Description of problem:

Setting of cluster.read-freq-threshold is not honored. While cluster.read-freq-threshold is set to a value more than 1, files are  promoted even when they are read once.

For the test, cluster.read-freq-threshold was set to 3, and a file from cold tier was accessed by fuse mount once. File got promoted. 

[root@zod /]# gluster vol info
 
Volume Name: krk-vol
Type: Tier
Volume ID: 1cb424ba-8f21-41f7-8d83-6c321d79a15c
Status: Started
Number of Bricks: 10
Transport-type: tcp
Hot Tier :
Hot Tier Type : Distributed-Replicate
Number of Bricks: 2 x 2 = 4
Brick1: yarrow:/rhs/brick7/krk-hot
Brick2: zod:/rhs/brick7/krk-hot
Brick3: yarrow:/rhs/brick6/krk-hot
Brick4: zod:/rhs/brick6/krk-hot
Cold Tier:
Cold Tier Type : Distribute
Number of Bricks: 6
Brick5: zod:/rhs/brick1/krk-vol
Brick6: yarrow:/rhs/brick1/krk-vol
Brick7: zod:/rhs/brick2/krk-vol
Brick8: yarrow:/rhs/brick2/krk-vol
Brick9: zod:/rhs/brick3/krk-vol
Brick10: yarrow:/rhs/brick3/krk-vol
Options Reconfigured:
cluster.write-freq-threshold: 5
cluster.read-freq-threshold: 3
features.record-counters: on
performance.io-cache: off
performance.quick-read: off
features.quota-deem-statfs: on
features.inode-quota: on
features.quota: on
cluster.tier-mode: cache
features.ctr-enabled: on
performance.readdir-ahead: on

Version-Release number of selected component (if applicable):
glusterfs-server-3.7.5-15.el7rhgs.x86_64

How reproducible:
Always

Steps to Reproduce:
1. create a distributed gluster volume
2. create few files
3. attach a hot tier
4. enable quota, turn performance.io-cache and performance.quick-read off
5. configure cluster.read-freq-threshold to a higher value
5. read files that were created earlier in step 2 (cat and vi were used for the test). Read only once.

Actual results:
Files that were read once were promoted

Expected results:
Files should be read at least 'n' number of times to be promoted, where n is the value set for cluster.read-freq-threshold

Additional info:
cluster.write-freq-threshold works as expected