glusterd: Stop/restart/notify to daemons(svcs) during reset/set on a volume

problem : Reset/set commands were not working properly. reset command returns
success but it not sending notification to svcs if corresponding graph modified.

Fix: Whenever reset/set command issued, generate the temp graph and compare
with original graph and do the fallowing actions
1.) If both graph are identical nothing to do with svcs.
2.) If any changes in graph topology restart/stop service by calling
svc manager.
3)  If changes in options send notify signal by calling glusterd_fetchspec_notify.

Back port of:
>Change-Id: I852c4602eafed1ae6e6a02424814fe3a83e3d4c7
>BUG: 1209329
>Signed-off-by: anand <anekkunt@redhat.com>
>Reviewed-on: http://review.gluster.org/10850
>Tested-by: NetBSD Build System <jenkins@build.gluster.org>
>Tested-by: Gluster Build System <jenkins@build.gluster.com>
>Reviewed-by: Atin Mukherjee <amukherj@redhat.com>
>(cherry picked from commit 7255febab2c38cc89b71f2519a20d10f53586000)

Change-Id: I42aa757ecc6b5b307b5927d11f12d08f57ac0ae2
BUG: 1253165
Reviewed-on: http://review.gluster.org/11905
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Tested-by: NetBSD Build System <jenkins@build.gluster.org>
Reviewed-by: Atin Mukherjee <amukherj@redhat.com>

1 files changed, 65 insertions, 1 deletions

diff --git a/xlators/mgmt/glusterd/src/glusterd-shd-svc.c b/xlators/mgmt/glusterd/src/glusterd-shd-svc.c
index f9f41898b39..0e664b5c786 100644
--- a/xlators/mgmt/glusterd/src/glusterd-shd-svc.c
+++ b/xlators/mgmt/glusterd/src/glusterd-shd-svc.c
@@ -15,6 +15,7 @@
 #include "glusterd-volgen.h"
 #include "glusterd-svc-mgmt.h"
 #include "glusterd-shd-svc.h"
+#include "glusterd-svc-helper.h"
 
 char *shd_svc_name = "glustershd";
 
@@ -182,5 +183,68 @@ out:
 int
 glusterd_shdsvc_reconfigure ()
 {
-        return glusterd_svc_reconfigure (glusterd_shdsvc_create_volfile);
+        int              ret             = -1;
+        xlator_t        *this            = NULL;
+        glusterd_conf_t *priv            = NULL;
+        gf_boolean_t     identical       = _gf_false;
+
+        this = THIS;
+        GF_VALIDATE_OR_GOTO (this->name, this, out);
+
+        priv = this->private;
+        GF_VALIDATE_OR_GOTO (this->name, priv, out);
+
+        if (glusterd_all_shd_compatible_volumes_stopped ())
+                goto manager;
+
+        /*
+         * Check both OLD and NEW volfiles, if they are SAME by size
+         * and cksum i.e. "character-by-character". If YES, then
+         * NOTHING has been changed, just return.
+         */
+        ret = glusterd_svc_check_volfile_identical (priv->shd_svc.name,
+                                                    build_shd_graph,
+                                                    &identical);
+        if (ret)
+                goto out;
+
+        if (identical) {
+                ret = 0;
+                goto out;
+        }
+
+        /*
+         * They are not identical. Find out if the topology is changed
+         * OR just the volume options. If just the options which got
+         * changed, then inform the xlator to reconfigure the options.
+         */
+        identical = _gf_false; /* RESET the FLAG */
+        ret = glusterd_svc_check_topology_identical (priv->shd_svc.name,
+                                                     build_shd_graph,
+                                                     &identical);
+        if (ret)
+                goto out;
+
+        /* Topology is not changed, but just the options. But write the
+         * options to shd volfile, so that shd will be reconfigured.
+         */
+        if (identical) {
+                ret = glusterd_shdsvc_create_volfile ();
+                if (ret == 0) {/* Only if above PASSES */
+                        ret = glusterd_fetchspec_notify (THIS);
+                }
+                goto out;
+        }
+manager:
+        /*
+         * shd volfile's topology has been changed. shd server needs
+         * to be RESTARTED to ACT on the changed volfile.
+         */
+        ret = priv->shd_svc.manager (&(priv->shd_svc), NULL,
+                                     PROC_START_NO_WAIT);
+
+out:
+        gf_msg_debug (this->name, 0, "Returning %d", ret);
+        return ret;
+
 }