cluster/tier: add pause tier for snapshots

This is a backport of 12304

Snaps of tiered volumes cannot handle files undergoing migration.
We implement a helper mechanism to "pause" migration. Any files
undergoing migration are aborted. Clean up is done to remove
sticky bits and data at the destination. Migration is restarted
after snap completes.

For testing an internal switch is added. It is not exposed externally.

gluster volume set vol1 tier-pause [true|false]

> Change-Id: Ia85bbf89ac142e9b7e73fcbef98bb9da86097799
> BUG: 1267950
> Signed-off-by: Dan Lambright <dlambrig@redhat.com>
> Reviewed-on: http://review.gluster.org/12304
> Reviewed-by: N Balachandran <nbalacha@redhat.com>
> Tested-by: NetBSD Build System <jenkins@build.gluster.org>
> Tested-by: Gluster Build System <jenkins@build.gluster.com>
Signed-off-by: Dan Lambright <dlambrig@redhat.com>

Conflicts:
	xlators/mgmt/glusterd/src/glusterd-messages.h

Change-Id: I5f039d8d38a4c915bd873969f336b96755a0b8f1
BUG: 1274101
Reviewed-on: http://review.gluster.org/12411
Tested-by: NetBSD Build System <jenkins@build.gluster.org>
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Dan Lambright <dlambrig@redhat.com>
Tested-by: Dan Lambright <dlambrig@redhat.com>

1 files changed, 87 insertions, 0 deletions

diff --git a/tests/basic/tier/fops-during-migration-pause.t b/tests/basic/tier/fops-during-migration-pause.t
new file mode 100755
index 00000000000..702465f4191
--- /dev/null
+++ b/tests/basic/tier/fops-during-migration-pause.t
@@ -0,0 +1,87 @@
+#!/bin/bash
+
+. $(dirname $0)/../../include.rc
+. $(dirname $0)/../../volume.rc
+
+
+NUM_BRICKS=3
+DEMOTE_FREQ=5
+PROMOTE_FREQ=5
+
+TEST_STR="Testing write and truncate fops on tier migration"
+
+function is_sticky_set () {
+        echo $1
+        if [ -k $1 ];
+        then
+                echo "yes"
+        else
+                echo "no"
+        fi
+}
+
+
+# Creates a tiered volume with pure distribute hot and cold tiers
+# Both hot and cold tiers will have an equal number of bricks.
+
+function create_dist_tier_vol () {
+        mkdir $B0/cold
+        mkdir $B0/hot
+        TEST $CLI volume create $V0 $H0:$B0/cold/${V0}{0..$1}
+        TEST $CLI volume set $V0 performance.quick-read off
+        TEST $CLI volume set $V0 performance.io-cache off
+        TEST $CLI volume set $V0 features.ctr-enabled on
+        TEST $CLI volume start $V0
+        TEST $CLI volume attach-tier $V0 $H0:$B0/hot/${V0}{0..$1}
+        TEST $CLI volume set $V0 cluster.tier-demote-frequency $DEMOTE_FREQ
+        TEST $CLI volume set $V0 cluster.tier-promote-frequency $PROMOTE_FREQ
+        TEST $CLI volume set $V0 cluster.read-freq-threshold 0
+        TEST $CLI volume set $V0 cluster.write-freq-threshold 0
+}
+
+
+cleanup;
+
+#Basic checks
+TEST glusterd
+TEST pidof glusterd
+TEST $CLI volume info
+
+
+#Create and start a tiered volume
+create_dist_tier_vol $NUM_BRICKS
+
+# Mount FUSE
+TEST glusterfs -s $H0 --volfile-id $V0 $M0
+
+TEST mkdir $M0/dir1
+
+# Create a large file (200MB), so that rebalance takes time
+# The file will be created on the hot tier
+
+dd if=/dev/zero of=$M0/dir1/FILE1 bs=64k count=5120
+
+# Get the path of the file on the hot tier
+HPATH=`find $B0/hot/ -name  FILE1`
+echo "File path on hot tier: "$HPATH
+
+
+# Wait for the tier process to demote the file
+EXPECT_WITHIN $REBALANCE_TIMEOUT "yes" is_sticky_set $HPATH
+
+TEST $CLI volume set $V0 cluster.tier-pause on
+
+# Wait for the tier process to finish migrating the file
+EXPECT_WITHIN $REBALANCE_TIMEOUT "no" is_sticky_set $HPATH
+
+# Get the path of the file on the cold tier
+CPATH=`find $B0/cold/ -name  FILE1`
+
+# make sure destination is empty
+TEST ! test -s $CPATH
+
+# make sure source exists and not empty
+TEST test -s $HPATH
+
+cleanup;
+