Bug 1139218

Description of problem:
=======================

In a scenarion where snapshotted volume is mounted on the client and the original mounted is restored. The already mounted snapshotted volume doesn't give "Transport end-point not connected", it still lists the files in read-only.

For example:
============

Snapshoted volume is mounted on a client and data is present on it:
===================================================================

[root@wingo ~]# mount -t glusterfs inception.lab.eng.blr.redhat.com:/snaps/SR1/vol3 /mnt/SR1
[root@wingo ~]# cd /mnt/SR1
[root@wingo SR1]# ls
1   11  13  15  17  19  20  4  6  8  file.1   file.2  file.4  file.6  file.8  nfile.1   nfile.2  nfile.4  nfile.6  nfile.8
10  12  14  16  18  2   3   5  7  9  file.10  file.3  file.5  file.7  file.9  nfile.10  nfile.3  nfile.5  nfile.7  nfile.9
[root@wingo SR1]#

Volume is restored to its snapshot SR1 and started:
===================================================

[root@inception ~]# gluster snapshot restore SR1
Snapshot restore: SR1: Snap restored successfully
[root@inception ~]# gluster v start vol3
volume start: vol3: success
[root@inception ~]# 

Look into the already mounted snapshoted volume SR1:
====================================================

[root@wingo ~]# cd /mnt/SR1
[root@wingo SR1]# ls
1   11  13  15  17  19  20  4  6  8  file.1   file.2  file.4  file.6  file.8  nfile.1   nfile.2  nfile.4  nfile.6  nfile.8
10  12  14  16  18  2   3   5  7  9  file.10  file.3  file.5  file.7  file.9  nfile.10  nfile.3  nfile.5  nfile.7  nfile.9
[root@wingo SR1]#

Even when the volume(vol3) is restored to its snapshot(SR1), the snapshot SR1 is deleted during restore but the already mounted client is able to access it as earlier. From the usability it should be inaccessible. 


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 4 node cluster
2. Create a volume (vol3)
3. Mount the volume to the client (/mnt/vol3)
4. Add some data to the client
5. Create a snapshot of a volume (SR1)
6. Mount the snapshot of the volume to the client (/mnt/SR1). It should be mountable and should be in read-only
7. Stop the volume (vol3)
8. Restore the volume to its snapshot (SR1)
9. Start the volume (vol3)
10. Access the already snapshoted volume (/mnt/SR1)

Actual results:
===============
Able to access the files in read-only mode

Expected results:
=================
When a snapshot is deleted as part of the restore the already snapshoted volume client should error out complaining "Transport end-point not connected" as in real the snapshot SR1 doesn't exist

USS might see a impact as the user who is already monitoring the snapshoted volume after restore will keep see the updated data not the snapshoted data.