Description of problem:
=======================
After the quota limit is execeeded instead of "disk quota exceeded" message, it throws out Input/Output error. Can delete the file even.

[root@dhcp37-61 fuse1]# dd if=/dev/urandom of=testfile1 bs=128k count=10240
dd: writing `testfile1': Input/output error
dd: closing output file `testfile1': Input/output error
[root@dhcp37-61 fuse1]# rm -f testfile1 
rm: cannot remove `testfile1': Input/output error
[root@dhcp37-61 fuse1]# 

Version-Release number of selected component (if applicable):
=============================================================
[root@dhcp37-164 ~]# gluster --version
glusterfs 3.7dev built on Apr  1 2015 01:04:00
Repository revision: git://git.gluster.com/glusterfs.git
Copyright (c) 2006-2011 Gluster Inc. <http://www.gluster.com>
GlusterFS comes with ABSOLUTELY NO WARRANTY.
You may redistribute copies of GlusterFS under the terms of the GNU General Public License.
[root@dhcp37-164 ~]# 

How reproducible:
=================
100%

Steps to Reproduce:
1. Create a disperse volume 1x(4+2)
2. set the quota limit to 1GB 
3. Create a file from mount exceeding 1GB

Actual results:
===============
Input / Output error

Expected results:
=================
Disk quota exceeded should be seen

Additional info:
================
Sosreports will be attached.