21. The superblock data layout

• Super block layout contains the following fields:

  • block size

  • file system size (the total number of blocks)

    • NOTE: there could be hidden data following the file system, which is called volume slack.

  • the number of blocks per block group

  • the number of reserved blocks before the first block group

  • number of free blocks

  • list of free blocks

  • the size of inode list (total number of inodes)

  • the number of inodes per block group

  • list of free inodes