有人能解释一下为什么我只有 170GB 空间吗？我以为我有 1GB 交换空间，其余空间在根分区上。或者有人能告诉我在哪里可以阅读更多关于这个主题的信息吗？是因为所有的 snap 吗？
df 的输出：
Filesystem 1K-blocks Used Available Use% Mounted on
udev 8136852 0 8136852 0% /dev
tmpfs 1633432 2048 1631384 1% /run
/dev/mapper/ubuntu--vg-root 238325496 177376756 48772768 79% /
tmpfs 8167156 628488 7538668 8% /dev/shm
tmpfs 5120 4 5116 1% /run/lock
tmpfs 8167156 0 8167156 0% /sys/fs/cgroup
/dev/loop2 98944 98944 0 100% /snap/core/9804
/dev/loop4 56704 56704 0 100% /snap/core18/1885
/dev/loop1 158848 158848 0 100% /snap/code/42
/dev/loop3 56320 56320 0 100% /snap/core18/1880
/dev/loop5 63616 63616 0 100% /snap/gtk-common-themes/1506
/dev/loop6 99328 99328 0 100% /snap/core/9665
/dev/loop8 170752 170752 0 100% /snap/postman/123
/dev/loop7 44288 44288 0 100% /snap/snap-store/415
/dev/loop9 58752 58752 0 100% /snap/discord/112
/dev/loop0 148480 148480 0 100% /snap/code/41
/dev/loop10 56192 56192 0 100% /snap/gtk-common-themes/1502
/dev/loop12 40576 40576 0 100% /snap/remmina/4324
/dev/loop11 39936 39936 0 100% /snap/remmina/4309
/dev/loop13 144128 144128 0 100% /snap/gnome-3-26-1604/100
/dev/loop14 58752 58752 0 100% /snap/discord/109
/dev/loop15 147712 147712 0 100% /snap/slack/25
/dev/loop16 165376 165376 0 100% /snap/gnome-3-28-1804/128
/dev/loop17 170752 170752 0 100% /snap/postman/122
/dev/loop18 2304 2304 0 100% /snap/gnome-system-monitor/148
/dev/loop19 297984 297984 0 100% /snap/vlc/1620
/dev/loop21 51072 51072 0 100% /snap/snap-store/467
/dev/loop20 297472 297472 0 100% /snap/vlc/1700
/dev/loop22 261760 261760 0 100% /snap/gnome-3-34-1804/36
/dev/loop24 144128 144128 0 100% /snap/gnome-3-26-1604/98
/dev/loop23 2304 2304 0 100% /snap/gnome-system-monitor/145
/dev/loop25 164096 164096 0 100% /snap/gnome-3-28-1804/116
/dev/loop26 261760 261760 0 100% /snap/gnome-3-34-1804/33
/dev/loop27 121856 121856 0 100% /snap/slack/27
tmpfs 1633428 48 1633380 1% /run/user/1000
/dev/sdb2 226665468 205766000 20899468 91% /media/simon/5E9C7F549C7F25A5