Test script to create file with specific data-stripe layout and pre-computed
parity values.
Inject corruption into data-stripe and verify scrubbing process fixes corrupted
block.
It also attempts to validate the corresponding parity block value.
Signed-off-by: Lakshmipathi.G <lakshmipath...@giis.co.in>
---
.../020-raid5-datastripe-corruption/test.sh | 275 +++++++++++++++++++++
1 file changed, 275 insertions(+)
create mode 100755 tests/misc-tests/020-raid5-datastripe-corruption/test.sh
diff --git a/tests/misc-tests/020-raid5-datastripe-corruption/test.sh
b/tests/misc-tests/020-raid5-datastripe-corruption/test.sh
new file mode 100755
index 0000000..3c743eb
--- /dev/null
+++ b/tests/misc-tests/020-raid5-datastripe-corruption/test.sh
@@ -0,0 +1,275 @@
+#!/bin/bash
+#
+# Raid5: Inject data stripe corruption and fix them using scrub.
+#
+# Script will perform the following:
+# 1) Create Raid5 using 3 loopback devices.
+# 2) Ensure file layout is created in a predictable manner.
+# Each data stripe(64KB) should uniquely start with 'DNxxxx',
+# where N represents the data stripe number.(ex:D0xxxx,D1xxxx etc)
+# 3) Once file is created with specific layout, gather data stripe details
+# like devicename, position and actual on-disk data.
+# 4) Now use 'dd' to verify the data-stripe against its expected value.
+# 5) At this stage, gather possible parity location for this specific data
+# stripe. The parity values is pre-computed for known data-stripes.
+# 6) Inject corruption into given data-stripe by zero'ing out its first 4
bytes.
+# 7) After injecting corruption, running online-scrub is expected to fix
+# the corrupted data stripe with the help of parity block and
+# corresponding data stripe.
+# 8) If scrub successful, verify the data stripe has original un-corrupted
value.
+# 9) If scrub successful, re-generate list of possible parity blocks, this
+# list must match one prepared in step 5. Otherwise report it as possible
parity
+# bug issue.
+# 10) If no issues found, cleanup files and devices. Repeat the process for
+# different file size and data-stripe.
+#
+# Note: This script doesn't handle parity block corruption.
+
+source $TOP/tests/common
+
+check_prereq btrfs
+check_prereq mkfs.btrfs
+
+setup_root_helper
+prepare_test_dev 512M
+
+ndevs=3
+declare -a devs
+device_name=""
+stripe_offset=""
+stripe_content=""
+known_parity_value="00010000000000000000000000000000"
+
+LAYOUT_TMP=$(mktemp --tmpdir btrfs-progs-raid5-file.layoutXXXXXX)
+STRIPEINFO_TMP=$(mktemp --tmpdir btrfs-progs-raid5-file.infoXXXXXX)
+PARITYINFO1_TMP=$(mktemp --tmpdir btrfs-progs-raid5-initial.parityXXXXXX)
+PARITYINFO2_TMP=$(mktemp --tmpdir btrfs-progs-raid5-end.parityXXXXXX)
+
+prepare_devices()
+{
+ for i in `seq $ndevs`; do
+ touch img$i
+ chmod a+rw img$i
+ truncate -s0 img$i
+ truncate -s512M img$i
+ devs[$i]=`run_check_stdout $SUDO_HELPER losetup --find --show
img$i`
+ done
+}
+
+cleanup_devices()
+{
+ for dev in ${devs[@]}; do
+ run_check $SUDO_HELPER losetup -d $dev
+ done
+ for i in `seq $ndevs`; do
+ truncate -s0 img$i
+ done
+ run_check $SUDO_HELPER losetup --all
+}
+
+test_do_mkfs()
+{
+ run_check $SUDO_HELPER $TOP/mkfs.btrfs -f \
+ $@
+}
+
+test_mkfs_multi()
+{
+ test_do_mkfs $@ ${devs[@]}
+}
+
+#$1 Filename
+#$2 Expected no.of data stripes for the file.
+create_layout(){
+ fname=$1
+ size=$(( $2 * 65536 ))
+ n=0
+ bs_value=1
+ stripe=0
+ while (( $n < $size ))
+ do
+ if [ $(( $n % 65536 )) -eq 0 ]; then
+ val='D'$stripe
+ echo -n $val
+ stripe=$(( $stripe+1 ))
+ # ensure proper value
+ bs_value=`echo "${#val}"`
+ else
+ echo -n 'x'
+ bs_value=1
+ fi
+ n=$(( $n+$bs_value ))
+ done | dd of="$TEST_MNT"/$fname bs=$bs_value conv=notrunc &> /dev/null
+}
+
+find_data_stripe_details(){
+ for dev in ${devs[@]}; do
+ echo $dev >> $LAYOUT_TMP
+ $SUDO_HELPER cat $dev | hexdump -e '"%010_ad|" 16/1 "%_p"
"|\n"' |
+ grep -P 'D[0-9]+xx' >> $LAYOUT_TMP
+ done
+}
+#$1 - file to save possible parity locations
+find_parity_stripe_count(){
+ PARITY_COUNT=$1
+ for dev in ${devs[@]}; do
+ echo "Possible parity stripes locations on device: $dev" >>
$PARITY_COUNT
+ $SUDO_HELPER cat $dev | hexdump -e '"%010_ad|" 16/1 "%02X"
"\n"' |
+ grep $known_parity_value >> $PARITY_COUNT
+ done
+}
+
+#Collect data stripe information in a readable manner.
+save_data_stripe_details(){
+ devname=""
+ for entry in `cat $LAYOUT_TMP`; do
+ echo $entry | grep -q '^\/dev\/loop' > /dev/null
+
+ if [ $? -eq 0 ]; then
+ devname=$entry
+ else
+ echo $devname"|"$entry >> $STRIPEINFO_TMP
+ fi
+ done
+ #sorting is not mandatory
+ sort -t'|' -n -k3 $STRIPEINFO_TMP -o $STRIPEINFO_TMP
+}
+#Setup current known parity value
+#$1 - integer to identify data-stripe range
+set_parity_value(){
+ num_digits=$1
+ case $num_digits in
+ 1) #parity for D0xxxx to D9xxxx
+ known_parity_value="00010000000000000000000000000000"
+ ;;
+ 2) #parity for D10xxx to D99xxx
+ known_parity_value="00000100000000000000000000000000"
+ ;;
+ esac
+}
+
+
+#Corrupt given data stripe
+corrupt_data_stripe(){
+
+ data_stripe_num=$1
+ data_stripe_entry="D"${data_stripe_num}"xxxx"
+ stripe_entry=`grep "${data_stripe_entry}" $STRIPEINFO_TMP`
+
+ #Each entry will have format like "device|position|16-byte content"
+ #Example: /dev/loop1|0063176704|D0xxxxxxxxxxxxxx|
+ device_name=$(echo $stripe_entry | awk -F"|" '{print $1}')
+ stripe_offset=$(echo $stripe_entry | awk -F"|" '{print $2}')
+ #Remove leading zeros
+ stripe_offset=$(echo $stripe_offset | sed 's/^0*//')
+ stripe_content=$(echo $stripe_entry | awk -F"|" '{print $3}')
+
+ echo "Corrupting $device_name at position $stripe_offset \
+ which has $stripe_content" >> "$RESULTS"
+
+ #verify the value at this position
+ original_value=$($SUDO_HELPER dd 2>/dev/null if=$device_name bs=1 \
+ count=16 skip=$stripe_offset)
+
+ if [ $original_value != $stripe_content ];then
+ echo "$original_value != $stripe_content"
+ _fail "Data stripe mismatch. Possible use of incorrect block."
+ else
+ echo "Found on-disk value: $original_value " >> "$RESULTS"
+ fi
+ num_digits=$(echo $original_value | grep -o "[0-9]" | grep -c "")
+ set_parity_value $num_digits
+ find_parity_stripe_count $PARITYINFO1_TMP
+
+ #Corrupt the given data stripe
+ $SUDO_HELPER dd if=/dev/zero of=$device_name bs=1 count=4 \
+ seek=$stripe_offset conv=notrunc &> /dev/null
+
+ #Fetch value again.
+ corrupted_value=$($SUDO_HELPER dd 2>/dev/null if=$device_name \
+ bs=1 count=16 skip=$stripe_offset)
+
+ if [ $corrupted_value == $original_value ];then
+ echo "original:$original_value corrupted:$corrupted_value"
+ _fail "Corruption failed. Possible use of incorrect block."
+ else
+ echo "Corruption completed at $stripe_offset" >> "$RESULTS"
+ fi
+}
+
+#Verify data stripe after scrub
+verify_data_stripe(){
+
+ value_after_scrub=$($SUDO_HELPER dd 2>/dev/null if=$device_name bs=1 \
+ count=16 skip=$stripe_offset)
+ if [ $value_after_scrub != $stripe_content ];then
+ echo "Found on-disk value: $value_after_scrub" >> "$RESULTS"
+ _fail "Scrub failed to fix data stripe corruption."
+ else
+ echo "Scrub corrected value: $value_after_scrub" >> "$RESULTS"
+ fi
+}
+
+#Verify parity stripe count after scrub
+verify_parity_stripe(){
+ find_parity_stripe_count $PARITYINFO2_TMP
+ parity_stripe_count_before=$(md5sum $PARITYINFO1_TMP | cut -f1 -d' ')
+ parity_stripe_count_after=$(md5sum $PARITYINFO2_TMP | cut -f1 -d' ')
+ if [ "$parity_stripe_count_before" != "$parity_stripe_count_after"
];then
+ echo "Mismatch between $PARITYINFO1_TMP $PARITYINFO2_TMP,
please check."
+ diff $PARITYINFO1_TMP $PARITYINFO2_TMP
+ _fail "Scrub corrupted parity stripe."
+ else
+ echo "Parity stripe check passed." >> "$RESULTS"
+ fi
+}
+
+
+#$1 Filename
+#$2 File with 'n' no.of data stripes
+#$3 Data stripe to corrupt
+test_raid5_datastripe_corruption(){
+ filename=$1
+ stripe_num=$2
+ test_stripe=$3
+
+ prepare_devices
+ dev1=${devs[1]}
+ dev2=${devs[2]}
+ dev3=${devs[3]}
+
+ test_mkfs_multi -d raid5 -m raid5
+ run_check $SUDO_HELPER mount $dev1 $TEST_MNT
+ create_layout $filename $stripe_num
+ run_check $SUDO_HELPER umount "$TEST_MNT"
+
+ #Gather data stripe informations like specific device,offset
+ find_data_stripe_details
+ save_data_stripe_details
+ corrupt_data_stripe $test_stripe
+
+ #Mount the device and start scrub
+ run_check $SUDO_HELPER mount $dev1 $TEST_MNT
+ run_check $SUDO_HELPER btrfs scrub start $TEST_MNT
+ #Introduce delay, hopefully scrubbing will be finished.
+ sleep 10
+
+ #Validate
+ verify_data_stripe
+ verify_parity_stripe
+
+ #cleanup
+ run_check $SUDO_HELPER umount "$TEST_MNT"
+ cleanup_devices
+ rm -f $LAYOUT_TMP
+ rm -f $STRIPEINFO_TMP
+}
+
+
+test_raid5_datastripe_corruption file128k.txt 2 1 #file with 2 stripe,corrupt
1st.
+test_raid5_datastripe_corruption file192k.txt 3 2 #file with 3 stripe,corrupt
2nd.
+test_raid5_datastripe_corruption file256k.txt 4 3
+test_raid5_datastripe_corruption file512k.txt 8 6
+test_raid5_datastripe_corruption file768k.txt 12 10
+test_raid5_datastripe_corruption file1m.txt 16 14 #1MB file, corrupt 14th
stripe.
+test_raid5_datastripe_corruption file2m.txt 32 23 #2MB file, corrupt 23rd
stripe
--
2.7.4
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