anchor.diff:  There are some limitations for this feature:
   
   =====
  -If we enable this feature, some master operations such as grant, revoke, snapshot... (See the design doc for more details) will be slower as we need to sync HDFS ACLs to related hfiles.
  +If we enable this feature, some master operations such as grant, revoke, snapshot...
  +(See the design doc for more details) will be slower as we need to sync HDFS ACLs to related hfiles.
   =====
   
   =====
  
positive.code: ====
  
  === Permission to access snapshot and data files
  Generally, only the HBase owner or the HDFS admin have the permission to access hfiles.
  
  link:https://issues.apache.org/jira/browse/HBASE-18659[HBASE-18659] use HDFS ACLs to make HBase granted user have the permission to access the snapshot files.
  
  ==== HDFS ACLs
  
  HDFS ACLs supports an "access ACL", which defines the rules to enforce during permission checks, and a "default ACL", which defines the ACL entries that new child files or sub-directories receive automatically during creation.
  By HDFS ACLs, HBase sync granted users with read permission to files.
  
  ==== Basic idea
  
  
negative.code:  * {hbase-rootdir}/archive/data/{namespace}/{table}
   * {hbase-rootdir}/.hbase-snapshot/{snapshotName}
  
  So the basic idea is to add or remove HDFS ACLs to files of
  global/namespace/table directory when grant or revoke permission to global/namespace/table.
  
  See the design doc in link:https://issues.apache.org/jira/browse/HBASE-18659[HBASE-18659] for more details.
  
  