Description of problem:
Tried to rename a directory and it failed. 
issue is basically seen when quota related available space is 1GB or less. 


Version-Release number of selected component (if applicable):
glusterfs-3.6.0.28-1.el6rhs.x86_64

How reproducible:
always

Steps to Reproduce:
1. create a volume of 6x2 type, start it
2. enable quota
3. set limit of 20GB on "/"
4. create data upto 19GB (approx) after mounting volume over nfs. include some dir creation also.
5. rename some directory.

Actual results:
[root@rhsauto002 nfs-test]# mv dir3 dir3-rename
mv: cannot move ‘dir3’ to ‘dir3-rename’: Disk quota exceeded
[root@rhsauto002 nfs-test]# 
[root@rhsauto002 nfs-test]# 
[root@rhsauto002 nfs-test]# ls
dir1  dir2  dir3  dir4  run16165  run27343  run32188  tests.init
[root@rhsauto002 nfs-test]# 
[root@rhsauto002 nfs-test]# 
[root@rhsauto002 nfs-test]# df -h /mnt/nfs-test
Filesystem             Size  Used Avail Use% Mounted on
10.70.37.156:dist-rep   20G   19G  1.3G  94% /mnt/nfs-test



Expected results:

rename should work.

Additional info:
works in case if I delete around 5GB of data.
[root@rhsauto002 dir3]# rm -rf *
[root@rhsauto002 dir3]# ls
[root@rhsauto002 dir3]# 
[root@rhsauto002 dir3]# 
[root@rhsauto002 dir3]# df -h /mnt/nfs-test
Filesystem             Size  Used Avail Use% Mounted on
10.70.37.156:dist-rep   20G   14G  6.3G  69% /mnt/nfs-test
[root@rhsauto002 dir3]# 
[root@rhsauto002 dir3]# 
[root@rhsauto002 dir3]# 
[root@rhsauto002 dir3]# cd ..
[root@rhsauto002 nfs-test]# ls
dir1  dir2  dir3  dir4  run16165  run27343  run32188  tests.init
[root@rhsauto002 nfs-test]# mv dir3 dir3-rename