dht/rebalancer: Marking tiering migration fops

This is a follow up patch for http://review.gluster.org/#/c/10080
In the above, the suggested change in
http://review.gluster.org/#/c/10080/7/xlators/cluster/dht/src/dht-rebalance.c
doesnot work. The reason it doesnt work is promotion and demotion are done in
a multithread way. Whenever a promotion or demotion thread is called, the frame
of the old sync_op thread is not carried with it. As a result the frame->root->pid
is not set.

Solution:
When the file is getting migrated, we get a tiering.migration key_value in the
xattr dict, so that we pass  this dic key-value when we do syncop_setxattr()
to do  data migration and set the frame->root->pid GF_CLIENT_PID_TIER_DEFRAG
in dht_setxattr() just before calling dht_start_rebalance_task().

Change-Id: I86fef2d961b32fdd2c0c69d8512cbe846b393404
BUG: 1194753
Signed-off-by: Joseph Fernandes <josferna@redhat.com>
Reviewed-on: http://review.gluster.org/10266
Reviewed-by: Shyamsundar Ranganathan <srangana@redhat.com>
Reviewed-by: Susant Palai <spalai@redhat.com>
Reviewed-by: Dan Lambright <dlambrig@redhat.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>

3 files changed, 34 insertions, 6 deletions

diff --git a/xlators/cluster/dht/src/dht-common.c b/xlators/cluster/dht/src/dht-common.c
index 12a283bd991..c26100c84fa 100644
--- a/xlators/cluster/dht/src/dht-common.c
+++ b/xlators/cluster/dht/src/dht-common.c
@@ -3431,6 +3431,21 @@ dht_setxattr (call_frame_t *frame, xlator_t *this,
                 if (local->rebalance.target_node) {
                         local->flags = forced_rebalance;
 
+                        /* Flag to suggest its a tiering migration
+                         * The reason for this dic key-value is that
+                         * promotions and demotions are multithreaded
+                         * so the original frame from gf_defrag_start()
+                         * is not carried. A new frame will be created when
+                         * we do syncop_setxattr(). This doesnot have the
+                         * frame->root->pid of the original frame. So we pass
+                         * this dic key-value when we do syncop_setxattr() to do
+                         * data migration and set the frame->root->pid to
+                         * GF_CLIENT_PID_TIER_DEFRAG in dht_setxattr() just before
+                         * calling dht_start_rebalance_task() */
+                        tmp = dict_get (xattr, "tiering.migration");
+                        if (tmp)
+                                frame->root->pid = GF_CLIENT_PID_TIER_DEFRAG;
+
                         ret = dht_start_rebalance_task (this, frame);
                         if (!ret)
                                 return 0;
diff --git a/xlators/cluster/dht/src/dht-rebalance.c b/xlators/cluster/dht/src/dht-rebalance.c
index 52f91946240..d471a71db89 100644
--- a/xlators/cluster/dht/src/dht-rebalance.c
+++ b/xlators/cluster/dht/src/dht-rebalance.c
@@ -2718,12 +2718,7 @@ gf_defrag_start (void *data)
         if (!frame)
                 goto out;
 
-        /* If its a tiering rebalancer mark it seperately so that CTR Xlator
-         * can take appropriate action */
-        if (defrag->cmd == GF_DEFRAG_CMD_START_TIER)
-                frame->root->pid = GF_CLIENT_PID_TIER_DEFRAG;
-        else
-                frame->root->pid = GF_CLIENT_PID_DEFRAG;
+        frame->root->pid = GF_CLIENT_PID_DEFRAG;
 
         defrag->pid = frame->root->pid;
 
diff --git a/xlators/cluster/dht/src/tier.c b/xlators/cluster/dht/src/tier.c
index 8180d77787d..3e3fad7ca26 100644
--- a/xlators/cluster/dht/src/tier.c
+++ b/xlators/cluster/dht/src/tier.c
@@ -219,6 +219,24 @@ tier_migrate_using_query_file (void *_args)
                         if (per_file_status) {
                                 goto per_file_out;
                         }
+
+                        /* Flag to suggest its a tiering migration
+                         * The reason for this dic key-value is that
+                         * promotions and demotions are multithreaded
+                         * so the original frame from gf_defrag_start()
+                         * is not carried. A new frame will be created when
+                         * we do syncop_setxattr(). This doesnot have the
+                         * frame->root->pid of the original frame. So we pass
+                         * this dic key-value when we do syncop_setxattr() to do
+                         * data migration and set the frame->root->pid to
+                         * GF_CLIENT_PID_TIER_DEFRAG in dht_setxattr() just before
+                         * calling dht_start_rebalance_task() */
+                        per_file_status = dict_set_str (migrate_data,
+                                                "tiering.migration", "yes");
+                        if (per_file_status) {
+                                goto per_file_out;
+                        }
+
                 }
                 per_link_status = 0;
                 /* Per link of file */