我正在 VirtualBox VM、Lubuntu 上测试hf命令，分配了 30 Gb 的虚拟驱动器（注意：真正的 Gb 不是 gibi/mebi 的东西）。但是当我使用hf命令时会发生一些非常奇怪的事情：
root@vbox:~# df -h
Filesystem Size Used Avail Use% Mounted on
tmpfs 292M 1,2M 291M 1% /run
/dev/sda1 30G 20G 8,2G 71% /
tmpfs 1,5G 0 1,5G 0% /dev/shm
tmpfs 5,0M 4,0K 5,0M 1% /run/lock
tmpfs 4,0M 0 4,0M 0% /sys/fs/cgroup
tmpfs 292M 92K 292M 1% /run/user/1000
root@vbox:~# df
Filesystem 1K-blocks Used Available Use% Mounted on
tmpfs 298632 1180 297452 1% /run
/dev/sda1 30833564 20826180 8523272 71% /
tmpfs 1493144 0 1493144 0% /dev/shm
tmpfs 5120 4 5116 1% /run/lock
tmpfs 4096 0 4096 0% /sys/fs/cgroup
tmpfs 298628 92 298536 1% /run/user/1000
root@vbox:~# df --block-size=1
Filesystem 1B-blocks Used Available Use% Mounted on
tmpfs 305799168 1208320 304590848 1% /run
/dev/sda1 31573569536 21326008320 8727830528 71% /
tmpfs 1528979456 0 1528979456 0% /dev/shm
tmpfs 5242880 4096 5238784 1% /run/lock
tmpfs 4194304 0 4194304 0% /sys/fs/cgroup
tmpfs 305795072 94208 305700864 1% /run/user/1000
root@vbox:~# tune2fs -l /dev/sda1
tune2fs 1.46.5 (30-Dec-2021)
Filesystem volume name: <none>
Last mounted on: /
Filesystem UUID: eb1f771e-14d9-461b-98b4-1e399a7ddeb0
Filesystem magic number: 0xEF53
Filesystem revision #: 1 (dynamic)
Filesystem features: has_journal ext_attr resize_inode dir_index filetype needs_recovery extent 64bit flex_bg sparse_super large_file huge_file dir_nlink extra_isize metadata_csum
Filesystem flags: signed_directory_hash
Default mount options: user_xattr acl
Filesystem state: clean
Errors behavior: Continue
Filesystem OS type: Linux
Inode count: 1974272
Block count: 7865088
Reserved block count: 366932
Free blocks: 3060668
Free inodes: 1637218
First block: 0
Block size: 4096
Fragment size: 4096
Group descriptor size: 64
Reserved GDT blocks: 1023
Blocks per group: 32768
Fragments per group: 32768
Inodes per group: 8192
Inode blocks per group: 512
Flex block group size: 16
Filesystem created: Mon Dec 7 20:34:27 2020
Last mount time: Sat Jul 29 08:28:43 2023
Last write time: Sat Jul 29 08:28:43 2023
Mount count: 31
Maximum mount count: -1
Last checked: Mon Dec 7 20:34:27 2020
Check interval: 0 (<none>)
Lifetime writes: 36 GB
Reserved blocks uid: 0 (user root)
Reserved blocks gid: 0 (group root)
First inode: 11
Inode size: 256
Required extra isize: 32
Desired extra isize: 32
Journal inode: 8
First orphan inode: 1186725
Default directory hash: half_md4
Directory Hash Seed: fd016d91-9723-4dcc-9880-0b2a65e0bb49
Journal backup: inode blocks
Checksum type: crc32c
Checksum: 0x54deee1a
正如您所看到的，df -h返回了正确的精确 30 Gb，而裸露df或df --block-size=1返回了大约600 000 000字节。
更有趣的是，tune2fs -l /dev/sda1显示了 4k 块的正确数量，总计为32 215 400 448字节或30.0029 Gb。
这当然不是 5% 保留块的问题，因为df Size列必须返回绝对字节总数。这该如何解释呢？