今天在操作移动硬盘挂载服务器时，执行完mount指令，直接报错“Mount is denied because the NTFS volume is already exclusively opened.
The volume may be already mounted, or another software may use it which
could be identified for example by the help of the 'fuser' command.”
root@dell-PowerEdge-T430:/home# mount -t ntfs-3g /dev/sdc1 /home/upan
Mount is denied because the NTFS volume is already exclusively opened.
The volume may be already mounted, or another software may use it which
could be identified for example by the help of the 'fuser' command.翻译下：“拒绝挂载，因为NTFS卷已经独占地打开了。卷可能已经挂载，或其他软件可能使用它
可以通过'fuser'命令的帮助来识别。”
原因：回想了下，应该是非正常umount操作，可能是直接拔出USB，或者服务器重启造成的。
根据报错提示，我们可以通过fuser指令，来查看打开文件的信息。那就查下fuser的如何使用，执行
fuser --hlep
root@dell-PowerEdge-T430:/home# fuser --help
fuser: Invalid option --help
Usage: fuser [-fMuvw] [-a|-s] [-4|-6] [-c|-m|-n SPACE] [-k [-i] [-SIGNAL]] NAME...
fuser -l
fuser -V
Show which processes use the named files, sockets, or filesystems.
-a,--all display unused files too
-i,--interactive ask before killing (ignored without -k)
-k,--kill kill processes accessing the named file
-l,--list-signals list available signal names
-m,--mount show all processes using the named filesystems or block device
-M,--ismountpoint fulfill request only if NAME is a mount point
-n,--namespace SPACE search in this name space (file, udp, or tcp)
-s,--silent silent operation
-SIGNAL send this signal instead of SIGKILL
-u,--user display user IDs
-v,--verbose verbose output
-w,--writeonly kill only processes with write access
-V,--version display version information
-4,--ipv4 search IPv4 sockets only
-6,--ipv6 search IPv6 sockets only
- reset options
udp/tcp names: [local_port][,[rmt_host][,[rmt_port]]]查询全部信息
root@dell-PowerEdge-T430:/home# fuser -a /dev/sdc1
/dev/sdc1: 3774有点少啊，就一个文件路径和进程号，直接执行kill，关闭当前打开的进程。
root@dell-PowerEdge-T430:/home# fuser -k /dev/sdc1
/dev/sdc1: 3774再次查询
root@dell-PowerEdge-T430:/home# fuser -a /dev/sdc1
/dev/sdc1:进程已经关闭了。
重新执行mount挂载指令即可。