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().

>    http://review.gluster.org/#/c/10266/
>    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>

Change-Id: I6ab42b2c7a3c3e21c461d097b7558ee967b62c62
BUG: 1218959
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>
Signed-off-by: Joseph Fernandes <josferna@redhat.com>
Reviewed-on: http://review.gluster.org/10601
Reviewed-by: Vijay Bellur <vbellur@redhat.com>

1 files changed, 15 insertions, 0 deletions

diff --git a/xlators/cluster/dht/src/dht-common.c b/xlators/cluster/dht/src/dht-common.c
index 2122839c020..e9eec37e6e4 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;