#! /bin/bash
# SPDX-License-Identifier: GPL-2.0
# Copyright (C) 2019 SUSE Linux Products GmbH. All Rights Reserved.
#
# FS QA Test 194
#
# Test if btrfs can handle large device ids.
#
# The regression is introduced by kernel commit ab4ba2e13346 ("btrfs:
# tree-checker: Verify dev item").
# The fix is titled: "btrfs: tree-checker: Fix wrong check on max devid"
#
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

# remove previous $seqres.full before test
rm -f $seqres.full

# real QA test starts here

# Modify as appropriate.
_supported_fs btrfs
_require_scratch_dev_pool 2
_scratch_dev_pool_get 2

# Here we use 4k node size to reduce runtime (explained near _scratch_mkfs call)
# To use the minimal node size (4k) we need 4K page size.
if [ $(get_page_size) != 4096 ]; then
	_notrun "This test need 4k page size"
fi

device_1=$(echo $SCRATCH_DEV_POOL | awk '{print $1}')
device_2=$(echo $SCRATCH_DEV_POOL | awk '{print $2}')

echo device_1=$device_1 device_2=$device_2 >> $seqres.full

# The wrong check limit is based on the max item size (BTRFS_MAX_DEVS() macro),
# and max item size is based on node size, so smaller node size will result
# much shorter runtime. So here we use minimal node size (4K) to reduce runtime.
_scratch_mkfs -n 4k >> $seqres.full
_scratch_mount

# For 4k nodesize, the wrong limit is calculated by:
# ((4096 - 101 - 25 - 80) / 32) + 1
#    |      |    |    |     |- sizeof(btrfs_stripe)
#    |      |    |    |- sizeof(btrfs_chunk)
#    |      |    |- sizeof(btrfs_item)
#    |      |- sizeof(btrfs_header)
#    |- node size
# Which is 122.
#
# The old limit is wrong because it doesn't take devid holes into consideration.
# We can have large devid, but still have only 1 device.
#
# Add and remove device in a loop, each iteration will increase devid by 2.
# So by 64 iterations, we will definitely hit that 122 limit.
for (( i = 0; i < 64; i++ )); do
	$BTRFS_UTIL_PROG device add -f $device_2 $SCRATCH_MNT
	$BTRFS_UTIL_PROG device del $device_1 $SCRATCH_MNT
	$BTRFS_UTIL_PROG device add -f $device_1 $SCRATCH_MNT
	$BTRFS_UTIL_PROG device del $device_2 $SCRATCH_MNT
done
_scratch_dev_pool_put

echo "Silence is golden"

# success, all done
status=0
exit