From 71e63296a202a7da5eea2d0227517f66069cfa63 Mon Sep 17 00:00:00 2001
From: Alex Crichton <alex@alexcrichton.com>
Date: Sun, 1 May 2016 22:33:22 -0700
Subject: [PATCH] rustc: Handle concurrent `create_dir` requests
The compiler created a directory as part of `-Z incremental` but that may be
hierarchically used concurrently so we need to protect ourselves against that.
---
src/librustc_incremental/persist/util.rs | 26 ++++++++++++++++++++++--
1 file changed, 24 insertions(+), 2 deletions(-)
diff --git a/src/librustc_incremental/persist/util.rs b/src/librustc_incremental/persist/util.rs
index 9b4e5997efe4..5b4e88def018 100644
--- a/src/librustc_incremental/persist/util.rs
+++ b/src/librustc_incremental/persist/util.rs
@@ -9,14 +9,16 @@
// except according to those terms.
use rustc::ty;
+
use std::fs;
-use std::path::PathBuf;
+use std::io;
+use std::path::{PathBuf, Path};
pub fn dep_graph_path<'tcx>(tcx: &ty::TyCtxt<'tcx>) -> Option<PathBuf> {
// For now, just save/load dep-graph from
// directory/dep_graph.rbml
tcx.sess.opts.incremental.as_ref().and_then(|incr_dir| {
- match fs::create_dir_all(&incr_dir){
+ match create_dir_racy(&incr_dir) {
Ok(()) => {}
Err(err) => {
tcx.sess.err(
@@ -30,3 +32,23 @@ pub fn dep_graph_path<'tcx>(tcx: &ty::TyCtxt<'tcx>) -> Option<PathBuf> {
})
}
+// Like std::fs::create_dir_all, except handles concurrent calls among multiple
+// threads or processes.
+fn create_dir_racy(path: &Path) -> io::Result<()> {
+ match fs::create_dir(path) {
+ Ok(()) => return Ok(()),
+ Err(ref e) if e.kind() == io::ErrorKind::AlreadyExists => return Ok(()),
+ Err(ref e) if e.kind() == io::ErrorKind::NotFound => {}
+ Err(e) => return Err(e),
+ }
+ match path.parent() {
+ Some(p) => try!(create_dir_racy(p)),
+ None => return Err(io::Error::new(io::ErrorKind::Other,
+ "failed to create whole tree")),
+ }
+ match fs::create_dir(path) {
+ Ok(()) => Ok(()),
+ Err(ref e) if e.kind() == io::ErrorKind::AlreadyExists => Ok(()),
+ Err(e) => Err(e),
+ }
+}