tests/generic/315

#! /bin/bash
# SPDX-License-Identifier: GPL-2.0
# Copyright (c) 2013 Oracle, Inc.  All Rights Reserved.
#
# FS QA Test No. 315
#
# fallocate/truncate tests with FALLOC_FL_KEEP_SIZE option.
# Verify if the disk space is released after truncating a file back
# to the old smaller size.  Before Linux 3.10, Btrfs/OCFS2 are test
# failed in this case.
#
. ./common/preamble
_begin_fstest auto quick rw prealloc

status=0	# success is the default!

# Import common functions.
. ./common/filter


# Modify as appropriate.
_require_test
_require_xfs_io_command "falloc" "-k"

echo "Slience is golden"

# Check the current avaliable disk space on $TEST_DIR.
# 1024KiB at least
avail_begin=`df -P $TEST_DIR | awk 'END {print $4}'`
[ "$avail_begin" -ge 1024 ] || _notrun "Test device is too small ($avail_begin KiB)"

# Preallocate half size of the available disk space to a file
# starts from offset 0 with FALLOC_FL_KEEP_SIZE option on the
# test file system.
$XFS_IO_PROG -f -c 'falloc -k 0 $(($avail_begin/2))' \
	$TEST_DIR/testfile.$seq >>$seqres.full 2>&1

# Verify the file size, it should keep unchanged as 0 in this case
fsize=`_get_filesize $TEST_DIR/testfile.$seq`
[ "$fsize" -eq 0 ] || _fail "File size is changed to ($fsize Bytes)"

# Truncate the file size back to 0
truncate -s 0 $TEST_DIR/testfile.$seq
_test_sync

# Preallocated disk space should be released
avail_done=`df -P $TEST_DIR | awk 'END {print $4}'`
_within_tolerance "df" $avail_done $avail_begin 1%
[ $? -eq 0 ] || _fail "Available disk space ($avail_done KiB) wanted ($avail_begin KiB)"

# success, all done
exit