我有以下内容/etc/fstab：
LABEL=cloudimg-rootfs / ext4 discard,errors=remount-ro 0 1
UUID=8ff508b8-3975-4ef9-acc1-8ea7aeec56dc /home ext4 defaults 0 2
UUID=c95405a4-4f6e-4d7c-9c23-fad75ce0ec04 /home/mail ext4 defaults 0 2
/swapfile swap 交换默认值 0 0
每当我重新启动服务器时，它都会报告卸载失败/home（但重新启动正常）。我看到 syslog 说：
Mar 03 08:55:31 systemd[1]: home-mail.mount: Deactivated successfully.
Mar 03 08:55:31 systemd[1]: Unmounted /home/mail.
Mar 03 08:55:31 systemd[1]: Unmounting /home...
Mar 03 08:55:31 systemd[1]: systemd-fsck@dev-disk-by\x2duuid-c95405a4\x2d4f6e\x2d4d7c\x2d9c23\x2dfad75ce0ec04.service: Deactivated successfully.
Mar 03 08:55:31 umount[3462067]: umount: /home: target is busy.
Mar 03 08:55:31 systemd[1]: Stopped File System Check on /dev/disk/by-uuid/c95405a4-4f6e-4d7c-9c23-fad75ce0ec04.
Mar 03 08:55:31 systemd[1]: home.mount: Mount process exited, code=exited, status=32/n/a
Mar 03 08:55:31 systemd[1]: Failed unmounting /home.
Mar 03 08:55:31 systemd[1]: systemd-fsck@dev-disk-by\x2duuid-8ff508b8\x2d3975\x2d4ef9\x2dacc1\x2d8ea7aeec56dc.service: Deactivated successfully.
Mar 03 08:55:31 systemd[1]: Stopped File System Check on /dev/disk/by-uuid/8ff508b8-3975-4ef9-acc1-8ea7aeec56dc.
我不确定如何解释那里发生了什么（似乎是在并行执行？）阅读 man fstab 似乎没有提供任何线索。这是否与嵌套挂载和/或系统试图卸载分区时访问分区的某些东西有关（例如 dovecot）？如果是这样，我如何确保在关闭之前所有东西都已完成使用它？请注意，我没有看到有关忙碌的/home/mail错误。/home/mail
lsblk
xvda 202:0 0 55G 0 disk
└─xvda1 202:1 0 55G 0 part /
xvdb 202:16 0 20T 0 disk
├─xvdb1 202:17 0 5T 0 part /home
└─xvdb2 202:18 0 15T 0 part /home/mail
xvdd 202:48 0 5G 1 disk
└─xvdd1 202:49 0 5G 1 part