docker-stable/0008-bsc1214855-volume-use-AtomicWriteFile-to-save-volume.patch

From 12c8b7a22f7140b5b4d2c87a7e5d70da082fe558 Mon Sep 17 00:00:00 2001
From: Aleksa Sarai <cyphar@cyphar.com>
Date: Wed, 19 Jun 2024 16:30:49 +1000
Subject: [PATCH 08/11] bsc1214855: volume: use AtomicWriteFile to save volume
 options

If the system (or Docker) crashes while saivng the volume options, on
restart the daemon will error out when trying to read the options file
because it doesn't contain valid JSON.

In such a crash scenario, the new volume will be treated as though it
has the default options configuration. This is not ideal, but volumes
created on very old Docker versions (pre-1.11[1], circa 2016) do not
have opts.json and so doing some kind of cleanup when loading the volume
store (even if we take care to only delete empty volumes) could delete
existing volumes carried over from very old Docker versions that users
would not expect to disappear.

Ultimately, if a user creates a volume and the system crashes, a volume
that has the wrong config is better than Docker not being able to start.

[1]: commit b05b2370757d ("Support mount opts for `local` volume driver")

SUSE-Bugs: https://bugzilla.suse.com/show_bug.cgi?id=1214855
(Cherry-picked from commit b4c20da143502e5fc21cc4996b63e83691c515bf.)
Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>
---
 volume/local/local.go | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/volume/local/local.go b/volume/local/local.go
index b4f3a3669a84..077b26f1b813 100644
--- a/volume/local/local.go
+++ b/volume/local/local.go
@@ -16,6 +16,7 @@ import (
 	"github.com/docker/docker/daemon/names"
 	"github.com/docker/docker/errdefs"
 	"github.com/docker/docker/pkg/idtools"
+	"github.com/docker/docker/pkg/ioutils"
 	"github.com/docker/docker/quota"
 	"github.com/docker/docker/volume"
 	"github.com/pkg/errors"
@@ -381,7 +382,7 @@ func (v *localVolume) saveOpts() error {
 	if err != nil {
 		return err
 	}
-	err = os.WriteFile(filepath.Join(v.rootPath, "opts.json"), b, 0600)
+	err = ioutils.AtomicWriteFile(filepath.Join(v.rootPath, "opts.json"), b, 0o600)
 	if err != nil {
 		return errdefs.System(errors.Wrap(err, "error while persisting volume options"))
 	}
-- 
2.47.1