From cdd7512a2e45bdce415d4d6113b1b49c867bf398 Mon Sep 17 00:00:00 2001
From: Poorna <poornas@users.noreply.github.com>
Date: Wed, 11 Sep 2024 09:08:51 -0700
Subject: [PATCH] use rename() safety for in-place 'xl.meta' updates (#20414)

---
 cmd/xl-storage.go | 46 +++++++++++++++++++++++++++++++++++++++++++---
 go.mod            |  3 ++-
 go.sum            |  4 ++--
 3 files changed, 47 insertions(+), 6 deletions(-)

diff --git a/cmd/xl-storage.go b/cmd/xl-storage.go
index 570cc7d2e..f1b51fe6b 100644
--- a/cmd/xl-storage.go
+++ b/cmd/xl-storage.go
@@ -45,6 +45,7 @@ import (
 	"github.com/minio/minio/internal/bucket/lifecycle"
 	"github.com/minio/minio/internal/cachevalue"
 	"github.com/minio/minio/internal/config/storageclass"
+
 	"github.com/minio/minio/internal/disk"
 	xioutil "github.com/minio/minio/internal/ioutil"
 	"github.com/minio/minio/internal/logger"
@@ -1404,7 +1405,7 @@ func (s *xlStorage) DeleteVersion(ctx context.Context, volume, path string, fi F
 			return err
 		}
 
-		return s.WriteAll(ctx, volume, pathJoin(path, xlStorageFormatFile), buf)
+		return s.writeAllMeta(ctx, volume, pathJoin(path, xlStorageFormatFile), buf, true)
 	}
 
 	if opts.UndoWrite && opts.OldDataDir != "" {
@@ -1459,7 +1460,7 @@ func (s *xlStorage) UpdateMetadata(ctx context.Context, volume, path string, fi
 	}
 	defer metaDataPoolPut(wbuf)
 
-	return s.writeAll(ctx, volume, pathJoin(path, xlStorageFormatFile), wbuf, !opts.NoPersistence, volumeDir)
+	return s.writeAllMeta(ctx, volume, pathJoin(path, xlStorageFormatFile), wbuf, !opts.NoPersistence)
 }
 
 // WriteMetadata - writes FileInfo metadata for path at `xl.meta`
@@ -2210,7 +2211,8 @@ func (s *xlStorage) writeAllDirect(ctx context.Context, filePath string, fileSiz
 	return w.Close()
 }
 
-func (s *xlStorage) writeAll(ctx context.Context, volume string, path string, b []byte, sync bool, skipParent string) (err error) {
+// writeAllMeta - writes all metadata to a temp file and then links it to the final destination.
+func (s *xlStorage) writeAllMeta(ctx context.Context, volume string, path string, b []byte, sync bool) (err error) {
 	if contextCanceled(ctx) {
 		return ctx.Err()
 	}
@@ -2225,6 +2227,26 @@ func (s *xlStorage) writeAll(ctx context.Context, volume string, path string, b
 		return err
 	}
 
+	tmpVolumeDir, err := s.getVolDir(minioMetaTmpBucket)
+	if err != nil {
+		return err
+	}
+
+	tmpFilePath := pathJoin(tmpVolumeDir, mustGetUUID())
+	defer func() {
+		if err != nil {
+			Remove(tmpFilePath)
+		}
+	}()
+
+	if err = s.writeAllInternal(ctx, tmpFilePath, b, sync, tmpVolumeDir); err != nil {
+		return err
+	}
+
+	return renameAll(tmpFilePath, filePath, volumeDir)
+}
+
+func (s *xlStorage) writeAllInternal(ctx context.Context, filePath string, b []byte, sync bool, skipParent string) (err error) {
 	flags := os.O_CREATE | os.O_WRONLY | os.O_TRUNC
 
 	var w *os.File
@@ -2269,6 +2291,24 @@ func (s *xlStorage) writeAll(ctx context.Context, volume string, path string, b
 	return w.Close()
 }
 
+func (s *xlStorage) writeAll(ctx context.Context, volume string, path string, b []byte, sync bool, skipParent string) (err error) {
+	if contextCanceled(ctx) {
+		return ctx.Err()
+	}
+
+	volumeDir, err := s.getVolDir(volume)
+	if err != nil {
+		return err
+	}
+
+	filePath := pathJoin(volumeDir, path)
+	if err = checkPathLength(filePath); err != nil {
+		return err
+	}
+
+	return s.writeAllInternal(ctx, filePath, b, sync, skipParent)
+}
+
 func (s *xlStorage) WriteAll(ctx context.Context, volume string, path string, b []byte) (err error) {
 	// Specific optimization to avoid re-read from the drives for `format.json`
 	// in-case the caller is a network operation.
diff --git a/go.mod b/go.mod
index 2d3f3bb53..9342ae9dc 100644
--- a/go.mod
+++ b/go.mod
@@ -94,7 +94,7 @@ require (
 	golang.org/x/exp v0.0.0-20240823005443-9b4947da3948
 	golang.org/x/oauth2 v0.22.0
 	golang.org/x/sync v0.8.0
-	golang.org/x/sys v0.24.0
+	golang.org/x/sys v0.25.0
 	golang.org/x/term v0.23.0
 	golang.org/x/time v0.6.0
 	google.golang.org/api v0.194.0
@@ -254,4 +254,5 @@ require (
 	google.golang.org/genproto/googleapis/rpc v0.0.0-20240823204242-4ba0660f739c // indirect
 	google.golang.org/grpc v1.65.0 // indirect
 	google.golang.org/protobuf v1.34.2 // indirect
+
 )
diff --git a/go.sum b/go.sum
index 77dbad028..ecc0ef87b 100644
--- a/go.sum
+++ b/go.sum
@@ -781,8 +781,8 @@ golang.org/x/sys v0.8.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.17.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 golang.org/x/sys v0.18.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 golang.org/x/sys v0.21.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
-golang.org/x/sys v0.24.0 h1:Twjiwq9dn6R1fQcyiK+wQyHWfaz/BJB+YIpzU/Cv3Xg=
-golang.org/x/sys v0.24.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+golang.org/x/sys v0.25.0 h1:r+8e+loiHxRqhXVl6ML1nO3l1+oFoWbnlu2Ehimmi34=
+golang.org/x/sys v0.25.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 golang.org/x/term v0.0.0-20201117132131-f5c789dd3221/go.mod h1:Nr5EML6q2oocZ2LXRh80K7BxOlk5/8JxuGnuhpl+muw=
 golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
 golang.org/x/term v0.0.0-20210927222741-03fcf44c2211/go.mod h1:jbD1KX2456YbFQfuXm/mYQcufACuNUgVhRMnK/tPxf8=