Sort directory objects correctly (#10886)

Decode dir objects when listing and sort them correctly.

cmd/metacache-set.go

@@ -539,7 +539,7 @@ func (er *erasureObjects) streamMetadataParts(ctx context.Context, o listPathOpt
 func (er *erasureObjects) listPath(ctx context.Context, o listPathOptions) (entries metaCacheEntriesSorted, err error) {
 	const debugPrint = false
 	if debugPrint {
-		console.Printf("listPath with options: %#v", o)
+		console.Printf("listPath with options: %#v\n", o)
 	}
 	// See if we have the listing stored.
 	if !o.Create {

cmd/metacache-walk.go

@@ -96,9 +96,16 @@ func (s *xlStorage) WalkDir(ctx context.Context, opts WalkDirOptions, wr io.Writ
 			// Forward some errors?
 			return nil
 		}
-
+		dirObjects := make(map[string]struct{})
 		for i, entry := range entries {
 			if strings.HasSuffix(entry, slashSeparator) {
+				if strings.HasSuffix(entry, globalDirSuffixWithSlash) {
+					// Add without extension so it is sorted correctly.
+					entry = strings.TrimSuffix(entry, globalDirSuffixWithSlash) + slashSeparator
+					dirObjects[entry] = struct{}{}
+					entries[i] = entry
+					continue
+				}
 				// Trim slash, maybe compiler is clever?
 				entries[i] = entries[i][:len(entry)-1]
 				continue
@@ -116,6 +123,7 @@ func (s *xlStorage) WalkDir(ctx context.Context, opts WalkDirOptions, wr io.Writ
 				}
 				meta.name = strings.TrimSuffix(meta.name, xlStorageFormatFile)
 				meta.name = strings.TrimSuffix(meta.name, SlashSeparator)
+				meta.name = decodeDirObject(meta.name)
 				out <- meta
 				return nil
 			}
@@ -158,10 +166,18 @@ func (s *xlStorage) WalkDir(ctx context.Context, opts WalkDirOptions, wr io.Writ
 
 			// All objects will be returned as directories, there has been no object check yet.
 			// Check it by attempting to read metadata.
+			_, isDirObj := dirObjects[entry]
+			if isDirObj {
+				meta.name = meta.name[:len(meta.name)-1] + globalDirSuffixWithSlash
+			}
+
 			meta.metadata, err = ioutil.ReadFile(pathJoin(volumeDir, meta.name, xlStorageFormatFile))
 			switch {
 			case err == nil:
 				// It was an object
+				if isDirObj {
+					meta.name = strings.TrimSuffix(meta.name, globalDirSuffixWithSlash) + slashSeparator
+				}
 				out <- meta
 			case os.IsNotExist(err):
 				meta.metadata, err = ioutil.ReadFile(pathJoin(volumeDir, meta.name, xlStorageFormatFileV1))
@@ -174,7 +190,10 @@ func (s *xlStorage) WalkDir(ctx context.Context, opts WalkDirOptions, wr io.Writ
 				}
 
 				// NOT an object, append to stack (with slash)
+				// If dirObject, but no metadata (which is unexpected) we skip it.
+				if !isDirObj {
 					dirStack = append(dirStack, meta.name+slashSeparator)
+				}
 			default:
 				logger.LogIf(ctx, err)
 			}