当服务器安装或未安装时，如何对服务器不能同意的zfs数据集进行故障排除？

Question

我有一个/proc/mounts和/etc/mtab中存在的ZFS数据集，但是文件系统中不存在文件夹，zfs umount报告数据集不存在，zfs mount报告数据集已经挂载。

这是在运行zfs dkms 2.1.11-1的RHEL 8.8 (完全更新)上完成的。

是否可以在不重新启动服务器的情况下收集此数据集？我如何开始解决这类问题呢？

我认为，当它在dataset上启用了sharenfs设置，然后在nfs守护进程共享时尝试使用zfs umount时，就会发生这种情况。我尝试过设置sharenfs=off (它成功了，但没有解决问题)。nfs服务已经关闭，问题仍在发生。我可以将数据集zfs send到另一个系统，并验证它们是否完好无损，但我只需要将它们安装在此服务器上。

我不使用容器或附加的挂载名称空间(据我所知)。

挂载列在/etc/mtab和/proc/mounts中。

topher@nzxt:/$ grep Backups -H /etc/mtab /proc/mounts
/etc/mtab:array/Backups /array/Backups zfs rw,seclabel,nosuid,nodev,noexec,noatime,xattr,noacl 0 0
/etc/mtab:array/Backups/gwen /array/Backups/gwen zfs rw,seclabel,nosuid,nodev,noexec,noatime,xattr,noacl 0 0
/proc/mounts:array/Backups /array/Backups zfs rw,seclabel,nosuid,nodev,noexec,noatime,xattr,noacl 0 0
/proc/mounts:array/Backups/gwen /array/Backups/gwen zfs rw,seclabel,nosuid,nodev,noexec,noatime,xattr,noacl 0 0

该目录不存在于文件系统中

topher@nzxt:/$ ls /array/Backups
ls: cannot access '/array/Backups': No such file or directory

数据集确实存在于zfs中(池是array)。

topher@nzxt:/$ zfs list array/Backups array/Backups/gwen
NAME                 USED  AVAIL     REFER  MOUNTPOINT
array/Backups       2.62T  1.59T     1.71T  /array/Backups
array/Backups/gwen   364G  1.59T      364G  /array/Backups/gwen

安装失败(懒惰、强迫或其他原因)。

topher@nzxt:/$ sudo zfs umount array/Backups
cannot unmount '/array/Backups/gwen': no such pool or dataset

topher@nzxt:/$ sudo zfs umount array/Backups/gwen
cannot unmount '/array/Backups/gwen': no such pool or dataset

topher@nzxt:/$ sudo umount /array/Backups/gwen
umount: /array/Backups/gwen: no mount point specified.

topher@nzxt:/$ sudo umount /array/Backups
umount: /array/Backups: no mount point specified.

我也无法导出zfs池。

topher@nzxt:~$ sudo zpool export array
cannot unmount '/array/Backups/gwen': unmount failed

尝试重新装入已挂载的目录报告

topher@nzxt:/$ sudo zfs mount array/Backups
cannot mount 'array/Backups': filesystem already mounted

topher@nzxt:/$ sudo zfs mount array/Backups/gwen
cannot mount 'array/Backups/gwen': filesystem already mounted

lsof引发试图遍历受影响目录的错误，并且在这些路径中不返回任何打开的文件句柄。

topher@nzxt:/$ sudo lsof | grep Backups
lsof: WARNING: can't stat() zfs file system /array/Backups
      Output information may be incomplete.
lsof: WARNING: can't stat() zfs file system /array/Backups/gwen
      Output information may be incomplete.

fuser认为挂载不存在

topher@nzxt:~$ sudo fuser -vm /array/Backups
Specified filename /array/Backups does not exist.
topher@nzxt:~$ sudo fuser -vm /array/Backups/gwen
Specified filename /array/Backups/gwen does not exist.

Answer 1

尝试懒散或强制的umount，看看会发生什么？

umount -l或umount -f

见：https://github.com/openzfs/zfs/issues/2435和Linux挂载点无论如何都不能卸载？