apfstests/tests/btrfs/211

#! /bin/bash
# SPDX-License-Identifier: GPL-2.0
# Copyright (C) 2020 SUSE Linux Products GmbH. All Rights Reserved.
#
# FSQA Test No. 211
#
# Test that if we fsync a file with prealloc extents that start before and
# after the file's size, we don't end up with missing parts of the extents
# and implicit file holes after a power failure. Test both without and with
# the NO_HOLES feature.
#
seq=`basename $0`
seqres=$RESULT_DIR/$seq
echo "QA output created by $seq"
tmp=/tmp/$$
status=1	# failure is the default!
trap "_cleanup; exit \$status" 0 1 2 3 15

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

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

# real QA test starts here
_supported_fs btrfs
_require_scratch
_require_xfs_io_command "falloc" "-k"
# fiemap needed by _count_extents()
_require_xfs_io_command "fiemap"
_require_btrfs_fs_feature "no_holes"
_require_btrfs_mkfs_feature "no-holes"
_require_dm_target flakey

rm -f $seqres.full

run_test()
{
    # Create our test file with 2 consecutive prealloc extents, each with a size
    # of 128Kb, and covering the range from 0 to 256Kb, with a file size of 0.
    # Then fsync the file to record both extents in a log tree.
    $XFS_IO_PROG -f -c "falloc -k 0 128K" $SCRATCH_MNT/foo
    $XFS_IO_PROG -c "falloc -k 128K 128K" $SCRATCH_MNT/foo
    $XFS_IO_PROG -c "fsync" $SCRATCH_MNT/foo

    # Now do a redudant extent allocation for the range from 0 to 64Kb. This will
    # merely increase the file size from 0 to 64Kb. Instead we could also do a
    # truncate to set the file size to 64Kb.
    $XFS_IO_PROG -c "falloc 0 64K" $SCRATCH_MNT/foo

    # Fsync the file, so we update the log with the new file size. Here btrfs
    # used to incorrectly set the number of bytes to 64Kb for the prealloc extent
    # that covers the file range from 0 to 128Kb.
    $XFS_IO_PROG -c "fsync" $SCRATCH_MNT/foo

    # Now set the file size to 256K with a truncate and then fsync the file. We
    # want to verify the log tree doesn't end up with an implicit hole for the
    # file range from 64Kb to 128Kb. That would lead to an implicit hole after
    # replaying the log and losing part of the prealloc extent, so a future write
    # to anywhere in the file range from 64Kb to 128Kb would result in allocating
    # a new extent and not use the extent previously allocated with fallocate().
    $XFS_IO_PROG -c "truncate 256K" -c "fsync" $SCRATCH_MNT/foo

    # Simulate a power failure and then mount again the filesystem to replay the
    # log tree.
    _flakey_drop_and_remount

    # Unmount the filesystem and run 'btrfs check'/fsck to verify that we don't
    # have a missing hole for the file range from 64K to 128K.
    _unmount_flakey
    _check_scratch_fs $FLAKEY_DEV

    _mount_flakey

    # Now write to the file range from 0 to 128K. After this we should still have
    # rwo extents in our file, corresponding to the 2 extents we allocated before
    # using fallocate(). In particular writing to the file range from 64Kb to
    # 128Kb should not have allocated a new extent.
    $XFS_IO_PROG -c "pwrite -S 0xab 0 128K" $SCRATCH_MNT/foo | _filter_xfs_io
    echo "File extent count after write: $(_count_extents $SCRATCH_MNT/foo)"
}

_scratch_mkfs -O ^no-holes >>$seqres.full 2>&1
_require_metadata_journaling $SCRATCH_DEV
_init_flakey
_mount_flakey

echo "Testing without NO_HOLES feature"
run_test

_unmount_flakey
_cleanup_flakey

_scratch_mkfs -O no-holes >>$seqres.full 2>&1
_require_metadata_journaling $SCRATCH_DEV
_init_flakey
_mount_flakey

echo
echo "Testing with the NO_HOLES feature"
run_test

_unmount_flakey
status=0
exit