scripts: prevent running 'showmount' from the start/post hook script

The 31ganesha-start.sh hook script tries to run 'showmount' to see if
the volume that is getting started should get exported by NFS-Ganesha.
It was reported that this caused the 'gluster volume start ...' command
to hang in case rpcbind is not running.

Instead of running 'showmount', we can use DBus to contact NFS-Ganesha
directly, and request the available exports. This will immediately fail
in case NFS-Ganesha is not running.

Cherry picked from commit 2b2294d2a4ef221fccb6eb9f74e9b7dc233b9f1d:
> BUG: 1294446
> Change-Id: I3aba1f86fead67116ca5adb1864a8be626c334fa
> Reported-by: Jeff Darcy <jdarcy@redhat.com>
> Signed-off-by: Niels de Vos <ndevos@redhat.com>
> Reviewed-on: http://review.gluster.org/13098
> Tested-by: Raghavendra Talur <rtalur@redhat.com>
> Reviewed-by: jiffin tony Thottan <jthottan@redhat.com>
> Reviewed-by: Kaleb KEITHLEY <kkeithle@redhat.com>

BUG: 1297862
Change-Id: I3aba1f86fead67116ca5adb1864a8be626c334fa
Signed-off-by: Niels de Vos <ndevos@redhat.com>
Reviewed-on: http://review.gluster.org/13230
Tested-by: NetBSD Build System <jenkins@build.gluster.org>
Reviewed-by: Kaleb KEITHLEY <kkeithle@redhat.com>

2 files changed, 41 insertions, 18 deletions

diff --git a/extras/hook-scripts/start/post/S31ganesha-start.sh b/extras/hook-scripts/start/post/S31ganesha-start.sh
index 9ca07e5a8d6..b85c789b9ed 100755
--- a/extras/hook-scripts/start/post/S31ganesha-start.sh
+++ b/extras/hook-scripts/start/post/S31ganesha-start.sh
@@ -103,23 +103,43 @@ function start_ganesha()
 
 }
 
-        parse_args $@
-        is_exported="no"
-        if showmount -e localhost | cut -d "" -f1 | grep -q "/$VOL[[:space:]]"
-        then
-              is_exported="yes"
-        fi
-        ganesha_value=$(grep $ganesha_key  $GLUSTERD_WORKDIR/vols/$VOL/info |\
-                        cut -d"=" -f2)
-        if [ "$ganesha_value" = "on" -a "$is_exported" = "no" ]
+# based on src/scripts/ganeshactl/Ganesha/export_mgr.py
+function is_exported()
+{
+        local volume="${1}"
+
+        dbus-send --type=method_call --print-reply --system \
+                  --dest=org.ganesha.nfsd /org/ganesha/nfsd/ExportMgr \
+                  org.ganesha.nfsd.exportmgr.ShowExports \
+            | grep -w -q "/${volume}"
+
+        return $?
+}
+
+# Check the info file (contains the volume options) to see if Ganesha is
+# enabled for this volume.
+function ganesha_enabled()
+{
+        local volume="${1}"
+        local info_file="${GLUSTERD_WORKDIR}/vols/${VOL}/info"
+        local enabled="off"
+
+        enabled=$(grep -w ${ganesha_key} ${info_file} | cut -d"=" -f2)
+
+        [ "${enabled}" == "on" ]
+
+        return $?
+}
+
+parse_args $@
+
+if ganesha_enabled ${VOL} && ! is_exported ${VOL}
+then
+        if [ ! -e ${GANESHA_DIR}/exports/export.${VOL}.conf ]
         then
-                if [ ! -e $GANESHA_DIR/exports/export.$VOL.conf ]
-                then
-                        write_conf $VOL > $GANESHA_DIR/exports/export.$VOL.conf
-                fi
-                start_ganesha $VOL
-        else
-                exit 0
+                write_conf ${VOL} > ${GANESHA_DIR}/exports/export.${VOL}.conf
         fi
+        start_ganesha ${VOL}
+fi
 
-
+exit 0
diff --git a/glusterfs.spec.in b/glusterfs.spec.in
index a74bf7f6fed..69195784185 100644
--- a/glusterfs.spec.in
+++ b/glusterfs.spec.in
@@ -374,7 +374,7 @@ Group:            Applications/File
 
 Requires:         %{name}-server = %{version}-%{release}
 Requires:         nfs-ganesha-gluster
-Requires:         pcs
+Requires:         pcs, /usr/bin/dbus-send
 
 %description ganesha
 GlusterFS is a distributed file-system capable of scaling to several
@@ -1268,6 +1268,9 @@ fi
 
 
 %changelog
+* Mon Dec 28 2015 Niels de Vos <ndevos@redhat.com>
+- hook scripts in glusterfs-ganesha use dbus-send, add dependency (#1294446)
+
 * Tue Sep 15 2015 Anand Nekkunti <anekkunt@redhat.com>
 - adding glusterfs-firewalld service (#1057295)