There is a NFS share on the Linux host, and the system show 'device is busy' error when umount NFS share.
The NFS share mount point is /root/fs8.
Step 1 Check if the current path is in the NFS share mount point, please quit from the path if yes.
Step 2 Run the command 'fuser -m -v nfs NFS mount point'to check if there is any other process is using this folder. The result as below picture:
The root cause is that there is another process is using this share point.
Please close the process if there is a process occupied the NFS share mount point when you are umount the NFS share.
You can use this command 'fuser -k NFS share mount point'.