[Breaking] Remove ResumableFileSlot and rely on high ulimits

ResumableFileSlot became to difficult to manage, instead of
managing resources this way, we use much higher
DEFAULT_OPEN_FILE_PERMITS, set ulimit (when unix) and warn
user if the limits are likely too low.

Breaking: Removed idle_file_descriptor_timeout_millis from config.

closes: #1288, #513, #1298, #527

flake.nix

@@ -288,6 +288,7 @@
                 "--locked"
                 "--features nix"
                 "--branch"
+                "--profile smol"
                 "--ignore-filename-regex '.*(genproto|vendor-cargo-deps|crates).*'"
               ];
               cargoLlvmCovExtraArgs = "--html --output-dir $out";

nativelink-config/src/cas_server.rs

@@ -716,21 +716,6 @@ pub struct GlobalConfig {
     #[serde(deserialize_with = "convert_numeric_with_shellexpand")]
     pub max_open_files: usize,
 
-    /// If a file descriptor is idle for this many milliseconds, it will be closed.
-    /// In the event a client or store takes a long time to send or receive data
-    /// the file descriptor will be closed, and since `max_open_files` blocks new
-    /// `open_file` requests until a slot opens up, it will allow new requests to be
-    /// processed. If a read or write is attempted on a closed file descriptor, the
-    /// file will be reopened and the operation will continue.
-    ///
-    /// On services where worker(s) and scheduler(s) live in the same process, this
-    /// also prevents deadlocks if a file->file copy is happening, but cannot open
-    /// a new file descriptor because the limit has been reached.
-    ///
-    /// Default: 1000 (1 second)
-    #[serde(default, deserialize_with = "convert_duration_with_shellexpand")]
-    pub idle_file_descriptor_timeout_millis: u64,
-
     /// This flag can be used to prevent metrics from being collected at runtime.
     /// Metrics are still able to be collected, but this flag prevents metrics that
     /// are collected at runtime (performance metrics) from being tallied. The

nativelink-macro/src/lib.rs

@@ -36,12 +36,10 @@ pub fn nativelink_test(attr: TokenStream, item: TokenStream) -> TokenStream {
         async fn #fn_name(#fn_inputs) #fn_output {
             // Error means already initialized, which is ok.
             let _ = nativelink_util::init_tracing();
-            // If already set it's ok.
-            let _ = nativelink_util::fs::set_idle_file_descriptor_timeout(std::time::Duration::from_millis(100));
 
             #[warn(clippy::disallowed_methods)]
             ::std::sync::Arc::new(::nativelink_util::origin_context::OriginContext::new()).wrap_async(
-                ::nativelink_util::__tracing::trace_span!("test"), async move {
+                ::nativelink_util::__tracing::error_span!(stringify!(#fn_name)), async move {
                     #fn_block
                 }
             )

nativelink-store/Cargo.toml

@@ -78,9 +78,6 @@ aws-sdk-s3 = { version = "=1.68.0", features = [
   "rt-tokio",
 ], default-features = false }
 aws-smithy-runtime-api = "1.7.3"
-serial_test = { version = "3.2.0", features = [
-  "async",
-], default-features = false }
 serde_json = "1.0.135"
 fred = { version = "10.0.3", default-features = false, features = ["mocks"] }
 tracing-subscriber = { version = "0.3.19", default-features = false }

nativelink-store/src/fast_slow_store.rs

@@ -14,6 +14,7 @@
 
 use std::borrow::BorrowMut;
 use std::cmp::{max, min};
+use std::ffi::OsString;
 use std::ops::Range;
 use std::pin::Pin;
 use std::sync::atomic::{AtomicU64, Ordering};
@@ -224,9 +225,10 @@ impl StoreDriver for FastSlowStore {
     async fn update_with_whole_file(
         self: Pin<&Self>,
         key: StoreKey<'_>,
-        mut file: fs::ResumeableFileSlot,
+        path: OsString,
+        mut file: fs::FileSlot,
         upload_size: UploadSizeInfo,
-    ) -> Result<Option<fs::ResumeableFileSlot>, Error> {
+    ) -> Result<Option<fs::FileSlot>, Error> {
         if self
             .fast_store
             .optimized_for(StoreOptimizations::FileUpdates)
@@ -246,7 +248,7 @@ impl StoreDriver for FastSlowStore {
             }
             return self
                 .fast_store
-                .update_with_whole_file(key, file, upload_size)
+                .update_with_whole_file(key, path, file, upload_size)
                 .await;
         }
 
@@ -269,7 +271,7 @@ impl StoreDriver for FastSlowStore {
             }
             return self
                 .slow_store
-                .update_with_whole_file(key, file, upload_size)
+                .update_with_whole_file(key, path, file, upload_size)
                 .await;
         }