mount: /dev/sdb1 already mounted or /mnt busy
[root@]# mount -t ext3 /dev/sdb1 /mnt
mount: /dev/sdb1 already mounted or /mnt busy
lsof didn’t provide any open files that might be linked to this problem or there was any “famd” running. Finally doing the following steps to remove the logical devices from the device-mapper driver helped us fix the problem.
[root@]# dmsetup ls
ddf1_44656c6c202020201028001510281f033832b7a2f6678dab (253, 0)
ddf1_44656c6c202020201028001510281f033832b7a2f6678dab1 (253, 1)
[root@]# dmsetup remove ddf1_44656c6c202020201028001510281f033832b7a2f6678dab1
[root@]# dmsetup ls
ddf1_44656c6c202020201028001510281f033832b7a2f6678dab (253, 0)
[root@]# dmsetup remove ddf1_44656c6c202020201028001510281f033832b7a2f6678dab
[root@]# dmsetup ls
No devices found
