tests/btrfs/026

#! /bin/bash
# FSQA Test No. 026
#
# Test that doing a direct IO write against a file range that contains one
# prealloc extent and one compressed extent works correctly.
#
#-----------------------------------------------------------------------
#
# Copyright (C) 2015 SUSE Linux Products GmbH. All Rights Reserved.
# Author: Filipe Manana <fdmanana@suse.com>
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License as
# published by the Free Software Foundation.
#
# This program is distributed in the hope that it would be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write the Free Software Foundation,
# Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
#-----------------------------------------------------------------------
#

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

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

# real QA test starts here
_supported_fs btrfs
_supported_os Linux
_require_scratch
_require_xfs_io_command "falloc"

rm -f $seqres.full

_scratch_mkfs >>$seqres.full 2>&1
_scratch_mount "-o compress"

# Create a compressed extent covering the range [700K, 800K[.
$XFS_IO_PROG -f -s -c "pwrite -S 0xaa -b 100K 700K 100K" $SCRATCH_MNT/foo \
	| _filter_xfs_io

# Create prealloc extent covering the range [600K, 700K[.
$XFS_IO_PROG -c "falloc 600K 100K" $SCRATCH_MNT/foo

# Write 80K of data to the range [640K, 720K[ using direct IO. This range covers
# both the prealloc extent and the compressed extent. Because there's a
# compressed extent in the range we are writing to, the DIO write code path ends
# up only writing the first 60k of data, which goes to the prealloc extent, and
# then falls back to buffered IO for writing the remaining 20K of data - because
# that remaining data maps to a file range containing a compressed extent.
# When falling back to buffered IO, we used to trigger an assertion when
# releasing reserved space due to bad accounting of the inode's outstanding
# extents counter, which was set to 1 but we ended up decrementing it by 1 twice,
# once through the ordered extent for the 60K of data we wrote using direct IO,
# and once through the main direct IO handler (inode.cbtrfs_direct_IO()) because
# the direct IO write wrote less than 80K of data (60K).
$XFS_IO_PROG -d -c "pwrite -S 0xbb -b 80K 640K 80K" $SCRATCH_MNT/foo \
	| _filter_xfs_io

# Now similar test as above but for very large write operations. This triggers
# special cases for an inode's outstanding extents accounting, as internally
# btrfs logically splits extents into 128Mb units.
$XFS_IO_PROG -f -s \
	-c "pwrite -S 0xaa -b 128M 258M 128M" \
	-c "falloc 0 258M" \
	$SCRATCH_MNT/bar | _filter_xfs_io
$XFS_IO_PROG -d -c "pwrite -S 0xbb -b 256M 3M 256M" $SCRATCH_MNT/bar \
	| _filter_xfs_io

# Now verify the file contents are correct and that they are the same even after
# unmounting and mounting the fs again (or evicting the page cache).
#
# For file foo, all bytes in the range [0, 640K[ must have a value of 0x00, all
# bytes in the range [640K, 720K[ must have a value of 0xbb and all bytes in the
# range [720K, 800K[ must have a value of 0xaa.
#
# For file bar, all bytes in the range [0, 3M[ must havea value of 0x00, all
# bytes in the range [3M, 259M[ must have a value of 0xbb and all bytes in the
# range [259M, 386M[ must have a value of 0xaa.
#
echo "File digests before remounting the file system:"
md5sum $SCRATCH_MNT/foo | _filter_scratch
md5sum $SCRATCH_MNT/bar | _filter_scratch
_scratch_cycle_mount
echo "File digests after remounting the file system:"
md5sum $SCRATCH_MNT/foo | _filter_scratch
md5sum $SCRATCH_MNT/bar | _filter_scratch

status=0
exit