Mount FREEBSD OK

When I tried to mount a hard drive on FreeBSD today, I got the following error message.
sudo mount -t ufs /dev/da0p2 /mnt/
mount: /dev/da0p2: R/W mount of / denied. Filesystem is not clean - run fsck. Forced mount will invalidate journal contents: Operation not permitted
Here is how to fix it:
sudo mount -r -t ufs /dev/da0p2 /mnt/
where ufs refers to the file system of FreeBSD.
That’s it.
–Derrick



# newfs /dev/da0s1
# mount -t ufs /dev/da0s1 /mnt/usbdisk
# ls -ltr /mnt/usbdisk
total 2
drwxrwxr-x  2 root  operator  512 Nov  6 18:11 .snap

sbr:https://forums.freebsd.org/threads/19087/