docker "There are no more loopback devices available" Error

ERROR :

[root@Host]# /usr/bin/dockerd
INFO[0000] libcontainerd: new containerd process, pid: 17484
WARN[0000] containerd: low RLIMIT_NOFILE changing to max  current=1024 max=4096
ERRO[0001] There are no more loopback devices available.
ERRO[0001] [graphdriver] prior storage driver "devicemapper" failed: loopback attach failed
FATA[0001] Error starting daemon: error initializing graphdriver: loopback attach failed

[root@Host]# systemctl status docker
● docker.service - Docker Application Container Engine
   Loaded: loaded (/usr/lib/systemd/system/docker.service; disabled; vendor preset: disabled)
   Active: failed (Result: exit-code) since Fri 2016-08-19 11:03:50 KST; 3min 58s ago
     Docs: https://docs.docker.com
  Process: 15458 ExecStart=/usr/bin/dockerd (code=exited, status=1/FAILURE)
 Main PID: 15458 (code=exited, status=1/FAILURE)
   Memory: 0B
   CGroup: /system.slice/docker.service

Aug 19 11:03:49 Host systemd[1]: Starting Docker Application Container Engine...
Aug 19 11:03:49 Host dockerd[15458]: time="2016-08-19T11:03:49.625450019+09:00" level=...70"
Aug 19 11:03:50 Host dockerd[15458]: time="2016-08-19T11:03:50.631640761+09:00" level=...e."
Aug 19 11:03:50 Host dockerd[15458]: time="2016-08-19T11:03:50.631709945+09:00" level=...ed"
Aug 19 11:03:50 Host dockerd[15458]: time="2016-08-19T11:03:50.631809834+09:00" level=...ed"
Aug 19 11:03:50 Host systemd[1]: docker.service: main process exited, code=exited, sta...URE
Aug 19 11:03:50 Host systemd[1]: Failed to start Docker Application Container Engine.
Aug 19 11:03:50 Host systemd[1]: Unit docker.service entered failed state.
Aug 19 11:03:50 Host systemd[1]: docker.service failed.

Solution :

#!/bin/bash for i in {0..6} do mknod -m0660 /dev/loop$i b 7 $i done