Tested with build glusterfs-3.7.5-7.el6rhs.x86_64:
Created 2x2 volume and exported the samba share on windows client.
Executed the perl script mentioned in bug description which creates nested folders and files.
Executed add-brick operation while i/o's are going on.
Executed rebalance.
Mount point is still accessible and there are no I/O errors on windows client.
Marking the BZ verified.
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://rhn.redhat.com/errata/RHBA-2016-0193.html