afr: Don't write to sparse regions of sink.

Corresponding afr-v2 fix: http://review.gluster.org/#/c/9480/

Problem:
When data-self-heal-algorithm is set to 'full', shd just reads from
source and writes to sink. If source file happened to be sparse (VM
workloads), we end up actually writing 0s to the corresponding regions
of the sink causing it to lose its sparseness.

Fix:
If the source file is sparse, and the data read from source and sink are
both zeros for that range, skip writing that range to the sink.

Change-Id: Iade957e4173c87e45a2881df501ba2ad3eb1a172
BUG: 1190633
Signed-off-by: Ravishankar N <ravishankar@redhat.com>
Reviewed-on: http://review.gluster.org/9611
Reviewed-by: Pranith Kumar Karampuri <pkarampu@redhat.com>
Reviewed-by: Krutika Dhananjay <kdhananj@redhat.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Niels de Vos <ndevos@redhat.com>

2 files changed, 147 insertions, 0 deletions

diff --git a/tests/basic/afr/sparse-file-self-heal.t b/tests/basic/afr/sparse-file-self-heal.t
new file mode 100644
index 00000000000..f2a0863c686
--- /dev/null
+++ b/tests/basic/afr/sparse-file-self-heal.t
@@ -0,0 +1,138 @@
+#!/bin/bash
+
+#This file checks if self-heal of files with holes is working properly or not
+#bigger is 2M, big is 1M, small is anything less
+. $(dirname $0)/../../include.rc
+. $(dirname $0)/../../volume.rc
+
+cleanup;
+
+TEST glusterd
+TEST pidof glusterd
+TEST $CLI volume create $V0 replica 2 $H0:$B0/${V0}{0,1}
+TEST $CLI volume set $V0 data-self-heal-algorithm full
+TEST $CLI volume start $V0
+
+TEST glusterfs --volfile-id=/$V0 --volfile-server=$H0 $M0;
+TEST dd if=/dev/urandom of=$M0/small count=1 bs=1024k
+TEST dd if=/dev/urandom of=$M0/bigger2big count=1 bs=2048k
+TEST dd if=/dev/urandom of=$M0/big2bigger count=1 bs=1024k
+TEST truncate -s 1G $M0/FILE
+
+TEST kill_brick $V0 $H0 $B0/${V0}0
+
+#File with >128k size hole
+TEST truncate -s 1M $M0/big
+big_md5sum=$(md5sum $M0/big | awk '{print $1}')
+
+#File with <128k hole
+TEST truncate -s 0 $M0/small
+TEST truncate -s 64k $M0/small
+small_md5sum=$(md5sum $M0/small | awk '{print $1}')
+
+#Bigger file truncated to big size hole.
+TEST truncate -s 0 $M0/bigger2big
+TEST truncate -s 1M $M0/bigger2big
+bigger2big_md5sum=$(md5sum $M0/bigger2big | awk '{print $1}')
+
+#Big file truncated to Bigger size hole
+TEST truncate -s 2M $M0/big2bigger
+big2bigger_md5sum=$(md5sum $M0/big2bigger | awk '{print $1}')
+
+#Write data to file and restore its sparseness
+TEST dd if=/dev/urandom of=$M0/FILE count=1 bs=131072
+TEST truncate -s 1G $M0/FILE
+
+$CLI volume start $V0 force
+EXPECT_WITHIN $CHILD_UP_TIMEOUT "1" afr_child_up_status $V0 0
+EXPECT_WITHIN $PROCESS_UP_TIMEOUT "Y" glustershd_up_status
+EXPECT_WITHIN $CHILD_UP_TIMEOUT "1" afr_child_up_status_in_shd $V0 0
+EXPECT_WITHIN $CHILD_UP_TIMEOUT "1" afr_child_up_status_in_shd $V0 1
+TEST gluster volume heal $V0 full
+EXPECT_WITHIN $HEAL_TIMEOUT "0" afr_get_pending_heal_count $V0
+
+big_md5sum_0=$(md5sum $B0/${V0}0/big | awk '{print $1}')
+small_md5sum_0=$(md5sum $B0/${V0}0/small | awk '{print $1}')
+bigger2big_md5sum_0=$(md5sum $B0/${V0}0/bigger2big | awk '{print $1}')
+big2bigger_md5sum_0=$(md5sum $B0/${V0}0/big2bigger | awk '{print $1}')
+
+EXPECT $big_md5sum echo $big_md5sum_0
+EXPECT $small_md5sum echo $small_md5sum_0
+EXPECT $big2bigger_md5sum echo $big2bigger_md5sum_0
+EXPECT $bigger2big_md5sum echo $bigger2big_md5sum_0
+
+
+EXPECT "1" has_holes $B0/${V0}0/big
+#Because self-heal writes the final chunk hole should not be there for
+#files < 128K
+EXPECT "0" has_holes $B0/${V0}0/small
+# Since source is smaller than sink, self-heal does blind copy so no holes will
+# be present
+EXPECT "0" has_holes $B0/${V0}0/bigger2big
+EXPECT "1" has_holes $B0/${V0}0/big2bigger
+
+#Check that self-heal has not written 0s to sink and made it non-sparse.
+USED_KB=`du -s $B0/${V0}0/FILE|cut -f1`
+TEST [ $USED_KB -lt 1000000 ]
+TEST rm -f $M0/*
+
+#check the same tests with diff self-heal
+TEST $CLI volume set $V0 data-self-heal-algorithm diff
+
+TEST dd if=/dev/urandom of=$M0/small count=1 bs=1024k
+TEST dd if=/dev/urandom of=$M0/big2bigger count=1 bs=1024k
+TEST dd if=/dev/urandom of=$M0/bigger2big count=1 bs=2048k
+TEST truncate -s 1G $M0/FILE
+
+TEST kill_brick $V0 $H0 $B0/${V0}0
+
+#File with >128k size hole
+TEST truncate -s 1M $M0/big
+big_md5sum=$(md5sum $M0/big | awk '{print $1}')
+
+#File with <128k hole
+TEST truncate -s 0 $M0/small
+TEST truncate -s 64k $M0/small
+small_md5sum=$(md5sum $M0/small | awk '{print $1}')
+
+#Bigger file truncated to big size hole
+TEST truncate -s 0 $M0/bigger2big
+TEST truncate -s 1M $M0/bigger2big
+bigger2big_md5sum=$(md5sum $M0/bigger2big | awk '{print $1}')
+
+#Big file truncated to Bigger size hole
+TEST truncate -s 2M $M0/big2bigger
+big2bigger_md5sum=$(md5sum $M0/big2bigger | awk '{print $1}')
+
+#Write data to file and restore its sparseness
+TEST dd if=/dev/urandom of=$M0/FILE count=1 bs=131072
+TEST truncate -s 1G $M0/FILE
+
+$CLI volume start $V0 force
+EXPECT_WITHIN $CHILD_UP_TIMEOUT "1" afr_child_up_status $V0 0
+EXPECT_WITHIN $PROCESS_UP_TIMEOUT "Y" glustershd_up_status
+EXPECT_WITHIN $CHILD_UP_TIMEOUT "1" afr_child_up_status_in_shd $V0 0
+EXPECT_WITHIN $CHILD_UP_TIMEOUT "1" afr_child_up_status_in_shd $V0 1
+TEST gluster volume heal $V0 full
+EXPECT_WITHIN $HEAL_TIMEOUT "0" afr_get_pending_heal_count $V0
+
+big_md5sum_0=$(md5sum $B0/${V0}0/big | awk '{print $1}')
+small_md5sum_0=$(md5sum $B0/${V0}0/small | awk '{print $1}')
+bigger2big_md5sum_0=$(md5sum $B0/${V0}0/bigger2big | awk '{print $1}')
+big2bigger_md5sum_0=$(md5sum $B0/${V0}0/big2bigger | awk '{print $1}')
+
+EXPECT $big_md5sum echo $big_md5sum_0
+EXPECT $small_md5sum echo $small_md5sum_0
+EXPECT $big2bigger_md5sum echo $big2bigger_md5sum_0
+EXPECT $bigger2big_md5sum echo $bigger2big_md5sum_0
+
+EXPECT "1" has_holes $B0/${V0}0/big
+EXPECT "1" has_holes $B0/${V0}0/big2bigger
+EXPECT "0" has_holes $B0/${V0}0/bigger2big
+EXPECT "0" has_holes $B0/${V0}0/small
+
+#Check that self-heal has not written 0s to sink and made it non-sparse.
+USED_KB=`du -s $B0/${V0}0/FILE|cut -f1`
+TEST [ $USED_KB -lt 1000000 ]
+
+cleanup
diff --git a/tests/volume.rc b/tests/volume.rc
index 1c58597c661..53f863e2733 100644
--- a/tests/volume.rc
+++ b/tests/volume.rc
@@ -293,3 +293,12 @@ function get_hex_xattr {
         local path=$2
         getfattr -d -m. -e hex $2 2>/dev/null | grep $1 | cut -f2 -d'=' | cut -f2 -d'x'
 }
+
+function has_holes {
+        if [ $((`stat -c '%b*%B-%s' $1`)) -lt 0 ];
+        then
+                echo "1"
+        else
+                echo "0"
+        fi
+}