Verified that this works fine on 3.2.0 Async build - glusterfs-3.8.4-18.5. I/O stops for 90 seconds on all clients (v3/v4) and resumes when Grace period gets over.
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://access.redhat.com/errata/RHBA-2017:2339