geo-rep: Add data operation if mknod with tier attribute

This is a series of patches which aims to fix geo-replication
in a Tiering Volume.

Problem:
Consider, a file is placed in volume initially and then hot tier is
attached. During any operation on the file, due to lookup a linkto
file is created in hot tier.

Now, any namespace operation carried out on the file is recorded in
both cold and hot tier.
There is a room for races when both changelogs are replayed.

Solution:
So, We are going to replay (namespace related)operations
only in the hot tier.

Why?
a. If the file is directly placed in Hot tier, all fops will be
recorded in HOT tier.

b. If  the file is already present in Cold tier, and if any fop is
carried out, it creates linkto file in Hot tier.
Now, operations like UNLINK, RENAME are captured in Hot tier(by means of linkto file).

This way, we can get both tier's operation in HOT tier itself.

But, We may miss initial Data sync immediately after creating the
file as it is only recording MKNOD. So, if MKNOD encountered
with sticky bit set, queue DATA operation for the corresponding gfid.
(This is addressed here in this patch)

So, If tier-gfid linkto is set, we need to record the corresponding
MKNOD. Earlier this was avoided as it was set as INTERNAL fop.
(This changelog related changes are addressed in the patch:
 - http://review.gluster.org/12417)

Change-Id: I2fa84cfa2b0f86506c3d15d484138ab9651e4f83
BUG: 1266875
Signed-off-by: Saravanakumar Arumugam <sarumuga@redhat.com>
Reviewed-on: http://review.gluster.org/12326
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: Aravinda VK <avishwan@redhat.com>

1 files changed, 9 insertions, 0 deletions

diff --git a/geo-replication/syncdaemon/master.py b/geo-replication/syncdaemon/master.py
index 1bc2450c101..407e4b29580 100644
--- a/geo-replication/syncdaemon/master.py
+++ b/geo-replication/syncdaemon/master.py
@@ -842,6 +842,15 @@ class GMasterChangelogMixin(GMasterCommon):
                     entries.append(edct(ty, gfid=gfid, entry=en,
                                         mode=int(ec[2]),
                                         uid=int(ec[3]), gid=int(ec[4])))
+
+                    # Special case: add DATA in case of tier linkto file,
+                    # Here, we have the assumption that only tier-gfid.linkto
+                    # causes this mknod
+                    if ty in ['MKNOD']:
+                        mode = int(ec[2])
+                        if mode & 01000:
+                            datas.add(os.path.join(pfx, ec[0]))
+
                 elif ty == "RENAME":
                     go = os.path.join(pfx, gfid)
                     st = lstat(go)