ext3:

After initial population:

  File: "/mnt/test"
    ID: 566f3782b6b5b1a6 Namelen: 255     Type: ext2/ext3
Block size: 4096       Fundamental block size: 4096
Blocks: Total: 20961959   Free: 4067979    Available: 3003172
Inodes: Total: 5324800    Free: 3827285

After [ABCDEF] file removal:

  File: "/mnt/test"
    ID: 566f3782b6b5b1a6 Namelen: 255     Type: ext2/ext3
Block size: 4096       Fundamental block size: 4096
Blocks: Total: 20961959   Free: 4287379    Available: 3222572
Inodes: Total: 5324800    Free: 3862237