Debian 里更新 zfs 版本时, 总有以下报错:

Setting up zfsutils-linux (0.7.13-1) ...
zfs-import-scan.service is a disabled or a static unit, not starting it.
Job for zfs-mount.service failed because the control process exited with error code.
See "systemctl status zfs-mount.service" and "journalctl -xe" for details.
invoke-rc.d: initscript zfs-mount, action "restart" failed.
     Docs: man:zfs(8)
  Process: 51146 ExecStart=/sbin/zfs mount -a (code=exited, status=1/FAILURE)
 Main PID: 51146 (code=exited, status=1/FAILURE)
Mar 12 01:46:05 mydebian-gen8 zfs[51146]: cannot mount '/pool': directory is not empty
2 not fully installed or removed.
After this operation, 0 B of additional disk space will be used.
Do you want to continue? [Y/n] y
Setting up zfsutils-linux (0.7.13-1) ...
● zfs-mount.service - Mount ZFS filesystems
   Loaded: loaded (/lib/systemd/system/zfs-mount.service; enabled; vendor preset: enabled)
Mar 12 01:46:24 mydebian-gen8 systemd[1]: zfs-mount.service: Main process exited, code=exited, status=1/FAILURE
Mar 12 01:46:24 mydebian-gen8 systemd[1]: zfs-mount.service: Failed with result 'exit-code'.
Mar 12 01:46:24 mydebian-gen8 systemd[1]: Failed to start Mount ZFS filesystems.
dpkg: error processing package zfsutils-linux (--configure):
 zfs-zed depends on zfsutils-linux (>= 0.7.13-1); however:

即使手动将 /pool 里面挂载的zfs分区都卸载了, 仍然无法解决. 后来, 先用 umount 手动卸载里面挂的系统, 再把这个挂载目录清空即可.