#! /bin/bash
# SPDX-License-Identifier: GPL-2.0
# Copyright (c) 2000-2003 Silicon Graphics, Inc.  All Rights Reserved.
#
# FS QA Test No. 016
#
# test end of log overwrite bug #796141
#
#
# pv 796141
#
# create a new FS, mostly fill the log. Then wrap the log back to the
# start bit by bit to force wiping of stale blocks near the end of the
# log. Check the block after the log ends to check for corruption
#
# assumptions :
#    - given we're only touching a single inode, the block after the
#      log which is in the middle ag should never be touched.
#      if it changes, we assume the log is writing over it
#

seq=`basename $0`
seqres=$RESULT_DIR/$seq
echo "QA output created by $seq"

here=`pwd`
tmp=/tmp/$$
status=1

trap "_cleanup; exit \$status" 0 1 2 3 15

_cleanup()
{
    cd /
    rm -f $tmp.*
    echo "*** unmount"
    _scratch_unmount 2>/dev/null
}

_block_filter()
{
    sed -e 's/[0-9][0-9]*\.\.[0-9][0-9]*/BLOCKRANGE/g'
}

_init()
{
    echo "*** determine log size"
    local sz_mb=50
    local dsize="-d size=${sz_mb}m"
    local lsize="-l size=$(_scratch_find_xfs_min_logblocks $dsize)b"
    local force_opts="$dsize $lsize"
    _scratch_mkfs_xfs $force_opts >> $seqres.full 2>&1

    # set log_size and log_size_bb globally
    log_size_bb=`_log_size`
    log_size=$((log_size_bb * 512))
    echo "log_size_bb = $log_size_bb log_size = $log_size" >> $seqres.full

    echo "*** reset partition"
    $here/src/devzero -b 2048 -n $sz_mb -v 198 $SCRATCH_DEV # write 0xc6
    echo "*** mkfs"
    #
    # Do not discard blocks as we check for patterns in free space.
    # 
    # First, make sure that mkfs supports '-K' option by using its
    # dry run (-N option) and then add it to the force_opts.
    #
    if _scratch_mkfs_xfs -N -K $force_opts >/dev/null 2>&1; then
        force_opts="-K $force_opts"
    fi
    echo mkfs_xfs $force_opts $SCRATCH_DEV >>$seqres.full
    _scratch_mkfs_xfs $force_opts >$tmp.mkfs0 2>&1
    [ $? -ne 0 ] && \
        _notrun "Cannot mkfs for this test using MKFS_OPTIONS specified"
    _filter_mkfs <$tmp.mkfs0 >/dev/null 2>$tmp.mkfs
    . $tmp.mkfs
    [ $logsunit -ne 0 ] && \
        _notrun "Cannot run this test using log MKFS_OPTIONS specified"

    # quotas generate extra log traffic so force it off
    _qmount_option noquota
}

_log_traffic()
{
    count=$1
    echo "*** generate log traffic"

    out=$SCRATCH_MNT/$$.tmp

    echo "   *** mount"
    if ! _try_scratch_mount
    then
        echo "failed to mount $SCRATCH_DEV"
        exit 1
    fi

    # having any quota enabled (acct/enfd) means extra log traffic - evil!
    $here/src/feature -U $SCRATCH_DEV && \
		_notrun "UQuota are enabled, test needs controlled log traffic"
    $here/src/feature -G $SCRATCH_DEV && \
		_notrun "GQuota are enabled, test needs controlled log traffic"
    $here/src/feature -P $SCRATCH_DEV && \
		_notrun "PQuota are enabled, test needs controlled log traffic"

    echo "   *** fiddle"
    while [ $count -ge 0 ]
    do
	touch $out
	sync
	rm $out
	sync
	let "count = count - 1"
    done

    echo "   *** unmount"
    if ! _scratch_unmount
    then
        echo "failed to unmount $SCRATCH_DEV"
        exit 1
    fi
}

_log_size()
{
    _scratch_xfs_logprint -tb | $AWK_PROG '
        /log file: / || /log device: / { print $7}
    '
}

_log_head()
{
    _scratch_xfs_logprint -tb | $AWK_PROG '
        /head:/ { print $5 }
    '
}

# Get log stripe unit for v2 logs; if none specified,
# (or v1 log) just return "1" block

_log_sunit()
{
    if [ ${lsunit:-0} -eq 0 ]; then
        echo $dbsize
    else
        expr $lsunit \* $dbsize
    fi
}

_after_log()
{
    _scratch_xfs_db -r -c "sb" -c "print" | $AWK_PROG '
        /logstart/  { logstart = $3 }
        /logblocks/ { logblocks = $3 }
        END {
            print logstart + logblocks
        }
    '
}

_check_corrupt()
{
    f="c6c6c6c6"
    echo "*** check for corruption"
    echo "expect $f..." >>$seqres.full
    _scratch_xfs_db -r -c "fsblock $2" -c "print" | head | tee -a $seqres.full | \
        grep -q -v "$f $f $f $f $f $f $f $f" && \
            _fail "!!! block $2 corrupted!"
}

# get standard environment, filters and checks
. ./common/rc
. ./common/filter
. ./common/quota

# real QA test starts here
_supported_fs xfs

rm -f $seqres.full

_require_scratch
_init

block=`_after_log $SCRATCH_DEV`
echo "fsblock after log = $block"               >>$seqres.full
_check_corrupt $SCRATCH_DEV $block

actual_log_size=`_log_size`
echo "log size = $actual_log_size BB"                      >>$seqres.full
head=`_log_head`
echo "log position = $head"                     >>$seqres.full
lsunit=`_log_sunit`
echo "log sunit = $lsunit"			>>$seqres.full

# sanity checks
[ $actual_log_size -eq $log_size_bb ] || \
    _fail "!!! unexpected log size $size"
[ $head -eq 2 -o $head -eq $((lsunit/512)) ] || \
    _fail "!!! unexpected initial log position $head vs. $((lsunit/512))"

# Step 1: Run 200 ops to estimate how how many log blocks are used for each op.
# Ignore the fact that it will also include an unmount record; this should be
# small overall.
echo "    lots of traffic for sampling" >>$seqres.full
sample_size_ops=200
_log_traffic $sample_size_ops
head1=`_log_head`
num_blocks=`expr $head1 - $head`
blocks_per_op=`echo "scale=3; $num_blocks / $sample_size_ops" | bc`
echo "log position = $head1; old log position: $head" >> $seqres.full
echo "blocks_per_op = $blocks_per_op" >>$seqres.full

# Step 2: Quickly advance the log from wherever step 1 left us to the point
# where the log is now 80% full on its first cycle.

# Estimate the number of ops needed to get the log head close to but not past
# near_end_min for a single mount.  We'd rather fall short and have to step our
# way closer to the end than run past the end, so our target for this second
# step is to fill 80% of the first cycle of the log.
num_expected_ops=$(( 8 * $(echo "$log_size_bb / $blocks_per_op" | bc) / 10))
echo "num_expected_ops = $num_expected_ops" >>$seqres.full

# Compute the number of ops needed to get from wherever we are right now in
# the log cycle to the 80% point.
num_expected_to_go=`echo "$num_expected_ops - $sample_size_ops" | bc`
echo "num_expected_to_go = $num_expected_to_go" >>$seqres.full

echo "    lots more traffic" >>$seqres.full
_log_traffic $num_expected_to_go
head=`_log_head`
echo "log position = $head"                     >>$seqres.full

# Step 3: Gradually advance log traffic to get us from wherever step 2 left us
# to the point where the log is within approximately 20 ops of wrapping into
# the second cycle.

# Since this is a log wrapping test, it's critical to push the log head to the
# point where it will wrap around within twenty rounds of ops.  Compute the
# expected value of the log head when we get to this point.  This "/ 1" piece
# tricks bc into printing integer numbers.
near_end_min=$(echo "$log_size_bb - (20 * $blocks_per_op / 1)" | bc)
echo "near_end_min = $near_end_min" >>$seqres.full

# Step us (in batches of 10 ops) to our goal.
while [ $head -lt $near_end_min ]; do
	echo "    bump traffic from $head towards $near_end_min" >> $seqres.full
	_log_traffic 10 > /dev/null 2>&1
	head=$(_log_head)
done

[ $head -gt $near_end_min -a $head -lt $log_size_bb ] || \
    _fail "!!! unexpected near end log position $head"

# Step 4: Try to wrap the log, checking for corruption with each advance.
# This is the functionality that we're actually trying to test.  We will try
# 40 ops (in batches of 2) to try to wrap the log.
for c in `seq 0 20`
do
    echo "   little traffic"            >>$seqres.full
    _log_traffic 2
    head=`_log_head`
    echo "log position = $head"         >>$seqres.full
    _check_corrupt $SCRATCH_DEV $block
done

[ $head -lt 1000 ] || \
    _fail "!!! unexpected wrapped log position $head"

# success, all done
status=0
exit