tests/btrfs/316

#! /bin/bash
# SPDX-License-Identifier: GPL-2.0
# Copyright (C) 2024 SUSE Linux Products GmbH. All Rights Reserved.
#
# FS QA Test 316
#
# Make sure btrfs qgroup won't leak its reserved data space if qgroup is
# marked inconsistent.
#
# This exercises a regression introduced in v6.1 kernel by the following commit:
#
# e15e9f43c7ca ("btrfs: introduce BTRFS_QGROUP_RUNTIME_FLAG_NO_ACCOUNTING to skip qgroup accounting")
#
. ./common/preamble
_begin_fstest auto quick qgroup

_supported_fs btrfs
_require_scratch

_fixed_by_kernel_commit xxxxxxxxxxxx \
	"btrfs: qgroup: always free reserved space for extent records"

_scratch_mkfs >> $seqres.full
_scratch_mount

$BTRFS_UTIL_PROG quota enable $SCRATCH_MNT
$BTRFS_UTIL_PROG quota rescan -w $SCRATCH_MNT >> $seqres.full

$BTRFS_UTIL_PROG qgroup create 1/0 $SCRATCH_MNT >> $seqres.full
$BTRFS_UTIL_PROG subvolume create $SCRATCH_MNT/subv1 >> $seqres.full

# This would mark qgroup inconsistent, as the snapshot belongs to a different
# higher level qgroup, we have to do full rescan on both source and snapshot.
# This can be very slow for large subvolumes, so btrfs only marks qgroup
# inconsistent and let users to determine when to do a full rescan
$BTRFS_UTIL_PROG subvolume snapshot -i 1/0 $SCRATCH_MNT/subv1 $SCRATCH_MNT/snap1 >> $seqres.full

# This write would lead to a qgroup extent record holding the reserved 128K.
# And for unpatched kernels, the reserved space would not be freed properly
# due to qgroup is inconsistent.
_pwrite_byte 0xcd 0 128K $SCRATCH_MNT/foobar >> $seqres.full

# The qgroup leak detection is only triggered at unmount time.
_scratch_unmount

# Check the dmesg warning for data rsv leak.
#
# If CONFIG_BTRFS_DEBUG is enabled, we would have a kernel warning with
# backtrace, but for release builds, it's just a warning line.
# So here we manually check the warning message.
if _dmesg_since_test_start | grep -q "leak"; then
	_fail "qgroup data reserved space leaked"
fi

echo "Silence is golden"

# success, all done
status=0
exit