-hook",
  "storage_broker",
- "tempfile",
  "thiserror",
  "tokio",
  "tokio-io-timeout",
@@ -5092,6 +5140,8 @@ dependencies = [
  "bincode",
  "byteorder",
  "bytes",
+ "camino",
+ "camino-tempfile",
  "chrono",
  "const_format",
  "criterion",
@@ -5117,7 +5167,6 @@ dependencies = [
  "signal-hook",
  "strum",
  "strum_macros",
- "tempfile",
  "thiserror",
  "tokio",
  "tokio-stream",
@@ -5191,6 +5240,7 @@ name = "wal_craft"
 version = "0.1.0"
 dependencies = [
  "anyhow",
+ "camino-tempfile",
  "clap",
  "env_logger",
  "log",
@@ -5198,7 +5248,6 @@ dependencies = [
  "postgres",
  "postgres_ffi",
  "regex",
- "tempfile",
  "utils",
  "workspace_hack",
 ]

Cargo.toml

@@ -35,6 +35,7 @@ license = "Apache-2.0"
 ## All dependency versions, used in the project
 [workspace.dependencies]
 anyhow = { version = "1.0", features = ["backtrace"] }
+async-channel = "1.9.0"
 async-compression = { version = "0.4.0", features = ["tokio", "gzip"] }
 flate2 = "1.0.26"
 async-stream = "0.3"
@@ -51,6 +52,7 @@ bindgen = "0.65"
 bstr = "1.0"
 byteorder = "1.4"
 bytes = "1.0"
+camino = "1.1.6"
 cfg-if = "1.0.0"
 chrono = { version = "0.4", default-features = false, features = ["clock"] }
 clap = { version = "4.0", features = ["derive"] }
@@ -187,7 +189,7 @@ workspace_hack = { version = "0.1", path = "./workspace_hack/" }
 criterion = "0.5.1"
 rcgen = "0.11"
 rstest = "0.18"
-tempfile = "3.4"
+camino-tempfile = "1.0.2"
 tonic-build = "0.9"
 
 [patch.crates-io]

Dockerfile.compute-node

@@ -651,7 +651,7 @@ FROM rust-extensions-build AS pg-jsonschema-pg-build
 ARG PG_VERSION
 
 RUN wget https://github.com/supabase/pg_jsonschema/archive/refs/tags/v0.2.0.tar.gz -O pg_jsonschema.tar.gz && \
-    echo "b1bd95009c8809bd6cda9a37777f8b7df425ff1a34976c1e7a4b31cf838ace66 pg_jsonschema.tar.gz" | sha256sum --check && \
+    echo "9118fc508a6e231e7a39acaa6f066fcd79af17a5db757b47d2eefbe14f7794f0 pg_jsonschema.tar.gz" | sha256sum --check && \
     mkdir pg_jsonschema-src && cd pg_jsonschema-src && tar xvzf ../pg_jsonschema.tar.gz --strip-components=1 -C . && \
     sed -i 's/pgrx = "0.10.2"/pgrx = { version = "0.10.2", features = [ "unsafe-postgres" ] }/g' Cargo.toml && \
     cargo pgrx install --release && \
@@ -668,7 +668,7 @@ FROM rust-extensions-build AS pg-graphql-pg-build
 ARG PG_VERSION
 
 RUN wget https://github.com/supabase/pg_graphql/archive/refs/tags/v1.4.0.tar.gz -O pg_graphql.tar.gz && \
-    echo "ea85d45f8af1d2382e2af847f88102f930782c00e6c612308e6f08f27309d5f7 pg_graphql.tar.gz" | sha256sum --check && \
+    echo "bd8dc7230282b3efa9ae5baf053a54151ed0e66881c7c53750e2d0c765776edc pg_graphql.tar.gz" | sha256sum --check && \
     mkdir pg_graphql-src && cd pg_graphql-src && tar xvzf ../pg_graphql.tar.gz --strip-components=1 -C . && \
     sed -i 's/pgrx = "=0.10.2"/pgrx = { version = "0.10.2", features = [ "unsafe-postgres" ] }/g' Cargo.toml && \
     cargo pgrx install --release && \

compute_tools/src/compute.rs

@@ -1039,7 +1039,7 @@ LIMIT 100",
         let remote_extensions = spec
             .remote_extensions
             .as_ref()
-            .ok_or(anyhow::anyhow!("Remote extensions are not configured",))?;
+            .ok_or(anyhow::anyhow!("Remote extensions are not configured"))?;
 
         info!("parse shared_preload_libraries from spec.cluster.settings");
         let mut libs_vec = Vec::new();

compute_tools/src/monitor.rs

@@ -1,5 +1,5 @@
 use std::sync::Arc;
-use std::{thread, time};
+use std::{thread, time::Duration};
 
 use chrono::{DateTime, Utc};
 use postgres::{Client, NoTls};
@@ -7,7 +7,7 @@ use tracing::{debug, info};
 
 use crate::compute::ComputeNode;
 
-const MONITOR_CHECK_INTERVAL: u64 = 500; // milliseconds
+const MONITOR_CHECK_INTERVAL: Duration = Duration::from_millis(500);
 
 // Spin in a loop and figure out the last activity time in the Postgres.
 // Then update it in the shared state. This function never errors out.
@@ -17,13 +17,12 @@ fn watch_compute_activity(compute: &ComputeNode) {
     let connstr = compute.connstr.as_str();
     // Define `client` outside of the loop to reuse existing connection if it's active.
     let mut client = Client::connect(connstr, NoTls);
-    let timeout = time::Duration::from_millis(MONITOR_CHECK_INTERVAL);
 
     info!("watching Postgres activity at {}", connstr);
 
     loop {
         // Should be outside of the write lock to allow others to read while we sleep.
-        thread::sleep(timeout);
+        thread::sleep(MONITOR_CHECK_INTERVAL);
 
         match &mut client {
             Ok(cli) => {

control_plane/Cargo.toml

@@ -6,6 +6,7 @@ license.workspace = true
 
 [dependencies]
 anyhow.workspace = true
+camino.workspace = true
 clap.workspace = true
 comfy-table.workspace = true
 git-version.workspace = true

control_plane/src/attachment_service.rs

@@ -1,5 +1,6 @@
 use crate::{background_process, local_env::LocalEnv};
 use anyhow::anyhow;
+use camino::Utf8PathBuf;
 use serde::{Deserialize, Serialize};
 use serde_with::{serde_as, DisplayFromStr};
 use std::{path::PathBuf, process::Child};
@@ -47,8 +48,9 @@ impl AttachmentService {
         }
     }
 
-    fn pid_file(&self) -> PathBuf {
-        self.env.base_data_dir.join("attachment_service.pid")
+    fn pid_file(&self) -> Utf8PathBuf {
+        Utf8PathBuf::from_path_buf(self.env.base_data_dir.join("attachment_service.pid"))
+            .expect("non-Unicode path")
     }
 
     pub fn start(&self) -> anyhow::Result<Child> {

control_plane/src/background_process.rs

@@ -16,12 +16,13 @@ use std::ffi::OsStr;
 use std::io::Write;
 use std::os::unix::prelude::AsRawFd;
 use std::os::unix::process::CommandExt;
-use std::path::{Path, PathBuf};
+use std::path::Path;
 use std::process::{Child, Command};
 use std::time::Duration;
 use std::{fs, io, thread};
 
 use anyhow::Context;
+use camino::{Utf8Path, Utf8PathBuf};
 use nix::errno::Errno;
 use nix::fcntl::{FcntlArg, FdFlag};
 use nix::sys::signal::{kill, Signal};
@@ -45,9 +46,9 @@ const NOTICE_AFTER_RETRIES: u64 = 50;
 /// it itself.
 pub enum InitialPidFile<'t> {
     /// Create a pidfile, to allow future CLI invocations to manipulate the process.
-    Create(&'t Path),
+    Create(&'t Utf8Path),
     /// The process will create the pidfile itself, need to wait for that event.
-    Expect(&'t Path),
+    Expect(&'t Utf8Path),
 }
 
 /// Start a background child process using the parameters given.
@@ -137,7 +138,11 @@ where
 }
 
 /// Stops the process, using the pid file given. Returns Ok also if the process is already not running.
-pub fn stop_process(immediate: bool, process_name: &str, pid_file: &Path) -> anyhow::Result<()> {
+pub fn stop_process(
+    immediate: bool,
+    process_name: &str,
+    pid_file: &Utf8Path,
+) -> anyhow::Result<()> {
     let pid = match pid_file::read(pid_file)
         .with_context(|| format!("read pid_file {pid_file:?}"))?
     {
@@ -252,9 +257,9 @@ fn fill_aws_secrets_vars(mut cmd: &mut Command) -> &mut Command {
 ///    will remain held until the cmd exits.
 fn pre_exec_create_pidfile<P>(cmd: &mut Command, path: P) -> &mut Command
 where
-    P: Into<PathBuf>,
+    P: Into<Utf8PathBuf>,
 {
-    let path: PathBuf = path.into();
+    let path: Utf8PathBuf = path.into();
     // SAFETY
     // pre_exec is marked unsafe because it runs between fork and exec.
     // Why is that dangerous in various ways?
@@ -311,7 +316,7 @@ where
 
 fn process_started<F>(
     pid: Pid,
-    pid_file_to_check: Option<&Path>,
+    pid_file_to_check: Option<&Utf8Path>,
     status_check: &F,
 ) -> anyhow::Result<bool>
 where

control_plane/src/broker.rs

@@ -7,7 +7,7 @@
 //! ```
 use anyhow::Context;
 
-use std::path::PathBuf;
+use camino::Utf8PathBuf;
 
 use crate::{background_process, local_env};
 
@@ -30,7 +30,7 @@ pub fn start_broker_process(env: &local_env::LocalEnv) -> anyhow::Result<()> {
         || {
             let url = broker.client_url();
             let status_url = url.join("status").with_context(|| {
-                format!("Failed to append /status path to broker endpoint {url}",)
+                format!("Failed to append /status path to broker endpoint {url}")
             })?;
             let request = client
                 .get(status_url)
@@ -50,6 +50,7 @@ pub fn stop_broker_process(env: &local_env::LocalEnv) -> anyhow::Result<()> {
     background_process::stop_process(true, "storage_broker", &storage_broker_pid_file_path(env))
 }
 
-fn storage_broker_pid_file_path(env: &local_env::LocalEnv) -> PathBuf {
-    env.base_data_dir.join("storage_broker.pid")
+fn storage_broker_pid_file_path(env: &local_env::LocalEnv) -> Utf8PathBuf {
+    Utf8PathBuf::from_path_buf(env.base_data_dir.join("storage_broker.pid"))
+        .expect("non-Unicode path")
 }

control_plane/src/pageserver.rs

@@ -14,6 +14,7 @@ use std::process::{Child, Command};
 use std::{io, result};
 
 use anyhow::{bail, Context};
+use camino::Utf8PathBuf;
 use pageserver_api::models::{self, TenantInfo, TimelineInfo};
 use postgres_backend::AuthType;
 use postgres_connection::{parse_host_port, PgConnectionConfig};
@@ -144,7 +145,7 @@ impl PageServerNode {
     pub fn initialize(&self, config_overrides: &[&str]) -> anyhow::Result<()> {
         // First, run `pageserver --init` and wait for it to write a config into FS and exit.
         self.pageserver_init(config_overrides)
-            .with_context(|| format!("Failed to run init for pageserver node {}", self.conf.id,))
+            .with_context(|| format!("Failed to run init for pageserver node {}", self.conf.id))
     }
 
     pub fn repo_path(&self) -> PathBuf {
@@ -154,8 +155,9 @@ impl PageServerNode {
     /// The pid file is created by the pageserver process, with its pid stored inside.
     /// Other pageservers cannot lock the same file and overwrite it for as long as the current
     /// pageserver runs. (Unless someone removes the file manually; never do that!)
-    fn pid_file(&self) -> PathBuf {
-        self.repo_path().join("pageserver.pid")
+    fn pid_file(&self) -> Utf8PathBuf {
+        Utf8PathBuf::from_path_buf(self.repo_path().join("pageserver.pid"))
+            .expect("non-Unicode path")
     }
 
     pub fn start(&self, config_overrides: &[&str]) -> anyhow::Result<Child> {

control_plane/src/safekeeper.rs

@@ -11,6 +11,7 @@ use std::process::Child;
 use std::{io, result};
 
 use anyhow::Context;
+use camino::Utf8PathBuf;
 use postgres_connection::PgConnectionConfig;
 use reqwest::blocking::{Client, RequestBuilder, Response};
 use reqwest::{IntoUrl, Method};
@@ -97,8 +98,9 @@ impl SafekeeperNode {
         SafekeeperNode::datadir_path_by_id(&self.env, self.id)
     }
 
-    pub fn pid_file(&self) -> PathBuf {
-        self.datadir_path().join("safekeeper.pid")
+    pub fn pid_file(&self) -> Utf8PathBuf {
+        Utf8PathBuf::from_path_buf(self.datadir_path().join("safekeeper.pid"))
+            .expect("non-Unicode path")
     }
 
     pub fn start(&self, extra_opts: Vec<String>) -> anyhow::Result<Child> {

libs/pageserver_api/src/models.rs

@@ -10,6 +10,7 @@ use serde_with::{serde_as, DisplayFromStr};
 use strum_macros;
 use utils::{
     completion,
+    generation::Generation,
     history_buffer::HistoryBufferWithDropCounter,
     id::{NodeId, TenantId, TimelineId},
     lsn::Lsn,
@@ -218,6 +219,8 @@ impl std::ops::Deref for TenantCreateRequest {
     }
 }
 
+/// An alternative representation of `pageserver::tenant::TenantConf` with
+/// simpler types.
 #[derive(Serialize, Deserialize, Debug, Default)]
 pub struct TenantConfig {
     pub checkpoint_distance: Option<u64>,
@@ -243,6 +246,39 @@ pub struct TenantConfig {
     pub gc_feedback: Option<bool>,
 }
 
+/// A flattened analog of a `pagesever::tenant::LocationMode`, which
+/// lists out all possible states (and the virtual "Detached" state)
+/// in a flat form rather than using rust-style enums.
+#[derive(Serialize, Deserialize, Debug)]
+pub enum LocationConfigMode {
+    AttachedSingle,
+    AttachedMulti,
+    AttachedStale,
+    Secondary,
+    Detached,
+}
+
+#[derive(Serialize, Deserialize, Debug)]
+pub struct LocationConfigSecondary {
+    pub warm: bool,
+}
+
+/// An alternative representation of `pageserver::tenant::LocationConf`,
+/// for use in external-facing APIs.
+#[derive(Serialize, Deserialize, Debug)]
+pub struct LocationConfig {
+    pub mode: LocationConfigMode,
+    /// If attaching, in what generation?
+    #[serde(default)]
+    pub generation: Option<Generation>,
+    #[serde(default)]
+    pub secondary_conf: Option<LocationConfigSecondary>,
+
+    // If requesting mode `Secondary`, configuration for that.
+    // Custom storage configuration for the tenant, if any
+    pub tenant_conf: TenantConfig,
+}
+
 #[serde_as]
 #[derive(Serialize, Deserialize)]
 #[serde(transparent)]
@@ -253,6 +289,16 @@ pub struct StatusResponse {
     pub id: NodeId,
 }
 
+#[serde_as]
+#[derive(Serialize, Deserialize, Debug)]
+#[serde(deny_unknown_fields)]
+pub struct TenantLocationConfigRequest {
+    #[serde_as(as = "DisplayFromStr")]
+    pub tenant_id: TenantId,
+    #[serde(flatten)]
+    pub config: LocationConfig, // as we have a flattened field, we should reject all unknown fields in it
+}
+
 #[serde_as]
 #[derive(Serialize, Deserialize, Debug)]
 #[serde(deny_unknown_fields)]

libs/postgres_ffi/wal_craft/Cargo.toml

@@ -12,7 +12,7 @@ log.workspace = true
 once_cell.workspace = true
 postgres.workspace = true
 postgres_ffi.workspace = true
-tempfile.workspace = true
+camino-tempfile.workspace = true
 
 workspace_hack.workspace = true
 

libs/postgres_ffi/wal_craft/src/lib.rs

@@ -1,4 +1,5 @@
 use anyhow::{bail, ensure};
+use camino_tempfile::{tempdir, Utf8TempDir};
 use log::*;
 use postgres::types::PgLsn;
 use postgres::Client;
@@ -8,7 +9,6 @@ use std::cmp::Ordering;
 use std::path::{Path, PathBuf};
 use std::process::Command;
 use std::time::{Duration, Instant};
-use tempfile::{tempdir, TempDir};
 
 macro_rules! xlog_utils_test {
     ($version:ident) => {
@@ -33,7 +33,7 @@ pub struct Conf {
 
 pub struct PostgresServer {
     process: std::process::Child,
-    _unix_socket_dir: TempDir,
+    _unix_socket_dir: Utf8TempDir,
     client_config: postgres::Config,
 }
 

libs/remote_storage/Cargo.toml

@@ -13,6 +13,7 @@ aws-types.workspace = true
 aws-config.workspace = true
 aws-sdk-s3.workspace = true
 aws-credential-types.workspace = true
+camino.workspace = true
 hyper = { workspace = true, features = ["stream"] }
 serde.workspace = true
 serde_json.workspace = true
@@ -27,6 +28,6 @@ pin-project-lite.workspace = true
 workspace_hack.workspace = true
 
 [dev-dependencies]
-tempfile.workspace = true
+camino-tempfile.workspace = true
 test-context.workspace = true
 rand.workspace = true

libs/remote_storage/src/lib.rs

@@ -13,12 +13,12 @@ use std::{
     collections::HashMap,
     fmt::Debug,
     num::{NonZeroU32, NonZeroUsize},
-    path::{Path, PathBuf},
     pin::Pin,
     sync::Arc,
 };
 
 use anyhow::{bail, Context};
+use camino::{Utf8Path, Utf8PathBuf};
 
 use serde::{Deserialize, Serialize};
 use tokio::io;
@@ -52,7 +52,7 @@ const REMOTE_STORAGE_PREFIX_SEPARATOR: char = '/';
 /// The prefix is an implementation detail, that allows representing local paths
 /// as the remote ones, stripping the local storage prefix away.
 #[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
-pub struct RemotePath(PathBuf);
+pub struct RemotePath(Utf8PathBuf);
 
 impl Serialize for RemotePath {
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
@@ -69,18 +69,18 @@ impl<'de> Deserialize<'de> for RemotePath {
         D: serde::Deserializer<'de>,
     {
         let str = String::deserialize(deserializer)?;
-        Ok(Self(PathBuf::from(&str)))
+        Ok(Self(Utf8PathBuf::from(&str)))
     }
 }
 
 impl std::fmt::Display for RemotePath {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        write!(f, "{}", self.0.display())
+        std::fmt::Display::fmt(&self.0, f)
     }
 }
 
 impl RemotePath {
-    pub fn new(relative_path: &Path) -> anyhow::Result<Self> {
+    pub fn new(relative_path: &Utf8Path) -> anyhow::Result<Self> {
         anyhow::ensure!(
             relative_path.is_relative(),
             "Path {relative_path:?} is not relative"
@@ -89,30 +89,30 @@ impl RemotePath {
     }
 
     pub fn from_string(relative_path: &str) -> anyhow::Result<Self> {
-        Self::new(Path::new(relative_path))
+        Self::new(Utf8Path::new(relative_path))
     }
 
-    pub fn with_base(&self, base_path: &Path) -> PathBuf {
+    pub fn with_base(&self, base_path: &Utf8Path) -> Utf8PathBuf {
         base_path.join(&self.0)
     }
 
     pub fn object_name(&self) -> Option<&str> {
-        self.0.file_name().and_then(|os_str| os_str.to_str())
+        self.0.file_name()
     }
 
-    pub fn join(&self, segment: &Path) -> Self {
+    pub fn join(&self, segment: &Utf8Path) -> Self {
         Self(self.0.join(segment))
     }
 
-    pub fn get_path(&self) -> &PathBuf {
+    pub fn get_path(&self) -> &Utf8PathBuf {
         &self.0
     }
 
     pub fn extension(&self) -> Option<&str> {
-        self.0.extension()?.to_str()
+        self.0.extension()
     }
 
-    pub fn strip_prefix(&self, p: &RemotePath) -> Result<&Path, std::path::StripPrefixError> {
+    pub fn strip_prefix(&self, p: &RemotePath) -> Result<&Utf8Path, std::path::StripPrefixError> {
         self.0.strip_prefix(&p.0)
     }
 }
@@ -311,7 +311,7 @@ impl GenericRemoteStorage {
     pub fn from_config(storage_config: &RemoteStorageConfig) -> anyhow::Result<Self> {
         Ok(match &storage_config.storage {
             RemoteStorageKind::LocalFs(root) => {
-                info!("Using fs root '{}' as a remote storage", root.display());
+                info!("Using fs root '{root}' as a remote storage");
                 Self::LocalFs(LocalFs::new(root.clone())?)
             }
             RemoteStorageKind::AwsS3(s3_config) => {
@@ -379,7 +379,7 @@ pub struct RemoteStorageConfig {
 pub enum RemoteStorageKind {
     /// Storage based on local file system.
     /// Specify a root folder to place all stored files into.
-    LocalFs(PathBuf),
+    LocalFs(Utf8PathBuf),
     /// AWS S3 based storage, storing all files in the S3 bucket
     /// specified by the config
     AwsS3(S3Config),
@@ -474,7 +474,7 @@ impl RemoteStorageConfig {
                 concurrency_limit,
                 max_keys_per_list_response,
             }),
-            (Some(local_path), None, None) => RemoteStorageKind::LocalFs(PathBuf::from(
+            (Some(local_path), None, None) => RemoteStorageKind::LocalFs(Utf8PathBuf::from(
                 parse_toml_string("local_path", local_path)?,
             )),
             (Some(_), Some(_), _) => bail!("local_path and bucket_name are mutually exclusive"),
@@ -519,23 +519,23 @@ mod tests {
 
     #[test]
     fn test_object_name() {
-        let k = RemotePath::new(Path::new("a/b/c")).unwrap();
+        let k = RemotePath::new(Utf8Path::new("a/b/c")).unwrap();
         assert_eq!(k.object_name(), Some("c"));
 
-        let k = RemotePath::new(Path::new("a/b/c/")).unwrap();
+        let k = RemotePath::new(Utf8Path::new("a/b/c/")).unwrap();
         assert_eq!(k.object_name(), Some("c"));
 
-        let k = RemotePath::new(Path::new("a/")).unwrap();
+        let k = RemotePath::new(Utf8Path::new("a/")).unwrap();
         assert_eq!(k.object_name(), Some("a"));
 
         // XXX is it impossible to have an empty key?
-        let k = RemotePath::new(Path::new("")).unwrap();
+        let k = RemotePath::new(Utf8Path::new("")).unwrap();
         assert_eq!(k.object_name(), None);
     }
 
     #[test]
     fn rempte_path_cannot_be_created_from_absolute_ones() {
-        let err = RemotePath::new(Path::new("/")).expect_err("Should fail on absolute paths");
+        let err = RemotePath::new(Utf8Path::new("/")).expect_err("Should fail on absolute paths");
         assert_eq!(err.to_string(), "Path \"/\" is not relative");
     }
 }

libs/remote_storage/src/local_fs.rs

@@ -4,15 +4,10 @@
 //! This storage used in tests, but can also be used in cases when a certain persistent
 //! volume is mounted to the local FS.
 
-use std::{
-    borrow::Cow,
-    future::Future,
-    io::ErrorKind,
-    path::{Path, PathBuf},
-    pin::Pin,
-};
+use std::{borrow::Cow, future::Future, io::ErrorKind, pin::Pin};
 
 use anyhow::{bail, ensure, Context};
+use camino::{Utf8Path, Utf8PathBuf};
 use tokio::{
     fs,
     io::{self, AsyncReadExt, AsyncSeekExt, AsyncWriteExt},
@@ -28,20 +23,20 @@ const LOCAL_FS_TEMP_FILE_SUFFIX: &str = "___temp";
 
 #[derive(Debug, Clone)]
 pub struct LocalFs {
-    storage_root: PathBuf,
+    storage_root: Utf8PathBuf,
 }
 
 impl LocalFs {
     /// Attempts to create local FS storage, along with its root directory.
     /// Storage root will be created (if does not exist) and transformed into an absolute path (if passed as relative).
-    pub fn new(mut storage_root: PathBuf) -> anyhow::Result<Self> {
+    pub fn new(mut storage_root: Utf8PathBuf) -> anyhow::Result<Self> {
         if !storage_root.exists() {
             std::fs::create_dir_all(&storage_root).with_context(|| {
                 format!("Failed to create all directories in the given root path {storage_root:?}")
             })?;
         }
         if !storage_root.is_absolute() {
-            storage_root = storage_root.canonicalize().with_context(|| {
+            storage_root = storage_root.canonicalize_utf8().with_context(|| {
                 format!("Failed to represent path {storage_root:?} as an absolute path")
             })?;
         }
@@ -50,7 +45,7 @@ impl LocalFs {
     }
 
     // mirrors S3Bucket::s3_object_to_relative_path
-    fn local_file_to_relative_path(&self, key: PathBuf) -> RemotePath {
+    fn local_file_to_relative_path(&self, key: Utf8PathBuf) -> RemotePath {
         let relative_path = key
             .strip_prefix(&self.storage_root)
             .expect("relative path must contain storage_root as prefix");
@@ -59,22 +54,18 @@ impl LocalFs {
 
     async fn read_storage_metadata(
         &self,
-        file_path: &Path,
+        file_path: &Utf8Path,
     ) -> anyhow::Result<Option<StorageMetadata>> {
         let metadata_path = storage_metadata_path(file_path);
         if metadata_path.exists() && metadata_path.is_file() {
             let metadata_string = fs::read_to_string(&metadata_path).await.with_context(|| {
-                format!(
-                    "Failed to read metadata from the local storage at '{}'",
-                    metadata_path.display()
-                )
+                format!("Failed to read metadata from the local storage at '{metadata_path}'")
             })?;
 
             serde_json::from_str(&metadata_string)
                 .with_context(|| {
                     format!(
-                        "Failed to deserialize metadata from the local storage at '{}'",
-                        metadata_path.display()
+                        "Failed to deserialize metadata from the local storage at '{metadata_path}'",
                     )
                 })
                 .map(|metadata| Some(StorageMetadata(metadata)))
@@ -171,25 +162,21 @@ impl RemoteStorage for LocalFs {
             }
         }
 
-        // Note that PathBuf starts_with only considers full path segments, but
+        // Note that Utf8PathBuf starts_with only considers full path segments, but
         // object prefixes are arbitrary strings, so we need the strings for doing
         // starts_with later.
-        let prefix = full_path.to_string_lossy();
+        let prefix = full_path.as_str();
 
         let mut files = vec![];
-        let mut directory_queue = vec![initial_dir.clone()];
+        let mut directory_queue = vec![initial_dir];
         while let Some(cur_folder) = directory_queue.pop() {
-            let mut entries = fs::read_dir(cur_folder.clone()).await?;
-            while let Some(entry) = entries.next_entry().await? {
-                let file_name: PathBuf = entry.file_name().into();
-                let full_file_name = cur_folder.clone().join(&file_name);
-                if full_file_name
-                    .to_str()
-                    .map(|s| s.starts_with(prefix.as_ref()))
-                    .unwrap_or(false)
-                {
+            let mut entries = cur_folder.read_dir_utf8()?;
+            while let Some(Ok(entry)) = entries.next() {
+                let file_name = entry.file_name();
+                let full_file_name = cur_folder.join(file_name);
+                if full_file_name.as_str().starts_with(prefix) {
                     let file_remote_path = self.local_file_to_relative_path(full_file_name.clone());
-                    files.push(file_remote_path.clone());
+                    files.push(file_remote_path);
                     if full_file_name.is_dir() {
                         directory_queue.push(full_file_name);
                     }
@@ -230,10 +217,7 @@ impl RemoteStorage for LocalFs {
                 .open(&temp_file_path)
                 .await
                 .with_context(|| {
-                    format!(
-                        "Failed to open target fs destination at '{}'",
-                        target_file_path.display()
-                    )
+                    format!("Failed to open target fs destination at '{target_file_path}'")
                 })?,
         );
 
@@ -244,8 +228,7 @@ impl RemoteStorage for LocalFs {
             .await
             .with_context(|| {
                 format!(
-                    "Failed to upload file (write temp) to the local storage at '{}'",
-                    temp_file_path.display()
+                    "Failed to upload file (write temp) to the local storage at '{temp_file_path}'",
                 )
             })?;
 
@@ -262,8 +245,7 @@ impl RemoteStorage for LocalFs {
 
         destination.flush().await.with_context(|| {
             format!(
-                "Failed to upload (flush temp) file to the local storage at '{}'",
-                temp_file_path.display()
+                "Failed to upload (flush temp) file to the local storage at '{temp_file_path}'",
             )
         })?;
 
@@ -271,8 +253,7 @@ impl RemoteStorage for LocalFs {
             .await
             .with_context(|| {
                 format!(
-                    "Failed to upload (rename) file to the local storage at '{}'",
-                    target_file_path.display()
+                    "Failed to upload (rename) file to the local storage at '{target_file_path}'",
                 )
             })?;
 
@@ -286,8 +267,7 @@ impl RemoteStorage for LocalFs {
             .await
             .with_context(|| {
                 format!(
-                    "Failed to write metadata to the local storage at '{}'",
-                    storage_metadata_path.display()
+                    "Failed to write metadata to the local storage at '{storage_metadata_path}'",
                 )
             })?;
         }
@@ -393,16 +373,16 @@ impl RemoteStorage for LocalFs {
     }
 }
 
-fn storage_metadata_path(original_path: &Path) -> PathBuf {
+fn storage_metadata_path(original_path: &Utf8Path) -> Utf8PathBuf {
     path_with_suffix_extension(original_path, "metadata")
 }
 
 fn get_all_files<'a, P>(
     directory_path: P,
     recursive: bool,
-) -> Pin<Box<dyn Future<Output = anyhow::Result<Vec<PathBuf>>> + Send + Sync + 'a>>
+) -> Pin<Box<dyn Future<Output = anyhow::Result<Vec<Utf8PathBuf>>> + Send + Sync + 'a>>
 where
-    P: AsRef<Path> + Send + Sync + 'a,
+    P: AsRef<Utf8Path> + Send + Sync + 'a,
 {
     Box::pin(async move {
         let directory_path = directory_path.as_ref();
@@ -412,7 +392,13 @@ where
                 let mut dir_contents = fs::read_dir(directory_path).await?;
                 while let Some(dir_entry) = dir_contents.next_entry().await? {
                     let file_type = dir_entry.file_type().await?;
-                    let entry_path = dir_entry.path();
+                    let entry_path =
+                        Utf8PathBuf::from_path_buf(dir_entry.path()).map_err(|pb| {
+                            anyhow::Error::msg(format!(
+                                "non-Unicode path: {}",
+                                pb.to_string_lossy()
+                            ))
+                        })?;
                     if file_type.is_symlink() {
                         debug!("{entry_path:?} is a symlink, skipping")
                     } else if file_type.is_dir() {
@@ -435,13 +421,10 @@ where
     })
 }
 
-async fn create_target_directory(target_file_path: &Path) -> anyhow::Result<()> {
+async fn create_target_directory(target_file_path: &Utf8Path) -> anyhow::Result<()> {
     let target_dir = match target_file_path.parent() {
         Some(parent_dir) => parent_dir,
-        None => bail!(
-            "File path '{}' has no parent directory",
-            target_file_path.display()
-        ),
+        None => bail!("File path '{target_file_path}' has no parent directory"),
     };
     if !target_dir.exists() {
         fs::create_dir_all(target_dir).await?;
@@ -449,13 +432,9 @@ async fn create_target_directory(target_file_path: &Path) -> anyhow::Result<()>
     Ok(())
 }
 
-fn file_exists(file_path: &Path) -> anyhow::Result<bool> {
+fn file_exists(file_path: &Utf8Path) -> anyhow::Result<bool> {
     if file_path.exists() {
-        ensure!(
-            file_path.is_file(),
-            "file path '{}' is not a file",
-            file_path.display()
-        );
+        ensure!(file_path.is_file(), "file path '{file_path}' is not a file");
         Ok(true)
     } else {
         Ok(false)
@@ -466,13 +445,13 @@ fn file_exists(file_path: &Path) -> anyhow::Result<bool> {
 mod fs_tests {
     use super::*;
 
+    use camino_tempfile::tempdir;
     use std::{collections::HashMap, io::Write};
-    use tempfile::tempdir;
 
     async fn read_and_assert_remote_file_contents(
         storage: &LocalFs,
         #[allow(clippy::ptr_arg)]
-        // have to use &PathBuf due to `storage.local_path` parameter requirements
+        // have to use &Utf8PathBuf due to `storage.local_path` parameter requirements
         remote_storage_path: &RemotePath,
         expected_metadata: Option<&StorageMetadata>,
     ) -> anyhow::Result<String> {
@@ -519,7 +498,7 @@ mod fs_tests {
     async fn upload_file_negatives() -> anyhow::Result<()> {
         let storage = create_storage()?;
 
-        let id = RemotePath::new(Path::new("dummy"))?;
+        let id = RemotePath::new(Utf8Path::new("dummy"))?;
         let content = std::io::Cursor::new(b"12345");
 
         // Check that you get an error if the size parameter doesn't match the actual
@@ -544,7 +523,8 @@ mod fs_tests {
     }
 
     fn create_storage() -> anyhow::Result<LocalFs> {
-        LocalFs::new(tempdir()?.path().to_owned())
+        let storage_root = tempdir()?.path().to_path_buf();
+        LocalFs::new(storage_root)
     }
 
     #[tokio::test]
@@ -561,7 +541,7 @@ mod fs_tests {
         );
 
         let non_existing_path = "somewhere/else";
-        match storage.download(&RemotePath::new(Path::new(non_existing_path))?).await {
+        match storage.download(&RemotePath::new(Utf8Path::new(non_existing_path))?).await {
             Err(DownloadError::NotFound) => {} // Should get NotFound for non existing keys
             other => panic!("Should get a NotFound error when downloading non-existing storage files, but got: {other:?}"),
         }
@@ -775,7 +755,7 @@ mod fs_tests {
     }
 
     async fn create_file_for_upload(
-        path: &Path,
+        path: &Utf8Path,
         contents: &str,
     ) -> anyhow::Result<(io::BufReader<fs::File>, usize)> {
         std::fs::create_dir_all(path.parent().unwrap())?;

libs/remote_storage/src/s3_bucket.rs

@@ -180,12 +180,11 @@ impl S3Bucket {
         assert_eq!(std::path::MAIN_SEPARATOR, REMOTE_STORAGE_PREFIX_SEPARATOR);
         let path_string = path
             .get_path()
-            .to_string_lossy()
-            .trim_end_matches(REMOTE_STORAGE_PREFIX_SEPARATOR)
-            .to_string();
+            .as_str()
+            .trim_end_matches(REMOTE_STORAGE_PREFIX_SEPARATOR);
         match &self.prefix_in_bucket {
-            Some(prefix) => prefix.clone() + "/" + &path_string,
-            None => path_string,
+            Some(prefix) => prefix.clone() + "/" + path_string,
+            None => path_string.to_string(),
         }
     }
 
@@ -601,8 +600,8 @@ fn start_measuring_requests(
 
 #[cfg(test)]
 mod tests {
+    use camino::Utf8Path;
     use std::num::NonZeroUsize;
-    use std::path::Path;
 
     use crate::{RemotePath, S3Bucket, S3Config};
 
@@ -611,7 +610,7 @@ mod tests {
         let all_paths = ["", "some/path", "some/path/"];
         let all_paths: Vec<RemotePath> = all_paths
             .iter()
-            .map(|x| RemotePath::new(Path::new(x)).expect("bad path"))
+            .map(|x| RemotePath::new(Utf8Path::new(x)).expect("bad path"))
             .collect();
         let prefixes = [
             None,

libs/remote_storage/tests/test_real_s3.rs

@@ -2,11 +2,12 @@ use std::collections::HashSet;
 use std::env;
 use std::num::{NonZeroU32, NonZeroUsize};
 use std::ops::ControlFlow;
-use std::path::{Path, PathBuf};
+use std::path::PathBuf;
 use std::sync::Arc;
 use std::time::UNIX_EPOCH;
 
 use anyhow::Context;
+use camino::Utf8Path;
 use once_cell::sync::OnceCell;
 use remote_storage::{
     GenericRemoteStorage, RemotePath, RemoteStorageConfig, RemoteStorageKind, S3Config,
@@ -55,7 +56,7 @@ async fn s3_pagination_should_work(ctx: &mut MaybeEnabledS3WithTestBlobs) -> any
     let test_client = Arc::clone(&ctx.enabled.client);
     let expected_remote_prefixes = ctx.remote_prefixes.clone();
 
-    let base_prefix = RemotePath::new(Path::new(ctx.enabled.base_prefix))
+    let base_prefix = RemotePath::new(Utf8Path::new(ctx.enabled.base_prefix))
         .context("common_prefix construction")?;
     let root_remote_prefixes = test_client
         .list_prefixes(None)
@@ -108,7 +109,7 @@ async fn s3_list_files_works(ctx: &mut MaybeEnabledS3WithSimpleTestBlobs) -> any
     };
     let test_client = Arc::clone(&ctx.enabled.client);
     let base_prefix =
-        RemotePath::new(Path::new("folder1")).context("common_prefix construction")?;
+        RemotePath::new(Utf8Path::new("folder1")).context("common_prefix construction")?;
     let root_files = test_client
         .list_files(None)
         .await
@@ -129,9 +130,9 @@ async fn s3_list_files_works(ctx: &mut MaybeEnabledS3WithSimpleTestBlobs) -> any
     let trim_remote_blobs: HashSet<_> = ctx
         .remote_blobs
         .iter()
-        .map(|x| x.get_path().to_str().expect("must be valid name"))
+        .map(|x| x.get_path())
         .filter(|x| x.starts_with("folder1"))
-        .map(|x| RemotePath::new(Path::new(x)).expect("must be valid name"))
+        .map(|x| RemotePath::new(x).expect("must be valid path"))
         .collect();
     assert_eq!(
         nested_remote_files, trim_remote_blobs,
@@ -148,10 +149,9 @@ async fn s3_delete_non_exising_works(ctx: &mut MaybeEnabledS3) -> anyhow::Result
         MaybeEnabledS3::Disabled => return Ok(()),
     };
 
-    let path = RemotePath::new(&PathBuf::from(format!(
-        "{}/for_sure_there_is_nothing_there_really",
-        ctx.base_prefix,
-    )))
+    let path = RemotePath::new(Utf8Path::new(
+        format!("{}/for_sure_there_is_nothing_there_really", ctx.base_prefix).as_str(),
+    ))
     .with_context(|| "RemotePath conversion")?;
 
     ctx.client.delete(&path).await.expect("should succeed");
@@ -167,13 +167,13 @@ async fn s3_delete_objects_works(ctx: &mut MaybeEnabledS3) -> anyhow::Result<()>
         MaybeEnabledS3::Disabled => return Ok(()),
     };
 
-    let path1 = RemotePath::new(&PathBuf::from(format!("{}/path1", ctx.base_prefix,)))
+    let path1 = RemotePath::new(Utf8Path::new(format!("{}/path1", ctx.base_prefix).as_str()))
         .with_context(|| "RemotePath conversion")?;
 
-    let path2 = RemotePath::new(&PathBuf::from(format!("{}/path2", ctx.base_prefix,)))
+    let path2 = RemotePath::new(Utf8Path::new(format!("{}/path2", ctx.base_prefix).as_str()))
         .with_context(|| "RemotePath conversion")?;
 
-    let path3 = RemotePath::new(&PathBuf::from(format!("{}/path3", ctx.base_prefix,)))
+    let path3 = RemotePath::new(Utf8Path::new(format!("{}/path3", ctx.base_prefix).as_str()))
         .with_context(|| "RemotePath conversion")?;
 
     let data1 = "remote blob data1".as_bytes();
@@ -427,10 +427,10 @@ async fn upload_s3_data(
     for i in 1..upload_tasks_count + 1 {
         let task_client = Arc::clone(client);
         upload_tasks.spawn(async move {
-            let prefix = PathBuf::from(format!("{base_prefix_str}/sub_prefix_{i}/"));
-            let blob_prefix = RemotePath::new(&prefix)
+            let prefix = format!("{base_prefix_str}/sub_prefix_{i}/");
+            let blob_prefix = RemotePath::new(Utf8Path::new(&prefix))
                 .with_context(|| format!("{prefix:?} to RemotePath conversion"))?;
-            let blob_path = blob_prefix.join(Path::new(&format!("blob_{i}")));
+            let blob_path = blob_prefix.join(Utf8Path::new(&format!("blob_{i}")));
             debug!("Creating remote item {i} at path {blob_path:?}");
 
             let data = format!("remote blob data {i}").into_bytes();
@@ -512,8 +512,10 @@ async fn upload_simple_s3_data(
         let task_client = Arc::clone(client);
         upload_tasks.spawn(async move {
             let blob_path = PathBuf::from(format!("folder{}/blob_{}.txt", i / 7, i));
-            let blob_path = RemotePath::new(&blob_path)
-                .with_context(|| format!("{blob_path:?} to RemotePath conversion"))?;
+            let blob_path = RemotePath::new(
+                Utf8Path::from_path(blob_path.as_path()).expect("must be valid blob path"),
+            )
+            .with_context(|| format!("{blob_path:?} to RemotePath conversion"))?;
             debug!("Creating remote item {i} at path {blob_path:?}");
 
             let data = format!("remote blob data {i}").into_bytes();

libs/utils/Cargo.toml

@@ -10,6 +10,7 @@ async-trait.workspace = true
 anyhow.workspace = true
 bincode.workspace = true
 bytes.workspace = true
+camino.workspace = true
 chrono.workspace = true
 heapless.workspace = true
 hex = { workspace = true, features = ["serde"] }
@@ -53,7 +54,7 @@ byteorder.workspace = true
 bytes.workspace = true
 criterion.workspace = true
 hex-literal.workspace = true
-tempfile.workspace = true
+camino-tempfile.workspace = true
 
 [[bench]]
 name = "benchmarks"

libs/utils/src/auth.rs

@@ -2,9 +2,9 @@
 
 use serde;
 use std::fs;
-use std::path::Path;
 
 use anyhow::Result;
+use camino::Utf8Path;
 use jsonwebtoken::{
     decode, encode, Algorithm, DecodingKey, EncodingKey, Header, TokenData, Validation,
 };
@@ -65,7 +65,7 @@ impl JwtAuth {
         }
     }
 
-    pub fn from_key_path(key_path: &Path) -> Result<Self> {
+    pub fn from_key_path(key_path: &Utf8Path) -> Result<Self> {
         let public_key = fs::read(key_path)?;
         Ok(Self::new(DecodingKey::from_ed_pem(&public_key)?))
     }

libs/utils/src/crashsafe.rs

@@ -1,14 +1,14 @@
 use std::{
     borrow::Cow,
-    ffi::OsStr,
     fs::{self, File},
     io,
-    path::{Path, PathBuf},
 };
 
+use camino::{Utf8Path, Utf8PathBuf};
+
 /// Similar to [`std::fs::create_dir`], except we fsync the
 /// created directory and its parent.
-pub fn create_dir(path: impl AsRef<Path>) -> io::Result<()> {
+pub fn create_dir(path: impl AsRef<Utf8Path>) -> io::Result<()> {
     let path = path.as_ref();
 
     fs::create_dir(path)?;
@@ -18,7 +18,7 @@ pub fn create_dir(path: impl AsRef<Path>) -> io::Result<()> {
 
 /// Similar to [`std::fs::create_dir_all`], except we fsync all
 /// newly created directories and the pre-existing parent.
-pub fn create_dir_all(path: impl AsRef<Path>) -> io::Result<()> {
+pub fn create_dir_all(path: impl AsRef<Utf8Path>) -> io::Result<()> {
     let mut path = path.as_ref();
 
     let mut dirs_to_create = Vec::new();
@@ -30,7 +30,7 @@ pub fn create_dir_all(path: impl AsRef<Path>) -> io::Result<()> {
             Ok(_) => {
                 return Err(io::Error::new(
                     io::ErrorKind::AlreadyExists,
-                    format!("non-directory found in path: {}", path.display()),
+                    format!("non-directory found in path: {path}"),
                 ));
             }
             Err(ref e) if e.kind() == io::ErrorKind::NotFound => {}
@@ -44,7 +44,7 @@ pub fn create_dir_all(path: impl AsRef<Path>) -> io::Result<()> {
             None => {
                 return Err(io::Error::new(
                     io::ErrorKind::InvalidInput,
-                    format!("can't find parent of path '{}'", path.display()).as_str(),
+                    format!("can't find parent of path '{path}'"),
                 ));
             }
         }
@@ -70,21 +70,18 @@ pub fn create_dir_all(path: impl AsRef<Path>) -> io::Result<()> {
 
 /// Adds a suffix to the file(directory) name, either appending the suffix to the end of its extension,
 /// or if there's no extension, creates one and puts a suffix there.
-pub fn path_with_suffix_extension(original_path: impl AsRef<Path>, suffix: &str) -> PathBuf {
-    let new_extension = match original_path
-        .as_ref()
-        .extension()
-        .map(OsStr::to_string_lossy)
-    {
+pub fn path_with_suffix_extension(
+    original_path: impl AsRef<Utf8Path>,
+    suffix: &str,
+) -> Utf8PathBuf {
+    let new_extension = match original_path.as_ref().extension() {
         Some(extension) => Cow::Owned(format!("{extension}.{suffix}")),
         None => Cow::Borrowed(suffix),
     };
-    original_path
-        .as_ref()
-        .with_extension(new_extension.as_ref())
+    original_path.as_ref().with_extension(new_extension)
 }
 
-pub fn fsync_file_and_parent(file_path: &Path) -> io::Result<()> {
+pub fn fsync_file_and_parent(file_path: &Utf8Path) -> io::Result<()> {
     let parent = file_path.parent().ok_or_else(|| {
         io::Error::new(
             io::ErrorKind::Other,
@@ -97,7 +94,7 @@ pub fn fsync_file_and_parent(file_path: &Path) -> io::Result<()> {
     Ok(())
 }
 
-pub fn fsync(path: &Path) -> io::Result<()> {
+pub fn fsync(path: &Utf8Path) -> io::Result<()> {
     File::open(path)
         .map_err(|e| io::Error::new(e.kind(), format!("Failed to open the file {path:?}: {e}")))
         .and_then(|file| {
@@ -111,19 +108,18 @@ pub fn fsync(path: &Path) -> io::Result<()> {
         .map_err(|e| io::Error::new(e.kind(), format!("Failed to fsync file {path:?}: {e}")))
 }
 
-pub async fn fsync_async(path: impl AsRef<std::path::Path>) -> Result<(), std::io::Error> {
-    tokio::fs::File::open(path).await?.sync_all().await
+pub async fn fsync_async(path: impl AsRef<Utf8Path>) -> Result<(), std::io::Error> {
+    tokio::fs::File::open(path.as_ref()).await?.sync_all().await
 }
 
 #[cfg(test)]
 mod tests {
-    use tempfile::tempdir;
 
     use super::*;
 
     #[test]
     fn test_create_dir_fsyncd() {
-        let dir = tempdir().unwrap();
+        let dir = camino_tempfile::tempdir().unwrap();
 
         let existing_dir_path = dir.path();
         let err = create_dir(existing_dir_path).unwrap_err();
@@ -139,7 +135,7 @@ mod tests {
 
     #[test]
     fn test_create_dir_all_fsyncd() {
-        let dir = tempdir().unwrap();
+        let dir = camino_tempfile::tempdir().unwrap();
 
         let existing_dir_path = dir.path();
         create_dir_all(existing_dir_path).unwrap();
@@ -166,29 +162,29 @@ mod tests {
 
     #[test]
     fn test_path_with_suffix_extension() {
-        let p = PathBuf::from("/foo/bar");
+        let p = Utf8PathBuf::from("/foo/bar");
         assert_eq!(
-            &path_with_suffix_extension(p, "temp").to_string_lossy(),
+            &path_with_suffix_extension(p, "temp").to_string(),
             "/foo/bar.temp"
         );
-        let p = PathBuf::from("/foo/bar");
+        let p = Utf8PathBuf::from("/foo/bar");
         assert_eq!(
-            &path_with_suffix_extension(p, "temp.temp").to_string_lossy(),
+            &path_with_suffix_extension(p, "temp.temp").to_string(),
             "/foo/bar.temp.temp"
         );
-        let p = PathBuf::from("/foo/bar.baz");
+        let p = Utf8PathBuf::from("/foo/bar.baz");
         assert_eq!(
-            &path_with_suffix_extension(p, "temp.temp").to_string_lossy(),
+            &path_with_suffix_extension(p, "temp.temp").to_string(),
             "/foo/bar.baz.temp.temp"
         );
-        let p = PathBuf::from("/foo/bar.baz");
+        let p = Utf8PathBuf::from("/foo/bar.baz");
         assert_eq!(
-            &path_with_suffix_extension(p, ".temp").to_string_lossy(),
+            &path_with_suffix_extension(p, ".temp").to_string(),
             "/foo/bar.baz..temp"
         );
-        let p = PathBuf::from("/foo/bar/dir/");
+        let p = Utf8PathBuf::from("/foo/bar/dir/");
         assert_eq!(
-            &path_with_suffix_extension(p, ".temp").to_string_lossy(),
+            &path_with_suffix_extension(p, ".temp").to_string(),
             "/foo/bar/dir..temp"
         );
     }

libs/utils/src/fs_ext.rs

@@ -55,8 +55,6 @@ where
 
 #[cfg(test)]
 mod test {
-    use std::path::PathBuf;
-
     use crate::fs_ext::{is_directory_empty, list_dir};
 
     use super::ignore_absent_files;
@@ -65,7 +63,7 @@ mod test {
     fn is_empty_dir() {
         use super::PathExt;
 
-        let dir = tempfile::tempdir().unwrap();
+        let dir = camino_tempfile::tempdir().unwrap();
         let dir_path = dir.path();
 
         // test positive case
@@ -75,7 +73,7 @@ mod test {
         );
 
         // invoke on a file to ensure it returns an error
-        let file_path: PathBuf = dir_path.join("testfile");
+        let file_path = dir_path.join("testfile");
         let f = std::fs::File::create(&file_path).unwrap();
         drop(f);
         assert!(file_path.is_empty_dir().is_err());
@@ -87,7 +85,7 @@ mod test {
 
     #[tokio::test]
     async fn is_empty_dir_async() {
-        let dir = tempfile::tempdir().unwrap();
+        let dir = camino_tempfile::tempdir().unwrap();
         let dir_path = dir.path();
 
         // test positive case
@@ -97,7 +95,7 @@ mod test {
         );
 
         // invoke on a file to ensure it returns an error
-        let file_path: PathBuf = dir_path.join("testfile");
+        let file_path = dir_path.join("testfile");
         let f = std::fs::File::create(&file_path).unwrap();
         drop(f);
         assert!(is_directory_empty(&file_path).await.is_err());
@@ -109,10 +107,9 @@ mod test {
 
     #[test]
     fn ignore_absent_files_works() {
-        let dir = tempfile::tempdir().unwrap();
-        let dir_path = dir.path();
+        let dir = camino_tempfile::tempdir().unwrap();
 
-        let file_path: PathBuf = dir_path.join("testfile");
+        let file_path = dir.path().join("testfile");
 
         ignore_absent_files(|| std::fs::remove_file(&file_path)).expect("should execute normally");
 
@@ -126,17 +123,17 @@ mod test {
 
     #[tokio::test]
     async fn list_dir_works() {
-        let dir = tempfile::tempdir().unwrap();
+        let dir = camino_tempfile::tempdir().unwrap();
         let dir_path = dir.path();
 
         assert!(list_dir(dir_path).await.unwrap().is_empty());
 
-        let file_path: PathBuf = dir_path.join("testfile");
+        let file_path = dir_path.join("testfile");
         let _ = std::fs::File::create(&file_path).unwrap();
 
         assert_eq!(&list_dir(dir_path).await.unwrap(), &["testfile"]);
 
-        let another_dir_path: PathBuf = dir_path.join("testdir");
+        let another_dir_path = dir_path.join("testdir");
         std::fs::create_dir(another_dir_path).unwrap();
 
         let expected = &["testdir", "testfile"];

libs/utils/src/http/error.rs

@@ -24,6 +24,9 @@ pub enum ApiError {
     #[error("Precondition failed: {0}")]
     PreconditionFailed(Box<str>),
 
+    #[error("Resource temporarily unavailable: {0}")]
+    ResourceUnavailable(String),
+
     #[error("Shutting down")]
     ShuttingDown,
 
@@ -59,6 +62,10 @@ impl ApiError {
                 "Shutting down".to_string(),
                 StatusCode::SERVICE_UNAVAILABLE,
             ),
+            ApiError::ResourceUnavailable(err) => HttpErrorBody::response_from_msg_and_status(
+                err.to_string(),
+                StatusCode::SERVICE_UNAVAILABLE,
+            ),
             ApiError::InternalServerError(err) => HttpErrorBody::response_from_msg_and_status(
                 err.to_string(),
                 StatusCode::INTERNAL_SERVER_ERROR,

libs/utils/src/id.rs

@@ -1,4 +1,3 @@
-use std::ffi::OsStr;
 use std::{fmt, str::FromStr};
 
 use anyhow::Context;
@@ -215,12 +214,11 @@ pub struct TimelineId(Id);
 
 id_newtype!(TimelineId);
 
-impl TryFrom<Option<&OsStr>> for TimelineId {
+impl TryFrom<Option<&str>> for TimelineId {
     type Error = anyhow::Error;
 
-    fn try_from(value: Option<&OsStr>) -> Result<Self, Self::Error> {
+    fn try_from(value: Option<&str>) -> Result<Self, Self::Error> {
         value
-            .and_then(OsStr::to_str)
             .unwrap_or_default()
             .parse::<TimelineId>()
             .with_context(|| format!("Could not parse timeline id from {:?}", value))

libs/utils/src/lock_file.rs

@@ -11,10 +11,10 @@ use std::{
     io::{Read, Write},
     ops::Deref,
     os::unix::prelude::AsRawFd,
-    path::{Path, PathBuf},
 };
 
 use anyhow::Context;
+use camino::{Utf8Path, Utf8PathBuf};
 use nix::{errno::Errno::EAGAIN, fcntl};
 
 use crate::crashsafe;
@@ -23,7 +23,7 @@ use crate::crashsafe;
 /// Returned by [`create_exclusive`].
 #[must_use]
 pub struct UnwrittenLockFile {
-    path: PathBuf,
+    path: Utf8PathBuf,
     file: fs::File,
 }
 
@@ -60,7 +60,7 @@ impl UnwrittenLockFile {
 ///
 /// It is not an error if the file already exists.
 /// It is an error if the file is already locked.
-pub fn create_exclusive(lock_file_path: &Path) -> anyhow::Result<UnwrittenLockFile> {
+pub fn create_exclusive(lock_file_path: &Utf8Path) -> anyhow::Result<UnwrittenLockFile> {
     let lock_file = fs::OpenOptions::new()
         .create(true) // O_CREAT
         .write(true)
@@ -101,7 +101,7 @@ pub enum LockFileRead {
 /// Open & try to lock the lock file at the given `path`, returning a [handle][`LockFileRead`] to
 /// inspect its content. It is not an `Err(...)` if the file does not exist or is already locked.
 /// Check the [`LockFileRead`] variants for details.
-pub fn read_and_hold_lock_file(path: &Path) -> anyhow::Result<LockFileRead> {
+pub fn read_and_hold_lock_file(path: &Utf8Path) -> anyhow::Result<LockFileRead> {
     let res = fs::OpenOptions::new().read(true).open(path);
     let mut lock_file = match res {
         Ok(f) => f,

libs/utils/src/logging.rs

@@ -228,6 +228,12 @@ impl SecretString {
     }
 }
 
+impl From<String> for SecretString {
+    fn from(s: String) -> Self {
+        Self(s)
+    }
+}
+
 impl std::fmt::Debug for SecretString {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         write!(f, "[SECRET]")

libs/utils/src/lsn.rs

@@ -1,9 +1,9 @@
 #![warn(missing_docs)]
 
+use camino::Utf8Path;
 use serde::{Deserialize, Serialize};
 use std::fmt;
 use std::ops::{Add, AddAssign};
-use std::path::Path;
 use std::str::FromStr;
 use std::sync::atomic::{AtomicU64, Ordering};
 
@@ -44,11 +44,9 @@ impl Lsn {
     /// Parse an LSN from a filename in the form `0000000000000000`
     pub fn from_filename<F>(filename: F) -> Result<Self, LsnParseError>
     where
-        F: AsRef<Path>,
+        F: AsRef<Utf8Path>,
     {
-        let filename: &Path = filename.as_ref();
-        let filename = filename.to_str().ok_or(LsnParseError)?;
-        Lsn::from_hex(filename)
+        Lsn::from_hex(filename.as_ref().as_str())
     }
 
     /// Parse an LSN from a string in the form `0000000000000000`

libs/utils/src/pid_file.rs

@@ -49,9 +49,10 @@
 //! At this point, `B` and `C` are running, which is hazardous.
 //! Morale of the story: don't unlink pidfiles, ever.
 
-use std::{ops::Deref, path::Path};
+use std::ops::Deref;
 
 use anyhow::Context;
+use camino::Utf8Path;
 use nix::unistd::Pid;
 
 use crate::lock_file::{self, LockFileRead};
@@ -84,7 +85,7 @@ impl Deref for PidFileGuard {
 /// The claim ends as soon as the returned guard object is dropped.
 /// To maintain the claim for the remaining lifetime of the current process,
 /// use [`std::mem::forget`] or similar.
-pub fn claim_for_current_process(path: &Path) -> anyhow::Result<PidFileGuard> {
+pub fn claim_for_current_process(path: &Utf8Path) -> anyhow::Result<PidFileGuard> {
     let unwritten_lock_file = lock_file::create_exclusive(path).context("lock file")?;
     // if any of the next steps fail, we drop the file descriptor and thereby release the lock
     let guard = unwritten_lock_file
@@ -132,7 +133,7 @@ pub enum PidFileRead {
 ///
 /// On success, this function returns a [`PidFileRead`].
 /// Check its docs for a description of the meaning of its different variants.
-pub fn read(pidfile: &Path) -> anyhow::Result<PidFileRead> {
+pub fn read(pidfile: &Utf8Path) -> anyhow::Result<PidFileRead> {
     let res = lock_file::read_and_hold_lock_file(pidfile).context("read and hold pid file")?;
     let ret = match res {
         LockFileRead::NotExist => PidFileRead::NotExist,

libs/vm_monitor/src/runner.rs

@@ -4,9 +4,9 @@
 //! This is the "Monitor" part of the monitor binary and is the main entrypoint for
 //! all functionality.
 
+use std::fmt::Debug;
 use std::sync::Arc;
 use std::time::{Duration, Instant};
-use std::{fmt::Debug, mem};
 
 use anyhow::{bail, Context};
 use axum::extract::ws::{Message, WebSocket};
@@ -141,14 +141,6 @@ impl Runner {
             );
 
             state.cgroup = Some(cgroup);
-        } else {
-            // *NOTE*: We need to forget the sender so that its drop impl does not get ran.
-            // This allows us to poll it in `Monitor::run` regardless of whether we
-            // are managing a cgroup or not. If we don't forget it, all receives will
-            // immediately return an error because the sender is droped and it will
-            // claim all select! statements, effectively turning `Monitor::run` into
-            // `loop { fail to receive }`.
-            mem::forget(requesting_send);
         }
 
         let mut file_cache_reserved_bytes = 0;
@@ -417,7 +409,7 @@ impl Runner {
                     }
                 }
                 // we need to propagate an upscale request
-                request = self.dispatcher.request_upscale_events.recv() => {
+                request = self.dispatcher.request_upscale_events.recv(), if self.cgroup.is_some() => {
                     if request.is_none() {
                         bail!("failed to listen for upscale event from cgroup")
                     }

pageserver/Cargo.toml

@@ -12,11 +12,14 @@ testing = ["fail/failpoints"]
 
 [dependencies]
 anyhow.workspace = true
+async-channel.workspace = true
 async-compression.workspace = true
 async-stream.workspace = true
 async-trait.workspace = true
 byteorder.workspace = true
 bytes.workspace = true
+camino.workspace = true
+camino-tempfile.workspace = true
 chrono = { workspace = true, features = ["serde"] }
 clap = { workspace = true, features = ["string"] }
 close_fds.workspace = true
@@ -80,7 +83,6 @@ enum-map.workspace = true
 enumset.workspace = true
 strum.workspace = true
 strum_macros.workspace = true
-tempfile.workspace = true
 
 [dev-dependencies]
 criterion.workspace = true

pageserver/benches/bench_walredo.rs

@@ -25,7 +25,7 @@ fn redo_scenarios(c: &mut Criterion) {
     // input to the stderr.
     // utils::logging::init(utils::logging::LogFormat::Plain).unwrap();
 
-    let repo_dir = tempfile::tempdir_in(env!("CARGO_TARGET_TMPDIR")).unwrap();
+    let repo_dir = camino_tempfile::tempdir_in(env!("CARGO_TARGET_TMPDIR")).unwrap();
 
     let conf = PageServerConf::dummy_conf(repo_dir.path().to_path_buf());
     let conf = Box::leak(Box::new(conf));

pageserver/ctl/Cargo.toml

@@ -9,6 +9,7 @@ license.workspace = true
 [dependencies]
 anyhow.workspace = true
 bytes.workspace = true
+camino.workspace = true
 clap = { workspace = true, features = ["string"] }
 git-version.workspace = true
 pageserver = { path = ".." }

pageserver/ctl/src/layer_map_analyzer.rs

@@ -3,13 +3,14 @@
 //! Currently it only analyzes holes, which are regions within the layer range that the layer contains no updates for. In the future it might do more analysis (maybe key quantiles?) but it should never return sensitive data.
 
 use anyhow::Result;
+use camino::{Utf8Path, Utf8PathBuf};
 use pageserver::context::{DownloadBehavior, RequestContext};
 use pageserver::task_mgr::TaskKind;
 use pageserver::tenant::{TENANTS_SEGMENT_NAME, TIMELINES_SEGMENT_NAME};
 use std::cmp::Ordering;
 use std::collections::BinaryHeap;
 use std::ops::Range;
-use std::{fs, path::Path, str};
+use std::{fs, str};
 
 use pageserver::page_cache::PAGE_SZ;
 use pageserver::repository::{Key, KEY_SIZE};
@@ -98,7 +99,7 @@ pub(crate) fn parse_filename(name: &str) -> Option<LayerFile> {
 }
 
 // Finds the max_holes largest holes, ignoring any that are smaller than MIN_HOLE_LENGTH"
-async fn get_holes(path: &Path, max_holes: usize, ctx: &RequestContext) -> Result<Vec<Hole>> {
+async fn get_holes(path: &Utf8Path, max_holes: usize, ctx: &RequestContext) -> Result<Vec<Hole>> {
     let file = FileBlockReader::new(VirtualFile::open(path).await?);
     let summary_blk = file.read_blk(0, ctx).await?;
     let actual_summary = Summary::des_prefix(summary_blk.as_ref())?;
@@ -167,7 +168,9 @@ pub(crate) async fn main(cmd: &AnalyzeLayerMapCmd) -> Result<()> {
                     parse_filename(&layer.file_name().into_string().unwrap())
                 {
                     if layer_file.is_delta {
-                        layer_file.holes = get_holes(&layer.path(), max_holes, &ctx).await?;
+                        let layer_path =
+                            Utf8PathBuf::from_path_buf(layer.path()).expect("non-Unicode path");
+                        layer_file.holes = get_holes(&layer_path, max_holes, &ctx).await?;
                         n_deltas += 1;
                     }
                     layers.push(layer_file);

pageserver/ctl/src/layers.rs

@@ -1,6 +1,7 @@
 use std::path::{Path, PathBuf};
 
 use anyhow::Result;
+use camino::Utf8Path;
 use clap::Subcommand;
 use pageserver::context::{DownloadBehavior, RequestContext};
 use pageserver::task_mgr::TaskKind;
@@ -47,7 +48,7 @@ pub(crate) enum LayerCmd {
 }
 
 async fn read_delta_file(path: impl AsRef<Path>, ctx: &RequestContext) -> Result<()> {
-    let path = path.as_ref();
+    let path = Utf8Path::from_path(path.as_ref()).expect("non-Unicode path");
     virtual_file::init(10);
     page_cache::init(100);
     let file = FileBlockReader::new(VirtualFile::open(path).await?);

pageserver/ctl/src/main.rs

@@ -8,6 +8,7 @@ mod draw_timeline_dir;
 mod layer_map_analyzer;
 mod layers;
 
+use camino::{Utf8Path, Utf8PathBuf};
 use clap::{Parser, Subcommand};
 use layers::LayerCmd;
 use pageserver::{
@@ -18,7 +19,6 @@ use pageserver::{
     virtual_file,
 };
 use postgres_ffi::ControlFileData;
-use std::path::{Path, PathBuf};
 use utils::{lsn::Lsn, project_git_version};
 
 project_git_version!(GIT_VERSION);
@@ -49,7 +49,7 @@ enum Commands {
 #[derive(Parser)]
 struct MetadataCmd {
     /// Input metadata file path
-    metadata_path: PathBuf,
+    metadata_path: Utf8PathBuf,
     /// Replace disk consistent Lsn
     disk_consistent_lsn: Option<Lsn>,
     /// Replace previous record Lsn
@@ -61,13 +61,13 @@ struct MetadataCmd {
 #[derive(Parser)]
 struct PrintLayerFileCmd {
     /// Pageserver data path
-    path: PathBuf,
+    path: Utf8PathBuf,
 }
 
 #[derive(Parser)]
 struct AnalyzeLayerMapCmd {
     /// Pageserver data path
-    path: PathBuf,
+    path: Utf8PathBuf,
     /// Max holes
     max_holes: Option<usize>,
 }
@@ -102,7 +102,7 @@ async fn main() -> anyhow::Result<()> {
     Ok(())
 }
 
-fn read_pg_control_file(control_file_path: &Path) -> anyhow::Result<()> {
+fn read_pg_control_file(control_file_path: &Utf8Path) -> anyhow::Result<()> {
     let control_file = ControlFileData::decode(&std::fs::read(control_file_path)?)?;
     println!("{control_file:?}");
     let control_file_initdb = Lsn(control_file.checkPoint);
@@ -114,7 +114,7 @@ fn read_pg_control_file(control_file_path: &Path) -> anyhow::Result<()> {
     Ok(())
 }
 
-async fn print_layerfile(path: &Path) -> anyhow::Result<()> {
+async fn print_layerfile(path: &Utf8Path) -> anyhow::Result<()> {
     // Basic initialization of things that don't change after startup
     virtual_file::init(10);
     page_cache::init(100);

pageserver/src/bin/pageserver.rs

@@ -2,9 +2,10 @@
 
 use std::env::{var, VarError};
 use std::sync::Arc;
-use std::{env, ops::ControlFlow, path::Path, str::FromStr};
+use std::{env, ops::ControlFlow, str::FromStr};
 
 use anyhow::{anyhow, Context};
+use camino::Utf8Path;
 use clap::{Arg, ArgAction, Command};
 
 use metrics::launch_timestamp::{set_launch_timestamp_metric, LaunchTimestamp};
@@ -65,21 +66,17 @@ fn main() -> anyhow::Result<()> {
 
     let workdir = arg_matches
         .get_one::<String>("workdir")
-        .map(Path::new)
-        .unwrap_or_else(|| Path::new(".neon"));
+        .map(Utf8Path::new)
+        .unwrap_or_else(|| Utf8Path::new(".neon"));
     let workdir = workdir
-        .canonicalize()
-        .with_context(|| format!("Error opening workdir '{}'", workdir.display()))?;
+        .canonicalize_utf8()
+        .with_context(|| format!("Error opening workdir '{workdir}'"))?;
 
     let cfg_file_path = workdir.join("pageserver.toml");
 
     // Set CWD to workdir for non-daemon modes
-    env::set_current_dir(&workdir).with_context(|| {
-        format!(
-            "Failed to set application's current dir to '{}'",
-            workdir.display()
-        )
-    })?;
+    env::set_current_dir(&workdir)
+        .with_context(|| format!("Failed to set application's current dir to '{workdir}'"))?;
 
     let conf = match initialize_config(&cfg_file_path, arg_matches, &workdir)? {
         ControlFlow::Continue(conf) => conf,
@@ -115,12 +112,8 @@ fn main() -> anyhow::Result<()> {
 
     let tenants_path = conf.tenants_path();
     if !tenants_path.exists() {
-        utils::crashsafe::create_dir_all(conf.tenants_path()).with_context(|| {
-            format!(
-                "Failed to create tenants root dir at '{}'",
-                tenants_path.display()
-            )
-        })?;
+        utils::crashsafe::create_dir_all(conf.tenants_path())
+            .with_context(|| format!("Failed to create tenants root dir at '{tenants_path}'"))?;
     }
 
     // Initialize up failpoints support
@@ -137,9 +130,9 @@ fn main() -> anyhow::Result<()> {
 }
 
 fn initialize_config(
-    cfg_file_path: &Path,
+    cfg_file_path: &Utf8Path,
     arg_matches: clap::ArgMatches,
-    workdir: &Path,
+    workdir: &Utf8Path,
 ) -> anyhow::Result<ControlFlow<(), &'static PageServerConf>> {
     let init = arg_matches.get_flag("init");
     let update_config = init || arg_matches.get_flag("update-config");
@@ -147,33 +140,22 @@ fn initialize_config(
     let (mut toml, config_file_exists) = if cfg_file_path.is_file() {
         if init {
             anyhow::bail!(
-                "Config file '{}' already exists, cannot init it, use --update-config to update it",
-                cfg_file_path.display()
+                "Config file '{cfg_file_path}' already exists, cannot init it, use --update-config to update it",
             );
         }
         // Supplement the CLI arguments with the config file
-        let cfg_file_contents = std::fs::read_to_string(cfg_file_path).with_context(|| {
-            format!(
-                "Failed to read pageserver config at '{}'",
-                cfg_file_path.display()
-            )
-        })?;
+        let cfg_file_contents = std::fs::read_to_string(cfg_file_path)
+            .with_context(|| format!("Failed to read pageserver config at '{cfg_file_path}'"))?;
         (
             cfg_file_contents
                 .parse::<toml_edit::Document>()
                 .with_context(|| {
-                    format!(
-                        "Failed to parse '{}' as pageserver config",
-                        cfg_file_path.display()
-                    )
+                    format!("Failed to parse '{cfg_file_path}' as pageserver config")
                 })?,
             true,
         )
     } else if cfg_file_path.exists() {
-        anyhow::bail!(
-            "Config file '{}' exists but is not a regular file",
-            cfg_file_path.display()
-        );
+        anyhow::bail!("Config file '{cfg_file_path}' exists but is not a regular file");
     } else {
         // We're initializing the tenant, so there's no config file yet
         (
@@ -192,7 +174,7 @@ fn initialize_config(
 
             for (key, item) in doc.iter() {
                 if config_file_exists && update_config && key == "id" && toml.contains_key(key) {
-                    anyhow::bail!("Pageserver config file exists at '{}' and has node id already, it cannot be overridden", cfg_file_path.display());
+                    anyhow::bail!("Pageserver config file exists at '{cfg_file_path}' and has node id already, it cannot be overridden");
                 }
                 toml.insert(key, item.clone());
             }
@@ -204,18 +186,11 @@ fn initialize_config(
         .context("Failed to parse pageserver configuration")?;
 
     if update_config {
-        info!("Writing pageserver config to '{}'", cfg_file_path.display());
+        info!("Writing pageserver config to '{cfg_file_path}'");
 
-        std::fs::write(cfg_file_path, toml.to_string()).with_context(|| {
-            format!(
-                "Failed to write pageserver config to '{}'",
-                cfg_file_path.display()
-            )
-        })?;
-        info!(
-            "Config successfully written to '{}'",
-            cfg_file_path.display()
-        )
+        std::fs::write(cfg_file_path, toml.to_string())
+            .with_context(|| format!("Failed to write pageserver config to '{cfg_file_path}'"))?;
+        info!("Config successfully written to '{cfg_file_path}'")
     }
 
     Ok(if init {

pageserver/src/config.rs

@@ -16,13 +16,13 @@ use utils::logging::SecretString;
 use once_cell::sync::OnceCell;
 use reqwest::Url;
 use std::num::NonZeroUsize;
-use std::path::{Path, PathBuf};
 use std::str::FromStr;
 use std::sync::Arc;
 use std::time::Duration;
 use toml_edit;
 use toml_edit::{Document, Item};
 
+use camino::{Utf8Path, Utf8PathBuf};
 use postgres_backend::AuthType;
 use utils::{
     id::{NodeId, TenantId, TimelineId},
@@ -37,8 +37,8 @@ use crate::tenant::{
     TIMELINES_SEGMENT_NAME,
 };
 use crate::{
-    IGNORED_TENANT_FILE_NAME, METADATA_FILE_NAME, TENANT_CONFIG_NAME, TIMELINE_DELETE_MARK_SUFFIX,
-    TIMELINE_UNINIT_MARK_SUFFIX,
+    IGNORED_TENANT_FILE_NAME, METADATA_FILE_NAME, TENANT_CONFIG_NAME, TENANT_LOCATION_CONFIG_NAME,
+    TIMELINE_DELETE_MARK_SUFFIX, TIMELINE_UNINIT_MARK_SUFFIX,
 };
 
 pub mod defaults {
@@ -153,9 +153,9 @@ pub struct PageServerConf {
     // that during unit testing, because the current directory is global
     // to the process but different unit tests work on different
     // repositories.
-    pub workdir: PathBuf,
+    pub workdir: Utf8PathBuf,
 
-    pub pg_distrib_dir: PathBuf,
+    pub pg_distrib_dir: Utf8PathBuf,
 
     // Authentication
     /// authentication method for the HTTP mgmt API
@@ -164,7 +164,7 @@ pub struct PageServerConf {
     pub pg_auth_type: AuthType,
     /// Path to a file containing public key for verifying JWT tokens.
     /// Used for both mgmt and compute auth, if enabled.
-    pub auth_validation_public_key_path: Option<PathBuf>,
+    pub auth_validation_public_key_path: Option<Utf8PathBuf>,
 
     pub remote_storage_config: Option<RemoteStorageConfig>,
 
@@ -253,15 +253,15 @@ struct PageServerConfigBuilder {
     page_cache_size: BuilderValue<usize>,
     max_file_descriptors: BuilderValue<usize>,
 
-    workdir: BuilderValue<PathBuf>,
+    workdir: BuilderValue<Utf8PathBuf>,
 
-    pg_distrib_dir: BuilderValue<PathBuf>,
+    pg_distrib_dir: BuilderValue<Utf8PathBuf>,
 
     http_auth_type: BuilderValue<AuthType>,
     pg_auth_type: BuilderValue<AuthType>,
 
     //
-    auth_validation_public_key_path: BuilderValue<Option<PathBuf>>,
+    auth_validation_public_key_path: BuilderValue<Option<Utf8PathBuf>>,
     remote_storage_config: BuilderValue<Option<RemoteStorageConfig>>,
 
     id: BuilderValue<NodeId>,
@@ -305,10 +305,12 @@ impl Default for PageServerConfigBuilder {
             superuser: Set(DEFAULT_SUPERUSER.to_string()),
             page_cache_size: Set(DEFAULT_PAGE_CACHE_SIZE),
             max_file_descriptors: Set(DEFAULT_MAX_FILE_DESCRIPTORS),
-            workdir: Set(PathBuf::new()),
-            pg_distrib_dir: Set(env::current_dir()
-                .expect("cannot access current directory")
-                .join("pg_install")),
+            workdir: Set(Utf8PathBuf::new()),
+            pg_distrib_dir: Set(Utf8PathBuf::from_path_buf(
+                env::current_dir().expect("cannot access current directory"),
+            )
+            .expect("non-Unicode path")
+            .join("pg_install")),
             http_auth_type: Set(AuthType::Trust),
             pg_auth_type: Set(AuthType::Trust),
             auth_validation_public_key_path: Set(None),
@@ -390,11 +392,11 @@ impl PageServerConfigBuilder {
         self.max_file_descriptors = BuilderValue::Set(max_file_descriptors)
     }
 
-    pub fn workdir(&mut self, workdir: PathBuf) {
+    pub fn workdir(&mut self, workdir: Utf8PathBuf) {
         self.workdir = BuilderValue::Set(workdir)
     }
 
-    pub fn pg_distrib_dir(&mut self, pg_distrib_dir: PathBuf) {
+    pub fn pg_distrib_dir(&mut self, pg_distrib_dir: Utf8PathBuf) {
         self.pg_distrib_dir = BuilderValue::Set(pg_distrib_dir)
     }
 
@@ -408,7 +410,7 @@ impl PageServerConfigBuilder {
 
     pub fn auth_validation_public_key_path(
         &mut self,
-        auth_validation_public_key_path: Option<PathBuf>,
+        auth_validation_public_key_path: Option<Utf8PathBuf>,
     ) {
         self.auth_validation_public_key_path = BuilderValue::Set(auth_validation_public_key_path)
     }
@@ -485,6 +487,10 @@ impl PageServerConfigBuilder {
         self.control_plane_api = BuilderValue::Set(api)
     }
 
+    pub fn control_plane_api_token(&mut self, token: Option<SecretString>) {
+        self.control_plane_api_token = BuilderValue::Set(token)
+    }
+
     pub fn build(self) -> anyhow::Result<PageServerConf> {
         let concurrent_tenant_size_logical_size_queries = self
             .concurrent_tenant_size_logical_size_queries
@@ -585,15 +591,15 @@ impl PageServerConf {
     // Repository paths, relative to workdir.
     //
 
-    pub fn tenants_path(&self) -> PathBuf {
+    pub fn tenants_path(&self) -> Utf8PathBuf {
         self.workdir.join(TENANTS_SEGMENT_NAME)
     }
 
-    pub fn deletion_prefix(&self) -> PathBuf {
+    pub fn deletion_prefix(&self) -> Utf8PathBuf {
         self.workdir.join("deletion")
     }
 
-    pub fn deletion_list_path(&self, sequence: u64) -> PathBuf {
+    pub fn deletion_list_path(&self, sequence: u64) -> Utf8PathBuf {
         // Encode a version in the filename, so that if we ever switch away from JSON we can
         // increment this.
         const VERSION: u8 = 1;
@@ -602,7 +608,7 @@ impl PageServerConf {
             .join(format!("{sequence:016x}-{VERSION:02x}.list"))
     }
 
-    pub fn deletion_header_path(&self) -> PathBuf {
+    pub fn deletion_header_path(&self) -> Utf8PathBuf {
         // Encode a version in the filename, so that if we ever switch away from JSON we can
         // increment this.
         const VERSION: u8 = 1;
@@ -610,30 +616,38 @@ impl PageServerConf {
         self.deletion_prefix().join(format!("header-{VERSION:02x}"))
     }
 
-    pub fn tenant_path(&self, tenant_id: &TenantId) -> PathBuf {
+    pub fn tenant_path(&self, tenant_id: &TenantId) -> Utf8PathBuf {
         self.tenants_path().join(tenant_id.to_string())
     }
 
-    pub fn tenant_attaching_mark_file_path(&self, tenant_id: &TenantId) -> PathBuf {
+    pub fn tenant_attaching_mark_file_path(&self, tenant_id: &TenantId) -> Utf8PathBuf {
         self.tenant_path(tenant_id)
             .join(TENANT_ATTACHING_MARKER_FILENAME)
     }
 
-    pub fn tenant_ignore_mark_file_path(&self, tenant_id: &TenantId) -> PathBuf {
+    pub fn tenant_ignore_mark_file_path(&self, tenant_id: &TenantId) -> Utf8PathBuf {
         self.tenant_path(tenant_id).join(IGNORED_TENANT_FILE_NAME)
     }
 
     /// Points to a place in pageserver's local directory,
     /// where certain tenant's tenantconf file should be located.
-    pub fn tenant_config_path(&self, tenant_id: &TenantId) -> PathBuf {
+    ///
+    /// Legacy: superseded by tenant_location_config_path.  Eventually
+    /// remove this function.
+    pub fn tenant_config_path(&self, tenant_id: &TenantId) -> Utf8PathBuf {
         self.tenant_path(tenant_id).join(TENANT_CONFIG_NAME)
     }
 
-    pub fn timelines_path(&self, tenant_id: &TenantId) -> PathBuf {
+    pub fn tenant_location_config_path(&self, tenant_id: &TenantId) -> Utf8PathBuf {
+        self.tenant_path(tenant_id)
+            .join(TENANT_LOCATION_CONFIG_NAME)
+    }
+
+    pub fn timelines_path(&self, tenant_id: &TenantId) -> Utf8PathBuf {
         self.tenant_path(tenant_id).join(TIMELINES_SEGMENT_NAME)
     }
 
-    pub fn timeline_path(&self, tenant_id: &TenantId, timeline_id: &TimelineId) -> PathBuf {
+    pub fn timeline_path(&self, tenant_id: &TenantId, timeline_id: &TimelineId) -> Utf8PathBuf {
         self.timelines_path(tenant_id).join(timeline_id.to_string())
     }
 
@@ -641,7 +655,7 @@ impl PageServerConf {
         &self,
         tenant_id: TenantId,
         timeline_id: TimelineId,
-    ) -> PathBuf {
+    ) -> Utf8PathBuf {
         path_with_suffix_extension(
             self.timeline_path(&tenant_id, &timeline_id),
             TIMELINE_UNINIT_MARK_SUFFIX,
@@ -652,19 +666,19 @@ impl PageServerConf {
         &self,
         tenant_id: TenantId,
         timeline_id: TimelineId,
-    ) -> PathBuf {
+    ) -> Utf8PathBuf {
         path_with_suffix_extension(
             self.timeline_path(&tenant_id, &timeline_id),
             TIMELINE_DELETE_MARK_SUFFIX,
         )
     }
 
-    pub fn tenant_deleted_mark_file_path(&self, tenant_id: &TenantId) -> PathBuf {
+    pub fn tenant_deleted_mark_file_path(&self, tenant_id: &TenantId) -> Utf8PathBuf {
         self.tenant_path(tenant_id)
             .join(TENANT_DELETED_MARKER_FILE_NAME)
     }
 
-    pub fn traces_path(&self) -> PathBuf {
+    pub fn traces_path(&self) -> Utf8PathBuf {
         self.workdir.join("traces")
     }
 
@@ -673,7 +687,7 @@ impl PageServerConf {
         tenant_id: &TenantId,
         timeline_id: &TimelineId,
         connection_id: &ConnectionId,
-    ) -> PathBuf {
+    ) -> Utf8PathBuf {
         self.traces_path()
             .join(tenant_id.to_string())
             .join(timeline_id.to_string())
@@ -682,20 +696,20 @@ impl PageServerConf {
 
     /// Points to a place in pageserver's local directory,
     /// where certain timeline's metadata file should be located.
-    pub fn metadata_path(&self, tenant_id: &TenantId, timeline_id: &TimelineId) -> PathBuf {
+    pub fn metadata_path(&self, tenant_id: &TenantId, timeline_id: &TimelineId) -> Utf8PathBuf {
         self.timeline_path(tenant_id, timeline_id)
             .join(METADATA_FILE_NAME)
     }
 
     /// Turns storage remote path of a file into its local path.
-    pub fn local_path(&self, remote_path: &RemotePath) -> PathBuf {
+    pub fn local_path(&self, remote_path: &RemotePath) -> Utf8PathBuf {
         remote_path.with_base(&self.workdir)
     }
 
     //
     // Postgres distribution paths
     //
-    pub fn pg_distrib_dir(&self, pg_version: u32) -> anyhow::Result<PathBuf> {
+    pub fn pg_distrib_dir(&self, pg_version: u32) -> anyhow::Result<Utf8PathBuf> {
         let path = self.pg_distrib_dir.clone();
 
         #[allow(clippy::manual_range_patterns)]
@@ -705,10 +719,10 @@ impl PageServerConf {
         }
     }
 
-    pub fn pg_bin_dir(&self, pg_version: u32) -> anyhow::Result<PathBuf> {
+    pub fn pg_bin_dir(&self, pg_version: u32) -> anyhow::Result<Utf8PathBuf> {
         Ok(self.pg_distrib_dir(pg_version)?.join("bin"))
     }
-    pub fn pg_lib_dir(&self, pg_version: u32) -> anyhow::Result<PathBuf> {
+    pub fn pg_lib_dir(&self, pg_version: u32) -> anyhow::Result<Utf8PathBuf> {
         Ok(self.pg_distrib_dir(pg_version)?.join("lib"))
     }
 
@@ -716,7 +730,7 @@ impl PageServerConf {
     /// validating the input and failing on errors.
     ///
     /// This leaves any options not present in the file in the built-in defaults.
-    pub fn parse_and_validate(toml: &Document, workdir: &Path) -> anyhow::Result<Self> {
+    pub fn parse_and_validate(toml: &Document, workdir: &Utf8Path) -> anyhow::Result<Self> {
         let mut builder = PageServerConfigBuilder::default();
         builder.workdir(workdir.to_owned());
 
@@ -735,10 +749,10 @@ impl PageServerConf {
                     builder.max_file_descriptors(parse_toml_u64(key, item)? as usize)
                 }
                 "pg_distrib_dir" => {
-                    builder.pg_distrib_dir(PathBuf::from(parse_toml_string(key, item)?))
+                    builder.pg_distrib_dir(Utf8PathBuf::from(parse_toml_string(key, item)?))
                 }
                 "auth_validation_public_key_path" => builder.auth_validation_public_key_path(Some(
-                    PathBuf::from(parse_toml_string(key, item)?),
+                    Utf8PathBuf::from(parse_toml_string(key, item)?),
                 )),
                 "http_auth_type" => builder.http_auth_type(parse_toml_from_str(key, item)?),
                 "pg_auth_type" => builder.pg_auth_type(parse_toml_from_str(key, item)?),
@@ -785,6 +799,14 @@ impl PageServerConf {
                         builder.control_plane_api(Some(parsed.parse().context("failed to parse control plane URL")?))
                     }
                 },
+                "control_plane_api_token" => {
+                    let parsed = parse_toml_string(key, item)?;
+                    if parsed.is_empty() {
+                        builder.control_plane_api_token(None)
+                    } else {
+                        builder.control_plane_api_token(Some(parsed.into()))
+                    }
+                },
                 _ => bail!("unrecognized pageserver option '{key}'"),
             }
         }
@@ -798,8 +820,7 @@ impl PageServerConf {
             ensure!(
                 auth_validation_public_key_path.exists(),
                 format!(
-                    "Can't find auth_validation_public_key at '{}'",
-                    auth_validation_public_key_path.display()
+                    "Can't find auth_validation_public_key at '{auth_validation_public_key_path}'",
                 )
             );
         }
@@ -915,12 +936,12 @@ impl PageServerConf {
     }
 
     #[cfg(test)]
-    pub fn test_repo_dir(test_name: &str) -> PathBuf {
-        PathBuf::from(format!("../tmp_check/test_{test_name}"))
+    pub fn test_repo_dir(test_name: &str) -> Utf8PathBuf {
+        Utf8PathBuf::from(format!("../tmp_check/test_{test_name}"))
     }
 
-    pub fn dummy_conf(repo_dir: PathBuf) -> Self {
-        let pg_distrib_dir = PathBuf::from(env!("CARGO_MANIFEST_DIR")).join("../pg_install");
+    pub fn dummy_conf(repo_dir: Utf8PathBuf) -> Self {
+        let pg_distrib_dir = Utf8PathBuf::from(env!("CARGO_MANIFEST_DIR")).join("../pg_install");
 
         PageServerConf {
             id: NodeId(0),
@@ -1087,8 +1108,8 @@ mod tests {
         num::{NonZeroU32, NonZeroUsize},
     };
 
+    use camino_tempfile::{tempdir, Utf8TempDir};
     use remote_storage::{RemoteStorageKind, S3Config};
-    use tempfile::{tempdir, TempDir};
     use utils::serde_percent::Percent;
 
     use super::*;
@@ -1127,8 +1148,7 @@ background_task_maximum_delay = '334 s'
         let broker_endpoint = storage_broker::DEFAULT_ENDPOINT;
         // we have to create dummy values to overcome the validation errors
         let config_string = format!(
-            "pg_distrib_dir='{}'\nid=10\nbroker_endpoint = '{broker_endpoint}'",
-            pg_distrib_dir.display()
+            "pg_distrib_dir='{pg_distrib_dir}'\nid=10\nbroker_endpoint = '{broker_endpoint}'",
         );
         let toml = config_string.parse()?;
 
@@ -1194,8 +1214,7 @@ background_task_maximum_delay = '334 s'
         let broker_endpoint = storage_broker::DEFAULT_ENDPOINT;
 
         let config_string = format!(
-            "{ALL_BASE_VALUES_TOML}pg_distrib_dir='{}'\nbroker_endpoint = '{broker_endpoint}'",
-            pg_distrib_dir.display()
+            "{ALL_BASE_VALUES_TOML}pg_distrib_dir='{pg_distrib_dir}'\nbroker_endpoint = '{broker_endpoint}'",
         );
         let toml = config_string.parse()?;
 
@@ -1255,23 +1274,18 @@ background_task_maximum_delay = '334 s'
         let identical_toml_declarations = &[
             format!(
                 r#"[remote_storage]
-local_path = '{}'"#,
-                local_storage_path.display()
-            ),
-            format!(
-                "remote_storage={{local_path='{}'}}",
-                local_storage_path.display()
+local_path = '{local_storage_path}'"#,
             ),
+            format!("remote_storage={{local_path='{local_storage_path}'}}"),
         ];
 
         for remote_storage_config_str in identical_toml_declarations {
             let config_string = format!(
                 r#"{ALL_BASE_VALUES_TOML}
-pg_distrib_dir='{}'
+pg_distrib_dir='{pg_distrib_dir}'
 broker_endpoint = '{broker_endpoint}'
 
 {remote_storage_config_str}"#,
-                pg_distrib_dir.display(),
             );
 
             let toml = config_string.parse()?;
@@ -1334,11 +1348,10 @@ concurrency_limit = {s3_concurrency_limit}"#
         for remote_storage_config_str in identical_toml_declarations {
             let config_string = format!(
                 r#"{ALL_BASE_VALUES_TOML}
-pg_distrib_dir='{}'
+pg_distrib_dir='{pg_distrib_dir}'
 broker_endpoint = '{broker_endpoint}'
 
 {remote_storage_config_str}"#,
-                pg_distrib_dir.display(),
             );
 
             let toml = config_string.parse()?;
@@ -1380,12 +1393,11 @@ broker_endpoint = '{broker_endpoint}'
 
         let config_string = format!(
             r#"{ALL_BASE_VALUES_TOML}
-pg_distrib_dir='{}'
+pg_distrib_dir='{pg_distrib_dir}'
 broker_endpoint = '{broker_endpoint}'
 
 [tenant_config]
 trace_read_requests = {trace_read_requests}"#,
-            pg_distrib_dir.display(),
         );
 
         let toml = config_string.parse()?;
@@ -1405,7 +1417,7 @@ trace_read_requests = {trace_read_requests}"#,
         let (workdir, pg_distrib_dir) = prepare_fs(&tempdir)?;
 
         let pageserver_conf_toml = format!(
-            r#"pg_distrib_dir = "{}"
+            r#"pg_distrib_dir = "{pg_distrib_dir}"
 metric_collection_endpoint = "http://sample.url"
 metric_collection_interval = "10min"
 id = 222
@@ -1423,7 +1435,6 @@ kind = "LayerAccessThreshold"
 period = "20m"
 threshold = "20m"
 "#,
-            pg_distrib_dir.display(),
         );
         let toml: Document = pageserver_conf_toml.parse()?;
         let conf = PageServerConf::parse_and_validate(&toml, &workdir)?;
@@ -1464,7 +1475,7 @@ threshold = "20m"
         Ok(())
     }
 
-    fn prepare_fs(tempdir: &TempDir) -> anyhow::Result<(PathBuf, PathBuf)> {
+    fn prepare_fs(tempdir: &Utf8TempDir) -> anyhow::Result<(Utf8PathBuf, Utf8PathBuf)> {
         let tempdir_path = tempdir.path();
 
         let workdir = tempdir_path.join("workdir");

pageserver/src/consumption_metrics.rs

@@ -3,11 +3,11 @@
 use crate::context::{DownloadBehavior, RequestContext};
 use crate::task_mgr::{self, TaskKind, BACKGROUND_RUNTIME};
 use crate::tenant::{mgr, LogicalSizeCalculationCause};
+use camino::Utf8PathBuf;
 use consumption_metrics::EventType;
 use pageserver_api::models::TenantState;
 use reqwest::Url;
 use std::collections::HashMap;
-use std::path::PathBuf;
 use std::sync::Arc;
 use std::time::{Duration, SystemTime};
 use tracing::*;
@@ -41,7 +41,7 @@ pub async fn collect_metrics(
     _cached_metric_collection_interval: Duration,
     synthetic_size_calculation_interval: Duration,
     node_id: NodeId,
-    local_disk_storage: PathBuf,
+    local_disk_storage: Utf8PathBuf,
     ctx: RequestContext,
 ) -> anyhow::Result<()> {
     if _cached_metric_collection_interval != Duration::ZERO {
@@ -68,7 +68,7 @@ pub async fn collect_metrics(
         },
     );
 
-    let path: Arc<PathBuf> = Arc::new(local_disk_storage);
+    let path: Arc<Utf8PathBuf> = Arc::new(local_disk_storage);
 
     let cancel = task_mgr::shutdown_token();
 
@@ -153,7 +153,7 @@ pub async fn collect_metrics(
 ///
 /// Cancellation safe.
 async fn restore_and_reschedule(
-    path: &Arc<PathBuf>,
+    path: &Arc<Utf8PathBuf>,
     metric_collection_interval: Duration,
 ) -> Cache {
     let (cached, earlier_metric_at) = match disk_cache::read_metrics_from_disk(path.clone()).await {

pageserver/src/consumption_metrics/disk_cache.rs

@@ -1,10 +1,12 @@
 use anyhow::Context;
-use std::path::PathBuf;
+use camino::{Utf8Path, Utf8PathBuf};
 use std::sync::Arc;
 
 use super::RawMetric;
 
-pub(super) async fn read_metrics_from_disk(path: Arc<PathBuf>) -> anyhow::Result<Vec<RawMetric>> {
+pub(super) async fn read_metrics_from_disk(
+    path: Arc<Utf8PathBuf>,
+) -> anyhow::Result<Vec<RawMetric>> {
     // do not add context to each error, callsite will log with full path
     let span = tracing::Span::current();
     tokio::task::spawn_blocking(move || {
@@ -25,10 +27,10 @@ pub(super) async fn read_metrics_from_disk(path: Arc<PathBuf>) -> anyhow::Result
     .and_then(|x| x)
 }
 
-fn scan_and_delete_with_same_prefix(path: &std::path::Path) -> std::io::Result<()> {
+fn scan_and_delete_with_same_prefix(path: &Utf8Path) -> std::io::Result<()> {
     let it = std::fs::read_dir(path.parent().expect("caller checked"))?;
 
-    let prefix = path.file_name().expect("caller checked").to_string_lossy();
+    let prefix = path.file_name().expect("caller checked").to_string();
 
     for entry in it {
         let entry = entry?;
@@ -62,7 +64,7 @@ fn scan_and_delete_with_same_prefix(path: &std::path::Path) -> std::io::Result<(
 
 pub(super) async fn flush_metrics_to_disk(
     current_metrics: &Arc<Vec<RawMetric>>,
-    path: &Arc<PathBuf>,
+    path: &Arc<Utf8PathBuf>,
 ) -> anyhow::Result<()> {
     use std::io::Write;
 
@@ -81,7 +83,7 @@ pub(super) async fn flush_metrics_to_disk(
 
             let parent = path.parent().expect("existence checked");
             let file_name = path.file_name().expect("existence checked");
-            let mut tempfile = tempfile::Builder::new()
+            let mut tempfile = camino_tempfile::Builder::new()
                 .prefix(file_name)
                 .suffix(".tmp")
                 .tempfile_in(parent)?;

pageserver/src/context.rs

@@ -86,15 +86,18 @@
 //! [`RequestContext`] argument. Functions in the middle of the call chain
 //! only need to pass it on.
 
+use std::sync::{Arc, Mutex, MutexGuard};
+
 use crate::task_mgr::TaskKind;
 
 // The main structure of this module, see module-level comment.
-#[derive(Clone, Debug)]
+#[derive(Clone)]
 pub struct RequestContext {
     task_kind: TaskKind,
     download_behavior: DownloadBehavior,
     access_stats_behavior: AccessStatsBehavior,
     page_content_kind: PageContentKind,
+    page_cache_permit: Option<Arc<crate::page_cache::PinnedSlotsPermit>>,
 }
 
 /// The kind of access to the page cache.
@@ -150,6 +153,7 @@ impl RequestContextBuilder {
                 download_behavior: DownloadBehavior::Download,
                 access_stats_behavior: AccessStatsBehavior::Update,
                 page_content_kind: PageContentKind::Unknown,
+                page_cache_permit: None,
             },
         }
     }
@@ -163,6 +167,7 @@ impl RequestContextBuilder {
                 download_behavior: original.download_behavior,
                 access_stats_behavior: original.access_stats_behavior,
                 page_content_kind: original.page_content_kind,
+                page_cache_permit: original.page_cache_permit.clone(),
             },
         }
     }
@@ -186,6 +191,11 @@ impl RequestContextBuilder {
         self
     }
 
+    pub(crate) fn page_cache_permit(mut self, p: Arc<crate::page_cache::PinnedSlotsPermit>) -> Self {
+        self.inner.page_cache_permit = Some(p);
+        self
+    }
+
     pub fn build(self) -> RequestContext {
         self.inner
     }
@@ -286,4 +296,8 @@ impl RequestContext {
     pub(crate) fn page_content_kind(&self) -> PageContentKind {
         self.page_content_kind
     }
+
+    pub(crate) fn permit(&self) -> Option<&crate::page_cache::PinnedSlotsPermit> {
+        self.page_cache_permit.as_ref().map(|p| &**p)
+    }
 }

pageserver/src/deletion_queue.rs

@@ -3,7 +3,6 @@ mod list_writer;
 mod validator;
 
 use std::collections::HashMap;
-use std::path::PathBuf;
 use std::sync::Arc;
 use std::time::Duration;
 
@@ -13,6 +12,7 @@ use crate::tenant::remote_timeline_client::remote_layer_path;
 use crate::tenant::remote_timeline_client::remote_timeline_path;
 use crate::virtual_file::VirtualFile;
 use anyhow::Context;
+use camino::Utf8PathBuf;
 use hex::FromHex;
 use remote_storage::{GenericRemoteStorage, RemotePath};
 use serde::Deserialize;
@@ -336,7 +336,6 @@ impl DeletionList {
         timeline_entry.extend(objects.drain(..).map(|p| {
             p.strip_prefix(&timeline_remote_path)
                 .expect("Timeline paths always start with the timeline prefix")
-                .to_string_lossy()
                 .to_string()
         }));
         true
@@ -350,7 +349,7 @@ impl DeletionList {
                 result.extend(
                     timeline_layers
                         .into_iter()
-                        .map(|l| timeline_remote_path.join(&PathBuf::from(l))),
+                        .map(|l| timeline_remote_path.join(&Utf8PathBuf::from(l))),
                 );
             }
         }
@@ -727,12 +726,9 @@ impl DeletionQueue {
 
 #[cfg(test)]
 mod test {
+    use camino::Utf8Path;
     use hex_literal::hex;
-    use std::{
-        io::ErrorKind,
-        path::{Path, PathBuf},
-        time::Duration,
-    };
+    use std::{io::ErrorKind, time::Duration};
     use tracing::info;
 
     use remote_storage::{RemoteStorageConfig, RemoteStorageKind};
@@ -764,7 +760,7 @@ mod test {
 
     struct TestSetup {
         harness: TenantHarness,
-        remote_fs_dir: PathBuf,
+        remote_fs_dir: Utf8PathBuf,
         storage: GenericRemoteStorage,
         mock_control_plane: MockControlPlane,
         deletion_queue: DeletionQueue,
@@ -873,7 +869,7 @@ mod test {
         // Set up a GenericRemoteStorage targetting a directory
         let remote_fs_dir = harness.conf.workdir.join("remote_fs");
         std::fs::create_dir_all(remote_fs_dir)?;
-        let remote_fs_dir = std::fs::canonicalize(harness.conf.workdir.join("remote_fs"))?;
+        let remote_fs_dir = harness.conf.workdir.join("remote_fs").canonicalize_utf8()?;
         let storage_config = RemoteStorageConfig {
             max_concurrent_syncs: std::num::NonZeroUsize::new(
                 remote_storage::DEFAULT_REMOTE_STORAGE_MAX_CONCURRENT_SYNCS,
@@ -909,7 +905,7 @@ mod test {
     }
 
     // TODO: put this in a common location so that we can share with remote_timeline_client's tests
-    fn assert_remote_files(expected: &[&str], remote_path: &Path) {
+    fn assert_remote_files(expected: &[&str], remote_path: &Utf8Path) {
         let mut expected: Vec<String> = expected.iter().map(|x| String::from(*x)).collect();
         expected.sort();
 
@@ -926,10 +922,7 @@ mod test {
                         unreachable!();
                     }
                 } else {
-                    panic!(
-                        "Unexpected error listing {}: {e}",
-                        remote_path.to_string_lossy()
-                    );
+                    panic!("Unexpected error listing {remote_path}: {e}");
                 }
             }
         };
@@ -944,7 +937,7 @@ mod test {
         assert_eq!(expected, found);
     }
 
-    fn assert_local_files(expected: &[&str], directory: &Path) {
+    fn assert_local_files(expected: &[&str], directory: &Utf8Path) {
         let dir = match std::fs::read_dir(directory) {
             Ok(d) => d,
             Err(_) => {

pageserver/src/deletion_queue/list_writer.rs

@@ -180,8 +180,7 @@ impl ListWriter {
                     Ok(h) => Ok(Some(h.validated_sequence)),
                     Err(e) => {
                         warn!(
-                            "Failed to deserialize deletion header, ignoring {}: {e:#}",
-                            header_path.display()
+                            "Failed to deserialize deletion header, ignoring {header_path}: {e:#}",
                         );
                         // This should never happen unless we make a mistake with our serialization.
                         // Ignoring a deletion header is not consequential for correctnes because all deletions
@@ -193,10 +192,7 @@ impl ListWriter {
             }
             Err(e) => {
                 if e.kind() == std::io::ErrorKind::NotFound {
-                    debug!(
-                        "Deletion header {} not found, first start?",
-                        header_path.display()
-                    );
+                    debug!("Deletion header {header_path} not found, first start?");
                     Ok(None)
                 } else {
                     Err(anyhow::anyhow!(e))
@@ -223,10 +219,7 @@ impl ListWriter {
         let mut dir = match tokio::fs::read_dir(&deletion_directory).await {
             Ok(d) => d,
             Err(e) => {
-                warn!(
-                    "Failed to open deletion list directory {}: {e:#}",
-                    deletion_directory.display(),
-                );
+                warn!("Failed to open deletion list directory {deletion_directory}: {e:#}");
 
                 // Give up: if we can't read the deletion list directory, we probably can't
                 // write lists into it later, so the queue won't work.
@@ -243,21 +236,19 @@ impl ListWriter {
             let file_name = dentry.file_name();
             let dentry_str = file_name.to_string_lossy();
 
-            if Some(file_name.as_os_str()) == header_path.file_name() {
+            if file_name == header_path.file_name().unwrap_or("") {
                 // Don't try and parse the header's name like a list
                 continue;
             }
 
             if dentry_str.ends_with(TEMP_SUFFIX) {
                 info!("Cleaning up temporary file {dentry_str}");
-                let absolute_path = deletion_directory.join(dentry.file_name());
+                let absolute_path =
+                    deletion_directory.join(dentry.file_name().to_str().expect("non-Unicode path"));
                 if let Err(e) = tokio::fs::remove_file(&absolute_path).await {
                     // Non-fatal error: we will just leave the file behind but not
                     // try and load it.
-                    warn!(
-                        "Failed to clean up temporary file {}: {e:#}",
-                        absolute_path.display()
-                    );
+                    warn!("Failed to clean up temporary file {absolute_path}: {e:#}");
                 }
 
                 continue;
@@ -360,7 +351,7 @@ impl ListWriter {
         if let Err(e) = create_dir_all(&self.conf.deletion_prefix()) {
             tracing::error!(
                 "Failed to create deletion list directory {}, deletions will not be executed ({e})",
-                self.conf.deletion_prefix().display()
+                self.conf.deletion_prefix(),
             );
             metrics::DELETION_QUEUE.unexpected_errors.inc();
             return;

pageserver/src/deletion_queue/validator.rs

@@ -15,10 +15,10 @@
 //! Deletions are passed onward to the Deleter.
 
 use std::collections::HashMap;
-use std::path::PathBuf;
 use std::sync::Arc;
 use std::time::Duration;
 
+use camino::Utf8PathBuf;
 use tokio_util::sync::CancellationToken;
 use tracing::debug;
 use tracing::info;
@@ -282,16 +282,16 @@ where
         Ok(())
     }
 
-    async fn cleanup_lists(&mut self, list_paths: Vec<PathBuf>) {
+    async fn cleanup_lists(&mut self, list_paths: Vec<Utf8PathBuf>) {
         for list_path in list_paths {
-            debug!("Removing deletion list {}", list_path.display());
+            debug!("Removing deletion list {list_path}");
 
             if let Err(e) = tokio::fs::remove_file(&list_path).await {
                 // Unexpected: we should have permissions and nothing else should
                 // be touching these files.  We will leave the file behind.  Subsequent
                 // pageservers will try and load it again: hopefully whatever storage
                 // issue (probably permissions) has been fixed by then.
-                tracing::error!("Failed to delete {}: {e:#}", list_path.display());
+                tracing::error!("Failed to delete {list_path}: {e:#}");
                 metrics::DELETION_QUEUE.unexpected_errors.inc();
                 break;
             }

pageserver/src/disk_usage_eviction_task.rs

@@ -43,12 +43,12 @@
 
 use std::{
     collections::HashMap,
-    path::Path,
     sync::Arc,
     time::{Duration, SystemTime},
 };
 
 use anyhow::Context;
+use camino::Utf8Path;
 use remote_storage::GenericRemoteStorage;
 use serde::{Deserialize, Serialize};
 use tokio::time::Instant;
@@ -122,7 +122,7 @@ async fn disk_usage_eviction_task(
     state: &State,
     task_config: &DiskUsageEvictionTaskConfig,
     storage: GenericRemoteStorage,
-    tenants_dir: &Path,
+    tenants_dir: &Utf8Path,
     cancel: CancellationToken,
 ) {
     scopeguard::defer! {
@@ -184,7 +184,7 @@ async fn disk_usage_eviction_task_iteration(
     state: &State,
     task_config: &DiskUsageEvictionTaskConfig,
     storage: &GenericRemoteStorage,
-    tenants_dir: &Path,
+    tenants_dir: &Utf8Path,
     cancel: &CancellationToken,
 ) -> anyhow::Result<()> {
     let usage_pre = filesystem_level_usage::get(tenants_dir, task_config)
@@ -620,9 +620,8 @@ impl std::ops::Deref for TimelineKey {
 }
 
 mod filesystem_level_usage {
-    use std::path::Path;
-
     use anyhow::Context;
+    use camino::Utf8Path;
 
     use crate::statvfs::Statvfs;
 
@@ -664,7 +663,7 @@ mod filesystem_level_usage {
     }
 
     pub fn get<'a>(
-        tenants_dir: &Path,
+        tenants_dir: &Utf8Path,
         config: &'a DiskUsageEvictionTaskConfig,
     ) -> anyhow::Result<Usage<'a>> {
         let mock_config = {

pageserver/src/http/routes.rs

@@ -10,7 +10,8 @@ use hyper::StatusCode;
 use hyper::{Body, Request, Response, Uri};
 use metrics::launch_timestamp::LaunchTimestamp;
 use pageserver_api::models::{
-    DownloadRemoteLayersTaskSpawnRequest, TenantAttachRequest, TenantLoadRequest,
+    DownloadRemoteLayersTaskSpawnRequest, LocationConfigMode, TenantAttachRequest,
+    TenantLoadRequest, TenantLocationConfigRequest,
 };
 use remote_storage::GenericRemoteStorage;
 use tenant_size_model::{SizeResult, StorageModel};
@@ -29,7 +30,7 @@ use crate::deletion_queue::DeletionQueueClient;
 use crate::metrics::{StorageTimeOperation, STORAGE_TIME_GLOBAL};
 use crate::pgdatadir_mapping::LsnForTimestamp;
 use crate::task_mgr::TaskKind;
-use crate::tenant::config::TenantConfOpt;
+use crate::tenant::config::{LocationConf, TenantConfOpt};
 use crate::tenant::mgr::{
     GetTenantError, SetNewTenantConfigError, TenantMapInsertError, TenantStateError,
 };
@@ -132,7 +133,7 @@ impl From<PageReconstructError> for ApiError {
                 ApiError::InternalServerError(anyhow::anyhow!("request was cancelled"))
             }
             PageReconstructError::AncestorStopping(_) => {
-                ApiError::InternalServerError(anyhow::Error::new(pre))
+                ApiError::ResourceUnavailable(format!("{pre}"))
             }
             PageReconstructError::WalRedo(pre) => {
                 ApiError::InternalServerError(anyhow::Error::new(pre))
@@ -145,12 +146,15 @@ impl From<TenantMapInsertError> for ApiError {
     fn from(tmie: TenantMapInsertError) -> ApiError {
         match tmie {
             TenantMapInsertError::StillInitializing | TenantMapInsertError::ShuttingDown => {
-                ApiError::InternalServerError(anyhow::Error::new(tmie))
+                ApiError::ResourceUnavailable(format!("{tmie}"))
             }
             TenantMapInsertError::TenantAlreadyExists(id, state) => {
                 ApiError::Conflict(format!("tenant {id} already exists, state: {state:?}"))
             }
-            TenantMapInsertError::Closure(e) => ApiError::InternalServerError(e),
+            TenantMapInsertError::TenantExistsSecondary(id) => {
+                ApiError::Conflict(format!("tenant {id} already exists as secondary"))
+            }
+            TenantMapInsertError::Other(e) => ApiError::InternalServerError(e),
         }
     }
 }
@@ -159,6 +163,12 @@ impl From<TenantStateError> for ApiError {
     fn from(tse: TenantStateError) -> ApiError {
         match tse {
             TenantStateError::NotFound(tid) => ApiError::NotFound(anyhow!("tenant {}", tid).into()),
+            TenantStateError::NotActive(_) => {
+                ApiError::ResourceUnavailable("Tenant not yet active".into())
+            }
+            TenantStateError::IsStopping(_) => {
+                ApiError::ResourceUnavailable("Tenant is stopping".into())
+            }
             _ => ApiError::InternalServerError(anyhow::Error::new(tse)),
         }
     }
@@ -168,14 +178,17 @@ impl From<GetTenantError> for ApiError {
     fn from(tse: GetTenantError) -> ApiError {
         match tse {
             GetTenantError::NotFound(tid) => ApiError::NotFound(anyhow!("tenant {}", tid).into()),
-            e @ GetTenantError::NotActive(_) => {
+            GetTenantError::Broken(reason) => {
+                ApiError::InternalServerError(anyhow!("tenant is broken: {}", reason))
+            }
+            GetTenantError::NotActive(_) => {
                 // Why is this not `ApiError::NotFound`?
                 // Because we must be careful to never return 404 for a tenant if it does
                 // in fact exist locally. If we did, the caller could draw the conclusion
                 // that it can attach the tenant to another PS and we'd be in split-brain.
                 //
                 // (We can produce this variant only in `mgr::get_tenant(..., active=true)` calls).
-                ApiError::InternalServerError(anyhow::Error::new(e))
+                ApiError::ResourceUnavailable("Tenant not yet active".into())
             }
         }
     }
@@ -622,8 +635,9 @@ async fn tenant_list_handler(
     let response_data = mgr::list_tenants()
         .instrument(info_span!("tenant_list"))
         .await
-        .map_err(anyhow::Error::new)
-        .map_err(ApiError::InternalServerError)?
+        .map_err(|_| {
+            ApiError::ResourceUnavailable("Tenant map is initializing or shutting down".to_string())
+        })?
         .iter()
         .map(|(id, state)| TenantInfo {
             id: *id,
@@ -1001,6 +1015,48 @@ async fn update_tenant_config_handler(
     json_response(StatusCode::OK, ())
 }
 
+async fn put_tenant_location_config_handler(
+    mut request: Request<Body>,
+    _cancel: CancellationToken,
+) -> Result<Response<Body>, ApiError> {
+    let request_data: TenantLocationConfigRequest = json_request(&mut request).await?;
+    let tenant_id = request_data.tenant_id;
+    check_permission(&request, Some(tenant_id))?;
+
+    let ctx = RequestContext::new(TaskKind::MgmtRequest, DownloadBehavior::Warn);
+    let state = get_state(&request);
+    let conf = state.conf;
+
+    // The `Detached` state is special, it doesn't upsert a tenant, it removes
+    // its local disk content and drops it from memory.
+    if let LocationConfigMode::Detached = request_data.config.mode {
+        mgr::detach_tenant(conf, tenant_id, true)
+            .instrument(info_span!("tenant_detach", %tenant_id))
+            .await?;
+        return json_response(StatusCode::OK, ());
+    }
+
+    let location_conf =
+        LocationConf::try_from(&request_data.config).map_err(ApiError::BadRequest)?;
+
+    mgr::upsert_location(
+        state.conf,
+        tenant_id,
+        location_conf,
+        state.broker_client.clone(),
+        state.remote_storage.clone(),
+        state.deletion_queue_client.clone(),
+        &ctx,
+    )
+    .await
+    // TODO: badrequest assumes the caller was asking for something unreasonable, but in
+    // principle we might have hit something like concurrent API calls to the same tenant,
+    // which is not a 400 but a 409.
+    .map_err(ApiError::BadRequest)?;
+
+    json_response(StatusCode::OK, ())
+}
+
 /// Testing helper to transition a tenant to [`crate::tenant::TenantState::Broken`].
 async fn handle_tenant_break(
     r: Request<Body>,
@@ -1454,6 +1510,9 @@ pub fn make_router(
         .get("/v1/tenant/:tenant_id/config", |r| {
             api_handler(r, get_tenant_config_handler)
         })
+        .put("/v1/tenant/:tenant_id/location_config", |r| {
+            api_handler(r, put_tenant_location_config_handler)
+        })
         .get("/v1/tenant/:tenant_id/timeline", |r| {
             api_handler(r, timeline_list_handler)
         })

pageserver/src/import_datadir.rs

@@ -6,6 +6,7 @@ use std::path::{Path, PathBuf};
 
 use anyhow::{bail, ensure, Context, Result};
 use bytes::Bytes;
+use camino::Utf8Path;
 use futures::StreamExt;
 use tokio::io::{AsyncRead, AsyncReadExt};
 use tokio_tar::Archive;
@@ -29,7 +30,7 @@ use postgres_ffi::{BLCKSZ, WAL_SEGMENT_SIZE};
 use utils::lsn::Lsn;
 
 // Returns checkpoint LSN from controlfile
-pub fn get_lsn_from_controlfile(path: &Path) -> Result<Lsn> {
+pub fn get_lsn_from_controlfile(path: &Utf8Path) -> Result<Lsn> {
     // Read control file to extract the LSN
     let controlfile_path = path.join("global").join("pg_control");
     let controlfile = ControlFileData::decode(&std::fs::read(controlfile_path)?)?;
@@ -46,7 +47,7 @@ pub fn get_lsn_from_controlfile(path: &Path) -> Result<Lsn> {
 /// cluster was not shut down cleanly.
 pub async fn import_timeline_from_postgres_datadir(
     tline: &Timeline,
-    pgdata_path: &Path,
+    pgdata_path: &Utf8Path,
     pgdata_lsn: Lsn,
     ctx: &RequestContext,
 ) -> Result<()> {
@@ -256,7 +257,7 @@ async fn import_slru(
 /// Scan PostgreSQL WAL files in given directory and load all records between
 /// 'startpoint' and 'endpoint' into the repository.
 async fn import_wal(
-    walpath: &Path,
+    walpath: &Utf8Path,
     tline: &Timeline,
     startpoint: Lsn,
     endpoint: Lsn,

pageserver/src/lib.rs

@@ -25,9 +25,8 @@ pub mod walredo;
 
 pub mod failpoint_support;
 
-use std::path::Path;
-
 use crate::task_mgr::TaskKind;
+use camino::Utf8Path;
 use deletion_queue::DeletionQueue;
 use tracing::info;
 
@@ -113,6 +112,10 @@ pub const METADATA_FILE_NAME: &str = "metadata";
 /// Full path: `tenants/<tenant_id>/config`.
 pub const TENANT_CONFIG_NAME: &str = "config";
 
+/// Per-tenant configuration file.
+/// Full path: `tenants/<tenant_id>/config`.
+pub const TENANT_LOCATION_CONFIG_NAME: &str = "config-v1";
+
 /// A suffix used for various temporary files. Any temporary files found in the
 /// data directory at pageserver startup can be automatically removed.
 pub const TEMP_FILE_SUFFIX: &str = "___temp";
@@ -132,25 +135,25 @@ pub const TIMELINE_DELETE_MARK_SUFFIX: &str = "___delete";
 /// Full path: `tenants/<tenant_id>/___ignored_tenant`.
 pub const IGNORED_TENANT_FILE_NAME: &str = "___ignored_tenant";
 
-pub fn is_temporary(path: &Path) -> bool {
+pub fn is_temporary(path: &Utf8Path) -> bool {
     match path.file_name() {
-        Some(name) => name.to_string_lossy().ends_with(TEMP_FILE_SUFFIX),
+        Some(name) => name.ends_with(TEMP_FILE_SUFFIX),
         None => false,
     }
 }
 
-fn ends_with_suffix(path: &Path, suffix: &str) -> bool {
+fn ends_with_suffix(path: &Utf8Path, suffix: &str) -> bool {
     match path.file_name() {
-        Some(name) => name.to_string_lossy().ends_with(suffix),
+        Some(name) => name.ends_with(suffix),
         None => false,
     }
 }
 
-pub fn is_uninit_mark(path: &Path) -> bool {
+pub fn is_uninit_mark(path: &Utf8Path) -> bool {
     ends_with_suffix(path, TIMELINE_UNINIT_MARK_SUFFIX)
 }
 
-pub fn is_delete_mark(path: &Path) -> bool {
+pub fn is_delete_mark(path: &Utf8Path) -> bool {
     ends_with_suffix(path, TIMELINE_DELETE_MARK_SUFFIX)
 }
 

pageserver/src/metrics.rs

@@ -94,15 +94,35 @@ pub(crate) static READ_NUM_FS_LAYERS: Lazy<Histogram> = Lazy::new(|| {
 });
 
 // Metrics collected on operations on the storage repository.
-pub(crate) static RECONSTRUCT_TIME: Lazy<Histogram> = Lazy::new(|| {
-    register_histogram!(
+
+pub(crate) struct ReconstructTimeMetrics {
+    ok: Histogram,
+    err: Histogram,
+}
+
+pub(crate) static RECONSTRUCT_TIME: Lazy<ReconstructTimeMetrics> = Lazy::new(|| {
+    let inner = register_histogram_vec!(
         "pageserver_getpage_reconstruct_seconds",
         "Time spent in reconstruct_value (reconstruct a page from deltas)",
+        &["result"],
         CRITICAL_OP_BUCKETS.into(),
     )
-    .expect("failed to define a metric")
+    .expect("failed to define a metric");
+    ReconstructTimeMetrics {
+        ok: inner.get_metric_with_label_values(&["ok"]).unwrap(),
+        err: inner.get_metric_with_label_values(&["err"]).unwrap(),
+    }
 });
 
+impl ReconstructTimeMetrics {
+    pub(crate) fn for_result<T, E>(&self, result: &Result<T, E>) -> &Histogram {
+        match result {
+            Ok(_) => &self.ok,
+            Err(_) => &self.err,
+        }
+    }
+}
+
 pub(crate) static MATERIALIZED_PAGE_CACHE_HIT_DIRECT: Lazy<IntCounter> = Lazy::new(|| {
     register_int_counter!(
         "pageserver_materialized_cache_hits_direct_total",
@@ -294,7 +314,6 @@ static PAGE_CACHE_ERRORS: Lazy<IntCounterVec> = Lazy::new(|| {
 #[strum(serialize_all = "kebab_case")]
 pub(crate) enum PageCacheErrorKind {
     AcquirePinnedSlotTimeout,
-    EvictIterLimit,
 }
 
 pub(crate) fn page_cache_errors_inc(error_kind: PageCacheErrorKind) {
@@ -1856,7 +1875,6 @@ pub fn preinitialize_metrics() {
     // histograms
     [
         &READ_NUM_FS_LAYERS,
-        &RECONSTRUCT_TIME,
         &WAIT_LSN_TIME,
         &WAL_REDO_TIME,
         &WAL_REDO_WAIT_TIME,
@@ -1867,4 +1885,7 @@ pub fn preinitialize_metrics() {
     .for_each(|h| {
         Lazy::force(h);
     });
+
+    // Custom
+    Lazy::force(&RECONSTRUCT_TIME);
 }

pageserver/src/page_cache.rs

@@ -66,8 +66,7 @@
 //! inserted to the mapping, but you must hold the write-lock on the slot until
 //! the contents are valid. If you need to release the lock without initializing
 //! the contents, you must remove the mapping first. We make that easy for the
-//! callers with PageWriteGuard: when lock_for_write() returns an uninitialized
-//! page, the caller must explicitly call guard.mark_valid() after it has
+//! callers with PageWriteGuard: the caller must explicitly call guard.mark_valid() after it has
 //! initialized it. If the guard is dropped without calling mark_valid(), the
 //! mapping is automatically removed and the slot is marked free.
 //!
@@ -79,6 +78,7 @@ use std::{
         atomic::{AtomicU64, AtomicU8, AtomicUsize, Ordering},
         Arc, Weak,
     },
+    task::Poll,
     time::Duration,
 };
 
@@ -215,16 +215,21 @@ impl Slot {
 
 impl SlotInner {
     /// If there is aready a reader, drop our permit and share its permit, just like we share read access.
-    fn coalesce_readers_permit(&self, permit: PinnedSlotsPermit) -> Arc<PinnedSlotsPermit> {
-        let mut guard = self.permit.lock().unwrap();
-        if let Some(existing_permit) = guard.upgrade() {
-            drop(guard);
-            drop(permit);
-            existing_permit
-        } else {
-            let permit = Arc::new(permit);
-            *guard = Arc::downgrade(&permit);
-            permit
+    fn coalesce_readers_permit<'c>(&self, permit: PermitKind<'c>) -> PermitKindReadGuard<'c> {
+        match permit {
+            PermitKind::CtxProvided(permit) => PermitKindReadGuard::CtxProvided(permit),
+            PermitKind::Acquired(permit) => {
+                let mut guard = self.permit.lock().unwrap();
+                if let Some(existing_permit) = guard.upgrade() {
+                    drop(guard);
+                    drop(permit);
+                    existing_permit
+                } else {
+                    let permit = Arc::new(permit);
+                    *guard = Arc::downgrade(&permit);
+                    permit
+                }
+            }
         }
     }
 }
@@ -252,21 +257,36 @@ pub struct PageCache {
     /// This is interpreted modulo the page cache size.
     next_evict_slot: AtomicUsize,
 
+    find_victim_sender:
+        async_channel::Sender<(usize, tokio::sync::RwLockWriteGuard<'static, SlotInner>)>,
+    find_victim_waiters:
+        async_channel::Receiver<(usize, tokio::sync::RwLockWriteGuard<'static, SlotInner>)>,
+
     size_metrics: &'static PageCacheSizeMetrics,
 }
 
-struct PinnedSlotsPermit(tokio::sync::OwnedSemaphorePermit);
+pub(crate) struct PinnedSlotsPermit(tokio::sync::OwnedSemaphorePermit);
+
+enum PermitKind<'c> {
+    CtxProvided(&'c PinnedSlotsPermit),
+    Acquired(PinnedSlotsPermit),
+}
+
+enum PermitKindReadGuard<'c> {
+    CtxProvided(&'c PinnedSlotsPermit),
+    Coalesced(Arc<PinnedSlotsPermit>),
+}
 
 ///
 /// PageReadGuard is a "lease" on a buffer, for reading. The page is kept locked
 /// until the guard is dropped.
 ///
-pub struct PageReadGuard<'i> {
-    _permit: Arc<PinnedSlotsPermit>,
+pub struct PageReadGuard<'c, 'i> {
+    _permit: PermitKindReadGuard<'c>,
     slot_guard: tokio::sync::RwLockReadGuard<'i, SlotInner>,
 }
 
-impl std::ops::Deref for PageReadGuard<'_> {
+impl std::ops::Deref for PageReadGuard<'_, '_> {
     type Target = [u8; PAGE_SZ];
 
     fn deref(&self) -> &Self::Target {
@@ -274,7 +294,7 @@ impl std::ops::Deref for PageReadGuard<'_> {
     }
 }
 
-impl AsRef<[u8; PAGE_SZ]> for PageReadGuard<'_> {
+impl AsRef<[u8; PAGE_SZ]> for PageReadGuard<'_, '_> {
     fn as_ref(&self) -> &[u8; PAGE_SZ] {
         self.slot_guard.buf
     }
@@ -286,78 +306,89 @@ impl AsRef<[u8; PAGE_SZ]> for PageReadGuard<'_> {
 ///
 /// Counterintuitively, this is used even for a read, if the requested page is not
 /// currently found in the page cache. In that case, the caller of lock_for_read()
-/// is expected to fill in the page contents and call mark_valid(). Similarly
-/// lock_for_write() can return an invalid buffer that the caller is expected to
-/// to initialize.
-///
-pub struct PageWriteGuard<'i> {
-    inner: tokio::sync::RwLockWriteGuard<'i, SlotInner>,
-
-    _permit: PinnedSlotsPermit,
-
-    // Are the page contents currently valid?
-    // Used to mark pages as invalid that are assigned but not yet filled with data.
-    valid: bool,
+/// is expected to fill in the page contents and call mark_valid().
+pub struct PageWriteGuard<'c, 'i> {
+    state: PageWriteGuardState<'c, 'i>,
 }
 
-impl std::ops::DerefMut for PageWriteGuard<'_> {
+enum PageWriteGuardState<'c, 'i> {
+    Invalid {
+        inner: tokio::sync::RwLockWriteGuard<'i, SlotInner>,
+        _permit: PermitKindReadGuard<'c>,
+    },
+    Downgraded,
+}
+
+impl std::ops::DerefMut for PageWriteGuard<'_, '_> {
     fn deref_mut(&mut self) -> &mut Self::Target {
-        self.inner.buf
+        match &mut self.state {
+            PageWriteGuardState::Invalid { inner, _permit } => inner.buf,
+            PageWriteGuardState::Downgraded => unreachable!(),
+        }
     }
 }
 
-impl std::ops::Deref for PageWriteGuard<'_> {
+impl std::ops::Deref for PageWriteGuard<'_, '_> {
     type Target = [u8; PAGE_SZ];
 
     fn deref(&self) -> &Self::Target {
-        self.inner.buf
+        match &self.state {
+            PageWriteGuardState::Invalid { inner, _permit } => inner.buf,
+            PageWriteGuardState::Downgraded => unreachable!(),
+        }
     }
 }
 
-impl AsMut<[u8; PAGE_SZ]> for PageWriteGuard<'_> {
+impl AsMut<[u8; PAGE_SZ]> for PageWriteGuard<'_, '_> {
     fn as_mut(&mut self) -> &mut [u8; PAGE_SZ] {
-        self.inner.buf
+        match &mut self.state {
+            PageWriteGuardState::Invalid { inner, _permit } => inner.buf,
+            PageWriteGuardState::Downgraded => todo!(),
+        }
     }
 }
 
-impl PageWriteGuard<'_> {
+impl<'c, 'a> PageWriteGuard<'c, 'a> {
     /// Mark that the buffer contents are now valid.
-    pub fn mark_valid(&mut self) {
-        assert!(self.inner.key.is_some());
-        assert!(
-            !self.valid,
-            "mark_valid called on a buffer that was already valid"
-        );
-        self.valid = true;
+    #[must_use]
+    pub fn mark_valid(mut self) -> PageReadGuard<'c, 'a> {
+        let prev = std::mem::replace(&mut self.state, PageWriteGuardState::Downgraded);
+        match prev {
+            PageWriteGuardState::Invalid { inner, _permit } => {
+                assert!(inner.key.is_some());
+                PageReadGuard {
+                    _permit,
+                    slot_guard: inner.downgrade(),
+                }
+            }
+            PageWriteGuardState::Downgraded => unreachable!(),
+        }
     }
 }
 
-impl Drop for PageWriteGuard<'_> {
+impl Drop for PageWriteGuard<'_, '_> {
     ///
     /// If the buffer was allocated for a page that was not already in the
     /// cache, but the lock_for_read/write() caller dropped the buffer without
     /// initializing it, remove the mapping from the page cache.
     ///
     fn drop(&mut self) {
-        assert!(self.inner.key.is_some());
-        if !self.valid {
-            let self_key = self.inner.key.as_ref().unwrap();
-            PAGE_CACHE.get().unwrap().remove_mapping(self_key);
-            self.inner.key = None;
+        match &mut self.state {
+            PageWriteGuardState::Invalid { inner, _permit } => {
+                assert!(inner.key.is_some());
+                let self_key = inner.key.as_ref().unwrap();
+                PAGE_CACHE.get().unwrap().remove_mapping(self_key);
+                inner.key = None;
+            }
+            PageWriteGuardState::Downgraded => {}
         }
     }
 }
 
 /// lock_for_read() return value
-pub enum ReadBufResult<'a> {
-    Found(PageReadGuard<'a>),
-    NotFound(PageWriteGuard<'a>),
-}
-
-/// lock_for_write() return value
-pub enum WriteBufResult<'a> {
-    Found(PageWriteGuard<'a>),
-    NotFound(PageWriteGuard<'a>),
+pub enum ReadBufResult<'c, 'a> {
+    Found(PageReadGuard<'c, 'a>),
+    NotFound(PageWriteGuard<'c, 'a>),
 }
 
 impl PageCache {
@@ -379,10 +410,9 @@ impl PageCache {
         lsn: Lsn,
         ctx: &RequestContext,
     ) -> Option<(Lsn, PageReadGuard)> {
-        let Ok(permit) = self.try_get_pinned_slot_permit().await else {
+        let Ok(permit) = self.try_get_pinned_slot_permit(ctx).await else {
             return None;
         };
-
         crate::metrics::PAGE_CACHE
             .for_ctx(ctx)
             .read_accesses_materialized_page
@@ -430,12 +460,13 @@ impl PageCache {
     /// Store an image of the given page in the cache.
     ///
     pub async fn memorize_materialized_page(
-        &self,
+        &'static self,
         tenant_id: TenantId,
         timeline_id: TimelineId,
         key: Key,
         lsn: Lsn,
         img: &[u8],
+        ctx: &RequestContext,
     ) -> anyhow::Result<()> {
         let cache_key = CacheKey::MaterializedPage {
             hash_key: MaterializedPageHashKey {
@@ -446,30 +477,87 @@ impl PageCache {
             lsn,
         };
 
-        match self.lock_for_write(&cache_key).await? {
-            WriteBufResult::Found(write_guard) => {
-                // We already had it in cache. Another thread must've put it there
-                // concurrently. Check that it had the same contents that we
-                // replayed.
-                assert!(*write_guard == img);
+        let mut permit = Some(self.try_get_pinned_slot_permit(ctx).await?);
+        loop {
+            // First check if the key already exists in the cache.
+            if let Some(slot_idx) = self.search_mapping_exact(&cache_key) {
+                // The page was found in the mapping. Lock the slot, and re-check
+                // that it's still what we expected (because we don't released the mapping
+                // lock already, another thread could have evicted the page)
+                let slot = &self.slots[slot_idx];
+                let inner = slot.inner.write().await;
+                if inner.key.as_ref() == Some(&cache_key) {
+                    slot.inc_usage_count();
+                    debug_assert!(
+                        {
+                            let guard = inner.permit.lock().unwrap();
+                            guard.upgrade().is_none()
+                        },
+                        "we hold a write lock, so, no one else should have a permit"
+                    );
+                    debug_assert_eq!(inner.buf.len(), img.len());
+                    // We already had it in cache. Another thread must've put it there
+                    // concurrently. Check that it had the same contents that we
+                    // replayed.
+                    assert!(inner.buf == img);
+                    return Ok(());
+                }
             }
-            WriteBufResult::NotFound(mut write_guard) => {
-                write_guard.copy_from_slice(img);
-                write_guard.mark_valid();
-            }
-        }
+            debug_assert!(permit.is_some());
 
-        Ok(())
+            // Not found. Find a victim buffer
+            let (slot_idx, mut inner) = self
+                .find_victim(permit.as_ref().unwrap())
+                .await
+                .context("Failed to find evict victim")?;
+
+            // Insert mapping for this. At this point, we may find that another
+            // thread did the same thing concurrently. In that case, we evicted
+            // our victim buffer unnecessarily. Put it into the free list and
+            // continue with the slot that the other thread chose.
+            if let Some(_existing_slot_idx) = self.try_insert_mapping(&cache_key, slot_idx) {
+                // TODO: put to free list
+
+                // We now just loop back to start from beginning. This is not
+                // optimal, we'll perform the lookup in the mapping again, which
+                // is not really necessary because we already got
+                // 'existing_slot_idx'.  But this shouldn't happen often enough
+                // to matter much.
+                continue;
+            }
+
+            // Make the slot ready
+            let slot = &self.slots[slot_idx];
+            inner.key = Some(cache_key.clone());
+            slot.set_usage_count(1);
+            // Create a write guard for the slot so we go through the expected motions.
+            debug_assert!(
+                {
+                    let guard = inner.permit.lock().unwrap();
+                    guard.upgrade().is_none()
+                },
+                "we hold a write lock, so, no one else should have a permit"
+            );
+            let mut write_guard = PageWriteGuard {
+                state: PageWriteGuardState::Invalid {
+                    _permit: permit.take().unwrap(),
+                    inner,
+                },
+            };
+            write_guard.copy_from_slice(img);
+            let _ = write_guard.mark_valid();
+            return Ok(());
+        }
     }
 
     // Section 1.2: Public interface functions for working with immutable file pages.
 
-    pub async fn read_immutable_buf(
-        &self,
+    pub async fn read_immutable_buf<'c>(
+        &'static self,
         file_id: FileId,
         blkno: u32,
-        ctx: &RequestContext,
-    ) -> anyhow::Result<ReadBufResult> {
+        ctx: &'c RequestContext,
+    ) -> anyhow::Result<ReadBufResult<'c, 'static>> {
         let mut cache_key = CacheKey::ImmutableFilePage { file_id, blkno };
 
         self.lock_for_read(&mut cache_key, ctx).await
@@ -483,7 +571,22 @@ impl PageCache {
     // "mappings" after this section. But the routines in this section should
     // not require changes.
 
-    async fn try_get_pinned_slot_permit(&self) -> anyhow::Result<PinnedSlotsPermit> {
+    pub(crate) async fn get_permit(&self) -> Arc<PinnedSlotsPermit> {
+        Arc::new(PinnedSlotsPermit(
+            Arc::clone(&self.pinned_slots)
+                .acquire_owned()
+                .await
+                .expect("the semaphore is never closed"),
+        ))
+    }
+
+    async fn try_get_pinned_slot_permit<'c>(
+        &self,
+        ctx: &'c RequestContext,
+    ) -> anyhow::Result<PermitKind<'c>> {
+        if let Some(permit) = ctx.permit() {
+            return Ok(PermitKind::CtxProvided(permit));
+        };
         let timer = crate::metrics::PAGE_CACHE_ACQUIRE_PINNED_SLOT_TIME.start_timer();
         match tokio::time::timeout(
             // Choose small timeout, neon_smgr does its own retries.
@@ -493,9 +596,9 @@ impl PageCache {
         )
         .await
         {
-            Ok(res) => Ok(PinnedSlotsPermit(
+            Ok(res) => Ok(PermitKind::Acquired(PinnedSlotsPermit(
                 res.expect("this semaphore is never closed"),
-            )),
+            ))),
             Err(_timeout) => {
                 timer.stop_and_discard();
                 crate::metrics::page_cache_errors_inc(
@@ -515,10 +618,10 @@ impl PageCache {
     ///
     /// If no page is found, returns None and *cache_key is left unmodified.
     ///
-    async fn try_lock_for_read(
+    async fn try_lock_for_read<'c>(
         &self,
         cache_key: &mut CacheKey,
-        permit: &mut Option<PinnedSlotsPermit>,
+        permit: &mut Option<PermitKind<'c>>,
     ) -> Option<PageReadGuard> {
         let cache_key_orig = cache_key.clone();
         if let Some(slot_idx) = self.search_mapping(cache_key) {
@@ -571,11 +674,11 @@ impl PageCache {
     /// ```
     ///
     async fn lock_for_read(
-        &self,
+        &'static self,
         cache_key: &mut CacheKey,
         ctx: &RequestContext,
     ) -> anyhow::Result<ReadBufResult> {
-        let mut permit = Some(self.try_get_pinned_slot_permit().await?);
+        let mut permit = Some(self.try_get_pinned_slot_permit(ctx).await?);
 
         let (read_access, hit) = match cache_key {
             CacheKey::MaterializedPage { .. } => {
@@ -638,99 +741,10 @@ impl PageCache {
             );
 
             return Ok(ReadBufResult::NotFound(PageWriteGuard {
-                _permit: permit.take().unwrap(),
-                inner,
-                valid: false,
-            }));
-        }
-    }
-
-    /// Look up a page in the cache and lock it in write mode. If it's not
-    /// found, returns None.
-    ///
-    /// When locking a page for writing, the search criteria is always "exact".
-    async fn try_lock_for_write(
-        &self,
-        cache_key: &CacheKey,
-        permit: &mut Option<PinnedSlotsPermit>,
-    ) -> Option<PageWriteGuard> {
-        if let Some(slot_idx) = self.search_mapping_for_write(cache_key) {
-            // The page was found in the mapping. Lock the slot, and re-check
-            // that it's still what we expected (because we don't released the mapping
-            // lock already, another thread could have evicted the page)
-            let slot = &self.slots[slot_idx];
-            let inner = slot.inner.write().await;
-            if inner.key.as_ref() == Some(cache_key) {
-                slot.inc_usage_count();
-                debug_assert!(
-                    {
-                        let guard = inner.permit.lock().unwrap();
-                        guard.upgrade().is_none()
-                    },
-                    "we hold a write lock, so, no one else should have a permit"
-                );
-                return Some(PageWriteGuard {
+                state: PageWriteGuardState::Invalid {
                     _permit: permit.take().unwrap(),
                     inner,
-                    valid: true,
-                });
-            }
-        }
-        None
-    }
-
-    /// Return a write-locked buffer for given block.
-    ///
-    /// Similar to lock_for_read(), but the returned buffer is write-locked and
-    /// may be modified by the caller even if it's already found in the cache.
-    async fn lock_for_write(&self, cache_key: &CacheKey) -> anyhow::Result<WriteBufResult> {
-        let mut permit = Some(self.try_get_pinned_slot_permit().await?);
-        loop {
-            // First check if the key already exists in the cache.
-            if let Some(write_guard) = self.try_lock_for_write(cache_key, &mut permit).await {
-                debug_assert!(permit.is_none());
-                return Ok(WriteBufResult::Found(write_guard));
-            }
-            debug_assert!(permit.is_some());
-
-            // Not found. Find a victim buffer
-            let (slot_idx, mut inner) = self
-                .find_victim(permit.as_ref().unwrap())
-                .await
-                .context("Failed to find evict victim")?;
-
-            // Insert mapping for this. At this point, we may find that another
-            // thread did the same thing concurrently. In that case, we evicted
-            // our victim buffer unnecessarily. Put it into the free list and
-            // continue with the slot that the other thread chose.
-            if let Some(_existing_slot_idx) = self.try_insert_mapping(cache_key, slot_idx) {
-                // TODO: put to free list
-
-                // We now just loop back to start from beginning. This is not
-                // optimal, we'll perform the lookup in the mapping again, which
-                // is not really necessary because we already got
-                // 'existing_slot_idx'.  But this shouldn't happen often enough
-                // to matter much.
-                continue;
-            }
-
-            // Make the slot ready
-            let slot = &self.slots[slot_idx];
-            inner.key = Some(cache_key.clone());
-            slot.set_usage_count(1);
-
-            debug_assert!(
-                {
-                    let guard = inner.permit.lock().unwrap();
-                    guard.upgrade().is_none()
                 },
-                "we hold a write lock, so, no one else should have a permit"
-            );
-
-            return Ok(WriteBufResult::NotFound(PageWriteGuard {
-                _permit: permit.take().unwrap(),
-                inner,
-                valid: false,
             }));
         }
     }
@@ -775,7 +789,7 @@ impl PageCache {
     ///
     /// Like 'search_mapping, but performs an "exact" search. Used for
     /// allocating a new buffer.
-    fn search_mapping_for_write(&self, key: &CacheKey) -> Option<usize> {
+    fn search_mapping_exact(&self, key: &CacheKey) -> Option<usize> {
         match key {
             CacheKey::MaterializedPage { hash_key, lsn } => {
                 let map = self.materialized_page_map.read().unwrap();
@@ -882,10 +896,12 @@ impl PageCache {
     ///
     /// On return, the slot is empty and write-locked.
     async fn find_victim(
-        &self,
+        &'static self,
         _permit_witness: &PinnedSlotsPermit,
     ) -> anyhow::Result<(usize, tokio::sync::RwLockWriteGuard<SlotInner>)> {
-        let iter_limit = self.slots.len() * 10;
+        // Get in line.
+        let receiver = self.find_victim_waiters.recv();
+
         let mut iters = 0;
         loop {
             iters += 1;
@@ -897,41 +913,8 @@ impl PageCache {
                 let mut inner = match slot.inner.try_write() {
                     Ok(inner) => inner,
                     Err(_err) => {
-                        if iters > iter_limit {
-                            // NB: Even with the permits, there's no hard guarantee that we will find a slot with
-                            // any particular number of iterations: other threads might race ahead and acquire and
-                            // release pins just as we're scanning the array.
-                            //
-                            // Imagine that nslots is 2, and as starting point, usage_count==1 on all
-                            // slots. There are two threads running concurrently, A and B. A has just
-                            // acquired the permit from the semaphore.
-                            //
-                            //   A: Look at slot 1. Its usage_count == 1, so decrement it to zero, and continue the search
-                            //   B: Acquire permit.
-                            //   B: Look at slot 2, decrement its usage_count to zero and continue the search
-                            //   B: Look at slot 1. Its usage_count is zero, so pin it and bump up its usage_count to 1.
-                            //   B: Release pin and permit again
-                            //   B: Acquire permit.
-                            //   B: Look at slot 2. Its usage_count is zero, so pin it and bump up its usage_count to 1.
-                            //   B: Release pin and permit again
-                            //
-                            // Now we're back in the starting situation that both slots have
-                            // usage_count 1, but A has now been through one iteration of the
-                            // find_victim() loop. This can repeat indefinitely and on each
-                            // iteration, A's iteration count increases by one.
-                            //
-                            // So, even though the semaphore for the permits is fair, the victim search
-                            // itself happens in parallel and is not fair.
-                            // Hence even with a permit, a task can theoretically be starved.
-                            // To avoid this, we'd need tokio to give priority to tasks that are holding
-                            // permits for longer.
-                            // Note that just yielding to tokio during iteration without such
-                            // priority boosting is likely counter-productive. We'd just give more opportunities
-                            // for B to bump usage count, further starving A.
-                            crate::metrics::page_cache_errors_inc(
-                                crate::metrics::PageCacheErrorKind::EvictIterLimit,
-                            );
-                            anyhow::bail!("exceeded evict iter limit");
+                        if iters > self.slots.len() * (MAX_USAGE_COUNT as usize) {
+                            unreachable!("find_victim_waiters prevents starvation");
                         }
                         continue;
                     }
@@ -942,7 +925,16 @@ impl PageCache {
                     inner.key = None;
                 }
                 crate::metrics::PAGE_CACHE_FIND_VICTIMS_ITERS_TOTAL.inc_by(iters as u64);
-                return Ok((slot_idx, inner));
+                self.find_victim_sender
+                    .try_send((slot_idx, inner))
+                    .expect("we always get in line first");
+                match futures::poll!(receiver) {
+                    Poll::Ready(Ok(res)) => return Ok(res),
+                    Poll::Ready(Err(_closed)) => unreachable!("we never close"),
+                    Poll::Pending => {
+                        unreachable!("we just sent to the channel and got in line earlier")
+                    }
+                }
             }
         }
     }
@@ -979,6 +971,7 @@ impl PageCache {
             })
             .collect();
 
+        let (find_victim_sender, find_victim_waiters) = async_channel::bounded(num_pages);
         Self {
             materialized_page_map: Default::default(),
             immutable_page_map: Default::default(),
@@ -986,6 +979,8 @@ impl PageCache {
             next_evict_slot: AtomicUsize::new(0),
             size_metrics,
             pinned_slots: Arc::new(tokio::sync::Semaphore::new(num_pages)),
+            find_victim_sender,
+            find_victim_waiters,
         }
     }
 }

pageserver/src/page_service.rs

@@ -412,31 +412,53 @@ impl PageServerHandler {
             // TODO: We could create a new per-request context here, with unique ID.
             // Currently we use the same per-timeline context for all requests
 
-            let response = match neon_fe_msg {
+            let (response, span) = match neon_fe_msg {
                 PagestreamFeMessage::Exists(req) => {
                     let _timer = metrics.start_timer(metrics::SmgrQueryType::GetRelExists);
-                    self.handle_get_rel_exists_request(&timeline, &req, &ctx)
-                        .await
+                    let span = tracing::info_span!("handle_get_rel_exists_request", rel = %req.rel, req_lsn = %req.lsn);
+                    (
+                        self.handle_get_rel_exists_request(&timeline, &req, &ctx)
+                            .instrument(span.clone())
+                            .await,
+                        span,
+                    )
                 }
                 PagestreamFeMessage::Nblocks(req) => {
                     let _timer = metrics.start_timer(metrics::SmgrQueryType::GetRelSize);
-                    self.handle_get_nblocks_request(&timeline, &req, &ctx).await
+                    let span = tracing::info_span!("handle_get_nblocks_request", rel = %req.rel, req_lsn = %req.lsn);
+                    (
+                        self.handle_get_nblocks_request(&timeline, &req, &ctx)
+                            .instrument(span.clone())
+                            .await,
+                        span,
+                    )
                 }
                 PagestreamFeMessage::GetPage(req) => {
                     let _timer = metrics.start_timer(metrics::SmgrQueryType::GetPageAtLsn);
-                    self.handle_get_page_at_lsn_request(&timeline, &req, &ctx)
-                        .await
+                    let span = tracing::info_span!("handle_get_page_at_lsn_request", rel = %req.rel, blkno = %req.blkno, req_lsn = %req.lsn);
+                    (
+                        self.handle_get_page_at_lsn_request(&timeline, &req, &ctx)
+                            .instrument(span.clone())
+                            .await,
+                        span,
+                    )
                 }
                 PagestreamFeMessage::DbSize(req) => {
                     let _timer = metrics.start_timer(metrics::SmgrQueryType::GetDbSize);
-                    self.handle_db_size_request(&timeline, &req, &ctx).await
+                    let span = tracing::info_span!("handle_db_size_request", dbnode = %req.dbnode, req_lsn = %req.lsn);
+                    (
+                        self.handle_db_size_request(&timeline, &req, &ctx)
+                            .instrument(span.clone())
+                            .await,
+                        span,
+                    )
                 }
             };
 
             let response = response.unwrap_or_else(|e| {
                 // print the all details to the log with {:#}, but for the client the
                 // error message is enough
-                error!("error reading relation or page version: {:?}", e);
+                span.in_scope(|| error!("error reading relation or page version: {:#}", e));
                 PagestreamBeMessage::Error(PagestreamErrorResponse {
                     message: e.to_string(),
                 })
@@ -627,7 +649,6 @@ impl PageServerHandler {
         Ok(lsn)
     }
 
-    #[instrument(skip(self, timeline, req, ctx), fields(rel = %req.rel, req_lsn = %req.lsn))]
     async fn handle_get_rel_exists_request(
         &self,
         timeline: &Timeline,
@@ -648,7 +669,6 @@ impl PageServerHandler {
         }))
     }
 
-    #[instrument(skip(self, timeline, req, ctx), fields(rel = %req.rel, req_lsn = %req.lsn))]
     async fn handle_get_nblocks_request(
         &self,
         timeline: &Timeline,
@@ -667,7 +687,6 @@ impl PageServerHandler {
         }))
     }
 
-    #[instrument(skip(self, timeline, req, ctx), fields(dbnode = %req.dbnode, req_lsn = %req.lsn))]
     async fn handle_db_size_request(
         &self,
         timeline: &Timeline,
@@ -689,7 +708,6 @@ impl PageServerHandler {
         }))
     }
 
-    #[instrument(skip(self, timeline, req, ctx), fields(rel = %req.rel, blkno = %req.blkno, req_lsn = %req.lsn))]
     async fn handle_get_page_at_lsn_request(
         &self,
         timeline: &Timeline,
@@ -1265,7 +1283,10 @@ async fn get_active_tenant_with_timeout(
         Ok(tenant) => tenant,
         Err(e @ GetTenantError::NotFound(_)) => return Err(GetActiveTenantError::NotFound(e)),
         Err(GetTenantError::NotActive(_)) => {
-            unreachable!("we're calling get_tenant with active=false")
+            unreachable!("we're calling get_tenant with active_only=false")
+        }
+        Err(GetTenantError::Broken(_)) => {
+            unreachable!("we're calling get_tenant with active_only=false")
         }
     };
     let wait_time = Duration::from_secs(30);

pageserver/src/statvfs.rs

@@ -1,6 +1,6 @@
 //! Wrapper around nix::sys::statvfs::Statvfs that allows for mocking.
 
-use std::path::Path;
+use camino::Utf8Path;
 
 pub enum Statvfs {
     Real(nix::sys::statvfs::Statvfs),
@@ -12,11 +12,13 @@ pub enum Statvfs {
 // Sincce it should only be a problem on > 2TiB disks, let's ignore
 // the problem for now and upcast to u64.
 impl Statvfs {
-    pub fn get(tenants_dir: &Path, mocked: Option<&mock::Behavior>) -> nix::Result<Self> {
+    pub fn get(tenants_dir: &Utf8Path, mocked: Option<&mock::Behavior>) -> nix::Result<Self> {
         if let Some(mocked) = mocked {
             Ok(Statvfs::Mock(mock::get(tenants_dir, mocked)?))
         } else {
-            Ok(Statvfs::Real(nix::sys::statvfs::statvfs(tenants_dir)?))
+            Ok(Statvfs::Real(nix::sys::statvfs::statvfs(
+                tenants_dir.as_std_path(),
+            )?))
         }
     }
 
@@ -55,8 +57,8 @@ impl Statvfs {
 
 pub mod mock {
     use anyhow::Context;
+    use camino::Utf8Path;
     use regex::Regex;
-    use std::path::Path;
     use tracing::log::info;
 
     #[derive(Debug, Clone, PartialEq, Eq, serde::Serialize, serde::Deserialize)]
@@ -86,7 +88,7 @@ pub mod mock {
         }
     }
 
-    pub fn get(tenants_dir: &Path, behavior: &Behavior) -> nix::Result<Statvfs> {
+    pub fn get(tenants_dir: &Utf8Path, behavior: &Behavior) -> nix::Result<Statvfs> {
         info!("running mocked statvfs");
 
         match behavior {
@@ -119,7 +121,7 @@ pub mod mock {
         }
     }
 
-    fn walk_dir_disk_usage(path: &Path, name_filter: Option<&Regex>) -> anyhow::Result<u64> {
+    fn walk_dir_disk_usage(path: &Utf8Path, name_filter: Option<&Regex>) -> anyhow::Result<u64> {
         let mut total = 0;
         for entry in walkdir::WalkDir::new(path) {
             let entry = entry?;

pageserver/src/tenant.rs

@@ -12,6 +12,7 @@
 //!
 
 use anyhow::{bail, Context};
+use camino::{Utf8Path, Utf8PathBuf};
 use futures::FutureExt;
 use pageserver_api::models::TimelineState;
 use remote_storage::DownloadError;
@@ -34,8 +35,6 @@ use std::fs;
 use std::fs::File;
 use std::io;
 use std::ops::Bound::Included;
-use std::path::Path;
-use std::path::PathBuf;
 use std::process::Command;
 use std::process::Stdio;
 use std::sync::atomic::AtomicU64;
@@ -45,6 +44,8 @@ use std::sync::MutexGuard;
 use std::sync::{Mutex, RwLock};
 use std::time::{Duration, Instant};
 
+use self::config::AttachedLocationConfig;
+use self::config::LocationConf;
 use self::config::TenantConf;
 use self::delete::DeleteTenantFlow;
 use self::metadata::LoadMetadataError;
@@ -65,6 +66,7 @@ use crate::metrics::{remove_tenant_metrics, TENANT_STATE_METRIC, TENANT_SYNTHETI
 use crate::repository::GcResult;
 use crate::task_mgr;
 use crate::task_mgr::TaskKind;
+use crate::tenant::config::LocationMode;
 use crate::tenant::config::TenantConfOpt;
 use crate::tenant::metadata::load_metadata;
 pub use crate::tenant::remote_timeline_client::index::IndexPart;
@@ -161,6 +163,28 @@ pub struct TenantSharedResources {
     pub deletion_queue_client: DeletionQueueClient,
 }
 
+/// A [`Tenant`] is really an _attached_ tenant.  The configuration
+/// for an attached tenant is a subset of the [`LocationConf`], represented
+/// in this struct.
+pub(super) struct AttachedTenantConf {
+    tenant_conf: TenantConfOpt,
+    location: AttachedLocationConfig,
+}
+
+impl AttachedTenantConf {
+    fn try_from(location_conf: LocationConf) -> anyhow::Result<Self> {
+        match &location_conf.mode {
+            LocationMode::Attached(attach_conf) => Ok(Self {
+                tenant_conf: location_conf.tenant_conf,
+                location: attach_conf.clone(),
+            }),
+            LocationMode::Secondary(_) => {
+                anyhow::bail!("Attempted to construct AttachedTenantConf from a LocationConf in secondary mode")
+            }
+        }
+    }
+}
+
 ///
 /// Tenant consists of multiple timelines. Keep them in a hash table.
 ///
@@ -178,12 +202,15 @@ pub struct Tenant {
     // We keep TenantConfOpt sturct here to preserve the information
     // about parameters that are not set.
     // This is necessary to allow global config updates.
-    tenant_conf: Arc<RwLock<TenantConfOpt>>,
+    tenant_conf: Arc<RwLock<AttachedTenantConf>>,
 
     tenant_id: TenantId,
 
     /// The remote storage generation, used to protect S3 objects from split-brain.
     /// Does not change over the lifetime of the [`Tenant`] object.
+    ///  
+    /// This duplicates the generation stored in LocationConf, but that structure is mutable:
+    /// this copy enforces the invariant that generatio doesn't change during a Tenant's lifetime.
     generation: Generation,
 
     timelines: Mutex<HashMap<TimelineId, Arc<Timeline>>>,
@@ -527,14 +554,13 @@ impl Tenant {
     pub(crate) fn spawn_attach(
         conf: &'static PageServerConf,
         tenant_id: TenantId,
-        generation: Generation,
         resources: TenantSharedResources,
+        attached_conf: AttachedTenantConf,
         tenants: &'static tokio::sync::RwLock<TenantsMap>,
         ctx: &RequestContext,
     ) -> anyhow::Result<Arc<Tenant>> {
         // TODO dedup with spawn_load
-        let tenant_conf =
-            Self::load_tenant_config(conf, &tenant_id).context("load tenant config")?;
+        let wal_redo_manager = Arc::new(PostgresRedoManager::new(conf, tenant_id));
 
         let TenantSharedResources {
             broker_client,
@@ -542,14 +568,12 @@ impl Tenant {
             deletion_queue_client,
         } = resources;
 
-        let wal_redo_manager = Arc::new(PostgresRedoManager::new(conf, tenant_id));
         let tenant = Arc::new(Tenant::new(
             TenantState::Attaching,
             conf,
-            tenant_conf,
+            attached_conf,
             wal_redo_manager,
             tenant_id,
-            generation,
             remote_storage.clone(),
             deletion_queue_client,
         ));
@@ -772,7 +796,7 @@ impl Tenant {
         }
 
         std::fs::remove_file(&marker_file)
-            .with_context(|| format!("unlink attach marker file {}", marker_file.display()))?;
+            .with_context(|| format!("unlink attach marker file {marker_file}"))?;
         crashsafe::fsync(marker_file.parent().expect("marker file has parent dir"))
             .context("fsync tenant directory after unlinking attach marker file")?;
 
@@ -860,10 +884,9 @@ impl Tenant {
                 backtrace: String::new(),
             },
             conf,
-            TenantConfOpt::default(),
+            AttachedTenantConf::try_from(LocationConf::default()).unwrap(),
             wal_redo_manager,
             tenant_id,
-            Generation::broken(),
             None,
             DeletionQueueClient::broken(),
         ))
@@ -882,7 +905,7 @@ impl Tenant {
     pub(crate) fn spawn_load(
         conf: &'static PageServerConf,
         tenant_id: TenantId,
-        generation: Generation,
+        attached_conf: AttachedTenantConf,
         resources: TenantSharedResources,
         init_order: Option<InitializationOrder>,
         tenants: &'static tokio::sync::RwLock<TenantsMap>,
@@ -890,14 +913,6 @@ impl Tenant {
     ) -> Arc<Tenant> {
         span::debug_assert_current_span_has_tenant_id();
 
-        let tenant_conf = match Self::load_tenant_config(conf, &tenant_id) {
-            Ok(conf) => conf,
-            Err(e) => {
-                error!("load tenant config failed: {:?}", e);
-                return Tenant::create_broken_tenant(conf, tenant_id, format!("{e:#}"));
-            }
-        };
-
         let broker_client = resources.broker_client;
         let remote_storage = resources.remote_storage;
 
@@ -905,10 +920,9 @@ impl Tenant {
         let tenant = Tenant::new(
             TenantState::Loading,
             conf,
-            tenant_conf,
+            attached_conf,
             wal_redo_manager,
             tenant_id,
-            generation,
             remote_storage.clone(),
             resources.deletion_queue_client.clone(),
         );
@@ -1024,58 +1038,47 @@ impl Tenant {
 
         let timelines_dir = self.conf.timelines_path(&self.tenant_id);
 
-        for entry in
-            std::fs::read_dir(&timelines_dir).context("list timelines directory for tenant")?
+        for entry in timelines_dir
+            .read_dir_utf8()
+            .context("list timelines directory for tenant")?
         {
             let entry = entry.context("read timeline dir entry")?;
             let timeline_dir = entry.path();
 
-            if crate::is_temporary(&timeline_dir) {
-                info!(
-                    "Found temporary timeline directory, removing: {}",
-                    timeline_dir.display()
-                );
-                if let Err(e) = std::fs::remove_dir_all(&timeline_dir) {
-                    error!(
-                        "Failed to remove temporary directory '{}': {:?}",
-                        timeline_dir.display(),
-                        e
-                    );
+            if crate::is_temporary(timeline_dir) {
+                info!("Found temporary timeline directory, removing: {timeline_dir}");
+                if let Err(e) = std::fs::remove_dir_all(timeline_dir) {
+                    error!("Failed to remove temporary directory '{timeline_dir}': {e:?}");
                 }
-            } else if is_uninit_mark(&timeline_dir) {
+            } else if is_uninit_mark(timeline_dir) {
                 if !timeline_dir.exists() {
-                    warn!(
-                        "Timeline dir entry become invalid: {}",
-                        timeline_dir.display()
-                    );
+                    warn!("Timeline dir entry become invalid: {timeline_dir}");
                     continue;
                 }
 
                 let timeline_uninit_mark_file = &timeline_dir;
                 info!(
-                    "Found an uninit mark file {}, removing the timeline and its uninit mark",
-                    timeline_uninit_mark_file.display()
+                    "Found an uninit mark file {timeline_uninit_mark_file}, removing the timeline and its uninit mark",
                 );
-                let timeline_id = TimelineId::try_from(timeline_uninit_mark_file.file_stem())
-                    .with_context(|| {
-                        format!(
-                            "Could not parse timeline id out of the timeline uninit mark name {}",
-                            timeline_uninit_mark_file.display()
+                let timeline_id =
+                    TimelineId::try_from(timeline_uninit_mark_file.file_stem())
+                        .with_context(|| {
+                            format!(
+                            "Could not parse timeline id out of the timeline uninit mark name {timeline_uninit_mark_file}",
                         )
-                    })?;
+                        })?;
                 let timeline_dir = self.conf.timeline_path(&self.tenant_id, &timeline_id);
                 if let Err(e) =
                     remove_timeline_and_uninit_mark(&timeline_dir, timeline_uninit_mark_file)
                 {
                     error!("Failed to clean up uninit marked timeline: {e:?}");
                 }
-            } else if crate::is_delete_mark(&timeline_dir) {
+            } else if crate::is_delete_mark(timeline_dir) {
                 // If metadata exists, load as usual, continue deletion
-                let timeline_id =
-                    TimelineId::try_from(timeline_dir.file_stem()).with_context(|| {
+                let timeline_id = TimelineId::try_from(timeline_dir.file_stem())
+                    .with_context(|| {
                         format!(
-                            "Could not parse timeline id out of the timeline uninit mark name {}",
-                            timeline_dir.display()
+                            "Could not parse timeline id out of the timeline uninit mark name {timeline_dir}",
                         )
                     })?;
 
@@ -1114,17 +1117,13 @@ impl Tenant {
                 }
             } else {
                 if !timeline_dir.exists() {
-                    warn!(
-                        "Timeline dir entry become invalid: {}",
-                        timeline_dir.display()
-                    );
+                    warn!("Timeline dir entry become invalid: {timeline_dir}");
                     continue;
                 }
-                let timeline_id =
-                    TimelineId::try_from(timeline_dir.file_name()).with_context(|| {
+                let timeline_id = TimelineId::try_from(timeline_dir.file_name())
+                    .with_context(|| {
                         format!(
-                            "Could not parse timeline id out of the timeline dir name {}",
-                            timeline_dir.display()
+                            "Could not parse timeline id out of the timeline dir name {timeline_dir}",
                         )
                     })?;
                 let timeline_uninit_mark_file = self
@@ -1136,7 +1135,7 @@ impl Tenant {
                         "Found an uninit mark file, removing the timeline and its uninit mark",
                     );
                     if let Err(e) =
-                        remove_timeline_and_uninit_mark(&timeline_dir, &timeline_uninit_mark_file)
+                        remove_timeline_and_uninit_mark(timeline_dir, &timeline_uninit_mark_file)
                     {
                         error!("Failed to clean up uninit marked timeline: {e:?}");
                     }
@@ -1152,18 +1151,13 @@ impl Tenant {
                 }
 
                 let file_name = entry.file_name();
-                if let Ok(timeline_id) =
-                    file_name.to_str().unwrap_or_default().parse::<TimelineId>()
-                {
+                if let Ok(timeline_id) = file_name.parse::<TimelineId>() {
                     let metadata = load_metadata(self.conf, &self.tenant_id, &timeline_id)
                         .context("failed to load metadata")?;
                     timelines_to_load.insert(timeline_id, metadata);
                 } else {
                     // A file or directory that doesn't look like a timeline ID
-                    warn!(
-                        "unexpected file or directory in timelines directory: {}",
-                        file_name.to_string_lossy()
-                    );
+                    warn!("unexpected file or directory in timelines directory: {file_name}");
                 }
             }
         }
@@ -1667,6 +1661,15 @@ impl Tenant {
             "Cannot run GC iteration on inactive tenant"
         );
 
+        {
+            let conf = self.tenant_conf.read().unwrap();
+
+            if !conf.location.may_delete_layers_hint() {
+                info!("Skipping GC in location state {:?}", conf.location);
+                return Ok(GcResult::default());
+            }
+        }
+
         self.gc_iteration_internal(target_timeline_id, horizon, pitr, ctx)
             .await
     }
@@ -1685,6 +1688,14 @@ impl Tenant {
             "Cannot run compaction iteration on inactive tenant"
         );
 
+        {
+            let conf = self.tenant_conf.read().unwrap();
+            if !conf.location.may_delete_layers_hint() || !conf.location.may_upload_layers_hint() {
+                info!("Skipping compaction in location state {:?}", conf.location);
+                return Ok(());
+            }
+        }
+
         // Scan through the hashmap and collect a list of all the timelines,
         // while holding the lock. Then drop the lock and actually perform the
         // compactions.  We don't want to block everything else while the
@@ -2110,7 +2121,7 @@ where
 
 impl Tenant {
     pub fn tenant_specific_overrides(&self) -> TenantConfOpt {
-        *self.tenant_conf.read().unwrap()
+        self.tenant_conf.read().unwrap().tenant_conf
     }
 
     pub fn effective_config(&self) -> TenantConf {
@@ -2119,84 +2130,95 @@ impl Tenant {
     }
 
     pub fn get_checkpoint_distance(&self) -> u64 {
-        let tenant_conf = self.tenant_conf.read().unwrap();
+        let tenant_conf = self.tenant_conf.read().unwrap().tenant_conf;
         tenant_conf
             .checkpoint_distance
             .unwrap_or(self.conf.default_tenant_conf.checkpoint_distance)
     }
 
     pub fn get_checkpoint_timeout(&self) -> Duration {
-        let tenant_conf = self.tenant_conf.read().unwrap();
+        let tenant_conf = self.tenant_conf.read().unwrap().tenant_conf;
         tenant_conf
             .checkpoint_timeout
             .unwrap_or(self.conf.default_tenant_conf.checkpoint_timeout)
     }
 
     pub fn get_compaction_target_size(&self) -> u64 {
-        let tenant_conf = self.tenant_conf.read().unwrap();
+        let tenant_conf = self.tenant_conf.read().unwrap().tenant_conf;
         tenant_conf
             .compaction_target_size
             .unwrap_or(self.conf.default_tenant_conf.compaction_target_size)
     }
 
     pub fn get_compaction_period(&self) -> Duration {
-        let tenant_conf = self.tenant_conf.read().unwrap();
+        let tenant_conf = self.tenant_conf.read().unwrap().tenant_conf;
         tenant_conf
             .compaction_period
             .unwrap_or(self.conf.default_tenant_conf.compaction_period)
     }
 
     pub fn get_compaction_threshold(&self) -> usize {
-        let tenant_conf = self.tenant_conf.read().unwrap();
+        let tenant_conf = self.tenant_conf.read().unwrap().tenant_conf;
         tenant_conf
             .compaction_threshold
             .unwrap_or(self.conf.default_tenant_conf.compaction_threshold)
     }
 
     pub fn get_gc_horizon(&self) -> u64 {
-        let tenant_conf = self.tenant_conf.read().unwrap();
+        let tenant_conf = self.tenant_conf.read().unwrap().tenant_conf;
         tenant_conf
             .gc_horizon
             .unwrap_or(self.conf.default_tenant_conf.gc_horizon)
     }
 
     pub fn get_gc_period(&self) -> Duration {
-        let tenant_conf = self.tenant_conf.read().unwrap();
+        let tenant_conf = self.tenant_conf.read().unwrap().tenant_conf;
         tenant_conf
             .gc_period
             .unwrap_or(self.conf.default_tenant_conf.gc_period)
     }
 
     pub fn get_image_creation_threshold(&self) -> usize {
-        let tenant_conf = self.tenant_conf.read().unwrap();
+        let tenant_conf = self.tenant_conf.read().unwrap().tenant_conf;
         tenant_conf
             .image_creation_threshold
             .unwrap_or(self.conf.default_tenant_conf.image_creation_threshold)
     }
 
     pub fn get_pitr_interval(&self) -> Duration {
-        let tenant_conf = self.tenant_conf.read().unwrap();
+        let tenant_conf = self.tenant_conf.read().unwrap().tenant_conf;
         tenant_conf
             .pitr_interval
             .unwrap_or(self.conf.default_tenant_conf.pitr_interval)
     }
 
     pub fn get_trace_read_requests(&self) -> bool {
-        let tenant_conf = self.tenant_conf.read().unwrap();
+        let tenant_conf = self.tenant_conf.read().unwrap().tenant_conf;
         tenant_conf
             .trace_read_requests
             .unwrap_or(self.conf.default_tenant_conf.trace_read_requests)
     }
 
     pub fn get_min_resident_size_override(&self) -> Option<u64> {
-        let tenant_conf = self.tenant_conf.read().unwrap();
+        let tenant_conf = self.tenant_conf.read().unwrap().tenant_conf;
         tenant_conf
             .min_resident_size_override
             .or(self.conf.default_tenant_conf.min_resident_size_override)
     }
 
     pub fn set_new_tenant_config(&self, new_tenant_conf: TenantConfOpt) {
-        *self.tenant_conf.write().unwrap() = new_tenant_conf;
+        self.tenant_conf.write().unwrap().tenant_conf = new_tenant_conf;
+        // Don't hold self.timelines.lock() during the notifies.
+        // There's no risk of deadlock right now, but there could be if we consolidate
+        // mutexes in struct Timeline in the future.
+        let timelines = self.list_timelines();
+        for timeline in timelines {
+            timeline.tenant_conf_updated();
+        }
+    }
+
+    pub(crate) fn set_new_location_config(&self, new_conf: AttachedTenantConf) {
+        *self.tenant_conf.write().unwrap() = new_conf;
         // Don't hold self.timelines.lock() during the notifies.
         // There's no risk of deadlock right now, but there could be if we consolidate
         // mutexes in struct Timeline in the future.
@@ -2266,10 +2288,9 @@ impl Tenant {
     fn new(
         state: TenantState,
         conf: &'static PageServerConf,
-        tenant_conf: TenantConfOpt,
+        attached_conf: AttachedTenantConf,
         walredo_mgr: Arc<dyn WalRedoManager + Send + Sync>,
         tenant_id: TenantId,
-        generation: Generation,
         remote_storage: Option<GenericRemoteStorage>,
         deletion_queue_client: DeletionQueueClient,
     ) -> Tenant {
@@ -2329,12 +2350,12 @@ impl Tenant {
 
         Tenant {
             tenant_id,
-            generation,
+            generation: attached_conf.location.generation,
             conf,
             // using now here is good enough approximation to catch tenants with really long
             // activation times.
             loading_started_at: Instant::now(),
-            tenant_conf: Arc::new(RwLock::new(tenant_conf)),
+            tenant_conf: Arc::new(RwLock::new(attached_conf)),
             timelines: Mutex::new(HashMap::new()),
             gc_cs: tokio::sync::Mutex::new(()),
             walredo_mgr,
@@ -2352,54 +2373,124 @@ impl Tenant {
     pub(super) fn load_tenant_config(
         conf: &'static PageServerConf,
         tenant_id: &TenantId,
-    ) -> anyhow::Result<TenantConfOpt> {
-        let target_config_path = conf.tenant_config_path(tenant_id);
-        let target_config_display = target_config_path.display();
+    ) -> anyhow::Result<LocationConf> {
+        let legacy_config_path = conf.tenant_config_path(tenant_id);
+        let config_path = conf.tenant_location_config_path(tenant_id);
 
-        info!("loading tenantconf from {target_config_display}");
+        if config_path.exists() {
+            // New-style config takes precedence
+            let deserialized = Self::read_config(&config_path)?;
+            Ok(toml_edit::de::from_document::<LocationConf>(deserialized)?)
+        } else if legacy_config_path.exists() {
+            // Upgrade path: found an old-style configuration only
+            let deserialized = Self::read_config(&legacy_config_path)?;
 
-        // FIXME If the config file is not found, assume that we're attaching
-        // a detached tenant and config is passed via attach command.
-        // https://github.com/neondatabase/neon/issues/1555
-        // OR: we're loading after incomplete deletion that managed to remove config.
-        if !target_config_path.exists() {
-            info!("tenant config not found in {target_config_display}");
-            return Ok(TenantConfOpt::default());
+            let mut tenant_conf = TenantConfOpt::default();
+            for (key, item) in deserialized.iter() {
+                match key {
+                    "tenant_config" => {
+                        tenant_conf = PageServerConf::parse_toml_tenant_conf(item).with_context(|| {
+                            format!("Failed to parse config from file '{legacy_config_path}' as pageserver config")
+                        })?;
+                    }
+                    _ => bail!(
+                        "config file {legacy_config_path} has unrecognized pageserver option '{key}'"
+                    ),
+                }
+            }
+
+            // Legacy configs are implicitly in attached state
+            Ok(LocationConf::attached_single(
+                tenant_conf,
+                Generation::none(),
+            ))
+        } else {
+            // FIXME If the config file is not found, assume that we're attaching
+            // a detached tenant and config is passed via attach command.
+            // https://github.com/neondatabase/neon/issues/1555
+            // OR: we're loading after incomplete deletion that managed to remove config.
+            info!(
+                "tenant config not found in {} or {}",
+                config_path, legacy_config_path
+            );
+            Ok(LocationConf::default())
         }
+    }
+
+    fn read_config(path: &Utf8Path) -> anyhow::Result<toml_edit::Document> {
+        info!("loading tenant configuration from {path}");
 
         // load and parse file
-        let config = fs::read_to_string(&target_config_path).with_context(|| {
-            format!("Failed to load config from path '{target_config_display}'")
-        })?;
+        let config = fs::read_to_string(path)
+            .with_context(|| format!("Failed to load config from path '{path}'"))?;
 
-        let toml = config.parse::<toml_edit::Document>().with_context(|| {
-            format!("Failed to parse config from file '{target_config_display}' as toml file")
-        })?;
-
-        let mut tenant_conf = TenantConfOpt::default();
-        for (key, item) in toml.iter() {
-            match key {
-                "tenant_config" => {
-                    tenant_conf = PageServerConf::parse_toml_tenant_conf(item).with_context(|| {
-                        format!("Failed to parse config from file '{target_config_display}' as pageserver config")
-                    })?;
-                }
-                _ => bail!("config file {target_config_display} has unrecognized pageserver option '{key}'"),
-
-            }
-        }
-
-        Ok(tenant_conf)
+        config
+            .parse::<toml_edit::Document>()
+            .with_context(|| format!("Failed to parse config from file '{path}' as toml file"))
     }
 
     #[tracing::instrument(skip_all, fields(%tenant_id))]
     pub(super) async fn persist_tenant_config(
+        conf: &'static PageServerConf,
         tenant_id: &TenantId,
-        target_config_path: &Path,
-        tenant_conf: TenantConfOpt,
+        location_conf: &LocationConf,
     ) -> anyhow::Result<()> {
-        // imitate a try-block with a closure
-        info!("persisting tenantconf to {}", target_config_path.display());
+        let legacy_config_path = conf.tenant_config_path(tenant_id);
+        let config_path = conf.tenant_location_config_path(tenant_id);
+        Self::persist_tenant_config_at(tenant_id, &config_path, &legacy_config_path, location_conf)
+            .await
+    }
+
+    #[tracing::instrument(skip_all, fields(%tenant_id))]
+    pub(super) async fn persist_tenant_config_at(
+        tenant_id: &TenantId,
+        config_path: &Utf8Path,
+        legacy_config_path: &Utf8Path,
+        location_conf: &LocationConf,
+    ) -> anyhow::Result<()> {
+        // Forward compat: write out an old-style configuration that old versions can read, in case we roll back
+        Self::persist_tenant_config_legacy(
+            tenant_id,
+            legacy_config_path,
+            &location_conf.tenant_conf,
+        )
+        .await?;
+
+        if let LocationMode::Attached(attach_conf) = &location_conf.mode {
+            // Once we use LocationMode, generations are mandatory.  If we aren't using generations,
+            // then drop out after writing legacy-style config.
+            if attach_conf.generation.is_none() {
+                tracing::debug!("Running without generations, not writing new-style LocationConf");
+                return Ok(());
+            }
+        }
+
+        info!("persisting tenantconf to {config_path}");
+
+        let mut conf_content = r#"# This file contains a specific per-tenant's config.
+#  It is read in case of pageserver restart.
+"#
+        .to_string();
+
+        // Convert the config to a toml file.
+        conf_content += &toml_edit::ser::to_string_pretty(&location_conf)?;
+
+        let conf_content = conf_content.as_bytes();
+
+        let temp_path = path_with_suffix_extension(config_path, TEMP_FILE_SUFFIX);
+        VirtualFile::crashsafe_overwrite(config_path, &temp_path, conf_content)
+            .await
+            .with_context(|| format!("write tenant {tenant_id} config to {config_path}"))?;
+        Ok(())
+    }
+
+    #[tracing::instrument(skip_all, fields(%tenant_id))]
+    async fn persist_tenant_config_legacy(
+        tenant_id: &TenantId,
+        target_config_path: &Utf8Path,
+        tenant_conf: &TenantConfOpt,
+    ) -> anyhow::Result<()> {
+        info!("persisting tenantconf to {target_config_path}");
 
         let mut conf_content = r#"# This file contains a specific per-tenant's config.
 #  It is read in case of pageserver restart.
@@ -2416,12 +2507,7 @@ impl Tenant {
         let temp_path = path_with_suffix_extension(target_config_path, TEMP_FILE_SUFFIX);
         VirtualFile::crashsafe_overwrite(target_config_path, &temp_path, conf_content)
             .await
-            .with_context(|| {
-                format!(
-                    "write tenant {tenant_id} config to {}",
-                    target_config_path.display()
-                )
-            })?;
+            .with_context(|| format!("write tenant {tenant_id} config to {target_config_path}"))?;
         Ok(())
     }
 
@@ -2788,10 +2874,7 @@ impl Tenant {
         // current initdb was not run yet, so remove whatever was left from the previous runs
         if initdb_path.exists() {
             fs::remove_dir_all(&initdb_path).with_context(|| {
-                format!(
-                    "Failed to remove already existing initdb directory: {}",
-                    initdb_path.display()
-                )
+                format!("Failed to remove already existing initdb directory: {initdb_path}")
             })?;
         }
         // Init temporarily repo to get bootstrap data, this creates a directory in the `initdb_path` path
@@ -2800,7 +2883,7 @@ impl Tenant {
         scopeguard::defer! {
             if let Err(e) = fs::remove_dir_all(&initdb_path) {
                 // this is unlikely, but we will remove the directory on pageserver restart or another bootstrap call
-                error!("Failed to remove temporary initdb directory '{}': {}", initdb_path.display(), e);
+                error!("Failed to remove temporary initdb directory '{initdb_path}': {e}");
             }
         }
         let pgdata_path = &initdb_path;
@@ -2950,7 +3033,7 @@ impl Tenant {
 
     async fn create_timeline_files(
         &self,
-        timeline_path: &Path,
+        timeline_path: &Utf8Path,
         new_timeline_id: &TimelineId,
         new_metadata: &TimelineMetadata,
     ) -> anyhow::Result<()> {
@@ -2984,8 +3067,7 @@ impl Tenant {
         let timeline_path = self.conf.timeline_path(&tenant_id, &timeline_id);
         anyhow::ensure!(
             !timeline_path.exists(),
-            "Timeline {} already exists, cannot create its uninit mark file",
-            timeline_path.display()
+            "Timeline {timeline_path} already exists, cannot create its uninit mark file",
         );
 
         let uninit_mark_path = self
@@ -3077,7 +3159,10 @@ impl Tenant {
     }
 }
 
-fn remove_timeline_and_uninit_mark(timeline_dir: &Path, uninit_mark: &Path) -> anyhow::Result<()> {
+fn remove_timeline_and_uninit_mark(
+    timeline_dir: &Utf8Path,
+    uninit_mark: &Utf8Path,
+) -> anyhow::Result<()> {
     fs::remove_dir_all(timeline_dir)
         .or_else(|e| {
             if e.kind() == std::io::ErrorKind::NotFound {
@@ -3089,17 +3174,10 @@ fn remove_timeline_and_uninit_mark(timeline_dir: &Path, uninit_mark: &Path) -> a
             }
         })
         .with_context(|| {
-            format!(
-                "Failed to remove unit marked timeline directory {}",
-                timeline_dir.display()
-            )
+            format!("Failed to remove unit marked timeline directory {timeline_dir}")
         })?;
-    fs::remove_file(uninit_mark).with_context(|| {
-        format!(
-            "Failed to remove timeline uninit mark file {}",
-            uninit_mark.display()
-        )
-    })?;
+    fs::remove_file(uninit_mark)
+        .with_context(|| format!("Failed to remove timeline uninit mark file {uninit_mark}"))?;
 
     Ok(())
 }
@@ -3111,10 +3189,10 @@ pub(crate) enum CreateTenantFilesMode {
 
 pub(crate) async fn create_tenant_files(
     conf: &'static PageServerConf,
-    tenant_conf: TenantConfOpt,
+    location_conf: &LocationConf,
     tenant_id: &TenantId,
     mode: CreateTenantFilesMode,
-) -> anyhow::Result<PathBuf> {
+) -> anyhow::Result<Utf8PathBuf> {
     let target_tenant_directory = conf.tenant_path(tenant_id);
     anyhow::ensure!(
         !target_tenant_directory
@@ -3125,22 +3203,16 @@ pub(crate) async fn create_tenant_files(
 
     let temporary_tenant_dir =
         path_with_suffix_extension(&target_tenant_directory, TEMP_FILE_SUFFIX);
-    debug!(
-        "Creating temporary directory structure in {}",
-        temporary_tenant_dir.display()
-    );
+    debug!("Creating temporary directory structure in {temporary_tenant_dir}");
 
     // top-level dir may exist if we are creating it through CLI
     crashsafe::create_dir_all(&temporary_tenant_dir).with_context(|| {
-        format!(
-            "could not create temporary tenant directory {}",
-            temporary_tenant_dir.display()
-        )
+        format!("could not create temporary tenant directory {temporary_tenant_dir}")
     })?;
 
     let creation_result = try_create_target_tenant_dir(
         conf,
-        tenant_conf,
+        location_conf,
         tenant_id,
         mode,
         &temporary_tenant_dir,
@@ -3166,11 +3238,11 @@ pub(crate) async fn create_tenant_files(
 
 async fn try_create_target_tenant_dir(
     conf: &'static PageServerConf,
-    tenant_conf: TenantConfOpt,
+    location_conf: &LocationConf,
     tenant_id: &TenantId,
     mode: CreateTenantFilesMode,
-    temporary_tenant_dir: &Path,
-    target_tenant_directory: &Path,
+    temporary_tenant_dir: &Utf8Path,
+    target_tenant_directory: &Utf8Path,
 ) -> Result<(), anyhow::Error> {
     match mode {
         CreateTenantFilesMode::Create => {} // needs no attach marker, writing tenant conf + atomic rename of dir is good enough
@@ -3196,20 +3268,31 @@ async fn try_create_target_tenant_dir(
         temporary_tenant_dir,
     )
     .with_context(|| format!("resolve tenant {tenant_id} temporary timelines dir"))?;
-    let temporary_tenant_config_path = rebase_directory(
+    let temporary_legacy_tenant_config_path = rebase_directory(
         &conf.tenant_config_path(tenant_id),
         target_tenant_directory,
         temporary_tenant_dir,
     )
     .with_context(|| format!("resolve tenant {tenant_id} temporary config path"))?;
+    let temporary_tenant_config_path = rebase_directory(
+        &conf.tenant_location_config_path(tenant_id),
+        target_tenant_directory,
+        temporary_tenant_dir,
+    )
+    .with_context(|| format!("resolve tenant {tenant_id} temporary config path"))?;
 
-    Tenant::persist_tenant_config(tenant_id, &temporary_tenant_config_path, tenant_conf).await?;
+    Tenant::persist_tenant_config_at(
+        tenant_id,
+        &temporary_tenant_config_path,
+        &temporary_legacy_tenant_config_path,
+        location_conf,
+    )
+    .await?;
 
     crashsafe::create_dir(&temporary_tenant_timelines_dir).with_context(|| {
         format!(
             "create tenant {} temporary timelines directory {}",
-            tenant_id,
-            temporary_tenant_timelines_dir.display()
+            tenant_id, temporary_tenant_timelines_dir,
         )
     })?;
     fail::fail_point!("tenant-creation-before-tmp-rename", |_| {
@@ -3224,35 +3307,34 @@ async fn try_create_target_tenant_dir(
     fs::rename(temporary_tenant_dir, target_tenant_directory).with_context(|| {
         format!(
             "move tenant {} temporary directory {} into the permanent one {}",
-            tenant_id,
-            temporary_tenant_dir.display(),
-            target_tenant_directory.display()
+            tenant_id, temporary_tenant_dir, target_tenant_directory
         )
     })?;
     let target_dir_parent = target_tenant_directory.parent().with_context(|| {
         format!(
             "get tenant {} dir parent for {}",
-            tenant_id,
-            target_tenant_directory.display()
+            tenant_id, target_tenant_directory,
         )
     })?;
     crashsafe::fsync(target_dir_parent).with_context(|| {
         format!(
             "fsync renamed directory's parent {} for tenant {}",
-            target_dir_parent.display(),
-            tenant_id,
+            target_dir_parent, tenant_id,
         )
     })?;
 
     Ok(())
 }
 
-fn rebase_directory(original_path: &Path, base: &Path, new_base: &Path) -> anyhow::Result<PathBuf> {
+fn rebase_directory(
+    original_path: &Utf8Path,
+    base: &Utf8Path,
+    new_base: &Utf8Path,
+) -> anyhow::Result<Utf8PathBuf> {
     let relative_path = original_path.strip_prefix(base).with_context(|| {
         format!(
             "Failed to strip base prefix '{}' off path '{}'",
-            base.display(),
-            original_path.display()
+            base, original_path
         )
     })?;
     Ok(new_base.join(relative_path))
@@ -3262,20 +3344,18 @@ fn rebase_directory(original_path: &Path, base: &Path, new_base: &Path) -> anyho
 /// to get bootstrap data for timeline initialization.
 fn run_initdb(
     conf: &'static PageServerConf,
-    initdb_target_dir: &Path,
+    initdb_target_dir: &Utf8Path,
     pg_version: u32,
 ) -> anyhow::Result<()> {
     let initdb_bin_path = conf.pg_bin_dir(pg_version)?.join("initdb");
     let initdb_lib_dir = conf.pg_lib_dir(pg_version)?;
     info!(
         "running {} in {}, libdir: {}",
-        initdb_bin_path.display(),
-        initdb_target_dir.display(),
-        initdb_lib_dir.display(),
+        initdb_bin_path, initdb_target_dir, initdb_lib_dir,
     );
 
     let initdb_output = Command::new(&initdb_bin_path)
-        .args(["-D", &initdb_target_dir.to_string_lossy()])
+        .args(["-D", initdb_target_dir.as_ref()])
         .args(["-U", &conf.superuser])
         .args(["-E", "utf8"])
         .arg("--no-instructions")
@@ -3290,8 +3370,7 @@ fn run_initdb(
         .with_context(|| {
             format!(
                 "failed to execute {} at target dir {}",
-                initdb_bin_path.display(),
-                initdb_target_dir.display()
+                initdb_bin_path, initdb_target_dir,
             )
         })?;
     if !initdb_output.status.success() {
@@ -3311,7 +3390,7 @@ impl Drop for Tenant {
 }
 /// Dump contents of a layer file to stdout.
 pub async fn dump_layerfile_from_path(
-    path: &Path,
+    path: &Utf8Path,
     verbose: bool,
     ctx: &RequestContext,
 ) -> anyhow::Result<()> {
@@ -3344,8 +3423,8 @@ pub async fn dump_layerfile_from_path(
 pub mod harness {
     use bytes::{Bytes, BytesMut};
     use once_cell::sync::OnceCell;
+    use std::fs;
     use std::sync::Arc;
-    use std::{fs, path::PathBuf};
     use utils::logging;
     use utils::lsn::Lsn;
 
@@ -3410,7 +3489,7 @@ pub mod harness {
         pub tenant_id: TenantId,
         pub generation: Generation,
         pub remote_storage: GenericRemoteStorage,
-        pub remote_fs_dir: PathBuf,
+        pub remote_fs_dir: Utf8PathBuf,
         pub deletion_queue: MockDeletionQueue,
     }
 
@@ -3489,10 +3568,13 @@ pub mod harness {
             let tenant = Arc::new(Tenant::new(
                 TenantState::Loading,
                 self.conf,
-                TenantConfOpt::from(self.tenant_conf),
+                AttachedTenantConf::try_from(LocationConf::attached_single(
+                    TenantConfOpt::from(self.tenant_conf),
+                    self.generation,
+                ))
+                .unwrap(),
                 walredo_mgr,
                 self.tenant_id,
-                self.generation,
                 Some(self.remote_storage.clone()),
                 self.deletion_queue.new_client(),
             ));
@@ -3509,7 +3591,7 @@ pub mod harness {
             Ok(tenant)
         }
 
-        pub fn timeline_path(&self, timeline_id: &TimelineId) -> PathBuf {
+        pub fn timeline_path(&self, timeline_id: &TimelineId) -> Utf8PathBuf {
             self.conf.timeline_path(&self.tenant_id, timeline_id)
         }
     }

pageserver/src/tenant/blob_io.rs

@@ -20,10 +20,10 @@ use std::io::{Error, ErrorKind};
 
 impl<'a> BlockCursor<'a> {
     /// Read a blob into a new buffer.
-    pub async fn read_blob(
+    pub async fn read_blob<'c>(
         &self,
         offset: u64,
-        ctx: &RequestContext,
+        ctx: &'c RequestContext,
     ) -> Result<Vec<u8>, std::io::Error> {
         let mut buf = Vec::new();
         self.read_blob_into_buf(offset, &mut buf, ctx).await?;
@@ -31,11 +31,11 @@ impl<'a> BlockCursor<'a> {
     }
     /// Read blob into the given buffer. Any previous contents in the buffer
     /// are overwritten.
-    pub async fn read_blob_into_buf(
+    pub async fn read_blob_into_buf<'c>(
         &self,
         offset: u64,
         dstbuf: &mut Vec<u8>,
-        ctx: &RequestContext,
+        ctx: &'c RequestContext,
     ) -> Result<(), std::io::Error> {
         let mut blknum = (offset / PAGE_SZ as u64) as u32;
         let mut off = (offset % PAGE_SZ as u64) as usize;
@@ -238,14 +238,14 @@ mod tests {
     use rand::{Rng, SeedableRng};
 
     async fn round_trip_test<const BUFFERED: bool>(blobs: &[Vec<u8>]) -> Result<(), Error> {
-        let temp_dir = tempfile::tempdir()?;
-        let path = temp_dir.path().join("file");
+        let temp_dir = camino_tempfile::tempdir()?;
+        let pathbuf = temp_dir.path().join("file");
         let ctx = RequestContext::new(TaskKind::UnitTest, DownloadBehavior::Error);
 
         // Write part (in block to drop the file)
         let mut offsets = Vec::new();
         {
-            let file = VirtualFile::create(&path).await?;
+            let file = VirtualFile::create(pathbuf.as_path()).await?;
             let mut wtr = BlobWriter::<BUFFERED>::new(file, 0);
             for blob in blobs.iter() {
                 let offs = wtr.write_blob(blob).await?;
@@ -258,7 +258,7 @@ mod tests {
             wtr.flush_buffer().await?;
         }
 
-        let file = VirtualFile::open(&path).await?;
+        let file = VirtualFile::open(pathbuf.as_path()).await?;
         let rdr = BlockReaderRef::VirtualFile(&file);
         let rdr = BlockCursor::new(rdr);
         for (idx, (blob, offset)) in blobs.iter().zip(offsets.iter()).enumerate() {

pageserver/src/tenant/block_io.rs

@@ -34,27 +34,27 @@ where
 }
 
 /// Reference to an in-memory copy of an immutable on-disk block.
-pub enum BlockLease<'a> {
-    PageReadGuard(PageReadGuard<'static>),
+pub enum BlockLease<'c, 'a> {
+    PageReadGuard(PageReadGuard<'c, 'static>),
     EphemeralFileMutableTail(&'a [u8; PAGE_SZ]),
     #[cfg(test)]
     Arc(std::sync::Arc<[u8; PAGE_SZ]>),
 }
 
-impl From<PageReadGuard<'static>> for BlockLease<'static> {
-    fn from(value: PageReadGuard<'static>) -> BlockLease<'static> {
+impl<'c, 'a> From<PageReadGuard<'c, 'a>> for BlockLease<'c, 'a> {
+    fn from(value: PageReadGuard<'c, 'a>) -> BlockLease<'c, 'a> {
         BlockLease::PageReadGuard(value)
     }
 }
 
 #[cfg(test)]
-impl<'a> From<std::sync::Arc<[u8; PAGE_SZ]>> for BlockLease<'a> {
+impl<'c, 'a> From<std::sync::Arc<[u8; PAGE_SZ]>> for BlockLease<'c, 'a> {
     fn from(value: std::sync::Arc<[u8; PAGE_SZ]>) -> Self {
         BlockLease::Arc(value)
     }
 }
 
-impl<'a> Deref for BlockLease<'a> {
+impl<'c, 'a> Deref for BlockLease<'c, 'a> {
     type Target = [u8; PAGE_SZ];
 
     fn deref(&self) -> &Self::Target {
@@ -83,11 +83,11 @@ pub(crate) enum BlockReaderRef<'a> {
 
 impl<'a> BlockReaderRef<'a> {
     #[inline(always)]
-    async fn read_blk(
+    async fn read_blk<'c>(
         &self,
         blknum: u32,
-        ctx: &RequestContext,
-    ) -> Result<BlockLease, std::io::Error> {
+        ctx: &'c RequestContext,
+    ) -> Result<BlockLease<'c, '_>, std::io::Error> {
         use BlockReaderRef::*;
         match self {
             FileBlockReader(r) => r.read_blk(blknum, ctx).await,
@@ -141,11 +141,11 @@ impl<'a> BlockCursor<'a> {
     /// access to the contents of the page. (For the page cache, the
     /// lease object represents a lock on the buffer.)
     #[inline(always)]
-    pub async fn read_blk(
+    pub async fn read_blk<'c>(
         &self,
         blknum: u32,
-        ctx: &RequestContext,
-    ) -> Result<BlockLease, std::io::Error> {
+        ctx: &'c RequestContext,
+    ) -> Result<BlockLease<'c, '_>, std::io::Error> {
         self.reader.read_blk(blknum, ctx).await
     }
 }
@@ -180,32 +180,27 @@ impl FileBlockReader {
     /// Returns a "lease" object that can be used to
     /// access to the contents of the page. (For the page cache, the
     /// lease object represents a lock on the buffer.)
-    pub async fn read_blk(
+    pub async fn read_blk<'c>(
         &self,
         blknum: u32,
-        ctx: &RequestContext,
-    ) -> Result<BlockLease, std::io::Error> {
+        ctx: &'c RequestContext,
+    ) -> Result<BlockLease<'c, 'static>, std::io::Error> {
         let cache = page_cache::get();
-        loop {
-            match cache
-                .read_immutable_buf(self.file_id, blknum, ctx)
-                .await
-                .map_err(|e| {
-                    std::io::Error::new(
-                        std::io::ErrorKind::Other,
-                        format!("Failed to read immutable buf: {e:#}"),
-                    )
-                })? {
-                ReadBufResult::Found(guard) => break Ok(guard.into()),
-                ReadBufResult::NotFound(mut write_guard) => {
-                    // Read the page from disk into the buffer
-                    self.fill_buffer(write_guard.deref_mut(), blknum).await?;
-                    write_guard.mark_valid();
-
-                    // Swap for read lock
-                    continue;
-                }
-            };
+        match cache
+            .read_immutable_buf(self.file_id, blknum, ctx)
+            .await
+            .map_err(|e| {
+                std::io::Error::new(
+                    std::io::ErrorKind::Other,
+                    format!("Failed to read immutable buf: {e:#}"),
+                )
+            })? {
+            ReadBufResult::Found(guard) => Ok(guard.into()),
+            ReadBufResult::NotFound(mut write_guard) => {
+                // Read the page from disk into the buffer
+                self.fill_buffer(write_guard.deref_mut(), blknum).await?;
+                Ok(write_guard.mark_valid().into())
+            }
         }
     }
 }

pageserver/src/tenant/config.rs

@@ -13,6 +13,7 @@ use pageserver_api::models;
 use serde::{Deserialize, Serialize};
 use std::num::NonZeroU64;
 use std::time::Duration;
+use utils::generation::Generation;
 
 pub mod defaults {
     // FIXME: This current value is very low. I would imagine something like 1 GB or 10 GB
@@ -44,7 +45,211 @@ pub mod defaults {
     pub const DEFAULT_EVICTIONS_LOW_RESIDENCE_DURATION_METRIC_THRESHOLD: &str = "24 hour";
 }
 
-/// Per-tenant configuration options
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
+pub(crate) enum AttachmentMode {
+    /// Our generation is current as far as we know, and as far as we know we are the only attached
+    /// pageserver.  This is the "normal" attachment mode.
+    Single,
+    /// Our generation number is current as far as we know, but we are advised that another
+    /// pageserver is still attached, and therefore to avoid executing deletions.   This is
+    /// the attachment mode of a pagesever that is the destination of a migration.
+    Multi,
+    /// Our generation number is superseded, or about to be superseded.  We are advised
+    /// to avoid remote storage writes if possible, and to avoid sending billing data.  This
+    /// is the attachment mode of a pageserver that is the origin of a migration.
+    Stale,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
+pub(crate) struct AttachedLocationConfig {
+    pub(crate) generation: Generation,
+    pub(crate) attach_mode: AttachmentMode,
+    // TODO: add a flag to override AttachmentMode's policies under
+    // disk pressure (i.e. unblock uploads under disk pressure in Stale
+    // state, unblock deletions after timeout in Multi state)
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
+pub(crate) struct SecondaryLocationConfig {
+    /// If true, keep the local cache warm by polling remote storage
+    pub(crate) warm: bool,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
+pub(crate) enum LocationMode {
+    Attached(AttachedLocationConfig),
+    Secondary(SecondaryLocationConfig),
+}
+
+/// Per-tenant, per-pageserver configuration.  All pageservers use the same TenantConf,
+/// but have distinct LocationConf.
+#[derive(Clone, PartialEq, Eq, Serialize, Deserialize)]
+pub(crate) struct LocationConf {
+    /// The location-specific part of the configuration, describes the operating
+    /// mode of this pageserver for this tenant.
+    pub(crate) mode: LocationMode,
+    /// The pan-cluster tenant configuration, the same on all locations
+    pub(crate) tenant_conf: TenantConfOpt,
+}
+
+impl std::fmt::Debug for LocationConf {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match &self.mode {
+            LocationMode::Attached(conf) => {
+                write!(
+                    f,
+                    "Attached {:?}, gen={:?}",
+                    conf.attach_mode, conf.generation
+                )
+            }
+            LocationMode::Secondary(conf) => {
+                write!(f, "Secondary, warm={}", conf.warm)
+            }
+        }
+    }
+}
+
+impl AttachedLocationConfig {
+    /// Consult attachment mode to determine whether we are currently permitted
+    /// to delete layers.  This is only advisory, not required for data safety.
+    /// See [`AttachmentMode`] for more context.
+    pub(crate) fn may_delete_layers_hint(&self) -> bool {
+        // TODO: add an override for disk pressure in AttachedLocationConfig,
+        // and respect it here.
+        match &self.attach_mode {
+            AttachmentMode::Single => true,
+            AttachmentMode::Multi | AttachmentMode::Stale => {
+                // In Multi mode we avoid doing deletions because some other
+                // attached pageserver might get 404 while trying to read
+                // a layer we delete which is still referenced in their metadata.
+                //
+                // In Stale mode, we avoid doing deletions because we expect
+                // that they would ultimately fail validation in the deletion
+                // queue due to our stale generation.
+                false
+            }
+        }
+    }
+
+    /// Whether we are currently hinted that it is worthwhile to upload layers.
+    /// This is only advisory, not required for data safety.
+    /// See [`AttachmentMode`] for more context.
+    pub(crate) fn may_upload_layers_hint(&self) -> bool {
+        // TODO: add an override for disk pressure in AttachedLocationConfig,
+        // and respect it here.
+        match &self.attach_mode {
+            AttachmentMode::Single | AttachmentMode::Multi => true,
+            AttachmentMode::Stale => {
+                // In Stale mode, we avoid doing uploads because we expect that
+                // our replacement pageserver will already have started its own
+                // IndexPart that will never reference layers we upload: it is
+                // wasteful.
+                false
+            }
+        }
+    }
+}
+
+impl LocationConf {
+    /// For use when loading from a legacy configuration: presence of a tenant
+    /// implies it is in AttachmentMode::Single, which used to be the only
+    /// possible state.  This function should eventually be removed.
+    pub(crate) fn attached_single(tenant_conf: TenantConfOpt, generation: Generation) -> Self {
+        Self {
+            mode: LocationMode::Attached(AttachedLocationConfig {
+                generation,
+                attach_mode: AttachmentMode::Single,
+            }),
+            tenant_conf,
+        }
+    }
+
+    /// For use when attaching/re-attaching: update the generation stored in this
+    /// structure.  If we were in a secondary state, promote to attached (posession
+    /// of a fresh generation implies this).
+    pub(crate) fn attach_in_generation(&mut self, generation: Generation) {
+        match &mut self.mode {
+            LocationMode::Attached(attach_conf) => {
+                attach_conf.generation = generation;
+            }
+            LocationMode::Secondary(_) => {
+                // We are promoted to attached by the control plane's re-attach response
+                self.mode = LocationMode::Attached(AttachedLocationConfig {
+                    generation,
+                    attach_mode: AttachmentMode::Single,
+                })
+            }
+        }
+    }
+
+    pub(crate) fn try_from(conf: &'_ models::LocationConfig) -> anyhow::Result<Self> {
+        let tenant_conf = TenantConfOpt::try_from(&conf.tenant_conf)?;
+
+        fn get_generation(conf: &'_ models::LocationConfig) -> Result<Generation, anyhow::Error> {
+            conf.generation
+                .ok_or_else(|| anyhow::anyhow!("Generation must be set when attaching"))
+        }
+
+        let mode = match &conf.mode {
+            models::LocationConfigMode::AttachedMulti => {
+                LocationMode::Attached(AttachedLocationConfig {
+                    generation: get_generation(conf)?,
+                    attach_mode: AttachmentMode::Multi,
+                })
+            }
+            models::LocationConfigMode::AttachedSingle => {
+                LocationMode::Attached(AttachedLocationConfig {
+                    generation: get_generation(conf)?,
+                    attach_mode: AttachmentMode::Single,
+                })
+            }
+            models::LocationConfigMode::AttachedStale => {
+                LocationMode::Attached(AttachedLocationConfig {
+                    generation: get_generation(conf)?,
+                    attach_mode: AttachmentMode::Stale,
+                })
+            }
+            models::LocationConfigMode::Secondary => {
+                anyhow::ensure!(conf.generation.is_none());
+
+                let warm = conf
+                    .secondary_conf
+                    .as_ref()
+                    .map(|c| c.warm)
+                    .unwrap_or(false);
+                LocationMode::Secondary(SecondaryLocationConfig { warm })
+            }
+            models::LocationConfigMode::Detached => {
+                // Should not have been called: API code should translate this mode
+                // into a detach rather than trying to decode it as a LocationConf
+                return Err(anyhow::anyhow!("Cannot decode a Detached configuration"));
+            }
+        };
+
+        Ok(Self { mode, tenant_conf })
+    }
+}
+
+impl Default for LocationConf {
+    // TODO: this should be removed once tenant loading can guarantee that we are never
+    // loading from a directory without a configuration.
+    // => tech debt since https://github.com/neondatabase/neon/issues/1555
+    fn default() -> Self {
+        Self {
+            mode: LocationMode::Attached(AttachedLocationConfig {
+                generation: Generation::none(),
+                attach_mode: AttachmentMode::Single,
+            }),
+            tenant_conf: TenantConfOpt::default(),
+        }
+    }
+}
+
+/// A tenant's calcuated configuration, which is the result of merging a
+/// tenant's TenantConfOpt with the global TenantConf from PageServerConf.
+///
+/// For storing and transmitting individual tenant's configuration, see
+/// TenantConfOpt.
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
 pub struct TenantConf {
     // Flush out an inmemory layer, if it's holding WAL older than this

pageserver/src/tenant/delete.rs

@@ -1,9 +1,7 @@
-use std::{
-    path::{Path, PathBuf},
-    sync::Arc,
-};
+use std::sync::Arc;
 
 use anyhow::Context;
+use camino::{Utf8Path, Utf8PathBuf};
 use pageserver_api::models::TenantState;
 use remote_storage::{DownloadError, GenericRemoteStorage, RemotePath};
 use tokio::sync::OwnedMutexGuard;
@@ -62,7 +60,7 @@ fn remote_tenant_delete_mark_path(
         .context("Failed to strip workdir prefix")
         .and_then(RemotePath::new)
         .context("tenant path")?;
-    Ok(tenant_remote_path.join(Path::new("deleted")))
+    Ok(tenant_remote_path.join(Utf8Path::new("deleted")))
 }
 
 async fn create_remote_delete_mark(
@@ -148,7 +146,7 @@ async fn schedule_ordered_timeline_deletions(
     Ok(already_running_deletions)
 }
 
-async fn ensure_timelines_dir_empty(timelines_path: &Path) -> Result<(), DeleteTenantError> {
+async fn ensure_timelines_dir_empty(timelines_path: &Utf8Path) -> Result<(), DeleteTenantError> {
     // Assert timelines dir is empty.
     if !fs_ext::is_directory_empty(timelines_path).await? {
         // Display first 10 items in directory
@@ -188,20 +186,18 @@ async fn cleanup_remaining_fs_traces(
     conf: &PageServerConf,
     tenant_id: &TenantId,
 ) -> Result<(), DeleteTenantError> {
-    let rm = |p: PathBuf, is_dir: bool| async move {
+    let rm = |p: Utf8PathBuf, is_dir: bool| async move {
         if is_dir {
             tokio::fs::remove_dir(&p).await
         } else {
             tokio::fs::remove_file(&p).await
         }
         .or_else(fs_ext::ignore_not_found)
-        .with_context(|| {
-            let to_display = p.display();
-            format!("failed to delete {to_display}")
-        })
+        .with_context(|| format!("failed to delete {p}"))
     };
 
     rm(conf.tenant_config_path(tenant_id), false).await?;
+    rm(conf.tenant_location_config_path(tenant_id), false).await?;
 
     fail::fail_point!("tenant-delete-before-remove-timelines-dir", |_| {
         Err(anyhow::anyhow!(

pageserver/src/tenant/ephemeral_file.rs

@@ -6,11 +6,11 @@ use crate::context::RequestContext;
 use crate::page_cache::{self, PAGE_SZ};
 use crate::tenant::block_io::{BlockCursor, BlockLease, BlockReader};
 use crate::virtual_file::VirtualFile;
+use camino::Utf8PathBuf;
 use std::cmp::min;
 use std::fs::OpenOptions;
 use std::io::{self, ErrorKind};
 use std::ops::DerefMut;
-use std::path::PathBuf;
 use std::sync::atomic::AtomicU64;
 use tracing::*;
 use utils::id::{TenantId, TimelineId};
@@ -40,7 +40,9 @@ impl EphemeralFile {
 
         let filename = conf
             .timeline_path(&tenant_id, &timeline_id)
-            .join(PathBuf::from(format!("ephemeral-{filename_disambiguator}")));
+            .join(Utf8PathBuf::from(format!(
+                "ephemeral-{filename_disambiguator}"
+            )));
 
         let file = VirtualFile::open_with_options(
             &filename,
@@ -62,46 +64,40 @@ impl EphemeralFile {
         self.len
     }
 
-    pub(crate) async fn read_blk(
+    pub(crate) async fn read_blk<'c>(
         &self,
         blknum: u32,
-        ctx: &RequestContext,
-    ) -> Result<BlockLease, io::Error> {
+        ctx: &'c RequestContext,
+    ) -> Result<BlockLease<'c, '_>, io::Error> {
         let flushed_blknums = 0..self.len / PAGE_SZ as u64;
         if flushed_blknums.contains(&(blknum as u64)) {
             let cache = page_cache::get();
-            loop {
-                match cache
-                    .read_immutable_buf(self.page_cache_file_id, blknum, ctx)
-                    .await
-                    .map_err(|e| {
-                        std::io::Error::new(
-                            std::io::ErrorKind::Other,
-                            // order path before error because error is anyhow::Error => might have many contexts
-                            format!(
-                                "ephemeral file: read immutable page #{}: {}: {:#}",
-                                blknum,
-                                self.file.path.display(),
-                                e,
-                            ),
-                        )
-                    })? {
-                    page_cache::ReadBufResult::Found(guard) => {
-                        return Ok(BlockLease::PageReadGuard(guard))
-                    }
-                    page_cache::ReadBufResult::NotFound(mut write_guard) => {
-                        let buf: &mut [u8] = write_guard.deref_mut();
-                        debug_assert_eq!(buf.len(), PAGE_SZ);
-                        self.file
-                            .read_exact_at(&mut buf[..], blknum as u64 * PAGE_SZ as u64)
-                            .await?;
-                        write_guard.mark_valid();
-
-                        // Swap for read lock
-                        continue;
-                    }
-                };
-            }
+            match cache
+                .read_immutable_buf(self.page_cache_file_id, blknum, ctx)
+                .await
+                .map_err(|e| {
+                    std::io::Error::new(
+                        std::io::ErrorKind::Other,
+                        // order path before error because error is anyhow::Error => might have many contexts
+                        format!(
+                            "ephemeral file: read immutable page #{}: {}: {:#}",
+                            blknum, self.file.path, e,
+                        ),
+                    )
+                })? {
+                page_cache::ReadBufResult::Found(guard) => {
+                    return Ok(BlockLease::PageReadGuard(guard))
+                }
+                page_cache::ReadBufResult::NotFound(mut write_guard) => {
+                    let buf: &mut [u8] = write_guard.deref_mut();
+                    debug_assert_eq!(buf.len(), PAGE_SZ);
+                    self.file
+                        .read_exact_at(&mut buf[..], blknum as u64 * PAGE_SZ as u64)
+                        .await?;
+                    let read_guard = write_guard.mark_valid();
+                    return Ok(BlockLease::PageReadGuard(read_guard));
+                }
+            };
         } else {
             debug_assert_eq!(blknum as u64, self.len / PAGE_SZ as u64);
             Ok(BlockLease::EphemeralFileMutableTail(&self.mutable_tail))
@@ -171,7 +167,7 @@ impl EphemeralFile {
                                         let buf: &mut [u8] = write_guard.deref_mut();
                                         debug_assert_eq!(buf.len(), PAGE_SZ);
                                         buf.copy_from_slice(&self.ephemeral_file.mutable_tail);
-                                        write_guard.mark_valid();
+                                        let _ = write_guard.mark_valid();
                                         // pre-warm successful
                                     }
                                     Err(e) => {
@@ -195,7 +191,7 @@ impl EphemeralFile {
                                         "ephemeral_file: write_blob: write-back full tail blk #{}: {:#}: {}",
                                         self.blknum,
                                         e,
-                                        self.ephemeral_file.file.path.display(),
+                                        self.ephemeral_file.file.path,
                                     ),
                                 ));
                             }
@@ -258,8 +254,7 @@ impl Drop for EphemeralFile {
                 // not found files might also be related to https://github.com/neondatabase/neon/issues/2442
                 error!(
                     "could not remove ephemeral file '{}': {}",
-                    self.file.path.display(),
-                    e
+                    self.file.path, e
                 );
             }
         }

pageserver/src/tenant/mgr.rs

@@ -1,10 +1,9 @@
 //! This module acts as a switchboard to access different repositories managed by this
 //! page server.
 
+use camino::{Utf8Path, Utf8PathBuf};
 use rand::{distributions::Alphanumeric, Rng};
 use std::collections::{hash_map, HashMap};
-use std::ffi::OsStr;
-use std::path::{Path, PathBuf};
 use std::sync::Arc;
 use tokio::fs;
 
@@ -25,9 +24,11 @@ use crate::control_plane_client::{
 };
 use crate::deletion_queue::DeletionQueueClient;
 use crate::task_mgr::{self, TaskKind};
-use crate::tenant::config::TenantConfOpt;
+use crate::tenant::config::{LocationConf, LocationMode, TenantConfOpt};
 use crate::tenant::delete::DeleteTenantFlow;
-use crate::tenant::{create_tenant_files, CreateTenantFilesMode, Tenant, TenantState};
+use crate::tenant::{
+    create_tenant_files, AttachedTenantConf, CreateTenantFilesMode, Tenant, TenantState,
+};
 use crate::{InitializationOrder, IGNORED_TENANT_FILE_NAME, TEMP_FILE_SUFFIX};
 
 use utils::crashsafe::path_with_suffix_extension;
@@ -39,6 +40,39 @@ use super::delete::DeleteTenantError;
 use super::timeline::delete::DeleteTimelineFlow;
 use super::TenantSharedResources;
 
+/// For a tenant that appears in TenantsMap, it may either be
+/// - `Attached`: has a full Tenant object, is elegible to service
+///    reads and ingest WAL.
+/// - `Secondary`: is only keeping a local cache warm.
+///
+/// Secondary is a totally distinct state rather than being a mode of a `Tenant`, because
+/// that way we avoid having to carefully switch a tenant's ingestion etc on and off during
+/// its lifetime, and we can preserve some important safety invariants like `Tenant` always
+/// having a properly acquired generation (Secondary doesn't need a generation)
+#[derive(Clone)]
+pub enum TenantSlot {
+    Attached(Arc<Tenant>),
+    Secondary,
+}
+
+impl TenantSlot {
+    /// Return the `Tenant` in this slot if attached, else None
+    fn get_attached(&self) -> Option<&Arc<Tenant>> {
+        match self {
+            Self::Attached(t) => Some(t),
+            Self::Secondary => None,
+        }
+    }
+
+    /// Consume self and return the `Tenant` that was in this slot if attached, else None
+    fn into_attached(self) -> Option<Arc<Tenant>> {
+        match self {
+            Self::Attached(t) => Some(t),
+            Self::Secondary => None,
+        }
+    }
+}
+
 /// The tenants known to the pageserver.
 /// The enum variants are used to distinguish the different states that the pageserver can be in.
 pub(crate) enum TenantsMap {
@@ -46,14 +80,27 @@ pub(crate) enum TenantsMap {
     Initializing,
     /// [`init_tenant_mgr`] is done, all on-disk tenants have been loaded.
     /// New tenants can be added using [`tenant_map_insert`].
-    Open(HashMap<TenantId, Arc<Tenant>>),
+    Open(HashMap<TenantId, TenantSlot>),
     /// The pageserver has entered shutdown mode via [`shutdown_all_tenants`].
     /// Existing tenants are still accessible, but no new tenants can be created.
-    ShuttingDown(HashMap<TenantId, Arc<Tenant>>),
+    ShuttingDown(HashMap<TenantId, TenantSlot>),
 }
 
 impl TenantsMap {
+    /// Convenience function for typical usage, where we want to get a `Tenant` object, for
+    /// working with attached tenants.  If the TenantId is in the map but in Secondary state,
+    /// None is returned.
     pub(crate) fn get(&self, tenant_id: &TenantId) -> Option<&Arc<Tenant>> {
+        match self {
+            TenantsMap::Initializing => None,
+            TenantsMap::Open(m) | TenantsMap::ShuttingDown(m) => {
+                m.get(tenant_id).and_then(TenantSlot::get_attached)
+            }
+        }
+    }
+
+    /// Get the contents of the map at this tenant ID, even if it is in secondary state.
+    pub(crate) fn get_slot(&self, tenant_id: &TenantId) -> Option<&TenantSlot> {
         match self {
             TenantsMap::Initializing => None,
             TenantsMap::Open(m) | TenantsMap::ShuttingDown(m) => m.get(tenant_id),
@@ -62,7 +109,9 @@ impl TenantsMap {
     pub(crate) fn remove(&mut self, tenant_id: &TenantId) -> Option<Arc<Tenant>> {
         match self {
             TenantsMap::Initializing => None,
-            TenantsMap::Open(m) | TenantsMap::ShuttingDown(m) => m.remove(tenant_id),
+            TenantsMap::Open(m) | TenantsMap::ShuttingDown(m) => {
+                m.remove(tenant_id).and_then(TenantSlot::into_attached)
+            }
         }
     }
 }
@@ -73,12 +122,12 @@ impl TenantsMap {
 ///
 /// This is pageserver-specific, as it relies on future processes after a crash to check
 /// for TEMP_FILE_SUFFIX when loading things.
-async fn safe_remove_tenant_dir_all(path: impl AsRef<Path>) -> std::io::Result<()> {
+async fn safe_remove_tenant_dir_all(path: impl AsRef<Utf8Path>) -> std::io::Result<()> {
     let tmp_path = safe_rename_tenant_dir(path).await?;
     fs::remove_dir_all(tmp_path).await
 }
 
-async fn safe_rename_tenant_dir(path: impl AsRef<Path>) -> std::io::Result<PathBuf> {
+async fn safe_rename_tenant_dir(path: impl AsRef<Utf8Path>) -> std::io::Result<Utf8PathBuf> {
     let parent = path
         .as_ref()
         .parent()
@@ -95,7 +144,7 @@ async fn safe_rename_tenant_dir(path: impl AsRef<Path>) -> std::io::Result<PathB
         .collect::<String>()
         + TEMP_FILE_SUFFIX;
     let tmp_path = path_with_suffix_extension(&path, &rand_suffix);
-    fs::rename(&path, &tmp_path).await?;
+    fs::rename(path.as_ref(), &tmp_path).await?;
     fs::File::open(parent).await?.sync_all().await?;
     Ok(tmp_path)
 }
@@ -146,29 +195,25 @@ pub async fn init_tenant_mgr(
         None
     };
 
-    let mut dir_entries = fs::read_dir(&tenants_dir)
-        .await
+    let mut dir_entries = tenants_dir
+        .read_dir_utf8()
         .with_context(|| format!("Failed to list tenants dir {tenants_dir:?}"))?;
 
     let ctx = RequestContext::todo_child(TaskKind::Startup, DownloadBehavior::Warn);
 
     loop {
-        match dir_entries.next_entry().await {
-            Ok(None) => break,
-            Ok(Some(dir_entry)) => {
-                let tenant_dir_path = dir_entry.path();
+        match dir_entries.next() {
+            None => break,
+            Some(Ok(dir_entry)) => {
+                let tenant_dir_path = dir_entry.path().to_path_buf();
                 if crate::is_temporary(&tenant_dir_path) {
-                    info!(
-                        "Found temporary tenant directory, removing: {}",
-                        tenant_dir_path.display()
-                    );
+                    info!("Found temporary tenant directory, removing: {tenant_dir_path}");
                     // No need to use safe_remove_tenant_dir_all because this is already
                     // a temporary path
                     if let Err(e) = fs::remove_dir_all(&tenant_dir_path).await {
                         error!(
                             "Failed to remove temporary directory '{}': {:?}",
-                            tenant_dir_path.display(),
-                            e
+                            tenant_dir_path, e
                         );
                     }
                 } else {
@@ -183,7 +228,7 @@ pub async fn init_tenant_mgr(
                         if let Err(e) = fs::remove_dir(&tenant_dir_path).await {
                             error!(
                                 "Failed to remove empty tenant directory '{}': {e:#}",
-                                tenant_dir_path.display()
+                                tenant_dir_path
                             )
                         }
                         continue;
@@ -197,7 +242,6 @@ pub async fn init_tenant_mgr(
 
                     let tenant_id = match tenant_dir_path
                         .file_name()
-                        .and_then(OsStr::to_str)
                         .unwrap_or_default()
                         .parse::<TenantId>()
                     {
@@ -205,26 +249,65 @@ pub async fn init_tenant_mgr(
                         Err(_) => {
                             warn!(
                                 "Invalid tenant path (garbage in our repo directory?): {}",
-                                tenant_dir_path.display()
+                                tenant_dir_path
                             );
                             continue;
                         }
                     };
 
+                    // Try loading the location configuration
+                    let mut location_conf = match Tenant::load_tenant_config(conf, &tenant_id)
+                        .context("load tenant config")
+                    {
+                        Ok(c) => c,
+                        Err(e) => {
+                            warn!("Marking tenant broken, failed to {e:#}");
+
+                            tenants.insert(
+                                tenant_id,
+                                TenantSlot::Attached(Tenant::create_broken_tenant(
+                                    conf,
+                                    tenant_id,
+                                    "error loading tenant location configuration".to_string(),
+                                )),
+                            );
+
+                            continue;
+                        }
+                    };
+
                     let generation = if let Some(generations) = &tenant_generations {
                         // We have a generation map: treat it as the authority for whether
                         // this tenant is really attached.
                         if let Some(gen) = generations.get(&tenant_id) {
                             *gen
                         } else {
-                            info!("Detaching tenant {tenant_id}, control plane omitted it in re-attach response");
-                            if let Err(e) = safe_remove_tenant_dir_all(&tenant_dir_path).await {
-                                error!(
-                                    "Failed to remove detached tenant directory '{}': {:?}",
-                                    tenant_dir_path.display(),
-                                    e
-                                );
-                            }
+                            match &location_conf.mode {
+                                LocationMode::Secondary(_) => {
+                                    // We do not require the control plane's permission for secondary mode
+                                    // tenants, because they do no remote writes and hence require no
+                                    // generation number
+                                    info!("Loaded tenant {tenant_id} in secondary mode");
+                                    tenants.insert(tenant_id, TenantSlot::Secondary);
+                                }
+                                LocationMode::Attached(_) => {
+                                    // TODO: augment re-attach API to enable the control plane to
+                                    // instruct us about secondary attachments.  That way, instead of throwing
+                                    // away local state, we can gracefully fall back to secondary here, if the control
+                                    // plane tells us so.
+                                    // (https://github.com/neondatabase/neon/issues/5377)
+                                    info!("Detaching tenant {tenant_id}, control plane omitted it in re-attach response");
+                                    if let Err(e) =
+                                        safe_remove_tenant_dir_all(&tenant_dir_path).await
+                                    {
+                                        error!(
+                                            "Failed to remove detached tenant directory '{}': {:?}",
+                                            tenant_dir_path, e
+                                        );
+                                    }
+                                }
+                            };
+
                             continue;
                         }
                     } else {
@@ -232,23 +315,28 @@ pub async fn init_tenant_mgr(
                         // on local disk may activate
                         info!(
                             "Starting tenant {} in legacy mode, no generation",
-                            tenant_dir_path.display()
+                            tenant_dir_path
                         );
                         Generation::none()
                     };
 
+                    // Presence of a generation number implies attachment: attach the tenant
+                    // if it wasn't already, and apply the generation number.
+                    location_conf.attach_in_generation(generation);
+                    Tenant::persist_tenant_config(conf, &tenant_id, &location_conf).await?;
+
                     match schedule_local_tenant_processing(
                         conf,
                         tenant_id,
                         &tenant_dir_path,
-                        generation,
+                        AttachedTenantConf::try_from(location_conf)?,
                         resources.clone(),
                         Some(init_order.clone()),
                         &TENANTS,
                         &ctx,
                     ) {
                         Ok(tenant) => {
-                            tenants.insert(tenant.tenant_id(), tenant);
+                            tenants.insert(tenant.tenant_id(), TenantSlot::Attached(tenant));
                         }
                         Err(e) => {
                             error!("Failed to collect tenant files from dir {tenants_dir:?} for entry {dir_entry:?}, reason: {e:#}");
@@ -256,7 +344,7 @@ pub async fn init_tenant_mgr(
                     }
                 }
             }
-            Err(e) => {
+            Some(Err(e)) => {
                 // On error, print it, but continue with the other tenants. If we error out
                 // here, the pageserver startup fails altogether, causing outage for *all*
                 // tenants. That seems worse.
@@ -279,8 +367,8 @@ pub async fn init_tenant_mgr(
 pub(crate) fn schedule_local_tenant_processing(
     conf: &'static PageServerConf,
     tenant_id: TenantId,
-    tenant_path: &Path,
-    generation: Generation,
+    tenant_path: &Utf8Path,
+    location_conf: AttachedTenantConf,
     resources: TenantSharedResources,
     init_order: Option<InitializationOrder>,
     tenants: &'static tokio::sync::RwLock<TenantsMap>,
@@ -317,7 +405,7 @@ pub(crate) fn schedule_local_tenant_processing(
                 "attaching mark file present but no remote storage configured".to_string(),
             )
         } else {
-            match Tenant::spawn_attach(conf, tenant_id, generation, resources, tenants, ctx) {
+            match Tenant::spawn_attach(conf, tenant_id, resources, location_conf, tenants, ctx) {
                 Ok(tenant) => tenant,
                 Err(e) => {
                     error!("Failed to spawn_attach tenant {tenant_id}, reason: {e:#}");
@@ -329,7 +417,13 @@ pub(crate) fn schedule_local_tenant_processing(
         info!("tenant {tenant_id} is assumed to be loadable, starting load operation");
         // Start loading the tenant into memory. It will initially be in Loading state.
         Tenant::spawn_load(
-            conf, tenant_id, generation, resources, init_order, tenants, ctx,
+            conf,
+            tenant_id,
+            location_conf,
+            resources,
+            init_order,
+            tenants,
+            ctx,
         )
     };
     Ok(tenant)
@@ -385,7 +479,16 @@ async fn shutdown_all_tenants0(tenants: &tokio::sync::RwLock<TenantsMap>) {
 
                 let res = {
                     let (_guard, shutdown_progress) = completion::channel();
-                    tenant.shutdown(shutdown_progress, freeze_and_flush).await
+                    match tenant {
+                        TenantSlot::Attached(t) => {
+                            t.shutdown(shutdown_progress, freeze_and_flush).await
+                        }
+                        TenantSlot::Secondary => {
+                            // TODO: once secondary mode downloads are implemented,
+                            // ensure they have all stopped before we reach this point.
+                            Ok(())
+                        }
+                    }
                 };
 
                 if let Err(other_progress) = res {
@@ -458,16 +561,19 @@ pub async fn create_tenant(
     ctx: &RequestContext,
 ) -> Result<Arc<Tenant>, TenantMapInsertError> {
     tenant_map_insert(tenant_id, || async {
+
+        let location_conf = LocationConf::attached_single(tenant_conf, generation);
+
         // We're holding the tenants lock in write mode while doing local IO.
         // If this section ever becomes contentious, introduce a new `TenantState::Creating`
         // and do the work in that state.
-        let tenant_directory = super::create_tenant_files(conf, tenant_conf, &tenant_id, CreateTenantFilesMode::Create).await?;
+        let tenant_directory = super::create_tenant_files(conf, &location_conf, &tenant_id, CreateTenantFilesMode::Create).await?;
         // TODO: tenant directory remains on disk if we bail out from here on.
         //       See https://github.com/neondatabase/neon/issues/4233
 
         let created_tenant =
             schedule_local_tenant_processing(conf, tenant_id, &tenant_directory,
-                generation, resources, None, &TENANTS, ctx)?;
+                AttachedTenantConf::try_from(location_conf)?, resources, None, &TENANTS, ctx)?;
         // TODO: tenant object & its background loops remain, untracked in tenant map, if we fail here.
         //      See https://github.com/neondatabase/neon/issues/4233
 
@@ -496,20 +602,137 @@ pub async fn set_new_tenant_config(
     info!("configuring tenant {tenant_id}");
     let tenant = get_tenant(tenant_id, true).await?;
 
-    let tenant_config_path = conf.tenant_config_path(&tenant_id);
-    Tenant::persist_tenant_config(&tenant_id, &tenant_config_path, new_tenant_conf)
+    // This is a legacy API that only operates on attached tenants: the preferred
+    // API to use is the location_config/ endpoint, which lets the caller provide
+    // the full LocationConf.
+    let location_conf = LocationConf::attached_single(new_tenant_conf, tenant.generation);
+
+    Tenant::persist_tenant_config(conf, &tenant_id, &location_conf)
         .await
         .map_err(SetNewTenantConfigError::Persist)?;
     tenant.set_new_tenant_config(new_tenant_conf);
     Ok(())
 }
 
+#[instrument(skip_all, fields(tenant_id, new_location_config))]
+pub(crate) async fn upsert_location(
+    conf: &'static PageServerConf,
+    tenant_id: TenantId,
+    new_location_config: LocationConf,
+    broker_client: storage_broker::BrokerClientChannel,
+    remote_storage: Option<GenericRemoteStorage>,
+    deletion_queue_client: DeletionQueueClient,
+    ctx: &RequestContext,
+) -> Result<(), anyhow::Error> {
+    info!("configuring tenant location {tenant_id} to state {new_location_config:?}");
+
+    let mut existing_tenant = match get_tenant(tenant_id, false).await {
+        Ok(t) => Some(t),
+        Err(GetTenantError::NotFound(_)) => None,
+        Err(e) => anyhow::bail!(e),
+    };
+
+    // If we need to shut down a Tenant, do that first
+    let shutdown_tenant = match (&new_location_config.mode, &existing_tenant) {
+        (LocationMode::Secondary(_), Some(t)) => Some(t),
+        (LocationMode::Attached(attach_conf), Some(t)) => {
+            if attach_conf.generation != t.generation {
+                Some(t)
+            } else {
+                None
+            }
+        }
+        _ => None,
+    };
+
+    // TODO: currently we risk concurrent operations interfering with the tenant
+    // while we await shutdown, but we also should not hold the TenantsMap lock
+    // across the whole operation.  Before we start using this function in production,
+    // a follow-on change will revise how concurrency is handled in TenantsMap.
+    // (https://github.com/neondatabase/neon/issues/5378)
+
+    if let Some(tenant) = shutdown_tenant {
+        let (_guard, progress) = utils::completion::channel();
+        info!("Shutting down attached tenant");
+        match tenant.shutdown(progress, false).await {
+            Ok(()) => {}
+            Err(barrier) => {
+                info!("Shutdown already in progress, waiting for it to complete");
+                barrier.wait().await;
+            }
+        }
+        existing_tenant = None;
+    }
+
+    if let Some(tenant) = existing_tenant {
+        // Update the existing tenant
+        Tenant::persist_tenant_config(conf, &tenant_id, &new_location_config)
+            .await
+            .map_err(SetNewTenantConfigError::Persist)?;
+        tenant.set_new_location_config(AttachedTenantConf::try_from(new_location_config)?);
+    } else {
+        // Upsert a fresh TenantSlot into TenantsMap.  Do it within the map write lock,
+        // and re-check that the state of anything we are replacing is as expected.
+        tenant_map_upsert_slot(tenant_id, |old_value| async move {
+            if let Some(TenantSlot::Attached(t)) = old_value {
+                if !matches!(t.current_state(), TenantState::Stopping { .. }) {
+                    anyhow::bail!("Tenant state changed during location configuration update");
+                }
+            }
+
+            let new_slot = match &new_location_config.mode {
+                LocationMode::Secondary(_) => TenantSlot::Secondary,
+                LocationMode::Attached(_attach_config) => {
+                    // Do a schedule_local_tenant_processing
+                    // FIXME: should avoid doing this disk I/O inside the TenantsMap lock,
+                    // we have the same problem in load_tenant/attach_tenant.  Probably
+                    // need a lock in TenantSlot to fix this.
+                    Tenant::persist_tenant_config(conf, &tenant_id, &new_location_config)
+                        .await
+                        .map_err(SetNewTenantConfigError::Persist)?;
+                    let tenant_path = conf.tenant_path(&tenant_id);
+                    let resources = TenantSharedResources {
+                        broker_client,
+                        remote_storage,
+                        deletion_queue_client,
+                    };
+                    let new_tenant = schedule_local_tenant_processing(
+                        conf,
+                        tenant_id,
+                        &tenant_path,
+                        AttachedTenantConf::try_from(new_location_config)?,
+                        resources,
+                        None,
+                        &TENANTS,
+                        ctx,
+                    )
+                    .with_context(|| {
+                        format!("Failed to schedule tenant processing in path {tenant_path:?}")
+                    })?;
+
+                    TenantSlot::Attached(new_tenant)
+                }
+            };
+
+            Ok(new_slot)
+        })
+        .await?;
+    }
+
+    Ok(())
+}
+
 #[derive(Debug, thiserror::Error)]
 pub enum GetTenantError {
     #[error("Tenant {0} not found")]
     NotFound(TenantId),
     #[error("Tenant {0} is not active")]
     NotActive(TenantId),
+    /// Broken is logically a subset of NotActive, but a distinct error is useful as
+    /// NotActive is usually a retryable state for API purposes, whereas Broken
+    /// is a stuck error state
+    #[error("Tenant is broken: {0}")]
+    Broken(String),
 }
 
 /// Gets the tenant from the in-memory data, erroring if it's absent or is not fitting to the query.
@@ -524,10 +747,20 @@ pub async fn get_tenant(
     let tenant = m
         .get(&tenant_id)
         .ok_or(GetTenantError::NotFound(tenant_id))?;
-    if active_only && !tenant.is_active() {
-        Err(GetTenantError::NotActive(tenant_id))
-    } else {
-        Ok(Arc::clone(tenant))
+
+    match tenant.current_state() {
+        TenantState::Broken {
+            reason,
+            backtrace: _,
+        } if active_only => Err(GetTenantError::Broken(reason)),
+        TenantState::Active => Ok(Arc::clone(tenant)),
+        _ => {
+            if active_only {
+                Err(GetTenantError::NotActive(tenant_id))
+            } else {
+                Ok(Arc::clone(tenant))
+            }
+        }
     }
 }
 
@@ -600,7 +833,7 @@ async fn detach_tenant0(
     tenants: &tokio::sync::RwLock<TenantsMap>,
     tenant_id: TenantId,
     detach_ignored: bool,
-) -> Result<PathBuf, TenantStateError> {
+) -> Result<Utf8PathBuf, TenantStateError> {
     let tenant_dir_rename_operation = |tenant_id_to_clean| async move {
         let local_tenant_directory = conf.tenant_path(&tenant_id_to_clean);
         safe_rename_tenant_dir(&local_tenant_directory)
@@ -649,7 +882,12 @@ pub async fn load_tenant(
             remote_storage,
             deletion_queue_client
         };
-        let new_tenant = schedule_local_tenant_processing(conf, tenant_id, &tenant_path, generation, resources, None,  &TENANTS, ctx)
+
+        let mut location_conf = Tenant::load_tenant_config(conf, &tenant_id).map_err( TenantMapInsertError::Other)?;
+        location_conf.attach_in_generation(generation);
+        Tenant::persist_tenant_config(conf, &tenant_id, &location_conf).await?;
+
+        let new_tenant = schedule_local_tenant_processing(conf, tenant_id, &tenant_path, AttachedTenantConf::try_from(location_conf)?, resources, None,  &TENANTS, ctx)
             .with_context(|| {
                 format!("Failed to schedule tenant processing in path {tenant_path:?}")
             })?;
@@ -702,7 +940,10 @@ pub async fn list_tenants() -> Result<Vec<(TenantId, TenantState)>, TenantMapLis
         TenantsMap::Open(m) | TenantsMap::ShuttingDown(m) => m,
     };
     Ok(m.iter()
-        .map(|(id, tenant)| (*id, tenant.current_state()))
+        .filter_map(|(id, tenant)| match tenant {
+            TenantSlot::Attached(tenant) => Some((*id, tenant.current_state())),
+            TenantSlot::Secondary => None,
+        })
         .collect())
 }
 
@@ -719,7 +960,8 @@ pub async fn attach_tenant(
     ctx: &RequestContext,
 ) -> Result<(), TenantMapInsertError> {
     tenant_map_insert(tenant_id, || async {
-        let tenant_dir = create_tenant_files(conf, tenant_conf, &tenant_id, CreateTenantFilesMode::Attach).await?;
+        let location_conf = LocationConf::attached_single(tenant_conf, generation);
+        let tenant_dir = create_tenant_files(conf, &location_conf, &tenant_id, CreateTenantFilesMode::Attach).await?;
         // TODO: tenant directory remains on disk if we bail out from here on.
         //       See https://github.com/neondatabase/neon/issues/4233
 
@@ -730,8 +972,7 @@ pub async fn attach_tenant(
             .context("check for attach marker file existence")?;
         anyhow::ensure!(marker_file_exists, "create_tenant_files should have created the attach marker file");
 
-
-        let attached_tenant = schedule_local_tenant_processing(conf, tenant_id, &tenant_dir, generation, resources, None, &TENANTS, ctx)?;
+        let attached_tenant = schedule_local_tenant_processing(conf, tenant_id, &tenant_dir, AttachedTenantConf::try_from(location_conf)?, resources, None, &TENANTS, ctx)?;
         // TODO: tenant object & its background loops remain, untracked in tenant map, if we fail here.
         //      See https://github.com/neondatabase/neon/issues/4233
 
@@ -754,8 +995,10 @@ pub enum TenantMapInsertError {
     ShuttingDown,
     #[error("tenant {0} already exists, state: {1:?}")]
     TenantAlreadyExists(TenantId, TenantState),
+    #[error("tenant {0} already exists in secondary state")]
+    TenantExistsSecondary(TenantId),
     #[error(transparent)]
-    Closure(#[from] anyhow::Error),
+    Other(#[from] anyhow::Error),
 }
 
 /// Give the given closure access to the tenants map entry for the given `tenant_id`, iff that
@@ -779,20 +1022,47 @@ where
         TenantsMap::Open(m) => m,
     };
     match m.entry(tenant_id) {
-        hash_map::Entry::Occupied(e) => Err(TenantMapInsertError::TenantAlreadyExists(
-            tenant_id,
-            e.get().current_state(),
-        )),
+        hash_map::Entry::Occupied(e) => match e.get() {
+            TenantSlot::Attached(t) => Err(TenantMapInsertError::TenantAlreadyExists(
+                tenant_id,
+                t.current_state(),
+            )),
+            TenantSlot::Secondary => Err(TenantMapInsertError::TenantExistsSecondary(tenant_id)),
+        },
         hash_map::Entry::Vacant(v) => match insert_fn().await {
             Ok(tenant) => {
-                v.insert(tenant.clone());
+                v.insert(TenantSlot::Attached(tenant.clone()));
                 Ok(tenant)
             }
-            Err(e) => Err(TenantMapInsertError::Closure(e)),
+            Err(e) => Err(TenantMapInsertError::Other(e)),
         },
     }
 }
 
+async fn tenant_map_upsert_slot<'a, F, R>(
+    tenant_id: TenantId,
+    upsert_fn: F,
+) -> Result<(), TenantMapInsertError>
+where
+    F: FnOnce(Option<TenantSlot>) -> R,
+    R: std::future::Future<Output = anyhow::Result<TenantSlot>>,
+{
+    let mut guard = TENANTS.write().await;
+    let m = match &mut *guard {
+        TenantsMap::Initializing => return Err(TenantMapInsertError::StillInitializing),
+        TenantsMap::ShuttingDown(_) => return Err(TenantMapInsertError::ShuttingDown),
+        TenantsMap::Open(m) => m,
+    };
+
+    match upsert_fn(m.remove(&tenant_id)).await {
+        Ok(upsert_val) => {
+            m.insert(tenant_id, upsert_val);
+            Ok(())
+        }
+        Err(e) => Err(TenantMapInsertError::Other(e)),
+    }
+}
+
 /// Stops and removes the tenant from memory, if it's not [`TenantState::Stopping`] already, bails otherwise.
 /// Allows to remove other tenant resources manually, via `tenant_cleanup`.
 /// If the cleanup fails, tenant will stay in memory in [`TenantState::Broken`] state, and another removal
@@ -812,28 +1082,40 @@ where
     // tenant-wde cleanup operations may take some time (removing the entire tenant directory), we want to
     // avoid holding the lock for the entire process.
     let tenant = {
-        tenants
+        match tenants
             .write()
             .await
-            .get(&tenant_id)
-            .cloned()
+            .get_slot(&tenant_id)
             .ok_or(TenantStateError::NotFound(tenant_id))?
+        {
+            TenantSlot::Attached(t) => Some(t.clone()),
+            TenantSlot::Secondary => None,
+        }
     };
 
     // allow pageserver shutdown to await for our completion
     let (_guard, progress) = completion::channel();
 
-    // whenever we remove a tenant from memory, we don't want to flush and wait for upload
-    let freeze_and_flush = false;
+    // If the tenant was attached, shut it down gracefully.  For secondary
+    // locations this part is not necessary
+    match tenant {
+        Some(attached_tenant) => {
+            // whenever we remove a tenant from memory, we don't want to flush and wait for upload
+            let freeze_and_flush = false;
 
-    // shutdown is sure to transition tenant to stopping, and wait for all tasks to complete, so
-    // that we can continue safely to cleanup.
-    match tenant.shutdown(progress, freeze_and_flush).await {
-        Ok(()) => {}
-        Err(_other) => {
-            // if pageserver shutdown or other detach/ignore is already ongoing, we don't want to
-            // wait for it but return an error right away because these are distinct requests.
-            return Err(TenantStateError::IsStopping(tenant_id));
+            // shutdown is sure to transition tenant to stopping, and wait for all tasks to complete, so
+            // that we can continue safely to cleanup.
+            match attached_tenant.shutdown(progress, freeze_and_flush).await {
+                Ok(()) => {}
+                Err(_other) => {
+                    // if pageserver shutdown or other detach/ignore is already ongoing, we don't want to
+                    // wait for it but return an error right away because these are distinct requests.
+                    return Err(TenantStateError::IsStopping(tenant_id));
+                }
+            }
+        }
+        None => {
+            // Nothing to wait on when not attached, proceed.
         }
     }
 
@@ -924,6 +1206,8 @@ mod tests {
     use std::sync::Arc;
     use tracing::{info_span, Instrument};
 
+    use crate::tenant::mgr::TenantSlot;
+
     use super::{super::harness::TenantHarness, TenantsMap};
 
     #[tokio::test(start_paused = true)]
@@ -945,7 +1229,7 @@ mod tests {
         // tenant harness configures the logging and we cannot escape it
         let _e = info_span!("testing", tenant_id = %id).entered();
 
-        let tenants = HashMap::from([(id, t.clone())]);
+        let tenants = HashMap::from([(id, TenantSlot::Attached(t.clone()))]);
         let tenants = Arc::new(tokio::sync::RwLock::new(TenantsMap::Open(tenants)));
 
         let (until_cleanup_completed, can_complete_cleanup) = utils::completion::channel();

pageserver/src/tenant/par_fsync.rs

@@ -1,16 +1,17 @@
 use std::{
     io,
-    path::{Path, PathBuf},
     sync::atomic::{AtomicUsize, Ordering},
 };
 
-fn fsync_path(path: &Path) -> io::Result<()> {
+use camino::{Utf8Path, Utf8PathBuf};
+
+fn fsync_path(path: &Utf8Path) -> io::Result<()> {
     // TODO use VirtualFile::fsync_all once we fully go async.
     let file = std::fs::File::open(path)?;
     file.sync_all()
 }
 
-fn parallel_worker(paths: &[PathBuf], next_path_idx: &AtomicUsize) -> io::Result<()> {
+fn parallel_worker(paths: &[Utf8PathBuf], next_path_idx: &AtomicUsize) -> io::Result<()> {
     while let Some(path) = paths.get(next_path_idx.fetch_add(1, Ordering::Relaxed)) {
         fsync_path(path)?;
     }
@@ -18,7 +19,7 @@ fn parallel_worker(paths: &[PathBuf], next_path_idx: &AtomicUsize) -> io::Result
     Ok(())
 }
 
-fn fsync_in_thread_pool(paths: &[PathBuf]) -> io::Result<()> {
+fn fsync_in_thread_pool(paths: &[Utf8PathBuf]) -> io::Result<()> {
     // TODO: remove this function in favor of `par_fsync_async` once we asyncify everything.
 
     /// Use at most this number of threads.
@@ -47,7 +48,7 @@ fn fsync_in_thread_pool(paths: &[PathBuf]) -> io::Result<()> {
 }
 
 /// Parallel fsync all files. Can be used in non-async context as it is using rayon thread pool.
-pub fn par_fsync(paths: &[PathBuf]) -> io::Result<()> {
+pub fn par_fsync(paths: &[Utf8PathBuf]) -> io::Result<()> {
     if paths.len() == 1 {
         fsync_path(&paths[0])?;
         return Ok(());
@@ -58,7 +59,7 @@ pub fn par_fsync(paths: &[PathBuf]) -> io::Result<()> {
 
 /// Parallel fsync asynchronously. If number of files are less than PARALLEL_PATH_THRESHOLD, fsync is done in the current
 /// execution thread. Otherwise, we will spawn_blocking and run it in tokio.
-pub async fn par_fsync_async(paths: &[PathBuf]) -> io::Result<()> {
+pub async fn par_fsync_async(paths: &[Utf8PathBuf]) -> io::Result<()> {
     const MAX_CONCURRENT_FSYNC: usize = 64;
     let mut next = paths.iter().peekable();
     let mut js = tokio::task::JoinSet::new();

pageserver/src/tenant/remote_timeline_client.rs

@@ -209,6 +209,7 @@ pub mod index;
 mod upload;
 
 use anyhow::Context;
+use camino::Utf8Path;
 use chrono::{NaiveDateTime, Utc};
 // re-export these
 pub use download::{is_temp_download_file, list_remote_timelines};
@@ -219,7 +220,6 @@ use utils::backoff::{
 };
 
 use std::collections::{HashMap, VecDeque};
-use std::path::{Path, PathBuf};
 use std::sync::atomic::{AtomicU32, Ordering};
 use std::sync::{Arc, Mutex};
 
@@ -924,7 +924,7 @@ impl RemoteTimelineClient {
             ))?
         });
 
-        let index_file_path = timeline_storage_path.join(Path::new(IndexPart::FILE_NAME));
+        let index_file_path = timeline_storage_path.join(Utf8Path::new(IndexPart::FILE_NAME));
 
         debug!("enqueuing index part deletion");
         self.deletion_queue_client
@@ -1409,7 +1409,7 @@ pub fn remote_timelines_path(tenant_id: &TenantId) -> RemotePath {
 }
 
 pub fn remote_timeline_path(tenant_id: &TenantId, timeline_id: &TimelineId) -> RemotePath {
-    remote_timelines_path(tenant_id).join(&PathBuf::from(timeline_id.to_string()))
+    remote_timelines_path(tenant_id).join(Utf8Path::new(&timeline_id.to_string()))
 }
 
 pub fn remote_layer_path(
@@ -1452,14 +1452,7 @@ pub(crate) fn parse_remote_index_path(path: RemotePath) -> Option<Generation> {
         }
     };
 
-    let file_name_str = match file_name.to_str() {
-        Some(s) => s,
-        None => {
-            tracing::warn!("Malformed index key {:?}", path);
-            return None;
-        }
-    };
-    match file_name_str.split_once('-') {
+    match file_name.split_once('-') {
         Some((_, gen_suffix)) => Generation::parse_suffix(gen_suffix),
         None => None,
     }
@@ -1471,20 +1464,16 @@ pub(crate) fn parse_remote_index_path(path: RemotePath) -> Option<Generation> {
 /// Errors if the path provided does not start from pageserver's workdir.
 pub fn remote_path(
     conf: &PageServerConf,
-    local_path: &Path,
+    local_path: &Utf8Path,
     generation: Generation,
 ) -> anyhow::Result<RemotePath> {
     let stripped = local_path
         .strip_prefix(&conf.workdir)
         .context("Failed to strip workdir prefix")?;
 
-    let suffixed = format!(
-        "{0}{1}",
-        stripped.to_string_lossy(),
-        generation.get_suffix()
-    );
+    let suffixed = format!("{0}{1}", stripped, generation.get_suffix());
 
-    RemotePath::new(&PathBuf::from(suffixed)).with_context(|| {
+    RemotePath::new(Utf8Path::new(&suffixed)).with_context(|| {
         format!(
             "to resolve remote part of path {:?} for base {:?}",
             local_path, conf.workdir
@@ -1504,7 +1493,7 @@ mod tests {
         DEFAULT_PG_VERSION,
     };
 
-    use std::{collections::HashSet, path::Path};
+    use std::collections::HashSet;
     use utils::lsn::Lsn;
 
     pub(super) fn dummy_contents(name: &str) -> Vec<u8> {
@@ -1538,7 +1527,7 @@ mod tests {
         assert_eq!(avec, bvec);
     }
 
-    fn assert_remote_files(expected: &[&str], remote_path: &Path, generation: Generation) {
+    fn assert_remote_files(expected: &[&str], remote_path: &Utf8Path, generation: Generation) {
         let mut expected: Vec<String> = expected
             .iter()
             .map(|x| format!("{}{}", x, generation.get_suffix()))
@@ -1657,12 +1646,12 @@ mod tests {
 
         let timeline_path = harness.timeline_path(&TIMELINE_ID);
 
-        println!("workdir: {}", harness.conf.workdir.display());
+        println!("workdir: {}", harness.conf.workdir);
 
         let remote_timeline_dir = harness
             .remote_fs_dir
             .join(timeline_path.strip_prefix(&harness.conf.workdir).unwrap());
-        println!("remote_timeline_dir: {}", remote_timeline_dir.display());
+        println!("remote_timeline_dir: {remote_timeline_dir}");
 
         let generation = harness.generation;
 
@@ -1909,7 +1898,7 @@ mod tests {
         let index_path = test_state.harness.remote_fs_dir.join(
             remote_index_path(&test_state.harness.tenant_id, &TIMELINE_ID, generation).get_path(),
         );
-        eprintln!("Writing {}", index_path.display());
+        eprintln!("Writing {index_path}");
         std::fs::write(&index_path, index_part_bytes).unwrap();
         example_index_part
     }

pageserver/src/tenant/remote_timeline_client/download.rs

@@ -5,10 +5,10 @@
 
 use std::collections::HashSet;
 use std::future::Future;
-use std::path::Path;
 use std::time::Duration;
 
 use anyhow::{anyhow, Context};
+use camino::Utf8Path;
 use tokio::fs;
 use tokio::io::AsyncWriteExt;
 use tokio_util::sync::CancellationToken;
@@ -74,12 +74,7 @@ pub async fn download_layer_file<'a>(
             // TODO: this doesn't use the cached fd for some reason?
             let mut destination_file = fs::File::create(&temp_file_path)
                 .await
-                .with_context(|| {
-                    format!(
-                        "create a destination file for layer '{}'",
-                        temp_file_path.display()
-                    )
-                })
+                .with_context(|| format!("create a destination file for layer '{temp_file_path}'"))
                 .map_err(DownloadError::Other)?;
             let mut download = storage
                 .download(&remote_path)
@@ -121,7 +116,7 @@ pub async fn download_layer_file<'a>(
     destination_file
         .flush()
         .await
-        .with_context(|| format!("flush source file at {}", temp_file_path.display()))
+        .with_context(|| format!("flush source file at {temp_file_path}"))
         .map_err(DownloadError::Other)?;
 
     let expected = layer_metadata.file_size();
@@ -135,12 +130,7 @@ pub async fn download_layer_file<'a>(
     destination_file
         .sync_all()
         .await
-        .with_context(|| {
-            format!(
-                "failed to fsync source file at {}",
-                temp_file_path.display()
-            )
-        })
+        .with_context(|| format!("failed to fsync source file at {temp_file_path}"))
         .map_err(DownloadError::Other)?;
     drop(destination_file);
 
@@ -152,27 +142,23 @@ pub async fn download_layer_file<'a>(
 
     fs::rename(&temp_file_path, &local_path)
         .await
-        .with_context(|| format!("rename download layer file to {}", local_path.display(),))
+        .with_context(|| format!("rename download layer file to {local_path}"))
         .map_err(DownloadError::Other)?;
 
     crashsafe::fsync_async(&local_path)
         .await
-        .with_context(|| format!("fsync layer file {}", local_path.display(),))
+        .with_context(|| format!("fsync layer file {local_path}"))
         .map_err(DownloadError::Other)?;
 
-    tracing::debug!("download complete: {}", local_path.display());
+    tracing::debug!("download complete: {local_path}");
 
     Ok(bytes_amount)
 }
 
 const TEMP_DOWNLOAD_EXTENSION: &str = "temp_download";
 
-pub fn is_temp_download_file(path: &Path) -> bool {
-    let extension = path.extension().map(|pname| {
-        pname
-            .to_str()
-            .expect("paths passed to this function must be valid Rust strings")
-    });
+pub fn is_temp_download_file(path: &Utf8Path) -> bool {
+    let extension = path.extension();
     match extension {
         Some(TEMP_DOWNLOAD_EXTENSION) => true,
         Some(_) => false,

pageserver/src/tenant/remote_timeline_client/upload.rs

@@ -1,8 +1,9 @@
 //! Helper functions to upload files to remote storage with a RemoteStorage
 
 use anyhow::{bail, Context};
+use camino::Utf8Path;
 use fail::fail_point;
-use std::{io::ErrorKind, path::Path};
+use std::io::ErrorKind;
 use tokio::fs;
 
 use super::Generation;
@@ -50,7 +51,7 @@ pub(super) async fn upload_index_part<'a>(
 pub(super) async fn upload_timeline_layer<'a>(
     conf: &'static PageServerConf,
     storage: &'a GenericRemoteStorage,
-    source_path: &'a Path,
+    source_path: &'a Utf8Path,
     known_metadata: &'a LayerFileMetadata,
     generation: Generation,
 ) -> anyhow::Result<()> {
@@ -68,7 +69,7 @@ pub(super) async fn upload_timeline_layer<'a>(
             // upload. However, a nonexistent file can also be indicative of
             // something worse, like when a file is scheduled for upload before
             // it has been written to disk yet.
-            info!(path = %source_path.display(), "File to upload doesn't exist. Likely the file has been deleted and an upload is not required any more.");
+            info!(path = %source_path, "File to upload doesn't exist. Likely the file has been deleted and an upload is not required any more.");
             return Ok(());
         }
         Err(e) => {
@@ -93,7 +94,7 @@ pub(super) async fn upload_timeline_layer<'a>(
     storage
         .upload(source_file, fs_size, &storage_path, None)
         .await
-        .with_context(|| format!("upload layer from local path '{}'", source_path.display()))?;
+        .with_context(|| format!("upload layer from local path '{source_path}'"))?;
 
     Ok(())
 }

pageserver/src/tenant/storage_layer.rs

@@ -14,6 +14,7 @@ use crate::task_mgr::TaskKind;
 use crate::walrecord::NeonWalRecord;
 use anyhow::Result;
 use bytes::Bytes;
+use camino::Utf8PathBuf;
 use enum_map::EnumMap;
 use enumset::EnumSet;
 use once_cell::sync::Lazy;
@@ -22,7 +23,6 @@ use pageserver_api::models::{
     HistoricLayerInfo, LayerResidenceEvent, LayerResidenceEventReason, LayerResidenceStatus,
 };
 use std::ops::Range;
-use std::path::PathBuf;
 use std::sync::{Arc, Mutex};
 use std::time::{Duration, SystemTime, UNIX_EPOCH};
 use tracing::warn;
@@ -378,7 +378,7 @@ pub trait PersistentLayer: Layer + AsLayerDesc {
 
     // Path to the layer file in the local filesystem.
     // `None` for `RemoteLayer`.
-    fn local_path(&self) -> Option<PathBuf>;
+    fn local_path(&self) -> Option<Utf8PathBuf>;
 
     /// Permanently remove this layer from disk.
     fn delete_resident_layer_file(&self) -> Result<()>;
@@ -456,7 +456,7 @@ pub mod tests {
 /// config. In that case, we use the Path variant to hold the full path to the file on
 /// disk.
 enum PathOrConf {
-    Path(PathBuf),
+    Path(Utf8PathBuf),
     Conf(&'static PageServerConf),
 }
 

pageserver/src/tenant/storage_layer/delta_layer.rs

@@ -41,6 +41,7 @@ use crate::virtual_file::VirtualFile;
 use crate::{walrecord, TEMP_FILE_SUFFIX};
 use crate::{DELTA_FILE_MAGIC, STORAGE_FORMAT_VERSION};
 use anyhow::{bail, ensure, Context, Result};
+use camino::{Utf8Path, Utf8PathBuf};
 use pageserver_api::models::{HistoricLayerInfo, LayerAccessKind};
 use rand::{distributions::Alphanumeric, Rng};
 use serde::{Deserialize, Serialize};
@@ -48,7 +49,6 @@ use std::fs::{self, File};
 use std::io::SeekFrom;
 use std::ops::Range;
 use std::os::unix::fs::FileExt;
-use std::path::{Path, PathBuf};
 use std::sync::Arc;
 use tokio::sync::OnceCell;
 use tracing::*;
@@ -267,7 +267,7 @@ impl PersistentLayer for DeltaLayer {
         Some(self)
     }
 
-    fn local_path(&self) -> Option<PathBuf> {
+    fn local_path(&self) -> Option<Utf8PathBuf> {
         self.local_path()
     }
 
@@ -374,7 +374,7 @@ impl DeltaLayer {
             .await
     }
 
-    pub(crate) fn local_path(&self) -> Option<PathBuf> {
+    pub(crate) fn local_path(&self) -> Option<Utf8PathBuf> {
         Some(self.path())
     }
 
@@ -409,7 +409,7 @@ impl DeltaLayer {
         tenant_id: &TenantId,
         timeline_id: &TimelineId,
         fname: &DeltaFileName,
-    ) -> PathBuf {
+    ) -> Utf8PathBuf {
         match path_or_conf {
             PathOrConf::Path(path) => path.clone(),
             PathOrConf::Conf(conf) => conf
@@ -424,7 +424,7 @@ impl DeltaLayer {
         timeline_id: &TimelineId,
         key_start: Key,
         lsn_range: &Range<Lsn>,
-    ) -> PathBuf {
+    ) -> Utf8PathBuf {
         let rand_string: String = rand::thread_rng()
             .sample_iter(&Alphanumeric)
             .take(8)
@@ -455,7 +455,7 @@ impl DeltaLayer {
         self.inner
             .get_or_try_init(|| self.load_inner(ctx))
             .await
-            .with_context(|| format!("Failed to load delta layer {}", self.path().display()))
+            .with_context(|| format!("Failed to load delta layer {}", self.path()))
     }
 
     async fn load_inner(&self, ctx: &RequestContext) -> Result<Arc<DeltaLayerInner>> {
@@ -471,7 +471,7 @@ impl DeltaLayer {
         if let PathOrConf::Path(ref path) = self.path_or_conf {
             // not production code
 
-            let actual_filename = path.file_name().unwrap().to_str().unwrap().to_owned();
+            let actual_filename = path.file_name().unwrap().to_owned();
             let expected_filename = self.filename().file_name();
 
             if actual_filename != expected_filename {
@@ -510,7 +510,7 @@ impl DeltaLayer {
     /// Create a DeltaLayer struct representing an existing file on disk.
     ///
     /// This variant is only used for debugging purposes, by the 'pagectl' binary.
-    pub fn new_for_path(path: &Path, file: File) -> Result<Self> {
+    pub fn new_for_path(path: &Utf8Path, file: File) -> Result<Self> {
         let mut summary_buf = Vec::new();
         summary_buf.resize(PAGE_SZ, 0);
         file.read_exact_at(&mut summary_buf, 0)?;
@@ -538,7 +538,7 @@ impl DeltaLayer {
         self.desc.delta_file_name()
     }
     /// Path to the layer file in pageserver workdir.
-    pub fn path(&self) -> PathBuf {
+    pub fn path(&self) -> Utf8PathBuf {
         Self::path_for(
             &self.path_or_conf,
             &self.desc.tenant_id,
@@ -549,7 +549,7 @@ impl DeltaLayer {
     /// Loads all keys stored in the layer. Returns key, lsn, value size and value reference.
     ///
     /// The value can be obtained via the [`ValueRef::load`] function.
-    pub(crate) async fn load_keys(&self, ctx: &RequestContext) -> Result<Vec<DeltaEntry<'_>>> {
+    pub(crate) async fn load_keys<'c>(&self, ctx: &RequestContext) -> Result<Vec<DeltaEntry<'_>>> {
         let inner = self
             .load(LayerAccessKind::KeyIter, ctx)
             .await
@@ -573,7 +573,7 @@ impl DeltaLayer {
 ///
 struct DeltaLayerWriterInner {
     conf: &'static PageServerConf,
-    pub path: PathBuf,
+    pub path: Utf8PathBuf,
     timeline_id: TimelineId,
     tenant_id: TenantId,
 
@@ -711,7 +711,7 @@ impl DeltaLayerWriterInner {
         ensure!(
             metadata.len() <= S3_UPLOAD_LIMIT,
             "Created delta layer file at {} of size {} above limit {S3_UPLOAD_LIMIT}!",
-            file.path.display(),
+            file.path,
             metadata.len()
         );
 
@@ -748,7 +748,7 @@ impl DeltaLayerWriterInner {
         );
         std::fs::rename(self.path, &final_path)?;
 
-        trace!("created delta layer {}", final_path.display());
+        trace!("created delta layer {final_path}");
 
         Ok(layer)
     }
@@ -847,13 +847,13 @@ impl Drop for DeltaLayerWriter {
 
 impl DeltaLayerInner {
     pub(super) async fn load(
-        path: &std::path::Path,
+        path: &Utf8Path,
         summary: Option<Summary>,
         ctx: &RequestContext,
     ) -> anyhow::Result<Self> {
         let file = VirtualFile::open(path)
             .await
-            .with_context(|| format!("Failed to open file '{}'", path.display()))?;
+            .with_context(|| format!("Failed to open file '{path}'"))?;
         let file = FileBlockReader::new(file);
 
         let summary_blk = file.read_blk(0, ctx).await?;
@@ -933,15 +933,12 @@ impl DeltaLayerInner {
                 .read_blob_into_buf(pos, &mut buf, ctx)
                 .await
                 .with_context(|| {
-                    format!(
-                        "Failed to read blob from virtual file {}",
-                        file.file.path.display()
-                    )
+                    format!("Failed to read blob from virtual file {}", file.file.path)
                 })?;
             let val = Value::des(&buf).with_context(|| {
                 format!(
                     "Failed to deserialize file blob from virtual file {}",
-                    file.file.path.display()
+                    file.file.path
                 )
             })?;
             match val {
@@ -1041,9 +1038,9 @@ pub struct ValueRef<'a> {
     reader: BlockCursor<'a>,
 }
 
-impl<'a> ValueRef<'a> {
+impl<'c, 'a> ValueRef<'a> {
     /// Loads the value from disk
-    pub async fn load(&self, ctx: &RequestContext) -> Result<Value> {
+    pub async fn load(&self, ctx: &'c RequestContext) -> Result<Value> {
         // theoretically we *could* record an access time for each, but it does not really matter
         let buf = self.reader.read_blob(self.blob_ref.pos(), ctx).await?;
         let val = Value::des(&buf)?;
@@ -1054,11 +1051,11 @@ impl<'a> ValueRef<'a> {
 pub(crate) struct Adapter<T>(T);
 
 impl<T: AsRef<DeltaLayerInner>> Adapter<T> {
-    pub(crate) async fn read_blk(
+    pub(crate) async fn read_blk<'c>(
         &self,
         blknum: u32,
-        ctx: &RequestContext,
-    ) -> Result<BlockLease, std::io::Error> {
+        ctx: &'c RequestContext,
+    ) -> Result<BlockLease<'c, '_>, std::io::Error> {
         self.0.as_ref().file.read_blk(blknum, ctx).await
     }
 }

pageserver/src/tenant/storage_layer/image_layer.rs

@@ -37,6 +37,7 @@ use crate::virtual_file::VirtualFile;
 use crate::{IMAGE_FILE_MAGIC, STORAGE_FORMAT_VERSION, TEMP_FILE_SUFFIX};
 use anyhow::{bail, ensure, Context, Result};
 use bytes::Bytes;
+use camino::{Utf8Path, Utf8PathBuf};
 use hex;
 use pageserver_api::models::{HistoricLayerInfo, LayerAccessKind};
 use rand::{distributions::Alphanumeric, Rng};
@@ -45,7 +46,6 @@ use std::fs::{self, File};
 use std::io::SeekFrom;
 use std::ops::Range;
 use std::os::unix::prelude::FileExt;
-use std::path::{Path, PathBuf};
 use tokio::sync::OnceCell;
 use tracing::*;
 
@@ -195,7 +195,7 @@ impl AsLayerDesc for ImageLayer {
 }
 
 impl PersistentLayer for ImageLayer {
-    fn local_path(&self) -> Option<PathBuf> {
+    fn local_path(&self) -> Option<Utf8PathBuf> {
         self.local_path()
     }
 
@@ -269,10 +269,10 @@ impl ImageLayer {
             .get_value_reconstruct_data(key, reconstruct_state, ctx)
             .await
             // FIXME: makes no sense to dump paths
-            .with_context(|| format!("read {}", self.path().display()))
+            .with_context(|| format!("read {}", self.path()))
     }
 
-    pub(crate) fn local_path(&self) -> Option<PathBuf> {
+    pub(crate) fn local_path(&self) -> Option<Utf8PathBuf> {
         Some(self.path())
     }
 
@@ -304,7 +304,7 @@ impl ImageLayer {
         timeline_id: TimelineId,
         tenant_id: TenantId,
         fname: &ImageFileName,
-    ) -> PathBuf {
+    ) -> Utf8PathBuf {
         match path_or_conf {
             PathOrConf::Path(path) => path.to_path_buf(),
             PathOrConf::Conf(conf) => conf
@@ -318,7 +318,7 @@ impl ImageLayer {
         timeline_id: TimelineId,
         tenant_id: TenantId,
         fname: &ImageFileName,
-    ) -> PathBuf {
+    ) -> Utf8PathBuf {
         let rand_string: String = rand::thread_rng()
             .sample_iter(&Alphanumeric)
             .take(8)
@@ -342,7 +342,7 @@ impl ImageLayer {
         self.inner
             .get_or_try_init(|| self.load_inner(ctx))
             .await
-            .with_context(|| format!("Failed to load image layer {}", self.path().display()))
+            .with_context(|| format!("Failed to load image layer {}", self.path()))
     }
 
     async fn load_inner(&self, ctx: &RequestContext) -> Result<ImageLayerInner> {
@@ -359,7 +359,7 @@ impl ImageLayer {
 
         if let PathOrConf::Path(ref path) = self.path_or_conf {
             // not production code
-            let actual_filename = path.file_name().unwrap().to_str().unwrap().to_owned();
+            let actual_filename = path.file_name().unwrap().to_owned();
             let expected_filename = self.filename().file_name();
 
             if actual_filename != expected_filename {
@@ -399,7 +399,7 @@ impl ImageLayer {
     /// Create an ImageLayer struct representing an existing file on disk.
     ///
     /// This variant is only used for debugging purposes, by the 'pagectl' binary.
-    pub fn new_for_path(path: &Path, file: File) -> Result<ImageLayer> {
+    pub fn new_for_path(path: &Utf8Path, file: File) -> Result<ImageLayer> {
         let mut summary_buf = Vec::new();
         summary_buf.resize(PAGE_SZ, 0);
         file.read_exact_at(&mut summary_buf, 0)?;
@@ -427,7 +427,7 @@ impl ImageLayer {
     }
 
     /// Path to the layer file in pageserver workdir.
-    pub fn path(&self) -> PathBuf {
+    pub fn path(&self) -> Utf8PathBuf {
         Self::path_for(
             &self.path_or_conf,
             self.desc.timeline_id,
@@ -439,14 +439,14 @@ impl ImageLayer {
 
 impl ImageLayerInner {
     pub(super) async fn load(
-        path: &std::path::Path,
+        path: &Utf8Path,
         lsn: Lsn,
         summary: Option<Summary>,
         ctx: &RequestContext,
     ) -> anyhow::Result<Self> {
         let file = VirtualFile::open(path)
             .await
-            .with_context(|| format!("Failed to open file '{}'", path.display()))?;
+            .with_context(|| format!("Failed to open file '{}'", path))?;
         let file = FileBlockReader::new(file);
         let summary_blk = file.read_blk(0, ctx).await?;
         let actual_summary = Summary::des_prefix(summary_blk.as_ref())?;
@@ -526,7 +526,7 @@ impl ImageLayerInner {
 ///
 struct ImageLayerWriterInner {
     conf: &'static PageServerConf,
-    path: PathBuf,
+    path: Utf8PathBuf,
     timeline_id: TimelineId,
     tenant_id: TenantId,
     key_range: Range<Key>,
@@ -558,7 +558,7 @@ impl ImageLayerWriterInner {
                 lsn,
             },
         );
-        info!("new image layer {}", path.display());
+        info!("new image layer {path}");
         let mut file = VirtualFile::open_with_options(
             &path,
             std::fs::OpenOptions::new().write(true).create_new(true),
@@ -685,7 +685,7 @@ impl ImageLayerWriterInner {
         );
         std::fs::rename(self.path, final_path)?;
 
-        trace!("created image layer {}", layer.path().display());
+        trace!("created image layer {}", layer.path());
 
         Ok(layer)
     }

pageserver/src/tenant/storage_layer/remote_layer.rs

@@ -8,9 +8,9 @@ use crate::tenant::remote_timeline_client::index::LayerFileMetadata;
 use crate::tenant::storage_layer::{Layer, ValueReconstructResult, ValueReconstructState};
 use crate::tenant::timeline::layer_manager::LayerManager;
 use anyhow::{bail, Result};
+use camino::Utf8PathBuf;
 use pageserver_api::models::HistoricLayerInfo;
 use std::ops::Range;
-use std::path::PathBuf;
 use std::sync::Arc;
 
 use utils::{
@@ -92,7 +92,7 @@ impl AsLayerDesc for RemoteLayer {
 }
 
 impl PersistentLayer for RemoteLayer {
-    fn local_path(&self) -> Option<PathBuf> {
+    fn local_path(&self) -> Option<Utf8PathBuf> {
         None
     }
 

pageserver/src/tenant/timeline.rs

@@ -9,6 +9,7 @@ mod walreceiver;
 
 use anyhow::{anyhow, bail, ensure, Context, Result};
 use bytes::Bytes;
+use camino::{Utf8Path, Utf8PathBuf};
 use fail::fail_point;
 use futures::StreamExt;
 use itertools::Itertools;
@@ -29,7 +30,6 @@ use utils::id::TenantTimelineId;
 use std::cmp::{max, min, Ordering};
 use std::collections::{BinaryHeap, HashMap, HashSet};
 use std::ops::{Deref, Range};
-use std::path::{Path, PathBuf};
 use std::pin::pin;
 use std::sync::atomic::Ordering as AtomicOrdering;
 use std::sync::{Arc, Mutex, RwLock, Weak};
@@ -56,7 +56,7 @@ use crate::config::PageServerConf;
 use crate::keyspace::{KeyPartitioning, KeySpace, KeySpaceRandomAccum};
 use crate::metrics::{
     TimelineMetrics, MATERIALIZED_PAGE_CACHE_HIT, MATERIALIZED_PAGE_CACHE_HIT_DIRECT,
-    RECONSTRUCT_TIME, UNEXPECTED_ONDEMAND_DOWNLOADS,
+    UNEXPECTED_ONDEMAND_DOWNLOADS,
 };
 use crate::pgdatadir_mapping::LsnForTimestamp;
 use crate::pgdatadir_mapping::{is_rel_fsm_block_key, is_rel_vm_block_key};
@@ -91,12 +91,12 @@ use self::logical_size::LogicalSize;
 use self::walreceiver::{WalReceiver, WalReceiverConf};
 
 use super::config::TenantConf;
-use super::debug_assert_current_span_has_tenant_and_timeline_id;
 use super::remote_timeline_client::index::IndexPart;
 use super::remote_timeline_client::RemoteTimelineClient;
 use super::storage_layer::{
     AsLayerDesc, DeltaLayer, ImageLayer, LayerAccessStatsReset, PersistentLayerDesc,
 };
+use super::{debug_assert_current_span_has_tenant_and_timeline_id, AttachedTenantConf};
 
 #[derive(Debug, PartialEq, Eq, Clone, Copy)]
 pub(super) enum FlushLoopState {
@@ -149,7 +149,7 @@ pub struct TimelineResources {
 
 pub struct Timeline {
     conf: &'static PageServerConf,
-    tenant_conf: Arc<RwLock<TenantConfOpt>>,
+    tenant_conf: Arc<RwLock<AttachedTenantConf>>,
 
     myself: Weak<Self>,
 
@@ -158,6 +158,9 @@ pub struct Timeline {
 
     /// The generation of the tenant that instantiated us: this is used for safety when writing remote objects.
     /// Never changes for the lifetime of this [`Timeline`] object.
+    ///
+    /// This duplicates the generation stored in LocationConf, but that structure is mutable:
+    /// this copy enforces the invariant that generatio doesn't change during a Tenant's lifetime.
     generation: Generation,
 
     pub pg_version: u32,
@@ -496,13 +499,39 @@ impl Timeline {
         };
 
         let timer = crate::metrics::GET_RECONSTRUCT_DATA_TIME.start_timer();
-        self.get_reconstruct_data(key, lsn, &mut reconstruct_state, ctx)
+        let path = self
+            .get_reconstruct_data(key, lsn, &mut reconstruct_state, ctx)
             .await?;
         timer.stop_and_record();
 
-        RECONSTRUCT_TIME
-            .observe_closure_duration(|| self.reconstruct_value(key, lsn, reconstruct_state))
-            .await
+        let start = Instant::now();
+        let res = self.reconstruct_value(key, lsn, reconstruct_state, ctx).await;
+        let elapsed = start.elapsed();
+        crate::metrics::RECONSTRUCT_TIME
+            .for_result(&res)
+            .observe(elapsed.as_secs_f64());
+
+        if cfg!(feature = "testing") && res.is_err() {
+            // it can only be walredo issue
+            use std::fmt::Write;
+
+            let mut msg = String::new();
+
+            path.into_iter().for_each(|(res, cont_lsn, layer)| {
+                writeln!(
+                    msg,
+                    "- layer traversal: result {res:?}, cont_lsn {cont_lsn}, layer: {}",
+                    layer(),
+                )
+                .expect("string grows")
+            });
+
+            // this is to rule out or provide evidence that we could in some cases read a duplicate
+            // walrecord
+            tracing::info!("walredo failed, path:\n{msg}");
+        }
+
+        res
     }
 
     /// Get last or prev record separately. Same as get_last_record_rlsn().last/prev.
@@ -1352,42 +1381,42 @@ const REPARTITION_FREQ_IN_CHECKPOINT_DISTANCE: u64 = 10;
 // Private functions
 impl Timeline {
     fn get_checkpoint_distance(&self) -> u64 {
-        let tenant_conf = self.tenant_conf.read().unwrap();
+        let tenant_conf = self.tenant_conf.read().unwrap().tenant_conf;
         tenant_conf
             .checkpoint_distance
             .unwrap_or(self.conf.default_tenant_conf.checkpoint_distance)
     }
 
     fn get_checkpoint_timeout(&self) -> Duration {
-        let tenant_conf = self.tenant_conf.read().unwrap();
+        let tenant_conf = self.tenant_conf.read().unwrap().tenant_conf;
         tenant_conf
             .checkpoint_timeout
             .unwrap_or(self.conf.default_tenant_conf.checkpoint_timeout)
     }
 
     fn get_compaction_target_size(&self) -> u64 {
-        let tenant_conf = self.tenant_conf.read().unwrap();
+        let tenant_conf = self.tenant_conf.read().unwrap().tenant_conf;
         tenant_conf
             .compaction_target_size
             .unwrap_or(self.conf.default_tenant_conf.compaction_target_size)
     }
 
     fn get_compaction_threshold(&self) -> usize {
-        let tenant_conf = self.tenant_conf.read().unwrap();
+        let tenant_conf = self.tenant_conf.read().unwrap().tenant_conf;
         tenant_conf
             .compaction_threshold
             .unwrap_or(self.conf.default_tenant_conf.compaction_threshold)
     }
 
     fn get_image_creation_threshold(&self) -> usize {
-        let tenant_conf = self.tenant_conf.read().unwrap();
+        let tenant_conf = self.tenant_conf.read().unwrap().tenant_conf;
         tenant_conf
             .image_creation_threshold
             .unwrap_or(self.conf.default_tenant_conf.image_creation_threshold)
     }
 
     fn get_eviction_policy(&self) -> EvictionPolicy {
-        let tenant_conf = self.tenant_conf.read().unwrap();
+        let tenant_conf = self.tenant_conf.read().unwrap().tenant_conf;
         tenant_conf
             .eviction_policy
             .unwrap_or(self.conf.default_tenant_conf.eviction_policy)
@@ -1403,7 +1432,7 @@ impl Timeline {
     }
 
     fn get_gc_feedback(&self) -> bool {
-        let tenant_conf = self.tenant_conf.read().unwrap();
+        let tenant_conf = &self.tenant_conf.read().unwrap().tenant_conf;
         tenant_conf
             .gc_feedback
             .unwrap_or(self.conf.default_tenant_conf.gc_feedback)
@@ -1416,7 +1445,7 @@ impl Timeline {
         // The threshold is embedded in the metric. So, we need to update it.
         {
             let new_threshold = Self::get_evictions_low_residence_duration_metric_threshold(
-                &self.tenant_conf.read().unwrap(),
+                &self.tenant_conf.read().unwrap().tenant_conf,
                 &self.conf.default_tenant_conf,
             );
             let tenant_id_str = self.tenant_id.to_string();
@@ -1435,7 +1464,7 @@ impl Timeline {
     #[allow(clippy::too_many_arguments)]
     pub(super) fn new(
         conf: &'static PageServerConf,
-        tenant_conf: Arc<RwLock<TenantConfOpt>>,
+        tenant_conf: Arc<RwLock<AttachedTenantConf>>,
         metadata: &TimelineMetadata,
         ancestor: Option<Arc<Timeline>>,
         timeline_id: TimelineId,
@@ -1458,7 +1487,7 @@ impl Timeline {
 
         let evictions_low_residence_duration_metric_threshold =
             Self::get_evictions_low_residence_duration_metric_threshold(
-                &tenant_conf_guard,
+                &tenant_conf_guard.tenant_conf,
                 &conf.default_tenant_conf,
             );
         drop(tenant_conf_guard);
@@ -1623,12 +1652,15 @@ impl Timeline {
 
         let tenant_conf_guard = self.tenant_conf.read().unwrap();
         let wal_connect_timeout = tenant_conf_guard
+            .tenant_conf
             .walreceiver_connect_timeout
             .unwrap_or(self.conf.default_tenant_conf.walreceiver_connect_timeout);
         let lagging_wal_timeout = tenant_conf_guard
+            .tenant_conf
             .lagging_wal_timeout
             .unwrap_or(self.conf.default_tenant_conf.lagging_wal_timeout);
         let max_lsn_wal_lag = tenant_conf_guard
+            .tenant_conf
             .max_lsn_wal_lag
             .unwrap_or(self.conf.default_tenant_conf.max_lsn_wal_lag);
         drop(tenant_conf_guard);
@@ -1710,7 +1742,7 @@ impl Timeline {
                         Discovered::Temporary(name) => (name, "temporary timeline file"),
                         Discovered::TemporaryDownload(name) => (name, "temporary download"),
                     };
-                    path.push(name);
+                    path.push(Utf8Path::new(&name));
                     init::cleanup(&path, kind)?;
                     path.pop();
                 }
@@ -2191,10 +2223,10 @@ impl TraversalLayerExt for Arc<dyn PersistentLayer> {
         let timeline_id = self.layer_desc().timeline_id;
         match self.local_path() {
             Some(local_path) => {
-                debug_assert!(local_path.to_str().unwrap().contains(&format!("{}", timeline_id)),
+                debug_assert!(local_path.to_string().contains(&format!("{}", timeline_id)),
                     "need timeline ID to uniquely identify the layer when traversal crosses ancestor boundary",
                 );
-                format!("{}", local_path.display())
+                format!("{local_path}")
             }
             None => {
                 format!("remote {}/{self}", timeline_id)
@@ -2224,7 +2256,7 @@ impl Timeline {
         request_lsn: Lsn,
         reconstruct_state: &mut ValueReconstructState,
         ctx: &RequestContext,
-    ) -> Result<(), PageReconstructError> {
+    ) -> Result<Vec<TraversalPathItem>, PageReconstructError> {
         // Start from the current timeline.
         let mut timeline_owned;
         let mut timeline = self;
@@ -2255,12 +2287,12 @@ impl Timeline {
             // The function should have updated 'state'
             //info!("CALLED for {} at {}: {:?} with {} records, cached {}", key, cont_lsn, result, reconstruct_state.records.len(), cached_lsn);
             match result {
-                ValueReconstructResult::Complete => return Ok(()),
+                ValueReconstructResult::Complete => return Ok(traversal_path),
                 ValueReconstructResult::Continue => {
                     // If we reached an earlier cached page image, we're done.
                     if cont_lsn == cached_lsn + 1 {
                         MATERIALIZED_PAGE_CACHE_HIT.inc_by(1);
-                        return Ok(());
+                        return Ok(traversal_path);
                     }
                     if prev_lsn <= cont_lsn {
                         // Didn't make any progress in last iteration. Error out to avoid
@@ -3696,6 +3728,11 @@ impl Timeline {
             });
 
             writer.as_mut().unwrap().put_value(key, lsn, value).await?;
+
+            if !new_layers.is_empty() {
+                fail_point!("after-timeline-compacted-first-L1");
+            }
+
             prev_key = Some(key);
         }
         if let Some(writer) = writer {
@@ -3717,7 +3754,7 @@ impl Timeline {
                     );
                 }
             }
-            let mut layer_paths: Vec<PathBuf> = new_layers.iter().map(|l| l.path()).collect();
+            let mut layer_paths: Vec<Utf8PathBuf> = new_layers.iter().map(|l| l.path()).collect();
 
             // Fsync all the layer files and directory using multiple threads to
             // minimize latency.
@@ -3827,10 +3864,7 @@ impl Timeline {
             let new_delta_path = l.path();
 
             let metadata = new_delta_path.metadata().with_context(|| {
-                format!(
-                    "read file metadata for new created layer {}",
-                    new_delta_path.display()
-                )
+                format!("read file metadata for new created layer {new_delta_path}")
             })?;
 
             if let Some(remote_client) = &self.remote_client {
@@ -3853,6 +3887,7 @@ impl Timeline {
             );
             let l = l as Arc<dyn PersistentLayer>;
             if guard.contains(&l) {
+                tracing::error!(layer=%l, "duplicated L1 layer");
                 duplicated_layers.insert(l.layer_desc().key());
             } else {
                 if LayerMap::is_l0(l.layer_desc()) {
@@ -4244,6 +4279,7 @@ impl Timeline {
         key: Key,
         request_lsn: Lsn,
         mut data: ValueReconstructState,
+        ctx: &RequestContext,
     ) -> Result<Bytes, PageReconstructError> {
         // Perform WAL redo if needed
         data.records.reverse();
@@ -4307,6 +4343,7 @@ impl Timeline {
                             key,
                             last_rec_lsn,
                             &img,
+                            ctx,
                         )
                         .await
                         .context("Materialized page memoization failed")
@@ -4764,11 +4801,10 @@ fn is_send() {
 
 /// Add a suffix to a layer file's name: .{num}.old
 /// Uses the first available num (starts at 0)
-fn rename_to_backup(path: &Path) -> anyhow::Result<()> {
+fn rename_to_backup(path: &Utf8Path) -> anyhow::Result<()> {
     let filename = path
         .file_name()
-        .ok_or_else(|| anyhow!("Path {} don't have a file name", path.display()))?
-        .to_string_lossy();
+        .ok_or_else(|| anyhow!("Path {path} don't have a file name"))?;
     let mut new_path = path.to_owned();
 
     for i in 0u32.. {

pageserver/src/tenant/timeline/eviction_task.rs

@@ -16,7 +16,7 @@
 use std::{
     collections::HashMap,
     ops::ControlFlow,
-    sync::Arc,
+    sync::{Arc, Mutex},
     time::{Duration, SystemTime},
 };
 
@@ -25,7 +25,7 @@ use tokio_util::sync::CancellationToken;
 use tracing::{debug, error, info, info_span, instrument, warn, Instrument};
 
 use crate::{
-    context::{DownloadBehavior, RequestContext},
+    context::{DownloadBehavior, RequestContext, RequestContextBuilder},
     task_mgr::{self, TaskKind, BACKGROUND_RUNTIME},
     tenant::{
         config::{EvictionPolicy, EvictionPolicyLayerAccessThreshold},
@@ -397,9 +397,14 @@ impl Timeline {
             }
         }
 
+        let permit = crate::page_cache::get().get_permit().await;
+        let ctx = RequestContextBuilder::extend(ctx)
+            .page_cache_permit(permit)
+            .build();
+
         // imitiate repartiting on first compactation
         if let Err(e) = self
-            .collect_keyspace(lsn, ctx)
+            .collect_keyspace(lsn, &ctx)
             .instrument(info_span!("collect_keyspace"))
             .await
         {

pageserver/src/tenant/timeline/init.rs

@@ -12,7 +12,8 @@ use crate::{
     METADATA_FILE_NAME,
 };
 use anyhow::Context;
-use std::{collections::HashMap, ffi::OsString, path::Path, str::FromStr};
+use camino::Utf8Path;
+use std::{collections::HashMap, str::FromStr};
 use utils::lsn::Lsn;
 
 /// Identified files in the timeline directory.
@@ -20,46 +21,43 @@ pub(super) enum Discovered {
     /// The only one we care about
     Layer(LayerFileName, u64),
     /// Old ephmeral files from previous launches, should be removed
-    Ephemeral(OsString),
+    Ephemeral(String),
     /// Old temporary timeline files, unsure what these really are, should be removed
-    Temporary(OsString),
+    Temporary(String),
     /// Temporary on-demand download files, should be removed
-    TemporaryDownload(OsString),
+    TemporaryDownload(String),
     /// "metadata" file we persist locally and include in `index_part.json`
     Metadata,
     /// Backup file from previously future layers
     IgnoredBackup,
     /// Unrecognized, warn about these
-    Unknown(OsString),
+    Unknown(String),
 }
 
 /// Scans the timeline directory for interesting files.
-pub(super) fn scan_timeline_dir(path: &Path) -> anyhow::Result<Vec<Discovered>> {
+pub(super) fn scan_timeline_dir(path: &Utf8Path) -> anyhow::Result<Vec<Discovered>> {
     let mut ret = Vec::new();
 
-    for direntry in std::fs::read_dir(path)? {
+    for direntry in path.read_dir_utf8()? {
         let direntry = direntry?;
-        let direntry_path = direntry.path();
-        let file_name = direntry.file_name();
+        let file_name = direntry.file_name().to_string();
 
-        let fname = file_name.to_string_lossy();
-
-        let discovered = match LayerFileName::from_str(&fname) {
+        let discovered = match LayerFileName::from_str(&file_name) {
             Ok(file_name) => {
                 let file_size = direntry.metadata()?.len();
                 Discovered::Layer(file_name, file_size)
             }
             Err(_) => {
-                if fname == METADATA_FILE_NAME {
+                if file_name == METADATA_FILE_NAME {
                     Discovered::Metadata
-                } else if fname.ends_with(".old") {
+                } else if file_name.ends_with(".old") {
                     // ignore these
                     Discovered::IgnoredBackup
-                } else if remote_timeline_client::is_temp_download_file(&direntry_path) {
+                } else if remote_timeline_client::is_temp_download_file(direntry.path()) {
                     Discovered::TemporaryDownload(file_name)
-                } else if is_ephemeral_file(&fname) {
+                } else if is_ephemeral_file(&file_name) {
                     Discovered::Ephemeral(file_name)
-                } else if is_temporary(&direntry_path) {
+                } else if is_temporary(direntry.path()) {
                     Discovered::Temporary(file_name)
                 } else {
                     Discovered::Unknown(file_name)
@@ -162,15 +160,14 @@ pub(super) fn reconcile(
         .collect::<Vec<_>>()
 }
 
-pub(super) fn cleanup(path: &Path, kind: &str) -> anyhow::Result<()> {
+pub(super) fn cleanup(path: &Utf8Path, kind: &str) -> anyhow::Result<()> {
     let file_name = path.file_name().expect("must be file path");
     tracing::debug!(kind, ?file_name, "cleaning up");
-    std::fs::remove_file(path)
-        .with_context(|| format!("failed to remove {kind} at {}", path.display()))
+    std::fs::remove_file(path).with_context(|| format!("failed to remove {kind} at {path}"))
 }
 
 pub(super) fn cleanup_local_file_for_remote(
-    path: &Path,
+    path: &Utf8Path,
     local: &LayerFileMetadata,
     remote: &LayerFileMetadata,
 ) -> anyhow::Result<()> {
@@ -182,8 +179,7 @@ pub(super) fn cleanup_local_file_for_remote(
     if let Err(err) = crate::tenant::timeline::rename_to_backup(path) {
         assert!(
             path.exists(),
-            "we would leave the local_layer without a file if this does not hold: {}",
-            path.display()
+            "we would leave the local_layer without a file if this does not hold: {path}",
         );
         Err(err)
     } else {
@@ -192,7 +188,7 @@ pub(super) fn cleanup_local_file_for_remote(
 }
 
 pub(super) fn cleanup_future_layer(
-    path: &Path,
+    path: &Utf8Path,
     name: &LayerFileName,
     disk_consistent_lsn: Lsn,
 ) -> anyhow::Result<()> {

pageserver/src/tenant/timeline/uninit.rs

@@ -1,6 +1,7 @@
-use std::{collections::hash_map::Entry, fs, path::PathBuf, sync::Arc};
+use std::{collections::hash_map::Entry, fs, sync::Arc};
 
 use anyhow::Context;
+use camino::Utf8PathBuf;
 use tracing::{error, info, info_span, warn};
 use utils::{crashsafe, fs_ext, id::TimelineId, lsn::Lsn};
 
@@ -155,12 +156,12 @@ pub(crate) fn cleanup_timeline_directory(uninit_mark: TimelineUninitMark) {
 #[must_use]
 pub(crate) struct TimelineUninitMark {
     uninit_mark_deleted: bool,
-    uninit_mark_path: PathBuf,
-    pub(crate) timeline_path: PathBuf,
+    uninit_mark_path: Utf8PathBuf,
+    pub(crate) timeline_path: Utf8PathBuf,
 }
 
 impl TimelineUninitMark {
-    pub(crate) fn new(uninit_mark_path: PathBuf, timeline_path: PathBuf) -> Self {
+    pub(crate) fn new(uninit_mark_path: Utf8PathBuf, timeline_path: Utf8PathBuf) -> Self {
         Self {
             uninit_mark_deleted: false,
             uninit_mark_path,
@@ -197,14 +198,13 @@ impl Drop for TimelineUninitMark {
             if self.timeline_path.exists() {
                 error!(
                     "Uninit mark {} is not removed, timeline {} stays uninitialized",
-                    self.uninit_mark_path.display(),
-                    self.timeline_path.display()
+                    self.uninit_mark_path, self.timeline_path
                 )
             } else {
                 // unblock later timeline creation attempts
                 warn!(
                     "Removing intermediate uninit mark file {}",
-                    self.uninit_mark_path.display()
+                    self.uninit_mark_path
                 );
                 if let Err(e) = self.delete_mark_file_if_present() {
                     error!("Failed to remove the uninit mark file: {e}")

pageserver/src/tenant/upload_queue.rs

@@ -253,7 +253,7 @@ impl std::fmt::Display for UploadOp {
                 write!(f, "UploadMetadata(lsn: {})", lsn)
             }
             UploadOp::Delete(delete) => {
-                write!(f, "Delete({} layers)", delete.layers.len(),)
+                write!(f, "Delete({} layers)", delete.layers.len())
             }
             UploadOp::Barrier(_) => write!(f, "Barrier"),
         }

pageserver/src/trace.rs

@@ -1,8 +1,8 @@
 use bytes::Bytes;
+use camino::Utf8PathBuf;
 use std::{
     fs::{create_dir_all, File},
     io::{BufWriter, Write},
-    path::PathBuf,
 };
 
 pub struct Tracer {
@@ -16,7 +16,7 @@ impl Drop for Tracer {
 }
 
 impl Tracer {
-    pub fn new(path: PathBuf) -> Self {
+    pub fn new(path: Utf8PathBuf) -> Self {
         let parent = path.parent().expect("failed to parse parent path");
         create_dir_all(parent).expect("failed to create trace dir");
 

pageserver/src/virtual_file.rs

@@ -12,11 +12,11 @@
 //!
 use crate::metrics::{StorageIoOperation, STORAGE_IO_SIZE, STORAGE_IO_TIME_METRIC};
 use crate::tenant::TENANTS_SEGMENT_NAME;
+use camino::{Utf8Path, Utf8PathBuf};
 use once_cell::sync::OnceCell;
 use std::fs::{self, File, OpenOptions};
 use std::io::{Error, ErrorKind, Seek, SeekFrom};
 use std::os::unix::fs::FileExt;
-use std::path::{Path, PathBuf};
 use std::sync::atomic::{AtomicBool, AtomicUsize, Ordering};
 use std::sync::{RwLock, RwLockWriteGuard};
 
@@ -51,7 +51,7 @@ pub struct VirtualFile {
     /// if a new file is created, we only pass the create flag when it's initially
     /// opened, in the VirtualFile::create() function, and strip the flag before
     /// storing it here.
-    pub path: PathBuf,
+    pub path: Utf8PathBuf,
     open_options: OpenOptions,
 
     // These are strings becase we only use them for metrics, and those expect strings.
@@ -177,19 +177,19 @@ impl OpenFiles {
 pub enum CrashsafeOverwriteError {
     #[error("final path has no parent dir")]
     FinalPathHasNoParentDir,
-    #[error("remove tempfile: {0}")]
+    #[error("remove tempfile")]
     RemovePreviousTempfile(#[source] std::io::Error),
-    #[error("create tempfile: {0}")]
+    #[error("create tempfile")]
     CreateTempfile(#[source] std::io::Error),
-    #[error("write tempfile: {0}")]
+    #[error("write tempfile")]
     WriteContents(#[source] std::io::Error),
-    #[error("sync tempfile: {0}")]
+    #[error("sync tempfile")]
     SyncTempfile(#[source] std::io::Error),
-    #[error("rename tempfile to final path: {0}")]
+    #[error("rename tempfile to final path")]
     RenameTempfileToFinalPath(#[source] std::io::Error),
-    #[error("open final path parent dir: {0}")]
+    #[error("open final path parent dir")]
     OpenFinalPathParentDir(#[source] std::io::Error),
-    #[error("sync final path parent dir: {0}")]
+    #[error("sync final path parent dir")]
     SyncFinalPathParentDir(#[source] std::io::Error),
 }
 impl CrashsafeOverwriteError {
@@ -210,13 +210,13 @@ impl CrashsafeOverwriteError {
 
 impl VirtualFile {
     /// Open a file in read-only mode. Like File::open.
-    pub async fn open(path: &Path) -> Result<VirtualFile, std::io::Error> {
+    pub async fn open(path: &Utf8Path) -> Result<VirtualFile, std::io::Error> {
         Self::open_with_options(path, OpenOptions::new().read(true)).await
     }
 
     /// Create a new file for writing. If the file exists, it will be truncated.
     /// Like File::create.
-    pub async fn create(path: &Path) -> Result<VirtualFile, std::io::Error> {
+    pub async fn create(path: &Utf8Path) -> Result<VirtualFile, std::io::Error> {
         Self::open_with_options(
             path,
             OpenOptions::new().write(true).create(true).truncate(true),
@@ -230,10 +230,10 @@ impl VirtualFile {
     /// they will be applied also when the file is subsequently re-opened, not only
     /// on the first time. Make sure that's sane!
     pub async fn open_with_options(
-        path: &Path,
+        path: &Utf8Path,
         open_options: &OpenOptions,
     ) -> Result<VirtualFile, std::io::Error> {
-        let path_str = path.to_string_lossy();
+        let path_str = path.to_string();
         let parts = path_str.split('/').collect::<Vec<&str>>();
         let tenant_id;
         let timeline_id;
@@ -281,8 +281,8 @@ impl VirtualFile {
     /// atomic, a crash during the write operation will never leave behind a
     /// partially written file.
     pub async fn crashsafe_overwrite(
-        final_path: &Path,
-        tmp_path: &Path,
+        final_path: &Utf8Path,
+        tmp_path: &Utf8Path,
         content: &[u8],
     ) -> Result<(), CrashsafeOverwriteError> {
         let Some(final_path_parent) = final_path.parent() else {
@@ -544,7 +544,7 @@ impl VirtualFile {
     pub(crate) async fn read_blk(
         &self,
         blknum: u32,
-    ) -> Result<crate::tenant::block_io::BlockLease<'_>, std::io::Error> {
+    ) -> Result<crate::tenant::block_io::BlockLease<'_, '_>, std::io::Error> {
         use crate::page_cache::PAGE_SZ;
         let mut buf = [0; PAGE_SZ];
         self.read_exact_at(&mut buf, blknum as u64 * (PAGE_SZ as u64))
@@ -734,7 +734,7 @@ mod tests {
 
     async fn test_files<OF, FT>(testname: &str, openfunc: OF) -> Result<(), Error>
     where
-        OF: Fn(PathBuf, OpenOptions) -> FT,
+        OF: Fn(Utf8PathBuf, OpenOptions) -> FT,
         FT: Future<Output = Result<MaybeVirtualFile, std::io::Error>>,
     {
         let testdir = crate::config::PageServerConf::test_repo_dir(testname);

pageserver/src/walredo.rs

@@ -38,6 +38,9 @@ use tracing::*;
 use utils::crashsafe::path_with_suffix_extension;
 use utils::{bin_ser::BeSer, id::TenantId, lsn::Lsn, nonblock::set_nonblock};
 
+#[cfg(feature = "testing")]
+use std::sync::atomic::{AtomicUsize, Ordering};
+
 use crate::metrics::{
     WAL_REDO_BYTES_HISTOGRAM, WAL_REDO_RECORDS_HISTOGRAM, WAL_REDO_RECORD_COUNTER, WAL_REDO_TIME,
     WAL_REDO_WAIT_TIME,
@@ -113,6 +116,9 @@ struct ProcessOutput {
 pub struct PostgresRedoManager {
     tenant_id: TenantId,
     conf: &'static PageServerConf,
+    /// Counter to separate same sized walredo inputs failing at the same millisecond.
+    #[cfg(feature = "testing")]
+    dump_sequence: AtomicUsize,
 
     stdout: Mutex<Option<ProcessOutput>>,
     stdin: Mutex<Option<ProcessInput>>,
@@ -224,6 +230,8 @@ impl PostgresRedoManager {
         PostgresRedoManager {
             tenant_id,
             conf,
+            #[cfg(feature = "testing")]
+            dump_sequence: AtomicUsize::default(),
             stdin: Mutex::new(None),
             stdout: Mutex::new(None),
             stderr: Mutex::new(None),
@@ -290,25 +298,27 @@ impl PostgresRedoManager {
             WAL_REDO_BYTES_HISTOGRAM.observe(nbytes as f64);
 
             debug!(
-				"postgres applied {} WAL records ({} bytes) in {} us to reconstruct page image at LSN {}",
-				len,
-				nbytes,
-				duration.as_micros(),
-				lsn
-			);
+                "postgres applied {} WAL records ({} bytes) in {} us to reconstruct page image at LSN {}",
+                len,
+                nbytes,
+                duration.as_micros(),
+                lsn
+            );
 
             // If something went wrong, don't try to reuse the process. Kill it, and
             // next request will launch a new one.
-            if result.is_err() {
+            if let Err(e) = result.as_ref() {
                 error!(
-                "error applying {} WAL records {}..{} ({} bytes) to base image with LSN {} to reconstruct page image at LSN {}",
-                records.len(),
-				records.first().map(|p| p.0).unwrap_or(Lsn(0)),
-				records.last().map(|p| p.0).unwrap_or(Lsn(0)),
-                nbytes,
-				base_img_lsn,
-                lsn
-            );
+                    n_attempts,
+                    "error applying {} WAL records {}..{} ({} bytes) to base image with LSN {} to reconstruct page image at LSN {}: {}",
+                    records.len(),
+                    records.first().map(|p| p.0).unwrap_or(Lsn(0)),
+                    records.last().map(|p| p.0).unwrap_or(Lsn(0)),
+                    nbytes,
+                    base_img_lsn,
+                    lsn,
+                    utils::error::report_compact_sources(e),
+                );
                 // self.stdin only holds stdin & stderr as_raw_fd().
                 // Dropping it as part of take() doesn't close them.
                 // The owning objects (ChildStdout and ChildStderr) are stored in
@@ -325,6 +335,8 @@ impl PostgresRedoManager {
                 if let Some(proc) = self.stdin.lock().unwrap().take() {
                     proc.child.kill_and_wait();
                 }
+            } else if n_attempts != 0 {
+                info!(n_attempts, "retried walredo succeeded");
             }
             n_attempts += 1;
             if n_attempts > MAX_RETRY_ATTEMPTS || result.is_ok() {
@@ -742,7 +754,7 @@ impl PostgresRedoManager {
     #[instrument(skip_all, fields(tenant_id=%self.tenant_id, pid=%input.as_ref().unwrap().child.id()))]
     fn apply_wal_records(
         &self,
-        mut input: MutexGuard<Option<ProcessInput>>,
+        input: MutexGuard<Option<ProcessInput>>,
         tag: BufferTag,
         base_img: &Option<Bytes>,
         records: &[(Lsn, NeonWalRecord)],
@@ -779,6 +791,23 @@ impl PostgresRedoManager {
         build_get_page_msg(tag, &mut writebuf);
         WAL_REDO_RECORD_COUNTER.inc_by(records.len() as u64);
 
+        let res = self.apply_wal_records0(&writebuf, input, wal_redo_timeout);
+
+        if res.is_err() {
+            // not all of these can be caused by this particular input, however these are so rare
+            // in tests so capture all.
+            self.record_and_log(&writebuf);
+        }
+
+        res
+    }
+
+    fn apply_wal_records0(
+        &self,
+        writebuf: &[u8],
+        mut input: MutexGuard<Option<ProcessInput>>,
+        wal_redo_timeout: Duration,
+    ) -> Result<Bytes, std::io::Error> {
         let proc = input.as_mut().unwrap();
         let mut nwrite = 0usize;
         let stdout_fd = proc.stdout_fd;
@@ -984,6 +1013,38 @@ impl PostgresRedoManager {
         }
         Ok(res)
     }
+
+    #[cfg(feature = "testing")]
+    fn record_and_log(&self, writebuf: &[u8]) {
+        let millis = std::time::SystemTime::now()
+            .duration_since(std::time::SystemTime::UNIX_EPOCH)
+            .unwrap()
+            .as_millis();
+
+        let seq = self.dump_sequence.fetch_add(1, Ordering::Relaxed);
+
+        // these files will be collected to an allure report
+        let filename = format!("walredo-{millis}-{}-{seq}.walredo", writebuf.len());
+
+        let path = self.conf.tenant_path(&self.tenant_id).join(&filename);
+
+        let res = std::fs::OpenOptions::new()
+            .write(true)
+            .create_new(true)
+            .read(true)
+            .open(path)
+            .and_then(|mut f| f.write_all(writebuf));
+
+        // trip up allowed_errors
+        if let Err(e) = res {
+            tracing::error!(target=%filename, length=writebuf.len(), "failed to write out the walredo errored input: {e}");
+        } else {
+            tracing::error!(filename, "erroring walredo input saved");
+        }
+    }
+
+    #[cfg(not(feature = "testing"))]
+    fn record_and_log(&self, _: &[u8]) {}
 }
 
 /// Wrapper type around `std::process::Child` which guarantees that the child
@@ -1217,13 +1278,13 @@ mod tests {
 
     struct RedoHarness {
         // underscored because unused, except for removal at drop
-        _repo_dir: tempfile::TempDir,
+        _repo_dir: camino_tempfile::Utf8TempDir,
         manager: PostgresRedoManager,
     }
 
     impl RedoHarness {
         fn new() -> anyhow::Result<Self> {
-            let repo_dir = tempfile::tempdir()?;
+            let repo_dir = camino_tempfile::tempdir()?;
             let conf = PageServerConf::dummy_conf(repo_dir.path().to_path_buf());
             let conf = Box::leak(Box::new(conf));
             let tenant_id = TenantId::generate();

poetry.lock

@@ -2415,18 +2415,18 @@ files = [
 
 [[package]]
 name = "urllib3"
-version = "1.26.11"
+version = "1.26.17"
 description = "HTTP library with thread-safe connection pooling, file post, and more."
 optional = false
-python-versions = ">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*, !=3.4.*, !=3.5.*, <4"
+python-versions = ">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*, !=3.4.*, !=3.5.*"
 files = [
-    {file = "urllib3-1.26.11-py2.py3-none-any.whl", hash = "sha256:c33ccba33c819596124764c23a97d25f32b28433ba0dedeb77d873a38722c9bc"},
-    {file = "urllib3-1.26.11.tar.gz", hash = "sha256:ea6e8fb210b19d950fab93b60c9009226c63a28808bc8386e05301e25883ac0a"},
+    {file = "urllib3-1.26.17-py2.py3-none-any.whl", hash = "sha256:94a757d178c9be92ef5539b8840d48dc9cf1b2709c9d6b588232a055c524458b"},
+    {file = "urllib3-1.26.17.tar.gz", hash = "sha256:24d6a242c28d29af46c3fae832c36db3bbebcc533dd1bb549172cd739c82df21"},
 ]
 
 [package.extras]
-brotli = ["brotli (>=1.0.9)", "brotlicffi (>=0.8.0)", "brotlipy (>=0.6.0)"]
-secure = ["certifi", "cryptography (>=1.3.4)", "idna (>=2.0.0)", "ipaddress", "pyOpenSSL (>=0.14)"]
+brotli = ["brotli (==1.0.9)", "brotli (>=1.0.9)", "brotlicffi (>=0.8.0)", "brotlipy (>=0.6.0)"]
+secure = ["certifi", "cryptography (>=1.3.4)", "idna (>=2.0.0)", "ipaddress", "pyOpenSSL (>=0.14)", "urllib3-secure-extra"]
 socks = ["PySocks (>=1.5.6,!=1.5.7,<2.0)"]
 
 [[package]]
@@ -2648,7 +2648,65 @@ files = [
 docs = ["jaraco.packaging (>=9)", "jaraco.tidelift (>=1.4)", "rst.linker (>=1.9)", "sphinx"]
 testing = ["func-timeout", "jaraco.itertools", "pytest (>=6)", "pytest-black (>=0.3.7)", "pytest-checkdocs (>=2.4)", "pytest-cov", "pytest-enabler (>=1.3)", "pytest-flake8", "pytest-mypy (>=0.9.1)"]
 
+[[package]]
+name = "zstandard"
+version = "0.21.0"
+description = "Zstandard bindings for Python"
+optional = false
+python-versions = ">=3.7"
+files = [
+    {file = "zstandard-0.21.0-cp310-cp310-macosx_10_9_x86_64.whl", hash = "sha256:649a67643257e3b2cff1c0a73130609679a5673bf389564bc6d4b164d822a7ce"},
+    {file = "zstandard-0.21.0-cp310-cp310-macosx_11_0_arm64.whl", hash = "sha256:144a4fe4be2e747bf9c646deab212666e39048faa4372abb6a250dab0f347a29"},
+    {file = "zstandard-0.21.0-cp310-cp310-manylinux_2_17_aarch64.manylinux2014_aarch64.whl", hash = "sha256:b72060402524ab91e075881f6b6b3f37ab715663313030d0ce983da44960a86f"},
+    {file = "zstandard-0.21.0-cp310-cp310-manylinux_2_17_x86_64.manylinux2014_x86_64.whl", hash = "sha256:8257752b97134477fb4e413529edaa04fc0457361d304c1319573de00ba796b1"},
+    {file = "zstandard-0.21.0-cp310-cp310-manylinux_2_5_i686.manylinux1_i686.manylinux_2_12_i686.manylinux2010_i686.whl", hash = "sha256:c053b7c4cbf71cc26808ed67ae955836232f7638444d709bfc302d3e499364fa"},
+    {file = "zstandard-0.21.0-cp310-cp310-manylinux_2_5_i686.manylinux1_i686.manylinux_2_17_i686.manylinux2014_i686.whl", hash = "sha256:2769730c13638e08b7a983b32cb67775650024632cd0476bf1ba0e6360f5ac7d"},
+    {file = "zstandard-0.21.0-cp310-cp310-manylinux_2_5_x86_64.manylinux1_x86_64.manylinux_2_12_x86_64.manylinux2010_x86_64.whl", hash = "sha256:7d3bc4de588b987f3934ca79140e226785d7b5e47e31756761e48644a45a6766"},
+    {file = "zstandard-0.21.0-cp310-cp310-win32.whl", hash = "sha256:67829fdb82e7393ca68e543894cd0581a79243cc4ec74a836c305c70a5943f07"},
+    {file = "zstandard-0.21.0-cp310-cp310-win_amd64.whl", hash = "sha256:e6048a287f8d2d6e8bc67f6b42a766c61923641dd4022b7fd3f7439e17ba5a4d"},
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+    {file = "zstandard-0.21.0-cp311-cp311-manylinux_2_5_i686.manylinux1_i686.manylinux_2_17_i686.manylinux2014_i686.whl", hash = "sha256:df28aa5c241f59a7ab524f8ad8bb75d9a23f7ed9d501b0fed6d40ec3064784e8"},
+    {file = "zstandard-0.21.0-cp311-cp311-win32.whl", hash = "sha256:0aad6090ac164a9d237d096c8af241b8dcd015524ac6dbec1330092dba151657"},
+    {file = "zstandard-0.21.0-cp311-cp311-win_amd64.whl", hash = "sha256:48b6233b5c4cacb7afb0ee6b4f91820afbb6c0e3ae0fa10abbc20000acdf4f11"},
+    {file = "zstandard-0.21.0-cp37-cp37m-macosx_10_9_x86_64.whl", hash = "sha256:e7d560ce14fd209db6adacce8908244503a009c6c39eee0c10f138996cd66d3e"},
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+    {file = "zstandard-0.21.0-cp39-cp39-manylinux_2_5_x86_64.manylinux1_x86_64.manylinux_2_12_x86_64.manylinux2010_x86_64.whl", hash = "sha256:b1367da0dde8ae5040ef0413fb57b5baeac39d8931c70536d5f013b11d3fc3a5"},
+    {file = "zstandard-0.21.0-cp39-cp39-win32.whl", hash = "sha256:db62cbe7a965e68ad2217a056107cc43d41764c66c895be05cf9c8b19578ce9c"},
+    {file = "zstandard-0.21.0-cp39-cp39-win_amd64.whl", hash = "sha256:a8d200617d5c876221304b0e3fe43307adde291b4a897e7b0617a61611dfff6a"},
+    {file = "zstandard-0.21.0.tar.gz", hash = "sha256:f08e3a10d01a247877e4cb61a82a319ea746c356a3786558bed2481e6c405546"},
+]
+
+[package.dependencies]
+cffi = {version = ">=1.11", markers = "platform_python_implementation == \"PyPy\""}
+
+[package.extras]
+cffi = ["cffi (>=1.11)"]
+
 [metadata]
 lock-version = "2.0"
 python-versions = "^3.9"
-content-hash = "c40f62277e788011920f4edb6f7392046ee440f792a104c903097415def9a916"
+content-hash = "c5981d8d7c2deadd47c823bc35f86f830c8e320b653d2d3718bade1f4d2dabca"

proxy/src/bin/pg_sni_router.rs

@@ -168,6 +168,11 @@ async fn task_main(
                     .instrument(tracing::info_span!("handle_client", ?session_id))
                 );
             }
+            Some(Err(e)) = connections.join_next(), if !connections.is_empty() => {
+                if !e.is_panic() && !e.is_cancelled() {
+                    warn!("unexpected error from joined connection task: {e:?}");
+                }
+            }
             _ = cancellation_token.cancelled() => {
                 drop(listener);
                 break;

proxy/src/http/sql_over_http.rs

@@ -45,7 +45,8 @@ enum Payload {
     Batch(BatchQueryData),
 }
 
-const MAX_REQUEST_SIZE: u64 = 1024 * 1024; // 1 MB
+const MAX_RESPONSE_SIZE: usize = 10 * 1024 * 1024; // 10 MiB
+const MAX_REQUEST_SIZE: u64 = 10 * 1024 * 1024; // 10 MiB
 
 static RAW_TEXT_OUTPUT: HeaderName = HeaderName::from_static("neon-raw-text-output");
 static ARRAY_MODE: HeaderName = HeaderName::from_static("neon-array-mode");
@@ -262,6 +263,8 @@ async fn handle_inner(
         None => MAX_REQUEST_SIZE + 1,
     };
 
+    // we don't have a streaming request support yet so this is to prevent OOM
+    // from a malicious user sending an extremely large request body
     if request_content_length > MAX_REQUEST_SIZE {
         return Err(anyhow::anyhow!(
             "request is too large (max is {MAX_REQUEST_SIZE} bytes)"
@@ -384,6 +387,13 @@ async fn query_to_json<T: GenericClient>(
         let row = row?;
         *current_size += row.body_len();
         rows.push(row);
+        // we don't have a streaming response support yet so this is to prevent OOM
+        // from a malicious query (eg a cross join)
+        if *current_size > MAX_RESPONSE_SIZE {
+            return Err(anyhow::anyhow!(
+                "response is too large (max is {MAX_RESPONSE_SIZE} bytes)"
+            ));
+        }
     }
 
     // grab the command tag and number of rows affected

proxy/src/proxy.rs

@@ -130,6 +130,11 @@ pub async fn task_main(
                     }),
                 );
             }
+            Some(Err(e)) = connections.join_next(), if !connections.is_empty() => {
+                if !e.is_panic() && !e.is_cancelled() {
+                    warn!("unexpected error from joined connection task: {e:?}");
+                }
+            }
             _ = cancellation_token.cancelled() => {
                 drop(listener);
                 break;

pyproject.toml

@@ -37,6 +37,7 @@ aiohttp = "3.8.5"
 pytest-rerunfailures = "^11.1.2"
 types-pytest-lazy-fixture = "^0.6.3.3"
 pytest-split = "^0.8.1"
+zstandard = "^0.21.0"
 
 [tool.poetry.group.dev.dependencies]
 black = "^23.3.0"

safekeeper/Cargo.toml

@@ -10,6 +10,8 @@ anyhow.workspace = true
 async-trait.workspace = true
 byteorder.workspace = true
 bytes.workspace = true
+camino.workspace = true
+camino-tempfile.workspace = true
 chrono.workspace = true
 clap = { workspace = true, features = ["derive"] }
 const_format.workspace = true
@@ -36,7 +38,6 @@ tokio = { workspace = true, features = ["fs"] }
 tokio-io-timeout.workspace = true
 tokio-postgres.workspace = true
 toml_edit.workspace = true
-tempfile.workspace = true
 tracing.workspace = true
 url.workspace = true
 metrics.workspace = true

safekeeper/src/bin/safekeeper.rs

@@ -2,6 +2,7 @@
 // Main entry point for the safekeeper executable
 //
 use anyhow::{bail, Context, Result};
+use camino::{Utf8Path, Utf8PathBuf};
 use clap::Parser;
 use futures::future::BoxFuture;
 use futures::stream::FuturesUnordered;
@@ -14,7 +15,6 @@ use toml_edit::Document;
 
 use std::fs::{self, File};
 use std::io::{ErrorKind, Write};
-use std::path::{Path, PathBuf};
 use std::str::FromStr;
 use std::sync::Arc;
 use std::time::Duration;
@@ -63,7 +63,7 @@ split), and serving the hardened part further downstream to pageserver(s).
 struct Args {
     /// Path to the safekeeper data directory.
     #[arg(short = 'D', long, default_value = "./")]
-    datadir: PathBuf,
+    datadir: Utf8PathBuf,
     /// Safekeeper node id.
     #[arg(long)]
     id: Option<u64>,
@@ -92,7 +92,7 @@ struct Args {
     no_sync: bool,
     /// Dump control file at path specified by this argument and exit.
     #[arg(long)]
-    dump_control_file: Option<PathBuf>,
+    dump_control_file: Option<Utf8PathBuf>,
     /// Broker endpoint for storage nodes coordination in the form
     /// http[s]://host:port. In case of https schema TLS is connection is
     /// established; plaintext otherwise.
@@ -128,19 +128,19 @@ struct Args {
     /// validations of JWT tokens. Empty string is allowed and means disabling
     /// auth.
     #[arg(long, verbatim_doc_comment, value_parser = opt_pathbuf_parser)]
-    pg_auth_public_key_path: Option<PathBuf>,
+    pg_auth_public_key_path: Option<Utf8PathBuf>,
     /// If given, enables auth on incoming connections to tenant only WAL
     /// service endpoint (--listen-pg-tenant-only). Value specifies path to a
     /// .pem public key used for validations of JWT tokens. Empty string is
     /// allowed and means disabling auth.
     #[arg(long, verbatim_doc_comment, value_parser = opt_pathbuf_parser)]
-    pg_tenant_only_auth_public_key_path: Option<PathBuf>,
+    pg_tenant_only_auth_public_key_path: Option<Utf8PathBuf>,
     /// If given, enables auth on incoming connections to http management
     /// service endpoint (--listen-http). Value specifies path to a .pem public
     /// key used for validations of JWT tokens. Empty string is allowed and
     /// means disabling auth.
     #[arg(long, verbatim_doc_comment, value_parser = opt_pathbuf_parser)]
-    http_auth_public_key_path: Option<PathBuf>,
+    http_auth_public_key_path: Option<Utf8PathBuf>,
     /// Format for logging, either 'plain' or 'json'.
     #[arg(long, default_value = "plain")]
     log_format: String,
@@ -151,8 +151,8 @@ struct Args {
 }
 
 // Like PathBufValueParser, but allows empty string.
-fn opt_pathbuf_parser(s: &str) -> Result<PathBuf, String> {
-    Ok(PathBuf::from_str(s).unwrap())
+fn opt_pathbuf_parser(s: &str) -> Result<Utf8PathBuf, String> {
+    Ok(Utf8PathBuf::from_str(s).unwrap())
 }
 
 #[tokio::main(flavor = "current_thread")]
@@ -203,7 +203,7 @@ async fn main() -> anyhow::Result<()> {
     info!("version: {GIT_VERSION}");
 
     let args_workdir = &args.datadir;
-    let workdir = args_workdir.canonicalize().with_context(|| {
+    let workdir = args_workdir.canonicalize_utf8().with_context(|| {
         format!("Failed to get the absolute path for input workdir {args_workdir:?}")
     })?;
 
@@ -222,7 +222,7 @@ async fn main() -> anyhow::Result<()> {
             None
         }
         Some(path) => {
-            info!("loading pg auth JWT key from {}", path.display());
+            info!("loading pg auth JWT key from {path}");
             Some(Arc::new(
                 JwtAuth::from_key_path(path).context("failed to load the auth key")?,
             ))
@@ -234,10 +234,7 @@ async fn main() -> anyhow::Result<()> {
             None
         }
         Some(path) => {
-            info!(
-                "loading pg tenant only auth JWT key from {}",
-                path.display()
-            );
+            info!("loading pg tenant only auth JWT key from {path}");
             Some(Arc::new(
                 JwtAuth::from_key_path(path).context("failed to load the auth key")?,
             ))
@@ -249,7 +246,7 @@ async fn main() -> anyhow::Result<()> {
             None
         }
         Some(path) => {
-            info!("loading http auth JWT key from {}", path.display());
+            info!("loading http auth JWT key from {path}");
             Some(Arc::new(
                 JwtAuth::from_key_path(path).context("failed to load the auth key")?,
             ))
@@ -447,7 +444,7 @@ async fn start_safekeeper(conf: SafeKeeperConf) -> Result<()> {
 }
 
 /// Determine safekeeper id.
-fn set_id(workdir: &Path, given_id: Option<NodeId>) -> Result<NodeId> {
+fn set_id(workdir: &Utf8Path, given_id: Option<NodeId>) -> Result<NodeId> {
     let id_file_path = workdir.join(ID_FILE_NAME);
 
     let my_id: NodeId;

safekeeper/src/control_file.rs

@@ -2,12 +2,13 @@
 
 use anyhow::{bail, ensure, Context, Result};
 use byteorder::{LittleEndian, ReadBytesExt, WriteBytesExt};
+use camino::Utf8PathBuf;
 use tokio::fs::{self, File};
 use tokio::io::AsyncWriteExt;
 
 use std::io::Read;
 use std::ops::Deref;
-use std::path::{Path, PathBuf};
+use std::path::Path;
 use std::time::Instant;
 
 use crate::control_file_upgrade::upgrade_control_file;
@@ -39,7 +40,7 @@ pub trait Storage: Deref<Target = SafeKeeperState> {
 #[derive(Debug)]
 pub struct FileStorage {
     // save timeline dir to avoid reconstructing it every time
-    timeline_dir: PathBuf,
+    timeline_dir: Utf8PathBuf,
     conf: SafeKeeperConf,
 
     /// Last state persisted to disk.
@@ -174,7 +175,7 @@ impl Storage for FileStorage {
         let mut control_partial = File::create(&control_partial_path).await.with_context(|| {
             format!(
                 "failed to create partial control file at: {}",
-                &control_partial_path.display()
+                &control_partial_path
             )
         })?;
         let mut buf: Vec<u8> = Vec::new();
@@ -189,13 +190,13 @@ impl Storage for FileStorage {
         control_partial.write_all(&buf).await.with_context(|| {
             format!(
                 "failed to write safekeeper state into control file at: {}",
-                control_partial_path.display()
+                control_partial_path
             )
         })?;
         control_partial.flush().await.with_context(|| {
             format!(
                 "failed to flush safekeeper state into control file at: {}",
-                control_partial_path.display()
+                control_partial_path
             )
         })?;
 
@@ -204,7 +205,7 @@ impl Storage for FileStorage {
             control_partial.sync_all().await.with_context(|| {
                 format!(
                     "failed to sync partial control file at {}",
-                    control_partial_path.display()
+                    control_partial_path
                 )
             })?;
         }
@@ -216,12 +217,10 @@ impl Storage for FileStorage {
         // this sync is not required by any standard but postgres does this (see durable_rename)
         if !self.conf.no_sync {
             let new_f = File::open(&control_path).await?;
-            new_f.sync_all().await.with_context(|| {
-                format!(
-                    "failed to sync control file at: {}",
-                    &control_path.display()
-                )
-            })?;
+            new_f
+                .sync_all()
+                .await
+                .with_context(|| format!("failed to sync control file at: {}", &control_path))?;
 
             // fsync the directory (linux specific)
             let tli_dir = File::open(&self.timeline_dir).await?;
@@ -250,7 +249,7 @@ mod test {
     use utils::{id::TenantTimelineId, lsn::Lsn};
 
     fn stub_conf() -> SafeKeeperConf {
-        let workdir = tempfile::tempdir().unwrap().into_path();
+        let workdir = camino_tempfile::tempdir().unwrap().into_path();
         SafeKeeperConf {
             workdir,
             ..SafeKeeperConf::dummy()

safekeeper/src/debug_dump.rs

@@ -7,6 +7,7 @@ use std::io::Read;
 use std::path::PathBuf;
 
 use anyhow::Result;
+use camino::Utf8Path;
 use chrono::{DateTime, Utc};
 use postgres_ffi::XLogSegNo;
 use serde::Deserialize;
@@ -201,7 +202,7 @@ pub async fn build(args: Args) -> Result<Response> {
 
 /// Builds DiskContent from a directory path. It can fail if the directory
 /// is deleted between the time we get the path and the time we try to open it.
-fn build_disk_content(path: &std::path::Path) -> Result<DiskContent> {
+fn build_disk_content(path: &Utf8Path) -> Result<DiskContent> {
     let mut files = Vec::new();
     for entry in fs::read_dir(path)? {
         if entry.is_err() {
@@ -256,7 +257,7 @@ fn build_file_info(entry: DirEntry) -> Result<FileInfo> {
 fn build_config(config: SafeKeeperConf) -> Config {
     Config {
         id: config.my_id,
-        workdir: config.workdir,
+        workdir: config.workdir.into(),
         listen_pg_addr: config.listen_pg_addr,
         listen_http_addr: config.listen_http_addr,
         no_sync: config.no_sync,

safekeeper/src/lib.rs

@@ -1,8 +1,8 @@
+use camino::Utf8PathBuf;
 use once_cell::sync::Lazy;
 use remote_storage::RemoteStorageConfig;
 use tokio::runtime::Runtime;
 
-use std::path::PathBuf;
 use std::time::Duration;
 use storage_broker::Uri;
 
@@ -51,7 +51,7 @@ pub struct SafeKeeperConf {
     // that during unit testing, because the current directory is global
     // to the process but different unit tests work on different
     // data directories to avoid clashing with each other.
-    pub workdir: PathBuf,
+    pub workdir: Utf8PathBuf,
     pub my_id: NodeId,
     pub listen_pg_addr: String,
     pub listen_pg_addr_tenant_only: Option<String>,
@@ -73,11 +73,11 @@ pub struct SafeKeeperConf {
 }
 
 impl SafeKeeperConf {
-    pub fn tenant_dir(&self, tenant_id: &TenantId) -> PathBuf {
+    pub fn tenant_dir(&self, tenant_id: &TenantId) -> Utf8PathBuf {
         self.workdir.join(tenant_id.to_string())
     }
 
-    pub fn timeline_dir(&self, ttid: &TenantTimelineId) -> PathBuf {
+    pub fn timeline_dir(&self, ttid: &TenantTimelineId) -> Utf8PathBuf {
         self.tenant_dir(&ttid.tenant_id)
             .join(ttid.timeline_id.to_string())
     }
@@ -87,7 +87,7 @@ impl SafeKeeperConf {
     #[cfg(test)]
     fn dummy() -> Self {
         SafeKeeperConf {
-            workdir: PathBuf::from("./"),
+            workdir: Utf8PathBuf::from("./"),
             no_sync: false,
             listen_pg_addr: defaults::DEFAULT_PG_LISTEN_ADDR.to_string(),
             listen_pg_addr_tenant_only: None,

safekeeper/src/pull_timeline.rs

@@ -167,11 +167,11 @@ async fn pull_timeline(status: TimelineStatus, host: String) -> Result<Response>
 
     tokio::fs::create_dir_all(&temp_base).await?;
 
-    let tli_dir = tempfile::Builder::new()
+    let tli_dir = camino_tempfile::Builder::new()
         .suffix("_temptli")
         .prefix(&format!("{}_{}_", ttid.tenant_id, ttid.timeline_id))
         .tempdir_in(temp_base)?;
-    let tli_dir_path = tli_dir.path().to_owned();
+    let tli_dir_path = tli_dir.path().to_path_buf();
 
     // Note: some time happens between fetching list of files and fetching files themselves.
     //       It's possible that some files will be removed from safekeeper and we will fail to fetch them.
@@ -220,9 +220,7 @@ async fn pull_timeline(status: TimelineStatus, host: String) -> Result<Response>
 
     info!(
         "Moving timeline {} from {} to {}",
-        ttid,
-        tli_dir_path.display(),
-        timeline_path.display()
+        ttid, tli_dir_path, timeline_path
     );
     tokio::fs::create_dir_all(conf.tenant_dir(&ttid.tenant_id)).await?;
     tokio::fs::rename(tli_dir_path, &timeline_path).await?;

safekeeper/src/safekeeper.rs

@@ -456,7 +456,7 @@ impl ProposerAcceptorMessage {
 
                 Ok(ProposerAcceptorMessage::AppendRequest(msg))
             }
-            _ => bail!("unknown proposer-acceptor message tag: {}", tag,),
+            _ => bail!("unknown proposer-acceptor message tag: {}", tag),
         }
     }
 }

safekeeper/src/timeline.rs

@@ -2,6 +2,7 @@
 //! to glue together SafeKeeper and all other background services.
 
 use anyhow::{anyhow, bail, Result};
+use camino::Utf8PathBuf;
 use postgres_ffi::XLogSegNo;
 use serde::{Deserialize, Serialize};
 use serde_with::serde_as;
@@ -9,7 +10,6 @@ use tokio::fs;
 
 use serde_with::DisplayFromStr;
 use std::cmp::max;
-use std::path::PathBuf;
 use std::sync::Arc;
 use tokio::sync::{Mutex, MutexGuard};
 use tokio::{
@@ -331,7 +331,7 @@ pub struct Timeline {
     cancellation_rx: watch::Receiver<bool>,
 
     /// Directory where timeline state is stored.
-    pub timeline_dir: PathBuf,
+    pub timeline_dir: Utf8PathBuf,
 }
 
 impl Timeline {
@@ -805,7 +805,7 @@ impl Timeline {
 }
 
 /// Deletes directory and it's contents. Returns false if directory does not exist.
-async fn delete_dir(path: &PathBuf) -> Result<bool> {
+async fn delete_dir(path: &Utf8PathBuf) -> Result<bool> {
     match fs::remove_dir_all(path).await {
         Ok(_) => Ok(true),
         Err(e) if e.kind() == std::io::ErrorKind::NotFound => Ok(false),

safekeeper/src/timelines_global_map.rs

@@ -6,10 +6,10 @@ use crate::safekeeper::ServerInfo;
 use crate::timeline::{Timeline, TimelineError};
 use crate::SafeKeeperConf;
 use anyhow::{bail, Context, Result};
+use camino::Utf8PathBuf;
 use once_cell::sync::Lazy;
 use serde::Serialize;
 use std::collections::HashMap;
-use std::path::PathBuf;
 use std::str::FromStr;
 use std::sync::{Arc, Mutex};
 use tokio::sync::mpsc::Sender;
@@ -89,7 +89,7 @@ impl GlobalTimelines {
         };
         let mut tenant_count = 0;
         for tenants_dir_entry in std::fs::read_dir(&tenants_dir)
-            .with_context(|| format!("failed to list tenants dir {}", tenants_dir.display()))?
+            .with_context(|| format!("failed to list tenants dir {}", tenants_dir))?
         {
             match &tenants_dir_entry {
                 Ok(tenants_dir_entry) => {
@@ -102,9 +102,7 @@ impl GlobalTimelines {
                 }
                 Err(e) => error!(
                     "failed to list tenants dir entry {:?} in directory {}, reason: {:?}",
-                    tenants_dir_entry,
-                    tenants_dir.display(),
-                    e
+                    tenants_dir_entry, tenants_dir, e
                 ),
             }
         }
@@ -136,7 +134,7 @@ impl GlobalTimelines {
 
         let timelines_dir = conf.tenant_dir(&tenant_id);
         for timelines_dir_entry in std::fs::read_dir(&timelines_dir)
-            .with_context(|| format!("failed to list timelines dir {}", timelines_dir.display()))?
+            .with_context(|| format!("failed to list timelines dir {}", timelines_dir))?
         {
             match &timelines_dir_entry {
                 Ok(timeline_dir_entry) => {
@@ -168,9 +166,7 @@ impl GlobalTimelines {
                 }
                 Err(e) => error!(
                     "failed to list timelines dir entry {:?} in directory {}, reason: {:?}",
-                    timelines_dir_entry,
-                    timelines_dir.display(),
-                    e
+                    timelines_dir_entry, timelines_dir, e
                 ),
             }
         }
@@ -421,7 +417,7 @@ pub struct TimelineDeleteForceResult {
 }
 
 /// Deletes directory and it's contents. Returns false if directory does not exist.
-fn delete_dir(path: PathBuf) -> Result<bool> {
+fn delete_dir(path: Utf8PathBuf) -> Result<bool> {
     match std::fs::remove_dir_all(path) {
         Ok(_) => Ok(true),
         Err(e) if e.kind() == std::io::ErrorKind::NotFound => Ok(false),

safekeeper/src/wal_backup.rs

@@ -1,5 +1,6 @@
 use anyhow::{Context, Result};
 
+use camino::{Utf8Path, Utf8PathBuf};
 use futures::stream::FuturesOrdered;
 use futures::StreamExt;
 use tokio::task::JoinHandle;
@@ -7,7 +8,6 @@ use utils::id::NodeId;
 
 use std::cmp::min;
 use std::collections::HashMap;
-use std::path::{Path, PathBuf};
 use std::pin::Pin;
 use std::sync::Arc;
 use std::time::Duration;
@@ -230,8 +230,8 @@ pub async fn wal_backup_launcher_task_main(
 
 struct WalBackupTask {
     timeline: Arc<Timeline>,
-    timeline_dir: PathBuf,
-    workspace_dir: PathBuf,
+    timeline_dir: Utf8PathBuf,
+    workspace_dir: Utf8PathBuf,
     wal_seg_size: usize,
     parallel_jobs: usize,
     commit_lsn_watch_rx: watch::Receiver<Lsn>,
@@ -240,8 +240,8 @@ struct WalBackupTask {
 /// Offload single timeline.
 async fn backup_task_main(
     ttid: TenantTimelineId,
-    timeline_dir: PathBuf,
-    workspace_dir: PathBuf,
+    timeline_dir: Utf8PathBuf,
+    workspace_dir: Utf8PathBuf,
     parallel_jobs: usize,
     mut shutdown_rx: Receiver<()>,
 ) {
@@ -351,8 +351,8 @@ pub async fn backup_lsn_range(
     backup_lsn: &mut Lsn,
     end_lsn: Lsn,
     wal_seg_size: usize,
-    timeline_dir: &Path,
-    workspace_dir: &Path,
+    timeline_dir: &Utf8Path,
+    workspace_dir: &Utf8Path,
     parallel_jobs: usize,
 ) -> Result<()> {
     if parallel_jobs < 1 {
@@ -408,8 +408,8 @@ pub async fn backup_lsn_range(
 
 async fn backup_single_segment(
     seg: &Segment,
-    timeline_dir: &Path,
-    workspace_dir: &Path,
+    timeline_dir: &Utf8Path,
+    workspace_dir: &Utf8Path,
 ) -> Result<Segment> {
     let segment_file_path = seg.file_path(timeline_dir)?;
     let remote_segment_path = segment_file_path
@@ -429,7 +429,7 @@ async fn backup_single_segment(
         BACKUP_ERRORS.inc();
     }
     res?;
-    debug!("Backup of {} done", segment_file_path.display());
+    debug!("Backup of {} done", segment_file_path);
 
     Ok(*seg)
 }
@@ -454,7 +454,7 @@ impl Segment {
         XLogFileName(PG_TLI, self.seg_no, self.size())
     }
 
-    pub fn file_path(self, timeline_dir: &Path) -> Result<PathBuf> {
+    pub fn file_path(self, timeline_dir: &Utf8Path) -> Result<Utf8PathBuf> {
         Ok(timeline_dir.join(self.object_name()))
     }
 
@@ -479,19 +479,22 @@ fn get_segments(start: Lsn, end: Lsn, seg_size: usize) -> Vec<Segment> {
 
 static REMOTE_STORAGE: OnceCell<Option<GenericRemoteStorage>> = OnceCell::new();
 
-async fn backup_object(source_file: &Path, target_file: &RemotePath, size: usize) -> Result<()> {
+async fn backup_object(
+    source_file: &Utf8Path,
+    target_file: &RemotePath,
+    size: usize,
+) -> Result<()> {
     let storage = REMOTE_STORAGE
         .get()
         .expect("failed to get remote storage")
         .as_ref()
         .unwrap();
 
-    let file = tokio::io::BufReader::new(File::open(&source_file).await.with_context(|| {
-        format!(
-            "Failed to open file {} for wal backup",
-            source_file.display()
-        )
-    })?);
+    let file = tokio::io::BufReader::new(
+        File::open(&source_file)
+            .await
+            .with_context(|| format!("Failed to open file {} for wal backup", source_file))?,
+    );
 
     storage
         .upload_storage_object(Box::new(file), size, target_file)

safekeeper/src/wal_storage.rs

@@ -9,13 +9,13 @@
 
 use anyhow::{bail, Context, Result};
 use bytes::Bytes;
+use camino::{Utf8Path, Utf8PathBuf};
 use futures::future::BoxFuture;
 use postgres_ffi::v14::xlog_utils::{IsPartialXLogFileName, IsXLogFileName, XLogFromFileName};
 use postgres_ffi::{dispatch_pgversion, XLogSegNo, PG_TLI};
 use remote_storage::RemotePath;
 use std::cmp::{max, min};
 use std::io::{self, SeekFrom};
-use std::path::{Path, PathBuf};
 use std::pin::Pin;
 use tokio::fs::{self, remove_file, File, OpenOptions};
 use tokio::io::{AsyncRead, AsyncWriteExt};
@@ -72,7 +72,7 @@ pub trait Storage {
 /// When storage is created first time, all LSNs are zeroes and there are no segments on disk.
 pub struct PhysicalStorage {
     metrics: WalStorageMetrics,
-    timeline_dir: PathBuf,
+    timeline_dir: Utf8PathBuf,
     conf: SafeKeeperConf,
 
     /// Size of WAL segment in bytes.
@@ -123,7 +123,7 @@ impl PhysicalStorage {
     /// the disk. Otherwise, all LSNs are set to zero.
     pub fn new(
         ttid: &TenantTimelineId,
-        timeline_dir: PathBuf,
+        timeline_dir: Utf8PathBuf,
         conf: &SafeKeeperConf,
         state: &SafeKeeperState,
     ) -> Result<PhysicalStorage> {
@@ -142,7 +142,11 @@ impl PhysicalStorage {
 
             dispatch_pgversion!(
                 version,
-                pgv::xlog_utils::find_end_of_wal(&timeline_dir, wal_seg_size, state.commit_lsn,)?,
+                pgv::xlog_utils::find_end_of_wal(
+                    timeline_dir.as_std_path(),
+                    wal_seg_size,
+                    state.commit_lsn,
+                )?,
                 bail!("unsupported postgres version: {}", version)
             )
         };
@@ -458,7 +462,7 @@ impl Storage for PhysicalStorage {
 
 /// Remove all WAL segments in timeline_dir that match the given predicate.
 async fn remove_segments_from_disk(
-    timeline_dir: &Path,
+    timeline_dir: &Utf8Path,
     wal_seg_size: usize,
     remove_predicate: impl Fn(XLogSegNo) -> bool,
 ) -> Result<()> {
@@ -497,8 +501,8 @@ async fn remove_segments_from_disk(
 }
 
 pub struct WalReader {
-    workdir: PathBuf,
-    timeline_dir: PathBuf,
+    workdir: Utf8PathBuf,
+    timeline_dir: Utf8PathBuf,
     wal_seg_size: usize,
     pos: Lsn,
     wal_segment: Option<Pin<Box<dyn AsyncRead + Send + Sync>>>,
@@ -519,8 +523,8 @@ pub struct WalReader {
 
 impl WalReader {
     pub fn new(
-        workdir: PathBuf,
-        timeline_dir: PathBuf,
+        workdir: Utf8PathBuf,
+        timeline_dir: Utf8PathBuf,
         state: &SafeKeeperState,
         start_pos: Lsn,
         enable_remote_read: bool,
@@ -687,7 +691,7 @@ impl WalReader {
     }
 
     /// Helper function for opening a wal file.
-    async fn open_wal_file(wal_file_path: &Path) -> Result<tokio::fs::File> {
+    async fn open_wal_file(wal_file_path: &Utf8Path) -> Result<tokio::fs::File> {
         // First try to open the .partial file.
         let mut partial_path = wal_file_path.to_owned();
         partial_path.set_extension("partial");
@@ -722,10 +726,10 @@ async fn write_zeroes(file: &mut File, mut count: usize) -> Result<()> {
 
 /// Helper returning full path to WAL segment file and its .partial brother.
 fn wal_file_paths(
-    timeline_dir: &Path,
+    timeline_dir: &Utf8Path,
     segno: XLogSegNo,
     wal_seg_size: usize,
-) -> Result<(PathBuf, PathBuf)> {
+) -> Result<(Utf8PathBuf, Utf8PathBuf)> {
     let wal_file_name = XLogFileName(PG_TLI, segno, wal_seg_size);
     let wal_file_path = timeline_dir.join(wal_file_name.clone());
     let wal_file_partial_path = timeline_dir.join(wal_file_name + ".partial");

test_runner/fixtures/neon_fixtures.py

@@ -37,6 +37,7 @@ from psycopg2.extensions import connection as PgConnection
 from psycopg2.extensions import cursor as PgCursor
 from psycopg2.extensions import make_dsn, parse_dsn
 from typing_extensions import Literal
+from urllib3.util.retry import Retry
 
 from fixtures.broker import NeonBroker
 from fixtures.log_helper import log
@@ -1651,11 +1652,14 @@ class NeonPageserver(PgProtocol):
         if '"testing"' not in self.version:
             pytest.skip("pageserver was built without 'testing' feature")
 
-    def http_client(self, auth_token: Optional[str] = None) -> PageserverHttpClient:
+    def http_client(
+        self, auth_token: Optional[str] = None, retries: Optional[Retry] = None
+    ) -> PageserverHttpClient:
         return PageserverHttpClient(
             port=self.service_port.http,
             auth_token=auth_token,
             is_testing_enabled_or_skip=self.is_testing_enabled_or_skip,
+            retries=retries,
         )
 
     @property

test_runner/fixtures/pageserver/http.py

@@ -7,6 +7,8 @@ from dataclasses import dataclass
 from typing import Any, Dict, List, Optional, Tuple
 
 import requests
+from requests.adapters import HTTPAdapter
+from urllib3.util.retry import Retry
 
 from fixtures.log_helper import log
 from fixtures.metrics import Metrics, parse_metrics
@@ -113,12 +115,40 @@ class TenantConfig:
 
 
 class PageserverHttpClient(requests.Session):
-    def __init__(self, port: int, is_testing_enabled_or_skip: Fn, auth_token: Optional[str] = None):
+    def __init__(
+        self,
+        port: int,
+        is_testing_enabled_or_skip: Fn,
+        auth_token: Optional[str] = None,
+        retries: Optional[Retry] = None,
+    ):
         super().__init__()
         self.port = port
         self.auth_token = auth_token
         self.is_testing_enabled_or_skip = is_testing_enabled_or_skip
 
+        if retries is None:
+            # We apply a retry policy that is different to the default `requests` behavior,
+            # because the pageserver has various transiently unavailable states that benefit
+            # from a client retrying on 503
+
+            retries = Retry(
+                # Status retries are for retrying on 503 while e.g. waiting for tenants to activate
+                status=5,
+                # Connection retries are for waiting for the pageserver to come up and listen
+                connect=5,
+                # No read retries: if a request hangs that is not expected behavior
+                # (this may change in future if we do fault injection of a kind that causes
+                #  requests TCP flows to stick)
+                read=False,
+                backoff_factor=0,
+                status_forcelist=[503],
+                allowed_methods=None,
+                remove_headers_on_redirect=[],
+            )
+
+        self.mount("http://", HTTPAdapter(max_retries=retries))
+
         if auth_token is not None:
             self.headers["Authorization"] = f"Bearer {auth_token}"
 

test_runner/fixtures/utils.py

@@ -3,7 +3,6 @@ import json
 import os
 import re
 import subprocess
-import tarfile
 import threading
 import time
 from pathlib import Path
@@ -11,6 +10,7 @@ from typing import TYPE_CHECKING, Any, Callable, Dict, List, Optional, Tuple, Ty
 from urllib.parse import urlencode
 
 import allure
+import zstandard
 from psycopg2.extensions import cursor
 
 from fixtures.log_helper import log
@@ -222,7 +222,7 @@ def get_scale_for_db(size_mb: int) -> int:
 
 
 ATTACHMENT_NAME_REGEX: re.Pattern = re.compile(  # type: ignore[type-arg]
-    r"regression\.diffs|.+\.(?:log|stderr|stdout|filediff|metrics|html)"
+    r"regression\.diffs|.+\.(?:log|stderr|stdout|filediff|metrics|html|walredo)"
 )
 
 
@@ -231,25 +231,35 @@ def allure_attach_from_dir(dir: Path):
 
     for attachment in Path(dir).glob("**/*"):
         if ATTACHMENT_NAME_REGEX.fullmatch(attachment.name) and attachment.stat().st_size > 0:
-            source = str(attachment)
             name = str(attachment.relative_to(dir))
 
-            # compress files larger than 1Mb, they're hardly readable in a browser
-            if attachment.stat().st_size > 1024 * 1024:
-                source = f"{attachment}.tar.gz"
-                with tarfile.open(source, "w:gz") as tar:
-                    tar.add(attachment, arcname=attachment.name)
-                name = f"{name}.tar.gz"
+            # compress files that are larger than 1Mb, they're hardly readable in a browser
+            if attachment.stat().st_size > 1024**2:
+                compressed = attachment.with_suffix(".zst")
 
-            if source.endswith(".tar.gz"):
+                cctx = zstandard.ZstdCompressor()
+                with attachment.open("rb") as fin, compressed.open("wb") as fout:
+                    cctx.copy_stream(fin, fout)
+
+                name = f"{name}.zst"
+                attachment = compressed
+
+            source = str(attachment)
+            if source.endswith(".gz"):
                 attachment_type = "application/gzip"
-                extension = "tar.gz"
+                extension = "gz"
+            elif source.endswith(".zst"):
+                attachment_type = "application/zstd"
+                extension = "zst"
             elif source.endswith(".svg"):
                 attachment_type = "image/svg+xml"
                 extension = "svg"
             elif source.endswith(".html"):
                 attachment_type = "text/html"
                 extension = "html"
+            elif source.endswith(".walredo"):
+                attachment_type = "application/octet-stream"
+                extension = "walredo"
             else:
                 attachment_type = "text/plain"
                 extension = attachment.suffix.removeprefix(".")

test_runner/regress/test_duplicate_layers.py

@@ -1,19 +1,21 @@
 import time
 
 import pytest
-from fixtures.neon_fixtures import NeonEnvBuilder, PgBin
+from fixtures.log_helper import log
+from fixtures.neon_fixtures import NeonEnvBuilder, PgBin, wait_for_last_flush_lsn
+from fixtures.pageserver.utils import wait_for_upload_queue_empty
+from fixtures.remote_storage import LocalFsStorage, RemoteStorageKind
+from requests.exceptions import ConnectionError
 
 
-# Test duplicate layer detection
-#
-# This test sets fail point at the end of first compaction phase:
-# after flushing new L1 layers but before deletion of L0 layers
-# it should cause generation of duplicate L1 layer by compaction after restart.
-@pytest.mark.timeout(600)
 def test_duplicate_layers(neon_env_builder: NeonEnvBuilder, pg_bin: PgBin):
     env = neon_env_builder.init_start()
     pageserver_http = env.pageserver.http_client()
 
+    # use a failpoint to return all L0s as L1s
+    message = ".*duplicated L1 layer layer=.*"
+    env.pageserver.allowed_errors.append(message)
+
     # Use aggressive compaction and checkpoint settings
     tenant_id, _ = env.neon_cli.create_tenant(
         conf={
@@ -33,4 +35,100 @@ def test_duplicate_layers(neon_env_builder: NeonEnvBuilder, pg_bin: PgBin):
     time.sleep(10)  # let compaction to be performed
     assert env.pageserver.log_contains("compact-level0-phase1-return-same")
 
-    pg_bin.run_capture(["pgbench", "-P1", "-N", "-c5", "-T200", "-Mprepared", connstr])
+
+def test_actually_duplicated_l1(neon_env_builder: NeonEnvBuilder, pg_bin: PgBin):
+    """
+    This test sets fail point at the end of first compaction phase:
+    after flushing new L1 layers but before deletion of L0 layers
+    it should cause generation of duplicate L1 layer by compaction after restart.
+    """
+    neon_env_builder.enable_pageserver_remote_storage(RemoteStorageKind.LOCAL_FS)
+
+    env = neon_env_builder.init_start(
+        initial_tenant_conf={
+            "checkpoint_distance": f"{1024 ** 2}",
+            "compaction_target_size": f"{1024 ** 2}",
+            "compaction_period": "0 s",
+            "compaction_threshold": "3",
+        }
+    )
+    pageserver_http = env.pageserver.http_client()
+
+    tenant_id, timeline_id = env.initial_tenant, env.initial_timeline
+
+    pageserver_http.configure_failpoints(("after-timeline-compacted-first-L1", "exit"))
+
+    endpoint = env.endpoints.create_start("main", tenant_id=tenant_id)
+    connstr = endpoint.connstr(options="-csynchronous_commit=off")
+    pg_bin.run_capture(["pgbench", "-i", "-s1", connstr])
+
+    wait_for_last_flush_lsn(env, endpoint, tenant_id, timeline_id)
+
+    # make sure we receive no new wal after this, so that we'll write over the same L1 file.
+    endpoint.stop()
+    for sk in env.safekeepers:
+        sk.stop()
+
+    # hit the exit failpoint
+    with pytest.raises(ConnectionError, match="Remote end closed connection without response"):
+        pageserver_http.timeline_compact(tenant_id, timeline_id)
+    env.pageserver.stop()
+
+    # now the duplicate L1 has been created, but is not yet uploaded
+    assert isinstance(env.pageserver_remote_storage, LocalFsStorage)
+
+    # path = env.remote_storage.timeline_path(tenant_id, timeline_id)
+    l1_found = None
+    for path in env.pageserver.timeline_dir(tenant_id, timeline_id).iterdir():
+        if path.name == "metadata" or path.name.startswith("ephemeral-"):
+            continue
+
+        if len(path.suffixes) > 0:
+            # temp files
+            continue
+
+        [key_range, lsn_range] = path.name.split("__", maxsplit=1)
+
+        if "-" not in lsn_range:
+            # image layer
+            continue
+
+        [key_start, key_end] = key_range.split("-", maxsplit=1)
+
+        if key_start == "0" * 36 and key_end == "F" * 36:
+            # L0
+            continue
+
+        if l1_found is not None:
+            raise RuntimeError(f"found multiple L1: {l1_found.name} and {path.name}")
+        l1_found = path
+
+    assert l1_found is not None, "failed to find L1 locally"
+    original_created_at = l1_found.stat()[8]
+
+    uploaded = env.pageserver_remote_storage.timeline_path(tenant_id, timeline_id) / l1_found.name
+    assert not uploaded.exists(), "to-be-overwritten should not yet be uploaded"
+
+    # give room for fs timestamps
+    time.sleep(1)
+
+    env.pageserver.start()
+    message = f".*duplicated L1 layer layer={l1_found.name}"
+    env.pageserver.allowed_errors.append(message)
+
+    pageserver_http.timeline_compact(tenant_id, timeline_id)
+    # give time for log flush
+    time.sleep(1)
+
+    found_msg = env.pageserver.log_contains(message)
+    assert found_msg is not None, "no layer was duplicated, has this been fixed already?"
+
+    log.info(f"found log line: {found_msg}")
+
+    overwritten_at = l1_found.stat()[8]
+    assert original_created_at < overwritten_at, "expected the L1 to be overwritten"
+
+    wait_for_upload_queue_empty(pageserver_http, tenant_id, timeline_id)
+
+    uploaded_at = uploaded.stat()[8]
+    assert overwritten_at <= uploaded_at, "expected the L1 to finally be uploaded"

test_runner/regress/test_pageserver_restart.py

@@ -120,6 +120,10 @@ def test_pageserver_chaos(neon_env_builder: NeonEnvBuilder):
 
     env = neon_env_builder.init_start()
 
+    # these can happen, if we shutdown at a good time. to be fixed as part of #5172.
+    message = ".*duplicated L1 layer layer=.*"
+    env.pageserver.allowed_errors.append(message)
+
     # Use a tiny checkpoint distance, to create a lot of layers quickly.
     # That allows us to stress the compaction and layer flushing logic more.
     tenant, _ = env.neon_cli.create_tenant(

test_runner/regress/test_timeline_delete.py

@@ -34,6 +34,7 @@ from fixtures.remote_storage import (
 )
 from fixtures.types import Lsn, TenantId, TimelineId
 from fixtures.utils import query_scalar, run_pg_bench_small, wait_until
+from urllib3.util.retry import Retry
 
 
 def test_timeline_delete(neon_simple_env: NeonEnv):
@@ -614,7 +615,7 @@ def test_delete_timeline_client_hangup(neon_env_builder: NeonEnvBuilder):
 
     child_timeline_id = env.neon_cli.create_branch("child", "main")
 
-    ps_http = env.pageserver.http_client()
+    ps_http = env.pageserver.http_client(retries=Retry(0, read=False))
 
     failpoint_name = "persist_deleted_index_part"
     ps_http.configure_failpoints((failpoint_name, "pause"))
@@ -854,7 +855,7 @@ def test_timeline_delete_resumed_on_attach(
             # error from http response is also logged
             ".*InternalServerError\\(Tenant is marked as deleted on remote storage.*",
             # Polling after attach may fail with this
-            f".*InternalServerError\\(Tenant {tenant_id} is not active.*",
+            ".*Resource temporarily unavailable.*Tenant not yet active",
             '.*shutdown_pageserver{exit_code=0}: stopping left-over name="remote upload".*',
         )
     )

test_runner/regress/test_wal_acceptor.py

@@ -801,6 +801,9 @@ def test_timeline_status(neon_env_builder: NeonEnvBuilder, auth_enabled: bool):
         wa_http_cli_debug = wa.http_client(auth_token=env.auth_keys.generate_safekeeper_token())
         wa_http_cli_debug.check_status()
 
+    # create a dummy table to wait for timeline initialization in safekeeper
+    endpoint.safe_psql("create table wait_for_sk()")
+
     # fetch something sensible from status
     tli_status = wa_http_cli.timeline_status(tenant_id, timeline_id)
     epoch = tli_status.acceptor_epoch