tests/qemu-iotests/tests/iov-padding

#!/usr/bin/env bash
# group: rw quick
#
# Check the interaction of request padding (to fit alignment restrictions) with
# vectored I/O from the guest
#
# Copyright Red Hat
#
# 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; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will 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, see <http://www.gnu.org/licenses/>.
#

seq=$(basename $0)
echo "QA output created by $seq"

status=1	# failure is the default!

_cleanup()
{
    _cleanup_test_img
}
trap "_cleanup; exit \$status" 0 1 2 3 15

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

_supported_fmt raw
_supported_proto file

_make_test_img 1M

IMGSPEC="driver=blkdebug,align=4096,image.driver=file,image.filename=$TEST_IMG"

# Four combinations:
# - Offset 4096, length 1023 * 512 + 512: Fully aligned to 4k
# - Offset 4096, length 1023 * 512 + 4096: Head is aligned, tail is not
# - Offset 512, length 1023 * 512 + 512: Neither head nor tail are aligned
# - Offset 512, length 1023 * 512 + 4096: Tail is aligned, head is not
for start_offset in 4096 512; do
    for last_element_length in 512 4096; do
        length=$((1023 * 512 + $last_element_length))

        echo
        echo "== performing 1024-element vectored requests to image (offset: $start_offset; length: $length) =="

        # Fill with data for testing
        $QEMU_IO -c 'write -P 1 0 1M' "$TEST_IMG" | _filter_qemu_io

        # 1023 512-byte buffers, and then one with length $last_element_length
        cmd_params="-P 2 $start_offset $(yes 512 | head -n 1023 | tr '\n' ' ') $last_element_length"
        QEMU_IO_OPTIONS="$QEMU_IO_OPTIONS_NO_FMT" $QEMU_IO \
            -c "writev $cmd_params" \
            --image-opts \
            "$IMGSPEC" \
            | _filter_qemu_io

        # Read all patterns -- read the part we just wrote with writev twice,
        # once "normally", and once with a readv, so we see that that works, too
        QEMU_IO_OPTIONS="$QEMU_IO_OPTIONS_NO_FMT" $QEMU_IO \
            -c "read -P 1 0 $start_offset" \
            -c "read -P 2 $start_offset $length" \
            -c "readv $cmd_params" \
            -c "read -P 1 $((start_offset + length)) $((1024 * 1024 - length - start_offset))" \
            --image-opts \
            "$IMGSPEC" \
            | _filter_qemu_io
    done
done

# success, all done
echo "*** done"
rm -f $seq.full
status=0