# tune2fs -l /dev/sda3 | grep -i 'block'
Block count:              9865984
Reserved block count:     493299
Free blocks:              8871467
First block:              0
Block size:               4096
Reserved GDT blocks:      1024
Blocks per group:         32768
Inode blocks per group:   511
Flex block group size:    16
Reserved blocks uid:      0 (user root)
Reserved blocks gid:      0 (group root)
Journal backup:           inode blocks