glusterd: support for tier volumes 'detach start' and 'detach commit'

These commands work in a manner analagous to rebalancing when removing a
brick. The existing migration daemon detects "detach start" and switches
to moving data off the hot tier. While in this state all lookups are
directed to the cold tier.

gluster v detach-tier <vol> start
gluster v detach-tier <vol> commit

The status and stop cli commands shall be submitted separately.

Change-Id: I24fda5cc3ba74f5fb8aa9a3234ad51f18b80a8a0
BUG: 1205540
Signed-off-by: Dan Lambright <dlambrig@redhat.com>
Signed-off-by: root <root@localhost.localdomain>
Signed-off-by: Dan Lambright <dlambrig@redhat.com>
Reviewed-on: http://review.gluster.org/10108
Reviewed-by: Kaleb KEITHLEY <kkeithle@redhat.com>
Tested-by: NetBSD Build System

1 files changed, 24 insertions, 0 deletions

diff --git a/xlators/cluster/dht/src/dht-rebalance.c b/xlators/cluster/dht/src/dht-rebalance.c
index 9f389c12213..98d9b58385d 100644
--- a/xlators/cluster/dht/src/dht-rebalance.c
+++ b/xlators/cluster/dht/src/dht-rebalance.c
@@ -1985,6 +1985,22 @@ gf_defrag_start_crawl (void *data)
                         goto out;
                 }
                 methods->migration_other(this, defrag);
+                if (defrag->cmd == GF_DEFRAG_CMD_START_DETACH_TIER) {
+                        migrate_data = dict_new ();
+                        if (!migrate_data) {
+                                ret = -1;
+                                goto out;
+                        }
+                        ret = dict_set_str (migrate_data,
+                                            GF_XATTR_FILE_MIGRATE_KEY,
+                                            "force");
+                        if (ret)
+                                goto out;
+
+                        ret = gf_defrag_fix_layout (this, defrag, &loc,
+                                                    fix_layout,
+                                                    migrate_data);
+                }
         }
 
         if ((defrag->defrag_status != GF_DEFRAG_STATUS_STOPPED) &&
@@ -2173,6 +2189,14 @@ out:
 }
 
 int
+gf_defrag_start_detach_tier (gf_defrag_info_t *defrag)
+{
+        defrag->cmd = GF_DEFRAG_CMD_START_DETACH_TIER;
+
+        return 0;
+}
+
+int
 gf_defrag_stop (gf_defrag_info_t *defrag, gf_defrag_status_t status,
                 dict_t *output)
 {