test: verify commit metadata loss and write quorum boundaries

Signed-off-by: Feng Ruohang <rh@vonng.com>

cmd/xl-storage-errors_test.go

@@ -18,11 +18,16 @@
 package cmd
 
 import (
+	"context"
 	"errors"
+	"net/http"
 	"os"
+	"path/filepath"
 	"runtime"
+	"sync"
 	"syscall"
 	"testing"
+	"time"
 )
 
 func TestSysErrors(t *testing.T) {
@@ -81,4 +86,96 @@ func TestCommitMetaMissingMapping(t *testing.T) {
 	if qerr.Bucket != "bucket" || qerr.Object != "object" {
 		t.Fatalf("unexpected bucket/object %s/%s", qerr.Bucket, qerr.Object)
 	}
+	apiErr := toAPIError(t.Context(), err)
+	if apiErr.Code != "SlowDownWrite" || apiErr.HTTPStatusCode != http.StatusServiceUnavailable {
+		t.Fatalf("expected SlowDownWrite/503, got %+v", apiErr)
+	}
+}
+
+// missingCommitMetaContext removes staged metadata at an existing cancellation
+// check, after WriteAll and (for non-inline objects) the data rename succeeded.
+// This deterministically models concurrent cleanup without changing production
+// code or relying on a filesystem race. The context itself remains live.
+type missingCommitMetaContext struct {
+	context.Context
+	mu             sync.Mutex
+	meta, dataDest string
+	removed        bool
+	removeErr      error
+}
+
+func (c *missingCommitMetaContext) Done() <-chan struct{} {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	if !c.removed {
+		if _, err := os.Stat(c.meta); err == nil {
+			dataMoved := c.dataDest == ""
+			if !dataMoved {
+				_, err = os.Stat(c.dataDest)
+				dataMoved = err == nil
+			}
+			if dataMoved {
+				c.removeErr = os.Remove(c.meta)
+				c.removed = c.removeErr == nil
+			}
+		}
+	}
+	return c.Context.Done()
+}
+
+func TestXLStorageRenameDataCommitMetaMissing(t *testing.T) {
+	for _, tc := range []struct {
+		name     string
+		dataFile bool
+	}{
+		{"empty_object", false},
+		{"data_directory", true},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			disk, root, err := newXLStorageTestSetup(t)
+			if err != nil {
+				t.Fatal(err)
+			}
+			defer disk.Close()
+			s := disk.storage
+			if err := s.MakeVol(t.Context(), "bucket"); err != nil {
+				t.Fatal(err)
+			}
+			fi := newFileInfo("object", 2, 2)
+			fi.DataDir, fi.VersionID = mustGetUUID(), mustGetUUID()
+			fi.Erasure.Index = 1
+			fi.ModTime = time.Now().UTC()
+			fi.Fresh = true
+			ctx := &missingCommitMetaContext{
+				Context: t.Context(),
+				meta:    filepath.Join(root, minioMetaTmpBucket, "staged", xlStorageFormatFile),
+			}
+			if tc.dataFile {
+				fi.Size = 1
+				fi.AddObjectPart(1, "", 1, 1, fi.ModTime, nil, nil)
+				part := filepath.Join(root, minioMetaTmpBucket, "staged", fi.DataDir, "part.1")
+				if err := os.MkdirAll(filepath.Dir(part), 0o755); err != nil {
+					t.Fatal(err)
+				}
+				if err := os.WriteFile(part, []byte("a"), 0o644); err != nil {
+					t.Fatal(err)
+				}
+				ctx.dataDest = filepath.Join(root, "bucket", "object", fi.DataDir)
+			}
+			_, err = s.RenameData(ctx, minioMetaTmpBucket, "staged", fi, "bucket", "object", RenameOptions{})
+			if !ctx.removed {
+				t.Fatalf("metadata removal did not execute: removal error = %v, RenameData error = %v", ctx.removeErr, err)
+			}
+			if !errors.Is(err, errCommitMetaMissing) {
+				t.Fatalf("expected commit metadata missing, got %v", err)
+			}
+			apiErr := toAPIError(t.Context(), toObjectErr(err, "bucket", "object"))
+			if apiErr.Code != "SlowDownWrite" || apiErr.HTTPStatusCode != http.StatusServiceUnavailable {
+				t.Fatalf("expected SlowDownWrite/503, got %+v", apiErr)
+			}
+			if _, err := os.Stat(filepath.Join(root, "bucket", "object", xlStorageFormatFile)); !os.IsNotExist(err) {
+				t.Fatalf("failed commit must not produce destination metadata: %v", err)
+			}
+		})
+	}
 }