cluster/tier: readdirp to cold tier only

It is possible a file would get migrated in the middle
of a readdir operation. If there are four subvolumes A,B,C,D,
and if readdir reads them in order and reaches subvol B,
then, if a file is moved from D to A, it will not be included
in the readdir output.

This phenonema has pre-existed in DHT migration but is more
apparent in tiering.

When a file is moved off the hashed subvolume a T file is created.
For tiering, we will make the cold subvolume the hashed subvolume.
This will ensure the creation of a T file. Readdir will not skip T
files in the tier translator.

Making the cold subvolume the hashed subvolume ensures the T
files created on promotions or creates will be less likely to
fill the volume.

Creates still put the data on the hot subvolume.

Change-Id: Ifde557d3d0e94a4570ca9f115adee3db2ee75407
BUG:  1281598
Signed-off-by: Dan Lambright <dlambrig@redhat.com>
Reviewed-on: http://review.gluster.org/12530
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Tested-by: NetBSD Build System <jenkins@build.gluster.org>
Reviewed-by: N Balachandran <nbalacha@redhat.com>
Reviewed-by: Raghavendra G <rgowdapp@redhat.com>

1 files changed, 64 insertions, 0 deletions

diff --git a/tests/basic/tier/readdir-during-migration.t b/tests/basic/tier/readdir-during-migration.t
new file mode 100644
index 00000000000..42199c57768
--- /dev/null
+++ b/tests/basic/tier/readdir-during-migration.t
@@ -0,0 +1,64 @@
+#!/bin/bash
+
+. $(dirname $0)/../../include.rc
+. $(dirname $0)/../../volume.rc
+. $(dirname $0)/../../tier.rc
+
+
+NUM_BRICKS=3
+DEMOTE_FREQ=5
+PROMOTE_FREQ=5
+NUM_FILES=30
+TEST_DIR=test
+# 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 start $V0
+        TEST $CLI volume attach-tier $V0 $H0:$B0/hot/${V0}{0..$1}
+        TEST $CLI volume set $V0 cluster.tier-mode test
+        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
+}
+
+function check_file_count() {
+    if [ $(ls -1 | wc -l) == $1 ]; then
+        echo "1"
+    else
+        echo "0"
+    fi
+}
+
+cleanup;
+
+
+TEST glusterd
+
+#Create and start a tiered volume
+create_dist_tier_vol $NUM_BRICKS
+
+# Mount FUSE
+TEST glusterfs -s $H0 --volfile-id $V0 $M0
+
+# Create a number of "legacy" files before attaching tier
+mkdir $M0/${TEST_DIR}
+cd $M0/${TEST_DIR}
+TEST create_many_files tfile $NUM_FILES
+
+EXPECT "1" check_file_count $NUM_FILES
+
+sleep $DEMOTE_FREQ
+
+EXPECT "1" check_file_count $NUM_FILES
+
+cd /
+
+cleanup;
+