fix(dir2block): support multi block entry

xfs/inode.go

@@ -741,63 +741,55 @@ func (xfs *FileSystem) parseDir2Block(bmbtIrec BmbtIrec) ([]Dir2DataEntry, error
 
 	var buf []byte
 	for blockOffset := bmbtIrec.StartBlock; blockOffset < bmbtIrec.StartBlock+bmbtIrec.BlockCount; blockOffset++ {
-		blockData, err := xfs.readBlockFromLogicalBlockOffset(blockOffset)
+		physicalBlockOffset := xfs.PrimaryAG.SuperBlock.BlockToPhysicalOffset(blockOffset)
+		_, err := xfs.seekBlock(physicalBlockOffset)
 		if err != nil {
-			return nil, xerrors.Errorf("failed to read block from logical block offset: %w", err)
+			return nil, xerrors.Errorf("failed to seek block: %w", err)
+		}
+		blockData, err := utils.ReadBlock(xfs.r)
+		if err != nil {
+			return nil, xerrors.Errorf("failed to read block: %w", err)
 		}
 		buf = append(buf, blockData...)
 
-		// if the next block is not a leader, it is a continuation of the current block.
-		if blockOffset == bmbtIrec.StartBlock+bmbtIrec.BlockCount-1 &&
-			!xfs.nextBlockIsLeader(blockOffset) {
+		// if the next block is not a leader, it is a continuation of the previous block
+		if blockOffset != bmbtIrec.StartBlock+bmbtIrec.BlockCount-1 && // not last block
+			!xfs.nextBlockIsLeader(blockOffset) { // not leader
 			continue
 		}
 
-		magicBytes := binary.BigEndian.Uint32(blockData[:4])
-		reader := bytes.NewReader(blockData)
+		// if the next block is a leader, it is the last block of the directory
+		magicBytes := binary.BigEndian.Uint32(buf[:4])
+		reader := bytes.NewReader(buf)
+		if err := binary.Read(reader, binary.BigEndian, &block.Header); err != nil {
+			return nil, xerrors.Errorf("failed to parse dir3 data header error: %w", err)
+		}
 		switch magicBytes {
 		case XFS_DIR3_DATA_MAGIC:
-			if err := binary.Read(reader, binary.BigEndian, &block.Header); err != nil {
-				return nil, xerrors.Errorf("failed to parse dir3 data header error: %w", err)
-			}
 			entries, err := xfs.parseXDD3Block(reader)
 			if err != nil {
 				return nil, xerrors.Errorf("failed to parse XDD3 block: %w", err)
 			}
 			block.Entries = append(block.Entries, entries...)
-			buf = []byte{}
-
 		case XFS_DIR3_BLOCK_MAGIC:
-			if err := binary.Read(reader, binary.BigEndian, &block.Header); err != nil {
-				return nil, xerrors.Errorf("failed to parse dir3 block header error: %w", err)
-			}
 			entries, err := xfs.parseXDB3Block(reader)
 			if err != nil {
 				return nil, xerrors.Errorf("failed to parse XDB3 block: %w", err)
 			}
 			block.Entries = append(block.Entries, entries...)
-			buf = []byte{}
+		default:
+			return nil, xerrors.Errorf("unknown magic bytes: %x", magicBytes)
 		}
+
+		// reset buf
+		buf = []byte{}
 	}
 
 	return block.Entries, nil
 }
 
-func (xfs *FileSystem) readBlockFromLogicalBlockOffset(n uint64) ([]byte, error) {
-	physicalBlockOffset := xfs.PrimaryAG.SuperBlock.BlockToPhysicalOffset(n)
-	_, err := xfs.seekBlock(physicalBlockOffset)
-	if err != nil {
-		return nil, xerrors.Errorf("failed to seek block: %w", err)
-	}
-	blockData, err := utils.ReadBlock(xfs.r)
-	if err != nil {
-		return nil, xerrors.Errorf("failed to read block: %w", err)
-	}
-	return blockData, nil
-}
-
 func (xfs *FileSystem) nextBlockIsLeader(blockOffset uint64) bool {
-	physicalBlockOffset := xfs.PrimaryAG.SuperBlock.BlockToPhysicalOffset(blockOffset - 1)
+	physicalBlockOffset := xfs.PrimaryAG.SuperBlock.BlockToPhysicalOffset(blockOffset + 1)
 	xfs.seekBlock(physicalBlockOffset)
 	blockData, _ := utils.ReadBlock(xfs.r)