Description of problem:
=======================
Seeing below assertion failed errors in rebalance logs when rebalance is running,
Assertion failed: ec_get_inode_size(fop, fop->locks[0].lock->loc.inode, &cbk->iatt[0].ia_size) errors in rebalance logs

Version-Release number of selected component (if applicable):
3.12.2-7.el7rhgs.x86_64

How reproducible:
1/1

Steps to Reproduce:
===================
1) Create Distributed-Disperse volume and start it.
2) FUSE mount it on multiple clients
3) From clients start below operations,
Create two dirs 1 and 2 on the mount point.
Client-1: Linux kernel untar --> tar -xvf linux-4.9.27.tar.gz -C 1
Client-2: Linux kernel untar --> tar -xvf linux-4.9.27.tar.gz -C 2
Client-3: while true; do ls -lRt;done
Client-4: while true; do find . |xargs stat ;done
4) Now add-bricks and trigger rebalance without force option.
5) Wait till the rebalance completes. 

Actual results:
===============
Seeing below assertion failed errors in rebalance logs,
Assertion failed: ec_get_inode_size(fop, fop->locks[0].lock->loc.inode, &cbk->iatt[0].ia_size) errors in rebalance logs

Expected results:
=================
No assertions in rebalance logs.