cluster/afr: Return the list of node_uuids for the subvolume

Problem:
AFR was returning the node uuid of the first node for every file if
the replica set was healthy, which was resulting in only one node
migrating all the files.

Fix:
With this patch AFR returns the list of node_uuids to the upper layer,
so that they can decide on which node to migrate which files, resulting
in improved performance. Ordering of node uuids will be maintained based
on the ordering of the bricks. If a brick is down, then the node uuid
for that will be set to all zeros.

Change-Id: I73ee0f9898ae473584fdf487a2980d7a6db22f31
BUG: 1366817
Signed-off-by: karthik-us <ksubrahm@redhat.com>
Reviewed-on: https://review.gluster.org/17084
Reviewed-by: Pranith Kumar Karampuri <pkarampu@redhat.com>
Tested-by: Pranith Kumar Karampuri <pkarampu@redhat.com>
Smoke: Gluster Build System <jenkins@build.gluster.org>
NetBSD-regression: NetBSD Build System <jenkins@build.gluster.org>
CentOS-regression: Gluster Build System <jenkins@build.gluster.org>

1 files changed, 49 insertions, 0 deletions

diff --git a/xlators/cluster/afr/src/afr-common.c b/xlators/cluster/afr/src/afr-common.c
index 34d9e56911e..2377419f01c 100644
--- a/xlators/cluster/afr/src/afr-common.c
+++ b/xlators/cluster/afr/src/afr-common.c
@@ -6291,3 +6291,52 @@ mdata_unlock:
         return ret;
 
 }
+
+/*
+ * Concatenates the xattrs in local->replies separated by a delimiter.
+ */
+int
+afr_serialize_xattrs_with_delimiter (call_frame_t *frame, xlator_t *this,
+                                     char *buf, const char *default_str,
+                                     int32_t *serz_len, char delimiter)
+{
+        afr_private_t *priv      = NULL;
+        afr_local_t   *local     = NULL;
+        char          *xattr     = NULL;
+        int            i         = 0;
+        int            len       = 0;
+        int            ret       = -1;
+
+        priv = this->private;
+        local = frame->local;
+
+        for (i = 0; i < priv->child_count; i++) {
+                if (!local->replies[i].valid || local->replies[i].op_ret) {
+                        buf = strncat (buf, default_str, strlen (default_str));
+                        len += strlen (default_str);
+                        buf[len++] = delimiter;
+                        buf[len] = '\0';
+                } else {
+                        ret = dict_get_str (local->replies[i].xattr,
+                                            local->cont.getxattr.name, &xattr);
+                        if (ret) {
+                                gf_msg ("TEST", GF_LOG_ERROR, -ret,
+                                        AFR_MSG_DICT_GET_FAILED,
+                                        "Failed to get the node_uuid of brick "
+                                        "%d", i);
+                                goto out;
+                        }
+                        buf = strncat (buf, xattr, strlen (xattr));
+                        len += strlen (xattr);
+                        buf[len++] = delimiter;
+                        buf[len] = '\0';
+                }
+        }
+        buf[--len] = '\0'; /*remove the last delimiter*/
+        if (serz_len)
+                *serz_len = ++len;
+        ret = 0;
+
+out:
+        return ret;
+}