If your backup software is using Microsoft VSS to take snapshot of your cluster volumes, sometimes your CSV stuck in redirection access and telling that “Backup in Progress” even if there no running backup at that time..
1- You cannot turn off redirection mode
2- you cannot change owner of volume
3- There is no running backup jobs
Then you may delete the snapshot of the volume in order to bring that volume “Online”
so login to the hyperv node which is the owner of that volume.
Run CMD with elevated privileges.
Enter the volume which backup takes place
Run diskshadow utility
list the volumes which have shadow copies.
DISKSHADOW>LIST SHADOWS ALL
if you are sure about what to delete then you may delete corresponding copy or delete all as you can see below.
DISKSHADOW>DELETE SHADOWS ALL