cluster/distribute: Ignore non-participating subvols for layout checks

Backporting fix http://review.gluster.org/#/c/4668/

When subvols-per-directory is < available subvols, then there are layouts
which are not populated. This leads to incorrect identification of holes or
overlaps. We need to ignore layouts, which have err == 0, and start == stop.
In the current scenario (start == stop == 0).

Additionally, in layout-merge, treat missing xattrs as err = 0. In case of
missing layouts, anomalies will reset them.

For any other valid subvoles, err != 0 in case of layouts being zeroed out.

Also reverted back dht_selfheal_dir_xattr, which does layout calculation only
on subvols which have errors.

BUG: 921408
Change-Id: I75a8edcb92af5b53b3253c9addd7a812e9242836
Signed-off-by: shishir gowda <sgowda@redhat.com>
Reviewed-on: http://review.gluster.org/4800
Reviewed-by: Amar Tumballi <amarts@redhat.com>
Reviewed-by: Jeff Darcy <jdarcy@redhat.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>

2 files changed, 90 insertions, 7 deletions

diff --git a/tests/bugs/bug-921408.t b/tests/bugs/bug-921408.t
new file mode 100755
index 00000000000..ef2b4fb21cd
--- /dev/null
+++ b/tests/bugs/bug-921408.t
@@ -0,0 +1,89 @@
+#!/bin/bash
+
+. $(dirname $0)/../include.rc
+. $(dirname $0)/../fileio.rc
+. $(dirname $0)/../dht.rc
+
+cleanup;
+wait_check_status ()
+{
+        n=0
+        while [ $n -lt $1 ]
+        do
+                ret=$(rebalance_completed)
+                if [ $ret == "0" ]
+                then
+                        return 0;
+                else
+                        sleep 1
+                        n=`expr $n + 1`;
+                fi
+       done
+       return 1;
+}
+
+addbr_rebal_till_layout_change()
+{
+        val=1
+        l=$1
+        i=1
+        while [ $i -lt 5 ]
+        do
+                $CLI volume add-brick $V0 $H0:$B0/${V0}$l &>/dev/null
+                $CLI volume rebalance $V0 fix-layout start &>/dev/null
+                wait_check_status 15
+                if [ $? -eq 1 ]
+                then
+                        break
+                fi
+                NEW_LAYOUT=`get_layout $B0/${V0}0`
+                if [ $OLD_LAYOUT == $NEW_LAYOUT ]
+                then
+                        i=`expr $i + 1`;
+                        l=`expr $l + 1`;
+                else
+                        val=0
+                        break
+                fi
+        done
+        return $val
+}
+TEST glusterd
+TEST pidof glusterd
+
+TEST $CLI volume create $V0 $H0:$B0/${V0}0
+TEST $CLI volume set $V0 subvols-per-directory 1
+TEST $CLI volume start $V0
+
+TEST glusterfs -s $H0 --volfile-id $V0 $M0;
+
+TEST mkdir $M0/test
+TEST touch $M0/test/test
+
+fd=`fd_available`
+TEST fd_open $fd "rw" $M0/test/test
+
+OLD_LAYOUT=`get_layout $B0/${V0}0`
+
+addbr_rebal_till_layout_change 1
+
+TEST [ $? -eq 0 ]
+
+for i in $(seq 1 1000)
+do
+	ls -l $M0/ >/dev/null
+	ret=$?
+	if [ $ret != 0 ]
+	then
+		break
+	fi
+done
+
+TEST [ $ret == 0 ];
+TEST fd_close $fd;
+
+TEST umount $M0
+TEST $CLI volume stop $V0
+TEST $CLI volume delete $V0
+
+cleanup
diff --git a/tests/dht.rc b/tests/dht.rc
index ee92a47bd62..663ea543173 100644
--- a/tests/dht.rc
+++ b/tests/dht.rc
@@ -2,13 +2,7 @@
 
 function get_layout()
 {
-        layout=`getfattr -n trusted.glusterfs.dht -e hex $1 2>&1|grep dht |cut -d = -f2`
-        if [ $? -eq 1]
-        then
-                return -1
-        else
-                return $layout
-        fi
+        getfattr -n trusted.glusterfs.dht -e hex $1 2>&1|grep dht |cut -d = -f2
 
 }