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>

2 files changed, 67 insertions, 10 deletions

diff --git a/tests/basic/tier/fops-during-migration.t b/tests/basic/tier/fops-during-migration.t
index b80511a400d..96180d23917 100755
--- a/tests/basic/tier/fops-during-migration.t
+++ b/tests/basic/tier/fops-during-migration.t
@@ -61,9 +61,11 @@ create_dist_tier_vol $NUM_BRICKS
 # Mount FUSE
 TEST glusterfs -s $H0 --volfile-id $V0 $M0
 
+$CLI volume set $V0 diagnostics.client-log-level DEBUG
+
 TEST mkdir $M0/dir1
 
-# Create a large file (200MB), so that rebalance takes time
+# Create a large file (320MB), so that rebalance takes time
 # The file will be created on the hot tier
 
 dd if=/dev/zero of=$M0/dir1/FILE1 bs=64k count=5120
@@ -83,14 +85,9 @@ echo "File path on cold tier: "$CPATH
 # Test setxattr
 TEST setfattr -n "user.test_xattr" -v "qwerty" $M0/dir1/FILE1
 
-# Test hard link creation
-TEST ln $M0/dir1/FILE1 $M0/dir1/lnk1
-TEST ln $M0/dir1/FILE1 $M0/lnk2
-
 # Change the file contents while it is being migrated
 echo $TEST_STR > $M0/dir1/FILE1
 
-
 # The file contents should have changed even if the file
 # is not done migrating
 EXPECT "1" check_file_content $M0/dir1/FILE1 "$TEST_STR"
@@ -103,10 +100,6 @@ EXPECT_WITHIN $REBALANCE_TIMEOUT "no" is_sticky_set $CPATH
 EXPECT "1" check_file_content $M0/dir1/FILE1 "$TEST_STR"
 
 
-linkcountsrc=$(stat -c %h $M0/dir1/FILE1)
-echo $linkcountsrc
-TEST [[ $linkcountsrc == 3 ]]
-
 TEST getfattr -n "user.test_xattr" $M0/dir1/FILE1
 
 cleanup;
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;
+