Unmounting dislocker-file does not release the device file

[VishishtK]

I have an NTFS drive which is mounted on a VM by Libvirt

The first time I attach the drive, it attaches as /dev/vdc
and is mounted by

dislocker /dev/vdc -u password -- decryptPath
mount -t ntfs-3g decryptPath /drives/drive2

It works fine till here but, when I unmount I do

syscall.Unmount(/drives/drive2, 0)
syscall.Unmount(decryptPath +"/dislocker-file", 0)

And it unmounts the dislocker drive
also
ls /dev/vd*
shows that vdc does not exist anymore

After the above steps when I try to attach any other drives
they skip the vdc and go to vdd instead, as if vdc is still occupied by the dislocker drive

Only happens with the dislocker NTFS drive
EXT4 drives work fine