geo-rep: use cold tier bricks for namespace operations

Problem:
symlinks are not getting synced to slave in a Tiering based volume.

Solution:
Now, symlinks are created directly in cold tier bricks( in the backend).

Earlier, cold tier was avoided for namespace operations and only
hot tier was used while processing changelogs.

Now, cold tier is HASH subvolume in a Tiering volume.
So, carry out namespace operation only in cold tier subvolume and
avoid hot tier subvolume to avoid any races.

Earlier, XSYNC was used(and changeloghistory avoided) during initial sync
in order to avoid race while processing historychangelog in Hot tier.
This is no longer required as there is no race from Hot tier.

Also, avoid both live and history changelog ENTRY operations from Hot tier
to avoid any race with cold tier.

Change-Id: Ia8fbb7ae037f5b6cb683f36c0df5c3fc2894636e
BUG: 1288027
Signed-off-by: Saravanakumar Arumugam <sarumuga@redhat.com>
Reviewed-on: http://review.gluster.org/12844
Tested-by: NetBSD Build System <jenkins@build.gluster.org>
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Kotresh HR <khiremat@redhat.com>
Reviewed-by: Venky Shankar <vshankar@redhat.com>
(cherry picked from commit 93f31189ce8f6e2980a39b02568ed17088e0a667)
Reviewed-on: http://review.gluster.org/12891

4 files changed, 13 insertions, 17 deletions

diff --git a/geo-replication/syncdaemon/gsyncd.py b/geo-replication/syncdaemon/gsyncd.py
index ef6db744e46..759052ec153 100644
--- a/geo-replication/syncdaemon/gsyncd.py
+++ b/geo-replication/syncdaemon/gsyncd.py
@@ -358,7 +358,7 @@ def main_i():
                   action='callback', callback=store_local_curry('canon'))
     op.add_option('--canonicalize-escape-url', dest='url_print',
                   action='callback', callback=store_local_curry('canon_esc'))
-    op.add_option('--is-coldtier', default=False, action='store_true')
+    op.add_option('--is-hottier', default=False, action='store_true')
 
     tunables = [norm(o.get_opt_string()[2:])
                 for o in op.option_list
diff --git a/geo-replication/syncdaemon/master.py b/geo-replication/syncdaemon/master.py
index eadf51d3e5b..38b9d9c9fc9 100644
--- a/geo-replication/syncdaemon/master.py
+++ b/geo-replication/syncdaemon/master.py
@@ -828,10 +828,11 @@ class GMasterChangelogMixin(GMasterCommon):
             et = e[self.IDX_START:self.IDX_END]   # entry type
             ec = e[self.IDX_END:].split(' ')      # rest of the bits
 
-            # skip ENTRY operation if cold tier brick
-            if self.name == 'live_changelog':
-                if boolify(gconf.is_coldtier) and et == self.TYPE_ENTRY:
-                    logging.debug('skip ENTRY op: %s if cold tier brick'
+            # skip ENTRY operation if hot tier brick
+            if self.name == 'live_changelog' or \
+                self.name == 'history_changelog':
+                if boolify(gconf.is_hottier) and et == self.TYPE_ENTRY:
+                    logging.debug('skip ENTRY op: %s if hot tier brick'
                                   % (ec[self.POS_TYPE]))
                     continue
 
diff --git a/geo-replication/syncdaemon/monitor.py b/geo-replication/syncdaemon/monitor.py
index 5a6bf5033a4..cfffe9f88bd 100644
--- a/geo-replication/syncdaemon/monitor.py
+++ b/geo-replication/syncdaemon/monitor.py
@@ -99,9 +99,9 @@ class Volinfo(object):
     def get(self, elem):
         return self.tree.findall('.//' + elem)
 
-    def is_cold(self, brickpath):
+    def is_hot(self, brickpath):
         logging.debug('brickpath: ' + repr(brickpath))
-        return brickpath in self.cold_bricks
+        return brickpath in self.hot_bricks
 
     @property
     @memoize
@@ -133,8 +133,8 @@ class Volinfo(object):
 
     @property
     @memoize
-    def cold_bricks(self):
-        return [b.text for b in self.get('coldBricks/brick')]
+    def hot_bricks(self):
+        return [b.text for b in self.get('hotBricks/brick')]
 
 class Monitor(object):
 
@@ -269,7 +269,7 @@ class Monitor(object):
                                                  ','.join([str(rw), str(ww),
                                                            str(ra), str(wa)]),
                                                  '--subvol-num', str(w[2])] +
-                         (['--is-coldtier'] if w[3] else []) +
+                         (['--is-hottier'] if w[3] else []) +
                          ['--resource-remote', remote_host])
 
             cpids.add(cpid)
@@ -420,7 +420,7 @@ def distribute(*resources):
 
     workerspex = [(brick['dir'], slaves[idx % len(slaves)],
                   get_subvol_num(idx, mvol.replica_count, mvol.disperse_count),
-                  mvol.is_cold(":".join([brick['host'], brick['dir']])))
+                  mvol.is_hot(":".join([brick['host'], brick['dir']])))
                   for idx, brick in enumerate(mvol.bricks)
                   if is_host_local(brick['host'])]
     logging.info('worker specs: ' + repr(workerspex))
diff --git a/geo-replication/syncdaemon/resource.py b/geo-replication/syncdaemon/resource.py
index 1b50caba01a..0573acce3e7 100644
--- a/geo-replication/syncdaemon/resource.py
+++ b/geo-replication/syncdaemon/resource.py
@@ -1434,12 +1434,7 @@ class GLUSTER(AbstractUrl, SlaveLocal, SlaveRemote):
             # Note: if config.change_detector is xsync then
             # it will not use changelog history api
             try:
-                # if cold brick type, avoid changeloghistory and use xsync
-                if (boolify(gconf.is_coldtier)):
-                        logging.info("cold tier using xsync crawl")
-                        g1.crawlwrap(oneshot=True)
-                else:
-                        g3.crawlwrap(oneshot=True)
+                g3.crawlwrap(oneshot=True)
             except PartialHistoryAvailable as e:
                 logging.info('Partial history available, using xsync crawl'
                              ' after consuming history till %s' % str(e))