NFSv4 file deletion fails with "Device or resource busy" error on RHEL systems.

Issue

• Getting "Device or resource busy" error, while attempting to remove a file, present on a NFS share; Although the file is not in use, by the concerned client:

  # rm -f /path/to/file/on/a/nfs/share
  rm: cannot remove '/path/to/file/on/a/nfs/share': Device or resource busy
  

• Why am I seeing a "Device or resource busy" error when trying to delete a file? Could it be that another NFS client has the file open? I have already checked that the file is not in use, using lsof and fuser on the affected client.

• A packet capture while removing the file, shows NFS4ERR_FILE_OPEN error, even though no processes on the current NFS client have the file open.

• Could NFSv4 be blocking deletion due to an open file on another client?

• Is NFSv4 preventing the file deletion because it’s open on another client? How can I check for active locks?