Thank you. We managed to clear the broken files by unmounting the drive and running the xfs_repair command on the device. 
Now we have issues with getting the buckets back as they were. The cluster is gone, the nodes are gone, the buckets are gone. The data still exists, but Couchbase doesn’t recognize the data, even if a cluster is made where the data location points straight to the data. Is it possible to salvage this or are we doomed to remake the buckets and re-import everything?
EDIT:
Made a new thread for this issue:
EDIT2: Managed to resolve it by just remaking the buckets. This time it didn’t overwrite and remove all the data, but instead the buckets started slowly filling with the data again.