Description of problem:
At the moment new stack doesn't populate frame->root->unique in all cases. This makes it difficult to debug hung frames by examining successive state dumps. Fuse and server xlator populate it whenever they can, but other xlators won't be able to assign one when they need to create a new frame/stack. What we need is for unique to be correct. If a stack with same unique is present in successive statedumps, that means the same operation is still in progress. This makes finding hung frames part of debugging hung frames easier.
Version-Release number of selected component (if applicable):
Steps to Reproduce:
REVIEW: https://review.gluster.org/22773 (stack: Make sure to have unique call-stacks in all cases) posted (#1) for review on master by Pranith Kumar Karampuri
REVIEW: https://review.gluster.org/22773 (stack: Make sure to have unique call-stacks in all cases) merged (#4) on master by Amar Tumballi