From f00fb4706c4c2459d528fb5f8ad0fa112b00bdd0 Mon Sep 17 00:00:00 2001
From: Simon Ruderich <simon@ruderich.org>
Date: Sat, 16 Jan 2021 11:34:59 +0100
Subject: [PATCH] Guarantee durability after renaming temporary files
---
file.go | 6 +++++-
main.go | 6 +++++-
misc.go | 22 ++++++++++++++++++++++
state.go | 6 +++++-
4 files changed, 37 insertions(+), 3 deletions(-)
diff --git a/file.go b/file.go
index 1d102a4..3884bba 100644
--- a/file.go
+++ b/file.go
@@ -198,5 +198,9 @@ func deployFile(file *File) error {
if err != nil {
return err
}
- return f.CloseAtomicallyReplace()
+ err = f.CloseAtomicallyReplace()
+ if err != nil {
+ return err
+ }
+ return syncPath(filepath.Dir(file.Path))
}
diff --git a/main.go b/main.go
index 9b12752..7a7d8b0 100644
--- a/main.go
+++ b/main.go
@@ -151,5 +151,9 @@ func mainConvert(typ, srcPath, dstPath string) error {
return err
}
- return f.CloseAtomicallyReplace()
+ err = f.CloseAtomicallyReplace()
+ if err != nil {
+ return err
+ }
+ return syncPath(filepath.Dir(dstPath))
}
diff --git a/misc.go b/misc.go
index 897a764..3cbe90f 100644
--- a/misc.go
+++ b/misc.go
@@ -20,6 +20,7 @@ package main
import (
"bytes"
"fmt"
+ "os"
)
func alignBufferTo(b *bytes.Buffer, align int) {
@@ -35,3 +36,24 @@ func alignBufferTo(b *bytes.Buffer, align int) {
b.WriteByte(0)
}
}
+
+// syncPath syncs path, which should be a directory. To guarantee durability
+// it must be called on a parent directory after adding, renaming or removing
+// files therein.
+//
+// Calling sync on the files itself is not enough according to POSIX; man 2
+// fsync: "Calling fsync() does not necessarily ensure that the entry in the
+// directory containing the file has also reached disk. For that an explicit
+// fsync() on a file descriptor for the directory is also needed."
+func syncPath(path string) error {
+ x, err := os.Open(path)
+ if err != nil {
+ return err
+ }
+ err = x.Sync()
+ closeErr := x.Close()
+ if err != nil {
+ return err
+ }
+ return closeErr
+}
diff --git a/state.go b/state.go
index be08e72..59c885a 100644
--- a/state.go
+++ b/state.go
@@ -80,5 +80,9 @@ func WriteState(path string, state *State) error {
if err != nil {
return err
}
- return f.CloseAtomicallyReplace()
+ err = f.CloseAtomicallyReplace()
+ if err != nil {
+ return err
+ }
+ return syncPath(filepath.Dir(path))
}
--
2.49.0