qemu/tests/qemu-iotests/024
Stefan Hajnoczi dd0c35d69b qemu-iotests: Use zero-based offsets for IO patterns
The io_pattern style functions have the following loop:

  for i in `seq 1 $count`; do
      echo ... $(( start + i * step )) ...
  done

Offsets are 1-based so start=1024, step=512, count=4 yields:
1536, 2048, 2560, 3072

Normally we expect:
1024, 1536, 2048, 2560

Most tests ignore this detail, which means that they perform I/O to a
slightly different range than expected by the test author.

Later on things got less innocent and tests started trying to compensate
for the 1-based indexing.  This included negative start values in test
024 and my own attempt with count-1 in test 028!

The end result is that tests that use io_pattern are hard to reason
about and don't work the way you'd expect.  It's time to clean this mess
up.

This patch switches io_pattern to 0-based offsets.  This requires
adjusting the golden outputs since I/O ranges are now shifted and output
differs.

Verifying these output diffs is easy, however.  Each diff hunk moves one
I/O from beyond the end of the pattern range to the beginning.

Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
2012-02-23 10:29:46 +01:00

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#!/bin/bash
#
# Rebasing COW images
#
# Copyright (C) 2009 Red Hat, Inc.
#
# 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/>.
#
# creator
owner=kwolf@redhat.com
seq=`basename $0`
echo "QA output created by $seq"
here=`pwd`
tmp=/tmp/$$
status=1 # failure is the default!
_cleanup()
{
_cleanup_test_img
rm -f $TEST_DIR/t.$IMGFMT.base_old
rm -f $TEST_DIR/t.$IMGFMT.base_new
}
trap "_cleanup; exit \$status" 0 1 2 3 15
# get standard environment, filters and checks
. ./common.rc
. ./common.filter
. ./common.pattern
# Currently only qcow2 and qed support rebasing
_supported_fmt qcow2 qed
_supported_proto generic
_supported_os Linux
CLUSTER_SIZE=65536
# Cluster allocations to be tested:
#
# Backing (old) 11 -- 11 -- 11 -- 11 --
# Backing (new) 22 22 -- -- 22 22 -- --
# COW image 33 33 33 33 -- -- -- --
#
# The pattern is written twice to have both an alloc -> non-alloc and a
# non-alloc -> alloc transition in the COW image.
echo "Creating backing file"
echo
_make_test_img 1G
io_pattern writev 0 $CLUSTER_SIZE $((2 * CLUSTER_SIZE)) 8 0x11
mv $TEST_IMG $TEST_IMG.base_old
echo "Creating new backing file"
echo
_make_test_img 1G
io_pattern writev 0 $((2 * CLUSTER_SIZE)) $((4 * CLUSTER_SIZE)) 4 0x22
mv $TEST_IMG $TEST_IMG.base_new
echo "Creating COW image"
echo
_make_test_img -b $TEST_IMG.base_old 1G
io_pattern writev 0 $((4 * CLUSTER_SIZE)) 0 1 0x33
io_pattern writev $((8 * CLUSTER_SIZE)) $((4 * CLUSTER_SIZE)) 0 1 0x33
echo "Read before the rebase to make sure everything is set up correctly"
echo
io_pattern readv $((0 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
io_pattern readv $((1 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
io_pattern readv $((2 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
io_pattern readv $((3 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
io_pattern readv $((4 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x11
io_pattern readv $((5 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x00
io_pattern readv $((6 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x11
io_pattern readv $((7 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x00
io_pattern readv $((8 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
io_pattern readv $((9 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
io_pattern readv $((10 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
io_pattern readv $((11 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
io_pattern readv $((12 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x11
io_pattern readv $((13 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x00
io_pattern readv $((14 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x11
io_pattern readv $((15 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x00
echo
echo Rebase and test again
echo
$QEMU_IMG rebase -b $TEST_IMG.base_new $TEST_IMG
io_pattern readv $((0 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
io_pattern readv $((1 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
io_pattern readv $((2 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
io_pattern readv $((3 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
io_pattern readv $((4 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x11
io_pattern readv $((5 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x00
io_pattern readv $((6 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x11
io_pattern readv $((7 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x00
io_pattern readv $((8 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
io_pattern readv $((9 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
io_pattern readv $((10 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
io_pattern readv $((11 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
io_pattern readv $((12 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x11
io_pattern readv $((13 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x00
io_pattern readv $((14 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x11
io_pattern readv $((15 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x00
# success, all done
echo "*** done"
rm -f $seq.full
status=0