#! /bin/bash
# SPDX-License-Identifier: GPL-2.0-or-later
# Copyright (c) 2021 Oracle.  All Rights Reserved.
#
# FS QA Test No. 146
#
# This is a regression test for commit 2a6ca4baed62 ("xfs: make sure the rt
# allocator doesn't run off the end") which fixes an overflow error in the
# _near realtime allocator.  If the rt bitmap ends exactly at the end of a
# block and the number of rt extents is large enough to allow an allocation
# request larger than the maximum extent size, it's possible that during a
# large allocation request, the allocator will fail to constrain maxlen on the
# second run through the loop, and the rt bitmap range check will run right off
# the end of the rtbitmap file.  When this happens, xfs triggers a verifier
# error and returns EFSCORRUPTED.

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

here=`pwd`
tmp=/tmp/$$
status=1    # failure is the default!
trap "_cleanup; exit \$status" 0 1 2 3 15

_cleanup()
{
	cd /
	rm -f $tmp.*
}

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

# real QA test starts here
_supported_fs xfs
_require_scratch
_require_realtime
_require_test_program "punch-alternating"

rm -f $seqres.full

# Format filesystem to get the block size
_scratch_mkfs > $seqres.full
_scratch_mount >> $seqres.full

blksz=$(_get_block_size $SCRATCH_MNT)
rextsize=$($XFS_INFO_PROG $SCRATCH_MNT | grep realtime.*extsz | sed -e 's/^.*extsz=\([0-9]*\).*$/\1/g')
rextblks=$((rextsize / blksz))

echo "blksz $blksz rextsize $rextsize rextblks $rextblks" >> $seqres.full

_scratch_unmount

# Format filesystem with a realtime volume whose size fits the following:
# 1. Longer than (XFS MAXEXTLEN * blocksize) bytes so that a large fallocate
#    request can create a maximally sized data fork extent mapping and then
#    ask the allocator for even more blocks.
# 2. Exactly a multiple of (NBBY * blksz * rextsize) bytes.

rtsize1=$((2097151 * blksz))
rtsize2=$((8 * blksz * rextsize))
rtsize=$(( $(blockdev --getsz $SCRATCH_RTDEV) * 512 ))

echo "rtsize1 $rtsize1 rtsize2 $rtsize2 rtsize $rtsize" >> $seqres.full

test $rtsize -gt $rtsize1 || \
	_notrun "scratch rt device too small, need $rtsize1 bytes"
test $rtsize -gt $rtsize2 || \
	_notrun "scratch rt device too small, need $rtsize2 bytes"

rtsize=$((rtsize - (rtsize % rtsize2)))

echo "rt size will be $rtsize" >> $seqres.full

_scratch_mkfs -r size=$rtsize >> $seqres.full
_scratch_mount >> $seqres.full

# Make sure the root directory has rtinherit set so our test file will too
_xfs_force_bdev realtime $SCRATCH_MNT

# Allocate some stuff at the start, to force the first falloc of the ouch file
# to happen somewhere in the middle of the rt volume
$XFS_IO_PROG -f -c 'falloc 0 64m' "$SCRATCH_MNT/b"
$here/src/punch-alternating -i $((rextblks * 2)) -s $((rextblks)) "$SCRATCH_MNT/b"

avail="$(df -P "$SCRATCH_MNT" | awk 'END {print $4}')"1
toobig="$((avail * 2))"

# falloc the ouch file in the middle of the rt extent to exercise the near
# allocator in the last step.
$XFS_IO_PROG -f -c 'falloc 0 1g' "$SCRATCH_MNT/ouch"

# Try to get the near allocator to overflow on an allocation that matches
# exactly one of the rtsummary size levels.  This should return ENOSPC and
# not EFSCORRUPTED.
$XFS_IO_PROG -f -c "falloc 0 ${toobig}k" "$SCRATCH_MNT/ouch"

# success, all done
status=0
exit