tier/detach: Clear tier-fix-layout-complete xattr after migration threads join

Previously we had wrongly placed the clearing tier-fix-layout-complete
xattr before the joining of migration threads. This would lead to
situations where failure of clearing the xattr would cause the
premature death of migration threads.

Now we clear the xattr only after the data movement threads join,
ensuring that all migration is done.

This is a backport of 14285

> Change-Id: I829b671efa165ae13dbff7b00707434970b37a09
> BUG: 1334839
> Signed-off-by: Joseph Fernandes <josferna@redhat.com>
Signed-off-by: Dan Lambright <dlambrig@redhat.com>

Change-Id: I08cc92db1fb8d48026ca51743be6cafe385d1b79
BUG: 1336152
Reviewed-on: http://review.gluster.org/14342
Smoke: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Joseph Fernandes
Tested-by: Dan Lambright <dlambrig@redhat.com>
NetBSD-regression: NetBSD Build System <jenkins@build.gluster.org>
CentOS-regression: Gluster Build System <jenkins@build.gluster.com>

1 files changed, 42 insertions, 33 deletions

diff --git a/xlators/cluster/dht/src/dht-rebalance.c b/xlators/cluster/dht/src/dht-rebalance.c
index 0a84f2a74c2..bf27e476c72 100644
--- a/xlators/cluster/dht/src/dht-rebalance.c
+++ b/xlators/cluster/dht/src/dht-rebalance.c
@@ -3385,39 +3385,45 @@ out:
         return ret;
 }
 
-int
+void
 gf_tier_clear_fix_layout (xlator_t *this, loc_t *loc, gf_defrag_info_t *defrag)
 {
         int ret         = -1;
         dict_t *dict    = NULL;
 
-        /* Check if background fixlayout is completed. */
+        GF_VALIDATE_OR_GOTO ("tier", this, out);
+        GF_VALIDATE_OR_GOTO (this->name, loc, out);
+        GF_VALIDATE_OR_GOTO (this->name, defrag, out);
+
+        /* Check if background fixlayout is completed. This is not
+         * multi-process safe i.e there is a possibility that by the time
+         * we move to remove the xattr there it might have been cleared by some
+         * other detach process from other node. We ignore the error if such
+         * a thing happens */
         ret = syncop_getxattr (this, loc, &dict,
                         GF_XATTR_TIER_LAYOUT_FIXED_KEY, NULL, NULL);
         if (ret) {
                 /* Background fixlayout not complete - nothing to clear*/
-                gf_log (this->name, GF_LOG_WARNING,
+                gf_msg (this->name, GF_LOG_WARNING, -ret,
+                        DHT_MSG_LOG_TIER_STATUS,
                         "Unable to retrieve fixlayout xattr."
                         "Assume background fix layout not complete");
-                ret = 0;
                 goto out;
         }
 
         ret = syncop_removexattr (this, loc, GF_XATTR_TIER_LAYOUT_FIXED_KEY,
                                   NULL, NULL);
         if (ret) {
-                gf_log (this->name, GF_LOG_WARNING,
+                gf_msg (this->name, GF_LOG_WARNING, -ret,
+                        DHT_MSG_LOG_TIER_STATUS,
                         "Failed removing tier fix layout "
                         "xattr from %s", loc->path);
-                defrag->total_failures++;
-                ret = -1;
                 goto out;
         }
         ret = 0;
 out:
         if (dict)
                 dict_unref (dict);
-        return ret;
 }
 
 void
@@ -3434,24 +3440,25 @@ gf_tier_wait_fix_lookup (gf_defrag_info_t *defrag) {
 int
 gf_defrag_start_crawl (void *data)
 {
-        xlator_t                *this           = NULL;
-        dht_conf_t              *conf           = NULL;
-        gf_defrag_info_t        *defrag         = NULL;
-        int                      ret            = -1;
-        loc_t                    loc            = {0,};
-        struct iatt              iatt           = {0,};
-        struct iatt              parent         = {0,};
-        dict_t                  *fix_layout     = NULL;
-        dict_t                  *migrate_data   = NULL;
-        dict_t                  *status         = NULL;
-        dict_t                  *dict           = NULL;
-        glusterfs_ctx_t         *ctx            = NULL;
-        dht_methods_t           *methods        = NULL;
-        int                      i              = 0;
-        int                     thread_index    = 0;
-        int                     err             = 0;
-        int                     thread_spawn_count = 0;
+        xlator_t                *this                   = NULL;
+        dht_conf_t              *conf                   = NULL;
+        gf_defrag_info_t        *defrag                 = NULL;
+        int                      ret                    = -1;
+        loc_t                    loc                    = {0,};
+        struct iatt              iatt                   = {0,};
+        struct iatt              parent                 = {0,};
+        dict_t                  *fix_layout             = NULL;
+        dict_t                  *migrate_data           = NULL;
+        dict_t                  *status                 = NULL;
+        dict_t                  *dict                   = NULL;
+        glusterfs_ctx_t         *ctx                    = NULL;
+        dht_methods_t           *methods                = NULL;
+        int                      i                      = 0;
+        int                     thread_index            = 0;
+        int                     err                     = 0;
+        int                     thread_spawn_count      = 0;
         pthread_t tid[MAX_MIGRATOR_THREAD_COUNT];
+        gf_boolean_t            is_tier_detach          = _gf_false;
 
         this = data;
         if (!this)
@@ -3656,14 +3663,9 @@ gf_defrag_start_crawl (void *data)
                         goto out;
                 }
 
-                if (defrag->cmd == GF_DEFRAG_CMD_START_DETACH_TIER) {
-                        /* If its was a detach remove the tier fix-layout
-                         * xattr on root */
-                         ret = gf_tier_clear_fix_layout (this, &loc, defrag);
-                         if (ret) {
-                                goto out;
-                         }
-                }
+                if (defrag->cmd == GF_DEFRAG_CMD_START_DETACH_TIER)
+                        is_tier_detach = _gf_true;
+
         }
 
         gf_log ("DHT", GF_LOG_INFO, "crawling file-system completed");
@@ -3699,6 +3701,12 @@ out:
                  gf_tier_wait_fix_lookup (defrag);
         }
 
+        if (is_tier_detach && ret == 0) {
+                /* If it was a detach remove the tier fix-layout
+                * xattr on root. Ignoring the failure, as nothing has to be
+                * done, logging is done in gf_tier_clear_fix_layout */
+                gf_tier_clear_fix_layout (this, &loc, defrag);
+        }
 
         if (defrag->queue) {
                 gf_dirent_free (defrag->queue[0].df_entry);
@@ -3738,6 +3746,7 @@ exit:
 }
 
 
+
 static int
 gf_defrag_done  (int ret, call_frame_t *sync_frame, void *data)
 {